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Sample records for brachial-ankle pulse wave

  1. Correlation of Arterial Stiffness and Bone Mineral Density by Measuring Brachial-Ankle Pulse Wave Velocity in Healthy Korean Women

    OpenAIRE

    Kim, Nam-Lee; Suh, Heuy-Sun

    2015-01-01

    Background An association between arterial stiffness and osteoporosis has previously been reported. Therefore, we investigated the relationship between arterial stiffness, measured by brachial-ankle pulse wave velocity, and bone mineral density in a sample of healthy women undergoing routine medical checkup. Methods We retrospectively reviewed the medical charts of 135 women who had visited the Health Promotion Center (between May 2009 and December 2012). Brachial-ankle pulse wave velocity wa...

  2. Aging Index using Photoplethysmography for a Healthcare Device: Comparison with Brachial-Ankle Pulse Wave Velocity

    OpenAIRE

    Hong, Kyung Soon; Park, Kyu Tae; Ahn, Jae Mok

    2015-01-01

    Objectives Recent studies have emphasized the potential information embedded in peripheral fingertip photoplethysmogram (PPG) signals for the assessment of arterial wall stiffening during aging. For the discrimination of arterial stiffness with age, the brachial-ankle pulse wave velocity (baPWV) has been widely used in clinical applications. The second derivative of the PPG (acceleration photoplethysmogram [APG]) has been reported to correlate with the presence of atherosclerotic disorders. I...

  3. Relationship between brachial-ankle pulse wave velocity and metabolic syndrome components in a Chinese population

    OpenAIRE

    Zhou, Fang; Zhang, Haifeng; Yao, Wenming; Mei, Hongbin; Xu, Dongjie; Sheng, Yanhui; Yang, Rong; Kong, Xiangqing; Wang, Liansheng; Zou, Jiangang; Yang, Zhijian; Li, Xinli

    2014-01-01

    Abstract The purpose of this study was to assess the relationship between arterial stiffness, as measured by brachial-ankle pulse wave velocity (baPWV), and the presence of the metabolic syndrome (MS) in a Chinese population. A total of 4,445 subjects were enrolled. The prevalence of MS in our study population was 21.7%, 17.2% and 25.6% for the general population, males and females, respectively. With adjustments for age, gender, cigarette smoking, heart rate, total cholesterol, low-density l...

  4. Relationships between Brachial-Ankle Pulse Wave Velocity and Peripheral Neuropathy in Type 2 Diabetes

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    Byung Kil Ha

    2012-12-01

    Full Text Available BackgroundBrachial-ankle pulse wave velocity (baPWV is known to be a good surrogate marker of clinical atherosclerosis. Atherosclerosis is a major predictor for developing neuropathy. The goal of this study was to determine the relationship between baPWV and diabetic peripheral neuropathy (DPN in patients with type 2 diabetes.MethodsA retrospective cross-sectional study was conducted involving 692 patients with type 2 diabetes. The correlation between increased baPWV and DPN, neurological symptoms, and neurological assessment was analyzed. DPN was examined using the total symptom score (TSS, ankle reflexes, the vibration test, and the 10-g monofilament test. DPN was defined as TSS ≥2 and an abnormal neurological assessment. Data were expressed as means±standard deviation for normally distributed data and as median (interquartile range for non-normally distributed data. Independent t-tests or chi-square tests were used to make comparisons between groups, and a multiple logistic regression test was used to evaluate independent predictors of DPN. The Mantel-Haenszel chi-square test was used to adjust for age.ResultsPatients with DPN had higher baPWV and systolic blood pressure, and were more likely to be older and female, when compared to the control group. According to univariate analysis of risk factors for DPN, the odds ratio of the baPWV ≥1,600 cm/sec was 1.611 (95% confidence interval [CI], 1.072 to 2.422; P=0.021 and the odds ratio in female was 1.816 (95% CI, 1.195 to 2.760; P=0.005.ConclusionIncreased baPWV was significantly correlated with peripheral neuropathy in patients with type 2 diabetes.

  5. Can we early diagnose metabolic syndrome using brachial-ankle pulse wave velocity in community population?

    Institute of Scientific and Technical Information of China (English)

    Li Xin; Zheng Liang; Wu Juanli; Ma Yunsheng; Masanori Munakata; Oleski Jessica; Zhang Lijuan

    2014-01-01

    Background The prevalence of metabolic syndrome (MetS) increased recently and there was still not a screening index to predict MetS.The aim of this study was to estimate whether brachial-ankle pulse wave velocity (baPVVV),a novel marker for systemic arterial stiffness,could predict MetS in Chinese community population.Methods A total of 2 191 participants were recruited and underwent medical examination including 1 455 men and 756 women from June 2011 to January 2012.MetS was diagnosed according to the criteria of the International Diabetes Federation (IDF).Multiple Logistic regressions were conducted to explore the risk factors of MetS.Receiver operating characteristic (ROC) curve was performed to estimate the ideal diagnostic cutoff point of baPWV to predict MetS.Results The mean age was (45.35±8.27) years old.In multiple Logistic regression analysis,the gender,baPWV and smoking status were risk factors to MetS after adjusting age,gender,baPWV,walk time and sleeping time.The prevalence of MetS was 17.48% in 30-year age population in Shanghai.There were significant differences (X2=96.46,P <0.05) between male and female participants on MetS prevalence.According to the ROC analyses,the ideal cutoff point of baPWV was 1 358.50 cm/s (AUC=60.20%) to predict MetS among male group and 1 350.00 cm/s (AUC=70.90%) among female group.Conclusion BaPWV may be considered as a screening marker to predict MetS in community Chinese population and the diagnostic value of 1 350.00 cm/s was more significant for the female group.

  6. THE EFFECT OF REGULAR EXERCISE TRAINING DURING PREGNANCY ON POSTPARTUM BRACHIAL-ANKLE PULSE WAVE VELOCITY, A MEASURE OF ARTERIAL STIFFNESS

    OpenAIRE

    Ikuno Kawabata; Akihito Nakai; Atsuko Sekiguchi; Yuko Inoue; Toshiyuki Takeshita

    2012-01-01

    The aim of our study was to use brachial-ankle pulse wave velocity (baPWV) measurements to noninvasively assess the effect of exercise training on arterial stiffness in normal pregnant women. Arterial stiffness was assessed at the beginning of the early second trimester of pregnancy and 1 month after delivery in 17 women with normal singleton pregnancies who exercised regularly throughout pregnancy: 81 matched controls were used for comparison. No significant differences were observed in baPW...

  7. Effects of Levocarnitine on Brachial-Ankle Pulse Wave Velocity in Hemodialysis Patients: A Randomized Controlled Trial

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    Terumi Higuchi

    2014-12-01

    Full Text Available Background and Aims: Atherosclerotic cardiovascular disease is the most common cause of mortality in patients with end-stage kidney disease. Chronic kidney disease patients often exhibit a deficiency in l-carnitine due to loss during hemodialysis (HD. We studied the effects of l-carnitine supplementation on brachial-ankle pulse wave velocity (baPWV, a marker of atherosclerosis, in HD patients. Methods: This was a prospective, open-label, randomized, parallel controlled, multi-center trial testing the anti-atherosclerotic efficacy of oral l-carnitine administration (20 mg/kg/day. HD patients (n = 176, mean age, 67.2 ± 10.3 years old; mean duration of HD, 54 ± 51 months with plasma free l-carnitine deficiency (<40 μmol/L were randomly assigned to the oral l-carnitine group (n = 88 or control group (n = 88 and monitored during 12 months of treatment. Results: There were no significant differences in baseline clinical variables between the l-carnitine and control groups. l-carnitine supplementation for 12 months significantly increased total, free, and acyl carnitine levels, and reduced the acyl/free carnitine ratio. The baPWV value decreased from 2085 ± 478 cm/s at baseline to 1972 ± 440 cm/s after six months (p < 0.05 to 1933 ± 363 cm/s after 12 months (p < 0.001 of l-carnitine administration, while no significant changes in baPWV were observed in the control group. Baseline baPWV was the only factor significantly correlated with the decrease in baPWV. Conclusions: l-carnitine supplementation significantly reduced baPWV in HD patients. l-carnitine may be a novel therapeutic strategy for preventing the progression of atherosclerotic cardiovascular disease.

  8. Association of Brachial-Ankle Pulse Wave Velocity and Cardiomegaly With Aortic Arch Calcification in Patients on Hemodialysis.

    Science.gov (United States)

    Shin, Ming-Chen Paul; Lee, Mei-Yueh; Huang, Jiun-Chi; Tsai, Yi-Chun; Chen, Jui-Hsin; Chen, Szu-Chia; Chang, Jer-Ming; Chen, Hung-Chun

    2016-05-01

    Aortic arch calcification (AoAC) is associated with cardiovascular and all-cause mortality in end-stage renal disease population. AoAC can be simply estimated with an AoAC score using plain chest radiography. The objective of this study is to evaluate the association of AoAC with brachial-ankle pulse wave velocity (baPWV) and cardiomegaly in patients who have undergoing hemodialysis (HD).We retrospectively determined AoAC and cardiothoracic ratio (CTR) by chest x-ray in 220 HD patients who underwent the measurement of baPWV. The values of baPWV were measured by an ankle-brachial index-form device. Multiple stepwise logistic regression analysis was used to identify the factors associated with AoAC score >4.Compared patients with AoAC score ≦4, patients with AoAC score >4 had older age, higher prevalence of diabetes and cerebrovascular disease, lower diastolic blood pressure, higher baPWV, higher CTR, higher prevalence of CTR ≧50%, lower total cholesterol, and lower creatinine level. After the multivariate stepwise logistic analysis, old age, cerebrovascular disease, high baPWV (per 100 cm/s, odds ratio [OR] 1.065, 95% confidence interval [CI] 1.003-1.129, P = 0.038), CTR (per 1%, OR 1.116, 95% CI 1.046-1.191, P = 0.001), and low total cholesterol level were independently associated with AoAC score >4.Our study demonstrated AoAC severity was associated with high baPWV and high CTR in patients with HD. Therefore, we suggest that evaluating AoAC on plain chest radiography may be a simple and inexpensive method for detecting arterial stiffness in HD patients. PMID:27175684

  9. Relationship Between Earlobe Crease and Brachial-ankle Pulse Wave Velocity in Non-hypertensive, Non-diabetic Adults in Korea

    OpenAIRE

    Choi, Sang In; Kang, Hee Cheol; Kim, Choon Ok; Lee, Seung Beom; Hwang, Won Ju; Kang, Dae Ryong

    2009-01-01

    OBJECTIVES Several studies have found a significant association between the presence of earlobe crease (ELC) and cardiovascular disease (CVD). Brachial-ankle Pulse Wave Velocity (baPWV) is a non-invasive and useful measure of arterial stiffness predicting cardiovascular events and mortality. However, few studies have reported the relationship between ELC and baPWV as a new measure of arterial stiffness. The purpose of this study was to determine whether ELC is related to baPWV in non-diabetic...

  10. The product of resting heart rate times blood pressure is associated with high brachial-ankle pulse wave velocity.

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    Anxin Wang

    Full Text Available OBJECTIVE: To investigate potential associations between resting heart rate, blood pressure and the product of both, and the brachial-ankle pulse wave velocity (baPWV as a maker of arterial stiffness. METHODS: The community-based "Asymptomatic Polyvascular Abnormalities in Community (APAC Study" examined asymptomatic polyvascular abnormalities in a general Chinese population and included participants with an age of 40+ years without history of stroke and coronary heart disease. Arterial stiffness was defined as baPWV≥1400 cm/s. We measured and calculated the product of resting heart rate and systolic blood pressure (RHR-SBP and the product of resting heart rate and mean arterial pressure (RHR-MAP. RESULTS: The study included 5153 participants with a mean age of 55.1 ± 11.8 years. Mean baPWV was 1586 ± 400 cm/s. Significant (P<0.0001 linear relationships were found between higher baPWV and higher resting heart rate or higher arterial blood pressure, with the highest baPWV observed in individuals from the highest quartiles of resting heart rate and blood pressure. After adjusting for confounding parameters such as age, sex, educational level, body mass index, fasting blood concentrations of glucose, blood lipids and high-sensitive C-reactive protein, smoking status and alcohol consumption, prevalence of arterial stiffness increased significantly (P<0.0001 with increasing RHR-SBP quartile (Odds Ratio (OR: 2.72;95%Confidence interval (CI:1.46,5.08 and increasing RHR-MAP (OR:2.10;95%CI:1.18,3.72. Similar results were obtained in multivariate linear regression analyses with baPWV as continuous variable. CONCLUSIONS: Higher baPWV as a marker of arterial stiffness was associated with a higher product of RHR-SBP and RHR-MAP in multivariate analysis. In addition to other vascular risk factors, higher resting heart rate in combination with higher blood pressure are risk factors for arterial stiffness.

  11. Relationship between resistant hypertension and arterial stiffness assessed by brachial-ankle pulse wave velocity in the older patient

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    Chung CM

    2014-09-01

    Full Text Available Chang-Min Chung,1,2 Hui-Wen Cheng,2 Jung-Jung Chang,2 Yu-Sheng Lin,2 Ju-Feng Hsiao,2 Shih-Tai Chang,1 Jen-Te Hsu2,31School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, 2Division of Cardiology, Chang Gung Memorial Hospital, Chiayi, 3Department of Medicine, College of Medicine, Chang Gung University, Taoyuan County, TaiwanBackground: Resistant hypertension (RH is a common clinical condition associated with increased cardiovascular mortality and morbidity in older patients. Several factors and conditions interfering with blood pressure (BP control, such as excess sodium intake, obesity, diabetes, older age, kidney disease, and certain identifiable causes of hypertension are common in patients resistant to antihypertensive treatment. Arterial stiffness, measured by brachial-ankle pulse wave velocity (baPWV, is increasingly recognized as an important prognostic index and potential therapeutic target in hypertensive patients. The aim of this study was to determine whether there is an association between RH and arterial stiffness. Methods: This study included 1,620 patients aged ≥65 years who were referred or self-referred to the outpatient hypertension unit located at a single cardiovascular center. They were separated into normotensive, controlled BP, and resistant hypertension groups. Home BP, blood laboratory parameters, echocardiographic studies and baPWV all were measured. Results: The likelihood of diabetes mellitus was significantly greater in the RH group than in the group with controlled BP (odds ratio 2.114, 95% confidence interval [CI] 1.194–3.744, P=0.010. Systolic BP was correlated in the RH group significantly more than in the group with controlled BP (odds ratio 1.032, 95% CI 1.012–1.053, P=0.001. baPWV (odds ratio 1.084, 95% CI 1.016–1.156, P=0.015 was significantly correlated with the presence of RH. The other factors were negatively correlated with the existence of RH.Conclusion: In

  12. Periodontal disease and atherosclerosis from the viewpoint of the relationship between community periodontal index of treatment needs and brachial-ankle pulse wave velocity

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    Hoshi Keika

    2006-05-01

    Full Text Available Abstract Background It has been suggested that periodontal disease may be an independent risk factor for the development of atherosclerosis. However, the relationship between periodontal disease and atherosclerosis has not been fully elucidated. This study aimed to assess the effects of periodontal disease on atherosclerosis. Methods The study design was a cross-sectional study. Subjects were 291 healthy male workers in Japan. We used the Community Periodontal Index of Treatment Needs (CPITN score, average probing depth and gingival bleeding index (rate of bleeding gums to assess the severity of periodontal disease. We also used the Brachial-Ankle Pulse Wave Velocity (baPWV as the index for the development of atherosclerosis. Results The unadjusted odds ratio (OR of atherosclerosis in relation to the CPITN score was 1.41 [95% CI: 1.16–1.73]. However, after adjustment for age, systolic blood pressure and smoking, the CPITN score had no relationship with atherosclerosis (adjusted OR: 0.91 [0.68–1.20]. Conclusion Our results show no relationship between mild periodontal disease and atherosclerosis after appropriate adjustments.

  13. Effect of blood lipid on the change of brachial-ankle pulse wave velocity among prehypertensive population%血脂水平对血压正常高值人群脉搏波传导速度的影响

    Institute of Scientific and Technical Information of China (English)

    王林; 帅平; 刘玉萍; 程幼夫; 杨华; 李婷欣; 龚立荣; 任姣姣; 王洪佳

    2014-01-01

    Objective To explore the effect of blood lipid and lipoprotein ratios on the change of brachial-ankle pulse wave velocity (baPWV) among prehypertensive subjects.Methods 11 611 subjects with normal blood pressure (BP) were divided into two groups,which was one with optimal blood pressure (B P < 120/80 mmHg) and the other with prehypertension (BP:120-139/80-89 mmHg).Height,weight,baPWV,fasting blood-glucose,TC,TG,LDL-C and HDL-C were detected.Results The abnormal rate ofbaPWV in prehypertension group was obviously higher than that in the optimal blood pressure group.For optimal blood pressure group,the abnormality of TG,TC,LDL-C,TC/HDL-C as well as LDL-C/HDL-C,caused the increase of baPWV significantly (P<0.001).For prehypertensive group,the abnormality of TC and LDL-C caused the significant increase of baPWV (P<0.001).Results from logistic regression analysis showed that except for age,BMI and fasting blood-glucose,TC/HDL-C increasing was the independent risk factor in optimal blood pressure group,while TG increasing was for the prehypertension group.Conclusion With different normal BP level,both abnormality of blood lipid and lipoprotein ratio were the independent risk factors for baPWV increasing.%目的 探讨血脂和脂蛋白比值对血压正常高值人群脉搏波传导速度的影响.方法 选择11 611名血压正常的健康体检者,分为正常血压值组(血压< 120/80 mmHg)和血压正常高值组(血压为120 ~ 139/80 ~ 89 mmHg).应用全自动动脉硬化仪测定人选者肱踝脉搏波传导速度(baPWV),同时测量身高、体重、FPG、TC、TG、HDL-C、LDL-C等指标,并计算HDL-C和TC/HDL-C比值、LDL-C/HDL-C比值.分析血脂和脂蛋白比值异常情况对不同血压组脉搏波传导速度的影响.结果 血压正常高值组的baPWV异常率均高于血压正常组.血压正常组中除HDL-C外,TC、TG、LDL-C、TC/HDL-C、LDL-C/HDL-C的升高均使baPWV的异常率显著增加(P<0.001).血压正常高值组中,TC

  14. Relationship between resting heart rate and brachial-ankle pulse wave velocity in healthy Chinese population%静息心率与臂踝脉搏波传导速度的关系

    Institute of Scientific and Technical Information of China (English)

    陶杰; 李冬青; 董岩; 吴寿岭

    2014-01-01

    Objective To investigate the relationship between resting heart rate (RHR) and brachial-ankle pulse wave velocity (baPWV) in healthy Chinese population.Methods This was a retrospective cohort study,and a total of 5 852 participants were selected with stratified random sampling from the 101 510 workers of Tangshan Kailuan company who received the health examination during 2010-2011 including epidemiological investigation,biochemical indicators measurement and baPWV measurement.A total of 5 440 participants met the inclusion criteria (aged 40 years or older,without stroke,transient ischemic attack and myocardial infarction) and 5 153 participants (3 110 males,mean age (55.1 ± 11.8) years old) with integral data were finally recruited into the final analysis.The observation population was divided into four groups according to RHR collected during health examinations:quartile 1 (RHR≤63 beats/min,n =1 405) ; quartile 2 (63 beats/min < RHR≤69 beats/min,n =1 176) ; quartile 3 (69 beats/min < RHR ≤76 beats/min,n =1 322) ; quartile 4 (RHR > 76 beats/min,n =1 250).Multivariate logistic regression analysis was used to analyze the relationship between RHR and baPWV.Results (1) The mean baPWV was (1 586 ± 400) cm/s,and the detection rates of baPWV ≥1 400 cm/s was 61.8% (3 185/5 153).(2)The baPWV of quartile 1,2,3 and 4 were (1 511 ±338) cm/s,(1 533 ±329) cm/s,(1 574 ±368) cm/s and (1 734 ±462) cm/s,respectively,and the detection rates of baPWV≥ 1 400 cm/s were 54.7% (769/1 405),56.0% (658/1 176),63.1% (834/1 322) and 74.3%(929/1 150),respectively.(3) Multiple logistic regression analysis showed that the detection rates of baPWV were significantly higher in quartile 2,3 and 4 compared to quartile 1,and the OR values were 1.37 (95 % CI:1.11-1.69),1.96 (95 % CI:1.59-2.41) and 2.60 (95 % CI:2.07-3.25),respectively,after adjusting for age,gender and systolic blood pressure,body mass index,fasting blood glucose,triglyceride,total cholesterol

  15. Relationship between Blood Pressure Variability and Brachial-ankle Pulse Wave Velocity in Hypertensive Patients%高血压患者血压变异性与肱踝脉搏波传导速度的关系研究

    Institute of Scientific and Technical Information of China (English)

    王宁; 余振球

    2012-01-01

    目的 探讨高血压患者血压变异性与肱踝脉搏波传导速度(brachial-ankle pulse wave velocity,baPWV)的关系.方法 选择原发性高血压患者313例,根据baPWV值,将其分为两组:baPWV正常组(baPWV<1 400 cm/s)87例,baPWV升高组(baPWV≥1 400 cm/s)226例.比较两组患者年龄、性别构成比、血糖、血脂、血肌酐、血尿酸、血压及血压变异性.结果 单因素分析显示,baPWV升高组患者的年龄、胆固醇、低密度脂蛋白、高密度脂蛋白、24 h平均收缩压、24 h收缩压变异性及24 h舒张压变异性均高于baPWV正常组(P<0.05),代入Logistic回归分析显示年龄、胆固醇、高密度脂蛋白、24 h平均收缩压、24 h收缩压变异性及24 h舒张压变异性与baPWV呈相关性(P<0.05).结论 高血压患者24 h收缩压变异性和舒张压变异性是影响baPWV的独立因素.%Objective To explore the relationship between blood pressure variability and brachial - ankle pulse wave velocity ( baPWV ) in hypertensive patients. Methods Totally 313 patients with essential hypertension were enrolled in this study and divided into normal baPWV group ( baPWV < 1 400cm/s, n =87 ) and high baPWV group ( baPWV≥1 400cm/s, n= 226 ) based on their baPWV values. Age, gender ratio, fasting blood glucose ( FBG ), blood lipids including cholesterol ( CHO ), low - density lipoprotein cholesterol ( LDL ), and high - density lipoprotein cholesterol ( HDL ), serum creatinine ( Cr ), blood uric acid ( UA ), blood pressure, and blood pressure variability were measured. Results Univariate analysis revealed that age, CHO, LDL, HDL, 24 - hour systolic blood pressure, 24 - hour systolic blood pressure variability, and 24 -hour diastolic blood pressure variability were significantly higher in high baPWV group than in normal baPWV group ( P <0. 05 ). Multivariate Logistic regression analysis indicated that age, CHO, HDL, 24 -hour systolic blood pressure, 24 -hour systolic blood pressure variability

  16. Clinical significance of brachial-ankle pulse wave velocity in healthy people classified by blood pressure and age%以年龄和血压分类的健康人群臂-踝脉搏波速度参考值的临床意义

    Institute of Scientific and Technical Information of China (English)

    陈大伟; 张婧; 姜树强; 刘超; 郑海芳; 靳英; 韩春雷; 王建昌

    2015-01-01

    目的:探讨以年龄和血压分类的一般健康人群的臂-踝脉搏波传导速度(baPWV)参考值的临床意义。方法选取30岁以上无心脑血管疾病的1750名健康体检者,收集 baPWV、血压、血糖、血脂、体质量指数、吸烟、饮酒及服药史等资料。结果校正年龄和血压后,糖尿病、降压和降脂药物与 baPWV 相关,排除这些因素的1237人作为参考值人群。baPWV 参考值随年龄和血压增加而增加。结论一般健康人群按年龄和血压分类的 baPWV 参考值,可为不同年龄段和血压状态下的健康体检人群判定 baPWV 检测结果和积极防治动脉硬化提供依据。%Objective To investigate the clinical significance of brachial-ankle pulse wave velocity(baP-WV)in healthy people who were classified by blood pressure and age.Methods A total of 1750 healthy subjects without cerebral-cardiovascular diseases in the physical examination were recruited.The data of baPWV,blood pres-sure,glucose,lipid,body mass index,smoking,alcohol drinking and drugs were collected.Results After adjusting for age and blood pressure,the diabetes,drugs for anti-hypertensive drugs and lipid-lowering drugs were related with baP-WV,and the rest 1237 persons without these factors were selected as control group.Conclusion The study provides the reference value of baPWV in healthy people classified by blood pressure and age,which may be valuable for the selection of baPWV test for people in different states of ages and blood pressure in health examination,and the preven-tion of arterial stiffness.

  17. Relationship between vascular endothelial function and pulse wave velocity in prehypertension

    Institute of Scientific and Technical Information of China (English)

    杨娉婷

    2014-01-01

    Objective To investigate the association between vascular endothelial function and arteriosclerosis in prehypertensive,hypertensive and healthy subjects.Methods 810 consecutive subjects were divided into three groups:hypertension group,prehypertension group and control group.Brachial-ankle pulse wave velocity(ba PWV)and flow-mediated brachial artery dilation(FMD)were used to evaluate the artery vascular stiffness and endothelial function respectively.Results Prehypertension

  18. Serum Calcium Level is Associated with Brachial-ankle Pulse Wave Velocity in Middle-aged and Elderly Chinese

    Institute of Scientific and Technical Information of China (English)

    DENG Xin Ru; BI Yu Fang; LU Jie Li; ZHANG Yin Fei; WANG Tian Ge; XU Bai Hui; SUN Ji Chao; ZHAO Lie Bin; XU Min; CHEN Yu Hong; WANG Wei Qing

    2014-01-01

    Objective To study the relation between serum calcium level and elevated BaPWV in Chinese subjects. Methods The relation between serum calcium level and elevated BaPWV was studied in 9 615 subjects. The mean value of left and right BaPWV was analyzed. BaPWV was defined as high when it was³1 752.5 cm/s (the upper quartile) either side. Results The BaPWV and its elevated percentage progressively increased across the quartiles of the serum calcium level (P Conclusion The elevated serum calcium level is related to an elevated BaPWV and a higher risk of arterial stiffness, independent of conventional risk factors, in middle-aged and elderly Chinese subjects.

  19. Relationship between resistant hypertension and arterial stiffness assessed by brachial-ankle pulse wave velocity in the older patient

    OpenAIRE

    Chung CM; Cheng HW; Chang JJ; Lin YS; Hsiao JF; Chang ST; Hsu JT

    2014-01-01

    Chang-Min Chung,1,2 Hui-Wen Cheng,2 Jung-Jung Chang,2 Yu-Sheng Lin,2 Ju-Feng Hsiao,2 Shih-Tai Chang,1 Jen-Te Hsu2,31School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, 2Division of Cardiology, Chang Gung Memorial Hospital, Chiayi, 3Department of Medicine, College of Medicine, Chang Gung University, Taoyuan County, TaiwanBackground: Resistant hypertension (RH) is a common clinical condition associated with increased cardiovascular mortality and morbidi...

  20. Relationship between resistant hypertension and arterial stiffness assessed by brachial-ankle pulse wave velocity in the older patient

    OpenAIRE

    Chung, Chang-Min

    2014-01-01

    Chang-Min Chung,1,2 Hui-Wen Cheng,2 Jung-Jung Chang,2 Yu-Sheng Lin,2 Ju-Feng Hsiao,2 Shih-Tai Chang,1 Jen-Te Hsu2,31School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, 2Division of Cardiology, Chang Gung Memorial Hospital, Chiayi, 3Department of Medicine, College of Medicine, Chang Gung University, Taoyuan County, TaiwanBackground: Resistant hypertension (RH) is a common clinical condition associated with increased cardiovascular mortality and...

  1. Validity and reproducibility of arterial pulse wave velocity measurement using new device with oscillometric technique: A pilot study

    Directory of Open Access Journals (Sweden)

    Patnaik Amar

    2005-08-01

    Full Text Available Abstract Background Availability of a range of techniques and devices allow measurement of many variables related to the stiffness of large or medium sized arteries. There is good evidence that, pulse wave velocity is a relatively simple measurement and is a good indicator of changes in arterial properties. The pulse wave velocity calculated from pulse wave recording by other methods like doppler or tonometry is tedious, time-consuming and above all their reproducibility depends on the operator skills. It requires intensive resource involvement. For epidemiological studies these methods are not suitable. The aim of our study was to clinically evaluate the validity and reproducibility of a new automatic device for measurement of pulse wave velocity that can be used in such studies. Methods In 44 subjects including normal healthy control and patients with coronary artery disease, heart brachial, heart ankle, brachial ankle and carotid femoral pulse wave velocities were recorded by using a new oscillometric device. Lead I and II electrocardiogram and pressure curves were simultaneously recorded. Two observers recorded the pulse wave velocity for validation and one observer recorded the velocity on two occasions for reproducibility. Results and Discussion Pulse wave velocity and arterial stiffness index were recorded in 24 control and 20 coronary artery disease patients. All the velocities were significantly high in coronary artery disease patients. There was highly significant correlation between the values noted by the two observers with low standard deviation. The Pearson's correlation coefficient for various velocities ranged from (r = 0.88–0.90 with (p Conclusion The new device "PeriScope" based on oscillometric technique has been found to be a simple, non-invasive and reproducible device for the assessment of pulse wave velocity and can be used to determine arterial stiffness in large population based studies.

  2. Risk factors associated with brachial–ankle pulse wave velocity among peritoneal dialysis patients in Macao

    Directory of Open Access Journals (Sweden)

    Kuang Ding-Wei

    2012-11-01

    Full Text Available Abstract Background Cardiovascular disease is the leading cause of mortality among peritoneal dialysis (PD patients in Macao. Increased arterial stiffness determined by pulse wave velocity (PWV has been established as an independent predictor of cardiovascular mortality in end-stage renal disease patients. The present study aims to investigate the relationship between arterial stiffness and its associated risk factors in chronic PD patients. Methods A total of 96 chronic PD patients (48 males/48 females were included in the cross-sectional study. Arterial stiffness was assessed by brachial-ankle PWV (baPWV. Patients were divided into two subgroups according to mean baPWV value. On enrollment, clinical characteristics and biochemical parameters were collected. Results Compared with low baPWV group patients, high baPWV group patients were significant older (pp=0.004 as well as previous CVD history (p=0.008. Serum albumin, pre-albumin levels and residual renal creatinine clearance (CCr were significantly lower but the serum ferritin level was significantly higher in high baPWV group patients than in low baPWV group patients (all pr=0.534, pr=0.350, pr=0.340, p=0.001. Meanwhile, baPWV negatively correlated with serum albumin (r=−0.479, pr=−0.320, p=0.003 and residual renal CCr (r=−0.177, p=0.048. Age-adjusted partial correlation test found a significant correlation between baPWV and CRP (r=0.462, ppp=0.015, CRP (p=0.019 and residual renal CCr (p=0.045. Conclusion Arterial stiffness, assessed by baPWV, had an independent correlation with age, serum albumin level, CRP level and residual renal CCr among PD patients in Macao.

  3. Is There an Association Between Carotid-Femoral Pulse Wave Velocity and Coronary Heart Disease in Patients with Coronary Artery Disease: A Pilot Study

    Science.gov (United States)

    Katsiki, Niki; Kollari, Erietta; Dardas, Sotirios; Dardas, Petros; Haidich, Anna-Bettina; Athyros, Vasilios G.; Karagiannis, Asterios

    2016-01-01

    Arterial stiffness has been shown to predict cardiovascular morbidity and mortality. Carotid-femoral pulse wave velocity (cfPWV) is regarded the gold standard marker of arterial stiffness. In previous studies, cfPWV was associated with the presence of coronary heart disease (CHD). However, with regard to CHD severity as assessed by the Syntax Score, only brachial-ankle PWV was reported to correlate with Syntax Score; no data exist for cfPWV. In this pilot study, we evaluated the possible associations between cfPWV, CHD and Syntax Score in 62 consecutive pa-tients (49 males; mean age: 64±12years) with chest pain undergoing scheduled coronary angiography. cfPWV was signifi-cantly higher in CHD patients than in non-CHD individuals (10 vs. 8.4 m/s; p = 0.003). No significant association was found between cfPWV and CHD severity as assessed by Syntax Score. A cut-off point of 12.3 m/s was considered as diagnostic for abnormally increased cfPWV (specificity: 97%; sensitivity: 12%; positive likelihood ratio: 3.558). Further research is needed to establish the relationship between cfPWV and Syntax Score. PMID:27347222

  4. Sequentially pulsed traveling wave accelerator

    Science.gov (United States)

    Caporaso, George J.; Nelson, Scott D.; Poole, Brian R.

    2009-08-18

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  5. Wave equations for pulse propagation

    International Nuclear Information System (INIS)

    Theoretical discussions of the propagation of pulses of laser radiation through atomic or molecular vapor rely on a number of traditional approximations for idealizing the radiation and the molecules, and for quantifying their mutual interaction by various equations of propagation (for the radiation) and excitation (for the molecules). In treating short-pulse phenomena it is essential to consider coherent excitation phenomena of the sort that is manifest in Rabi oscillations of atomic or molecular populations. Such processes are not adequately treated by rate equations for excitation nor by rate equations for radiation. As part of a more comprehensive treatment of the coupled equations that describe propagation of short pulses, this memo presents background discussion of the equations that describe the field. This memo discusses the origin, in Maxwell's equations, of the wave equation used in the description of pulse propagation. It notes the separation into lamellar and solenoidal (or longitudinal and transverse) and positive and negative frequency parts. It mentions the possibility of separating the polarization field into linear and nonlinear parts, in order to define a susceptibility or index of refraction and, from these, a phase and group velocity. The memo discusses various ways of characterizing the polarization characteristics of plane waves, that is, of parameterizing a transverse unit vector, such as the Jones vector, the Stokes vector, and the Poincare sphere. It discusses the connection between macroscopically defined quantities, such as the intensity or, more generally, the Stokes parameters, and microscopic field amplitudes. The material presented here is a portion of a more extensive treatment of propagation to be presented separately. The equations presented here have been described in various books and articles. They are collected here as a summary and review of theory needed when treating pulse propagation

  6. Jittering waves in rings of pulse oscillators.

    Science.gov (United States)

    Klinshov, Vladimir; Shchapin, Dmitry; Yanchuk, Serhiy; Nekorkin, Vladimir

    2016-07-01

    Rings of oscillators with delayed pulse coupling are studied analytically, numerically, and experimentally. The basic regimes observed in such rings are rotating waves with constant interspike intervals and phase lags between the neighbors. We show that these rotating waves may destabilize leading to the so-called jittering waves. For these regimes, the interspike intervals are no more equal but form a periodic sequence in time. Analytic criterion for the emergence of jittering waves is derived and confirmed by the numerical and experimental data. The obtained results contribute to the hypothesis that the multijitter instability is universal in systems with pulse coupling. PMID:27575122

  7. Quarter-wave pulse tube

    Science.gov (United States)

    Swift, G. W.; Gardner, D. L.; Backhaus, S. N.

    2011-10-01

    In high-power pulse-tube refrigerators, the pulse tube itself can be very long without too much dissipation of acoustic power on its walls. The pressure amplitude, the volume-flow-rate amplitude, and the time phase between them evolve significantly along a pulse tube that is about a quarter-wavelength long. Proper choice of length and area makes the oscillations at the ambient end of the long pulse tube optimal for driving a second, smaller pulse-tube refrigerator, thereby utilizing the acoustic power that would typically have been dissipated in the first pulse-tube refrigerator's orifice. Experiments show that little heat is carried from the ambient heat exchanger to the cold heat exchanger in such a long pulse tube, even though the oscillations are turbulent and even when the tube is compactly coiled.

  8. Pulse Wave Propagation in the Arterial Tree

    Science.gov (United States)

    van de Vosse, Frans N.; Stergiopulos, Nikos

    2011-01-01

    The beating heart creates blood pressure and flow pulsations that propagate as waves through the arterial tree that are reflected at transitions in arterial geometry and elasticity. Waves carry information about the matter in which they propagate. Therefore, modeling of arterial wave propagation extends our knowledge about the functioning of the cardiovascular system and provides a means to diagnose disorders and predict the outcome of medical interventions. In this review we focus on the physical and mathematical modeling of pulse wave propagation, based on general fluid dynamical principles. In addition we present potential applications in cardiovascular research and clinical practice. Models of short- and long-term adaptation of the arterial system and methods that deal with uncertainties in personalized model parameters and boundary conditions are briefly discussed, as they are believed to be major topics for further study and will boost the significance of arterial pulse wave modeling even more.

  9. Pulse Wave Velocity in the Carotid Artery

    DEFF Research Database (Denmark)

    Sørensen, Gertrud Laura; Jensen, Julie Brinck; Udesen, Jesper; Holfort, Iben Kraglund; Jensen, Jørgen Arendt

    The pulse wave velocity (PWV) in the carotid artery (CA) has been estimated based on ultrasound data collected by the experimental scanner RASMUS at DTU. Data is collected from one test subject using a frame rate (FR) of 4000 Hz. The influence of FRs is also investigated. The PWV is calculated from...... distension wave forms (DWF) estimated using cross-correlation. The obtained velocities give results in the area between 3-4 m/s, and the deviations between estimated PWV from two beats of a pulse are around 10%. The results indicate that the method presented is applicable for detecting the local PWV...

  10. Four-wave mixing with femtosecond pulses

    Energy Technology Data Exchange (ETDEWEB)

    Skenderovic, H [Institute of Physics, Bijenicka cesta 46, HR-10001 Zagreb (Croatia)], E-mail: hrvoje@ifs.hr

    2009-07-15

    The recent development of noncollinear optical parametric amplifiers (NOPAs) has equipped many laboratories with widely tunable, spectrally broad ultrashort laser pulses with a duration of 15-30 fs. The present work deals with sub-20 fs pulsed degenerate four wave mixing (DFWM) on high-frequency vibrational levels in all-trans-{beta}-carotene. The observed wavepacket motion on the electronic ground state revealed fast oscillating vibrational modes whose frequencies and time development were measured. The coherent control in an open loop is demonstrated by appropriate phase shaping of the pulses.

  11. Landau damping of a driven plasma wave from laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Bu Zhigang [Department of Physics, Shanghai University, Shanghai 200444 (China); Ji Peiyong [Department of Physics, Shanghai University, Shanghai 200444 (China); The Shanghai Key Lab of Astrophysics, Shanghai 200234 (China)

    2012-01-15

    The interaction between a laser pulse and a driven plasma wave with a phase velocity approaching the speed of light is studied, and our investigation is focused on the Gaussian laser pulse. It is demonstrated that when the resonance condition between the plasma wave and the laser pulse is satisfied, the Landau damping phenomenon of the plasma wave originated from the laser pulse will emerge. The dispersion relations for the plasma waves in resonance and non-resonance regions are obtained. It is proved that the Landau damping rate for a driven plasma wave is {gamma}>0 in the resonance region, so the laser pulse can produce an inverse damping effect, namely Landau growth effect, which leads an instability for the plasma wave. The Landau growth means that the energy is transmitted from the laser pulse to the plasma wave, which could be an effective process for enhancing the plasma wave.

  12. Pulse-wave morphology and pulse-wave velocity in healthy human volunteers

    DEFF Research Database (Denmark)

    Frimodt-Møller, M; Nielsen, A H; Kamper, A-L;

    2006-01-01

    OBJECTIVE: Applanation tonometry for pulse-wave analysis (PWA) and determination of pulse-wave velocity (PWV) is a non-invasive method for assessment of the central aortic pressure waveform and indices of arterial stiffness. The objective of this study was to examine the influence of eating and...... smoking on PWA and PWV measurements in order to establish standard examination conditions. Furthermore, intra- and interobserver reproducibility and the effects of varying the site of measurements were observed. MATERIAL AND METHODS: Duplicate measurements of the radial pressure waveform and of the...... smoking caused significant changes in both PWA and PWV parameters and an inter-arm difference was observed. Intra- and interobserver reproducibility was good. CONCLUSIONS: Pulse-wave measurements by applanation tonometry should be undertaken in the same arm during fasting and smoking abstinence....

  13. Reproducibility of Regional Pulse Wave Velocity in Healthy Subjects

    OpenAIRE

    Lee, Nak Bum; Park, Chang Gyu

    2009-01-01

    Background/Aims Despite the clinical importance and widespread use of pulse wave velocity (PWV), there are no standards for pulse sensors or for system requirements to ensure accurate pulse wave measurement. We assessed the reproducibility of PWV values using a newly developed PWV measurement system. Methods The system used in this study was the PP-1000, which simultaneously provides regional PWV values from arteries at four different sites (carotid, femoral, radial, and dorsalis pedis). Seve...

  14. BIOLOGICAL EFFECTS OF PULSED SHORT WAVE TREATMENT. AN EXPERIMENTAL STUDY

    OpenAIRE

    Dogaru Gabriela; Crăciun Constantin

    2015-01-01

    Pulsed short waves are short electromagnetic waves emitted as intermittent trains with a fixed duration, separated by free intervals of variable duration. The biological effects of pulsed short waves could be explained according to most of the authors by an activation of cellular enzymatic reactions, a stimulation of energy metabolism, a stimulation of liver function, of adrenal gland function and of the reticulocyte system, changes in cell permeability, by an increase of peripheral blood flo...

  15. Increasing pulse wave velocity in a realistic cardiovascular model does not increase pulse pressure with age

    OpenAIRE

    Mohiuddin, Mohammad W.; Rihani, Ryan J.; Laine, Glen A.; Quick, Christopher M.

    2012-01-01

    The mechanism of the well-documented increase in aortic pulse pressure (PP) with age is disputed. Investigators assuming a classical windkessel model believe that increases in PP arise from decreases in total arterial compliance (Ctot) and increases in total peripheral resistance (Rtot) with age. Investigators assuming a more sophisticated pulse transmission model believe PP rises because increases in pulse wave velocity (cph) make the reflected pressure wave arrive earlier, augmenting systol...

  16. Numerical continuation of travelling waves and pulses in neural fields

    OpenAIRE

    Meijer, Hil G.E.; Coombes, Stephen

    2013-01-01

    We study travelling waves and pulses in neural fields. Neural fields are a macroscopic description of the activity of brain tissue, which mathematically are formulated as integro-differential equations. While linear and weakly nonlinear analysis can describe instabilities and small amplitude patterns, numerical techniques are needed to study the nonlinear properties of travelling waves and pulses. Here we report on progress of such an approach using an excitatory neural field with linear adap...

  17. Accuracy of Arterial Pulse-Wave Velocity Measurement Using MR

    OpenAIRE

    Bolster, Bradley D.; Atalar, Ergin; Hardy, Christopher J.; McVeigh, Elliot R.

    1998-01-01

    The performance of a one-dimensional MR technique for the estimation of pulse-wave velocity in the aorta was evaluated. An expression for the error in this estimate was formulated and verified both by simulation and by experiment. On the basis of this formulation, guidelines for increasing the efficiency of the acquisition were established. The technique was further validated by comparison with pulse-wave velocity measurements made with a pressure catheter. All data were acquired from a latex...

  18. High-power pulse trains excited by modulated continuous waves

    OpenAIRE

    Wang, Yan; Song, Lijun; Li, Lu; Malomed, Boris A.

    2015-01-01

    Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demo...

  19. Traveling waves of the regularized short pulse equation

    International Nuclear Information System (INIS)

    The properties of the so-called regularized short pulse equation (RSPE) are explored with a particular focus on the traveling wave solutions of this model. We theoretically analyze and numerically evolve two sets of such solutions. First, using a fixed point iteration scheme, we numerically integrate the equation to find solitary waves. It is found that these solutions are well approximated by a finite sum of hyperbolic secants powers. The dependence of the soliton's parameters (height, width, etc) to the parameters of the equation is also investigated. Second, by developing a multiple scale reduction of the RSPE to the nonlinear Schrödinger equation, we are able to construct (both standing and traveling) envelope wave breather type solutions of the former, based on the solitary wave structures of the latter. Both the regular and the breathing traveling wave solutions identified are found to be robust and should thus be amenable to observations in the form of few optical cycle pulses. (paper)

  20. l-Citrulline supplementation attenuates blood pressure, wave reflection and arterial stiffness responses to metaboreflex and cold stress in overweight men.

    Science.gov (United States)

    Figueroa, Arturo; Alvarez-Alvarado, Stacey; Jaime, Salvador J; Kalfon, Roy

    2016-07-01

    Combined isometric exercise or metaboreflex activation (post-exercise muscle ischaemia (PEMI)) and cold pressor test (CPT) increase cardiac afterload, which may lead to adverse cardiovascular events. l-Citrulline supplementation (l-CIT) reduces systemic arterial stiffness (brachial-ankle pulse wave velocity (baPWV)) at rest and aortic haemodynamic responses to CPT. The aim of this study was to determine the effect of l-CIT on aortic haemodynamic and baPWV responses to PEMI+CPT. In all, sixteen healthy, overweight/obese males (age 24 (sem 6) years; BMI 29·3 (sem 4·0) kg/m2) were randomly assigned to placebo or l-CIT (6 g/d) for 14 d in a cross-over design. Brachial and aortic systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP), aortic augmented pressure (AP), augmentation index (AIx), baPWV, reflection timing (Tr) and heart rate (HR) were evaluated at rest and during isometric handgrip exercise (IHG), PEMI and PEMI+CPT at baseline and after 14 d. No significant effects were evident after l-CIT at rest. l-CIT attenuated the increases in aortic SBP and wave reflection (AP and AIx) during IHG, aortic DBP, MAP and AIx during PEMI, and aortic SBP, DBP, MAP, AP, AIx and baPWV during PEMI+CPT compared with placebo. HR and Tr were unaffected by l-CIT in all conditions. Our findings demonstrate that l-CIT attenuates aortic blood pressure and wave reflection responses to exercise-related metabolites. Moreover, l-CIT attenuates the exaggerated arterial stiffness response to combined metaboreflex activation and cold exposure, suggesting a protective effect against increased cardiac afterload during physical stress. PMID:27160957

  1. Effect of various pulse wave forms for pulse-type magnetic flux pump

    Science.gov (United States)

    Bai, Zhiming; Chen, Chuan; Wu, Yanqing; Zhen, Zhen

    2011-09-01

    The excitation current of magnetic pole windings in magnetic flux pump needs to be generated by a control system. In this paper, the control system of pulse-type high temperature superconducting magnetic flux pump is discussed in detail. The control system consists of a control circuit and a drive circuit. A direct current power supply is the unique power supply of the drive circuit. The control circuit is powered by a computer through a USB interface of the computer. The control circuit receives commands from the computer and controls the drive circuit to generate different pulse waves. Each pulse wave generates a unique pulse-type traveling magnetic field and will pump magnetic flux into the superconducting loop. Experiments have been performed to examine the pumping effect of different pulse waves on both MgB 2 and Bi-2223 superconducting loops using the proposed control system, and the best pulse wave has been found. The experimental results show that the magnetic flux pump can compensate current decay up to 32.5 A for MgB 2 loop and 129 A for Bi-2223 loop. It indicates that the control system of the pulse-type magnetic flux pump is effective and feasible.

  2. Pulse to CW conversion via four-wave mixing

    International Nuclear Information System (INIS)

    In addition to the evident advantages of optical phase conjugation, degenerate four-wave mixing also appears as a good candidate for applications in optical communications. It has already been suggested that this process be used for optical signal processing, the realization of mathematical operations such as convolution or correlation or the construction of logical gates as well as bistable components represent some other possible applications. The authors propose another application of degenerate four-wave mixing which is based on pulse reshaping at high pump intensity l/sub p/. It consists of the transformation of a pulse beam into a cw beam. They theoretically investigated the interaction between two constant pump beams and an incident pulse probe in a lossless Kerrlike medium. Under the small-signal approximation, it is known that the reflected pulse can be expressed as the convolution of the incident pulse with the impulse response of the phase conjugate mirror. In the low-efficiency regime, a pulsed incident beam then produces a pulsed reflected beam. In the nonlinear regime, however, the behavior is quite different. Above a critical pump intensity, the reflection is constant and does not depend on the nature of the incident pulse. This can be interpreted as a result of self-oscillations. They present the results of a numerical simulation of the phenomenon showing the transient behavior. The analysis includes pump depletion and nonlinear phase modulation effects. They also investigate the influence of a finite response time of the Kerr medium

  3. Wave packet dynamics under effect of a pulsed electric field

    Science.gov (United States)

    da Silva, A. R. C. B.; de Moura, F. A. B. F.; Dias, W. S.

    2016-06-01

    We studied the dynamics of an electron in a crystalline one-dimensional model under effect of a time-dependent Gaussian field. The time evolution of an initially Gaussian wave packet it was obtained through the numerical solution of the time-dependent Schrödinger equation. Our analysis consists of computing the electronic centroid as well as the mean square displacement. We observe that the electrical pulse is able to promote a special kind of displacement along the chain. We demonstrated a direct relation between the group velocity of the wave packet and the applied electrical pulses. We compare those numerical calculations with a semi-classical approach.

  4. Calcium waves induced by large voltage pulses in fish keratocytes.

    OpenAIRE

    Brust-Mascher, I; Webb, W W

    1998-01-01

    Intracellular calcium waves in fish keratocytes are induced by the application of electric field pulses with amplitudes between 55 and 120 V/cm and full width at half-maximum of 65-100 ms. Calcium concentrations were imaged using two-photon excited fluorescence microscopy (Denk et al., 1990 Science. 248:73-76; Williams et al. 1994 FASEB J. 8:804-813) and the ratiometric calcium indicator indo-1. The applied electric field pulses induced waves with fast calcium rise times and slow decays, whic...

  5. High-power pulse trains excited by modulated continuous waves

    CERN Document Server

    Wang, Yan; Li, Lu; Malomed, Boris A

    2015-01-01

    Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demonstrated that the double trains propagate in a robust form, with frequencies shifted by the Raman effect.

  6. Cardioaccelerometery: the assessment of pulse wave velocity using accelerometers

    OpenAIRE

    Pereira, Helena Catarina de Bastos Marques

    2007-01-01

    In the past recent years, great emphasis has been placed on the role of arterial stiffness in the development of cardiovascular diseases, recognized as the leading cause of death in the world. This hemodynamic parameter, generally associated to age and blood pressure increase, can be assessed by the measurement of the pulse wave velocity (PWV), i.e., the velocity at which the pressure wave propagates along an artery. Although PWV measurement is accepted as the most simple, non-...

  7. Thermally driven continuous-wave and pulsed optical vortex

    CERN Document Server

    Ding, Yitian; Zhao, Yongguang; Yu, Haohai; Zhang, Huaijin; Wang, Zhengping; Wang, Jiyang

    2013-01-01

    We demonstrated the continuous-wave (cw) and pulsed optical vortex with topological charges driven by heat generated during the lasing process without introducing the astigmatism effect and reducing lasing efficiency. During the lasing process, the topological charges were changeable by the thermal-induced lens and selected by the mode-matching between the pump and oscillating beams. With a graphene sample as the saturable absorber, the pulsed optical vortex was achieved at the wavelength of 1.36 {\\mu}m, which identified that graphene could be used as a pulse modulator for the generation of pulsed optical vortex. It could be believed that the thermally driven cw and pulsed optical vortex should have various promising applications based on the compact structure, changeable topological charges and specific wavelength

  8. Pulse wave velocity measured by Multichannel whole body impedance plethysmograph

    Czech Academy of Sciences Publication Activity Database

    Viščor, Ivo; Jurák, Pavel; Plešinger, Filip; Vondra, Vlastimil; Halámek, Josef; Soukup, L.; Matějková, M.

    Brno : Society for Medical Innovation and Technology, 2015. s. 70. [SMIT 2015. International Conference of the Society for Medical Innovation and Technology/27./. 10.09.2015-12.09.2015, Brno] Institutional support: RVO:68081731 Keywords : electrical impedance * plethysmograph * pulse wave velocity * arterial stiffness Subject RIV: BH - Optics, Masers, Lasers

  9. Limited Diffraction Maps for Pulsed Wave Annular Arrays

    DEFF Research Database (Denmark)

    Fox, Paul D.

    2002-01-01

    A procedure is provided for decomposing the linear field of flat pulsed wave annular arrays into an equivalent set of known limited diffraction Bessel beams. Each Bessel beam propagates with known characteristics, enabling good insight into the propagation of annular fields to be obtained...

  10. Non-invasive measurement of local pulse pressure by pulse wave-based ultrasound manometry (PWUM)

    OpenAIRE

    Vappou, J.; Luo, J; Okajima, K.; Di Tullio, M; Konofagou, E E

    2011-01-01

    The central Blood Pressure (CBP) has been established as a relevant indicator of cardiovascular disease. Despite its significance, CBP remains particularly challenging to measure in standard clinical practice. The objective of this study is to introduce Pulse Wave-based Ultrasound Manometry (PWUM) as a simple-touse, non-invasive ultrasound-based method for quantitative measurement of the central pulse pressure. Arterial wall displacements are estimated using radiofrequency (RF) ultrasound sig...

  11. Wave fronts, pulses and wave trains in photoexcited superlattices behaving as excitable or oscillatory media

    International Nuclear Information System (INIS)

    Undoped and strongly photoexcited semiconductor superlattices with field-dependent recombination behave as excitable or oscillatory media with spatially discrete nonlinear convection and diffusion. Infinitely long, dc-current-biased superlattices behaving as excitable media exhibit wave fronts with increasing or decreasing profiles, whose velocities can be calculated by means of asymptotic methods. These superlattices can also support pulses of the electric field. Pulses moving downstream with the flux of electrons can be constructed from their component wave fronts, whereas pulses advancing upstream do so slowly and experience saltatory motion: they change slowly in long intervals of time separated by fast transitions during which the pulses jump to the previous superlattice period. Photoexcited superlattices can also behave as oscillatory media and exhibit wave trains. (paper)

  12. Toroidal Imploding Detonation Wave Initiator for Pulse Detonation Engines

    OpenAIRE

    Jackson, S. I.; Shepherd, J. E.

    2007-01-01

    Imploding toroidal detonation waves were used to initiate detonations in propane–air and ethylene–air mixtures inside of a tube. The imploding wave was generated by an initiator consisting of an array of channels filled with acetylene–oxygen gas and ignited with a single spark. The initiator was designed as a low-drag initiator tube for use with pulse detonation engines. To detonate hydrocarbon–air mixtures, the initiator was overfilled so that some acetylene oxygen spilled into the tube. The...

  13. Wave fronts, pulses and wave trains in photoexcited superlattices behaving as excitable or oscillatory media

    OpenAIRE

    Arana, J. I.; Bonilla, L. L.; Grahn, H. T.

    2011-01-01

    Undoped and strongly photoexcited semiconductor superlattices with field-dependent recombination behave as excitable or oscillatory media with spatially discrete nonlinear convection and diffusion. Infinitely long, dc-current-biased superlattices behaving as excitable media exhibit wave fronts with increasing or decreasing profiles, whose velocities can be calculated by means of asymptotic methods. These superlattices can also support pulses of the electric field. Pulses moving downstream wit...

  14. Femtosecond-pulse-train ionization of Rydberg wave packets

    OpenAIRE

    Simonsen, Sigrid Ina; Sørngård, Stian Astad; Førre, Morten; Hansen, Jan Petter

    2012-01-01

    We calculate, based on first-order perturbation theory, the total and differential ionization probabilities from a dynamic periodic Rydberg wave packet of a given n-shell exposed to a train of femtosecond laser pulses. The total probability is shown to depend crucially on the laser repetition rate: For certain frequencies the ionization probability vanishes, while for others it becomes very large. The origin of this effect is the strong dependence of the ionization probability on ...

  15. Non-invasive measurement of local pulse pressure by pulse wave-based ultrasound manometry (PWUM)

    International Nuclear Information System (INIS)

    Central blood pressure (CBP) has been established as a relevant indicator of cardiovascular disease. Despite its significance, CBP remains particularly challenging to measure in standard clinical practice. The objective of this study is to introduce pulse wave-based ultrasound manometry (PWUM) as a simple-to-use, non-invasive ultrasound-based method for quantitative measurement of the central pulse pressure. Arterial wall displacements are estimated using radiofrequency ultrasound signals acquired at high frame rates and the pulse pressure waveform is estimated using both the distension waveform and the local pulse wave velocity. The method was tested on the abdominal aorta of 11 healthy subjects (age 35.7±16 y.o.). PWUM pulse pressure measurements were compared to those obtained by radial applanation tonometry using a commercial system. The average intra-subject variability of the pulse pressure amplitude was found to be equal to 4.2 mmHg, demonstrating good reproducibility of the method. Excellent correlation was found between the waveforms obtained by PWUM and those obtained by tonometry in all subjects (0.94 < r < 0.98). A significant bias of 4.7 mmHg was found between PWUM and tonometry. PWUM is a highly translational method that can be easily integrated in clinical ultrasound imaging systems. It provides an estimate of the pulse pressure waveform at the imaged location, and may offer therefore the possibility to estimate the pulse pressure at different arterial sites. Future developments include the validation of the method against invasive estimates on patients, as well as its application to other large arteries

  16. A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

    International Nuclear Information System (INIS)

    We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2∼1.0μW in the Human heart rate range on the skin contact area of 3.71cm2. Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves

  17. Laser-supported detonation waves and pulsed laser propulsion

    International Nuclear Information System (INIS)

    A laser thermal rocket uses the energy of a large remote laser, possibly ground-based, to heat an inert propellant and generate thrust. Use of a pulsed laser allows the design of extremely simple thrusters with very high performance compared to chemical rockets. The temperatures, pressures, and fluxes involved in such thrusters (104 K, 102 atmospheres, 107 w/cm2) typically result in the creation of laser-supported detonation (LSD) waves. The thrust cycle thus involves a complex set of transient shock phenomena, including laser-surface interactions in the ignition of the LSD wave, laser-plasma interactions in the LSD wave itself, and high-temperature nonequilibrium chemistry behind the LSD wave. The SDIO Laser Propulsion Program is investigating these phenomena as part of an overall effort to develop the technology for a low-cost Earth-to-orbit laser launch system. We will summarize the Program's approach to developing a high performance thruster, the double-pulse planar thruster, and present an overview of some results obtained to date, along with a discussion of the many research question still outstanding in this area

  18. Increasing pulse wave velocity in a realistic cardiovascular model does not increase pulse pressure with age.

    Science.gov (United States)

    Mohiuddin, Mohammad W; Rihani, Ryan J; Laine, Glen A; Quick, Christopher M

    2012-07-01

    The mechanism of the well-documented increase in aortic pulse pressure (PP) with age is disputed. Investigators assuming a classical windkessel model believe that increases in PP arise from decreases in total arterial compliance (C(tot)) and increases in total peripheral resistance (R(tot)) with age. Investigators assuming a more sophisticated pulse transmission model believe PP rises because increases in pulse wave velocity (c(ph)) make the reflected pressure wave arrive earlier, augmenting systolic pressure. It has recently been shown, however, that increases in c(ph) do not have a commensurate effect on the timing of the reflected wave. We therefore used a validated, large-scale, human arterial system model that includes realistic pulse wave transmission to determine whether increases in c(ph) cause increased PP with age. First, we made the realistic arterial system model age dependent by altering cardiac output (CO), R(tot), C(tot), and c(ph) to mimic the reported changes in these parameters from age 30 to 70. Then, c(ph) was theoretically maintained constant, while C(tot), R(tot), and CO were altered. The predicted increase in PP with age was similar to the observed increase in PP. In a complementary approach, C(tot), R(tot), and CO were theoretically maintained constant, and c(ph) was increased. The predicted increase in PP was negligible. We found that increases in c(ph) have a limited effect on the timing of the reflected wave but cause the system to degenerate into a windkessel. Changes in PP can therefore be attributed to a decrease in C(tot). PMID:22561301

  19. Noninvasive continuous monitoring of digital pulse waves during hemodialysis

    DEFF Research Database (Denmark)

    Burkert, Antje; Scholze, Alexandra; Tepel, Martin

    2009-01-01

    Intermittent hemodynamic instability during hemodialysis treatment is a frequent complication in patients with end-stage renal failure. A noninvasive method for continuous hemodynamic monitoring is needed. We used noninvasive digital photoplethysmography and an algorithm for continuous, investiga......Intermittent hemodynamic instability during hemodialysis treatment is a frequent complication in patients with end-stage renal failure. A noninvasive method for continuous hemodynamic monitoring is needed. We used noninvasive digital photoplethysmography and an algorithm for continuous......, investigator-independent, automatic analysis of digital volume pulse in 10 healthy subjects and in 20 patients with end-stage renal failure during the hemodialysis session. The reflective index was defined representing the diastolic component of the digital pulse wave. The properties of the reflective index...... were studied in healthy control subjects (n=10). An increased reflective index was due to increased peripheral pulse wave reflection (e.g., vasoconstriction). During a hemodialysis session, the reflective index increased significantly from 36+/-3 arbitrary units to 41+/-3 arbitrary units (n=20; p...

  20. BIOLOGICAL EFFECTS OF PULSED SHORT WAVE TREATMENT. AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    Dogaru Gabriela

    2015-02-01

    Full Text Available Pulsed short waves are short electromagnetic waves emitted as intermittent trains with a fixed duration, separated by free intervals of variable duration. The biological effects of pulsed short waves could be explained according to most of the authors by an activation of cellular enzymatic reactions, a stimulation of energy metabolism, a stimulation of liver function, of adrenal gland function and of the reticulocyte system, changes in cell permeability, by an increase of peripheral blood flow through the enhancement of local vascularization. This research aimed to investigate the biological effects of exposure to pulsed short waves at different doses on the adrenal glands of experimental animals, by structural and ultrastructural studies. The study included 35 animals assigned to 4 groups. Group I included 10 experimental animals exposed to radiation at a dose of 1/80 impulses/sec, group II, 10 animals exposed to a dose of 4/400 impulses/sec, group III, 10 animals exposed to a dose of 6/600 impulses/sec, for 10 min/day, and the control group consisted of 5 unexposed animals. Structural and ultrastructural changes of adrenal glands induced by the dose of 4/400 impulses/sec, compared to the unexposed control group and the dose of 1/80 impulses/sec, include an intensification of protein synthesis processes, an enhancement of energy metabolism in providing the energy required for an increased production of hormones, an intensification of collagen fiber synthesis processes in the capsule, necessary for healing. It was demonstrated that this dose induced an intensification of hormone synthesis and secretion, a stimulation of adrenal function. At the dose of 6/600 cycles/sec, a slight diminution of hormone synthesis and secretion activity was found, which was not below the limits existing in the unexposed control group, but was comparable to group II. This dose is probably too strong for experimental animals, inducing them a state of stress. The

  1. RELATIONS BETWEEN DAIRY FOOD INTAKE AND ARTERIAL STIFFNESS: PULSE WAVE VELOCITY AND PULSE PRESSURE

    OpenAIRE

    Crichton, Georgina E; Elias, Merrrill F.; Dore, Gregory A.; Abhayaratna, Walter P.; Robbins, Michael A.

    2012-01-01

    Modifiable risk factors, such as diet, are becomingly increasingly important in the management of cardiovascular disease, one of the greatest major causes of death and disease burden. Few studies have examined the role of diet as a possible means of reducing arterial stiffness, as measured by pulse wave velocity, an independent predictor of cardiovascular events and all-cause mortality. The aim of this study was to investigate whether dairy food intake is associated with measures of arterial ...

  2. Optimization of arterial age prediction models based in pulse wave

    International Nuclear Information System (INIS)

    We propose the detection of early arterial ageing through a prediction model of arterial age based in the coherence assumption between the pulse wave morphology and the patient's chronological age. Whereas we evaluate several methods, a Sugeno fuzzy inference system is selected. Models optimization is approached using hybrid methods: parameter adaptation with Artificial Neural Networks and Genetic Algorithms. Features selection was performed according with their projection on main factors of the Principal Components Analysis. The model performance was tested using the bootstrap error type .632E. The model presented an error smaller than 8.5%. This result encourages including this process as a diagnosis module into the device for pulse analysis that has been developed by the Bioengineering Laboratory staff

  3. Pulse wave analysis with two tonometric devices: a comparison study

    International Nuclear Information System (INIS)

    Pulse wave analysis is a pivotal tool to estimate central haemodynamic parameters. Available commercial devices use applanation tonometry and have been validated against invasive catheterism. We previously observed differences on a radial second systolic peak (rSPB2) between two commonly used devices: SphygmoCor (AtCor, Australia) and PulsePen (DiaTecne, Italy). The aim of our study was to further quantify differences in radial and carotid signals from the two devices.We measured radial and carotid waveforms in 38 patients with minimal changes between systolic, diastolic blood pressure and heart rate. rSBP2, mean pressure, form factor and augmentation index were different with SphygmoCor providing lower values (mean differences: 2.2 ± 3.8 mmHg; 1.5 ± 1.7 mmHg; 3.2 ± 3.5%; 4.2 ± 8.4%, respectively). Carotid augmentation index and form factor were similar. However carotid systolic pressure (cSBP) from PulsePen was higher than cSBP from SphygmoCor (2.7 ± 4.4 mmHg, p < 0.001). For both carotid and radial signals, harmonics moduli were similar across the spectrum with the exception of the 1st harmonic. PulsePen and SphygmoCor sensors are not equivalent and provide different wave shapes despite similar harmonics content with more discrepancy on radial derived parameters than on carotid derived parameters. Further studies are required to compare invasive pressure parameters to indices derived from these two devices. (paper)

  4. Estimation of Carotid Artery Pulse Wave Velocity by Doppler Ultrasonography

    OpenAIRE

    Mehdi Maerefat; Manijhe Mokhtari Dizaji; Saeed Rahgozar

    2009-01-01

    Background: Pulse wave velocity (PWV) is widely used for estimating the stiffness of an artery. Various invasive and non-invasive methods have been developed to determine PWV over the years. In the present research, the non-invasive estimation of the PWV of large arteries was used as an index for arterial stiffness. Methods: A dynamic model based on the Navier-Stokes equations coupled to elasticity equations was introduced for the PWV in arteries with elastic walls. This system of equations w...

  5. Weight Loss, Dietary Intake and Pulse Wave Velocity

    OpenAIRE

    Petersen, Kristina; Blanch, Natalie; Keogh, Jennifer; Clifton, Peter

    2015-01-01

    We have recently conducted a meta-analysis to determine the effect of weight loss achieved by an energy-restricted diet with or without exercise, anti-obesity drugs or bariatric surgery on pulse wave velocity (PWV) measured at all arterial segments. Twenty studies, including 1,259 participants, showed that modest weight loss (8% of the initial body weight) caused a reduction in PWV measured at all arterial segments. However, due to the poor methodological design of the included studies, the r...

  6. Three-wave mixing mediated femtosecond pulse compression in β-barium borate.

    Science.gov (United States)

    Grün, A; Austin, Dane R; Cousin, Seth L; Biegert, J

    2015-10-15

    Nonlinear pulse compression mediated by three-wave mixing is demonstrated for ultrashort Ti:sapphire pulses in a type II phase-matched β-barium borate (BBO) crystal using noncollinear geometry. 170 μJ pulses at 800 nm with a pulse duration of 74 fs are compressed at their sum frequency to 32 fs with 55 μJ of pulse energy. Experiments and computer simulations demonstrate the potential of sum-frequency pulse compression to match the group velocities of the interacting waves to crystals that were initially not considered in the context of nonlinear pulse compression. PMID:26469593

  7. Detailed Characterization of Continuous-Wave and Pulsed-Pump Four-Wave Mixing in Nonlinear Fibers

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Galili, Michael; Grüner-Nielsen, Lars;

    2016-01-01

    We explore the parametric gain differences for continuous-wave and pulse-pumped four-wave mixing, using various highly nonlinear fibers. Detailed simulations support our findings that the dispersion slope determines the experimentally observed differences, limiting the pulsed-pump performance....

  8. Quantum-state-preserving optical frequency conversion and pulse reshaping by four-wave mixing

    DEFF Research Database (Denmark)

    McKinstrie, C. J.; Andersen, Lasse Mejling; Raymer, M. G.;

    2012-01-01

    Nondegenerate four-wave mixing driven by two pulsed pumps transfers the quantum state of an input signal pulse to an output idler pulse, which is a frequency-converted and reshaped version of the signal. By varying the pump shapes appropriately, one can connect signal and idler pulses with...

  9. Full-wave reflection of lightning long-wave radio pulses from the ionospheric D- region

    Science.gov (United States)

    Jacobson, A. R.; Shao, X.; Holzworth, R.

    2008-12-01

    A model is developed for calculating ionospheric reflection of electromagnetic pulses emitted by lightning, with most energy in the long-wave spectral region (f = 3 - 100 kHz). The building-block of the calculation is a differential-equation full-wave solution of Maxwell's Equations for the complex reflection of individual plane waves incident from below, by the anisotropic, dissipative, diffuse dielectric profile of the lower ionosphere. This full-wave solution is then put into a summation over plane waves in an angular Direct Fourier Transform to obtain the reflection properties of curved wavefronts. This step models also the diffraction effects of long- wave ionospheric reflections observed at short or medium range (200 - 500 km). The calculation can be done with any arbitrary but smooth dielectric profile versus altitude. For an initial test, we use the classic D- region exponential profiles of electron density and collision rate given by Wait. With even these simple profiles, our model of full-wave reflection of curved wavefronts captures some of the basic attributes of observed reflected waveforms recorded with the Los Alamos Sferic Array.

  10. [Research on a non-invasive pulse wave detection and analysis system].

    Science.gov (United States)

    Li, Ting; Yu, Gang

    2008-10-01

    A novel non-invasive pulse wave detection and analysis system has been developed, including the software and the hardware. Bi-channel signals can be acquired, stored and shown on the screen dynamically at the same time. Pulse wave can be reshown and printed after pulse wave analysis and pulse wave velocity analysis. This system embraces a computer which is designed for fast data saving, analyzing and processing, and a portable data sampling machine which is based on a singlechip. Experimental results have shown that the system is stable and easy to use, and the parameters are calculated accurately. PMID:19024446

  11. A new estimate method of micro-pulse width using standing wave measurement

    International Nuclear Information System (INIS)

    A new method for estimating the micro-pulse width of electron beam using the measurement of the standing wave distribution is discussed. When a conducting plate is set transversely in the vicinity to an electron beam's path, the standing wave distribution is formed by interference between two waves. One is an incident wave radiated directly from electron beam. Another is a reflected wave returned from the conducting plate. Further the wave radiated from the edge of plate exists. This radiated wave propagates spherically and affects the above standing wave distribution. We measured the standing wave distributions by using Hokkaido University 45 MeV Linac. The micro-pulse width was estimated by using this new method, i.e. using the ratio and width of each dip of the standing wave distribution. The estimated values showed well agreement with the expected pulse width of this linac. (author)

  12. Bit rate and pulse width dependence of four-wave mixing of short optical pulses in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Diez, S.; Mecozzi, A.; Mørk, Jesper

    1999-01-01

    We investigate the saturation properties of four-wave mixing of short optical pulses in a semiconductor optical amplifier. By varying the gain of the optical amplifier, we find a strong dependence of both conversion efficiency and signal-to-background ratio on pulse width and bit rate. In...

  13. Temporal pattern of pulse wave velocity during brachial hyperemia reactivity

    International Nuclear Information System (INIS)

    Endothelial function can be assessed non-invasively with ultrasound, analyzing the change of brachial diameter in response to transient forearm ischemia. We propose a new technique based in the same principle, but analyzing a continuous recording of carotid-radial pulse wave velocity (PWV) instead of diameter. PWV was measured on 10 healthy subjects of 22±2 years before and after 5 minutes forearm occlusion. After 59 ± 31 seconds of cuff release PWV decreased 21 ± 9% compared to baseline, reestablishing the same after 533 ± 65 seconds. There were no significant changes observed in blood pressure. When repeating the study one hour later in 5 subjects, we obtained a coefficient of repeatability of 4.8%. In conclusion, through analysis of beat to beat carotid-radial PWV it was possible to characterize the temporal profiles and analyze the acute changes in response to a reactive hyperemia. The results show that the technique has a high sensitivity and repeatability.

  14. Temporal pattern of pulse wave velocity during brachial hyperemia reactivity

    Science.gov (United States)

    Graf, S.; Valero, M. J.; Craiem, D.; Torrado, J.; Farro, I.; Zócalo, Y.; Valls, G.; Bía, D.; Armentano, R. L.

    2011-09-01

    Endothelial function can be assessed non-invasively with ultrasound, analyzing the change of brachial diameter in response to transient forearm ischemia. We propose a new technique based in the same principle, but analyzing a continuous recording of carotid-radial pulse wave velocity (PWV) instead of diameter. PWV was measured on 10 healthy subjects of 22±2 years before and after 5 minutes forearm occlusion. After 59 ± 31 seconds of cuff release PWV decreased 21 ± 9% compared to baseline, reestablishing the same after 533 ± 65 seconds. There were no significant changes observed in blood pressure. When repeating the study one hour later in 5 subjects, we obtained a coefficient of repeatability of 4.8%. In conclusion, through analysis of beat to beat carotid-radial PWV it was possible to characterize the temporal profiles and analyze the acute changes in response to a reactive hyperemia. The results show that the technique has a high sensitivity and repeatability.

  15. Pulse wave velocity predicts mortality in renal transplant patients

    Directory of Open Access Journals (Sweden)

    Mitchell A

    2010-10-01

    Full Text Available Abstract Background Measuring arterial stiffness using pulse wave velocity (PWV has become an important tool to assess vascular function and cardiovascular mortality. For subject with hypertension, end-stage renal disease and diabetes, PWV has been shown to predict cardiovascular and all-cause mortality. We hypothesize that PWV would also predict mortality in subjects who have undergone kidney transplantation. Methods A cohort of 330 patients with renal transplantation was studied with a mean age at entry 51.4 ± 0.75 years. Mean follow-up was 3.8 years (± 0.7 years; 16 deaths occurred during follow-up. At entry, together with standard clinical and biochemical parameters, PWV was determined from pressure tracing over carotid and femoral arteries. Results With increasing PWV, there was a significant increase in age, systolic blood pressure and pulse pressure. In addition, subjects with higher PWV also exhibited more frequently the presence of coronary heart disease. On the basis of Cox analyses, PWV and systolic blood pressure emerged as predictors of all-cause mortality. Conclusion These results provide evidence that PWV is a strong predictor of all-cause mortality in the population of renal transplant recipients.

  16. Application of wave-shape functions and Synchrosqueezing transform to pulse signal analysis

    CERN Document Server

    Wu, Hau-tieng; Wu, Han-Kuei; Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang

    2015-01-01

    We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and study the pulse wave signal. Based on the wave shape function model and SST, we extract features, called the spectral pulse signature, based on the functional regression technique, to characterize the hemodynamics from the pulse wave signals. To demonstrate how the algorithm and the extracted features work, we study the radial pulse wave signal recorded by the sphygmomanometer from normal subjects and patients with congestive heart failure. The analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features. In addition, it shows that different positions of the radial artery contain significant different information, which is compatible with the empirical conclusion of the pulse diagnosis in the traditional Chinese medicine.

  17. Noninvasive measurement of cardiac stroke volume using pulse wave velocity and aortic dimensions: a simulation study

    OpenAIRE

    Charles F. Babbs

    2014-01-01

    Background: Concerns about the cost-effectiveness of invasive hemodynamic monitoring in critically ill patients using pulmonary artery catheters motivate a renewed search for effective noninvasive methods to measure stroke volume. This paper explores a new approach based on noninvasively measured pulse wave velocity, pulse contour, and ultrasonically determined aortic cross sectional area. Methods: The Bramwell-Hill equation relating pulse wave velocity to aortic compliance is applied. At the...

  18. Pulse compression by nonlinear pulse evolution with reduced optical wave breaking in erbium-doped fiber amplifiers.

    Science.gov (United States)

    Tamura, K; Nakazawa, M

    1996-01-01

    Nonlinear pulse evolution is studied for a fiber with normal dispersion (ND) and gain. Numerical simulations show that under certain conditions the pulse evolves into a parabolic shape, which has been shown to reduce optical wave breaking. Much as with the square pulse that forms in passive fibers with ND, the interplay of ND and self-phase modulation creates a highly linear chirp, which can be efficiently compressed. Application to an amplifying fiber/grating (prism) pair pulse compressor is considered, with an experimental demonstration of compression from 350 to 77 fs at a gain of 18 dB in an erbium-doped fiber amplifier. PMID:19865307

  19. Wave-breaking-extended fiber supercontinuum generation for high compression ratio transform-limited pulse compression.

    Science.gov (United States)

    Liu, Yuan; Tu, Haohua; Boppart, Stephen A

    2012-06-15

    Wave-breaking often occurs when a short intense optical pulse propagates in a long normally dispersive optical fiber. This effect has conventionally been avoided in fiber (super-)continuum-based pulse compression because the accumulated frequency chirp of the output pulse cannot be fully compensated by a standard prism (or grating) pair. Thus, the spectral extending capability of the wave-breaking has not been utilized to shorten the compressed pulse. We demonstrate that wave-breaking-free operation is not necessary if a 4f pulse shaper-based compressor is employed to remove both the linear and nonlinear chirp of the output pulse. By propagating a 180 fs (FWHM) input pulse in a nonlinear photonic crystal fiber beyond the wave-breaking limit, we compress the wave-breaking-extended supercontinuum output pulse to the bandwidth-limited duration of 6.4 fs (FWHM). The combination of high compression ratio (28×) and short pulse width represents a significant improvement over that attained in the wave-breaking-free regime. PMID:22739845

  20. Pulse Wave Variation during the Menstrual Cycle in Women with Menstrual Pain.

    Science.gov (United States)

    Jeon, Soo Hyung; Kim, Kyu Kon; Lee, In Seon; Lee, Yong Tae; Kim, Gyeong Cheol; Chi, Gyoo Yong; Cho, Hye Sook; Kang, Hee Jung; Kim, Jong Won

    2016-01-01

    Objective. This study is performed to obtain objective diagnostic indicators associated with menstrual pain using pulse wave analysis. Methods. Using a pulse diagnostic device, we measured the pulse waves of 541 women aged between 19 and 30 years, placed in either an experimental group with menstrual pain (n = 329) or a control group with little or no menstrual pain (n = 212). Measurements were taken during both the menstrual and nonmenstrual periods, and comparative analysis was performed. Results. During the nonmenstrual period, the experimental group showed a significantly higher value in the left radial artery for the radial augmentation index (RAI) (p = 0.050) but significantly lower values for pulse wave energy (p = 0.021) and time to first peak from baseline (T1) (p = 0.035) in the right radial artery. During the menstrual period, the experimental group showed significantly lower values in the left radial artery for cardiac diastole and pulse wave area during diastole and significantly higher values for pulse wave area during systole, ratio of systolic phase to the full heartbeat, and systolic-diastolic ratio. Conclusion. We obtained indicators of menstrual pain in women during the menstrual period, including prolonged systolic and shortened diastolic phases, increases in pulse wave energy and area of representative pulse wave, and increased blood vessel resistance. PMID:27579304

  1. Pulse Wave Variation during the Menstrual Cycle in Women with Menstrual Pain

    Directory of Open Access Journals (Sweden)

    Soo Hyung Jeon

    2016-01-01

    Full Text Available Objective. This study is performed to obtain objective diagnostic indicators associated with menstrual pain using pulse wave analysis. Methods. Using a pulse diagnostic device, we measured the pulse waves of 541 women aged between 19 and 30 years, placed in either an experimental group with menstrual pain (n=329 or a control group with little or no menstrual pain (n=212. Measurements were taken during both the menstrual and nonmenstrual periods, and comparative analysis was performed. Results. During the nonmenstrual period, the experimental group showed a significantly higher value in the left radial artery for the radial augmentation index (RAI (p=0.050 but significantly lower values for pulse wave energy (p=0.021 and time to first peak from baseline (T1 (p=0.035 in the right radial artery. During the menstrual period, the experimental group showed significantly lower values in the left radial artery for cardiac diastole and pulse wave area during diastole and significantly higher values for pulse wave area during systole, ratio of systolic phase to the full heartbeat, and systolic-diastolic ratio. Conclusion. We obtained indicators of menstrual pain in women during the menstrual period, including prolonged systolic and shortened diastolic phases, increases in pulse wave energy and area of representative pulse wave, and increased blood vessel resistance.

  2. SOLITONS: Nonlinear dynamics of optical pulses in fibres with a travelling refractive-index-change wave

    Science.gov (United States)

    Adamova, M. S.; Zolotovskii, Igor'O.; Sementsov, Dmitrii I.

    2009-03-01

    Dynamics of soliton-like wave packets in fibres with a travelling refractive-index-change wave is studied. It is shown that both a soliton-like propagation regime of a pulse and a self-compression regime in the region of normal group velocity dispersion are possible. It is also shown that in the case of a copropagating or counterpropagating pulse and optically inhomogeneous wave nonreciprocal effects appear.

  3. MOSFET-based high voltage double square-wave pulse generator with an inductive adder configuration

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Qiaogen, E-mail: hvzhang@mail.xjtu.edu.cn [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Long, Jinghua [College of Physics, Shenzhen University, Shenzhen 518060 (China); Lei, Yunfei; Liu, Jinyuan [Institute of Optoelectronics, Shenzhen University, Shenzhen 518060 (China)

    2015-09-01

    This paper presents a fast MOSFET-based solid-state pulse generator for high voltage double square-wave pulses. The generator consists mainly of an inductive adder system stacked of 20 solid-state modules. Each of the modules has 18 power MOSFETs in parallel, which are triggered by individual drive circuits; these drive circuits themselves are synchronously triggered by a signal from avalanche transistors. Our experiments demonstrate that the output pulses with amplitude of 8.1 kV and peak current of about 405 A are available at a load impedance of 20 Ω. The pulse has a double square-wave form with a rise and fall time of 40 ns and 26 ns, respectively and bottom flatness better than 12%. The interval time of the double square-wave pulses can be adjustable by varying the interval time of the trigger pulses.

  4. Estimation of Carotid Artery Pulse Wave Velocity by Doppler Ultrasonography

    Directory of Open Access Journals (Sweden)

    Mehdi Maerefat

    2009-06-01

    Full Text Available Background: Pulse wave velocity (PWV is widely used for estimating the stiffness of an artery. Various invasive and non-invasive methods have been developed to determine PWV over the years. In the present research, the non-invasive estimation of the PWV of large arteries was used as an index for arterial stiffness. Methods: A dynamic model based on the Navier-Stokes equations coupled to elasticity equations was introduced for the PWV in arteries with elastic walls. This system of equations was completed by clinical information obtained from the Doppler ultrasound images of the carotid artery of 40 healthy male volunteers. For this purpose, the Doppler ultrasound images were recorded and saved in a computer; and subsequently center-line blood velocity, arterial wall thickness, and arterial radius were measured by offline processing. Results: The results from the analytic solution of the completed equations showed that the mean value of PWV for the group of healthy volunteers was 2.35 m/s when the mean arterial radius was used as the neutral radius and 5.00 m/s when the end-diastole radius was used as the neutral radius. It is noteworthy that the latter value closely complies with that reported by other researchers. Conclusion: By applying this method, a non-invasive clinical and local evaluation of the common carotid artery stiffness via a Doppler ultrasound measurement will be possible.

  5. Weight Loss, Dietary Intake and Pulse Wave Velocity.

    Science.gov (United States)

    Petersen, Kristina; Blanch, Natalie; Keogh, Jennifer; Clifton, Peter

    2015-09-01

    We have recently conducted a meta-analysis to determine the effect of weight loss achieved by an energy-restricted diet with or without exercise, anti-obesity drugs or bariatric surgery on pulse wave velocity (PWV) measured at all arterial segments. Twenty studies, including 1,259 participants, showed that modest weight loss (8% of the initial body weight) caused a reduction in PWV measured at all arterial segments. However, due to the poor methodological design of the included studies, the results of this meta-analysis can only be regarded as hypothesis generating and highlight the need for further research in this area. In the future, well-designed randomised controlled trials are required to determine the effect of diet-induced weight loss on PWV and the mechanisms involved. In addition, there is observational evidence that dietary components such as fruit, vegetables, dairy foods, sodium, potassium and fatty acids may be associated with PWV, although evidence from well-designed intervention trials is lacking. In the future, the effect of concurrently improving dietary quality and achieving weight loss should be assessed in randomised controlled trials. PMID:26587462

  6. Estimation of aortic compliance using magnetic resonance pulse wave velocity measurement

    International Nuclear Information System (INIS)

    A method for compliance estimation employing magnetic resonance pulse wave velocity measurement is presented. Time-resolved flow waves are recorded at several positions along the vessel using a phase contrast sequence, and pulse wave velocity is calculated from the delay of the wave onsets. Using retrospective cardiac gating in combination with an optically decoupled electrocardiogram acquisition, a high temporal resolution of 3 ms can be achieved. A phantom set-up for the simulation of pulsatile flow in a compliant vessel is described. In the phantom, relative errors of pulse wave velocity estimation were found to be about 15%, whereas in a volunteer, larger errors were found that might be caused by vessel branches. Results of pulse wave velocity estimation agree with direct aortic distension measurements which rely on a peripheral estimate of aortic pressure and are therefore less accurate. Studies in 12 volunteers show values of pulse wave velocity consistent with the literature; in particular the well-known increase in pulse wave velocity with age was observed. Preliminary results show that the method can be applied to aortic aneurysms. (author)

  7. Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform.

    Directory of Open Access Journals (Sweden)

    Hau-Tieng Wu

    Full Text Available We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features.

  8. Underwater acoustic wave generation by filamentation of terawatt ultrashort laser pulses

    CERN Document Server

    Jukna, Vytautas; Milián, Carles; Brelet, Yohann; Carbonnel, Jérôme; André, Yves-Bernard; Guillermin, Régine; Sessarego, Jean-Pierre; Fattaccioli, Dominique; Mysyrowicz, André; Couairon, Arnaud; Houard, Aurélien

    2016-01-01

    Acoustic signals generated by filamentation of ultrashort TW laser pulses in water are characterized experimentally. Measurements reveal a strong influence of input pulse duration on the shape and intensity of the acoustic wave. Numerical simulations of the laser pulse nonlinear propagation and the subsequent water hydrodynamics and acoustic wave generation show that the strong acoustic emission is related to the mechanism of superfilamention in water. The elongated shape of the plasma volume where energy is deposited drives the far-field profile of the acoustic signal, which takes the form of a radially directed pressure wave with a single oscillation and a very broad spectrum.

  9. Association of Arterial Stiffness and Osteoporosis in Healthy Men Undergoing Screening Medical Examination

    OpenAIRE

    Kim, Nam Lee; Jang, Ha Min; Kim, Sul Ki; Ko, Ki Dong; Hwang, In Cheol; Suh, Heuy Sun

    2014-01-01

    Background Association of arterial stiffness and osteoporosis has been previously reported in women. However, this association is still controversial for men. Therefore, we investigated correlation of arterial stiffness and osteoporosis by measuring brachial-ankle (ba) pulse wave velocity (PWV) and bone mineral density (BMD). Methods We reviewed medical charts of 239 people (women: 128, men: 111) who visited the Health Promotion Center, retrospectively. ba-PWV was measured by automatic wave a...

  10. VLF wave stimulation by pulsed electron beams injected from the Space Shuttle

    Science.gov (United States)

    Reeves, G. D.; Banks, P. M.; Frazer-Smith, A. C.; Neubert, T.; Bush, R. I.

    1988-01-01

    Among the investigations conducted on the Space Shuttle flight STS-3 of March 1982 was an experiment in which a 1-keV, 100-mA electron gun was pulsed at 3.25 and 4.87 kHz. The resultant waves were measured with a broadband plasma wave receiver. At the time of flight the experimental setup was unique in that the electron beam was square wave modulated and that the Shuttle offered relatively long times for in situ measurements of the ionospheric plasma response to the VLF pulsing sequences. In addition to electromagnetic response at the pulsing frequencies the wave exhibited various spectral harmonics as well as the unexpected occurrence of 'satellite lines' around those harmonics. Both phenomena occurred with a variety of different characteristics for different pulsing sequences.

  11. Non-invasive measurement of aortic pressure in patients: Comparing pulse wave analysis and applanation tonometry

    OpenAIRE

    Naidu, M.U.R; C Prabhakar Reddy

    2012-01-01

    Objective: The aim of the present study was to validate and compare novel methods to determine aortic blood pressure non-invasively based on Oscillometric Pulse Wave Velocity (PWV) measurement using four limb-cuff pressure waveforms and two lead Electrocardiogram (ECG) with a validated tonometric pulse wave analysis system in patients. Materials and Methods: After receiving the consent, in 49 patients with hypertension, coronary artery disease, diabetes mellitus, PWV, and central blood p...

  12. A fast rise time high voltage pulse generator for bounded-wave EMP simulator

    International Nuclear Information System (INIS)

    A high voltage pulse generator with fast rise time is developed. The output wave of this generator is presented. The electromagnetic environment with 1.2 ns or 2.8 ns rise time and 50 ns pulse width can be produced when this generator is connected to bounded-wave EMP simulator which is used to investigate the EMP coupling effects of electrical equipment. (authors)

  13. Design and Implementation of High Frequency Ultrasound Pulsed-Wave Doppler Using FPGA

    OpenAIRE

    Hu, Chang-Hong; Zhou, Qifa; Shung, K. Kirk

    2008-01-01

    The development of a field-programmable gate array (FPGA)-based pulsed-wave Doppler processing approach in pure digital domain is reported in this paper. After the ultrasound signals are digitized, directional Doppler frequency shifts are obtained with a digital-down converter followed by a low-pass filter. A Doppler spectrum is then calculated using the complex fast Fourier transform core inside the FPGA. In this approach, a pulsed-wave Doppler implementation core with reconfigurable and rea...

  14. Selective excitation of the molecular rotational wave packet by two time-delayed laser pulses

    Institute of Scientific and Technical Information of China (English)

    Xu Shu-Wu; Huang Yun-Xia; Ji Xian-Ming

    2011-01-01

    In this paper,we investigate the control of the molecular wave packet of a linear molecule by two femtosecond laser pulses.It is shown that the odd and the even rotational wave packets created by a single laser pulse can be selectively excited by accurately controlling the time delay of another laser pulse.By inserting the peak of the second laser pulse at the position of maximum or minimum value around quarter or three quarter rotational period of the slope curve with odd (or even) rotational wave packet contribution that is created by the first laser pulse,the odd rotational wave packet can be enhanced (or suppressed) while the even rotational wave packet is suppressed (or enhanced).As a result,the molecular alignments around quarter and three quarter rotational periods can be obtained.Moreover,it is also shown that by inserting the second laser pulse around the quarter or three quarter rotational periods,the changes in the maximum degree of the molecular alignment for the odd and the even rotational wave packet contributions are consistent with their corresponding slope curves at these positions.

  15. Laser air-jet engine: the action of shock waves at low laser pulse repetition rates

    International Nuclear Information System (INIS)

    The impact and thermal action of laser sparks on the reflector of a laser engine in which the propulsion is produced by repetitively pulsed radiation is estimated. It is shown that for a low pulse repetition rate, the thermal contact of a plasma with the reflector and strong dynamic resonance loads are inevitable. These difficulties can be surmounted by using the method based on the merging of shock waves at a high pulse repetition rate. (laser applications)

  16. Relativistic solitary waves modulating long laser pulses in plasmas

    OpenAIRE

    Sánchez-Arriaga, G.; Siminos, E.; Lefebvre, E.

    2011-01-01

    This article discusses the existence of solitary electromagnetic waves trapped in a self-generated Langmuir wave and embedded in an infinitely long circularly polarized electromagnetic wave propagating through a plasma. From the mathematical point of view they are exact solutions of the 1-dimensional relativistic cold fluid plasma model with nonvanishing boundary conditions. Under the assumption of traveling wave solutions with velocity $V$ and vector potential frequency $\\omega$, the fluid m...

  17. EFFECTS OF CONTINUOUS-WAVE, PULSED, AND SINUSOIDAL-AMPLITUDE-MODULATED MICROWAVES ON BRAIN ENERGY METABOLISM

    Science.gov (United States)

    A comparison of the effects of continuous wave, sinusoidal-amplitude modulated, and pulsed square-wave-modulated 591-MHz microwave exposures on brain energy metabolism was made in male Sprague Dawley rats (175-225g). Brain NADH fluorescence, adensine triphosphate (ATP) concentrat...

  18. Characteristics of Spherical Shock Wave and Circular Pulse Jet Generated by Discharge of Propagating Shock Wave at Open End of Tube

    Institute of Scientific and Technical Information of China (English)

    Tsukasa Irie; Tsuyoshi Yasunobu; Hideo Kashimura; Toshiaki Setoguchi; Kazuyasu Matsuo

    2003-01-01

    When the shock wave propagating in the straight circular tube reaches at the open end, the impulsive wave is generated by the emission of a shock wave from an open end, and unsteady pulse jet is formed near the open end behind the impulsive wave under the specific condition. The pulse jet transits to spherical shock wave with the increase in the strength of shock wave. The strength is dependent on the Mach number of shock wave, which attenuates by propagation distance from the open end. In this study, the mechanism of generating the unsteady pulse jet, the characteristics of the pressure distribution in the flow field and the emission of shock wave from straight circular tube which has the infinite flange at open end are analyzed numerically by the TVD method. Strength of spherical shock wave, relation of shock wave Mach number, distance decay of spherical shock wave and directional characteristics are clarified.

  19. Aortic pulse wave velocity measurement in systemic sclerosis patients

    Directory of Open Access Journals (Sweden)

    M. Sebastiani

    2012-12-01

    Full Text Available Background. Systemic sclerosis (SSc is characterized by endothelial dysfunction and widespread microangiopathy. However, a macrovascular damage could be also associated. Aortic pulse wave velocity (aPWV is known to be a reliable indicator of arterial stiffness and a useful prognostic predictor of cardiovascular events. Moreover, aPWV may be easily measured by non-invasive, user-friendly tool. Aim of our study was to evaluate aPWV alterations in a series of SSc patients. Methods. The aPWV was evaluated in 35 consecutive female SSc patients and 26 sex- and age-matched healthy controls. aPWV alterations were correlated with cardiopulmonary involvement. Results. A significant increase of aPWV was observed in SSc patients compared to controls (9.4±3.2 m/s vs 7.3±1 m/s; P=0.002. In particular, 14/35 (40% SSc patients and only 1/26 (4% controls (P=0.0009 showed increased aPWV (>9 m/s cut-off value. Moreover, echocardiography evaluation showed an increased prevalence of right atrial and ventricular dilatation (atrial volume: 23.6±6.2 mL vs 20.3±4.3 mL, P=0.026; ventricular diameter 19.5±4.9 mm vs 15.9±1.6 mm; P=0.001 associated to higher values of pulmonary arterial systolic pressure (PAPs in SSc patients (31.5±10.4 mmHg vs 21.6±2.9 mmHg; P50 years old. Furthermore, altered aPWV was more frequently associated with limited cutaneous pattern, longer disease duration (≥5 years, and/or presence of anticentromere antibody (ACA. Conclusions. A significantly higher prevalence of abnormally increased aPWV was evidenced in SSc patients compared to healthy controls. The possibility of more pronounced and diffuse vascular damage in a particular SSc subset (ACA-positive subjects with limited cutaneous scleroderma and longer disease duration might be raised.

  20. Fifth-order intensity autocorrelations based on six-wave mixing of femtosecond laser pulses

    Science.gov (United States)

    Gaižauskas, Eugenijus; Steponkevičius, KÈ©stutis; Vaičaitis, Virgilijus

    2016-02-01

    It is shown both experimentally and by numerical simulations that fifth-order intensity autocorrelations of femtosecond laser pulses can be obtained from two-beam noncollinear six-wave mixing in air. A numerical analysis of competing direct and six-wave-assisted third-harmonic-generation pathways showed that these measurements are suitable for the background-free temporal characterization of laser pulses. Reshaping of the pulse and 10 fs subpulse formation during the primary stages of light filamentation were observed using the proposed method.

  1. a New Approach of Dynamic Blood Pressure Measurement Based on the Time Domain Analysis of the Pulse Wave

    Science.gov (United States)

    Zimei, Su; Wei, Xu; Hui, Yu; Fei, Du; Jicun, Wang; Kexin, Xu

    2009-08-01

    In this study the pulse wave characteristics were used as a new approach to measure the human blood pressure. Based the principle of pulse wave and theory of the elastic vascular, the authors analyzed the characteristic of the pulse waveforms and revealed the characteristics points which could be used to represent the blood pressure. In this investigation the relevant mathematical feature was used to identify the relationship between the blood pressure and pulse wave parameters in a more accurate way. It also provided an experimental basis to carry out continuing non-invasive blood pressure monitoring using the pulse wave method.

  2. Stationary periodic and solitary waves induced in an isotropic plasma by a strong short laser pulse

    International Nuclear Information System (INIS)

    A description of propagation of a relativistically intense short laser pulse into an isotropic plasma is presented. A kinetic equation for the spectral function of the electromagnetic (EM) waves is derived for an arbitrary amplitude pump wave, where the fully relativistic case is considered. The resulting kinetic equation of the spectral function is used along with the self of equations of the plasma to derive a general dispersion relation, and the importance of relativistic effects is pointed out. In the case of a superstrong short laser pulse novel Langmuir waves, with phase velocities larger than the speed of light, and waves of ion-sound type, which are damped only on ions, are found. In addition, for the case when the plasma density along with the mass of the electrons satisfies the 'frozen-in' condition, stationary nonlinear new type of ion-sound waves are investigated. The mechanism of the emission of these waves is also discussed. (author)

  3. Generation of high harmonics and attosecond pulses with ultrashort laser pulse filaments and conical waves

    Indian Academy of Sciences (India)

    A Couairon; A Lotti; D Faccio; P Di Trapani; D S Steingrube; E Schulz; T Binhammer; U Morgner; M Kovacev; M B Gaarde

    2014-08-01

    Results illustrating the nonlinear dynamics of ultrashort laser pulse filamentation in gases are presented, with particular emphasis on the filament properties useful for developing attosecond light sources. Two aspects of ultrashort pulse filaments are specifically discussed: (i) numerical simulation results on pulse self-compression by filamentation in a gas cell filled with noble gas. Measurements of high harmonics generated by the pulse extracted from the filament allows for the detection of intensity spikes and subcycle pulses generated within the filament. (ii) Simulation results on the spontaneous formation of conical wavepackets during filamentation in gases, which in turn can be used as efficient driving pulses for the generation of high harmonics and isolated attosecond pulses.

  4. A noninvasive method to estimate pulse wave velocity in arteries locally by means of ultrasound.

    Science.gov (United States)

    Brands, P J; Willigers, J M; Ledoux, L A; Reneman, R S; Hoeks, A P

    1998-11-01

    Noninvasive evaluation of vessel wall properties in humans is hampered by the absence of methods to assess directly local distensibility, compliance, and Young's modulus. Contemporary ultrasound methods are capable of assessing end-diastolic artery diameter, the local change in artery diameter as a function of time, and local wall thickness. However, to assess vessel wall properties of the carotid artery, for example, the pulse pressure in the brachial artery still must be used as a substitute for local pulse pressure. The assessment of local pulse wave velocity as described in the present article provides a direct estimate of local vessel wall properties (distensibility, compliance, and Young's modulus) and, in combination with the relative change in artery cross-sectional area, an estimate of the local pulse pressure. The local pulse wave velocity is obtained by processing radio frequency ultrasound signals acquired simultaneously along two M-lines spaced at a known distance along the artery. A full derivation and mathematical description of the method to assess local pulse wave velocity, using the temporal and longitudinal gradients of the change in diameter, are presented. A performance evaluation of the method was carried out by means of experiments in an elastic tube under pulsatile pressure conditions. It is concluded that, in a phantom set-up, the assessed local pulse wave velocity provides reliable estimates for local distensibility. PMID:10385955

  5. Multiple continuous-wave and pulsed modes of a figure-of-eight fibre laser

    Science.gov (United States)

    Pottiez, O.; Martinez-Rios, A.; Monzon-Hernandez, D.; Salceda-Delgado, G.; Hernandez-Garcia, J. C.; Ibarra-Escamilla, B.; Kuzin, E. A.

    2013-03-01

    We study experimentally a figure-of-eight fibre laser including a polarization-imbalanced nonlinear optical loop mirror and a Mach-Zehnder optical filter formed by two fibre tapers placed in series. Depending on the adjustments of two wave retarders included in the setup, different modes of operation of the laser are found. In continuous-wave mode, tunable single-wavelength operation as well as multiwavelength lasing are observed. For some adjustments, self-pulsing also takes place, although the pulses are very unstable. Finally, for some adjustments a mechanical stimulation (a kick) leads to the onset of passive mode locking. Measurements reveal that the mode-locked pulses actually are noise-like pulses. Both stable fundamental mode locking and second-harmonic mode locking with particular dynamics were obtained. In this work, we analyse how simple wave plate adjustments can lead to such a variety of operational modes of the fibre laser.

  6. INFLUENCE OF PULSED SHORT WAVE (DIAPULSE) TREATMENT ON THE BIOCHEMICAL PARAMETERS CORTISOL AND ALDOSTERONE

    OpenAIRE

    Dogaru Gabriela

    2015-01-01

    Pulsed short waves are part of high frequency therapy; unlike continuous short waves, where the phenomenon of tissular endothermia occurs, they have therapeutic effects that seem to depend rather on the interaction of electromagnetic waves with biological tissue, as they act only through specific electromagnetic energy. The recommended work technique for the use of the Diapulse device is that regardless of the exposed somatic region, there will be an initial exposure of one of the following r...

  7. Particle simulation and experimental study of the high-power narrow-pulse millimeter wave BWO

    International Nuclear Information System (INIS)

    The BWO (Backward-Wave Oscillator) slow-wave structure was optimized by the KARAT code, and the experiment was performed at the RADAD303 accelerator flat under the condition of the electron beam with the voltage of 177 kV, the current of 785A, and magnetic field of 1.7T. TE11 mode millimeter wave was generated, whose peak powe is 18 MW, frequency 39.8 GHz and pulse duration 3 ns. (authors)

  8. Attosecond xuv pulses for complete mapping of the time-dependent wave packets of D2+

    International Nuclear Information System (INIS)

    We have shown that the whole time-dependent vibrational wave packet of D2+ ions can be reconstructed from the kinetic energy release of the D+ ion pairs when it is probed with an attosecond xuv pulse. Such a full interrogation of the wave packet will pave the way for controlling the generation of tailor-designed wave packets for favorable chemical reaction paths, as well as for probing the time evolution of their interaction with the medium

  9. Eliminating the dipole phase in attosecond pulse characterization using Rydberg wave packets

    Science.gov (United States)

    Pabst, Stefan; Dahlström, Jan Marcus

    2016-07-01

    We propose a technique to fully characterize the temporal structure of extreme ultraviolet pulses by ionizing a bound coherent electronic wave packet. The influence of the dipole phase, which is the main obstacle for state-of-the-art pulse characterization schemes, can be eliminated by angle integration of the photoelectron spectrum. We show that in particular, atomic Rydberg wave packets are ideal and that wave packets involving multiple electronic states provide redundant information that can be used to cross-check the consistency of the phase reconstruction.

  10. Elimination of spiral waves and spatiotemporal chaos by the pulse with a specific spatiotemporal configuration

    Institute of Scientific and Technical Information of China (English)

    Yuan Guo-Yong; Yang Shi-Ping; Wang Guang-Rui; Chen Shi-Gang

    2008-01-01

    Spiral waves and spatiotemporal chaos are sometimes harmful and should be controlled.In this paper spiral waves and spatiotemporal chaos are successfully eliminated by the pulse with a very specific spatiotemporal configuration.The excited position D of spiral waves or spatiotemporal chaos is first recorded at an arbitrary time (to).When the system at the domain D enters a recovering state,the external pulse is injected into the domain.If the intensity and the working time of the pulse are appropriate,spiral waves and spatiotemporal chaos can finally be eliminated because counter-directional waves can be generated by the pulse.There are two advantages in the method.One is that the tip can be quickly eliminated together with the body of spiral wave,and the other is that the injected pulse may be weak and the duration can be very short so that the original system is nearly not affected,which is important for practical applications.

  11. Temporal broadening of pulsed waves propagating through turbulent media

    Institute of Scientific and Technical Information of China (English)

    XU; Zhengwen(许正文); WU; Jian(吴健); HUO; Wenping(霍文平); WU; Zhensen(吴振森)

    2003-01-01

    Pulse signals, propagating through a turbulent medium such as the ionosphere, can be distorted by dispersion and scattering from both the background medium and irregularities embedded in. Thus, the mean square pulse width is changed, and temporal broadening is introduced. We carry out a study on the temporal broadening with theoretical analyses and numerical simulations by using an analytical solution of two-frequency mutual coherence function obtained recently by iteration. As a case of study, pulse broadening is investigated in detail in trans-ionospheric propagation. Results show that most contributions are mainly from the dispersion of the background ionosphere and scattering effects of electron density irregularities in most cases.

  12. Attosecond electron pulses from interference of above-threshold de Broglie waves

    CERN Document Server

    Varro, Sandor

    2007-01-01

    It is shown that the the interference of above-threshold electron de Broglie waves, generated by an intense laser pulse at a metal surface yields attosecond electron pulses. This inerference is an analogon of the superposition of high harmonics generated from rare gas atoms, resulting in trains of attosecond light pulses.Owing to the inherent kinematic dispersion, the propagation of attosecond de Broglie waves in vacuum is very different from that of attosecond light pulses, which propagate without changing shape. Above the metal surface there are "collaps bands" and "revival layers" of the electron current even at macroscopic distances. In the range of parameters considered, the maximum value of the current densities of such ultrashort electron pulses has been estimated to be of order of couple of tenths of milliamps per square centimeters.

  13. Scattering of a partially coherent plane-wave pulse on a deterministic sphere

    International Nuclear Information System (INIS)

    The scattering of a partially coherent plane-wave pulse on a deterministic sphere is investigated. Analytical expression for the mutual coherence function of the scattered field is derived. It is shown that we can obtain the information of the sphere's position and its effective radius by measuring the time delay and pulse duration of the scattered field. The dependence of the pulse duration and temporal coherence length of the scattered field on the scattering angle and the parameters of the incident pulse is also illustrated numerically. -- Highlights: ► Scattering of a partially coherent plane-wave pulse on a deterministic sphere is investigated. ► We can obtain the sphere's information by measuring the parameters of the scattered field. ► Analytical expression for the mutual coherence function of the scattered field is derived. ► The dependence of the parameters of the scattered field on the scattering angle is illustrated.

  14. 强化降脂治疗对高血压合并高脂血症患者动脉脉搏波传导速度的影响%Effect of Artery Pulse Wave Velocity by Intensive Lipid-lowering Therapy in Patients with Hypertension Combined Hyperlipidemia

    Institute of Scientific and Technical Information of China (English)

    廖奕华; 邓云梅; 胡晶晶; 马艳丽; 樊琳

    2013-01-01

    cholesterol(HDL-C),low density lipoprotein(LDL-C),high sensitive C reactive protein(hs-CRP)and endothelin(ET)were detected before and after treatment.Result:Compared with normal group,two groups of patients baPWV, hs-CRP and ET levels were significantly elevated ,with significant difference(P<0.01),and it retreated significantly after 6 months treatment(P<0.01);compared with control group,which of intensive lipid-lowering group was decreased obviously,the difference was statistically significant between the groups(P<0.05).Conclusion:Patient with mild-to-moderate hypertension combined hyperlipidemia,intensive lipid-lowering therapy based on the control of blood pressure can futher improve the brachial-ankle artery pulse wave velocity,decreased hs-CRP and ET levels in patients,to improve the state of vascular function with a positive clinical significance.

  15. Studies of nanosecond pulse surface ionization wave discharges over solid and liquid dielectric surfaces

    International Nuclear Information System (INIS)

    Surface ionization wave discharges generated by high-voltage nanosecond pulses, propagating over a planar quartz surface and over liquid surfaces (distilled water and 1-butanol) have been studied in a rectangular cross section test cell. The discharge was initiated using a custom-made, alternating polarity, high-voltage nanosecond pulse plasma generator, operated at a pulse repetition rate of 100–500 Hz, with a pulse peak voltage and current of 10–15 kV and 7–20 A, respectively, a pulse FWHM of ∼100 ns, and a coupled pulse energy of 2–9 mJ/pulse. Wave speed was measured using a capacitive probe. ICCD camera images demonstrated that the ionization wave propagated predominantly over the quartz wall or over the liquid surface adjacent to the grounded waveguide placed along the bottom wall of the test cell. Under all experimental conditions tested, the surface plasma ‘sheet’ was diffuse and fairly uniform, both for positive and negative polarities. The parameters of ionization wave discharge propagating over distilled water and 1-butanol surfaces were close to those of the discharge over a quartz wall. No perturbation of the liquid surface by the discharge was detected. In most cases, the positive polarity surface ionization wave propagated at a higher speed and over a longer distance compared to the negative polarity wave. For all three sets of experiments (surface ionization wave discharge over quartz, water and 1-butanol), wave speed and travel distance decreased with pressure. Diffuse, highly reproducible surface ionization wave discharge was also observed over the liquid butanol–saturated butanol vapor interface, as well as over the distilled water–saturated water vapor interface, without buffer gas flow. No significant difference was detected between surface ionization discharges sustained using single-polarity (positive or negative), or alternating polarity high-voltage pulses. Plasma emission images yielded preliminary evidence of charge

  16. Single attosecond pulse generation via continuum wave packet interference

    Science.gov (United States)

    Zhou, Shengpeng; Yang, Yujun; Ding, Dajun

    2016-07-01

    A single attosecond pulse generation via continuum-continuum interference is investigated theoretically by exposing a single-electron atom in a femtosecond laser field with the intensity in over-the-barrier ionization regime. We show that the ground state of the atom is depleted in such intense laser field and the high-order harmonics (HHG) via continuum to continuum coherence are generated. In a few-cycle monochromatic laser field (5 fs/800 nm, 1.2×1016 W cm-2), a single attosecond pulse with duration of 49 as is obtained from the HHG. With a two-color laser field combined by 1200 nm (8 fs/7.5×1015 W cm-2) and 800 nm (5 fs/1.0×1016 W cm-2), a shorter single pulse with duration of 29 as can further be produced by changing the relative carrier envelope phase of two laser pulses as a result of controlling the electronic quantum path in the intense electric field. Our results also show that a short single attosecond pulse can be generated in a wide range of the relative carrier envelope phase of the two laser pulses.

  17. Arterial stiffness is inversely associated with a better running record in a full course marathon race

    OpenAIRE

    Jung, Su-Jeen; Park, Jae-Hyoung; Lee, Sewon

    2014-01-01

    [Purpose] Arterial stiffness is an independent predictor of cardiovascular risk and may contribute to reduced running capacity in humans. This study investigated the relationship between course record and arterial stiffness in marathoners who participated in the Seoul International Marathon in 2012. [Methods] A total of 30 amateur marathoners (Males n = 28, Females n = 2, mean age = 51.6 ± 8.3 years) were assessed before and after the marathon race. Brachial-ankle pulse wave velocity (ba-PWV)...

  18. Clinical Significance of Arterial Stiffness and Thickness Biomarkers in Type 2 Diabetes Mellitus: An Up-To-Date Meta-Analysis

    OpenAIRE

    Yapei, Yang; Xiaoyan, Ren; Sha, Zeng; Li, Pan; Xiao, Meng; Shuangfeng, Chen; Lexin, Wang; Lianqun, Cui

    2015-01-01

    Background Type 2 Diabetes mellitus (T2DM) is associated with increased risk of cardiovascular disease (CVD). Previous studies explored the association of T2DM with arterial stiffness and thickness biomarkers including the augmentation index (AIX), aortic pulse wave velocity (aPWV), brachial-ankle PWV (baPWV), carotid intima-media wall thickness (IMT) as well as blood pressure (BP), low density lipoprotein cholesterol (LDL-C); however the conclusions are either inconsistent or incomprehensive...

  19. The Role of Systemic Arterial Stiffness in Open-Angle Glaucoma with Diabetes Mellitus

    OpenAIRE

    Seong Hee Shim; Chan Yun Kim; Joon Mo Kim; Da Yeong Kim; Yang Jae Kim; Jeong Hun Bae; Ki Chul Sung

    2015-01-01

    Purpose. To investigate the role of systemic arterial stiffness in glaucoma patients with diabetes mellitus (DM). Design. Retrospective, cross-sectional study. Participants. DM subjects who underwent brachial-ankle pulse wave velocity (baPWV) were recruited. Methods. Glaucoma patients (n = 75) and age-matched control subjects (n = 92) were enrolled. Systemic examination including BaPWV and detailed eye examination were performed. The glaucoma group was divided into subgroups of normal tension...

  20. Association between non-alcoholic fatty liver disease and arterial stiffness in the non-obese, non-hypertensive, and non-diabetic young and middle-aged Chinese population

    OpenAIRE

    Yu, Xin-Yan; Zhao, Yi; Song, Xiao-xiao; Song, Zhen-ya

    2014-01-01

    Background and objective: Non-alcoholic fatty liver disease (NAFLD) is associated with arterial stiffness in the general population. Age, obesity, hypertension, and diabetics are risk factors for arterial stiffness. In this study, we aimed to investigate the association between NAFLD and arterial stiffness as measured by brachial-ankle pulse wave velocity (baPWV) in the non-obese, non-hypertensive, and non-diabetic young and middle-aged Chinese population. Methods: A cross-sectional study wit...

  1. Association of Interarm Systolic Blood Pressure Difference with Atherosclerosis and Left Ventricular Hypertrophy

    OpenAIRE

    Su, Ho-Ming; Lin, Tsung-Hsien; Hsu, Po-Chao; Chu, Chun-Yuan; Lee, Wen-Hsien; Chen, Szu-Chia; Lee, Chee-Siong; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung

    2012-01-01

    An interarm systolic blood pressure (SBP) difference of 10 mmHg or more have been associated with peripheral artery disease and adverse cardiovascular outcomes. We investigated whether an association exists between this difference and ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), and echocardiographic parameters. A total of 1120 patients were included in the study. The bilateral arm blood pressures were measured simultaneously by an ABI-form device. The values of ABI...

  2. Arterial Stiffening and Clinical Outcomes in Dialysis Patients

    OpenAIRE

    Kato, Akihiko

    2015-01-01

    Cardiovascular disease (CVD) is an important cause of morbidity and mortality in dialysis patients. Brachial-ankle pulse wave velocity (baPWV) is more efficient to handily assess arteriosclerosis than aortic PWV. The cardio-ankle vascular index (CAVI) is also a novel blood pressure-independent arterial stiffness parameter. In dialysis patients, both baPWV and CAVI are increased compared to general subjects. Several studies have demonstrated that increased baPWV is associated with carotid athe...

  3. Quantum-state-preserving optical pulse reshaping and multiplexing by four-wave mixing in a fiber

    DEFF Research Database (Denmark)

    McKinstrie, C. J.; Andersen, Lasse Mejling; Rottwitt, Karsten;

    2012-01-01

    Nondegenerate four-wave mixing driven by two pulsed pumps transfers the quantum state of an input signal pulse to an output idler pulse, which is a frequency-translated and reshaped version of the signal. By varying the pump shapes appropriately, one can connect signal and idler pulses with...

  4. Relativistic solitary waves modulating long laser pulses in plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Arriaga, G; Siminos, E; Lefebvre, E, E-mail: erik.lefebvre@cea.fr [CEA, DAM, DIF, 91297 Arpajon (France)

    2011-04-15

    This paper discusses the existence of solitary electromagnetic waves trapped in a self-generated Langmuir wave and embedded in an infinitely long circularly polarized electromagnetic wave propagating through a plasma. From a mathematical point of view they are exact solutions of the one-dimensional relativistic cold fluid plasma model with nonvanishing boundary conditions. Under the assumption of travelling wave solutions with velocity V and vector potential frequency {omega}, the fluid model is reduced to a Hamiltonian system. The solitary waves are homoclinic (grey solitons) or heteroclinic (dark solitons) orbits to fixed points. Using a dynamical systems description of the Hamiltonian system and a spectral method, we identify a large variety of solitary waves, including asymmetric ones, discuss their disappearance for certain parameter values and classify them according to (i) grey or dark character, (ii) the number of humps of the vector potential envelope and (iii) their symmetries. The solutions come in continuous families in the parametric V-{omega} plane and extend up to velocities that approach the speed of light. The stability of certain types of grey solitary waves is investigated with the aid of particle-in-cell simulations that demonstrate their propagation for a few tens of the inverse of the plasma frequency.

  5. Estimation of global aortic pulse wave velocity by flow-sensitive 4D MRI.

    Science.gov (United States)

    Markl, Michael; Wallis, Wolf; Brendecke, Stefanie; Simon, Jan; Frydrychowicz, Alex; Harloff, Andreas

    2010-06-01

    The aim of this study was to determine the value of flow-sensitive four-dimensional MRI for the assessment of pulse wave velocity as a measure of vessel compliance in the thoracic aorta. Findings in 12 young healthy volunteers were compared with those in 25 stroke patients with aortic atherosclerosis and an age-matched normal control group (n = 9). Results from pulse wave velocity calculations incorporated velocity data from the entire aorta and were compared to those of standard methods based on flow waveforms at only two specific anatomic landmarks. Global aortic pulse wave velocity was higher in patients with atherosclerosis (7.03 +/- 0.24 m/sec) compared to age-matched controls (6.40 +/- 0.32 m/sec). Both were significantly (P sec). Global aortic pulse wave velocity in young volunteers was in good agreement with previously reported MRI studies and catheter measurements. Estimation of measurement inaccuracies and error propagation analysis demonstrated only minor uncertainties in measured flow waveforms and moderate relative errors below 16% for aortic compliance in all 46 subjects. These results demonstrate the feasibility of pulse wave velocity calculation based on four-dimensional MRI data by exploiting its full volumetric coverage, which may also be an advantage over standard two-dimensional techniques in the often-distorted route of the aorta in patients with atherosclerosis. PMID:20512861

  6. Validity and reproducibility of arterial pulse wave velocity measurement using new device with oscillometric technique: A pilot study

    OpenAIRE

    Patnaik Amar; Yashmaina Sridhar; Reddy Budda; Naidu Madireddy; Rani Pingali

    2005-01-01

    Abstract Background Availability of a range of techniques and devices allow measurement of many variables related to the stiffness of large or medium sized arteries. There is good evidence that, pulse wave velocity is a relatively simple measurement and is a good indicator of changes in arterial properties. The pulse wave velocity calculated from pulse wave recording by other methods like doppler or tonometry is tedious, time-consuming and above all their reproducibility depends on the operat...

  7. ARE PULSING SOLITARY WAVES RUNNING INSIDE THE SUN?

    International Nuclear Information System (INIS)

    A precise sequence of frequencies—detected four independent ways—is interpreted as a system of solitary waves below the Sun's convective envelope. Six future observational or theoretical tests of this idea are suggested. Wave properties (rotation rates, radial energy distribution, nuclear excitation strength) follow from conventional dynamics of global oscillation modes after assuming a localized nuclear term strong enough to perturb and hold mode longitudes into alignments that form 'families'. To facilitate future tests, more details are derived for a system of two dozen solitary waves 2 ≤ l ≤ 25. Wave excitation by 3He and 14C burning is complex. It spikes by factors M1 ≤ 103 when many waves overlap in longitude but its long-time average is M2 ≤ 10. Including mixing can raise overall excitation to ∼50 times that in a standard solar model. These spikes cause tiny phase shifts that tend to pull wave rotation rates toward their ideal values ∝[l(l + 1)]–1. A system like this would generate some extra nuclear energy in two spots at low latitude on opposite sides of the Sun. Each covers about 20° of longitude. Above a certain wave amplitude, the system starts giving distinctly more nuclear excitation to some waves (e.g., l = 9, 14, and 20) than to neighboring l values. The prominence of l = 20 has already been reported. This transition begins at temperature amplitudes ΔT/T = 0.03 in the solar core for a typical family of modes, which corresponds to δT/T ∼ 0.001 for one of its many component oscillation modes.

  8. Generation of shock waves in dense plasmas by high-intensity laser pulses

    OpenAIRE

    Pasley John; Bush I. A.; Robinson Alexander P. L.; Rajeev P. P.; Mondal S; Lad A. D.; Ahmed S; Narayanan V; Kumar G. Ravindra; Kingham Robert J.

    2015-01-01

    When intense short-pulse laser beams (I > 1022 W/m2, τ < 20 ps) interact with high density plasmas, strong shock waves are launched. These shock waves may be generated by a range of processes, and the relative significance of the various mechanisms driving the formation of these shock waves is not well understood. It is challenging to obtain experimental data on shock waves near the focus of such intense laser–plasma interactions. The hydrodynamics of such interactions is, however, of great i...

  9. Associations between plasma fibulin-1, pulse wave velocity and diabetes in patients with coronary heart disease

    DEFF Research Database (Denmark)

    Hansen, Maria Lyck; Rasmussen, Lars Melholt

    2015-01-01

    BACKGROUND: Diabetes is related to increased risk of cardiovascular disease, and arterial stiffness and its consequences may be the factor connecting the two. Arterial stiffness is often measured by carotid-femoral pulse wave velocity (cf-PWV), but no plasma biomarker reflecting arterial stiffness...... is available. Fibulin-1 is an extracellular matrix protein, up-regulated in arterial tissue and in plasma in patients with type 2 diabetes. We aimed to evaluate the association between plasma fibulin-1 and arterial stiffness measured by cf PWV in a group of patients with diabetes, and one without......, all undergoing coronary artery bypass grafting. METHODS: Pulse wave velocity (PWV) and pulse wave analysis including augmentation index (Aix75) was measured in 273 patients, who subsequently underwent a coronary by-pass operation. Plasma samples were drawn and information was gathered on diabetes...

  10. Effects of azelnidipine and amlodipine on artery stiffness and dynamic pulse pressure in patients with essential hypertension%阿折地平与氨氯地平对高血压病患者动脉僵硬度与动态脉压的影响

    Institute of Scientific and Technical Information of China (English)

    黄荣杰; 郑云香; 何美霖

    2012-01-01

    Objective To investigate the impacts of azelnidipine and mlodipine on artery stiffness and dynamic pulse pressure in patients with essential hypertension. Methods Seventy-six hypertensive patients were enrolled into the azelnidipine group and the amlodipine group in this randomized double-blind study. Each patient was given azelnidipine (8 mg) or amlodipine (5 mg) orally everyday for 12 weeks after placebo treatment. The biochemical items, the automatic blood pressure monitor (ABPM) and the brachial ankle pulse wave velocity (baPWV) were determined before and after drug treatment, respectively. Results (1) The seat pressure, ABPM paremnents, baPWV and APP decreased in two groups after 12- week treatment, respectively. (2) No significant differences for the ABPM paremnents, baPWV and APP were shown in two groups. Conclusion Azelnidipine and amlodipine can both markedly decrease baPWV and APP in patients with essential hypertension with no significant difference.%目的:研究阿折地平与氨氯地平对轻中度高血压病患者动脉僵硬度及动态脉压差(APP)的影响.方法:随机双盲双模拟平行对照将76例高血压病患者分为阿折地平组和氨氯地平组,安慰剂期后进入12周试验期,给予阿折地平8 mg或氨氯地平5 mg,每天1次,口服,安慰剂期及试验期结束前行常规生化、动态血压监测、踝-臂脉搏波传导速度(baPWV)测定.结果:(1)与治疗前相比,两组患者坐位及动态血压参数、baPWV及APP均明显降低;(2)12周后两组患者相比,动态血压参数、APP及baPWV均无明显差异.结论:阿折地平与氨氯地平均能有效降低轻中度高血压病患者动脉僵硬度及APP,但两者疗效无明显差异.

  11. Pulse wave imaging in normal, hypertensive and aneurysmal human aortas in vivo: a feasibility study

    Science.gov (United States)

    Li, Ronny X.; Luo, Jianwen; Balaram, Sandhya K.; Chaudhry, Farooq A.; Shahmirzadi, Danial; Konofagou, Elisa E.

    2013-07-01

    Arterial stiffness is a well-established biomarker for cardiovascular risk, especially in the case of hypertension. The progressive stages of an abdominal aortic aneurysm (AAA) have also been associated with varying arterial stiffness. Pulse wave imaging (PWI) is a noninvasive, ultrasound imaging-based technique that uses the pulse wave-induced arterial wall motion to map the propagation of the pulse wave and measure the regional pulse wave velocity (PWV) as an index of arterial stiffness. In this study, the clinical feasibility of PWI was evaluated in normal, hypertensive, and aneurysmal human aortas. Radiofrequency-based speckle tracking was used to estimate the pulse wave-induced displacements in the abdominal aortic walls of normal (N = 15, mean age 32.5 ± 10.2 years), hypertensive (N = 13, mean age 60.8 ± 15.8 years), and aneurysmal (N = 5, mean age 71.6 ± 11.8 years) human subjects. Linear regression of the spatio-temporal variation of the displacement waveform in the anterior aortic wall over a single cardiac cycle yielded the slope as the PWV and the coefficient of determination r2 as an approximate measure of the pulse wave propagation uniformity. The aortic PWV measurements in all normal, hypertensive, and AAA subjects were 6.03 ± 1.68, 6.69 ± 2.80, and 10.54 ± 6.52 m s-1, respectively. There was no significant difference (p = 0.15) between the PWVs of the normal and hypertensive subjects while the PWVs of the AAA subjects were significantly higher (p pathologies that regionally alter the arterial wall mechanics.

  12. Prognostic value of aortic pulse wave velocity as index of arterial stiffness in the general population

    OpenAIRE

    Willum-Hansen, Tine; Staessen, Jan A.; Torp-Pedersen, Christian; Rasmussen, Susanne; Thijs, Lutgarde; Ibsen, Hans; Jeppesen, Jørgen

    2006-01-01

    BACKGROUND: Few population studies addressed the prognostic significance of aortic pulse wave velocity (APWV) above and beyond other cardiovascular risk factors. METHODS AND RESULTS: We studied a sex- and age-stratified random sample of 1678 Danes aged 40 to 70 years. We used Cox regression to investigate the prognostic value of APWV, office pulse pressure (PP), and 24-hour ambulatory PP while adjusting for mean arterial pressure (MAP) and other covariates. Over a median follow-up of 9.4 year...

  13. Micro-joule sub-10-fs VUV pulse generation by MW pump pulse using highly efficient chirped-four-wave mixing in hollow-core photonic crystal fibers

    OpenAIRE

    Im, Song-Jin

    2013-01-01

    We theoretically study chirped four-wave mixing for VUV pulse generation in hollow-core photonic crystal fibers. We predict the generation of sub-10-fs VUV pulses with energy of up to hundreds of microjoule by broad-band chirped idler pulses at 830 nm and MW pump pulses with narrow-band at 277 nm. MW pump could be desirable to reduce the complexity of the laser system or use a high repetition rate-laser system. The energy conversion efficiency from pump pulse to VUV pulse reaches to 30%. This...

  14. Shock wave generation in laser ablation studied using pulsed digital holographic interferometry

    International Nuclear Information System (INIS)

    Pulsed digital holographic interferometry has been used to study the shock wave induced by a Q-switched Nd-YAG laser (λ = 1064 nm and pulse duration 12 ns) on a polycrystalline boron nitride (PCBN) ceramic target under atmospheric air pressure. A special setup based on using two synchronized wavelengths from the same laser for processing and measurement simultaneously has been introduced. Collimated laser light (λ = 532 nm) passed through the volume along the target and digital holograms were recorded for different time delays after processing starts. Numerical data of the integrated refractive index field were calculated and presented as phase maps showing the propagation of the shock wave generated by the process. The location of the induced shock wave front was observed for different focusing and time delays. The amount of released energy, i.e. the part of the incident energy of the laser pulse that is eventually converted to a shock wave has been estimated using the point explosion model. The released energy is normalized by the incident laser pulse energy and the energy conversion efficiency between the laser pulse and PCBN target has been calculated at different power densities. The results show that the energy conversion efficiency seems to be constant around 80% at high power densities.

  15. Magnetostatic-Wave-Based Magneto-Optic Pulse Compression by Control of Phase Mismatching

    Institute of Scientific and Technical Information of China (English)

    WU Bao-Jian; GAO Xiang

    2008-01-01

    Microwave magnetostatic waves (MSWs) as moving gratings in magneto-optic (MO) film can lead to the Bragg diffraction of guided optical waves (GOWs). The MO coupling characteristics are responsible for the amplitude and phase frequency spectra of diffracted pulses and even result in the compression of chirped optical pulses in time domain. We theoretically investigate the noncollinear diffraction of linearly chirped Gaussian optical pulses by continuous magnetostatic forward volume waves in detail. For a given chirped optical pulse, with the increase of phase-mismatching slopes, the compression efficiency (CE) is gradually improved up to the maximum followed by the transition of diffracted pulses from single peak to multi peaks. The larger the chirp parameter is,the smaller the required phase-mismatching slope to achieve the maximal CE is. However, the rise of the chirp parameter or phase-mismatching slope reduces the relative peak intensity of the diffracted pulse. Lastly, it is pointed out that the phase-mismatching slope can be greatly increased by using the high-order modes of MSWs and GOWs.

  16. VLF wave emissions by pulsed and dc electron beams in space. I - Spacelab 2 observations

    Science.gov (United States)

    Reeves, G. D.; Banks, P. M.; Neubert, T.; Bush, R. I.; Williamson, P. R.

    1988-01-01

    The properties of radio waves generated by electron beams in space were investigated using data from the wideband wave receiver on the Spacelab 2. The VLF observations were found to confirm the results of the STS 3/OSS-1 mission. It was found that a 1-keV electron beam injected from the orbiter produced copious broadband electromagnetic emissions. When the electron beam was square-wave modulated, narrow-band emissions at the pulsing frequency and harmonics of that frequency were produced along with the broadband emissions. The observations indicated that dc 50-mA electron beams and pulsed 50-percent duty-cycle 100-mA beams produce broadband radiation which is comparable in intensity and spectral shape at all points for which the wave field was sampled.

  17. Group Velocity Reduction of Light Pulses in Photorefractive Two-Wave Mixing

    Institute of Scientific and Technical Information of China (English)

    张国权; 董嵘; 许京军

    2003-01-01

    We show theoretically that the group velocity of light pulses can be reduced significantly by use of the steep dispersion properties of the phase coupling effect in the photorefractive two-wave mixing process. The group velocity of light pulses of the order of 0.1 m/s can be achieved in typical photorefractive BSOcrystals with an appropriate externally applied electric field and moving gratings of appropriate speeds. It is also shown that the slowly propagating light pulses can be set to be amplified after passing through the photorefractive material.

  18. Influence of tilt load on pulse wave velocity in the lower limbs

    Czech Academy of Sciences Publication Activity Database

    Plešinger, Filip; Matějková, M.; Halámek, Josef; Jurák, Pavel; Viščor, Ivo; Vondra, Vlastimil

    Trento : IEEE, 2014, s. 77-78. ISBN 978-1-4799-3968-8. [ESGCO 2014. Conference European Study Group on Cardiovascular Oscillations /8./. Trento (IT), 25.05.2014-28.05.2014] R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : pulse wave * wave velocity Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  19. A Distinguishing Arterial Pulse Waves Approach by Using Image Processing and Feature Extraction Technique.

    Science.gov (United States)

    Chen, Hsing-Chung; Kuo, Shyi-Shiun; Sun, Shen-Ching; Chang, Chia-Hui

    2016-10-01

    Traditional Chinese Medicine (TCM) is based on five main types of diagnoses methods consisting of inspection, auscultation, olfaction, inquiry, and palpation. The most important one is palpation also called pulse diagnosis which is to measure wrist artery pulse by doctor's fingers for detecting patient's health state. In this paper, it is carried out by using a specialized pulse measuring instrument to classify one's pulse type. The measured pulse waves (MPWs) were segmented into the arterial pulse wave curve (APWC) by image proposing method. The slopes and periods among four specific points on the APWC were taken to be the pulse features. Three algorithms are proposed in this paper, which could extract these features from the APWCs and compared their differences between each of them to the average feature matrix, individually. These results show that the method proposed in this study is superior and more accurate than the previous studies. The proposed method could significantly save doctors a large amount of time, increase accuracy and decrease data volume. PMID:27562483

  20. Coherent control of population and pulse propagation beyond the rotating wave approximation

    International Nuclear Information System (INIS)

    The dynamics of populations of the vibrational states in a NO molecule (one-photon absorption) and of the electronic states in a 4,4'-bis(dimethylamino) stilbene molecule (two-photon absorption) is studied versus the frequency, intensity and shape of the laser pulse. We show that specially designed infrared laser pulses can build selective populations of certain vibrational states. A detuning of light frequency from the vibrational resonance qualitatively changes the dynamics of populations. It is found out that the populations of the nonresonant levels follow the pulse shape adiabatically if the detuning significantly exceeds the inverse characteristic time of the change of the pulse. Depopulation of the nonresonant vibrational states leads to a high population of the resonant state at the end of the pulse. Complete breakdown of the standard rotating wave approximation for a two-photon absorption process is observed even for a rather small intensity of the laser pulse. An analytical solution for the interaction of a pulse with a three-level system beyond the rotating wave approximation is obtained, and it is in close agreement with the strict numerical solution of the amplitude equations. Special attention is paid to the population dynamics of randomly oriented molecules. The orientational disorder as well as the vibrations limit the coherent population transfer. Calculations show the strong role of the anisotropy of photoexcitation in the coherent control of populations which can affect the anisotropy of photobleaching

  1. A comparative study of chop-wave and super pulse CO-2 laser surface modification of polyurethane

    International Nuclear Information System (INIS)

    The present study was undertaken to evaluate and compare the effects of chop wave and super pulse wave of CO2 laser on polyurethane. The results showed that at the threshold fluences of 200 and 400 mJcm-2, for chop wave and super pulse wave, the final temperatures would be about 322 and 343 K justified by their effective absorption coefficients of ∼ 1 . 2 x 1 03cm-1and 1.3 x 103cm-1, respectively. These values are well below the minimum melting temperature (≅393 K) of polymer. The ATR-FTIR spectral analysis showed four new peaks at 1436, 1370, 1259 and 958 cm-Iafter laser irradiation indicative of increased hydrogen bonding. The best surface free energy of 50 mNm-1was obtained after 8 pulses of chop wave which corresponds to a contact angle of 75 .Topological studies using SEM evaluation illustrated that a smooth wall crater can be produced by super pulse wave and chop wave at higher laser pulse numbers and relatively low input power.Finally, in our experiments the highest value of surface free energy was achieved by chop wave mode at 0.1 W after 8 pulses. Although, super pulse wave produced a narrower zone of thermal degradation, surface free energy of polymer, however was found to be weaker than chop wave mode

  2. Transporting Rydberg Electron Wave Packets with Chirped Trains of Pulses

    International Nuclear Information System (INIS)

    A protocol for steering Rydberg electrons towards targeted final states is realized with the aid of a chirped train of half-cycle pulses (HCPs). Its novel capabilities are demonstrated experimentally by transporting potassium atoms excited to the lowest-lying quasi-one-dimensional states in the ni=350 Stark manifold to a narrow range of much higher-n states. We demonstrate that this coherent state transfer is, to a high degree, reversible. The protocol allows for remarkable selectivity and is highly efficient, with typically over 80% of the parent atoms surviving the HCP sequence

  3. Full-wave reflection of lightning long-wave radio pulses from the ionospheric D region: Numerical model

    Science.gov (United States)

    Jacobson, Abram R.; Shao, Xuan-Min; Holzworth, Robert

    2009-03-01

    A model is developed for calculating ionospheric reflection of electromagnetic pulses emitted by lightning, with most energy in the long-wave spectral region (f ~ 3-100 kHz). The building block of the calculation is a differential equation full-wave solution of Maxwell's equations for the complex reflection of individual plane waves incident from below, by the anisotropic, dissipative, diffuse dielectric profile of the lower ionosphere. This full-wave solution is then put into a summation over plane waves in an angular direct Fourier transform to obtain the reflection properties of curved wavefronts. This step models also the diffraction effects of long-wave ionospheric reflections observed at short or medium range (~200-500 km). The calculation can be done with any arbitrary but smooth dielectric profile versus altitude. For an initial test, this article uses the classic D region exponential profiles of electron density and collision rate given by Volland. With even these simple profiles, our model of full-wave reflection of curved wavefronts captures some of the basic attributes of observed reflected waveforms recorded with the Los Alamos Sferic Array. A follow-on article will present a detailed comparison with data in order to retrieve ionospheric parameters.

  4. Pulse-wave timing between the cervical carotid and intracranial arteries by means of wavelet transform

    NARCIS (Netherlands)

    Journee, HL; de Jonge, AB; Hamoen, DJ; Smit, A; van Bruggen, AC; Mooij, JJA; Boom, H; Robinson, C; Rutten, W; Neuman, M; Wijkstra, H

    1997-01-01

    Wavelet Transform (WT) is applied in a method for timing the blood pulse wave between the internal carotid artery: and one of the intracranial arteries. The required accuracy is a few milliseconds. In contrast to the Fourier Transform (FT), WT is an appropriate technique for the detection of non-sta

  5. Imaging pulse wave velocity in mouse retina using swept-source OCT (Conference Presentation)

    Science.gov (United States)

    Song, Shaozhen; Wei, Wei; Wang, Ruikang K.

    2016-03-01

    Blood vessel dynamics has been a significant subject in cardiology and internal medicine, and pulse wave velocity (PWV) on artery vessels is a classic evaluation of arterial distensibility, and has never been ascertained as a cardiovascular risk marker. The aim of this study is to develop a high speed imaging technique to capture the pulsatile motion on mouse retina arteries with the ability to quantify PWV on any arterial vessels. We demonstrate a new non-invasive method to assess the vessel dynamics on mouse retina. A Swept-source optical coherence tomography (SS-OCT) system is used for imaging micro-scale blood vessel motion. The phase-stabilized SS-OCT provides a typical displacement sensitivity of 20 nm. The frame rate of imaging is ~16 kHz, at A-line rate of ~1.62 MHz, which allows the detection of transient pulse waves with adequate temporal resolution. Imaging volumes with repeated B-scans are obtained on mouse retina capillary bed, and the mouse oxymeter signal is recorded simultaneously. The pulse wave on artery and vein are resolved, and with the synchronized heart beat signal, the temporal delay on different vessel locations is determined. The vessel specific measurement of PWV is achieved for the first time with SS-OCT, for pulse waves propagating more than 100 cm/s. Using the novel methodology of retinal PWV assessment, it is hoped that the clinical OCT scans can provide extended diagnostic information of cardiology functionalities.

  6. Theory of nondegenerate four-wave mixing between pulses in a semiconductor waveguide

    DEFF Research Database (Denmark)

    Mørk, Jesper; Mecozzi, A.

    1997-01-01

    We develop a perturbation theory for calculating the effects of saturation on nondegenerate four-wave mixing between short optical pulses in a semiconductor optical amplifier. Saturation due to ultrafast intraband dynamics like carrier heating and spectral hole burning is found to be important for...

  7. Clinical characteristic of pulse wave velocity and arterial compliance in elderly patients with diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    张红

    2013-01-01

    Objective To explore the clinical characteristics of pulse wave velocity,arterial compliance and cardiovascular risk factors in elderly patients with type 2 diabetes mellitus.Methods A total of 363 patients were selected and divided into 4 groups:diabetic group,diabetic

  8. Comparison of two instruments measuring carotid-femoral pulse wave velocity: Vicorder versus SphygmoCor

    NARCIS (Netherlands)

    E.M. van Leeuwen-Segarceanu; W.F. Tromp; W.J.W. Bos; O.J. Vogels; J.W. Groothoff; J.H. van der Lee

    2010-01-01

    Background The carotid-femoral pulse wave velocity (PWVcf) is used as an indicator of arterial stiffness. It is often measured using applanation tonometry, for instance with the SphygmoCor. In young children, this method is difficult to perform. Therefore, techniques are needed that are less depende

  9. Changes of Pulse Wave Velocity in the Lower Limbs in Hypertensive Patients

    Czech Academy of Sciences Publication Activity Database

    Matějková, M.; Vondra, Vlastimil; Soukup, L.; Plešinger, Filip; Viščor, Ivo; Halámek, Josef; Jurák, Pavel

    Cambridge: Computing in Cardiology, 2015, s. 257-260. ISBN 978-1-5090-0685-4. ISSN 2325-8861. [Computing in Cardiology 2015. Nice (FR), 06.09.2015-11.09.2015] Institutional support: RVO:68081731 Keywords : pulse wave velocity * bioimpedance * plethysmography * hypertension * tilt table Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  10. Relations between diabetes, blood pressure and aortic pulse wave velocity in haemodialysis patients

    DEFF Research Database (Denmark)

    Peters, Christian Daugaard; Kjærgaard, Krista Dybtved; Dzeko, Mirela;

    Diabetes (DM) is common in haemodialysis (HD) patients and affects both blood pressure (BP) and arterial stiffness. Carotid femoral pulse wave velocity (PWV) reflects the stiffness of the aorta and is regarded as a strong risk factor for cardiovascular (CV) mortality in HD patients. However, PWV is...

  11. Effect of square wave pulse on the deposition structure of gold nanoparticles

    OpenAIRE

    ZIPINGI AI; SHENHAO CHEN; SHIYONG ZHAO; SHENGBIN LEI

    1999-01-01

    Electrophoretic deposition (EPD) of colloidal particles is a newly developed method for the fabrication of colloidal particle superlattices. By modifying the EPD procedure with square wave pulse, multilayer formation of gold particles is reduced and a more orderly packed monolayer can be prepared.

  12. Traveling-wave pulse on a superconductive active transmission line using resonant tunneling diodes

    International Nuclear Information System (INIS)

    Analytic study and computer experiment investigations on a superconductive active transmission line using resonant tunneling diodes (RTDs) are discussed. It is shown, based on nonlinear wave propagation effects, that the line supports pulse propagation appearing as pairs of kink–antikink profiles. This behavior is due to compensation between the effects of amplification and dissipation along the network. (paper)

  13. Traveling-wave pulse on a superconductive active transmission line using resonant tunneling diodes

    Science.gov (United States)

    Klofaï, Yerima; Essimbi, B. Z.; Jäger, D.

    2013-10-01

    Analytic study and computer experiment investigations on a superconductive active transmission line using resonant tunneling diodes (RTDs) are discussed. It is shown, based on nonlinear wave propagation effects, that the line supports pulse propagation appearing as pairs of kink-antikink profiles. This behavior is due to compensation between the effects of amplification and dissipation along the network.

  14. The use of pulsed-wave Doppler in prenatal diagnosis. An update

    OpenAIRE

    Degani, S.

    2007-01-01

    Pulsed wave Doppler ultrasound of fetal vessels confirms the similarity of human fetal circulation to the experimental animal physiology, The result of a multitude of research articles in this field is the clinical use of various components of fetal circulation in perinatal medicine. Umbilical, uterine and fetal cerebral arteries as well as the fetal venous circulation show the potential of Doppler ultrasonography.

  15. Dissipation of Alfven wave pulses propagating along dipole magnetic tubes with reflections at the ionosphere

    NARCIS (Netherlands)

    Erkaev, NV; Shaidurov, VA; Semenov, VS; Biernat, HK; Heidorn, D; Lakhina, GS

    2006-01-01

    A ratio of the maximal and minimal cross sections of the magnetic tube (contraction ratio) is a crucial parameter which affects very strongly on reflections of MHD wave pulses propagating along a narrowing magnetic flux tube. In cases of large contraction ratios of magnetospheric magnetic tubes, the

  16. Diode-pumped intracavity optical parametric oscillator in pulsed and continuous-wave operation

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Skettrup, Torben; Petersen, O.B.; Larsen, M.B.

    2002-01-01

    An intracavity optical parametric oscillator is investigated in pulsed and continuous-wave operation. The intracavity optical parametric oscillator is based on Yb:YAG as the laser material and a periodically poled lithium niobate crystal as the nonlinear material. Tuneable idler output powers above...

  17. Scattering of a pulsed wave by a sphere with an eccentric spherical inclusion.

    Science.gov (United States)

    Vervelidou, Fotini; Chrissoulidis, Dimitrios

    2012-04-01

    A dielectric sphere with an eccentric spherical dielectric inclusion and an incident amplitude-modulated plane electromagnetic wave constitute an exterior radiation problem, which is solved in this paper. A solution is obtained by combined use of the Fourier transform and the indirect-mode-matching method. The analysis yields a set of linear equations for the wave amplitudes of the frequency-domain expansion of the electric-field intensity within and outside the externally spherical inhomogeneous body; that set is solved by truncation and matrix inversion. The shape of the backscattered pulse in the time domain is determined by application of the inverse fast Fourier transform. Numerical results are shown for a pulse backscattered by an acrylic sphere that contains an eccentric spherical cavity. The effects of cavity position and size on pulse spreading and delay are discussed. PMID:22472840

  18. Non-contact measurement of pulse wave velocity using RGB cameras

    Science.gov (United States)

    Nakano, Kazuya; Aoki, Yuta; Satoh, Ryota; Hoshi, Akira; Suzuki, Hiroyuki; Nishidate, Izumi

    2016-03-01

    Non-contact measurement of pulse wave velocity (PWV) using red, green, and blue (RGB) digital color images is proposed. Generally, PWV is used as the index of arteriosclerosis. In our method, changes in blood volume are calculated based on changes in the color information, and is estimated by combining multiple regression analysis (MRA) with a Monte Carlo simulation (MCS) model of the transit of light in human skin. After two pulse waves of human skins were measured using RGB cameras, and the PWV was calculated from the difference of the pulse transit time and the distance between two measurement points. The measured forehead-finger PWV (ffPWV) was on the order of m/s and became faster as the values of vital signs raised. These results demonstrated the feasibility of this method.

  19. Allowable propagation of short pulse laser beam in a plasma channel and electromagnetic solitary waves

    International Nuclear Information System (INIS)

    Nonparaxial and nonlinear propagation of a short intense laser beam in a parabolic plasma channel is analyzed by means of the variational method and nonlinear dynamics. The beam propagation properties are classified by five kinds of behaviors. In particularly, the electromagnetic solitary wave for finite pulse laser is found beside the other four propagation cases including beam periodically oscillating with defocussing and focusing amplitude, constant spot size, beam catastrophic focusing. It is also found that the laser pulse can be allowed to propagate in the plasma channel only when a certain relation for laser parameters and plasma channel parameters is satisfied. For the solitary wave, it may provide an effective way to obtain ultra-short laser pulse.

  20. Quantification of optical pulsed-plane-wave-shaping by chiral sculptured thin films

    CERN Document Server

    Lakhtakia, A

    2006-01-01

    The durations and average speeds of ultrashort optical pulses transmitted through chiral sculptured thin films (STFs) were calculated using a finite-difference time-domain algorithm. Chiral STFs are a class of nanoengineered materials whose microstructure comprises parallel helicoidal nanowires grown normal to a substrate. The nanowires are $\\sim$10-300~nm in diameter and $\\sim1-10 \\mu$m in length. Durations of transmitted pulses tend to increase with decreasing (free-space) wavelength of the carrier plane wave, while average speeds tend to increase with increasing wavelength. An increase in nonlinearity, as manifested by an intensity-dependent refractive index in the frequency domain, tends to increase durations of transmitted pulses and decrease average speeds. The circular Bragg phenomenon exhibited by a chiral STFs manifests itself in the frequency domain as high reflectivity for normally incident carrier plane waves whose circular polarization state is matched to the structural handedness of the film and...

  1. Shock wave acceleration of protons in inhomogeneous plasma interacting with ultrashort intense laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Lecz, Zs. [ELI-ALPS, ELI-HU Nkft., Szeged (Hungary); Andreev, A. [ELI-ALPS, ELI-HU Nkft., Szeged (Hungary); Max-Born Institute, Berlin (Germany)

    2015-04-15

    The acceleration of protons, triggered by solitary waves in expanded solid targets is investigated using particle-in-cell simulations. The near-critical density plasma is irradiated by ultrashort high power laser pulses, which generate the solitary wave. The transformation of this soliton into a shock wave during propagation in plasma with exponentially decreasing density profile is described analytically, which allows to obtain a scaling law for the proton energy. The high quality proton bunch with small energy spread is produced by reflection from the shock-front. According to the 2D simulations, the mechanism is stable only if the laser pulse duration is shorter than the characteristic development time of the parasitic Weibel instability.

  2. Unidirectional Amplification and Shaping of Optical Pulses by Three-Wave Mixing with Negative Phonons

    CERN Document Server

    Popov, Alexander K; Myslivets, Sergey A; Slabko, Vitaly V

    2013-01-01

    A possibility to greatly enhance frequency-conversion efficiency of stimulated Raman scattering is shown by making use of extraordinary properties of three-wave mixing of ordinary and backward waves. Such processes are commonly attributed to negative-index plasmonic metamaterials. This work demonstrates the possibility to replace such metamaterials that are very challenging to engineer by readily available crystals which support elastic waves with contra-directed phase and group velocities. The main goal of this work is to investigate specific properties of indicated nonlinear optical process in short pulse regime and to show that it enables elimination of fundamental detrimental effect of fast damping of optical phonons on the process concerned. Among the applications is the possibility of creation of a family of unique photonic devices such as unidirectional Raman amplifiers and femtosecond pulse shapers with greatly improved operational properties.

  3. INFLUENCE OF PULSED SHORT WAVE (DIAPULSE TREATMENT ON THE BIOCHEMICAL PARAMETERS CORTISOL AND ALDOSTERONE

    Directory of Open Access Journals (Sweden)

    Dogaru Gabriela

    2015-12-01

    Full Text Available Pulsed short waves are part of high frequency therapy; unlike continuous short waves, where the phenomenon of tissular endothermia occurs, they have therapeutic effects that seem to depend rather on the interaction of electromagnetic waves with biological tissue, as they act only through specific electromagnetic energy. The recommended work technique for the use of the Diapulse device is that regardless of the exposed somatic region, there will be an initial exposure of one of the following regions: prehepatic, epigastric or lumbar (for action on the adrenal glands. Considering the role and the effects of the hormones of the adrenocortical gland, particularly glucocorticoids, on the body, which influence the inflammatory response of the connective tissue, with a role in rheumatoid pathology, we monitored the changes in the function of this gland. The biochemical parameters cortisol and aldosterone were quantitatively assessed in patients with complex regional pain syndrome type I (algoneurodystrophy treated with pulsed short waves, who were initially exposed to radiation of the lumbar region. In the same treatment session, all patients were exposed to radiation of the lumbar region, at a dose of 4/400 impulses/sec., for 10 minutes, followed by radiation of the affected region at a dose of 6/600 impulses/sec., for 10 minutes. There was one treatment session per day, for 14 days. It was demonstrated that radiation of the lumbar region at a dose of 4/400 impulses/sec. caused no changes in the hormonal function of the adrenal gland, i.e. no hypo- or hyperfunction; there was no overstrain or overstress after exposure to pulsed short waves, which is an important aspect, with applicability in clinical practice. Studies demonstrated both the local and the general, systemic influence of pulsed short waves, the induced changes being for the most part strictly dependent on the dose used.

  4. The performance of reflectometers at continuous wave and pulsed-neutron sources

    International Nuclear Information System (INIS)

    To quantify gains from time-of-flight (TOF) methods, identical reflectometers viewing a continuous wave (CW) neutron source and a variety of pulsed-neutron sources were simulated using a Monte Carlo technique. Reflectivity profiles obtained for a simple thin-film, reflecting,sample were nearly identical in all simulations, and models fitted to the simulated data yielded parameters (film thickness, surface roughness, and scattering length density) that were equally accurate and precise in all cases. The simulations confirm the power of the TOF method and demonstrate that the performance of pulsed sources for reflectometry does not scale simply as the inverse duty factor of the source. In the case of long-pulse sources, the simulations suggest that pulse tails have little effect on results obtained from specular reflectometry and that maximum brightness of the neutron source should be the primary design criterion

  5. The performance of reflectometers at continuous wave and pulsed-neutron sources

    International Nuclear Information System (INIS)

    To quantify gains from time-of-flight (TOF) methods, identical reflectometers viewing a continuous wave (CW) neutron source and a variety of pulsed-neutron sources were simulated using a Monte Carlo technique. Reflectivity profiles obtained for a simple thin-film, reflecting sample were nearly identical in all simulations, and models fitted to the simulated data yielded parameters (film thickness, surface roughness, and scattering length density) that were equally accurate and precise in all cases. The simulations confirm the power of the TOF method and demonstrate that the performance of pulsed sources for reflectometry does not scale simply as the inverse duty factor of the source. In the case of long-pulse sources, the simulations suggest that pulse tails have little effect on results obtained from specular reflectometry and that maximum brightness of the neutron source should be the primary design criterion. (author) 2 figs., 2 tabs., 5 refs

  6. Transformation of the Spatial Structure of an Optical Echo-Hologram Response by External Non-Resonant Pulses of Electromagnetic Standing Waves

    Science.gov (United States)

    Sakhbieva, A. R.; Nefed‧ev, L. A.; Garnaeva, G. I.

    2015-11-01

    It was shown that non-resonant electromagnetic standing wave pulses between exciting laser pulses during formation of a stimulated echo hologram transformed the wave front of the stimulated echo-hologram response.

  7. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    International Nuclear Information System (INIS)

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by “fresh” electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam

  8. Evaluation of arterial propagation velocity based on the automated analysis of the Pulse Wave Shape

    International Nuclear Information System (INIS)

    This paper proposes the automatic estimation of the arterial propagation velocity from the pulse wave raw records measured in the region of the radial artery. A fully automatic process is proposed to select and analyze typical pulse cycles from the raw data. An adaptive neuro-fuzzy inference system, together with a heuristic search is used to find a functional approximation of the pulse wave. The estimation of the propagation velocity is carried out via the analysis of the functional approximation obtained with the fuzzy model. The analysis of the pulse wave records with the proposed methodology showed small differences compared with the method used so far, based on a strong interaction with the user. To evaluate the proposed methodology, we estimated the propagation velocity in a population of healthy men from a wide range of ages. It has been found in these studies that propagation velocity increases linearly with age and it presents a considerable dispersion of values in healthy individuals. We conclude that this process could be used to evaluate indirectly the propagation velocity of the aorta, which is related to physiological age in healthy individuals and with the expectation of life in cardiovascular patients.

  9. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    Science.gov (United States)

    Ginzburg, N. S.; Zotova, I. V.; Sergeev, A. S.; Zaslavsky, V. Yu.; Zheleznov, I. V.; Samsonov, S. V.; Mishakin, S. V.

    2015-11-01

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by "fresh" electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam.

  10. Heart-Carotid Pulse Wave Velocity a Useful Index of Atherosclerosis in Chinese Hypertensive Patients.

    Science.gov (United States)

    Li, Chunyue; Xiong, Huahua; Pirbhulal, Sandeep; Wu, Dan; Li, Zhenzhou; Huang, Wenhua; Zhang, Heye; Wu, Wanqing

    2015-12-01

    This study was designed to investigate the relationship between heart-carotid pulse wave velocity (hcPWV) and carotid intima-media thickness (CIMT) in hypertensive patients, and also to examine the effect of pre-ejection period (PEP) on it. Doppler ultrasound device was used to measure CIMT in left common carotid artery. Hypertensive patients were divided into normal (n = 36, CIMT ≤0.8 mm) and thickened (n = 31, CIMT > 0.8 mm) group. Electrocardiogram R-wave-based carotid pulse wave velocity (rcPWV) and aortic valve-carotid pulse wave velocity (acPWV) were calculated as the ratio of the travel length to the pulse transit time with or without PEP, respectively. CIMT has significant relations with rcPWV (r = 0.611, P < 0.0001) and acPWV (r = 0.384, P = 0.033) in thickened group. Moreover, CIMT showed stronger correlation with rcPWV than with acPWV in thickened group. Furthermore, both acPWV and rcPWV were determinant factors of CIMT in thickened group, independent of clinical confounders including age, gender, smoking behavior, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, high-density lipoprotein cholesterol, antihypertensive medication, and plaque occurrence. However, similar results were not found in normal group. Since CIMT has been considered as an index of atherosclerosis, our results suggested that both rcPWV and acPWV could be useful indexes of atherosclerosis in thickened CIMT hypertensive patients. Additionally, if hcPWV is computed with heart-carotid pulse transit time, including PEP could improve the accuracy of atherosclerosis assessment in hypertensive patients. PMID:26705228

  11. A novel continuous cardiac output monitor based on pulse wave transit time.

    Science.gov (United States)

    Sugo, Yoshihiro; Ukawa, Teiji; Takeda, Sunao; Ishihara, Hironori; Kazama, Tomiei; Takeda, Junzo

    2010-01-01

    Monitoring cardiac output (CO) is important for the management of patient circulation in an operation room (OR) or intensive care unit (ICU). We assumed that the change in pulse wave transit time (PWTT) obtained from an electrocardiogram (ECG) and a pulse oximeter wave is correlated with the change in stroke volume (SV), from which CO is derived. The present study reports the verification of this hypothesis using a hemodynamic analysis theory and animal study. PWTT consists of a pre-ejection period (PEP), the pulse transit time through an elasticity artery (T(1)), and the pulse transit time through peripheral resistance arteries (T(2)). We assumed a consistent negative correlation between PWTT and SV under all conditions of varying circulatory dynamics. The equation for calculating SV from PWTT was derived based on the following procedures. 1. Approximating SV using a linear equation of PWTT. 2. The slope and y-intercept of the above equation were determined under consideration of vessel compliance (SV was divided by Pulse Pressure (PP)), animal type, and the inherent relationship between PP and PWTT. Animal study was performed to verify the above-mentioned assumption. The correlation coefficient of PWTT and SV became r = -0.710 (p 〈 0.001), and a good correlation was admitted. It has been confirmed that accurate continuous CO and SV measurement is only possible by monitoring regular clinical parameters (ECG, SpO2, and NIBP). PMID:21095971

  12. High resolution wavenumber analysis for investigation of arterial pulse wave propagation

    Science.gov (United States)

    Hasegawa, Hideyuki; Sato, Masakazu; Irie, Takasuke

    2016-07-01

    The propagation of the pulse wave along the artery is relatively fast (several m/s), and a high-temporal resolution is required to measure pulse wave velocity (PWV) in a regional segment of the artery. High-frame-rate ultrasound enables the measurement of the regional PWV. In analyses of wave propagation phenomena, the direction and propagation speed are generally identified in the frequency-wavenumber space using the two-dimensional Fourier transform. However, the wavelength of the pulse wave is very long (1 m at a propagation velocity of 10 m/s and a temporal frequency of 10 Hz) compared with a typical lateral field of view of 40 mm in ultrasound imaging. Therefore, PWV cannot be identified in the frequency-wavenumber space owing to the low resolution of the two-dimensional Fourier transform. In the present study, PWV was visualized in the wavenumber domain using phases of arterial wall acceleration waveforms measured by high-frame-rate ultrasound.

  13. Influence of laser-supported detonation waves on metal drilling with pulsed CO2 lasers

    International Nuclear Information System (INIS)

    Drilling of highly reflective metals in an ambient atmosphere with single TEA-CO2-laser pulses of fluences between 300 and 6000 J/cm2 is reported. The drilling process was investigated by measuring the time-resolved laser power reflected specularly from the targets during the interaction and by analyzing the craters produced. Experiments were performed in ambient air, argon, and helium. Target damage was found to be strongly influenced by a laser-supported detonation (LSD) wave in the ambient gas. If the laser fluence exceeded a material-dependent damage threshold (copper: 300 J/cm2), drilling occurred, but the efficiency was inversely related to the duration of the LSD wave. Efficient material removal is possible if the LSD wave can be dissipated within a small fraction of the laser pulse duration. This was achieved by small-F-number focusing of TEM00 laser pulses of 5-μs duration. Replacing the ambient air at the target by a gas of lower density results in a further significant reduction of LSD-wave lifetime, and a correlated increase of the drilling yield. On copper targets a maximum drilling yield of 10-5 cm3/J was observed in ambient helium at a laser fluence of 1 kJ/cm2

  14. Electromagnetic Pulse Generation by the Shock Wave of Explosion in the Ionosphere

    Science.gov (United States)

    Sorokin, V.; Sergeev, I.; Yaschenko, A.

    High-amplitude electric field pulses have been recorded during experiments with explosive injection in the ionosphere. Considerable electric field disturbances were observed in cases where the measurements were carried out near the same line of force of the geomagnetic field. Formation of the explosion shock wave electromagnetic field in the ionosphere is theoretically investigated. A shock wave arises in explosion - type active experiments and disasters of space engines at the ionospheric altitudes. A semi - empirical model of shock wave in the rarefied gas is constructed. This model enable to determine the spatial - temporal distribution of gas temperature, velocity, density and pressure between shock wave front and explosion product surface depend on the Mach number and the explosion altitude. In analyzing the electrodynamic processes accompanying the explosive injection it was assumed that their source is the electric current generated in a propagating shock wave. Electric current occurs by the ionosphere plasma perturbation in external magnetic field behind of the shock wave front. This current is a source of electromagnetic pulse in the ionospheric plasma with Pedersen and Hall conductivities. It is shown that the electromagnetic perturbation propagates along to the magnetic-field direction and has the form of an oscillating wave packet. The frequency of the wave packet decreases depends on time. Its characteristic group velocity, wave length, and frequency decrease depends on angle between the propagation direction and the external magnetic field. The characteristic frequency of oscillations varies from 0.1 - 10 Hz. The phase velocity decreases in the interval from 10 to 100 km/sec depends on distance from the source. As the angle increases, the oscillations disappear and the field propagates as a single-polarity pulse. Theoretical results have been compared with experimental data obtained by observations of electromagnetic phenomena during explosive

  15. On the pressure wave problem in liquid metal targets for pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    A liquid metal target for a pulsed spallation source was modelled on the computer to investigate the effect of the high instantaneous power deposition (60 KJ in 1 μs) on the pressure in the liquid and the resulting stress on the container. It was found that for the short pulse duration the resulting stress would be likely to exceed the allowable design stress for steels of the HT-9 type with low nickel content. Adding a small volume fraction of gas bubbles might be a way to suppress almost completely the generation of pressure waves. (author) 12 figs., 5 refs

  16. Pulsed current wave shaping with a transmission line by utilizing superposition of a forward and a backward voltage wave for fast capillary Z-pinch discharge

    International Nuclear Information System (INIS)

    By using a water transmission line, current wave shaping was demonstrated for a fast capillary Z-pinch discharge recombination soft x-ray laser study. The pulsed power system consists of a water capacitor, a gap switch, a transmission line, and a capillary plasma load. A voltage wave initiated at the water capacitor propagates toward the capillary load through the transmission line. Control of the pulse delay that occurred in the transmission line provides the superposition of the forward and the backward voltage waves effectively in order to perform current wave shaping with higher current amplitude and rapid current decay.

  17. Melting and shock wave creation in uranium oxide due to Coulomb explosion after a pulsed ionization

    International Nuclear Information System (INIS)

    By means of molecular dynamics simulations, we study the effects of pulsed ionization in uranium oxide (UO2), which occurs when UO2 is bombarded with swift ions or fission fragments. A general formula is developed to predict melting radius under various conditions due to electron stripping and Coulomb explosion (CE). A critical density model is suggested in which the melting volume is proportional to ionization period, if the period is above a critical value. The maximum melting radius depends on the time period of structural relaxation above the melting temperature, which increases with increasing initial substrate temperatures due to a lower heat dissipation rate. Furthermore, shock waves are observed to emit from CE core but the kinetic energy wave peak exists only in U sublattices. The absence of kinetic energy waves in O sublattices is explained by their relatively higher thermal vibration which cancels the work done from the compression waves

  18. Electronic excitation by short X-ray pulses: From quantum beats to wave packet revivals

    CERN Document Server

    Riviere, Paula; Rost, Jan M

    2011-01-01

    We propose a simple way to determine the periodicities of wave packets in quantum systems directly from the energy differences of the states involved. The resulting classical periods and revival times are more accurate than those obtained with the traditional expansion of the energies about the central quantum number n, especially when n is low. The latter type of wave packet motion occurs upon excitation of highly charged ions with short XUV or X-ray pulses. Moreover, we formulate the wave packet dynamics in such a form that it directly reveals the origin of phase shifts in the maxima of the autocorrelation function. This phenomenon, so far poorly understood since it is not prominent in the high n regime, becomes a dominant feature in low n wave packet dynamics.

  19. The Object Coordination Class Applied to Wave Pulses: Analyzing Student Reasoning in Wave Physics.

    Science.gov (United States)

    Wittmann, Michael C.

    2002-01-01

    Analyzes student responses to interview and written questions on wave physics using diSessa and Sherin's coordination class model which suggests that student use of specific reasoning resources is guided by possibly unconscious cues. (Author/MM)

  20. Generation of shock waves in dense plasmas by high-intensity laser pulses

    Directory of Open Access Journals (Sweden)

    Pasley John

    2015-06-01

    Full Text Available When intense short-pulse laser beams (I > 1022 W/m2, τ < 20 ps interact with high density plasmas, strong shock waves are launched. These shock waves may be generated by a range of processes, and the relative significance of the various mechanisms driving the formation of these shock waves is not well understood. It is challenging to obtain experimental data on shock waves near the focus of such intense laser–plasma interactions. The hydrodynamics of such interactions is, however, of great importance to fast ignition based inertial confinement fusion schemes as it places limits upon the time available for depositing energy in the compressed fuel, and thereby directly affects the laser requirements. In this manuscript we present the results of magnetohydrodynamic simulations showing the formation of shock waves under such conditions, driven by the j × B force and the thermal pressure gradient (where j is the current density and B the magnetic field strength. The time it takes for shock waves to form is evaluated over a wide range of material and current densities. It is shown that the formation of intense relativistic electron current driven shock waves and other related hydrodynamic phenomena may be expected over time scales of relevance to intense laser–plasma experiments and the fast ignition approach to inertial confinement fusion. A newly emerging technique for studying such interactions is also discussed. This approach is based upon Doppler spectroscopy and offers promise for investigating early time shock wave hydrodynamics launched by intense laser pulses.

  1. Signatures of tunneling and multiphoton ionization by short-laser pulses: The partial-wave distribution

    Science.gov (United States)

    Arbó, Diego G.; Lemell, Christoph; Burgdörfer, Joachim

    2015-09-01

    We analyze the two-dimensional angular momentum-energy distribution of electrons emitted from argon by short laser pulses. We identify characteristic features of both multiphoton and tunneling ionization in the partial-wave distribution for Keldysh parameters close to unity. We observe a remarkable degree of quantum-classical correspondence in the photoinization process which becomes even more pronounced after intensity averaging over the focal volume. We derive an energy-dependent cut-off for the highest angular momentum accessible within the framework of the strong-field approximation, which accurately reproduces the partial wave distributions found from solutions of the time-dependent Schrödinger equation.

  2. Generation of millimeter-wave sub-carrier optical pulse by using a Fabry-Perot interferometer

    Institute of Scientific and Technical Information of China (English)

    Qing Ye; Ronghui Qu; Zujie Fang

    2007-01-01

    A novel scheme is proposed to transform a Gaussian optical pulse to a millimeter-wave (mm-wave) frequency modulation pulse by using a Fabry-Perot interferometer (FPI) for radio-over-fiber (ROF) system.It is shown that modulation frequency of mm-wave is determined by the optical path of the Fabry-Perot (F-P) cavity, and amplitude decay time and energy transfer efficiency are related to the reflectivity of the F-P cavity mirror. The effect of pulse train extension on inter-symbol interference is also discussed.

  3. Millisecond polarized pulses in decameter-wave radiation from Jupiter and Sun

    International Nuclear Information System (INIS)

    A new approach is suggested to the problem of the theory of Jovian decametric radiation and physical conditions at the point of origin. This depends upon a comparison of the characteristics of fast pulse decametre-wave radio emission from both Jupiter and the Sun and invokes the deductive procedure which Sagan (1971) has called 'Propositional Calculus'. Fast polarized pulses in radiation from Jupiter and the Sun have been studied at fixed frequencies in the range 18 to 26 MHz with time resolutions from one to five msec; a number of similarities between the pulses from both sources have been noted. A comparison of some of the pulse characteristics is being made in order to decide whether or not they are sufficiently alike to be regarded as having a common mechanism of origin at both Jupiter and the Sun. From this 'decision' it is proposed to establish boundary conditions for theoretical study. Fast pulses in the Jupiter radiation are generally supposed to be a source phenomenon although their actual mechanism is not understood. The reasons for this are to some extent inferred rather than proven and so, to check the possible (if unlikely) role of the interplanetary medium, observations are also being made using the large 26 MHz array at the University of Florida to search for possible fast pulses in the radiation from the more distant source Taurus A. (Auth.)

  4. Generation of High-Repetition-Rate Pulse Trains through the Continuous-Wave Perturbed by a Weak Gaussian Pulse in an Optical Fiber

    International Nuclear Information System (INIS)

    A new means of generating all-optically high-repetition-rate pulse trains is proposed and numerically demonstrated in an optical fiber. Our numerical simulations show that, due to the modulation instability effect, the initial continuous-wave with a weak optical pulse instead of conventional weak sinusoidal modulation imposed on it can gradually evolve into high-repetition-rate pulse trains. However, the generated pulse trains take on different features from the conventional case in terms of their widths, intensities, intervals, numbers, and pedestals. (fundamental areas of phenomenology(including applications))

  5. Development of terahertz pulse wave diagnostics for a magnetized fusion plasma reactor

    International Nuclear Information System (INIS)

    Terahertz wave diagnostics have been developed for current and future high-temperature and high-density fusion plasma measurements. Since the combined system of a reflectometer and a delayometer requires a wide-band frequency source for the density profile measurements, a terahertz pulse is a possible candidate. A test system using terahertz time-domain spectroscopy has been constructed to develop the diagnostics. The system utilizes a femtosecond fiber laser as a pumping source and a bow-tie-type photoconductive antenna as a THz wave emitter. An output THz pulse with a frequency of up to 2 THz has been obtained. Some investigations involving measurement of the refractive index of a test material are performed, and the transmission dispersion effects of an optical fiber are determined. (author)

  6. Dual pulses for cavitation control in lithotripsy: Shock wave-bubble interactions and bioeffects

    Science.gov (United States)

    Sokolov, Dahlia L.

    2002-08-01

    Cavitation, the growth and collapse of gas/vapor bubbles, appears to play an important role in both stone comminution and tissue injury during shock wave lithotripsy, the clinical treatment in which focused, high amplitude shock pulses are used to comminute kidney stones. The goal of this research was to characterize in vitro cavitation activity and stone and cell damage in a novel system that uses converging dual pulses, produced by two identical, confocal lithotripters, to modify the cavitation field. The cavitation bubble dynamics were numerically calculated, and experiments were performed in a research electrohydraulic shock wave lithotripter to determine bubble size, lifetime, and pit depth created in aluminum foils by cavitation collapse. Furthermore, damage to model stones and to red blood cells was measured for both single and dual-pulses. A single shock pulse creates a ˜15 x 100 mm cloud of bubbles in water. The greatest cavitation activity and stone damage from single-pulses was found to occur 2 cm proximal to the geometric focus, F2, where the stone is normally aligned. Therefore, a 2 cm shift in stone alignment may potentially improve stone comminution and reduce tissue injury in clinical treatment. The dual-pulse lithotripter, on the other hand, generates a localized and intensified cavitation field that increased stone comminution efficiency at F2 by at least three times the maximum values achieved by single-pulses. At F2, acoustic pressure approximately doubled, as did bubble size, collapse time, and pit depth on foils. A significant reduction in comminution of stones suspended in glycerol indicates that cavitation activity, not the doubling of acoustic pressure, explains the increased comminution. On either side of F2, the second delayed pulse mitigated bubble collapse, resulting in little or no pitting on foils and reduced hemolysis, even when compared with single pulses. Numerical calculations of radial dynamics agreed with experimental findings

  7. Determination of Bosentan in Pharmaceutical Preparations by Linear Sweep, Square Wave and Differential Pulse Voltammetry Methods

    OpenAIRE

    Atila, Alptug; Yilmaz, Bilal

    2015-01-01

    In this study, simple, fast and reliable cyclic voltammetry (CV), linear sweep voltammetry (LSV), square wave voltammetry (SWV) and differential pulse voltammetry (DPV) methods were developed and validated for determination of bosentan in pharmaceutical preparations. The proposed methods were based on electrochemical oxidation of bosentan at platinum electrode in acetonitrile solution containing 0.1 M TBACIO4. The well-defined oxidation peak was observed at 1.21 V. The calibration curves were...

  8. A new flow co-culture system for studying mechanobiology effects of pulse flow waves

    OpenAIRE

    Scott-Drechsel, Devon; Su, Zhenbi; Hunter, Kendall; Li, Min; Shandas, Robin; Tan, Wei

    2012-01-01

    Artery stiffening is known as an important pathological change that precedes small vessel dysfunction, but underlying cellular mechanisms are still elusive. This paper reports the development of a flow co-culture system that imposes a range of arterial-like pulse flow waves, with similar mean flow rate but varied pulsatility controlled by upstream stiffness, onto a 3-D endothelial-smooth muscle cell co-culture. Computational fluid dynamics results identified a uniform flow area critical for c...

  9. Two-photon vibrational excitation of air by long-wave infrared laser pulses

    OpenAIRE

    Palastro, J. P.; Penano, J.; Johnson, L A; Hafizi, B.; Wahlstrand, J. K.; Milchberg, H. M.

    2016-01-01

    Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a two-photon transition. The absorptive, vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than, but quickly surpassing, the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanism of 3rd harmonic generation, providing an additional two-photon excitation channel, fundamental...

  10. Dynamics of multilevel molecules and pulse propagation beyond rotating wave approximation near two-photon resonance

    International Nuclear Information System (INIS)

    Dynamics of multilevel molecules and pulse propagation is studied near the two-photon resonance. We have found a strict solution of this problem beyond the rotating wave approximation. Our analytical solution is in close agreement with the strict numerical solution for the 4,4'-bis(dimethylamino) stilbene molecule. The compensation of the dynamical Stark shift is studied for fixed-in-space molecules. It is shown that the orientational disorder does not allow complete compensation of the dynamical Stark shift

  11. Measurement of Pulse Wave Velocity during Valsalva and Mueller Maneuvers by Whole Body Impedance Monitor

    Czech Academy of Sciences Publication Activity Database

    Matějková, M.; Vondra, Vlastimil; Halámek, Josef; Soukup, L.; Plešinger, Filip; Viščor, Ivo; Jurák, Pavel

    Vol. 41. Cambridge: Computing in Cardiology, 2014, s. 557-560. ISBN 978-1-4799-4346-3. [Computing in Cardiology 2014 /41./. Cambridge (US), 07.09.2014-10.09.2014] R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : plethysmography * pulse wave velocity * bioimpedance Subject RIV: FS - Medical Facilities ; Equipment

  12. Intima-Media Thickness and Pulse Wave Velocity in Hypertensive Adolescents

    OpenAIRE

    Gil, Tae Young; Sung, Choi Youn; Shim, Sung Shine; Hong, Young Mi

    2008-01-01

    Increased intima-media thickness (IMT) and pulse wave velocity (PWV) are noninvasive markers of early arterial wall alteration and are more widely used in adult clinical research. We investigated whether IMT and PWV are useful predictors of cardiovascular risk in hypertensive adolescents. Fifteen hypertensive adolescents (13-18 yr old, systolic BP ≥140 mmHg, diastolic BP ≥90 mmHg) and seventeen normotensive subjects were included. Height, weight, obesity index, body mass index (BMI), and fat ...

  13. Arterial pulse wave velocity, inflammatory markers, pathological GH and IGF states, cardiovascular and cerebrovascular disease

    OpenAIRE

    Graham, Michael R; Peter Evans; Bruce Davies; Baker, Julien S

    2008-01-01

    Michael R Graham1, Peter Evans2, Bruce Davies1, Julien S Baker11Health and Exercise Science Research Unit, Faculty of Health Sport and Science, University of Glamorgan, Pontypridd, Wales, United Kingdom; 2Royal Gwent Hospital, Newport, Gwent, United KingdomAbstract: Blood pressure (BP) measurements provide information regarding risk factors associated with cardiovascular disease, but only in a specific artery. Arterial stiffness (AS) can be determined by measurement of arterial pulse wave vel...

  14. Diode-pumped intracavity optical parametric oscillator in pulsed and continuous-wave operation

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Skettrup, Torben; Petersen, O.B.;

    2002-01-01

    An intracavity optical parametric oscillator is investigated in pulsed and continuous-wave operation. The intracavity optical parametric oscillator is based on Yb:YAG as the laser material and a periodically poled lithium niobate crystal as the nonlinear material. Tuneable idler output powers above...... 200 mW are obtained in both modes of operation with 13.5 W of incident diode pump power. The idler output was tuned in the wavelength range 3820-4570 nm....

  15. Temporal Skewness of Electromagnetic Pulsed Waves Propagating Through Random Media with Embedded Irregularity Slab

    Institute of Scientific and Technical Information of China (English)

    许正文; 吴健; 霍文平; 吴振森

    2003-01-01

    Electromagnetic pulsed waves can be distorted in the propagation through random media, and their energy dis tributions change along the leading and trailing edge of the waveform, which can be presented by the temporal skewness. The skewness presents asymmetry and is treated by the third-order temporal moment, in which an analytic solution for the two-frequency mutual coherence function is obtained recently. Then, transionospheric pulses are discussed in details. Both theoretical analysis and numerical computation indicate that the contri butions from scattering and dispersion of irregularities dominate over those of background, so the latter can be neglected in most cases. Also, the temporal skewness of a transionospheric pulse is negative and energy is shifted to the leading edge.

  16. Estimation of local pulse wave velocity using arterial diameter waveforms: Experimental validation in sheep

    International Nuclear Information System (INIS)

    Increased arterial stiffness is associated with an increased risk of cardiovascular events. Estimation of arterial stiffness using local pulse wave velocity (PWV) promises to be very useful for noninvasive diagnosis of arteriosclerosis. In this work we estimated in an instrumented sheep, the local aortic pulse wave velocity using two sonomicrometry diameter sensors (separated 7.5 cm) according to the transit time method (PWVTT) with a sampling rate of 4 KHz. We simultaneously measured aortic pressure in order to determine from pressure-diameter loops (PWVPDLoop), the true local aortic pulse wave velocity. A pneumatic cuff occluder was implanted in the aorta in order to compare both methods under a wide range of pressure levels. Mean pressure values ranged from 47 to 101 mmHg and mean proximal diameter values from 12.5. to 15.2 mm. There were no significant differences between PWVTT and PWVPDLoop values (451±43 vs. 447±48 cm/s, p = ns, paired t-test). Both methods correlated significantly (R = 0.81, p<0.05). The mean difference between both methods was only 4±29 cm/s, whereas the range of the limits of agreement (mean ± 2 standard deviation) was -61 to +53 cm/s, showing no trend. In conclusion, the diameter waveforms transit time method was found to allow an accurate and precise estimation of the local aortic PWV.

  17. Numerical studies of powerful terahertz pulse generation from a super-radiant surface wave oscillator

    International Nuclear Information System (INIS)

    The results of theoretical and numerical studies of coherent stimulated terahertz radiation from intense, subnanosecond electron beam are presented. The mechanism of terahertz pulse generation is associated with self-bunching of the beam and slippage of the wave over the whole electron flow. This so called Cherenkov super-radiance (SR) is used to propose a compact terahertz generator with high peak power. A large cross-section (overmoded), slow wave structure is designed to support the high power handling capability, and the mode competition is avoided by operating the device in the surface wave status. With 2.5 D particle-in-cell simulation, the 'hot' characteristics of the proposed super-radiant terahertz generator are investigated, and the numerical results show that the SR peak power could be further increased by optimizing the amplitude profile of electron pulse. Under the condition of 0.5 ns pulsewidth, 500 kV voltage, and 1.5 kA current, the 110 ps, 680 MW, and 0.14 THz SR pulse is achieved with a power efficiency of 90.67% in TM01 mode.

  18. Continuous blood pressure monitoring during exercise using pulse wave transit time measurement.

    Science.gov (United States)

    Lass, J; Meigas, K; Karai, D; Kattai, R; Kaik, J; Rossmann, M

    2004-01-01

    This paper gives an overview of a research, which is focused on the development of the convenient device for continuous non-invasive monitoring of arterial blood pressure. The blood pressure estimation method is based on a presumption that there is a singular relationship between the pulse wave propagation time in arterial system and blood pressure. The parameter used in this study is pulse wave transit time (PWTT). The measurement of PWTT involves the registration of two time markers, one of which is based on ECG R peak detection and another on the detection of pulse wave in peripheral arteries. The reliability of beat to beat systolic blood pressure calculation during physical exercise was the main focus for the current paper. Sixty-one subjects (healthy and hypertensive) were studied with the bicycle exercise test. As a result of current study it is shown that with the correct personal calibration it is possible to estimate the beat to beat systolic arterial blood pressure during the exercise with comparable accuracy to conventional noninvasive methods. PMID:17272172

  19. Micro-joule sub-10-fs VUV pulse generation by MW pump pulse using highly efficient chirped-four-wave mixing in hollow-core photonic crystal fibers

    CERN Document Server

    Im, Song-Jin

    2013-01-01

    We theoretically study chirped four-wave mixing for VUV pulse generation in hollow-core photonic crystal fibers. We predict the generation of sub-10-fs VUV pulses with energy of up to hundreds of microjoule by broad-band chirped idler pulses at 830 nm and MW pump pulses with narrow-band at 277 nm. MW pump could be desirable to reduce the complexity of the laser system or use a high repetition rate-laser system. The energy conversion efficiency from pump pulse to VUV pulse reaches to 30%. This generation can be realized in kagome-lattice hollow-core PCF filled with noble gas of high pressure with core-diameter less than 40 micrometers which would enable technically simple or highly efficient coupling to fundamental mode of the fiber.

  20. High-power Yb-doped continuous-wave and pulsed fibre lasers

    Indian Academy of Sciences (India)

    B N Upadhyaya

    2014-01-01

    High-power laser generation using Yb-doped double-clad fibres with conversion efficiencies in excess of 80% have attracted much attention during the last decade due to their inherent advantages in terms of very high efficiency, no misalignment due to in-built intracore fibre Bragg gratings, low thermal problems due to large surface to volume ratio, diffraction-limited beam quality, compactness, reliability and fibre-optic beam delivery. Yb-doped fibres can also provide a wide emission band from ∼1010 nm to ∼1170 nm, which makes it a versatile laser medium to realize continuous-wave (CW), Q-switched short pulse, and mode-locked ultrashort pulse generation for various applications. In this article, a review of Yb-doped CW and pulsed fibre lasers along with our study on self-pulsing dynamics in CW fibre lasers to find its role in high-power fibre laser development and the physical mechanisms involved in its generation has been described. A study on the generation of high-power CWfibre laser of 165Woutput power and generation of high peak power nanosecond pulses from acousto-optic Q-switched fibre laser has also been presented.

  1. Lifetime risk factors and arterial pulse wave velocity in adulthood: the cardiovascular risk in young Finns study.

    Science.gov (United States)

    Aatola, Heikki; Hutri-Kähönen, Nina; Juonala, Markus; Viikari, Jorma S A; Hulkkonen, Janne; Laitinen, Tomi; Taittonen, Leena; Lehtimäki, Terho; Raitakari, Olli T; Kähönen, Mika

    2010-03-01

    Limited and partly controversial data are available regarding the relationship of arterial pulse wave velocity and childhood cardiovascular risk factors. We studied how risk factors identified in childhood and adulthood predict pulse wave velocity assessed in adulthood. The study cohort consisted of 1691 white adults aged 30 to 45 years who had risk factor data available since childhood. Pulse wave velocity was assessed noninvasively by whole-body impedance cardiography. The number of conventional childhood and adulthood risk factors (extreme quintiles for low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, body mass index, and smoking) was directly associated with pulse wave velocity in adulthood (P=0.005 and P<0.0001, respectively). In multivariable regression analysis, independent predictors of pulse wave velocity were sex (P<0.0001), age (P<0.0001), childhood systolic blood pressure (P=0.002) and glucose (P=0.02), and adulthood systolic blood pressure (P<0.0001), insulin (P=0.0009), and triglycerides (P=0.003). Reduction in the number of risk factors (P<0.0001) and a favorable change in obesity status (P=0.0002) from childhood to adulthood were associated with lower pulse wave velocity in adulthood. Conventional risk factors in childhood and adulthood predict pulse wave velocity in adulthood. Favorable changes in risk factor and obesity status from childhood to adulthood are associated with lower pulse wave velocity in adulthood. These results support efforts for a reduction of conventional risk factors both in childhood and adulthood in the primary prevention of atherosclerosis. PMID:20083727

  2. Electron-nucleus scattering at small angles in the field of a pulsed laser wave

    Science.gov (United States)

    Lebed', A. A.

    2016-04-01

    We study scattering of an electron by a screened potential of a nucleus in the field of a pulsed laser wave at small scattering angles. The interaction of an electron with the field of a nucleus is considered in the first Born approximation. An external field of a pulsed laser is accounted accurately as a quasimonochromatic wave. Analytical expressions are obtained for the transition amplitude and the cross section of the considered process. Scattering kinematics is defined at the minimal value of a transferred momentum. In this case the cross section contains a peak near the preferred scattering direction. It is shown that the maximum value of the cross section is determined by both the initial-electron energy and the energy of an external-field photon. Thus, the cross section of electron-nucleus scattering in a pulsed laser field can exceed in two orders of magnitude the cross section in absence of an external field in the case of ultrarelativistic energies and external field of a free-electron laser with keV-order photon energy.

  3. Ceramics sintering process by millimeter-wave radiation and pulsed high current supply; Miri ha taidenjiha narabini pulse daidenryu inka ni yoru ceramics shoketsu process

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, S. [Osaka University, Osaka (Japan). Joining and Welding Research Institute

    1998-11-15

    Research on ceramics sintering by milimeter-wave range microwaves is briefly reviewed in conjunction with that by pulsed high current supply. Unique features of mm-wave sintering are demonstrated in comparison with sintering by electrical furnaces as well as by 2.45 GHz radiation. Studies on mm-wave sintering of Al{sub 2}O{sub 3}+ZrO{sub 2} composite and Si{sub 3}N{sub 4}, as well as of TiN + Cr{sub 2}N composite, which has been conducted at JWRI, Osaka University, are described. Sintering mechanism of mm-wave radiation and pulsed high current supply is discussed based on the electromagnetic phenomena within the powder particles and grain boundaries. (author)

  4. Feedback Interactions of Polymerized Actin with the Cell Membrane: Waves, Pulses, and Oscillations

    Science.gov (United States)

    Carlsson, Anders

    Polymerized filaments of the protein actin have crucial functions in cell migration, and in bending the cell membrane to drive endocytosis or the formation of protrusions. The nucleation and polymerization of actin filaments are controlled by upstream agents in the cell membrane, including nucleation-promoting factors (NPFs) that activate the Arp2/3 complex to form new branches on pre-existing filaments. But polymerized actin (F-actin) also feeds back on the assembly of NPFs. We explore the effects of the resulting feedback loop of F-actin and NPFs on two phenomena: actin pulses that drive endocytosis in yeast, and actin waves traveling along the membrane of several cell types. In our model of endocytosis in yeast, the actin network is grown explicitly in three dimensions, exerts a negative feedback interaction on localized patch of NPFs in the membrane, and bends the membrane by exerting a distribution of forces. This model explains observed actin and NPF pulse dynamics, and the effects of several interventions including i) NPF mutations, ii) inhibition of actin polymerization, and iii) deletion of a protein that allows F-actin to bend the cell membrane. The model predicts that mutation of the active region of an NPF will enhance the accumulation of that NPF, and we confirm this prediction by quantitative fluorescence microscopy. For actin waves, we treat a similar model, with NPFs distributed over a larger region of the cell membrane. This model naturally generates actin waves, and predicts a transition from wave behavior to spatially localized oscillations when NPFs are confined to a small region. We also predict a transition from waves to static polarization as the negative-feedback coupling between F-actin and the NPFs is reduced. Supported by NIGMS Grant R01 GM107667.

  5. Detection and Characterization of Flaws in Sprayed on Foam Insulation with Pulsed Terahertz Frequency Electromagnetic Waves

    Science.gov (United States)

    Winfree, William P.; Madaras, Eric I.

    2005-01-01

    The detection and repair of flaws such as voids and delaminations in the sprayed on foam insulation of the external tank reduces the probability of foam debris during shuttle ascent. The low density of sprayed on foam insulation along with it other physical properties makes detection of flaws difficult with conventional techniques. An emerging technology that has application for quantitative evaluation of flaws in the foam is pulsed electromagnetic waves at terahertz frequencies. The short wavelengths of these terahertz pulses make them ideal for imaging flaws in the foam. This paper examines the application of terahertz pulses for flaw detection in foam characteristic of the foam insulation of the external tank. Of particular interest is the detection of voids and delaminations, encapsulated in the foam or at the interface between the foam and a metal backing. The technique is shown to be capable of imaging small voids and delaminations through as much as 20 cm of foam. Methods for reducing the temporal responses of the terahertz pulses to improve flaw detection and yield quantitative characterizations of the size and location of the flaws are discussed.

  6. Two-photon vibrational excitation of air by long-wave infrared laser pulses

    Science.gov (United States)

    Palastro, J. P.; Peñano, J.; Johnson, L. A.; Hafizi, B.; Wahlstrand, J. K.; Milchberg, H. M.

    2016-08-01

    Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a two-photon transition. The absorptive vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than but quickly surpassing the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanism of third-harmonic generation, providing an additional two-photon excitation channel, fundamental + third harmonic. The original and emergent two-photon excitations drive the resonance exactly out of phase, causing spatial decay of the absorptive vibrational nonlinearity. This nearly eliminates two-photon vibrational absorption. Here we present simulations and analytical calculations demonstrating how these processes modify the ultrafast optical nonlinearity in air. The results reveal nonlinear optical phenomena unique to the LWIR regime of ultrashort pulse propagation in the atmosphere.

  7. Pulsed plane wave analytic solutions for generic shapes and the validation of Maxwell's equations solvers

    Science.gov (United States)

    Yarrow, Maurice; Vastano, John A.; Lomax, Harvard

    1992-01-01

    Generic shapes are subjected to pulsed plane waves of arbitrary shape. The resulting scattered electromagnetic fields are determined analytically. These fields are then computed efficiently at field locations for which numerically determined EM fields are required. Of particular interest are the pulsed waveform shapes typically utilized by radar systems. The results can be used to validate the accuracy of finite difference time domain Maxwell's equations solvers. A two-dimensional solver which is second- and fourth-order accurate in space and fourth-order accurate in time is examined. Dielectric media properties are modeled by a ramping technique which simplifies the associated gridding of body shapes. The attributes of the ramping technique are evaluated by comparison with the analytic solutions.

  8. Design of broadband transmission quarter-wave plates for polarization control of isolated attosecond pulses

    International Nuclear Information System (INIS)

    Using a standard Levenberg–Marquardt algorithm, broadband quarter-wave plates (QWPs) with bandwidth from 3 to 18 eV in the extreme ultraviolet (EUV) region were designed using aperiodic Mo/Si multilayers. By analyzing the design results of the Mo/Si multiayers with different bilayer numbers, we found that a Mo/Si multilayer with more bilayers can achieve broader phase control, but suffers from lower total throughput and a degree of circular polarization. In addition, the pulse broadenings caused by the group delay dispersions of the designed broadband QWPs were studied, and their layer distributions were investigated. The oscillating distribution of bilayer thickness in optimized multilayers was observed, which is considered to be the reason for forming the broadband phase control. Such broadband QWPs can be applied to generate a circularly polarized broadband EUV source, such as isolated attosecond pulse, directly from a linearly polarized source. (paper)

  9. Arterial pulse pressure amplification described by means of a nonlinear wave model: characterization of human aging

    Science.gov (United States)

    Alfonso, M.; Cymberknop, L.; Armentano, R.; Pessana, F.; Wray, S.; Legnani, W.

    2016-04-01

    The representation of blood pressure pulse as a combination of solitons captures many of the phenomena observed during its propagation along the systemic circulation. The aim of this work is to analyze the applicability of a compartmental model for propagation regarding the pressure pulse amplification associated with arterial aging. The model was applied to blood pressure waveforms that were synthesized using solitons, and then validated by waveforms obtained from individuals from differentiated age groups. Morphological changes were verified in the blood pressure waveform as a consequence of the aging process (i.e. due to the increase in arterial stiffness). These changes are the result of both a nonlinear interaction and the phenomena present in the propagation of nonlinear mechanic waves.

  10. Probe beam-free detection of terahertz wave by electroluminescence induced by intense THz pulse

    Science.gov (United States)

    Shin, J.; Jin, Z.; Nosaka, Y.; Nakazawa, T.; Kodama, R.

    2016-03-01

    Recently, a table-top fs laser system can generate MW terahertz (THz) pulse with its electric field higher than 100 kV/cm can be generated by several schemes. Such a strong THz field can directly drive electrons inside various materials. Here, we demonstrated a direct THz electric field detection method by measuring the electroluminescence induced by intense THz pulse inside commonly available light emitting diode. An intense THz wave obtained by the two-color laser scheme was focused onto LED along with an external DC bias to induce luminescence which we found proportional to the amplitude of the incident THz field. The scheme can be useful to realize a low-cost, probe-free THz detection and imaging system.

  11. Studies on an improved indigenous pressure wave generator and its testing with a pulse tube cooler

    Science.gov (United States)

    Jacob, S.; Karunanithi, R.; Narsimham, G. S. V. L.; Kranthi, J. Kumar; Damu, C.; Praveen, T.; Samir, M.; Mallappa, A.

    2014-01-01

    Earlier version of an indigenously developed Pressure Wave Generator (PWG) could not develop the necessary pressure ratio to satisfactorily operate a pulse tube cooler, largely due to high blow by losses in the piston cylinder seal gap and due to a few design deficiencies. Effect of different parameters like seal gap, piston diameter, piston stroke, moving mass and the piston back volume on the performance is studied analytically. Modifications were done to the PWG based on analysis and the performance is experimentally measured. A significant improvement in PWG performance is seen as a result of the modifications. The improved PWG is tested with the same pulse tube cooler but with different inertance tube configurations. A no load temperature of 130 K is achieved with an inertance tube configuration designed using Sage software. The delivered PV power is estimated to be 28.4 W which can produce a refrigeration of about 1 W at 80 K.

  12. Two-photon vibrational excitation of air by long-wave infrared laser pulses

    CERN Document Server

    Palastro, J P; Johnson, L A; Hafizi, B; Wahlstrand, J K; Milchberg, H M

    2016-01-01

    Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a two-photon transition. The absorptive, vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than, but quickly surpassing, the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanism of 3rd harmonic generation, providing an additional two-photon excitation channel, fundamental + 3rd harmonic. The original and emergent two-photon excitations drive the resonance exactly out of phase, causing spatial decay of the absorptive, vibrational nonlinearity. This nearly eliminates two-photon vibrational absorption. Here we present simulations and analytical calculations demonstrating how these processes modify the ultrafast optical nonlinearity in air. The results reveal nonlinear optical phenomena unique to the LWIR regime of ultrashort pulse propagation in atmosphere.

  13. Kinetic Monte Carlo simulations of travelling pulses and spiral waves in the lattice Lotka-Volterra model

    Science.gov (United States)

    Makeev, Alexei G.; Kurkina, Elena S.; Kevrekidis, Ioannis G.

    2012-06-01

    Kinetic Monte Carlo simulations are used to study the stochastic two-species Lotka-Volterra model on a square lattice. For certain values of the model parameters, the system constitutes an excitable medium: travelling pulses and rotating spiral waves can be excited. Stable solitary pulses travel with constant (modulo stochastic fluctuations) shape and speed along a periodic lattice. The spiral waves observed persist sometimes for hundreds of rotations, but they are ultimately unstable and break-up (because of fluctuations and interactions between neighboring fronts) giving rise to complex dynamic behavior in which numerous small spiral waves rotate and interact with each other. It is interesting that travelling pulses and spiral waves can be exhibited by the model even for completely immobile species, due to the non-local reaction kinetics.

  14. A method for localized computation of Pulse Wave Velocity in carotid structure.

    Science.gov (United States)

    Patil, Ravindra B; Krishnamoorthy, P; Sethuraman, Shriram

    2015-08-01

    Pulse Wave Velocity (PWV) promises to be a useful clinical marker for noninvasive diagnosis of atherosclerosis. This work demonstrates the ability to perform localized carotid PWV measurements from the distention waveform derived from the Radio Frequency (RF) ultrasound signal using a carotid phantom setup. The proposed system consists of low cost custom-built ultrasound probe and algorithms for envelope detection, arterial wall identification, echo tracking, distension waveform computation and PWV estimation. The method is proposed on a phantom data acquired using custom-built prototype non-imaging probe. The proposed approach is non-image based and can be seamlessly integrated into existing clinical ultrasound scanners. PMID:26736653

  15. Dissipative rogue wave generation in multiple-pulsing mode-locked fiber laser

    Science.gov (United States)

    Lecaplain, C.; Grelu, Ph; Soto-Crespo, J. M.; Akhmediev, N.

    2013-06-01

    Following the first experimental observation of a new mechanism leading to optical rogue wave (RW) formation briefly reported in Lecaplain et al (2012 Phys. Rev. Lett. 108 233901), we provide an extensive study of the experimental conditions under which these RWs can be detected. RWs originate from the nonlinear interactions of bunched chaotic pulses that propagate in a fiber laser cavity, and manifest as rare events of high optical intensity. The crucial influence of the electrical detection bandwidth is illustrated. We also clarify the observation of RWs with respect to other pulsating regimes, such as Q-switching instability, that also lead to L-shaped probability distribution functions.

  16. Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers

    International Nuclear Information System (INIS)

    We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs

  17. Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers

    Energy Technology Data Exchange (ETDEWEB)

    Zajnulina, M.; Giannone, D.; Haynes, R.; Roth, M. M. [innoFSPEC-VKS, Leibniz Institute for Astrophysics, An der Sternwarte 16, 14482 Potsdam (Germany); Böhm, M. [innoFSPEC-InFaSe, University of Potsdam, Am Mühlenberg 3, 14476 Golm (Germany); Blow, K. [Aston Institute of Photonic Technologies, Aston Triangle, Birmingham B4 7ET (United Kingdom); Rieznik, A. A. [Instituto Tecnologico de Buenos Aires and CONICET, Buenos Aires (Argentina)

    2015-10-15

    We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs.

  18. Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers.

    Science.gov (United States)

    Zajnulina, M; Böhm, M; Blow, K; Rieznik, A A; Giannone, D; Haynes, R; Roth, M M

    2015-10-01

    We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs. PMID:26520070

  19. Matched calorimetric loads for high power, long pulse millimeter-wave gyrotrons

    International Nuclear Information System (INIS)

    A compact matched load for high power gyrotron testing in ECRH plants for fusion research applications is in development, with the main goal of providing reflection-free absorption and fast calorimetric measurement of the millimeter-wave power, also at long pulse duration. It is based on the results of the tests at full power and pulse length (140 GHz, 0.5 MW, 0.5 s) on similar loads installed on the ECRH plant of the FTU Tokamak in Frascati. Basically, the load is made of an integrating sphere in copper, with the inner wall covered by plasma spray with a mixture of lossy ceramics, providing an average wall reflectivity in the order of 40%. Absorbing material degradation, small-scale and large-scale damage patterns, caused by fatigue and long-term exposure to high power mm-wave, have been analyzed in detail, with the aim of improving the performances in terms of power handling capability and energy extraction efficiency. Physical-chemical analyses, performed on the original and on the degraded absorbing material, showed the effects of the mm-wave exposure. Damage patterns were recognized as interference of multiple reflections inside the load, with radiation accumulation close to the entrance port, as confirmed by a detailed numerical analysis. Increase in power and energy deposition capabilities require improvements of the present design in different areas: - strategies for the mitigation of the different causes of non-homogeneous deposition; - use of different plasma-sprayed materials as mm-wave absorbers; - improved cooling channel geometry with increased heat transfer rate to the cooling medium, for achieving 1 MW-CW power capability. (authors)

  20. Research of the elastic waves generated by a pulse laser. Excitation mechanism of elastic waves and application to nondestructive testing; Pulse laser de reikishita danseiha ni kansuru kenkyu. Danseiha reiki no mechanism to hihakai kensa eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Cho, H.; Takemoto, M. [Aoyama Gakuin University, Tokyo (Japan). College of Science and Engineering

    1994-07-20

    A bulk wave is generated when a pulse laser is irradiated to the material, and the characteristics of a Young`s modulus and Poisson`s ratio can be nondestructively estimated from the bulk wave. The generation mechanism of laser ultrasonic waves must be first clarified for such application. In this paper, fundamental research was conducted to study the generation mechanism of the elastic waves excited by a Q-switched Nd-YAG laser, and the generation method and characteristics of Rayleigh waves. The following result was obtained. A bulk wave is generated by the disk-like adiabatic expansion near the surface if the laser power is small when a spot-shape pulse laser was irradiated. A bulk wave is generated by the thin disk-like adiabatic expansion beneath the surface due to the thermal diffusion in the depth direction of a base material when the laser power becomes large. Moreover, a bulk wave is generated by the impact force due to abrasion and plasma when the power becomes still larger. The information on the bulk wave characteristics and Rayleigh wave was also obtained. 25 refs., 15 figs., 1 tab.

  1. Arterial blood pressure measurement and pulse wave analysis—their role in enhancing cardiovascular assessment

    International Nuclear Information System (INIS)

    The most common method of clinical measurement of arterial blood pressure is by means of the cuff sphygmomanometer. This instrument has provided fundamental quantitative information on arterial pressure in individual subjects and in populations and facilitated estimation of cardiovascular risk related to levels of blood pressure obtained from the brachial cuff. Although the measurement is taken in a peripheral limb, the values are generally assumed to reflect the pressure throughout the arterial tree in large conduit arteries. Since the arterial pressure pulse becomes modified as it travels away from the heart towards the periphery, this is generally true for mean and diastolic pressure, but not for systolic pressure, and so pulse pressure. The relationship between central and peripheral pulse pressure depends on propagation characteristics of arteries. Hence, while the sphygmomanometer gives values of two single points on the pressure wave (systolic and diastolic pressure), there is additional information that can be obtained from the time-varying pulse waveform that enables an improved quantification of the systolic load on the heart and other central organs. This topical review will assess techniques of pressure measurement that relate to the use of the cuff sphygmomanometer and to the non-invasive registration and analysis of the peripheral and central arterial pressure waveform. Improved assessment of cardiovascular function in relation to treatment and management of high blood pressure will result from future developments in the indirect measurement of arterial blood pressure that involve the conventional cuff sphygmomanometer with the addition of information derived from the peripheral arterial pulse. (topical review)

  2. Arterial blood pressure measurement and pulse wave analysis--their role in enhancing cardiovascular assessment.

    Science.gov (United States)

    Avolio, Alberto P; Butlin, Mark; Walsh, Andrew

    2010-01-01

    The most common method of clinical measurement of arterial blood pressure is by means of the cuff sphygmomanometer. This instrument has provided fundamental quantitative information on arterial pressure in individual subjects and in populations and facilitated estimation of cardiovascular risk related to levels of blood pressure obtained from the brachial cuff. Although the measurement is taken in a peripheral limb, the values are generally assumed to reflect the pressure throughout the arterial tree in large conduit arteries. Since the arterial pressure pulse becomes modified as it travels away from the heart towards the periphery, this is generally true for mean and diastolic pressure, but not for systolic pressure, and so pulse pressure. The relationship between central and peripheral pulse pressure depends on propagation characteristics of arteries. Hence, while the sphygmomanometer gives values of two single points on the pressure wave (systolic and diastolic pressure), there is additional information that can be obtained from the time-varying pulse waveform that enables an improved quantification of the systolic load on the heart and other central organs. This topical review will assess techniques of pressure measurement that relate to the use of the cuff sphygmomanometer and to the non-invasive registration and analysis of the peripheral and central arterial pressure waveform. Improved assessment of cardiovascular function in relation to treatment and management of high blood pressure will result from future developments in the indirect measurement of arterial blood pressure that involve the conventional cuff sphygmomanometer with the addition of information derived from the peripheral arterial pulse. PMID:19940350

  3. Generation of spherical and cylindrical shock acoustic waves from optical breakdown in water, stimulated with femtosecond pulse

    CERN Document Server

    Potemkin, F V; Podshivalov, A A; Gordienko, V M

    2014-01-01

    Using shadow photography technique we have observed shock acoustic wave from optical breakdown, excited in water by tightly focused Cr:Forsterite femtosecond laser beam, and have found two different regimes of shock wave generation by varying only the energy of laser pulse. At low energies a single spherical shock wave is generated from laser beam waist, and its radius tends to saturation with energy increasing. At higher energies long laser filament in water is fired, that leads to the cylindrical shock wave generation, which longitude increases logarithmically with laser pulse energy. From shadow pictures we estimated maximal velocity in front or shock wave of 2300+/-150m/s and pressure of 1.0+/-0.1 GPa

  4. Human Heart Pulse Wave Responses Measured Simultaneously at Several Sensor Placements by Two MR-Compatible Fibre Optic Methods

    Directory of Open Access Journals (Sweden)

    Teemu Myllylä

    2012-01-01

    Full Text Available This paper presents experimental measurements conducted using two noninvasive fibre optic methods for detecting heart pulse waves in the human body. Both methods can be used in conjunction with magnetic resonance imaging (MRI. For comparison, the paper also performs an MRI-compatible electrocardiogram (ECG measurement. By the simultaneous use of different measurement methods, the propagation of pressure waves generated by each heart pulse can be sensed extensively in different areas of the human body and at different depths, for example, on the chest and forehead and at the fingertip. An accurate determination of a pulse wave allows calculating the pulse transit time (PTT of a particular heart pulse in different parts of the human body. This result can then be used to estimate the pulse wave velocity of blood flow in different places. Both measurement methods are realized using magnetic resonance-compatible fibres, which makes the methods applicable to the MRI environment. One of the developed sensors is an extraordinary accelerometer sensor, while the other one is a more common sensor based on photoplethysmography. All measurements, involving several test patients, were performed both inside and outside an MRI room. Measurements inside the MRI room were conducted using a 3-Tesla strength closed MRI scanner in the Department of Diagnostic Radiology at the Oulu University Hospital.

  5. Smart photoplethysmographic sensor for pulse wave registration at different vascular depths.

    Science.gov (United States)

    Leier, Mairo; Pilt, Kristjan; Karai, Deniss; Jervan, Gert

    2015-08-01

    The aim of this paper is to propose a smart optical sensor for cardiovascular activity monitoring at different tissue layers. Photoplethysmography (PPG) is a noninvasive optical technique for monitoring mainly blood volume changes in the examined tissue. However, different important physiological parameters, such as oxygen saturation, heart and breathing rate, dynamics of skin micro-circulation, vasomotion activity etc., can be extracted from the registered PPG signal. The developed sensor consists of 32 light emitting sources with four different wavelengths, which are located to the four different distances from four photo detectors. Compared to the existing sensors, the system enables to select the optimal LED (light emitting diode) and photo detector couple in order to obtain the pulse wave signal from the interested blood vessels with the highest possible signal to noise ratio. In this study, the designed PPG sensor was tested for the pulse wave registration from radial artery. The highest efficiency and signal to noise ratio was achieved using infrared LED (940 nm) and photo-diode pair. PMID:26736641

  6. Data Communications Using Guided Elastic Waves by Time Reversal Pulse Position Modulation: Experimental Study

    Directory of Open Access Journals (Sweden)

    Yujie Ying

    2013-07-01

    Full Text Available In this paper, we present and demonstrate a low complexity elastic wave signaling and reception method to achieve high data rate communication on dispersive solid elastic media, such as metal pipes, using piezoelectric transducers of PZT (lead zirconate titanate. Data communication is realized using pulse position modulation (PPM as the signaling method and the elastic medium as the communication channel. The communication system first transmits a small number of training pulses to probe the dispersive medium. The time-reversed probe signals are then utilized as the information carrying waveforms. Rapid timing acquisition of transmitted waveforms for demodulation over elastic medium is made possible by exploring the reciprocity property of guided elastic waves. The experimental tests were conducted using a National Instrument PXI system for waveform excitation and data acquisition. Data telemetry bit rates of 10 kbps, 20 kbps, 50 kbps and 100 kbps with the average bit error rates of 0, 5.75 × 10−4, 1.09 × 10−2 and 5.01 × 10−2, respectively, out of a total of 40, 000 transmitted bits were obtained when transmitting at the center frequency of 250 kHz and a 500 kHz bandwidth on steel pipe specimens. To emphasize the influence of time reversal, no complex processing techniques, such as adaptive channel equalization or error correction coding, were employed.

  7. On the Design of Passive Resonant Circuits to Measure Local Pulse Wave Velocity in a Stent.

    Science.gov (United States)

    Schächtele, Jonathan

    2016-06-01

    In-stent restenosis is a frequent complication after stent implantation. This article investigates the design of a passive sensor system to be integrated into a stent for the detection of an in-stent restenosis by measuring the local pulse wave velocity (PWV). The proposed system uses two resonant circuits consisting of a capacitive pressure sensor and a coil as transponders. The pressure sensors are located at the proximal and distal end of the stent. An alternating external magnetic field with a constant frequency is applied such that the resonance frequencies of the transponders cross the excitation frequency when the pulse wave passes. The time delay between the resonances at the transponders can be captured to obtain the PWV. A model for the measurement system and a correlation between transponder design parameters and minimal resolvable time delay are derived. This correlation is based on the criterion that the 3 dB bandwidth of the transponder resonances may not overlap in the measurement time interval. This correlation can be used to design and analyze a transponder system for the proposed measurement system. In an experiment, in which the pressure sensors have been emulated by varactor diodes, it could be shown that the model is valid and that the criterion is suitable. Finally, the relevant design parameters of the transponders have been identified and their limitations investigated. PMID:26800547

  8. One-dimensional computational model of pulse wave propagation in the human bronchial tree.

    Science.gov (United States)

    Clavica, Francesco; Alastruey, Jordi; Borlotti, Alessandra; Sherwin, Spencer J; Khir, Ashraf W

    2010-01-01

    Airflow in the respiratory system has been predominantly studied in rigid ducts. Three-dimensional simulations are computationally expensive. One-dimensional (1-D) modelling offers a good compromise between accuracy and computational cost. In this work we described the propagation of air pulse in a model of human airways using the 1-D equations of flow in compliant vessels. Seven generations of bifurcations, starting from the trachea, were studied. Peripheral airways (from the 8(th) to 23(rd) generation) were modelled using lumped parameter models. Peripheral resistance values for normal and emphysematous lungs were taken from the literature. An acceleration pulse, very short in time, was enforced at the inlet of trachea. The results suggest that compression (positive pressure peaks) and expansion (negative pressure peaks) waves are generated according to the reflection coefficients of the corresponding reflection sites (bifurcations and terminal reflections). Different values for peripheral bronchial resistance generate three different terminal reflections, all negative with different wave amplitudes. The sensitivity of the code to different peripheral resistances suggests that the 1-D formulation is a promising tool for a better understanding of the impact of disease on the velocity and pressure waveforms in the first generations of airway vessels. PMID:21096163

  9. Enhancement of Lamb Wave Imaging Resolution by Step Pulse Excitation and Prewarping

    Directory of Open Access Journals (Sweden)

    Shangchen Fu

    2015-01-01

    Full Text Available For the purpose of improving the damage localization accuracy, a prewarping technology is combined with step pulse excitation and this method is used in Lamb wave imaging of plate structures with adjacent damages. Based on the step pulse excitation, various narrowband or burst response can be derived by signal processing technology and this method provides flexibility for further prewarping approach. A narrowband signal warped with a preselected distance is then designed, and the dispersion in the response of this prewarping signal will be greatly reduced. However, in order to calculate the distance for prewarping, the first arrival needs to be estimated from the burst response. From the step-pulse response, narrowband responses at different central frequencies can be obtained, and by averaging peak-value time of their first arrivals, a more accurate estimation can be calculated. By using the prewarping method to the damage scattering signals before imaging, the imaging resolution of the delay-and-sum method can be highly enhanced. The experiment carried out in an aluminum plate with adjacent damages proves the efficiency of this method.

  10. Pulse wave detection method based on the bio-impedance of the wrist

    Science.gov (United States)

    He, Jianman; Wang, Mengjun; Li, Xiaoxia; Li, Gang; Lin, Ling

    2016-05-01

    The real-time monitoring of pulse rate can evaluate the heart health to some extent, and the measurement of bio-impedance has the potential in wearable health monitoring system. In this paper, an effective method, which contains self-balancing bridge, flexible electrode, and high-speed digital lock-in algorithm (DLIA) with over-sampling, was designed to detect the impedance pulse wave at the wrist. By applying the self-balancing bridge, the basic impedance can be compensated as much as possible, and the low amplitude of impedance variation related to heart pulse can be obtained more easily. And the flexible conductive rubber electrode used in our experiment is human-friendly. Besides, the over-sampling method and high-speed DLIA are used to enhance the effective resolution of the existing data sampled by analog to digital converter. With the high-speed data process and simple circuit above, this proposed method has the potential in wrist-band wearable systems and it can satisfy quests of small volume and low power consumption.

  11. Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor

    CERN Document Server

    Chen, Yi-Hsin; Löw, Robert; Pfau, Tilman

    2015-01-01

    We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns time scales. Combined with a third cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report [1] using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity...

  12. Effects of bee venom acupuncture on heart rate variability, pulse wave, and cerebral blood flow for types of Sasang Constitution

    Directory of Open Access Journals (Sweden)

    Lee Sang-min

    2009-03-01

    Full Text Available 1. Objectives: To evaluate effects of bee venom acupuncture on cardiovascular system and differences according to each constitution. 2. Methods: Heart rate variability, pulse wave and the velocity of cerebral blood flow were measured before bee venom acupuncture(BVA, right after and after 30 minuets, had been applied to 20 subjects. 3. Results: 1. BVA did not have effects on measurement variables of heart rate variability. 2. BVA had effects on pulse wave, showing total time, radial augmentation index up and height of percussion wave, time to percussion wave, sum of pulse pressure down. 3. BVA did not have effects on the cerebral blood flow velocity when considering not Sasang Constitution 4. Considering Sasang Constitution, BVA demonstrates different responses in time to preincisura wave, mean blood flow velocity, peak systolic velocity and end diastolic velocity. 4.Conclusion: From those results, the following conclusions are obtained. Cause BVA alters pulse wave and makes differences in the cerebral blood flow velocity according to Sasang Constitution. Various methods of BVA treatment are needed considering Sasang Constitution.

  13. Characteristics of ZnO nanostructures synthesized by sonochemical reaction: Effects of continuous and pulse waves

    Science.gov (United States)

    Widiyastuti, W.; Machmudah, Siti; Kusdianto, Nurtono, Tantular; Winardi, Sugeng

    2015-12-01

    Nanostructured ZnO was synthesized by a sonochemical reaction. Ultrasonic irradiation were set up in continuous, pulse in 3 seconds on and a second off (on:off=3:1), and pulse in 2 seconds on and a second off (on:off=2:1) wave modes for 1.5 hours. The characteristics of particles generated by these modes such as morphology, crystallinity, FTIR, photoluminescence, and photocatalytic activity to degrade methylene blue were compared. Zinc nitrate and ammonia water-based solutions were selected as chemicals without the addition of other surfactants. The morphology of the generated ZnO particles could be tuned from flower-like, needle- or hairy-like, and spherical structures by changing the mode of ultrasonic irradiation from continuous, on:off=3:1, and on:off=2:1 modes, respectively. The generated particles indicated that a wurtzite structure of ZnO in a hexagonal phase was formed. The crystalline sizes of particles generated in continuous, on:off=3:1, and on:off=2:1 modes were 28, 27, 24 nm. A similar position of reduction peak of FTIR in all samples indicated that no differences in particles chemical bonding characteristics. Photoluminescence intensity was also decreased with changes the wave mode from continuous to pulse. Photocatalytic activity was also evaluated resulting in particles synthesized by continuous mode had the highest methylene blue degradation degree following by on:off=3:1, and on:off=2:1 modes.

  14. Characteristics of ZnO nanostructures synthesized by sonochemical reaction: Effects of continuous and pulse waves

    Energy Technology Data Exchange (ETDEWEB)

    Widiyastuti, W., E-mail: widi@chem-eng.its.ac.id; Machmudah, Siti; Kusdianto,; Nurtono, Tantular; Winardi, Sugeng [Department of Chemical Engineering, Institut Teknologi Sepuluh Nopember, Kampus ITS Sukolilo Surabaya 60111 (Indonesia)

    2015-12-29

    Nanostructured ZnO was synthesized by a sonochemical reaction. Ultrasonic irradiation were set up in continuous, pulse in 3 seconds on and a second off (on:off=3:1), and pulse in 2 seconds on and a second off (on:off=2:1) wave modes for 1.5 hours. The characteristics of particles generated by these modes such as morphology, crystallinity, FTIR, photoluminescence, and photocatalytic activity to degrade methylene blue were compared. Zinc nitrate and ammonia water-based solutions were selected as chemicals without the addition of other surfactants. The morphology of the generated ZnO particles could be tuned from flower-like, needle- or hairy-like, and spherical structures by changing the mode of ultrasonic irradiation from continuous, on:off=3:1, and on:off=2:1 modes, respectively. The generated particles indicated that a wurtzite structure of ZnO in a hexagonal phase was formed. The crystalline sizes of particles generated in continuous, on:off=3:1, and on:off=2:1 modes were 28, 27, 24 nm. A similar position of reduction peak of FTIR in all samples indicated that no differences in particles chemical bonding characteristics. Photoluminescence intensity was also decreased with changes the wave mode from continuous to pulse. Photocatalytic activity was also evaluated resulting in particles synthesized by continuous mode had the highest methylene blue degradation degree following by on:off=3:1, and on:off=2:1 modes.

  15. Arterial pulse wave velocity, inflammatory markers, pathological GH and IGF states, cardiovascular and cerebrovascular disease

    Directory of Open Access Journals (Sweden)

    Michael R Graham

    2008-12-01

    Full Text Available Michael R Graham1, Peter Evans2, Bruce Davies1, Julien S Baker11Health and Exercise Science Research Unit, Faculty of Health Sport and Science, University of Glamorgan, Pontypridd, Wales, United Kingdom; 2Royal Gwent Hospital, Newport, Gwent, United KingdomAbstract: Blood pressure (BP measurements provide information regarding risk factors associated with cardiovascular disease, but only in a specific artery. Arterial stiffness (AS can be determined by measurement of arterial pulse wave velocity (APWV. Separate from any role as a surrogate marker, AS is an important determinant of pulse pressure, left ventricular function and coronary artery perfusion pressure. Proximal elastic arteries and peripheral muscular arteries respond differently to aging and to medication. Endogenous human growth hormone (hGH, secreted by the anterior pituitary, peaks during early adulthood, declining at 14% per decade. Levels of insulin-like growth factor-I (IGF-I are at their peak during late adolescence and decline throughout adulthood, mirror imaging GH. Arterial endothelial dysfunction, an accepted cause of increased APWV in GH deficiency (GHD is reversed by recombinant human (rh GH therapy, favorably influencing the risk for atherogenesis. APWV is a noninvasive method for measuring atherosclerotic and hypertensive vascular changes increases with age and atherosclerosis leading to increased systolic blood pressure and increased left ventricular hypertrophy. Aerobic exercise training increases arterial compliance and reduces systolic blood pressure. Whole body arterial compliance is lowered in strength-trained individuals. Homocysteine and C-reactive protein are two infl ammatory markers directly linked with arterial endothelial dysfunction. Reviews of GH in the somatopause have not been favorable and side effects of treatment have marred its use except in classical GHD. Is it possible that we should be assessing the combined effects of therapy with rhGH and rh

  16. Aortic distensibility measured by pulse-wave velocity is not modified in patients with Chagas' disease

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    Arteaga Edmundo

    2006-06-01

    Full Text Available Abstract Background Experimental studies demonstrate that infection with trypanosoma cruzi causes vasculitis. The inflammatory lesion process could hypothetically lead to decreased distensibility of large and small arteries in advanced Chagas' disease. We tested this hypothesis. Methods and results We evaluated carotid-femoral pulse-wave velocity (PWV in 53 Chagas' disease patients compared with 31 healthy volunteers (control group. The 53 patients were classified into 3 groups: 1 16 with indeterminate form of Chagas' disease; 2 18 with Chagas' disease, electrocardiographic abnormalities, and normal systolic function; 3 19 with Chagas' disease, systolic dysfunction, and mild-to-moderate congestive heart failure. No difference was noted between the 4 groups regarding carotid-femoral PWV (8.4 ± 1.1 vs 8.2 ± 1.5 vs 8.2 ± 1.4 vs 8.7 ± 1.6 m/s, P = 0.6 or pulse pressure (39.5 ± 7.6 vs 39.3 ± 8.1 vs 39.5 ± 7.4 vs 39.7 ± 6.9 mm Hg, P = 0.9. A positive, significant, similar correlation occurred between PWV and age in patients with Chagas' disease (r = 0.42, P = 0.002, in controls (r = 0.48, P = 0.006, and also between PWV and systolic blood pressure in both groups (patients with Chagas' disease, r = 0.38, P = 0.005; healthy subjects, r = 0.36, P = 0.043. Conclusion Carotid femoral pulse-wave velocity is not modified in patients with Chagas' disease, suggesting that elastic properties of large arteries are not affected in this disorder.

  17. Propagation of a strong x-ray pulse: Pulse compression, stimulated Raman scattering, amplified spontaneous emission, lasing without inversion, and four-wave mixing

    International Nuclear Information System (INIS)

    We study the compression of strong x-ray pulses from x-ray free-electron lasers (XFELs) propagating through the resonant medium of atomic argon. The simulations are based on the three-level model with the frequency of the incident x-ray pulse tuned in the 2p3/2-4s resonance. The pulse propagation is accompanied by the self-seeded stimulated resonant Raman scattering (SRRS). The SRRS starts from two channels of amplified spontaneous emission (ASE), 4s-2p3/2 and 3s-2p3/2, which form the extensive ringing pattern and widen the power spectrum. The produced seed field triggers the Stokes ASE channel 3s-2p3/2. The population inversion is quenched for longer propagation distances where the ASE is followed by the lasing without inversion (LWI), which amplifies the Stokes component. Both ASE and LWI reshape the input pulse: The compressed front part of the pulse (up to 100 as) is followed by the long tail of the ringing and beating between the pump and Stokes frequencies. The pump pulse also generates weaker Stokes and anti-Stokes fields caused by four-wave mixing. These four spectral bands have fine structures caused by the dynamical Stark effect. A slowdown of the XFEL pulse up to 78% of the speed of light in vacuum is found because of a large nonlinear refractive index.

  18. Uncertainty quantification of inflow boundary condition and proximal arterial stiffness coupled effect on pulse wave propagation in a vascular network

    CERN Document Server

    Brault, A; Lucor, D

    2016-01-01

    SUMMARY This work aims at quantifying the effect of inherent uncertainties from cardiac output on the sensitivity of a human compliant arterial network response based on stochastic simulations of a reduced-order pulse wave propagation model. A simple pulsatile output form is utilized to reproduce the most relevant cardiac features with a minimum number of parameters associated with left ventricle dynamics. Another source of critical uncertainty is the spatial heterogeneity of the aortic compliance which plays a key role in the propagation and damping of pulse waves generated at each cardiac cycle. A continuous representation of the aortic stiffness in the form of a generic random field of prescribed spatial correlation is then considered. Resorting to a stochastic sparse pseudospectral method, we investigate the spatial sensitivity of the pulse pressure and waves reflection magnitude with respect to the different model uncertainties. Results indicate that uncertainties related to the shape and magnitude of th...

  19. Shear wave velocity and attenuation from pulse-echo studies of Berea sandstone

    Energy Technology Data Exchange (ETDEWEB)

    Green, D.H. [Ohio Univ., Athens, OH (United States); Wang, H.F. [Univ. of Wisconsin, Madison, WI (United States)

    1994-06-10

    The pulse-echo spectral-ratio technique has been adapted to the determination of ultrasonic shear wave attenuation in sandstone at variable states of saturation and pressure. The method can measure shear attenuation coefficients in the range 0.5 dB/cm to 8 dB/cm to within {+-}0.5 dB/cm. For the Berea sandstone, this range corresponds to values of the shear quality factor (Q{sub s}) between 10 and 100. Spectra of Q{sub s} show that between 600 and 1100 kHz, Q{sub s} decreases with frequency, particularly at high pressures (up to 700 MPa). Ultrasonic shear wave attenuation in a 90% water-saturated sample was intermediate between that for dry samples and the relatively high attenuation in fully saturated rock. Strong pressure dependence is seen in the shear attenuation for all saturation states, indicating a dominant role of dissipation mechanisms operating within open and compliant cracks. Substantial shear attenuation remains at the highest effective pressure applied to the saturated sample, which may be due to a more {open_quotes}global{close_quotes} fluid-flow loss mechanism. Scattering losses, as described by weak scattering theories for compressional waves, do not appear to be dominant at these frequencies. 46 refs., 9 figs.

  20. Shear wave velocity and attenuation from pulse-echo studies of Berea sandstone

    Science.gov (United States)

    Green, Douglas H.; Wang, Herbert F.

    1994-06-01

    The pulse-echo spectral-ratio technique has been adapted to the determination of ultrasonic shear wave attenuation in sandstone at variable states of saturation and pressure. The method can measure shear attenuation coefficients in the range 0.5 dB/cm to 8 dB/cm to within +/- 0.5 dB/cm. For the Berea sandstone, this range corresponds to values of the shear quality factor Q(sub s) between 10 and 100. Spectra Q(sub s) show that between 600 and 1110 kHz, Q(sub s) decreases with frequency, particularly at high pressures (up to 70 MPa). Ultrasonic shear wave attenuation in a 90% water-saturated sample was intermediate between that for dry samples and the relatively high attenuation in fully saturated rock. Strong pressure dependence is seen in the shear attentuation for all saturation states, indicating a dominant role of dissipation mechanisms operating within open and compliant cracks. Substantial shear attenuation remains at the highest effective pressure applied to the saturated sample, which may be due to a more 'global' fluid-flow loss mechanism. Scattering losses as described by weak scattering theories for compressional waves, do not appear to be dominant at these frequencies.

  1. Non-triggered quantification of central and peripheral pulse-wave velocity

    Directory of Open Access Journals (Sweden)

    Langham Michael C

    2011-12-01

    Full Text Available Abstract Purpose Stiffening of the arteries results in increased pulse-wave velocity (PWV, the propagation velocity of the blood. Elevated aortic PWV has been shown to correlate with aging and atherosclerotic alterations. We extended a previous non-triggered projection-based cardiovascular MR method and demonstrate its feasibility by mapping the PWV of the aortic arch, thoraco-abdominal aorta and iliofemoral arteries in a cohort of healthy adults. Materials and Methods The proposed method "simultaneously" excites and collects a series of velocity-encoded projections at two arterial segments to estimate the wave-front velocity, which inherently probes the high-frequency component of the dynamic vessel wall modulus in response to oscillatory pressure waves. The regional PWVs were quantified in a small pilot study in healthy subjects (N = 10, age range 23 to 68 yrs at 3T. Results The projection-based method successfully time-resolved regional PWVs for 8-10 cardiac cycles without gating and demonstrated the feasibility of monitoring beat-to-beat changes in PWV resulting from heart rate irregularities. For dul-slice excitation the aliasing was negligible and did not interfere with PWV quantification. The aortic arch and thoracoabdominal aorta PWV were positively correlated with age (p Conclusion The PWV map of the arterial tree from ascending aorta to femoral arteries may provide additional insight into pathophysiology of vascular aging and atherosclerosis.

  2. Thermal wave propagation in the pulsed laser irradiation of media with thermal memory

    International Nuclear Information System (INIS)

    Complete text of publication follows. If a sample is exposed to the influence of laser radiation part of its energy is absorbed and converted in heat. The heat generated in this way is transferred through the sample as heat waves, resulting in various effects (so called photothermal effects). A large number of nondestructive diagnostic methods are based on recording of these effects. It is necessary to create a good model in order to understand and correctly describe the measured results of heat transfer in different media. In a certain number of materials and structures, such as complex biological materials, polymers, metals excited by very short laser pulses etc., the property of thermal memory has been experimentally observed. Starting with the hyperbolic equation that describes heat transfer processes of such media, in this paper has been developed a model of laser-excited heat waves propagation in order to enable application of photothermal techniques in characterization of these media. The cases of optically opaque and transparent samples are considered. The influence of various backings on photothermal waves has also been analyzed. The results are compared to the previous models

  3. Generation of thermo-acoustic waves from pulsed solar/IR radiation

    Science.gov (United States)

    Rahman, Aowabin

    Acoustic waves could potentially be used in a wide range of engineering applications; however, the high energy consumption in generating acoustic waves from electrical energy and the cost associated with the process limit the use of acoustic waves in industrial processes. Acoustic waves converted from solar radiation provide a feasible way of obtaining acoustic energy, without relying on conventional nonrenewable energy sources. One of the goals of this thesis project was to experimentally study the conversion of thermal to acoustic energy using pulsed radiation. The experiments were categorized into "indoor" and "outdoor" experiments, each with a separate experimental setup. The indoor experiments used an IR heater to power the thermo-acoustic lasers and were primarily aimed at studying the effect of various experimental parameters on the amplitude of sound waves in the low frequency range (below 130 Hz). The IR radiation was modulated externally using a chopper wheel and then impinged on a porous solid, which was housed inside a thermo-acoustic (TA) converter. A microphone located at a certain distance from the porous solid inside the TA converter detected the acoustic signals. The "outdoor" experiments, which were targeted at TA conversion at comparatively higher frequencies (in 200 Hz-3 kHz range) used solar energy to power the thermo-acoustic laser. The amplitudes (in RMS) of thermo-acoustic signals obtained in experiments using IR heater as radiation source were in the 80-100 dB range. The frequency of acoustic waves corresponded to the frequency of interceptions of the radiation beam by the chopper. The amplitudes of acoustic waves were influenced by several factors, including the chopping frequency, magnitude of radiation flux, type of porous material, length of porous material, external heating of the TA converter housing, location of microphone within the air column, and design of the TA converter. The time-dependent profile of the thermo-acoustic signals

  4. Ionospheric cusp flows pulsed by solar wind Alfvén waves

    Directory of Open Access Journals (Sweden)

    P. Prikryl

    Full Text Available Pulsed ionospheric flows (PIFs in the cusp foot-print have been observed by the SuperDARN radars with periods between a few minutes and several tens of minutes. PIFs are believed to be a consequence of the interplanetary magnetic field (IMF reconnection with the magnetospheric magnetic field on the dayside magnetopause, ionospheric signatures of flux transfer events (FTEs. The quasiperiodic PIFs are correlated with Alfvénic fluctuations observed in the upstream solar wind. It is concluded that on these occasions, the FTEs were driven by Alfvén waves coupling to the day-side magnetosphere. Case studies are presented in which the dawn-dusk component of the Alfvén wave electric field modulates the reconnection rate as evidenced by the radar observations of the ionospheric cusp flows. The arrival of the IMF southward turning at the magnetopause is determined from multipoint solar wind magnetic field and/or plasma measurements, assuming plane phase fronts in solar wind. The cross-correlation lag between the solar wind data and ground magnetograms that were obtained near the cusp footprint exceeded the estimated spacecraft-to-magnetopause propagation time by up to several minutes. The difference can account for and/or exceeds the Alfvén propagation time between the magnetopause and ionosphere. For the case of short period ( < 13 min PIFs, the onset times of the flow transients appear to be further delayed by at most a few more minutes after the IMF southward turning arrived at the magnetopause. For the case of long period (30 – 40 min PIFs, the observed additional delays were 10–20 min. We interpret the excess delay in terms of an intrinsic time scale for reconnection (Russell et al., 1997 which can be explained by the surface-wave induced magnetic reconnection mechanism (Uberoi et al., 1999. Here, surface waves with wavelengths larger than the thickness of the neutral layer induce a tearing-mode instability whose rise time explains the

  5. Effect of pulse-wave factors in Middle Aged Women by Mountain Cultivated Ginseng Pharmacopuncture Original Articles

    Directory of Open Access Journals (Sweden)

    Park Sang Wook

    2011-03-01

    Full Text Available Objectives: The aim of this experiment is to know about Effect of pulse-wave factors in Middle Aged Women by Mountain Cultivated Ginseng Pharmacopuncture. Methods: First 20 Middle Aged women are diagnosed by pulse diagnosis, and then Mountain Cultivated Ginseng Pharmacopuncture(1 injection 20cc were injected. 30 minutes later, pulse diagnosis again performed. As a result, method of one-group pretest-posttes design were used for evaluation. Results: T(Total pulse cycle time statistically significant increased on both left and right chon, kwan,cheok. T4 time statistically significant increased on both left and right chon, kwan, cheok. T4-T1/T indexs except left cheokmaek, Right cheokmaek observation area decreased significantly in four sites.Wm(indicating high pressure retention time indexs increased significantly in the five sites were observed except right chon maek. Conclusions: Effect of pulse-wave factors in Middle Aged Women by Mountain Cultivated Ginseng Pharmacopuncture increased T, T4, Wm and decreased T4-T1/T indexs. The results of this experiment,Mountain Cultivated Ginseng Pharmacopuncture induced to increase the Pulse-wave's stability and strength.

  6. Multi-wave ultrasonic Doppler method for measuring high flow-rates using staggered pulse intervals

    International Nuclear Information System (INIS)

    The ultrasonic pulsed Doppler method (UDM) can obtain a velocity profile along the path of an ultrasonic beam. However, the UDM measurement volume is relatively large and it is known that the measurement volume affects the measurement accuracy. In this study, the effect of the measurement volume on velocity and flow rate measurements is analytically and experimentally evaluated. The velocities measured using UDM are considered to be ensemble-averaged values over the measurement volume in order to analyze the velocity error due to the measurement volume, while the flow rates are calculated from the integration of the velocity profile across the pipe. The analytical results show that the channel width, i.e. the spatial resolution along the ultrasonic beam axis, rather than the ultrasonic beam diameter, strongly influences the flow rate measurement. To improve the accuracy of the flow rate, a novel method using a multi-wave ultrasonic transducer consisting of two piezo-electric elements with different basic frequencies is proposed to minimize the size of the measurement volume in the near-wall region of a pipe flow. The velocity profiles in the near-wall region are measured using an 8 MHz sensor with a small diameter, while those far from the transducer are measured using a hollow 2 MHz sensor in the multi-wave transducer. The applicability of the multi-wave transducer was experimentally investigated using the water flow-rate calibration facility at the National Institute of Advanced Industrial Science and Technology (AIST). As a result, the errors in the flow rate were found to be below  −1%, while the multi-wave method is shown to be particularly effective for measuring higher flow rates in a large-diameter pipe. (paper)

  7. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    DEFF Research Database (Denmark)

    Jung, Nikolai H; Delvendahl, Igor; Pechmann, Astrid;

    2012-01-01

    Transcranial magnetic stimulation (TMS) commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor...... hand area (M1-HAND), if the induced tissue current has a posterior-to-anterior (PA) or anterior-to-posterior (AP) direction. Here we tested whether similar direction-specific effects could be elicited in M1-HAND using TMS pulses with a half-sine wave configuration....

  8. Millimeter-wave circuits and pulse compression radar baseband/analog signal processing blocks in silicon processes

    OpenAIRE

    Parlak, Mehmet

    2012-01-01

    The power dissipation and cost of the next generation pulse radar beamforming systems needs to be reduced for the imaging and surveillance sensors. This research work aims at developing and innovating the next generation, mobile hand-held, high performance radar systems for outdoor surveillance applications, i.e. pedestrian detection sensor. Integrating the low cost millimeter-wave (mm-wave) imaging array platforms with advanced analog/ baseband signal processing on silicon is proposed for re...

  9. Three and four wave parametric interactions for ultrashort pulse generation in the ultraviolet, near and mid-infrared spectral range

    OpenAIRE

    Darginavičius, Julius

    2013-01-01

    In this thesis we investigated and developed three- and four-wave interaction-based frequency conversion methods for ultrashort pulse generation in the ultraviolet (UV), near and mid-infrared (IR) spectral ranges. In particular, efficient generation of Nd:glass laser harmonics was demonstrated experimentally, through noncollinear four-wave difference-frequency mixing in isotropic media. Also, broadband optical parametric amplification in the UV was investigated theoretically and achieved expe...

  10. Enhanced generation of VUV radiation by four-wave mixing in mercury using pulsed laser vaporization

    CERN Document Server

    Chenais, Sebastien; Philippet, Laurent; Castex, Marie-Claude

    2007-01-01

    The efficiency of a coherent VUV source at 125 nm, based on 2-photon resonant four-wave mixing in mercury vapor, has been enhanced by up to 2 orders of magnitude. This enhancement was obtained by locally heating a liquid Hg surface with a pulsed excimer laser, resulting in a high density vapor plume in which the nonlinear interaction occurred. Energies up to 5 μJ (1 kW peak power) have been achieved while keeping the overall Hg cell at room temperature, avoiding the use of a complex heat pipe. We have observed a strong saturation of the VUV yield when peak power densities of the fundamental beams exceed the GW/cm2 range, as well as a large intensity-dependant broadening (up to ~30 cm-1) of the two-photon resonance. The source has potential applications for high resolution interference lithography and photochemistry.

  11. High Definition Oscillometry: Non-invasive Blood Pressure Measurement and Pulse Wave Analysis.

    Science.gov (United States)

    Egner, Beate

    2015-01-01

    Non-invasive monitoring of blood pressure has become increasingly important in research. High-Definition Oscillometry (HDO) delivers not only accurate, reproducible and thus reliable blood pressure but also visualises the pulse waves on screen. This allows for on-screen feedback in real time on data validity but even more on additional parameters like systemic vascular resistance (SVR), stroke volume (SV), stroke volume variances (SVV), rhythm and dysrhythmia. Since complex information on drug effects are delivered within a short period of time, almost stress-free and visible in real time, it makes HDO a valuable technology in safety pharmacology and toxicology within a variety of fields like but not limited to cardiovascular, renal or metabolic research. PMID:26091643

  12. Central blood pressure assessment using 24-hour brachial pulse wave analysis

    Directory of Open Access Journals (Sweden)

    Muiesan ML

    2014-10-01

    Full Text Available Maria Lorenza Muiesan, Massimo Salvetti, Fabio Bertacchini, Claudia Agabiti-Rosei, Giulia Maruelli, Efrem Colonetti, Anna Paini Clinica Medica, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy Abstract: This review describes the use of central blood pressure (BP measurements during ambulatory monitoring, using noninvasive devices. The principles of measuring central BP by applanation tonometry and by oscillometry are reported, and information on device validation studies is described. The pathophysiological basis for the differences between brachial and aortic pressure is discussed. The currently available methods for central aortic pressure measurement are relatively accurate, and their use has important clinical implications, such as improving diagnostic and prognostic stratification of hypertension and providing a more accurate assessment of the effect of treatment on BP. Keywords: aortic blood pressure measurements, ambulatory monitoring, pulse wave analysis

  13. Evaluation of agreement between temporal series obtained from electrocardiogram and pulse wave.

    Science.gov (United States)

    Leikan, GM; Rossi, E.; Sanz, MCuadra; Delisle Rodríguez, D.; Mántaras, MC; Nicolet, J.; Zapata, D.; Lapyckyj, I.; Siri, L. Nicola; Perrone, MS

    2016-04-01

    Heart rate variability allows to study the cardiovascular autonomic nervous system modulation. Usually, this signal is obtained from the electrocardiogram (ECG). A simpler method for recording the pulse wave (PW) is by means of finger photoplethysmography (PPG), which also provides information about the duration of the cardiac cycle. In this study, the correlation and agreement between the time series of the intervals between heartbeats obtained from the ECG with those obtained from the PPG, were studied. Signals analyzed were obtained from young, healthy and resting subjects. For statistical analysis, the Pearson correlation coefficient and the Bland and Altman limits of agreement were used. Results show that the time series constructed from the PW would not replace the ones obtained from ECG.

  14. Nanosecond laser pulse induced stress waves enhanced magnetofection of human carcinoma cells in vitro

    International Nuclear Information System (INIS)

    We have developed a novel platform for efficient gene delivery into cells using magnetic force for pre-concentration of gene-magnetic nanoparticle complex on the surface of cells with subsequent nanosecond laser pulse for generation of stress waves in transfection chamber which is able to permeabilize cell membrane for the facilitated delivery of gene into the cell interior. Combination of these two physical factors increased the efficiency of three different human carcinoma cells transfection with plasmid coding green fluorescence protein from 43% to 67%, from 35% to 54%, and from 23% to 39%, for HeLa (cervical carcinoma), MCF-7 (breast carcinoma), and UCI-107 (ovarian carcinoma) cells, respectively, as compared with using only magnetofection. Proposed fast, simple, and efficient method may have far reaching applications for cancer gene therapy

  15. Nanosecond laser pulse induced stress waves enhanced magnetofection of human carcinoma cells in vitro

    Science.gov (United States)

    Durdík, Š.; Babincová, M.; Bergemann, C.; Babinec, P.

    2012-09-01

    We have developed a novel platform for efficient gene delivery into cells using magnetic force for pre-concentration of gene-magnetic nanoparticle complex on the surface of cells with subsequent nanosecond laser pulse for generation of stress waves in transfection chamber which is able to permeabilize cell membrane for the facilitated delivery of gene into the cell interior. Combination of these two physical factors increased the efficiency of three different human carcinoma cells transfection with plasmid coding green fluorescence protein from 43% to 67%, from 35% to 54%, and from 23% to 39%, for HeLa (cervical carcinoma), MCF-7 (breast carcinoma), and UCI-107 (ovarian carcinoma) cells, respectively, as compared with using only magnetofection. Proposed fast, simple, and efficient method may have far reaching applications for cancer gene therapy.

  16. Ethnic Differences in and Childhood Influences on Early Adult Pulse Wave Velocity

    Science.gov (United States)

    Silva, Maria J.; Molaodi, Oarabile R.; Enayat, Zinat E.; Cassidy, Aidan; Karamanos, Alexis; Read, Ursula M.; Faconti, Luca; Dall, Philippa; Stansfield, Ben; Harding, Seeromanie

    2016-01-01

    Early determinants of aortic stiffness as pulse wave velocity are poorly understood. We tested how factors measured twice previously in childhood in a multiethnic cohort study, particularly body mass, blood pressure, and objectively assessed physical activity affected aortic stiffness in young adults. Of 6643 London children, aged 11 to 13 years, from 51 schools in samples stratified by 6 ethnic groups with different cardiovascular risk, 4785 (72%) were seen again at aged 14 to 16 years. In 2013, 666 (97% of invited) took part in a young adult (21–23 years) pilot follow-up. With psychosocial and anthropometric measures, aortic stiffness and blood pressure were recorded via an upper arm calibrated Arteriograph device. In a subsample (n=334), physical activity was measured >5 days via the ActivPal. Unadjusted pulse wave velocities in black Caribbean and white UK young men were similar (mean±SD 7.9±0.3 versus 7.6±0.4 m/s) and lower in other groups at similar systolic pressures (120 mm Hg) and body mass (24.6 kg/m2). In fully adjusted regression models, independent of pressure effects, black Caribbean (higher body mass/waists), black African, and Indian young women had lower stiffness (by 0.5–0.8; 95% confidence interval, 0.1–1.1 m/s) than did white British women (6.9±0.2 m/s). Values were separately increased by age, pressure, powerful impacts from waist/height, time spent sedentary, and a reported racism effect (+0.3 m/s). Time walking at >100 steps/min was associated with reduced stiffness (Pracism) independently increase arterial stiffness, effects likely to increase with age. PMID:27141061

  17. Photon statistics of pulse-pumped four-wave mixing in fiber with weak signal injection

    Science.gov (United States)

    Nan-Nan, Liu; Yu-Hong, Liu; Jia-Min, Li; Xiao-Ying, Li

    2016-07-01

    We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental results show that the intensity correlation function of individual signal (idler) field decreases with the intensity of signal injection. After applying narrow band filter in signal (idler) band, the value of decreases from 1.9 ± 0.02 (1.9 ± 0.02) to 1.03 ± 0.02 (1.05 ± 0.02) when the intensity of signal injection varies from 0 to 120 photons/pulse. The results indicate that the photon statistics changes from Bose–Einstein distribution to Poisson distribution. We calculate the intensity correlation functions by using the multi-mode theory of four-wave mixing in fibers. The theoretical curves well fit the experimental results. Our investigation will be useful for mitigating the crosstalk between quantum and classical channels in a dense wavelength division multiplexing network. Project supported by the National Natural Science Foundation of China (Grant No. 11527808), the State Key Development Program for Basic Research of China (Grant No. 2014CB340103), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120032110055), the Natural Science Foundation of Tianjin, China (Grant No. 14JCQNJC02300), the Program for Changjiang Scholars and Innovative Research Team in University, China, and the Program of Introducing Talents of Discipline to Universities, China (Grant No. B07014).

  18. Theory of pulsed four-wave mixing in one-dimensional silicon photonic crystal slab waveguides

    Science.gov (United States)

    Lavdas, Spyros; Panoiu, Nicolae C.

    2016-03-01

    We present a comprehensive theoretical analysis and computational study of four-wave mixing (FWM) of optical pulses co-propagating in one-dimensional silicon photonic crystal waveguides (Si-PhCWGs). Our theoretical analysis describes a very general setup of the interacting optical pulses, namely we consider nondegenerate FWM in a configuration in which at each frequency there exists a superposition of guiding modes. We incorporate in our theoretical model all relevant linear optical effects, including waveguide loss, free-carrier (FC) dispersion and FC absorption, nonlinear optical effects such as self- and cross-phase modulation (SPM, XPM), two-photon absorption (TPA), and cross-absorption modulation (XAM), as well as the coupled dynamics of free-carriers FCs and optical field. In particular, our theoretical analysis based on the coupled-mode theory provides rigorously derived formulas for linear dispersion coefficients of the guiding modes, linear coupling coefficients between these modes, as well as the nonlinear waveguide coefficients describing SPM, XPM, TPA, XAM, and FWM. In addition, our theoretical analysis and numerical simulations reveal key differences between the characteristics of FWM in the slow- and fast-light regimes, which could potentially have important implications to the design of ultracompact active photonic devices.

  19. Serum Osteopontin Level Correlates with Carotid-Femoral Pulse Wave Velocity in Geriatric Persons

    Directory of Open Access Journals (Sweden)

    Chung-Jen Lee

    2014-01-01

    Full Text Available Osteopontin (OPN is involved in the regulation of vascular calcification processes. The aim of this study was to evaluate the relationship between fasting serum OPN concentration and carotid-femoral pulse wave velocity (cfPWV in geriatric persons. Fasting blood samples were obtained from 93 geriatric persons. cfPWV were performed by SphygmoCor system. Serum OPN levels were measured using a commercially available enzyme-linked immunosorbent assay. Geriatric adults who had diabetes (P=0.007 or dyslipidemia (P=0.029 had higher cfPWV levels than those without diabetes or dyslipidemia. The univariable linear regression analysis showed that age (P=0.002, waist circumference (P=0.048, body mass index (P=0.004, systolic blood pressure (P=0.001, diastolic blood pressure (P=0.036, pulse pressure (P=0.017, creatinine (P=0.002, and log-OPN level (P=0.001 were positively correlated with cfPWV levels, while the high-density lipoprotein cholesterol (HDL-cholesterol level (P=0.007 and glomerular filtration rate (P=0.001 were negatively correlated with cfPWV levels among the geriatric adults. Multivariable forward stepwise linear regression analysis of the significant variables also showed that log-OPN (β=0.233, R2=0.123, regression coefficient: 1.868, P=0.011 was still an independent predictor of cfPWV levels in geriatric persons.

  20. Low temperature phase barium borate: A new optical limiter in continuous wave and nano pulsed regime

    Science.gov (United States)

    Babeela, C.; Girisun, T. C. Sabari

    2015-11-01

    Low temperature phase barium borate was synthesized by hydrothermal method. XRD analysis confirms the formation of γ-BBO or hydrated barium polyborate (Ba3B6O9(OH)6) which crystallizes in monoclinic system in the P2/c space group. The molecular structure analysis shows the presence of dominant BO4 unit and the hydrated nature of material. γ-BBO exhibits sharp absorption edge at 202 nm and highly transparency in the UV-Visible-NIR region. The peak at 347 nm in the emission spectrum is due to the presence of self-trapped exciton. The third order nonlinear optical properties and limiting behavior of low temperature barium borate in both pulsed and continuous wave regime were studied. The effective 2PA absorption coefficient of γ-BBO under ns pulse excitation is estimated to be 0.38 × 10-10 m/W. The nonlinear absorption coefficient, refractive index and optical susceptibility of the material in cw regime were found to be in the order of 10-5 m W-1, 10-12 m2 W-1, 10-6 esu respectively. In both regimes, low temperature phase barium borate exhibits better optical limiting properties than high temperature phase β-BBO.

  1. Accessing properties of electron wave packets generated by attosecond pulse trains through time-dependent calculations

    International Nuclear Information System (INIS)

    We present a time-dependent method for calculating the energy-dependent atomic dipole phase that an electron acquires when it is ionized by the absorption of a single ultraviolet photon. Our approach exactly mirrors the method used to experimentally characterize a train of attosecond pulses. In both methods the total electron phase is measured (calculated) via a two-photon interference involving the absorption or emission of an additional infrared photon in the continuum. In our calculation we use a perfect (zero spectral phase) light field and so extract the atomic dipole phase directly from the electron wave packet. We calculate the atomic phase for argon, neon, and helium at low infrared intensities and compare them to previous perturbative calculations. At moderate infrared probe intensities, we find that that the dipole phase can still be reliably determined using two-photon interference, even when higher-order processes are non-negligible. We also show that a continuum structure, in this case a Cooper minimum in argon, significantly affects the probability for infrared absorption and emission over a range of energies around the minimum, even at low infrared intensities. We conclude that well-characterized attosecond pulse trains can be used to examine continuum structures in atoms and molecules

  2. Dynamic Behaviors of Materials under Ramp Wave Loading on Compact Pulsed Power Generators

    Science.gov (United States)

    Zhao, Jianheng; Luo, Binqiang; Wang, Guiji; Chong, Tao; Tan, Fuli; Liu, Cangli; Sun, Chengwei

    The technique using intense current to produce magnetic pressure provides a unique way to compress matter near isentrope to high density without obvious temperature increment, which is characterized as ramp wave loading, and firstly developed by Sandia in 1998. Firstly recent advances on compact pulsed power generators developed in our laboratory, such as CQ-4, CQ-3-MMAF and CQ-7 devices, are simply introduced here, which devoted to ramp wave loading from 50GPa to 200 GPa, and to ultrahigh-velocity flyer launching up to 30 km/s. And then, we show our progress in data processing methods and experiments of isentropic compression conducted on these devices mentioned above. The suitability of Gruneisen EOS and Vinet EOS are validated by isentropic experiments of tantalum, and the parameters of SCG constitutive equation of aluminum and copper are modified to give better prediction under isentropic compression. Phase transition of bismuth and tin are investigated under different initial temperatures, parameters of Helmholtz free energy and characteristic relaxation time in kinetic phase transition equation are calibrated. Supported by NNSF of China under Contract No.11327803 and 11176002

  3. Simulations of fast-wave current drive in pulsed and steady-state DEMO designs

    Science.gov (United States)

    Bilato, R.; Brambilla, M.; Fable, E.

    2014-11-01

    Electromagnetic waves in the ion-cyclotron (IC) range of frequencies are presently investigated as possible current drive (CD) systems in fusion reactors. Among many physical and technical issues, an accurate description of radio-frequency (RF) power absorption by fusion- born alpha particles is of special importance, since RF heating of these particles is not only detrimental for the CD efficiency, but might worsen the operative conditions by increasing their prompt losses. The capability of the full-wave TORIC code has been recently augmented to account for RF absorption by fusion-born alpha particles, calculated to all-orders in finite Larmor radius and with a realistic distribution function. Here, we present simulation with TORIC addressing the sensitivity of current drive efficiency on the design of a future reactor, in particular density and temperature profiles, magnetic field intensity, and plasma dimensions. For this purpose, we have investigated possible frequency windows for CD for two proposed versions of the DEMO reactor, namely its pulsed and its more ambitious steady-state design. The important role of the antenna for a realistic estimate of the CD efficiency is pointed out.

  4. Numerical assessment of time-domain methods for the estimation of local arterial pulse wave speed.

    Science.gov (United States)

    Alastruey, Jordi

    2011-03-15

    A local estimation of pulse wave speed c, an important predictor of cardiovascular events, can be obtained at arterial locations where simultaneous measurements of blood pressure (P) and velocity (U), arterial diameter (D) and U, flow rate (Q) and cross-sectional area (A), or P and D are available, using the PU-loop, sum-of-squares (∑(2)), lnDU-loop, QA-loop or new D(2)P-loop methods. Here, these methods were applied to estimate c from numerically generated P, U, D, Q and A waveforms using a visco-elastic one-dimensional model of the 55 larger human systemic arteries in normal conditions. Theoretical c were calculated from the parameters of the model. Estimates of c given by the loop methods were closer to theoretical values and more uniform within each arterial segment than those obtained using the ∑(2). The smaller differences between estimates and theoretical values were obtained using the D(2)P-loop method, with root-mean-square errors (RMSE) smaller than 0.18 ms(-1), followed by averaging the two c given by the PU- and lnDU-loops (RMSE elastic effects were small and nearby junctions were well-matched for forward-travelling waves. The ∑(2) performed better at proximal locations. PMID:21211799

  5. Non-invasive measurement of aortic pressure in patients: Comparing pulse wave analysis and applanation tonometry

    Directory of Open Access Journals (Sweden)

    M.U.R. Naidu

    2012-01-01

    Full Text Available Objective: The aim of the present study was to validate and compare novel methods to determine aortic blood pressure non-invasively based on Oscillometric Pulse Wave Velocity (PWV measurement using four limb-cuff pressure waveforms and two lead Electrocardiogram (ECG with a validated tonometric pulse wave analysis system in patients. Materials and Methods: After receiving the consent, in 49 patients with hypertension, coronary artery disease, diabetes mellitus, PWV, and central blood pressures were recorded in a randomised manner using both the oscillometric and tonometric devices. All recordings were performed 10 minutes after the patient lying comfortably in a noise-free temperature-controlled room. The test was performed between 09 am and 10 am after overnight fast. A minimum of three measurements were performed by the same skilled and trained operator. From the raw data obtained with two devices, software calculated the final vascular parameters. Results: A total of 49 patients (8 women and 41 men, of mean age 40.5 years (range: 19-81 years participated in the present study. After transforming the brachial pressures into aortic pressures, the correlation coefficient between the Aortic Systolic Pressure (ASP values obtained with two methods was 0.9796 (P<0.0001. The mean difference between ASP with two methods was 0.3 mm Hg. Similarly, Aortic Diastolic Pressure (ADP values obtained with two methods also correlated significantly with correlation coefficient of 0.9769 (P<0.0001. The mean difference of ADP was 0.2 mm Hg. In case of Aortic Pulse Pressure (APP, the mean difference was 0.1 mm Hg. All parameters of central aortic pressures obtained with two methods correlated significantly. Conclusion: The new method of transforming the Carotid Femoral PWV (cfPWV and brachial blood pressure values into aortic blood pressure values seems to be reasonably good. The significant correlation between the values obtained by tonometric device and

  6. Soliton-Like Pulses in Vertical Granular Chain Under Gravity: Particle-Like or Wave-Like?

    Institute of Scientific and Technical Information of China (English)

    XU Ai-Guo; HONG Jongbae

    2001-01-01

    We numerically study the propagation, reflection and collision of soliton-like pulses in the vertical granular chain under gravity. For the pure granular chain system, during the propagation and reflection processes at the fixed end, it behaves like a particle. When it is reflected at the free end, it behaves as neither particle-like nor wave-like.When the strengths of the two colliding soliton-like pulses are close, they collide just like particles. When their strengths are greatly different, they collide just like waves. For the soliton behavior in the collision process, from particle-like to wave-like, there is a critical value θC for the ratio θ of the strengths of the two initial pulses. For the two-layer granular chain, if the mass of the grains in the second layeris less than that in the first layer, the soliton-like pulse in the first layer usually excites about [1/m] soliton-like pulses in the second layer.``

  7. Pulse wave analysis in a 180-degree curved artery model: Implications under physiological and non-physiological inflows

    Science.gov (United States)

    Bulusu, Kartik V.; Plesniak, Michael W.

    2013-11-01

    Systolic and diastolic blood pressures, pulse pressures, and left ventricular hypertrophy contribute to cardiovascular risks. Increase of arterial stiffness due to aging and hypertension is an important factor in cardiovascular, chronic kidney and end-stage-renal-diseases. Pulse wave analysis (PWA) based on arterial pressure wave characteristics, is well established in clinical practice for evaluation of arterial distensibility and hypertension. The objective of our exploratory study in a rigid 180-degree curved artery model was to evaluate arterial pressure waveforms. Bend upstream conditions were measured using a two-component, two-dimensional, particle image velocimeter (2C-2D PIV). An ultrasonic transit-time flow meter and a catheter with a MEMS-based solid state pressure sensor, capable of measuring up to 20 harmonics of the observed pressure waveform, monitored flow conditions downstream of the bend. Our novel continuous wavelet transform algorithm (PIVlet 1.2), in addition to detecting coherent secondary flow structures is used to evaluate arterial pulse wave characteristics subjected to physiological and non-physiological inflows. Results of this study will elucidate the utility of wavelet transforms in arterial function evaluation and pulse wave speed. Supported by NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

  8. Transient and time-resolved four-wave mixing with collinear pump and probe pulses using the heterodyne technique

    DEFF Research Database (Denmark)

    Mecozzi, A.; Mørk, Jesper

    1998-01-01

    We review the recently proposed heterodyne technique for four-wave mixing experiments with collinear and co-polarized pulses. We discuss issues related to the parameters of the nonlinear dynamics of the sample that can be extracted by this technique....

  9. Energy-scalable temporal cleaning device for femtosecond laser pulses based on cross-polarized wave generation

    International Nuclear Information System (INIS)

    We report on a compact energy-scalable device for generating high-fidelity femtosecond laser pulses based on spatial filtering through a hollow-core fiber followed by a nonlinear crystal for cross polarized wave (XPW) generation. This versatile device is suited for temporal pulse cleaning over a wide range of input energies (from 0.1 to ≥10 mJ) and is successfully qualified on different ultrafast laser systems. Full characterization of the XPW output is presented. In particular, we demonstrate the generation of 1.6 mJ energy pulses starting from 11 mJ input pulse energy. The temporal contrast of the pulses is enhanced by more than 4 orders of magnitude. In addition, pulse shortening from 40 fs down to 15 fs Fourier-transform limit yields an overall peak-power transmission of up to 50%. This device not only serves as an integrated pulse contrast filter inside an ultrafast laser amplifier but also as a simple back-end solution for temporal post-compression of amplified pulses. (authors)

  10. Pulsed electromagnetic wave exposure induces ultrastructural damage and upregulated expression of heat shock protein 70 in the rat adenohypophysis.

    Science.gov (United States)

    Cheng, Kang; Ren, Dong-Qing; Yi, Jun; Zhou, Xiao-Guang; Yang, Wen-Qing; Chen, Yong-Bin; Li, Yong-Qiang; Huang, Xiao-Feng; Zeng, Gui-Ying

    2015-08-01

    The aim of the present study was to investigate the ultrastructural damage and the expression of heat shock protein 70 (HSP70) in the rat adenohypophysis following pulsed electromagnetic wave (PEMW) exposure. The rats were randomly divided into four groups: Sham PEMW exposure, 1 x 10(4) pulses of PEMW exposure, 1 x 10(5) pulses of PEMW exposure and 3 x 10(5) pulses of PEMW exposure. Whole body radiation of 1 x 10(4) pulses, 1 x 10(5) pulses and 3 x 10(5) pulses of PEMW were delivered with a field strength of 100 kV/m. The rats in each group (n=6 in each) were sacrificed 12, 24, 48 and 96 h after PEMW exposure. Transmission electron microscopy was then used to detect the ultrastructural changes and immunocytochemistry was used to examine the expression of HSP70. Cellular damage, including mitochondrial vacuolation occurred as early as 12 h after PEMW exposure.More severe cellular damages, including cell degeneration and necrosis, occurred 24 and 48 h after PEMW exposure. The PEMW-induced cellular damage increased as the number of PEMW pulses increased. In addition, the expression of HSP70 significantly increased following PEMW exposure and peaked after 12 h. These findings suggested that PEMW induced ultrastructural damages in the rat adenohypophysis and that HSP70 may have contributed to the PEMW-induced adenohypophyseal damage. PMID:25891763

  11. Whistler wave radiation from a pulsed loop antenna located in a cylindrical duct with enhanced plasma density

    Energy Technology Data Exchange (ETDEWEB)

    Kudrin, Alexander V.; Shkokova, Natalya M. [Department of Radiophysics, University of Nizhny Novgorod, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Ferencz, Orsolya E. [MTA Research Centre for Astronomy and Earth Sciences, Csatkai E. u. 6–8, Sopron H-9400 (Hungary); Zaboronkova, Tatyana M. [Department of Radiophysics, University of Nizhny Novgorod, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Department of Nuclear Physics, R. E. Alekseev State Technical University of Nizhny Novgorod, 24 Minin St., Nizhny Novgorod 603950 (Russian Federation)

    2014-11-15

    Pulsed radiation from a loop antenna located in a cylindrical duct with enhanced plasma density is studied. The radiated energy and its distribution over the spatial and frequency spectra of the excited waves are derived and analyzed as functions of the antenna and duct parameters. Numerical results referring to the case where the frequency spectrum of the antenna current is concentrated in the whistler range are reported. It is shown that under ionospheric conditions, the presence of an artificial duct with enhanced density can lead to a significant increase in the energy radiated from a pulsed loop antenna compared with the case where the same source is immersed in the surrounding uniform magnetoplasma. The results obtained can be useful in planning active ionospheric experiments with pulsed electromagnetic sources operated in the presence of artificial field-aligned plasma density irregularities that are capable of guiding whistler waves.

  12. Discharge conditions for CW and pulse-modulated surface-wave plasmas in low-temperature sterilization

    International Nuclear Information System (INIS)

    The discharge conditions required for low-temperature plasma sterilization were investigated using low-pressure surface-wave plasma (SWP). The discharge conditions for both continuous wave (CW) and pulse-modulated SWPs in low-temperature sterilization of Geobacillus stearothermophilus with a population of 1.5 x 106 and 3.0 x 106 were studied by varying the microwave input power from 500 W to 3 kW, and the effective plasma treatment time from 40 to 300 s. Results showed that sterilization was possible in a shorter treatment time using a higher microwave power for both CW and pulse-modulated SWPs. Pulse-modulated SWPs gave effective sterilization at a temperature roughly 10 to 20 deg. C below that of CW SWPs under the same average microwave power

  13. Multi-soliton, multi-breather and higher order rogue wave solutions to the complex short pulse equation

    Science.gov (United States)

    Ling, Liming; Feng, Bao-Feng; Zhu, Zuonong

    2016-07-01

    In the present paper, we are concerned with the general analytic solutions to the complex short pulse (CSP) equation including soliton, breather and rogue wave solutions. With the aid of a generalized Darboux transformation, we construct the N-bright soliton solution in a compact determinant form, the N-breather solution including the Akhmediev breather and a general higher order rogue wave solution. The first and second order rogue wave solutions are given explicitly and analyzed. The asymptotic analysis is performed rigorously for both the N-soliton and the N-breather solutions. All three forms of the analytical solutions admit either smoothed-, cusped- or looped-type ones for the CSP equation depending on the parameters. It is noted that, due to the reciprocal (hodograph) transformation, the rogue wave solution to the CSP equation can be a smoothed, cusponed or a looped one, which is different from the rogue wave solution found so far.

  14. Potential Role of Vegetarianism on Nutritional and Cardiovascular Status in Taiwanese Dialysis Patients: A Case-Control Study

    Science.gov (United States)

    Chen, Mei-Yin; Huang, Chien-Wei; Chen, Nai-Ching; Wu, Chien-Hsing; Hsu, Chih-Yang; Chou, Kang-Ju; Lee, Po-Tsang; Fang, Hua-Chang; Chen, Chien-Liang

    2016-01-01

    Background & Objectives Cardiovascular disease remains the most common cause of death for patients on chronic dialysis. End stage renal disease patients undergoing dialysis imposed to reduce phosphorus intake, which likely contributes to development of vegetarian diet behaviors. Vegetarian diets are often lower in protein content, in contradiction to the recommendation that a high protein diet is followed by patients undergoing dialysis. The purpose of the study was to investigate the effects of a vegetarian diet on the nutritional and cardiovascular status of dialysis patients. Design, Setting, Participants, Measurements A study of 21 vegetarian dialysis patients and 42 age- and sex-matched non-vegetarian dialysis patients selected as controls was conducted in the Kaohsiung Veterans General Hospital. Brachial-ankle pulse wave velocity and biochemistry data including total homocysteine levels, serum lipid profiles, high-sensitivity C-reactive protein, vitamin D levels, albumin, and normalized protein catabolic rate were measured. Results Compared with the non-vegetarian control group, vegetarian subjects had lower body weight, body mass index, serum phosphate, blood urea nitrogen, serum creatinine, vitamin D, uric acid, albumin, and normalized protein catabolic rate (p vegetarian group showed higher brachial-ankle pulse wave velocity than the non-vegetarian group (1926.95 ± 456.45 and 1684.82 ± 309.55 cm/sec, respectively, p vegetarian diet remained an independent risk factor for brachial-ankle pulse wave velocity. Conclusions The present study revealed that patients on dialysis who follow vegetarian diets may experience subclinical protein malnutrition and vitamin D deficiency that could offset the beneficial cardiovascular effects of vegetarianism. PMID:27295214

  15. Potential Role of Vegetarianism on Nutritional and Cardiovascular Status in Taiwanese Dialysis Patients: A Case-Control Study.

    Directory of Open Access Journals (Sweden)

    Shih-Hsiang Ou

    Full Text Available Cardiovascular disease remains the most common cause of death for patients on chronic dialysis. End stage renal disease patients undergoing dialysis imposed to reduce phosphorus intake, which likely contributes to development of vegetarian diet behaviors. Vegetarian diets are often lower in protein content, in contradiction to the recommendation that a high protein diet is followed by patients undergoing dialysis. The purpose of the study was to investigate the effects of a vegetarian diet on the nutritional and cardiovascular status of dialysis patients.A study of 21 vegetarian dialysis patients and 42 age- and sex-matched non-vegetarian dialysis patients selected as controls was conducted in the Kaohsiung Veterans General Hospital. Brachial-ankle pulse wave velocity and biochemistry data including total homocysteine levels, serum lipid profiles, high-sensitivity C-reactive protein, vitamin D levels, albumin, and normalized protein catabolic rate were measured.Compared with the non-vegetarian control group, vegetarian subjects had lower body weight, body mass index, serum phosphate, blood urea nitrogen, serum creatinine, vitamin D, uric acid, albumin, and normalized protein catabolic rate (p < 0.05. The vegetarian group showed higher brachial-ankle pulse wave velocity than the non-vegetarian group (1926.95 ± 456.45 and 1684.82 ± 309.55 cm/sec, respectively, p < 0.05. After adjustment for age, albumin, pre-dialysis systolic blood pressure, and duration of dialysis, vegetarian diet remained an independent risk factor for brachial-ankle pulse wave velocity.The present study revealed that patients on dialysis who follow vegetarian diets may experience subclinical protein malnutrition and vitamin D deficiency that could offset the beneficial cardiovascular effects of vegetarianism.

  16. Left ventricular radial colour and longitudinal pulsed-wave tissue Doppler echocardiography in 39 healthy domestic pet rabbits.

    Science.gov (United States)

    Casamian-Sorrosal, Domingo; Saunders, Richard; Browne, William; Elliot, Sarah; Fonfara, Sonja

    2014-10-01

    This paper reports radial colour and longitudinal mitral annulus pulsed-wave tissue Doppler findings in a large cohort of healthy, adult pet rabbits. Thirty-nine rabbits (22 Dwarf Lops, 14 French Lops and three Alaskans) underwent conscious echocardiography. The median age of the rabbits was 22 months and the median weight was 2.8 kg (Dwarf Lop 2.4 kg/French Lop 6.0 kg). Adequate radial colour and longitudinal pulsed-wave tissue Doppler traces were obtained in 100% and 85% of cases, respectively. Most systolic tissue Doppler parameters were significantly higher in French Lops than in Dwarf Lops. Separation of mitral inflow diastolic waves was present in 40% of cases using conventional spectral Doppler and in >60% of cases using pulsed-wave tissue Doppler which could be beneficial when evaluating diastolic function in rabbits. This study can be used as a reference for normal echocardiographic tissue Doppler values for adult rabbits undergoing conscious echocardiography in clinical practice. PMID:25089025

  17. An experimental study of the interaction between a pulsed electron beam and a large-amplitude electromagnetic wave

    Science.gov (United States)

    Kalinin, Yu. A.; Starodubov, A. V.; Fokin, A. S.

    2015-01-01

    We experimentally investigate the interaction between an electron beam with a periodically varying diameter and a large-amplitude electromagnetic wave. The effect of different factors on the pulsed beam formation and current density in bunches is established. Compared with the electron beam deceleration circuits (low-voltage vircator systems), the generators based on pulsed turbulent beams have a broader band due to the formation of a large number of space charge bunches and an integral power efficiency that is higher by a factor of 2-2.5.

  18. Multi-soliton, multi-breather and higher-order rogue wave solutions to the complex short pulse equation

    CERN Document Server

    Ling, Liming; Zhu, Zuonong

    2015-01-01

    In the present paper, we are concerned with the general localized solutions for the complex short pulse equation including soliton, breather and rogue wave solutions. With the aid of a generalized Darboux transformation, we construct the $N$-bright soliton solution in a compact determinant form, then the $N$-breather solution including the Akhmediev breather and a general higher order rogue wave solution. The first- and second-order rogue wave solutions are given explicitly and illustrated by graphs. The asymptotic analysis is performed rigorously for both the $N$-soliton and the $N$-breather solutions. All three forms of the localized solutions admit either smoothed-, cusped- or looped-type ones for the CSP equation depending on the parameters. It is noted that, due to the reciprocal (hodograph) transformation, the rogue wave solution to the CSP equation is different from the one to the nonlinear Schr\\"odinger (NLS) equation, which could be a cusponed- or a looped one.

  19. Relationship between non-dipper hypertension and arteriosclerosis in the elderly

    Institute of Scientific and Technical Information of China (English)

    陈策

    2014-01-01

    Objective To investigate the influence of non-dipper blood pressure rhythm on peripheral atherosclerosis in elderly hypertensive patients.Methods The 199 elderly hypertensive patients with 24-hour average systolic blood pressure<140 mmH g were selected.Body mass index(BMI),glycosylated hemoglobin,blood lipids,uric acid,creatinine,Brachial ankle pulse wave velocity(ba PWV),ankle arm index(ABI)and 24-hour ambulatory blood pressure monitoring were tested and calculated.The elderly patients were divided into dipper hypertensive group(n=95),and non-dipper hypertensive

  20. The Associations of Coping Mechanism with Arterial Stiffness in Hwa-Byung Patients

    OpenAIRE

    Lee, Yu Jin; Baek, Kyung Won; Yun, Kyu Wol; Lim, Wonshin; Lim, Weonjeong

    2009-01-01

    Objective The goal of this study is to assess the relationship between stress coping mechanisms and the risk of atherosclerosis in patients with Hwa-Byung. Methods The Korean version of the Ways of Coping Checklist (WOCC) was administered to 50 patients with Hwa-Byung (49.1±10.1 years, 6 males). Brachial-ankle pulse wave velocity (baPWV) and serum cholesterol level were assessed in all participants. Results After controlling for age, sex, diagnosis of hypertension, Body Mass Index (BMI), and ...

  1. Metabolic Syndrome-Associated Risk Factors and High-Sensitivity C-Reactive Protein Independently Predict Arterial stiffness in 9903 Subjects With and Without Chronic Kidney Disease

    OpenAIRE

    Tsai, Sung-Sheng; Lin, Yu-Sheng; Lin, Chia-Pin; Hwang, Jawl-Shan; Wu, Lung-Sheng; Chu, Pao-Hsien

    2015-01-01

    Abstract Metabolic syndrome (MS), high-sensitivity C-reactive protein (hs-CRP), and chronic kidney disease (CKD) are related to cardiovascular diseases. Although MS is common in CKD subjects, the contribution of MS-associated risk factors and hs-CRP to arterial stiffness in CKD has not been well studied. In this cross-sectional cohort study, we enrolled 9903 subjects who underwent brachial-ankle pulse wave velocity (baPWV) measurements from our database of Health Care Center. CKD was defined ...

  2. Impact of menaquinone-4 supplementation on coronary artery calcification and arterial stiffness: an open label single arm study

    OpenAIRE

    Ikari, Yuji; Torii, Sho; Shioi, Atsushi; Okano, Toshio

    2016-01-01

    Background Dietary intake of vitamin K has been reported to reduce coronary artery calcification (CAC) and cardiovascular events. However, it is unknown whether supplemental menaquinone (MK)-4 can reduce CAC or arterial stiffness. To study the effect of MK-4 supplementation on CAC and brachial ankle pulse wave velocity (baPWV). Methods This study is a single arm design to take 45 mg/day MK-4 daily as a therapeutic drug for 1 year. Primary endpoint was CAC score determined using 64-slice multi...

  3. A 1D pulse wave propagation model of the hemodynamics of calf muscle pump function.

    Science.gov (United States)

    Keijsers, J M T; Leguy, C A D; Huberts, W; Narracott, A J; Rittweger, J; van de Vosse, F N

    2015-07-01

    The calf muscle pump is a mechanism which increases venous return and thereby compensates for the fluid shift towards the lower body during standing. During a muscle contraction, the embedded deep veins collapse and venous return increases. In the subsequent relaxation phase, muscle perfusion increases due to increased perfusion pressure, as the proximal venous valves temporarily reduce the distal venous pressure (shielding). The superficial and deep veins are connected via perforators, which contain valves allowing flow in the superficial-to-deep direction. The aim of this study is to investigate and quantify the physiological mechanisms of the calf muscle pump, including the effect of venous valves, hydrostatic pressure, and the superficial venous system. Using a one-dimensional pulse wave propagation model, a muscle contraction is simulated by increasing the extravascular pressure in the deep venous segments. The hemodynamics are studied in three different configurations: a single artery-vein configuration with and without valves and a more detailed configuration including a superficial vein. Proximal venous valves increase effective venous return by 53% by preventing reflux. Furthermore, the proximal valves shielding function increases perfusion following contraction. Finally, the superficial system aids in maintaining the perfusion during the contraction phase and reduces the refilling time by 37%. PMID:25766693

  4. Multiscale entropy analysis of pulse wave velocity for assessing atherosclerosis in the aged and diabetic.

    Science.gov (United States)

    Wu, Hsien-Tsai; Hsu, Po-Chun; Lin, Cheng-Feng; Wang, Hou-Jun; Sun, Cheuk-Kwan; Liu, An-Bang; Lo, Men-Tzung; Tang, Chieh-Ju

    2011-10-01

    This study proposed a dynamic pulse wave velocity (PWV)-based biomedical parameter in assessing the degree of atherosclerosis for the aged and diabetic populations. Totally, 91 subjects were recruited from a single medical institution between July 2009 and October 2010. The subjects were divided into four groups: young healthy adults (Group 1, n = 22), healthy upper middle-aged adults (Group 2, n = 28), type 2 diabetics with satisfactory blood sugar control (Group 3, n = 21), and unsatisfactory blood sugar control (Group 4, n = 20). A self-developed six-channel electrocardiography (ECG)-PWV-based equipment was used to acquire 1000 successive recordings of PWV(foot) values within 30 min. The data, thus, obtained were analyzed with multiscale entropy (MSE). Large-scale MSE index (MEI(LS)) was chosen as the assessment parameter. Not only did MEI(LS) successfully differentiate between subjects in Groups 1 and 2, but it also showed a significant difference between Groups 3 and 4. Compared with the conventional parameter of PWV(foot) and MEI on R-R interval [i.e., MEI(RRI)] in evaluating the degree of atherosclerotic change, the dynamic parameter, MEI(LS) (PWV), could better reflect the impact of age and blood sugar control on the progression of atherosclerosis. PMID:21693413

  5. Generation of ultrasonic wave by a pulsed Nd:YAG laser and application of detection of defects

    International Nuclear Information System (INIS)

    Conventional ultrasonic evaluation is the contacting method by using transducer and couplant. Thus it not applied the material with high temperature, movement. Substitutionally a laser pulse irradiated on a material generates acoustic wave. In this paper, piezoelectric transducer detects ultrasonic waveforms. We have experimented in low laser energy for nondestructive evaluation. And theoretical waveform is compared with experimental waveform. And longitudinal, shear wave are detected and their sound velocity are obtained exactly. Also, in application, we discussed how flaw detection might be achieved with laser-generated ultrasound in aluminum plate with drill hole.

  6. Annihilation and creation of rotating waves by a local light pulse in a protoplasmic droplet of the Physarum plasmodium

    Science.gov (United States)

    Takagi, Seiji; Ueda, Tetsuo

    2010-06-01

    Pattern dynamics plays a fundamental role in biological functions from cell to organ in living systems, and the appearance of rotating waves can lead to pathological situations. Basic dynamics of rotating waves of contraction-relaxation activity under local perturbation is studied in a newly developed protoplasmic droplet of the Physarum plasmodium. A light pulse is applied by irradiating circularly a quarter of the droplet showing a single rotating wave. The oscillation pattern changes abruptly only when the irradiation is applied at a part of the droplet near the maximal contraction. The abrupt changes are as follows: the rotating wave disappears or is displaced when the irradiation area is very close to the center of the rotating wave, while new rotating waves are created when the irradiation area is far from the center of the rotating wave. These results support the hypothesis that the phase response curve has a discontinuous change (type 0 resetting) from delay to advance around the maximal contraction. The significance of the results is discussed in relation to “vulnerability” in excitable media and biological systems in general.

  7. The effect of low-intensity pulsed sound waves delivered by the Exogen device on Staphylococcus aureus morphology and genetics

    OpenAIRE

    Ayan, İrfan; ASLAN, Gönül; ÇÖMELEKOĞLU, Ülkü; Yılmaz, Nejat; ÇOLAK, Mehmet

    2004-01-01

    Objectives: We investigated the effect of low-intensity pulsed sound waves delivered by the Exogen device, which is recommended for the treatment of delayed union and nonunion in orthopedic surgery, on the colony number, antimicrobial susceptibility, bacterial morphology, and genetics of Staphylococcus aureus, which is a frequent pathogen in orthopedic infections. Methods: Thirty tubes containing 0.5 McFarland suspensions of S. aureus (ATCC 25923) were used. Fifteen tubes forming the test ...

  8. The Relationship among Pulse Wave Velocity, Ankle-Brachial Pressure Index and Heart Rate Variability in Adult Males

    OpenAIRE

    Ahn, Jeong-Hwan; Kong, Mihee

    2011-01-01

    Background Pulse wave velocity (PWV) and ankle-brachial pressure index (ABI) are non-invasive tools to measure atherosclerosis and arterial stiffness. Heart rate variability (HRV) has proven to be a non-invasive powerful tool in the investigation of the autonomic cardiovascular control. Therefore, the purpose of this study was to determine the relationship among PWV, ABI, and HRV parameters in adult males. Methods The study was carried out with 117 males who visited a health care center from ...

  9. Association of hypertension with physical factors of wrist pulse waves using a computational approach: a pilot study

    OpenAIRE

    Lee, Bum Ju; Jeon, Young Ju; Ku, Boncho; Kim, Jaeuk U.; Bae, Jang-Han; Kim, Jong Yeol

    2015-01-01

    Background The objectives of this pilot study were to examine the association between hypertension and physical factors of wrist pulse waves to avoid subjective diagnoses in Traditional Chinese Medicine (TCM) and Traditional Korean Medicine (TKM). An additional objective was to assess the predictive power of individual and combined physical factors in order to identify the degree of agreement between diagnosis accuracies using physical factors and using a sphygmomanometer in the prediction of...

  10. Neuro-fuzzy speed tracking control of traveling-wave ultrasonic motor drives using direct pulse width modulation

    OpenAIRE

    Chau, KT; Chung, SW

    2002-01-01

    The traveling-wave ultrasonic motor (TUSM) drive offers many distinct advantages but suffers from severe system nonlinearities and parameter variations especially during speed control. This paper presents a new speed tracking control system for the TUSM drive, which newly incorporates neuro-fuzzy control and direct pulse width modulation to solve the problem of nonlinearities and variations. Increasingly, the proposed control system is digitally implemented by a low-cost digital signal proces...

  11. Different photodynamic effect between continuous wave and pulsed laser irradiation modes in k562 cells in vitro

    International Nuclear Information System (INIS)

    Photodynamic therapy is a cancer treatment method is used primarily continuous mode laser radiation. At high power density irradiation occurs intense consumption of molecular oxygen and this caused hypoxic tumor tissue, which leads to inefficiency PDT. In this paper, pulsed and continuous irradiation modes during PDT photosensitizer Radachlorin were compared. A mathematical model for the generation of singlet oxygen 1O2 in tumor cells during photodynamic therapy with tissue oxygenation was developed. Our study theoretically and experimentally demonstrates the increased singlet oxygen generation efficiency in a pulsed irradiation mode compared to continuous wave mode with the same power density 20mW/cm2. Experimental in vitro showed that pulsed irradiation mode mostly induces apoptosis k562 tumor cells at irradiation doses of k562 1.25 – 2.5J/cm2 while the continuous mode induced necrosis

  12. Different photodynamic effect between continuous wave and pulsed laser irradiation modes in k562 cells in vitro

    Science.gov (United States)

    Klimenko, V. V.; Bogdanov, A. A.; Knyazev, N. A.; Rusanov, A. A.; Dubina, M. V.

    2014-10-01

    Photodynamic therapy is a cancer treatment method is used primarily continuous mode laser radiation. At high power density irradiation occurs intense consumption of molecular oxygen and this caused hypoxic tumor tissue, which leads to inefficiency PDT. In this paper, pulsed and continuous irradiation modes during PDT photosensitizer Radachlorin were compared. A mathematical model for the generation of singlet oxygen 1O2 in tumor cells during photodynamic therapy with tissue oxygenation was developed. Our study theoretically and experimentally demonstrates the increased singlet oxygen generation efficiency in a pulsed irradiation mode compared to continuous wave mode with the same power density 20mW/cm2. Experimental in vitro showed that pulsed irradiation mode mostly induces apoptosis k562 tumor cells at irradiation doses of k562 1.25 - 2.5J/cm2 while the continuous mode induced necrosis.

  13. The Marriage of Spectroscopy and Dynamics: Chirped-Pulse Fourier-Transform Mm-Wave Cp-Ft Spectroscopy in Pulsed Uniform Supersonic Flows

    Science.gov (United States)

    Abeysekera, Chamara; Oldham, James M.; Suits, Arthur G.; Park, G. Barratt; Field, Robert W.

    2012-06-01

    A new experimental scheme is presented that combines two powerful emerging technologies: chirped-pulse Fourier-transform mm-Wave spectroscopy and pulsed uniform supersonic flows. It promises a nearly universal detection method that can deliver quantitative isomer, conformer, and vibrational level specific detection, characterization of unstable reaction products and intermediates, and perform unique spectroscopic, kinetics, and dynamics measurements. Chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy, pioneered by Pate and coworkers, allows rapid acquisition of broadband microwave spectrum through advancements in waveform generation and oscilloscope technology. This revolutionary approach has successfully been adapted to higher frequencies by the Field group at MIT. Our new apparatus will exploit amplified chirped pulses in the range of 26-40 GHz, in combination with a pulsed uniform supersonic flow from a Laval nozzle. This nozzle source, pioneered by Rowe, Sims, and Smith for low temperature kinetics studies, produces thermalized reactants at high densities and low temperatures perfectly suitable for reaction dynamics experiments studied using the CP-mmW approach. This combination of techniques shall enhance the thousand-fold improvement in data acquisition rate achieved in the CP method by a further 2-3 orders of magnitude. A pulsed flow alleviates the challenges of continuous uniform flow, e.g. large gas loads and reactant consumption rates. In contrast to other pulsed Laval systems currently in use, we will use a fast piezo valve and small chambers to achieve the desired pressures while minimizing the gas load, so that a 10 Hz repetition rate can be achieved with one turbomolecular pump. The proposed technique will be suitable for many diverse fields, including fundamental studies in spectroscopy and reaction dynamics, reaction kinetics, combustion, atmospheric chemistry, and astrochemistry. We expect a significant advancement in the ability to

  14. Pulsed laser deposition of piezoelectric ZnO thin films for bulk acoustic wave devices

    Energy Technology Data Exchange (ETDEWEB)

    Serhane, Rafik, E-mail: rserhane@cdta.dz [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Abdelli-Messaci, Samira; Lafane, Slimane; Khales, Hammouche; Aouimeur, Walid [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Hassein-Bey, Abdelkadder [Centre for Development of Advanced Technologies, Cité 20 Août 1956, Baba Hassen, BP: 17, DZ-16303 Algiers (Algeria); Micro and Nano Physics Group, Faculty of Sciences, University Saad Dahlab of Blida (USDB), BP. 270, DZ-09000 Blida (Algeria); Boutkedjirt, Tarek [Equipe de Recherche Physique des Ultrasons, Faculté de Physique, Université des Sciences et de la Technologie Houari Boumediene (USTHB), BP 32, El-Alia, Bab-Ezzouar, DZ-16111 Algiers (Algeria)

    2014-01-01

    Piezoelectric properties of ZnO thin films have been investigated for micro-electro-mechanical systems (MEMS). Wurtzite ZnO structure was prepared on different substrates (Si (1 0 0), Pt (1 1 1)/Ti/SiO{sub 2}/Si and Al (1 1 1)/SiO{sub 2}/Si) at different substrate temperatures (from 100 to 500 °C) by a pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for various piezoelectric applications. Scanning electron microscopy (SEM) showed evidence of honeycomb-like structure on the surface and columnar structure on the cross-section. In the case of ZnO on Al, ZnO exhibited an amorphous phase at the ZnO/Al interface. The XRD measurements indicated that the substrate temperature of 300 °C was the optimum condition to obtain high quality (strongest (0 0 2) peak with the biggest associated grain size) of crystalline ZnO on Pt and on Al and that 400 °C was the optimum one on Si. ZnO on Al exhibits smallest rocking curve width than on Pt, leading to better crystalline quality. The ZnO films were used in bulk acoustic wave (BAW) transducer. Electrical measurements of the input impedance and S-Parameters showed evidence of piezoelectric response. The electromechanical coupling coefficient was evaluated as K{sub eff}{sup 2}=5.09%, with a quality factor Q{sub r} = 1001.4.

  15. Pulsed laser deposition of piezoelectric ZnO thin films for bulk acoustic wave devices

    International Nuclear Information System (INIS)

    Piezoelectric properties of ZnO thin films have been investigated for micro-electro-mechanical systems (MEMS). Wurtzite ZnO structure was prepared on different substrates (Si (1 0 0), Pt (1 1 1)/Ti/SiO2/Si and Al (1 1 1)/SiO2/Si) at different substrate temperatures (from 100 to 500 °C) by a pulsed laser deposition (PLD) technique. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for various piezoelectric applications. Scanning electron microscopy (SEM) showed evidence of honeycomb-like structure on the surface and columnar structure on the cross-section. In the case of ZnO on Al, ZnO exhibited an amorphous phase at the ZnO/Al interface. The XRD measurements indicated that the substrate temperature of 300 °C was the optimum condition to obtain high quality (strongest (0 0 2) peak with the biggest associated grain size) of crystalline ZnO on Pt and on Al and that 400 °C was the optimum one on Si. ZnO on Al exhibits smallest rocking curve width than on Pt, leading to better crystalline quality. The ZnO films were used in bulk acoustic wave (BAW) transducer. Electrical measurements of the input impedance and S-Parameters showed evidence of piezoelectric response. The electromechanical coupling coefficient was evaluated as Keff2=5.09%, with a quality factor Qr = 1001.4.

  16. Assessment of aortic pulse wave velocity by ultrasound: a feasibility study in mice

    Science.gov (United States)

    Faita, Francesco; Di Lascio, Nicole; Stea, Francesco; Kusmic, Claudia; Sicari, Rosa

    2014-03-01

    Pulse wave velocity (PWV) is considered a surrogate marker of arterial stiffness and could be useful for characterizing cardiovascular disease progression even in mouse models. Aim of this study was to develop an image process algorithm for assessing arterial PWV in mice using ultrasound (US) images only and test it on the evaluation of age-associated differences in abdominal aorta PWV (aaPWV). US scans were obtained from six adult (7 months) and six old (19 months) wild type male mice (strain C57BL6) under gaseous anaesthesia. For each mouse, diameter and flow velocity instantaneous values were achieved from abdominal aorta B-mode and PW-Doppler images; all measurements were obtained using edge detection and contour tracking techniques. Single-beat mean diameter and velocity were calculated and time-aligned, providing the lnD-V loop. aaPWV values were obtained from the slope of the linear part of the loop (the early systolic phase), while relative distension (relD) measurements were calculated from the mean diameter signal. aaPWV values for young mice (3.5±0.52 m/s) were lower than those obtained for older ones (5.12±0.98 m/s) while relD measurements were higher in young (25%±7%) compared with older animals evaluations (15%±3%). All measurements were significantly different between the two groups (P<0.01 both). In conclusion, the proposed image processing technique well discriminate between age groups. Since it provides PWV assessment just from US images, it could represent a simply and useful system for vascular stiffness evaluation at any arterial site in the mouse, even in preclinical small animal models.

  17. Pulse Wave Velocity and Cardiac Output vs. Heart Rate in Patients with an Implanted Pacemaker Based on Electric Impedance Method Measurement

    International Nuclear Information System (INIS)

    The methods and device for estimation of cardiac output and measurement of pulse wave velocity simultaneously is presented here. The beat-to-beat cardiac output as well as pulse wave velocity measurement is based on application of electrical impedance method on the thorax and calf. The results are demonstrated in a study of 24 subjects. The dependence of pulse wave velocity and cardiac output on heart rate during rest in patients with an implanted pacemaker was evaluated. The heart rate was changed by pacemaker programming while neither exercise nor drugs were applied. The most important result is that the pulse wave velocity, cardiac output and blood pressure do not depend significantly on heart rate, while the stroke volume is reciprocal proportionally to the heart rate.

  18. In vivo evaluation of a novel ‘diastole-patching’ algorithm for the estimation of pulse transit time: advancing the precision in pulse wave velocity measurement

    International Nuclear Information System (INIS)

    Carotid-to-femoral pulse wave velocity (PWV) is the gold standard for the assessment of aortic stiffness. It is calculated by the ratio of pulse transit time (PTT) between two arterial sites and the distance between them. The precision of PTT estimation depends upon the algorithm that determines characteristic points at the foot of the pulse waveforms. Different algorithms yield variable PTT values thus affecting the precision of PWV and subsequently its diagnostic and prognostic accuracy. Our aim was to apply in vivo a new ‘diastole-patching’ algorithm and investigate whether it improves the precision of PWV measurement. Two repeated PWV measurements were performed in a general population (340 subjects) by a reference apparatus (SphygmoCor) which uses the tangential method for PTT estimation. PTT was re-estimated by the ‘diastole-patching’ algorithm. We computed statistical parameters of agreement, consistency, precision and variability between the two PWV measurements. The ‘diastole-patching’ method yielded more precise and reproducible measurements of PWV compared to the tangential method at the total population. In those cases where the reference method provided PWV measurements with difference >1 m s−1, the ‘diastole-patching’ algorithm further improved the precision of PWV. These findings may have direct implications concerning the enhancement of the diagnostic and prognostic value of PWV. (paper)

  19. Exposure of the Thorax to a Sublethal Blast Wave Causes a Hydrodynamic Pulse That Leads to Perivenular Inflammation in the Brain

    OpenAIRE

    Simard, J. Marc; Pampori, Adam; Keledjian, Kaspar; Tosun, Cigdem; Schwartzbauer, Gary; Ivanova, Svetlana; Gerzanich, Volodymyr

    2014-01-01

    Traumatic brain injury (TBI) caused by an explosive blast (blast-TBI) is postulated to result, in part, from transvascular transmission to the brain of a hydrodynamic pulse (a.k.a., volumetric blood surge, ballistic pressure wave, hydrostatic shock, or hydraulic shock) induced in major intrathoracic blood vessels. This mechanism of blast-TBI has not been demonstrated directly. We tested the hypothesis that a blast wave impacting the thorax would induce a hydrodynamic pulse that would cause pa...

  20. Picosecond pulses of coherent MM-wave radiation in a photoinjector-driven waveguide free-selected laser

    Energy Technology Data Exchange (ETDEWEB)

    Fochs, S.N.; Le Sage, G.P.; Feng, L. [Univ. of California, Davis, CA (United States)] [and others

    1995-12-31

    A 5 MeV, high repetition rate (2.142 GHz in burst mode), high brightness, tabletop photoinjector is currently under construction at the UC Davis Department of Applied Science, on the LLNL site. Ultrashort pulses of coherent synchrotron radiation can be generated by transversally accelerating the electron beam with a wiggler in either metallic or dielectric-loaded waveguide FEL structures. This interaction is investigated theoretically and experimentally. Subpicosecond photoelectron bunches will be produced in the photoinjector by irradiating a high quantum efficiency Cs{sub 2}Te (Cesium Telluride) photocathode with a train of 100 UV (210 nm), ultra-short (250 fs) laser pulses. These bunches will be accelerated in a 1-1/2 cell {pi}-mode X-band RF gun e energized by a 20 MW, 8,568 GHz SLAC klystron. The peak current is 0.25 kA (0.25 nC, 1 ps), with a normalized beam emittance {epsilon}{sub n}<2.5 {pi} mm-mrad. This prebunched electron beam is then transversally accelerated in a cylindrical waveguide by a 30-mm period, 10 period long helical wiggler. The peak wiggler field is adjusted to 8.5 kG, so that the group velocity of the radiated electromagnetic waves matches the axial velocity of the electron bunch (grazing condition, zero slippage). Chirped output pulses in excess of 2 MW power are predicted, with an instantaneous bandwidth extending from 125 GHz to 225 GHz and a pulse duration of 15 ps (HWHM). To produce even shorter pulses, a dielectric-loaded waveguide can be used. The dispersion relation of this waveguide structure has an inflection point (zero group velocity dispersion). If the grazing condition is satisfied at this point, the final output pulse duration is no longer determined by slippage, or by group velocity dispersion and bandwidth, but by higher-order dispersive effects yielding transform-limited pulses.

  1. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    Directory of Open Access Journals (Sweden)

    Jung Nikolai H

    2012-11-01

    Full Text Available Abstract Background Transcranial magnetic stimulation (TMS commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor hand area (M1-HAND, if the induced tissue current has a posterior-to-anterior (PA or anterior-to-posterior (AP direction. Here we tested whether similar direction-specific effects could be elicited in M1-HAND using TMS pulses with a half-sine wave configuration. Results In 10 young participants, we applied half-sine pulses to the right M1-HAND which elicited PA or AP currents with respect to the orientation of the central sulcus. Measurements of the motor evoked potential (MEP revealed that PA half-sine stimulation resulted in lower resting motor threshold (RMT than AP stimulation. When stimulus intensity (SI was gradually increased as percentage of maximal stimulator output, the stimulus–response curve (SRC of MEP amplitude showed a leftward shift for PA as opposed to AP half-sine stimulation. Further, MEP latencies were approximately 1 ms shorter for PA relative to AP half-sine stimulation across the entire SI range tested. When adjusting SI to the respective RMT of PA and AP stimulation, the direction-specific differences in MEP latencies persisted, while the gain function of MEP amplitudes was comparable for PA and AP stimulation. Conclusions Using half-sine pulse configuration, single-pulse TMS elicits consistent direction-specific effects in M1-HAND that are similar to TMS with monophasic pulses. The longer MEP latency for AP half-sine stimulation suggests that PA and AP half-sine stimulation preferentially activates different sets of cortical neurons that are involved in the generation of different corticospinal descending volleys.

  2. High-power, mid-infrared, picosecond pulses generated by compression of a CO2 laser beat-wave in GaAs

    CERN Document Server

    Pigeon, J J; Joshi, C

    2015-01-01

    We report on the generation of a train of ~ 2 ps, 10 um laser pulses via multiple four-wave mixing and compression of an infrared laser beat-wave propagating in the negative group velocity dispersion region of bulk GaAs and a combination of GaAs and NaCl. The use of a 200 ps, 106 GHz beat-wave, produced by combining laser pulses amplified on the 10P(20) and 10P(16) transition of a CO2 laser, provides a novel method for generating high-power, picosecond, mid-IR laser pulses at a high repetition rate. By using 165 and 882 GHz beat-waves we show that cascaded phase-mismatched difference frequency generation plays a significant role in the four-wave mixing process in GaAs.

  3. Blast waves produced by interactions of femtosecond laser pulses with water

    International Nuclear Information System (INIS)

    The behaviors of the blast waves produced by femtosecond laser-water interactions, and the blast waves induced by laser self-focusing in air, have been investigated using optical shadowgraphy at a maximum intensity of 1x1016 W/cm2. The temporal evolution of the blast wave launched by the water plasma can be described by a planar blast wave model including source mass. An aneurismlike structure, due to the quick propagation inside a hollow channel formed by laser self-focusing, is observed. The expansion of the channel in air is found to agree with a cylindrical self-similar blast wave solution

  4. Evaluation of cellular effects of pulsed and continuous wave radiofrequency radiation

    International Nuclear Information System (INIS)

    Full text: In less than twenty years, the mobile telephone has gone from being rare, expensive equipment of the business elite to a pervasive, low-cost personal item. Since the introduction of mobile phones, concerns have been raised about the potential detrimental impacts on living beings from regular use. The first 'modern' network technology on second generation cellular technology was launched in 1991 in Finland on the Global System for Mobile Communications (GSM) standard. This study evaluates cellular effects of, both, continuous (CW) and pulsed GSM modulated waves (PW). Continuous cell culture of Chinese hamster lung cells, line V79, was used in this study. Cell growth and colony forming ability (CFA) was analyzed after 1, 2 and 3 hours of exposure to the both frequency fields, 935 MHz CW and 915 MHz PW. Selected frequency fields were generated inside gigahertz transversal electromagnetic mode cell (GTEM) equipped with the signal generators. Hewlett Packard HP8657A signal generator was used to generate CW 935 MHz frequency field. Anritzu MS2711B spectrum analyzer with tracking generator and Micro devices RF 3146 power amplifier module generated PW radiofrequency field of 915 MHz. Averaged specific absorption rate (SAR) belonging to the CW 935 MHz frequency field was calculated to be 0.12 W/kg, and for GSM modulated 915 MHz field was 0.23 W/kg. Cell samples were irradiated in triplicate. The sham exposed control cell samples were included in the study. The temperature inside the exposure set-up was recorded in ten-minute intervals through the irradiation treatment. Both, sham-exposed and exposed cell samples were kept in the same condition, except in the time of irradiation for experimental samples when signal generator was switched on. To determine cell growth, V79 samples were plated in concentration of 1x104cells/mL. Cells were maintained in the standard laboratory conditions, which are humidified atmosphere, 37 C degrees, and 5% CO2. Cell proliferation

  5. Effect of a pulsed Nd:YAG laser on surface acoustic wave velocity of human dental enamel

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the effect of Nd:YAG laser irradiation on the phase velocity of surface acoustic waves (SAWs) of human enamel. A pulsed Nd:YAG laser at 1064 nm wavelength was used to irradiate the human enamel from extracted human premolars. The output power and repetition rate were 250 mJ and 5 Hz, respectively. The SAW phase velocities before and after laser irradiation were determined using a laser photoacoustic method. The laser-treated enamel surface exhibited a higher velocity value for frequencies higher than 3 MHz. The result of this study suggests that there is an important correlation between the elastic properties of human enamel and the pulsed Nd:YAG laser fluence, which increases the SAW phase velocity, and this may help shed some light on the mechanism of laser treatment in dental research. (letter)

  6. Effect of isovolemic, isothermic hemodialysis on cerebral perfusion and vascular stiffness using contrast computed tomography and pulse wave velocity.

    Directory of Open Access Journals (Sweden)

    Ansgar Reising

    Full Text Available BACKGROUND: Patients undergoing hemodialysis treatment have a six-fold increased risk for stroke relative to the general population. However, the effect of hemodialysis on cerebral blood flow is poorly studied and confounding factors like blood pressure and ultrafiltration as well as temperature changes have rarely been accounted for. The aim of our study was to use state-of-the-art technology to evaluate the effect of a single dialysis session on cerebral perfusion as well as on vascular stiffness. METHODS: Chronic hemodialysis patients (7 male/3 female, mean age 58 years were recruited. Cerebral blood flow and arterial pulse wave velocity were measured before and immediately after a hemodialysis session. To exclude effects of volume changes we kept ultrafiltration to a minimum, allowing no change in body weight. Isothermic conditions were maintained by using the GENIUS single-pass batch-dialysis system with a high-flux polysulfone dialyser. Cerebral blood flow was measured by contrast-enhanced computed tomography. Pulse wave velocity was measured using the SphygmoCor (AtCor Medical, USA device by a single operator. RESULTS: This study shows for the first time that isovolemic, isothermic hemodialysis neither affected blood pressure or heart rate, nor total or regional cerebral perfusion. There was also no change in pulse wave velocity. CONCLUSIONS: Mechanisms other than the dialysis procedure itself might be causative for the high incidence of ischemic strokes in this patient population. Moreover, the sole removal of uremic toxins does not lead to short-term effects on vascular stiffness, underlying the importance of volume control in this patient population.

  7. Mechanistic investigation of doxycycline photosensitization by picosecond-pulsed and continuous wave laser irradiation of cells in culture

    Energy Technology Data Exchange (ETDEWEB)

    Shea, C.R.; Hefetz, Y.; Gillies, R.; Wimberly, J.; Dalickas, G.; Hasan, T. (Massachusetts General Hospital, Boston (USA))

    1990-04-15

    In order to elucidate the photophysical mechanisms of cellular phototoxicity sensitized by doxycycline, MGH-U1 human bladder carcinoma cells in vitro were treated with 20.7 microM doxycycline and irradiated with either a pulsed (lambda = 355 nm, pulse duration = 24 ps) or a continuous wave (lambda = 351 nm) laser. Cumulative radiant exposure and irradiance were systematically varied in experiments with both lasers. Phototoxicity was assessed by epifluorescence microscopy of unfixed cells using rhodamine 123 labeling of mitochondria. With the continuous wave source, the cumulative radiant exposure required for induction of phototoxic injury was independent of irradiance. With the 24-ps-pulsed source, a significantly lower cumulative radiant exposure was required to induce the phototoxicity when the peak irradiance was 5.8 x 10(7) or 1.3 x 10(8) watts cm-2 compared with when peak irradiance was either lower (6.0 x 10(6) watts cm-2) or higher (7.6 x 10(8) watts cm-2). The measured fluorescence lifetimes of doxycycline in buffered saline solution were longer than the laser pulse duration of 24 ps. The increased efficiency of photosensitization at the optimal peak irradiance in the ps domain appears to result from sequential multiphoton absorption involving higher excited states of the singlet manifold. At the highest irradiance studied, on the other hand, reduced efficiency of photosensitization is attributed to increased photodegradation of doxycycline from higher excited states by processes such as photoionization. A model consistent with these observations is presented along with calculations, based on simple rate equations, that fit the essentials of the proposed model.

  8. Energy transfer from a laser pulse to a blast wave in reduced-pressure air atmospheres

    International Nuclear Information System (INIS)

    Focusing a transversely excited atmospheric CO2 laser beam in air atmospheres induced a blast wave. The kinetic energy of a laser-induced blast wave was determined from shadowgraph images of shock wave expansion. Results showed that the fraction of input laser energy that is converted into the blast wave energy decreased from 0.45 to 0.2 concomitant with the decrease in ambient pressure from 100 to 10 kPa. Also, it was insensitive to input laser energy from 4 to 13 J

  9. Comparative Study on the Pulse Wave Variables and Sasang Constitution in Cerebral Infarction Patients and Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Ko KiDuk

    2007-06-01

    Full Text Available This study was performed to determine whether a pulse analyzer was useful 1 to characterize the variables of pulse wave of cerebral infarction patieno (CI, compared with those of healthy subjects, as well as 2 to determine Sasang Constitution in CI and healthy subjects. 1. Calibrated in Gwan, the amount of energy(Energy, height of main peak(H1, height of aorticvalley(H2, height of aortic peak(H3, total area of pulse wave(At, and area of main peak width(Aw of the CI group were higher than those of the healthy group. 2. Calibrated in Cheek, Energy, H1, H2, H3, height of valve valley(H4, At, Aw, and main peak angle(MPA of the CI group were higher than those of the healthy group. 3. Among the healthy (subjects group, Taeumin showed the highest contact pressure(CP and height of valve peak(H5 calibrated in Chon. The main peak width divided by whole time of pulse wave(MPW/T calibrated in Gwan and Cheok, was highest in Soyangin and was lowest in Taeumin. The H3 divided by H1(H3/H1 and the time to valve valley minus the time to main peak and divided by T[(T4-T1/T] calibrated in Cheek were highest in Soyangin. The time to main peak(T1 was longest in Soumin. 4. Among the CI group, At calibrated in Chon was widest in Taeumin and was narrowest in Soumin The time to aortic peak(T3 calibrated in Cheek was longest in Soumin and was shortest in Soyangin. The time to valve peak(T5 was shortest in Soyangin. 5. There were main effects of cerebral infarction in the area of systolic period(As and area of diastolic period(Ad calibrated in Chon, Energy calibrated in Cwan, and Energy, H1, H2, H3, (H4+H5/Hl, and MPA calibrated in Cheek. 6. There were main effects of Sasang Constitution in (T4-T1/T, area of systolic period(As, and Ad calibrated in Chon. 7. The interactions between the cerebral infarction and Sasang Constitution were observed in H5/H1 , T, At, As, Ad, and MPA calibrated in Chon, H4, T4, (T4-T1/T, As, and Ad calibrated in Cwan, and 74,75, and MPW calibrated

  10. Investigation of low-temperature-grown GaAs photoconductive antennae for continuous-wave and pulsed terahertz generation

    OpenAIRE

    Loata, Gabriel C.

    2007-01-01

    The main subject of the thesis is the investigation of low-temperature-grown (LTG) GaAs-based photoconductive switches used in the generation of continuous-wave (CW) and pulsed terahertz (THz) radiation. The use of photoconductive switches based on low-temperature-grown GaAs proved to be a viable option in generating electromagnetic transients on a subpicosecond time-scale, corresponding to frequencies of ~1012 Hz (between microwave and far-infrared). The most appealing property of LTG-GaAs i...

  11. Optical Force on Two-level Atoms by Few-cycle Pulsed Gaussian Laser field beyond the Rotating Wave Approximation

    OpenAIRE

    Kumar, Parvendra; Sarma, Amarendra K.

    2011-01-01

    We report a study on light force on a beam of neutral two-level atoms superimposed upon a few-cycle pulsed Gaussian laser field under both resonant and off-resonant condition. The phenomena of focusing, defocusing and steering of the neutral atoms in the laser field is analysed by solving the optical Bloch equation beyond the rotating wave approximation and the force equation self-consistently .We find that two-level atoms in an atomic beam could be focused and defocused for large, positively...

  12. SiOx Ink-Repellent Layer Deposited by Radio Frequency (RF) Plasmas in Continuous Wave and Pulse Mode

    International Nuclear Information System (INIS)

    Low surface energy layers, proposed application for non-water printing in computer to plate (CTP) technology, are deposited in both continuous wave and pulse radio frequency (13.56 MHz) plasma with hexamethyldisiloxane (HMDSO) as precursor. It is found that the plasma mode dominates the polymer growth rate and the surface composition. Derived from the spectra of X-ray photoelectron spectroscopy (XPS) and combined with printable test it is concluded that concentration of Si in coatings plays an important role for the ink printability and the ink does not adhere on the surface with high silicon concentration

  13. Power microwave pulse generation of resonant relativistic backward wave tube with power supply based on explosive magnetocumulative generators

    International Nuclear Information System (INIS)

    High-power microwave radiation has been generated using a resonant relativistic backward wave oscillator (BWO) powered by a high voltage source comprising an inductive energy storage and an electric-explosion current switch, the results of the experiment are provided. The high voltage source and the BWO magnetic system are energy pumped by explosive magnetocumulative generators. In the experiments the setup generated 30-ns single-mode radiation pulses with a carrier frequency of 3.6 GHz at a peak power of 0.75 GW

  14. High levels of mannose-binding lectin are associated with lower pulse wave velocity in uraemic patients

    DEFF Research Database (Denmark)

    Hornum, Mads; Bay, Jakob T; Clausen, Peter;

    2014-01-01

    MBL on vascular parameters in uraemic patients. METHODS: A cohort of 98 patients with end stage renal disease (ESRD) awaiting kidney transplantation had pulse wave velocity (PWV) and augmentation index (AIX) examined by tonometry and endothelial dependent flow-mediated (FMD) and endothelial...... group with high MBL levels. No difference was seen in FMD and NID. CONCLUSIONS: High levels of MBL are associated with lower PWV and the use of antihypertensive drugs in a cohort of patients with ESRD awaiting kidney transplantation suggesting a beneficial role of high levels of MBL on arterial...

  15. Theory and experiment of Fourier-Bessel field calculation and tuning of a pulsed wave annular array

    DEFF Research Database (Denmark)

    Fox, Paul D.; Jiqi, Cheng; Jian-yu, Lu

    2003-01-01

    A one-dimensional (1D) Fourier-Bessel series method for computing and tuning (beamforming) the linear lossless field of flat pulsed wave annular arrays is developed and supported with both numerical simulation and experimental verification. The technique represents a new method for modeling and...... tuning the propagated field by linking the quantized surface pressure profile to a known set of limited diffraction Bessel beams propagating into the medium. This enables derivation of an analytic expression for the field at any point in space and time in terms of the transducer surface pressure profile...

  16. Pressure waves in liquid mercury target from pulsed heat loads and the possible way controlling their effects

    Energy Technology Data Exchange (ETDEWEB)

    Ni, L.; Skala, K. [Paul Scherrer Institute, Villingen (Switzerland)

    1996-06-01

    In ESS project liquid metals are selected as the main target for the pulsed spallation neutron source. Since the very high instantaneous energy is deposited on the heavy molten target in a very short period time, pressure waves are generated. They travel through the liquid and cause high stress in the container. Also, additional stress should be considered in the wall which is the result of direct heating of the target window. These dynamic processes were simulated with computational codes with the static response being analized first. The total resulting dynamic wall stress has been found to have exceeded the design stress for the selected container material. Adding a small amount of gas bubbles in the liquid could be a possible way to reduce the pressure waves.

  17. Noninvasive pulse wave analysis for the determination of central artery stiffness

    DEFF Research Database (Denmark)

    Wittrock, Marc; Scholze, Alexandra; Compton, Friederike; Schaefer, Juergen-Heiner; Zidek, Walter; Tepel, Martin

    2009-01-01

    Central artery stiffness predicts cardiovascular structural damage and clinical outcome. It is controversial whether central artery stiffness can be determined by noninvasive measurements. We compared noninvasive determination of central artery stiffness obtained from applanation tonometry of the...... peripheral radial artery waveform with invasive measurements of the ratio of pulse-pressure-to-stroke-volume. A total of 112 invasive measurements of the ratio of pulse-pressure-to-stroke-volume and noninvasive determinations of central artery stiffness were performed in 49 patients on the intensive care...... unit. In 13 out of 112 attempts of noninvasive measurements (12%) radial pulse could not be obtained using applanation tonometry because of cardiac arrhythmia or radial pulse could not be detected. These 13 failing noninvasive measurements were attempted in 7 patients. In the remaining cases we found a...

  18. Mechanical effects induced by shock waves generated by high energy laser pulses

    OpenAIRE

    Fournier, J.; Ballard, P.; P. Merrien; Barralis, J.; Castex, L.; Fabbro, R.

    1991-01-01

    Specimens made of low alloy and non alloyed medium carbon steels were subjected to high energy laser pulses. Direct ablation and confined plasma procedures were both investigated. An optimum impulse momentum transfer to the material is attained with a pulse duration of 30 ns and a power density of 10 GW .cm2. Fatigue testing shows that the fatigue strengths of the selected materials are significantly increased. This can be related to the fact that laser shock processing generates an appropria...

  19. Dissipative Rogue Waves Generated by Chaotic Pulse Bunching in a Mode-Locked Laser

    Science.gov (United States)

    Lecaplain, C.; Grelu, Ph.; Soto-Crespo, J. M.; Akhmediev, N.

    2012-06-01

    Rare events of extremely high optical intensity are experimentally recorded at the output of a mode-locked fiber laser that operates in a strongly dissipative regime of chaotic multiple-pulse generation. The probability distribution of these intensity fluctuations, which highly depend on the cavity parameters, features a long-tailed distribution. Recorded intensity fluctuations result from the ceaseless relative motion and nonlinear interaction of pulses within a temporally localized multisoliton phase.

  20. Propagation of the nuclear electromagnetic pulse ground wave%核电磁脉冲地波传播规律

    Institute of Scientific and Technical Information of China (English)

    孙蓓云; 程引会; 聂鑫; 周辉

    2012-01-01

    The principle of the ground wave propagation for Electromagnetic Pulse(EMP) is presented. The propagation function of ground wave varying with the distance and frequency is developed as the ground conductivity above 0.005 S/m, and the EMP ground wave of nuclear explosion at different distances are computed. The results show that the amplitude of the propagation function is reduced with the increasing of frequency and distance, and the EMP ground wave is attenuated by ten times at a distance of 500 km from nuclear explosion location.%介绍了核电磁脉冲地波传播的理论计算方法,研究了当大地电导率大于0.005 S/m时,地波传播函数随频率及传播距离的变化规律,并计算了不同传播距离核爆电磁脉冲的地波电场.结果表明,频率越高,传播距离越远,传播函数的幅值越小;核爆电磁脉冲的传播距离为500 km时,电场的幅度会有大于一个量级的衰减.

  1. Small gas bubble experiment for mitigation of cavitation damage and pressure waves in short-pulse mercury spallation targets

    International Nuclear Information System (INIS)

    Populations of small helium gas bubbles were introduced into a flowing mercury experiment test loop to evaluate mitigation of beam-pulse induced cavitation damage and pressure waves. The test loop was developed and thoroughly tested at the Spallation Neutron Source (SNS) prior to irradiations at the Los Alamos Neutron Science Center–Weapons Neutron Research (LANSCE–WNR) facility. Twelve candidate bubblers were evaluated over a range of mercury flow and gas injection rates by use of a novel optical measurement technique that accurately assessed the generated small bubble size distributions. Final selection for irradiation testing included two variations of a swirl bubbler provided by Japan Proton Accelerator Research Complex (J-PARC) collaborators and one orifice bubbler developed at SNS. Bubble populations of interest consisted of sizes up to 150 μm in radius with achieved gas volume fractions in the 10−5–10−4 range. The nominal WNR beam pulse used for the experiment created energy deposition in the mercury comparable to SNS pulses operating at 2.5 MW. Nineteen test conditions were completed each with 100 pulses, including variations on mercury flow, gas injection and protons per pulse. The principal measure of cavitation damage mitigation was pitting damage assessment on test specimens that were manually replaced for each test condition. Damage assessment was done after radiation decay and decontamination by optical and laser profiling microscopy with damaged area fraction and maximum pit depth being the more valued results. Damage was reduced by flow alone; the best mitigation from bubble injection was to one-third that of stagnant mercury. Other data collected included surface motion tracking by three Laser Doppler Vibrometers (LDV), test loop wall dynamic strain, beam diagnostics for charge and beam profile assessment, embedded hydrophones and pressure sensors, and sound measurement by a suite of conventional and contact microphones

  2. Measuring aortic pulse wave velocity using high-field cardiovascular magnetic resonance: comparison of techniques

    Directory of Open Access Journals (Sweden)

    Shaffer Jean M

    2010-05-01

    Full Text Available Abstract Background The assessment of arterial stiffness is increasingly used for evaluating patients with different cardiovascular diseases as the mechanical properties of major arteries are often altered. Aortic stiffness can be noninvasively estimated by measuring pulse wave velocity (PWV. Several methods have been proposed for measuring PWV using velocity-encoded cardiovascular magnetic resonance (CMR, including transit-time (TT, flow-area (QA, and cross-correlation (XC methods. However, assessment and comparison of these techniques at high field strength has not yet been performed. In this work, the TT, QA, and XC techniques were clinically tested at 3 Tesla and compared to each other. Methods Fifty cardiovascular patients and six volunteers were scanned to acquire the necessary images. The six volunteer scans were performed twice to test inter-scan reproducibility. Patient images were analyzed using the TT, XC, and QA methods to determine PWV. Two observers analyzed the images to determine inter-observer and intra-observer variabilities. The PWV measurements by the three methods were compared to each other to test inter-method variability. To illustrate the importance of PWV using CMR, the degree of aortic stiffness was assessed using PWV and related to LV dysfunction in five patients with diastolic heart failure patients and five matched volunteers. Results The inter-observer and intra-observer variability results showed no bias between the different techniques. The TT and XC results were more reproducible than the QA; the mean (SD inter-observer/intra-observer PWV differences were -0.12(1.3/-0.04(0.4 for TT, 0.2(1.3/0.09(0.9 for XC, and 0.6(1.6/0.2(1.4 m/s for QA methods, respectively. The correlation coefficients (r for the inter-observer/intra-observer comparisons were 0.94/0.99, 0.88/0.94, and 0.83/0.92 for the TT, XC, and QA methods, respectively. The inter-scan reproducibility results showed low variability between the repeated

  3. Noise-like pulse based on dissipative four-wave-mixing with photonic crystal fiber filled by reduced graphene oxide

    CERN Document Server

    Gao, Lei; Huang, Wei

    2014-01-01

    A noise-like pulse based on dissipative four-wave-mixing in a fiber cavity with photonic crystal fiber filled by reduced graphene oxide is proposed. Due to large evanescent field provided by 3 cm photonic crystal fiber and ultrahigh nonlinearity of reduced graphene oxide, this mixed structure provides excellent saturable absorption and high nonlinearity, which are necessary for generating four-wave-mixing (FWM). We experimentally prove that the mode-locked laser transfers its energy from center wavelength to sidebands through degenerate FWM, and new frequencies are generated via cascaded FWM among those sidebands. During this process, the frequencies located in various orders of longitudinal modes of the ring cavity are supported, and others are suppressed due to destructive interference. As the longitudinal modes of the cavity with a spacing of 6.874 MHz are partially supported, the loosely fixed phase relationship results in noise-like pulse with a coherent peak of 530 fs locating on a pedestal of 730.693 p...

  4. Measurement of Spatial Pulse Wave Velocity by Using a Clip-Type Pulsimeter Equipped with a Hall Sensor and Photoplethysmography

    Directory of Open Access Journals (Sweden)

    Sang-Suk Lee

    2013-04-01

    Full Text Available A prototype of a clip-type pulsimeter equipped with a magnetic field-sensing semiconductor Hall sensor was developed. It has a permanent magnet attached in the “Chwan” position to the center of a radial artery. The clip-type pulsimeter is composed of a hardware system measuring voltage signals. To measure spatial pulse wave velocity (SPWV, the signal from the radial artery pulsimeter and that from the photoplethysmography (PPG were simultaneously compared. The pulse wave data from a clinical test of 39 clinical participants (male:female = 25:14 with a mean age of 24.36 (±2.35 years was analyzed. The mean SPWV, which was simultaneously measured from the radial artery pulsimeter and PPG, was 0.8 m/s. We suggest the SPWV results were higher for men than women, because of the better vascularity of terminal tissue in men. The findings of this research may be useful for developing a biomedical signal storage device for a U-health-care system.

  5. One-dimensional modelling of pulse wave propagation in human airway bifurcations in space-time variables.

    Science.gov (United States)

    Clavica, Francesco; Alastruey, Jordi; Sherwin, Spencer J; Khir, Ashraf W

    2009-01-01

    Airflow in the respiratory system is complicated as it goes through various regions with different geometries and mechanical properties. Three-dimensional (3-D) simulations are typically limited to local areas of the system because of their high computational cost. On the other hand, the one-dimensional (1-D) equations of flow in compliant tubes offer a good compromise between accuracy and computational cost when a global assessment of airflow in the system is required. The aim of the current study is to apply the 1-D formulation in space and time variables to study the propagation of a pulse wave in human airways; first in a simple system composed of just one bifurcation, trachea-main bronchi, according to the symmetrical Weibel model. Then extending the system to include a further generation, the bronchi branches. Pulse waveforms carry information about the functionality and morphology of the respiratory system and the 1-D modelling, in terms of space and time variables, represents an innovative approach for respiratory response interpretation. 1-D modelling in space-time variables has been extensively applied to simulate blood pressure and flow in the cardiovascular system. This work represents the first attempt to apply this formulation to study pulse waveforms in the human bronchial tree. PMID:19965046

  6. Comparison of therapeutic effects between pulsed and continuous wave 810-nm wavelength laser irradiation for traumatic brain injury in mice.

    Directory of Open Access Journals (Sweden)

    Takahiro Ando

    Full Text Available BACKGROUND AND OBJECTIVE: Transcranial low-level laser therapy (LLLT using near-infrared light can efficiently penetrate through the scalp and skull and could allow non-invasive treatment for traumatic brain injury (TBI. In the present study, we compared the therapeutic effect using 810-nm wavelength laser light in continuous and pulsed wave modes in a mouse model of TBI. STUDY DESIGN/MATERIALS AND METHODS: TBI was induced by a controlled cortical-impact device and 4-hours post-TBI 1-group received a sham treatment and 3-groups received a single exposure to transcranial LLLT, either continuous wave or pulsed at 10-Hz or 100-Hz with a 50% duty cycle. An 810-nm Ga-Al-As diode laser delivered a spot with diameter of 1-cm onto the injured head with a power density of 50-mW/cm(2 for 12-minutes giving a fluence of 36-J/cm(2. Neurological severity score (NSS and body weight were measured up to 4 weeks. Mice were sacrificed at 2, 15 and 28 days post-TBI and the lesion size was histologically analyzed. The quantity of ATP production in the brain tissue was determined immediately after laser irradiation. We examined the role of LLLT on the psychological state of the mice at 1 day and 4 weeks after TBI using tail suspension test and forced swim test. RESULTS: The 810-nm laser pulsed at 10-Hz was the most effective judged by improvement in NSS and body weight although the other laser regimens were also effective. The brain lesion volume of mice treated with 10-Hz pulsed-laser irradiation was significantly lower than control group at 15-days and 4-weeks post-TBI. Moreover, we found an antidepressant effect of LLLT at 4-weeks as shown by forced swim and tail suspension tests. CONCLUSION: The therapeutic effect of LLLT for TBI with an 810-nm laser was more effective at 10-Hz pulse frequency than at CW and 100-Hz. This finding may provide a new insight into biological mechanisms of LLLT.

  7. Electrochemical determination of 4-nitrophenol using uniform nanoparticle film electrode of glass carbon fabricated facilely by square wave potential pulses

    International Nuclear Information System (INIS)

    Highlights: • Uniform nanoparticle film of GC was easily prepared by square wave potential pulses. • The fabrication involves repeated anodic oxidation of smooth GC in NaOH solution. • The thin film decorated with functional groups showed high electrochemical activity. • The effects of preparation parameters on CV behaviors of 4-NP were investigated. • The film exhibited good performances for voltammetric determination of 4-NP. - Abstract: Voltammetric determination of 4-nitrophenol (4-NP) has been preformed at uniform nanoparticle film electrode (UNFE) of glass carbon (GC) (GC-UNFE). The UNFE was facilely fabricated from smooth GC surface in a blank solution of NaOH with square wave potential pulses (SWPPs). This film was composed of uniform, dense GC nanoparticles decorated with oxygen-containing functional groups and exhibited high electrochemical activity. The film formation might be related to repeated pulse electrochemical oxidation of GC surface. The as-prepared film was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The parameters including anodic potential, time and frequency of SWPPs for film preparation were examined on CV behaviors of 4-NP redox. The oxidation peak was chosen to the 4-NP determination, and under the optimized conditions, its currents varied linearly with a concentration range for 4-NP of 0.5–3000 μM (over two consecutive calibration curves) with a detection limit of 0.23 μM (3σ/slope) and quantification limit of 0.77 μM (10 σ/slope). The advantages of present method included easy fabrication, high sensitivity, good stability, good reproducibility and very broad linear range, and it was successfully applied to detect 4-NP in water samples with satisfied results

  8. Suppression of parasitic noise by strong Langmuir wave damping in quasitransient regimes of backward Raman amplification of intense laser pulses in plasmas.

    Science.gov (United States)

    Malkin, Vladimir; Fisch, Nathaniel

    2009-11-01

    Currently built powerful soft x-ray sources may be able to access intensities needed for backward Raman amplification (BRA) of x-ray pulses in plasmas. However, high plasma densities, needed to provide enough coupling between the pump and seed x-ray pulsed, cause strong damping of the Langmuir wave that mediates energy transfer from the pump to the seed pulse. Such damping could reduce the coupling, thus making efficient BRA impossible. This work shows that efficient BRA can survive despite the Langmuir wave damping significantly exceeding the linear BRA growth rate. Moreover, the strong Langmuir wave damping can suppress deleterious instabilities of BRA seeded by the thermal noise. This shows that it may be feasible to observe x-ray BRA for the first time soon.

  9. Thermally induced transparency for short spin wave pulses in yttrium iron garnet (YIG) films

    Science.gov (United States)

    Ordonez Romero, Cesar Leonardo; Kolokoltsev, Oleg; Gomez Arista, Ivan; Qureshi, Naser; Monsiváis Galindo, Guillermo; Vargas Hernández, Hesiquio

    2014-03-01

    The compensation of spin wave propagation losses plays a very important role in the development of novel magnonic devices. Up to now, however, most of the known amplification methods present relative narrow frequency bandwidths due to their resonant nature. In this work, we present compensation of the propagation losses or pseudo-amplification of travelling spin waves by tailoring the bias magnetic field profile. The thermally-induced non-uniform profile of the magnetization introduced on an Yttrium Iron Garnet (YIG) thin film by a localized spot of a cw argon-ion laser creates the conditions to observe the complete compensation of the spin wave propagation losses. The spin wave evolution was mapped with a time and spaced resolved inductive magneto-dynamic prove system. The experiment was carried out using a uniform sample of single-crystal YIG film grown on a gallium-gadolinium garnet (GGG) substrate. The 2mm-wide, 20mm-long and 6microns-thick YIG strip was saturated with an external magnetic field enabling the set up for the propagation of magneto-static surface waves. This work was supported by the UNAM-DGAPA-PAPIIT IA100413.

  10. Bulk waves excited by a laser line pulse in a two-layered cylinder

    Science.gov (United States)

    Pan, Y.; Chigarev, N.; Audoin, B.

    2010-01-01

    The acoustic displacements excited by a laser line source under either the ablation or thermoelastic regime are calculated for a two-layered cylinder made of homogeneous and isotropic materials. Two samples made by welding tin in two different copper tubes are considered. Experimental displacements are observed by the laser ultrasonic technique, and corresponding theoretical waveforms are calculated. Good agreement is found in the arrival time, shape, and relative amplitude of various longitudinal and shear bulk waves propagating in the two-layered cylinders, and the waves reflected by the interface are further identified by the ray trajectory analysis. The longitudinal wave reflected at the interface may be used for the nondestructive evaluation of the interface quality.

  11. Nonlinear self-focus of pulsed-wave beams in Kerr media

    Energy Technology Data Exchange (ETDEWEB)

    Judkins, J.B.

    1992-12-31

    A modified finite-difference time-domain method for solving Maxwell`s equations in nonlinear media is presented. This method allows for a finite response time to be incorporated in the medium, physically creating dispersion and absorption mechanisms. The technique models electromagnetic fields in two space dimensions and time and encompasses both the TE{sub z} and TM{sub z} set of decoupled field equations. Aspects of an ultra-short pulsed Gaussian beam are studied in a variety of linear and nonlinear environments to demonstrate that the methods developed here can be used efficaciously in the modeling of pulses in complex problem space geometries even when nonlinearities are present.

  12. Investigation of a diode-pumped intracavity optical parametric oscillator in pulsed and continuous wave operation

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Skettrup, Torben; Balle-Petersen, O.;

    2001-01-01

    Summary form only given. CW and pulsed compact tunable laser sources in the infrared have widespread scientific, medical and industrial applications. Such a laser source can be obtained by use of a diode-pumped intracavity optical parametric oscillator (IOPO). We report on a IOPO based on a Yb:YA...... lens to generate a beam waist in the PPLN crystal, a dichroic mirror to separate the laser and signal fields and two end mirrors...

  13. Solitary pulses and periodic waves in the parametrically driven complex Ginzburg-Landau equation

    OpenAIRE

    Sakaguchi, Hidetsugu; Malomed, Boris

    2003-01-01

    A one-dimensional model of a dispersive medium with intrinsic loss, compensated by a parametric drive, is proposed. It is a combination of the well-known parametrically driven nonlinear Schr\\"{o}dinger (NLS) and complex cubic Ginzburg-Landau equations, and has various physical applications (in particular, to optical systems). For the case when the zero background is stable, we elaborate an analytical approximation for solitary-pulse (SP) states. The analytical results are found to be in good ...

  14. Dynamics of atomic spin-orbit-state wave packets produced by short-pulse laser photodetachment

    CERN Document Server

    Law, S M K

    2016-01-01

    We analyse the experiment by Hultgren et al. [Phys. Rev. A {\\bf 87}, 031404 (2013)] on orbital alignment and quantum beats in coherently excited atomic fine-structure manifolds produced by short-pulse laser photodetachment of C$^-$, Si$^-$ and Ge$^-$ negative ions, and derive a formula that describes the beats. Analysis of the experimental data enables us to extract the non-coherent background contribution for each species, and indicates the need for a full density matrix treatment of the problem.

  15. Ionospheric cusp flows pulsed by solar wind Alfvén waves

    OpenAIRE

    Prikryl, P.; Provan, G.; K. A. McWilliams; Yeoman, T. K.

    2002-01-01

    Pulsed ionospheric flows (PIFs) in the cusp foot-print have been observed by the SuperDARN radars with periods between a few minutes and several tens of minutes. PIFs are believed to be a consequence of the interplanetary magnetic field (IMF) reconnection with the magnetospheric magnetic field on the dayside magnetopause, ionospheric signatures of flux transfer events (FTEs). The quasiperiodic PIFs are correlated with Alfvénic fluctuations observed in the upstream solar wind. It is con...

  16. Reconstruction of wave features in wind-driven water film flow using ultrasonic pulse-echo technique

    Science.gov (United States)

    Liu, Yang; Bond, Leonard J.; Hu, Hui

    2016-02-01

    Aircraft operating in weather conditions that can cause glaze icing face the risk of performance degradation, and increased costs in de-icing procedures. The water run-back in glaze ice accretion can redistribute the impinging water mass and disturb the local flow field, and hence, affect the morphology of ice accretion. Understanding the mechanism of the surface water film transportation is important and challenging, and critical to enabling improvement in the modeling of glaze icing. In this study, an ultrasonic multi-transducer (sparse array) pulse-echo (UMTPE) technique was developed to measure thin film thickness fluctuation. The technical basis for UMTPE technique and the factors that influence the measurements are described. The UMTPE technique was configured to provide time-resolved multi-point thickness measurements. Quantitative measurements of the wind-driven water film flow are achieved by using the UMTPE technique. Point-wise thickness variations can be obtained from each individual channel in the UMTPE system. Span-wise thickness profile can be derived by interpolating the point-wise measurements. The span-wise thickness profiles can be expanded in time domain, which shows the overall flow structures. The velocity of surface wave features is derived by performing a cross-correlation of the upstream and downstream thickness variations, which is then used to transform the temporal thickness fluctuation into the spatial wave structures. The time-resolved spatial flow structures are obtained by applying the transformation along time axis, which present more details of wave structures and the evolution of wave features.

  17. The test ability of an adaptive pulse wave for ADC testing

    NARCIS (Netherlands)

    Sheng, Xiaoqin; Kerkhoff, Hans G.

    2010-01-01

    In the conventional ADC production test method, a high-quality analogue sine wave is applied to the Analogue-to-Digital Converter (ADC), which is expensive to generate. Nowadays, an increasing number of ADCs are integrated into a system-on-chip (SoC) platform design, which usually contains a digital

  18. Bramwell-Hill modeling for local aortic pulse wave velocity estimation: a validation study with velocity-encoded cardiovascular magnetic resonance and invasive pressure assessment

    OpenAIRE

    Westenberg Jos JM; van Poelgeest Eveline P; Steendijk Paul; Grotenhuis Heynric B; Jukema JW; de Roos Albert

    2012-01-01

    Abstract Background The Bramwell-Hill model describes the relation between vascular wall stiffness expressed in aortic distensibility and the pulse wave velocity (PWV), which is the propagation speed of the systolic pressure wave through the aorta. The main objective of this study was to test the validity of this model locally in the aorta by using PWV-assessments based on in-plane velocity-encoded cardiovascular magnetic resonance (CMR), with invasive pressure measurements serving as the gol...

  19. Simultaneously measured inter-arm and inter-leg systolic blood pressure differences and cardiovascular risk stratification: a systemic review and meta-analysis.

    Science.gov (United States)

    Singh, Sukhchain; Sethi, Ankur; Singh, Mukesh; Khosla, Kavia; Grewal, Navsheen; Khosla, Sandeep

    2015-08-01

    Association of inter-arm systolic blood pressure difference (IASBPD) with cardiovascular (CV) morbidity and mortality remains controversial. We aimed to thoroughly examine all available evidence on inter-limb blood pressure (BP) difference and its association with CV risk and outcomes. We searched PubMed, EMBASE, CINAHL, Cochrane library, and Ovid for studies reporting bilateral simultaneous BP measurements in arms or legs and risk of peripheral arterial disease (PAD), coronary artery disease, cerebrovascular disease, subclavian stenosis, or mortality. Random-effect meta-analysis was performed to compare effect estimates. Twenty-seven studies met inclusion criteria, but only 17 studies (18 cohorts) were suitable for analysis. IASBPD of 10 mmHg or more was associated with PAD (risk ratios, 2.22; 1.41-3.5; P = .0006; sensitivity 16.6%; 6.7-35.4; specificity 91.9%; 83.1-96.3; 8 cohorts; 4774 subjects), left ventricular mass index (standardized mean difference 0.21; 0.03-0.39; P = .02; 2 cohort; 1604 subjects), and brachial-ankle pulse wave velocity (PWV) (one cohort). Association of PAD remained significant at cutoff of 15 mmHg (risk ratios, 1.91; 1.28-2.84; P = .001; 5 cohorts; 1914 subjects). We could not find statistically significant direct association of coronary artery disease, cerebrovascular disease, CV, and all-cause mortality in subjects with IASBPD of 10 mmHg or more, 15 mmHg or more, and inter-leg systolic BP difference of 15 mmHg or more. Inter-leg BP difference of 15 mmHg or more was strong predictor of PAD (P = .0001) and brachial-ankle PWV (P = .0001). Two invasive studies showed association of IASBPD and subclavian stenosis (estimates could not be combined). In conclusion, inter-arm and leg BP differences are strong predictors of PAD. IASBPD may be associated with subclavian stenosis, high left ventricular mass effect, and higher brachial-ankle PWVs. Inter-leg BP difference may also be associated with high left ventricular mass effect and higher

  20. Silencing by blasting: combination of laser pulse induced stress waves and magnetophoresis for siRNA delivery

    Science.gov (United States)

    Babincová, M.; Babincová, N.; Durdík, S.; Bergemann, C.; Sourivong, P.

    2016-06-01

    A new method is developed for efficient delivery of short interference RNA into cells using combination of magnetophoresis for pre-concentration of siRNA-magnetic nanoparticle complex on the surface of cells with subsequent nanosecond laser pulse generating stress waves in transfection chamber, which is able to permeabilize cell membrane for the facilitated delivery of siRNA into the cell interior. As has been shown using siRNA inducing cell apoptosis, combination of these two physical factors increased the efficiency of three different human carcinoma cells transfection to 93%, 89%, and 84%, for HeLa (cervical carcinoma), MCF-7 (breast carcinoma), and UCI-107 (ovarian carcinoma) cells, respectively. This new physical method of siRNA delivery may have therefore far reaching applications in biotechnology and functional genomics.

  1. Dynamics of shock waves and cavitation bubbles in bilinear elastic-plastic media, and the implications to short-pulsed laser surgery

    Science.gov (United States)

    Brujan, E.-A.

    2005-01-01

    The dynamics of shock waves and cavitation bubbles generated by short laser pulses in water and elastic-plastic media were investigated theoretically in order to get a better understanding of their role in short-pulsed laser surgery. Numerical simulations were performed using a spherical model of bubble dynamics which include the elastic-plastic behaviour of the medium surrounding the bubble, compressibility, viscosity, density and surface tension. Breakdown in water produces a monopolar acoustic signal characterized by a compressive wave. Breakdown in an elastic-plastic medium produces a bipolar acoustic signal, with a leading positive compression wave and a trailing negative tensile wave. The calculations revealed that consideration of the tissue elasticity is essential to describe the bipolar shape of the shock wave emitted during optical breakdown. The elastic-plastic response of the medium surrounding the bubble leads to a significant decrease of the maximum size of the cavitation bubble and pressure amplitude of the shock wave emitted during bubble collapse, and shortening of the oscillation period of the bubble. The results are discussed with respect to collateral damage in short-pulsed laser surgery.

  2. Impact of ADMA, endothelial progenitor cells and traditional cardiovascular risk factors on pulse wave velocity among prediabetic individuals

    Directory of Open Access Journals (Sweden)

    Protopsaltis Ioannis

    2012-11-01

    Full Text Available Abstract Background Central arterial stiffness represents a well-established predictor of cardiovascular disease. Decreased circulating endothelial progenitor cells (EPCs, increased asymmetric dimethyl-arginine (ADMA levels, traditional cardiovascular risk factors and insulin resistance have all been associated with increased arterial stiffness. The correlations of novel and traditional cardiovascular risk factors with central arterial stiffness in prediabetic individuals were investigated in the present study. Methods The study population consisted of 53 prediabetic individuals. Individuals were divided into groups of isolated impaired fasting glucose (IFG, isolated impaired glucose tolerance (IGT and combined IGT-IFG. Age, sex, family history of diabetes, smoking history, body mass index (BMI, waist to hip ratio (WHR, waist circumference (WC, blood pressure, lipid profile, levels of high sensitive C-reactive protein (hsCRP, glomerular filtration rate (GFR, and history of antihypertensive or statin therapy were obtained from all participants. Insulin resistance was evaluated using the Homeostatic Model Assessment (HOMA-IR. Carotid -femoral pulse wave velocity was used as an index of arterial stiffness. Circulating EPC count and ADMA serum levels were also determined. Results Among studied individuals 30 (56.6% subjects were diagnosed with isolated IFG, 9 (17% with isolated IGT (17% and 14 with combined IFG-IGT (26.4%. In univariate analysis age, mean blood pressure, fasting glucose, total cholesterol, LDL cholesterol, and ADMA levels positively correlated with pulse-wave velocity while exercise and GFR correlated negatively. EPC count did not correlate with PWV. In multivariate stepwise regression analysis PWV correlated independently and positively with LDL-Cholesterol (low density lipoprotein and ADMA levels and negatively with exercise. Conclusions Elevated ADMA and LDL-C levels are strongly associated with increased arterial stiffness among

  3. Endotoxin-induced and vaccine-induced systemic inflammation both impair endothelium-dependent vasodilation, but not pulse wave reflection

    Directory of Open Access Journals (Sweden)

    Lind L

    2012-07-01

    Full Text Available Lars Lind,1 Johannes Hulthe,2,3 Annika Johansson,3 Ewa Hedner31Department of Medicine, University Hospital, Uppsala, 2Sahlgrenska Hospital, Gothenburg, 3AstraZeneca Research and Development, Mölndal, SwedenBackground: Inflammation induced by either endotoxin or vaccination has previously been shown to impair endothelium-dependent vasodilation (EDV in healthy young individuals. However, the vascular effects of these two mechanisms of inducing inflammation have not been compared in the same individuals.Methods: Twelve young healthy males were studied at the same time of the day on three occasions in a random order; on one occasion 4 hours following an endotoxin injection (Escherichia coli endotoxin, 20 IU/kg, on another occasion 8 hours following vaccination against Salmonella typhi, and on a third occasion 4 hours following a saline control injection. EDV and endothelium-independent vasodilation (EIDV were evaluated by local infusions of acetylcholine and sodium nitroprusside in the brachial artery, and forearm blood flow was measured with venous occlusion plethysmography. The augmentation index was determined by pulse wave analysis as an index of pulse wave reflection.Results: Both endotoxin and vaccination impaired EDV to a similar degree compared with the saline control (P = 0.005 and P = 0.014, respectively. EIDV was not significantly affected by inflammation. Endotoxin, but not vaccination, increased body temperature and circulating levels of intracellular adhesion molecule-1 and interleukin-6. Augmentation index was not affected by the interventions.Conclusion: Despite the fact that endotoxin induced a more pronounced degree of inflammation than vaccination, both inflammatory challenges impaired EDV to a similar degree, supporting the view that different inflammatory stimuli could induce harmful effects on the vasculature.Keywords: endothelium, endotoxin, vaccination, vasodilation, inflammation

  4. Normal values of aortic dimensions, distensibility, and pulse wave velocity in children and young adults: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Voges Inga

    2012-11-01

    Full Text Available Abstract Background Aortic enlargement and impaired bioelasticity are of interest in several cardiac and non-cardiac diseases as they can lead to cardiovascular complications. Cardiovascular magnetic resonance (CMR is increasingly accepted as a noninvasive tool in cardiovascular evaluation. Assessment of aortic anatomy and bioelasticity, namely aortic distensibility and pulse wave velocity (PWV, by CMR is accurate and reproducible and could help to identify anatomical and bioelastic abnormalities of the aorta. However, normal CMR values for healthy children and young adults are lacking. Methods Seventy-one heart-healthy subjects (age 16.4 ± 7.6 years, range 2.3 - 28.3 years were examined using a 3.0 Tesla CMR scanner. Aortic cross-sectional areas and aortic distensibility were measured at four positions of the ascending and descending thoracic aorta. PWV was assessed from aortic blood flow velocity measurements in a aortic segment between the ascending aorta and the proximal descending aorta. The Lambda-Mu-Sigma (LMS method was used to obtain percentile curves for aortic cross-sectional areas, aortic distensibility and PWV according to age. Results Aortic areas, PWV and aortic distensibility (aortic cross-sectional areas: r = 0.8 to 0.9, p  Conclusions This study provides percentile curves for cross-sectional areas, distensibility and pulse wave velocity of the thoracic aorta in children and young adolescents between their 3rd and 29th year of life. These data may serve as a reference for the detection of pathological changes of the aorta in cardiovascular disease.

  5. Remote Continuous Wave and Pulsed Laser Raman Detection of Chemical Warfare Agents Simulants and Toxic Industrial Compounds

    Science.gov (United States)

    Ortiz-Rivera, William; Pacheco-Londoño, Leonardo C.; Hernández-Rivera, Samuel P.

    2010-09-01

    This study describes the design, assembly, testing and comparison of two Remote Raman Spectroscopy (RRS) systems intended for standoff detection of hazardous chemical liquids. Raman spectra of Chemical Warfare Agents Simulants (CWAS) and Toxic Industrial Compounds (TIC) were measured in the laboratory at a 6.6 m source-target distance using continuous wave (CW) laser detection. Standoff distances for pulsed measurements were 35 m for dimethyl methylphosphonate (DMMP) detection and 60, 90 and 140 m for cyclohexane detection. The prototype systems consisted of a Raman spectrometer equipped with a CCD detector (for CW measurements) and an I-CCD camera with time-gated electronics (for pulsed laser measurements), a reflecting telescope, a fiber optic assembly, a single-line CW laser source (514.5, 488.0, 351.1 and 363.8 nm) and a frequency-doubled single frequency Nd:YAG 532 nm laser (5 ns pulses at 10 Hz). The telescope was coupled to the spectrograph using an optical fiber, and filters were used to reject laser radiation and Rayleigh scattering. Two quartz convex lenses were used to collimate the light from the telescope from which the telescope-focusing eyepiece was removed, and direct it to the fiber optic assembly. To test the standoff sensing system, the Raman Telescope was used in the detection of liquid TIC: benzene, chlorobenzene, toluene, carbon tetrachloride, cyclohexane and carbon disulfide. Other compounds studied were CWAS: dimethylmethyl phosphonate, 2-chloroethyl ethyl sulfide and 2-(butylamino)-ethanethiol. Relative Raman scattering cross sections of liquid CWAS were measured using single-line sources at 532.0, 488.0, 363.8 and 351.1 nm. Samples were placed in glass and quartz vials at the standoff distances from the telescope for the Remote Raman measurements. The mass of DMMP present in water solutions was also quantified as part of the system performance tests.

  6. Ablation loading efficiency and shock wave generation driven by powerful laser pulses of different wavelengths.

    Czech Academy of Sciences Publication Activity Database

    Gus'kov, S. Yu.; Borodziuk, S.; Demchenko, N. N.; Jungwirth, Karel; Kálal, M.; Kasperczuk, A.; Kondrashov, V. N.; Králiková, Božena; Krouský, Eduard; Limpouch, J.; Mašek, Karel; Pfeifer, Miroslav; Pisarczyk, P.; Pisarczyk, T.; Rohlena, Karel; Rozanov, V. B.; Skála, Jiří; Ullschmied, Jiří

    Frascati : ENEA Frascati, 2005 - (Strangio, C.), s. 266-270 [European Conference on Laser Interaction with Matter/28th./. Roma (IT), 06.10.2004-10.10.2004] R&D Projects: GA MŠk LN00A100; GA AV ČR KSK2043105 Keywords : PALS * laser-produced plasma * ablation * shock wave * absorption efficiency * efficiency of ablation loading * crater formation * 2D modelling Subject RIV: BH - Optics, Masers, Lasers

  7. Performance of a reflectometer at continuous wave and pulsed neutron sources

    International Nuclear Information System (INIS)

    The Monte-Carlo simulations presented here involve simulations of reflectivity measurements of one sample using a reflectometer of traditional geometry at different neutron sources. The same reflectometer was used in all simulations. Only the characteristics of the neutron source, and the technique used to measure neutron wavelength were changed. In the case of the CW simulation, a monochromating crystal was used to select a nearly monochromatic beam (MB) from the neutron spectrum. In the simulations of the pulse sources, the time needed to traverse a fixed distance was measured, from which neutron wavelength is deduced

  8. Investigation of a diode-pumped intracavity optical parametric oscillator in pulsed and continuous wave operation

    OpenAIRE

    Jensen, Ole Bjarlin; Skettrup, Torben; Balle-Petersen, O.; Bruun-Larsen, M.

    2001-01-01

    Summary form only given. CW and pulsed compact tunable laser sources in the infrared have widespread scientific, medical and industrial applications. Such a laser source can be obtained by use of a diode-pumped intracavity optical parametric oscillator (IOPO). We report on a IOPO based on a Yb:YAG laser incorporating a periodically poled LiNbO3 (PPLN) crystal inside the laser cavity to take advantage of the high circulating intracavity field. The Yb:YAG crystal is pumped by a reliable 940 nm ...

  9. Development of a shock wave adhesion test for composite bonds by laser pulsed and mechanical impacts

    Science.gov (United States)

    Ecault, Romain; Boustie, Michel; Touchard, Fabienne; Arrigoni, Michel; Berthe, Laurent; CNRS Collaboration

    2013-06-01

    Evaluating the bonding quality of composite material is becoming one of the main challenges faced by aeronautic industries. This work aims the development of a technique using shock wave, which would enable to quantify the bonding mechanical quality. Laser shock experiments were carried out. This technique enables high tensile stress generation in the thickness of composite bond without any mechanical contact. The resulting damage has been quantified using different method such as confocal microscopy, ultrasound and cross section observation. The discrimination between a correct bond and a weak bond was possible thanks to these experiments. Nevertheless, laser sources are not well adapted for optimization of such a test since it has often fixed parameters. That is why mechanical impacts bonded composites were also performed in this work. By changing the thickness of aluminum projectiles, the tensile stresses generated by the shock wave propagation were moved toward the composite/bond interface. The observations made prove that the optimization of the technique is possible. The key parameters for the development of a bonding test using shock wave have been identified.

  10. Development of a shock wave adhesion test for composite bonds by pulsed laser and mechanical impacts

    Science.gov (United States)

    Ecault, R.; Boustie, M.; Touchard, F.; Arrigoni, M.; Berthe, L.

    2014-05-01

    Evaluating the bonding quality of composite material is becoming one of the main challenges faced by aeronautic industries. This work aims to the development of a technique using shock wave, which would enable to quantify the bonding mechanical quality. Laser shock experiments were carried out. This technique enables high tensile stress generation in the thickness of composite bonds. The resulting damage has been quantified using different methods such as confocal microscopy, ultrasound and cross section observation. The discrimination between a correct bond and a weak bond was possible thanks to these experiments. Nevertheless, laser sources are not well adapted for optimization of such a test because of often fixed settings. That is why mechanical impacts on bonded composites were also performed in this work. By changing the thickness of aluminum projectiles, the generated tensile stresses by the shock wave propagation were moved toward the composite/bond interface. The made observations prove that the technique optimization is possible. The key parameters for the development of a bonding test using shock waves have been identified.

  11. 10-GHz return-to-zero pulse source tunable in wavelength with a single- or multiwavelength output based on four-wave mixing in a newly developed highly nonlinear fiber

    DEFF Research Database (Denmark)

    Clausen, A. T.; Oxenlowe, L.; Peucheret, Christophe;

    2001-01-01

    In this letter, a novel scheme for a wavelength-tunable pulse source (WTPS) is proposed and characterized. It is based on four-wave mixing (FWM) in a newly developed highly nonlinear fiber between a return-to-zero (RZ) pulsed signal at a fixed wavelength and a continuous wave probe tunable in...

  12. Compliance of the normal-sized aorta in adolescents with Marfan syndrome: comparison of MR measurements of aortic distensibility and pulse wave velocity

    International Nuclear Information System (INIS)

    Purpose: To compare the aortic compliance of the normal-sized aorta of adolescents with Marfan syndrome and healthy controls using MR measurements of the aortic distensibility and pulse wave velocity. Materials and Methods: Fourteen patients (median age: 15 [9-21] years) and 11 healthy subjects (23 [12-32] years) were examined at 1.5 T. The MR protocol included 2D steady-state free precession (SSFP)-CINE MRI of the aortic distensibility and PC-MRI of the pulse wave velocity. All measurements were positioned perpendicular to the descending aorta at the level of the diaphragm for assessing the changes in the aortic cross-sectional areas and additionally above and below this plane for assessing the pulse wave velocity. In addition contrast-enhanced 3D-MR angiography was performed in adolescents with Marfan syndrome to exclude morphologic changes and to prove normal-sized aorta. Results: Compared with control subjects, adolescents with Marfan syndrome had significantly decreased distensibility and significantly increased pulse wave velocity (χ2-test, p = 0.0002) using an age-related non-linear regression analysis. The related aortic compliance was significantly decreased (χ2-test, p = 0.0002). There was a good correlation between the two methods (r = 0.86). A low intraobserver variability was found for both methods (≤ 2 %). (orig.)

  13. Reference values of central blood pressure and pulse wave velocity in relation with 24 hours ambulatory blood pressure monitoring in Belgian healthy young subjects

    OpenAIRE

    Saint-Remy, Annie; Krzesinski, Jean-Marie

    2010-01-01

    The present study aimed to define reference values of central blood pressure (cBP) and Pulse Wave Velocity (PWV) together with 24H ABPM in healthy normotensive young adults before starring a follow-up of their CV profile modifications over time. Peer reviewed

  14. Reference values of central blood pressure and pulse wave velocity in relations with 24 hours ambulatory blood pressure monitoring in Belgian normotensive young subjects

    OpenAIRE

    Saint-Remy, Annie; Krzesinski, Jean-Marie

    2010-01-01

    The present study aimed to define reference values of central blood pressure (cBP) and Pulse Wave Velocity (PWV) together with 24H APPM in healththy normotensive young adults before starting a follow-up of their CV profile modifications over time. Peer reviewed

  15. Determinants of pulse wave velocity in healthy people and in the presence of cardiovascular risk factors: 'establishing normal and reference values'

    DEFF Research Database (Denmark)

    Hansen, Tine Willum

    2010-01-01

    Carotid-femoral pulse wave velocity (PWV), a direct measure of aortic stiffness, has become increasingly important for total cardiovascular (CV) risk estimation. Its application as a routine tool for clinical patient evaluation has been hampered by the absence of reference values. The aim of the...

  16. Porosity reduction in Nd-YAG laser welding of stainless steel and inconel alloy by using a pulsed wave

    International Nuclear Information System (INIS)

    This study investigates the influence of the Nd-YAG laser power wave mode on the porosity and mechanical properties of SUS 304L and inconel 690 weldments. Initially, a rectangular laser power waveform is specified. The output is then progressively changed from a pulsed wave mode to a continuous wave mode by reducing the value of ΔP (ΔP = Pp-Pb, where Pp is the peak power and Pb is the base power) to zero. Bead-on-plate (BOP) and butt welding are performed at a constant mean output power (1.7 kW). The BOP results demonstrate that the depth/width (D/W) ratio of both materials increases with ΔP and attains a maximum value when full penetration just occurs. The D/W ratio and the travel speed for full penetration are higher for SUS 304L than for inconel 690. In butt-welds of inconel 690 and SUS 304L, the porosity ratio decreases from 7.1% to 0.5% and from 2.1% to 0.5%, respectively, as ΔP increases from 0 to 2780 W. Therefore, the tensile strength and percentage elongation are enhanced significantly in inconel 690. The degree of porosity reduction in inconel 690 exceeds that of SUS 304L. This suggests that the viscosity of the molten inconel 690 metal is higher than that of SUS 304L. Consequently, the effect of porosity reduction due to the increase in molten metal fluidity caused by increasing ΔP is greater for inconel 690 than for SUS 304L

  17. Coupled-mode theory for electromagnetic pulse propagation in dispersive media undergoing a spatiotemporal perturbation: Exact derivation, numerical validation, and peculiar wave mixing

    Science.gov (United States)

    Sivan, Y.; Rozenberg, S.; Halstuch, A.

    2016-04-01

    We present an extension of the canonical coupled-mode theory of electromagnetic waves to the case of pulses and spatiotemporal perturbations in complex media. Unlike previous attempts to derive such a model, our approach involves no approximation, and it does not impose any restriction on the spatiotemporal profile. Moreover, the effect of modal dispersion on mode evolution and on the coupling to other modes is fully taken into account. Thus, our approach can yield any required accuracy by retaining as many terms in the expansion as needed. It also avoids various artifacts of previous derivations by introducing the correct form of the solution. We then validate the coupled-mode equations with exact numerical simulations, and we demonstrate the wide range of possibilities enabled by spatiotemporal perturbations of pulses, including pulse shortening or broadening or more complex shaping. Our formulation is valid across the electromagnetic spectrum, and it can be applied directly also to other wave systems.

  18. Bulk waves excited by a laser line pulse in a bi-layer cylinder

    Science.gov (United States)

    Pan, Y.; Chigarev, N.; Audoin, B.

    2010-03-01

    In this paper, the transient displacement excited by a laser line source is calculated for a bi-layer cylinder made of homogeneous and isotropic materials. A sample made by welding tin in a copper tube and a sample of cooper rod are considered. Experimental displacements are observed by the laser ultrasonic technique, and corresponding theoretical waveforms are calculated. Good agreement is found in the arrival time, shape and relative amplitude of various longitudinal and shear bulk waves propagating through the sample or reflected by the interface.

  19. Shaping of shock wave in aerogel irradiated by high-current pulsed electron beam

    International Nuclear Information System (INIS)

    Spread of pressure jumps excited by high-current pulsed electron beam in 0.025-0.25 g/cm3 density SiO2 aerogel was studied using laser differential interferometers and optical techniques. At the aerogel target rear side one recorded splittings-off and measured the rate of splitting fragment scattering. The rate of aerogel scattering towards the electron beam was determined. The parameters of the shock adiabat within aerogel porosity wide range were determined. The depth of the electron beam energy release zone depending on the aerogel density within 0.015-0.25 g/cm3 density range was determined experimentally. A model to describe high-porous materials was developed on the basis of the experimental data

  20. Coupling electromagnetic pulse-shaped waves into wire-like interconnection structures with a non-linear protection – Time domain calculations by the PEEC method

    Directory of Open Access Journals (Sweden)

    G. Wollenberg

    2004-01-01

    Full Text Available An interconnection system whose loads protected by a voltage suppressor and a low-pass filter against overvoltages caused by coupling pulse-shaped electromagnetic waves is analyzed. The external wave influencing the system is assumed as a plane wave with HPM form. The computation is provided by a full-wave PEEC model for the interconnection structure incorporated in the SPICE code. Thus, nonlinear elements of the protection circuit can be included in the calculation. The analysis shows intermodulation distortions and penetrations of low frequency interferences caused by intermodulations through the protection circuits. The example examined shows the necessity of using full-wave models for interconnections together with non-linear circuit solvers for simulation of noise immunity in systems protected by nonlinear devices.

  1. Induced soliton ejection from a continuous-wave source waveguided by an optical pulse soliton train

    International Nuclear Information System (INIS)

    It has been established for some time that a high-power pump can trap a probe beam of lower intensity that is simultaneously propagating in a Kerr-type optical medium, inducing a focusing of the probe with the emergence of modes displaying solitonic properties. To understand the mechanism by which such self-sustained modes are generated, and mainly the changes in probe spectrum induced by the cross-phase-modulation effect for a harmonic probe trapped by a multiplex of temporal pulses, a linear equation (for the probe) and a nonlinear Schrödinger equation (for the pump) both coupled by a cross-phase-modulation term, are considered simultaneously. In general the set of coupled probe–pump equations is not exactly tractable at any arbitrary value of the ratio of the cross-phase to the self-phase-modulation strengths. However, for certain values of this ratio, the probe modulation wavevector develops into |n, l) quantum states involving 2n + 1 soliton-shaped eigenfunctions for which the spectral properties can be characterized unambiguously. Solutions of the probe equation give evidence that the competition between the self-phase and cross-phase-modulations leads to a broadband spectrum, with the possibility of a quasi-continuum of soliton modes when the cross-phase-modulation coupling is strong enough

  2. Generation and controlling of the dispersive wave by femtosecond pulses propagating in the normal dispersion regimes of the birefringent photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper studies the generation of the dispersive wave (DW) in the normal dispersion regimes of the birefringent photonic crystal fiber (BPCF) fabricated in this work. The remarkable blue-shifted radiation is found to be generated when 30 fs pulses are input in the normal dispersion regime of the BPCF for the first time. The characteristics of the blue-shifted DW strongly depend on the polarization of the input pulse. As a result, two peaks appear in the blue-shifted region of the spectrum when the input pulses polarize along the slow axis of the BPCF. With the increase of the center wavelength of the initial input pulse, the difference between the wavelengths of the two peaks widens. The peak location in the spectrum can be explained by the phase matching condition between the DW and the input pulse. In addition, when the input polarization is set to an angle of 45° with respect to the principal axes of the BPCF, the cross-phase modulation and coherent coupling between two orthogonally polarized modes would result in pulse trapping in the BPCF. Accordingly, the DW shift toward short wavelength is restrained. The DW generation in the normal-dispersion regimes of BPCF can be controlled by the phase matching condition and polarization of the input pulse.

  3. High-efficiency generation of pulsed Lyman-α radiation by resonant laser wave mixing in low pressure Kr-Ar mixture.

    Science.gov (United States)

    Saito, Norihito; Oishi, Yu; Miyazaki, Koji; Okamura, Kotaro; Nakamura, Jumpei; Louchev, Oleg A; Iwasaki, Masahiko; Wada, Satoshi

    2016-04-01

    We report an experimental generation of ns pulsed 121.568 nm Lyman-α radiation by the resonant nonlinear four-wave mixing of 212.556 nm and 845.015 nm radiation pulses providing a high conversion efficiency 1.7x10-3 with the output pulse energy 3.6 μJ achieved using a low pressure Kr-Ar mixture. Theoretical analysis shows that this efficiency is achieved due to the advantage of using (i) the high input laser intensities in combination with (ii) the low gas pressure allowing us to avoid the onset of full-scale discharge in the laser focus. In particular, under our experimental conditions the main mechanism of photoionization caused by the resonant 2-photon 212.556 nm radiation excitation of Kr atoms followed by the 1-photon ionization leads to ≈17% loss of Kr atoms and efficiency loss only by the end of the pulse. The energy of free electrons, generated by 212.556 nm radiation via (2 + 1)-photon ionization and accelerated mainly by 845.015 nm radiation, remains during the pulse below the level sufficient for the onset of full-scale discharge by the electron avalanche. Our analysis also suggests that ≈30-fold increase of 845.015 nm pulse energy can allow one to scale up the L-α radiation pulse energy towards the level of ≈100 μJ. PMID:27137045

  4. Indices of cardiovascular function derived from peripheral pulse wave analysis using radial applanation tonometry: a measurement repeatability study.

    Science.gov (United States)

    Crilly, Mike; Coch, Christoph; Bruce, Margaret; Clark, Hazel; Williams, David

    2007-08-01

    Pulse wave analysis (PWA) using applanation tonometry is a non-invasive technique for assessing cardiovascular function. It produces three important indices: ejection duration index (ED%), augmentation index adjusted for heart rate (AIX@75), and subendocardial viability ratio (SEVR%). The aim of this study was to assess within- and between-observer repeatability of these measurements. After resting supine for 15 minutes, 20 ambulant patients (16 male) in sinus rhythm underwent four PWA measurements on a single occasion. Two nurses (A & B) independently and alternately undertook PWA measurements using the same equipment (Omron HEM-757; SphygmoCor with Millar hand-held tonometer) blind to the other nurse's PWA measurements. Within- and between-observer differences were analysed using the Bland-Altman ;limits of agreement' approach (mean difference +/- 2 standard deviations, 2SD). Mean age was 56 (blood pressure, BP 136/79; pulse rate 64). BP/PWA measurements remained stable during assessment. Based on the average of two PWA measurements the mean +/- 2SD between-observer difference in ED% was 0.3 +/- 2.0; AIX@75 1.0 +/- 3.9; and SEVR% 1.7 +/- 14.2. Based on a single PWA measurement the between-observer difference was ED% 0.3 +/- 3.3; AIX@75 1.7 +/- 6.9; and SEVR% 0.6 +/- 22.6. Within-observer differences for nurse-A were ED% 0.0 +/- 5.4; AIX@75 1.5 +/- 7.0; and SEVR% 1.7 +/- 39.0 (nurse-B: 0.1 +/- 3.8; 0.1 +/- 8.0; and 0.6 +/- 23.3, respectively). PWA demonstrates high levels of repeatability even when used by relatively inexperienced staff and has the potential to be included in the routine cardiovascular assessment of ambulant patients. PMID:17848475

  5. The venous manifestations of pulse wave encephalopathy: windkessel dysfunction in normal aging and senile dementia

    International Nuclear Information System (INIS)

    Cerebral arterial, venous and cerebrospinal fluid (CSF) pulsations are closely coupled and this produces pulsation dampening or the windkessel effect. Normal pressure hydrocephalus is a manifestation of the breakdown of this windkessel effect with altered CSF and venous pulsations being noted. The aim of this study was to show that dysfunction of the windkessel mechanism is also a component of normal aging and senile dementia. The study group comprised 24 patients classified as either early senile dementia of Alzheimer's type (SDAT) or vascular dementia (VaD). The patients with dementia were compared with 12 age-matched non-cognitively impaired subjects, and 12 normal young individuals were compared with the normal aging group. MRI flow quantification was used to measure the nonpulsatile and pulsatile components of blood flow as well as the pulsation at the tentorial incisura. With normal aging blood flow decreased but arterial pulsations increased in volume by 49% (P = 0.003). The CSF vented via the tentorial incisura does not change significantly with age and therefore increased venous pulsation is necessary. In patients with VaD the arterial pulse volume was higher by 24% and the straight sinus pulsation was higher by 57% than in normal aging subjects (P = 0.05 and P = 0.03, respectively). In patients with SDAT the total venous pulsation volumes were similar to those in normal aging subjects but there was less basal sinus pulsation. Normal aging, SDAT and VaD are associated with alterations in venous pulsation due to a breakdown of the windkessel effect. (orig.)

  6. Mechanical Stimulation (Pulsed Electromagnetic Fields "PEMF" and Extracorporeal Shock Wave Therapy "ESWT") and Tendon Regeneration: A Possible Alternative.

    Science.gov (United States)

    Rosso, Federica; Bonasia, Davide E; Marmotti, Antonio; Cottino, Umberto; Rossi, Roberto

    2015-01-01

    The pathogenesis of tendon degeneration and tendinopathy is still partially unclear. However, an active role of metalloproteinases (MMP), growth factors, such as vascular endothelial growth factor (VEGF) and a crucial role of inflammatory elements and cytokines was demonstrated. Mechanical stimulation may play a role in regulation of inflammation. In vitro studies demonstrated that both pulsed electromagnetic fields (PEMF) and extracorporeal shock wave therapy (ESWT) increased the expression of pro-inflammatory cytokine such as interleukin (IL-6 and IL-10). Moreover, ESWT increases the expression of growth factors, such as transforming growth factor β(TGF-β), (VEGF), and insulin-like growth factor 1 (IGF1), as well as the synthesis of collagen I fibers. These pre-clinical results, in association with several clinical studies, suggest a potential effectiveness of ESWT for tendinopathy treatment. Recently PEMF gained popularity as adjuvant for fracture healing and bone regeneration. Similarly to ESWT, the mechanical stimulation obtained using PEMFs may play a role for treatment of tendinopathy and for tendon regeneration, increasing in vitro TGF-β production, as well as scleraxis and collagen I gene expression. In this manuscript the rational of mechanical stimulations and the clinical studies on the efficacy of extracorporeal shock wave (ESW) and PEMF will be discussed. However, no clear evidence of a clinical value of ESW and PEMF has been found in literature with regards to the treatment of tendinopathy in human, so further clinical trials are needed to confirm the promising hypotheses concerning the effectiveness of ESWT and PEMF mechanical stimulation. PMID:26617513

  7. Mechanical stimulation (pulsed electromagnetic fields "PEMF" and extracorporeal shock wave therapy "ESWT" and tendon regeneration: a possible alternative.

    Directory of Open Access Journals (Sweden)

    Federica eRosso

    2015-11-01

    Full Text Available The pathogenesis of tendon degeneration and tendinopathy is still partially unclear. However, an active role of metalloproteinases (MMP, growth factors, such as vascular endothelial growth factor (VEGF and a crucial role of inflammatory elements and cytokines was demonstrated. Mechanical stimulation may play a role in regulation of inflammation. In vitro studies demonstrated that both pulsed electromagnetic fields (PEMF and extracorporeal shock wave therapy (ESWT increased the expression of pro-inflammatory cytokine such as interleukin (IL-6 and IL-10. Moreover ESWT increases the expression of growth factors, such as transforming growth factor beta (TGF-beta, Vascular Endothelial Growth Factor (VEGF, and insulin-like growth factor 1 (IGF1, as well as the synthesis of collagen I fibers. These pre-clinical results, in association with several clinical studies, suggest a potential effectiveness of ESWT for tendinopathy treatment. Recently PEMF gained popularity as adjuvant for fracture healing and bone regeneration. Similarly to ESWT, the mechanical stimulation obtained using PEMFs may play a role for treatment of tendinopathy and for tendon regeneration, increasing in-vitro TGF-beta production, as well as scleraxis and collagen I gene expression. In this manuscript the rational of mechanical stimulations and the clinical studies on the efficacy of extracorporeal shock wave (ESW and PEMF will be discussed. However, no clear evidence of a clinical value of ESW and PEMF has been found in literature with regards to the treatment of tendinopathy in human, so further clinical trials are needed to confirm the promising hypotheses concerning the effectiveness of ESWT and PEMF mechanical stimulation.

  8. Dynamic interference in the photoionization of He by coherent intense high-frequency laser pulses: Direct propagation of the two-electron wave packets on large spatial grids

    Science.gov (United States)

    Artemyev, Anton N.; Müller, Anne D.; Hochstuhl, David; Cederbaum, Lorenz S.; Demekhin, Philipp V.

    2016-04-01

    The direct ionization of the helium atom by intense coherent high-frequency short laser pulses is investigated theoretically from first principles. To this end, we solve numerically the time-dependent Schrödinger equation for the two-electron wave packet and its interaction with the linearly polarized pulse by the efficient time-dependent restricted-active-space configuration-interaction method (TD-RASCI). In particular, we consider photon energies which are nearly resonant for the 1 s →2 p excitation in the He+ ion. Thereby, we investigate the dynamic interference of the photoelectrons of the same kinetic energy emitted at different times along the pulse in the two-electron system. In order to enable observation of the dynamic interference in the computed spectrum, the electron wave packets were propagated on large spatial grids over long times. The computed photoionization spectra of He exhibit pronounced interference patterns the complexity of which increases with the decrease of the photon energy detuning and with the increase of the pulse intensity. Our numerical results pave the way for experimental verification of the dynamic interference effect at presently available high-frequency laser pulse sources.

  9. Extensional flow of low-viscosity fluids in capillary bridges formed by pulsed surface acoustic wave jetting

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, P K; McDonnell, A G; Prabhakar, R; Yeo, L Y; Friend, J, E-mail: james.friend@monash.edu.au [MicroNanophysics Research Laboratory, Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC 3800 (Australia); Melbourne Centre for Nanofabrication, Melbourne, VIC 3800 (Australia)

    2011-02-15

    Forming capillary bridges of low-viscosity ({approx}<10 mPa s) fluids is difficult, making the study of their capillary-thinning behavior and the measurement of the fluid's extensional viscosity difficult as well. Current techniques require some time to form a liquid bridge from the stretching of a droplet. Rapidly stretching a liquid bridge using these methods can cause its breakup if the viscosity is too low. Stretching more slowly allows the bridge to thin and break up before a suitable bridge geometry can be established to provide reliable and accurate rheological data. Using a pulsed surface acoustic wave to eject a jet from a sessile droplet, a capillary bridge may be formed in about 7.5 ms, about seven times quicker than current methods. With this approach, capillary bridges may be formed from Newtonian and non-Newtonian fluids having much lower viscosities-water, 0.04% by weight solution of high-molecular-weight (7 MDa) polystyrene in dioctyl phthalate and 0.25% fibrinogen solution in demineralized water, for example. Details of the relatively simple system used to achieve these results are provided, as are experimental results indicating deviations from a Newtonian response by the low-viscosity non-Newtonian fluids used in our study.

  10. Effects of pulsed and continuous wave 902 MHz mobile phone exposure on brain oscillatory activity during cognitive processing.

    Science.gov (United States)

    Krause, Christina M; Pesonen, Mirka; Haarala Björnberg, Christian; Hämäläinen, Heikki

    2007-05-01

    The aim of the current double-blind studies was to partially replicate the studies by Krause et al. [2000ab, 2004] and to further investigate the possible effects of electromagnetic fields (EMF) emitted by mobile phones (MP) on the event-related desynchronisation/synchronisation (ERD/ERS) EEG (electroencephalogram) responses during cognitive processing. Two groups, both consisting of 36 male participants, were recruited. One group performed an auditory memory task and the other performed a visual working memory task in six exposure conditions: SHAM (no EMF), CW (continuous wave EMF) and PM (pulse modulated EMF) during both left- and right-side exposure, while the EEG was recorded. In line with our previous studies, we observed that the exposure to EMF had modest effects on brain oscillatory responses in the alpha frequency range ( approximately 8-12 Hz) and had no effects on the behavioural measures. The effects on the EEG were, however, varying, unsystematic and inconsistent with previous reports. We conclude that the effects of EMF on brain oscillatory responses may be subtle, variable and difficult to replicate for unknown reasons. PMID:17203478

  11. Design and implementation of a smartphone-based portable ultrasound pulsed-wave Doppler device for blood flow measurement.

    Science.gov (United States)

    Huang, Chih-Chung; Lee, Po-Yang; Chen, Pay-Yu; Liu, Ting-Yu

    2012-01-01

    Blood flow measurement using Doppler ultrasound has become a useful tool for diagnosing cardiovascular diseases and as a physiological monitor. Recently, pocket-sized ultrasound scanners have been introduced for portable diagnosis. The present paper reports the implementation of a portable ultrasound pulsed-wave (PW) Doppler flowmeter using a smartphone. A 10-MHz ultrasonic surface transducer was designed for the dynamic monitoring of blood flow velocity. The directional baseband Doppler shift signals were obtained using a portable analog circuit system. After hardware processing, the Doppler signals were fed directly to a smartphone for Doppler spectrogram analysis and display in real time. To the best of our knowledge, this is the first report of the use of this system for medical ultrasound Doppler signal processing. A Couette flow phantom, consisting of two parallel disks with a 2-mm gap, was used to evaluate and calibrate the device. Doppler spectrograms of porcine blood flow were measured using this stand-alone portable device under the pulsatile condition. Subsequently, in vivo portable system verification was performed by measuring the arterial blood flow of a rat and comparing the results with the measurement from a commercial ultrasound duplex scanner. All of the results demonstrated the potential for using a smartphone as a novel embedded system for portable medical ultrasound applications. PMID:22293750

  12. Generation of Shear Alfvén Waves by Repetitive High Power Microwave Pulses Near the Electron Plasma Frequency - A laboratory study of a ``Virtual Antenna''

    Science.gov (United States)

    Wang, Yuhou; Gekelman, Walter; Pribyl, Patrick; van Compernolle, Bart; Papadopoulos, Konstantinos

    2015-11-01

    ELF / ULF waves are important in terrestrial radio communications but difficult to launch using ground-based structures due to their enormous wavelengths. In spite of this generation of such waves by field-aligned ionospheric heating modulation was first demonstrated using the HAARP facility. In the future heaters near the equator will be constructed and laboratory experiments on cross-field wave propagation could be key to the program's success. Here we report a detailed laboratory study conducted on the Large Plasma Device (LaPD) at UCLA. In this experiment, ten rapid pulses of high power microwaves (250 kW X-band) near the plasma frequency were launched transverse to the background field, and were modulated at a variable fraction (0.1-1.0) of fci. Along with bulk electron heating and density modification, the microwave pulses generated a population of fast electrons. The field-aligned current carried by the fast electrons acted as an antenna that radiated shear Alfvén waves. It was demonstrated that a controllable arbitrary frequency (f wave can be generated by this method. The radiation pattern, frequency variation and power dependence of the virtual antenna is also presented. This work is supported by an AFOSR MURI award, and conducted at the Basic Plasma Science Facility at UCLA funded by DoE and NSF.

  13. Non-Invasive Pulse Wave Analysis in a Thrombus-Free Abdominal Aortic Aneurysm after Implantation of a Nitinol Aortic Endograft

    Science.gov (United States)

    Georgakarakos, Efstratios; Argyriou, Christos; Georgiadis, George S.; Lazarides, Miltos K.

    2016-01-01

    Endovascular aneurysm repair has been associated with changes in arterial stiffness, as estimated by pulse wave velocity (PWV). This marker is influenced by the medical status of the patient, the elastic characteristics of the aneurysm wall, and the presence of intraluminal thrombus. Therefore, in order to delineate the influence of the endograft implantation in the early post-operative period, we conducted non-invasively pulse wave analysis in a male patient with an abdominal aortic aneurysm containing no intraluminal thrombus, unremarkable past medical history, and absence of peripheral arterial disease. The estimated parameters were the systolic and diastolic pressure calculated at the aortic level (central pressures), PWV, augmentation pressure (AP) and augmentation index (AI), pressure wave reflection magnitude (RM), and peripheral resistance. Central systolic and diastolic pressure decreased post-operatively. PWV showed subtle changes from 11.6 to 10.6 and 10.9 m/s at 1-week and 1-month, respectively. Accordingly, the AI decreased from 28 to 14% and continued to drop to 25%. The AP decreased gradually from 15 to 6 and 4 mmHg. The wave RM dropped from 68 to 52% at 1-month. Finally, the peripheral resistance dropped from 1.41 to 0.99 and 0.85 dyn × s × cm−5. Our example shows that the implantation of an aortic endograft can modify the pressure wave reflection over the aortic bifurcation without causing significant alterations in PWV. PMID:26793712

  14. Energetic mid-IR femtosecond pulse generation by self-defocusing soliton-induced dispersive waves in a bulk quadratic nonlinear crystal

    DEFF Research Database (Denmark)

    Zhou, Binbin; Guo, Hairun; Bache, Morten

    2015-01-01

    quality, having up to 10.5 μJ energy (6.3% conversion). The mid-IR pulses are dispersive waves phase-matched to near-IR self-defocusing solitons created by the induced self-defocusing cascaded nonlinearity. This process is filament-free and the input pulse energy can therefore be scaled arbitrarily by......Generating energetic femtosecond mid-IR pulses is crucial for ultrafast spectroscopy, and currently relies on parametric processes that, while efficient, are also complex. Here we experimentally show a simple alternative that uses a single pump wavelength without any pump synchronization and...... without critical phase-matching requirements. Pumping a bulk quadratic nonlinear crystal (unpoled LiNbO3 cut for noncritical phase-mismatched interaction) with sub-mJ near-IR 50-fs pulses, tunable and broadband (∼ 1,000 cm−1) mid-IR pulses around 3.0 μm are generated with excellent spatio-temporal pulse...

  15. Energetic mid-IR femtosecond pulse generation by self-defocusing soliton-induced dispersive waves in a bulk quadratic nonlinear crystal

    CERN Document Server

    Zhou, B B; Bache, M

    2014-01-01

    Generating energetic femtosecond mid-IR pulses is crucial for ultrafast spectroscopy, and currently relies on parametric processes that, while efficient, are also complex. Here we experimentally show a simple alternative that uses a single pump wavelength without any pump synchronization and without critical phase-matching requirements. Pumping a bulk quadratic nonlinear crystal (unpoled LiNbO$_3$ cut for noncritical phase-mismatched interaction) with sub-mJ near-IR 50-fs pulses, tunable and broadband ($\\sim 1,000$ cm$^{-1}$) mid-IR pulses around $3.0~\\mu\\rm m$ are generated with excellent spatio-temporal pulse quality, having up to 10.5 $\\mu$J energy (6.3% conversion). The mid-IR pulses are dispersive waves phase-matched to near-IR self-defocusing solitons created by the induced self-defocusing cascaded nonlinearity. This process is filament-free and the input pulse energy can therefore be scaled arbitrarily by using large-aperture crystals. The technique can readily be implemented with other crystals and la...

  16. Observation of water-shock-wave propagation emanated from the roughened optical fiber end surface by the pulse laser energy input

    Science.gov (United States)

    Nakahara, Motonao; Nagayama, Kunihito

    1999-06-01

    Pressure enhancement of the generated shock waves in water has been found, when pulse laser energy is transmitted through an optical fiber whose end surface is intentionally roughened. More effective high-pressure shock generation can be possible by the aluminum coating on the roughened fiber surface. In case of the moderate laser energy of about 50 mJ input to the fiber, it is found that the phenomena are dependent on (1) the roughness, (2) the fiber diameter, and (3) the ambient medium. Shock wave generation can be detected successively by the laser input, but found to degrade down. Cavitation bubbles have also been observed after each shot. When the fiber end is in air, an intense and long-stretched flash can be observed. We have observed the phenomena by the pulse laser shadowgraphy.

  17. Dissipative rogue waves induced by long-range chaotic multi-pulse interactions in a fiber laser with a topological insulator-deposited microfiber photonic device.

    Science.gov (United States)

    Liu, Meng; Cai, Ze-Rong; Hu, Song; Luo, Ai-Ping; Zhao, Chu-Jun; Zhang, Han; Xu, Wen-Cheng; Luo, Zhi-Chao

    2015-10-15

    We reported on the generation of dissipative rogue waves (DRWs) induced by long-range chaotic multi-pulse interactions in a fiber laser based on a topological insulator (TI)-deposited microfiber photonic device. By virtue of the simultaneous saturable absorption effect and high nonlinearity provided by the TI-deposited microfiber, a localized, chaotic multi-pulse wave packet with strong long-range nonlinear interactions could be obtained, which gives rise to the formation of DRWs. The results might enhance the understanding of DRWs in optical systems, and further demonstrated that the TI-deposited microfiber could be considered as an excellent photonic device with both saturable absorption and highly nonlinear effects for the application field of nonlinear optics. PMID:26469615

  18. Mechanical Stimulation (Pulsed Electromagnetic Fields “PEMF” and Extracorporeal Shock Wave Therapy “ESWT”) and Tendon Regeneration: A Possible Alternative

    OpenAIRE

    Federica eRosso; Davide Edoardo Bonasia; Antonio eMarmotti; Umberto eCottino; Roberto eRossi

    2015-01-01

    The pathogenesis of tendon degeneration and tendinopathy is still partially unclear. However, an active role of metalloproteinases (MMP), growth factors, such as vascular endothelial growth factor (VEGF) and a crucial role of inflammatory elements and cytokines was demonstrated. Mechanical stimulation may play a role in regulation of inflammation. In vitro studies demonstrated that both pulsed electromagnetic fields (PEMF) and extracorporeal shock wave therapy (ESWT) increased the expression ...

  19. Effect of Pulsed Wave Low-Level Laser Therapy on Tibial Complete Osteotomy Model of Fracture Healing With an Intramedullary Fixation

    OpenAIRE

    Mostafavinia, Atarodalsadat; Masteri Farahani, Reza; Abbasian, Mohammadreza; Vasheghani Farahani, Mohammadmehdi; Fridoni, Mohammadjavad; Zandpazandi, Sara; GHOREISHI, Seyed Kamran; Abdollahifar, Mohammad Amin; Pouriran, Ramin; Bayat, Mohammad

    2015-01-01

    Background: Fractures pose a major worldwide challenge to public health, causing tremendous disability for the society and families. According to recent studies, many in vivo and in vitro experiments have shown the positive effects of PW LLLT on osseous tissue. Objectives: The aim of this study was to evaluate the outcome of infrared pulsed wave low-level laser therapy (PW LLLT) on the fracture healing process in a complete tibial osteotomy in a rat model, which was stabilized by an intramedu...

  20. Ethnic differences in and childhood influences on early adult pulse wave velocity: the Determinants of Adolescent, Now Young Adult, Social Wellbeing, and Health longitudinal study

    OpenAIRE

    Cruickshank, J Kennedy; Silva, Maria J.; Molaodi, Oarabile R.; Enayat, Zinat E.; Cassidy, Aidan; Karamanos, Alexis; Read, Ursula M.; Faconti, Luca; Dall, Philippa; Stansfield, Ben; Harding, Seeromanie

    2016-01-01

    Early determinants of aortic stiffness as pulse wave velocity are poorly understood. We tested how factors measured twice previously in childhood in a multiethnic cohort study, particularly body mass, blood pressure, and objectively assessed physical activity affected aortic stiffness in young adults. Of 6643 London children, aged 11 to 13 years, from 51 schools in samples stratified by 6 ethnic groups with different cardiovascular risk, 4785 (72%) were seen again at aged 14 to 16 years. In 2...

  1. Ethnic differences in and childhood influences on early adult pulse wave velocity:The determinants of adolescent, now young adult, social wellbeing, and health longitudinal study

    OpenAIRE

    Cruickshank, J Kennedy; Silva, Maria J.; Molaodi, Oarabile R.; Enayat, Zinat E.; Cassidy, Aidan; Karamanos, Alexis; Read, Ursula M.; Faconti, Luca; Dall, Philippa; Stansfield, Ben; Harding, Seeromanie

    2016-01-01

    Early determinants of aortic stiffness as pulse wave velocity are poorly understood. We tested how factors measured twice previously in childhood in a multiethnic cohort study, particularly body mass, blood pressure, and objectively assessed physical activity affected aortic stiffness in young adults. Of 6643 London children, aged 11 to 13 years, from 51 schools in samples stratified by 6 ethnic groups with different cardiovascular risk, 4785 (72%) were seen again at aged 14 to 16 years. In 2...

  2. On mean wind and turbulence profile measurements from ground-based wind lidars:limitations in time and space resolution with continuous wave and pulsed lidar systems

    OpenAIRE

    Mikkelsen, Torben

    2009-01-01

    Two types of wind lidar?s have become available for ground-based vertical mean wind and turbulence profiling. A continuous wave (CW) wind lidar, and a pulsed wind lidar. Although they both are build upon the same recent 1.55 μ telecom fibre technology, they possess fundamental differences between their temporal and spatial resolution capabilities. A literature review of the two lidar systems spatial and temporal resolution characteristics will be presented, and the implication for the two lid...

  3. Exposure of the thorax to a sublethal blast wave causes a hydrodynamic pulse that leads to perivenular inflammation in the brain.

    Science.gov (United States)

    Simard, J Marc; Pampori, Adam; Keledjian, Kaspar; Tosun, Cigdem; Schwartzbauer, Gary; Ivanova, Svetlana; Gerzanich, Volodymyr

    2014-07-15

    Traumatic brain injury (TBI) caused by an explosive blast (blast-TBI) is postulated to result, in part, from transvascular transmission to the brain of a hydrodynamic pulse (a.k.a., volumetric blood surge, ballistic pressure wave, hydrostatic shock, or hydraulic shock) induced in major intrathoracic blood vessels. This mechanism of blast-TBI has not been demonstrated directly. We tested the hypothesis that a blast wave impacting the thorax would induce a hydrodynamic pulse that would cause pathological changes in the brain. We constructed a Thorax-Only Blast Injury Apparatus (TOBIA) and a Jugular-Only Blast Injury Apparatus (JOBIA). TOBIA delivered a collimated blast wave to the right lateral thorax of a rat, precluding direct impact on the cranium. JOBIA delivered a blast wave to the fluid-filled port of an extracorporeal intravenous infusion device whose catheter was inserted retrograde into the jugular vein, precluding lung injury. Long Evans rats were subjected to sublethal injury by TOBIA or JOBIA. Blast injury induced by TOBIA was characterized by apnea and diffuse bilateral hemorrhagic injury to the lungs associated with a transient reduction in pulse oximetry signals. Immunolabeling 24 h after injury by TOBIA showed up-regulation of tumor necrosis factor alpha, ED-1, sulfonylurea receptor 1 (Sur1), and glial fibrillary acidic protein in veins or perivenular tissues and microvessels throughout the brain. The perivenular inflammatory effects induced by TOBIA were prevented by ligating the jugular vein and were reproduced using JOBIA. We conclude that blast injury to the thorax leads to perivenular inflammation, Sur1 up-regulation, and reactive astrocytosis resulting from the induction of a hydrodynamic pulse in the vasculature. PMID:24673157

  4. Coupled-mode theory for electromagnetic pulse propagation in dispersive media undergoing a spatio-temporal perturbation - exact derivation, numerical validation and peculiar wave mixing

    CERN Document Server

    Sivan, Y; Halstuch, A

    2016-01-01

    We present an extension of the canonical coupled mode theory of electromagnetic waves to the case of pulses and spatio-temporal perturbations in complex media. Unlike previous attempts to derive such a model, our approach involves no approximation, and does not impose any restriction on the spatio-temporal profile. Moreover, the effect of modal dispersion on mode evolution and on the coupling to other modes is fully taken into account. Thus, our approach can yield any required accuracy by retaining as many terms in the expansion as needed. It also avoids various artifacts of previous derivations by introducing the correct form of the solution. We then provide what is, to the best of our knowledge, the first ever validation of the coupled mode equations with exact numerical simulations, and demonstrate the wide range of possibilities enabled by spatio-temporal perturbations of pulses, including pulse shortening or broadening or more complex shaping. Our formulation is valid across the electromagnetic spectrum,...

  5. Photoelectron circular dichroism in the multiphoton ionization by short laser pulses. I. Propagation of single-active-electron wave packets in chiral pseudo-potentials

    International Nuclear Information System (INIS)

    A theoretical method to study the angle-resolved multiphoton ionization of polyatomic molecules is developed. It is based on the time-dependent formulation of the Single Center (TDSC) method and consists in the propagation of single-active-electron wave packets in the effective molecular potentials in the presence of intense laser pulses. For this purpose, the time-dependent Schrödinger equation for one electron, moving in a molecular field and interacting with an arbitrary laser pulse, is solved in spherical coordinates by an efficient numerical approach. As a test, the method is applied to the one- and two-photon ionizations of a model methane-like chiral system by circularly polarized short intense high-frequency laser pulses. Thereby, we analyze the photoelectron circular dichroism (PECD) in the momentum distribution. The considered model application illustrates the capability of the TDSC method to study multiphoton PECD in fixed-in-space and randomly oriented chiral molecules

  6. Effective transvascular drug delivery to glioma in rats by using a pulsed laser-induced photomechanical wave (Conference Presentation)

    Science.gov (United States)

    Akutsu, Yusuke; Sato, Shunichi; Tomiyama, Arata; Tsunoi, Yasuyuki; Kawauchi, Satoko; Mori, Kentaro; Terakawa, Mitsuhiro

    2016-03-01

    Glioma is one of the most aggressive cancers, for which efficacy of conventional chemotherapy is often limited due to the blood-tumor barrier (BTB). Thus, the development of a method for enhancing the BTB permeability is strongly desired. In this study, we applied a photomechanical wave (PMW), which was generated by the irradiation of a light-absorbing material with a nanosecond laser pulse, to transiently open the BTB in a rat intracranial glioma model using C6 cells. A tumor was grown in the both hemispheres, and a solution of Evans blue (EB), as a test drug, was injected into the tail vein. Thereafter, we applied a PMW generated at a laser fluence of 0.2 J/cm2 (averaged peak pressure, ~27 MPa), 0.4 J/cm2 (~54 MPa) or 0.6 J/cm2 (~78MPa), to one hemisphere through the cranial window, while the other hemisphere served as a control. Four hours later, the rat was perfused, and we compared intensity distributions of EB fluorescence between the both hemispheres. Intensities of EB fluorescence both in the peritumoral and tumor core regions were increased with increasing the laser fluence, but hemorrhage was observed at the highest fluence. Thus, 0.4 J/cm2 would be optimum for efficient and safe BTB opening. On the basis of fluorescence microscopy with the use of enhanced green fluorescent protein-expressing C6 cells, we confirmed that a drug was delivered into targeted glioma cells in the peritumoral region. These results show the validity of the present transvascular drug delivery method to glioma.

  7. Identifying coronary artery disease in men with type 2 diabetes: osteoprotegerin, pulse wave velocity, and other biomarkers of cardiovascular risk.

    LENUS (Irish Health Repository)

    Davenport, Colin

    2012-02-01

    OBJECTIVES: In patients with type 2 diabetes, high serum levels of osteoprotegerin (OPG) have been associated with a greater risk of cardiovascular events. However, it remains unclear how well OPG performs when compared with traditional biomarkers of cardiovascular risk such as high-sensitivity C-reactive protein (hsCRP). Furthermore, OPG levels are also high in the presence of diabetes-related microvascular disease, and it is unclear whether OPG can distinguish microvascular disease from large-vessel atherosclerosis. The first aim of this study was to compare OPG levels against other biomarkers of cardiovascular risk in the identification of patients with documented multivessel coronary artery disease (CAD). The second aim was to compare OPG levels in patients with microvascular complications (microalbuminuria) against those with established CAD. METHODS: Three groups of male patients with type 2 diabetes were recruited: patients without microvascular complications or large-vessel atherosclerosis (n = 24), patients with microalbuminuria only (n = 23), and patients with microalbuminuria and documented multivessel CAD (n = 25). OPG, hsCRP, interleukin 6, urate, and pulse wave velocity were measured. RESULTS: Serum OPG levels were significantly higher in patients with a combination of microalbuminuria and CAD than in those with microalbuminuria alone. There were no significant differences in any of the other biomarkers between the groups. CONCLUSION: OPG was found to be superior to the other biomarkers studied in identifying patients with documented CAD. The presence of CAD was a greater determinant of serum OPG levels than microalbuminuria in our population. These findings support the use of OPG as a biomarker of cardiovascular risk.

  8. A comparative study of the effect of coronary atherosclerosis and age on aortic and pulmonary arterial pulse wave velocity

    International Nuclear Information System (INIS)

    The effect of coronary artery disease (CAD) and age on aortic (AO-PWV) and pulmonary arterial pulse wave velocity (PA-PWV) was studied. Aortic and pulmonary arterial pressure were measured at two sites (ascending and abdominal aorta, and the main pulmonary trunk and one of its principle branches, respectively) using a catheter-tip micromanometer in 24 patients divided in two groups. Control group (n=12) consisted of patients with normal coronaries, while the CAD group (n=12) consisted of patients with coronary artery disease estimated by coronary angiography. The interval between these two sites was determined by measuring the withdrawal distance of the microtip-catheter. AO-PWV was significantly higher (p<0.02) in the CAD group (12.0±4.1 m/sec) than in the control group (8.2±2.7 m/sec). There was no significant difference between the two groups in PA-PWV. AO-PWV was significantly (r=0.731, p<0.01) increased with age in the control group, while no significant correlation between the two was observed in the CAD group. There was no significant correlation between PA-PWV and age in control group. The results of this study indicate that only coronary atherosclerosis and age have significant predictive value regarding AO-PWV, but there was no significant correlation with PA-PWV for any of these parameters. The PA-PWV invasively measured in the 12 control subjects in this study was 2.3±0.7 m/sec, which is very close to values reported in the recent literatures using MRI. (author)

  9. Comparison between continuous non-invasive estimated cardiac output by pulse wave transit time and thermodilution method

    Directory of Open Access Journals (Sweden)

    Ashish C Sinha

    2014-01-01

    Full Text Available Aims and Objectives: Cardiac output (CO measurement is essential for many therapeutic decisions in anesthesia and critical care. Most available non-invasive CO measuring methods have an invasive component. We investigate "pulse wave transit time" (estimated continuous cardiac output [esCCO] a method of CO measurement that has no invasive component to its use. Materials and Methods: After institutional ethical committee approval, 14 adult (21-85 years patients undergoing surgery and requiring pulmonary artery catheter (PAC for measuring CO, were included. Postoperatively CO readings were taken simultaneously with thermodilution (TD via PAC and esCCO, whenever a change in CO was expected due to therapeutic interventions. Both monitoring methods were continued until patients′ discharge from the Intensive Care Unit and observer recording values using TD method was blinded to values measured by esCCO system. Results: Three hundred and one readings were obtained simultaneously from both methods. Correlation and concordance between the two methods was derived using Bland-Altman analysis. Measured values showed significant correlation between esCCO and TD ( r = 0.6, P < 0.001, 95% confidence limits of 0.51-0.68. Mean and (standard deviation for bias and precision were 0.13 (2.27 L/min and 6.56 (2.19 L/min, respectively. The 95% confidence interval for bias was - 4.32 to 4.58 L/min and for precision 2.27 to10.85 L/min. Conclusions: Although, esCCO is the only true non-invasive continuous CO monitor available and even though its values change proportionately to TD method (gold standard with the present degree of error its utility for clinical/therapeutic decision-making is questionable.

  10. Mathematical Modeling of Pulse Wave Based on Lognormal Function%基于 Lognormal 函数的脉搏波数学建模

    Institute of Scientific and Technical Information of China (English)

    赵海; 窦圣昶; 李大舟; 陈星池

    2016-01-01

    对健康的日常监测,时间长,数据量大。为了简化数据量,分析了现有的使用2~4个高斯函数拟合脉搏波的脉搏波数学建模方法,在此基础上,提出了 Lognormal 函数模型的数学建模方法。使用 4个Lognormal 函数对脉搏波的一个周期进行拟合建模,以脉搏波的生理特性为基础调整 4个 Lognormal 函数的起始时间点,并对其性能进行了分析对比。结果表明,与现有方法相比,Lognormal 函数模型不仅有更高的拟合精确度,而且有更优的计算复杂度,更适合以日常健康监测为目的的体域网健康大数据应用。%Daily monitoring health status needs long time,so the amount of health data is massive.In order to simplify the data,the existing mathematical methods of modeling pulse wave were analyzed which use two to four Gauss function to fit the pulse wave.Then,the mathematical modeling method of pulse wave based on Lognormal function was presented.A cycle of pulse wave was modeled by using four Lognormal functions.The starting time points of the four Lognormal functions were adjusted based on the physiological characteristics of the pulse wave, and the performance of the model was analyzed and compared with the existing methods.The results show that,compared with the existing methods,the Lognormal function model not only has a higher fitting accuracy,but also has better computational complexity,thus being more suitable for the big data application to daily health monitor in the body area network.

  11. Spin wave and percolation studies in epitaxial La2/3Sr1/3MnO3 thin films grown by pulsed laser deposition

    Science.gov (United States)

    Ettayfi, A.; Moubah, R.; Hlil, E. K.; Colis, S.; Lenertz, M.; Dinia, A.; Lassri, H.

    2016-07-01

    We investigate the magnetic and transport properties of high quality La2/3Sr1/3MnO3 thin films grown by pulsed laser deposition. X-ray diffraction shows that the deposited films are epitaxial with the expected pseudo-cubic structure. Using the spin wave theory, the temperature dependence of magnetization was satisfactory modeled at low temperature, in which several fundamental magnetic parameters were obtained (spin wave stiffness, exchange constants, Fermi wave-vector, Mn-Mn interatomic distance). The transport properties were studied via the temperature dependence of electrical resistivity [ρ(T)], which shows a peak at Curie temperature due to metal to insulator transition. The percolation theory was used to simulate ρ(T) in both the ferromagnetic and paramagnetic phases. Reasonable agreement with the experimental data is reported.

  12. Spin wave mediated unidirectional vortex core reversal by two orthogonal monopolar field pulses: The essential role of three-dimensional magnetization dynamics

    Science.gov (United States)

    Noske, Matthias; Stoll, Hermann; Fähnle, Manfred; Gangwar, Ajay; Woltersdorf, Georg; Slavin, Andrei; Weigand, Markus; Dieterle, Georg; Förster, Johannes; Back, Christian H.; Schütz, Gisela

    2016-05-01

    Scanning transmission x-ray microscopy is employed to investigate experimentally the reversal of the magnetic vortex core polarity in cylindrical Ni81Fe19 nanodisks triggered by two orthogonal monopolar magnetic field pulses with peak amplitude B0, pulse length τ = 60 ps , and delay time Δ t in the range from - 400 ps to + 400 ps between the two pulses. The two pulses are oriented in-plane in the x- and y-directions. We have experimentally studied vortex core reversal as a function of B0 and Δ t . The resulting phase diagram shows large regions of unidirectional vortex core switching where the switching threshold is modulated due to resonant amplification of azimuthal spin waves. The switching behavior changes dramatically depending on whether the first pulse is applied in the x- or the y-direction. This asymmetry can be reproduced by three-dimensional micromagnetic simulations but not by two-dimensional simulations. This behavior demonstrates that in contrast to the previous experiments on vortex core reversal, the three-dimensionality in the dynamics is essential here.

  13. Consistency of aortic distensibility and pulse wave velocity estimates with respect to the Bramwell-Hill theoretical model: a cardiovascular magnetic resonance study

    Directory of Open Access Journals (Sweden)

    De Cesare Alain

    2011-01-01

    Full Text Available Abstract Background Arterial stiffness is considered as an independent predictor of cardiovascular mortality, and is increasingly used in clinical practice. This study aimed at evaluating the consistency of the automated estimation of regional and local aortic stiffness indices from cardiovascular magnetic resonance (CMR data. Results Forty-six healthy subjects underwent carotid-femoral pulse wave velocity measurements (CF_PWV by applanation tonometry and CMR with steady-state free-precession and phase contrast acquisitions at the level of the aortic arch. These data were used for the automated evaluation of the aortic arch pulse wave velocity (Arch_PWV, and the ascending aorta distensibility (AA_Distc, AA_Distb, which were estimated from ascending aorta strain (AA_Strain combined with either carotid or brachial pulse pressure. The local ascending aorta pulse wave velocity AA_PWVc and AA_PWVb were estimated respectively from these carotid and brachial derived distensibility indices according to the Bramwell-Hill theoretical model, and were compared with the Arch_PWV. In addition, a reproducibility analysis of AA_PWV measurement and its comparison with the standard CF_PWV was performed. Characterization according to the Bramwell-Hill equation resulted in good correlations between Arch_PWV and both local distensibility indices AA_Distc (r = 0.71, p AA_Distb (r = 0.60, p Arch_PWV and both theoretical local indices AA_PWVc (r = 0.78, p AA_PWVb (r = 0.78, p Arch_PWV was well related to CF_PWV (r = 0.69, p Conclusions The present work confirmed the consistency and robustness of the regional index Arch_PWV and the local indices AA_Distc and AA_Distb according to the theoretical model, as well as to the well established measurement of CF_PWV, demonstrating the relevance of the regional and local CMR indices.

  14. Investigation of acoustic waves generated in an elastic solid by a pulsed ion beam and their application in a FIB based scanning ion acoustic microscope

    Energy Technology Data Exchange (ETDEWEB)

    Akhmadaliev, C.

    2004-12-01

    The aim of this work is to investigate the acoustic wave generation by pulsed and periodically modulated ion beams in different solid materials depending on the beam parameters and to demonstrate the possibility to apply an intensity modulated focused ion beam (FIB) for acoustic emission and for nondestructive investigation of the internal structure of materials on a microscopic scale. The combination of a FIB and an ultrasound microscope in one device can provide the opportunity of nondestructive investigation, production and modification of micro- and nanostructures simultaneously. This work consists of the two main experimental parts. In the first part the process of elastic wave generation during the irradiation of metallic samples by a pulsed beam of energetic ions was investigated in an energy range from 1.5 to 10 MeV and pulse durations of 0.5-5 {mu}s, applying ions with different masses, e.g. oxygen, silicon and gold, in charge states from 1{sup +} to 4{sup +}. The acoustic amplitude dependence on the ion beam parameters like the ion mass and energy, the ion charge state, the beam spot size and the pulse duration were of interest. This work deals with ultrasound transmitted in a solid, i.e. bulk waves, because of their importance for acoustic transmission microscopy and nondestructive inspection of internal structure of a sample. The second part of this work was carried out using the IMSA-100 FIB system operating in an energy range from 30 to 70 keV. The scanning ion acoustic microscope based on this FIB system was developed and tested. (orig.)

  15. Investigation of acoustic waves generated in an elastic solid by a pulsed ion beam and their application in a FIB based scanning ion acoustic microscope

    International Nuclear Information System (INIS)

    The aim of this work is to investigate the acoustic wave generation by pulsed and periodically modulated ion beams in different solid materials depending on the beam parameters and to demonstrate the possibility to apply an intensity modulated focused ion beam (FIB) for acoustic emission and for nondestructive investigation of the internal structure of materials on a microscopic scale. The combination of a FIB and an ultrasound microscope in one device can provide the opportunity of nondestructive investigation, production and modification of micro- and nanostructures simultaneously. This work consists of the two main experimental parts. In the first part the process of elastic wave generation during the irradiation of metallic samples by a pulsed beam of energetic ions was investigated in an energy range from 1.5 to 10 MeV and pulse durations of 0.5-5 μs, applying ions with different masses, e.g. oxygen, silicon and gold, in charge states from 1+ to 4+. The acoustic amplitude dependence on the ion beam parameters like the ion mass and energy, the ion charge state, the beam spot size and the pulse duration were of interest. This work deals with ultrasound transmitted in a solid, i.e. bulk waves, because of their importance for acoustic transmission microscopy and nondestructive inspection of internal structure of a sample. The second part of this work was carried out using the IMSA-100 FIB system operating in an energy range from 30 to 70 keV. The scanning ion acoustic microscope based on this FIB system was developed and tested. (orig.)

  16. Wave

    OpenAIRE

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many times smaller it remains very high. For example, whilst there is enough potential wave power off the UK to supply the electricity demands several times over, the economically recoverable resource for t...

  17. Wave

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many...... times smaller it remains very high. For example, whilst there is enough potential wave power off the UK to supply the electricity demands several times over, the economically recoverable resource for the UK is estimated at 25% of current demand; a lot less, but a very substantial amount nonetheless....

  18. Method of optical self-mixing for pulse wave transit time in comparison with other methods and correlation with blood pressure

    Science.gov (United States)

    Meigas, Kalju; Lass, Jaanus; Kattai, Rain; Karai, Deniss; Kaik, Juri

    2004-07-01

    This paper is a part of research to develop convenient method for continuous monitoring of arterial blood pressure by non-invasive and non-oscillometric way. A simple optical method, using self-mixing in a diode laser, is used for detection of skin surface vibrations near the artery. These vibrations, which can reveal the pulsate propagation of blood pressure waves along the vasculature, are used for pulse wave registration. The registration of the Pulse Wave Transit Time (PWTT) is based on computing the time delay in different regions of the human body using an ECG as a reference signal. In this study, the comparison of method of optical self-mixing with other methods as photoplethysmographic (PPG) and bioimpedance (BI) for PWTT is done. Also correlation of PWTT, obtained with different methods, with arterial blood pressure is calculated. In our study, we used a group of volunteers (34 persons) who made the bicycle exercise test. The test consisted of cycling sessions of increasing workloads during which the HR changed from 60 to 180 beats per minute. In addition, a blood pressure (NIBP) was registered with standard sphygmomanometer once per minute during the test and all NIBP measurement values were synchronized to other signals to find exact time moments where the systolic blood pressure was detected (Korotkoff sounds starting point). Computer later interpolated the blood pressure signal in order to get individual value for every heart cycle. The other signals were measured continuously during all tests. At the end of every session, a recovery period was included until person's NIBP and heart rate (HR) normalized. As a result of our study it turned out that time intervals that were calculated from plethysmographic (PPG) waveforms were in the best correlation with systolic blood pressure. The diastolic pressure does not correlate with any of the parameters representing PWTT. The pulse wave signals measured by laser and piezoelectric transducer are very similar

  19. A two-dimensional analysis of the sensitivity of a pulse first break to wave speed contrast on a scale below the resolution length of ray tomography.

    Science.gov (United States)

    Willey, Carson L; Simonetti, Francesco

    2016-06-01

    Mapping the speed of mechanical waves traveling inside a medium is a topic of great interest across many fields from geoscience to medical diagnostics. Much work has been done to characterize the fidelity with which the geometrical features of the medium can be reconstructed and multiple resolution criteria have been proposed depending on the wave-matter interaction model used to decode the wave speed map from scattering measurements. However, these criteria do not define the accuracy with which the wave speed values can be reconstructed. Using two-dimensional simulations, it is shown that the first-arrival traveltime predicted by ray theory can be an accurate representation of the arrival of a pulse first break even in the presence of diffraction and other phenomena that are not accounted for by ray theory. As a result, ray-based tomographic inversions can yield accurate wave speed estimations also when the size of a sound speed anomaly is smaller than the resolution length of the inversion method provided that traveltimes are estimated from the signal first break. This increased sensitivity however renders the inversion more susceptible to noise since the amplitude of the signal around the first break is typically low especially when three-dimensional anomalies are considered. PMID:27369139

  20. Backward-Propagating MeV Electrons in Ultra-Intense Laser Interactions: Standing Wave Acceleration and Coupling to the Reflected Laser Pulse

    CERN Document Server

    Orban, Chris; Chowdhury, Enam D; Nees, John A; Frische, Kyle; Roquemore, W Melvyn

    2014-01-01

    Laser-accelerated electron beams have been created at a kHz repetition rate from the reflection of intense ($\\sim10^{18}$ W/cm$^2$), 30 fs laser pulses focused on a continuous water-jet in an experiment at the Air Force Research Laboratory. This paper investigates Particle-In-Cell (PIC) simulations of the laser-target interaction to identify the physical mechanisms of electron acceleration in this experiment. We find that the standing-wave pattern created by the overlap of the incident and reflected laser is particularly important because this standing wave "injects" electrons into the reflected laser pulse where the electrons are further accelerated. We identify two regimes of standing wave acceleration: a highly relativistic case ($a_0~\\geq~1$), and a moderately relativistic case ($a_0~\\sim~0.5$) which operates over a larger fraction of the laser period. Previous work by other groups investigated the highly relativistic case for its usefulness in launching electrons in the forward direction. We extend this ...

  1. Finite element method (FEM) model of the mechanical stress on phospholipid membranes from shock waves produced in nanosecond electric pulses (nsEP)

    Science.gov (United States)

    Barnes, Ronald; Roth, Caleb C.; Shadaram, Mehdi; Beier, Hope; Ibey, Bennett L.

    2015-03-01

    The underlying mechanism(s) responsible for nanoporation of phospholipid membranes by nanosecond pulsed electric fields (nsEP) remains unknown. The passage of a high electric field through a conductive medium creates two primary contributing factors that may induce poration: the electric field interaction at the membrane and the shockwave produced from electrostriction of a polar submersion medium exposed to an electric field. Previous work has focused on the electric field interaction at the cell membrane, through such models as the transport lattice method. Our objective is to model the shock wave cell membrane interaction induced from the density perturbation formed at the rising edge of a high voltage pulse in a polar liquid resulting in a shock wave propagating away from the electrode toward the cell membrane. Utilizing previous data from cell membrane mechanical parameters, and nsEP generated shockwave parameters, an acoustic shock wave model based on the Helmholtz equation for sound pressure was developed and coupled to a cell membrane model with finite-element modeling in COMSOL. The acoustic structure interaction model was developed to illustrate the harmonic membrane displacements and stresses resulting from shockwave and membrane interaction based on Hooke's law. Poration is predicted by utilizing membrane mechanical breakdown parameters including cortical stress limits and hydrostatic pressure gradients.

  2. Backward-propagating MeV electrons in ultra-intense laser interactions: Standing wave acceleration and coupling to the reflected laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Orban, Chris, E-mail: orban@physics.osu.edu; Feister, Scott [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Morrison, John T. [National Research Council, Washington, DC 20001 (United States); Intense Energy Solutions, LLC, Plain City, Ohio 43064 (United States); Chowdhury, Enam A. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Center for Ultra-Fast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Nees, John A. [Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Intense Energy Solutions, LLC, Plain City, Ohio 43064 (United States); Frische, Kyle [Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Roquemore, W. M. [Air Force Research Laboratory, Dayton, Ohio 45433 (United States)

    2015-02-15

    Laser-accelerated electron beams have been created at a kHz repetition rate from the reflection of intense (∼10{sup 18 }W/cm{sup 2}), ∼40 fs laser pulses focused on a continuous water-jet in an experiment at the Air Force Research Laboratory. This paper investigates Particle-in-Cell simulations of the laser-target interaction to identify the physical mechanisms of electron acceleration in this experiment. We find that the standing-wave pattern created by the overlap of the incident and reflected laser is particularly important because this standing wave can “inject” electrons into the reflected laser pulse where the electrons are further accelerated. We identify two regimes of standing wave acceleration: a highly relativistic case (a{sub 0} ≥ 1), and a moderately relativistic case (a{sub 0} ∼ 0.5) which operates over a larger fraction of the laser period. In previous studies, other groups have investigated the highly relativistic case for its usefulness in launching electrons in the forward direction. We extend this by investigating electron acceleration in the specular (back reflection) direction and over a wide range of intensities (10{sup 17}–10{sup 19 }W cm{sup −2})

  3. 辐射式核电磁脉冲模拟器快沿脉冲源研制%Development of Fast-Rising Pulse Source for Radiating-Wave Nuclear Electromagnetic Pulse Simulator

    Institute of Scientific and Technical Information of China (English)

    王赟; 范丽思; 成伟; 王民全; 刘朝阳

    2015-01-01

    根据辐射式核电磁脉冲模拟器对脉冲源的设计要求,研制一种由 Marx发生器和锐化装置构成的快沿脉冲源.Marx发生器为双边充电回路,由最大值高压无感电容器、电磁铁机械运动轨道触发开关、气体火花间隙开关及电阻等构成;锐化装置由分布参数同轴锐化电容和自击穿火花间隙锐化开关构成.对快沿脉冲源充放电等效回路进行Pspice模拟仿真,并通过试验测得实际的模拟器辐射场波形,结果表明:实测波形与仿真波形一致性较好,辐射式模拟器在距天线口径面3 m位置处产生上升时间小于5 ns、脉宽300多纳秒、峰值场强大于50 kV/m 的双指数脉冲场.实际研制的快沿脉冲源基本上满足了设计指标要求,为下一步改进优化辐射式模拟器奠定了基础.%According to the design requirement of pulse source used by the radiating-wave nuclear electromagnetic pulse (NEMP)simulator,a fast rising pulse source which consists of a Marx generator and sharpening equipment was developed.The Marx generator is bipolar charged and composed of the maximum high voltage non-inductive capacitor, electromagnet mechanical movement track trigger switch,gas spark gap switch and resistors,etc.Sharpening equipment is composed of sharpening coaxial capacitance with distributional parameters and self-breakdown spark gap switch.The Pspice simulation was carried out on the equivalent circuit of fast rising pulse source and the radiating waveform of simulator was measured through experiments.The results show that the measured waveform is similar to the simulated waveform.The radiating-wave nuclear electromagnetic pulse simulator can generate the exponential pulse field at three meters away from the aperture plane of antenna with the rising time less than 5 ns,pulse width more than 300 ns and peak value of field strength greater than 50 kV/m.The developed fast rising pulse source basically satisfies the

  4. Photoionization of hydrogen atom by coherent intense high-frequency short laser pulses: Direct propagation of electron wave packets on enormous spatial grids

    CERN Document Server

    Demekhin, Philipp V; Cederbaum, Lorenz S

    2013-01-01

    The time-dependent Schr\\"{o}dinger equation for the hydrogen atom and its interaction with coherent intense high-frequency short laser pulses is solved numerically exactly by employing the code implemented for the multi-configurational time-dependent Hartree-Fock (MCTDHF) method. Thereby, the wavefunction is followed in space and time for times longer than the pulse duration. Results are explicitly shown for 3 and 10 fs pulses. Particular attention is paid to identifying the effect of dynamic interference of photoelectrons emitted with the same kinetic energy at different times during the rising and falling sides of the pulse predicted in [\\emph{Ph.V. Demekhin and L.S. Cederbaum}, Phys. Rev. Lett. \\textbf{108}, 253001 (2012)]. In order to be able to see the dynamic interference pattern in the computed electron spectra, the photoelectron wave packet has to be propagated over long distances. Clearly, complex absorption potentials often employed to compute spectra of emitted particles cannot be used to detect dy...

  5. Pulsed versus continuous wave low-level light therapy on osteoarticular signs and symptoms in limited scleroderma (CREST syndrome): a case report

    Science.gov (United States)

    Barolet, Daniel

    2014-11-01

    Limited cutaneous systemic sclerosis (lcSSc) was formerly known as CREST syndrome in reference to the associated clinical features: calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasias. The transforming growth factor beta has been identified as a major player in the pathogenic process, where low-level light therapy (LLLT) has been shown to modulate this cytokine superfamily. This case study was conducted to assess the efficacy of 940 nm using millisecond pulsing and continuous wave (CW) modes on osteoarticular signs and symptoms associated with lcSSc. The patient was treated two to three times a week for 13 weeks using a sequential pulsing mode on one elbow and a CW mode on the other. Efficacy assessments included inflammation, symptoms, pain, health scales, patient satisfaction, clinical global impression, and adverse effects monitoring. Considerable functional and morphologic improvements were observed after LLLT, with the best results seen with the pulsing mode. No adverse effects were noted. Pulsed LLLT represents a treatment alternative for osteoarticular signs and symptoms in limited scleroderma (CREST syndrome).

  6. Operation of Terahertz Quantum-cascade Lasers at 164 K in Pulsed Mode and at 117 K in Continuous-wave Mode

    Science.gov (United States)

    Williams, Benjamin S.; Kumar, Sushil; Hu, Qing; Reno, John L.

    2005-01-01

    We report the demonstration of a terahertz quantum-cascade laser that operates up to 164 K in pulsed mode and 117 K in continuous-wave mod e at approximately 3.0 THz. The active region was based on a resonant -phonon depopulation scheme and a metal-metal waveguide was used for modal confinement. Copper to copper thermocompression wafer bonding w as used to fabricate the waveguide, which displayed improved thermal properties compared to a previous indium-gold bonding method.

  7. Fabrication, optimization, and characterization of monolithic semiconductor mode-locked lasers and colliding, pulse mode-locked lasers at millimeter-wave frequencies

    Science.gov (United States)

    Passerini, Marco; Sorel, Marc; Laybourn, Peter J.; Giuliani, Guido; Donati, Silvano

    2004-09-01

    This work reports on the fabrication, optimisation and characterisation of monolithic mode-locked lasers (MLLs) and colliding-pulse mode-locked (CPM) lasers with repetition rate in the range 10-60 GHz. The devices consist of double section split-contact ridge waveguide lasers fabricated in GaAs/AlGaAs double quantum well (DQW) material. For CPM devices, the saturable absorber section was fabricated with a coplanar ground-signal-ground (G-S-G) pad structure. The optimum saturable absorber size for efficient mode-locking is found experimentally. The fabricated devices are characterised in terms of operating regimes (Continuous Wave, Self-Pulsation, Mode-Locking) and the mode-locking signals were observed in the frequency domain using an external fast photodiode. In the case of CPM devices a mm-wave signal could also be extracted directly from the saturable absorber section of the laser using a microwave probe.

  8. Pulse Onset Detection using Neighbor Pulse-Based Signal Enhancement

    OpenAIRE

    Xu, Peng; Bergsneider, Marvin; Hu, Xiao

    2008-01-01

    Detecting onsets of cardiovascular pulse wave signals is an important prerequisite for successfully conducting various analysis tasks involving the concept of pulse wave velocity. However, pulse onsets are frequently influenced by inherent noise and artifacts in signals continuously acquired in a clinical environment. The present work proposed and validated a neighbor pulse-based signal enhancement algorithm for reducing error in the detected pulse onset locations from noise-contaminated puls...

  9. High frame rate and high line density ultrasound imaging for local pulse wave velocity estimation using motion matching: A feasibility study on vessel phantoms.

    Science.gov (United States)

    Li, Fubing; He, Qiong; Huang, Chengwu; Liu, Ke; Shao, Jinhua; Luo, Jianwen

    2016-04-01

    Pulse wave imaging (PWI) is an ultrasound-based method to visualize the propagation of pulse wave and to quantitatively estimate regional pulse wave velocity (PWV) of the arteries within the imaging field of view (FOV). To guarantee the reliability of PWV measurement, high frame rate imaging is required, which can be achieved by reducing the line density of ultrasound imaging or transmitting plane wave at the expense of spatial resolution and/or signal-to-noise ratio (SNR). In this study, a composite, full-view imaging method using motion matching was proposed with both high temporal and spatial resolution. Ultrasound radiofrequency (RF) data of 4 sub-sectors, each with 34 beams, including a common beam, were acquired successively to achieve a frame rate of ∼507 Hz at an imaging depth of 35 mm. The acceleration profiles of the vessel wall estimated from the common beam were used to reconstruct the full-view (38-mm width, 128-beam) image sequence. The feasibility of mapping local PWV variation along the artery using PWI technique was preliminarily validated on both homogeneous and inhomogeneous polyvinyl alcohol (PVA) cryogel vessel phantoms. Regional PWVs for the three homogeneous phantoms measured by the proposed method were in accordance with the sparse imaging method (38-mm width, 32-beam) and plane wave imaging method. Local PWV was estimated using the above-mentioned three methods on 3 inhomogeneous phantoms, and good agreement was obtained in both the softer (1.91±0.24 m/s, 1.97±0.27 m/s and 1.78±0.28 m/s) and the stiffer region (4.17±0.46 m/s, 3.99±0.53 m/s and 4.27±0.49 m/s) of the phantoms. In addition to the improved spatial resolution, higher precision of local PWV estimation in low SNR circumstances was also obtained by the proposed method as compared with the sparse imaging method. The proposed method might be helpful in disease detections through mapping the local PWV of the vascular wall. PMID:26773791

  10. Consequences of the magnetic field, sonic and radiofrequency waves and intense pulsed light on the labeling of blood constituents with technetium-99m

    International Nuclear Information System (INIS)

    Sources of magnetic field, radiofrequency and audible sonic waves and pulsed light have been used in physiotherapy to treat different disorders. In nuclear medicine, blood constituents(Bl-Co) are labeled with technetium-99m (99mTc) are used. This study evaluated the consequences of magnetic field, radiofrequency and audible sonic waves and intense pulsed light sources on the labeling of Bl-Co with 99mTc. Blood from Wistar rats was exposed to the cited sources. The labeling of Bl-Co with 99mTc was performed. Blood not exposed to the physical agents was used(controls). Data showed that the exposure to the different studied sources did not alter significantly (p>0.05) the labeling of Bl-Co. Although the results were obtained with animals, the data suggest that no alteration on examinations performed with Bl-Co labeled with 99mTc after exposition to the cited agents. The biological consequences associated with these agents would be not capable to interfere with some properties of the Bl-Co. (author)

  11. Consequences of the magnetic field, sonic and radiofrequency waves and intense pulsed light on the labeling of blood constituents with technetium-99m

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Patricia Froes; Costa, Iris do Ceu Clara; Brandao-Neto, Jose; Medeiros, Aldo da Cunha [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-graduacao em Ciencias da Saude; Santos-Filho, Sebastiao David; Adenilson de Souza da Fonseca; Bernardo-Filho, Mario [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes. Lab. de Radiofarmacia Experimental; Ariel Ronzio, Oscar [Universidad de Buenos Aires (Argentina); Bonelli, Ludmila [Universidade Salgado de Oliveira, Belo Horizonte, MG (Brazil)

    2007-09-15

    Sources of magnetic field, radiofrequency and audible sonic waves and pulsed light have been used in physiotherapy to treat different disorders. In nuclear medicine, blood constituents(Bl-Co) are labeled with technetium-99m ({sup 99m}Tc) are used. This study evaluated the consequences of magnetic field, radiofrequency and audible sonic waves and intense pulsed light sources on the labeling of Bl-Co with {sup 99m}Tc. Blood from Wistar rats was exposed to the cited sources. The labeling of Bl-Co with {sup 99m}Tc was performed. Blood not exposed to the physical agents was used(controls). Data showed that the exposure to the different studied sources did not alter significantly (p>0.05) the labeling of Bl-Co. Although the results were obtained with animals, the data suggest that no alteration on examinations performed with Bl-Co labeled with {sup 99m}Tc after exposition to the cited agents. The biological consequences associated with these agents would be not capable to interfere with some properties of the Bl-Co. (author)

  12. Comparison of Thresholds for Pulmonary Capillary Hemorrhage Induced by Pulsed-wave and B-mode Ultrasound

    Science.gov (United States)

    Miller, Douglas L.; Dou, Chunyan; Raghavendran, Krishnan

    Pulsed ultrasound was found to induce pulmonary capillary hemorrhage (PCH) in mice about 25 years ago but remains a poorly understood risk factor for pulmonary diagnostic ultrasound. In early research using laboratory fixed beam ultrasound, thresholds for PCH had frequency variation from 1-4 MHz similar to the Mechanical Index. In recent research, thresholds for B mode diagnostic ultrasound from 1.5-12 MHz had little dependence on frequency. To compare the diagnostic ultrasound method to laboratory pulsed exposure, thresholds for fixed beam ultrasound were determined using comparable methods at 1.5 and 7.5 MHz. PCH thresholds were lower for simple fixed-beam pulse modes than for B mode and in approximate agreement with early research. However, for comparable timing parameters, PCH thresholds had little dependence on ultrasonic frequency. These findings suggest that the MI may not be directly useful as a dosimetric parameter for safety guidance in pulmonary ultrasound.

  13. Photoelectron circular dichroism in the multiphoton ionization by short laser pulses. I. Propagation of single-active-electron wave packets in chiral pseudo-potentials.

    Science.gov (United States)

    Artemyev, Anton N; Müller, Anne D; Hochstuhl, David; Demekhin, Philipp V

    2015-06-28

    A theoretical method to study the angle-resolved multiphoton ionization of polyatomic molecules is developed. It is based on the time-dependent formulation of the Single Center (TDSC) method and consists in the propagation of single-active-electron wave packets in the effective molecular potentials in the presence of intense laser pulses. For this purpose, the time-dependent Schrödinger equation for one electron, moving in a molecular field and interacting with an arbitrary laser pulse, is solved in spherical coordinates by an efficient numerical approach. As a test, the method is applied to the one- and two-photon ionizations of a model methane-like chiral system by circularly polarized short intense high-frequency laser pulses. Thereby, we analyze the photoelectron circular dichroism (PECD) in the momentum distribution. The considered model application illustrates the capability of the TDSC method to study multiphoton PECD in fixed-in-space and randomly oriented chiral molecules. PMID:26133408

  14. Arterial Stiffness, Central Pulsatile Hemodynamic Load, and Orthostatic Hypotension.

    Science.gov (United States)

    Liu, Kai; Wang, Si; Wan, Shixi; Zhou, Yufei; Pan, Pei; Wen, Bo; Zhang, Xin; Liao, Hang; Shi, Di; Shi, Rufeng; Chen, Xiaoping; Jangala, Tulasiram

    2016-07-01

    The association between central pulsatile hemodynamic load, arterial stiffness, and orthostatic hypotension (OH) is unclear. The authors recruited 1099 participants from the community. Questionnaire, physical examination, and laboratory tests were performed. To assess the correlation between central pulsatile hemodynamic load, arterial stiffness, and OH, multiple logistic regression analysis was performed, and the discriminatory power was assessed by the area under the receiver operating curve. The prevalence of OH in this population was 5.6%. After adjusting for potential confounders, brachial-ankle pulse wave velocity (BaPWV) was significantly and positively correlated with OH in both the hypertension and nonhypertension groups (all Ppower than CSBP in both subgroups. BaPWV appears to be a better indicator of OH than CSBP in routine clinical practice. PMID:26543017

  15. Serum ferritin levels are associated with arterial stiffness in healthy Korean adults.

    Science.gov (United States)

    Ha, Ji Yoon; Kim, Min Kyung; Kang, Shinae; Nam, Ji Sun; Ahn, Chul Woo; Kim, Kyung Rae; Park, Jong Suk

    2016-08-01

    Although an association between serum ferritin and atherosclerosis has been suggested, limited epidemiologic data are available regarding the association between ferritin and arterial stiffness in healthy adults. A total of 2932 healthy subjects were enrolled in this study. Anthropometric and biochemical profiles including ferritin were measured. The arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV). Serum ferritin levels were classified into quartiles and baPWV values gradually increased with each ferritin quartile. Multiple regression analysis showed that ferritin levels were independently correlated with baPWV. After adjusting for multiple risk factors, as compared with the lowest quartile, the odds ratios for high baPWV (>75(th) percentile) were 1.15 (0.84-1.56), 1.37 (0.97-1.73), and 1.46 (1.29-2.17) among men (p for trend Korean adults. PMID:26926288

  16. Development of a C-band 50 MW pulse klystron using traveling-wave-type output structure

    International Nuclear Information System (INIS)

    SuperKEKB requires a new klystron to increase its positron acceleration energy from 3.5 to 8.0 GeV. The C-Band 50 MW pulse Klystron (PV-5050K) has been under development at Mitsubishi Electric Corporation in collaboration with KEK for SuperKEKB. The first tube had been built and evaluated the performances, 50 MW output power and 48.5% power efficiency at pulse width of 2.0 μs and repetition rate of 50 pps. (author)

  17. Bright and peaklike pulse solitary waves and analogy with modulational instability in an extended nonlinear Schrödinger equation.

    Science.gov (United States)

    Kenmogne, Fabien; Yemélé, David

    2013-10-01

    The modulational instability (MI) phenomenon in the nonlinear Schrödinger equation (NLSE) extended by two different nonlinear dispersion terms and the gradient term is investigated. We find that the possibility of instability of plane waves depends on the sign of the nonlinear dispersion parameters with regard to the linear dispersion coefficient. In contrast to the basic NLSE, the system may exhibit instability in the defocusing media for amplitude exceeding a critical value depending on the magnitude of the nonlinear dispersion. An additional feature, namely the higher order or the infinite gain band, absent in the NLSE case, may appear and in which MI induces the birth of the nonlinear localized wave (NLW) of different carrier wave numbers. The result of the qualitative investigations of the system's dynamics indicates the existence of the NLW, such as peak, bright, dark, and compact dark solitary waves which can be well predicted by the MI criteria. In addition the nonlinear dispersion induces the existence of a pair of bright-dark solitary waves which is usually exhibited by the coupled NLSEs only, and the pairs of peak-dark and compact dark-bright solitary waves. PMID:24229297

  18. Time-resolved observation of coherent excitonic nonlinear response with a table-top narrowband THz pulse wave

    International Nuclear Information System (INIS)

    By combining a tilted-pulse-intensity-front scheme using a LiNbO3 crystal and a chirped-pulse-beating method, we generated a narrowband intense terahertz (THz) pulse, which had a maximum electric field of more than 10 kV/cm at around 2 THz, a bandwidth of ∼50 GHz, and frequency tunability from 0.5 to 2 THz. By performing THz-pump and near-infrared-probe experiments on GaAs quantum wells, we observed that the resonant excitation of the intraexcitonic 1s-2p transition induces a clear and large Autler-Townes splitting. Our time-resolved measurements show that the splitting energy observed in the rising edge region of electric field is larger than in the constant region. This result implies that the splitting energy depends on the time-averaged THz field over the excitonic dephasing time rather than that at the instant of the exciton creation by a probe pulse

  19. Time-resolved observation of coherent excitonic nonlinear response with a table-top narrowband THz pulse wave

    CERN Document Server

    Uchida, K; Aoki, T; Wolpert, C; Tamaya, T; Tanaka, K; Mochizuki, T; Kim, C; Yoshita, M; Akiyama, H; Pfeiffer, L N; West, K W

    2015-01-01

    By combining a tilted-pulse-intensity-front scheme using a LiNbO3 crystal and a chirped-pulse-beating method, we generated a narrowband intense terahertz (THz) pulse, which had a maximum electric field of more than 10 kV/cm at around 2 THz, a bandwidth of about 50 GHz,and frequency tunability from 0.5 to 2 THz. By performing THz-pump and near-infrared-probe experiments on GaAs quantum wells, we observed that the resonant excitation of the intraexcitonic 1s-2p transition induces a clear and large Autler-Townes splitting. Our time-resolved measurements show that the splitting energy observed in the rising edge region of electric field is larger than in the constant region. This result implies that the splitting energy depends on the time-averaged THz field over the excitonic dephasing time rather than that at the instant of the exciton creation by a probe pulse.

  20. Time-resolved observation of coherent excitonic nonlinear response with a table-top narrowband THz pulse wave

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, K. [Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Hirori, H., E-mail: hirori@icems.kyoto-u.ac.jp [Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Aoki, T. [CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Department of Applied Physics, School of Advanced Science and Technology, Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Wolpert, C.; Tamaya, T. [Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); Tanaka, K. [Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Mochizuki, T.; Kim, C.; Yoshita, M.; Akiyama, H. [Institute for Solid State Physics, University of Tokyo, and JST-CREST, Kashiwa, Chiba 277-8581 (Japan); Pfeiffer, L. N.; West, K. W. [Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    2015-11-30

    By combining a tilted-pulse-intensity-front scheme using a LiNbO{sub 3} crystal and a chirped-pulse-beating method, we generated a narrowband intense terahertz (THz) pulse, which had a maximum electric field of more than 10 kV/cm at around 2 THz, a bandwidth of ∼50 GHz, and frequency tunability from 0.5 to 2 THz. By performing THz-pump and near-infrared-probe experiments on GaAs quantum wells, we observed that the resonant excitation of the intraexcitonic 1s-2p transition induces a clear and large Autler-Townes splitting. Our time-resolved measurements show that the splitting energy observed in the rising edge region of electric field is larger than in the constant region. This result implies that the splitting energy depends on the time-averaged THz field over the excitonic dephasing time rather than that at the instant of the exciton creation by a probe pulse.

  1. Tunable error-free optical frequency conversion of a 4ps optical short pulse over 25 nm by four-wave mixing in a polarisation-maintaining optical fibre

    Science.gov (United States)

    Morioka, T.; Kawanishi, S.; Saruwatari, M.

    1994-05-01

    Error-free, tunable optical frequency conversion of a transform-limited 4.0 ps optical pulse signalis demonstrated at 6.3 Gbit/s using four-wave mixing in a polarization-maintaining optical fibre. The process generates 4.0-4.6 ps pulses over a 25nm range with time-bandwidth products of 0.31-0.43 and conversion power penalties of less than 1.5 dB.

  2. Usefulness of pulse-wave doppler tissue sampling and dobutamine stress echocardiography for identification of false positive inferior wall defects in SPECT

    International Nuclear Information System (INIS)

    False positive inferior wall perfusion defects restrict the accuracy of SPECT in diagnosis of coronary artery disease (CAD). Pulse-Wave Tissue Doppler (PWTD) has been recently proposed to assess regional wall motion velocities. The objectives of this study were to evaluate the presence of CAD by using PWTD during dobutamine stress echocardiography (DSE) in patients with an inferior perfusion defect detected by SPECT and compare PWTD parameters of normal cases with patients who had inferior perfusion defect and CAD. Sixty-five patients (mean age 58±8 years, 30 men) with a normal LV systolic function at rest according to echocardiographic evaluation with an inferior ischemia determined by SPECT and a control group (CG) of 34 normal cases (mean age 56±7 years, 16 men) were included in this study. All patients underwent a standard DSE (up to 40 μg/kg/min with additional atropine during sub-maximum heart rate responses). Pulse-wave Doppler tissue sampling of inferior wall was performed in the apical 2-chamber view at rest and stress. The coronary angiography was performed within 24 hours. The results were evaluated for the prediction of significant right coronary artery (RCA) and/or left circumflex coronary artery (CX) with narrowing (≥50% diameter stenosis, assessed by quantitative coronary angiography). It was observed that the peak stress mean E/A ratio was lower in patients with CAD when compared to patients without CAD (0.78±0.2 versus 1.29±0.11 p<0.0001). Also the peak stress E/A ratio of normal cases was significantly higher than patients who had CAD (1.19±0.3 versus 0.78±0.2 p<0.0001). When the cut off point for the E/A ratio was determined as 1, the sensitivity and specificity of dobutamine stress PWTD E/A were 89% and 86%, respectively. The peak stress E/A ratio was higher than 1 in all patients with a false positive perfusion defect. Systolic S velocity increase during DSE was significantly lower in patients with CAD (54%±17 versus 99%±24 p=0

  3. Permanent fixing or reversible trapping and release of DNA micropatterns on a gold nanostructure using continuous-wave or femtosecond-pulsed near-infrared laser light.

    Science.gov (United States)

    Shoji, Tatsuya; Saitoh, Junki; Kitamura, Noboru; Nagasawa, Fumika; Murakoshi, Kei; Yamauchi, Hiroaki; Ito, Syoji; Miyasaka, Hiroshi; Ishihara, Hajime; Tsuboi, Yasuyuki

    2013-05-01

    The use of localized surface plasmons (LSPs) for highly sensitive biosensors has already been investigated, and they are currently being applied for the optical manipulation of small nanoparticles. The objective of this work was the optical trapping of λ-DNA on a metallic nanostructure with femtosecond-pulsed (fs) laser irradiation. Continuous-wave laser irradiation, which is generally used for plasmon excitation, not only increased the electromagnetic field intensity but also generated heat around the nanostructure, causing the DNA to become permanently fixed on the plasmonic substrate. Using fs laser irradiation, on the other hand, the reversible trapping and release of the DNA was achieved by switching the fs laser irradiation on and off. This trap-and-release behavior was clearly observed using a fluorescence microscope. This technique can also be used to manipulate other biomolecules such as nucleic acids, proteins, and polysaccharides and will prove to be a useful tool in the fabrication of biosensors. PMID:23586869

  4. Investigation of continuous wave and pulsed laser performance based on Nd3+:Gd0.6Y1.4SiO5 crystal

    Science.gov (United States)

    Feng, Chao; Liu, Zhaojun; Cong, Zhenhua; Shen, Hongbin; Li, Yongfu; Wang, Qingpu; Fang, Jiaxiong; Xu, Xiaodong; Xu, Jun; Zhang, Xingyu

    2015-12-01

    We systematically investigated a laser diode (LD) pumped Nd:GYSO (Nd3+:Gd0.6Y1.4SiO5) laser. The output power of the continuous wave laser was as high as 3.5 W with a slope efficiency of 31.8%. In the Q-switched operation; the laser exhibited dual-wavelengths output (1073.6 nm and 1074.7 nm) synchronously with a Cr4+:YAG as the saturable absorber (SA). Additionally, a passively mode-locked laser was demonstrated using a semiconductor SA mirror with a maximum average output power of 510 mW at a central wavelength of 1074 nm, while the pulse width of the laser was as short as 5 ps. Our experiment proved that the Nd:GYSO mixed crystal was a promising material for a solid-state laser.

  5. All-fiber quasi-continuous wave supercontinuum generation in single-mode high-nonlinear fiber pumped by submicrosecond pulse with low peak power.

    Science.gov (United States)

    Gao, Weiqing; Liao, Meisong; Yan, Xin; Suzuki, Takenobu; Ohishi, Yasutake

    2012-05-01

    We demonstrate quasi-continuous wave supercontinuum generation in a single-mode high-nonlinear fiber (HNLF) in 1.55 μm band, which is pumped by the amplified passively Q-switched submicrosecond pulse. The pump wavelength is in the normal dispersion region of HNLF and near to the zero-dispersion wavelength. The broad SC spectral range from 1200 to 2260 nm is obtained with the low pump peak power of 17.8 W. The 20 dB bandwidth of 922 nm from 1285 to 2207 nm is obtained with the assumption that the peak near 1560 nm is filtered. The spectrum density for the 20 dB bandwidth is from -27.5 to -7.5 dbm/nm. PMID:22614410

  6. Thermal decomposition of 1-chloropropane behind the reflected shock waves in the temperature range of 1015-1220 K: Single pulse shock tube and computational studies

    Indian Academy of Sciences (India)

    G Sudhakar; B Rajakumar

    2014-07-01

    The thermal decomposition of 1-chloropropane in argon was studied behind reflected shock waves in a single pulse shock tube over the temperature range of 1015-1220 K. The reaction mainly goes through unimolecular elimination of HCl. The major products observed in the decomposition are propylene and ethylene, while the minor products identified are methane and propane. The rate constant for HCl elimination in the studied temperature range is estimated to be k(1015-1220 K) = 1.63 × 1013exp(-(60.1 ± 1.0) kcal mol-1/RT) s-1. The DFT calculations were carried out to identify the transition state(s) for the major reaction channel; and rate coefficient for this reaction is obtained to be k(800-1500 K) = 5.01 × 1014exp(-(58.8) kcal mol-1/RT) s-1. The results are compared with the experimental findings.

  7. Assessment of pulse rate variability by the method of pulse frequency demodulation

    OpenAIRE

    Ohte Nobuyuki; Kamiya Atsunori; Barros Allan; Hayano Junichiro; Yasuma Fumihiko

    2005-01-01

    Abstract Background Due to its easy applicability, pulse wave has been proposed as a surrogate of electrocardiogram (ECG) for the analysis of heart rate variability (HRV). However, its smoother waveform precludes accurate measurement of pulse-to-pulse interval by fiducial-point algorithms. Here we report a pulse frequency demodulation (PFDM) technique as a method for extracting instantaneous pulse rate function directly from pulse wave signal and its usefulness for assessing pulse rate variab...

  8. Ethnic Differences in and Childhood Influences on Early Adult Pulse Wave Velocity: The Determinants of Adolescent, Now Young Adult, Social Wellbeing, and Health Longitudinal Study.

    Science.gov (United States)

    Cruickshank, J Kennedy; Silva, Maria J; Molaodi, Oarabile R; Enayat, Zinat E; Cassidy, Aidan; Karamanos, Alexis; Read, Ursula M; Faconti, Luca; Dall, Philippa; Stansfield, Ben; Harding, Seeromanie

    2016-06-01

    Early determinants of aortic stiffness as pulse wave velocity are poorly understood. We tested how factors measured twice previously in childhood in a multiethnic cohort study, particularly body mass, blood pressure, and objectively assessed physical activity affected aortic stiffness in young adults. Of 6643 London children, aged 11 to 13 years, from 51 schools in samples stratified by 6 ethnic groups with different cardiovascular risk, 4785 (72%) were seen again at aged 14 to 16 years. In 2013, 666 (97% of invited) took part in a young adult (21-23 years) pilot follow-up. With psychosocial and anthropometric measures, aortic stiffness and blood pressure were recorded via an upper arm calibrated Arteriograph device. In a subsample (n=334), physical activity was measured >5 days via the ActivPal. Unadjusted pulse wave velocities in black Caribbean and white UK young men were similar (mean±SD 7.9±0.3 versus 7.6±0.4 m/s) and lower in other groups at similar systolic pressures (120 mm Hg) and body mass (24.6 kg/m(2)). In fully adjusted regression models, independent of pressure effects, black Caribbean (higher body mass/waists), black African, and Indian young women had lower stiffness (by 0.5-0.8; 95% confidence interval, 0.1-1.1 m/s) than did white British women (6.9±0.2 m/s). Values were separately increased by age, pressure, powerful impacts from waist/height, time spent sedentary, and a reported racism effect (+0.3 m/s). Time walking at >100 steps/min was associated with reduced stiffness (Pracism) independently increase arterial stiffness, effects likely to increase with age. PMID:27141061

  9. THE DIAGNOSTIC VALUE OF PULSED WAVE TISSUE DOPPLER IMAGING IN ASYMPTOMATIC BETA- THALASSEMIA MAJOR CHILDREN AND YOUNG ADULTS ; RELATION TO CHEMICAL BIOMARKERS OF LEFT VENTRICULAR FUNCTION AND IRON OVERLOAD .

    Directory of Open Access Journals (Sweden)

    Seham Ragab

    2015-08-01

    Full Text Available Background: Cardiac iron toxicity is the leading cause of death among  β-halassaemia major (TM  patients.  Once  heart failure becomes overt , it will be  difficult to reverse . Objectives: To investigate non overt cardiac dysfunctions  in TM patients using  pulsed wave Tissue Doppler  Imaging (TD I and its relation to the iron overload and brain natruritic peptide (BNP. Methods: Thorough  clinical , conventional echo and  pulsed  wave TDI  parameters were compared between  asymtomatic 25 β-TM  patients  and 20 age and gender matched individuals. Serum ferritin and plasma BNP  levels were assayed by  ELISA .  Results: TM patients had significant higher mitral inflow early diastolic (E wave and  non significant other conventional echo  parameters. Pulsed wave TDI revealed systolic and diastolic dysfunctions in the form of significant higher  isovolumetric contraction time (ICT , ejection time ( E T and  isovolumetric relaxation time (IRT with significantly lower  mitral annulus  early diastolic velocity E` (12.07 ±2.06 vs 15.04±2.65 ,P= 0.003  in patients compared to  controls. Plasma BNP was higher in patients compared to the controls.  Plasma BNP and serum ferritin had significant correlation with each other and with pulsed wave conventional and TDI indices of systolic and diastolic functions.  Patients with E/E` ≥ 8 had  significant higher  serum ferritin  and plasma BNP levels compared to those with E/E` ratio < 8 without difference in Hb levels .Conclusion:  Pulsed wave TDI  is an  important diagnostic tool for latent cardiac dysfunction in iron loaded TM patients and is related to iron overload and BNP .

  10. Regional in vivo transit time measurements of aortic pulse wave velocity in mice with high-field CMR at 17.6 Tesla

    Directory of Open Access Journals (Sweden)

    Rommel Eberhard

    2010-12-01

    Full Text Available Abstract Background Transgenic mouse models are increasingly used to study the pathophysiology of human cardiovascular diseases. The aortic pulse wave velocity (PWV is an indirect measure for vascular stiffness and a marker for cardiovascular risk. Results This study presents a cardiovascular magnetic resonance (CMR transit time (TT method that allows the determination of the PWV in the descending murine aorta by analyzing blood flow waveforms. Systolic flow pulses were recorded with a temporal resolution of 1 ms applying phase velocity encoding. In a first step, the CMR method was validated by pressure waveform measurements on a pulsatile elastic vessel phantom. In a second step, the CMR method was applied to measure PWVs in a group of five eight-month-old apolipoprotein E deficient (ApoE(-/- mice and an age matched group of four C57Bl/6J mice. The ApoE(-/- group had a higher mean PWV (PWV = 3.0 ± 0.6 m/s than the C57Bl/6J group (PWV = 2.4 ± 0.4 m/s. The difference was statistically significant (p = 0.014. Conclusions The findings of this study demonstrate that high field CMR is applicable to non-invasively determine and distinguish PWVs in the arterial system of healthy and diseased groups of mice.

  11. High harmonic generation in H$_{2}^{+}$ and HD+ by intense femtosecond laser pulses: A wave packet approach with nonadiabatic interaction in HD+

    Indian Academy of Sciences (India)

    Farzana Sharmin; Samir Saha; S S Bhattacharyya

    2013-06-01

    We have theoretically investigated the high harmonic generation (HHG) spectra of H$_{2}^{+}$ and HD+ using a time-dependent wave packet approach for the nuclear motion with pulsed lasers of peak intensities (0) of 3.5 × 1014 and 4.5 × 1014 W/cm2, wavelengths (L) of 800 and 1064 nm, and pulse durations () of 40 and 50 fs, for initial vibrational levels 0 = 0 and 1. We have argued that for these conditions the harmonic generation due to the transitions in the electronic continuum by tunnelling or multiphoton ionization will not be important. Thus, the characteristic features of HHG spectra in our model arise only due to the nuclear motions on the two lowest field-coupled electronic states between which both interelectronic and intraelectronic (due to intrinsic dipole moments, for HD+) radiative transitions can take place. For HD+, the effect of nonadiabatic (NA) interaction between the two lowest Born–Oppenheimer (BO) electronic states has been taken into account and comparison has been made with the HHG spectra of HD+ obtained in the BO approximation. Even harmonics and a second plateau in the HHG spectra of HD+ with the NA interaction and hyper-Raman lines in the spectra of both H$_{2}^{+}$ and HD+ for 0 = 1 have been observed for higher value of 0 or L. Our calculations indicate reasonable efficiencies of harmonic generation even without involving the electronic continuum.

  12. Wave-packet dynamics in alkaline dimers. Investigation and control through coherent excitation with fs-pulses

    International Nuclear Information System (INIS)

    During my PhD thesis I investigated alkaline dimers with coherent control in a molecular beam as well as with pump-probe spectroscopy in a magneto-optical trap (MOT). The aim of the coherent control experiments were the isotope selective ionization with phase- and amplitude-shaped fs-pulses. Chapter 4 described the gained results of isotope selective ionization of NaK and KRb in a molecular beam by using different pulse formers. For the NaK dimer was the reached optimization factor RPh and Ampl770=Rmax/Rmin=25 between maximization and minimization of the isotopomer ratio (23Na39K)+/(23Na41K)+ with phase and amplitude modulation of the fs-pulse with a central wavelength of λ=770 nm. From the electronic ground-state X(1)1Σ+;ν''=0 transfers a one-photon-excitation population in the first excited A(2) 1Σ+ state. The coherent control experiment on KRb was used to maximize and minimize the isotopomer ratio (124KRb)+/(126KRb)+. It was the first coherent control experiment with a spectral resolution of 1.84 cm-1/Pixel. For the phase and amplitude optimization was the received optimization factor between minimization and maximization of the isotopomer ratio RPh and Ampl=Rmax/Rmin=7 at a central wavelength of 840 nm. The results showed a stepwise excitation process from the electronic ground-state in the first excited (2)1Σ+ state with a further excitation, that is possible over three resonant energy potential curves into the ionic ground-state. In the second part of my thesis I realized pump-probe spectroscopy of Rb2 dimers in a dark SPOT. (orig.)

  13. Rigorous 2D Model for Study of Pulsed and Monochromatic Waves Propagation Near the Earth’s Surface

    OpenAIRE

    Sautbekov, Seil S.; Yuriy K. Sirenko; Nataliya P. Yashina; Aleksey A. Vertiy

    2014-01-01

    A model problem considered in the paper allows solving rather complex 2D problems of the electromagnetic wave propagation with a required accuracy using conventional personal computers. The problems are of great importance for the theory and practical applications. The association of FDTD schemes with exact absorbing conditions makes up the basis for constructing models of the kind. This approach reduces the original open initial boundary value problems to the equivalent closed problems which...

  14. AB067. Future ED therapy: low-energy shock wave therapy and low-intensity pulsed ultrasound therapy

    OpenAIRE

    Xin, Zhong-Cheng

    2015-01-01

    Current treatments for erectile dysfunction (ED) such as phosphodiesterase type 5 inhibitors (PDE5Is) and intracavernosal injections (ICI) therapy, such a symptom therapy used as on demanded before sexual intercourse, the clinical efficacy reached to 80%, with mild side effects, however, such a symptom therapy could not restore pathological changes in the penis. Low-energy shock wave therapy (LESWT) has been developed for treating ED, and clinical studies have shown that LESWT has the potenti...

  15. Generation of shock waves and formation of craters in a solid material irradiated by a short laser pulse

    Czech Academy of Sciences Publication Activity Database

    Gus'kov, S. Yu.; Borodziuk, S.; Kálal, M.; Kasperczuk, A.; Králiková, Božena; Krouský, Eduard; Limpouch, J.; Mašek, Karel; Pisarczyk, T.; Pisarczyk, P.; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Ullschmied, Jiří

    2004-01-01

    Roč. 34, č. 11 (2004), s. 989-1003. ISSN 1063-7818 Grant ostatní: RFFI(RU) 02-02-16966; INTAS(XX) 01-0572; PALS project 3(XX) HPRI-CT-1999-00053 Institutional research plan: CEZ:AV0Z1010921 Keywords : laser radiation- matter interaction * shock waves * laser plasma Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.811, year: 2004

  16. Electrical stimulation vs. pulsed and continuous-wave optical stimulation of the rat prostate cavernous nerves, in vivo

    Science.gov (United States)

    Perkins, William C.; Lagoda, Gwen A.; Burnett, Arthur; Fried, Nathaniel M.

    2015-07-01

    Identification and preservation of the cavernous nerves (CNs) during prostate cancer surgery is critical for post-operative sexual function. Electrical nerve stimulation (ENS) mapping has previously been tested as an intraoperative tool for CN identification, but was found to be unreliable. ENS is limited by the need for electrode-tissue contact, poor spatial precision from electrical current spreading, and stimulation artifacts interfering with detection. Alternatively, optical nerve stimulation (ONS) provides noncontact stimulation, improved spatial selectivity, and elimination of stimulation artifacts. This study compares ENS to pulsed/CW ONS to explore the ONS mechanism. A total of eighty stimulations were performed in 5 rats, in vivo. ENS (4 V, 5 ms, 10 Hz) was compared to ONS using a pulsed diode laser nerve stimulator (1873 nm, 5 ms, 10 Hz) or CW diode laser nerve stimulator (1455 nm). Intracavernous pressure (ICP) response and nerve compound action potentials (nCAPs) were measured. All three stimulation modes (ENS, ONS-CW, ONS-P) produced comparable ICP magnitudes. However, ENS demonstrated more rapid ICP response times and well defined nCAPs compared to unmeasurable nCAPs for ONS. Further experiments measuring single action potentials during ENS and ONS are warranted to further understand differences in the ENS and ONS mechanisms.

  17. Pulsed High-Energy Radiographic Machine Emiting X-Rays (PHERMEX): applications to study high-pressure flow and detonation waves

    International Nuclear Information System (INIS)

    PHERMEX, an acronym for Pulsed High-Energy Radiographic Machine Emitting X-Rays, has been used as a diagnostic tool to make quantitative measurements from radiographs of inert materials under dynamic high-pressure conditions and of explosives during the detonation process. In some experiments, radiography is the best method (compared to high-speed optical cameras and contactor pins) to study complicated hydro-dynamic flow occuring in a dynamic experiment. To demonstrate the versatility and uniqueness of PHERMEX and the radiographic method, several experiments on inert solids having high and low atomic numbers will be discussed with some particulars. This includes the observation of the 11.0-GPa-pressure phase transition for antimony and the accompanying two-shock structure and the off-Hugoniot data for lead using regular reflection. Also, by careful design of a radiographic experiment, the Hugoniot state behind a shock front can be completely and precisely specified. Aluminium is an example of a material studies in this manner. PHERMEX is useful in studying some detonation properties of explosives. As an illustration, the discussion will include radiographic results of divergence characteristics of a detonation wave in sensitive explosives as it propagates past a corner and the effect of preshocking on the detonation process of insensitive explosives when the detonation wave interacts with a region that has been shock-compressed at a pressure too low to cause detonation

  18. ELF wave generation in the ionosphere using pulse modulated HF heating: initial tests of a technique for increasing ELF wave generation efficiency

    Directory of Open Access Journals (Sweden)

    R. Barr

    Full Text Available This paper describes the results of a preliminary study to determine the effective heating and cooling time constants of ionospheric currents in a simulated modulated HF heating, `beam painting' configuration. It has been found that even and odd harmonics of the fundamental ELF wave used to amplitude modulate the HF heater are sourced from different regions of the ionosphere which support significantly different heating and cooling time constants. The fundamental frequency and its odd harmonics are sourced in a region of the ionosphere where the heating and cooling time constants are about equal. The even harmonics on the other hand are sourced from regions of the ionosphere characterised by ratios of cooling to heating time constant greater than ten. It is thought that the even harmonics are sourced in the lower ionosphere (around 65 km where the currents are much smaller than at the higher altitudes around 78 km where the currents at the fundamental frequency and odd harmonics maximise.

    Key words. Electromagnetics (antennae · Ionosphere (active experiments · Radio science (non linear phenomena

  19. Rigorous 2D Model for Study of Pulsed and Monochromatic Waves Propagation Near the Earth’s Surface

    Directory of Open Access Journals (Sweden)

    Seil S. Sautbekov

    2014-01-01

    Full Text Available A model problem considered in the paper allows solving rather complex 2D problems of the electromagnetic wave propagation with a required accuracy using conventional personal computers. The problems are of great importance for the theory and practical applications. The association of FDTD schemes with exact absorbing conditions makes up the basis for constructing models of the kind. This approach reduces the original open initial boundary value problems to the equivalent closed problems which can be solved numerically using the standard grid methods.

  20. Energy of a shock wave generated in different metals under irradiation by a high-power laser pulse

    Czech Academy of Sciences Publication Activity Database

    Gus'kov, S. Yu.; Kasperczuk, A.; Pisarczyk, T.; Borodziuk, S.; Ullschmied, Jiří; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Skála, Jiří; Pisarczyk, P.

    2007-01-01

    Roč. 105, č. 4 (2007), s. 793-802. ISSN 1063-7761 R&D Projects: GA MŠk(CZ) LC528 Grant ostatní: HPC Europa(XE) RII3-CT-2003-506350 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z10100523 Source of funding: R - rámcový projekt EK Keywords : shock waves * laser radiation * laser plasma * inertial confinement * PALS laser Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.075, year: 2007

  1. Time-dependent wave packet approach to the pulse delay effect upon RbI photoelectron spectrum

    Institute of Scientific and Technical Information of China (English)

    LIU Chunhua; MENG Qingtian; ZHANG Qinggang

    2006-01-01

    The time-resolved photoelectron spectrum (TRPES) of Rbl molecule is simulated using the time-dependent wave-packet method. Both the normal three-photon ionization process and auto-ionization process are involved in the simulation. The calculated results show that the change of delay time will influence the shape of the photoelectron spectrum (PES), and the influence is substantially due to the existence of the crossing between excited states and the strong laser field which will change the position of relevant curves.

  2. Impaired Organization of Paired-Pulse TMS-Induced I-Waves After Human Spinal Cord Injury.

    Science.gov (United States)

    Cirillo, John; Calabro, Finnegan J; Perez, Monica A

    2016-05-01

    Paired-pulse transcranial magnetic stimulation (TMS) of the human motor cortex results in consecutive facilitatory motor-evoked potential (MEP) peaks in surface electromyography in intact humans. Here, we tested the effect of an incomplete cervical spinal cord injury (SCI) on early (first) and late (second and third) MEP peaks in a resting intrinsic finger muscle. We found that all peaks had decreased amplitude in SCI subjects compared with controls. The second and third peaks were delayed with the third peak also showing an increased duration. The delay of the third peak was smaller than that seen in controls at lower stimulation intensity, suggesting lesser influence of decreased corticospinal inputs. A mathematical model showed that after SCI the third peak aberrantly contributed to spinal motoneurone recruitment, regardless on the motor unit threshold tested. Temporal and spatial aspects of the late peaks correlated with MEP size and hand motor output. Thus, early and late TMS-induced MEP peaks undergo distinct modulation after SCI, with the third peak likely reflecting a decreased ability to summate descending volleys at the spinal level. We argue that the later corticospinal inputs on the spinal cord might be crucial for recruitment of motoneurones after human SCI. PMID:25814508

  3. Bramwell-Hill modeling for local aortic pulse wave velocity estimation: a validation study with velocity-encoded cardiovascular magnetic resonance and invasive pressure assessment

    Directory of Open Access Journals (Sweden)

    Westenberg Jos JM

    2012-01-01

    Full Text Available Abstract Background The Bramwell-Hill model describes the relation between vascular wall stiffness expressed in aortic distensibility and the pulse wave velocity (PWV, which is the propagation speed of the systolic pressure wave through the aorta. The main objective of this study was to test the validity of this model locally in the aorta by using PWV-assessments based on in-plane velocity-encoded cardiovascular magnetic resonance (CMR, with invasive pressure measurements serving as the gold standard. Methods Seventeen patients (14 male, 3 female, mean age ± standard deviation = 57 ± 9 years awaiting cardiac catheterization were prospectively included. During catheterization, intra-arterial pressure measurements were obtained in the aorta at multiple locations 5.8 cm apart. PWV was determined regionally over the aortic arch and locally in the proximal descending aorta. Subsequently, patients underwent a CMR examination to measure aortic PWV and aortic distention. Distensibility was determined locally from the aortic distension at the proximal descending aorta and the pulse pressure measured invasively during catheterization and non-invasively from brachial cuff-assessment. PWV was determined regionally in the aortic arch using through-plane and in-plane velocity-encoded CMR, and locally at the proximal descending aorta using in-plane velocity-encoded CMR. Validity of the Bramwell-Hill model was tested by evaluating associations between distensibility and PWV. Also, theoretical PWV was calculated from distensibility measurements and compared with pressure-assessed PWV. Results In-plane velocity-encoded CMR provides stronger correlation (p = 0.02 between CMR and pressure-assessed PWV than through-plane velocity-encoded CMR (r = 0.69 versus r = 0.26, with a non-significant mean error of 0.2 ± 1.6 m/s for in-plane versus a significant (p = 0.006 error of 1.3 ± 1.7 m/s for through-plane velocity-encoded CMR. The Bramwell-Hill model shows a

  4. Nonlinear pulse compression

    OpenAIRE

    Grün, Alexander

    2014-01-01

    In this thesis I investigate two methods for generating ultrashort laser pulses in spectral regions which are ordinarily difficult to achieve by the existing techniques. These pulses are specially attractive in the study of ultrafast (few femtosecond) atomic and molecular dynamics. The first involves Optical Parametric Amplification (OPA) mediated by four-wave-mixing in gas and supports the generation of ultrashort pulses in the Near-InfraRed (NIR) to the Mid-InfraRed (MIR) spectral regio...

  5. Modelling of the positive column of a medium-pressure Cs-Xe dc discharge affected by a millimetre wave pulse

    Science.gov (United States)

    Gitlin, M. S.; Epstein, I. L.; Lebedev, Yu A.

    2013-10-01

    A time-dependent zero-dimensional kinetic model of the positive column (PC) of a medium-pressure Cs-Xe dc discharge was used to gain a better insight into the physical basics of plasma techniques for imaging and control of millimetre wave (MMW) beams. The model allowed one to study the effect of MMWs on the kinetic and electrical characteristics of the spatially homogeneous PC of a Cs-Xe dc discharge. We computed the PC plasma parameters for 30 Torr and 45 Torr xenon and discharge current densities of about 0.1 A cm-2. First, the dependences of the PC parameters on caesium density were calculated in the case of no MMWs incident on the PC plasma. Then, the temporal evolution of the parameters of the PC plasma affected by a long watt-scale Ka-band MMW pulse was modelled for caesium densities of about 3 × 1012 and 5 × 1012 cm-3. The calculations showed that the electron temperature in the PC plasma attained quasisteady-state values for about 1 µs after the beginning of the MMW pulse. The electron temperature rises by 0.2-0.3 eV as the MMW intensity increases from 0 to 1 W cm-2. The rise time of the electron density decreased with an increase in the MMW intensity W from about 1 ms for W = 0.15 W cm-2 to tens of microseconds for W > 1.5 W cm-2. The steady-state values of the electron density increased in proportion to W, if W 3 W cm-2 could be a cause of the microwave breakdown of the homogeneous PC plasma. The results of the modelling are in good agreement with the published experimental data.

  6. Photoelectrocatalytic decomposition of ethylene using TiO2/activated carbon fiber electrode with applied pulsed direct current square-wave potential

    International Nuclear Information System (INIS)

    Highlights: • Ethylene was decomposed by a photoelectrocatalytic (PEC) process. • A pulsed direct current square-wave (PDCSW) potential was applied to the PEC cell. • An electrode of TiO2 or modified TiO2 and activated carbon fiber (ACF) was used. • TiO2/ACF photocatalyst electrodes were modified by gamma radiolysis. • Efficiencies of the PEC process were higher than those of the process using DC. - Abstract: Removing ethylene (C2H4) from the atmosphere of storage facilities for fruits and vegetable is one of the main challenges in their postharvest handling for maximizing their freshness, quality, and shelf life. In this study, we investigated the photoelectrocatalytic (PEC) degradation of ethylene gas by applying a pulsed direct current DC square-wave (PDCSW) potential and by using a Nafion-based PEC cell. The cell utilized a titanium dioxide (TiO2) photocatalyst or γ-irradiated TiO2 (TiO2*) loaded on activated carbon fiber (ACF) as a photoelectrode. The apparent rate constant of a pseudo-first-order reaction (K) was used to describe the PEC degradation of ethylene. Parameters of the potential applied to the PEC cell in a reactor that affect the degradation efficiency in terms of the K value were studied. These parameters were frequency, duty cycle, and voltage. Ethylene degradation by application of a constant PDCSW potential to the PEC electrode of either TiO2/ACF cell or TiO2*/ACF cell enhanced the efficiency of photocatalytic degradation and PEC degradation. Gamma irradiation of TiO2 in the electrode and the applied PDCSW potential synergistically increased the K value. Independent variables (frequency, duty cycle, and voltage) of the PEC cell fabricated from TiO2 subjected 20 kGy γ radiation were optimized to maximize the K value by using response surface methodology with quadratic rotation–orthogonal composite experimental design. Optimized conditions were as follows: 358.36 Hz frequency, 55.79% duty cycle, and 64.65 V voltage. The maximum K

  7. Real-time arrhythmia detection with supplementary ECG quality and pulse wave monitoring for the reduction of false alarms in ICUs.

    Science.gov (United States)

    Krasteva, Vessela; Jekova, Irena; Leber, Remo; Schmid, Ramun; Abächerli, Roger

    2016-08-01

    False intensive care unit (ICU) alarms induce stress in both patients and clinical staff and decrease the quality of care, thus significantly increasing both the hospital recovery time and rehospitalization rates. In the PhysioNet/CinC Challenge 2015 for reducing false arrhythmia alarms in ICU bedside monitor data, this paper validates the application of a real-time arrhythmia detection library (ADLib, Schiller AG) for the robust detection of five types of life-threatening arrhythmia alarms. The strength of the application is to give immediate feedback on the arrhythmia event within a scan interval of 3 s-7.5 s, and to increase the noise immunity of electrocardiogram (ECG) arrhythmia analysis by fusing its decision with supplementary ECG quality interpretation and real-time pulse wave monitoring (quality and hemodynamics) using arterial blood pressure or photoplethysmographic signals. We achieved the third-ranked real-time score (79.41) in the challenge (Event 1), however, the rank was not officially recognized due to the 'closed-source' entry. This study shows the optimization of the alarm decision module, using tunable parameters such as the scan interval, lead quality threshold, and pulse wave features, with a follow-up improvement of the real-time score (80.07). The performance (true positive rate, true negative rate) is reported in the blinded challenge test set for different arrhythmias: asystole (83%, 96%), extreme bradycardia (100%, 90%), extreme tachycardia (98%, 80%), ventricular tachycardia (84%, 82%), and ventricular fibrillation (78%, 84%). Another part of this study considers the validation of ADLib with four reference ECG databases (AHA, EDB, SVDB, MIT-BIH) according to the international recommendations for performance reports in ECG monitors (ANSI/AAMI EC57). The sensitivity (Se) and positive predictivity (+P) are: QRS detector QRS (Se, +P)  >  99.7%, ventricular ectopic beat (VEB) classifier VEB (Se, +P)  =  95%, and ventricular

  8. Consequences of the magnetic field, sonic and radiofrequency waves and intense pulsed light on the labeling of blood constituents with technetium-99m

    Directory of Open Access Journals (Sweden)

    Patricia Froes Meyer

    2007-09-01

    Full Text Available Sources of magnetic field, radiofrequency and audible sonic waves and pulsed light have been used in physiotherapy to treat different disorders. In nuclear medicine, blood constituents(Bl-Co are labeled with technetium-99m (99mTc are used. This study evaluated the consequences of magnetic field, radiofrequency and audible sonic waves and intense pulsed light sources on the labeling of Bl-Co with 99mTc. Blood from Wistar rats was exposed to the cited sources. The labeling of Bl-Co with 99mTc was performed. Blood not exposed to the physical agents was used(controls. Data showed that the exposure to the different studied sources did not alter significantly (p>0.05 the labeling of Bl-Co. Although the results were obtained with animals, the data suggest that no alteration on examinations performed with Bl-Co labeled with 99mTc after exposition to the cited agents. The biological consequences associated with these agents would be not capable to interfere with some properties of the Bl-Co.Fontes de campo magnético, ondas sonoras audíveis e de radiofreqüência e luz intensa pulsada são usadas para o tratamento de doenças. Constituintes sangüíneos(CS marcados com tecnécio-99m(99mTc são utilizados na medicina nuclear. Esse trabalho avaliou as consequências de fontes de campo magnético, ondas sonoras audíveis e de radiofreqüência e luz intensa pulsada na marcação de CS com 99mTc. Sangue de ratos Wistar foi exposto às fontes citadas. A marcação de CS com 99mTc foi realizada. Sangue não exposto foram utilizadas(controle. Resultados mostraram que os agentes físicos estudados não alteraram significativamente (p>0.05 a radiomarcação de CS. Apesar terem sido obtidos com sangue de animais, os resultados sugerem que nenhuma alteração nos exames realizados com constituintes sangüíneos com 99mTc em medicina nuclear ocorreria após a exposição às fontes avaliadas. As consequências biológicas associadas a esses agentes não seriam

  9. Interferometry in pulsed fields

    OpenAIRE

    Döbrich, Babette; Gies, Holger

    2009-01-01

    We discuss the particle-physics discovery potential of ground-based gravitational-wave interferometers. With the use of pulsed magnetic fields, current and future gravitational-wave interferometers could not only be utilized to observe phenomena of strong-field QED, but they could also be applied to sweep the parameter space of particles of the hidden sector.

  10. The Detection and Exclusion of the Prostate Neuro-Vascular Bundle (NVB) in Automated HIFU Treatment Planning Using a Pulsed-Wave Doppler Ultrasound System

    Science.gov (United States)

    Chen, Wohsing; Carlson, Roy F.; Fedewa, Russell; Seip, Ralf; Sanghvi, Narendra T.; Dines, Kris A.; Pfile, Richard; Penna, Michael A.; Gardner, Thomas A.

    2005-03-01

    Men with prostate cancer are likely to develop impotence after prostate cancer therapy if the treatment damages the neuro-vascular bundles (NVB). The NVB are generally located at the periphery of the prostate gland. To preserve the NVB, a Doppler system is used to detect and localize the associated blood vessels. This information is used during the therapy planning procedure to avoid treatment surrounding the blood vessel areas. The Sonablate®500 (Focus Surgery, Inc.) image-guided HIFU device is enhanced with a pulse-wave multi-gate Doppler system that uses the current imaging transducer and mechanical scanner to acquire Doppler data. Doppler detection is executed after the regular B-mode images are acquired from the base to the apex of the prostate using parallel sector scans. The results are stored and rendered in 3-D display, registered with additional models generated for the capsule, urethra, and rectal wall, and the B-mode data and treatment plan itself. The display of the blood flow can be in 2-D color overlaid on the B-mode image or in 3-D color structure. Based on this 3-D model, the HIFU treatment planning can be executed in automated or manual mode by the physician to remove originally defined treatment zones that overlap with the NVB (for preservation of NVB). The results of the NVB detection in animal experiments, and the 3-D modeling and data registration of the prostate will be presented.

  11. Pulse-Wave Analysis of Optic Nerve Head Circulation Is Significantly Correlated with Kidney Function in Patients with and without Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Tomoaki Shiba

    2014-01-01

    Full Text Available Aim. To determine whether there is a significant correlation between the optic nerve head (ONH circulation determined by laser speckle flowgraphy (LSFG and kidney function. Materials. Seventy-one subjects were investigated. The estimated glomerular filtration rate (GFR and serum creatinine, cystatin C, and urinary albumin excretion were measured. The ONH circulation was determined by an analysis of the pulse wave of LSFG, and this parameter was named blowout time (BOT. Chronic kidney disease (CKD was defined to be present when the estimated GFR was <60 mL/min per 1.73 m2. Pearson’s correlation coefficients were used to determine the relationship between the BOT and the kidney function. We also examined whether there were significant differences in all parameters in patients with and without CKD. Results. BOT was significantly correlated with the level of creatinine (r=-0.24, P=0.04, the estimated GFR (r=0.42, P=0.0003, cystatin C (r=-0.29, P=0.01, and urinary albumin excretion (r=-0.29, P=0.01. The BOT level in subjects with CKD was significantly lower than that in subjects without CKD (P=0.002. Conclusion. BOT in ONH by LSFG can detect the organ damage such as kidney dysfunction, CKD.

  12. Measurement uncertainty in pulmonary vascular input impedance and characteristic impedance estimated from pulsed-wave Doppler ultrasound and pressure: clinical studies on 57 pediatric patients

    International Nuclear Information System (INIS)

    Pulmonary vascular input impedance better characterizes right ventricular (RV) afterload and disease outcomes in pulmonary hypertension compared to the standard clinical diagnostic, pulmonary vascular resistance (PVR). Early efforts to measure impedance were not routine, involving open-chest measurement. Recently, the use of pulsed-wave (PW) Doppler-measured velocity to non-invasively estimate instantaneous flow has made impedance measurement more practical. One critical concern remains with clinical use: the measurement uncertainty, especially since previous studies only incorporated random error. This study utilized data from a large pediatric patient population to comprehensively examine the systematic and random error contributions to the total impedance uncertainty and determined the least error prone methodology to compute impedance from among four different methods. We found that the systematic error contributes greatly to the total uncertainty and that one of the four methods had significantly smaller propagated uncertainty; however, even when this best method is used, the uncertainty can be large for input impedance at high harmonics and for the characteristic impedance modulus. Finally, we found that uncertainty in impedance between normotensive and hypertensive patient groups displays no significant difference. It is concluded that clinical impedance measurement would be most improved by advancements in instrumentation, and the best computation method is proposed for future clinical use of the input impedance

  13. Application of a Modified Entropy Computational Method in Assessing the Complexity of Pulse Wave Velocity Signals in Healthy and Diabetic Subjects

    Directory of Open Access Journals (Sweden)

    Yi-Chung Chang

    2014-07-01

    Full Text Available Using 1000 successive points of a pulse wave velocity (PWV series, we previously distinguished healthy from diabetic subjects with multi-scale entropy (MSE using a scale factor of 10. One major limitation is the long time for data acquisition (i.e., 20 min. This study aimed at validating the sensitivity of a novel method, short time MSE (sMSE that utilized a substantially smaller sample size (i.e., 600 consecutive points, in differentiating the complexity of PWV signals both in simulation and in human subjects that were divided into four groups: healthy young (Group 1; n = 24 and middle-aged (Group 2; n = 30 subjects without known cardiovascular disease and middle-aged individuals with well-controlled (Group 3; n = 18 and poorly-controlled (Group 4; n = 22 diabetes mellitus type 2. The results demonstrated that although conventional MSE could differentiate the subjects using 1000 consecutive PWV series points, sensitivity was lost using only 600 points. Simulation study revealed consistent results. By contrast, the novel sMSE method produced significant differences in entropy in both simulation and testing subjects. In conclusion, this study demonstrated that using a novel sMSE approach for PWV analysis, the time for data acquisition can be substantially reduced to that required for 600 cardiac cycles (~10 min with remarkable preservation of sensitivity in differentiating among healthy, aged, and diabetic populations.

  14. Development of a 2.0W at 60K single-stage coaxial pulse tube cryocooler for long-wave infrared focal plane array applications

    Science.gov (United States)

    Dang, H. Z.; Wang, L. B.; Wu, Y. N.; Yang, K. X.; Li, S. S.; Shen, W. B.

    2010-04-01

    A 2.0W@60K single-stage coaxial pulse tube cryocooler has been developed to provide reliable low-vibration cooling for the space-borne long wave infrared focal plane array. The coaxial configuration result in a compact system and the inertance tube together with a gas reservoir serves as the only phase-shifting to realize a highly reliable system. The inertance tube consists of two parts with different inner diameter and length to obtain the desirable phase relationship. Both cold tip and warm flange integrated with fine slit heat exchanges fabricated with electro discharge machining technology to enhance heat exchange performance. A split Oxford-type linear compressor with dual-opposed piston configuration is connected to the cold finger with a 30 cm flexible metallic tube. The overall weight without control electronics is below 8 kg. The preliminary experiments show that a no-load temperature of 46 K and a cooling power of 2 W at 60 K with 104 W of input power at 300K reject temperature have been achieved.

  15. Kinetics of the Thermal Decomposition of Tetramethylsilane behind the Reflected Shock Waves in a Single Pulse Shock Tube (SPST) and Modeling Study

    Science.gov (United States)

    Parandaman, A.; Sudhakar, G.; Rajakumar, B.

    Thermal reactions of Tetramethylsilane (TMS) diluted in argon were studied behind the reflected shock waves in a single-pulse shock tube (SPST) over the temperature range of 1085-1221 K and pressures varied between 10.6 and 22.8 atm. The stable products resulting from the decomposition of TMS were identified and quantified using gas chromatography and also verified with Fourier Transform Infrared (FTIR) spectrometer. The major reaction products are methane (CH4) and ethylene (C2H4). The minor reaction products are ethane (C2H6) and propylene (C3H6). The initiation of mechanism in the decomposition of TMS takes plays via the Si-C bond scission by ejecting the methyl radicals (CH3) and trimethylsilyl radicals ((CH3)3Si). The measured temperature dependent rate coefficient for the total decomposition of TMS was to be ktotal = 1.66 ×1015 exp (-64.46/RT) s-1 and for the formation of CH4 reaction channel was to be k = 2.20 × 1014 exp (-60.15/RT) s-1, where the activation energies are given in kcal mol-1. A kinetic scheme containing 17 species and 28 elementary reactions was used for the simulation using chemical kinetic simulator over the temperature range of 1085-1221 K. The agreement between the experimental and simulated results was satisfactory.

  16. Electromagnetic Guide Wave Excitation Resource Optimal Design Based on isolated Current Pulse Group%基于孤立电流脉冲群的电磁导波激励源优化设计

    Institute of Scientific and Technical Information of China (English)

    李勇; 米东; 刘美全; 周海林

    2011-01-01

    目前,电磁导波检测系统的激励源大都采用重复电流脉冲群+高频大功率放大器输出大电流脉冲的方式,由于这种电流脉冲是连续的,平均功耗较大,成本高,不利于系统的简单化和实用化;通过电路分析和电路参数的优化选取,给出了电容储能放电产生孤立电流脉冲群作为电磁导波激励信号的新方法,整个系统设计简单,无需功率放大器放大,成本大为降低;实际放电波形表明:这种激励信号瞬时电流很高,能达到重复脉冲群激励信号的3倍以上,完全满足实际电磁导波检测要求.%The excitation resource of the electromagnetic guide wave detection system almost adopts the way of repeated current pulse group + high frequency and high power amplifier. That is a way which has continuous current pulse and high power consumption and high cost. A new way has been provided by circuit analysis and the optimal select of circuit parameter. The excitation resource of the electromagnetic guide wave is isolated current pulse group by capacitance energy storage and discharge. The system has the characteristic of simple and without power amplifier and low cost. The real discharge wave shows that this excitation signal has high instantaneous current and 3 times than that of repeated pulse group and the best demand for real electromagnetic guide wave detection.

  17. Impact of changes in systemic vascular resistance on a novel non-invasive continuous cardiac output measurement system based on pulse wave transit time: a report of two cases

    OpenAIRE

    Ishihara, Hironori; Tsutsui, Masato

    2013-01-01

    The inaccuracy of arterial waveform analysis for measuring continuos cardiac output (CCO) associated with changes in systemic vascular resistance (SVR) has been well documented. A new non-invasive continuous cardiac output monitoring system (esCCO) mainly utilizing pulse wave transit time (PWTT) in place of arterial waveform analysis has been developed. However, the trending ability of esCCO to measure cardiac output during changes in SVR remains unclear. After a previous multicenter study on...

  18. Determination of Diastolic Dysfunction Cut-Off Value by Tissue Doppler Imaging in Adults 70 Years of Age or Older: A Comparative Analysis of Pulsed-Wave and Color-Coded Tissue Doppler Imaging

    OpenAIRE

    Baek, Hee-Kyung; Park, Tae-Ho; Park, Sun-Yi; Kim, Jung-Hwan; Seo, Jeong-Min; Kim, Woo-Jae; Nam, Young-Hee; Kim, Moo-Hyun; Kim, Young-Dae

    2011-01-01

    Background and Objectives The cut-off value of diastolic dysfunction by tissue Doppler imaging (TDI) is affected by aging and modalities used (pulsed-wave vs. color-coded). The purpose of this study was to investigate the diastolic function of healthy elderly people and to determine the appropriate cut-off value of diastolic dysfunction in elderly individuals. Subjects and Methods Healthy volunteers (n=76) and patients with hypertension (n=51) aged ≥70 years underwent 2-dimensional and Dopple...

  19. Generation of spectrally-stable continuous-wave emission and ns pulses at 800 nm and 975 nm with a peak power of 4 W using a distributed Bragg reflector laser and a ridge-waveguide power amplifier

    Science.gov (United States)

    Klehr, A.; Wenzel, H.; Fricke, J.; Bugge, F.; Liero, A.; Hoffmann, Th.; Erbert, G.; Tränkle, G.

    2015-03-01

    Semiconductor based sources which emit high-power spectrally stable nearly diffraction-limited optical pulses in the nanosecond range are ideally suited for a lot of applications, such as free-space communications, metrology, material processing, seed lasers for fiber or solid state lasers, spectroscopy, LIDAR and frequency doubling. Detailed experimental investigations of 975 nm and 800 nm diode lasers based on master oscillator power amplifier (MOPA) light sources are presented. The MOPA systems consist of distributed Bragg reflector lasers (DBR) as master oscillators driven by a constant current and ridge waveguide power amplifiers which can be driven DC and by current pulses. In pulse regime the amplifiers modulated with rectangular current pulses of about 5 ns width and a repetition frequency of 200 kHz act as optical gates, converting the continuous wave (CW) input beam emitted by the DBR lasers into a train of short optical pulses which are amplified. With these experimental MOPA arrangements no relaxation oscillations in the pulse power occur. With a seed power of about 5 mW at a wavelength of 973 nm output powers behind the amplifier of about 1 W under DC injection and 4 W under pulsed operation, corresponding to amplification factors of 200 (amplifier gain 23 dB) and 800 (gain 29 dB) respectively, are reached. At 800 nm a CW power of 1 W is obtained for a seed power of 40 mW. The optical spectra of the emission of the amplifiers exhibit a single peak at a constant wavelength with a line width 50 dB. The output beams are nearly diffraction limited with beam propagation ratios M2lat ~ 1.1 and M2ver ~ 1.2 up to 4 W pulse power.

  20. 脉冲式与连续波式导航雷达反截获能力分析%Analysis of Anti-interception Capability of Pulsed and Continuous-wave Navigation Radars

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      为了分析脉冲雷达与连续波雷达的探测效能,重点研究了在不同蒸发波导高度条件下两种体制导航雷达的反截获能力。首先给出了脉冲式和连续波式导航雷达截获因子的度量方法,然后对这两种体制的雷达在标准大气和蒸发波导条件下的截获因子进行了仿真。仿真结果表明,在反截获方面,连续波式导航雷达明显优于脉冲式导航雷达。%To analyze the detection performance of pulsed and continuous-wave radars, this paper focuses on the anti-interception capability of two types of systems of navigation radars under the circumstances of various evaporation ducts’altitude. Firstly, the measurement method for intercept factors of pulsed and continuous-wave radars is given, and then the intercept factors of these two systems of radars are simulated on the condition of standard air pressure and evaporation ducts. Simulation results show that the continuous-wave type of navigation radar is superior to the pulsed type in terms of anti-interception.

  1. Modelling of the positive column of a medium-pressure Cs–Xe dc discharge affected by a millimetre wave pulse

    International Nuclear Information System (INIS)

    A time-dependent zero-dimensional kinetic model of the positive column (PC) of a medium-pressure Cs–Xe dc discharge was used to gain a better insight into the physical basics of plasma techniques for imaging and control of millimetre wave (MMW) beams. The model allowed one to study the effect of MMWs on the kinetic and electrical characteristics of the spatially homogeneous PC of a Cs–Xe dc discharge. We computed the PC plasma parameters for 30 Torr and 45 Torr xenon and discharge current densities of about 0.1 A cm−2. First, the dependences of the PC parameters on caesium density were calculated in the case of no MMWs incident on the PC plasma. Then, the temporal evolution of the parameters of the PC plasma affected by a long watt-scale Ka-band MMW pulse was modelled for caesium densities of about 3 × 1012 and 5 × 1012 cm−3. The calculations showed that the electron temperature in the PC plasma attained quasisteady-state values for about 1 µs after the beginning of the MMW pulse. The electron temperature rises by 0.2–0.3 eV as the MMW intensity increases from 0 to 1 W cm−2. The rise time of the electron density decreased with an increase in the MMW intensity W from about 1 ms for W = 0.15 W cm−2 to tens of microseconds for W > 1.5 W cm−2. The steady-state values of the electron density increased in proportion to W, if W −2. They were approximately constant for 0.5 −2 due to the nearly full ionization of caesium atoms in the PC plasma. Efficient xenon excitation and ionization for W > 3 W cm−2 could be a cause of the microwave breakdown of the homogeneous PC plasma. The results of the modelling are in good agreement with the published experimental data. (paper)

  2. Tailoring giant magnetoimpedance effect of Co-based microwires for optimum efficiency by self-designed square-wave pulse current annealing

    International Nuclear Information System (INIS)

    Herein, we systematically studied the effect of a novel square-wave pulse current annealing (SPCA) on the magnetic properties and microstructure of Co-based melt-extracted amorphous wires, and efficiently tailored the related experimental parameters by using numerical calculation of transient temperature rise during SPCA process. We obtained the optimal SPCA treatment (at 50 Hz, with amplitude of 90 mA for 480 s) can remarkably enhance the GMI property of as-prepared wires. At 10 MHz, the maximum GMI ratio [ΔZ/Z0]max and maxima response sensitivity ξmax of SPCA-treated wire increases to 202.60% and 305.74%/Oe, which is nearly two times and 1.5 times of 104.80% and 208.14%/Oe for as-cast wire, respectively. Especially, at 5 MHz, [ΔZ/Z0]max of SPCA-treated wire increases to 185.81%, which is 2.5 times of 73.69% for as-cast wire, and ξmax of SPCA-treated wire increases to 346.65%/Oe by less than two times of 190.16%/Oe for as-cast wire. From mictrostructural perspective, the notably observed role of atomic order orientation regimes and circular magnetic domain during stress releasing or structural relaxation by the co-action of high-density pulse magnetic field energy and thermal activation energy determines the optimum efficiency of SPCA, further to enhance circumferential permeability. In conclusion, SPCA treatment is expected to effectively improve GMI property of microwires, which can be used as sensitive materials for potential sensor application in detecting weak magnetic field. - Highlights: • Annealing parameters are optimized by transient temperature rising calculation. • SPCA as a novel annealing treatment has larger GMI ratio and field sensitivity. • GMI effect is generally related to annealed microstructures identified by XRD. • Domain observed by MFM to explain the enhanced GMI property for SPCA-ed wires. • Results indicate SPCA-ed wires are useful for potential GMI sensor applications

  3. Tailoring giant magnetoimpedance effect of Co-based microwires for optimum efficiency by self-designed square-wave pulse current annealing

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jingshun, E-mail: jingshun_liu@163.com [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Du, Zhaoxin [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Jiang, Sida; Shen, Hongxian [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li, Ze [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Xing, Dawei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Wen [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Sun, Jianfei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-07-01

    Herein, we systematically studied the effect of a novel square-wave pulse current annealing (SPCA) on the magnetic properties and microstructure of Co-based melt-extracted amorphous wires, and efficiently tailored the related experimental parameters by using numerical calculation of transient temperature rise during SPCA process. We obtained the optimal SPCA treatment (at 50 Hz, with amplitude of 90 mA for 480 s) can remarkably enhance the GMI property of as-prepared wires. At 10 MHz, the maximum GMI ratio [ΔZ/Z{sub 0}]{sub max} and maxima response sensitivity ξ{sub max} of SPCA-treated wire increases to 202.60% and 305.74%/Oe, which is nearly two times and 1.5 times of 104.80% and 208.14%/Oe for as-cast wire, respectively. Especially, at 5 MHz, [ΔZ/Z{sub 0}]{sub max} of SPCA-treated wire increases to 185.81%, which is 2.5 times of 73.69% for as-cast wire, and ξ{sub max} of SPCA-treated wire increases to 346.65%/Oe by less than two times of 190.16%/Oe for as-cast wire. From mictrostructural perspective, the notably observed role of atomic order orientation regimes and circular magnetic domain during stress releasing or structural relaxation by the co-action of high-density pulse magnetic field energy and thermal activation energy determines the optimum efficiency of SPCA, further to enhance circumferential permeability. In conclusion, SPCA treatment is expected to effectively improve GMI property of microwires, which can be used as sensitive materials for potential sensor application in detecting weak magnetic field. - Highlights: • Annealing parameters are optimized by transient temperature rising calculation. • SPCA as a novel annealing treatment has larger GMI ratio and field sensitivity. • GMI effect is generally related to annealed microstructures identified by XRD. • Domain observed by MFM to explain the enhanced GMI property for SPCA-ed wires. • Results indicate SPCA-ed wires are useful for potential GMI sensor applications.

  4. Pulsed-wave tissue Doppler imaging of the myocardium of cats with induced thyrotoxicosis Doppler tecidual pulsado do miocárdio de gatos com tirotoxicose induzida

    Directory of Open Access Journals (Sweden)

    Daniel Capucho de Oliveira

    2011-06-01

    Full Text Available Left ventricular myocardial motion was quantified using pulsed-wave tissue Doppler imaging (PW-TDI in nine adult cats before and after thyrotoxicosis induction. In order to induce thyrotoxicosis, all cats were given 150µg kg-1 of levothyroxine sodium as a single oral dose each day for 10 weeks. PW-TDI examinations were performed immediately before the induction and by the end of the experimental protocol. An increase in myocardial motion velocity was documented at the interventricular septum level, demonstrated by an elevation in systolic (Sa, and early (Ea and late (Aa diastolic waves (PA velocidade de movimentação miocárdica do ventrículo esquerdo foi quantificada por meio de exames ecocardiográficos com Doppler tecidual pulsado (PW-TDI em nove gatos adultos antes e após indução à tirotoxicose. Para indução da tirotoxicose, todos os gatos receberam doses diárias de 150mg kg-1 de levotiroxina sódica, por via oral, durante 10 semanas. Os exames de PW-TDI foram realizados imediatamente antes da indução e ao final do protocolo experimental. Uma elevação na velocidade de movimentação miocárdica foi documentada ao nível do septo interventricular, demonstrado por um aumento das ondas sistólica (Sa e diastólicas (Ea e Aa; P<0,05. No entanto, nenhuma alteração nos valores de Sa, Ea e Aa foi encontrada ao nível da parede livre do ventrículo esquerdo. A frequência cardíaca aumentou significativamente entre os momentos experimentais, sendo que três animais apresentaram fusão das ondas Aa e Ea ao final do experimento. O protocolo experimental utilizado neste estudo causou alterações na velocidade de movimentação do miocárdio ventricular esquerdo, mas sem causar danos à função diastólica do ventrículo esquerdo.

  5. Traveling wave laser system

    International Nuclear Information System (INIS)

    The invention broadly involves a method and means for generating a traveling wave laser pulse and is basically analogous to a single pass light amplifier system. However, the invention provides a traveling wave laser pulse of almost unlimited energy content, wherein a gain medium is pumped in a traveling wave mode, the traveling wave moving at essentially the velocity of light to generate an amplifying region or zone which moves through the medium at the velocity of light in the presence of directed stimulating radiation, thereby generating a traveling coherent, directed radiation pulse moving with the amplification zone through the gain medium. (U.S.)

  6. Reduction in visceral adiposity is highly related to improvement in vascular endothelial dysfunction among obese women: an assessment of endothelial function by radial artery pulse wave analysis.

    Science.gov (United States)

    Park, Si-Hoon; Shim, Kyung-Won

    2005-08-31

    Because obesity is frequently complicated by other cardiovascular risk factors, the impact of a reduction in visceral adiposity on vascular endothelial dysfunction (VED) in obese patients is difficult to determine. In the present study, we evaluated the impact of a reduction in visceral adiposity on VED in obese women. Thirty-six premenopausal obese women (BMI >/= 25 kg/m2) without complications were enrolled in the study. VED was evaluated by determining the augmentation index (AIx) from radial artery pulse waves obtained by applanation tonometry. Changes in AIx in response to nitroglycerin- induced endothelium-independent vasodilatation (DeltaAIx-NTG) and in response to salbutamol administration (DeltaAIx-Salb) were determined before and after weight reduction. After a 12-week weight reduction program, the average weight loss was 7.96 +/- 3.47 kg, with losses of 21.88 +/- 20.39 cm2 in visceral fat areas (p analysis combined with provocative pharmacological testing demonstrated preserved endothelium-independent vasodilation in healthy premenopausal obese women (DeltaAIx-NTG: 31.36 +/- 9.80% before weight reduction vs. 28.25 +/- 11.21% after weight reduction, p > 0.1) and an improvement in endothelial-dependent vasodilation following weight reduction (DeltaAIx-Salb: 10.03 +/- 6.49% before weight reduction vs. 19.33 +/- 9.28% after reduction, p VED. This finding suggests that reduction of visceral adiposity may be as important as the control of other major risk factors in the prevention of atherosclerosis in obese women. PMID:16127776

  7. Relativistic spherical plasma waves

    CERN Document Server

    Bulanov, S S; Schroeder, C B; Zhidkov, A G; Esarey, E; Leemans, W P

    2011-01-01

    Tightly focused laser pulses as they diverge or converge in underdense plasma can generate wake waves, having local structures that are spherical waves. Here we report on theoretical study of relativistic spherical wake waves and their properties, including wave breaking. These waves may be suitable as particle injectors or as flying mirrors that both reflect and focus radiation, enabling unique X-ray sources and nonlinear QED phenomena.

  8. Traveling wave laser system

    International Nuclear Information System (INIS)

    A method is described for generating a traveling wave laser pulse of almost unlimited energy content wherein a gain medium is pumped into a traveling wave mode, the traveling wave moving at essentially the velocity of light to generate an amplifying region or zone which moves through the medium at the velocity of light in the presence of directed stimulating radiation, thereby generating a traveling coherent, directed radiation pulse moving with the amplification zone through the gain medium. (U.S.)

  9. Generation of high energy square-wave pulses in all anomalous dispersion Er:Yb passive mode locked fiber ring laser.

    Science.gov (United States)

    Semaan, Georges; Ben Braham, Fatma; Salhi, Mohamed; Meng, Yichang; Bahloul, Faouzi; Sanchez, François

    2016-04-18

    We have experimentally demonstrated square pulses emission from a co-doped Er:Yb double-clad fiber laser operating in anomalous dispersion DSR regime using the nonlinear polarization evolution technique. Stable mode-locked pulses have a repetition rate of 373 kHz with 2.27 µJ energy per pulse under a pumping power of 30 W in cavity. With the increase of pump power, both the duration and the energy of the output square pulses broaden. The experimental results demonstrate that the passively mode-locked fiber laser operating in the anomalous regime can also realize a high-energy pulse, which is different from the conventional low-energy soliton pulse. PMID:27137277

  10. Bragg grating rogue wave

    CERN Document Server

    Degasperis, Antonio; Aceves, Alejandro B

    2015-01-01

    We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing, may lead to extreme waves at extremely low powers.

  11. Bragg grating rogue wave

    Energy Technology Data Exchange (ETDEWEB)

    Degasperis, Antonio [Dipartimento di Fisica, “Sapienza” Università di Roma, P.le A. Moro 2, 00185 Roma (Italy); Wabnitz, Stefan, E-mail: stefan.wabnitz@unibs.it [Dipartimento di Ingegneria dell' Informazione, Università degli Studi di Brescia and INO-CNR, via Branze 38, 25123 Brescia (Italy); Aceves, Alejandro B. [Southern Methodist University, Dallas (United States)

    2015-06-12

    We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing may lead to extreme waves at extremely low powers.

  12. 时间反演脉冲电磁波在双负材料中传播特性研究%Propagation characteristics of time reversal pulsed electromagnetic waves in double negative materials

    Institute of Scientific and Technical Information of China (English)

    赵德双; 岳文君; 余敏; 张升学

    2012-01-01

    With the full time-domain electromagnetic simulation technique,the time-domain propagation properties such as the temporal pulse waveform,the pulse compression and the electric field distribution inside the material are comparably investigated by transmitting the time-reversal pulsed electromagnetic wave and the pulsed electromagnetic wave through the double negative material of the Smith structure,respectively.The results show that after the time-reversal pulsed electromagnetic wave passes through the double negative material,the received electromagnetic wave exhibits remarkable spatial and temporal focusing at the location of the initial excitation. The most interesting physical phenomenon is that the peak values of the electric field inside the double negative material become smaller and tend to be uniform in the magnitude.These novel physical phenomena would be very helpful for developing new electronic devices and systems with double negative materials for the purpose of high power applications.%利用全时域电磁仿真技术,对比研究了时间反演脉冲电磁波和脉冲电磁波透过Smith结构双负材料后的时域波形、脉宽压缩以及材料内部空间电场峰值强度分布等时域传播特性.结果表明:时间反演脉冲电磁波在透过双负材料后,在初始源激励处表现出良好的时间和空间聚焦特性.更重要的是,在双负材料内部,观测到了电场峰值强度减弱、截面电场峰值强度趋向均衡分布等新型的物理现象.这些物理现象对发展能够承受大功率新型的双负材料电子器件及其应用系统很有参考研究价值.

  13. 三极管2SC3402方波电磁脉冲效应实验研究%Experimental studies on square wave electromagnetic pulse effect for the semiconductor triode 2SC3402

    Institute of Scientific and Technical Information of China (English)

    王瑞军; 康洪波

    2009-01-01

    Silicon micro-wave low-noise triode, such as 2SC3402 has carried on experiments of the square wave electromagnetic pulse effect and get some initial conclusions. The experiment follows that the triode's most sensitive position of square wave electromagnetic pulse is the collector junction. The most sensitive parameters are the reverse breakdown voltage V_(BRCEO) between collector and emitter.%针对硅微波低噪声三极管2SC3402进行方波电磁脉冲效应实验,主要研究三极管在方波电磁脉冲作用下哪些部位对电磁脉冲最为敏感,哪些电参数最容易发生变化.实验采用方波电磁脉冲发生器对三极管进行方波电磁脉冲注入,观察三极管电参数的变化.实验结果表明,三极管对电磁脉冲最敏感的部位是集电结,最灵敏参数是CE反向击穿电压V_(BRCEO).

  14. Performance Analysis of Multiple Access 60 GHz System Using Frequency-shifted Gaussian Pulse and Non-carrier PSWF Pulse

    OpenAIRE

    Hao Zhang; Wei Shi; Tingting Lu; Jingjing Wang; Xinjie Wang

    2013-01-01

    In this paper, a kind of impulse radio (IR) 60 GHz pulse based on Prolate Spheroidal Wave Functions (PSWF) is proposed. The capacity and performance for multiple access 60 GHz communication system based on carrier pulse and impulse radio pulse are analyzed separately. Both frequency-shifted Gaussian pulse and Prolate Spheroidal Wave Functions (PSWF) pulse are considered and devised according to the federal communication commission (FCC) power constraints. Pulse position modulation (PPM) with ...

  15. Distortion of ultrashort pulses caused by aberrations

    Science.gov (United States)

    Horváth, Z. L.; Kovács, A. P.; Bor, Zs.

    The effect of the primary wave aberrations (spherical aberration, astigmatism and coma) on ultrashort pulses is studied by the Nijboer-Zernike theory. The results of the geometrical and the wave optical treatments are compared.

  16. Whispering Gallery Pulse Compressor

    International Nuclear Information System (INIS)

    A barrel-like cavity resonant at a whispering gallery mode is known as capable to provide a SLED-like rf pulse compression. To enhance the power handling capacity of the compressor, we propose to use a coupler based on a wave tunneling through a continuous slot. A modeling low power 11.4 GHz experiment proved to be consistent with theory. A preliminary technical design for an evacuated high-power compressor has also been developed. According to a theory, a twin-cavity version of the device can efficiently compress microwave pulses produced with sources of limited bandwidth, in particular frequency-chirped pulses

  17. 规律运动增加内皮祖细胞数量和功能改善衰老血管弹性*****☆%Regular exercise improves age-related decline in arterial elasticity by enhancing number and activity of endothelial progenitor cells

    Institute of Scientific and Technical Information of China (English)

    杨震; 张媛媛; 夏文豪; 罗初凡; 陈龙; 靳亚飞; 欧志君; 廖新学; 陶军

    2013-01-01

    circulating endothelial progenitor cel s. OBJECTIVE: To investigate whether regular exercise-induced enhanced circulating endothelial progenitor cel s improves age-related decline in arterial elasticity in healthy men. METHODS:Effects of regular exercise on circulating endothelial progenitor cel s of 10 older and 10 young healthy men undergoing 3 months regular exercise were observed. Flow cytometry analysis was performed to evaluate the number of CD34 and KDR double-positive labeled circulating endothelial progenitor cel s before and after exercise, and acetylated low-density lipoprotein;and lectin fluorescent staining method was used to evaluate the number of cultured endothelial progenitor cel s. The migratory and proliferative activities of endothelial progenitor cel s were also evaluated. In addition, brachial-ankle pulse wave velocities of older and young sedentary healthy men were measured. RESULTS AND CONCLUSION:Compared with young healthy men, the older healthy men exhibited decreased number and activity of circulating endothelial progenitor cel s and increased brachial-ankle pulse wave velocities. Flow cytometry analysis showed that the circulating endothelial progenitor cel s positive for CD34 and KDR in the peripheral blood increased after regular exercise. The acetylated-low-density lipoprotein and lectin fluorescent staining method indicated that the cultured endothelial progenitor cel s also increased after exercise. The proliferative and migratory activities of cultured endothelial progenitor cel s were significantly higher after exercise. However, the increased number and activity of circulating endothelial progenitor cel s and decreased brachial-ankle pulse wave velocities of older sedentary healthy men were higher. There was a closely positive correlation between increased circulating endothelial progenitor cel s and decreased brachial-ankle pulse wave velocities. Multivariate analysis identified increased proliferative activity of circulating endothelial

  18. A Compact High Voltage Pulse Generator for Bounded-wave EMP Simulator%用于有界波模拟器的紧凑型纳秒脉冲源

    Institute of Scientific and Technical Information of China (English)

    谢霖燊; 贾伟; 郭帆; 陈维青; 陈志强; 金廷军

    2014-01-01

    With the development of electromagnetic weapons, nuclear electromagnetic pulse and its engineering protection technology has attracted world-wide attention. For simulating the electromagnetic pulse environment, a compact high voltage pulse generator was developed. The erected waveform with~1.6ns rise time, 42ns pulse width, 60kV peak value can be produced when this generator is connected to bounded-wave EMP simulator of the equivalent impedance of 120 ohms. Design considerations, system architecture, and experimental results of the generator are presented in this paper.%随着电磁武器的发展,核电磁脉冲及其工程防护技术受到各国的普遍关注。为模拟电磁脉冲环境,研制了一台紧凑型纳秒脉冲源,与有界波模拟器配合可产生的双指数波形前沿~1.6ns,脉宽42ns,幅值可达60kV。本文介绍了脉冲源的设计与调试结果。

  19. Experimental research on pulse forming based on high-temperature SMES applied in pulsed power

    Science.gov (United States)

    Zhou, Yusheng; Kuang, Jianghua; Tang, Yuejin; Song, Meng; Wei, Bin; Cheng, Shijie; Pan, Yuan

    2009-03-01

    To research the key problems of storage energy and pulse forming in pulsed power, a pulse magnet made of Bi2223/Ag high-temperature superconducting (HTS) tapes applied in pulsed power experiment was developed. After determining electromagnetic characteristics of the magnet, a pulse forming network was designed. HTS magnet was immersed in liquid nitrogen bath, experiments were carried out about discharging pulse current to resistance load based on HTS magnet energy storage (SMES). The results show that pulse current waves were obtained through adjusted circuit construction and magnet parameters by acting delay of switches in the pulse forming network. The technical schemes about pulse forming based on SMES were presented.

  20. Plasma response to transient high voltage pulses

    Indian Academy of Sciences (India)

    S Kar; S Mukherjee

    2013-07-01

    This review reports on plasma response to transient high voltage pulses in a low pressure unmagnetized plasma. Mainly, the experiments are reviewed, when a disc electrode (metallic and dielectric) is biased pulsed negative or positive. The main aim is to review the electron loss in plasmas and particle balance during the negative pulse electrode biasing, when the applied pulse width is less than the ion plasma period. Though the applied pulse width is less than the ion plasma period, ion rarefaction waves are excited. The solitary electron holes are reviewed for positive pulsed bias to the electrode. Also the excitation of waves (solitary electron and ion holes) is reviewed for a metallic electrode covered by a dielectric material. The wave excitation during and after the pulse withdrawal, excitation and propagation characteristics of various electrostatic plasma waves are reviewed here.

  1. Central blood pressure and pulse wave velocity: relationship to target organ damage and cardiovascular morbidity-mortality in diabetic patients or metabolic syndrome. An observational prospective study. LOD-DIABETES study protocol

    Directory of Open Access Journals (Sweden)

    Castaño-Sánchez Carmen

    2010-03-01

    Full Text Available Abstract Background Diabetic patients show an increased prevalence of non-dipping arterial pressure pattern, target organ damage and elevated arterial stiffness. These alterations are associated with increased cardiovascular risk. The objectives of this study are the following: to evaluate the prognostic value of central arterial pressure and pulse wave velocity in relation to the incidence and outcome of target organ damage and the appearance of cardiovascular episodes (cardiovascular mortality, myocardial infarction, chest pain and stroke in patients with type 2 diabetes mellitus or metabolic syndrome. Methods/Design Design: This is an observational prospective study with 5 years duration, of which the first year corresponds to patient inclusion and initial evaluation, and the remaining four years to follow-up. Setting: The study will be carried out in the urban primary care setting. Study population: Consecutive sampling will be used to include patients diagnosed with type 2 diabetes between 20-80 years of age. A total of 110 patients meeting all the inclusion criteria and none of the exclusion criteria will be included. Measurements: Patient age and sex, family and personal history of cardiovascular disease, and cardiovascular risk factors. Height, weight, heart rate and abdominal circumference. Laboratory tests: hemoglobin, lipid profile, creatinine, microalbuminuria, glomerular filtration rate, blood glucose, glycosylated hemoglobin, blood insulin, fibrinogen and high sensitivity C-reactive protein. Clinical and 24-hour ambulatory (home blood pressure monitoring and self-measured blood pressure. Common carotid artery ultrasound for the determination of mean carotid intima-media thickness. Electrocardiogram for assessing left ventricular hypertrophy. Ankle-brachial index. Retinal vascular study based on funduscopy with non-mydriatic retinography and evaluation of pulse wave morphology and pulse wave velocity using the SphygmoCor system. The

  2. Pulse Wave Velocity for the Diagnosis of Pseudohypertension%脉搏波传导速度在假性高血压诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    胡静; 邓辉胜

    2011-01-01

    目的 采用踝臂脉搏波传导速度评价动脉硬化,为假性高血压诊断提供参考.方法 冠状动脉造影患者30例,造影结束后同步测量肱动脉内直接血压及间接血压各3次,计算直接血压与间接血压收缩压差值和直接血压与间接血压舒张压差值;并应用动脉硬化检测仪测定双侧踝臂脉搏波传导速度,并获得年龄、疾病、体质指数、血脂参数.根据收缩压差值或舒张压差值是否大于10 mmHg分为假性高血压组和非假性高血压组,对各项变量进行统计学分析.结果 两组间的年龄、性别比例、体质指数、吸烟史比例、冠心病比例、耱尿病比例、高脂血症比例、血脂水平相近,差异无统计学意义(P>0.05);脉压(P=0.001)、无创收缩压(P=0.018)、无创血压与直接血压差值差异均有统计学(P<0.05);假性高血压组患者脉搏波传导速度与非假性高血压组患者比较差异具有统计学意义(P=0.029).根据统计学操作者工作特征曲线得出踝臂脉搏波传导速度>1896.0 cm/s时,预测假性高血压具有最高的敏感度(80.0%)和特异度(73.3%).Pearson相关分析得出两者的Pearson相关系数为0.431,具有中等相关性.结论 根据踝臂脉搏波传导速度的异常可对假性高血压的诊断有参考价值.%Aim To assess the arteriosclerosis by pulse wave velocity (PWV) for providing a reference for the diagnosis of pseudohypertension. Methods Thirty inpatients (male 17, female 13) with coronary angiography whose ages were between 55 -85 years, were divided into two groups, one group was the pseudohypertension, the other was the comparison. The brachial artery blood pressure and the indirect blood pressure were measured three times simultaneously after coronary angiography, and the difference between direct and indirect systolic and diastolic blood pressure was calculated. The bilateral ankle-brachial PWV(BaPWV) were measured using the atherosclerosis detector and

  3. 脉冲平面波斜入射旋转对称体电磁散射的FDTD算法%FDTD Method for Electromagnetic Scattering by Body of Revolution with Obliquely Incident Pulse Plane Wave

    Institute of Scientific and Technical Information of China (English)

    关福宏; 陈彬; 陈海林; 方大纲; 俞文明; 张力军

    2007-01-01

    We present a method for electromagnetic scattering with obliquely incident pulse plane wave using BOR-FDTD(body of revolution finite-difference time-domain)method.The obliquely incident pulse plane wave is expanded in a cylindrical coordinate and a total-field/scattered-field formulation is introduced as excitation.The method is validated by comparing with the method of moments.It shows good agreement.%提出一种应用时域有限差分算法求解脉冲平面波斜入射时旋转对称体散射问题的方法.对斜入射脉冲平面波在圆柱坐标系下进行分解、应用总场/散射场连接边界、PML吸收边界条件.通过与矩量法分析结果的比较,验证了该方法的有效性.

  4. Research on Environmental Adaptability Design Method of Hot-wire EED under Pulse Electromagnetic Wave%电热火工品脉冲电磁波环境适应性设计方法研究

    Institute of Scientific and Technical Information of China (English)

    褚恩义; 白颖伟; 任炜; 程加奇

    2013-01-01

    In order to reduce the harm of pulse electromagnetic wave for hot-wire EED, the TVS diode was applied, and the protective circuit with certain function was designed. The test showed that TVS diode could release the induced energy and didn’t have obvious effect on the output of EED. This study provided an environmental adaptability design method for hot-wire EED under pulse electromagnetic wave.%为了衰减并有效防护脉冲电磁波对电热火工品的危害,采用TVS二极管,设计了具有特定功能的保护电路,用于脉冲电磁波危害的防护。测试结果表明,TVS二极管能较好地泄放电热火工品脉冲电磁波环境下的感应能量,并且对火工品的电爆输出性能无显著影响。本研究为电热火工品的抗电磁脉冲适应性设计提供了一种方法。

  5. Potential of M-Wave Elicited by Double Pulse for Muscle Fatigue Evaluation in Intermittent Muscle Activation by Functional Electrical Stimulation for Motor Rehabilitation

    OpenAIRE

    Naoto Miura; Takashi Watanabe

    2016-01-01

    Clinical studies on application of functional electrical stimulation (FES) to motor rehabilitation have been increasing. However, muscle fatigue appears early in the course of repetitive movement production training by FES. Although M-wave variables were suggested to be reliable indices of muscle fatigue in long lasting constant electrical stimulation under the isometric condition, the ability of M-wave needs more studies under intermittent stimulation condition, because the intervals between...

  6. Efficient terahertz wave generation from GaP crystals pumped by chirp-controlled pulses from femtosecond photonic crystal fiber amplifier

    International Nuclear Information System (INIS)

    A chirp-tunable femtosecond 10 W, 42 MHz photonic-crystal-fiber oscillator-amplifier system that is capable of delivering sub-60 fs light pulses at 1040 nm is used to demonstrate high-efficiency terahertz radiation generation via optical rectification in GaP crystals only a few millimeters in length. The optimization of the chirp of the fiber-laser pulses is shown to radically enhance the terahertz output, indicating one possible way to more efficiently use these extended nonlinear crystals in compact fiber-pumped terahertz radiation sources

  7. Pulse on Pulse

    DEFF Research Database (Denmark)

    Schmidt, Ulrik; Carlson, Merete

    2012-01-01

    of the visitor’s beating heart to the blink of a fragile light bulb, thereby transforming each light bulb into a register of individual life. But at the same time the blinking light bulbs together produce a chaotically flickering light environment composed by various layers of repetitive rhythms, a vibrant...... and pulsating ‘room’. Hence, the visitors in Pulse Room are invited into a complex scenario that continuously oscillates between various aspects of signification (the light bulbs representing individual lives; the pulse itself as the symbolic ‘rhythm of life’) and instants of pure material processuality...... (flickering light bulbs; polyrhythmic layers). Taking our point of departure in a discussion of Gilles Deleuze’s concepts of modulation and signaletic material in relation to electronic media, we examine how the complex orchestration of pulsation between signification and material modulation produces...

  8. Electron acceleration experiment using a plasma wave generated by two beating laser pulses. Study of the 3 MeV electron beam monitor using optical transition radiation and magnetic spectrograph

    International Nuclear Information System (INIS)

    This thesis presents my contributions to the electron acceleration experiment using a plasma wave generated by two beating laser pulses at Ecole Polytechnique, Palaiseau, France. The first chapter describes the principle of particle acceleration by laser generated plasma waves. In order to estimate the energy gain, I examine the influence of the plasma wave's longitudinal profile and I obtain a gain of about 1 MeV over an acceleration length of 3 mm. In the second chapter, I present the beam monitor for the injected 3 MeV electron beam. This beam monitor uses optical transition radiation and has a spatial resolution of 10 μm. It is used to align of the laser beam and the electron beam and thus to control the injection of the electrons into the plasma. The third chapter describes the design of the magnetic spectrograph used to analyze the energy spectrum of the accelerated electrons. The study of the class of stigmatic dipole magnets leads to the selection of a quadrupole-dipole combination. This spectrograph is stigmatic at injection energy (3 MeV) and has a large energy range as well as a high angular acceptance. (author)

  9. Molecular orientation via a dynamically induced pulse-train: Wave packet dynamics of NaI in a static electric field

    DEFF Research Database (Denmark)

    Marquetand, P.; Materny, A.; Henriksen, Niels Engholm;

    2004-01-01

    We regard the rovibrational wave packet dynamics of NaI in a static electric field after femtosecond excitation to its first electronically excited state. The following quasibound nuclear wave packet motion is accompanied by a bonding situation changing from covalent to ionic. At times when the...... charge separation is present, i.e., when the bond-length is large, a strong dipole moment exists and rotational excitation takes place. Upon bond contraction, the then covalently bound molecule does not experience the external field. This scenario repeats itself periodically. Thus, the vibrational...

  10. 基于容积脉搏波的无创连续血压测量系统%A Non-invasive Continuous Blood Pressure Measurement System Based on Plethysmographic Pulse Wave

    Institute of Scientific and Technical Information of China (English)

    梁永波; 陈真诚; 朱健铭; 殷世民

    2013-01-01

    Objective To develop a non-invasive continuous blood pressure measurement system without the cuff based on plethysmographic pulse wave. Methods A blood pressure estimation equation was established by the stepwise regression analysis on blood pressure and pulse wave transit time which was extracted from a single circle of plethysmographic pulse wave, and then the non-invasive continuous blood pressure measurement was realized. Results Compared blood pressure value with detection by the system and Yu-Yue brand mercury sphygmomanometer from various populations, the results indicated that the two methods exhibit good coherence , and the measurement error is better than the Association for the Advancement of Medical Instrumentation (AAMI) recommendation standard. Conclusion Compared with traditional blood pressure measurement method , the non-invasive continuous blood pressure measurement method is more convenient. It can measure blood pressure continuously without cuff and invasion, and may have promising application in the future.%目的 设计一种基于容积脉搏波的无袖套连续血压测量系统.方法 从单一容积脉搏波中提取脉搏波传导时间,经逐步回归分析与血压建立血压估算方程,实现无创连续血压测量.结果 通过对不同人群血压检测,并与鱼跃牌水银血压计进行对比,结果表明该方法和传统方法具有较好的测试一致性,测量误差优于美国医疗仪器促进协会(AAMI)推荐标准.结论 该方法同传统血压测量方法相比,测量方便,可彻底摆脱缚带,并能实现无创连续测量,具有更广阔的应用前景.

  11. A new type of modified wave airborne electromagnetic pulse transmitting system%一种新型的组合波航空电磁脉冲发射系统

    Institute of Scientific and Technical Information of China (English)

    李军峰; 李文杰; 刘俊杰

    2014-01-01

    It is difficult to achieve the ideal square pulse current especially with high inductor load, low loop resistance and low input voltage;therefore, time domain airborne electromagnetic systems such as GEOTEM mostly adopt the half sine wave transmitting circuit to realize the large magnetic moment of emission. This paper describes the design of a novel quasi⁃resonant modified pulse emission cir⁃cuit. The modified waveform current generated by this special transmitter with the short edge times is somewhat similar to square wave⁃form, the ideal wave form of broad band transient. On such a basis, a set of fix⁃wing airborne electromagnetic pulse transmitting system has been developed recently, whose pulse current reaches 650 A and peak moment is up to 500 000 Am2 .%由于在低压输入,多匝、低阻发射线圈条件下很难实现理想的方波电流脉冲,GEOTEM等国外经典的时间域航空电磁系统大都采用半正弦波发射电路来实现大磁矩发射。笔者设计了一种新型的准谐振组合波脉冲发射电路,能够在提高通断速度的同时实现近似方波的组合波脉冲发射,有利于提高航空电磁勘查系统的分辨能力。在此基础上,成功研发了一套固定翼航空电磁脉冲发射系统,可激发基频可选、脉宽可调的双极性组合波电流脉冲,电流脉冲的幅值达到650 A,峰值磁矩达到50万Am2。

  12. STUCTURE OF PULSED BED

    Directory of Open Access Journals (Sweden)

    I. A. Bokun

    2014-01-01

    Full Text Available The structure of pulsed layer is proposed which can be suggested as a state of particulates that is blown by intermittent gas flow with speed which has the force to start material moving. Layer during one cycle is in a suspension, falling down and immobile state resulting in changes of particles arrangement as well as ways of gas flowing through layer. Moreover, it allows carrying out effective interphase heat exchange even adamant real granulation.The process of formation of impact flows is considered aw well as their influence on formation of air bubbles in pulsed layer. At startup of air blast the balance between the force of hydro-dynamic resistance is broken, on one side, and forces of gravity, particles inertia and their links with walls on the other side. The layer is transferred in the state of pulsed pseudo-fluidization, and presents gas-disperse mixture, inside of which impulse of pressure increasing is spreading to all sides as pressure waves (compression. These waves are the sources of impact flows’ formation, the force of which is two times more than during the stationary flow.The waves of pressure are divided into weak and strong ones depending on movement velocity within gas-disperse system. Weak waves are moving with a sound speed and strong ones in active phase of pulsed layer are moving over the speed of sound limit within gas-disperse system. The peculiarity of strong wave is that parameters of system (pressure, density and others are changing in discrete steps.The article describes the regime of layer’s falling down in the passive stage of cycle, which begins after finishing of gas impulse action. And suspension layer of moving up granular material is transferred in the state of falling resulting in change of the layer structure.

  13. Developing classification indices for Chinese pulse diagnosis

    CERN Document Server

    Shu, Jian-Jun

    2014-01-01

    Aim: To develop classification criteria for Chinese pulse diagnosis and to objectify the ancient diagnostic technique. Methods: Chinese pulse curves are treated as wave signals. Multidimensional variable analysis is performed to provide the best curve fit between the recorded Chinese pulse waveforms and the collective Gamma density functions. Results: Chinese pulses can be recognized quantitatively by the newly-developed four classification indices, that is, the wave length, the relative phase difference, the rate parameter, and the peak ratio. The new quantitative classification not only reduces the dependency of pulse diagnosis on Chinese physician's experience, but also is able to interpret pathological wrist-pulse waveforms more precisely. Conclusions: Traditionally, Chinese physicians use fingertips to feel the wrist-pulses of patients in order to determine their health conditions. The qualitative theory of the Chinese pulse diagnosis is based on the experience of Chinese physicians for thousands of year...

  14. A Measurement Method of Time Jitter of a Laser Pulse with Respect to the Radio-Frequency Wave Phase in a Photocathode Radio-Frequency Gun

    Institute of Scientific and Technical Information of China (English)

    刘圣广; 李永贵; 王鸣凯

    2002-01-01

    In a photo-cathode radio-frequency (rf) gun, the micro-bunched charge output from the gun is dependent linearly on the laser injection phase, due to the Scottay effect in the process of photoemission and the procedure of the electron longitudinal acceleration. Based on this principle, a new method is proposed, which should be utilized to measure the time jitter between the driving laser pulse and the rf phase with a very high resolution of a few tens of femtoseconds.

  15. Validation of a new non-invasive blood pressure measurement method on mice via pulse wave propagation time measurement on a cuff

    OpenAIRE

    Nguyen, Xuan P.; Kronemayer, Ralf; Herrmann, Peter; Mejía, Atila; Daw, Zamira; Nguyen, Xuan D.; Kränzlin, Bettina; Gretz, Norbert

    2011-01-01

    In the present article, we describe the validation of a new non-invasive method for measuring blood pressure (BP) which also enables to determine the three BP values: systolic, diastolic and mean value. Our method is based on the pulse transit time (PTT) measurement along an artery directly at the BP cuff. The accuracy of this method was evaluated by comparison with the direct simultaneous measurement of blood pressure from 40 anesthetized female mice. Close correlation ...

  16. Pulse waveform analysis as a bridge between pulse examination in Chinese medicine and cardiology.

    Science.gov (United States)

    de Sá Ferreira, Arthur; Lopes, Agnaldo José

    2013-04-01

    Pulse examination was probably the earliest attempt to distinguish between health and illnesses. Starting at the pre-Hippocratic era, Chinese medicine practitioners developed techniques for pulse examination and defined pulse images based on their perceptions of pulse waveforms at the radial artery. Pulse images were described using basic variables (frequency, rhythm, wideness, length, deepness, and qualities) developed under philosophical trends such as Taoism and Confucianism. Recent advances in biomedical instrumentation applied to cardiology opened possibilities to research on pulse examination based on ancient Chinese medical theories: the pulse wave analysis. Although strongly influenced by philosophy, some characteristics used to describe a pulse image are interpretable as parameters obtained by pulse waveform analysis such as pulse wave velocity and augmentation index. Those clinical parameters reflect concepts unique to Chinese medicine - such as yinyang - while are based on wave reflection and resonance theories of fluids mechanics. Major limitations for integration of Chinese and Western pulse examination are related to quantitative description of pulse images and pattern differentiation based on pulse examination. Recent evidence suggests that wave reflection and resonance phenomena may bridge Chinese medicine and cardiology to provide a more evidence-based medical practice. PMID:23546634

  17. Time-resolved processes in a pulsed electrical discharge in water generated with shock wave assistance in a plate-to-plate configuration

    Czech Academy of Sciences Publication Activity Database

    Stelmashuk, Vitaliy

    2014-01-01

    Roč. 47, č. 49 (2014), s. 495204-495204. ISSN 0022-3727 Institutional support: RVO:61389021 Keywords : underwater discharge * streamers * spark * cavitation bubble * shock wave Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.721, year: 2014 http://iopscience.iop.org/0022-3727/47/49/495204/pdf/0022-3727_47_49_495204.pdf

  18. Methods for High Power EM Pulse Measurement

    OpenAIRE

    Fiala, P.; Drexler, P.

    2006-01-01

    There are some suitable methods for the measurement of ultra-short solitary electromagnetic pulses that can be generated by high power pulsed generators. The measurement methods properties have to correspond to the fact whether we want to measure pulses of voltage, current or free-space electromagnetic wave. The need for specific measurement methods occurred by the development of high power microwave pulse generator. Applicable methods are presented in this paper. The method utilizing Faraday...

  19. Prospective Study of Arterial Stiffness and Subsequent Cognitive Decline Among Community-Dwelling Older Japanese

    Directory of Open Access Journals (Sweden)

    Yu Taniguchi

    2015-09-01

    Full Text Available Background: Brachial-ankle pulse wave velocity (baPWV is inversely associated with cognitive function. However, it is not known whether baPWV predicts cognitive decline (CD in later life. We examined whether or not baPWV is an independent risk marker of subsequent CD in a population of older Japanese. Methods: Among 982 adults aged 65 years or older who participated in a baseline survey, 526 cognitively intact adults (Mini-Mental State Examination [MMSE] score ≥24; mean [SD] age, 71.7 [5.6] years; women, 57.8% were followed for a period of up to 5 years. Pulse wave velocity was determined using an automated waveform analyser. Cognition was assessed by the MMSE, and CD was defined as a decrease of two points or more on the MMSE. Results: During an average follow-up of 3.4 years, 85 participants (16.2% developed CD. After controlling for important confounders, the odds ratios for CD in the highest and middle tertiles of baPWV, as compared with the lowest tertile, were 2.95 (95% confidence interval, 1.29–6.74 and 2.39 (95% confidence interval, 1.11–5.15, respectively. Conclusions: High baPWV was an independent predictor of CD in a general population of older adults and may be useful in the clinical evaluation of elders.

  20. 半导体三极管电磁脉冲损伤功率实验研究%Experimental studies on damage power of square wave electromagnetic pulse for the semiconductor triode

    Institute of Scientific and Technical Information of China (English)

    杨建光; 武占成

    2009-01-01

    针对硅微波低噪声三极管2SC3399进行方波电磁脉冲效应实验,主要研究三极管在方波电磁脉冲作用下造成损伤的损伤功率表达式,通过对损伤功率进行统计分布,发现三极管损伤能量值基本符合正态分布.%Silicon microwave low-noise triode, such as 2SC3399, has been carried on experiments of the square wave electromagnetic pulse effect. We gets some initial conclusions, and finds the expression of damage power. By the way of carrying on the statistical distribution,We find that the triode's damage energy value basically fits the normal distribution.