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Sample records for arterial switch operation

  1. Pulmonary arterial hypertension in children after neonatal arterial switch operation

    NARCIS (Netherlands)

    Zijlstra, Willemijn Mh; Elmasry, Ola; Pepplinkhuizen, Shari; Ivy, D Dunbar; Bonnet, Damien; Lévy, Marilyne; Gavilan, Jose Luis; Torrent-Vernetta, Alba; Mendoza, Alberto; Del Cerro, Maria Jesus; Moledina, Shahin; Berger, Rolf M. F.

    2017-01-01

    OBJECTIVES: Paediatric pulmonary arterial hypertension (PAH) after neonatal arterial switch operation (ASO) for transposition of the great arteries (TGA) is a clinically recognised entity with an estimated incidence of 0.6%-1.0%. Nevertheless, a clinical characterisation is lacking. We present an in

  2. The arterial switch operation in transposition of the great arteries: anatomic indications and contraindications.

    Science.gov (United States)

    Van Praagh, R; Jung, W K

    1991-12-01

    1. The arterial switch procedure is now the operation of choice for typical D-transposition of the great arteries at The Children's Hospital, Boston, USA, the operative mortality rate since 1985 being 3%. 2. There are many anatomic considerations suggesting the morphologically left ventricle (LV) may well be a better systemic pump than the morphologically right ventricle (RV) which, if true, would favor the arterial switch procedure as opposed to an atrial switch operation: (1) The LV consists almost entirely of the sinus or pumping portion, and has only a minimal distal infundibular (conal) component. The RV, by contrast, has a relatively much larger infundibular component, the primary function of which is to prevent regurgitation rather than to pump. (2) Phylogenetically, the LV is the ancient "professional" pump. By contrast, the RV is a comparatively recent modification of the bulbus cordis. (3) The LV is a two-coronary ventricle, whereas the RV is a one-coronary ventricle. (4) The LV has relatively much more compact myocardium (stratum compactum) than does the RV. (5) The mitral valve leaflets are better designed to occlude a circular systemic atrioventricular orifice than are the tricuspid valve leaflets. (6) The papillary muscles of the LV are large, paired, well balanced, and both arise from the same ventricular wall--the LV free wall. By contrast, the papillary muscles of the RV are comparatively small, numerous, unbalanced, and arise from both ventricular septal and free walls. Hence, dilatation of the LV does not pull the LV papillary muscles apart, whereas dilatation of the RV does pull the RV muscles apart, favoring the development or exacerbation of tricuspid regurgitation. (7) The LV has two conduction system radiations, whereas the RV has only one. 3. The current anatomic contraindications to the arterial switch operation in typical D-TGA include the following: (1) an unprepared LV; (2) an aortic intramural left coronary artery arising from the

  3. COMPLEX CORONARY PATTERN AFFECTING THE SURGICAL OUTCOME OF ARTERIAL SWITCH OPERATION

    Directory of Open Access Journals (Sweden)

    Amit

    2015-12-01

    Full Text Available BACKGROUND Arterial switch operation (ASO has become the procedure of choice for the transposition of great arteries as well as for Taussig-Bing anomaly. Relocation of coronary arteries remains a technical problem in anatomic correction of the transposed great arteries. The present prospective study is designed to analyse the effect of coronary artery pattern on surgical outcome of arterial switch operation. METHOD From August 2014 to November 2015, total 60 patients underwent ASO. The patients are divided in three groups. Group-A 21 patients with d-TGA with intact ventricle septum (d-TGA intact IVS, in Group-B 33 patients d-TGA with ventricular septal defect (d-TGA, VSD, and in Group C 6 Taussig Bing anomaly. The coronary pattern and outcome is analyzed. RESULTS The overall mortality related to coronary pattern was 5%. The 2 patients died due to Intramural coronary artery leading to post-operative ventricular dysfunction, another patient with single retro pulmonary coronary artery died secondary to low coronary implant leading to kinking in coronary artery and myocardial dysfunction. On 12 monthly follow up, one of the Patients in group A had right pulmonary artery stenosis with gradient of 30 mm of Hg. Another patient in group B had supravalvular gradient of 20 mm of Hg. CONCLUSION The ASO for TGA and Taussig-Bing anomaly has low early and late mortality. However, the mortality is still seen in the patients with Intramural coronary artery and in the patient with single coronary artery with retro pulmonary course.

  4. Konno procedure using atrioventricular groove patch plasty after arterial switch operation.

    Science.gov (United States)

    Kosaka, Yoshimichi; Kurosawa, Hiromi; Nagatsu, Masayoshi

    2004-11-01

    A patient with transposition of the great arteries accompanied by Shaher type 9 coronary anatomy experienced the development of progressive neoaortic valvular regurgitation with a small annulus, supravalvular stenosis, and neopulmonary valvular and supravalvular stenoses 15 years after an arterial switch operation. To implant a prosthetic valve clinically adequate in size, the Konno procedure was necessary. However, the right coronary anatomy precluded the original Konno procedure. My colleagues and I accomplished neoaortic anterior annular enlargement in this case by using atrioventricular groove patch plasty without jeopardizing the right coronary artery, and this resulted in a satisfactory outcome.

  5. Arterial mechanics at rest and during exercise in adolescents and young adults after arterial switch operation for complete transposition of the great arteries.

    Science.gov (United States)

    Chen, Robin H; Wong, Sophia J; Wong, Wilfred H; Cheung, Yiu-Fai

    2014-02-15

    We sought to determine the arterial mechanics at rest and during exercise in adolescents and young adults with complete transposition of the great arteries after arterial switch operation and their relations with neoaortic complications. Thirty patients (22 men) aged 16.2 ± 2.1 years and 22 controls (15 men) were studied. Central and peripheral arterial pulse wave velocities, carotid and radial augmentation indices, and central systolic blood pressure (cSBP) were determined by oscillometry and applanation tonometry, whereas arterial dimensions were measured by 2-dimensional echocardiography. Arterial strain, distensibility, and stiffness were determined at rest and during supine bicycle exercise testing. At rest, patients had significantly higher heart-carotid pulse wave velocity, carotid and radial augmentation indices, and cSBP than controls. At rest and during submaximal exercise, patients had significantly lower aortic strain and distensibility, greater aortic and carotid stiffness, and higher SBP than controls. Dilated aortic sinus found in 23 (76.7%) patients was associated with lower aortic distensibility, greater aortic stiffness, and higher cSBP at rest and lower aortic distensibility and strain at submaximal exercise. Significant aortic regurgitation found in 20% (6 of 30) of patients was associated with significantly higher neoaortic z scores. Multivariate analysis identified aortic stiffness at rest (β = 0.46, p = 0.003) and age at operation (β = 0.44, p = 0.004) as significant determinants of aortic sinus z scores. In conclusion, altered mechanics of the central arteries are present at rest and during exercise in adolescents and young adults after arterial switch operation. These findings may have important implications on progression of neoaortic root dilation, exercise recommendations, and medical therapy.

  6. Comparison of three dose regimens of aprotinin in infants undergoing the arterial switch operation

    Directory of Open Access Journals (Sweden)

    Verma Yashwant

    2010-01-01

    Full Text Available To determine the most effective dose regimen of aprotinin for infants undergoing arterial switch operation for transposition of the great arteries in reducing blood loss and postoperative packed red blood cell (PRBC requirements. A total of 24 infants scheduled for arterial switch operation for transposition of the great arteries were included in the study. The infants were randomly assigned to one of the three groups. Group I (n = 8 patients received aprotinin in a dose of 20,000 kallikrein inhibiting units (KIU/kg after induction of anesthesia, 20,000 KIU/kg was added to the pump prime, and 20,000 KIU/kg/hour infusion for three hours after weaning from bypass; group II (n = 8 patients received aprotinin 30,000 KIU/kg after induction of anesthesia, 30,000 KIU/kg was added to the pump prime and 30,000 KIU/Kg/hour infusion for three hours after weaning from bypass; group III patients (n = 8 received aprotinin 40,000 KIU/kg after induction of anesthesia, 40,000 KIU/kg was added to the pump prime and 40,000 KIU/kg/hour infusion for three hours after weaning from bypass. Postoperatively, the cumulative hourly blood loss and PRBC requirements were noted up to 24 hours from the time of admission in the intensive care unit (ICU. Use of blood and blood products were noted. Coagulation parameters such as hematocrit, activated clotting time (ACT, fibrinogen, prothrombin time (PT, international normalized ratio (INR, platelet count, and fibrin degradation products (FDP were investigated before cardiopulmonary bypass (CPB, after protamine administration, and at four hours postoperatively in the ICU. The number of infants reexplored for increased mediastinal drainage was recorded. Renal functions were monitored by measuring urine output (hourly and serum urea (mg% and serum creatinine (mg% at 24 hours. The sternal closure time was comparable in all the three groups. Cumulative blood loss (ml/kg/24 hours was greatest in group I (17.30 ± 7.7, least in group

  7. Lactate clearance for initiating and weaning off extracorporeal membrane oxygenation in a child with regressed left ventricle after arterial switch operation.

    Science.gov (United States)

    Singh, Sarvesh Pal; Chauhan, Sandeep; Bisoi, A K; Sahoo, Manoj

    2016-01-01

    We hereby report a child with transposition of great arteries and regressed ventricle who underwent arterial switch operation (ASO) with the aid of cardiopulmonary bypass and "integrated" extracorporeal membrane oxygenation (ECMO) circuit. The significance of lactate clearance as a guide to initiate and terminate veno-arterial ECMO in a post ASO child with regressed left ventricle is discussed.

  8. Lactate clearance for initiating and weaning off extracorporeal membrane oxygenation in a child with regressed left ventricle after arterial switch operation

    Directory of Open Access Journals (Sweden)

    Sarvesh Pal Singh

    2016-01-01

    Full Text Available We hereby report a child with transposition of great arteries and regressed ventricle who underwent arterial switch operation (ASO with the aid of cardiopulmonary bypass and "integrated" extracorporeal membrane oxygenation (ECMO circuit. The significance of lactate clearance as a guide to initiate and terminate veno-arterial ECMO in a post ASO child with regressed left ventricle is discussed.

  9. Evaluation of cardiac autonomic nerves by iodine-123 metaiodobenzylguanidine scintigraphy and ambulatory electrocardiography in patients after arterial switch operations

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, Hajime; Maeda, Masanobu; Miyahara, Ken [Shakaihoken Chukyo Hospital, Nagoya (Japan)] [and others

    2000-05-01

    The autonomic cardiac nerves reach the heart after passing through the vicinity of the aortic root and the pulmonary trunk. The arterial switch operation (ASO) completely transects the ascending aorta and the pulmonary trunk. Therefore, this surgical procedure virtually denerves the heart. Cardiac sympathetic denervation and reinnervation were evaluated in patients after ASO using iodine-123 metaiodobenzylguanidine (MIBG) myocardial scintigraphy and parasympathetic denervation and reinnervation using ambulatory electrocardiography [Holter electrocardiogram (ECG)]. MIBG scintigraphy was performed in 14 patients who underwent ASO (ASO group) and 3 patients who underwent other open heart surgery (control group). All patients in the ASO group underwent the operation in the neonatal or infantile period. Planar and single photon emission computed tomography (SPECT) images of the myocardium were obtained. Defect score was determined by the SPECT images as a semi-quantitative index. The mean interval between ASO and MIBG scintigraphy was 25.6{+-}14.6 months. Holter ECG was also performed in 14 patients in the ASO group and 19 age-matched normal children. The Holter ECGs were plotted on a Lorenz plot. The H index, which is related to vagal tone for the cardiovascular system, was calculated from the R-R intervals. The mean interval between the ASO and Holter ECG was 8.3{+-}9.7 months. MIBG scintigraphy in the control group demonstrated an almost normal homogeneous tracer uptake, but showed extremely reduced tracer uptake and significantly higher defect score in the ASO group. The extent and degree of the reduction of MIBG uptake improved with time after the ASO. The heart-to-mediastinum MIBG count ratio tended to increase with time. The H index of the ASO group was lower than that of normal children (<12 months: Control group 0.0280{+-}0.0068 vs ASO group 0.0219{+-}0.0083), and gradually increased with time (1-3 years: 0.0470{+-}0.0157 vs 0.0314{+-}0.0124). (author)

  10. Comparative analysis of early and middle outcomes of the arterial switch operation in children with complete transposition of the great arteries with ventricular septal defect and severe pulmonary artery hypertension

    Institute of Scientific and Technical Information of China (English)

    LIU Cheng-hu; SU Jun-wu; LI Zhi-qiang; FAN Xiang-ming; CHEN Yan; HE Yan; LIU Ying-long

    2013-01-01

    Background The best age for the arterial switch operation (ASO) in complete transposition of great arteries with ventricular septal defect is usually considered to be within six months.This is because of severe pulmonary arterial hypertension and pulmonary arterial obstructive pathological changes.There are few reports on ASO surgery in children older than three years old.Methods We studied 41 children,including 24 males and 17 females,from January 2010 to December 2011.They were divided into three groups by operation age; 15 patients were <1 year old,13 were 1-3 years old,and 13 were >3 years old.Associated cardiac abnormalities included patent ductus arteriosus in six cases,atrial septal defect in five cases,and mitral regurgitation in two cases.All the patients had echocardiography before the operation.Seventeen patients underwent a coronary computed tomography examination and five patients underwent right heart catheterization.All ASO surgeries were performed under inhalation anesthesia and hypothermic cardiopulmonary bypass.Results Three operative deaths occurred.Two were in the <1 year old group,who died from severe postoperative low cardiac output.The other was two years old and died of postoperative multiple organ failure.There was no significant difference in postoperative mortality and the recent mid-term survival rate among the three groups.Thirty-eight cases were followed up for an average of 11.2 months,ranging 6-20 months.One seven years old patient died of acute diarrhea and electrolyte disturbance arrhythmia caused by food poisoning.Three patients more than three years old still had residual pulmonary arterial hypertension.Conclusion Children older than three years old can still undergo the ASO procedure,but residual pulmonary hypertension is present.

  11. Left Ventricular Function after Arterial Switch Operation as Assessed by Two-Dimensional Speckle-Tracking Echocardiography in Patients with Simple Transposition of the Great Arteries

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    Elaheh Malakan Rad

    2016-11-01

    Full Text Available Background: The late postoperative course for children with transposition of the great arteries (TGA with an intact ventricular septum (IVS is very important because the coronary arteries may be at risk of damage during arterial switch operation (ASO. We sought to investigate left ventricular function in patients with TGA/IVS by echocardiography.Methods: From March 2011 to December 2012, totally 20 infants (12 males and 8 females with TGA/IVS were evaluated via 2-dimensional speckle-tracking echocardiography (2D STE more than 6 months after they underwent ASO. A control group of age-matched infants and children was also studied. Left ventricular longitudinal strain (S, strain rate (SR, time to peak systolic longitudinal strain (TPS, and time to peak systolic longitudinal strain rate (TPSR were measured and compared between the 2 groups.Results: Mean ± SD of age at the time of study in the patients with TGA/IVS was 15 ± 5 months, and also age at the time of ASO was 12 ± 3 days. Weight was 3.13 ± 0.07 kg at birth and 8.83 ± 1.57 kg at the time of ASO. Global strain (S, Time to peak strain rate (TPSR, and Time to peak strain (TPS were not significantly different between the 2 groups, whereas global strain rate (SR was significantly different (p value < 0.001.  In the 3-chamber view, the values of S in the lateral, septal, inferior, and anteroseptal walls were significantly different between the 2 groups (p value < 0.001, and SR in the posterior wall was significantly different between the 2 groups (p value < 0.001. There were no positive correlations between S and SR in terms of the variables of heart rate, total cardiopulmonary bypass time, and aortic cross-clamp time. There were no statistically significant differences between the 2 groups regarding S, SR, TPS, and TPSR in the anteroseptal and posterior walls in the 3-chamber view and in the lateral and septal walls in the 4-chamber view. Conclusion: We showed that between 6 and 18 months

  12. Arterial switch operation in children over 6 months%6月龄以上患儿大动脉调转手术效果分析

    Institute of Scientific and Technical Information of China (English)

    王显悦; 毕生辉; 王晓武; 董文鹏; 徐宇; 梅鲁刚; 梁爱琼; 张卫达

    2013-01-01

    Objective:To investigate effects of arterial switch operation (ASO) in children over 6 months.Method:From June 2009 to July 2012,children scheduled for ASO) were divided into A group (<6 months,n=24) and B group (≥6 months,n =18),and ASO performed after preoperative treatments and examinations.Effects of ASO,3 months follow up echocardiography and complications were observed.The records about ASOfrom two groups were compared in terms of operating time,cardiopulmonary bypass time,cardiac arrest time and automatic cardioversion in operation.Circulation function records from two groups such as mean pulmonary artery pressure (MPAP),mean arterial pressure (MAP) and central venous pressure (CVP) right after blood ultrafiltration,inotropic scores at ICU were made contrasts.The change of MPAP before and after operation in two groups were observed.The records in ICU were compared included ICU time,ventilation time,frequency of re-intubation and pulmonary infection.Result:Two infants died in the first day after operation in group A,the others were clinically cured,and 12 cases had contented follow-up echocardiography examinations 3 months later and had no complications.Sudden death accurred to 1 case in group B in hospital,other children were clinically cured,7 cases had satisfactory echocardiography and complications follow-up 3 months later,and 1 case suffered sudden death at home.There was no statistical difference between two groups as to operating time,cardiopulmonary bypass time,cardiac arrest time and automatic cardioversion in operation.MAP in two groups right after blood ultrafiltration in operation had no statistical difference.MPAP in two groups descended obviously after operation (P<0.05).Compared with group A,children in group B had higher MPAP,CVP right separation from modified ultrafiltration,higher inotropic scores at ICU,longer ICU time and ventilation time,higher frequency of re-intubation and pulmonary infection postoperation (all P<0

  13. Fault tolerant operation of switched reluctance machine

    Science.gov (United States)

    Wang, Wei

    The energy crisis and environmental challenges have driven industry towards more energy efficient solutions. With nearly 60% of electricity consumed by various electric machines in industry sector, advancement in the efficiency of the electric drive system is of vital importance. Adjustable speed drive system (ASDS) provides excellent speed regulation and dynamic performance as well as dramatically improved system efficiency compared with conventional motors without electronics drives. Industry has witnessed tremendous grow in ASDS applications not only as a driving force but also as an electric auxiliary system for replacing bulky and low efficiency auxiliary hydraulic and mechanical systems. With the vast penetration of ASDS, its fault tolerant operation capability is more widely recognized as an important feature of drive performance especially for aerospace, automotive applications and other industrial drive applications demanding high reliability. The Switched Reluctance Machine (SRM), a low cost, highly reliable electric machine with fault tolerant operation capability, has drawn substantial attention in the past three decades. Nevertheless, SRM is not free of fault. Certain faults such as converter faults, sensor faults, winding shorts, eccentricity and position sensor faults are commonly shared among all ASDS. In this dissertation, a thorough understanding of various faults and their influence on transient and steady state performance of SRM is developed via simulation and experimental study, providing necessary knowledge for fault detection and post fault management. Lumped parameter models are established for fast real time simulation and drive control. Based on the behavior of the faults, a fault detection scheme is developed for the purpose of fast and reliable fault diagnosis. In order to improve the SRM power and torque capacity under faults, the maximum torque per ampere excitation are conceptualized and validated through theoretical analysis and

  14. Organolead Halide Perovskites for Low Operating Voltage Multilevel Resistive Switching.

    Science.gov (United States)

    Choi, Jaeho; Park, Sunghak; Lee, Joohee; Hong, Kootak; Kim, Do-Hong; Moon, Cheon Woo; Park, Gyeong Do; Suh, Junmin; Hwang, Jinyeon; Kim, Soo Young; Jung, Hyun Suk; Park, Nam-Gyu; Han, Seungwu; Nam, Ki Tae; Jang, Ho Won

    2016-08-01

    Organolead halide perovskites are used for low-operating-voltage multilevel resistive switching. Ag/CH3 NH3 PbI3 /Pt cells exhibit electroforming-free resistive switching at an electric field of 3.25 × 10(3) V cm(-1) for four distinguishable ON-state resistance levels. The migration of iodine interstitials and vacancies with low activation energies is responsible for the low-electric-field resistive switching via filament formation and annihilation.

  15. Compact SCR trigger circuit for ignitron switch operates efficiently

    Science.gov (United States)

    Foster, L. E.

    1965-01-01

    Trigger circuit with two series-connected SCR triggers an ignitron switch used to discharge high-energy capacitor banks. It does not require a warmup period and operates at relatively high efficiency.

  16. Arterial gas occlusions in operating heat pipes

    Science.gov (United States)

    Saaski, E. W.

    1975-01-01

    The effect of noncondensable gases on high performance arterial heat pipes has been investigated both analytically and experimentally. Models have been generated which characterize the dissolution of gases in condensate and the diffusional loss of dissolved gases from condensate in arterial flow. These processes, and others, have been used to postulate stability criteria for arterial heat pipes. Experimental observations of gas occlusions were made using a stainless steel heat pipe equipped with viewing ports, and the working fluids methanol and ammonia with the gas additives helium, argon, and xenon. Observations were related to gas transport models.

  17. Blood Pressure Control in Smokers with Arterial Hypertension Who Switched to Electronic Cigarettes

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    Riccardo Polosa

    2016-11-01

    Full Text Available Electronic cigarettes (ECs are battery-operated devices designed to vaporise nicotine, which may help smokers with quitting or reducing their tobacco consumption. No data is available regarding the health effects of ECs use among smokers with arterial hypertension and whether regular use results in blood pressure (BP changes. We investigated long-term changes in resting BP and level of BP control in hypertensive smokers who quit or reduced substantially their tobacco consumption by switching to ECs. A medical records review of patients with hypertension was conducted to identify patients reporting regular daily use of ECs on at least two consecutive follow-up visits. Regularly smoking hypertensive patients were included as a reference group. A marked reduction in cigarette consumption was observed in ECs users (n = 43 though consumption remained unchanged in the control group (n = 46. Compared to baseline, at 12 months (follow-up visit 2 decline in cigarette consumption was associated with significant reductions in median (25th-, 75th-centile systolic BP (140 (134.5, 144 to 130 (123.5, 138.5 mmHg; p < 0.001 and diastolic BP (86 (78, 90 to 80 (74.5, 90 mmHg; p = 0.006. No significant changes were observed in the control group. As expected, decline in cigarette consumption in the ECs users was also associated with improved BP control. The study concludes that regular ECs use may aid smokers with arterial hypertension reduce or abstain from cigarette smoking, with only trivial post-cessation weight gain. This resulted in improvements in systolic and diastolic BP as well as better BP control.

  18. Blood Pressure Control in Smokers with Arterial Hypertension Who Switched to Electronic Cigarettes

    Science.gov (United States)

    Polosa, Riccardo; Morjaria, Jaymin B.; Caponnetto, Pasquale; Battaglia, Eliana; Russo, Cristina; Ciampi, Claudio; Adams, George; Bruno, Cosimo M.

    2016-01-01

    Electronic cigarettes (ECs) are battery-operated devices designed to vaporise nicotine, which may help smokers with quitting or reducing their tobacco consumption. No data is available regarding the health effects of ECs use among smokers with arterial hypertension and whether regular use results in blood pressure (BP) changes. We investigated long-term changes in resting BP and level of BP control in hypertensive smokers who quit or reduced substantially their tobacco consumption by switching to ECs. A medical records review of patients with hypertension was conducted to identify patients reporting regular daily use of ECs on at least two consecutive follow-up visits. Regularly smoking hypertensive patients were included as a reference group. A marked reduction in cigarette consumption was observed in ECs users (n = 43) though consumption remained unchanged in the control group (n = 46). Compared to baseline, at 12 months (follow-up visit 2) decline in cigarette consumption was associated with significant reductions in median (25th-, 75th-centile) systolic BP (140 (134.5, 144) to 130 (123.5, 138.5) mmHg; p < 0.001) and diastolic BP (86 (78, 90) to 80 (74.5, 90) mmHg; p = 0.006). No significant changes were observed in the control group. As expected, decline in cigarette consumption in the ECs users was also associated with improved BP control. The study concludes that regular ECs use may aid smokers with arterial hypertension reduce or abstain from cigarette smoking, with only trivial post-cessation weight gain. This resulted in improvements in systolic and diastolic BP as well as better BP control. PMID:27845734

  19. Memristive operations demonstrated by gap-type atomic switches

    Science.gov (United States)

    Hasegawa, Tsuyoshi; Nayak, Alpana; Ohno, Takeo; Terabe, Kazuya; Tsuruoka, Tohru; Gimzewski, James K.; Aono, Masakazu

    2011-03-01

    We demonstrate memristive operations using gap-type Ag2S atomic switches, in which the growth and shrinkage of an Ag protrusion are controlled by using solid-electrochemical reactions. In addition to conventional memristive operations such as those proposed and demonstrated by resistive random-access memories (ReRAMs) using metal oxide compounds, gap-type Ag2S atomic switches also show new types of memristive operations by storing information from input signals without changing their output until a sufficient number of signals are inputted. The new types of memristive operations resemble the learning process seen in neuroplasticity, where changes occur in the organization of the human brain as a result of experience.

  20. Transistor electronics use of semiconductor components in switching operations

    CERN Document Server

    Rumpf, Karl-Heinz

    2014-01-01

    Transistor Electronics: Use of Semiconductor Components in Switching Operations presents the semiconductor components as well as their elementary circuits. This book discusses the scope of application of electronic devices to increase productivity. Organized into eight chapters, this book begins with an overview of the general equation for the representation of integer positive numbers. This text then examines the properties and characteristics of basic electronic components, which relates to an understanding of the operation of semiconductors. Other chapters consider the electronic circuit ar

  1. [Psychoprophylaxis in patients after coronary artery bypass graft operations].

    Science.gov (United States)

    Rymaszewska, Joanna; Chładzińska-Kiejna, Sylwia; Górna, Renata; Kustrzycki, Wojciech

    2004-05-01

    The paper presented problems of quality of life and psychosocial functioning of patients following coronary artery bypass grafting operations. Possibilities of psychoprophylactic effects towards these patients and its efficacy were described.

  2. 49 CFR 236.202 - Signal governing movements over hand-operated switch.

    Science.gov (United States)

    2010-10-01

    ... switch. 236.202 Section 236.202 Transportation Other Regulations Relating to Transportation (Continued...-operated switch. Signal governing movements over hand-operated switch in the facing direction shall display... over the switch in the normal and in the reverse position, the signal shall display its...

  3. 49 CFR 236.207 - Electric lock on hand-operated switch; control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Electric lock on hand-operated switch; control... switch; control. Electric lock on hand-operated switch shall be controlled so that it cannot be unlocked until control circuits of signals governing movements over such switch have been opened. Approach...

  4. Optically controlled multiple switching operations of DNA biopolymer devices

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Chao-You; Tu, Waan-Ting; Lin, Yi-Tzu [Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Fruk, Ljiljana [Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Hung, Yu-Chueh, E-mail: ychung@ee.nthu.edu.tw [Institute of Photonics Technologies, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2015-12-21

    We present optically tunable operations of deoxyribonucleic acid (DNA) biopolymer devices, where a single high-resistance state, write-once read-many-times memory state, write-read-erase memory state, and single low-resistance state can be achieved by controlling UV irradiation time. The device is a simple sandwich structure with a spin-coated DNA biopolymer layer sandwiched by two electrodes. Upon irradiation, the electrical properties of the device are adjusted owing to a phototriggered synthesis of silver nanoparticles in DNA biopolymer, giving rise to multiple switching scenarios. This technique, distinct from the strategy of doping of pre-formed nanoparticles, enables a post-film fabrication process for achieving optically controlled memory device operations, which provides a more versatile platform to fabricate organic memory and optoelectronic devices.

  5. Fabric heart retractor for coronary artery bypass operations.

    Science.gov (United States)

    Kazama, S; Ishihara, A

    1993-06-01

    A new device for heart retraction during coronary artery bypass operations has been developed. It provides safe and steady support and an unobstructed view of the lateral, posterior, and inferior surfaces of the heart; in addition, it is easy to handle.

  6. Electrically operated magnetic switch designed to display reduced leakage inductance

    Science.gov (United States)

    Cook, Edward G.

    1994-01-01

    An electrically operated magnetic switch is disclosed herein for use in opening and closing a circuit between two terminals depending upon the voltage across these terminals. The switch so disclosed is comprised of a ferrite core in the shape of a toroid having opposing ends and opposite inner and outer sides and an arrangement of electrically conductive components defining at least one current flow path which makes a number of turns around the core. This arrangement of components includes a first plurality of electrically conducive rigid rods parallel with and located outside the outer side of the core and a second plurality of electrically conductive rigid rods parallel with and located inside the inner side of the core. The arrangement also includes means for electrically connecting these rods together so that the define the current flow path. In one embodiment, this latter means uses rigid cross-tab means. In another, preferred embodiment, printed circuits on rigid dielectric substrates located on opposite ends of the core are utilized to interconnect the rods together.

  7. The effects of mobile ATM switches on PNNI peer group operation

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, L.; Sholander, P.; Tolendino, L.

    1997-04-01

    This contribution discusses why, and how, mobile networks and mobile switches might be discussed during Phase 1 of the WATM standards process. Next, it reviews mobile routers within Mobile IP. That IP mobility architecture may not apply to the proposed mobile ATM switches. Finally, it discusses problems with PNNI peer group formation and operation when mobile ATM switches are present.

  8. Analysis of bi-directional piezoelectric-based converters for zero-voltage switching operation

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Zhang, Zhe; Andersen, Michael A. E.

    2016-01-01

    This paper deals with a thorough analysis of zerovoltage switching especially for bi-directional, inductorless, piezoelectric transformer-based switch-mode power supplies with a half-bridge topology. Practically, obtaining zero-voltage switching for all of the switches in a bi......-directional piezoelectric power converter is a difficult task. However, the analysis in this work will be convenient for overcoming this challenge. The analysis defines the zero-voltage region indicating the operating points whether or not soft switching can be met over the switching frequency and load range. For the first...... time, a comprehensive analysis is provided, which can be used as a design guideline for applying control techniques in order to drive switches in piezoelectric transformer-based converters. This study further conveys the proposed method to the region where all the switches can obtain soft switching...

  9. [The possibilities for the transcranial monitoring of the blood flow in the circle of Willis arteries during operations on the brachiocephalic arteries and in heart operations].

    Science.gov (United States)

    Kuntsevich, G I; Kaĭdash, A N; Ter-Khachaturova, I E; Kovalevskaia, O A

    1995-01-01

    The paper gives the results of arterial blood flow monitoring in the circle of Willis via transcranial Doppler during 81 reparative operations on brachiocephalic arteries (including carotid endarterectomy from the internal carotid artery in 32 patients). Transcranial monitoring of blood flow supports the fact that there is a collateral reflow along the cerebral arteries during removal of the common carotid artery and that there is a relationship between the status of great arteries and arteries of Willis' circle. The paper also summaries the results of a comprehensive ultrasound study of 9 patients who have undergone reparative and plastic operations on the cardiac valves during extracorporeal circulation and general hypothermia. Blood flow was intraoperatively monitored in the arteries of the basis cerebri by using transcranial duplex scanning with colour Doppler flow mapping to evaluate not only hemodynamics, but also the embolic situation, as well as to check up how air was removed from the cardiac cavities by transesophageal echocardiography.

  10. 大动脉调转术后儿童母亲亲职压力和心理状态的对照研究%Case-control study in parenting stress and mental state in mothers of children after arterial switch operation

    Institute of Scientific and Technical Information of China (English)

    曾小璐; 邹小兵; 岑超群; 钟敏泉

    2011-01-01

    [目的]探讨大动脉调转术后儿童与正常儿童母亲的亲职压力和心理状况,为术后儿童的全面康复提供数据. [方法]采用亲职压力指标简表(Parenting Stress Index Short Form,PSI/SF)、状态-特质焦虑量表(State-Trait Anxiety InventorY,STAI)对135例大动脉调转术后儿童的母亲和142例正常儿童的母亲进行调查. [结果]大动脉调转术后儿童的母亲亲职压力量表总分、亲职愁苦及亲子互动失调分量表得分高于正常对照组[总分(93.49±15.10)vs(74.71±16.55),P<0.05],状态焦虑得分高于正常对照组[(43.19±7.07)vs(39.67±7.45),P<0.053,亲职压力量表总分及亲职愁苦分量表得分与状态焦虑得分呈正相关. [结论]大动脉调转术后儿童母亲存在较高水平的亲职压力和状态焦虑,值得专业人员关注和实施干预.%[Objective] To explore parenting stress and mental state in mothers of children after arterial switch operation(ASO)and children with normal development,presenting information for comprehensive rehabilitation of children accepting operation in infancy. [Methods] A total of 135 mothers of children who undergone ASO were investigated with the Parenting Stress Index Short Form (PSI / SF), State-Trait Anxiety Inventory(STAI). Their scores were compared with that of 142 mothers with healthy children. [Results] Mothers of children after ASO exprienced a significantly higher level in the total score of parenting stress and subscale score of parental distress and parent-child dysfunctional interaction as compared with mothers of healthy children[ the total score(93. 49 ± 15. 10) vs(74. 71 ± 16.55), P< 0.05 ]. In terms of the STAI, we found mothers of children after ASO) have higher SAI scores[ (43. 19± 7. 07)vs(39.67 ±7. 45 ), P< 0. 05 ] which were correlated with total parenting stress and parental distress. [Conclusions] Mothers of children undergone ASO generally experience more parenting stress and state anxiety than

  11. A Compact Thermal Heat Switch for Cryogenic Space Applications Operating near 100 K

    CERN Document Server

    Dietrich, Marc; Thummes, Günter

    2013-01-01

    A thermal heat switch has been developed intended for cryogenic space applications operating around 100 K. The switch was designed to separate two pulse tube cold heads that cool a common focal plane array. Two cold heads are used for redundancy reasons, while the switch is used to reduce the thermal heat loss of the stand-by cold head, thus limiting the required input power, weight and dimensions of the cooler assembly. After initial evaluation of possible switching technologies, a construction based on the thermal expansion coefficient (CTE) of different materials was chosen. A simple design is proposed based on thermoplasts which have one of the highest CTE known permitting a relative large gap width in the open state. Furthermore, the switch requires no power neither during normal operation nor for switching. This enhances reliability and allows for a simple mechanical design. After a single switch was successfully built, a second doubleswitch configuration was designed and tested. The long term performan...

  12. The operational mechanism of ferroelectric-driven organic resistive switches

    NARCIS (Netherlands)

    Kemerink, M.; Asadi, K.; Blom, P.W.M.; Leeuw, D.M. de

    2012-01-01

    The availability of a reliable memory element is crucial for the fabrication of 'plastic' logic circuits. We use numerical simulations to show that the switching mechanism of ferroelectric-driven organic resistive switches is the stray field of the polarized ferroelectric phase. The stray field modu

  13. Observations and implications of gap closure in plasma opening switch operation

    Science.gov (United States)

    Goyer, John R.; Kortbawi, David

    1994-09-01

    Plasma opening switches are believed to develop voltage through opening and magnetically insulating a gap formed in plasma injected between two conducting electrodes. Data will be presented to show that a relatively simple assumption about the behavior of this gap suffices to describe the overall operation of the switch. Specifically, the observed increase, then decrease, of operational voltage as a function of conduction time can be accounted for by the switch gap linearly decreasing with conduction time, while the conducted current increases. In addition to presentation of data to demonstrate this collapse, analysis is performed to couple the gap history to the voltage predicted for the switch, and to optimize this latter quantity.

  14. An Easily Operating Polymer 1×4 Optical Waveguide Switch Matrix Based on Vertical Couplers

    Institute of Scientific and Technical Information of China (English)

    Kaixin Chen; Pak L Chu; Hau Ping Chan; Kin S. Chiang

    2007-01-01

    A three-dimensional (3D) polymer thermo-optic (TO) 1×4 waveguide switch matrix based on vertical couplers is demonstrated. It consists of four basic 3D switch units and because of its 3D structure, its construction is compact, only 9mm in length; moreover, the control logic of the entire switch is very simple, the light signal can be easily switched to any output port by operating only a single switch unit. The finished devices exhibit a switching extinction ratio greater than 21 dB for all of four output ports and the crosstalk between two adjacent output ports is lower than n for all switching units is about 50 mW.

  15. Effect of Surgical Time on Outcomes Following Primary Arterial Switch Operation in Children with Transposition of Great Arteries%大动脉调转术手术时机对完全性大动脉转位患儿预后的影响

    Institute of Scientific and Technical Information of China (English)

    孙新; 何少茹; 庄建; 陈寄梅; 郑曼利; 刘玉梅; 孙云霞; 梁穗新; 张程

    2011-01-01

    Objective To investigate the effect of surgical time on outcomes following primary ASO in children with transposition of great arteries (TGA). Methods Sixty - four infantile patients diagnosed as TGA had primary ASO from Jan. 2008 to Dec. 2009. They were divided into 2 groups,36 with intact ventricular septum(IVS) and 28 with ventricular septal defect(VSD). Each group was further divided into 2 subgroups( early group and late group)with a boundary of surgical age of 14 days and 28 days separately. The perioperative complications and mortality of 2 subgroups in each group and follow up of the discharged patients were analyzed retrospectively. Results There were no significant differences between the 2 subgroups in each group in postoperative complications such as pulmonary stenosis, low cardiac output syndrome, bleeding of the incision, faulty union of the incision, diaphragmatic paralysis, airway abnormalities, arrhythmia and pulmonary infection.Three cases occurred hospital deaths and there was no significant difference of the hospital mortality between 2 subgroups in TGA/IVS group ( 8.3 % vs 0, P > 0. 05 ) and TGA/VSD group ( 0 υs 7.7 % , P > 0. 05). With a median follow - up of 13 months,2 cases of late deaths occured and there was no statistical difference of early mortalities between the 2 subgroups in TGA/IVS group ( 10.5% vs 10. 0%, P > 0.05 ) and TGA/VSD group (0 vs 22.2%, P > 0.05 ). Conclusions Preoperative conditions, preterm, infection and follow - up in time rather than age are important factors affecting postoperative outcomes of patients with primary ASO. Improving preoperative conditions and intensifying follow - up will improve postoperative outcomes.%目的 评价大动脉调转术(ASO)手术时机对完全性大动脉转位患儿预后的影响.方法 2008年1月-2009年12月共64例完全性大动脉转位(TGA)患儿在本院行一期ASO,其中36例室间隔完整(IVS),28例并室间隔缺损(VSD).各组依手

  16. A fast operating magnetically controlled switch for 1 kA

    NARCIS (Netherlands)

    Mulder, G.B.J.; Kate, ten H.H.J.; Nijhuis, A.; Klundert, van de L.J.M.

    1985-01-01

    The power of fully superconducting rectifiers can be improved by increasing either the operating frequency or the transformer primary inductance [1]. The frequency is usually limited by the recovery time of thermally controlled switches. In order to achieve a higher switching speed, magnetically con

  17. Double-tunnel nanoscale switch with a redox mediator: Operational principles and tunneling spectroscopy

    DEFF Research Database (Denmark)

    Kornyshev, AA; Kumetsov, AM; Ulstrup, Jens

    2005-01-01

    A description of the physical mechanism and operation of a navel nanometric electronic switch [D.I. Gittins et al., Nature 2000 408, 67] is presented. New options for controlling the properties of this device are suggested and analyzed....

  18. Direct energy converter controllers for switched reluctance motor operation

    OpenAIRE

    Goodman, Andrew Simon

    2007-01-01

    There is increasing demand for simple motor drives offering high reliability and fault tolerance in applications such as the aerospace actuator industry, with the development of `more electric aircraft'. This thesis presents a motor drive employing a switched reluctance motor, the novel single sided matrix converter, and a novel double band hysteresis based control scheme for control of the converter, implemented using a field programmable gate array (FPGA). The single sided matrix co...

  19. Transposition of Great Arteries with Intramural Coronary Artery: Experience with a Modified Surgical Technique

    Directory of Open Access Journals (Sweden)

    Amit Mishra

    2016-02-01

    Full Text Available Abstract Objective: Transposition of the great arteries is a common congenital heart disease. Arterial switch is the gold standard operation for this complex heart disease. Arterial switch operation in the presence of intramural coronary artery is surgically the most demanding even for the most experienced hands. We are presenting our experience with a modified technique for intramural coronary arteries in arterial switch operation. Methods: This prospective study involves 450 patients undergoing arterial switch operation at our institute from April 2006 to December 2013 (7.6 years. Eighteen patients underwent arterial switch operation with intramural coronary artery. The coronary patterns and technique used are detailed in the text. Results: The overall mortality found in the subgroup of 18 patients having intramural coronary artery was 16% (n=3. Our first patient had an accidental injury to the left coronary artery and died in the operating room. A seven-day old newborn died from intractable ventricular arrhythmia fifteen hours after surgery. Another patient who had multiple ventricular septal defects with type B arch interruption died from residual apical ventricular septal defect and sepsis on the eleventh postoperative day. The remainder of the patients are doing well, showing a median follow-up duration of 1235.34±815.26 days (range 369 - 2730. Conclusion: Transposition of the great arteries with intramural coronary artery is demanding in a subset of patients undergoing arterial switch operation. We believe our technique of coronary button dissection in the presence of intramural coronary arteries using coronary shunt is simple and can be a good addition to the surgeons' armamentarium.

  20. Transposition of Great Arteries with Intramural Coronary Artery: Experience with a Modified Surgical Technique

    Science.gov (United States)

    Mishra, Amit; Jain, Anil; Hinduja, Manish; Wadhawa, Vivek; Patel, Ramesh; Vaidhya, Nikunj; Rodricks, Dayesh; Patel, Hardik

    2016-01-01

    Objective: Transposition of the great arteries is a common congenital heart disease. Arterial switch is the gold standard operation for this complex heart disease. Arterial switch operation in the presence of intramural coronary artery is surgically the most demanding even for the most experienced hands. We are presenting our experience with a modified technique for intramural coronary arteries in arterial switch operation. Methods: This prospective study involves 450 patients undergoing arterial switch operation at our institute from April 2006 to December 2013 (7.6 years). Eighteen patients underwent arterial switch operation with intramural coronary artery. The coronary patterns and technique used are detailed in the text. Results: The overall mortality found in the subgroup of 18 patients having intramural coronary artery was 16% (n=3). Our first patient had an accidental injury to the left coronary artery and died in the operating room. A seven-day old newborn died from intractable ventricular arrhythmia fifteen hours after surgery. Another patient who had multiple ventricular septal defects with type B arch interruption died from residual apical ventricular septal defect and sepsis on the eleventh postoperative day. The remainder of the patients are doing well, showing a median follow-up duration of 1235.34±815.26 days (range 369 - 2730). Conclusion: Transposition of the great arteries with intramural coronary artery is demanding in a subset of patients undergoing arterial switch operation. We believe our technique of coronary button dissection in the presence of intramural coronary arteries using coronary shunt is simple and can be a good addition to the surgeons' armamentarium. PMID:27074270

  1. AIR ATMOSPHERIC-PRESSURE DISCHARGERS FOR OPERATION IN HIGH-FREQUENCY SWITCHING MODE.

    Directory of Open Access Journals (Sweden)

    L.S. Yevdoshenko

    2013-10-01

    Full Text Available Operation of two designs of compact multigap dischargers has been investigated in a high-frequency switching mode. It is experimentally revealed that the rational length of single discharge gaps in the designs is 0.3 mm, and the maximum switching frequency is 27000 discharges per second under long-term stable operation of the dischargers. It is shown that in pulsed corona discharge reactors, the pulse front sharpening results in increasing the operating electric field strength by 1.3 – 1.8 times.

  2. 75 FR 7305 - Drake Switching Company, LLC-Operation Exemption- Drake Cement, LLC

    Science.gov (United States)

    2010-02-18

    ... Surface Transportation Board Drake Switching Company, LLC--Operation Exemption-- Drake Cement, LLC Drake... facilities to be owned and operated by Drake Cement, LLC.\\1\\ \\1\\ Drake Cement, LLC filed a verified notice of exemption to acquire these track in STB Finance Docket No. 35350, Drake Cement, LLC--Acquisition...

  3. Internal iliac artery embolisation for intractable bladder haemorrhage in the peri-operative phase

    Science.gov (United States)

    Gujral, S.; Bell, R.; Kabala, J.; Persad, R.

    1999-01-01

    Intractable haemorrhage from the bladder wall during transurethral resection of bladder tumour is uncommon but potentially catastrophic. Internal iliac artery embolisation is a minimally invasive technique, which is now widely practised to stop bleeding from branches of these arteries in situations including pelvic malignancy, obstetric and gynaecological emergencies and trauma. We report its successful use peri-operatively, in an unfit, elderly patient with uncontrolled bleeding.


Keywords: embolisation; internal iliac artery; transurethral resection of bladder tumour PMID:10448498

  4. Many-body decoherence dynamics and optimized operation of a single-photon switch

    Science.gov (United States)

    Murray, C. R.; Gorshkov, A. V.; Pohl, T.

    2016-09-01

    We develop a theoretical framework to characterize the decoherence dynamics due to multi-photon scattering in an all-optical switch based on Rydberg atom induced nonlinearities. By incorporating the knowledge of this decoherence process into optimal photon storage and retrieval strategies, we establish optimized switching protocols for experimentally relevant conditions, and evaluate the corresponding limits in the achievable fidelities. Based on these results we work out a simplified description that reproduces recent experiments (Nat. Commun. 7 12480) and provides a new interpretation in terms of many-body decoherence involving multiple incident photons and multiple gate excitations forming the switch. Aside from offering insights into the operational capacity of realistic photon switching capabilities, our work provides a complete description of spin wave decoherence in a Rydberg quantum optics setting, and has immediate relevance to a number of further applications employing photon storage in Rydberg media.

  5. On the Characterization of Hankel and Toeplitz Operators Describing Switched Linear Dynamic Systems with Point Delays

    Directory of Open Access Journals (Sweden)

    M. De la Sen

    2009-01-01

    are given to define pointwisely the causal and anticausal Toeplitz and Hankel operators from the set of switching time instants generated from the switching function. The case of the auxiliary unforced system defined by the matrix of undelayed dynamics being dichotomic (i.e., it has no eigenvalue on the complex imaginary axis is considered in detail. Stability conditions as well as dual instability ones are discussed for this case which guarantee that the whole system is either stable, or unstable but no configuration of the switched system has eigenvalues within some vertical strip including the imaginary axis. It is proved that if the system is causal and uniformly controllable and observable, then it is globally asymptotically Lyapunov stable independent of the delays, that is, for any possibly values of such delays, provided that a minimum residence time in-between consecutive switches is kept or if all the set of matrices describing the auxiliary unforced delay—free system parameterizations commute pairwise.

  6. Many-body decoherence dynamics and optimised operation of a single-photon switch

    CERN Document Server

    Murray, Callum R; Pohl, Thomas

    2016-01-01

    We develop a theoretical framework to characterize the decoherence dynamics due to multi-photon scattering in an all-optical switch based on Rydberg atom induced nonlinearities. By incorporating the knowledge of this decoherence process into optimal photon storage and retrieval strategies, we establish optimised switching protocols for experimentally relevant conditions, and evaluate the corresponding limits in the achievable fidelities. Based on these results we work out a simplified description that reproduces recent experiments [arXiv:1511.09445] and provides a new interpretation in terms of many-body decoherence involving multiple incident photons and multiple gate excitations forming the switch. Aside from offering insights into the operational capacity of realistic photon switching capabilities, our work provides a complete description of spin wave decoherence in a Rydberg quantum optics setting, and has immediate relevance to a number of further applications employing photon storage in Rydberg media.

  7. Non-operative management of arterial liver hemorrhages

    Energy Technology Data Exchange (ETDEWEB)

    Goerich, J.; Rilinger, N.; Vogel, J.; Sokiranski, R.; Brambs, H.J. [Dept. of Radiology, University of Ulm (Germany); Brado, M. [Dept. of Radiology, Univ. of Heidelberg (Germany); Huppert, P. [Dept. of Radiology, Univ. of Tuebingen (Germany); Siech, M.; Ganzauge, F.; Beger, H.G. [Dept. of Surgery, Univ. of Ulm (Germany)

    1999-02-01

    A retrospective evaluation of embolotherapy in patients with arterial liver hemorrhages was carried out. Twenty-six patients, ranging in age from 10 days to 77 years with active arterial liver hemorrhages, underwent non-surgical embolotherapy. Bleeding was attributed to trauma (n = 21), tumor (n = 3), pancreatitis (n = 1), or unknown cause (n = 1). Twenty-nine embolizations were performed via a transfemoral (n = 26) or biliary (n = 2) approach. One bare Wallstent was placed into the common hepatic artery via to an axillary route to cover a false aneurysm due to pancreatitis. Treatment was controlled in 4 patients by cholangioscopy (n = 2) or by intravascular ultrasound (n = 2). Prior surgery had failed in 3 patients. Intervention controlled the hemorrhage in 24 of 26 (92 %) patients within 24 h. Embolotherapy failed in 1 patient with pancreatic carcinoma and occlusion of the portal vein. In 1 patient with an aneurysm of the hepatic artery treated by Wallstent insertion, total occlusion was not achieved in the following days, as demonstrated by CT and angiography. However, colour Doppler flow examination showed no flow in the aneurysm 6 months later. Complications were one liver abscess, treated successfully by percutaneous drainage for 10 days, and one gallbladder necrosis after superselective embolization of the cystic artery. Embolization is a effective tool with a low complication rate in the treatment of liver artery hemorrhage, even in patients in whom surgery has failed. (orig.) (orig.) With 2 figs., 26 refs.

  8. On the repetitive operation of a self-switched transversely excited atmosphere CO2 laser

    Indian Academy of Sciences (India)

    Pallavi Raote; Gautam Patil; J Padma Nilaya; D J Biswas

    2010-11-01

    The repetition rate capability of self-switched transversely excited atmosphere (TEA) CO2 laser was studied for different gas flow configurations. For an optimized gas flow configuration, repetitive operation was achieved at a much smaller gas replenishment factor between two successive pulses when compared with repetitive systems energized by conventional pulsers.

  9. OPERATIONAL RESEARCHES OF TRACK GAUGE AND POSITIONS IN THE TERMS OF SWITCH LATERAL DIRECTION

    Directory of Open Access Journals (Sweden)

    V. V. Rybkin

    2010-06-01

    Full Text Available The results of operational research of lateral direction of switches of type P65 mark 1/11-1/9 on reinforced concrete bars on the track gauge and the direction in plan are presented in the article. The characteristic parts of the lateral direction in terms of the influence of geometrical position on the interaction with rolling stock are determined.

  10. 78 FR 26110 - Kicking Cars and Going Between Rolling Equipment During Flat Switching Operations

    Science.gov (United States)

    2013-05-03

    .... After the two tank cars were kicked into the yard track by the switchman, he noticed that the knuckle on... adoption of car-handling procedures during flat switching operations at certain locations and to re-emphasize the importance of following procedures when going between rolling equipment due to the...

  11. T-Bar Utilization for Concomitant Coronary Artery Bypass Graft Operation and Left Upper Lobectomy.

    Science.gov (United States)

    Mitropoulos, Fotios; Kanakis, Meletios A; Apostolou, Anastasios; Chatzis, Andrew; Contrafouris, Constantinos; Apostolidis, Christos; Lioulias, Achilleas

    2016-01-01

    Management in patients with coexisting coronary artery disease and lung carcinoma is usually a two-stage operation, with the cardiac surgery procedure followed by pulmonary resection at a later time. Delayed tumor resection on the other hand may be detrimental. Off-pump coronary artery bypass grafting could facilitate concomitant lung resection at one stage via median sternotomy. T-bar retractor may be a useful tool in the surgical approach of this combined operation.

  12. T-Bar Utilization for Concomitant Coronary Artery Bypass Graft Operation and Left Upper Lobectomy

    Directory of Open Access Journals (Sweden)

    Fotios Mitropoulos

    2016-01-01

    Full Text Available Management in patients with coexisting coronary artery disease and lung carcinoma is usually a two-stage operation, with the cardiac surgery procedure followed by pulmonary resection at a later time. Delayed tumor resection on the other hand may be detrimental. Off-pump coronary artery bypass grafting could facilitate concomitant lung resection at one stage via median sternotomy. T-bar retractor may be a useful tool in the surgical approach of this combined operation.

  13. Operative treatment for cervical fracture and dislocation with blunt unilateral vertebral artery injury

    Institute of Scientific and Technical Information of China (English)

    JIANG Tao; REN Xian-jun; WANG Wei-dong; ZHANG Xia; LI Chang-qing; HAO Yong

    2010-01-01

    Objective: To investigate risks and clinical effects of operative treatment for cervical vertebral fracture and dislocation associated with unilateral vertebral artery injury.Methods: This group consisted of 76 cases of closed cervical spine trauma combined with unilateral vertebral artery injury (23 cases of bilateral facet dislocation, 28 unilateral facet dislocation and 25 fracture). All patients underwent prospective examination of cervical spine MRI and vertebral artery two-dimensional time-of-flight (2D TOF)magnetic resonance angiography (MRA), and anterior cervical decompression. The healthy vertebral artery paths were evaluated before the surgery, and were protected during the surgery according to the anatomical signs.Results: There were no acute or chronic clinical damage symptoms in 76 cases after surgery. No neural damage symptoms were observed in patients with normal neural functions. The neural functions of incomplete paralyzed patients were improved in different grades.Conclusions: Reliable anterior operation can produce good results for cervical fracture and dislocation with unilateral vertebral artery injury. Detecting the course of uninjured vertebral artery before operation and locating the anatomical site during operation are effective to avoid damaging vertebral artery of uninjured side.

  14. Hardware enabled performance counters with support for operating system context switching

    Science.gov (United States)

    Salapura, Valentina; Wisniewski, Robert W.

    2015-06-30

    A device for supporting hardware enabled performance counters with support for context switching include a plurality of performance counters operable to collect information associated with one or more computer system related activities, a first register operable to store a memory address, a second register operable to store a mode indication, and a state machine operable to read the second register and cause the plurality of performance counters to copy the information to memory area indicated by the memory address based on the mode indication.

  15. Iliac artery pseudoaneurysm after lumbar disc hernia operation

    Directory of Open Access Journals (Sweden)

    Mehmet Atay

    2016-03-01

    Full Text Available Lumbar disc herniation surgery is usually performed through a posterior approach. Vascular injuries can be counted among the complications. 39 years old male patient had lower extremity pain which has started after lumbar disc herniation surgery and continued for a month. Iliac arterial pseudoaneurysm has been detected in computerized tomography. It was successfully treated with vascular surgery [Cukurova Med J 2016; 41(0.100: 5-7

  16. Switching circuits based on comparison operations and multiple-β transistor

    Institute of Scientific and Technical Information of China (English)

    吴训威; 杭国强

    1997-01-01

    By using comparison operations, three basic operations, AND, OR and NOT, in Boolean algebra are re-defined Based on the characteristic that the voltage signals are easy to implement comparison operation, various logic functions realized by connecting emitters of the bipolar transistor are analyzed. Furthermore, a novel multiple-β transistor and the linear AND-OR gate, which is composed of the transistor, are investigated. Super high-speed characteristic and multiple-cascade capability of the linear AND-OR gate are verified by PSPICE simulation. Based on the analysis of high-speed switch, which is compatible with the linear AND-OR gate, a high-speed inverter is proposed, which is composed of multiple-β transistors. The corresponding flip-flop design is also given. Finally, the criterion for using linear AND-OR gate to design high-speed switching circuits are presented. Some combinational and sequential circuits are designed as the practical examples. Discussion indicates that the switching circuits bas

  17. Large Area Silicon Carbide Vertical JFETs for 1200 V Cascode Switch Operation

    Directory of Open Access Journals (Sweden)

    Victor Veliadis

    2008-01-01

    Full Text Available SiC VJFETs are excellent candidates for reliable high-power/temperature switching as they only use pn junctions in the active device area where the high-electric fields occur. VJFETs do not suffer from forward voltage degradation, exhibit excellent short-circuit performance, and operate at 300°C. 0.19 cm2 1200 V normally-on and 0.15 cm2 low-voltage normally-off VJFETs were fabricated. The 1200-V VJFET outputs 53 A with a forward drain voltage drop of 2 V and a specific onstate resistance of 5.4 mΩ cm2. The low-voltage VJFET outputs 28 A with a forward drain voltage drop of 3.3 V and a specific onstate resistance of 15 mΩ cm2. The 1200-V SiC VJFET was connected in the cascode configuration with two Si MOSFETs and with a low-voltage SiC VJFET to form normally-off power switches. At a forward drain voltage drop of 2.2 V, the SiC/MOSFETs cascode switch outputs 33 A. The all-SiC cascode switch outputs 24 A at a voltage drop of 4.7 V.

  18. On the operation of switch-less transversely excited atmosphere CO2 lasers in the oscillator and amplifier configurations

    Indian Academy of Sciences (India)

    Gautam C Patil; Pallavi Raote; J Padma Nilaya; D J Biswas

    2010-11-01

    The work presented in this paper deals with the triggering aspect of a switch-less laser. Many methods were utilized to affect the operation of two switch-less lasers in the oscillator–amplifier configuration. Most satisfactory performance in terms of the range and reliability of the delay was obtained with the LC inversion-based triggering option.

  19. [Operations on carotid arteries in an acute stage of ischaemic stroke].

    Science.gov (United States)

    Ignat'ev, I M

    2011-01-01

    The present study was aimed at specifying the indications for operations performed on carotid arteries in an acute period of ischaemic stroke and assessing the results thus obtained. Between January 2008 and July 2010, we carried out a total of 372 operations on carotid arteries in three hundred and sixty patients. Of these, thirty-two subjects were operated on in an acute period of stroke. Neurovisualization was performed by means of magnetic resonance imaging (MRI) and computed tomography (CT). The condition of the carotid arteries was assessed by means of duplex scanning (DS). The operations performed on the carotid arteries were as follows: thrombembolectomy (n=4), carotid thrombendarterectomy (n 5), carotid endarterectomy (CEAE, n=21), and stent grafting of the internal carotid arteries (1СA, n 2). Five CEAE operations were carried out after thrombolysis. The interventions on the carotid arteries were performed within 6 hours to 12 days from the onset of the first symptoms of ischaemic stroke. Neurologists were actively engaged in both determining the indications for the operations and monitoring of neurological functions. There were no perioperative complications encountered. Regression of the neurological deficit during 7 days of in-hospital follow up occurred in sixteen patients (50%) (neurological deficit scoring 1-2 by the Rankin scale). One patient (3%) developed ischaemic stroke on postoperative day 3 after CEAE. Two patients were diagnosed as having transitory ischaemic attacks. Stenting turned out successful in the both patients. The remote results at terms ranging from 12 months to 2 years were followed up in fifteen patients. Of these, twelve patients (80%) showed complete restoration of neurological functions (Rankin scale scoring 0). Neither lethal outcomes nor relapsing strokes were observed over the follow-up period. The obtained outcomes strongly suggest certain advantages and advisability of active surgical policy of treating patients

  20. Contribution of Nrf2 to Atherogenic Phenotype Switching of Coronary Arterial Smooth Muscle Cells Lacking CD38 Gene

    Directory of Open Access Journals (Sweden)

    Ming Xu

    2015-08-01

    Full Text Available Background/Aims: Recent studies have indicated that CD38 gene deficiency results in dedifferentiation or transdifferentiation of arterial smooth muscle cells upon atherogenic stimulations. However, the molecular mechanisms mediating this vascular smooth muscle (SMC phenotypic switching remain unknown. Methods & Results: In the present study, we first characterized the phenotypic change in the primary cultures of coronary arterial myocytes (CAMs from CD38-/- mice. It was shown that CD38 deficiency decreased the expression of contractile marker calponin, SM22α and α-SMA but increased the expression of SMC dedifferentiation marker, vimentin, which was accompanied by enhanced cell proliferation. This phenotypic change in CD38-/- CAMs was enhanced by 7-ketocholesterol (7-Ket, an atherogenic stimulus. We further found that the CD38 deficiency decreased the expression and activity of nuclear factor E2-related factor 2 (Nrf2, a basic leucine zipper (bZIP transcription factor sensitive to redox regulation. Similar to CD38 deletion, Nrf2 gene silencing increased CAM dedifferentiation upon 7-Ket stimulation. In contrast, the overexpression of Nrf2 gene abolished 7-Ket-induced dedifferentiation in CD38-/- CAMs. Given the sensitivity of Nrf2 to oxidative stress, we determined the role of redox signaling in the regulation of Nrf2 expression and activity associated with CD38 effect in CAM phenotype changes. It was demonstrated that in CD38-/- CAMs, 7-Ket failed to stimulate the production of O2-., while in CD38+/+ CAMs 7-Ket induced marked O2-. production and enhancement of Nrf2 activity, which was substantially attenuated by NOX4 gene silencing. Finally, we demonstrated that 7-Ket-induced and NOX4-dependent O2-. production was inhibited by 8-Br-cADPR, an antagonist of cADPR or NED-19, an antagonist of NAADP as product of CD38 ADP-ribosylcyclase, which significantly inhibited the level of cytosolic Ca2+ and the activation of Nrf2 under 7-Ket. Conclusion

  1. Two-Dimensional Simulation of Mass Transfer in Unitized Regenerative Fuel Cells under Operation Mode Switching

    Directory of Open Access Journals (Sweden)

    Lulu Wang

    2016-01-01

    Full Text Available A two-dimensional, single-phase, isothermal, multicomponent, transient model is built to investigate the transport phenomena in unitized regenerative fuel cells (URFCs under the condition of switching from the fuel cell (FC mode to the water electrolysis (WE mode. The model is coupled with an electrochemical reaction. The proton exchange membrane (PEM is selected as the solid electrolyte of the URFC. The work is motivated by the need to elucidate the complex mass transfer and electrochemical process under operation mode switching in order to improve the performance of PEM URFC. A set of governing equations, including conservation of mass, momentum, species, and charge, are considered. These equations are solved by the finite element method. The simulation results indicate the distributions of hydrogen, oxygen, water mass fraction, and electrolyte potential response to the transient phenomena via saltation under operation mode switching. The hydrogen mass fraction gradients are smaller than the oxygen mass fraction gradients. The average mass fractions of the reactants (oxygen and hydrogen and product (water exhibit evident differences between each layer in the steady state of the FC mode. By contrast, the average mass fractions of the reactant (water and products (oxygen and hydrogen exhibit only slight differences between each layer in the steady state of the WE mode. Under either the FC mode or the WE mode, the duration of the transient state is only approximately 0.2 s.

  2. Preparo do ventrículo subpulmonar através de dois diferentes modelos ajustáveis de bandagem do tronco pulmonar: estudo experimental Preparation of the pulmonary ventricle for arterial switch operation using two adjustable devices for pulmonary trunk obstruction: an experimental study

    Directory of Open Access Journals (Sweden)

    Luiz Fernando CANÊO

    2001-03-01

    Full Text Available Dois modelos de dispositivos ajustáveis foram implantados em cabritos jovens, com o objetivo de avaliar suas capacidades de bandagem do tronco pulmonar (TP e eficiência no treinamento do ventrículo subpulmonar. Foram utilizados 3 grupos de 7 animais, submetidos ao implante de cateter balão (grupo I, implante de dispositivo de bandagem externa (grupo II e para obtenção dos pesos dos ventrículos direito (VD, esquerdo (VE e septo interventricular em condições normais (grupo controle. Os animais foram submetidos a ajustes progressivos dos dispositivos, a cada 24 horas, durante um período de 96 horas, avaliados através de monitorização hemodinâmica e ecocardiograma seriado. A hipertrofia ventricular foi avaliada através de parâmetros morfológicos e de microscopia óptica. Todos os animais concluíram o período de treinamento proposto. O gradiente VD-TP, a razão VD/VE e a pressão sistólica do VD foram significativamente maiores no grupo II (p0,05. O perímetro e a área dos miócitos mostraram um aumento significativo no final do treinamento, comparados à amostra retirada no momento do implante dos dispositivos. Observamos maior grau de estenose do TP com dispositivo de bandagem externa, porém ambos tiveram a capacidade e a eficiência de preparar o ventrículo subpulmonar.Two adjustable pulmonary artery banding devices were implanted in 14 young goats to evaluate their efficacy for the training of the pulmonary ventricle (right ventricle. An obstructing balloon catheter was placed in the lumen of the pulmonary artery in 7 animals (group I and other 7 animals (group II underwent implantation of an external pulmonary banding device. As a control group for septum, left and right ventricle weights a third group of 7 animals was used. Right ventricle (RV load was increased gradually, at 24 hours intervals, for 96 hours. RV muscle mass evolution was assessed by echocardiography and by optical microscopy. All animals completed the

  3. [Transposition of Great Artery].

    Science.gov (United States)

    Konuma, Takeshi; Shimpo, Hideto

    2015-07-01

    Transposition of the great artery is one of common congenital cardiac disease resulting cyanosis. Death occurs easily in untreated patients with transposition and intact ventricular septal defect (VSD) in infancy at a few days of age when posterior descending coronary artery (PDA) closed. Since there are 2 parallel circulations, flow from pulmonary to systemic circulation is necessary for systemic oxygenation, and Balloon atrial septostomy or prostaglandin infusion should be performed especially if patient do not have VSD. Although the advent of fetal echocardiography, it is difficult to diagnose the transposition of the great arteries (TGA) as abnormality of great vessels is relatively undistinguishable. The diagnosis of transposition is in itself an indication for surgery, and arterial switch procedure is performed in the case the left ventricle pressure remains more than 2/3 of systemic pressure. Preoperative diagnosis is important as associated anomalies and coronary artery branching patterns are important to decide the operative indication and timing of surgery.

  4. A bulldog clamp that was forgotten during a coronary artery bypass operation 8 years ago.

    Science.gov (United States)

    Celkan, Mehmet Adnan; Bayatli, Kivanc

    2012-10-01

    Prevention of retained foreign bodies in the pericardial cavity is critical for patient safety. We report a patient with a bulldog clamp that was forgotten during a coronary artery bypass operation 8 years ago, which was detected by chance and removed.

  5. Characteristics of switched reluctance motor operating in continuous and discontinuous conduction mode

    Directory of Open Access Journals (Sweden)

    Ćalasan Martin P.

    2013-01-01

    Full Text Available This paper presents mechanical characteristics of Switched Reluctance Motor (SRM when it operates in Discontinuous Conduction Mode (DCM or in Continuous Conduction Mode (CCM, i.e. when the current through the phase coils (windings flows discontinuously or continuously. Firstly, in order to maximize the output power of SRM optimization of its control parameters was performed, such that the peak and RMS values of the current do not exceed the predefined values. The optimal control parameters vs. rotation speed, as well as the corresponding characteristics of torque, power and efficiency. It is shown that with CCM the machine torque (power, at high speed, can be increased.

  6. A quantum switching architecture on the basis of limited nonlocal operation

    Institute of Scientific and Technical Information of China (English)

    JIANG Min; ZHANG Zeng-ke; DONG Dao-yi

    2006-01-01

    Quantum information system is fragile to be disturbed by the external environment. Quantum switching architecture is one of the promising schemes for transferring input quantum data to its destination port substituted for fully connected quantum networks. Since at present, interactions between the qubits are limited to a small number of neighboring qubits, one novel approach was extended, and the improved architecture was further demonstrated under limited nonlocal operation. The performance evaluation shows that the whole architecture with improved control module can achieve a time complexity of O(n2) and will be more feasible for physical realization.

  7. Operative strategy of complex internal carotid artery-posterior communicating artery aneurysms Defensive effect on perioperative nerve injury

    Institute of Scientific and Technical Information of China (English)

    Xinmin Wang; Wende Xiong; Xuqin Li

    2007-01-01

    BACKGROUND: The two problems in treating intracranial aneurysm are the vascular reconstruction and brain protection, especially for complex internal carotid artery-posterior communicating artery (ICA-PComA)aneurysms.OBJECTIVE: To analyze the anatomic features and operative technique of complex ICA-PComA aneurysms, and investigate how to better protect the brain tissue.DESIGN: A retrospective case analysis.SETTING: Department ofNeurosurgery, Dalian Central Hospital.PARTICIPANTS: Totally 154 inpatients with ICA-PComA aneurysms were selected from the Department of Neurosurgery, Dalian Central Hospital from January 1998 to December 2006, including 19 cases (12.3%)of complex ICA-PComA aneurysms, 8 males and 11 females, 38 - 67 years of age. Informed contents for surgery and observation were obtained from all the patients or their relatives.METHODS: The clinical manifestations, including initial symptoms and Hunt&Hess grading, were observed. Corresponding strategies were selected for different types of ICA-PComA aneurysms. The patients were followed up at 3 months postoperatively. According to the results of Glasgow scoring, the curative effects were classified as good (4 - 5 points), bad (2 - 3 points) and dead (1 point). The results at discharge were taken as early results, whereas the follow-up results as late results.MAIN OUTCOME MEASURES: Clinical manifestations and curative effects of the patients.RESULTS: All the 19 patients with ICA-PComA were involved in the analysis of results. For clinical manifestations, the initial symptoms were subarachnoid hemorrhage (n =15), paralysis of oculomotor nerve (n =3), and occasional attack (n =1); The Hunt&Hess grading was grade Ⅰ in 4 cases, grade Ⅱ in 6 cases,grade Ⅲ in 6 cases, grade Ⅳ in 2 cases, and grade Ⅴ in 1 case. The curative effects were that aneurysm breakage and bleeding occurred in 6 cases perioperatively, uncomplete clipping of aneurysm in 2 cases and constriction of parent artery in 1 case. The

  8. Towards Analyzing Crossover Operators in Evolutionary Search via General Markov Chain Switching Theorem

    CERN Document Server

    Yu, Yang; Zhou, Zhi-Hua

    2011-01-01

    Evolutionary algorithms (EAs), simulating the evolution process of natural species, are used to solve optimization problems. Crossover (also called recombination), originated from simulating the chromosome exchange phenomena in zoogamy reproduction, is widely employed in EAs to generate offspring solutions, of which the effectiveness has been examined empirically in applications. However, due to the irregularity of crossover operators and the complicated interactions to mutation, crossover operators are hard to analyze and thus have few theoretical results. Therefore, analyzing crossover not only helps in understanding EAs, but also helps in developing novel techniques for analyzing sophisticated metaheuristic algorithms. In this paper, we derive the General Markov Chain Switching Theorem (GMCST) to facilitate theoretical studies of crossover-enabled EAs. The theorem allows us to analyze the running time of a sophisticated EA from an easy-to-analyze EA. Using this tool, we analyze EAs with several crossover o...

  9. 40-GHz operation of a single-flux-quantum (SFQ) 4 × 4 switch scheduler

    Science.gov (United States)

    Kameda, Y.; Yorozu, S.; Hashimoto, Y.; Terai, H.; Fujimaki, A.; Yoshikawa, N.

    2006-10-01

    We designed a single-flux-quantum (SFQ) scheduler for a 4 × 4 network switch. It receives requests serially and arbitrates them. Fair scheduling is achieved by using a round-robin priority pointer at each output port. The pointer is updated so that the input port that was granted permission has the lowest priority in the next scheduling cycle. We divided the scheduler into sub-blocks, which were separately designed. The sub-blocks, which have asynchronous interfaces, were then connected with passive transmission lines. Ladder-type on-chip clock generators were included in the circuit for high-speed operation. Using logic simulation, we verified the scheduler test circuit. The scheduler test circuit was composed of about 3000 Josephson junctions. We tested the scheduler circuit at high speed and confirmed correct operations at over 40 GHz.

  10. Review on SOA-MZl-based photonic add/drop and switching operations

    Institute of Scientific and Technical Information of China (English)

    Claudio PORZI; Giovanni SERAFINO; Sergio PINNA; An NGUYEN; Giampiero CONTESTABILE; Antonclla BOGONI

    2013-01-01

    Semiconductor optical amplifier-Mach-Zehnder interferometer (SOA-MZI) is a technologically mature optical device that can be exploited for a wide range of operations on both amplitude and phase modulated signals, with performance limited by the carrier lifetime in the SOAs. Recent advances on SOA structures have demonstrated their suitability for high quality, ultra-fast photonic signal processing, making SOA-MZI a good candidate for elaborating signals in new generation high-capacity optical networks. Dynamic wavelength switching/routing and add/drop operations are expected to bring benefits in future optical networks in terms of improved system flexibility and efficiency. The capability of performing such operations directly in the optical domain can significantly reduce the number of opto/electrical and electro/optical conversions in the routing nodes, reducing their power consumption and their latency time. Moreover, since phase-shift keying (PSK) formats or other advanced modulation formats involving both amplitude and phase modulation, start to coexist in optical communication systems with the conventional on-off keying (OOK) modulation format, the availability of a single device, suitable for processing all these different signals, is mandatory. The SOA-MZI fits all these requirements for both OOK and constant-envelope phase-modulated signals, providing a compact and flexible solution. Here we review on the use of the SOA-MZI for carrying out all- optical switching operations, by realizing wavelength conversion and add/drop functionalities, both for OOK and differential binary phase shift keying (DPSK) signals up to 40Gb/s. Power penalties lower than 2 dB are demonstrated in all cases.

  11. Operation of an ADR using helium exchange gas as a substitute for a failed heat switch

    Science.gov (United States)

    Shirron, P.; DiPirro, M.; Kimball, M.; Sneiderman, G.; Porter, F. S.; Kilbourne, C.; Kelley, R.; Fujimoto, R.; Yoshida, S.; Takei, Y.; Mitsuda, K.

    2014-11-01

    The Soft X-ray Spectrometer (SXS) is one of four instruments on the Japanese Astro-H mission, which is currently planned for launch in late 2015. The SXS will perform imaging spectroscopy in the soft X-ray band (0.3-12 keV) using a 6 × 6 pixel array of microcalorimeters cooled to 50 mK. The detectors are cooled by a 3-stage adiabatic demagnetization refrigerator (ADR) that rejects heat to either a superfluid helium tank (at 1.2 K) or to a 4.5 K Joule-Thomson (JT) cryocooler. Four gas-gap heat switches are used in the assembly to manage heat flow between the ADR stages and the heat sinks. The engineering model (EM) ADR was assembled and performance tested at NASA/GSFC in November 2011, and subsequently installed in the EM dewar at Sumitomo Heavy Industries, Japan. During the first cooldown in July 2012, a failure of the heat switch that linked the two colder stages of the ADR to the helium tank was observed. Operation of the ADR requires some mechanism for thermally linking the salt pills to the heat sink, and then thermally isolating them. With the failed heat switch unable to perform this function, an alternate plan was devised which used carefully controlled amounts of exchange gas in the dewar's guard vacuum to facilitate heat exchange. The process was successfully demonstrated in November 2012, allowing the ADR to cool the detectors to 50 mK for hold times in excess of 10 h. This paper describes the exchange-gas-assisted recycling process, and the strategies used to avoid helium contamination of the detectors at low temperature.

  12. Operation of an ADR Using Helium Exchange Gas as a Substitute for a Failed Heat Switch

    Science.gov (United States)

    Shirron, P.; DiPirro, M.; Kimball, M.; Sneiderman, G.; Porter, F. S.; Kilbourne, C.; Kelley, R.; Fujimoto, R.; Yoshida, S.; Takei, Y.; Mitsuda, K.

    2014-01-01

    The Soft X-ray Spectrometer (SXS) is one of four instruments on the Japanese Astro-H mission, which is currently planned for launch in late 2015. The SXS will perform imaging spectroscopy in the soft X-ray band (0.3-12 keV) using a 6 6 pixel array of microcalorimeters cooled to 50 mK. The detectors are cooled by a 3-stage adiabatic demagnetization refrigerator (ADR) that rejects heat to either a superfluid helium tank (at 1.2 K) or to a 4.5 K Joule-Thomson (JT) cryocooler. Four gas-gap heat switches are used in the assembly to manage heat flow between the ADR stages and the heat sinks. The engineering model (EM) ADR was assembled and performance tested at NASA/GSFC in November 2011, and subsequently installed in the EM dewar at Sumitomo Heavy Industries, Japan. During the first cooldown in July 2012, a failure of the heat switch that linked the two colder stages of the ADR to the helium tank was observed. Operation of the ADR requires some mechanism for thermally linking the salt pills to the heat sink, and then thermally isolating them. With the failed heat switch unable to perform this function, an alternate plan was devised which used carefully controlled amounts of exchange gas in the dewar's guard vacuum to facilitate heat exchange. The process was successfully demonstrated in November 2012, allowing the ADR to cool the detectors to 50 mK for hold times in excess of 10 h. This paper describes the exchange-gas-assisted recycling process, and the strategies used to avoid helium contamination of the detectors at low temperature.

  13. A versatile retractor for use in harvesting the internal mammary artery and performing standard cardiac operations.

    Science.gov (United States)

    Phillips, S J; Core, M

    1989-04-01

    A versatile retractor is described that can be used to harvest either mammary artery without disturbing the operative field and can be converted to a standard sternotomy retractor. It uses the principle of elevating the cut sternal edge and applying external pressure to the area of the costochrondal junction to rotate the mammary pedicle into view. We have used this retractor and found it to be very efficient in exposing the mammary pedicle while being atraumatic to the sternum.

  14. Stenosis of the branches of the neopulmonary artery after the arterial switch operation: A cardiac magnetic resonance imaging study

    Directory of Open Access Journals (Sweden)

    Boban Thomas

    2013-01-01

    Conclusions: Cardiac MR can be used as a comprehensive non-invasive imaging technique to diagnose stenosis of the branches of the neopulmonary after the ASO, allowing evaluation of anatomy and function of the neoPA, its branches, and the differential perfusion to each lung, thus facilitating clinical decision making.

  15. Stability of Switched Feedback Time-Varying Dynamic Systems Based on the Properties of the Gap Metric for Operators

    Directory of Open Access Journals (Sweden)

    M. De la Sen

    2012-01-01

    Full Text Available The stabilization of dynamic switched control systems is focused on and based on an operator-based formulation. It is assumed that the controlled object and the controller are described by sequences of closed operator pairs (L,C on a Hilbert space H of the input and output spaces and it is related to the existence of the inverse of the resulting input-output operator being admissible and bounded. The technical mechanism addressed to get the results is the appropriate use of the fact that closed operators being sufficiently close to bounded operators, in terms of the gap metric, are also bounded. That philosophy is followed for the operators describing the input-output relations in switched feedback control systems so as to guarantee the closed-loop stabilization.

  16. 17. Global and regional left ventricular function after arterial switch operation: A speckle tracking echocardiography study

    Directory of Open Access Journals (Sweden)

    Giovanni Di Salvo

    2015-10-01

    Conclusions: To the best of our knowledge this is the largest study on ASO patients by using STE. We demonstrated that in asymptomatic ASO patients despite a normal LV EF (⩾55% there is a significant reduction in longitudinal myocardial deformation while circumferential deformation and LV torsion are preserved, in order to maintain a normal LV EF.

  17. Nanoelectromechanical switch operating by tunneling of an entire C-60 molecule

    DEFF Research Database (Denmark)

    Danilov, Andrey V.; Hedegård, Per; Golubev, Dimitrii S.;

    2008-01-01

    We present a solid state single molecule electronic device where switching between two states with different conductance happens predominantly by tunneling of an entire C-60 molecule. This conclusion is based on a novel statistical analysis of similar to 10(5) switching events. The analysis yields...... (i) the relative contribution of tunneling, current induced heating and thermal fluctuations to the switching mechanism, (ii) the voltage dependent energy barrier (similar to 100-200 meV) separating the two states of the switch and (iii) the switching attempt frequency, omega(0) corresponding to a 2...

  18. Voltage- and current-activated metal–insulator transition in VO2-based electrical switches: a lifetime operation analysis

    Directory of Open Access Journals (Sweden)

    Aurelian Crunteanu, Julien Givernaud, Jonathan Leroy, David Mardivirin, Corinne Champeaux, Jean-Christophe Orlianges, Alain Catherinot and Pierre Blondy

    2010-01-01

    Full Text Available Vanadium dioxide is an intensively studied material that undergoes a temperature-induced metal–insulator phase transition accompanied by a large change in electrical resistivity. Electrical switches based on this material show promising properties in terms of speed and broadband operation. The exploration of the failure behavior and reliability of such devices is very important in view of their integration in practical electronic circuits. We performed systematic lifetime investigations of two-terminal switches based on the electrical activation of the metal–insulator transition in VO2 thin films. The devices were integrated in coplanar microwave waveguides (CPWs in series configuration. We detected the evolution of a 10 GHz microwave signal transmitted through the CPW, modulated by the activation of the VO2 switches in both voltage- and current-controlled modes. We demonstrated enhanced lifetime operation of current-controlled VO2-based switching (more than 260 million cycles without failure compared with the voltage-activated mode (breakdown at around 16 million activation cycles. The evolution of the electrical self-oscillations of a VO2-based switch induced in the current-operated mode is a subtle indicator of the material properties modification and can be used to monitor its behavior under various external stresses in sensor applications.

  19. A Coupled Field Multiphysics Modeling Approach to Investigate RF MEMS Switch Failure Modes under Various Operational Conditions

    Directory of Open Access Journals (Sweden)

    Khaled Sadek

    2009-10-01

    Full Text Available In this paper, the reliability of capacitive shunt RF MEMS switches have been investigated using three dimensional (3D coupled multiphysics finite element (FE analysis. The coupled field analysis involved three consecutive multiphysics interactions. The first interaction is characterized as a two-way sequential electromagnetic (EM-thermal field coupling. The second interaction represented a one-way sequential thermal-structural field coupling. The third interaction portrayed a two-way sequential structural-electrostatic field coupling. An automated substructuring algorithm was utilized to reduce the computational cost of the complicated coupled multiphysics FE analysis. The results of the substructured FE model with coupled field analysis is shown to be in good agreement with the outcome of previously published experimental and numerical studies. The current numerical results indicate that the pull-in voltage and the buckling temperature of the RF switch are functions of the microfabrication residual stress state, the switch operational frequency and the surrounding packaging temperature. Furthermore, the current results point out that by introducing proper mechanical approaches such as corrugated switches and through-holes in the switch membrane, it is possible to achieve reliable pull-in voltages, at various operating temperatures. The performed analysis also shows that by controlling the mean and gradient residual stresses, generated during microfabrication, in conjunction with the proposed mechanical approaches, the power handling capability of RF MEMS switches can be increased, at a wide range of operational frequencies. These design features of RF MEMS switches are of particular importance in applications where a high RF power (frequencies above 10 GHz and large temperature variations are expected, such as in satellites and airplane condition monitoring.

  20. Mode-locked and Q-switched operation of a diode laser pumped Nd:YAG laser operating at 1.064 µm

    Science.gov (United States)

    Maker, G. T.; Keen, S. J.; Ferguson, A. I.

    1988-10-01

    We describe the performance of a mode-locked and Q-switched Nd:YAG laser operating at 1.064 μm, optically pumped by a 500 mW diode laser. The cw mode-locked system provides bandwidth-limited pulses of 55 ps duration, with a corresponding peak power of 3.3 W. When Q-switched the energy within the 100 ns pulse envelope is 10 μJ giving a peak power in the largest pulse of 7 kW. Preliminary results for operation at 1.32 μm are also reported.

  1. The clinical diagnosis of cranial nerve injuries at operations on the carotid arteries.

    Science.gov (United States)

    Fokin, Al An; Kuklin, A V; Belskaia, G N; Kuznetsova, M Iu; Alekhin, D I; Zotov, S P; Vardugin, I V; Sundukova, Ye I

    2003-01-01

    Operation on the carotid arteries (CA) prevent strokes in patients with occlusions and stenoses of these arteries. We have worked out the measures for preventing perioperative strokes. During interventions on the CA, iatrogenic injuries to the cranial nerves (CN) are paid little attention. 1186 patients underwent 1362 operations. There were 26 lethal outcomes and 38 strokes. 146 (0.7%) cases of CN injuries were documented. Of these, there were 2 (0.1%) injuries to the accessory nerve, 14 (1%) to the glossopharyngeal nerve, 28 (2%) to the hypoglossal nerve, 46 (3.4%) injuries to vagal nerve branches, and 56 (4.2%) to facial nerve branches. In 42 patients, neuropathies acquired the 'permanent' character. We describe the symptomatology of injuries to different CN pairs consequent on carotid operations and the algorithm of their diagnosis. CN injuries deteriorate the results of operations and decrease quality of life of the patients. Early diagnosis and correction of the sequelae of iatrogenic injuries to the CN is a reserve for the refinement of the results of operations on the CA.

  2. Transient Occlusion of Bilateral Internal Iliac Arteries Facilitates Bloodless Operative Field in Subcapsular Prostatectomy

    Directory of Open Access Journals (Sweden)

    Takumi Takeuchi

    2012-01-01

    Full Text Available Transurethral resection of the prostate is the gold standard of surgical treatment for benign prostatic hyperplasia (BPH. Nevertheless, open subcapsular prostatectomy is still performed for large BPH. While enucleation of prostatic adenoma is being performed, unneglectable bleeding can occur and surgeons need to rush to remove adenomas, often using fingers and in a blinded fashion. The blood supply to the prostatic capsule and adenoma can be reduced to a marked extent in subcapsular prostatectomy if the bilateral internal iliac arteries are transiently occluded. Thus, a bloodless operative field is reasonably acquired during enucleation of adenoma, which would, otherwise, be a cause for concern to surgeons due to bleeding. It is not always applicable, but it could be an option if the estimated volume of BPH is more than 100 mL. In two cases, bilateral internal iliac arteries were occluded with Bulldog clamps, and then adenomas of 159 and 97 g were enucleated.

  3. Validation of a Switching Operation in the External Grid of Gunfleet Sand Offshore Wind Farm by Means of EMT Simulations

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Okholm, J.; Holbøll, Joachim

    2011-01-01

    This paper presents the voltage signals occurring during a switching operation recorded in the external grid of Gunfleet Sands Offshore Wind Farm recorded with an Elspec measurement system. The measurements are compared to electromagnetic (EMT) simulations for validation of the wind farm model...

  4. 49 CFR 1242.67 - Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power...

    Science.gov (United States)

    2010-10-01

    ... terminal clerical; locomotive fuel; electric power purchased/produced for motive power; operating switches signals, retarders, and humps; and servicing locomotives (accounts XX-52-64, XX-52-65, XX-52-66, XX-52-59...; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive...

  5. High power CW and Q-switched operation of a diode-side-pumped Nd: YAG 1319-nm laser

    Institute of Scientific and Technical Information of China (English)

    Yunfang Wan; Kezhen Han; Yun Wang; Jingliang He

    2008-01-01

    We demonstrated the highly efficient continuous wave(CW)and Q-switched infrared laser from a diodeside-pumped Nd:YAG crystal.A CW output as high as 66 W at 1319 nm was achieved under the pump power of 460 W,corresponding to a coversion efficiency of 14.3%.A maximum average power of 8.9 W of TEM00 mode was obtained in Q-switched operation at the repetition rate of 8 kHz.The performance of the laser considering the thermal lens effect induced by pump power Was also analyzed.

  6. Simultaneous modelling of operative mortality and long-term survival after coronary artery bypass surgery.

    Science.gov (United States)

    Ghahramani, M; Dean, C B; Spinelli, J J

    2001-07-15

    Typical analyses of lifetime data treat the time to death or failure as the response variable and use a variety of modelling strategies such as proportional hazards or fully parametric, to investigate the relationship between the response and covariates. In certain circumstances it may be more natural to view the distribution of the response variable as consisting of two or more parts since the survival curve appears segmented. This article addresses such a scenario and we propose a model for simultaneously investigating the effects of covariates over the two segments. The model is an analogue of that proposed by Lambert for zero-inflated Poisson regression. The application is central to the model development and is concerned with survival after coronary artery bypass surgery. Here operative mortality, defined as death within 30 days after surgery, and long-term mortality, are viewed as distinct outcomes. For the application considered, the survivor function displays much steeper descent during the first 30 days after surgery, that is, for operative mortality, than after this period. An investigation of the effects of covariates on operative and long-term mortality after coronary artery bypass surgery illustrates the usefulness of the proposed model.

  7. Role of Nanoelectromechanical Switching in the Operation of Nanostructured Bi2Se3 Interlayers between Conductive Electrodes.

    Science.gov (United States)

    Kosmaca, Jelena; Andzane, Jana; Baitimirova, Margarita; Lombardi, Floriana; Erts, Donats

    2016-05-18

    We demonstrate a simple low-cost method of preparation of layered devices for opto- and thermoelectric applications. The devices consist of a functional Bi2Se3 layer of randomly oriented nanoplates and flexible nanobelts enclosed between two flat indium tin oxide (ITO) electrodes. The number of functional interconnections between the ITO electrodes and correspondingly the efficiency of the device can be increased by gradual nanoelectromechanical (NEM) switching of flexible individual Bi2Se3 nanobelts in the circuit. NEM switching is achieved through applying an external voltage to the device. For the first time, we investigate in situ NEM switching and breakdown parameters of Bi2Se3 nanobelts, visualize the processes occurring in the device under the influence of applied external voltage, and establish the limitations to the possible operational conditions.

  8. Fault Tolerant Operation of ISOP Multicell Dc-Dc Converter Using Active Gate Controlled SiC Protection Switch

    Directory of Open Access Journals (Sweden)

    Yusuke Hayashi

    2016-01-01

    Full Text Available An active gate controlled semiconductor protection switch using SiC-MOSFET is proposed to achieve the fault tolerant operation of ISOP (Input Series and Output Parallel connected multicell dc-dc converter. The SiC-MOSFET with high temperature capability simplifies the configuration of the protection circuit, and its on-resistance control by the active gate controller realizes the smooth protection without the voltage and the current surges. The first laboratory prototype of the protection switch is fabricated by using a SiC-MOSFET with a high frequency buck chopper for the active gate controller. The effectiveness of the proposed protection switch is verified, taking the impact of the volume reduction into account.

  9. Model-based statistical estimation of Sandia RF ohmic switch dynamic operation form stroboscopic, x-ray imaging.

    Energy Technology Data Exchange (ETDEWEB)

    Diegert, Carl F.

    2006-12-01

    We define a new diagnostic method where computationally-intensive numerical solutions are used as an integral part of making difficult, non-contact, nanometer-scale measurements. The limited scope of this report comprises most of a due diligence investigation into implementing the new diagnostic for measuring dynamic operation of Sandia's RF Ohmic Switch. Our results are all positive, providing insight into how this switch deforms during normal operation. Future work should contribute important measurements on a variety of operating MEMS devices, with insights that are complimentary to those from measurements made using interferometry and laser Doppler methods. More generally, the work opens up a broad front of possibility where exploiting massive high-performance computers enable new measurements.

  10. Resection of hilar cholangiocarcinoma with left hepatectomy after pre-operative embolization of the proper hepatic artery

    DEFF Research Database (Denmark)

    Yasuda, Yoshikazu; Larsen, Peter N; Ishibashi, Toshimitsu

    2010-01-01

    Right or right-extended hepatectomy including the caudate lobe is the most common treatment for hilar cholangiocarcinoma (HC). A 5-year survival of up to 60% can be achieved using this procedure if R0-resection is obtained. However, for some patients a left-sided liver resection is necessary to o......-operative embolization of the proper hepatic artery in an effort to induce development of arterial collaterals thus allowing the resection of the proper and right hepatic artery without vascular reconstruction....

  11. [Arterial reconstructive surgery of a coarctation of the abdominal aorta with involvement of renal and visceral arteries. Clinical and imagiologic evaluation 26 years after the operation].

    Science.gov (United States)

    Dinis da Gama, A

    2009-01-01

    The clinical case of a 13 years old female is reported, with the diagnosis of congenital coarctation of the abdominal aorta, with involvement of renal and visceral arteries, causing arterial hypertension and a systolic bruit in the auscultation of the epigastric and umbilical areas. Conventional angiography disclosed a stenotic process of the upper abdominal aorta, with concomitant ostial stenosis of the renal and digestive arteries, and post-stenotic dilatation of the celiac axis and superior mesenteric artery. The physical development of the patient, close to the adult pattern, allowed the performance of a complex revascularization procedure,accomplished in May 1984, consisting in the implantation of an aorto-aortic bypass graft, through the diaphragm, followed by visceral and renal revascularization, by means of independent prosthesis taken from the aortic bypass. The post-operative course was uneventful and blood pressure returned immediately to normal levels. Reviewed recently, the patient was found in good clinical condition,asymptomatic and with normal blood pressure, developing a normal family, social and Professional life. An Angio-CT evaluation, performed in February 2010, almost 26 years after the operation, revealed the complex revascularization procedure patent and working in excellent condition. To our knowledge, this seems to be the longest follow up of such a procedure employed successfully in a very rare clinical entity, thus justifying its presentation and divulgation.

  12. Sharing Water-related Information to Tackle Changes in the Hydrosphere - for Operational Needs (SWITCH-ON)

    Science.gov (United States)

    Arheimer, Berit

    2015-04-01

    Recently, a collaborative EU project started called SWITCH-ON (EU FP7 project No 603587) coordinated by SMHI to support the INSPIRE directive and the Open Data Strategy. The overall goal of the project is to establish a "one-stop-shop" web portal for easy access to European water information. The project will use open data, provide infrastructure for sharing and collaboration, and add value to society and research by repurposing and refining data from various sources. The SWITCH-ON project http://www.water-switch-on.eu/ will establish new forms of water research and facilitate the development of new products and services based on principles of sharing and community building in the water society. The SWITCH-ON objectives are to use open data for implementing: 1) an innovative spatial information platform (SIP) to find, bind, transform and publish data, 2) entirely new forms of collaborative research organised in a Virtual Water-Science Laboratory, open for any research group, 3) fourteen new operational products for water management and awareness, 4) outreach facilities for new water business and knowledge in line with the Europe's smart growth and environmental objectives. This poster will describe the overall project goals and especially the recent progress on developing a Virtual Water-Science Laboratory. Contact: waterswitchon@gmail.com

  13. Exploration of Syndrome Differentiation Patterns in Coronary Heart Disease Patients during Peri-Operative Stage of Coronary Artery Bypass Graft

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective: To explore the patterns of Syndrome Differentiation (SD) of coronary heart disease (CHD) patients in peri-operative stage of coronary artery bypass graft (CABG). Methods: One week after operation, thirty-seven CHD patients, who received CABG of internal mammary artery or great saphena vein under conventional general anesthesia with low or middle temperature extracorporeal circulation were differentiated as various syndromes, with the pre- or post-operational EKG, color Doppler echocardiography were done during and after operation. The hemodynamic parameters were monitored. Results: In the CHD patients, 64.9% were differentiated as Qi-Yin deficiency, 67.6% were complicated with phlegm syndrome and 62.2% with blood stasis, suggesting that Qi-deficiency, phlegm and stasis are the basic pathogenetic factors in patients with CABG. Moreover, the peri-operative syndrome was correlated with the condition of coronary artery lesion, heart and lung functions before operation, and the extracorporeal circulation time during the operation. Conclusion: TCM SD conducting in peri-operative stage might be useful in exploring the patterns of syndrome alteration which provided a basis for preventing peri-operative complications and elevating success rate of operation.

  14. Analysis on Operation Process and Common Faults of Bypass Switch%旁路代路操作及常见故障分析

    Institute of Scientific and Technical Information of China (English)

    李继光; 蒋国顺

    2015-01-01

    建立了220kV变电站典型模型,介绍了旁路代线路开关和旁路代主变变高开关的操作过程、注意事项及常见故障。指出旁路代路的主要过程为保护定值的整定及对旁路母线充电、代开关操作等,而代主变开关时,二次操作与一次操作配合必须紧密,否则将引起事故。%The 220kV typical substation model was established. Introduction was made to the operation process, matters needing attention and common fault when the bypass switch replaced the switching of line or the main transformer high switch. The main process of bypass switch replaced line is to protect the setting value, the bypass bus charging, switch replaced operation. When the bypass switch replaced the switching of the main transformer switch, the secondary electrical operation must match up the primary electrical operation closely, otherwise faults will take place.

  15. Robust Stability and H∞ Stabilization of Switched Systems with Time-Varying Delays Using Delta Operator Approach

    Directory of Open Access Journals (Sweden)

    Chen Qin

    2013-01-01

    Full Text Available This paper considers the problems of the robust stability and robust H∞ controller design for time-varying delay switched systems using delta operator approach. Based on the average dwell time approach and delta operator theory, a sufficient condition of the robust exponential stability is presented by choosing an appropriate Lyapunov-Krasovskii functional candidate. Then, a state feedback controller is designed such that the resulting closed-loop system is exponentially stable with a guaranteed H∞ performance. The obtained results are formulated in the form of linear matrix inequalities (LMIs. Finally, a numerical example is provided to explicitly illustrate the feasibility and effectiveness of the proposed method.

  16. Investigation of switching mechanism in HfOx-ReRAM under low power and conventional operation modes

    Science.gov (United States)

    Feng, Wei; Shima, Hisashi; Ohmori, Kenji; Akinaga, Hiroyuki

    2016-12-01

    Low-power resistive random access memory (LP-ReRAM) devices have attracted increasing attention owing to their advantages of low operation power. In this study, a vertical-type LP-ReRAM consisting of TiN/Ti/HfO2/TiN structure was fabricated. The switching mechanism for LP-ReRAM was elucidated as the conductive filament mechanism for conventional mode, and an interface-type switching mechanism for low power mode was proposed. The analysis of low frequency noise shows that power spectral density (PSD) is approximately proportional to 1/f for conventional operation mode. Nevertheless, for low power mode, the PSD of low resistance state (LRS) is proportional to 1/f, while that of high resistance state (HRS) is clear proportional to 1/f2. The envelope of multiple Lorentzian spectra of 1/f2 characteristics due to different traps reveals the characteristics of 1/f. For HRS of low power mode, a limited number of traps results in a characteristic of 1/f2. During the set process, the number of oxygen vacancies increases for LRS. Therefore, the PSD value is proportional to 1/f. Owing to the increase in the number of traps when the operation mode changes to conventional mode, the PSD value is proportional to 1/f. To the best of our knowledge, this is the first study that reveals the different noise characteristics in the low power operation mode from that in the conventional operation mode.

  17. Compact flat-panel gas-gap heat switch operating at 295 K

    NARCIS (Netherlands)

    Krielaart, M.A.R.; Vermeer, C.H.; Vanapalli, S.

    2015-01-01

    Heat switches are devices that can change from a thermally conducting (on-) state to an insulating (off-) state whenever the need arises. They enable adaptive thermal management strategies in which cooling rates are altered either spatially or temporally, leading to a substantial reduction in the en

  18. Thermal, spectral properties and Q-switched laser operation of Nd:SrLaAlO4 crystal

    Science.gov (United States)

    Liu, Shande; Dong, Lulu; Zhang, Xiao; Yao, Yongping; Xu, Yan; Ren, Tingqi; Zheng, Lihe; Su, Liangbi; Berkowski, Marek

    2017-02-01

    The thermal and spectral properties of a Nd:SrLaAlO4 (Nd:SLA) crystal were systematically studied, including thermal diffusivity, thermal expansion, specific heat, thermal conductivity, polarized absorption and emission spectra. Both continuous-wave (CW) and passively Q-switched Nd:SLA laser operations were investigated. The maximum CW output power of 3.54 W was obtained at 1.077 μm, corresponding to an optical-to-optical efficiency of 46.4%. In the passively Q-switched regime, the maximum average power, pulse repetition rate, and shortest pulse width were 1.8 W, 113 kHz, and 12.6 ns, respectively. All the results indicate that the Nd:SLA crystal is a highly efficient gain medium for laser applications.

  19. Utility of intra-operative capnogram to detect branch pulmonary artery obstruction following total correction of tetralogy of fallot

    Directory of Open Access Journals (Sweden)

    Garg Rajnish

    2011-01-01

    Full Text Available Branch pulmonary artery obstruction is one of the prime reasons for re-operation in patients who have undergone repair for tetralogy of Fallot. Branch pulmonary artery obstruction may develop over a period of time due to dilation of right ventricular outflow tract or it may be caused by residual stenosis after inadequate repair. This may lead to differential lung perfusion causing morbidity. Intra-operative capnogram monitoring reveals ventilation−perfusion relationship. We report two cases where the capnogram helped the diagnosis and management of branch pulmonary artery obstruction. We found a redundant patch in the first and an extra length of the homograft in second case which led to the obstruction. However, but for the changes in the intraoperative capnogram, this condition may by far remain undiagnosed considering the fact that it does not produce hemodynamic changes but can lead to postoperative morbidity.

  20. Myocardial imaging in patients with transposition of the great arteries. Comparison between Mustard and Rastelli operations

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Yasuo; Tanimoto, Takeshi (National Cardiovascular Center, Suita, Osaka (Japan)); Kohata, Tohru

    1982-12-01

    Thallium-201 myocardial imaging was performed in 21 patients with transposition of the great arteries (TGA). In the 13 patients with preoperative TGA, it was possible to differentiate TGA with the intact ventricular septum from TGA with associated anomalies such as patent ductus arteriosus or ventricular septal defect, and also TGA with pulmonary hypertension or pulmonary stenosis from TGA without them by evaluating the degree of thallium uptake in the free wall of the pulmonary ventricle (anatomical left ventricle). The degree of thallium uptake was well correlated with systolic pressure of the pulmonary ventricle (r = 0.98). In the 13 patients with postoperative TGA, it was less correlated with the pulmonary ventricular systolic pressure (r = 0.83). Four cases sequentially studied showed a marked decrease in thallium uptake in the pulmonary ventricle 10 to 16 months after Rastelli operation. But the corrected thallium uptake (thallium activity/ventricular systolic pressure) was more increased compared with the uptake of the systemic ventricle after the surgery. This was probably related to a decrease of the pressure load to the pulmonary ventricle following the surgery and to the fact that there should be some delay of a decrease of the ventricular mass. An increased lung uptake of thallium was noted in the cases of tricuspid regurgitation after Mustard operation, but the degree of regurgitation was not clearly correlated with the increase of thallium uptake in the lung. In five cases after Rastelli operation, one patient showed a high degree of thallium uptake of the pulmonary ventricle (anatomical right ventricle), and the conduit valve calcification and severe pulmonary stenosis were confirmed by cardiac catheterization and angiography. Thus myocardial imaging provides a reliable means for the qualitative and quantitative assessment of TGA before and after operation.

  1. PREOPERATIVE THERAPY OF LOW-DOSE ASPIRIN IN INTERNAL MAMMARY ARTERY BYPASS OPERATIONS WITH AND WITHOUT LOW-DOSE APROTININ

    NARCIS (Netherlands)

    SCHONBERGER, JPAM; BREDEE, JJ; VANOEVEREN, W; VANZUNDERT, AAJ; VERKROOST, M; TERWOORST, J; BAVINCK, JH; BERREKLOUW, E; WILDEVUUR, CRH

    1993-01-01

    The effect of preoperative low-dose aspirin (1 mg/kg of body weight) and intraoperative low-dose aprotinin (2 million kallikrein inactivator units) treatment on perioperative blood loss and blood requirements in patients who undergo internal mammary artery bypass operations is unknown. Therefore, we

  2. Splenic artery embolisation in the non-operative management of blunt splenic trauma in adults

    Directory of Open Access Journals (Sweden)

    Richard J. Cormack

    2016-03-01

    Full Text Available Background: The purpose of this study was to evaluate the splenic salvage rate with angioembolisation in the non-operative management (NOM of blunt splenic injury.Methods: We conducted a retrospective analysis of patients presenting to our Level I trauma centre with computed tomography (CT-confirmed splenic injury following blunt trauma and in whom angioembolisation was utilised in the algorithm of NOM. Data review included CT and angiography findings, embolisation technique and patient outcomes.Results: Between January 2005 and April 2010, 60 patients with splenic injury following blunt trauma underwent NOM, which included splenic artery embolisation (SAE. All patients included in the study required a preadmission. CT scan was used to document the American Association for the Surgery of Trauma (AAST grade of splenic injury. The average injury grade was 3.0. The non-operative splenic salvage rate following SAE was 96.7% with statistically similar salvage rates achieved for grades II to IV injuries. The quantity of haemoperitoneum and the presence of a splenic vascular injury did not significantly affect the splenic salvage rate. The overall complication rate was 27%, of which 15% were minor and 13% were major.Conclusion: SAE is a safe and effective treatment strategy in the NOM of blunt splenic injury. The quantity of haemoperitoneum, the presence of vascular injury and embolisation technique did not significantly affect the splenic salvage rate.

  3. All-optical switching in a continuously operated and strongly coupled atom-cavity system

    CERN Document Server

    Dutta, Sourav

    2016-01-01

    We experimentally demonstrate collective strong coupling, optical bi-stability (OB) and all-optical switching in a system consisting of ultracold 85Rb atoms, trapped in a dark magneto-optical trap (DMOT), coupled to an optical Fabry-Perot cavity. The strong coupling is established by measuring the vacuum Rabi splitting (VRS) of a weak on-axis probe beam. The dependence of VRS on the probe beam power is measured and bi-stability in the cavity transmission is observed. We demonstrate control over the transmission of the probe beam through the atom-cavity system using a free-space off-axis control beam and show that the cavity transmission can be switched on and off in micro-second timescales using micro-Watt control powers. The utility of the system as a tool for sensitive, in-situ and rapid measurements is envisaged.

  4. Performance optimization of optical switches in ferroelectric liquid crystals and polymers operating at 1550 nm

    Science.gov (United States)

    Asquini, Rita; Gizzi, Claudio; Beccherelli, Romeo; d'Alessandro, Antonio

    2004-01-01

    A multilayer structure realizing an optical switch with ferroelectric liquid crystal, polymeric buffers and waveguides has been analyzed at the wavelength of 1550 nm, focusing on fabrication and design tolerances. The used liquid crystal FELIX-M4851-025 from Clariant is aligned by Nylon6 and embedded between two polymeric waveguides. ITO is deposited on quartz substrates to apply voltage to the cell and polymeric buffers are employed to reduce ITO absorption losses. The polymers consisted of poly(pentafluorostyrene-co-glycidyl methacrylate). Light is switched between the optical waveguides by reorienting the liquid crystal. Optimization in terms of optical losses and extinction ratios was carried out by varying layer thicknesses, refractive indices of waveguides and buffers, and the angle α between the normal to the smectic layers and the propagation direction. An optimized device with α = 51°, refractive indices of 1.475 and 1.462, thicknesses of 3 and 6 μm for waveguides and buffer, respectively and 4.4 μm for the liquid crystal layer, exhibits an extinction ratio of 59.6 dB with losses as low as 0.8 dB for a length of only 174 μm. A device design using single mode channel waveguides for optical switching matrices has been also carried out.

  5. Improved operation of a microwave pulse compressor with a laser-triggered high-pressure gas plasma switch

    Science.gov (United States)

    Shlapakovski, A.; Gorev, S.; Krasik, Ya. E.

    2016-08-01

    The influence of laser beam parameters on the output pulses of a resonant microwave compressor with a laser-triggered plasma switch was investigated. The S-band compressor, consisting of a rectangular waveguide-based cavity and H-plane waveguide tee with a shorted side arm, was filled with pressurized dry air and pumped by 1.8-μs-long microwave pulses of up to 450 kW power. A Nd:YAG laser was used to ignite the gas discharge in the tee side arm for output pulse extraction. The laser beam (at 213 nm or 532 nm) was directed along the RF electric field lines. It was found that the compressor operated most effectively when the laser beam was focused at the center of the switch waveguide cross-section. In this case, the power extraction efficiency reached ˜47% at an output power of ˜14 MW, while when the laser beam was not focused the maximal extraction efficiency was only ˜20% at ˜6 MW output power. Focusing the laser beam resulted also in a dramatic decrease (down to switch, and the jitter of the output pulses' appearance was minimized. In addition, the quality of the output pulses' waveform was significantly improved.

  6. Q-switched thulium-doped fibre laser operating at 1900 nm using multi-walled carbon nanotubes saturable absorber

    Directory of Open Access Journals (Sweden)

    Norazlina Saidin

    2014-06-01

    Full Text Available Simple, low-cost and stable passive Q-switched thulium-doped fibre lasers (TDFLs operating at 1892.4 and 1910.8 nm are demonstrated using 802 and 1552 nm pumping schemes, respectively, in conjunction with a multi-walled carbon nanotubes (MWCNTs saturable absorber (SA. The MWCNTs composite is prepared by mixing the MWCNTs homogeneous solution into a dilute polyvinyl alcohol (PVA polymer solution before it is left to dry at room temperature to produce thin film. Then the film is sandwiched between two FC/PC fibre connectors and integrated into the laser cavity for Q-switching pulse generation. The pulse repetition rate of the TDFL configured with 802 nm pump can be tuned from 3.8 to 4.6 kHz, whereas the corresponding pulse width reduces from 22.1 to 18.3 μs as the pump power is increased from 187.3 to 194.2 mW. On the other hand, with 1552 nm pumping, the TDFL generates optical pulse train with a repetition rate ranging from 13.1 to 21.7 kHz with a pulse width of 11.5–7.9 μs when the pump power is tuned from 302.2 to 382.1 mW. A higher performance Q-switched TDFL is expected to be achieved with the optimisation of the MWCNT-SA saturable absorber and laser cavity.

  7. Theoretical Analysis on the Simultaneous Operation of a Color-Center Laser and a Q-Switched Nd: YAG Laser

    Institute of Scientific and Technical Information of China (English)

    WU Xing; DING Yongkui; ZHANG Rui

    2000-01-01

    The simultaneous operation for the Q- switched Nd: YAG laser at 1.06 and the tunable color-center laser over 1.12~1.26 μm has been realized by using a LiF: F2- color-center crystal both as the Q-switcher for the Nd:YAG laser and as the active medium for the color-center laser. The interaction of the two lasers has been analyzed and calculated with the rate equations. The pulse duration of YAG laser is compressed, in agreement with the experimental results.

  8. Switching Operation Simulations in a Large Offshore Wind Farm with Use of Parametric Variation and Frequency Domain Severity Factor

    DEFF Research Database (Denmark)

    Holdyk, Andrzej; Holbøll, Joachim; Arana, Ivan;

    2012-01-01

    Transient voltages resulting from switching operations depend on an interaction between the breaker, the transformer, cables and a neighbourhood grid and imply a risk for the transformer and other components. In this paper the Frequency Domain Severity Factor (FDSF) is used to assess the severity...... implemented in ATP-EMTP using standard component models and further validated against measurements. The results show the range of overvoltages on the transformer terminals as well as the corresponding FSDF for all turbines under a number of varying parameters. The maximum FDSF of 1.235 and frequency of 445 k...

  9. Arterial desaturation due to pulmonary arteriovenous malformations after the Kawashima Operation

    Directory of Open Access Journals (Sweden)

    Rohit S Loomba

    2016-01-01

    Full Text Available Arterial desaturation may occur after the Kawashima procedure and, in the absence of venovenous collaterals is usually due to pulmonary arteriovenous malformations. Stenting of the pulmonary arteries, oxygen therapy, and pulmonary vasodilators such as sildenafil have not been able to resolve the arterial desaturation and the only way to do this has been Fontan completion. The time course of the formation of these malformations after the Kawashima and the progression of cyanosis and its resolution after the Fontan has only been demonstrated in case reports and small case series. We pool the available data to model arterial saturations in patients with pulmonary arteriovenous malformations after the Kawashima procedure.

  10. Aldosterone Inactivates the Endothelin-B Receptor via a Cysteinyl Thiol Redox Switch to Decrease Pulmonary Endothelial Nitric Oxide Levels and Modulate Pulmonary Arterial Hypertension

    Science.gov (United States)

    Maron, Bradley A.; Zhang, Ying-Yi; White, Kevin; Chan, Stephen Y.; Handy, Diane E.; Mahoney, Christopher E.; Loscalzo, Joseph; Leopold, Jane A.

    2012-01-01

    Background Pulmonary arterial hypertension (PAH) is characterized, in part, by decreased endothelial nitric oxide (NO•) production and elevated levels of endothelin-1. Endothelin-1 is known to stimulate endothelial nitric oxide synthase (eNOS) via the endothelin-B receptor (ETB), suggesting that this signaling pathway is perturbed in PAH. Endothelin-1 also stimulates adrenal aldosterone synthesis; in systemic blood vessels, hyperaldosteronism induces vascular dysfunction by increasing endothelial reactive oxygen species (ROS) generation and decreasing NO• levels. We hypothesized that aldosterone modulates PAH by disrupting ETB-eNOS signaling through a mechanism involving increased pulmonary endothelial oxidant stress. Methods and Results In rats with PAH, elevated endothelin-1 levels were associated with elevated aldosterone levels in plasma and lung tissue and decreased lung NO• metabolites in the absence of left heart failure. In human pulmonary artery endothelial cells (HPAECs), endothelin-1 increased aldosterone levels via PGC-1α/steroidogenesis factor-1-dependent upregulation of aldosterone synthase. Aldosterone also increased ROS production, which oxidatively modified cysteinyl thiols in the eNOS-activating region of ETB to decrease endothelin-1-stimulated eNOS activity. Substitution of ETB-Cys405 with alanine improved ETB-dependent NO• synthesis under conditions of oxidant stress, confirming that Cys405 is a redox sensitive thiol that is necessary for ETB-eNOS signaling. In HPAECs, mineralocorticoid receptor antagonism with spironolactone decreased aldosterone-mediated ROS generation and restored ETB-dependent NO• production. Spironolactone or eplerenone prevented or reversed pulmonary vascular remodeling and improved cardiopulmonary hemodynamics in two animal models of PAH in vivo. Conclusions Our findings demonstrate that aldosterone modulates an ETB cysteinyl thiol redox switch to decrease pulmonary endothelium-derived NO• and promote PAH

  11. Intra-operative Hemostasis of Punctured Femoral Artery Using HIFU: A Survival Study

    Science.gov (United States)

    Zderic, Vesna; Keshavarzi, Amid; Noble, Misty L.; Paun, Marla; Sharar, Sam R.; Crum, Lawrence A.; Martin, Roy W.; Vaezy, Shahram

    2005-03-01

    The objective was to investigate the long-term efficacy of hemostasis and healing of arteries after HIFU application. The femoral arteries of 22 adult rabbits were surgically exposed. Fifteen arteries were punctured with a needle and treated with HIFU, and 7 arteries were sham-treated (no puncture or HIFU was applied). The tip of the HIFU applicator was positioned on the bleeding site, and HIFU energy was applied until hemostasis was achieved. The focal intensity was approximately 3,000 W/cm2, at the resonant frequency of 9.6 MHz. Serial ultrasound images, blood and tissue samples were collected immediately and on days 1, 3, 7, 14, 28, and 60 after the treatment. Eleven of the arteries were patent after the treatment, and four arteries were occluded, as confirmed using Doppler imaging. One of the occluded arteries reopened at day 14. HIFU exposure time to achieve hemostasis was 27 ±17 seconds for patent arteries and 101±38 seconds for the occluded arteries. The blood flow velocities were not statistically different between HIFU-treated patent vessels and sham-treated vessels. The tunica adventitia and media, disrupted and coagulated immediately after the treatment, recovered to normal appearance within 28 days, with localized thinning of the tunica media observed up to day 60. Neo-intimal hyperplasia was observed in the arteries at days 14 and 28. HIFU produced an effective and long-term (up to 60 days) hemostasis of injured femoral arteries while preserving a normal blood flow and vessel wall structure in the majority of vessels.

  12. [Incidentally detected bronchial artery aneurysm with combined operation for mitral regurgitation;report of a case].

    Science.gov (United States)

    Sato, Hisashi; Oteki, Hitoshi; Naito, Kozo; Yunoki, Junji

    2015-02-01

    A 77-year-old woman was admitted to the hospital for heart failure with orthopnea. Echocardiography revealed massive mitral regurgitation. During preoperative cardiac catheterization, an aneurysm was indentified incidentally just below the tracheal carina. Three dimensional computed tomography showed three bronchial artery aneurysms behind the pulmonary artery and the left atrium. The proximal aneurysm was the largest and was 22 mm in diameter. It was resected by retracting the ascending aorta to the left, the superior vana cava to the right and right pulmonary artery cranially under cardiopulmonary bypass, and mitral valve plasty was performed. We believed that resection of the proximal aneurysm would cause thrombotic occlusion of the other 2 aneurysms. Bronchial artery aneurysm is a rare entity that is observed in fewer than 1% of those who undergo selective bronchial arteriography. In addition, because bronchial artery aneurysm is a potentially life-threatening lesion, it should be treated promptly when diagnosed.

  13. Post-Operative hemorrhage after myomectomy: Safety and efficacy of transcatheter uterine artery embolization

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Alvin Yu Hon [Dept. of Radiology, Pamela Youde Nethersole Eastern Hospital, Hong Kong (China); Shin, Ji Hoon; Yoon, Hyun Ki; Ko, Gi Young; Park, Sang Gik [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Seong, Nak Jong; Yoon, Chang Jin [Dept. of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of)

    2014-06-15

    To evaluate the safety and clinical efficacy of transcatheter uterine artery embolization (UAE) for post-myomectomy hemorrhage. We identified eight female patients (age ranged from 29 to 51 years and with a median age of 37) in two regional hospitals who suffered from post-myomectomy hemorrhage requiring UAE during the time period from 2004 to 2012. A retrospective review of the patients' clinical data, uterine artery angiographic findings, embolization details, and clinical outcomes was conducted. The pelvic angiography findings were as follows: hypervascular staining without bleeding focus (n = 5); active contrast extravasation from the uterine artery (n = 2); and pseudoaneurysm in the uterus (n = 1). Gelatin sponge particle was used in bilateral uterine arteries of all eight patients, acting as an empirical or therapeutic embolization agent for the various angiographic findings. N-butyl-2-cyanoacrylate was administered to the target bleeding uterine arteries in the two patients with active contrast extravasation. Technical and clinical success were achieved in all patients (100%) with bleeding cessation and no further related surgical intervention or embolization procedure was required for hemorrhage control. Uterine artery dissection occurred in one patient as a minor complication. Normal menstrual cycles were restored in all patients. Uterine artery embolization is a safe, minimally invasive, and effective management option for controlling post-myomectomy hemorrhage without the need for hysterectomy.

  14. Q-Switched Operation with Carbon-Based Saturable Absorbers in a Nd:YLF Laser

    Directory of Open Access Journals (Sweden)

    Rosa Weigand

    2015-09-01

    Full Text Available We have numerically studied the influence of the absorption modulation depth of carbon-based saturable absorbers (graphene and carbon nanotubes (CNTs on the Q-switched regime of a diode-pumped Nd:YLF laser. A short-length cavity was used with an end mirror on which CNTs or mono- or bi-layer graphene were deposited, forming a saturable absorber mirror (SAM. Using a standard model, the generated energy per pulse was calculated, as well as the pulse duration and repetition rate. The results show that absorbers with higher modulation depths, i.e., graphene, deliver higher energy pulses at lower repetition rates. However, the pulse duration did not have a monotonic behavior and reaches a minimum for a given low value of the modulation depth typical of CNTs.

  15. Balloon catheterization for hemostasis during the operation of ruptured femoral artery pseudoaneurysm

    Institute of Scientific and Technical Information of China (English)

    SHI De-bing; FU Wei-guo; WANG Yu-qi; GUO Da-qiao; CHEN Bin; SHI Zhen-yu

    2007-01-01

    @@ Pseudoaneurysms of the femoral artery usually progress and can rupture if left untreated. Therefore,intraoperative hemostasis is of the paramount importance in the management of these emergent situations,especially for the patients with poor general health.

  16. Transvenous cardiac resynchronization therapy in complex congenital heart diseases: dextrocardia with transposition of the great arteries after Mustard operation.

    Science.gov (United States)

    Zartner, Peter A; Wiebe, Walter; Volkmer, Marius; Thomas, Daniel; Schneider, Martin

    2009-04-01

    Cardiac resynchronization therapy revealed first promising results in patients with a congenital heart disease and a systemic right ventricle. Contrast-enhanced magnetic resonance imaging showed accessibility of the coronary sinus in an 18-year-old male patient with mirror dextrocardia, d-transposition of the great arteries and ventricular septal defect (VSD) after Mustard operation and VSD patch closure. In literatures, transvenous lead placement is discussed in this anatomical setting, with opposed position of the ventricular leads and reliable lead characteristics.

  17. Comprehensive tests of artificial viscosities, their switches and derivative operators used in Smoothed Particle Hydrodynamics

    CERN Document Server

    Hosono, Natsuki; Makino, Junichiro

    2016-01-01

    Hydrodynamical simulations of rotating disk play important roles in the field of astrophysical and planetary science. Smoothed Particle Hydrodynamics (SPH) has been widely used for such simulations. It, however, has been known that with SPH, a cold and thin Kepler disk breaks up due to the unwanted angular momentum transfer. Two possible reasons have been suggested for this breaking up of the disk; the artificial viscosity (AV) and the numerical error in the evaluation of pressure gradient in SPH. Which one is dominant has been still unclear. In this paper, we investigate the reason for this rapid breaking up of the disk. We implemented most of popular formulations of AV and switches and measured the angular momentum transfer due to both AV and the error of SPH estimate of pressure gradient. We found that the angular momentum transfer due to AV at the inner edge triggers the breaking up of the disk. We also found that the classical von-Neumann-Richtmyer-Landshoff type AV with a high order estimate for $\

  18. Flow Characterization of Severe Carotid Artery Stenosis in Pre- and Post-operative Phantoms by Using Magnetic Resonance Velocimetry

    Science.gov (United States)

    Ko, Seungbin; Song, Simon; Kim, Doosang

    2016-11-01

    It is remained unknown that the flow characteristics changes between pre- and post-operative severe carotid artery stenosis could affect the long-term patency or failure. However, in-vivo clinical experiments to uncover the flow details are far from bed-side due to limited measurement resolutions, blurring artifact, etc. We studied detailed flow characteristics of more than 75% severe carotid artery stenosis before and after surgical treatments. Real-size flow phantoms for 10 patients, who underwent carotid endarterectomy with patch/no patch closure, were prepared by using a 3D rapid-prototype machine from CT scanned images. The working fluid is a glycerin aqueous solution, and patient-specific pulsatile flows were applied to the phantoms, based on ultrasonic flow rate measurements. The flows were visualized with magnetic resonance velocimetry (MRV). The detailed flow characteristics are presented for both pre- and post-operative carotid arteries along with visualization data of 3 dimensional, 3 component velocity fields. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 2016R1A2B3009541).

  19. Immediate incubation of blood cultures outside routine laboratory hours of operation accelerates antibiotic switching

    NARCIS (Netherlands)

    J.J. Kerremans (Jos); A.K. van der Bij (Akke); W.H.F. Goessens (Wil); H.A. Verbrugh (Henri); M.C. Vos (Margreet)

    2009-01-01

    textabstractThe aim of this prospective randomized controlled clinical trial was to assess the impact of immediate incubation of blood cultures delivered to the laboratory outside its hours of operation on turnaround times, antibiotic prescription practices, and patient outcomes. A continuously moni

  20. Temporal system-level organization of the switch from glycolytic to gluconeogenic operation in yeast

    NARCIS (Netherlands)

    Zampar, Guillermo G; Kümmel, Anne; Ewald, Jennifer; Jol, Stefan; Niebel, Bastian; Picotti, Paola; Aebersold, Ruedi; Sauer, Uwe; Zamboni, Nicola; Heinemann, Matthias

    2013-01-01

    The diauxic shift in Saccharomyces cerevisiae is an ideal model to study how eukaryotic cells readjust their metabolism from glycolytic to gluconeogenic operation. In this work, we generated time-resolved physiological data, quantitative metabolome (69 intracellular metabolites) and proteome (72 enz

  1. Serum lactate as a prognostic factor in coronary artery bypass graft operation by on pump method

    OpenAIRE

    Jabbari, Ali; Banihashem, Nadia; Alijanpour, Ebrahim; Vafaey, Hamid Reza; Alereza, Hakimeh; Rabiee, Seyed Mozafar

    2013-01-01

    Background: Lactic acidosis in cardiac surgical patients is a manifestation of systemic inflammation and excess pro-inflammatory cytokine production. This investigation was designed to integrate basic concepts about lactate acidosis with a clinically used of serum lactate in patients under coronary artery bypass surgery (CABG) by on pump method.

  2. Use of a Proximity Sensor Switch for "Hands Free" Operation of Computer-Based Video Prompting by Young Adults with Moderate Intellectual Disability

    Science.gov (United States)

    Ivey, Alexandria N.; Mechling, Linda C.; Spencer, Galen P.

    2015-01-01

    In this study, the effectiveness of a "hands free" approach for operating video prompts to complete multi-step tasks was measured. Students advanced the video prompts by using a motion (hand wave) over a proximity sensor switch. Three young adult females with a diagnosis of moderate intellectual disability participated in the study.…

  3. Speed-variable Switched Differential Pump System for Direct Operation of Hydraulic Cylinders

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Roemer, Daniel Beck; Pedersen, Henrik Clemmensen

    2015-01-01

    proportional valves, this design allows to control the lower chamber pressure levels, throttling excess compression flow to tank. The resulting design introduces additional losses due to throttling of excess compression flow, but also improves the dynamic properties of the system significantly. The proposed...... gear pumps, the throttling losses are confined to cross port leakage in the cylinder and leakage of the pumps. However, it turns out that the volumetric pump losses and the pressure dynamics of the cylinder and connecting pipes may cause pressure increase- or decrease in the cylinder chambers, which...... may seriously influence the dynamics and hence the performance during operation. This paper presents an analysis of these properties, and a redesign of the hydraulic system concept is proposed. Here the area- and displacement ratios are deliberately mismatched, causing inherent pressure build...

  4. A systematic review of pre-operative predictors of post-operative depression and anxiety in individuals who have undergone coronary artery bypass graft surgery.

    Science.gov (United States)

    McKenzie, Louise H; Simpson, Jane; Stewart, Marie

    2010-01-01

    In addition to the physical benefits, another important objective of coronary artery bypass graft (CABG) surgery is improvement of health-related quality of life. The aim of this systematic review is to provide an overview of the literature relating to the pre-operative prediction of post-operative depression and anxiety in individuals who have undergone CABG surgery. Forty-six studies were identified through a literature search of electronic databases conducted using explicit inclusion and exclusion criteria. The study characteristics, methodological features, and psychometric and clinical outcomes were summarised in a systematic manner. Collective appraisal of the studies indicated that symptoms of depression and anxiety exhibited after CABG surgery are best predicted by pre-operative measures of functioning in that area. Papers were inconclusive with respect to the predictive qualities of gender and age. Further research is required to clarify the predictive values of these and other factors, including pre-morbid ill health and socio-economic status. The findings of this review indicate a range of pre-operative predictors of post-operative depression and anxiety in patients with CABG. Chief among these are pre-operative depression and anxiety. These findings have clinical implications concerning the importance of pre and post-operative psychological assessment and intervention for individuals at risk of poor psychological recovery.

  5. The role of the Fontan operation in the treatment of congenitally corrected transposition of the great arteries

    Directory of Open Access Journals (Sweden)

    Tom R Karl

    2011-01-01

    Full Text Available Congenitally corrected transposition of the great arteries (ccTGA is a complex cardiac anomaly with an unfavorable natural history. Surgical treatment has been available for over 50 years. Initial procedures used for ccTGA did not correct atrio-ventricular discordance, leaving the right ventricle in systemic position. In the past two decades anatomic repair has been considered to be a better option. Many cases subjected to anatomic repairs would also be suitable for the Fontan strategy, which probably has a lower initial risk. The rationale for use of the Fontan operation in management of congenitally corrected transposition is discussed in this review, with comparisons to other strategies.

  6. Mechanically exfoliated black phosphorus as a new saturable absorber for both Q-switching and Mode-locking laser operation.

    Science.gov (United States)

    Chen, Yu; Jiang, Guobao; Chen, Shuqing; Guo, Zhinan; Yu, Xuefeng; Zhao, Chujun; Zhang, Han; Bao, Qiaoliang; Wen, Shuangchun; Tang, Dingyuan; Fan, Dianyuan

    2015-05-18

    Black phosphorus (BP), an emerging narrow direct band-gap two-dimensional (2D) layered material that can fill the gap between the semi-metallic graphene and the wide-bandgap transition metal dichalcogenides (TMDs), had been experimentally found to exhibit the saturation of optical absorption if under strong light illumination. By taking advantage of this saturable absorption property, we could fabricate a new type of optical saturable absorber (SA) based on mechanically exfoliated BPs, and further demonstrate the applications for ultra-fast laser photonics. Based on the balanced synchronous twin-detector measurement method, we have characterized the saturable absorption property of the fabricated BP-SAs at the telecommunication band. By incorporating the BP-based SAs device into the all-fiber Erbium-doped fiber laser cavities, we are able to obtain either the passive Q-switching (with maximum pulse energy of 94.3 nJ) or the passive mode-locking operation (with pulse duration down to 946 fs). Our results show that BP could also be developed as an effective SA for pulsed fiber or solid-state lasers.

  7. Surgical management of peripheral arterial disease. Operative methods and results; Die chirurgische Behandlung der arteriellen Verschlusskrankheit. Operationsmethoden und Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Wulff, B.; Jungbluth, T.; Esnaashari, H.; Franke, C.; Bruch, H.P. [Universitaetsklinikum Schleswig-Holstein, Luebeck (Germany). Klinik fuer Chirurgie

    2006-11-15

    Various operative and interventional methods are available to treat patients with peripheral arterial disease (PAD). The selection of the appropriate therapy should be made after a careful review of the patient's general condition, the morphology of the arterial occlusion, the risk of possible complications, and the likelihood of long-term success for each type of treatment. The different procedures complement one another in their technical possibilities and their risk profile The combination of surgical and interventional methods offers new therapeutic possibilities. The different surgical procedures and their long-term outcome are presented in this publication. (orig.) [German] Zur invasiven Therapie der arteriellen Verschlusskrankheit (AVK) stehen verschiedene operative und interventionelle Behandlungsformen zur Verfuegung. Die Auswahl der geeigneten Methode richtet sich nach dem Allgemeinzustand des Patienten, der Morphologie des arteriellen Verschlusses, dem Komplikationsrisiko und der Erfolgswahrscheinlichkeit der jeweiligen Behandlung im Langzeitverlauf. Hierbei konkurrieren die verschiedenen Verfahren nur oberflaechlich betrachtet miteinander, sie ergaenzen sich in ihren jeweiligen technischen Moeglichkeiten und dem Risikoprofil. Die Kombination chirurgischer und interventioneller Methoden bietet neue Behandlungsoptionen. Im Rahmen dieses Artikels werden die verschiedenen Operationsverfahren und deren Ergebnisse dargestellt. (orig.)

  8. Importance of maintaining left gastric arterial flow at Appleby operation preserving whole stomach for central pancreatic cancer.

    Science.gov (United States)

    Kimura, Akifumi; Yamamoto, Junji; Aosasa, Suefumi; Hatsuse, Kazuo; Nishikawa, Makoto; Nishiyama, Kiyoshi; Tsujimoto, Hironori; Moriya, Tomoyuki; Hase, Kazuo; Shinmoto, Hiroshi; Kaji, Tatsumi

    2012-01-01

    The safety of whole stomach-preserving Appleby operation with resection of the left gastric artery (LGA) for pancreatic cancer cannot be assured. The anatomy of the celiac axis (CA) with special regard to the position of the origin of the LGA was examined. Using 3D images of the vascular architecture reconstructed from volume data of helical CT, the length of the CA and the position of the origin of the LGA from the CA were measured in 53 patients. Among 53 patients, 47 patients (89%) had classical anatomy of the CA branches. The mean length(2 standard deviation) of the CA and the distance from the root of the LGA to the bifurcation of the CA were 25.2mm (-4.9) (range 14.6-36.5) and 10.3mm (+4.5)(range 2.4-21.9), respectively. In 23 (45%) cases, the LGA arose farther than 10mm away from the bifurcation of the CA. Among six patients with anatomical variation of the arteries, two (4%) had the LGA directly arising from the aorta. Conservation of the LGA at modified Appleby operation would give complete cancer removal by en bloc resection of the nerve plexus, without risk of ischemic complications of the stomach and liver.

  9. Optical packet switched networks

    DEFF Research Database (Denmark)

    Hansen, Peter Bukhave

    1999-01-01

    Optical packet switched networks are investigated with emphasis on the performance of the packet switch blocks. Initially, the network context of the optical packet switched network is described showing that a packet network will provide transparency, flexibility and bridge the granularity gap...... between the electrical switched layer and the WDM transport layer. Analytical models are implemented to determine the signal quality ghrough the switch blocks in terms of power penalty and to assess the traffic performance of different switch block architectures. Further, a computer simulation model...... is used to investigate the influence on the traffic performance of asynchronous operation of the switch blocks. The signal quality investigation illustrates some of the component requirements in respect to gain saturation in SOA gates and crosstalk in order to obtain high cascadability of the switch...

  10. Resistance switching memory operation using the bistability in current-voltage characteristics of GaN/AlN resonant tunneling diodes

    Science.gov (United States)

    Nagase, Masanori; Takahashi, Tokio; Shimizu, Mitsuaki

    2016-10-01

    Resistance switching memory operations using the bistability in the current-voltage (I-V) characteristics of GaN/AlN resonant tunneling diodes (RTDs) were investigated to realize an ultrafast nonvolatile memory operating at a picosecond time scale. Resistance switching memory operations based on electron accumulation due to intersubband transitions and electron release due to tunneling current were demonstrated with high reproducibility at room temperature when the leakage of electrons accumulating in the quantum well from the deep level in the AlN barrier was suppressed. A nonvolatile memory for the processor core in a normally off computing system is expected to be realized using the bistability in the I-V characteristics of GaN/AlN RTDs.

  11. Pre-operative endostent placement to allow the complete and safe resection of a recurrent tumor that had tightly adhered to the subclavian artery: A case report

    Directory of Open Access Journals (Sweden)

    Takuya Nakayama

    2015-04-01

    Full Text Available Radiation and tumor infiltration confer a high risk of bleeding on surgical removal of tumor. We report on the case of a 42-year-old woman with a recurrent occult subclavian tumor in her right breast. Computed tomography revealed enhanced tumor adhesion to the subclavian artery at the infraclavicular lymph node. No other metastases were detected. We pre-operatively performed stenting of the right subclavian artery, and the tumor was resected completely and safely.

  12. The study of neuropsychological alterations following coronary artery bypass operation as predicted by computed tomography scan of the brain

    Energy Technology Data Exchange (ETDEWEB)

    Iguchi, Atsushi; Sato, Kiyoharu (Sendai Tokushu-kai Hospital (Japan)); Sadahiro, Mitsuaki; Endo, Masato; Yokoyama, Hitoshi; Ohmi, Mikio

    1993-01-01

    The objective of this clinical study is to provide information regarding the association between coexistent cerebrovascular disease and neuropsychological abnormalities after coronary artery bypass operations. Computed tomography scan of the brain was performed in 104 patients pre-operatively, and their post-operative neuropsychological functions were evaluated. The patients were categorized as follows according to the CT findings. Seventy-three patients showed normal or slight cerebral cortical atrophy which usually seen in patients over fifty of age (group A). Sixteen showed moderate or severe cortical atrophy (group B). Fifteen patients demonstrated the characteristic findings of Binswanger type; severe white matter hypodensity especially in frontal horns and dilated ventricles (group C). Overt neuropsychological dysfunction was not observed in patients in groups A and B. Six patients in group C showed a combination of dementia, bizarre behavior, disorientation and gait dyspraxia following bypass operations. The pseudobulbar signs were also found in 3 patients. These clinical abnormalities persisted for six days to three weeks, and were most often reversible. Although the underlying mechanism of these deleterious alterations is not elucidated, the ischemic nature of the characteristic white matter lesions was highly suspected. The arteriosclerotic changes of the arteriole of the cerebral cortex and hypoperfusion during cardio-pulmonary bypass were supposed to be responsible. Therefore it was concluded that special attention should be focused on neurological evaluation for bypass surgery in group C patients. (author).

  13. SPY: an innovative intra-operative imaging system to evaluate graft patency during off-pump coronary artery bypass grafting.

    Science.gov (United States)

    Takahashi, Masao; Ishikawa, Toshihiro; Higashidani, Koichi; Katoh, Hiroki

    2004-09-01

    Off-pump coronary artery bypass grafting (CABG) has been rapidly increased, because of its less invasiveness with low complications. However, graft patency rate highly depends on the operators' capability due to technical difficulties. The SPY system, based on the fluorescence of indocyanine green, is an innovative device that permits validation of graft patency intra-operatively. Real time images of grafts are obtained with no need for catheterization, X-rays or iodine contrast medium. High-quality images could be obtained in all 290 grafts of 72 off-pump CABG cases (mean 4.0 grafts per patient). Four anastomoses (1.4%), including two proximal and two distal, were revised because of defects detected by SPY images. In one case, the SPY system revealed no blood flow in a radial sequential graft, although transit-time flow meter measurements showed a diastolic dominant pattern. SPY images provide critical information to surgeons to detect non-patent grafts, allowing them to be revised while the patient is still on the operating table. Using the SPY system, technical failures could be completely resolved during surgery. The use of the SPY system for intra-operative graft validation during off-pump CABG may become the gold standard for surgical management in the near future.

  14. Continuous-wave and Q-switched operation of a compact, diode-pumped Yb3+:KY(WO4)2 planar waveguide laser.

    Science.gov (United States)

    Bain, F M; Lagatsky, A A; Kurilchick, S V; Kisel, V E; Guretsky, S A; Luginets, A M; Kalanda, N A; Kolesova, I M; Kuleshov, N V; Sibbett, W; Brown, C T A

    2009-02-02

    A diode-pumped LPE-grown Yb:KYW planar waveguide laser is demonstrated in a microchip monolithic cavity configuration. Output powers as high as 148 mW and thresholds as low as 40 mW were demonstrated during continuous-wave operation. Pulses of 170 ns duration with maximum pulse energy of 44 nJ at a 722 kHz repetition rate were generated when Q-switched using a semiconductor saturable absorber mirror.

  15. Efficacy of post-operative clopidogrel treatment in patients revascularized with coronary artery bypass grafting after myocardial infarction

    DEFF Research Database (Denmark)

    Sørensen, Rikke; Abildstrøm, Steen Z; Hansen, Peter R

    2011-01-01

    OBJECTIVES: The objective of this study was to examine the clinical efficacy of clopidogrel treatment on death and recurrent myocardial infarction (MI) among MI patients revascularized by coronary artery bypass graft surgery (CABG). BACKGROUND: The benefit from post-operative clopidogrel in CABG......-treated MI patients is largely unknown. METHODS: All patients admitted with first-time MI between 2002 and 2006, treated with CABG within 180 days after admission, were identified by nationwide administrative registers. Clopidogrel treatment was determined by claimed prescriptions after discharge from...... surgery. Risk of death or recurrent MI, and of a combined end point of the 2, were assessed by cumulative incidence and Cox proportional hazards model. A propensity score-matched subgroup analysis was done. RESULTS: We included 3,545 patients, and of these, 957 (27.0%) were treated with clopidogrel after...

  16. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-08-01

    We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

  17. Severe primary postpartum hemorrhage due to genital tract laceration after operative vaginal delivery: successful treatment with transcatheter arterial embolization

    Energy Technology Data Exchange (ETDEWEB)

    Fargeaudou, Yann; Soyer, Philippe; Sirol, Marc; Dref, Olivier le; Boudiaf, Mourad; Dahan, Henri; Rymer, Roland [Hopital Lariboisiere-APHP-GHU Nord et Universite Diderot-Paris 7, Department of Abdominal and Interventional Imaging, Paris (France); Morel, Olivier [Hopital Lariboisiere-APHP-GHU Nord et Universite Diderot-Paris 7, Department of Obstetrics, Paris (France)

    2009-09-15

    The purpose of this study was to report our experience in the management of severe primary postpartum hemorrhage due to genital tract laceration following operative vaginal delivery with forceps using pelvic transcatheter arterial embolization (TAE). Ten women (mean age, 31.9 years) with severe primary postpartum hemorrhage due to genital tract laceration after operative delivery with forceps were treated with TAE. TAE was indicated because of intractable bleeding that could not be controlled with uterotonic drugs, blood transfusion, attempted suturing and packing in all patients. Postdelivery perineal examination showed cervical or vaginal tears in all women and associated paravaginal hematoma in four. Angiography revealed extravasation of contrast material in six patients. TAE performed with gelatin sponge allowed to control the bleeding in all patients. Cervical and vaginal suturing was made possible and successfully achieved in the six women who had failed suturing attempts before TAE. Paravaginal hematoma was successfully evacuated in four patients in whom it was present after TAE. No complications related to TAE were noted. We conclude that in women with severe primary postpartum hemorrhage due to genital tract laceration after operative delivery with forceps, TAE is effective and safe for stopping the bleeding and helps genital tract suturing and evacuation of hematoma. (orig.)

  18. Research Progress on Multimode Interference Switches

    Institute of Scientific and Technical Information of China (English)

    GAO Qing; SHENG Zhi-rui; JIANG Xiao-qing; WANG Ming-hua

    2005-01-01

    Optical switches are key components for constructing optical communication networks, so it is necessary to design optical switches and optical switch arrays with high performance and low cost. As one type of optical switches, the multimode interference(MMI) switches have received considerable attention due to their unique merits. The structures and operation principles of various types of MMI switches are introduced,and the recent progresses of MMI switches are also discussed.

  19. Atomic Scale Plasmonic Switch

    OpenAIRE

    Emboras, A.; Niegemann, J.; Ma, P.; Haffner, C; Pedersen, A.; Luisier, M.; Hafner, C.; Schimmel, T.; Leuthold, J.

    2016-01-01

    The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocat...

  20. Special requisites for ground switch operation of parallel circuits of strongly connected transmission lines; Requisitos especiais de manobra para chaves de terra de circuitos paralelos de linhas de transmissao fortemente acoplados

    Energy Technology Data Exchange (ETDEWEB)

    Amon Filho, J.; Kastrup Filho, O.; Franca, W.J. [FURNAS, Rio de Janeiro, RJ (Brazil)

    1993-12-31

    This work aims to present results of a qualitative and quantitative analysis of the problem concerning the ground switch turn off operation of transmission lines parallel circuits involving computer simulations and field tests, being such tests compared to standards and constant criteria of the technical specifications of such ground switches. The so far achieved conclusions indicate that the arc resistors installed in the ground switches have been satisfactory solving the problem of the interruption of induced currents by those ground switches. 7 refs., 2 figs., 3 tabs.

  1. Severe coronary artery disease in Chinese patients with abdominal aortic aneurysm: prevalence and impact on operative mortality

    Institute of Scientific and Technical Information of China (English)

    SUN Tao; CHENG Yu-tong; ZHANG Hong-ju; CHEN Shun-hua; ZHANG Dong-hua; HUANG Ji; ZHANG Jing-mei; LI Zhi-zhong

    2012-01-01

    Background Little is known about the prognosis of coronary artery disease (CAD) in Chinese patients with abdominal aortic aneurysm (AAA).The aim of this study was to evaluate the predictors of in-hospital all-cause mortality of severe CAD in Chinese patients who were hospitalized for AAAs.Methods From January 2003 to August 2009,368 patients were operated on for AAAs.The clinical characteristics were retrospectively collected.The primary outcome was the in-hospital all-cause mortality.The clinical risk factors were subjected to a multivariate analysis to determine the predictors of in-hospital all-cause mortality.Results During their hospitalization,23% (85/368) of the patients underwent coronary angiography,which revealed significant lesions in 93% (79/85) of the patients.In 25 cases,coronary artery bypass grafting (CABG) was performed before the AAA repair and in 16 cases of percutaneous coronary intervention (PCI) was performed.Ten patients with AAA alone died before discharge,and eight patients diagnosed with AAA combined with CAD died.There was no statistical difference in the postoperative death between the two groups.The logistic analysis showed that age >70 years and CAD (vessels ≥2) were the significant factors in predicting the adverse clinical outcome.Conclusions The prevalence of severe CAD in Chinese patients with AAAs seemed lower than those that were reported.Myocardial evaluation and subsequent revascularization before AAA surgery could improve the clinical outcome for these patients who have severe CAD.

  2. Depression, C-reactive protein and length of post-operative hospital stay in coronary artery bypass graft surgery patients.

    Science.gov (United States)

    Poole, Lydia; Kidd, Tara; Leigh, Elizabeth; Ronaldson, Amy; Jahangiri, Marjan; Steptoe, Andrew

    2014-03-01

    This study aimed to explore the role of C-reactive protein (CRP) in mediating the association between greater pre-operative depression symptoms and longer post-operative length of stay in patients undergoing coronary artery bypass graft (CABG) surgery. We used a sample of 145 elective CABG patients and measured depression symptoms using the Beck Depression Inventory (BDI) prior to surgery and collected baseline measures of CRP. Participants were followed up during their in-hospital stay to measure early (1-3 days post-surgery) and persistent (4-8 days post-surgery) CRP responses to surgery. We found that compared with participants with low depression symptoms, those with elevated depression symptoms (BDI>10) prior to CABG were at increased odds of a hospital stay of greater than one week (OR 3.51, 95% CI 1.415-8.693, p=0.007) and that greater persistent CRP responses mediated this association. Further work is needed to explore the exact physiological pathways through which depression and CRP interact to affect recovery in CABG patients.

  3. BiCMOS operational amplifier with precise and stable dc gain for high-frequency switched capacitor circuits

    Science.gov (United States)

    Baschirotto, A.; Alini, R.; Castello, R.

    1991-07-01

    A novel approach in the design of high-frequency switched capacitor (SC) circuits is presented. It is based on the use of simple and fast amplifiers with low but precisely controlled gain value. The effect of the precisely known and stable opamp gain is compensated for by changing the capacitor values during the synthesis of the SC cell. An example of an opamp with these features and the synthesis of a biquadratic filter based on this approach are given.

  4. Near-infrared laparoscopy for real-time intra-operative arterial and lymphatic perfusion imaging.

    LENUS (Irish Health Repository)

    Cahill, R A

    2012-02-01

    Multimodal laparoscopic imaging systems possessing the capability for extended spectrum irradiation and visualization within a unified camera system are now available to provide enhanced intracorporeal operative anatomic and dynamic perfusion assessment and potentially augmented patient outcome. While ultraviolet-range energies have limited penetration and hence are probably more useful for endoscopic mucosal interrogation, the near-infrared (NIR) spectrum is of greater potential utility for the purposes of examining inducible fluorescence in abdominopelvic tissue that can be achieved by administration of specific tracer agents, either directly into the circulation (e.g. for anastomotic perfusion assessment at the time of stapling) or into the lymphatic system (e.g. for lymph basin road-mapping and\\/or focussed target nodal assessment). This technology is also capable of supplementing anatomic recognition of the biliary system while implantable fibres can also be inserted intraoperatively for the purpose of safeguarding vital structures such as the oesphagus and ureters especially in difficult reoperations. It is likely that this technological capability will find a clear and common indication in colorectal specialist and general surgical departments worldwide in the near future.

  5. [Management of coronary artery disease in diabetic patients with lower limb critical ischaemia: assessment of operational risk, drug therapy and indications for interventions].

    Science.gov (United States)

    Dedov, I I; Kalashnikov, V Iu; Terekhin, S A; Melkozerov, K V

    2012-01-01

    Despite obvious progress in management of diabetes mellitus, the DM-related complications rate remains inadmissibly high. Macroangiopathy is known to rank first amongst complications of diabetes mellitus, and coronary artery disease remains to be the major cause of death. Analysed herein are peculiarities of the clinical course in diabetic patients presenting with coronary artery disease and lower limb critical ischaemia, followed by discussing the issues concerning drug therapy, preoperative examination, and methods of diagnosis in this cohort of patients prior to vascular operations, assessment of the preoperative risk, indications for coronarography and myocardial revascularization. Also presented are the results of the main clinical trials dedicated to preoperative myocardial revascularization, including those in diabetic patients with limb critical ischaemia, and finally highlighting current importance of optimizing approaches to managing and working out algorithms of treatment policy for diabetic patients with a combination of coronary artery disease, diabetes mellitus, and critical limb ischaemia.

  6. Single Atom Plasmonic Switch

    CERN Document Server

    Emboras, Alexandros; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most - a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully i...

  7. New Insights into the Phage Genetic Switch: Effects of Bacteriophage Lambda Operator Mutations on DNA Looping and Regulation of PR, PL, and PRM.

    Science.gov (United States)

    Lewis, Dale E A; Gussin, Gary N; Adhya, Sankar

    2016-11-06

    One of the best understood systems in genetic regulatory biology is the so-called "genetic switch" that determines the choice the phage-encoded CI repressor binds cooperatively to tripartite operators, OL and OR, in a defined pattern, thus blocking the transcription at two lytic promoters, PL and PR, and auto-regulating the promoter, PRM, which directs CI synthesis by the prophage. Fine-tuning of the maintenance of lysogeny is facilitated by interactions between CI dimers bound to OR and OL through the formation of a loop by the intervening DNA segment. By using a purified in vitro transcription system, we have genetically dissected the roles of individual operator sites in the formation of the DNA loop and thus have gained several new and unexpected insights into the system. First, although both OR and OL are tripartite, the presence of only a single active CI binding site in one of the two operators is sufficient for DNA loop formation. Second, in PL, unlike in PR, the promoter distal operator site, OL3, is sufficient to directly repress PL. Third, DNA looping mediated by the formation of CI octamers arising through the interaction of pairs of dimers bound to adjacent operator sites in OR and OL does not require OR and OL to be aligned "in register", that is, CI bound to "out-of-register" sub-operators, for example, OL1~Ol2 and OR2~OR3, can also mediate loop formation. Finally, based on an examination of the mechanism of activation of PRM when only OR1 or OR2 are wild type, we hypothesize that RNA polymerase bound at PR interferes with DNA loop formation. Thus, the formation of DNA loops involves potential interactions between proteins bound at numerous cis-acting sites, which therefore very subtly contribute to the regulation of the "switch".

  8. Stable single-mode operation of injection-seeded Q-switched Nd:YAG laser by sine voltage modulation

    Institute of Scientific and Technical Information of China (English)

    Yongfei Gao; Junxuan Zhang; Huaguo Zang; Xiaolei Zhu; Yingjie Yu; Weibiao Chen

    2016-01-01

    Based on the modified ramp and fire technique,a novel injection seeding approach with real-time resonance tracking is successfully demonstrated in a single-frequency Nd:YAG pulsed laser.Appling a high-frequency sinusoidal modulation voltage to one piezo actuator and an adjustable DC voltage to another piezo actuator for active feedback,single-mode laser output with high-frequency stability is obtained,and the effect of the piezo hysteresis on the frequency stability can be eliminated for a laser diode pumped Q-switched Nd:YAG laser at a repetition rate of 400 Hz.

  9. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions

    Science.gov (United States)

    Pejov, Ljupčo; Petreska, Irina; Kocarev, Ljupčo

    2015-12-01

    A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a "quantum dot"), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1-014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1-245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green's function formalism, as well as by analysis of frontier molecular orbitals' behavior.

  10. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pejov, Ljupčo, E-mail: ljupcop@pmf.ukim.mk [Department of Physical Chemistry, Institute of Chemistry, SS. Cyril and Methodius University, Arhimedova 5, P.O. Box 162, 1001 Skopje, Republic of Macedonia (Macedonia, The Former Yugoslav Republic of); Petreska, Irina [Institute of Physics, Faculty of Natural Sciences and Mathematics, SS. Cyril and Methodius University, P.O. Box 162, 1001 Skopje, Republic of Macedonia (Macedonia, The Former Yugoslav Republic of); Kocarev, Ljupčo [Macedonian Academy of Sciences and Arts, Krste Misirkov 2, P.O. Box 428, 1000 Skopje, Republic of Macedonia (Macedonia, The Former Yugoslav Republic of); Faculty of Computer Science and Engineering, SS. Cyril and Methodius University, P.O. Box 393, 100 Skopje, Republic of Macedonia (Macedonia, The Former Yugoslav Republic of); BioCircuits Institute, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0402 (United States)

    2015-12-28

    A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a “quantum dot”), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1–014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1–245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green’s function formalism, as well as by analysis of frontier molecular orbitals’ behavior.

  11. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions.

    Science.gov (United States)

    Pejov, Ljupčo; Petreska, Irina; Kocarev, Ljupčo

    2015-12-28

    A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a "quantum dot"), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1-014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1-245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green's function formalism, as well as by analysis of frontier molecular orbitals' behavior.

  12. Numerical Study of the Dynamic Response of Heat and Mass Transfer to Operation Mode Switching of a Unitized Regenerative Fuel Cell

    Directory of Open Access Journals (Sweden)

    Hong Xiao

    2016-12-01

    Full Text Available Knowledge concerning the complicated changes of mass and heat transfer is desired to improve the performance and durability of unitized regenerative fuel cells (URFCs. In this study, a transient, non-isothermal, single-phase, and multi-physics mathematical model for a URFC based on the proton exchange membrane is generated to investigate transient responses in the process of operation mode switching from fuel cell (FC to electrolysis cell (EC. Various heat generation mechanisms, including Joule heat, reaction heat, and the heat attributed to activation polarizations, have been considered in the transient model coupled with electrochemical reaction and mass transfer in porous electrodes. The polarization curves of the steady-state models are validated by experimental data in the literatures. Numerical results reveal that current density, gas mass fractions, and temperature suddenly change with the sudden change of operating voltage in the mode switching process. The response time of temperature is longer than that of current density and gas mass fractions. In both FC and EC modes, the cell temperature and gradient of gas mass fraction in the oxygen side are larger than that in the hydrogen side. The temperature difference of the entire cell is less than 1.5 K. The highest temperature appears at oxygen-side catalyst layer under the FC mode and at membrane under a more stable EC mode. The cell is exothermic all the time. These dynamic responses and phenomena have important implications for heat analysis and provide proven guidelines for the improvement of URFCs mode switching.

  13. Continuous-wave and Q-switched operation of a resonantly pumped Ho³⁺:KY₃F₁₀ laser.

    Science.gov (United States)

    Schellhorn, Martin; Parisi, Daniela; Eichhorn, Marc; Tonelli, Mauro

    2014-03-01

    We report continuous-wave and repetitively Q-switched operation of a resonantly pumped Ho3+:KY3F10 laser at room temperature. End pumped by a Tm3+-doped silica fiber laser operating at 1938 nm, a maximum laser power of 7.8 W was obtained at a wavelength of ∼2041  nm for 21 W of absorbed pump power, corresponding to a slope efficiency of 60.7% with respect to absorbed power. At a repetition rate of 10 kHz up to 0.78 mJ, energy per pulse was demonstrated with pulse widths of 100 ns. The beam propagation factor (M2) was measured to be <1.26 at the maximum output power.

  14. Investigating the relationship between intra-operative electrolyte abnormalities (sodium and potassium with post-operative complications of coronary artery bypass surgery

    Directory of Open Access Journals (Sweden)

    Kaivan Bagheri

    2013-01-01

    Full Text Available Background: Generally, the electrolyte abnormalities are seen in many hospitalized patients, and this problem increases in ones with heart diseases. The purpose of this study is determination of the prevalence of electrolyte abnormalities during the coronary artery bypass surgery (CABG and detecting the relationship between these abnormalities with the complications after the surgeries. Materials and Methods: This is a cross-sectional study, which is done in Chamran hospital, the medical and educational center of Isfahan, Iran, in 2011. The target population included the patients who have undergone CABG in this hospital. In this study, 100 patients who had been candidates for CABG were selected, and we extracted their recorded intra-operative electrolyte information. The collected data was entered into the computer and analyzed by SPSS software. The Chi-square and t student tests were used for data analysis. Results: The mean ± SD of sodium during CABG was 137.95 ± 4.6 (range 127-152 mg\\dl. Also, the mean ± SD of potassium was 4.65 ± 0.9 (range: 2.9-7.4. According to these results, 48 patients (48% of all had electrolyte imbalance and 52 patients (52% of all were normal. Sodium level in 71% of patients was normal, and in 29% of them was abnormal. Potassium level in 73% of individuals was normal, and in 27% of them was abnormal. Conclusion: Giving an attention to electrolyte abnormalities in patients who have undergone CABG surgery is a considerable necessity for them, and sufficient arrangements are needed to prevent such abnormalities.

  15. THE VALUE OF 99mTc-MIBI MYOCARDIAL PERFUSION SPECT IMAGING IN DETECTING CORONARY ARTERY DISEASE IN PATIENTS WITH VALVULAR DISEASE BEFORE OPERATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective. The aim of this study was to detect coronary artery disease using99m Tc-MIBI myocardial perfusion imaging in patients with valvular disease.Methods. Thirty patients with valvular disease confirmed by echocardiography underwent 99mTc-MIBI myocardial perfusion imaging using multiSPECT 1h after stress test (exercise, dipyridamole or dobutamine test) and were performed coronary angiography within 1 month before valvular operation.Results.For 29 out of the 30 patients, the results of 99mTc-MIBI myocardial perfusion imaging were similar with those of coronary angiography, the concordance rate was 96.7% and the negative predictability was 100%.Conclusion.99m Tc-MIBI myocardial perfusion imaging is a reliable non-invasive method for detecting coronary artery disease in patients with valvular disease and so as to draw up suitable operation programs for them.

  16. Switch wear leveling

    Science.gov (United States)

    Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron

    2015-09-01

    An apparatus for switch wear leveling includes a switching module that controls switching for two or more pairs of switches in a switching power converter. The switching module controls switches based on a duty cycle control technique and closes and opens each switch in a switching sequence. The pairs of switches connect to a positive and negative terminal of a DC voltage source. For a first switching sequence a first switch of a pair of switches has a higher switching power loss than a second switch of the pair of switches. The apparatus includes a switch rotation module that changes the switching sequence of the two or more pairs of switches from the first switching sequence to a second switching sequence. The second switch of a pair of switches has a higher switching power loss than the first switch of the pair of switches during the second switching sequence.

  17. Exciter switch

    Science.gov (United States)

    Mcpeak, W. L.

    1975-01-01

    A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

  18. Pre-operative renal artery embolization and suprarenal IVC filter placement for prevention of fat embolization in renal angiomyolipoma with venous extension.

    Science.gov (United States)

    Cornman-Homonoff, Joshua; Li, David; Schiffman, Marc

    2017-01-26

    Though generally considered benign, angiomyolipomas can invade through the renal vein into the inferior vena cava, putting patients at risk of catastrophic pulmonary fat embolization. Venous invasion is thus an indication for surgical resection but is thought to increase the risk of adverse operative outcomes including intraoperative hemorrhage and embolization of fat and/or tumor thrombus. We report a novel approach to mitigating these complications illustrated in the case of a 43-year-old woman with IVC-invasive renal AML who underwent successful radical nephrectomy after concurrent pre-operative renal artery embolization and placement of a retrievable suprarenal IVC filter.

  19. Optical packet switching

    Science.gov (United States)

    Shekel, Eyal; Ruschin, Shlomo; Majer, Daniel; Levy, Jeff; Matmon, Guy; Koenigsberg, Lisa; Vecht, Jacob; Geron, Amir; Harlavan, Rotem; Shfaram, Harel; Arbel, Arnon; McDermott, Tom; Brewer, Tony

    2005-02-01

    We report here a scalable, multichassis, 6.3 terabit core router, which utilizes our proprietary optical switch. The router is commercially available and deployed in several customer sites. Our solution combines optical switching with electronic routing. An internal optical packet switching network interconnects the router"s electronic line cards, where routing and buffering functions take place electronically. The system architecture and performance will be described. The optical switch is based on Optical Phased Array (OPA) technology. It is a 64 x 64, fully non-blocking, optical crossbar switch, capable of switching in a fraction of a nanosecond. The basic principles of operation will be explained. Loss and crosstalk results will be presented, as well as the results of BER measurements of a 160 Gbps transmission through one channel. Basic principles of operation and measured results will be presented for the burst-mode-receivers, arbitration algorithm and synchronization. Finally, we will present some of our current research work on a next-generation optical switch. The technological issues we have solved in our internal optical packet network can have broad applicability to any global optical packet network.

  20. Dual-mode operation of a twisted nematic liquid crystal cell by switching between dynamic and memory modes.

    Science.gov (United States)

    Song, Dong Han; Kim, Ki-Han; Kim, Jung-Wook; Kim, Jae Chang; Yoon, Tae-Hoon

    2011-06-01

    We propose a twisted nematic liquid crystal device that can be operated in dynamic or memory mode, based on the information content to be displayed at that time. +90°-twisted and -90°-twisted states are used as two stable states for operation in the memory mode. A vertical electric field is applied to realize gray levels for operation in the dynamic mode. The proposed device has a memory retention time of over a month for the memory mode and a response time of 12 ms for the dynamic mode. Contrast ratios of over 500∶1 can be obtained in both the dynamic and memory modes.

  1. Practical switching power supply design

    CERN Document Server

    Brown, Martin C

    1990-01-01

    Take the ""black magic"" out of switching power supplies with Practical Switching Power Supply Design! This is a comprehensive ""hands-on"" guide to the theory behind, and design of, PWM and resonant switching supplies. You'll find information on switching supply operation and selecting an appropriate topology for your application. There's extensive coverage of buck, boost, flyback, push-pull, half bridge, and full bridge regulator circuits. Special attention is given to semiconductors used in switching supplies. RFI/EMI reduction, grounding, testing, and safety standards are also deta

  2. Scaling and passively Q-switch operation of a Nd:YAG laser pumped laterally through a YAG prism

    Science.gov (United States)

    Dascalu, T.; Salamu, G.; Sandu, O.; Dinca, M.; Pavel, N.

    2015-04-01

    We report on scaling of a laser configuration in which a YAG prism is used to couple the pump beam from a fiber-coupled diode laser directly into a Nd:YAG medium. Several resonator geometries have been investigated. In free generation regime laser pulses at 1.06 μm with energy of 22.1 mJ for the pump energy of 44.6 mJ were obtained from a 10.0 mm long, 1.0-at% Nd:YAG single crystal that had the high-reflectivity mirror coated directly on one of the laser crystal surface. The slope efficiency was 0.51. A similar uncoated Nd:YAG crystal placed in a plane-plane resonator delivered laser pulses with 17.8 mJ energy under the pump with 45.4 mJ energy, at 0.40 slope efficiency. Further, a passively Q-switched Nd:YAG/Cr4+:YAG composite ceramic laser pumped through a YAG prism has been built. Using a Cr4+:YAG saturable absorber of 0.85 initial transmission the device delivered laser pulses with 0.29 mJ energy and 11 ns duration. The output performances are compared to those obtained in a classical end-pumping scheme.

  3. Operating characteristics of superconducting fault current limiter using 24kV vacuum interrupter driven by electromagnetic repulsion switch

    Energy Technology Data Exchange (ETDEWEB)

    Endo, M; Hori, T; Koyama, K; Kaiho, K; Yanabu, S [Tokyo Denki University, 2-2 Kandanishiki-chou Chiyoda-ku Tokyo 101-8457 (Japan); Yamaguchi, I; Arai, K [National Institute of Advanced Industrial Science and Technology(AIST), 1-1-1 Umezono, Tsukuba-shi, Ibaraki 305-8565 (Japan)], E-mail: yanabu@e.dendai.ac.jp

    2008-02-01

    Using a high temperature superconductor, we constructed and tested a model Superconducting Fault Current Limiter (SFCL). SFCL which has a vacuum interrupter with electromagnetic repulsion mechanism. We set out to construct high voltage class SFCL. We produced the electromagnetic repulsion switch equipped with a 24kV vacuum interrupter(VI). There are problems that opening speed becomes late. Because the larger vacuum interrupter the heavier weight of its contact. For this reason, the current which flows in a superconductor may be unable to be interrupted within a half cycles of current. In order to solve this problem, it is necessary to change the design of the coil connected in parallel and to strengthen the electromagnetic repulsion force at the time of opening the vacuum interrupter. Then, the design of the coil was changed, and in order to examine whether the problem is solvable, the current limiting test was conducted. We examined current limiting test using 4 series and 2 parallel-connected YBCO thin films. We used 12-centimeter-long YBCO thin film. The parallel resistance (0.1{omega}) is connected with each YBCO thin film. As a result, we succeed in interrupting the current of superconductor within a half cycle of it. Furthermore, series and parallel-connected YBCO thin film could limit without failure.

  4. Neurological Study of Radial Nerve Conduction During Endoscopic Radial Artery Harvesting:An Intra‐Operative Evaluation

    Directory of Open Access Journals (Sweden)

    Gianluigi Bisleri

    2014-08-01

    Full Text Available Endoscopic radial artery harvesting (ERAH is a feasible and attractive minimally invasive approach for conduit procurement, however there have been concerns about a potential neurological damage occurring at the harvest limb site secondary to injury of the radial nerve during endoscopic harvesting. We present a case of ERAH in which we evaluated intraoperatively the characteristics of radial nerve conduction by means of electroneuromyography (ENM during harvesting. No pathological changes of nerve conduction were detected at the harvest limb site during surgery and postoperatively, thereby supporting the benefits of the endoscopic approach in terms of neurological outcomes following radial artery procurements with a less invasive approach.

  5. Low arterial pressure on admission as a predictor of mortality in operated patients with type A aortic dissection

    Directory of Open Access Journals (Sweden)

    Pavlović Katica

    2011-01-01

    Full Text Available Background/Aim. Hypertension is a known predictor of proximal aortic dissection, but it is not commonly present in these patients on presentation. The associations between ascending aorta with left ventricular hypertrophy, cardiovascular risk factors and coronary atherosclerosis, and outcome of these patients are not fully elucidated. Methods. This retrospective study included 55 consecutive patients with acute type A aortic dissection treated surgically in our institution during the last 2 years. The diagnosis was based on imaging studies. Diameter of ascending aorta was measured with echocardiography. Results. The mean age of the patients was 55.4 ± 12.19 years, and 72.7% were men. A history of arterial hypertension was present in 76.4% of the patients. Maximal ascending aorta diameter was 4.09 ± 0.59 cm, while patients with frank aneurysm accounted for 5.5%. Systolic blood pressure on admission was < 150 mmHg in 58.2% of the patients. Diastolic blood pressure on admission was < 90 mmHg in 54.5% of the patients. Mean arterial pressure on admission was 104.9 ± 24.6 mmHg. No correlations were demonstrated between maximal ascending aorta diameter and diameter of the left ventricular wall, any obtained risk factor and with coronary artery atherosclerosis (p > 0.05. After six months 11 (20% patients died, while intrahospital mortality was 72%. According to logistic regression analysis which included traditional risk factors, echo parameters, coronary artery disease and logistic euro scor, mean arterial blood pressure was the independent predictor of a six-month mortality [RR 0.956; CI (0.918-0.994 ; p = 0.024]. Conclusion. In our population the acute type A aortic dissection occurred rarely in the setting of frank ascending aortic aneurysms > 5.0 cm. The majority of patients had a history of arterial hypertension. A history of arterial hypertension was not associated with maximal ascending aorta diameter. Mean arterial blood pressure was the

  6. Thermodynamics of the GTP-GDP-operated conformational switch of selenocysteine-specific translation factor SelB.

    Science.gov (United States)

    Paleskava, Alena; Konevega, Andrey L; Rodnina, Marina V

    2012-08-10

    SelB is a specialized translation factor that binds GTP and GDP and delivers selenocysteyl-tRNA (Sec-tRNA(Sec)) to the ribosome. By analogy to elongation factor Tu (EF-Tu), SelB is expected to control the delivery and release of Sec-tRNA(Sec) to the ribosome by the structural switch between GTP- and GDP-bound conformations. However, crystal structures of SelB suggested a similar domain arrangement in the apo form and GDP- and GTP-bound forms of the factor, raising the question of how SelB can fulfill its delivery function. Here, we studied the thermodynamics of guanine nucleotide binding to SelB by isothermal titration calorimetry in the temperature range between 10 and 25 °C using GTP, GDP, and two nonhydrolyzable GTP analogs, guanosine 5'-O-(γ-thio)triphosphate (GTPγS) and guanosine 5'-(β,γ-imido)-triphosphate (GDPNP). The binding of SelB to either guanine nucleotide is characterized by a large heat capacity change (-621, -467, -235, and -275 cal × mol(-1) × K(-1), with GTP, GTPγS, GDPNP, and GDP, respectively), associated with compensatory changes in binding entropy and enthalpy. Changes in heat capacity indicate a large decrease of the solvent-accessible surface area in SelB, amounting to 43 or 32 amino acids buried upon binding of GTP or GTPγS, respectively, and 15-19 amino acids upon binding GDP or GDPNP. The similarity of the GTP and GDP forms in the crystal structures can be attributed to the use of GDPNP, which appears to induce a structure of SelB that is more similar to the GDP than to the GTP-bound form.

  7. Charging of capacitors with double switch. The principle of operation of auto-zero and chopper-stabilized DC amplifiers

    CERN Document Server

    Yordanov, Vasil G; Manolev, Stojan G; Mishonov, Todor M

    2015-01-01

    The principle of operation of auto-zero and chopper-stabilized DC amplifiers, which is realized in many contemporary operational amplifiers is illustrated by a simple experimental setup given at the Open Experimental Physics Olympiad 2014 - "The Day of the Capacitor", held in Sofia and Gevgelija. The Olympiad was organized by the Sofia Branch of the Union of Physicists in Bulgaria and the Regional Society of Physicists of Strumica, Macedonia. In addition to the solution of the secondary school task in the paper is given a detailed engineering description of the patent by Edwin Goldberg and Jules Lehmann, Stabilized direct current amplifier, U.S. Patent 2,684,999 (1949).

  8. Early detection and treatment of myocardial ischaemia after operation using continual ambulatory arterial pressure monitoring and ECG ST segment analysis.

    Science.gov (United States)

    Edwards, N D; Troy, G; Yeo, W; Jackson, P; Reilly, C S

    1995-10-01

    We report a case in which the use of continual ambulatory arterial pressure monitoring and ECG ST-segment analysis allowed early detection and treatment of myocardial ischaemia in the postoperative period. We believe that this case illustrates the potential value of ambulatory monitoring in the early postoperative period in high-risk patients.

  9. Platform switching and bone platform switching.

    Science.gov (United States)

    Carinci, Francesco; Brunelli, Giorgio; Danza, Matteo

    2009-01-01

    Bone platform switching involves an inward bone ring in the coronal part of the implant that is in continuity with the alveolar bone crest. Bone platform switching is obtained by using a dental fixture with a reverse conical neck. A retrospective study was performed to evaluate the effectiveness of conventional vs reverse conical neck implants. In the period between May 2004 and November 2007, 86 patients (55 females and 31 males; median age, 53 years) were operated and 234 implants were inserted: 40 and 194 were conventional vs reverse conical neck implants, respectively. Kaplan-Meier algorithm and Cox regression were used to detect those variables associated with the clinical outcome. No differences in survival and success rates were detected between conventional vs reverse conical neck implants alone or in combination with any of the studied variables. Although bone platform switching leads to several advantages, no statistical difference in alveolar crest resorption is detected in comparison with reverse conical neck implants. We suppose that the proximity of the implant abutment junction to the alveolar crestal bone gives no protection against the microflora contained in the micrograph. Additional studies on larger series and a combination of platform switching and bone platform switching could lead to improved clinical outcomes.

  10. Atomic Scale Plasmonic Switch.

    Science.gov (United States)

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2016-01-13

    The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.

  11. 接地开关电动操动机构的研发与结构设计研究%Grounding Switch Electric Operating Mechanism Research and Structure Design Research

    Institute of Scientific and Technical Information of China (English)

    李小平

    2014-01-01

    With the development of the electric power industry, the high voltage switch equipment also got great development. Parts of the high voltage switch disconnected or grounding switch in the closing switch points, used for gear transmission structure or screw the two transmission ways. The two transmission ways to switch design put forward higher request, only the design more perfect switch electric operating mechanism, to provide support for the drive way. In addition, the modern distribution system and power system is becoming more and more high to the requirement of switchgear, so, must accelerate the earthing switch electric operation, promote the earthing switch in many aspects, such as monitoring, control and protection of intelligent, improve the accuracy of the grounding switch electric operating mechanism and reliability.%随着电力事业的发展,高压开关设备也得到了很大的发展。高压开关中的部分隔离开关或接地开关在进行开关分合闸时,使用了传动结构为齿轮或丝杆的两种传动方式。这两种传动方式对开关设计提出了更高的要求,只有设计出更完善的开关电动操动机构,才能为这种传动方式提供支撑。此外,现代配电系统和用电系统对开关设备的要求也越来越高,所以,必须要加速接地开关的电动操作,促进接地开关在监测、控制和保护等诸多方面的智能化,提高接地开关电动操作机构的准确性和可靠程度。

  12. A High-Performance Operational Amplifier for High-Speed High-Accuracy Switch-Capacitor Cells

    Institute of Scientific and Technical Information of China (English)

    Qi Fan; Ning Ning; Qi Yu; Da Chen

    2007-01-01

    A highspeed highaccuracy fully differenttial operational amplifier (opamp) is realized based on noMillercapacitor feedforward (NMCF) compensation scheme. In order to achieve a good phase margin, the NMCF compensation scheme uses the positive phase shift of lefthalfplane (LHP) zero caused by the feedforward path to counteract the negative phase shift of the nondominant pole. Compared to traditional Miller compensation method, the opamp obtains high gain and wide band synchronously without the polesplitting effect while saves significant chip area due to the absence of the Miller capacitor. Simulated by the 0.35 μm CMOS RF technology, the result shows that the openloop gain of the opamp is 118 dB with the unity gainbandwidth (UGBW)of 1 GHz, and the phase margin is 61°while the settling time is 5.8 ns when achieving 0.01% accuracy. The opamp is especially suitable for the frontend sample/hold (S/H)cell and the multiplying D/A converter(MDAC) module of the highspeed highresolution pipelined A/D converters(ADCs).

  13. Numerical Study of Cerebroarterial Hemodynamic Changes Following Carotid Artery Operation: A Comparison Between Multiscale Modeling and Stand-Alone Three-Dimensional Modeling.

    Science.gov (United States)

    Liang, Fuyou; Oshima, Marie; Huang, Huaxiong; Liu, Hao; Takagi, Shu

    2015-10-01

    Free outflow boundary conditions have been widely adopted in hemodynamic model studies, they, however, intrinsically lack the ability to account for the regulatory mechanisms of systemic hemodynamics and hence carry a risk of producing incorrect results when applied to vascular segments with multiple outlets. In the present study, we developed a multiscale model capable of incorporating global cardiovascular properties into the simulation of blood flows in local vascular segments. The multiscale model was constructed by coupling a three-dimensional (3D) model of local arterial segments with a zero-one-dimensional (0-1-D) model of the cardiovascular system. Numerical validation based on an idealized model demonstrated the ability of the multiscale model to preserve reasonable pressure/flow wave transmission among different models. The multiscale model was further calibrated with clinical data to simulate cerebroarterial hemodynamics in a patient undergoing carotid artery operation. The results showed pronounced hemodynamic changes in the cerebral circulation following the operation. Additional numerical experiments revealed that a stand-alone 3D model with free outflow conditions failed to reproduce the results obtained by the multiscale model. These results demonstrated the potential advantage of multiscale modeling over single-scale modeling in patient-specific hemodynamic studies. Due to the fact that the present study was limited to a single patient, studies on more patients would be required to further confirm the findings.

  14. Seidel Switching and Graph Energy

    NARCIS (Netherlands)

    Haemers, W.H.

    2012-01-01

    Abstract: The energy of a graph Γ is the sum of the absolute values of the eigenvalues of the adjacency matrix of Γ. Seidel switching is an operation on the edge set of Γ. In some special cases Seidel switching does not change the spectrum, and therefore the energy. Here we investigate when Seidel s

  15. Arterial waveform analysis.

    Science.gov (United States)

    Esper, Stephen A; Pinsky, Michael R

    2014-12-01

    The bedside measurement of continuous arterial pressure values from waveform analysis has been routinely available via indwelling arterial catheterization for >50 years. Invasive blood pressure monitoring has been utilized in critically ill patients, in both the operating room and critical care units, to facilitate rapid diagnoses of cardiovascular insufficiency and monitor response to treatments aimed at correcting abnormalities before the consequences of either hypo- or hypertension are seen. Minimally invasive techniques to estimate cardiac output (CO) have gained increased appeal. This has led to the increased interest in arterial waveform analysis to provide this important information, as it is measured continuously in many operating rooms and intensive care units. Arterial waveform analysis also allows for the calculation of many so-called derived parameters intrinsically created by this pulse pressure profile. These include estimates of left ventricular stroke volume (SV), CO, vascular resistance, and during positive-pressure breathing, SV variation, and pulse pressure variation. This article focuses on the principles of arterial waveform analysis and their determinants, components of the arterial system, and arterial pulse contour. It will also address the advantage of measuring real-time CO by the arterial waveform and the benefits to measuring SV variation. Arterial waveform analysis has gained a large interest in the overall assessment and management of the critically ill and those at a risk of hemodynamic deterioration.

  16. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1999-01-01

    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...... by employing a feedback loop. The gate oxide will not be subject to voltages exceeding the supply voltage difference.Realistic switches have been simulated with HSPICE. The simulations show that the switch circuits operate very well, even when the supply voltage approaches the technology's threshold voltage....

  17. Demonstration of reconfigurable joint orbital angular momentum mode and space switching

    OpenAIRE

    Jun Liu; Jian Wang

    2016-01-01

    We propose and demonstrate space-selective switch functions employing orbital angular momentum (OAM) modes in the space domain for switching network. One is the switching among different OAM modes having different spatial phase structures, called OAM mode switching. The other is the switching among different space locations, called space switching. The switching operation mechanism relies on linear optics. Reconfigurable 4 × 4 OAM mode switching, space switching, and joint OAM mode and space ...

  18. Nucleosome switches.

    Science.gov (United States)

    Schwab, David J; Bruinsma, Robijn F; Rudnick, Joseph; Widom, Jonathan

    2008-06-06

    We present a statistical-mechanical model for the positioning of nucleosomes along genomic DNA molecules as a function of the strength of the binding potential and the chemical potential of the nucleosomes. We show that a significant section of the DNA is composed of two-level nucleosome switching regions where the nucleosome distribution undergoes a localized, first-order transition. The location of the nucleosome switches shows a strong correlation with the location of gene-regulation regions.

  19. The Role of MOR and the CI Operator Sites on the Genetic Switch of the Temperate Bacteriophage TP901-1

    DEFF Research Database (Denmark)

    Pedersen, Margit; Hammer, Karin

    2008-01-01

    A genetic switch controls whether the temperate bacteriophage TP901-1 will enter a lytic or a lysogenic life cycle after infection of its host, Lactococcus lactis. We studied this bistable switch encoded in a small DNA fragment of 979 bp by fusing it to a reporter gene on a low-copy-number plasmid...

  20. Performance analysis of a low-complexity and efficient QoS differentiation algorithm for bufferless optical packet switches with shared wavelength converters in asynchronous operation

    DEFF Research Database (Denmark)

    Nord, Martin

    2004-01-01

    This paper presents a simulation study of a low-complexity optical packet switching quality of service differentiation scheme, aiming at minimising the penalty of offering packet loss rate isolation in an optical packet switch with a wavelength converter pool. Special emphasis is given to potential...

  1. A review of opening switch technology for inductive energy storage

    Science.gov (United States)

    Schoenbach, K. H.; Kristiansen, M.; Schaefer, G.

    1984-08-01

    A review of the state of the art in opening switches is presented. The general operating principles and present and potential future operating parameters for several switch categories are discussed. Among the switch categories described are: mechanical, solid state, vacuum arc, crossed field, fuse, explosive, plasma gun, superconducting, thermal, MHD instability, diffuse discharge, plasma erosion switches, and reflex triodes.

  2. Passively Q-switched thulium-doped fiber laser with silver-nanoparticle film as the saturable absorber for operation at 2.0 µm

    Science.gov (United States)

    Ahmad, H.; Samion, M. Z.; Muhamad, A.; Sharbirin, A. S.; Ismail, M. F.

    2016-12-01

    In this work, a compact thulium-doped fiber laser with a Q-switched output is proposed and demonstrated. A thulium-doped fiber is used for the laser, with a peak absorption of 200 dB m-1 at 790 nm and a cutoff wavelength of 1350 nm as the primary gain medium, and a silver-based saturable absorber as the pulse generation mechanism. The pulses obtained from the proposed laser have repetition rates from 38.3 kHz up to 56.2 kHz, with a pulse width as low as 4.2 µs and pulse energy as high as 67.3 nJ at a maximum pump power of 228.8 mW. The generated pulses are highly stable, showing no changes or fluctuations over operation for a period of 60 min, and further validated with signal-to-noise ratios of 57.0 dB and 59.5 dB in the optical and frequency domains respectively. The proposed laser has high potential for eye-safe applications in manufacturing and medicine.

  3. Mechanism of single atom switch on silicon

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Thirstrup, C.

    1998-01-01

    We demonstrate single atom switch on silicon which operates by displacement of a hydrogen atom on the silicon (100) surface at room temperature. We find two principal effects by which the switch is controlled: a pronounced maximum of the switching probability as function of sample bias...

  4. Lung volumes, ventricular function and pulmonary arterial flow in children operated on for left-sided congenital diaphragmatic hernia: long-term results

    Energy Technology Data Exchange (ETDEWEB)

    Abolmaali, Nasreddin; Koch, Arne [Dresden University of Technology, OncoRay - Molecular and Biological Imaging, Medical Faculty Carl Gustav Carus, Dresden (Germany); Goetzelt, Knut; Vogelberg, Christian [University Clinics Carl Gustav Carus, Dresden University of Technology, Clinic and Policlinic for Pediatrics - Pediatric Pulmonology, Dresden (Germany); Hahn, Gabriele [University Clinics Carl Gustav Carus, Dresden University of Technology, Institute and Policlinic for Radiology - Pediatric Radiology, Dresden (Germany); Fitze, Guido [University Clinics Carl Gustav Carus, Dresden University of Technology, Clinic and Policlinic for Pediatric Surgery, Dresden (Germany)

    2010-07-15

    To compare MRI-based functional pulmonary and cardiac measurements in the long-term follow-up of children operated on for left-sided congenital diaphragmatic hernia (CDH) with age- and body size-matched healthy controls. Twelve children who received immediate postnatal surgery for closure of isolated left-sided CDH were included and received basic medical examinations, pulmonary function testing and echocardiography. MRI included measurement of lung volume, ventricular function assessment and velocity-encoded imaging of the pulmonary arteries and was compared with the data for 12 healthy children matched for age and body size. While patients' clinical test results were not suspicious, comparison between the MRI data for patients and those for healthy controls revealed significant differences. In patients, the volumes of the left lungs were increased and the tidal volume was larger on the right side. While the stroke volumes of both ventricles were reduced, heart rate and ejection fraction were increased. Flow, acceleration time and cross-sectional area of the left pulmonary artery were reduced. Functional MRI detected pulmonary and cardiac findings in the late follow-up of CDH children which may be missed by standard clinical methods and might be relevant for decisions regarding late outcome and treatment. (orig.)

  5. Ginsenoside Rb1 Attenuates Agonist-Induced Contractile Response via Inhibition of Store-Operated Calcium Entry in Pulmonary Arteries of Normal and Pulmonary Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Rui-Xing Wang

    2015-03-01

    Full Text Available Background: Pulmonary hypertension (PH is characterized by sustained vasoconstriction, enhanced vasoreactivity and vascular remodeling, which leads to right heart failure and death. Despite several treatments are available, many forms of PH are still incurable. Ginsenoside Rb1, a principle active ingredient of Panax ginseng, exhibits multiple pharmacological effects on cardiovascular system, and suppresses monocrotaline (MCT-induced right heart hypertrophy. However, its effect on the pulmonary vascular functions related to PH is unknown. Methods: We examined the vasorelaxing effects of ginsenoside Rb1 on endothelin-1 (ET-1 induced contraction of pulmonary arteries (PAs and store-operated Ca2+ entry (SOCE in pulmonary arterial smooth muscle cells (PASMCs from chronic hypoxia (CH and MCT-induced PH. Results: Ginsenoside Rb1 elicited concentration-dependent relaxation of ET-1-induced PA contraction. The vasorelaxing effect was unaffected by nifedipine, but abolished by the SOCE blocker Gd3+. Ginsenoside Rb1 suppressed cyclopiazonic acid (CPA-induced PA contraction, and CPA-activated cation entry and Ca2+ transient in PASMCs. ET-1 and CPA-induced contraction, and CPA-activated cation entry and Ca2+ transients were enhanced in PA and PASMCs of CH and MCT-treated rats; the enhanced responses were abolished by ginsenoside Rb1. Conclusion: Ginsenoside Rb1 attenuates ET-1-induced contractile response via inhibition of SOCE, and it can effectively antagonize the enhanced pulmonary vasoreactivity in PH.

  6. The Application of High Temperature Superconducting Materials to Power Switches

    CERN Document Server

    March, S A; Ballarino, A

    2009-01-01

    Superconducting switches may find application in superconducting magnet systems that require energy extraction. Such superconducting switches could be bypass-switches that are operated in conjunction with a parallel resistor or dump-switches where all of the energy is dissipated in the switch itself. Bypass-switches are more suited to higher energy circuits as a portion of the energy can be dissipated in the external dump resistor. Dump- switches require less material and triggering energy as a lower switch resistance is needed to achieve the required total dump resistance. Both superconducting bypass-switches and superconducting dump-switches can be ther- mally activated. Switching times that are comparable to those obtained with mechanical bypass-switch systems can be achieved using a co-wound heater that is powered by a ca- pacitor discharge. Switches that have fast thermal diffusion times through the insulation can be modelled as a lumped system whereas those with slow thermal diffusion times were modelle...

  7. [Combined arterial bypass operation and coumarin therapy--a concept for long-term management and its conditions].

    Science.gov (United States)

    Kühnel, L; Heinrichs, C; Wache, I; Neugebauer, J

    1991-01-01

    Antithrombotics of cumarin type or with antiplatelet effect are preferred to obtain results from vascular surgical interventions in arterial occlusion disease. In our experience the combination with cumarin long term therapy seems to be the better method, especially if the following conditions can be achieved: very good compliance of patients respectively strict consideration of absolute and relative contraindications, a sufficient number of patients who are treated and a long enough experience of therapeutists followed by using the recommendations of the WHO expert committee for the worldwide application of standardization in measuring the anticoagulation effect, using reagents and calibration materials, and the expression of results in INR. Further in our anticoagulation behaviour we are used influencing risk factors, having a good cooperation between patients and doctors during secondary diseases and new drug intake. For dental surgery we prefer a Quick test between 30 and 35% activity or 1, 9 and 2, 1 INR. With Phenprocoumon (Falithrom, Markumar) we use the long term anticoagulation effect without several daily applications. Since September 1987 there has been the possibility of a computer assisted programme for dose prediction.

  8. Alternate switching between microbial fuel cell and microbial electrolysis cell operation as a new method to control H2O2 level in Bioelectro-Fenton system

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Wang, Yong; Angelidaki, Irini

    2015-01-01

    by switching the system to MFC mode of operation. Complete decolorization and mineralization of 50 mg L−1 methylene blue (MB) was achieved in the MEC mode with apparent first order rate constants of 0.43 and 0.22 h−1, respectively. After switching to the MFC mode, residual H2O2 of 180 mg L−1 was removed...... at a removal rate of 4.61 mg L−1 h−1 while generating a maximum current density of 0.49 A m−2. The MB degradation and residual H2O2 removal were affected by external resistance, cathode pH and initial MB concentration. Furthermore, the system performance was enhanced under stack operation. This study provides...

  9. Medical operating personnel exposition levels during intracoronary irradiation using a Re188 full filled balloon catheter after percutaneous transluminal coronary artery

    Energy Technology Data Exchange (ETDEWEB)

    Ponce V, F.; Peix G, A.; Llerena R, L.; Santana V, L. [Instituto de Cardiologia, La Habana (Cuba); Lopez D, A. [Hospital Hermanos Amejeiras, La Habana (Cuba)

    2006-07-01

    The intracoronary irradiation using a full filled conventional balloon catheter with Rhenium 188 (Re188) after Percutaneous Transluminal Coronary Artery (PTCA) is a new relative treatment technique to reduce restenosis where the medical operating personnel are exposed to additional radiation ionizing level in the cath lab. In this study a radiation exposure level to medical operating personnel in the cath lab were measured with a Geiger Muller detector in 7 place to different distance from patient (to chest and abdominal region) catheter tabletop during a randomized clinical trial carried out in 25 patients whose were treated. The average concentrated Re188 activity used and treatment time were 5256{+-}2371 MBq/ml in 1.5-2 ml and 466{+-}195 seconds. At 3 cm from right arm patient the average maximum exposition rate were 0,63 mSv/h and 0,51 mSv h, to chest and abdominal patient level, respectively, where also average exposed dose per treated patient was 0,06 mSv and 0,05 mSv, respectively. Our results show that intracoronary irradiation with Re188 in the cath lab do not increase significatively the exposure radiation level to medical operating staff during treatment procedure and it is safe according national and international radiation protection regulations. (Author)

  10. A Novel Diagnostic Technique for Open-switch Faults of Inverters Based on Operating Mode Analysis%基于运行模式分析的逆变器功率管开路故障诊断方法

    Institute of Scientific and Technical Information of China (English)

    姜保军; 安群涛

    2012-01-01

    A novel real-time diagnostic and locating technique for open-switch faults in inverters was proposed in this paper. Based on the switching function model and operating modes of the inverter, the method is implemented with simple hardware circuits according to different voltages of the lower switches between faulty and normal conditions, which has advantages of low cost, high reliability, short diagnostic time and good applicability. The operating modes of inverters were researched and the real voltages of the lower switches under both normal condition and the upper and lower switches open-circuit faults were analyzed. The analytic results indicate that different error voltages are derived by the upper and lower switches open-circuit faults respectively, comparing with the estimated voltages of lower switches deduced from the switching function model. Otherwise, error voltages can be developed by switching delay, dead time and measurement noise, which need to be eliminated. Threshold compares and pulse-width limits are used to filter the error voltages coming with switching delay and measurement noise. In addition, in order to eliminate the error voltages during the dead time, the error voltages are modulated with corresponding switching signals. This paper presented a realization scheme using hardware circuits, and simulations and experiments were completed in field-oriented control system of permanent magnet synchronous motor. The results validate the proposed method and indicate that the method is immune to closed loop control strategies. Fault detection can be achieved within 10 μm.%提出一种新型逆变器功率管开路故障的在线诊断与定位方法.该方法在逆变器开关函数模型和运行模式分析的基础上,根据故障和正常状态下桥臂下管承受电压的不同,采用简单的硬件电路来实现,具有成本低、可靠性高、诊断时间短、适用性强等优点.对逆变器的运行模式进行研究,分别对正常状

  11. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-04-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  12. Comparison of the effectiveness of oral sildenafil versus oxygen administration as a test for feasibility of operation for patients with secondary pulmonary arterial hypertension.

    Science.gov (United States)

    Ajami, Gholam Hossein; Borzoee, Mohammad; Radvar, Mohammad; Amoozgar, Hamid

    2008-05-01

    It is shown that phosphodiesterase type 5 (PDE5) inhibitors such as sildenafil can modulate pulmonary arterial hypertension (PAH) via increasing the level of guanosine-3,5-cyclic monophosphate (cGMP) and decreases pulmonary artery pressure (PAP). In this study we determined the effectiveness of sildenafil and compared its efficacy with inhaled nasal oxygen (O2) during cardiac catheterization in patients with congenital heart diseases (CHD) and PAH, as a test of feasibility for surgical repair of the patients. We studied 15 patients, 9 male and 6 female, with a mean age of 8.3 years. Hemodynamic measurements were made at baseline, after O2 administration for 20 min (5 L/min by mask), and then 45 min after administration of a single dose of sildenafil (0.5 mg/kg orally or via nasogastric tube). Mean PAP at baseline was 72.2 +/- 12.54 mm Hg and was reduced by sildenafil to 52.5 +/- 9.6 and by O2 to 61.3 +/- 10.39. Both sildenafil and O2 decreased PAP effectively (p = 0.08 and p = 0.04, respectively). Pulmonary vascular resistance (PVR) was calculated for 12 patients, with a baseline level of 9.08 +/- 1.09 mm Hg . L(-1) . min, which was significantly decreased by O2, to 3.74 +/- 0.43, and by sildenafil, to 5.93 +/- 0.75 (p = 0.005 and p = 0.05, respectively). Sildenafil, as a single oral dose, can effectively reduce PAP and PVR. This novel PDE5 inhibitor can be used for assessment of feasibility of operation for patients with CHD and PAH when inhaled NO is not available.

  13. Atherosclerosis Alters Loading-Induced Arterial Damage: Implications for Robotic Surgery.

    Directory of Open Access Journals (Sweden)

    Rachel Geenens

    Full Text Available Lack of intra-operative haptic information during robotic surgery increases the risk for unintended tissue overload and damage. Knowledge about the acute and chronic fundamental relationship between force load and induced damage in healthy and diseased arteries is crucial to enable intra-operative haptic feedback or shared autonomy and improve patient safety.Arteries of wildtype and atherosclerotic mice were clamped in vivo for 2 minutes (0.0N, 0.6N or 1.27N. Histological analysis (Verhoeff's-Van Gieson, Osteopontin, CD45, CD105 was performed immediately, or after 6 hours, 2 weeks or 1 month. Endothelium-dependent and-independent vasodilatation was assessed immediately or 1 month after clamping.Endothelium dependent vasodilatation is worse after clamping of wildtype arteries, but is restored after one month. Clamping also results in flattening of the innermost elastic membrane of both genotypes, which is reversed over time for wildtype arteries but not for vessels from atherosclerotic mice. Higher osteopontin content in wildtype and LDLR-/- mice after 2 weeks suggests a phenotypic switch of the medial smooth muscle cells (SMCs, an effect that is reversed after 1 month. While inflammation in the intima diminishes, medial CD45 content rises through time in both genotypes. CD105 staining shows that even manipulation without clamping results in endothelial cell loss in both LDLR+/+ and LDLR-/- mice.Arterial clamping induces different acute and long-term injury to the vessel wall of atherosclerotic and healthy arteries.

  14. Sector Switching

    DEFF Research Database (Denmark)

    Newman, Carol; Rand, John; Tarp, Finn

    Much of the literature on industry evolution has found firm dynamics to be an important source of sector-level productivity growth. In this paper, we ask whether the delineation of entry and exit firms matters in assessing the impact of firm turnover. Using detailed firm level data from Vietnam......-level determinants of firm exit and switching, which need to be carefully considered in the search for effective policy...

  15. Sector Switching

    DEFF Research Database (Denmark)

    Newman, Carol; Rand, John; Tarp, Finn

    Much of the literature on industry evolution has found firm dynamics to be an important source of sector-level productivity growth. In this paper, we ask whether the delineation of entry and exit firms matters in assessing the impact of firm turnover. Using detailed firm level data from Vietnam, ......-level determinants of firm exit and switching, which need to be carefully considered in the search for effective policy...

  16. Variant origin of right testicular artery – a rare case

    Directory of Open Access Journals (Sweden)

    Salve VM

    2010-02-01

    Full Text Available Testicular arterial anatomy is important for testicular and renal surgeries. It may vary at the origin and arise from renal artery, suprarenal artery or lumbar artery. During routine dissection of 52-year-old male cadaver; the right testicular artery arising from right aberrant renal artery was found. Anatomical variation of testicular arteries is reported to be 4.7%. Presence of aberrant renal artery is seen in 13–16% of cases only. The origin of right testicular artery from right aberrant renal artery is very rare. Thus knowledge of this type of variation is very important in avoiding complications during operative surgeries.

  17. Modeling and control of switching max-plus-linear systems with random and deterministic switching

    NARCIS (Netherlands)

    Van den Boom, T.J.J.; De Schutter, B.

    2012-01-01

    Switching max-plus-linear (SMPL) systems are discrete-event systems that can switch between different modes of operation. In each mode the system is described by a max-plus-linear state equation and a max-plus-linear output equation, with different system matrices for each mode. The switching may de

  18. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)

    2012-01-20

    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  19. Molecular Rotors as Switches

    Directory of Open Access Journals (Sweden)

    Kang L. Wang

    2012-08-01

    Full Text Available The use of a functional molecular unit acting as a state variable provides an attractive alternative for the next generations of nanoscale electronics. It may help overcome the limits of conventional MOSFETd due to their potential scalability, low-cost, low variability, and highly integratable characteristics as well as the capability to exploit bottom-up self-assembly processes. This bottom-up construction and the operation of nanoscale machines/devices, in which the molecular motion can be controlled to perform functions, have been studied for their functionalities. Being triggered by external stimuli such as light, electricity or chemical reagents, these devices have shown various functions including those of diodes, rectifiers, memories, resonant tunnel junctions and single settable molecular switches that can be electronically configured for logic gates. Molecule-specific electronic switching has also been reported for several of these device structures, including nanopores containing oligo(phenylene ethynylene monolayers, and planar junctions incorporating rotaxane and catenane monolayers for the construction and operation of complex molecular machines. A specific electrically driven surface mounted molecular rotor is described in detail in this review. The rotor is comprised of a monolayer of redox-active ligated copper compounds sandwiched between a gold electrode and a highly-doped P+ Si. This electrically driven sandwich-type monolayer molecular rotor device showed an on/off ratio of approximately 104, a read window of about 2.5 V, and a retention time of greater than 104 s. The rotation speed of this type of molecular rotor has been reported to be in the picosecond timescale, which provides a potential of high switching speed applications. Current-voltage spectroscopy (I-V revealed a temperature-dependent negative differential resistance (NDR associated with the device. The analysis of the device

  20. Kiowa Creek Switching Station

    Energy Technology Data Exchange (ETDEWEB)

    1990-03-01

    The Western Area Power Administration (Western) proposes to construct, operate, and maintain a new Kiowa Creek Switching Station near Orchard in Morgan County, Colorado. Kiowa Creek Switching Station would consist of a fenced area of approximately 300 by 300 feet and contain various electrical equipment typical for a switching station. As part of this new construction, approximately one mile of an existing 115-kilovolt (kV) transmission line will be removed and replaced with a double circuit overhead line. The project will also include a short (one-third mile) realignment of an existing line to permit connection with the new switching station. In accordance with the Council on Environmental Quality (CEQ) regulations for implementing the procedural provisions of the National Environmental Policy Act of 1969 (NEPA), 40 CFR Parts 1500--1508, the Department of Energy (DOE) has determined that an environmental impact statement (EIS) is not required for the proposed project. This determination is based on the information contained in this environmental assessment (EA) prepared by Western. The EA identifies and evaluates the environmental and socioeconomic effects of the proposed action, and concludes that the advance impacts on the human environment resulting from the proposed project would not be significant. 8 refs., 3 figs., 1 tab.

  1. High PRF high current switch

    Science.gov (United States)

    Moran, Stuart L.; Hutcherson, R. Kenneth

    1990-03-27

    A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

  2. Operative and endovascular management of extracranial vertebral artery aneurysm in Ehlers-Danlos syndrome:a clinical dilemma--case report and literature review.

    LENUS (Irish Health Repository)

    Sultan, Sherif

    2002-01-01

    The most prevalent lesion of the vertebral artery is an atheromatous plaque located at its origin from the subclavian artery. A case of successful management of a symptomatic vertebral artery aneurysm due to Ehlers-Danlos syndrome is reported. The patient had asymptomatic posterior intracerebral artery dissection on the contralateral side. A common carotid artery to V-3 segment bypass using reversed saphenous vein graft was carried out. Avulsion of the V-2 segment occurred peroperatively and endovascular coil embolization of the vertebral artery aneurysm was performed. Endovascular equipment and training must be in the armamentarium of vascular surgeons as more complex cases are being treated, which demands new approaches for ultimate clinical success. This unique case outlines what might unexpectedly occur. Endovascular intervention as an adjuvant procedure provides a satisfactory outcome in what could have been a catastrophe.

  3. Foreign Operation Methods

    DEFF Research Database (Denmark)

    Welch, Lawrence S.; Benito, Gabriel R. G.; Petersen, Bent

    Introduction and theory -- Introduction -- Theoretical approaches -- Modes of operation -- Franchising -- Licensing -- Management contracts -- International subcontracting -- Project operations -- Exports -- Alliances -- Foreign direct investment -- Strategies -- Mode switching and stretching...

  4. Surgery for transposition of great arteries: A historical perspective

    Directory of Open Access Journals (Sweden)

    Supreet P Marathe

    2015-01-01

    Full Text Available The history of surgery for transposition of great arteries (TGA has paralleled the history of cardiac surgery. In fact, it began before the birth of open heart surgery when the palliative Blalock-Hanlon septectomy was first performed in 1948. The atrial switch, which was an attempt to correct the physiology of transposition, had significant shortcomings. The arterial switch sought to address them. This has emerged as an anatomically as well as physiologically appropriate solution. Today we continue to pursue technical refinements as well as try to expand the indications of the arterial switch. This review traces the various milestones in this perpetual journey.

  5. Thermal management and performance evaluation of a dual bi-directional, soft-switched IGBT-based inverter for the 1st autonomous microgrid power system in Taiwan under various operating conditions

    Science.gov (United States)

    Chang, Tien-Chan; Fuh, Yiin-Kuen; Lu, Hong-Yi; Tu, Sheng-Xun

    2016-06-01

    The thermal management of the inverter system is of great importance since very high voltage/current will be switched intermittently and/or continuously and high temperature is excruciably detrimental to the service life of electronics, especially for the switching devices such as insulated gate bipolar transistor (IGBT). In this study, a newly developed dual bi-directional IGBT-based inverter in conjunction with autonomous microgrid system is investigated with particular focus on the thermal management and performance evaluation under various operation conditions. Locally enhanced heat transfer approach such as oblique orientation and heat dissipating materials are experimentally investigated. The studied inverter system is initially packaged by a galvanized steel plate (size 62 × 48 × 18 cm) and the switching power is set in the range of 0.5-3 kW. The module is operated at the switching and pulse frequencies of 60 Hz and 20 kHz, respectively. The adoption of heat dissipating material in either paste or film form had experimentally shown to possess the flexibility tailoring heat transfer performance locally. Experimental studies of heat dissipating film with various hotspot scenarios showed that the temperature difference can be appreciably reduced as much as 13.1 and 15.4 °C, respectively with facilitation of one- and two-layers of heat dissipating film. From the measurement results, the measured peak temperature is highly dominated by the thickness of heat dissipating film, showing the dominance of thickness-dependent thermal resistance and resultant heat accumulation phenomena.

  6. Acute arterial occlusion - kidney

    Science.gov (United States)

    Acute renal arterial thrombosis; Renal artery embolism; Acute renal artery occlusion; Embolism - renal artery ... kidney can often result in permanent kidney failure. Acute arterial occlusion of the renal artery can occur after injury or trauma to ...

  7. Resistive switching in Ag-TiO2 contacts

    Science.gov (United States)

    Ghenzi, N.; Stoliar, P.; Fuertes, M. C.; Marlasca, F. G.; Levy, P.

    2012-08-01

    We study the electric pulse induced resistance switching of TiO2-Ag contacts at room temperature, exploring both unipolar and bipolar switching modes. Initially we observed unipolar response. After hundred pulsing cycles the unipolar switching response vanishes but the device can still be operated in bipolar switching regime. The underlying mechanism for resistance switching is modeled in terms of formation and rupture of filament, and movement of oxygen vacancies.

  8. Resistive switching in Ag-TiO{sub 2} contacts

    Energy Technology Data Exchange (ETDEWEB)

    Ghenzi, N., E-mail: ghenzi@cnea.gov.ar [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, (1650) San Martin, Pcia. de Buenos Aires (Argentina); Stoliar, P. [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, (1650) San Martin, Pcia. de Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Campus Migueletes, UNSAM, Pcia. de Buenos Aires (Argentina); Fuertes, M.C. [Gerencia Quimica, CAC, CNEA, (1650) San Martin, Pcia. de Buenos Aires (Argentina); Marlasca, F.G.; Levy, P. [Gerencia de Investigacion y Aplicaciones, CAC, CNEA, (1650) San Martin, Pcia. de Buenos Aires (Argentina)

    2012-08-15

    We study the electric pulse induced resistance switching of TiO{sub 2}-Ag contacts at room temperature, exploring both unipolar and bipolar switching modes. Initially we observed unipolar response. After hundred pulsing cycles the unipolar switching response vanishes but the device can still be operated in bipolar switching regime. The underlying mechanism for resistance switching is modeled in terms of formation and rupture of filament, and movement of oxygen vacancies.

  9. Dynamic actuation methods for capacitive MEMS shunt switches

    Science.gov (United States)

    Khater, M. E.; Vummidi, K.; Abdel-Rahman, E. M.; Nayfeh, A. H.; Raman, S.

    2011-03-01

    We develop dynamic actuation methods for capacitive MEMS shunt switches. We show that the dynamic actuation voltage is significantly less than the static actuation voltage and demonstrate 60% reduction in the actuation voltage. We also show that this reduction in the actuation voltage depends on the specific dynamic switching technique adopted. For a given operating condition, the minimum realizable switching time is that obtained using static switching. However, we developed a dynamic switching method that yields comparable switching time to that minimum. We also found that squeeze-film damping is the dominant damping mechanism for a shunt switch with a relatively slender bridge (aspect ratio of 11:1).

  10. A new Zero-Voltage-Transition PWM switching cell

    Energy Technology Data Exchange (ETDEWEB)

    Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

    1997-12-31

    In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.

  11. Multiuser Switched Diversity Scheduling Schemes

    CERN Document Server

    Shaqfeh, Mohammad; Alouini, Mohamed-Slim

    2012-01-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback sys...

  12. 股腘动脉血管搭桥术的中西医结合围手术期处理%The Perioperative Care of the Femoral Popliteal Artery Vascular Bypass Operation using Combination of Chinese and Western Medicine

    Institute of Scientific and Technical Information of China (English)

    王秋风; 狄长安

    2013-01-01

    目的:总结股腘动脉人工血管搭桥术治疗股浅动脉闭塞症的中西医结合围手术期处理经验.方法:观察62例股浅动脉闭塞症股腘动脉人工血管搭桥术的中西医结合围手术期处理对疗效的影响.结果:足背动脉搏动恢复,症状消失46例,症状明显改善16例,术后足趾溃疡愈合10例,第一、二趾截趾4例.结论:中西医结合围手术期处理是股腘动脉人工血管搭桥术康复过程中不可忽视的重要环节.%Objective:To summarize the perioperative care experience of combination of Chinese and western medicine on the femoral popliteal artery vascular bypass operation in the treatment of strands of shallow atherosclerosis block. Methods: The impact of perioperative care of Chinese and western medicine on femoral popliteal artery vascular bypass operation for 62 patients with strands of shallow arterial occlusive disease was observed. Results: In terms of pulsation of foot dorsal artery, 46 patients had symptoms disappeared, 16 patients significantly improved, 10 patients had toes ulcer healed, 4 patients had cut the first or the second toes. Conclusion:The perioperative care of combination of Chinese and western medicine is an innegligible important link in the rehabilitation process of the femoral popliteal artery vascular bypass operation.

  13. Switched steerable multiple beam antenna system

    Science.gov (United States)

    Iwasaki, Richard S. (Inventor)

    1988-01-01

    A steerable multibeam five element cross-feed cluster antenna system is described. The feed power is divided into five branches. Each branch includes a switching network comprised of a plurality of time delay elements each individually controlled by a respective electromagnetic latching switch. Frequency independent individual two-dimensional beam steering at intermediate (IF) scanning frequencies is thereby provided wherein discrete incremental time delays are introduced by the switching networks into each branch and the signals recombined thereafter to form each beam. The electromagnetic latched switching reduces power consumption and permits higher power switching and reciprocal coincident tranmsit and receive operation. Frequency independence due to incremental time delay switching permits coincident reciprocal operation and steering for transmit-receive signal paths carrying different transmit-receive frequencies. Diagonal quarter wave plates in the waveguides alter polarization from the circular to orthogonal linear to provide transmitter-receiver isolation.

  14. Patients undergoing elective coronary artery bypass grafting exhibit poor pre-operative intakes of fruit, vegetables, dietary fibre, fish and vitamin D.

    Science.gov (United States)

    Ruiz-Núñez, B; van den Hurk, G H A M; de Vries, J H M; Mariani, M A; de Jongste, M J L; Dijck-Brouwer, D A J; Muskiet, F A J

    2015-05-14

    CHD may ensue from chronic systemic low-grade inflammation. Diet is a modifiable risk factor for both, and its optimisation may reduce post-operative mortality, atrial fibrillation and cognitive decline. In the present study, we investigated the usual dietary intakes of patients undergoing elective coronary artery bypass grafting (CABG), emphasising on food groups and nutrients with putative roles in the inflammatory/anti-inflammatory balance. From November 2012 to April 2013, we approached ninety-three consecutive patients (80% men) undergoing elective CABG. Of these, fifty-five were finally included (84% men, median age 69 years; range 46-84 years). The median BMI was 27 (range 18-36) kg/m(2). The dietary intake items were fruits (median 181 g/d; range 0-433 g/d), vegetables (median 115 g/d; range 0-303 g/d), dietary fibre (median 22 g/d; range 9-45 g/d), EPA+DHA (median 0.14 g/d; range 0.01-1.06 g/d), vitamin D (median 4.9 μg/d; range 1.9-11.2 μg/d), saturated fat (median 13.1% of energy (E%); range 9-23 E%) and linoleic acid (LA; median 6.3 E%; range 1.9-11.3 E%). The percentages of patients with dietary intakes below recommendations were 62% (fruits; recommendation 200 g/d), 87 % (vegetables; recommendation 150-200 g/d), 73% (dietary fibre; recommendation 30-45 g/d), 91% (EPA+DHA; recommendation 0.45 g/d), 98% (vitamin D; recommendation 10-20 μg/d) and 13% (LA; recommendation 5-10 E%). The percentages of patients with dietary intakes above recommendations were 95% (saturated fat; recommendation < 10 E%) and 7% (LA). The dietary intakes of patients proved comparable with the average nutritional intake of the age- and sex-matched healthy Dutch population. These unbalanced pre-operative diets may put them at risk of unfavourable surgical outcomes, since they promote a pro-inflammatory state. We conclude that there is an urgent need for intervention trials aiming at rapid improvement of their diets to reduce peri-operative risks.

  15. Application Criteria for Nine-Switch Power Conversion Systems with Improved Thermal Performance

    DEFF Research Database (Denmark)

    Qin, Zian; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    Nine-switch converter is a reduced-switch equivalence of the widely used twelve-switch back-to-back converter. Like other reduced-switch topologies, the nine-switch converter experiences operating constraints, which may limit its efficiency. This is however not universal, meaning losses of the ni...

  16. Lean-Burn Stationary Natural Gas Reciprocating Engine Operation with a Prototype Miniature Diode Side Pumped Passively Q-switched Laser Spark Plug

    Energy Technology Data Exchange (ETDEWEB)

    McIntyre, D.L.; Woodruff, S.D.; McMillian, M.H.; Richardson, S.W.; Gautam, Mridul

    2008-04-01

    To meet the ignition system needs of large bore lean burn stationary natural gas engines a laser diode side pumped passively Q-switched laser igniter was developed and used to ignite lean mixtures in a single cylinder research engine. The laser design was produced from previous work. The in-cylinder conditions and exhaust emissions produced by the miniaturized laser were compared to that produced by a laboratory scale commercial laser system used in prior engine testing. The miniaturized laser design as well as the combustion and emissions data for both laser systems was compared and discussed. It was determined that the two laser systems produced virtually identical combustion and emissions data.

  17. Transposition of the great arteries

    Directory of Open Access Journals (Sweden)

    Castela Eduardo

    2008-10-01

    required soon after birth. Surgical correction is performed at a later stage. Usually, the Jatene arterial switch operation is the procedure of choice. Whenever this operation is not feasible, adequate alternative surgical approach should be implemented. With the advent of newer and improved surgical techniques and post operative intensive care, the long-term survival is approximately 90% at 15 years of age. However, the exercise performance, cognitive function and quality of life may be impaired.

  18. Portable Userspace Virtual Filesystem Switch

    Directory of Open Access Journals (Sweden)

    Łukasz Faber

    2013-01-01

    Full Text Available Multiple different filesystems — including disk-based, network, distributed, abstract — arean integral part of every operating system. They are usually written as kernel modules and abstracted to the user via a virtual filesystem switch. In this paper we analyse the feasibility of reimplementing the virtual filesystem switch as a userspace daemon and applicability of this approach in real-life usage. Such reimplementation will require a way to virtualise processes behaviour related to filesystem operations. The problem is non-trivial, as we assume limited capabilities of the VFS switch implemented in userspace. We present a layered architecture comprising of a monitoring process, the VFS abstraction and real filesystem implementations. All working in userspace. Then, we evaluate this solution in four areas: portability, feasibility, usability and performance. Our results demonstrate possible gains in using the userspace-based approach with monolithic kernels, but also underline problems that are encountered in this approach.

  19. K-Band Latching Switches

    Science.gov (United States)

    Piotrowski, W. S.; Raue, J. E.

    1984-01-01

    Design, development, and tests are described for two single-pole-double-throw latching waveguide ferrite switches: a K-band switch in WR-42 waveguide and a Ka-band switch in WR-28 waveguide. Both switches have structurally simple junctions, mechanically interlocked without the use of bonding materials; they are impervious to the effects of thermal, shock, and vibration stresses. Ferrite material for the Ka-band switch with a proper combination of magnetic and dielectric properties was available and resulted in excellent low loss, wideband performance. The high power handling requirement of the K-band switch limited the choice of ferrite to nickel-zinc compositions with adequate magnetic properties, but with too low relative dielectric constant. The relative dielectric constant determines the junction dimensions for given frequency responses. In this case the too low value unavoidably leads to a larger than optimum junction volume, increasing the insertion loss and restricting the operating bandwidth. Efforts to overcome the materials-related difficulties through the design of a composite junction with increased effective dielectric properties efforts to modify the relative dielectric constant of nickel-zinc ferrite are examined.

  20. K-band latching switches

    Science.gov (United States)

    Piotrowski, W. S.; Raue, J. E.

    1984-05-01

    Design, development, and tests are described for two single-pole-double-throw latching waveguide ferrite switches: a K-band switch in WR-42 waveguide and a Ka-band switch in WR-28 waveguide. Both switches have structurally simple junctions, mechanically interlocked without the use of bonding materials; they are impervious to the effects of thermal, shock, and vibration stresses. Ferrite material for the Ka-band switch with a proper combination of magnetic and dielectric properties was available and resulted in excellent low loss, wideband performance. The high power handling requirement of the K-band switch limited the choice of ferrite to nickel-zinc compositions with adequate magnetic properties, but with too low relative dielectric constant. The relative dielectric constant determines the junction dimensions for given frequency responses. In this case the too low value unavoidably leads to a larger than optimum junction volume, increasing the insertion loss and restricting the operating bandwidth. Efforts to overcome the materials-related difficulties through the design of a composite junction with increased effective dielectric properties efforts to modify the relative dielectric constant of nickel-zinc ferrite are examined.

  1. Optical packet switching without packet alignment

    DEFF Research Database (Denmark)

    Hansen, Peter Bukhave; Danielsen, Søren Lykke; Stubkjær, Kristian

    1998-01-01

    Operation without packet alignment of an all-optical packet switch is proposed and predicted feasible through a detailed traffic analysis. Packet alignment units are eliminated resulting in a simple switch architecture while optimal traffic performance is maintained through the flexibility provided...

  2. Switched on!

    CERN Multimedia

    2008-01-01

    Like a star arriving on stage, impatiently followed by each member of CERN personnel and by millions of eyes around the world, the first beam of protons has circulated in the LHC. After years in the making and months of increasing anticipation, today the work of hundreds of people has borne fruit. WELL DONE to all! Successfully steered around the 27 kilometres of the world’s most powerful particle accelerator at 10:28 this morning, this first beam of protons circulating in the ring marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. "It’s a fantastic moment," said the LHC project leader Lyn Evans, "we can now look forward to a new era of understanding about the origins and evolution of the universe". Starting up a major new particle accelerator takes much more than flipping a switch. Thousands of individual elements have to work in harmony, timings have to be synchronize...

  3. Wireless Nanoionic-Based Radio Frequency Switch

    Science.gov (United States)

    Nessel, James A. (Inventor); Miranda, Felix A (Inventor)

    2016-01-01

    A nanoionic switch connected to one or more rectenna modules is disclosed. The rectenna module is configured to receive a wireless signal and apply a first bias to change a state of the nanoionic switch from a first state to a second state. The rectenna module can receive a second wireless signal and apply a second bias to change the nanoionic switch from the second state back to the first state. The first bias is generally opposite of the first bias. The rectenna module accordingly permits operation of the nanoionic switch without onboard power.

  4. Multipath packet switch using packet bundling

    DEFF Research Database (Denmark)

    Berger, Michael Stubert

    2002-01-01

    The basic concept of packet bundling is to group smaller packets into larger packets based on, e.g., quality of service or destination within the packet switch. This paper presents novel applications of bundling in packet switching. The larger packets created by bundling are utilized to extend...... switching capacity by use of parallel switch planes. During the bundling operation, packets will experience a delay that depends on the actual implementation of the bundling and scheduling scheme. Analytical results for delay bounds and buffer size requirements are presented for a specific scheduling...

  5. Simplified design of switching power supplies

    CERN Document Server

    Lenk, John

    1995-01-01

    * Describes the operation of each circuit in detail * Examines a wide selection of external components that modify the IC package characteristics * Provides hands-on, essential information for designing a switching power supply Simplified Design of Switching Power Supplies is an all-inclusive, one-stop guide to switching power-supply design. Step-by-step instructions and diagrams render this book essential for the student and the experimenter, as well as the design professional. Simplified Design of Switching Power Supplies concentrates on the use of IC regulators. All popular forms of swit

  6. Gold nanobipyramids as a saturable absorber for passively Q-switched Yb-doped fiber laser operation at 1.06 µm

    Science.gov (United States)

    Zhang, Huanian; Li, Bowen; Liu, Jie

    2017-02-01

    In this letter, gold nanobipyramids (Au-NBPs) are prepared using a seed-mediated growth method. The longitudinal surface plasmon resonance (SPR) absorption peak of the Au-NBPs is located at 1068 nm by controlling the aspect of the materials. To verify the absorption properties of the Au-NBP saturable absorber (SA), a passively Q-switched Yb-doped fiber laser is demonstrated. The maximum average output power of 3.33 mW is obtained under a pumped power of 340 mW. The minimum pulse width is 2.6 µs at a pulse repetition rate of 66.3 kHz. The results prove that Au-NBP are a promising SA with the potential for important applications in the field of pulse lasers.

  7. MEMS switches having non-metallic crossbeams

    Science.gov (United States)

    Scardelletti, Maximillian C (Inventor)

    2009-01-01

    A RF MEMS switch comprising a crossbeam of SiC, supported by at least one leg above a substrate and above a plurality of transmission lines forming a CPW. Bias is provided by at least one layer of metal disposed on a top surface of the SiC crossbeam, such as a layer of chromium followed by a layer of gold, and extending beyond the switch to a biasing pad on the substrate. The switch utilizes stress and conductivity-controlled non-metallic thin cantilevers or bridges, thereby improving the RF characteristics and operational reliability of the switch. The switch can be fabricated with conventional silicon integrated circuit (IC) processing techniques. The design of the switch is very versatile and can be implemented in many transmission line mediums.

  8. High power ferrite microwave switch

    Science.gov (United States)

    Bardash, I.; Roschak, N. K.

    1975-01-01

    A high power ferrite microwave switch was developed along with associated electronic driver circuits for operation in a spaceborne high power microwave transmitter in geostationary orbit. Three units were built and tested in a space environment to demonstrate conformance to the required performance characteristics. Each unit consisted of an input magic-tee hybrid, two non-reciprocal latching ferrite phase shifters, an out short-slot 3 db quadrature coupler, a dual driver electronic circuit, and input logic interface circuitry. The basic mode of operation of the high power ferrite microwave switch is identical to that of a four-port, differential phase shift, switchable circulator. By appropriately designing the phase shifters and electronic driver circuits to operate in the flux-transfer magnetization mode, power and temperature insensitive operation was achieved. A list of the realized characteristics of the developed units is given.

  9. Data center coolant switch

    Energy Technology Data Exchange (ETDEWEB)

    Iyengar, Madhusudan K.; Parida, Pritish R.; Schultz, Mark D.

    2015-10-06

    A data center cooling system is operated in a first mode; it has an indoor portion wherein heat is absorbed from components in the data center, and an outdoor heat exchanger portion wherein outside air is used to cool a first heat transfer fluid (e.g., water) present in at least the outdoor heat exchanger portion of the cooling system during the first mode. The first heat transfer fluid is a relatively high performance heat transfer fluid (as compared to the second fluid), and has a first heat transfer fluid freezing point. A determination is made that an appropriate time has been reached to switch from the first mode to a second mode. Based on this determination, the outdoor heat exchanger portion of the data cooling system is switched to a second heat transfer fluid, which is a relatively low performance heat transfer fluid, as compared to the first heat transfer fluid. It has a second heat transfer fluid freezing point lower than the first heat transfer fluid freezing point, and the second heat transfer fluid freezing point is sufficiently low to operate without freezing when the outdoor air temperature drops below a first predetermined relationship with the first heat transfer fluid freezing point.

  10. A new Zero-Current-Transition PWM switching cell

    Energy Technology Data Exchange (ETDEWEB)

    Grigore, V. [Electronics and Telecommunications Faculty, `Politechnica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

    1997-12-31

    In this paper a new Zero-Current-Transition (ZCT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus as auxiliary circuit. The auxiliary circuit is inactive during the ON ad OFF intervals of the switches in the normal PWM switch. The transitions between the two states are controlled by the auxiliary circuit. Prior to turn-off, the current through the active switch in the PWM cell is forced to zero, thus the turn-off losses of the active switch are practically eliminated. At turn-on the auxiliary circuit slows down the growing rate of the current through the main switch. Thus, turn-on losses are also very much reduced. The active switch operates under ZCT conditions, the passive switch (diode) has a controlled reverse recovery, while the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 3 refs.

  11. Ultra High-Speed Radio Frequency Switch Based on Photonics.

    Science.gov (United States)

    Ge, Jia; Fok, Mable P

    2015-11-26

    Microwave switches, or Radio Frequency (RF) switches have been intensively used in microwave systems for signal routing. Compared with the fast development of microwave and wireless systems, RF switches have been underdeveloped particularly in terms of switching speed and operating bandwidth. In this paper, we propose a photonics based RF switch that is capable of switching at tens of picoseconds speed, which is hundreds of times faster than any existing RF switch technologies. The high-speed switching property is achieved with the use of a rapidly tunable microwave photonic filter with tens of gigahertz frequency tuning speed, where the tuning mechanism is based on the ultra-fast electro-optics Pockels effect. The RF switch has a wide operation bandwidth of 12 GHz and can go up to 40 GHz, depending on the bandwidth of the modulator used in the scheme. The proposed RF switch can either work as an ON/OFF switch or a two-channel switch, tens of picoseconds switching speed is experimentally observed for both type of switches.

  12. RF-MEMS capacitive switches with high reliability

    Science.gov (United States)

    Goldsmith, Charles L.; Auciello, Orlando H.; Carlisle, John A.; Sampath, Suresh; Sumant, Anirudha V.; Carpick, Robert W.; Hwang, James; Mancini, Derrick C.; Gudeman, Chris

    2013-09-03

    A reliable long life RF-MEMS capacitive switch is provided with a dielectric layer comprising a "fast discharge diamond dielectric layer" and enabling rapid switch recovery, dielectric layer charging and discharging that is efficient and effective to enable RF-MEMS switch operation to greater than or equal to 100 billion cycles.

  13. 46 CFR 131.805 - General alarm bell, switch.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false General alarm bell, switch. 131.805 Section 131.805 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.805 General alarm bell, switch. The switch in...

  14. 49 CFR 236.732 - Controller, circuit; switch.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Controller, circuit; switch. 236.732 Section 236... § 236.732 Controller, circuit; switch. A device for opening and closing electric circuits, operated by a rod connected to a switch, derail or movable-point frog....

  15. Influence of Baseline Characteristics, Operative Conduct and Postoperative Course on 30-day Outcomes of Coronary Artery Bypass Grafting among Patients with Left Ventricular Dysfunction: Results from the Surgical Treatment for Ischemic Heart Failure (STICH) Trial

    Science.gov (United States)

    Wrobel, Krzysztof; Stevens, Susanna R.; Jones, Robert H.; Selzman, Craig H.; Lamy, Andre; Beaver, Thomas M.; Djokovic, Ljubomir T.; Wang, Nan; Velazquez, Eric J.; Sopko, George; Kron, Irving L.; DiMaio, J. Michael; Michler, Robert E.; Lee, Kerry L.; Yii, Michael; Leng, Chua Yeow; Zembala, Marian; Rouleau, Jean L.; Daly, Richard C.; Al-Khalidi, Hussein R.

    2015-01-01

    Background Patients with severe left ventricular (LV) dysfunction, ischemic heart failure and coronary artery disease (CAD) suitable for coronary artery bypass grafting (CABG) are at higher risk for surgical morbidity and mortality. Paradoxically, those patients with the most severe coronary artery disease and ventricular dysfunction who derive the greatest clinical benefit from CABG are also at the greatest operative risk, which makes decision-making regarding whether to proceed to surgery difficult in such patients. To better inform such decision-making, we analyzed the STICH CABG population for detailed information on perioperative risk and outcomes. Methods and Results In both STICH trials (hypotheses), 2136 patients with a left ventricular ejection fraction (LVEF) ≤ 35% and coronary artery disease were allocated to medical therapy, CABG plus medical therapy or CABG with surgical ventricular reconstruction (SVR). Relationships of baseline characteristics and operative conduct with morbidity and mortality at 30 days were evaluated. There were a total of 1460 patients who received surgery, and 346 of them (roughly, one-quarter) of these high-risk patients developed a severe complication within 30 days. Worsening renal insufficiency, cardiac arrest with cardiopulmonary resuscitation, and ventricular arrhythmias were the most frequent complications and those most commonly associated with death. Mortality at 30 days was 5.1% and was generally preceded by a serious complication (65 of 74 deaths). LV size, renal dysfunction, advanced age, and atrial fibrillation/flutter were significant preoperative predictors of mortality within 30 days. Cardiopulmonary bypass time was the only independent surgical variable predictive of 30-day mortality. Conclusions CABG can be performed with relatively low 30-day mortality in patients with LV dysfunction. Serious postoperative complications occurred in nearly 1 in 4 patients and were associated with mortality. Clinical Trial

  16. Zero-voltage switching technique in dc/dc converters

    Science.gov (United States)

    Liu, Kwang-Hwa; Lee, Fred C. Y.

    1990-07-01

    A novel resonant switch operating under the principle of zero-voltage switching is presented. In contrast to the zero-current switching, this technique eliminates the switching loss and dv/dt noise due to the discharging of MOSFET junction capacitances and the reverse recovery of diodes, and enables the converters to operate at high frequencies. A dc analysis of the converter is carried out. The duality relationship between the zero-current switching technique and the zero-voltage switching technique is derived. The two techniques are compared using an example showing the duality between a current-mode quasi-resonant Buck converter and a voltage-mode quasi-resonant boost converter. A 5-MHz 50 V to 5 V flyback converter employing the zero-voltage switching technique has been implemented. The circuit contains the smallest number of components possible, and yet maintains high efficiency at high switching frequency.

  17. Carotid artery surgery

    Science.gov (United States)

    Carotid endarterectomy; CAS surgery; Carotid artery stenosis - surgery; Endarterectomy - carotid artery ... through the catheter around the blocked area during surgery. Your carotid artery is opened. The surgeon removes ...

  18. Demonstration of reconfigurable joint orbital angular momentum mode and space switching.

    Science.gov (United States)

    Liu, Jun; Wang, Jian

    2016-11-21

    We propose and demonstrate space-selective switch functions employing orbital angular momentum (OAM) modes in the space domain for switching network. One is the switching among different OAM modes having different spatial phase structures, called OAM mode switching. The other is the switching among different space locations, called space switching. The switching operation mechanism relies on linear optics. Reconfigurable 4 × 4 OAM mode switching, space switching, and joint OAM mode and space switching fabric using a single spatial light modulator (SLM) are all demonstrated in the experiment. In addition, the presented OAM-incorporated space-selective switch might be further extended to N × N joint OAM mode and space switching with fast response, scalability, cascading ability and compability to facilitate robust switching applications.

  19. 基于调度倒闸操作流程及标准操作程序的操作安全防误应用%Safety Mistake Preventing Application of Dispatching Operation Based on Scheduling Switching Operation Procedures and Standard Operating Procedures

    Institute of Scientific and Technical Information of China (English)

    樊启俊; 胡伟; 王兴存; 刘军

    2015-01-01

    An analysis is made of the dispatching operation business security mistake prevention management specification requirements and the current mainstream development mode of security anti-false application.It is proposed that the relevant anti-error safety application mode of anti-fault security check be called in different links of the procedures with the scheduling of switching operation procedures and the standard operation procedure (SOP) as the main line.And a detailed description of specific design and implementation is presented.The anti-error management of SOP is seamlessly blended with anti-false technology such as safety checking and calculation,realizing the anti-error safety of the whole procedure of dispatching operation business.%分析了调度操作业务安全防误管理的规范要求和当前主流的安全防误应用建设模式,提出了以调度倒闸操作流程及标准操作程序(SOP)为主线,在流程的不同环节调用相关安全防误校核的安全防误应用模式,并详细阐述了具体设计实现,将 SOP 的管理防误与安全校核计算等技术防误无缝融合,实现了调度操作业务的全过程安全防误。

  20. Latching micro optical switch

    Science.gov (United States)

    Garcia, Ernest J; Polosky, Marc A

    2013-05-21

    An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

  1. Neuromorphic atomic switch networks.

    Directory of Open Access Journals (Sweden)

    Audrius V Avizienis

    Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

  2. Stable mode-locked operation of a low repetition rate diode-pumped Nd:GdVO4 laser by combining quadratic polarisation switching and a semiconductor saturable absorber mirror.

    Science.gov (United States)

    Gerhard, Christoph; Druon, Frédéric; Georges, Patrick; Couderc, Vincent; Leproux, Philippe

    2006-08-07

    In this paper, we present the mode-locked operation of an ultra-robustly stabilised Nd:GdVO(4) laser with low repetition rate by combining quadratic polarisation switching and a semiconductor saturable absorber mirror (SESAM). In addition, similar experiment was also done with Nd:YVO(4). For Nd:GdVO(4), 16-ps pulses at 1063 nm with a repetition rate of 3.95 MHz have been obtained for a laser average output power of 1.4 W. For Nd:YVO(4), the performance was 2.5 W of average power for 15-ps pulses at 1064 nm. Moreover, we demonstrate experimentally the advantage of combining these two passive mode locking techniques in terms of stability ranges. We show how the dual mode-locking technique is crucial to obtain a stable and long-term mode-locked regime in our case of a diode-pumped Nd:GdVO(4) laser operating at low repetition rate and more generally how this dual mode-locking technique improves the stability range of the mode-locked operation giving more flexibility on different parameters.

  3. Coronary artery fistula

    Science.gov (United States)

    Congenital heart defect - coronary artery fistula; Birth defect heart - coronary artery fistula ... A coronary artery fistula is often congenital, meaning that it is present at birth. It generally occurs when one of the coronary arteries ...

  4. Study on switched reluctance generator

    Institute of Scientific and Technical Information of China (English)

    潘再平; 金英; 张慧

    2004-01-01

    The linear and non-linear math models of the switched reluctance generator (SRG) in generator mode were established in this work. The phase current and energy conversion process during generator operation were simulated by the linear math model. The non-linear math model was used to analyze the characteristics of the SRG operation in self-excitation mode and in separately-excitation mode. Some important findings on how the SRG is operated and controlled were obtained in this study, which provides theoretical basis for further design and experimental study.

  5. The Difficulties in Determining Time of the Operation in the Total Corrected Transposition of the Great Arteries with Severe Left AV Valve Regurgitation: Case Report

    Directory of Open Access Journals (Sweden)

    Erden İ et al.

    2010-03-01

    Full Text Available Congenitally corrected transposition of the great arteries (L-TGA is characterized by discordance between the atria and ventricles, as well as between the ventricles and the great arteries. As a result, the morphologic right ventricle lies to the left of the morphologic left ventricle and becomes the systemic ventricle. The morphologic right ventricle gives rise to the aorta, which is anterior of the pulmonary artery. As a result of discordance at both the atrioventricular (AV and the great vessel level, physiologic blood flow remains normal. It was shown that the decreased RV functions are related with increased mortality rates in long term follow up. Most of these patients have RV failure due to abnormal pressure load of systemic RV, imbalance between O2 supply and myocardial demand and development of systemic AV valvular regurgitation in most of the patients. Therefore, the most important and difficult point in the follow up of these patients is evaluation of RV functions and degree of systemic AV valve regurgitation. In this review, we discussed the difficulties in the diagnosis and treatment of these patients in the light of a typical TGA case.

  6. Remote switch actuator

    Science.gov (United States)

    Haas, Edwin Gerard; Beauman, Ronald; Palo, Jr., Stefan

    2013-01-29

    The invention provides a device and method for actuating electrical switches remotely. The device is removably attached to the switch and is actuated through the transfer of a user's force. The user is able to remain physically removed from the switch site obviating need for protective equipment. The device and method allow rapid, safe actuation of high-voltage or high-current carrying electrical switches or circuit breakers.

  7. Perancangan Switch Matrik Besar Menggunakan Array Switch Analog Zarlink

    OpenAIRE

    2009-01-01

    Secara tradisional, perancangan sebuah switch matrik yang besar dilakukan dengan menggunakan switch-switch elektromekanik. Dengan demikian, banyak bagian yang bergerak yang digunakan untuk membangun switch matrik ini. Dengan kemajuan bidang elektronik, switch elektromekanik saat ini dapat digantikan dengan switch-switch semikonduktor yang ekivalen yang menawarkan solusi yang lebih ekonomis dan memiliki keandalan yang lebih baik. Rumpun switch crosspoint analog Zarlink dapat disusun dengan mud...

  8. Diode-pumped Q-switched Nd{sup 3+} : YAG laser operating in a wide temperature range without thermal stabilisation of pump diodes

    Energy Technology Data Exchange (ETDEWEB)

    Vainshenker, A E; Vilenskiy, A V; Kazakov, A A; Lysoy, B G; Mikhailov, L K; Pashkov, V A [Open Joint-Stock Company ' M.F. Stel' makh Polyus Research and Development Institute' , Moscow (Russian Federation)

    2013-02-28

    A model sample of a compact low-power-consumption Nd{sup 3+} : YAG laser emitting 20-mJ pulses with a pulse repetition rate up to 20 Hz (in cyclic duty) at a wavelength of 1064 nm is developed and studied. The laser is designed for operating at external temperatures from -40 to +50 deg C. This was achieved by using quasi-end diode pumping without thermal stabilisation of pump diodes. (laser optics 2012)

  9. Switched-capacitor isolated LED driver

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, Seth R.; Kline, Mitchell

    2016-03-22

    A switched-capacitor voltage converter which is particularly well-suited for receiving a line voltage from which to drive current through a series of light emitting diodes (LEDs). Input voltage is rectified in a multi-level rectifier network having switched capacitors in an ascending-bank configuration for passing voltages in uniform steps between zero volts up to full received voltage V.sub.DC. A regulator section, operating on V.sub.DC, comprises switched-capacitor stages of H-bridge switching and flying capacitors. A current controlled oscillator drives the states of the switched-capacitor stages and changes its frequency to maintain a constant current to the load. Embodiments are described for isolating the load from the mains, utilizing an LC tank circuit or a multi-primary-winding transformer.

  10. Gain and Efficiency of a Superconducting Microwave Compressor with a Switching Cavity in an Interference Switch

    Science.gov (United States)

    Artemenko, S. N.; Samoylenko, G. M.

    2016-11-01

    We study the processes of radiation output from a microwave storage cavity through a superconducting interference switch, which is based on a H-junction with a superconducting switching cavity connected to the side branch of the junction for various ways of controlling the parameters of the switching cavity. It is shown that efficient control over radiation output in such a switch can be achieved by varying the resonance frequency or Q-factor of the switching cavity, as well as by varying these parameters simultaneously. It is found that in the case of controlling the resonance frequency of the switching cavity, there exists an optimal interval of the frequency variation, within which the total efficiency and extraction efficiency are maximum. When the Q-factor of the switching cavity changes, the dependence of the total efficiency and extraction efficiency on the Q-factor has the monotonic character. The mixed regime of radiation output control is also studied. The envelopes of the output compressor pulses are plotted on the basis of recurrent relationships between the amplitudes of the waves in the system for three regimes of switch operation. It is shown that pulses with an almost rectangular shape of the envelope can be formed in the regime of controlling the switching cavity by varying the Q-factor. An example of possible realization of the switching cavity is considered.

  11. Improved Switching Function Model of Converter Suitable for Asymmetric Operating State%非对称运行状态下换流器改进开关函数模型

    Institute of Scientific and Technical Information of China (English)

    贠飞龙; 刘崇茹; 田鹏飞; 李越

    2016-01-01

    Accuracy of traditional switching function model of converter is significantly reduced in asymmetric operation mode. Commutation process in asymmetric operation mode is analyzed, considering impact of the 2nd harmonic in DC side during commutation. A calculation method for commutation overlap angle is proposed considering the 2nd harmonic component. An improved switching function model of converter is established, where valve conduction effects and unbalanced commutation overlap angles are taken into account. Calculation process is simplified by ignoring non-essential harmonics. Comparison of simulation results in PSCAD and calculation in MATLAB on DC voltages, AC currents and injected active and reactive powers shows that the proposed model is effective in asymmetric operation mode.%传统的换流器开关函数模型应用于非对称运行状态分析时,精度显著降低。详细分析了三相非对称运行状态下换流器的换相过程,并着重考虑了直流侧2次谐波电流对换相持续时间的影响,提出了考虑2次谐波电流影响的换相角计算方法。基于分析建立了考虑阀导通偏移和换相角不等的换流器改进开关函数模型,并通过忽略非必要次谐波简化了模型的计算过程。在 Matlab 中编程实现了提出的开关函数模型,并采用PSCAD中搭建的Cigre-Benchmark直流标准模型的仿真结果进行检验。分别在逆变侧和整流侧设置换流母线三相不对称,通过对比直流侧直流电压、换流母线三相注入电流及注入功率,验证了提出模型的有效性。

  12. Circuit switched optical networks

    DEFF Research Database (Denmark)

    Kloch, Allan

    2003-01-01

    Some of the most important components required for enabling optical networking are investigated through both experiments and modelling. These all-optical components are the wavelength converter, the regenerator and the space switch. When these devices become "off-the-shelf" products, optical cross...... are often considered as a part of the optical cross-connect, where also optical space switching is performed. Therefore, space switching based on both optical gates and interferometric switches is investigated. Moreover, an experiment including both space switching and wavelength conversion is carried out...

  13. Design of two-layer switching rule for stabilization of switched linear systems with mismatched switching

    Institute of Scientific and Technical Information of China (English)

    Dan MA

    2014-01-01

    A two-layer switching architecture and a two-layer switching rule for stabilization of switched linear control systems are proposed, under which the mismatched switching between switched systems and their candidate hybrid controllers can be allowed. In the low layer, a state-dependent switching rule with a dwell time constraint to exponentially stabilize switched linear systems is given;in the high layer, supervisory conditions on the mismatched switching frequency and the mismatched switching ratio are presented, under which the closed-loop switched system is still exponentially stable in case of the candidate controller switches delay with respect to the subsystems. Different from the traditional switching rule, the two-layer switching architecture and switching rule have robustness, which in some extend permit mismatched switching between switched subsystems and their candidate controllers.

  14. Total Arterial Revascularization with Internal Mammary Artery or Radial Artery Graft Configuration

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    To investigate the clinical use of π graft in total arterial revascularization and its outcomes, a retrospective analysis of 23 patients out of 1000 patients undergoing total arterial coronary bypass surgery with a π graft between September 1994 and December 2004 was performed. In the selected patients for the management of triple vessel disease with middle diagonal/intermediate ramus disease such that a skip with the left internal mammary artery (LIMA) or radial artery (RA),the main stem of π graft, to the left anterior descending coronary artery (LAD) will not work and the right internal mammary artery (RIMA) or right gastroepiploic artery (RGEA) cannot pick up the diagonal/intermediate ramus, hence the LAD and diagonal/intermediate ramus were grafted with a mini Y graft using the distal segment of LIMA, RIMA, RA or RGEA, together with the bilateral internal mammary artery (BIMA) or LIMA-RA T graft to compose π graft. Twenty-three patients (18 males, 5 females) underwent the π graft procedure. There were no deaths or episodes of myocardial infarction, stroke, and deep sternal wound infection. One patient required reopening for controlling bleeding. Until the end of 2004, during a mean follow-up of 81.0 ±28.4 months, no angina needing re-intervention or operative therapy or coronary related death occurred. In conclusion, in patients with specific coronary artery anatomy/stenosis, the BIMA (sometimes LIMA with RA or RGEA) π graft can be successfully performed for total arterial revascularization with good midterm outcomes.

  15. Low prevalence of significant carotid artery disease in Iranian patients undergoing elective coronary artery bypass

    Directory of Open Access Journals (Sweden)

    Karimi Fatemeh

    2007-01-01

    Full Text Available Abstract Background Coronary artery bypass grafting ranks as one of the most frequent operations worldwide. The presence of carotid artery stenosis may increase the stroke rate in the perioperative period. Routine preoperative noninvasive assessment of the carotid arteries are recommended in many institutions to reduce the stroke rate. Methods 271 consecutive patients undergoing coronary artery bypass grafting at Shaheed Madani hospital of Tabriz, Iran (age, 58.5 Y; 73.1% male underwent preoperative ultrasonography for assessment of carotid artery wall thickness. Results Plaque in right common, left common, right internal and left internal carotid arteries was detected in 4.8%, 7.4%, 43.2% and 42.1% of patients respectively. 5 patients (1.8% had significant ( Conclusion Consecutive Iranian patients undergoing elective coronary artery bypass surgery show a very low prevalence of significant carotid artery disease.

  16. Design of a switched reluctance generator

    Energy Technology Data Exchange (ETDEWEB)

    Heese, T.; Pyrhoenen, J.

    1996-12-31

    This report presents the design of a low voltage switched reluctance generator for variable speed applications showing the design of its construction and commutation unit. For the realisation of the control system the control strategy is presented. The principle and the theory of switched reluctance generators are described in this context. Also an overview of existing generator technology for these applications is given. The results gained suggest that switched reluctance machines can also advantageously be used as generators if the generating operation is considered within the design process. Compared with the existing technology a higher output power and efficiency is reached over the whole speed range. (orig.)

  17. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad

    2012-09-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  18. Decision maker based on atomic switches

    OpenAIRE

    Song-Ju Kim; Tohru Tsuruoka; Tsuyoshi Hasegawa; Masashi Aono; Kazuya Terabe; Masakazu Aono

    2016-01-01

    We propose a simple model for an atomic switch-based decision maker (ASDM), and show that, as long as its total number of metal atoms is conserved when coupled with suitable operations, an atomic switch system provides a sophisticated ``decision-making'' capability that is known to be one of the most important intellectual abilities in human beings. We considered a popular decision-making problem studied in the context of reinforcement learning, the multi-armed bandit problem (MAB); the probl...

  19. Continuous inhaled iloprost in a neonate with d-transposition of the great arteries and severe pulmonary arterial hypertension.

    Science.gov (United States)

    Dykes, John C; Torres, Marilyn; Alexander, Plato J

    2016-03-01

    This report describes the case of a neonate with d-transposition of the great arteries and severe pulmonary arterial hypertension stabilised in the post-operative period with continuous iloprost nebulisation. To our knowledge, this is the first documented method of treating post-operative severe pulmonary arterial hypertension with continuous inhaled iloprost in a patient with complex CHD. We found this method of delivering the drug very effective in stabilising haemodynamic swings in the setting of severe pulmonary arterial hypertension.

  20. Evaluation of adjusted central venous blood gases versus arterial blood gases of patients in post-operative paediatric cardiac surgical intensive care unit

    Directory of Open Access Journals (Sweden)

    Naveen G Singh

    2015-01-01

    Full Text Available Background and Aims: Central venous catheters are in situ in most of the intensive care unit (ICU patients, which may be an alternative for determining acid-base status and can reduce complications from prolonged arterial cannulation. The aim of this study was to examine the reliability between adjusted central venous blood gas (aVBG and arterial blood gas (ABG samples for pH, partial pressure of carbon-di-oxide (pCO2, bicarbonate (HCO3−, base excess (BE and lactates in paediatric cardiac surgical ICU. Methods: We applied blood gas adjustment rule, that is aVBG pH = venous blood gas (VBG pH +0.05, aVBG CO2 = VBG pCO2 - 5 mm Hg from the prior studies. In this study, we validated this relationship with simultaneous arterial and central venous blood obtained from 30 patients with four blood sample pairs each in paediatric cardiac surgical ICU patients. Results: There was a strong correlation (R i.e., Pearson's correlation between ABG and aVBG for pH = 0.9544, pCO2 = 0.8738, lactate = 0.9741, HCO3− = 0.9650 and BE = 0.9778. Intraclass correlation co-efficients (ICCs for agreement improved after applying the adjustment rule to venous pH (0.7505 to 0.9454 and pCO2 (0.4354 to 0.741. Bland Altman showed bias (and limits of agreement for pH: 0.008 (−0.04 to + 0.057, pCO2: −3.52 (–9.68 to +2.65, lactate: −0.10 (−0.51 to +0.30, HCO3−: −2.3 (–5.11 to +0.50 and BE: −0.80 (−3.09 to +1.49. Conclusion: ABG and aVBG samples showed strong correlation, acceptable mean differences and improved agreement (high ICC after adjusting the VBG. Hence, it can be promising to use trend values of VBG instead of ABG in conjunction with a correction factor under stable haemodynamic conditions.

  1. Reduction of Switching Surge by Controlled Shunt Reactor Switching of Gas Circuit Breaker

    Science.gov (United States)

    Kohyama, Haruhiko; Ito, Hiroki; Asai, Jun; Hidaka, Mikio; Yonezawa, Takashi

    Controlled switching system (CSS) with a 204kV gas circuit breaker (GCB) demonstrates to reduce an inrush current and to eliminate re-ignitions in shunt reactor switching. Target closing and opening instants for controlled switching are determined by the electrical and mechanical characteristics of GCB. Idle time dependence of the operating time, which gives a sufficient impact on controlling accuracy, is evaluated and successfully compensated by synchronous switching controller (SSC). Field operation of CSS for a year shows an effective suppression of inrush current on closing and prevention of re-ignitions on opening of shunt reactor. The operations also proved that the CSS has a satisfactory performance for electro-magnetic disturbance imposed in practical field.

  2. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  3. FreeSWITCH Cookbook

    CERN Document Server

    Minessale, Anthony

    2012-01-01

    This is a problem-solution approach to take your FreeSWITCH skills to the next level, where everything is explained in a practical way. If you are a system administrator, hobbyist, or someone who uses FreeSWITCH on a regular basis, this book is for you. Whether you are a FreeSWITCH expert or just getting started, this book will take your skills to the next level.

  4. Single Atom Plasmonic Switch

    OpenAIRE

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg

    2015-01-01

    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individ...

  5. Comparison of the activities of binder-added and binder-free Mo/HZSM-5 catalysts in methane dehydroaromatization at 1073 K in periodic CH4-H2 switch operation mode

    Institute of Scientific and Technical Information of China (English)

    Yuebing Xu; Hongtao Ma; Yo Yamamoto; Yoshizo Suzuki; Zhanguo Zhang

    2012-01-01

    Three industry-supplied,well-shaped Mo/HZSM-5 catalysts,two binder-added and one binder-free,were tested for the first time in methane dehydroaromatization to benzene at 1073 K and 10000 mL/(g.h) in periodic CH4-H2 switch operation mode,and their catalytic performances were compared with those of three self-prepared,binder-free powder Mo/HZSM-5 catalysts.XRD,27Al NMR,SEM,BET and NH3-TPD characterizations of all the catalysts show that the zeolites in the two binder-added catalysts are comparable to those in the three binder-free powder catalysts in crystallinity,crystal size,micropore volume and Br(¢)nsted acidity.The test results,on the other hand,show that the catalytic performances of the two binder-added catalysts are worse than those of the four binder-free catalysts on both catalyst mass and zeolite mass bases.Then,TPO and BET measurements of all spent samples were conducted to get a deep insight into the negative effects of binder addition,and the results suggest that the binder additives functioned mainly to enhance the polyaromatization of formed aromatics to coke on their external surfaces and consequently lower the benzene formation activity and selectivity of the catalyst.

  6. Self-Q-switched Cr:LiCAF laser

    OpenAIRE

    Beyatlı, Ersen; Sennaroğlu, Alphan; Demirbaş, Ümit

    2013-01-01

    We report self-Q-switched operation of a Cr:LiCAF laser for the first time to our knowledge. Self-Q-switching (SQS) refers to the generation of a periodic train of Q-switched pulses from a laser cavity containing only the gain medium. Since SQS does not require any additional elements such as saturable absorbers or active modulators, it is far simpler and lower cost in comparison with other Q-switching methods. In the experiments, SQS operation was observed by using an x-shaped, astigmaticall...

  7. Medical treatment in carotid artery intervention

    NARCIS (Netherlands)

    Kolkert, J. L.; Meerwaldt, R.; Lefrandt, Johan; Geelkerken, R. H.; Zeebregts, C. J.

    2011-01-01

    Medical treatment has a pivotal role in the treatment of patients with occlusive carotid artery disease. Large trials have provided the justification for operative treatment besides medical treatment in patients with recent significant carotid artery stenosis two decades ago. Since then, medical the

  8. Resistance switching memory in perovskite oxides

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.B., E-mail: zbyan@nju.edu.cn; Liu, J.-M., E-mail: liujm@nju.edu.cn

    2015-07-15

    The resistance switching behavior has recently attracted great attentions for its application as resistive random access memories (RRAMs) due to a variety of advantages such as simple structure, high-density, high-speed and low-power. As a leading storage media, the transition metal perovskite oxide owns the strong correlation of electrons and the stable crystal structure, which brings out multifunctionality such as ferroelectric, multiferroic, superconductor, and colossal magnetoresistance/electroresistance effect, etc. The existence of rich electronic phases, metal–insulator transition and the nonstoichiometric oxygen in perovskite oxide provides good platforms to insight into the resistive switching mechanisms. In this review, we first introduce the general characteristics of the resistance switching effects, the operation methods and the storage media. Then, the experimental evidences of conductive filaments, the transport and switching mechanisms, and the memory performances and enhancing methods of perovskite oxide based filamentary RRAM cells have been summarized and discussed. Subsequently, the switching mechanisms and the performances of the uniform RRAM cells associating with the carrier trapping/detrapping and the ferroelectric polarization switching have been discussed. Finally, the advices and outlook for further investigating the resistance switching and enhancing the memory performances are given.

  9. 糖尿病足下肢动脉闭塞性病变的外科血管搭桥治疗%Surgical Vascular By-pass Operation of Lower Limb Artery Occlusion in Patients with Diabetic Foot

    Institute of Scientific and Technical Information of China (English)

    黄斌; 赵纪春; 马玉奎; 冉兴无; 袁丁; 杨轶; 吴洲鹏; 卢武胜

    2012-01-01

    Objective To document the effectiveness and patient experience of surgical treatment for diabetic lower limb arterial occlusion. Methods Out of 290 diabetic patients with lower limb arterial occlusion, 69 received by-pass operation because of severe stenosis below the abdominal aorta and severe ulcers in feet from April 2004 to April 2011. We reviewed the experience and outcome of the 69 diabetic patients who underwent surgical operations on lower limb arterial occlusion. Results 100% initial surgical success was achieved. The morbidity (excluding death) was 12. 3% + 4. 1% and 15. 7% ±5. 1% at 1 year and 3 years after operations, respectively. Five (7. 2%) death cases were recorded, which resulted in a survival rate of 94. 2%±2. 8% and 92. 0%±3. 5% at 1 year and 3 years after operations, respectively. About 90. 6%+ 3. 6% and 87. 2%±4. 9% of patients had graft patency 1 year and 3 years after operations, respectively; and 6. 5% + 3. 1% had amputations. Four (5. 8%) patients developed graft thrombosis, in which 2 (2. 9%) had amputations because of recurrence of thrombosis after thrombectomy. Two (2. 9%) patients had amputations because of graft infection accompanied with graft resection operations. One (1.4%) patient received repeated arterialized operation on great saphenous vein because of popliteal artery occlusion, and obtained a good outcome within two years. One (1. 4%) patient developed stomas false aneurysm, but the excision of the false aneurysm resulted in a good outcome in four years. Conclusion Detailed pre-operation assessment, optimal selection of surgical procedure and perioperative management can help improve the outcome of diabetes and decrease amputation rate in patients with diabetic lower limb arterial occlusion.%目的 总结糖尿病足下肢动脉闭塞病变的外科血管搭桥(BPG)治疗经验及体会.方法 回顾性分析2004年4月至2011年4月收治糖尿病足临界性肢体缺血(CLI)的290例患者中69例选择外科BPG方式

  10. Switching overvoltages in offshore wind power grids

    DEFF Research Database (Denmark)

    Arana Aristi, Ivan

    Switching transients in wind turbines, the collection grid, the export system and the external grid in offshore wind farms, during normal or abnormal operation, are the most important phenomena when conducting insulation coordination studies. However, the recommended models and methods from...... electrical systems and the topic of transients is given in Chapter 1. In Chapter 2 it is described how the component and sub-system models are developed and used from an applied point of view, where common and detail models are mentioned. In Chapter 3 results from frequency domain measurement on transformers...... and cables are presented. In Chapter 4 results from time domain measurements and simulations of switching operations in offshore wind power grids are described. Specifically, switching operations on a single wind turbine, the collection grid, the export system and the external grid measured in several real...

  11. Peripheral arterial line (image)

    Science.gov (United States)

    A peripheral arterial line is a small, short plastic catheter placed through the skin into an artery of the arm or leg. The purpose of a peripheral arterial line is to allow continuous monitoring of ...

  12. Parametric scaling study of a magnetically insulated thermionic vacuum switch

    Energy Technology Data Exchange (ETDEWEB)

    Vanderberg, B.H.; Eninger, J.E. [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Industrial Electrotechnology

    1996-02-01

    A parametric scaling study is performed on MINOS (Magnetically INsulated Opening Switch), a novel fast ({approximately}100 ns) high-power opening switch concept based on a magnetically insulated thermionic vacuum diode. Principal scaling parameters are the switch dimensions, voltage, current, applied magnetic field, and switching time. The scaling range of interest covers voltages up to 100 kV and currents of several kA. Fundamental scaling properties are derived from models of space-charge flow and magnetic cutoff. The scaling is completed with empirical results from the experimental MX-1 switch operated in an inductive storage pulsed power generator. Results are presented in diagrams showing voltage, current, power, and efficiency relationships and their limitations. The scaling is illustrated by the design of a megawatt average power opening switch for pulsed power applications. Trade-offs in the engineering of this type of switch are discussed.

  13. Optimal switching using coherent control

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Heuck, Mikkel; Mørk, Jesper

    2013-01-01

    that the switching time, in general, is not limited by the cavity lifetime. Therefore, the total energy required for switching is a more relevant figure of merit than the switching speed, and for a particular two-pulse switching scheme we use calculus of variations to optimize the switching in terms of input energy....

  14. Active plasmonics in WDM traffic switching applications

    DEFF Research Database (Denmark)

    Papaioannou, S.; Kalavrouziotis, D.; Vyrsokinos, K.;

    2012-01-01

    With metal stripes being intrinsic components of plasmonic waveguides, plasmonics provides a "naturally" energy-efficient platform for merging broadband optical links with intelligent electronic processing, instigating a great promise for low-power and small-footprint active functional circuitry....... The first active Dielectric-Loaded Surface Plasmon Polariton (DLSPP) thermo-optic (TO) switches with successful performance in single-channel 10 Gb/s data traffic environments have led the inroad towards bringing low-power active plasmonics in practical traffic applications. In this article, we introduce...... active plasmonics into Wavelength Division Multiplexed (WDM) switching applications, using the smallest TO DLSPP-based Mach-Zehnder interferometric switch reported so far and showing its successful performance in 4310 Gb/s low-power and fast switching operation. The demonstration of the WDM...

  15. Impact of post-operative radiation on coronary arteries in patients of early breast cancer: A pilot dosimetric study from a tertiary cancer care center from India

    Directory of Open Access Journals (Sweden)

    S Roy

    2015-01-01

    Full Text Available Background: The significant impact of postoperative radiotherapy (PORT on cardiac morbidity in patients of early breast cancer (EBC undergoing breast-conserving surgery has been shown in different studies. The present study was conducted to assess the impact of surgery and the side of involvement on radiation dose to left anterior descending artery (LAD and Left circumflex coronary artery (LCx. Materials And Methods: Totally, 58 patients of EBC were randomly chosen for this dosimetric study and planned with tangential field technique without intensity modulation (IM. Heart, LAD, and LCx (n = 55 were contoured. Dose volume histograms were analyzed to determine the Dmax (maximum dose and Dmean (mean dose of LAD and LCx. Student's t-test was used for comparative analysis of the means. Results: The mean Dmax of LAD for left (L EBC was 3.17 Gray (Gy while for right (R EBC it was 0.86 Gy (P = 0.007; 95% C.I, 1.14–3.48. The mean Dmean of LAD for L-EBC and R-EBC were 1.97 Gy and 0.79 Gy, respectively (P = 0.029; 95% C.I, 0.77–1.60. The mean-Dmax of LCx for patients with L-EBC (2.9 Gy; range: 1.2–4.35 Gy was statistically higher than that for R-EBC (1.3 Gy; range: 0.7–3.2 Gy (P = 0.045. The mean-Dmean of LCx for L-EBC (2.1 Gy; range: 0.6–3.6 Gy was also significantly higher than that of L-EBC (0.9 Gy; range: 0.7–2.1 Gy (P = 0.03. There was no significant impact of the pattern of surgery on LAD dose, but significance was noted for LCx dose parameters (P = 0.04 and 0.08 for m-Dmax and m-Dmean of LCx. Conclusion: This pilot dosimetric study confirms the assumption that patients with left-sided EBC are at higher risk of developing long-term cardiac morbidity when treated with PORT due to increased dose to LAD.

  16. Scaling of Superconducting Switches for Extraction of Magnetic Energy

    CERN Document Server

    Ballarino, A

    2010-01-01

    In certain cases it is necessary to extract the energy from a superconducting magnet when it quenches, in order to limit the heat generated by the event and thus prevent irreversible damage. This is usually achieved by opening a contact breaker across a resistor in the circuit feeding the magnet. For the heavy currents used to excite large magnets such switches incorporate sophisticated devices to limit arcing during the operation; besides being quite large and expensive, such switches have a limited lifetime. It is therefore interesting to consider the use of superconducting switches to perform this function, the advantage being that such switches would (i) not require maintenance and (ii) would be housed within the cryogenic environment of the magnet, and thus avoid permanent diversion of the current in and out of that environment to the mechanical switch (which operates at room temperature). However, practical switches for such an application are made up of superconductor in a metal matrix, and it is conve...

  17. Quantum cryptography without switching.

    Science.gov (United States)

    Weedbrook, Christian; Lance, Andrew M; Bowen, Warwick P; Symul, Thomas; Ralph, Timothy C; Lam, Ping Koy

    2004-10-22

    We propose a new coherent state quantum key distribution protocol that eliminates the need to randomly switch between measurement bases. This protocol provides significantly higher secret key rates with increased bandwidths than previous schemes that only make single quadrature measurements. It also offers the further advantage of simplicity compared to all previous protocols which, to date, have relied on switching.

  18. Optical switching device

    NARCIS (Netherlands)

    Broeder, F.J.A. den; Hanzen, R.M.N.; Duine, P.A.; Jungblut, R.M.; Draijer, C.; Roozeboom, F.; Sluis, P. van der

    2000-01-01

    A description is given of an optical switching device (1) comprising a transparent substrate (3), a switching film (5) of a hydride compound of a trivalent transition or rare earth metal having a thickness of 300 nm, and a palladium capping layer (7) having a thickness of 30 nm. The capping layer is

  19. Switch on, switch off: stiction in nanoelectromechanical switches

    KAUST Repository

    Wagner, Till J W

    2013-06-13

    We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the \\'ON\\' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between \\'free\\', \\'pinned\\' and \\'clamped\\' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. © 2013 IOP Publishing Ltd.

  20. Towards the Design of Power Switches Utilizing HTS Material

    CERN Document Server

    March, S A; Beduz, C; Mess, K H; Yang, Y

    2008-01-01

    Conventional superconducting switches for power applications, which operate at liquid helium temperature, generally utilize Nb-Ti superconductor in a cupro-nickel matrix. For superconducting circuits based on High Temperature Superconductors (HTS) that work at higher temperatures, the associated superconducting switches must also be based on HTS. This paper addresses the issues concerning the requirements and the appropriate design of HTS switches, including approaches to fast triggering.

  1. A Low-Cost CMOS Programmable Temperature Switch

    OpenAIRE

    Nanjian Wu; Yunlong Li

    2008-01-01

    A novel uncalibrated CMOS programmable temperature switch with high temperature accuracy is presented. Its threshold temperature Tth can be programmed by adjusting the ratios of width and length of the transistors. The operating principles of the temperature switch circuit is theoretically explained. A floating gate neural MOS circuit is designed to compensate automatically the threshold temperature Tth variation that results form the process tolerance. The switch circuit is implemented in a ...

  2. Switch of the incoming CERN Telecom operator

    CERN Multimedia

    2004-01-01

    The CERN numbering plan (from 022 767 0000 to 022 767 9999) actually owned by Swisscom will be transferred to Sunrise on the 15th of April 2004 between 6:30 to 7:30. During this action, the following disruptions may happen: • External calls to CERN internal fixed phones may be cut at any time for several minutes. • External calls made from CERN mobiles using "333" may be cut at any time for several minutes. At 7:30, once this action is done, the normal status should be recovered.

  3. 400-Mbps, 8 times 8 ATM switch LSI. 400Mbps 8 times 8 ATM switch LSI

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, S.; Tanaka, S.; Noda, M. (Toshiba Corp., Tokyo (Japan))

    1991-08-01

    Was developed at Toshiba, an asynchronous transfer mode (ATM) switch large scale integrated circuit (LSI), which can be used for next-generation telecommunication network systems, such as broadband-integrated services digital network (B-ISDN) For this ATM switch LSI, the common buffer method, which has a good buffer operation efficiency, was adopted as a switch architecture. The flow control and the cell incorporation sequential method were also adopted to improve the cell-loss rate. Furthermore, the BiCMOS (bipolar complimentary MOS) process was applied to the fabrication of this LSI. Consequently, a one-chip 8 input/8 output ATM switch LSI was realized. In addition, the operation speed per channel of this LSI was 400Mbps, and the throughput was 3.2Gbps. 3 refs., 4 figs., 1 tab.

  4. 可编程控制器在进线母联自动切换操作方法上的应用%Application of Programmable Logic Controller in Automatic Switching Operation Between Incoming Cabinet and Bus Tie Breaker Cabinet

    Institute of Scientific and Technical Information of China (English)

    刘永春; 张国忠; 何鸿艺

    2014-01-01

    Aiming at the shortcoming existing in the traditional automatic switching operation between the incoming cabinet and the bus tie breaker cabinet at 6 kV high-voltage substation, this paper proposed to adopt programmable logic controller control (PLC) technology to re-alize new ways of automatically switching, building up the simulation model of substation, expounding manners and contents of the switch-ing operation, enumerating the I/O allocation table controlled by PLC and giving the external wiring diagram and the control ladder diagram. Experimental tests show that the method not only makes all kinds of operation function more perfect, but also makes the operation procedure correct and unique, and it can immediately send light and sound alarm signals for any wrong operation, without causing substantive misop-eration results.%针对6 kV高压变电站进线柜与母联柜传统自动切换操作中存在的不足,提出采用可编程控制器(PLC)控制技术实现自动切换的新方法。建立了变电站的仿真模型,阐述了倒闸操作的方式与内容,列举了PLC控制的I/O分配表,给出了外部接线图以及控制梯形图等。经实验测试,该方法不仅使各种操作功能更加完备,而且操作途径正确、唯一,对错误的操作能立即发出声光报警信号,而不会引起实质性的误操作结果。

  5. Path planning during combustion mode switch

    Science.gov (United States)

    Jiang, Li; Ravi, Nikhil

    2015-12-29

    Systems and methods are provided for transitioning between a first combustion mode and a second combustion mode in an internal combustion engine. A current operating point of the engine is identified and a target operating point for the internal combustion engine in the second combustion mode is also determined. A predefined optimized transition operating point is selected from memory. While operating in the first combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion engine to approach the selected optimized transition operating point. When the engine is operating at the selected optimized transition operating point, the combustion mode is switched from the first combustion mode to the second combustion mode. While operating in the second combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion to approach the target operating point.

  6. Operation Problems and Solutions for Switch Cabinets and Looped Network Cabinets%开关柜、环网柜设备运行问题分析及对策

    Institute of Scientific and Technical Information of China (English)

    杨堃

    2015-01-01

    12~40.5kV开关柜、环网柜设备是电网系统中运行数量最多的一次变电设备,近年来,开关柜、环网柜事故频发,造成了经济损失、人员伤亡等不好的社会影响.通过对在运开关柜、环网柜开展全面排查、治理,发现其事故隐患及固有缺陷主要集中在接线方式、内部电弧释放能力、内部绝缘、发热和防误闭锁等方面,通过制定针对性的对策,开关柜、环网柜事故数量大大减少,电网运行可靠性稳步提升.%12~40.5kV switch cabinets and looped network cabinets of are the largest number of primary substation devices. In recent years,there were many accidents of these devices,which cause negative social influence including economic loss and casualties.Based on comprehensive examination,it is found that the accident potential and inherent defects are mainly concentrated on connection mode,internal arc release ability,internal insulation,overheating,and error-locking preventing.The number of accidents greatly is reduced and the reliability of power system operation is improved significantly through specific countermeasures.

  7. Percutaneous transluminal angioplasty (PTA) of supra-aortic arteries especially the internal carotid artery

    Energy Technology Data Exchange (ETDEWEB)

    Kachel, R.; Basche, S. (Medizinische Akademie, Erfurt (Germany, F.R.). Radiologische Klinik); Heerklotz, I.; Grossmann, K. (Medizinische Akademie, Erfurt (Germany, F.R.). Klinik fuer Innere Medizin); Endler, S. (Medizinische Akademie, Erfurt (Germany, F.R.). Klinik fuer Neurologie und Psychiatrie)

    1991-06-01

    We present our experience with 105 patients in whom percutaneous transluminal angioplasty was performed in 112 stenosed or occluded supra-aortic arteries. Symtoms of cerebrovascular and/or vertebrobasilar insufficiency were present in 104 of the 105 patients. The angioplasty was successful in 35 stenoses of the internal carotid artery, 2 stenoses of the common carotid artery, 1 stenosis of the external carotid artery, 15 stenoses of the vertebral artery, 3 stenoses of the innominate artery and 44 stenoses of the subclavian artery. There were only 4 minor-complications (2 haematomas, 1 transient ischemic attack, 1 small thrombus of the internal carotid artery which was detected by 111-indium platelet scintigraphy and treated by thrombendarterectomy before the appearance of neurological symptoms). All patients were symptom free after angioplasty. During the observations period of 3 to 109 months (average 58 months) there were only two cases with re-stenosis after subclavian angioplasty. The results of more than 700 personal and international published percutaneous transluminal angioplasties of supra-aortic arteries are presented. The results suggest that angioplasty of supra-aortic arteries is an effective method. On strict definition of the indications, the complication rate for angioplasty of the supra-aortic arteries is not likely to be higher than that for operative treatment. (orig.).

  8. Patients undergoing elective coronary artery bypass grafting exhibit poor pre-operative intakes of fruit, vegetables, dietary fibre, fish and vtiman D

    NARCIS (Netherlands)

    Ruiz-Nunez, B.; Hurk, van den Y.A.C.; Vries, de J.H.M.

    2015-01-01

    CHD may ensue from chronic systemic low-grade inflammation. Diet is a modifiable risk factor for both, and its optimisation may reduce post-operative mortality, atrial fibrillation and cognitive decline. In the present study, we investigated the usual dietary intakes of patients undergoing elective

  9. Patients undergoing elective coronary artery bypass grafting exhibit poor pre-operative intakes of fruit, vegetables, dietary fibre, fish and vitamin D

    NARCIS (Netherlands)

    Ruiz-Nunez, B.; van den Hurk, G. H. A. M.; de Vries, J. H. M.; Mariani, M. A.; de Jongste, M. J. L.; Dijck-Brouwer, D. A. J.; Muskiet, F. A. J.

    2015-01-01

    CHD may ensue from chronic systemic low-grade inflammation. Diet is a modifiable risk factor for both, and its optimisation may reduce post-operative mortality, atrial fibrillation and cognitive decline. In the present study, we investigated the usual dietary intakes of patients undergoing elective

  10. Control synthesis of linear distributed parameter switched systems

    Institute of Scientific and Technical Information of China (English)

    Leping Bao; Shumin Fei; Lin Chai

    2015-01-01

    The control synthesis for switched systems is extended to distributed parameter switched systems in Hilbert space. Based on semigroup and operator theory, by means of multiple Lyapunov method incorporated average dwel time approach, sufficient con-ditions are derived in terms of linear operator inequalities frame-work for distributed parameter switched systems. Being applied to one dimensional heat propagation switched systems, these lin-ear operator inequalities are reduced to linear matrix inequalities subsequently. In particular, the state feedback gain matrices and the switching law are designed, and the state decay estimate is explicitly given whose decay coefficient completely depends on the system’s parameter and the boundary condition. Final y, two numerical examples are given to il ustrate the proposed method.

  11. A case of 'task-switching acalculia'.

    Science.gov (United States)

    Domahs, Frank; Benke, Thomas; Delazer, Margarete

    2011-02-01

    In this study we describe a patient (FR) with left frontal lesions due to a cerebrovascular disorder of embolic origin. Beyond a general slowness, FR showed deficits in simple multiplication only when problems were presented in a mixed operations list (multiplication, addition, and subtraction), while no such deficits were observed for the same multiplication problems in blocked presentation. Deficits were restricted to trials directly affected by a switch (increased switch costs), but not to subsequent trials (no increased mixing costs). Thus, we provide the first detailed description of a condition which could be termed 'task-switching acalculia' in a stroke patient. This case highlights the need for mixed operation lists in the diagnosis of acalculia.

  12. JUNOS Enterprise Switching

    CERN Document Server

    Reynolds, Harry

    2009-01-01

    JUNOS Enterprise Switching is the only detailed technical book on Juniper Networks' new Ethernet-switching EX product platform. With this book, you'll learn all about the hardware and ASIC design prowess of the EX platform, as well as the JUNOS Software that powers it. Not only is this extremely practical book a useful, hands-on manual to the EX platform, it also makes an excellent study guide for certification exams in the JNTCP enterprise tracks. The authors have based JUNOS Enterprise Switching on their own Juniper training practices and programs, as well as the configuration, maintenanc

  13. A Metabolic Switch

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    Our muscles are metabolically flexible, i.e., they are capable of `switching' between two types of oxidation: (1) when fasting, a predominantly lipid oxidation with high rates of fatty acid uptake, and (2) when fed, suppression of lipid oxidation in favour of increased glucose uptake, oxidation...... and storage, in response to insulin. One of the many manifestations of obesity and Type 2 diabetes is an insulin resistance of the skeletal muscles, which suppresses this metabolic switch. This talk describes recent development of a low-dimensional system of ODEs that model the metabolic switch, displaying...

  14. Photoconductive switch package

    Science.gov (United States)

    Ca[rasp, George J

    2013-10-22

    A photoconductive switch is formed of a substrate that has a central portion of SiC or other photoconductive material and an outer portion of cvd-diamond or other suitable material surrounding the central portion. Conducting electrodes are formed on opposed sides of the substrate, with the electrodes extending beyond the central portion and the edges of the electrodes lying over the outer portion. Thus any high electric fields produced at the edges of the electrodes lie outside of and do not affect the central portion, which is the active switching element. Light is transmitted through the outer portion to the central portion to actuate the switch.

  15. Electromechanical magnetization switching

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)

    2015-03-14

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

  16. DNA supercoiling enhances cooperativity and efficiency of an epigenetic switch

    DEFF Research Database (Denmark)

    Norregaard, Kamilla; Andersson, Magnus; Sneppen, Kim

    2013-01-01

    Bacteriophage λ stably maintains its dormant prophage state but efficiently enters lytic development in response to DNA damage. The mediator of these processes is the λ repressor protein, CI, and its interactions with λ operator DNA. This λ switch is a model on the basis of which epigenetic switch...

  17. Graphene Q-switched Yb:KYW planar waveguide laser

    NARCIS (Netherlands)

    Kim, Jun Wan; Choi, Sun Young; Aravazhi, Shanmugam; Pollnau, Markus; Griebner, Uwe; Petrov, Valentin; Bae, Sukang; Ahn, Kwang Jun; Yeom, Dong-Il; Rotermund, Fabian

    2015-01-01

    A diode-pumped Yb:KYW planar waveguide laser, single-mode Q-switched by evanescent-field interaction with graphene, is demonstrated for the first time. Few-layer graphene grown by chemical vapor deposition is transferred onto the top of a guiding layer, which initiates stable Q-switched operation in

  18. All-optical devices for ultrafast packet switching

    DEFF Research Database (Denmark)

    Dorren, H.J.S.; HerreraDorren, J.; Raz, O.;

    2007-01-01

    We discuss integrated devices for all-optical packet switching. We focus on monolithically integrated all-optical flip-flops, ultra-fast semiconductor based wavelength converters and explain the operation principles. Finally, a 160 Gb/s all-optical packet switching experiment over 110 km of field...

  19. Carbon Nanotube Switches for Communication and Memory Applications

    Science.gov (United States)

    Kaul, Anupama B.; Epp, Larry; Wong, Eric W.; Kowalczyk, Robert

    2008-01-01

    Lateral CNT Switches: a) dc CNT switches were demonstrated to operate at low voltages, low powers and high speeds. b) RF simulations of switch in series configuration with metallized tube yielded good RF performance 1) Isolation simulated to be approx. 20 dB at 100 GHz. 2) Insertion loss simulated to be < 0.5 dB at 100 GHz. Vertical CNT Switches: a) Thermal CVD was used to mechanically constrain tubes in nanopockets; tubes not self-supporting. b) Demonstrated growth of vertically aligned arrays and single-few MWNTs using dc PECVD with Ni catalyst using optical lithography.

  20. Power Switches Utilizing Superconducting Material for Accelerator Magnets

    CERN Document Server

    March, S A; Yang, Y

    2009-01-01

    Power switches that utilize superconducting material find application in superconducting systems. They can be used for the protection of magnets as a replacement for warm DC breakers, as well as for the replacement of cold diodes. This paper presents a comparison of switches made of various superconducting materials having transport currents of up to 600 A and switching times of the order of milliseconds. The switches operate in the temperature range 4.2-77 K and utilize stainless steel clad YBCO tape and MgB2 tape with a nickel, copper, and iron matrix. Results from simulations and tests are reported.

  1. A new Zero Voltage Switching three-level NPC inverter

    DEFF Research Database (Denmark)

    He, Ning; Chen, Yenan; Xu, Dehong

    2015-01-01

    A novel Zero Voltage Switching (ZVS) three-level NPC inverter topology using a new ZVS Space Vector Modulation (SVM) scheme is proposed. A detailed operation analysis of ZVS three-level NPC inverter is given. The ZVS condition of the proposed ZVS inverter is derived and it can be achieved of all...... switches in the proposed inverter, which include both the main switches and the auxiliary switches. The design of resonant circuits parameters is also provided. Finally the proposed circuit and ZVS SVM scheme are verified by experimental results and demonstrate a superior performance....

  2. Stabilizing Randomly Switched Systems

    CERN Document Server

    Chatterjee, Debasish

    2008-01-01

    This article is concerned with stability analysis and stabilization of randomly switched systems under a class of switching signals. The switching signal is modeled as a jump stochastic (not necessarily Markovian) process independent of the system state; it selects, at each instant of time, the active subsystem from a family of systems. Sufficient conditions for stochastic stability (almost sure, in the mean, and in probability) of the switched system are established when the subsystems do not possess control inputs, and not every subsystem is required to be stable. These conditions are employed to design stabilizing feedback controllers when the subsystems are affine in control. The analysis is carried out with the aid of multiple Lyapunov-like functions, and the analysis results together with universal formulae for feedback stabilization of nonlinear systems constitute our primary tools for control design

  3. Accurate Switched-Voltage voltage averaging circuit

    OpenAIRE

    金光, 一幸; 松本, 寛樹

    2006-01-01

    Abstract ###This paper proposes an accurate Switched-Voltage (SV) voltage averaging circuit. It is presented ###to compensated for NMOS missmatch error at MOS differential type voltage averaging circuit. ###The proposed circuit consists of a voltage averaging and a SV sample/hold (S/H) circuit. It can ###operate using nonoverlapping three phase clocks. Performance of this circuit is verified by PSpice ###simulations.

  4. Photonics in switching

    CERN Document Server

    Midwinter, John E; Kelley, Paul

    1993-01-01

    Photonics in Switching provides a broad, balanced overview of the use of optics or photonics in switching, from materials and devices to system architecture. The chapters, each written by an expert in the field, survey the key technologies, setting them in context and highlighting their benefits and possible applications. This book is a valuable resource for those working in the communications industry, either at the professional or student level, who do not have extensive background knowledge or the underlying physics of the technology.

  5. High Power Switching Transistor

    Science.gov (United States)

    Hower, P. L.; Kao, Y. C.; Carnahan, D. C.

    1983-01-01

    Improved switching transistors handle 400-A peak currents and up to 1,200 V. Using large diameter silicon wafers with twice effective area as D60T, form basis for D7 family of power switching transistors. Package includes npn wafer, emitter preform, and base-contact insert. Applications are: 25to 50-kilowatt high-frequency dc/dc inverters, VSCF converters, and motor controllers for electrical vehicles.

  6. Ten years patency of left internal mammary artery trunk dissection graft after coronary artery bypass procedure

    Institute of Scientific and Technical Information of China (English)

    CHENG Yu-tong; YU Jian-bo; SUN Tao; QUE Bin; WANG Su; LI Zhi-zhong

    2010-01-01

    @@ The left internal mammary artery (LIMA) had become the conduit of choice for myocardial revascularization, since it has been proved that 10 years patency rates of LIMA grafts are more than 90%. 1,2 The arterial graft trunk dissection is a rare event, affecting the procedure effects and related to reoperation.3 According to Kim and coworker's study,4 the arterial graft trunkdelayed dissection manifested by early post-operative angiography only occurred in 6 of 1111 of the off-pump coronary artery bypass grafts. So up to now, the consequence of dissections without severe hemodynamicabnormality is beyond our knowledge.

  7. Photoconductive switch enhancements for use in Blumlein pulse generators

    Science.gov (United States)

    Davanloo, F.; Park, H.; Collins, C. B.; Agee, F. J.

    1999-06-01

    Stacked Blumlein pulse generators developed at the University of Texas at Dallas have produced high-power waveforms with risetimes and repetition rates in the range of 0.2-50 ns and 1-300 Hz, respectively, using a conventional thyratron, spark gap or photoconductive switch. Adaptation of the design has enabled the stacked Blumleins to produce 80 MW, nanosecond pulses with risetimes better than 200 ps into nominally matched loads. The device has a compact line geometry and is commutated by a single GaAs photoconductive switch triggered by a low power laser diode array. Our current investigations involve the switch characteristics that affect the broadening of the current channels in the avalanche, pre-avalanche seedings, the switch lifetime and the durability. This report presents the progress toward improving the GaAs switch operation and lifetime in stacked Blumlein pulsers. Advanced switch treatments including diamond film overcoating are implemented and discussed.

  8. Zinc Oxide Surface Flashover Triggering of Pseudospark Switch

    Institute of Scientific and Technical Information of China (English)

    谢建民; 邱毓昌

    2003-01-01

    Accurate and reliable triggering is one of the most important issues with high powerpseudospark switch, because it not only has an impact on the design of discharge chamber ofswitch, but also has an influence on the dynamic range of operation voltage, repetition frequenciesand lifetime of switch. The unique feature of pseudospark switch is its hollow cathode geometry.The hollow cathode effect produced by the hollow cathode provides the protection of the switchfor the triggering unit from erosion by high discharge plasma. In this paper, a zinc oxide (ZnO)surface flashover triggering is presented. This trigger unit possesses an excellent time delay (80 ns~ 360 ns) and jitter (20 ns ~ 50 ns) at the switch voltage of 30 kV ~ 2 kV. The emitted plasmaelectron density is high enough to trigger switch reliably down to switch voltage of 440 V.

  9. Address switching: Reforming the architecture and traffic of Internet

    Institute of Scientific and Technical Information of China (English)

    LI Xing; BAO CongXiao

    2009-01-01

    The success of the Internet is largely ascribable to the packet-switching scheme, which, however, also presents major challenges. Having identified three missing links in the current Internet architecture based on our long-term experiences of designing and operating large-scale backbones, we put forward a new, but incrementally deployable, network scheme-address switching. The address switching has both the advantages of packet switching and circuit switching; it supplies the missing links in the current Internet architecture and can reform the Internet traffic. Our analysis, protocol design and experiments indicate that the address switching can greatly improve the quality of service (QoS), security and routing scalability of today's Internet. So it can provide flexible, high-performance and "per-service" networking for the scientific research communities. Moreover, it can provide a fairer and more sustainable business model for the commodity Internet.

  10. New topology for soft switching converters: realization of a 2 kW converter which can operate under cumulated radiation doses comprised between 1 and 10 mega-rads; Nouvelle topologie de convertisseur a commutation douce: realisation d'un convertisseur 2 kW fonctionnant pour des doses de rayonnement cumulees comprises entre 1 et 10 Mega-rads

    Energy Technology Data Exchange (ETDEWEB)

    Marceau, M. [CEA/Saclay, Dept. d' Electronique et d' Instrumentation Nucleaire (DEIN), 91 - Gif-sur-Yvette (France); Huillet, H.; Ploquin, D. [Gaia Converter, 33 - Merignac (France)

    1998-11-01

    This paper presents a new topology of a patented power converter. This topology applies to DC-DC converters with soft switching operation. The power density reached is of about 4000 W/liter and the efficiency is greater than 90%. This converter, devoted to nuclear applications, has been dimensioned to be able to operate under cumulated radiation doses greater than 1 Mega rads. A functioning principle scheme and a brief description of the topology is reported in this short paper. (J.S.)

  11. The new technique of using the epigastric arteries in renal transplantation with multiple renal arteries

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Amirzargar

    2013-01-01

    Full Text Available The most common anatomic variant seen in the donor kidneys for renal transplantation is multiple renal arteries (MRA, which can cause an increased risk of complications. We describe the long-term outcomes of 16 years of experience in 76 kidney transplantations with MRAs. In a new reconstruction technique, we remove arterial clamps after anastomosing the donor to the recipient′s main renal vessels, which cause backflow from accessory arteries to prevent thrombosis. By this technique, we reduce the ischemic times as well as the operating times. Both in live or cadaver donor kidneys, lower polar arteries were anastomosed to the inferior epigastric artery and upper polar arteries were anastomosed to the superior epigastric arteries. Injection of Papaverine and ablation of sympathic nerves of these arteries dilate and prevent them from post-operative spasm. Follow-up DTPA renal scan in all patients showed good perfusion and function of the transplanted kidney, except two cases of polar arterial thrombosis. Mean creatinine levels during at least two years of follow-up remained acceptable. Patient and graft survival were excellent. No cases of ATN, hypertension, rejection and urologic complications were found. In conclusion, this technique can be safely and successfully utilized for renal transplantation with kidneys having MRAs, and may be associated with a lower complication rate and better graft function compared with the existing techniques.

  12. Low inductance gas switching.

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.

    2007-10-01

    The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and

  13. Soft switching buck-boost converter for photovoltaic power generation; Taiyoko hatsuden no tame no soft switching shokoatsu converter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H. [Kyungnam University (Korea, Republic of)

    1996-10-27

    A soft switching method with small switching loss was proposed for the purpose of increasing the efficiency of a DC-DC boost converter which converted a DC current generated by solar cells to a variable DC current. Existing current converters are supplemented by using a snubber circuit around the switch so as to protect the switch by a hard switching action. However, with an increase of the output current, snubber loss is increased, reducing the efficiency. In order to solve this problem, the partial resonant switch method was applied to the converter; with this method of partially forming a resonant circuit only at the time of turning on/off of the switch, the switching loss was reduced through the soft switching, thereby making the proposed converter operate with high efficiency. Moreover, the resonant element of the partial resonant circuit using a snubber condenser, the energy accumulated in the condenser was regenerated on the power supply side without loss of snubber. With the regenerated energy, the proposed converter was provided with a smaller ratio of switching to use than the conventional converter. 4 refs., 7 figs., 1 tab.

  14. Duplex ultrasound for identifying renal artery stenosis

    DEFF Research Database (Denmark)

    Zachrisson, Karin; Herlitz, Hans; Lönn, Lars

    2017-01-01

    Background Renal artery duplex ultrasound (RADUS) is an established method for diagnosis of renal artery stenosis (RAS), but there is no consensus regarding optimal RADUS criteria. Purpose To define optimal cutoff values for RADUS parameters when screening for RAS using intra-arterial trans...... as PGM ≥15 mmHg and was found in 43 of the 76 arteries. RADUS parameters included renal artery peak systolic velocity (PSV) and the renal-aortic ratio (RAR) of flow velocities. Receiver operating characteristic curves (ROCs) and Youden's index were used to calculate optimal RADUS criteria for RAS...... The RAR ≥2.6 is a more sensitive criterion than traditional RADUS criteria when screening patients with clinical suspicion of RAS....

  15. Jet pump assisted arterial heat pipe

    Science.gov (United States)

    Bienert, W. B.; Ducao, A. S.; Trimmer, D. S.

    1978-01-01

    This paper discusses the concept of an arterial heat pipe with a capillary driven jet pump. The jet pump generates a suction which pumps vapor and noncondensible gas from the artery. The suction also forces liquid into the artery and maintains it in a primed condition. A theoretical model was developed which predicts the existence of two stable ranges. Up to a certain tilt the artery will prime by itself once a heat load is applied to the heat pipe. At higher tilts, the jet pump can maintain the artery in a primed condition but self-priming is not possible. A prototype heat pipe was tested which self-primed up to a tilt of 1.9 cm, with a heat load of 500 watts. The heat pipe continued to prime reliably when operated as a VCHP, i.e., after a large amount of noncondensible gas was introduced.

  16. Improved Design Techniques for Switched-Capacitor Ladder Filters.

    Science.gov (United States)

    Hsu, Teng-Hsien

    Using the new developments of MOS technology, switched-capacitor filters which consist of operational amplifiers, capacitors and switches in monolithic form, were widely investigated and put into practical forms. The switched-capacitor ladder filters have derived from doubly-terminated reactance two-ports. The main part of this dissertation is aimed at improving the efficiency and eliminating some shortcomings of the bilinear design technique. Two novel input stages which incorporate the necessary sample-and-hold function into the bilinear ladder filters are presented. The circuits are insensitive to parasitic capacitances. Some techniques to reduce the number of operational amplifier for bilinear switched-capacitor ladder filters are given. The number of top-plate parasitic-sensitive capacitors is less than in any of the existing design techniques. The clock feedthrough effects of pseudo-N-path switched-capacitor filter using lowpass filters as path filters are eliminated by the improved technique with doubling the number of operational amplifiers. Two-phase pseudo -N-path switched-capacitor filters can be obtained by tripling the number of operational amplifiers. The design technique for extending bilinear lowpass switched-capacitor ladder filters from odd orders to even orders is presented. One of the factors limiting the speed of bilinear switched-capacitor ladder filters is the delay-free loops. The techniques for breaking delay-free loops of low-order switched -capacitor filters are introduced. Digital ladder filters can be obtained through those switched-capacitor filters without delay-free loops. Numerical examples are given to compare the following digital filters: general cascade realization, wave digital filter, the digital filters derived from switched-capacitor filters - cascade and ladder. An improved high speed switched-capacitor linear interpolator, and nonlinear interpolators are described. The circuits are completely parasitic-insensitive. Two

  17. Valley blockade quantum switching in Silicon nanostructures.

    Science.gov (United States)

    Prati, Enrico

    2011-10-01

    In analogy to the Coulomb and the Pauli spin blockade, based on the electrostatic repulsion and the Pauli exclusion principle respectively, the concept of valley blockade in Silicon nanostructures is explored. The valley parity operator is defined. Valley blockade is determined by the parity conservation of valley composition eigenvectors in quantum transport. A Silicon quantum changeover switch based on a triple of donor quantum dots capable to separate electrons having opposite valley parity by virtue of the valley parity conservation is proposed. The quantum changeover switch represents a novel kind of hybrid quantum based classical logic device.

  18. Using MEMS Capacitive Switches in Tunable RF Amplifiers

    Directory of Open Access Journals (Sweden)

    Danson John

    2006-01-01

    Full Text Available A MEMS capacitive switch suitable for use in tunable RF amplifiers is described. A MEMS switch is designed, fabricated, and characterized with physical and RF measurements for inclusion in simulations. Using the MEMS switch models, a dual-band low-noise amplifier (LNA operating at GHz and GHz, and a tunable power amplifier (PA at GHz are simulated in m CMOS. MEMS switches allow the LNA to operate with 11 dB of isolation between the two bands while maintaining dB of gain and sub- dB noise figure. MEMS switches are used to implement a variable matching network that allows the PA to realize up to 37% PAE improvement at low input powers.

  19. Ultrafast polarization optical switch constructed from one-dimensional photonic crystal and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; LI Qing; GAO DingShan

    2009-01-01

    All-optical switch with the ultrafast optical switching rate is a key device in the next generation optical network. In this article, we propose a polarization switch with ps switching time, which is constructed from one-dimensional resonant photonic crystal (1D RPC). The model of switch operating at 1.5 μm is established based on the optical stark effect (OSE). We calculate the performance indices of the switch and the influences of errors of periods and refractive index on the performance characteristics.

  20. Circuit with a Switch for Charging a Battery in a Battery Capacitor Circuit

    Science.gov (United States)

    Stuart, Thomas A. (Inventor); Ashtiani, Cyrus N. (Inventor)

    2008-01-01

    A circuit for charging a battery combined with a capacitor includes a power supply adapted to be connected to the capacitor, and the battery. The circuit includes an electronic switch connected to the power supply. The electronic switch is responsive to switch between a conducting state to allow current and a non-conducting state to prevent current flow. The circuit includes a control device connected to the switch and is operable to generate a control signal to continuously switch the electronic switch between the conducting and non-conducting states to charge the battery.

  1. Polarization switching in vertical-cavity surface emitting lasers observed at constant active region temperature

    Science.gov (United States)

    Martín-Regalado, J.; Chilla, J. L. A.; Rocca, J. J.; Brusenbach, P.

    1997-06-01

    Polarization switching in gain-guided, vertical-cavity, surface-emitting lasers was studied as a function of the active region temperature. We show that polarization switching occurs even when the active region temperature is kept constant during fast pulse low duty cycle operation. This temperature independent polarization switching phenomenon is explained in terms of a recently developed model.

  2. On stability of switched linear systems with perturbed switching paths

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper addresses the stability issue of switched linear systems with perturbed switching paths. First,by introducing thenotions of child-path and parent-path, we are able to define the distance between two switching paths by means of their switching matrices chains. Next, we present the nice properties of the defined distance. Then, a stability criterion is presented for a class of switched linear systems with perturbed switching paths. Finally, an illustrative example is presented to verify the effectiveness of the approach.

  3. A Novel Single-Switch Single-Stage Electronic Ballast

    Institute of Scientific and Technical Information of China (English)

    Lu-Hua Zhu; Xing-Bi Chen; Hong-Sheng Zhong

    2009-01-01

    A single-stage single-switch high- frequency electronic ballast topology is presented. The circuit topology is the integration of a buck power- factor-correction (PFC) converter and a class E resonant inverter with only one active power switch. The buck converter is operated in discontinuous conduction mode and at a fixed switching frequency, and constant duty cycle to achieve high power factor and it can be controlled easily. Detailed analysis of the operation and characteristics of the circuit is provided. Simulation results satisfy present standard require- ments.

  4. Switching speed limitations of high power IGBT modules

    DEFF Research Database (Denmark)

    Incau, Bogdan Ioan; Trintis, Ionut; Munk-Nielsen, Stig

    2015-01-01

    In this paper the switching speed limits of high power IGBT modules are investigated. The limitation of turn-on and turn-off switching speeds of the IGBTs are experimentally detected in a pulse tester. Different dc-bus stray inductances are considered, as well as the worst case scenario...... for the blocking dc-link voltage. Switching losses are analyzed upon a considerable variation of resistor value from turn-on gate driver side. Short circuit operations are investigated along with safe operating area for entire module to validate electrical capabilities under extreme conditions....

  5. Vacuum interrupters and thyratrons as opening switches

    Science.gov (United States)

    Honig, E. M.

    High power opening switches for inductive storage for large scale energy storage applications are described. The triggered vacuum interrupter and the magnetically quenched thyratrons are discussed. By electrically retriggering the discharge in the vacuum interrupter between pulses, the dependence on mechanical motion is eliminated. This should enable repetition rate operation at 10 to 15 kHz while still maintaining the vacuum interrupter's proven interrupting performance of tens of kiloamps at tens of kilovolts. The magnetically quenched thyratron uses a cross magnetic field to raise the switch impedance by decreasing the electron mobility and driving the discharge into an arc chute wall where it is quenched. Attempts to understand the basic mechanisms involved and to increase the switch, ratings, and particularly the conduction time, are discussed.

  6. Magnetic switch for reactor control rod. [LMFBR

    Science.gov (United States)

    Germer, J.H.

    1982-09-30

    A magnetic reed switch assembly is described for activating an electromagnetic grapple utilized to hold a control rod in position above a reactor core. In normal operation the magnetic field of a permanent magnet is short-circuited by a magnetic shunt, diverting the magnetic field away from the reed switch. The magnetic shunt is made of a material having a Curie-point at the desired release temperature. Above that temperature the material loses its ferromagnetic properties, and the magnetic path is diverted to the reed switch which closes and short-circuits the control circuit for the control rod electro-magnetic grapple which allows the control rod to drop into the reactor core for controlling the reactivity of the core.

  7. GIS隔离开关操作过程中管壳空间暂态电磁辐射计算%Computation of Transient Electromagnetic Field Emission from Enclosure During GIS Disconnector Switching Operations

    Institute of Scientific and Technical Information of China (English)

    干喆渊; 赵军; 张建功; 谢鹏康; 陈恒林

    2016-01-01

    With the fast development of power system, intelligent equipment is increasingly applied in substations.Disconnector operation in gas insulated switchgear (GIS) always produces electromagnetic field emissions.Therefore, it has very important reference significance to analyze the electromagnetic field distribution for the electromagnetic compatibility design of the electronic equipment installed around the GIS enclosures.We established the circuit models of grounding enclosure and electromagnetic emission, and calculated the electromagnetic field caused by the enclosure current during switching operation.The results show that the electromagnetic field waveform follows the enclosure current waveform.Near the enclosure, the electromagnetic field decays fast, far from the enclosure, electric field decays linearly while magnetic field decays exponentially.With the number increasing of grounding points, the amplitude of TEV decreases obviously, and the electromagnetic field are smaller far from the bushing.The electromagnetic field near grounding enclosure is measured, and the measured results basically coincide with the calculation results.%随着电力系统的不断发展,越来越多的电子设备引入到变电站中,而气体绝缘开关设备(gas insulated switchgear, GIS)中的隔离开关操作往往作会造成空间暂态电磁辐射,分析隔离开关操作过程中GIS管壳周围空间电磁场分布对安装在管壳周围的电子设备的电磁兼容设计有着非常重要的参考意义.建立了GIS管壳的电路和电磁辐射模型,计算得到了GIS隔离开关操作过程中管壳接地电流引起的空间暂态电磁场.结果表明:管壳周围电磁场时域波形跟随管壳电流变化;管壳附近的空间电磁场随着与管壳之间距离增加而剧烈衰减,在离管壳较远的位置,电场呈线性衰减,磁场呈指数衰减;随着接地点个数增加,暂态对地过电压的幅值显著降低,且离套管位置较远处电磁场

  8. [Grafting of carotid arteries].

    Science.gov (United States)

    Belov, Iu V; Stepanenko, A B; Gens, A P; Bazylev, V V; Seleznev, M N; Savichev, D D

    2005-01-01

    Over 5-years, 167 reconstructive surgeries for stenosis of internal carotid arteries (ICA) were performed in 124 patients. Mean age of the patients was 63.5 years. One hundred and twenty-nine carotid endarterectomies (CEAE) in 86 patients and 38 reconstructive operations of ICA in 38 patients were performed. There were no lethal outcomes in short- and long-term postoperative period. In short-term period after prosthesis of ICA restenosis was revealed in 3% patients, after eversion CEAE in 3% patients the embolism was seen, after standard CEAE restenosis were diagnosed in 8% patients and thrombosis -- in 3%. In long-term period after grafting of ICA the strokes were seen in 3%, stenosis -- in 6% patients, after eversion endarterectomy -- in 0 and 3% patients, and after standard CEAE -- in 3 and 24% patients, respectively. It is concluded that grafting of ICA is adequate surgical method of reconstruction and stroke prevention in specific variants of carotid atherosclerosis.

  9. Mesenteric artery ischemia

    Science.gov (United States)

    ... medlineplus.gov/ency/article/001156.htm Mesenteric artery ischemia To use the sharing features on this page, please enable JavaScript. Mesenteric artery ischemia occurs when there is a narrowing or blockage ...

  10. Microfabricated triggered vacuum switch

    Science.gov (United States)

    Roesler, Alexander W.; Schare, Joshua M.; Bunch, Kyle

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  11. Stable Amplification and High Current Drop Bistable Switching in Supercritical GaAs Tills

    DEFF Research Database (Denmark)

    Izadpanah, S.H; Jeppsson, B; Jeppesen, Palle

    1974-01-01

    Bistable switching with current drops of 40% and switching times of 100 ps are obtained in pulsed operation of 10¿m supercritically doped n+ nn+ GaAs Transferred Electron Devices (TEDs). When CW-operated the same devices exhibit a 5-17 GHz bandwidth for the stable negative resistance.......Bistable switching with current drops of 40% and switching times of 100 ps are obtained in pulsed operation of 10¿m supercritically doped n+ nn+ GaAs Transferred Electron Devices (TEDs). When CW-operated the same devices exhibit a 5-17 GHz bandwidth for the stable negative resistance....

  12. Magneto-optical switch with amorphous silicon waveguides on magneto-optical garnet

    Science.gov (United States)

    Ishida, Eiichi; Miura, Kengo; Shoji, Yuya; Mizumoto, Tetsuya; Nishiyama, Nobuhiko; Arai, Shigehisa

    2016-08-01

    We fabricated a magneto-optical (MO) switch with a hydrogenated amorphous silicon waveguide on an MO garnet. The switch is composed of a 2 × 2 Mach-Zehnder interferometer (MZI). The switch state is controlled by an MO phase shift through a magnetic field generated by a current flowing in an electrode located on the MZI. The switching operation was successfully demonstrated with an extinction ratio of 11.7 dB at a wavelength of 1550 nm.

  13. ? stability of wind turbine switching control

    Science.gov (United States)

    Palejiya, Dushyant; Shaltout, Mohamed; Yan, Zeyu; Chen, Dongmei

    2015-01-01

    In order to maximise the wind energy capture, wind turbines are operated at variable speeds. Depending on the wind speed, a turbine switches between two operating modes: a low wind speed mode and a high wind speed mode. During the low wind speed mode, the control objective is to maximise wind energy capture by controlling both the blade pitch angle and the electrical generator torque. During the high wind speed mode, the control goal is to maintain the rated power generation by only adjusting the blade pitch angle. This paper establishes the stability criteria for the switching operation of wind turbines using ? gain under the nonlinear control framework. Also, the performance of the wind turbine system is analysed by using the step response, a well-known measure for second-order linear systems.

  14. Upper limb arterial thromboembolism

    DEFF Research Database (Denmark)

    Andersen, L V; Lip, Gregory Y.H.; Lindholt, J S;

    2013-01-01

    The aim of this review is to focus on risk factors, risk-modifying drugs and prognosis for upper limb arterial thromboembolism, and the relationship between upper limb arterial thromboembolism and atrial fibrillation (AF).......The aim of this review is to focus on risk factors, risk-modifying drugs and prognosis for upper limb arterial thromboembolism, and the relationship between upper limb arterial thromboembolism and atrial fibrillation (AF)....

  15. Beyond the switch

    DEFF Research Database (Denmark)

    Aliakseyeu, Dzmitry; Meerbeek, Bernt; Mason, Jon

    2014-01-01

    and established lighting network, and with the advent of the LED, new types of lighting output are now possible. However, the current approach for controlling such systems is to simply replace the light switch with a somewhat more sophisticated smartphone-based remote control. The focus of this workshop...... is to explore new ways of interacting with light where lighting can not only be switched on or off, but is an intelligent system embedded in the environment capable of creating a variety of effects. The connectivity between multiple systems and other ecosystems, for example when transitioning from your home...

  16. Optical Packet Switching Demostrator

    DEFF Research Database (Denmark)

    Mortensen, Brian Bach; Berger, Michael Stübert

    2002-01-01

    In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set-up and the m......In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set...

  17. Anterior Tibial Artery Pseudoaneurysm: Case Report

    Directory of Open Access Journals (Sweden)

    Funda Tor

    2012-06-01

    Full Text Available The aneurysmsatic changes of the infrapopliteal arteries are rarely seen. They are pseudoaneurysms rather than true aneursyms. The most important cause of them is trauma. There is not a standart treatment for infrapopliteal aneursyms. In this study, we have evaluated a case operated for anterior tibial artery pseudoaneurysm developed after penetrant trauma and diagnosed two weeks later. [Cukurova Med J 2012; 37(3.000: 172-175

  18. A New Zero Voltage Switching Buck-Boost Type DC-DC Converter

    Directory of Open Access Journals (Sweden)

    Majid Delshad

    2010-03-01

    Full Text Available In this paper, a new zero voltage switching isolated buck-boost DC-DC converter with active clamp circuit is proposed. The active clamp circuit in this converter not only absorbs voltage spikes across the main switch but also provides soft switching conditions for all switches. All switches are PWM controlled which simplifies the control implementation. One of the main advantages of this converter is the that it operating can operate at high power levels while soft switching conditions exist in both buck and boost modes of converter operation. Since this converter can operate over a wide input voltage range, it can be employed in power factor correction. The experimental results obtained from a 150W prototype circuit operating at 100KHz are presented to confirm the integrity of the proposed circuit.

  19. Research of an electromagnetically actuated spark gap switch.

    Science.gov (United States)

    Zhang, Tianyang; Chen, Dongqun; Liu, Jinliang; Wang, Yuwei; Qiu, Yongfeng

    2013-11-01

    As an important part of pulsed power systems, high-voltage and high-current triggered spark gap switch and its trigger system are expected to achieve a compact structure. In this paper, a high-voltage, high-current, and compact electromagnetically actuated spark gap switch is put forward, and it can be applied as a part of an intense electron-beam accelerator (IEBA). A 24 V DC power supply is used to trigger the switch. The characteristics of the switch were measured for N2 when the gas pressure is 0.10-0.30 MPa. The experimental results showed that the voltage/pressure (V/p) curve of the switch was linear relationship. The operating ranges of the switch were 21%-96%, 21%-95%, 21%-95%, 19%-95%, 17%-95%, and 16%-96% of the switch's self-breakdown voltage when the gas pressures were 0.10, 0.14, 0.18, 0.22, 0.26, and 0.30 MPa, respectively. The switch and its trigger system worked steadily and reliably with a peak voltage of 30 kV, a peak current of 60 kA in the IEBA when the pressure of N2 in the switch was 0.30 MPa.

  20. DESIGN OF AN ARRAYED WAVEGUIDE GRATINGS BASED OPTICAL PACKET SWITCH

    Directory of Open Access Journals (Sweden)

    VAIBHAV SHUKLA

    2016-12-01

    Full Text Available Optical packet switching is considered as the future of data transfer technologyin combination with middle-aged electronics. The biggest challenge encountered in optical packet switching is the lack of optical buffers for storing the contending packets. Therefore, for the contention resolution of packets, a temporary storage in terms of fiber delay lines is used. This task is accomplished by an optical packet switch. In this paper, a design modification in the AWGR (Arrayed Waveguide Grating Router is presented for improving the switch performance. The power budget analysis of the switch is also presented to estimate the sufficient power level of the switch. The obtained results clearly reveal that the architecture presented in this paper can be operated in micro-watts in comparison to the earlier optical switch which operates in milli watts regime. Finally, simulation results are presented to obtain packet loss probability and average delay. Even at the higher load of 0.6, the switch presented in this paper provides a very low loss probability (10^6 and delay remain within 2 slots.

  1. A Switched Capacitor Harmonic Compensation Part for Switching Supplies

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    A new approach based on switched capacitor network to harmonic compensation for switching supplies is presented in the paper,The basic principle is discussed.SPICE simulation is applied to analyze the behaviour of the switched capacitor harmonic compensation part.

  2. Microelectrical Mechanical Systems Switch for Designing Multi-Band Antenna

    Directory of Open Access Journals (Sweden)

    A. H.M.Z. Alam

    2009-01-01

    Full Text Available Problem statement: In this study Microelectrical Mechanical System (MEMS switches were proposed to design a reconfigurable/multi-band antenna to replaced PIN diode switches or semiconductor switches due to lower insertion losses, good isolation, much lower intermodulation distortion, and lower power consumption. The antenna is able to operate at very high frequencies. Approach: A reconfigurable antenna that is capable to operate at several frequencies was proposed by introducing two adjacent patches along with main radiating patch and two MEMS switches. Parametric analysis of the size of the wing patches was done for finding optimum size. A comparative study was done for Alumina, SiN, GaAs and Teflon as MEMS bridge materials for finding better results in terms of return loss and number of bands. The design was performed by using 3D electromagnetic simulator HFSS considering ideal MEMS switches. Results: It was found that SiN as MEMS bridge material makes the antenna to operate at 16.76, 23.56 and 27.7 GHz in the “OFF” states and operate at 20.9 and 21.91 GHz in the “ON” states of MEMS switches. Conclusion/Recommendations: MEMS cantilever beam material played an important role for providing antenna to operate at multi-band frequencies. The proposed multiband/reconfigurable antenna can be implemented with easy fabrication process steps by the Sandwich method of fabrication.

  3. Photonic MEMS switch applications

    Science.gov (United States)

    Husain, Anis

    2001-07-01

    As carriers and service providers continue their quest for profitable network solutions, they have shifted their focus from raw bandwidth to rapid provisioning, delivery and management of revenue generating services. Inherently transparent to data rate the transmission wavelength and data format, MEMS add scalability, reliability, low power and compact size providing flexible solutions to the management and/or fiber channels in long haul, metro, and access networks. MEMS based photonic switches have gone from the lab to commercial availability and are now currently in carrier trials and volume production. 2D MEMS switches offer low up-front deployment costs while remaining scalable to large arrays. They allow for transparent, native protocol transmission. 2D switches enable rapid service turn-up and management for many existing and emerging revenue rich services such as storage connectivity, optical Ethernet, wavelength leasing and optical VPN. As the network services evolve, the larger 3D MEMS switches, which provide greater scalability and flexibility, will become economically viable to serve the ever-increasing needs.

  4. Safe LPV Controller Switching

    DEFF Research Database (Denmark)

    Trangbæk, K

    2010-01-01

    Before switching to a new controller it is crucial to assure that the new closed loop will be stable. In this paper it is demonstrated how stability can be checked with limited measurement data available from the current closed loop. The paper extends an existing method to linear parameter varying...

  5. Switching Between Multivariable Controllers

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob; Abrahamsen, Rune

    2004-01-01

    it is possible to smoothly switch between multivariable controllers with guaranteed closed-loop stability. This includes also the case where one or more controllers are unstable. The concept for smooth online changes of multivariable controllers based on the YJBK architecture can also handle the start up...

  6. DIGITAL TELEPHONE SWITCH: SOFTWARE

    Directory of Open Access Journals (Sweden)

    J. G. Viveros Talavera

    2003-07-01

    Full Text Available This paper describes the design of the program of control for a Digital Phone Switch (PBAX with a maximumcapacity of one hundred and twenty-eight lines (extensions and trunks. The control program was designedusing object-oriented programming and concurrent programming techniques.

  7. The Octopus switch

    NARCIS (Netherlands)

    Havinga, Paul Johannes Mattheus

    2000-01-01

    This chapter1 discusses the interconnection architecture of the Mobile Digital Companion. The approach to build a low-power handheld multimedia computer presented here is to have autonomous, reconfigurable modules such as network, video and audio devices, interconnected by a switch rather than by a

  8. [Upper extremity arterial diseases].

    Science.gov (United States)

    Becker, F

    2007-02-01

    Compared to lower limb arterial diseases, upper limb arterial diseases look rare, heterogeneous with various etiologies and a rather vague clinical picture, but with a negligible risk of amputation. Almost all types of arterial diseases can be present in the upper limb, but the anatomical and hemodynamic conditions particular to the upper limb often confuse the issue. Thus, atherosclerosis affects mainly the subclavian artery in its proximal segment where the potential of collateral pathway is high making the symptomatic forms not very frequent whereas the prevalence of subclavian artery stenosis or occlusion is relatively high. The clinical examination and the etiologies are discussed according to the clinical, anatomical and hemodynamic context.

  9. Measurement of Blood Flow in an Intracranial Artery Bypass From the Internal Maxillary Artery by Intraoperative Duplex Sonography.

    Science.gov (United States)

    Yu, Zaitao; Shi, Xiang'en; Brohi, Shams Raza; Qian, Hai; Liu, Fangjun; Yang, Yang

    2017-02-01

    This study explored the hemodynamic characteristics of a subcranial-intracranial bypass from the internal maxillary artery by measuring blood flow on intraoperative duplex sonography. The hemodynamic parameters of the internal maxillary artery (n = 20), radial artery (n = 20), internal maxillary artery-middle cerebral artery bypass (n = 42), and internal maxillary artery-posterior cerebral artery bypass (n = 9) were measured by intraoperative duplex sonography. There was no significant difference in the internal diameters of the internal maxillary and radial arteries (mean ± SD, 2.51 ± 0.34 versus 2.56 ± 0.22 mm; P = .648). The mean radial artery graft length for subcranial-intracranial bypasses was 88.5 ± 12.78 mm (95% confidence interval [CI], 80.8-90.2 mm). Internal maxillary artery-middle cerebral artery bypasses required a shorter radial artery graft than internal maxillary artery-posterior cerebral artery bypasses (77.8 ± 2.47 versus 104.8 ± 4.77 mm; P = .001). The mean flow volumes were 85.3 ± 18.5 mL/min (95% CI, 76.6-93.9 mL/min) for the internal maxillary artery, 72.6 ± 26.4 mL/min (95% CI, 64.3-80.9 mL/min) for internal maxillary artery-middle cerebral artery bypasses, and 45.4 ± 6.7 mL/min (95% CI, 40.7-50.0 mL/min) for internal maxillary artery-posterior cerebral artery bypasses. All grafts were opened after the success of the salvage procedures had been established, and the early patency rates (1 month after the operation) were 95% for internal maxillary artery-middle cerebral artery bypasses and 100% the internal maxillary artery-posterior cerebral artery bypasses. Measurement of blood flow by intraoperative sonography can be helpful in decision making and predicting graft patency and success after neurosurgical bypass procedures.

  10. Closing photoconductive semiconductor switches

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, G.M.; Zutavern, F.J.; Hjalmarson, H.P.; O' Malley, M.W.

    1989-01-01

    One of the most important limitations of Photoconductive Semiconductor Switches (PCSS) for pulsed power applications is the high laser powers required to activate the switches. In this paper, we discuss recent developments on two different aspects of GaAs PCSS that result in reductions in laser power by a factor of nearly 1000. The advantages of using GaAs over Si are many. First of all, the resistivity of GaAs can be orders of magnitude higher than that of the highest resistivity Si material, thus allowing GaAs switches to withstand dc voltages without thermal runaway. Secondly, GaAs has a higher carrier mobility than Si and, thus, is more efficient (per carrier). Finally, GaAs switches can have naturally fast (ns) opening times at room temperature and low fields, microsecond opening times at liquid nitrogen temperature of 77 K, or, on demand, closing and opening at high fields and room temperature by a mechanism called lock-on (see Ref. 1). By contrast, Si switches typically opening times of milliseconds. The amount of laser light required to trigger GaAs for lock-on, or at 77 K, is about three orders of magnitude lower than at room temperature. In this paper we describe the study of lock-on in GaAs and InP, as well as switching of GaAs at 77 K. We shall show that when GaAs is switched at 77 K, the carrier lifetime is about three orders of magnitude longer than it is at room temperature. We shall explain the change in lifetime in terms of the change in electron capture cross section of the deep levels in GaAs (these are defect or impurity levels in the band gap). In the second section, we describe the lock-on effect, now seen in GaAs and InP, and at fields as high as 70 kV/cm. We show how lock-on can be tailored by changing the GaAs temperature or by neutron bombardment. In the third section, we discuss possible lock-on mechanisms. 5 refs., 5 figs.

  11. Emergency off-pump coronary artery surgery

    Institute of Scientific and Technical Information of China (English)

    Shahzad G Raja; Zulfiqar Haider; Haider Zaman

    2004-01-01

    Background Off-pump coronary artery bypass grafting is fast-becoming a procedure of choice for elective revascularization in high-risk patients with multi-vessel coronary artery disease. However, the role of off-pump coronary artery bypass grafting for patients with acute coronary syndromes requiring emergency revascularization still requires validation. We present our experience to show the feasibility of off-pump coronary artery surgery as an emergency revascularization technique. Methods From April 2001 to September 2003, emergency (operation within 24 hours after hospitalization) coronary artery bypass grafting without cardiopulmonary bypass (CPB) was performed in 66 patients with a mean age of (66.9±5.4) years (range 49-72 years). They presented acute coronary syndromes with 38 patients on platelet glycoprotein Ⅱb/Ⅲa receptor antagonists. All patients underwent off-pump coronary artery bypass surgery via sternotomy with the intention of complete coronary revascularization.Results An average of 2.9 grafts per patient were performed and the posterior descending artery and marginal branches of the circumflex artery were grafted in 83.3% of the patients. There were 4 events of intraoperative cardiac instability, precipitated by occlusion of right coronary artery or positioning of a cardiomegaly heart, leading to immediate conversion to CPB. The mortality rate was 3% (2/66). Two patients suffered postoperative stroke while three needed hemofiltration for acute renal failure. Post surgery elective coronary angiography (n=46) showed no significant stenosis.Conclusion Emergency off-pump coronary artery surgery with complete revascularization is feasible in patients with acute coronary syndrome with low morbidity and mortality and excellent early results.

  12. Heat-transfer thermal switch

    Science.gov (United States)

    Friedell, M. V.; Anderson, A. J.

    1974-01-01

    Thermal switch maintains temperature of planetary lander, within definite range, by transferring heat. Switch produces relatively large stroke and force, uses minimum electrical power, is lightweight, is vapor pressure actuated, and withstands sterilization temperatures without damage.

  13. Control synthesis of switched systems

    CERN Document Server

    Zhao, Xudong; Niu, Ben; Wu, Tingting

    2017-01-01

    This book offers its readers a detailed overview of the synthesis of switched systems, with a focus on switching stabilization and intelligent control. The problems investigated are not only previously unsolved theoretically but also of practical importance in many applications: voltage conversion, naval piloting and navigation and robotics, for example. The book considers general switched-system models and provides more efficient design methods to bring together theory and application more closely than was possible using classical methods. It also discusses several different classes of switched systems. For general switched linear systems and switched nonlinear systems comprising unstable subsystems, it introduces novel ideas such as invariant subspace theory and the time-scheduled Lyapunov function method of designing switching signals to stabilize the underlying systems. For some typical switched nonlinear systems affected by various complex dynamics, the book proposes novel design approaches based on inte...

  14. Transradial artery coronary angioplasty.

    Science.gov (United States)

    Kiemeneij, F; Laarman, G J; de Melker, E

    1995-01-01

    This study explored the feasibility and safety of percutaneous coronary balloon angioplasty (PTCA) with miniaturized PTCA equipment via the radial artery. Coronary angioplasty (PTCA) via the femoral or brachial arteries may be associated with rare vascular complications such as bleeding and damage to the artery and adjacent structures. It was postulated that PTCA via the radial artery with miniaturized angioplasty equipment is feasible and that no major puncture site-related complications occur because hemostasis is obtained easily and because no major structures are near the radial artery. With double blood supply to the hand, radial artery occlusion is well tolerated. In 100 patients with collateral blood supply to the right hand, PTCA was attempted with 6F guiding catheters and rapid-exchange balloon catheters for exertional angina (87 patients) or nonexertional angina (13 patients). Angioplasty was attempted in 122 lesions (type A n = 67 [55%], Type B n = 37 [30%], and type C n = 18 [15%]). Pre- and post-PTCA computerized quantitative coronary analysis was performed. Radial artery function and structure were assessed clinically and with Doppler and two-dimensional ultrasound on the day of discharge. Coronary catheterization via the radial artery was successful in 94 patients (94%). The 6 remaining patients had successful PTCA via the femoral artery (n = 5) or the brachial artery (n = 1). Procedural success (120 of 122 lesions) was achieved in 92 patients (98%) via the radial artery and in 98 patients of the total study population.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Off-pump coronary artery bypass grafting in patients with mirror-imaging dextrocardia.

    Science.gov (United States)

    Yuan, Xin; Sun, Hansong; Wang, Xianqiang

    2015-08-01

    Dextrocardia requires alterations in techniques during coronary artery bypass graft (CABG) surgery. We report two cases undergoing off-pump coronary artery bypass graft (OPCAB) surgery and discuss techniques for the operative management of these patients.

  16. ANALYSIS OF 312 CASES OF REPEAT CORONARY ARTERY BYPASS GRAFTING

    Institute of Scientific and Technical Information of China (English)

    陈长志; 陆佩中

    2003-01-01

    Objective To evaluate repeat coronary artery bypass grafting (CABG) in 312 patients.Methods The data of 312 patients (average age 65±9 years) who had CABG operation in Hartford hospital were collected and analyzed. The mean duration follow up after the first CABG was 11.8±4.5 years. A total of 1069 bypass grafts were performed. Among them, 386 were arterial grafts such as internal mammary artery, radial artery and gastroepiploic artery; 682 were venous grafts and 1 Gore-Tex graft. Results The operative mortality was 4. 5%. Fifteen patients (4. 8%) had peri-operative myocardial infarction and 46 patients (15%) had low cardiac output syndrome. Intra-aortic balloon pump (IABP) was used in 131 patients before, during and after operation. One hundred and nineteen patients weaned off IABP and recovered. ConclusionAlthough the difficulties and risk factors were increased, the results of redo CABG were still good.

  17. Persistent-current switch for pancake coils of rare earth-barium-copper-oxide high-temperature superconductor: Design and test results of a double-pancake coil operated in liquid nitrogen (77-65 K) and in solid nitrogen (60-57 K)

    Science.gov (United States)

    Qu, Timing; Michael, Philip C.; Voccio, John; Bascuñán, Juan; Hahn, Seungyong; Iwasa, Yukikazu

    2016-08-01

    We present design and test results of a superconducting persistent current switch (PCS) for pancake coils of rare-earth-barium-copper-oxide, REBCO, high-temperature superconductor (HTS). Here, a REBCO double-pancake (DP) coil, 152-mm ID, 168-mm OD, 12-mm high, was wound with a no-insulation technique. We converted a ˜10-cm long section in the outermost layer of each pancake to a PCS. The DP coil was operated in liquid nitrogen (77-65 K) and in solid nitrogen (60-57 K). Over the operating temperature ranges of this experiment, the normal-state PCS enabled the DP coil to be energized; thereupon, the PCS resumed the superconducting state and the DP coil field decayed with a time constant of 100 h, which would have been nearly infinite, i.e., persistent-mode operation, were the joint across the coil terminals superconducting.

  18. Acute occlusion of the left subclavian artery with artery dissection

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Subclavian steal syndrome is cerebral or brain stem ischemia resulting from diversion of blood flow from the basilar artery to the subclavian artery, which is caused by occlusive disease of either the subclavian artery or the innominate artery before they branch off at the vertebral artery. In the patients with subclavian steal syndrome the subclavian artery is fed by retrograde flow from the vertebral artery via the carotids and the circle of Willis.

  19. Unity power factor switching regulator

    Science.gov (United States)

    Rippel, Wally E. (Inventor)

    1983-01-01

    A single or multiphase boost chopper regulator operating with unity power factor, for use such as to charge a battery is comprised of a power section for converting single or multiphase line energy into recharge energy including a rectifier (10), one inductor (L.sub.1) and one chopper (Q.sub.1) for each chopper phase for presenting a load (battery) with a current output, and duty cycle control means (16) for each chopper to control the average inductor current over each period of the chopper, and a sensing and control section including means (20) for sensing at least one load parameter, means (22) for producing a current command signal as a function of said parameter, means (26) for producing a feedback signal as a function of said current command signal and the average rectifier voltage output over each period of the chopper, means (28) for sensing current through said inductor, means (18) for comparing said feedback signal with said sensed current to produce, in response to a difference, a control signal applied to the duty cycle control means, whereby the average inductor current is proportionate to the average rectifier voltage output over each period of the chopper, and instantaneous line current is thereby maintained proportionate to the instantaneous line voltage, thus achieving a unity power factor. The boost chopper is comprised of a plurality of converters connected in parallel and operated in staggered phase. For optimal harmonic suppression, the duty cycles of the switching converters are evenly spaced, and by negative coupling between pairs 180.degree. out-of-phase, peak currents through the switches can be reduced while reducing the inductor size and mass.

  20. Abacus switch: a new scalable multicast ATM switch

    Science.gov (United States)

    Chao, H. Jonathan; Park, Jin-Soo; Choe, Byeong-Seog

    1995-10-01

    This paper describes a new architecture for a scalable multicast ATM switch from a few tens to thousands of input ports. The switch, called Abacus switch, has a nonblocking memoryless switch fabric followed by small switch modules at the output ports; the switch has input and output buffers. Cell replication, cell routing, output contention resolution, and cell addressing are all performed distributedly in the Abacus switch so that it can be scaled up to thousnads input and output ports. A novel algorithm has been proposed to resolve output port contention while achieving input and output ports. A novel algorithm has been proposed to reolve output port contention while achieving input buffers sharing, fairness among the input ports, and multicast call splitting. The channel grouping concept is also adopted in the switch to reduce the hardware complexity and improve the switch's throughput. The Abacus switch has a regular structure and thus has the advantages of: 1) easy expansion, 2) relaxed synchronization for data and clock signals, and 3) building the switch fabric using existing CMOS technology.

  1. Novel, Four-Switch, Z-Source Three-Phase Inverter

    DEFF Research Database (Denmark)

    Antal, Robert; Muntean, Nicolae; Boldea, Ion

    2010-01-01

    ) value as in six switch standard three-phase inverter. The article presents the derivation of the equations describing the operation of the converter based on space vector analysis, validation through digital simulations in PSIM and preliminary experimental results on a laboratory setup with a dsPIC30F......, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the proposed four-switch z-source inverter, by self boosting, brings the output voltage at same (or higher...

  2. Advances in high voltage power switching with GTOs

    Energy Technology Data Exchange (ETDEWEB)

    Podlesak, T.F. (US Army Electronic Technology and Devices Lab., Fort Monmouth, NJ (US)); McMurray, J.A. (Vitronics, Eatontown, NJ (US)); Carter, J.L.

    1990-12-01

    The control of high voltage at high power, particularly opening switches, has been difficult in the past. Using gate turnoff thyristors (GTOs) arranged in series enables large currents to be switched at high voltage. A high voltage opening switch has been successfully demonstrated in our laboratory. This switch uses GTOs in series and successfully operates at voltages higher than the rated voltage of the individual devices. It is believed that this is the first time this has been successfully demonstrated, in that GTOs have been operated in series before, but always in a manner as to not exceed the voltage capability of the individual devices. In short, the devices have not worked together, sharing the voltage, but one device has been operated using several backup devices. Of particular interest is how well the individual devices share the voltage applied to them. Equal voltage sharing between devices is absolutely essential, in order to not exceed the voltage rating of any of the devices in the series chain. This is accomplished at high (microsecond) switching speeds. Thus, the system is useful for high frequency applications as well as high power, making for a flexible circuit system element. This paper reports on this demonstration system that is rated at 5 KV and uses 1 KV devices. A larger 24 KV system is under design and will use 4.5 KV devices. In order to design the 24 KV switch, the safe operating area of the large devices must be known thoroughly.

  3. Bilateral accessory thoracodorsal artery.

    Science.gov (United States)

    Natsis, Konstantinos; Totlis, Trifon; Tsikaras, Prokopios; Skandalakis, Panagiotis

    2006-09-01

    The subscapular artery arises from the third part of the axillary artery and gives off the circumflex scapular and the thoracodorsal arteries. Although anatomical variations of the axillary artery are very common, the existence of a unilateral accessory thoracodorsal artery has been described in the literature only once. There are no reports of bilateral accessory thoracodorsal artery, in the literature. In the present study, a bilateral accessory thoracodorsal artery, originating on either side of the third part of the axillary artery, is described in a 68-year-old female cadaver. All the other branches of the axillary artery had a typical origin, course, distribution and termination. This extremely rare anatomical variation apart from the anatomical importance also has clinical significance for surgeons in this area. Especially, during the dissection or mobilization of the latissimus dorsi that is partly used for coverage problems in many regions of the body and also in dynamic cardiomyoplasty, any iatrogenic injury of this accessory artery may result in ischemia and functional loss of the graft.

  4. Evaluation of combined valve operation and coronary artery bypass grafting%瓣膜手术同期行冠脉搭桥手术35例体会

    Institute of Scientific and Technical Information of China (English)

    杨崛圣; 项海燕; 徐建军; 陈向来; 龙翔; 唐燕华

    2015-01-01

    Objective To summarize the experience of combined valve operation and coronary artery bypass grafting. Methods A total of 35 patients hospitalized in our department have been investigated from May 2009 to June 2014 B ,including 28 cases male,7 cases female,age range of 45-68 years (62±4.67 years),heart function classification (NYHA):grade II 17 cases,gradeⅢ11 cases,gradeⅢ-Ⅳ 7 cases. All cases have been diagnosed by coronary angiography. Cardiac operations have been performed under moderate hypothermic cardiopulmonary bypass. Vascular anastomosis and/or the bridge internal mammary anastomosis have been operated first,then revalvuloplasty or replacement has been performed;vein grafts in the proximal anastomosis have been achieved after aortic opening. Within the group of patients,6 cases underwent mechanical mitral valve replacement,6 cases under-went bioprosthetic mitral valve replacement;7 cases underwent mitral valve replacement plus three tricuspid valve plasty;8 cases underwent mitral bioprosthetic replacement plus three tricuspid valve plasty;1 cases underwent mechanical aortic valve replace-ment,1 cases underwent biological valve replacement;two tip 2 cases underwent mitral valvuloplasty;1case underwent two tricus-pid plus three tricuspid annuloplasty;3 cases underwent mitral valve replacement plus aortic valve replacement plus three tricus-pid annuloplasty. Bridge vessel number is listed as follows:1 of 28 cases;2 of 4 cases;3 of 1 case;4 of 2 cases. Results There was no operative death but one case of perioperative death among the 35 patients. cases of all patients had no operation death ,Total heart ICU monitoring time in all patients was 2-17 days (3.28 ±2.83 days). Hospitalization Total hospitalization time was 11-34days(19.4±4.61 days). Conclusion Coronary artery bypass grafting is effective,safe and reliable operation of valve.%目的:总结瓣膜手术同期行冠状动脉旁路移植术的体会。方法2009年5月-2014年6

  5. Neurotransmitter Switching? No Surprise.

    Science.gov (United States)

    Spitzer, Nicholas C

    2015-06-03

    Among the many forms of brain plasticity, changes in synaptic strength and changes in synapse number are particularly prominent. However, evidence for neurotransmitter respecification or switching has been accumulating steadily, both in the developing nervous system and in the adult brain, with observations of transmitter addition, loss, or replacement of one transmitter with another. Natural stimuli can drive these changes in transmitter identity, with matching changes in postsynaptic transmitter receptors. Strikingly, they often convert the synapse from excitatory to inhibitory or vice versa, providing a basis for changes in behavior in those cases in which it has been examined. Progress has been made in identifying the factors that induce transmitter switching and in understanding the molecular mechanisms by which it is achieved. There are many intriguing questions to be addressed.

  6. Python Switch Statement

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available The Python programming language does not have a built in switch/case control structure as found in many other high level programming languages. It is thought by some that this is a deficiency in the language, and the control structure should be added. This paper demonstrates that not only is the control structure not needed, but that the methods available in Python are more expressive than built in case statements in other high level languages.

  7. Operation and Maintenance of Antenna Switch Based on the Radio Transmitter%基于广播发射机天线交换开关运行维护探析

    Institute of Scientific and Technical Information of China (English)

    王文杰

    2015-01-01

    The high power short wave radio transmitting usually have a number of transmitter and radio coverage task for several directions respectively. Due to the time of each frequency band, broadcast transmitter, the transmitting antenna Angle and service in a different direction, to make full use of the transmitter and the transmitting antenna resources, ensuring uninterrupted broadcast; In order to make the transmitter output automatically by the transmission feeder, flexible switching to a different transmitting antenna, the antenna switching control switch is the first choice of implementing these.%大功率短波广播发射台一般都有多部发射机,分别担负好几个方向的广播覆盖任务。由于每部发射机工作频段、播音时间、发射天线角度和服务方向不同,为了充分利用发射机和发射天线资源,保障不间断的播出,为了使发射机输出通过传输馈线自动、灵活切换到不同的发射天线上,天线交换控制开关是实现这些功能的首选设备。本文简要介绍了天线交换控制开关工作原理,并以 DF-100A 型短波发射机TKP-Ⅲ天线交换开关控制柜和 TK5天线交换开关为例,针对实际工作中运行维护所出现的典型故障以及故障处理进行了分析论述。

  8. Gas adsorption/absorption heat switch, phase 1

    Science.gov (United States)

    Chan, C. K.

    1987-01-01

    The service life and/or reliability of far-infrared sensors on surveillance satellites is presently limited by the cryocooler. The life and/or reliability, however, can be extended by using redundant cryocoolers. To reduce parasitic heat leak, each stage of the inactive redundant cryocooler must be thermally isolated from the optical system, while each stage of the active cryocooler must be thermally connected to the system. The thermal break or the thermal contact can be controlled by heat switches. Among different physical mechanisms for heat switching, mechanically activated heat switches tend to have low reliability and, furthermore, require a large contact force. Magnetoresistive heat switches are, except at very low temperatures, of very low efficiency. Heat switches operated by the heat pipe principle usually require a long response time. A sealed gas gap heat switch operated by an adsorption pump has no mechanical motion and should provide the reliability and long lifetime required in long-term space missions. Another potential application of a heat switch is the thermal isolation of the optical plane during decontamination.

  9. "Platform switching": Serendipity

    Directory of Open Access Journals (Sweden)

    N Kalavathy

    2014-01-01

    Full Text Available Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

  10. "Platform switching": serendipity.

    Science.gov (United States)

    Kalavathy, N; Sridevi, J; Gehlot, Roshni; Kumar, Santosh

    2014-01-01

    Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

  11. [Pediatric case of congenital coronary artery fistula; surgical result and late changes in coronary artery aneurysm].

    Science.gov (United States)

    Sugawara, Masaaki; Oguma, Fumiaki; Hirahara, Hiroyuki

    2014-07-01

    Congenital coronary artery fistula is an uncommon heart anomaly involving the coronary arteries. We report here a case of a 4-year-old boy who had a coronary fistula from the right coronary artery to the right ventricle, with a coronary aneurysm. He was asymptomatic, but the calculated ratio of pulmonary blood flow to systemic blood flow was shown to be high [pulmonary flow (Qp)/systemic flow(Qs)=1.78]. The coronary angiography showed that the right coronary artery was dilated beginning at the ostium and had an aneurysm at the acute marginal portion. A large spherical aneurysm approximately 20 mm in diameter was found to have been connected with coronary fistula opening into the right ventricle. Surgical repair by closure of the fistula under direct vision, partial resection and suture closure of the aneurysm was performed. Plication of the proximal portion of the right coronary artery was not performed, and the diffusely dilated artery was left untouched. After this operation, he recovered well under anticoagulant treatment with warfarin and aspirin. Postoperative angiography was performed 17 months after the surgery to evaluate morphological changes in the coronary artery. The angiography confirmed the closure of the fistula and the regression of coronary artery dilatation.

  12. Unusual origin of the artery of Adamkiewicz from the fourth lumbar artery

    Energy Technology Data Exchange (ETDEWEB)

    Lo, D.; Vallee, J.N.; Spelle, L.; Cormier, E.; Chiras, J. [Service de Neuroradiologie Charcot, Hopital de la Salpetriere, Paris (France); Saillant, G. [Service de Chirurgie Orthopedique et de Traumatologie, Hopital de la Salpetriere, Paris (France); Rancurel, G. [Service D' urgences Cerebro-Vasculaires, Hopital de la Salpetriere, Paris (France)

    2002-02-01

    The main arterial supply of the dorso-lumbar spinal cord is usually derived from a single anterior radiculo-medullary artery called the artery of Adamkiewicz and referred to as having a middle or low location. In some cases, the artery origin is higher, and a vessel which arises in the lower part of the region supplements the supply of the anterior spinal artery. In the literature, those arteries have been described as arising from L3 upwards, and have never been previously described angiographically, to our knowledge, below this level, although Suh and Alexander and Gililan have mentioned this eventuality. Of the 4,000 spinal cord angiographies performed in our institution, we report three cases in which the fourth lumbar artery flows into the anterior spinal artery of the conus medullaris. This anatomical variant may explain the sometimes devastating post-operative neurological complications from a spinal cord infarction on surgery of the lumbar spine or the abdominal aorta below L3. (orig.)

  13. Lingual and facial arteries arising from the external carotid artery in a common trunk.

    Science.gov (United States)

    Troupis, Theodore G; Dimitroulis, Dimitrios; Paraschos, Alexandros; Michalinos, Adamantios; Protogerou, Vassilis; Vlasis, Konstantinos; Troupis, George; Skandalakis, Panayiotis

    2011-02-01

    The present study describes analytically a rare case in which lingual and facial arteries arise together from an external carotid artery in a common trunk. Thirty anatomic dissections were performed on 15 cadavers in the macroscopic laboratory in the Department of Anatomy of the Medical School of National and Kapodistrian University of Athens. One common trunk from which originated lingual and facial arteries was found. The frequency of this morphology is measured at 6 per cent. The length of the common trunk is measured at 7.3 mm between its origin and its diversion at the facial artery and lingual artery, its diameter at 2.8 mm, its distance from carotid bifurcation at 7.9 mm, and from the superior thyroid artery at 3.3 mm. At the left side of the neck region, facial and lingual arteries arose separately. The anatomic variations of the branching pattern of the external carotid artery and the micrometric values of the vessels are especially important as a result of the numerous operations performed in the neck region that implicate various specialties such as general surgery, head and neck surgery, plastic surgery, and maxillofacial surgery.

  14. A New Hard Switching Bidirectional Converter With High Power Density

    Directory of Open Access Journals (Sweden)

    Bahador Fani

    2010-01-01

    Full Text Available In this paper, a new isolated dc-dc bidirectional converter is proposed. This converter consists of two transformers (flyback and forward and only one switch in primary side and one switch in secondary side of transformers. In this converter energy transfers to the output in both on and off switch states so power density of this converter is high This converter controlled by PWM signal. Also this converter operates over a wide input voltage range. Theoretical analysis is presented and computer simulation and experimental results verify the converter analysis.

  15. Celiac Artery Compression Syndrome

    Directory of Open Access Journals (Sweden)

    Mohammed Muqeetadnan

    2013-01-01

    Full Text Available Celiac artery compression syndrome is a rare disorder characterized by episodic abdominal pain and weight loss. It is the result of external compression of celiac artery by the median arcuate ligament. We present a case of celiac artery compression syndrome in a 57-year-old male with severe postprandial abdominal pain and 30-pound weight loss. The patient eventually responded well to surgical division of the median arcuate ligament by laparoscopy.

  16. Popliteal artery entrapment syndrome.

    LENUS (Irish Health Repository)

    O'Leary, D P

    2010-01-01

    Popliteal artery entrapment syndrome is a rare abnormality of the anatomical relationship between the popliteal artery and adjacent muscles or fibrous bands in the popliteal fossa. The following is a case report of a 19 year old female, in whom popliteal artery entrapment syndrome was diagnosed, and successfully treated surgically. A review of literature is also presented and provides details on how PAES is classified, diagnosed both clinically and radiologically, and treated surgically.

  17. Nanoarchitectonic atomic switch networks for unconventional computing

    Science.gov (United States)

    Demis, Eleanor C.; Aguilera, Renato; Scharnhorst, Kelsey; Aono, Masakazu; Stieg, Adam Z.; Gimzewski, James K.

    2016-11-01

    Developments in computing hardware are constrained by the operating principles of complementary metal oxide semiconductor (CMOS) technology, fabrication limits of nanometer scaled features, and difficulties in effective utilization of high density interconnects. This set of obstacles has promulgated a search for alternative, energy efficient approaches to computing inspired by natural systems including the mammalian brain. Atomic switch network (ASN) devices are a unique platform specifically developed to overcome these current barriers to realize adaptive neuromorphic technology. ASNs are composed of a massively interconnected network of atomic switches with a density of ∼109 units/cm2 and are structurally reminiscent of the neocortex of the brain. ASNs possess both the intrinsic capabilities of individual memristive switches, such as memory capacity and multi-state switching, and the characteristics of large-scale complex systems, such as power-law dynamics and non-linear transformations of input signals. Here we describe the successful nanoarchitectonic fabrication of next-generation ASN devices using combined top-down and bottom-up processing and experimentally demonstrate their utility as reservoir computing hardware. Leveraging their intrinsic dynamics and transformative input/output (I/O) behavior enabled waveform regression of periodic signals in the absence of embedded algorithms, further supporting the potential utility of ASN technology as a platform for unconventional approaches to computing.

  18. Observation of Antiphase State in a Self-Q-switched Nd,Cr:YAG Laser

    Institute of Scientific and Technical Information of China (English)

    SHI Yu-Xian; LI Qi-Nan; DU Shi-Feng; ZHANG Dong-Xiang; ZHANG Zhi-Guo; FENG Bao-Hua; ZHANG Shi-Wen

    2009-01-01

    We experimentally investigate the antiphase dynamics phenomenon in a self-Q-switched Nd, Cr: YA G laser oper-ating at 946 nm. Due to the effect of spatial hole burning, the Q-switched pulses sequences of one, two and three modes at different pump power are observed. The experimental results show that the pulse sequences display classic antiphase dynamics.

  19. Simulation of New Switched Capacitance Power Converter for Srm

    Directory of Open Access Journals (Sweden)

    S. M. Mohamed Saleem

    2014-06-01

    Full Text Available In this paper, design and simulation of switched capacitance power converter are proposed for 6/4 switched reluctance motor (SRM drive. The operating principle and design consideration of the proposed converter is explained. The proposed converter performance is better in reduction of torque ripple and constant speed can be achieved quickly with reduced power loss when compared with asymmetric converter. The proposed system is simulated by using MATLAB Simulink and their results are clearly presented.

  20. Locally-Actuated Graphene-Based Nano-Electro-Mechanical Switch

    Directory of Open Access Journals (Sweden)

    Jian Sun

    2016-07-01

    Full Text Available The graphene nano-electro-mechanical switches are promising components due to their outstanding switching performance. However, most of the reported devices suffered from a large actuation voltages, hindering them from the integration in the conventional complementary metal-oxide-semiconductor (CMOS circuit. In this work, we demonstrated the graphene nano-electro-mechanical switches with the local actuation electrode via conventional nanofabrication techniques. Both cantilever-type and double-clamped beam switches were fabricated. These devices exhibited the sharp switching, reversible operation cycles, high on/off ratio, and a low actuation voltage of below 5 V, which were compatible with the CMOS circuit requirements.

  1. Feedback Solution to Optimal Switching Problems With Switching Cost.

    Science.gov (United States)

    Heydari, Ali

    2016-10-01

    The problem of optimal switching between nonlinear autonomous subsystems is investigated in this paper where the objective is not only bringing the states to close to the desired point, but also adjusting the switching pattern, in the sense of penalizing switching occurrences and assigning different preferences to utilization of different modes. The mode sequence is unspecified and a switching cost term is used in the cost function for penalizing each switching. It is shown that once a switching cost is incorporated, the optimal cost-to-go function depends on the subsystem which was active at the previous time step. Afterward, an approximate dynamic programming-based method is developed, which provides an approximation of the optimal solution to the problem in a feedback form and for different initial conditions. Finally, the performance of the method is analyzed through numerical examples.

  2. Contribution to the electrothermal simulation in power electronics. Development of a simulation methodology applied to switching circuits under variable operating conditions; Contribution a la simulation electrothermique en electronique de puissance. Developpement d`une methode de simulation pour circuits de commutation soumis a des commandes variables

    Energy Technology Data Exchange (ETDEWEB)

    Vales, P.

    1997-03-19

    In modern hybrid or monolithic integrated power circuits, electrothermal effects can no longer be ignored. A methodology is proposed in order to simulate electrothermal effects in power circuits, with a significant reduction of the computation time while taking into account electrical and thermal time constants which are usually widely different. A supervising program, written in Fortran, uses system call sequences and manages an interactive dialog between a fast thermal simulator and a general electrical simulator. This explicit coupling process between two specific simulators requires a multi-task operating system. The developed software allows for the prediction of the electrothermal power dissipation drift in the active areas of components, and the prediction of thermally-induced coupling effects between adjacent components. An application to the study of hard switching circuits working under variable operating conditions is presented

  3. Minimally invasive cardiac surgery-coronary artery bypass graft.

    Science.gov (United States)

    Lemma, Massimo; Atanasiou, Thanos; Contino, Monica

    2013-01-01

    Coronary artery bypass graft (CABG) is among the most common operations performed in the world. Different surgical strategies can be used with different invasiveness. This paper describes a recent development of the technique that merges the advantages resulting from both the adoption of an 'off-pump no-touch aorta operation' and a 'complete arterial revascularization through a left minithoracotomy' in a single procedure. This operation is currently known with the acronym MICS (minimally invasive cardiac surgery)-CABG (minimally invasive cardiac surgery). It is an off-pump operation performed through a minithoracotomy in the fourth or fifth left intercostal space across the midclavicular line. The left internal thoracic artery (LITA) is harvested under direct vision using a special rib-retractor with multiple interchangeable thoracotomy blades, including blades to use with lift systems for proximal artery harvesting, while the right radial artery (RA) is harvested endoscopically. A Y-connection is made between the two arteries. The LITA is used to bypass the left anterior descending coronary artery, while the right RA is used on the obtuse marginal branches and/or the posterior descending coronary artery. A special coronary stabilizer and a heart positioner with a shaft for remote thoracic insertion are needed.

  4. Anomalous origin of right coronary artery from pulmonary artery

    Directory of Open Access Journals (Sweden)

    Rajat Gupta

    2012-01-01

    Full Text Available Anomalous origin of coronary artery from the pulmonary artery is a rare anomaly that most frequently involves the left coronary artery and very rarely the right coronary artery. These lesions can be missed on echocardiography unless carefully looked for. We describe a case of isolated anomalous origin of right coronary artery from pulmonary artery diagnosed on echocardiography and confirmed by computed tomography (CT angiography.

  5. A Study of MPLS Hybrid Switch Based on ATM Switch

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    MPLS is the most successful integrating model of IP over ATM. The paper discusses some problems and their possible solutions when MPLS is supported by ATM switch. How to design the hardware, software and network management systems of such a switch device that has only one switching platform and one NMS but two sets of control planes at the same time, ATM and MPLS, is studied in details. The application of such a hybrid switch is presented in the last part of the paper.

  6. Mammary artery harvesting using the Da Vinci Si robotic system

    Directory of Open Access Journals (Sweden)

    Leonardo Secchin Canale

    2014-03-01

    Full Text Available Internal mammary artery harvesting is an essential part of any coronary artery bypass operation. Totally endoscopic coronary artery bypass graft surgery has become reality in many centers as a safe and effective alternative to conventional surgery in selected patients. Internal mammary artery harvesting is the initial part of the procedure and should be performed equally safely if one wants to achieve excellence in patency rates for the bypass. We here describe the technique for mammary harvesting with the Da Vinci Si robotic system.

  7. Composite Thermal Switch

    Science.gov (United States)

    McDonald, Robert; Brawn, Shelly; Harrison, Katherine; O'Toole, Shannon; Moeller, Michael

    2011-01-01

    Lithium primary and lithium ion secondary batteries provide high specific energy and energy density. The use of these batteries also helps to reduce launch weight. Both primary and secondary cells can be packaged as high-rate cells, which can present a threat to crew and equipment in the event of external or internal short circuits. Overheating of the cell interior from high current flows induced by short circuits can result in exothermic reactions in lithium primary cells and fully charged lithium ion secondary cells. Venting of the cell case, ejection of cell components, and fire have been reported in both types of cells, resulting from abuse, cell imperfections, or faulty electronic control design. A switch has been developed that consists of a thin layer of composite material made from nanoscale particles of nickel and Teflon that conducts electrons at room temperature and switches to an insulator at an elevated temperature, thus interrupting current flow to prevent thermal runaway caused by internal short circuits. The material is placed within the cell, as a thin layer incorporated within the anode and/or the cathode, to control excess currents from metal-to-metal or metal-to-carbon shorts that might result from cell crush or a manufacturing defect. The safety of high-rate cells is thus improved, preventing serious injury to personnel and sensitive equipment located near the battery. The use of recently available nanoscale particles of nickel and Teflon permits an improved, homogeneous material with the potential to be fine-tuned to a unique switch temperature, sufficiently below the onset of a catastrophic chemical reaction. The smaller particles also permit the formation of a thinner control film layer (switch (CTS(TradeMark)) coating can be incorporated in either the anode or cathode or both. The coating can be applied in a variety of different processes that permits incorporation in the cell and electrode manufacturing processes. The CTS responds quickly

  8. Comparison of nuring of thoracoscopic and median sternal incision cononary artery bypass graft operation%胸腔镜与正中开胸冠状动脉搭桥术后的护理比较

    Institute of Scientific and Technical Information of China (English)

    汤红莲; 苏冰莲; 徐建婷

    2010-01-01

    Objective To compare nuring of thoracoscopic and median sternal incision cononary artery bypass graft (CABG) .To investigate the peculiarity of nuring after thoracoscopic CABG.Methods From April 2005 to November 2008 , 57 cases of thoracoscopic CABG and 65 cases of median sternal incision CABG were performed in our hospital.The nuring after both type of operations, including monitoring of hemodynamics, ward of circulatory and respiratory system, using of vasoactive drugs, drainage blood volume and pain were analyzed and campared.Results The patients underwent thoracoscopic CABG had more stable circulatory and respiratory system, less using of vasoactive drugs, earlier time of extubation, eating, movement and recovery, a little more pulmonary complications than the patients underwent median sternal incision CABG.Conclusions The nuring of thoracoscopic CABG is easier, less amount of work and more efficient than those of median sternal incision CABG.The patients of thoracoscopic CABG have less trauma and pain, recover more quickly and cound leave ICU earilier.%目的 比较胸腔镜冠状动脉搭桥与正中开胸冠状动脉搭桥的术后护理方法,探讨术后护理的特点和措施.方法 分析胸腔镜下冠状动脉搭桥患者57例与常规正中开胸冠状动脉搭桥缺损65例患者术后血流动力学监测、循环与呼吸系统的监护、血管活药物的应用、引流血量及术后疼痛护理等方面情况.结果 胸腔镜下冠状动脉搭桥较正中开胸手术患者呼吸系统、循环系统相对稳定,而且术后用药少、拔管早、进食早、活动早、恢复快、但肺部并发症稍多.结论 胸腔镜下冠状动脉搭桥较正中开胸护理相对简单,减少了工作量少,提高了护理工作效率,且患者术后创伤小,疼痛轻,恢复快,住IcU时间明显缩短.

  9. Opening switches for a 5 MJ, 1 MA energy storage transformer

    Science.gov (United States)

    Clements, Neal D.; Johnson, Donald E.

    1991-01-01

    Two possible switch topologies used to switch the primary of an energy storage transformer are compared. A series-connected semiconductor/vacuum interrupter switch and an all-solid-state switch are sized for a 5-MJ energy storage transformer. Gate-turn-off (GTO) thyristors are used as the semiconductor switches. Total mass estimates, operating characteristics, and applicability to a space-based pulsed power system are discussed. Both designs store the commutation energy in capacitors. The commutation energy is then dissipated in resistors after switching has occurred. The capacitor mass is shown to dominate the total switch mass. Therefore, the mass of both switches is approximately equal. The advantages of the all-solid-state switch include high reliability, no moving parts, proven design, and a high probability of future mass reduction with new semiconductor device developments. The all-solid-state switch has a higher On-state power dissipation than the vacuum interrupter switch. It is suggested that the advantages of the all-solid-state switch outweigh the disadvantages of the higher power dissipation.

  10. Effect of the switching time on the performance of an adsorption chiller

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sang Woo; Chung, Jae Dong [Sejong University, Seoul (Korea, Republic of); Kwon, Oh Kyung [Korea Institute of Industrial Technology, Chonan (Korea, Republic of)

    2016-05-15

    The switching time is an important operating condition that must be correctly anticipated for an effective adsorption cooling system. Before the adsorption (or desorption) process begins, time is required to cool down (or heat up) the bed temperature so that the bed pressure reaches the evaporator pressure (or condenser pressure). During the switching time, the supplied heat is reduced and pressure overload conditions can be avoided. The switching time cannot be estimated early on, and an improper switching time degrades the system performance. Thus, this study provides guideline with which to determine the required time to open this valve, i.e., the switching time, and carefully examines the thermo-physical behavior in the adsorption bed during this period. A two-dimensional numerical method with the composite sorbent of SWS-1L and a water pair is applied to a fin-tube type adsorption chiller. Three cases of no switching time, the optimal switching time and a double the optimal switching time are examined. The results show that no consideration of the switching time overestimates the performance of the adsorption cooling system in terms of the Coefficient of performance (COP) and the Specific cooling power (SCP). On the other hand, if the switching time exceeds the optimal value, the performance of the adsorption cooling system is also reduced compared to that when using the optimal switching time. The dependency of the optimal switching times on various design parameters, such as the fin pitch, fin height and heating temperature, is also examined.

  11. Electrostatically actuated resonant switches for earthquake detection

    KAUST Repository

    Ramini, Abdallah H.

    2013-04-01

    The modeling and design of electrostatically actuated resonant switches (EARS) for earthquake and seismic applications are presented. The basic concepts are based on operating an electrically actuated resonator close to instability bands of frequency, where it is forced to collapse (pull-in) if operated within these bands. By careful tuning, the resonator can be made to enter the instability zone upon the detection of the earthquake signal, thereby pulling-in as a switch. Such a switching action can be functionalized for useful functionalities, such as shutting off gas pipelines in the case of earthquakes, or can be used to activate a network of sensors for seismic activity recording in health monitoring applications. By placing a resonator on a printed circuit board (PCB) of a natural frequency close to that of the earthquake\\'s frequency, we show significant improvement on the detection limit of the EARS lowering it considerably to less than 60% of the EARS by itself without the PCB. © 2013 IEEE.

  12. Microsurgical anatomy of the middle cerebral artery

    Directory of Open Access Journals (Sweden)

    Pai S

    2005-01-01

    Full Text Available Background: The microsurgical anatomy of the middle cerebral artery (MCA is of particular interest to the cerebrovascular surgeon. The purpose of this study was to define the microsurgical anatomy of the MCA and its various branches in the Indian population. Methods: Ten MCAs were studied from five cadaveric brain specimens. The authors studied the outer diameter, length, branches, perforators and site of these on the main trunk (M1, the division of the main trunk, the secondary trunks and their various cortical branches using the operating microscope under 5-20x magnification. Results: The outer diameter of the MCA main trunk ranges from 2.5 to 4 mm with a mean of 3.35 mm. The superolateral branches consisted of polar temporal artery and anterior temporal artery that had a common origin and sometimes the uncal artery or the accessory uncal artery. Perforators or lenticulostriate arteries were seen in the inferomedial surface all along the length of M1. Eight bifurcations and two trifurcations were noted. Cortical branches and their origin are discussed. Conclusion: Although the microsurgical anatomy of the MCA in Indian population correlated with the findings in the western literature, some structural and statistical variations were noted.

  13. Dynamics and Control of Switched Electronic Systems Advanced Perspectives for Modeling, Simulation and Control of Power Converters

    CERN Document Server

    Iannelli, Luigi

    2012-01-01

    The increased efficiency and quality constraints imposed on electrical energy systems have inspired a renewed research interest in the study of formal approaches to the analysis and control of power electronics converters. Switched systems represent a useful framework for modeling these converters and the peculiarities of their operating conditions and control goals justify the specific classification of “switched electronic systems”. Indeed, idealized switched models of power converters introduce problems not commonly encountered when analyzing generic switched models or non-switched electrical networks. In that sense the analysis of switched electronic systems represents a source for new ideas and benchmarks for switched and hybrid systems generally. Dynamics and Control of Switched Electronic Systems draws on the expertise of an international group of expert contributors to give an overview of recent advances in the modeling, simulation and control of switched electronic systems. The reader is provided...

  14. Arterial hypoxaemia in cirrhosis

    DEFF Research Database (Denmark)

    Møller, S; Hillingsø, Jens; Christensen, E

    1998-01-01

    BACKGROUND: Although low arterial oxygen tension (Po2) has been claimed to occur in one to two thirds of patients with cirrhosis, hypoxaemia appears to be rare in clinical practice. AIMS: To assess the frequency of arterial hypoxaemia in cirrhosis in relation to clinical and haemodynamic......%, 96%, 96%, and 93% (NS). So2 was below the lower limit of 92% in 0%, 9%, 7%, and 24% (p arterial carbon dioxide tension, a low systemic vascular...... resistance, and a low indocyanine green clearance (p arterial hypoxaemia in cirrhosis is about 22% in patients without encephalopathy, but it varies from 10-40% depending on the degree of hepatic dysfunction. Arterial hypoxaemia in patients with cirrhosis of differing...

  15. Artery by Neuropeptides

    Directory of Open Access Journals (Sweden)

    Esmeralda Sofia Costa Delgado

    2012-01-01

    Methods. Isolated rabbit eyes (n=12 were perfused in situ with tyrode through the external ophthalmic artery. Effects of intra-arterial injections of NPY 200 μg/ml (Group A; n=6 and VIP 200 μg/ml (Group B; n=6 on the recorded pressure were obtained. For statistical analysis, Student's paired t-test and Fast Fourier Transform were used. Results. Spontaneous oscillations were observed before any drug administration in the 12 rabbit models. NPY produced an increase in total vascular resistance and a higher frequency and amplitude of oscillations, while VIP evoked the opposite effects. Conclusions. This study provides evidence of vasomotion in basal conditions in rabbit external ophthalmic artery. Concerning drug effects, NPY increased arterial resistance and enhanced vasomotion while VIP produced opposite effects which demonstrates their profound influence in arterial vasomotion.

  16. Performance Limits of Nanoelectromechanical Switches (NEMS-Based Adiabatic Logic Circuits

    Directory of Open Access Journals (Sweden)

    Samer Houri

    2013-12-01

    Full Text Available This paper qualitatively explores the performance limits, i.e., energy vs. frequency, of adiabatic logic circuits based on nanoelectromechanical (NEM switches. It is shown that the contact resistance and the electro-mechanical switching behavior of the NEM switches dictate the performance of such circuits. Simplified analytical expressions are derived based on a 1-dimensional reduced order model (ROM of the switch; the results given by this simplified model are compared to classical CMOS-based, and sub-threshold CMOS-based adiabatic logic circuits. NEMS-based circuits and CMOS-based circuits show different optimum operating conditions, depending on the device parameters and circuit operating frequency.

  17. Simulation on Soft-Switching PWM Converter with High Power Factor

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new PWM converter based on soft-switching is introduced. The converter uses a minimum number of devices, and requires less switching operations than conventional techniques. Switching is realized solely in a ZVS (zero voltage switching) mode,therefore the loss is reduced and EMI (electromagnetic interference) is suppressed. The paper analyzes the operation of ZVS, and discusses the methods for maintaining a unit power factor and constant DC voltage. Changing the modulation index M and the phase angle θ keeps the input current in phase with the voltage. It also keeps the current sinusoidal, and ensures a constant output voltage.

  18. Proposal for all-optical controllable switch using dipole induced transparency (DIT)

    Science.gov (United States)

    Eftekhari, K.; Abbasian, K.; Rostami, A.

    2010-05-01

    We propose a novel all-optical controllable switch using photonic crystal cavity. For doing this work, the dipole induced transparency phenomenon realized through interaction of light with multilevel nanocrystals is used. Multilevel nanocrystals are doped to photonic crystal rods. Using the proposed structure and applying the control field, the absorbing medium converts to transparent one and switching operation is obtained. Analytical relation for evaluation of the proposed device considering quantum optical effects is presented and studied by investigation of effects of parameters on switching characteristics. We show that high quality all-optical switching operation can be obtained.

  19. Recent developments in switching theory

    CERN Document Server

    Mukhopadhyay, Amar

    2013-01-01

    Electrical Science Series: Recent Developments in Switching Theory covers the progress in the study of the switching theory. The book discusses the simplified proof of Post's theorem on completeness of logic primitives; the role of feedback in combinational switching circuits; and the systematic procedure for the design of Lupanov decoding networks. The text also describes the classical results on counting theorems and their application to the classification of switching functions under different notions of equivalence, including linear and affine equivalences. The development of abstract har

  20. Noise-induced coherent switch

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Taking the famous genetic toggle switch as an example,we numerically investigated the effect of noise on bistability.We found that extrinsic noise resulting from stochastic fluctuations in synthesis and degradation rates and from the environmental fluctuation in gene regulatory processes can induce coherent switch,and that there is an optimal noise intensity such that the noise not only can induce this switch,but also can amplify a weak input signal.In addition,we found that the intrinsic noise introduced through the Poisson τ-leap algorithm cannot induce such a switch.

  1. Low power all optical switches

    Institute of Scientific and Technical Information of China (English)

    Alireza Bananej; LI Chun-fei 李淳飞

    2004-01-01

    In this paper, we propose a new design of all fiber optical switches by using a high finesse ring resonator (RR) side coupled Mach-Zehnder interferometer. We will show that by compensating the total loss in the RR the switching power can be decreased greatly and by loss, compensating the bistability effect in RR can be cancelled and the switching performance can be improved. In addition, we will show that by using Erbium doped fiber for fabricating the RR we can obtain switching power threshold in mW range.

  2. Software Switching for Data Acquisition

    CERN Document Server

    CERN. Geneva; Malone, David

    2016-01-01

    In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

  3. Metabolic alterations and neurodevelopmental outcome of infants with transposition of the great arteries.

    Science.gov (United States)

    Park, I Sook; Yoon, S Young; Min, J Yeon; Kim, Y Hwue; Ko, J Kok; Kim, K Soo; Seo, D Man; Lee, J Hee

    2006-01-01

    Abnormal neurodevelopment has been reported for infants who were born with transposition of the great arteries (TGA) and underwent arterial switch operation (ASO). This study evaluates the cerebral metabolism of TGA infants at birth and before ASO and neurodevelopment 1 year after ASO. Proton magnetic resonance spectroscopy (1H-MRS) was performed on 16 full-term TGA brains before ASO within 3-6 days after birth. The brain metabolite ratios of [NAA/Cr], [Cho/Cr], and [mI/Cr] evaluated measured. Ten infants were evaluated at 1 year using the Bayley Scales of Infants Development II (BSED II). Cerebral metabolism of infants with TGA was altered in parietal white matter (PWM) and occipital gray matter (OGM) at birth before ASO. One year after ASO, [Cho/Cr] in PWM remained altered, but all metabolic ratios in OGM were normal. The results of BSID II at 1 year showed delayed mental and psychomotor development. This delayed neurodevelopmental outcome may reflect consequences of the altered cerebral metabolism in PWM measured by 1H-MRS. It is speculated that the abnormal hemodynamics due to TGA in utero may be responsible for the impaired cerebral metabolism and the subsequent neurodevelopmental deficit.

  4. Node design in optical packet switched networks

    DEFF Research Database (Denmark)

    Nord, Martin

    2006-01-01

    The thesis discusses motivation, realisation and performance of the Optical Packet Switching (OPS) network paradigm. The work includes proposals for designs and methods to efficiently use both the wavelength- and time domain for contention resolution in asynchronous operation. The project has also...... adapting network performance to the different acceptable packet loss rate levels of supported applications, while improving overall bandwidth efficiency. The project has evaluated QoS differentiation methods and proposed schemes with improved efficiency, which also include jitter sensitivity as a Qo...... proposed parallel designs to overcome scalability constraints and to support migration scenarios. Furthermore, it has proposed and demonstrated optical input processing schemes for hybrids networks to simultaneously support OPS and Optical Circuit Switching. Quality of Service (QoS) differentiation enables...

  5. Asymptotically thermal responses for smoothly switched detectors

    CERN Document Server

    Fewster, Christopher J; Louko, Jorma

    2015-01-01

    Thermal phenomena in quantum field theory can be detected with the aid of particle detectors coupled to quantum fields along stationary worldlines, by testing whether the response of such a detector satisfies the detailed balance version of the KMS condition at a constant temperature. This relation holds when the interaction between the field and the detector has infinite time duration. Operationally, however, detectors interact with fields for a finite amount of time, controlled by a switching function of compact support, and the KMS detailed balance condition cannot hold exactly for finite time interactions at arbitrarily large detector energy gap. In this large energy gap regime, we show that, for an adiabatically switched Rindler detector, the Unruh temperature emerges asymptotically after the detector and the field have interacted for a time that is polynomially long in the large energy. We comment on the significance of the adiabaticity assumption in this result.

  6. High current density contacts for photoconductive semiconductor switches

    Energy Technology Data Exchange (ETDEWEB)

    Baca, A.G.; Hjalmarson, H.P.; Loubriel, G.M.; McLaughlin, D.L.; Zutavern, F.J.

    1993-08-01

    The current densities implied by current filaments in GaAs photoconductive semiconductor switches (PCSS) are in excess of 1 MA/cm{sup 2}. As the lateral switches are tested repeatedly, damage accumulates at the contacts until electrical breakdown occurs across the surface of the insulating region. In order to improve the switch lifetime, the incorporation of n- and p-type ohmic contacts in lateral switches as well as surface geometry modifications have been investigated. By using p-type AuBe ohmic contacts at the anode and n-type AuGe ohmic contacts at the cathode, contact lifetime improvements of 5--10x were observed compared to switches with n-type contacts at both anode and cathode. Failure analysis on samples operated for 1--1,000 shots show that extensive damage still exists for at least one contact on all switches observed and that temperatures approaching 500{degrees}C are can be reached. However, the n-type AuGe cathode is often found to have no damage observable by scanning electron microscopy (SEM). The observed patterns of contact degradation indicate directions for future contact improvements in lateral switches.

  7. Scaling silicon photonic switch fabrics for data center interconnection networks.

    Science.gov (United States)

    Nikolova, Dessislava; Rumley, Sébastien; Calhoun, David; Li, Qi; Hendry, Robert; Samadi, Payman; Bergman, Keren

    2015-01-26

    With the rapidly increasing aggregate bandwidth requirements of data centers there is a growing interest in the insertion of optically interconnected networks with high-radix transparent optical switch fabrics. Silicon photonics is a particularly promising and applicable technology due to its small footprint, CMOS compatibility, high bandwidth density, and the potential for nanosecond scale dynamic connectivity. In this paper we analyze the feasibility of building silicon photonic microring based switch fabrics for data center scale optical interconnection networks. We evaluate the scalability of a microring based switch fabric for WDM signals. Critical parameters including crosstalk, insertion loss and switching speed are analyzed, and their sensitivity with respect to device parameters is examined. We show that optimization of physical layer parameters can reduce crosstalk and increase switch fabric scalability. Our analysis indicates that with current state-of-the-art devices, a high radix 128 × 128 silicon photonic single chip switch fabric with tolerable power penalty is feasible. The applicability of silicon photonic microrings for data center switching is further supported via review of microring operations and control demonstrations. The challenges and opportunities for this technology platform are discussed.

  8. Synthetical Control Strategy for Smooth Switching Between Grid-Connected and Islanded Operation Modes of Microgrid Based on Energy Storage System%基于储能的微网并网和孤岛运行模式平滑切换综合控制策略

    Institute of Scientific and Technical Information of China (English)

    赵冬梅; 张楠; 刘燕华; 张旭

    2013-01-01

    微网技术是解决分布式发电系统并网问题的有效途径之一,基于风光储互补的微网系统具有充分利用清洁能源和运行可靠的特点.微网的并网和孤岛运行模式之间的平滑切换是安全稳定运行的重要保障.为此,采用新型的主从和对等控制相结合的综合控制策略,对微网的并网/孤岛运行模式的过渡进行控制.在DigSILENT/PowerFactory平台上搭建风光储互补的微网模型,仿真结果验证了该控制策略的可行性.%Microgrid is an effective approach to solve the grid-connection of distributed generations, and the hybrid microgrid composed of wind farm, photovoltaic generation and energy storage system possesses the feature that the clean energy can be fully utilized and its operation is reliable. The smooth switching between grid-connected operation mode and islanded operation mode of microgrid is an important measure to ensure the secure and reliable operation of microgrid. For this reason, a synthetical control strategy integrating new type of master-slave control with peer-to-peer control is adopted to control the operation mode transition between grid-connected operation mode and islanded operation mode of microgrid. A model of microgrid composed of complementary wind farm, photovoltaic generation and energy storage system is constructed on DigSILENT/PowerFactory platform, and the feasibility of the proposed control strategy is verified by simulation results. Besides, simulation results also show that the improved control strategy can ensure power balance of microgrid before and after the switching and keep the voltage of the bus connected with microgrid and frequency of the microgrid within the allowed range.

  9. Tuning the temperature dependence for switching in dithienylethene photochromic switches.

    Science.gov (United States)

    Kudernac, Tibor; Kobayashi, Takao; Uyama, Ayaka; Uchida, Kingo; Nakamura, Shinichiro; Feringa, Ben L

    2013-08-29

    Diarylethene photochromic switches use light to drive structural changes through reversible electrocyclization reactions. High efficiency in dynamic photoswitching is a prerequisite for applications, as is thermal stability and the selective addressability of both isomers ring-opened and -closed diarylethenes. These properties can be optimized readily through rational variation in molecular structure. The efficiency with regard to switching as a function of structural variation is much less understood, with the exception of geometric requirements placed on the reacting atoms. Ultimately, increasing the quantum efficiency of photochemical switching in diarylethenes requires a detailed understanding of the excited-state potential energy surface(s) and the mechanisms involved in switching. Through studies of the temperature dependence, photoswitching and theoretical studies demonstrate the occurrence or absence of thermal activation barriers in three constitutional isomers that bear distinct π-conjugated systems. We found that a decrease in the thermal barriers correlates with an increase in switching efficiency. The origin of the barriers is assigned to the decrease in π-conjugation that is concomitant with the progress of the photoreaction. Furthermore, we show that balanced molecular design can minimize the change in the extent of π-conjugation during switching and lead to optimal bidirectional switching efficiencies. Our findings hold implications for future structural design of diarylethene photochromic switches.

  10. High Frequency Soft Switching Of PWM Boost Converter Using Auxiliary Resonant Circuit

    Directory of Open Access Journals (Sweden)

    C. P. Sai Kiran

    2014-10-01

    Full Text Available This thesis presents High frequency Soft Switching DC-DC boost Converter. The circuit consists of a general Boost Converter with an additional resonant circuit which has a switch, inductor, capacitor and a diode.In general Boost Converter circuits have snubber circuits where switching losses are dissipated in external passive resistors; which is known as hard switching. As the switching frequency of PWM converters is increased its switching losses and conduction losses also increases. This restricts the use of PWM technique. New Zero Voltage Transition-Zero Current Transition (ZVT-ZCT PWM converter equipped with the snubber provides the most desirable features of both ZVT and ZCT converters presented previously. Moreover all semiconductors devices operate with soft switching and hence losses are reduced.

  11. Wireless Chalcogenide Nanoionic-Based Radio-Frequency Switch

    Science.gov (United States)

    Nessel, James; Miranda, Felix

    2013-01-01

    A new nonvolatile nanoionic switch is powered and controlled through wireless radio-frequency (RF) transmission. A thin layer of chalcogenide glass doped with a metal ion, such as silver, comprises the operational portion of the switch. For the switch to function, an oxidizable electrode is made positive (anode) with respect to an opposing electrode (cathode) when sufficient bias, typically on the order of a few tenths of a volt or more, is applied. This action causes the metal ions to flow toward the cathode through a coordinated hopping mechanism. At the cathode, a reduction reaction occurs to form a metal deposit. This metal deposit creates a conductive path that bridges the gap between electrodes to turn the switch on. Once this conductive path is formed, no further power is required to maintain it. To reverse this process, the metal deposit is made positive with respect to the original oxidizable electrode, causing the dissolution of the metal bridge thereby turning the switch off. Once the metal deposit has been completely dissolved, the process self-terminates. This switching process features the following attributes. It requires very little to change states (i.e., on and off). Furthermore, no power is required to maintain the states; hence, the state of the switch is nonvolatile. Because of these attributes the integration of a rectenna to provide the necessary power and control is unique to this embodiment. A rectenna, or rectifying antenna, generates DC power from an incident RF signal. The low voltages and power required for the nanoionic switch control are easily generated from this system and provide the switch with a novel capability to be operated and powered from an external wireless device. In one realization, an RF signal of a specific frequency can be used to set the switch into an off state, while another frequency can be used to set the switch to an on state. The wireless, miniaturized, and nomoving- part features of this switch make it

  12. Hybrid switch for resonant power converters

    Science.gov (United States)

    Lai, Jih-Sheng; Yu, Wensong

    2014-09-09

    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  13. Medium voltage switching techniques; Techniques de coupure en moyenne tension

    Energy Technology Data Exchange (ETDEWEB)

    Theoleyre, S. [Schneider Electric S.A., 92 - Boulogne-Billancourt (France)

    1999-08-01

    The link between power production plants and users is ensured by a grid or an arborescence of connections, lines and cables. For exploitation, maintenance or safety reasons it may be necessary to switch off and switch on the current at any point of the network. Switching devices are used for this purpose and the choice of a given device depends on the nature of the current (load, overload and fault currents) and of the domain of application. During switching and during continuous operation, these devices are submitted to dielectric, thermal, electrodynamical and mechanical stresses. The most important stresses are those linked with transient phenomena and involving an electric arc. This paper deals principally with the switching of medium voltage (1 to 52 kV) AC currents using circuit breakers. The first part analyzes the phenomena that occur during the operation of circuit breakers while the second part presents the four switching techniques currently used: in air, oil, vacuum and in sulfur hexafluoride (SF{sub 6}). (J.S.) 35 refs.

  14. A Low-Cost CMOS Programmable Temperature Switch.

    Science.gov (United States)

    Li, Yunlong; Wu, Nanjian

    2008-05-15

    A novel uncalibrated CMOS programmable temperature switch with high temperature accuracy is presented. Its threshold temperature Tth can be programmed by adjusting the ratios of width and length of the transistors. The operating principles of the temperature switch circuit is theoretically explained. A floating gate neural MOS circuit is designed to compensate automatically the threshold temperature Tth variation that results form the process tolerance. The switch circuit is implemented in a standard 0.35 μm CMOS process. The temperature switch can be programmed to perform the switch operation at 16 different threshold temperature Tths from 45-120°C with a 5°C increment. The measurement shows a good consistency in the threshold temperatures. The chip core area is 0.04 mm² and power consumption is 3.1 μA at 3.3V power supply. The advantages of the temperature switch are low power consumption, the programmable threshold temperature and the controllable hysteresis.

  15. A Low-Cost CMOS Programmable Temperature Switch

    Directory of Open Access Journals (Sweden)

    Nanjian Wu

    2008-05-01

    Full Text Available A novel uncalibrated CMOS programmable temperature switch with high temperature accuracy is presented. Its threshold temperature Tth can be programmed by adjusting the ratios of width and length of the transistors. The operating principles of the temperature switch circuit is theoretically explained. A floating gate neural MOS circuit is designed to compensate automatically the threshold temperature Tth variation that results form the process tolerance. The switch circuit is implemented in a standard 0.35 μm CMOS process. The temperature switch can be programmed to perform the switch operation at 16 different threshold temperature Tths from 45-120°C with a 5°C increment. The measurement shows a good consistency in the threshold temperatures. The chip core area is 0.04 mm2 and power consumption is 3.1 μA at 3.3V power supply. The advantages of the temperature switch are low power consumption, the programmable threshold temperature and the controllable hysteresis.

  16. Magnonic interferometric switch for multi-valued logic circuits

    Science.gov (United States)

    Balynsky, Michael; Kozhevnikov, Alexander; Khivintsev, Yuri; Bhowmick, Tonmoy; Gutierrez, David; Chiang, Howard; Dudko, Galina; Filimonov, Yuri; Liu, Guanxiong; Jiang, Chenglong; Balandin, Alexander A.; Lake, Roger; Khitun, Alexander

    2017-01-01

    We investigated a possible use of the magnonic interferometric switches in multi-valued logic circuits. The switch is a three-terminal device consisting of two spin channels where input, control, and output signals are spin waves. Signal modulation is achieved via the interference between the source and gate spin waves. We report experimental data on a micrometer scale prototype based on the Y3Fe2(FeO4)3 structure. The output characteristics are measured at different angles of the bias magnetic field. The On/Off ratio of the prototype exceeds 13 dB at room temperature. Experimental data are complemented by the theoretical analysis and the results of micro magnetic simulations showing spin wave propagation in a micrometer size magnetic junction. We also present the results of numerical modeling illustrating the operation of a nanometer-size switch consisting of just 20 spins in the source-drain channel. The utilization of spin wave interference as a switching mechanism makes it possible to build nanometer-scale logic gates, and minimize energy per operation, which is limited only by the noise margin. The utilization of phase in addition to amplitude for information encoding offers an innovative route towards multi-state logic circuits. We describe possible implementation of the three-value logic circuits based on the magnonic interferometric switches. The advantages and shortcomings inherent in interferometric switches are also discussed.

  17. Arcuate ligament syndrome inducing hepatic artery thrombosis after liver transplantation

    Institute of Scientific and Technical Information of China (English)

    Zhi-Jun Jiang; Ting-Bo Liang; Xiao-Ning Feng; Wei-Lin Wang; Yan Shen; Min Zhang; Jian Wu; Xiao Xu; Shu-Sen Zheng

    2008-01-01

    BACKGROUND: Hepatic artery thrombosis (HAT) is a frequent complication following liver transplantation, but it is rarely caused by arcuate ligament compression of the celiac artery. This article mainly describes our experience in managing a patient with celiac artery stenosis and HAT after liver transplantation. METHODS: A 44-year-old man with a 15-year history of hepatitis B was admitted to our hospital for hepatocellular carcinoma. Before the operation, he received trans-arterial chemoembolization once, and pretransplant MR angiography indicated a suspected stenosis at the initiation of the celiac artery, while color Doppler showed normal blood lfow in the arterial system. In this case, orthotopic liver transplantation was performed for radical cure of hepatocellular carcinoma. However, B-ultrasonography detected poor blood lfow in the intra- and extra-hepatic artery on the ifrst posttransplant day, and during exploratory laparotomy a thrombus was found in the hepatic artery. Thus, re-transplantation was conducted with a bypass between the graft hepatic artery and the recipient abdominal aorta with the donor's splenic artery. RESULTS: The patient made an uneventful recovery and color Doppler showed good blood lfow in the artery and portal system. Histology conifrmed extensive thrombosis in the left and right hepatic artery of the explanted graft, indicating HAT. CONCLUSIONS: Although HAT caused by celiac trunk compression is rarely reported in liver transplantation, the diagnosis should be considered in patients with pretransplant hepatic artery stenosis on angiography and abnormal blood lfow on B-ultrasonography. Once HAT is formed, treatment such as thrombectomy or re-transplantation should be performed as early as possible.

  18. Low voltage drop plasma switch for inverter and modulator applications

    Science.gov (United States)

    Goebel, D. M.; Poeschel, R. L.; Schumacher, R. W.

    1993-08-01

    A low forward voltage drop plasma switch has been developed for high-efficiency inverter and modulator applications. The switch, called the HOLLOTRON, is based on a grid-controlled, thermionic hollow-cathode discharge. A low forward voltage drop (10-20 V) is achieved by operating the hollow-cathode discharge in a static gas pressure of xenon. The dense plasma generated in the Ba-oxide dispenser hollow cathode is spread over a relatively large control grid area by a diverging magnetic field superimposed on the discharge. Interruption of the discharge current at high current densities (≳4 A/cm2) over the grid area is achieved by biasing the control grid sufficiently negative with respect to the plasma. The HOLLOTRON switch has demonstrated voltage stand-off of up to 20 kV, switching times of ≤0.3 μs, and pulse repetition frequencies of 20 kHz at 50% duty.

  19. Metal-to-metal-switches for large currents

    Energy Technology Data Exchange (ETDEWEB)

    Schade, D.W.; Weise, T.H.G.G.; Braunsberger, U.E.; Salge, J.G.H. (Inst. fuer Hochspannungstechnik, Technische Univ. Braunschweig, Postfach 3329, D-3300 Braunschweig (DE))

    1991-01-01

    The operation of electromagnetic rail launchers requires switching large currents. For rail gun accelerators with driving currents of some MA it is important to keep the resistance of the total energy supply circuit small compared to that of the moving projectile, which is velocity dependent and low. Among the great variety of switches which can be used for this purpose those with metallic contacts offer the advantage that their ohmic resistance in the closed position can be kept more than an order of magnitude smaller than gas discharge or solid state switches. The paper reviews existing metal contact switches, originally developed mainly for nuclear fusion research experiments, and discusses their properties with respect to an application in large capacitor banks for linear mass accelerators.

  20. Resistive switching memory based on bioinspired natural solid polymer electrolytes.

    Science.gov (United States)

    Raeis Hosseini, Niloufar; Lee, Jang-Sik

    2015-01-27

    A solution-processed, chitosan-based resistive-switching memory device is demonstrated with Pt/Ag-doped chitosan/Ag structure. The memory device shows reproducible and reliable bipolar resistive switching characteristics. A memory device based on natural organic material is a promising device toward the next generation of nonvolatile nanoelectronics. The memory device based on chitosan as a natural solid polymer electrolyte can be switched reproducibly between high and low resistance states. In addition, the data retention measurement confirmed the reliability of the chitosan-based nonvolatile memory device. The transparent Ag-embedded chitosan film showed an acceptable and comparable resistive switching behavior on the flexible plastic substrate as well. A cost-effective, environmentally benign memory device using chitosan satisfies the functional requirements of nonvolatile memory operations.

  1. EIT-based MZ-MMI all-optical switch

    Science.gov (United States)

    Bahrami, A.; Rostami, A.; Nazari, F.; Abbasian, K.

    2010-11-01

    We propose a new control structure for all-optical switching in multimode inference (MMI)-based Mach-Zehnder interferometer (MZI) devices. This structure is composed of an MZI doped by three-level nanocrystals for the realization of electromagnetically induced transparency (EIT) in the lower arm. We use two different intensities of control field for two states of the proposed switch. Using a control field in both of the two switching states is necessary, where the EIT region is transparent. By changing the intensity of the control field, the refractive index of the doped region changes, which makes the phase difference between the two arms of the MZI. Hence, the switching operation takes place. Simulation results show that the extinction ratio of the device is -32dB in the worst case.

  2. Femtosecond-scale switching based on excited free-carriers

    CERN Document Server

    Sivan, Y; Yuce, E; Mosk, A P

    2015-01-01

    We describe novel optical switching schemes operating at femtosecond time scales by employing free carrier (FC) excitation. Such unprecedented switching times are made possible by spatially patterning the density of the excited FCs. In the first realization, we rely on diffusion, i.e., on the nonlocality of the FC nonlinear response of the semiconductor, to erase the initial FC pattern and, thereby, eliminate the reflectivity of the system. In the second realization, we erase the FC pattern by launching a second pump pulse at a controlled delay. We discuss the advantages and limitations of the proposed approaches and demonstrate their potential applicability for switching ultrashort pulses propagating in silicon waveguides. We show switching efficiencies of up to $50\\%$ for $100$ fs pump pulses, which is an unusually high level of efficiency for such a short interaction time, a result of the use of the strong FC nonlinearity. Due to limitations of saturation and pattern effects, these schemes can be employed ...

  3. High bandwidth all-optical 3×3 switch based on multimode interference structures

    Science.gov (United States)

    Le, Duy-Tien; Truong, Cao-Dung; Le, Trung-Thanh

    2017-03-01

    A high bandwidth all-optical 3×3 switch based on general interference multimode interference (GI-MMI) structure is proposed in this study. Two 3×3 multimode interference couplers are cascaded to realize an all-optical switch operating at both wavelengths of 1550 nm and 1310 nm. Two nonlinear directional couplers at two outer-arms of the structure are used as all-optical phase shifters to achieve all switching states and to control the switching states. Analytical expressions for switching operation using the transfer matrix method are presented. The beam propagation method (BPM) is used to design and optimize the whole structure. The optimal design of the all-optical phase shifters and 3×3 MMI couplers are carried out to reduce the switching power and loss.

  4. EDITORIAL: Molecular switches at surfaces Molecular switches at surfaces

    Science.gov (United States)

    Weinelt, Martin; von Oppen, Felix

    2012-10-01

    In nature, molecules exploit interaction with their environment to realize complex functionalities on the nanometer length scale. Physical, chemical and/or biological specificity is frequently achieved by the switching of molecules between microscopically different states. Paradigmatic examples are the energy production in proton pumps of bacteria or the signal conversion in human vision, which rely on switching molecules between different configurations or conformations by external stimuli. The remarkable reproducibility and unparalleled fatigue resistance of these natural processes makes it highly desirable to emulate nature and develop artificial systems with molecular functionalities. A promising avenue towards this goal is to anchor the molecular switches at surfaces, offering new pathways to control their functional properties, to apply electrical contacts, or to integrate switches into larger systems. Anchoring at surfaces allows one to access the full range from individual molecular switches to self-assembled monolayers of well-defined geometry and to customize the coupling between molecules and substrate or between adsorbed molecules. Progress in this field requires both synthesis and preparation of appropriate molecular systems and control over suitable external stimuli, such as light, heat, or electrical currents. To optimize switching and generate function, it is essential to unravel the geometric structure, the electronic properties and the dynamic interactions of the molecular switches on surfaces. This special section, Molecular Switches at Surfaces, collects 17 contributions describing different aspects of this research field. They analyze elementary processes, both in single molecules and in ensembles of molecules, which involve molecular switching and concomitant changes of optical, electronic, or magnetic properties. Two topical reviews summarize the current status, including both challenges and achievements in the field of molecular switches on

  5. Coronary artery aneurysms

    Energy Technology Data Exchange (ETDEWEB)

    Koischwitz, D.; Harder, T.; Schuppan, U.; Thurn, P.

    1982-04-01

    Seven saccular coronary artery aneurysms have been demonstrated in the course of 1452 selective coronary artery angiograms. In six patients they were arterio-sclerotic; in one patient the aneurysm must have been congenital or of mycotic-embolic origin. The differential diagnosis between true aneurysms and other causes of vascular dilatation is discussed. Coronary artery aneurysms have a poor prognosis because of the possibility of rupture with resultant cardiac tamponade, or the development of thrombo-embolic myocardial infarction. These aneurysms can only be diagnosed by means of coronary angiography and require appropriate treatment.

  6. Coronary Artery Bypass

    Directory of Open Access Journals (Sweden)

    Kadri Ceberut

    2011-01-01

    Full Text Available Ancient schwannoma is a rare variant of neural tumors though rarely seen in the thorax. The combination with coronary artery diseases is also rare. Here we describe a 66 year-old male who had undergone one-stage combined surgery for thoracic ancient schwannomas removal and coronary artery disease. The masses were, respectively, 13 cm in the middle mediastinum and 5 cm in diameter originating from the intercostal nerve. The tumors were successfully removed using sternotomy, and then a coronary artery bypass grafting was performed. Here we discuss this rare tumor in relation to the relevant literature.

  7. Molecule-Based Rheology Switching

    NARCIS (Netherlands)

    Paulusse, Jos M.J.; Sijbesma, Rint P.

    2006-01-01

    Sound-activated switching: The rheological behavior of fluids can be affected by external stimuli, as demonstrated by electrochemically and photochemically induced changes in viscosity and sol–gel transitions. Recently, ultrasound has emerged as a novel rheology switch for supramolecular polymers an

  8. Topology optimized RF MEMS switches

    DEFF Research Database (Denmark)

    Philippine, M. A.; Zareie, H.; Sigmund, Ole

    2013-01-01

    optimization for an RF MEM capacitive switch. Extensive experimental data confirms that the switches perform as designed by the optimizations, and that our simulation models are accurate. A subset of measurements are presented here. Broader results have been submitted in full journal format....

  9. Battery switch for downhole tools

    Science.gov (United States)

    Boling, Brian E.

    2010-02-23

    An electrical circuit for a downhole tool may include a battery, a load electrically connected to the battery, and at least one switch electrically connected in series with the battery and to the load. The at least one switch may be configured to close when a tool temperature exceeds a selected temperature.

  10. Active Photonic Crystal Switches: Modeling, Design and Experimental Characterization

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Yu, Yi; Kristensen, Philip Trøst;

    2013-01-01

    In this paper, we present recent progress in modeling, design, fabrication and experimental characterization of InP photonic crystal all-optical switches. Novel designs with increased flexibility and performance are presented, and their operation using high speed data signals is analyzed numerica......In this paper, we present recent progress in modeling, design, fabrication and experimental characterization of InP photonic crystal all-optical switches. Novel designs with increased flexibility and performance are presented, and their operation using high speed data signals is analyzed...

  11. Optimized scalable network switch

    Science.gov (United States)

    Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.

    2010-02-23

    In a massively parallel computing system having a plurality of nodes configured in m multi-dimensions, each node including a computing device, a method for routing packets towards their destination nodes is provided which includes generating at least one of a 2m plurality of compact bit vectors containing information derived from downstream nodes. A multilevel arbitration process in which downstream information stored in the compact vectors, such as link status information and fullness of downstream buffers, is used to determine a preferred direction and virtual channel for packet transmission. Preferred direction ranges are encoded and virtual channels are selected by examining the plurality of compact bit vectors. This dynamic routing method eliminates the necessity of routing tables, thus enhancing scalability of the switch.

  12. Acute Myocardial Infarction after Switching from Warfarin to Dabigatran

    Directory of Open Access Journals (Sweden)

    Wael Abuzeid

    2015-01-01

    Full Text Available Dabigatran etexilate is a recently approved direct thrombin inhibitor (DTI, which is superior to warfarin in the prevention of stroke and systemic embolism in patients with atrial fibrillation (AF. However, dabigatran use is associated with an increased risk of myocardial infarction (MI compared to warfarin. The mechanisms for this association effect remain speculative. We present a case of an acute MI and cardiac arrest in a patient with chronic AF who had been recently switched from warfarin to dabigatran. Urgent coronary angiography, at St. Michael’s hospital (Toronto, Canada, revealed evidence of thromboembolism to the distal posterior descending artery. The patient was treated medically and switched back from dabigatran to warfarin. He did well and was discharged after an uneventful stay in the coronary care unit.

  13. Electromagnetic actuation in MEMS switches

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de; Mátéfi-Tempfli, Mária; Chemnitz, Steffen

    Power electronics takes use of switches in order to convert and manage energy. The ideal switch with low power loss consists of electromechanic relays, but since they are bulky and expensive, semiconductors switches are more widely used for power electronic applications, resulting in power losses...... during energy conversion. Micro-Electro-Mechanical Systems (MEMS) consist of miniaturized mechanical and/or electro-mechanical elements fabricated using microfabrication techniques, and are good candidates for achieving a miniaturized electromechanic switch at the micro-scale with very little power loss...... generation of reliable MEMS and power MEMS devices. We have investigated deposition of these films via electroplating and its magnetic properties, along with the feasibility for integration into MEMS switches, and the results are presented in this work....

  14. Relationship of white matter network topology and cognitive outcome in adolescents with d-transposition of the great arteries.

    Science.gov (United States)

    Panigrahy, Ashok; Schmithorst, Vincent J; Wisnowski, Jessica L; Watson, Christopher G; Bellinger, David C; Newburger, Jane W; Rivkin, Michael J

    2015-01-01

    Patients with congenital heart disease (CHD) are at risk for neurocognitive impairments. Little is known about the impact of CHD on the organization of large-scale brain networks. We applied graph analysis techniques to diffusion tensor imaging (DTI) data obtained from 49 adolescents with dextro-transposition of the great arteries (d-TGA) repaired with the arterial switch operation in early infancy and 29 healthy referent adolescents. We examined whether differences in neurocognitive functioning were related to white matter network topology. We developed mediation models revealing the respective contributions of peri-operative variables and network topology on cognitive outcome. Adolescents with d-TGA had reduced global efficiency at a trend level (p = 0.061), increased modularity (p = 0.012), and increased small-worldness (p = 0.026) as compared to controls. Moreover, these network properties mediated neurocognitive differences between the d-TGA and referent adolescents across every domain assessed. Finally, structural network topology mediated the neuroprotective effect of longer duration of core cooling during reparative neonatal cardiac surgery, as well as the detrimental effects of prolonged hospitalization. Taken together, worse neurocognitive function in adolescents with d-TGA is mediated by global differences in white matter network topology, suggesting that disruption of this configuration of large-scale networks drives neurocognitive dysfunction. These data provide new insights into the interplay between perioperative factors, brain organization, and cognition in patients with complex CHD.

  15. Relationship of white matter network topology and cognitive outcome in adolescents with d-transposition of the great arteries

    Directory of Open Access Journals (Sweden)

    Ashok Panigrahy

    2015-01-01

    Full Text Available Patients with congenital heart disease (CHD are at risk for neurocognitive impairments. Little is known about the impact of CHD on the organization of large-scale brain networks. We applied graph analysis techniques to diffusion tensor imaging (DTI data obtained from 49 adolescents with dextro-transposition of the great arteries (d-TGA repaired with the arterial switch operation in early infancy and 29 healthy referent adolescents. We examined whether differences in neurocognitive functioning were related to white matter network topology. We developed mediation models revealing the respective contributions of peri-operative variables and network topology on cognitive outcome. Adolescents with d-TGA had reduced global efficiency at a trend level (p = 0.061, increased modularity (p = 0.012, and increased small-worldness (p = 0.026 as compared to controls. Moreover, these network properties mediated neurocognitive differences between the d-TGA and referent adolescents across every domain assessed. Finally, structural network topology mediated the neuroprotective effect of longer duration of core cooling during reparative neonatal cardiac surgery, as well as the detrimental effects of prolonged hospitalization. Taken together, worse neurocognitive function in adolescents with d-TGA is mediated by global differences in white matter network topology, suggesting that disruption of this configuration of large-scale networks drives neurocognitive dysfunction. These data provide new insights into the interplay between perioperative factors, brain organization, and cognition in patients with complex CHD.

  16. Single coronary artery anomaly: the left main coronary artery originating from the proximal segment of right coronary artery

    Institute of Scientific and Technical Information of China (English)

    ZHU Jun; QIN Xu-guang; WU Qing-yu; XIONG Wei-guo; LU Chun-peng; WANG Rong-feng

    2011-01-01

    This case report we presented is that the anomalous left main coronary artery (LMCA) originates from the proximal segment of right coronary artery. In order to confirm the origin and course of the anomalous LMCA, a multi-slice computed tomography (MSCT) of the heart was performed on a 64-slice machine (Philips 64 Slice, Philips, USA) after 6 months of coronary angiography operation. The results showed that the anomalous LMCA originates from the proximal segment of right coronary artery, lies posteriorly to the aorta before taking acute sharply to go between the aorta and left atrium. It was classified as R-Ⅱ P subtype according to Lipton's classification. It is a rare case in the clinical practice.

  17. Buffer allocation in an ATM switch with output buffer and speed constraints

    Science.gov (United States)

    Gupta, Anil K.; Georganas, N. D.

    A synchronous nonblocking N times N switch for asynchronous transfer mode (ATM) networks or high speed packet switching networks transporting fixed length packets called cells is considered. Such a switch with output queuing achieves the optimal performance, however it requires the switch fabric to work at the speed of N. In practice the switch may operate L times faster than the input/output trunk. It is assumed that queues at each output port have a limited buffer space and whenever an output queue is full, the back-pressure is applied and the packets are retained at the head of the input queues. The upper bound on the packet loss probability at the input queues in such a switch are computed. To achieve a given packet loss rate, the switch with L equals 2 requires almost the same amount of input and output buffers as with L equals 4 up to 70 percent input load, but as the load increases beyond 70 percent the switch with L equals 4 would require more output buffers and less input buffers in comparison with a switch operating at L equals 2. The performance of a switch with L equals 3 is very similar to that for L equals 4 and is not considered.

  18. Dynamic contrast-enhanced ultrasound and transient arterial occlusion for quantification of arterial perfusion reserve in peripheral arterial disease

    Energy Technology Data Exchange (ETDEWEB)

    Amarteifio, E., E-mail: erick.amarteifio@med.uni-heidelberg.de [University Hospital of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Wormsbecher, S. [University Hospital of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Krix, M. [University Hospital of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Bracco Imaging Germany, Konstanz (Germany); Demirel, S. [University Hospital of Heidelberg, Department of Vascular Surgery, Heidelberg (Germany); Braun, S. [Department of Biostatistics, German Cancer Research Center, Heidelberg (Germany); Delorme, S. [Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Boeckler, D. [University Hospital of Heidelberg, Department of Vascular Surgery, Heidelberg (Germany); Kauczor, H.-U. [University Hospital of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Weber, M.-A. [University Hospital of Heidelberg, Department of Diagnostic and Interventional Radiology, Heidelberg (Germany); Department of Radiology, German Cancer Research Center, Heidelberg (Germany)

    2012-11-15

    Objective: To quantify muscular micro-perfusion and arterial perfusion reserve in peripheral arterial disease (PAD) with dynamic contrast-enhanced ultrasound (CEUS) and transient arterial occlusion. Materials and methods: This study had local institutional review board approval and written informed consent was obtained from all subjects. We examined the dominant lower leg of 40 PAD Fontaine stage IIb patients (mean age, 65 years) and 40 healthy volunteers (mean age, 54 years) with CEUS (7 MHz; MI, 0.28) during continuous intravenous infusion of 4.8 mL microbubbles. Transient arterial occlusion at mid-thigh level simulated physical exercise. With time-CEUS-intensity curves obtained from regions of interest within calf muscles, we derived the maximum CEUS signal after occlusion (max) and its time (t{sub max}), slope to maximum (m), vascular response after occlusion (AUC{sub post}), and analysed accuracy, receiver operating characteristic (ROC) curves, and correlations with ankle-brachial index (ABI) and walking distance. Results: All parameters differed in PAD and volunteers (p < 0.014). In PAD, t{sub max} was delayed (31.2 {+-} 13.6 vs. 16.7 {+-} 8.5 s, p < 0.0001) and negatively correlated with ankle-brachial-index (r = -0.65). m was decreased in PAD (4.3 {+-} 4.6 mL/s vs. 13.1 {+-} 8.4 mL/s, p < 0.0001) and had highest diagnostic accuracy (sensitivity/specificity, 75%/93%) for detection of diminished muscular micro-perfusion in PAD (cut-off value, m < 5{approx}mL/s). Discriminant analysis and ROC curves revealed m, and AUC{sub post} as optimal parameter combination for diagnosing PAD and therefore impaired arterial perfusion reserve. Conclusions: Dynamic CEUS with transient arterial occlusion quantifies muscular micro-perfusion and arterial perfusion reserve. The technique is accurate to diagnose PAD.

  19. Renal arteries (image)

    Science.gov (United States)

    A renal angiogram is a test used to examine the blood vessels of the kidneys. The test is performed ... main vessel of the pelvis, up to the renal artery that leads into the kidney. Contrast medium ...

  20. Coronary Artery Bypass Surgery

    Science.gov (United States)

    ... t help, you may need coronary artery bypass surgery. The surgery creates a new path for blood to flow ... more than one bypass. The results of the surgery usually are excellent. Many people remain symptom-free ...

  1. Carotid Artery Disease

    Science.gov (United States)

    ... make them more vulnerable to damage. Tobacco use. Nicotine can irritate the inner lining of your arteries. ... your physical and mental capabilities such as strength, memory and speech. After that, your doctor may recommend: ...

  2. Pulmonary Arterial Hypertension

    Science.gov (United States)

    Pulmonary Arterial Hypertension What Is Pulmonary Hypertension? To understand pulmonary hypertension (PH) it helps to understand how blood ows throughout your body. While the heart is one organ, it ...

  3. Heritability of cilioretinal arteries

    DEFF Research Database (Denmark)

    Taarnhøj, Nina Charlotte; Munch, Inger C; Kyvik, Kirsten O;

    2005-01-01

    PURPOSE: To determine whether the presence of one or more cilioretinal arteries, a distinct element of the pattern of fundus vessels, is genetically programmed, influenced by environmental factors, or the result of random mechanisms of vascular development. METHODS: The fundi of 112 pairs...... environmental factors. CONCLUSIONS: The presence or absence of one or more cilioretinal arteries in healthy persons is markedly influenced by genetic factors....

  4. Model Reduction of Switched Systems Based on Switching Generalized Gramians

    DEFF Research Database (Denmark)

    Shaker, Hamid Reza; Wisniewski, Rafal

    2012-01-01

    In this paper, a general method for model order reduction of discrete-time switched linear systems is presented. The proposed technique uses switching generalized gramians. It is shown that several classical reduction methods can be developed into the generalized gramian framework for the model r......-Galerkin projection is constructed instead of the similarity transform approach for reduction. It is proven that the proposed reduction framework preserves the stability of the original switched system. The performance of the method is illustrated by numerical examples....

  5. Fuzzy logic mode switching in helicopters

    Science.gov (United States)

    Sherman, Porter D.; Warburton, Frank W.

    1993-01-01

    The application of fuzzy logic to a wide range of control problems has been gaining momentum internationally, fueled by a concentrated Japanese effort. Advanced Research & Development within the Engineering Department at Sikorsky Aircraft undertook a fuzzy logic research effort designed to evaluate how effective fuzzy logic control might be in relation to helicopter operations. The mode switching module in the advanced flight control portion of Sikorsky's motion based simulator was identified as a good candidate problem because it was simple to understand and contained imprecise (fuzzy) decision criteria. The purpose of the switching module is to aid a helicopter pilot in entering and leaving coordinated turns while in flight. The criteria that determine the transitions between modes are imprecise and depend on the varied ranges of three flight conditions (i.e., simulated parameters): Commanded Rate, Duration, and Roll Attitude. The parameters were given fuzzy ranges and used as input variables to a fuzzy rulebase containing the knowledge of mode switching. The fuzzy control program was integrated into a real time interactive helicopter simulation tool. Optimization of the heading hold and turn coordination was accomplished by interactive pilot simulation testing of the handling quality performance of the helicopter dynamic model. The fuzzy logic code satisfied all the requirements of this candidate control problem.

  6. Nanofiber-based all-optical switches

    CERN Document Server

    Kien, Fam Le

    2016-01-01

    We study all-optical switches operating on a single four-level atom with the $N$-type transition configuration in a two-mode nanofiber cavity with a significant length (on the order of $20$ mm) and a moderate finesse (on the order of 300) under the electromagnetically induced transparency (EIT) conditions. In our model, the gate and probe fields are the quantum nanofiber-cavity fields excited by weak classical light pulses, and the parameters of the $D_2$ line of atomic cesium are used. We examine two different switching schemes. The first scheme is based on the effect of the presence of a photon in the gate mode on the EIT of the probe mode. The second scheme is based on the use of EIT to store a photon of the gate mode in the population of an appropriate atomic level, which leads to the reduction of the transmission of the field in the probe mode. We investigate the dependencies of the switching contrast on various parameters, such as the cavity length, the mirror reflectivity, and the detunings and powers ...

  7. Cathode heating mechanisms in pseudospark plasma switches

    Science.gov (United States)

    Sommerer, Timothy J.; Pak, Hoyoung; Kushner, Mark J.

    1992-10-01

    Pseudosparks, and the back-lighted thyratron (BLT) in particular, are finding increasing application as pulse power switches. An attractive feature of BLTs is that high current densities (≥ tens of kA cm-2) can be sustained from metal cathodes without auxiliary heating. The source of this current is believed to be electric-field-enhanced thermionic emission resulting from heating of the cathode by ion bombardment during commutation which ultimately melts the surface of the cathode. It is proposed that a photon-driven ionization mechanism in the interelectrode gap of the BLT is responsible for initiating the observed patterns of cathode surface melting and electron emission. A 21/2-dimensional computer model is presented that incorporates a photo-induced ionization mechanism to spread the plasma into the interelectrode gap. It predicts a melting of the cathode in a pattern similar to that which is experimentally observed, and predicts a rate of field-enhanced thermionic electron emission that is sufficient to explain the high BLT conduction current density. In the absence of these mechanisms, the model does not predict the observed large-area melting of the face of the cathode. The cathode heating rate during the BLT switching phase is maximum for operating parameters that are very close to the limit for which the switch will close (that is, the smallest possible pressure-electrode spacing product and smallest possible electrode holes).

  8. Performance Test of Openflow Agent on Openflow Software-Based Mikrotik RB750 Switch

    Directory of Open Access Journals (Sweden)

    Rikie Kartadie

    2016-11-01

    Full Text Available A network is usually developed by several devices such as router, switch etc. Every device forwards data package manipulation with complicated protocol planted in its hardware. An operator is responsible for running configuration either to manage rules or application applied in the network. Human error may occur when device configuration run manually by operator. Some famous vendors, one of them is MikroTik, has also been implementing this OpenFlow on its operation. It provides the implementation of SDN/OpenFlow architecture with affordable cost. The second phase research result showed that switch OF software-based MikroTik resulted higher latency value than both mininet and switch OF software-based OpenWRT. The average gap value of switch OF software-based MikroTik is 2012 kbps lower than the value of switch OF software-based OpenWRT. The average gap value of throughput bandwidth protocol UDP switch OF software-based MikroTik is 3.6176 kBps lower than switch OF software-based OpenWRT and it is 8.68 kBps lower than mininet. The average gap throughput jitter protokol UDP of switch OF software-based MiktoTik is 0.0103ms lower than switch OF software-based OpenWRT and 0.0093ms lower than mininet. 

  9. Noninvasive evaluation of peripheral arterial disease.

    Science.gov (United States)

    Barnes, R W

    1978-08-01

    Doppler ultrasound is the most simple, inexpensive, accurate and versatile of the available noninvasive screening techniques to assess peripheral vascular diseases. The four fundamental components of peripheral arterial evaluation with this technique are assessment of blood velocity signal, measurement of resting ankle pressure, determination of segmental leg blood pressures, and measurement of ankle pressure response to exercise or reactive hyperemia. Plethysmography permits graphic recording of pulse-wave morphology, determination of digit blood pressure, and pulsatile responses to compression maneuvers. These techniques are useful in objectively quantifying peripheral arterial occlusive disease, predicting the results of operative therapy, monitoring the success of arterial reconstruction during surgery, and following the physiologic status of the patient after surgery.

  10. Multiple vascular anomalies involving renal, testicular and suprarenal arteries

    Directory of Open Access Journals (Sweden)

    Suresh Rao

    2015-09-01

    Full Text Available Knowledge of variations of blood vessels of the abdomen is important during operative, diagnostic and endovascular pro- cedures. During routine dissection of the abdominal cavity, we came across multiple vascular anomalies involving renal, suprarenal and testicular arteries. The left kidney was supplied by two renal arteries originating together from the abdomi- nal aorta, and the right kidney was supplied by two accessory renal arteries, one of which was arising from the right renal artery and the other one from the aorta (about 2 inches below the origin of the renal artery. Accessory renal veins were present on both sides. The right testicular artery was arising from the lower accessory renal artery. The left testicular artery was looping around the inferior tributary of the left renal vein, whereby forming a sharp kink. The left middle suprarenal artery was diving into three small branches; the upper two branches were supplying the left suprarenal gland, whereas the lower branch was supplying the left kidney. Furthermore, detailed literature and the clinical and surgical importance of the case are discussed. [Arch Clin Exp Surg 2015; 4(3.000: 168-171

  11. Additional renal arteries: incidence and morphometry.

    Science.gov (United States)

    Satyapal, K S; Haffejee, A A; Singh, B; Ramsaroop, L; Robbs, J V; Kalideen, J M

    2001-01-01

    Advances in surgical and uro-radiological techniques dictate a reappraisal and definition of renal arterial variations. This retrospective study aimed at establishing the incidence of additional renal arteries. Two subsets were analysed viz.: a) Clinical series--130 renal angiograms performed on renal transplant donors, 32 cadaver kidneys used in renal transplantation b) Cadaveric series--74 en-bloc morphologically normal kidney pairs. The sex and race distribution was: males 140, females 96; African 84, Indian 91, White 43 and "Coloured" 18, respectively. Incidence of first and second additional arteries were respectively, 23.2% (R: 18.6%; L: 27.6%) and 4.5% (R: 4.7%; L: 4.4%). Additional arteries occurred more frequently on the left (L: 32.0%; R: 23.3%). The incidence bilaterally was 10.2% (first additional arteries, only). The sex and race incidence (first and second additional) was: males, 28.0%, 5.1%; females, 16.4%, 3.8% and African 31.1%, 5.4%; Indian 13.5%, 4.5%; White 30.9%, 4.4% and "Coloured" 18.5%, 0%; respectively. Significant differences in the incidence of first additional arteries were noted between sex and race. The morphometry of additional renal arteries were lengths (cm) of first and second additional renal arteries: 4.5 and 3.8 (right), 4.9 and 3.7 (left); diameters: 0.4 and 0.3 (right), 0.3 and 0.3 (left). Detailed morphometry of sex and race were also recorded. No statistically significant differences were noted. Our results of the incidence of additional renal arteries of 27.7% compared favourably to that reported in the literature (weighted mean 28.1%). The study is unique in recording detailed morphometry of these vessels. Careful techniques in the identification of this anatomical variation is important since it impacts on renal transplantation surgery, vascular operations for renal artery stenosis, reno-vascular hypertension, Takayasu's disease, renal trauma and uro-radiological procedures.

  12. Implementation of remote monitoring and managing switches

    Science.gov (United States)

    Leng, Junmin; Fu, Guo

    2010-12-01

    In order to strengthen the safety performance of the network and provide the big convenience and efficiency for the operator and the manager, the system of remote monitoring and managing switches has been designed and achieved using the advanced network technology and present network resources. The fast speed Internet Protocol Cameras (FS IP Camera) is selected, which has 32-bit RSIC embedded processor and can support a number of protocols. An Optimal image compress algorithm Motion-JPEG is adopted so that high resolution images can be transmitted by narrow network bandwidth. The architecture of the whole monitoring and managing system is designed and implemented according to the current infrastructure of the network and switches. The control and administrative software is projected. The dynamical webpage Java Server Pages (JSP) development platform is utilized in the system. SQL (Structured Query Language) Server database is applied to save and access images information, network messages and users' data. The reliability and security of the system is further strengthened by the access control. The software in the system is made to be cross-platform so that multiple operating systems (UNIX, Linux and Windows operating systems) are supported. The application of the system can greatly reduce manpower cost, and can quickly find and solve problems.

  13. Three-terminal nanoelectromechanical switch based on tungsten nitride—an amorphous metallic material

    KAUST Repository

    Mayet, Abdulilah M.

    2015-12-04

    © 2016 IOP Publishing Ltd. Nanoelectromechanical (NEM) switches inherently have zero off-state leakage current and nearly ideal sub-threshold swing due to their mechanical nature of operation, in contrast to semiconductor switches. A challenge for NEM switches to be practical for low-power digital logic application is their relatively large operation voltage which can result in higher dynamic power consumption. Herein we report a three-terminal laterally actuated NEM switch fabricated with an amorphous metallic material: tungsten nitride (WNx). As-deposited WNx thin films have high Young\\'s modulus (300 GPa) and reasonably high hardness (3 GPa), which are advantageous for high wear resistance. The first prototype WNx switches are demonstrated to operate with relatively low control voltage, down to 0.8 V for an air gap thickness of 150 nm.

  14. Three-terminal nanoelectromechanical switch based on tungsten nitride—an amorphous metallic material

    Science.gov (United States)

    Mayet, Abdulilah M.; Hussain, Aftab M.; Hussain, Muhammad M.

    2016-01-01

    Nanoelectromechanical (NEM) switches inherently have zero off-state leakage current and nearly ideal sub-threshold swing due to their mechanical nature of operation, in contrast to semiconductor switches. A challenge for NEM switches to be practical for low-power digital logic application is their relatively large operation voltage which can result in higher dynamic power consumption. Herein we report a three-terminal laterally actuated NEM switch fabricated with an amorphous metallic material: tungsten nitride (WN x ). As-deposited WN x thin films have high Young’s modulus (300 GPa) and reasonably high hardness (3 GPa), which are advantageous for high wear resistance. The first prototype WN x switches are demonstrated to operate with relatively low control voltage, down to 0.8 V for an air gap thickness of 150 nm.

  15. Surgical treatment of anomalous origin of coronary artery from the pulmonary artery

    Institute of Scientific and Technical Information of China (English)

    WU Qing-yu; XU Zhong-hua

    2008-01-01

    Background Anomalous origin of coronary artery from the pulmonary artery is a rare congenial cardiac malformation with a mortality rate of up to 90% within the first year of life without surgical intervention. Direct implantation of the anomalous coronary artery (ACA)into the aorta is successful in early life, but it may have increased surgical difficulty and risk with age. This retrospective study summarized our operative experience in direct implantation for treatment of this coronary anomaly in pediatric and adult patients. Methods From August 2000 to January 2003. 4 consecutive patients aged from 9 months to 41 years underwent dual coronary repair. Among them, two children and one infant with anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA)and one adult was anomalous origin of right coronary artery from the pulmonary artery(ARCAPA). Coronary arteries were directly implanted into the ascending aorta in 4 patients. In a boy with ALCAPA associated with moderate mitral insufficiency(MI), whose ACA arose remotely from the ascending aorta, we created a tube-shaped graft using part of the pulmonary arterial wall in continuity with the origin of the left coronary artery (LCA). Concomitant moderate MI was repaired in 2 patients, including this boy, after a dual-coronary repair. Results All patients survived. There were no hospital or late deaths and no major complications as well. Echocardiography revealed that the left ventricular (LV)function including LV end-diastolic dimension(EDD)and ejection fraction(EF)was markedly improved at hospital discharge. At 3-6 years follow-up after surgery all patients were asymptomatic and currently in NYHA class I. Conclusions The best results are achieved with direct implantation of the ACA into the ascending aorta and simultaneous mitral valve repair if needed. Direct implantation is feasible in pediatric and adult patients with ALCAPA or ARCAPA including the coronary artery in a location remote from

  16. Switching behavior in Peramlloy/Niobium/Permalloy trilayer

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Tae Jong; Kim, Dong Ho [Yeungnam University, Gyeongsan (Korea, Republic of)

    2014-12-15

    We have investigated the effect of temperature and bias current on the stability of the inverse spin-switch effect in Permalloy(Py)/Nb/Permalloy pseudo spin-valves. The inverse spin-switch operates between two orientations of the ferromagnetic moments of Py layers; parallel (ON) and antiparallel-domain (OFF) state. Measuring time scans of the resistance changes between the ON and OFF state, ΔR{sub O}N{sub -O}FF, while alternating magnetic fields between the two states at various temperatures and bias currents, revealed that enhancement of ΔR{sub O}N{sub -O}FF is a key factor to achieve successful operation of superconducting spin switch.

  17. Tuning the Temperature Dependence for Switching in Dithienylethene Photochromic Switches

    NARCIS (Netherlands)

    Kudernac, Tibor; Kobayashi, Takao; Uyama, Ayaka; Uchida, Kingo; Nakamura, Shinichiro; Feringa, Ben L.

    2013-01-01

    Diarylethene photochromic switches use light to drive structural changes through reversible electrocyclization reactions. High efficiency in dynamic photoswitching is a prerequisite for applications, as is thermal stability and the selective addressability of both isomers ring-opened and -closed dia

  18. Coronary anomaly: the single coronary artery

    Institute of Scientific and Technical Information of China (English)

    QIN Xu-guang; XIONG Wei-guo; LU Chun-peng; GONG Cheng-jie; SHANG Li-hua

    2010-01-01

    @@ Single coronary artery (SCA), defined as an artery that arises from the arterial trunk and nourishes the entire myocardium, is rare. We report two cases of SCA, one is the right coronary artery (RCA) originating from the middle of left descending artery (LAD), and the other is the left main coronary artery (LMCA) arising from the proximal right coronary artery.

  19. Switching Processes in Queueing Models

    CERN Document Server

    Anisimov, Vladimir V

    2008-01-01

    Switching processes, invented by the author in 1977, is the main tool used in the investigation of traffic problems from automotive to telecommunications. The title provides a new approach to low traffic problems based on the analysis of flows of rare events and queuing models. In the case of fast switching, averaging principle and diffusion approximation results are proved and applied to the investigation of transient phenomena for wide classes of overloading queuing networks.  The book is devoted to developing the asymptotic theory for the class of switching queuing models which covers  mode

  20. Coronary Artery and Pulmonary Artery Fistula Originated from Significant Stenosis in the Left Anterior Descending Artery

    Directory of Open Access Journals (Sweden)

    Alper Sami Kunt

    2013-01-01

    Full Text Available Coronary artery fistula (CAF is defined as a rare anomalous connection between a coronary artery and a major vessel or a cardiac chamber. We report a case of a left anterior descending coronary (LAD stenosis and coronary artery fistula between the LAD coronary artery and the pulmonary artery (PA. CAF is often diagnosed by coronary angiogram. We describe our diagnostic approach and review the literature on the epidemiology, the pathophysiology, the diagnostic modalities, and the treatment options.

  1. Fundamental scaling properties of electro-mechanical switches

    Science.gov (United States)

    Knoll, A. W.; Grogg, D.; Despont, M.; Duerig, U.

    2012-12-01

    We discuss the fundamental processes including electron conduction and adhesion of metallic contacts pertaining to the scaling of the performance metrics of nano-electro-mechanical switches. In particular, we show that under most circumstances, the switching energy is governed by the force that is needed in order to break the electrical contact when opening the switch. For an optimally designed parallel plate capacitor switch, the energy consumption does not depend on the actuation voltage. However, stray capacitances degrade the energy efficiency if a high operating voltage is chosen. The limit is of the order of 1 V for an aggressively scaled Si device, for which an overall switching energy of the order of 150 eV, a footprint area of 2500 nm2 and a switching time of 200 ps are predicted. The scaling analysis also stipulates that materials with a low free electron density and high effective mass should be used for the electrical contact, which is counter-intuitive, as such materials are known to be poor conductors on the macroscopic scale.

  2. Light-Induced Switching of Tunable Single-Molecule Junctions

    KAUST Repository

    Sendler, Torsten

    2015-04-16

    A major goal of molecular electronics is the development and implementation of devices such as single-molecular switches. Here, measurements are presented that show the controlled in situ switching of diarylethene molecules from their nonconductive to conductive state in contact to gold nanoelectrodes via controlled light irradiation. Both the conductance and the quantum yield for switching of these molecules are within a range making the molecules suitable for actual devices. The conductance of the molecular junctions in the opened and closed states is characterized and the molecular level E 0, which dominates the current transport in the closed state, and its level broadening Γ are identified. The obtained results show a clear light-induced ring forming isomerization of the single-molecule junctions. Electron withdrawing side-groups lead to a reduction of conductance, but do not influence the efficiency of the switching mechanism. Quantum chemical calculations of the light-induced switching processes correlate these observations with the fundamentally different low-lying electronic states of the opened and closed forms and their comparably small modification by electron-withdrawing substituents. This full characterization of a molecular switch operated in a molecular junction is an important step toward the development of real molecular electronics devices.

  3. Optical Switching for Dynamic Distribution of Wireless-Over-Fiber Signals in Active Optical Networks

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Rodes, Guillermo; Tafur Monroy, Idelfonso

    2012-01-01

    of a four wavelength-division-multiplexed channel system operating on a WiMax frequency band and employing an orthogonal-frequency-division-multiplexing modulation at 625 Mbits/s per channel, transmission of the data over 20 km of optical fiber, and active switching in a 1 × 16 active optical switch...

  4. Analysis of Switching Transient Overvoltages in the Power System of Floating Production Storage and Offloading Vessel

    NARCIS (Netherlands)

    Xue, H.; Popov, M.

    2013-01-01

    Large transient overvoltages are normally caused by vacuum circuit breaker (VCB) switching operation during disconnection of induction motors. In this paper VCBs, cables, generators, busbars, induction motors and surge arresters are modeled by making use of ATP-EMTP. Switching transient overvoltages

  5. Modular space-vector pulse-width modulation for nine-switch converters

    DEFF Research Database (Denmark)

    Dehghan, Seyed Mohammad; Amiri, Arash; Mohamadian, Mustafa

    2013-01-01

    Recently, nine-switch inverter (NSI) has been presented as a dual-output inverter with constant frequency (CF) or different frequency (DF) operation modes. However, the CF mode is more interesting because of its lower switching device rating. This study proposes a new space-vector modulation (SVM...

  6. Reduction in electromagnetic interference of switching converters using self-excitation-chaos

    DEFF Research Database (Denmark)

    Li, Qingnan; Xiong, Rui; He, Ou

    2008-01-01

    We derived a second-order S-switching iterative map describing the dynamics of simple feedback Buck switching regulator operating in continuous mode. Analysis of this map shows that chaos and bifurcations may occur along with the changing of values of some system parameters. By making the converter...

  7. 240-kA switch with potential application in electromagnetic-launch systems

    Energy Technology Data Exchange (ETDEWEB)

    Honig, E.M.

    1983-01-01

    Electromagnetic (EM) launchers have severe switching requirements. Switching demands for railgun systems, for instance, inlcude current conduction from hundreds of kA to a few MA, conduction times of a ms to a few s, standoff voltages as high as a few tens of kV, to rcovery voltages of 1 to 10 kV after conduction, opening and closing duty, and repetitive operation up to about 50 Hz. These demands, particularly for repetitive opening duty, are far beyond the capability of most current switches and switching concepts. This paper will review the performance of rod array triggered vacuum gap (RATVG) switches and discuss their potential for solving switching problems in EM launcher systems. A new mode of operation for the RATVG switch is proposed. Fundamental considerations for the operation of opening switches and their associated transfer circuits are presented. Methods of recovering the railgun's inductive energy to enable efficient repetitive operation are discussed and new circuits with such capability are proposed.

  8. Ecological heating of switches. Pt. 1; Oekologische Beheizung von Weichen. T. 1

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Bernd

    2011-10-15

    To keep switches free from snow and ice is a requirement for a save and undisturbed railway operation during wintertime. Necessary demand of energy for melting ice and snow cause considerable costs to the railway infrastructure companies. Activities are going on to heat switches by means of renewable energy sources. Possible methods are discussed and evaluated. (orig.)

  9. 23 CFR 636.118 - Is team switching allowed after contract award?

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Is team switching allowed after contract award? 636.118 Section 636.118 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS DESIGN-BUILD CONTRACTING General § 636.118 Is team switching allowed after...

  10. Electrically switched ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, M.A. [Pacific Northwest National Lab., Richland, WA (United States); Schwartz, D.T.; Genders, D.

    1997-10-01

    A variety of waste types containing radioactive {sup 137}Cs are found throughout the DOE complex. These waste types include water in reactor cooling basins, radioactive high-level waste (HLW) in underground storage tanks, and groundwater. Safety and regulatory requirements and economics require the removal of radiocesium before these wastes can be permanently disposed of. Electrically Switched Ion Exchange (ESIX) is an approach for radioactive cesium separation that combines IX and electrochemistry to provide a selective, reversible, and economic separation method that also produces little or no secondary waste. In the ESIX process, an electroactive IX film is deposited electrochemically onto a high-surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. For cesium, the electroactive films under investigation are ferrocyanides, which are well known to have high selectivities for cesium in concentrated sodium solutions. When a cathode potential is applied to the film, Fe{sup +3} is reduced to the Fe{sup +2} state, and a cation must be intercalated into the film to maintain charge neutrality (i.e., Cs{sup +} is loaded). Conversely, if an anodic potential is applied, a cation must be released from the film (i.e., Cs{sup +} is unloaded). Therefore, to load the film with cesium, the film is simply reduced; to unload cesium, the film is oxidized.

  11. Application of Arterial Spin Labeling (ASL) Technique in the Pre Operative Evaluation of Brain Tumors%动脉自旋标记技术在脑肿瘤术前评估中的应用研究

    Institute of Scientific and Technical Information of China (English)

    朱记超; 娄明武; 张方璟; 赖文娟; 胡卫东; 范义; 陈燕萍

    2012-01-01

    目的 对比研究动态磁敏感对比增强(dynamic susceptibility contrast-enhanced,DSC) MRI及动脉自旋标记(aterial spin labeling,ASL)技术在脑肿瘤术前评估中的作用,探讨ASL技术在脑肿瘤术前评估中的应用价值. 方法 经病理证实的41例脑肿瘤患者,其中高级别胶质瘤8例,低级别胶质瘤16例,转移瘤7例,脑膜瘤10例.采用3.0TMR扫描仪行ASL流动敏感交互反转恢复(flow-sensitive alternating inversion recovery,FAIR)法及DSC灌注检查,将原始图像分析处理后分别获取肿瘤实性区域、瘤周1 cm及2 cm区域血流灌注指标平均最大相对脑血流量(rCBFmax)比值.所得数据经统计学处理,P<0.05为差异有统计学意义;对两种技术所得平均rCBFmax比值行线性回归分析,得出其相关系数,了解其相关性.结果 在肿瘤实性区域,两种技术所得rCBFmax低级别胶质瘤组与其他各组间差异均有统计学意义(P<0.05);在瘤旁1 cm区域,DSC技术所得rCBFmax高级别胶质瘤组与其他各组间差异均有统计学意义(P<0.05),而ASL技术rCBFmax在各组差异无统计学意义(P>0.05).两种技术所得rCBFmax在各组脑肿瘤瘤区实性区域与瘤旁1 cm及2 cm区域差异均有统计学意义(P<0.05).两种技术于肿瘤实性区域所得灌注指标显著正相关(r =0.907).结论 ASL技术是一种无需注射对比剂的MR灌注方法,可考虑作为常规检查方法评估脑肿瘤血流动力学情况,指导脑肿瘤术前级别评估.%Objective To explore the potential clinical application of arterial spin labeling (ASL) technique in the pre operative evaluation of brain tumors comparing with DSC MR imaging. Methods Forty one cases of brain tumors, including 8 high grade gliomas, 16 low grade gliomas, 7 metastases, and 10 meningiomas, performed flow-sensitive alternating inversion recovery(FAIR) and dynamic susceptibility contrast-enhanced (DSC) at a clinical 3.0 T MR imaging unit. All the cases were verified

  12. Electrical Breakdown Physics in Photoconductive Semiconductor Switches (PCSS).

    Energy Technology Data Exchange (ETDEWEB)

    Mar, Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zutavern, Fred J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Vawter, Gregory A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hjalmarson, Harold P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gallegos, Richard Joseph [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bigman, Verle Howard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    of 200kV (DC) and 5kA current that can be stacked in parallel to achieve 100's of kA with 10e5 shot lifetime. The new vertical switch design configuration generates parallel filaments in the bulk GaAs (as opposed to just beneath the surface as in previous designs) to achieve breakdown fields close to the maximum for the bulk GaAs while operating in air, and with 2-D scalability of the number of current-sharing filaments. This design also may be highly compatible with 2-D VCSEL arrays for optical triggering. The demonstration of this design in this LDRD utilized standard thickness wafers to trigger 0.4kA at 35kV/cm (limited by 0.6mm wafer thickness), tested to 1e5 shots with no detectable degradation of switch performance. Higher fields, total current, and switching voltages would be achievable with thicker GaAs wafers. Another important application pursued in this LDRD is the use of PCSS for trigger generator applications. Conventional in-plane PCSS have achieved triggering of a 100kV sparkgap (Kinetech-type) switch of the type similar to switches being considered for accelerator upgrades. The trigger is also being developed for pulsed power for HPM applications that require miniaturization and robust performance in noisy compact environments. This has spawned new programs for developing this technology, including an STTR for VCSEL trigger laser integration, also pursuing other follow-on applications.

  13. Design and performance of the beamlet optical switch

    Energy Technology Data Exchange (ETDEWEB)

    Rhodes, M.A.; Woods, B.W.; DeYoreo, J.J. [and others

    1996-06-01

    High-energy lasers for Inertial Confinement Fusion (ICF) experiments are typically designed with large apertures (>30 cm) to keep the fluence below the damage threshold of the various optical components. Until recently, no optical switch technology could be scaled to the aperture size, aperture shape (square), and switching speed required for the next generation of ICF drivers. This step is critical: The Beamlet multipass amplifier cavity uses a full-aperture optical switch to trap the laser pulse within the cavity and to divert the pulse out of the cavity when it reaches the required energy. By rotating the polarization of the beam, a Pockels cell in the switch controls whether the beam is transmitted through, or reflected from, the polarizer. In this article the authors describe an optical switch technology that does scale to the required aperture size and shape for Beamlet and the porposed National Ignition Facility (NIF) laser, and can employ a thin crystal. This switch consists of a thin-film polarizer and a plasma-electrode Pockels cell (PEPC), the latter originally invented at Lawrence Livermore National Laboratory (LLNL) in the 1980s and under further development since 1991. After discussing the PEPC concept, they present the design and optical performance of a 32 x 32 cm{sup 2} prototype PEPC, including discussions of the crystals, the PEPC assembly, the vacuum and gas system, and the high-voltage pulsers. Then they describe the performance of the 37 x 37 cm{sup 2} PEPC construced specifically for the Beamlet laser. Finally, they discuss important technology issues that arose during PEPC development: cathode sputtering, cathode heating, nonuniformities in the switching profile, switch-pulse leakage current, and an estimate of the plasma density and temperature produced during PEPC operation.

  14. [Results of the surgical treatment of acute thrombosis of the major arteries of the limbs].

    Science.gov (United States)

    Ovchinnikov, V A; Vereshchagin, N A; Shavin, V V; Parakhoniak, N V

    1984-08-01

    An analysis of the surgical treatment of acute arterial trombosis of the extremities in 86 patients is presented. The causes of thrombosis were mainly obliterating atherosclerosis, artery trauma and postembolic occlusion. Best results of reconstructive operations were obtained in patients with postembolic occlusion of the arteries and their posttraumatic trombosis, worst results - in obliterating atherosclerosis. Thrombendarterectomy and autovenous shunts and prostheses were found to be the mos effective reconstructive operations.

  15. Single-photon all-optical switching using coupled microring resonators

    Indian Academy of Sciences (India)

    Wenge Yang; Amitabh Joshi; Min Xiao

    2007-08-01

    We study the nonlinear phase response of a microring resonator coupled to a bus waveguide and the use of this nonlinear phase shift to store information in the microring resonator and enhance the switching characteristics of a Mach–Zehnder interferometer (MZI). By introducing coupling between adjacent microring resonators, the switching characteristics of the MZI can be exponentially enhanced as a function of the number of microring resonators, when compared to the linear enhancement for uncoupled resonators. With only a few moderate-finesse microring resonators, the switching power can be reduced to attowatt level, allowing for photonic switching devices that operate at single-photon level in ordinary optical waveguides.

  16. Column Generation for Transmission Switching of Electricity Networks with Unit Commitment

    DEFF Research Database (Denmark)

    Villumsen, Jonas Christoffer; Philpott, Andy B.

    2011-01-01

    This paper presents the problem of finding the minimum cost dispatch and commitment of power generation units in a transmission network with active switching.We use the term active switching to denote the use of switches to optimize network topology in an operational context. We propose a Dantzig......-Wolfe reformulation and a novel column generation framework to solve the problem efficiently. Preliminary results are presented for the IEEE-118 bus network with 19 generator units. Active switching is shown to reduce total cost by up to 15 % for a particular 24-hour period. Furthermore, the need for generator...

  17. First-order reversal curve probing of spatially resolved polarization switching dynamics in ferroelectric nanocapacitors.

    Science.gov (United States)

    Kim, Yunseok; Kumar, Amit; Ovchinnikov, Oleg; Jesse, Stephen; Han, Hee; Pantel, Daniel; Vrejoiu, Ionela; Lee, Woo; Hesse, Dietrich; Alexe, Marin; Kalinin, Sergei V

    2012-01-24

    Spatially resolved polarization switching in ferroelectric nanocapacitors was studied on the sub-25 nm scale using the first-order reversal curve (FORC) method. The chosen capacitor geometry allows both high-veracity observation of the domain structure and mapping of polarization switching in a uniform field, synergistically combining microstructural observations and probing of uniform-field polarization responses as relevant to device operation. A classical Kolmogorov-Avrami-Ishibashi model has been adapted to the voltage domain, and the individual switching dynamics of the FORC response curves are well approximated by the adapted model. The comparison with microstructures suggests a strong spatial variability of the switching dynamics inside the nanocapacitors.

  18. A 4 × 4 Strictly Nonblocking Silicon-on-Insulator Thermo-Optic Switch Matrix

    Institute of Scientific and Technical Information of China (English)

    YANG Di; LI Yan-Ping; CHEN Shao-Wu; YU Jin-Zhong

    2005-01-01

    @@ A 4 × 4 strictly nonblocking thermo-optic switch matrix implemented with a 2 × 2 Mach-Zehnder switch unit was fabricated in silicon-on-insulator wafer. Insertion losses of the shortest and the longest path in the device are about 14.8dB and 19.2dB, respectively. The device presents a very low loss dependent on wavelength. For one switch unit, the power consumption needed for operation is measured to be 0.270 W-0.288 W and the switching time is about 13 ± 1μs.

  19. BRIEF COMMUNICATIONS: Multichannel semiconductor nanosecond switch for excitation of copper vapor by a transverse discharge

    Science.gov (United States)

    Aleksandrov, V. M.; Buzhinskiĭ, O. I.; Grekhov, Igor'V.; Levinshteĭn, M. E.; Moshkunov, A. I.; Sergeev, V. G.

    1981-01-01

    A high-power semiconductor nanosecond switch, in the form of a thyristor structure activated by a laser pulse, was investigated. This switch could handle currents up to ~5×10 kA under voltages of gtrsim 5 kV in a time of ~1 nsec. The principle of its operation ensured synchronous of triggering of several switches with an accuracy of 0.1-0.01 nsec. These switches could be connected in series and could be used effectively to pump lasers excited by transverse discharges.

  20. Scaling experiments on a magnetically insulated thermionic vacuum switch

    Energy Technology Data Exchange (ETDEWEB)

    Eninger, J.E.; Vanderberg, B.H. [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Industrial Electrotechnology

    1994-12-31

    Magnetic insulation of the electron flow in a cylindrical thermionic vacuum diode has been proposed as a way to achieve a fast high-voltage high-power opening switch. The expected performance of this type of device can be derived from a set of basic scaling laws combined with empirical relationships obtained from experimental studies. Switch losses are mainly due to anode dissipation W{sub a}, which can be normalized to the transferred pulse energy. Leakage current and switch hold-off voltage depend on device geometry, materials, vacuum conditions etc and must be determined experimentally. For this purpose, the MX-1 experiment has been designed and operated. This device is basically a smooth-bore cylindrical magnetron with a 5 cm radius, 400 cm{sup 2} area thermionic dispenser cathode separated from the coaxial water-cooled anode by a few mm wide gap. This design allows pulsed operation at up to {approximately}100 kV, {approximately}4 kA and average power levels of {approximately}1 MW. The MX-1 switch is used as an opening switch to produce 1--2 {mu}s long square pulses from an inductive storage PFN. The current-voltage characteristics of the switch are determined as a function of the applied magnetic field and load condition. Plasma wave measurements are performed to investigate the stability of the electron flow. Results are summarized in the form of scaling diagrams for the important switch parameters, showing possible performance levels and physical and technical limitations identified as far in this work.

  1. Coronary bypass revascularization with radial artery and internal mammary artery grafts

    Institute of Scientific and Technical Information of China (English)

    甄文俊; 佟宏峰; 王永忠; 孙耀光; 黄文; 马玉健; 田家政; 吴良洪

    2002-01-01

    Objective To evaluate radial artery (RA) and internal mammary artery (IMA) grafts in coronary artery bypass and the use of color Doppler ultrasound in the peri-operative evaluation of IMA and radial-ulnar collateral circulation.Methods From June 1998 to June 2000, sixty cases of coronary bypass revascularization with RA and IMA were performed. Preoperatively, the radial-ulnar collateral circulation was evaluated with the modified Allen's test, color Doppler ultrasound and noninvasive oxygen saturation measurement. The IMA lumen and blood flow were measured at the first intercostal space with color Doppler ultrasound preoperatively and postoperatively.Results One patient (1.7%) died of serious cardiac arrhythmia on the fourth postoperative day. There were no arterial graft harvest related complications. Before harvesting, the ulnar artery blood flow was 30.78±9.71?ml/min, and it increased to 43.36±13.98?ml/min (40.87% increase, P0.05), but the systolic/diastolic flow ratio markedly decreased from 8.57±3.98?ml/min to 3.41±4.87?ml/min (P<0.01).Conclusions Arterial grafts can be safely used for coronary bypass revascularization with good results. The ulnar artery blood flow can increase compensatively after RA harvesting. The diastolic blood flow of grafted IMA markedly increased postoperatively. Color Doppler ultrasound was very helpful both in evaluating the radial-ulnar collateral circulation before RA harvesting and in assessing the patency of the grafted IMA after coronary artery bypass grafting (CABG).

  2. Management of femoral artery pseudoaneurysm due to addictive drug injection

    Institute of Scientific and Technical Information of China (English)

    李建文; 王三明; 陈小东

    2004-01-01

    Objective: To study surgical management for patients with femoral pseudoaneurysm resulting from addictive druginjection.Methods: Clinical data of 34 patients with femoral pseudoaneurysm resulting from addictive drug injection were retrospectively reviewed.Results: Thirteen patients underwent bypass graft ( end to side) of external iliac artery and superficial femoral artery using expanded polytetrafluoroethylene (ePTFE).Three patients who had an autogenous saphenous vein graft in situs, one of whom was then performed an ePTFE graft when rupture and bleeding occurred at the anastomotic site. Color Doppler image showed patent grafted blood vessels in all the patients after operation. Eighteen patients had their femoral arteries ligated. Limbs of all the 34 patients were saved.Conclusions: Ligating femoral artery is an effective way to treat femoral artery pseudoaneurysm if autogenous saphenous vein graft or artificial vessel graft is notapplicable.

  3. 47 CFR 54.301 - Local switching support.

    Science.gov (United States)

    2010-10-01

    ... Assets Account 2110 Central Office Assets Accounts 2210, 2220, 2230 Central Office-switching, Category 3... 2690 II Rural Telephone Bank (RTB) Stock Included in Account 1410 Materials and Supplies Account 1220.1... Amortization Included in Accounts 2005, 2680, 2690, 3410 Net Deferred Operating Income Taxes Accounts...

  4. Low-frequency switching voltage regulators for terrestrial photovoltaic systems

    Science.gov (United States)

    Delombard, R.

    1984-01-01

    The photovoltaic technology project and the stand alone applications project are discussed. Two types of low frequency switching type regulators were investigated. The design, operating characteristics and field application of these regulators is described. The regulators are small in size, low in cost, very low in power dissipation, reliable and allow considerable flexibility in system design.

  5. Magnetically insulated opening switch research

    Science.gov (United States)

    McGeoch, M. W.; Kraft, R.

    1987-01-01

    We examine the feasibility of an opening switch concept based on magnetic insulation in a coaxial thermionic diode. It is found that the impedance ratio between closed and open states of the diode is marginal for efficient energy transfer via this type of switch. The open, or insulated state of the diode is characterized by current leakage across the magnetic field which is associated with the presence of plasma waves.

  6. A Piezoelectric Cryogenic Heat Switch

    Science.gov (United States)

    Jahromi, Amir E.; Sullivan, Dan F.

    2014-01-01

    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  7. Assumption or Fact? Line-to-Neutral Voltage Expression in an Unbalanced 3-Phase Circuit during Inverter Switching

    Science.gov (United States)

    Masrur, M. A.

    2009-01-01

    This paper discusses the situation in a 3-phase motor or any other 3-phase system operating under unbalanced operating conditions caused by an open fault in an inverter switch. A dc voltage source is assumed as the input to the inverter, and under faulty conditions of the inverter switch, the actual voltage applied between the line to neutral…

  8. Optimum Design of a Moving Coil Actuator for Fast-Switching Valves in Digital Hydraulic Pumps and Motors

    DEFF Research Database (Denmark)

    Roemer, Daniel Beck; Bech, Michael Møller; Johansen, Per

    2015-01-01

    Fast-switching seat valves suitable for digital hydraulic pumps and motors utilize direct electromagnetic actuators, which must exhibit superior transient performance to allow efficient operation of the fluid power pump/motor. A moving coil actuator resulting in a minimum valve switching time.......5 bar at 600 L/min flow rate, enabling efficient operation of digital hydraulic pumps and motors....

  9. A Switched Capacitor Based AC/DC Resonant Converter for High Frequency AC Power Generation

    Directory of Open Access Journals (Sweden)

    Cuidong Xu

    2015-09-01

    Full Text Available A switched capacitor based AC-DC resonant power converter is proposed for high frequency power generation output conversion. This converter is suitable for small scale, high frequency wind power generation. It has a high conversion ratio to provide a step down from high voltage to low voltage for easy use. The voltage conversion ratio of conventional switched capacitor power converters is fixed to n, 1/n or −1/n (n is the switched capacitor cell. In this paper, A circuit which can provide n, 1/n and 2n/m of the voltage conversion ratio is presented (n is stepping up the switched capacitor cell, m is stepping down the switching capacitor cell. The conversion ratio can be changed greatly by using only two switches. A resonant tank is used to assist in zero current switching, and hence the current spike, which usually exists in a classical switching switched capacitor converter, can be eliminated. Both easy operation and efficiency are possible. Principles of operation, computer simulations and experimental results of the proposed circuit are presented. General analysis and design methods are given. The experimental result verifies the theoretical analysis of high frequency AC power generation.

  10. A Novel Crowbar Impulse Current Circuit for Testing the Switch-Type SPD

    Institute of Scientific and Technical Information of China (English)

    YAO Xueling; CHEN Jingliang; SUN Wei

    2008-01-01

    A crowbar impulse current circuit for testing the switch-type surge protective device (SPD) is presented. The crowbar circuit consists of a computer control circuit, a trigger voltage pulse generator, a main discharging switch, and a crowbar pseudospark switch. The active trigger technology was studied in the crowbar impulse current circuit. The circuit monitors the main discharging current and generates a trigger signal at a proper time for the crowbar pseudospark switch operation. The trigger characteristics of the main discharge switch and the crowbar pseudospark switch were investigated. By monitoring the preset applied capacitor voltage, the gap distance of the main discharging switch could be adjusted to ensure a discharging delay time less than 2 μs. Equipped with a surface flashover trigger device made of high relative perimittivity dielectric material BaTiO3 (εr = 3460), the discharge delay time of the crowbar pseudospark switch is less than 85 ns, and the minimum operating voltage is less than 1% of its self-breakdown voltage. With a storage capacitor of 9 μF , an inductor of 18 μH and a crowbar pseudospark switch, a load of 30 mΩ and an applied capacitor voltage of 40 kV, an impulse current wave form of maximum 25 kA was generated with a rise time and time to half peak value of 17.2/μs and 336 μs respectively.

  11. 软开关脉宽调制变频技术%Soft-Switching Technique in Pulse Width Modulation Inverters

    Institute of Scientific and Technical Information of China (English)

    陈国呈; 谷口胜则; 中村博人

    2000-01-01

    In this paper, a new soft-switching inverter using a minimum number of devices, and a new PWM (pulse-width modulation)method suitable for 3-phase soft-switching inverters are proposed. The circuit is used as an interface between the DC supply and the conventional voltage source of a PWM inverter. The number of switching operations can be reduced by using the PWM strategy. Increasing the amplitude of the fundamental component contained in the output waveform results in an effective utilization of the DC supply, a reduction of nominated capacity of the inverter elements, and a reduction of switching loss in the switching devices.

  12. MW-scale ICRF plasma heating using IGBT switches in a multi-pulse scheme

    Science.gov (United States)

    Be'ery, I.; Kogan, K.; Seemann, O.

    2015-06-01

    Solid-state silicon switches are cheap and reliable option for 1-10 MHz RF power sources, required for plasma ion cyclotron RF heating (ICRF). The large `on' resistance of MOSFET and similar devices limits their power delivery to a few tens of kW per switch. Low resistivity devices, such as IGBT, suffer from large `off' switching time, which limits their useful frequency range and increases the power dissipated in the switch. Here we demonstrate more than 0.8 MW circulated RF power at 2 MHz using only three high voltage IGBT switches. The circuit uses the fast `on' switching capability of the IGBTs to generate high-Q pulse train. This operation mode also simplifies the measurement of RF coupling between the antenna and the plasma.

  13. Photonic-crystal switch divider based on Ge2Sb2Te5 thin films.

    Science.gov (United States)

    Ma, Beijiao; Zhang, Peiqing; Wang, Hui; Zhang, Tengyu; Zeng, Jianghui; Zhang, Qian; Wang, Guoxiang; Xu, Peipeng; Zhang, Wei; Dai, Shixun

    2016-11-10

    A three-port phase-change photonic-crystal switch divider based on Ge2Sb2Te5 chalcogenide thin film was proposed. The chalcogenide material used was determined to have a high refractive index and fast phase-change speed by using laser radiation. The structure with a T-junction cavity was used to achieve three switch functions: switching "ON" in only one output port, switching "OFF" in both output ports, and dividing signals into two output ports. The transmission properties of the designed device at 2.0 μm were studied by the finite difference time domain method, which showed that the switch divider can achieve very high switching efficiency by optimizing T-junction cavity parameters. The scaling laws of photonic crystals revealed that the operating wavelength of the designed structure can be easily extended to another wavelength in the midinfrared region.

  14. The bistability phenomenon in single and coupled oscillators based on VO2 switches

    Science.gov (United States)

    Belyaev, M. A.; Putrolaynen, V. V.; Velichko, A. A.

    2017-01-01

    New operation regimes of single and coupled oscillators in circuits based on planar VO2 switches have been studied. The phenomenon of bistability is discovered, which consists in controlled switching of self-sustained oscillations by external pulses, which is a promising basis for the creation of oscillatory memory cells and implementation of pulse coupling regimes in artificial neural networks (ANNs). The duration of switch-on and switch-off pulses is no less that 20 μs and 30 ms, respectively. It is established that the region of threshold voltages for bistable switching in coupled oscillators is much wider than in a single oscillator and the hysteresis width in the former case can reach 2 V. A regime of initiation of switching packets has been observed that models the ANN packet activity.

  15. Left Coronary Artery-Pulmonary Artery Fistula in Coronary Artery Disease

    Directory of Open Access Journals (Sweden)

    Orhan Veli Doğan

    2012-08-01

    Full Text Available Coroner artery fistula which is rare and congenital or acquired arise from whole coroner artery drainage all of cardiac chamber and great artery. Although coroner artery fistula is uncommon, it can cause significant mortality and morbidity rates. The article is presented which coroner artery disease and coroner-pulmonary artery fistula was accomplishment committed. Sixty three year-old male patient admitted to the hospital with chest pain. Non-ST myocardial infarction was diagnosed in the examinations. After coroner angiography, it was found coronary artery disease in addition between LAD proximal portion and main pulmonary artery fistula. Fistula repair and coronary bypass were performed successfully under cardiopulmonary bypass. Without hemodynamic problem in intensive care and service follow-up, the patient was discharged from the hospital in the seventh postoperative day. We think that surgical treatment of coronary fistulas in patients with coronary artery lesion is done at the earliest time would enable improvement in mortality and morbidity rates.

  16. Early results of coronary artery bypass grafting with coronary endarterectomy for severe coronary artery disease

    Directory of Open Access Journals (Sweden)

    Toischer Karl

    2009-09-01

    Full Text Available Abstract Background Despite the existence of controversial debates on the efficiency of coronary endarterectomy (CE, it is still used as an adjunct to coronary artery bypass grafting (CABG. This is particularly true in patients with endstage coronary artery disease. Given the improvements in cardiac surgery and postoperative care, as well as the rising number of elderly patient with numerous co-morbidities, re-evaluating the pros and cons of this technique is needed. Methods Patient demographic information, operative details and outcome data of 104 patients with diffuse calcified coronary artery disease were retrospectively analyzed with respect to functional capacity (NYHA, angina pectoris (CCS and mortality. Actuarial survival was reported using a Kaplan-Meyer analysis. Results Between August 2001 and March 2005, 104 patients underwent coronary artery bypass grafting (CABG with adjunctive coronary endarterectomy (CE in the Department of Thoracic-, Cardiac- and Vascular Surgery, University of Goettingen. Four patients were lost during follow-up. Data were gained from 88 male and 12 female patients; mean age was 65.5 ± 9 years. A total of 396 vessels were bypassed (4 ± 0.9 vessels per patient. In 98% left internal thoracic artery (LITA was used as arterial bypass graft and a total of 114 vessels were endarterectomized. CE was performed on right coronary artery (RCA (n = 55, on left anterior descending artery (LAD (n = 52 and circumflex artery (RCX (n = 7. Ninety-five patients suffered from 3-vessel-disease, 3 from 2-vessel- and 2 from 1-vessel-disease. Closed technique was used in 18%, open technique in 79% and in 3% a combination of both. The most frequent endarterectomized localization was right coronary artery (RCA = 55%. Despite the severity of endstage atherosclerosis, hospital mortality was only 5% (n = 5. During follow-up (24.5 ± 13.4 months, which is 96% complete (4 patients were lost caused by unknown address 8 patients died (cardiac

  17. Early results of coronary artery bypass grafting with coronary endarterectomy for severe coronary artery disease

    Science.gov (United States)

    Schmitto, Jan D; Kolat, Philipp; Ortmann, Philipp; Popov, Aron F; Coskun, Kasim O; Friedrich, Martin; Sossalla, Samuel; Toischer, Karl; Mokashi, Suyog A; Tirilomis, Theodor; Baryalei, Mersa M; Schoendube, Friedrich A

    2009-01-01

    Background Despite the existence of controversial debates on the efficiency of coronary endarterectomy (CE), it is still used as an adjunct to coronary artery bypass grafting (CABG). This is particularly true in patients with endstage coronary artery disease. Given the improvements in cardiac surgery and postoperative care, as well as the rising number of elderly patient with numerous co-morbidities, re-evaluating the pros and cons of this technique is needed. Methods Patient demographic information, operative details and outcome data of 104 patients with diffuse calcified coronary artery disease were retrospectively analyzed with respect to functional capacity (NYHA), angina pectoris (CCS) and mortality. Actuarial survival was reported using a Kaplan-Meyer analysis. Results Between August 2001 and March 2005, 104 patients underwent coronary artery bypass grafting (CABG) with adjunctive coronary endarterectomy (CE) in the Department of Thoracic-, Cardiac- and Vascular Surgery, University of Goettingen. Four patients were lost during follow-up. Data were gained from 88 male and 12 female patients; mean age was 65.5 ± 9 years. A total of 396 vessels were bypassed (4 ± 0.9 vessels per patient). In 98% left internal thoracic artery (LITA) was used as arterial bypass graft and a total of 114 vessels were endarterectomized. CE was performed on right coronary artery (RCA) (n = 55), on left anterior descending artery (LAD) (n = 52) and circumflex artery (RCX) (n = 7). Ninety-five patients suffered from 3-vessel-disease, 3 from 2-vessel- and 2 from 1-vessel-disease. Closed technique was used in 18%, open technique in 79% and in 3% a combination of both. The most frequent endarterectomized localization was right coronary artery (RCA = 55%). Despite the severity of endstage atherosclerosis, hospital mortality was only 5% (n = 5). During follow-up (24.5 ± 13.4 months), which is 96% complete (4 patients were lost caused by unknown address) 8 patients died (cardiac failure: 3

  18. Right iliac arterial aneurysm in a 4-year-old girl who does not have a right external iliac artery.

    Science.gov (United States)

    Lee, Jeong-Hwan; Oh, Chaeyoun; Youn, Joong Kee; Han, Ji-Won; Kim, Hyun-Young; Jung, Sung-Eun

    2016-11-01

    Pediatric arterial aneurysm is rare disease. Among them, idiopathic-congenital arterial aneurysm is extremely rare. This is a case report of right common iliac artery idiopathic aneurysm with absence of right external iliac artery. A 4-year-old girl who had been complaining of intermittent abdominal pain since 2 years prior presented with a right lower abdominal mass that had been palpable since 6 months prior. Abdominal CT revealed a 5.2 cm × 4.5 cm × 5.1 cm, right-sided, partially thrombosed, saccular, iliac artery aneurysm. She underwent to operation, aneurismal resection. A pathological examination confirmed that it was a true aneurysm, considering that all layers of the vascular wall were stretched with no deficit. The patient was discharged 3 days after the surgery without any complication. Five months passed since the surgery, and the patient is doing well without any abdominal or leg pain.

  19. Arterial hypertension and cancer.

    Science.gov (United States)

    Milan, Alberto; Puglisi, Elisabetta; Ferrari, Laura; Bruno, Giulia; Losano, Isabel; Veglio, Franco

    2014-05-15

    Arterial hypertension and cancer are two of the most important causes of mortality in the world; correlations between these two clinical entities are complex and various. Cancer therapy using old (e.g., mitotic spindle poisons) as well as new (e.g., monoclonal antibody) drugs may cause arterial hypertension through different mechanisms; sometimes the increase of blood pressure levels may be responsible for chemotherapy withdrawal. Among newer cancer therapies, drugs interacting with the VEGF (vascular endothelial growth factors) pathways are the most frequently involved in hypertension development. However, many retrospective studies have suggested a relationship between antihypertensive treatment and risk of cancer, raising vast public concern. The purposes of this brief review have then been to analyse the role of chemotherapy in the pathogenesis of hypertension, to summarize the general rules of arterial hypertension management in this field and finally to evaluate the effects of antihypertensive therapy on cancer disease.

  20. Quadratic stabilization of switched nonlinear systems

    Institute of Scientific and Technical Information of China (English)

    DONG YaLi; FAN JiaoJiao; MEI ShengWei

    2009-01-01

    In this paper, the problem of quadratic stabilization of multi-input multi-output switched nonlinear systems under an arbitrary switching law is investigated. When switched nonlinear systems have uniform normal form and the zero dynamics of uniform normal form is asymptotically stable under an arbitrary switching law, state feedbacks are designed and a common quadratic Lyapunov function of all the closed-loop subsystems is constructed to realize quadratic stabilizability of the class of switched nonlinear systems under an arbitrary switching law. The results of this paper are also applied to switched linear systems.