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Sample records for arterial switch operation

  1. Main pulmonary artery area limits exercise capacity in patients long-term after arterial switch operation

    NARCIS (Netherlands)

    Baggen, Vivan J M; Driessen, Mieke M P; Meijboom, Folkert J; Sieswerda, Gertjan Tj; Jansen, Nicolaas J G; van Wijk, Sebastiaan W H; Doevendans, Pieter A; Leiner, Tim; Schoof, Paul H; Takken, Tim; Breur, Johannes M P J

    2015-01-01

    OBJECTIVES: Despite excellent survival in patients after the arterial switch operation, reintervention is frequently required and exercise capacity is decreased in a substantial number of patients. This study relates right-sided imaging features in patients long-term after the arterial switch operat

  2. Coronary artery occlusion after arterial switch operation in an asymptomatic 15-year-old boy.

    Science.gov (United States)

    Saini, Ashish P; Cyran, Stephen E; Ettinger, Steven M; Pauliks, Linda B

    2016-08-16

    A 15-year-old boy with transposition of the great arteries (TGA) and neonatal arterial switch operation (ASO) presented with complete occlusion of the left main coronary artery (LMCA). Intra-operatively, an intramural left coronary artery was identified. Therefore, since age 7 years he had a series of screening exercise stress tests. At 13 years old, he had 3 to 4 mm ST segment depression in the infero-lateral leads without symptoms. This progressed to 4.2 mm inferior ST segment depression at 15 years old with normal stress echocardiogram. Sestamibi myocardial perfusion scan and cardiac magnetic resonance imaging was inconclusive. Therefore, a coronary angiogram was obtained which showed complete occlusion of the LMCA with ample collateralization from the right coronary artery system. This was later confirmed on a computed tomogram (CT) angiogram, obtained in preparation of coronary artery bypass grafting. The case illustrates the difficulty of detecting coronary artery stenosis and occlusion in young patients with rich collateralization. Coronary CT angiogram and conventional angiography were the best imaging modalities to detect coronary anomalies in this adolescent with surgically corrected TGA. Screening CT angiography may be warranted for TGA patients, particularly for those with known coronary anomalies. PMID:27574609

  3. Coronary artery occlusion after arterial switch operation in an asymptomatic 15-year-old boy

    Science.gov (United States)

    Saini, Ashish P; Cyran, Stephen E; Ettinger, Steven M; Pauliks, Linda B

    2016-01-01

    A 15-year-old boy with transposition of the great arteries (TGA) and neonatal arterial switch operation (ASO) presented with complete occlusion of the left main coronary artery (LMCA). Intra-operatively, an intramural left coronary artery was identified. Therefore, since age 7 years he had a series of screening exercise stress tests. At 13 years old, he had 3 to 4 mm ST segment depression in the infero-lateral leads without symptoms. This progressed to 4.2 mm inferior ST segment depression at 15 years old with normal stress echocardiogram. Sestamibi myocardial perfusion scan and cardiac magnetic resonance imaging was inconclusive. Therefore, a coronary angiogram was obtained which showed complete occlusion of the LMCA with ample collateralization from the right coronary artery system. This was later confirmed on a computed tomogram (CT) angiogram, obtained in preparation of coronary artery bypass grafting. The case illustrates the difficulty of detecting coronary artery stenosis and occlusion in young patients with rich collateralization. Coronary CT angiogram and conventional angiography were the best imaging modalities to detect coronary anomalies in this adolescent with surgically corrected TGA. Screening CT angiography may be warranted for TGA patients, particularly for those with known coronary anomalies. PMID:27574609

  4. ARTERIAL SWITCH OPERATION FOR COMPLETE D-TRANSPOSITION OF THE GREAT ARTERIES:SURGICAL RESULTS AND ANALYSIS

    Institute of Scientific and Technical Information of China (English)

    XU Zhi-wei; DU Xin-wei; SU Zhao-kang; DING Wen-xiang

    2008-01-01

    Objective To review and analyze the surgical results of arterial switch operations in complete D-transposition of the great arteries (TGA ). Methods A total of 113 patients underwent arterial switch operation from Jan. 2001 to Dec. 2005. There were 60 patients with transposition of the great arteries and intact ventricular septum (TGA/IVS) and 53 patients with transposition of the great arteries and ventricular septal defect (TGA/VSD). The lowest body weight was 2.3 kg and the smallest age was 6 h. The arterial switch operation was performed under deep hypothermia with circulatory arrest and low-flow perfusion. Results The total mortality was 9.73%. There were 5 deaths in TGA/IVS (8.3%), 6 deaths in TGA/VSD (11.3%). With the development of surgical technique, peri-operative management and cardiopulmonary bypass, the total mortality significantly decreased from 16.65% in the early times to 5.5% lately. Conclusion The vital risk of the operation is coronary artery malformation. The incidence of coronary artery malformation is higher in TGA/VSD than in TGA/ IVS. The positional relationship of the great arteries does not affect the results of the operation. The arterial switch operation should be prevented when the pressure ratio between the left and right ventricle is less than 0.6, otherwise it is great likely to cause severe low cardiac output postoperatively.

  5. Evaluation of Electrocardiographic Changes after Arterial Switch Operation

    Directory of Open Access Journals (Sweden)

    Hamid Amoozgar

    2014-09-01

    Full Text Available Background: Transposition of Great Arteries (TGA is a serious congenital heart disease which can be accompanied by good outcomes with anatomic correction within the first few weeks of life. Objectives: The present study aimed to evaluate electrocardiographic changes in the children with uncomplicated Arterial Switch Operation (ASO. Patients and Methods: Twelve lead electrocardiograms were obtained from thirty-three patients with TGA after ASO. Then, the patients’ QT-dispersion and P-wave dispersion were compared to those of 33 age- and gender-matched individuals as the normal control group. Both groups were also evaluated by M-mode echocardiography. Student’s t-test and Pearson correlation were used to analyze the data. Besides, P < 0.05 was considered as statistically significant. Results: The mean age of the patients and the control group was 41 ± 3.7 and 40.12 ± 4.2 months, respectively. Comparison of P wave, T wave, QRS complex, PR interval, QT segment, and corrected QT segment showed significant differences in the frequency of inverted T wave in pericardial leads [V3, V4, V5, and V6] (P = 0.004; more in patients, P wave amplitude in lead II (P < 0.001; more in patients, R wave amplitude in V1 (P = 0.016; smaller in patients, R and S waves amplitude in V6 (P = 0.004 and P = 0.001; taller in patients, corrected QT segment (in lead V5; P < 0.0001: prolonger in patients, and PR interval (P = 0.001; prolonger in patients. However, no significant differences were found regarding the vector axis and heart rate. Right bundle branch block (18% vs. 0%, Bifascicular (3% vs. 0%, and first-degree blocks (15% vs. 0% were significantly more in the patients. Besides, the PR interval was longer in the corrected complex TGA (146 ± 24.4 vs. 127.7 ± 23.1, P = 0.001. Moreover, R/S ratio in lead V1 was significantly prolonger, among the patients (2.86 ± 3.35 vs. 0.706 ± 0.53, P = 0.002. Nonetheless, no significant was observed between the patients and

  6. The arterial switch operation in Europe for transposition of the great arteries : A multi-institutional study from the European Congenital Heart Surgeons Association

    NARCIS (Netherlands)

    Sarris, George E.; Chatzis, Andrew C.; Giannopoulos, Nicolas M.; Kirvassilis, George; Berggren, Hakan; Hazekamp, Mark; Carrel, Thierry; Comas, Juan V.; Di Carlo, Duccio; Daenen, Willem; Ebels, Tjark; Fragata, Jose; Hraska, Victor; Ilyin, Vladimir; Lindberg, Harald L.; Metras, Dominique; Pozzi, Marco; Rubay, Jean; Sairanen, Heikki; Stellin, Giovanni; Urban, Andreas; Van Doorn, Carin; Ziemer, Gerhard

    2006-01-01

    Objectives: This study analyzes the results of the arterial switch operation for transposition of the great arteries in member institutions of the European Congenital Heart Surgeons Association. Methods: The records of 613 patients who underwent primary arterial switch operations in each of 19 parti

  7. Two-stage arterial switch operation: is late ever too late?

    Science.gov (United States)

    Al Qethamy, Howaida O; Aizaz, Khawar; Aboelnazar, Saber A R; Hijab, Samina; Al Faraidi, Yahya

    2002-09-01

    Results of the two-stage arterial switch operation in 49 patients with transposition of the great arteries, performed between January 1995 and September 2000, were reviewed retrospectively. Twenty-one patients had a ventricular septal defect. Anatomical correction was carried out 21.89 +/- 9.86 months after pulmonary artery banding, with or without a modified Blalock-Taussig shunt. Hospital mortality was 8% (4 patients). During follow-up of 30.12 +/- 14.38 months, there was 1 late death and 1 patient required reoperation for pseudoaneurysm of the ascending aorta. Actuarial survival and freedom from reoperation at 5 years were 90% and 97%, respectively. Late anatomic correction (> 6 months) after the preliminary procedure can be performed with an acceptable mortality and morbidity, but undue delay may lead to left ventricular dysfunction, arrhythmias, and new aortic valve regurgitation or subaortic stenosis. PMID:12213747

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

    International Nuclear Information System (INIS)

    The neonatal arterial switch operation (ASO) is now the standard of care for children born with transposition of the great arteries. Stenosis of the neopulmonary artery on long-term follow up is a known complication. We performed a retrospective analysis of eleven patients who underwent a cardiac magnetic resonance imaging (MRI) due to echocardiographic evidence suggestive of stenosis of the neopulmonary artery or its branches (mean estimated Doppler gradient 48 mmHg, min 30 mmHg, max 70 mmHg). A comprehensive evaluation of anatomy and perfusion was done by cardiac MRI. The branches of the neopulmonary artery (neo PA) showed decreased caliber in three patients unilaterally and in two patients, bilaterally. Magnetic resonance (MR) perfusion studies showed concomitant decreased flow, with discrepancy between the two lungs of 35/65% or worse, only in the three patients with unilateral obstruction, by two different MR perfusion methods. 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

  9. Preoperative Intubation and Lack of Enteral Nutrition are Associated with Prolonged Stay After Arterial Switch Operation.

    Science.gov (United States)

    Iliopoulos, Ilias; Burke, Redmond; Hannan, Robert; Bolivar, Juan; Cooper, David S; Zafar, Farhan; Rossi, Anthony

    2016-08-01

    Mortality for the arterial switch operation (ASO) has diminished significantly over the past few decades. Some patients do, however, continue to have protracted and complicated courses after surgery. We attempted to determine which preoperative factors were best associated with prolonged hospital stay after ASO. We retrospectively reviewed all patients that underwent an ASO over a 10-year period. Outcomes of patients with postoperative stays (POS) >14 days (long stay group-LS) were compared with those patients with POS management the day prior to surgery including use of prostaglandin E1 (PGE1), inotropes, intubation status and the establishment of enteral feeds. The SS group had 25 patients and the LS group had 32 patients. Both groups (SS vs. LS) were similar in PGE1 use (48 vs. 69 %), BAS (76 vs. 59 %), age at surgery (6 vs. 7 days) and preoperative inotropes (12 vs. 38 %). The SS group had significantly higher incidence of preoperative feeding (80 vs. 31 %, p operating on patients with worse preoperative hemodynamics or a consequence of a preoperative management strategy that did not allow for extubation and establishment of feeds prior to surgery. PMID:27084382

  10. 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

  11. 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.

  12. 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.

  13. 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)

  14. 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.

  15. Langzeitverlauf des kardiologischen Gesundheitszustandes nach neonataler arterieller Switch-Operation

    OpenAIRE

    Schulze, Annika

    2010-01-01

    The neonatal arterial switch operation (ASO), has been introduced in the mid-1980s, as the first line surgical procedure for the transposition of the great arteries with or without atrial septum defect. Between March 1986 and February 1992, 96 consecutive newborns with TGA underwent the ASO in our institution. In this monocentric prospective longitudinal study we evaluated the long term cardiological and general health status as well as the exercise capacity of a homogenous group of adolescen...

  16. The Concept of the Arch Window in the Spiral Switch of the Great Arteries.

    Science.gov (United States)

    Chiu, Ing-Sh; Lee, Meng-Luen; Huang, Shu-Chien; Chang, Chung-I; Chen, Yih-Sharng; Wu, Mei-Hwan; Anderson, Robert H

    2016-08-01

    When the arterial switch operation includes the Lecompte maneuver, the arterial trunks are reconnected in parallel, rather than the spiral fashion observed in the normal heart. Thus, although the ventriculo-arterial connections are hemodynamically corrected, the anatomic arrangement cannot be considered normal. We hypothesized that, if feasible, it would be advantageous to restore a spiral configuration for the arterial trunks. In 58 patients, we reconstructed the arterial trunks such that, postoperatively, the pulmonary channel spirals round the aorta, passing to either the right or the left, and branches posteriorly. We compared the outcomes with those in 95 patients undergoing a standard non-spiraling operation over the same period. Average follow-up was 8.2 ± 4.5 years. The estimated 10-year survival was similar in the cohorts, at 94.7 % for those with spiraling trunks, as compared to 90.4 % for those with parallel outflow tracts. Reoperation-free survival at 10 years was not significantly different (87.6 vs. 90.5 %). Supravalvar pulmonary stenosis, aortic neo-coarctation, or left bronchial stenosis, however, was encountered in one-eighth of those undergoing a standard operation. None of these complications occurred in those patients who, postoperatively, had spiraling outflow tracts (P = 0.002). Reconstruction of spiraling trunks after the arterial switch has, thus far, avoided the complications of supravalvar pulmonary stenosis, neo-aortic kinking, or bronchial stenosis. The spiraling arrangement prevents compression of the pulmonary vessels and bronchial tree by the aorta, since it provides a wide window in the new aortic arch. PMID:27272691

  17. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Science.gov (United States)

    ROBOT-ASSISTED MINIMALLY INVASIVE CORONARY ARTERY BYPASS SURGERY OPERATION PINNACLEHEALTH HARRISBURG HOSPITAL HARRISBURG, PA 00:00:08 ... Hospital campus. We are going to witness a robot-assisted minimally invasive coronary artery bypass surgery operation. ...

  18. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ROBOT-ASSISTED MINIMALLY INVASIVE CORONARY ARTERY BYPASS SURGERY OPERATION PINNACLEHEALTH HARRISBURG HOSPITAL HARRISBURG, PA 00:00:08 ... Hospital campus. We are going to witness a robot-assisted minimally invasive coronary artery bypass surgery operation. ...

  19. 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.

  20. 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.

  1. Cryogenic operation of emitter switched thyristor structures

    Science.gov (United States)

    Flores, D.; Jordà, X.; Vellvehí, M.; Rebollo, J.; Millán, J.

    1999-03-01

    This paper analyses the effect of decreasing the operating temperature on the electrical characteristics of 1100 V epitaxial EST structures. Detailed performed static and transient measurements on ceramic packaged devices at 77 K have shown a significant increase of the maximum controllable current density and a notable reduction of the transient losses and the turn-off time. A reduction of the on-state voltage drop with temperature is observed at current density values higher than 80 A/cm 2 (positive coefficient), leading to a more uniform turn-off process. Furthermore, a model is provided to include the temperature effect on the latching current of the main and parasitic thyristor, transconductance and dynamic parameters.

  2. 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

  3. Pseudo-spark switch (PSS) characteristics under different operation conditions

    Science.gov (United States)

    Hamad, B. H.; Lateef, K. H.; Ahmad, A. K.

    2016-08-01

    The present paper concentrates on the characteristics of the pseudospark switch (PSS) designed in a previous work. The special characteristics of PSS make it a replacement for other high voltage switches such as thyratrons and ordinary high-pressure spark gaps. PSS is characterized by short rise time and small jitter time. The pseudo park chamber consists of two hollow cylindrical electrodes made of a stainless steel material (type 306L) separated by an insulator. The insulator used in our design is a glazed ceramic 70 mm in diameter and 3.5 mm in thickness. A PSS with an anode voltage of 29.2 kV, and a current of 3.6 kA and 11 ns rise time was achieved and used successfully at a repetition rate of about 2.2 kHz. A simple trigger circuit designed, built, and used effectively reaching more than 1.56 kV trigger pulse which is sufficient to ignite the argon gas inside the cathode to cause a breakdown. A non-inductive dummy load is designed to be a new technique to find the accurate value of the PSS inductance. A jitter time of ±10 ns pulses is observed to occur in a reliable manner for more than 6 h of continuous operation. In this research, the important parameters of this switch like rise time, peak current, and anode voltage were studied at various values of charging capacitance. The lifetime of this system is depending on the kind of the electrode material and on the type of insulation material in the main gap of the pseudospark switch.

  4. Experience of Pseudospark Switch Operation in Pulse Power Applications

    OpenAIRE

    Voitenko, Nikita Valerievich; Yudin, Artem Sergeevich; Kuznetsova, Nataliya Sergeevna; Bochkov, V. D.

    2015-01-01

    The paper demonstrates the results of TDI1-200k/25SN-P pseudospark switch (PSS) developed by Russian company "Pulsed Technologies Ltd" application. PSS was used in pulsed power unit intended for electric-discharge fracture of rocks and concrete blocks and splitting off from monolith. The pulsed power unit has a pulse current generator with the capacity of 560 [mu]F, stored energy of up to 63 kJ, operating voltage of up to15 kV, current pulse amplitude of up to 200 kA and pulse duration more t...

  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. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ... PINNACLEHEALTH HARRISBURG HOSPITAL HARRISBURG, PA 00:00:08 JOHN PENNOCK, MD: Welcome this evening to PinnacleHealth Harrisburg ... artery bypass surgery operation. My name is Dr. John Pennock. I'm going to introduce you shortly ...

  7. 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.

  8. Operation and endurance of reed switches at high temperatures and pressures

    International Nuclear Information System (INIS)

    We are developing a reed switch based thermocouple multiplexer for use inside gas cooled nuclear reactors. Experiments have been carried out to determine the feasibility of operating reed switches at typical temperatures and pressures found in operating AGR's. The survivability of reed switches under reactor transient temperature conditions has also been assessed. The emphasis has been on measuring the variation of the pull-in and drop-out field characteristics of the reed switches. (author)

  9. 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.

  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. Development of a differential pressure switch for precise operation under negative pressure

    International Nuclear Information System (INIS)

    Negative atmospheric pressure is an isolation technique used in nuclear facilities including vessels and hot-cells to prevent release of radioactive materials. In the related system, differential pressure switches are very important function for process monitoring such as liquid level and negative pressure in a reprocessing process. Although air-tight switches have been using to avoid radioactive contamination, such type of switch have not meet requirements for precise operation under deep negative pressure. Therefore, we have been investigation an improved types of switches to overcome the problem. We have developed a prototype switch and made some vibration and endurance tests. Their results are described in this paper. (author)

  13. Influences of Switching Jitter on the Operational Performances of Linear Transformer Drivers-Based Drivers

    Institute of Scientific and Technical Information of China (English)

    刘鹏; 孙凤举; 魏浩; 王志国; 尹佳辉; 邱爱慈

    2012-01-01

    A whole circuit model of a linear transformer drivers (LTD) module composed of 60 cavities in series was developed in the software PSPICE to study the influence of switching jitter on the operational performances of LTDs. In the model, each brick in each cavity is capable of operating with jitter in its switch. Additionally, the manner of triggering cables entering into cavities was considered. The performances of the LTD module operating with three typical cavity-triggering sequences were simulated and the simulation results indicate that switching jitter affects slightly the peak and starting time of the output current pulse. However, the enhancement in switching jitter would significantly lengthen the rise time of the output current pulse. Without considering other factors, a jitter lower than 10 ns may be necessary for the switches in the LTD module to provide output current parameters with an acceptable deviation.

  14. 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

  15. Hanging foot switch for bipolar forceps: a device for surgeons operating in the standing position: technical note.

    Science.gov (United States)

    Shimizu, Satoru; Kondo, Koji; Yamazaki, Tomoya; Koizumi, Hiroyuki; Miyazaki, Tomoko; Osawa, Shigeyuki; Sagiuchi, Takao; Nakayama, Kenji; Yamamoto, Isao; Fujii, Kiyotaka

    2013-01-01

    For surgeons operating in the standing position, the manipulation of foot switches involves shifting of the weight to the pivoting leg and the possible loss of contact between the switch and the foot. We solved this problem by changing the position of the switch that operates bipolar forceps. Our novel device is made of aluminum plates. The base plate features a foot strap and a height-adjustable overhang over the switch-operating foot. A commercially-available disc type foot switch is attached to the underside of the overhang in upside-down position, so the switch is operable with the toe. To turn on the switch, the toe is flexed dorsally to push the switch pedal, so the action is limited to the part distal to the metatarsophalangeal joints. Our switch was used in more than 100 consecutive microsurgeries performed by surgeons operating in the standing position. The switch manipulation required no shifting of the weight and was easier and quicker than manipulation of conventionally-placed switches. The surgeons were able to change the foot position freely with the modified switch, thereby avoiding loss of contact with the switch. The modified switch placement reduced physical fatigue in the lower extremities, annoyance related to the manipulation of conventionally-placed switches, and increased the comfort of surgeons operating in the standing position. PMID:23358172

  16. 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....

  17. 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

    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......-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....... Moreover, the analysis can be applied to other types of resonant converters with or without piezoelectric transformers. Experimental and simulation results are provided, verifying the performed analysis....

  18. 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.

  19. 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...

  20. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ... distributing blood supply to. He the went for heart catheterization, which revealed him to have 100 percent ... the artery on the front surface of the heart. And his left anterior descending, which is really ...

  1. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ... 59:44 CHRIS MCCARTY, MD: Yeah. Okay. Thankfully technology keeps working with us, so we have this ... artery. Now we're going to use new technology that we were one of the first to ...

  2. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ... Harrisburg Hospital campus. We are going to witness a robot-assisted minimally invasive coronary artery bypass surgery ... you're starting to do and maybe give a little background on the patient's condition? 00:00: ...

  3. 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.

  4. Non-operative management of arterial liver hemorrhages

    International Nuclear Information System (INIS)

    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.)

  5. 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.

  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. 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.

  8. Towards self-healing in distribution networks operation: Bipartite graph modelling for automated switching

    Energy Technology Data Exchange (ETDEWEB)

    Kost' alova, Alena; Carvalho, Pedro M.S. [Department of Electrical Engineering and Computers, Instituto Superior Tecnico, UTL, Av. Rovisco Pais, Lisbon (Portugal)

    2011-01-15

    The concept of self-healing has been recently introduced in power systems. The general self-healing framework is complex and includes several aspects of networks' operation. This paper deals with automated switching in the context of autonomous operation of distribution networks. The paper presents a new network data model that allows effective reconfiguration algorithms to be designed. The model is based on bipartite graph representation of switching possibilities. The model properties and capabilities are illustrated for simple self-healing algorithms and a small real world medium voltage distribution network. (author)

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Electromagnetic Field Emission From Gas-to-Air Bushing in a GIS During Switching Operations

    OpenAIRE

    Rao, Mohana M; Thomas, Joy M; Singh, BP

    2007-01-01

    Very fast transient overvoltages (VFTOs) and the associated very fast transient currents (VFTCs) generated during switching operations in a gas-insulated substation (GIS) radiate electromagnetic (EM) fields, which in turn can leak into the external environment through apertures like $SF_6$ gas-to-air bushing. Therefore, it becomes necessary to characterize and quantify the EM fields when sensitive control devices are used for the operation of such substations. Keeping this in view, a numerica...

  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. NbTi foil thermally controlled switches for superconducting converters with operation frequency up to 50 Hz. Part 1: Experiment

    NARCIS (Netherlands)

    Shevchenko, O.A.; Mulder, G.B.J.; Markovsky, N.V.; Kate, ten H.H.J.

    1992-01-01

    The increase of the operation frequency of superconducting converters up to 50 Hz opens new ways to improve their parameters. Thermally controlled switches using NbTi foil are able to operate at industrial frequency with reasonable efficiency and dynamic parameters. Such switches have been developed

  16. Near field coupling to shielded cable due to switching operation in substation

    Institute of Scientific and Technical Information of China (English)

    Lei QI; Xiang CUI

    2008-01-01

    It is vital to study the electromagnetic coupling to shielded cable for improving electromagnetic antiinterference ability of secondary equipment in a substation.As a hybrid of method of moment (MoM) and transmission line method,a frequency domain model is put forward to study the near field coupling to shielded cable due to the switching operation in substation.Compared with the results Of EMTP.the proposed method has been proven correct.Furthermore,this method overcomes the disadvantage of EMTP,which is only applicable for transient analysis of parallel conductors.As an example,the presented method is applied to evaluating the electromag netic interference(EMI)to the shielded cable,whose shield is grounded at both ends,due to the switching operation in 500 kV air insulation substation (AIS).

  17. 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

  18. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ... shortly to Dr. Chris McCarty, who's in the operating room and has started the procedure. This procedure ... the procedure. So we'll go into the operating room to see Dr. McCarty. Hello Chris. 00: ...

  19. 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.

  20. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ... surgery operation. My name is Dr. John Pennock. I'm going to introduce you shortly to Dr. ... a large incision that would be made and I have a line drawn across here, just for ...

  1. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ... with one other small incision up by the shoulder. So, what they're going to start doing ... Post-operatively, this patient will have very little pain. He'll be able to breathe better than ...

  2. 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.

  3. 49 CFR 1242.67 - Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Switch crews; controlling operations; yard and...; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive power... distribution of freight and passenger yard-switching hours in those yards common to both freight and...

  4. 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.

  5. Robot-Assisted Minimally Invasive Coronary Artery Bypass Surgery Operation

    Medline Plus

    Full Text Available ... say about it. 00:27:56 PATIENT ON VIDEO: The discussion I had on how the operation – ... recovery was remarkable. 00:29:17 PATIENT ON VIDEO: So, my recovery time was – I'm still ...

  6. [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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 40-GHz operation of a single-flux-quantum (SFQ) 4 x 4 switch scheduler

    International Nuclear Information System (INIS)

    We designed a single-flux-quantum (SFQ) scheduler for a 4 x 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

  12. 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...

  13. Assessment of the mechanical properties of peripheral arteries in chain saw operators using a photosensor.

    Science.gov (United States)

    Nakamura, H; Nakamura, H; Nagase, H; Miyoshi, T

    1994-01-01

    In order to evaluate the severity of peripheral vascular disorders, and to detect changes in the digital arteries of workers who use chain saws, the mechanical properties of the digital arteries of 22 such workers were examined using a photosensor. The elastic properties and the nonlinearity of digital arteries were assessed through observation of the changes in the vascular volume ratio (V/Vo) against the volume (Vo) at mean blood pressure (Pm). A significant negative correlation was found between age and V/Vo at a transmural pressure of 30 mmHg (V30/Vo), which suggested that V30/Vo tended to decrease with aging. Although it was impossible to calculate V30/Vo for chain saw operators because of the vague changes in the volume pulse wave, this nonlinearity was more clearly observed through changes in the relative vascular volume (V/V40) along with a reduction in cuff pressure (Pc) to 40 mmHg below systolic blood pressure. A group of similarly aged healthy controls and three groups of workers with a different severity of vibration-induced white finger (VWF), i.e., no symptoms of VWF, mild VWF and severe VWF, were classified according to the changes in their V/V40 and the reduction in Pc. The results obtained in the present study suggest that the peripheral vascular disorders in workers using chain saws are due to the opening disturbance of the arteries with nonlinear changes in the peripheral artery, which is related to functional and organic abnormality of the arteries. PMID:7591851

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Changes in the cardiac muscle electric activity as a result of Coronary Artery Bypass Graft operation

    Science.gov (United States)

    Grajek, Magdalena; Krzyminiewski, Ryszard; Kalawski, Ryszard; Kulczak, Mariusz

    2008-01-01

    Many bioelectric signals have a complex internal structure that can be a rich source of information on the tissue or cell processes. The structure of such signals can be analysed in detail by applying digital methods of signal processing. Therefore, of substantial use in diagnosis of the coronary arterial disease is the method of digital enhancement of increasing signal resolution ECG (NURSE-ECG), permitting detection of temporary changes in the electric potentials in the cardiac muscle in the process of depolarisation. Thanks to the application of NURSE-ECG it has become possible to detect relatively small changes in the electric activity of particular fragments of the cardiac muscle undetectable by the standard ECG method, caused by ischemia, the effect of a drug or infarct. The aim of this study was to identify and analyse changes in the electric activity of the cardiac muscle as a result of the Coronary Artery Bypass Graft (CABG) operation. In this study the method of NURSE-ECG has been applied in order to identify and analyse changes in the electric activity of the cardiac muscle as a result of the CABG operation. In the study performed in cooperation of the Institute of Physics Adam Mickiewicz University and the Strus Hospital, Cardiac Surgery Ward, 37 patients with advanced coronary arterial disease were asked to participate. The patients were examined prior to the operation, on the day after the operation and two months after the operation and a year after the operation. The ECG recordings were subjected to a numerical procedure of resolution enhancement by a NURSE-ECG program to reveal the tentative changes in the electric potential of the cardiac muscle on its depolarisation. Results of the study have shown that the NURSE ECG method can be applied to monitor changes in the electric activity of the cardiac muscle occurring as a result of CABG operation. One the second day after the operation in the majority of patients (70%) a rapid decrease of the total

  1. 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.

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

    OpenAIRE

    Garg Rajnish; Murthy Keshava; Rao Shekhar; John Colin

    2011-01-01

    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 c...

  3. Determination of the operating voltage for non-linear capacitors as turn-off snubbers in power electronic switches

    OpenAIRE

    A. G. K. Lutsch; J. J. Schoeman; J. D. van Wyk

    1988-01-01

    The use of non-linear capacitors improves the efficiency of turn-off snubbers for power electronic switches. The parameters for the determination of non-linear ferro-electric capacitors are discussed and a novel measuring method for the determination of the maximum operating voltage is suggested. The procedure to select ferro-electric capacitors is also discussed.

  4. Determination of the operating voltage for non-linear capacitors as turn-off snubbers in power electronic switches

    Directory of Open Access Journals (Sweden)

    A. G. K. Lutsch

    1988-03-01

    Full Text Available The use of non-linear capacitors improves the efficiency of turn-off snubbers for power electronic switches. The parameters for the determination of non-linear ferro-electric capacitors are discussed and a novel measuring method for the determination of the maximum operating voltage is suggested. The procedure to select ferro-electric capacitors is also discussed.

  5. 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...

  6. 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.

  7. High-Speed Operation of a Single-Flux-Quantum (SFQ) Cross/Bar Switch up to 35 GHz

    Science.gov (United States)

    Kameda, Yoshio; Yorozu, Shinichi; Terai, Hirotaka; Fujimaki, Akira

    2003-04-01

    Single-flux-quantum (SFQ) technology is a novel technology where binary information is represented by a single flux. It enables us to realize high-speed, low-power SFQ logic circuits, surpassing conventional complementary metal-oxide-silicon (CMOS) technology. We proposed an SFQ packet switch to avoid the bottlenecks in broadband networks of the future. To demonstrate high-speed operation of an SFQ logic circuit and its application to our switch architecture, we designed a cross/bar switch. It consists of 13 logic gates and 581 Josephson junctions were used in the layout. We confirmed correct operations up to 33 GHz in simulation. We placed the switch circuit in an on-chip test system for high-speed (over 10 GHz) test. Including I/O circuits, the system as a whole consists of 1236 Josephson junctions. The chip was fabricated by using NEC’s standard Nb process. We carried out an on-chip test and found correct operations up to 35 GHz.

  8. 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. PMID:27111150

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

    Science.gov (United States)

    Arheimer, Berit

    2014-05-01

    A recently started EU project (FP7 project No 603587) called SWITCH-ON will establish new infrastructure for water research in Europe. The overall goal of the project is to make use of open data, and add value to society by repurposing and refining data from various sources. SWITCH-ON will establish new forms of water research and facilitate the development of new products and services based on principles of sharing and community building. The basic for this work is a virtual water-science laboratory, which consists of open data, dedicated software tools and a set of protocols, hosted at the "SWITCH-ON water information" portal at http://water-switch-on.eu/. The laboratory will seamlessly integrate the open data with harmonised modelling tools and facilities the performance of virtual experiments of comparative science. Comparative science is a new form of research, which will advance science by contrasting water related processes in different environments and help understand complex processes in a more holistic way than individual studies The SWITCH-ON objectives are to use open data for implementing: 1) an innovative spatial information platform with open data tailored for direct water assessments, 2) an entirely new form of collaborative research for water-related sciences, 3) fourteen new operational products and services dedicated to appointed end-users, 4) new business and knowledge to inform individual and collective decisions in line with the Europe's smart growth and environmental objectives. The SWITCH-ON project will be one trigger in a contemporary global movement to better address environmental and societal challenges through openness and collaboration. The poster will present the project visions and achievements so far, and invite more research groups to use the virtual water-science laboratory.

  10. 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.

  11. Transients Induced on Control Cables and Secondary Circuit of Instrument Transformers in a GIS During Switching Operations

    OpenAIRE

    Rao, Mohana M; Thomas, Joy M; Singh, BP

    2007-01-01

    The transient fields generated during switching operations in gas-insulated substations (GIS) can have rise times in the order of a few nanoseconds. Transient fields, which are developed internally to the gas-insulated modules, leak into the external environment through discontinuities and interfere with nearby electronics. Depending on the configuration of the GIS and the observation point, amplitudes of the electric and magnetic fields could be of the order of a few tens of kilovolts per me...

  12. Nanoelectromechanical contact switches

    Science.gov (United States)

    Loh, Owen Y.; Espinosa, Horacio D.

    2012-05-01

    Nanoelectromechanical (NEM) switches are similar to conventional semiconductor switches in that they can be used as relays, transistors, logic devices and sensors. However, the operating principles of NEM switches and semiconductor switches are fundamentally different. These differences give NEM switches an advantage over semiconductor switches in some applications -- for example, NEM switches perform much better in extreme environments -- but semiconductor switches benefit from a much superior manufacturing infrastructure. Here we review the potential of NEM-switch technologies to complement or selectively replace conventional complementary metal-oxide semiconductor technology, and identify the challenges involved in the large-scale manufacture of a representative set of NEM-based devices.

  13. Plasma erosion opening switch in the double-pulse operation mode of a high-current electron accelerator

    International Nuclear Information System (INIS)

    This paper reports the results of investigations of the operation of a fast current opening switch, with a 10/sup 13/-10/sup 16/ plasma density produced either by dielectric surface flashover or by explosive emission of graphite. A series of two pulses was applied to two diodes in parallel. The first pulse produced plasma in the first diode which closed that diode gap by the arrival time of the second pulse. The first, shorted, diode then acted as an erosion switch for the second pulse. A factor of 2.5-3 power multiplication was obtained under optimum conditions. The opening-switch resistance during the magnetic insulation phase, neglecting the electron losses between the switch and the generating diode, exceeded 100 Ω. The duration of the rapid opening phase was less than 5 ns under optimum conditions. This method of plasma production does not require external plasma sources, and permits a wide variation of plasma density, which in turn allows high inductor currents and stored energies

  14. 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

  15. Re-do operations after failed multisegmental reconstructive arterial surgery for critical limb ischaemia.

    Science.gov (United States)

    Zukauskas, G; Ulevicius, H; Janusauskas, E

    1997-08-01

    The purpose of this study was to investigate the long-term graft patency rates after multisegmental arterial reconstruction for treatment of chronic critical limb ischemia, and to evaluate the role of re-do surgery in treatment of graft failure. A total of 449 aortofemoropopliteal/tibial grafts carried out over a 10-year period were retrospectively reviewed. All patients were operated upon with chronic critical limb ischemia grade III and IV according to the Fontaine classification; 221 operations were performed in one stage (group A), and 228 in two stages (group B). Distribution of graft failures in the postoperative period, re-do operations and their impact on limb salvage were investigated using life-table methods. During follow up, 62 cases of inflow graft thrombosis were observed (23 in group A and 39 in group B). To correct the inflow graft failure, 59 re-do procedures were performed (27 in group A, 32 in group B). Inflow graft failures were most common during 24 months after primary surgery. During the same period, 92 cases of isolated outflow graft thrombosis were observed (45 in group A and 47 in group B). Outflow graft thromboses were most common after 24-36 months. For treatment of recurrent symptoms caused by outflow graft thrombosis, 68 re-do operations were performed. The 5 year cumulative primary graft patency, secondary graft patency and limb salvage rates were 43.2%, 71.8% and 79.9% in group A, and 23.8%, 54% and 67.5% in group B respectively. In conclusion the long term primary graft patency rate after multisegmental aortofemoropopliteal/tibial reconstructive surgery is low and significantly lower, when compared with single segment reconstructions. Re-do operations have a positive impact on secondary long-term graft patency and limb salvage. PMID:9350799

  16. 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.

  17. Self-rectifying resistive-switching characteristics with ultralow operating currents in SiOxNy/AlN bilayer devices

    Science.gov (United States)

    Kwon, Jeong Yong; Park, Ju Hyun; Kim, Tae Geun

    2015-06-01

    We propose a SiOxNy/AlN bilayer resistive switching random access memory scheme to eliminate crosstalk in a crossbar array structure. We demonstrated forming-free self-rectifying behaviors at an ultralow operating current (below 200 nA) by optimizing the current compliance and operating voltage. The set and reset voltages were reduced using a thin AlN layer, and the voltages' on/off ratio and rectifying ratio were as high as 80 and 102, respectively. In addition, the device showed an endurance of 103 dc cycles and a retention time over 105 s.

  18. 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.

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

    Science.gov (United States)

    Garg, Rajnish; Murthy, Keshava; Rao, Shekhar; John, Colin

    2011-01-01

    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. PMID:21196674

  20. Functional connectivity separates switching operations in the posterior lateral frontal cortex

    NARCIS (Netherlands)

    Stelzel, C.; Basten, U.; Fiebach, C.J.

    2011-01-01

    Task representations consist of different aspects such as the representations of the relevant stimuli, the abstract rules to be applied, and the actions to be performed. To be flexible in our daily lives, we frequently need to switch between some or all aspects of a task. In the present study, we ex

  1. Pseudospark switches

    International Nuclear Information System (INIS)

    The pseudospark discharge is bound to a geometrical structure which is particularly well suited for switching high currents and voltages at high power levels. This type of discharge offers the potential for improvement in essentially all areas of switching operation: peak current and current density, current rise, stand-off voltage, reverse current capability, cathode life, and forward drop. The first pseudospark switch was built at CERN at 1981. Since then, the basic switching characteristics of pseudospark chambers have been studied in detail. The main feature of a pseudospark switch is the confinement of the discharge plasma to the device axis. The current transition to the hollow electrodes is spread over a rather large surface area. Another essential feature is the easy and precise triggering of the pseudospark switch from the interior of the hollow electrodes, relatively far from the main discharge gap. Nanosecond delay and jitter values can be achieved with trigger energies of less than 0.1 mJ, although cathode heating is not required. Pseudospark gaps may cover a wide range of high-voltage, high-current, and high-pulse-power switching at repetition rates of many kilohertz. This report reviews the basic researh on pseudospark switches which has been going on at CERN. So far, applications have been developed in the range of thyratron-like medium-power switches at typically 20 to 40 kV and 0.5 to 10 kA. High-current pseudospark switches have been built for a high-power 20 kJ pulse generator which is being used for long-term tests of plasma lenses developed for the future CERN Antiproton Collector (ACOL). The high-current switches have operated for several hundred thousand shots, with 20 to 50 ns jitter at 16 kV charging voltage and more than 100 kA peak current amplitude. (orig.)

  2. 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

  3. Preoperative statin is associated with decreased operative mortality in high risk coronary artery bypass patients

    Directory of Open Access Journals (Sweden)

    Maher Thomas D

    2010-02-01

    Full Text Available Abstract Background Statins are widely prescribed to patients with atherosclerosis. A retrospective database analysis was used to examine the role of preoperative statin use in hospital mortality, for patients undergoing isolated coronary artery bypass grafting (CABG. Methods The study population comprised 2377 patients who had isolated CABG at Allegheny General Hospital between 2000 and 2004. Mean age of the patients was 65 ± 11 years (range 27 to 92 years. 1594 (67% were male, 5% had previous open heart procedures, and 4% had emergency surgery. 1004 patients (42% were being treated with a statin at the time of admission. Univariate, bivariate (Chi2, Fisher's Exact and Student's t-tests and multivariate (stepwise linear regression analyses were used to evaluate the association of statin use with mortality following CABG. Results Annual prevalence of preoperative statin use was similar over the study period and averaged 40%. Preoperative clinical risk assessment demonstrated a 2% risk of mortality in both the statin and non-statin groups. Operative mortality was 2.4% for all patients, 1.7% for statin users and 2.8% for non-statin users (p Conclusions Between 2000 and 2004 less than 50% of patients at this institution were receiving statins before admission for isolated CABG. A retrospective analysis of this cohort provides evidence that preoperative statin use is associated with lower operative mortality in high-risk patients.

  4. Efficient, polarised, gain-switched operation of a Tm-doped fibre laser.

    Science.gov (United States)

    Simakov, Nikita; Hemming, Alex; Bennetts, Shayne; Haub, John

    2011-08-01

    We present a monolithic, robustly polarised thulium fibre laser which produces pulses with 25 ns duration and energy of up to 35 µJ. A pulsed 1.55 μm source was used to gain switch the laser at repetition rates of up to 300 kHz, producing average powers of up to 8 W at 2.044 µm. To the best of our knowledge this is the highest power gain-switched thulium fibre laser and it is also the first with a linearly polarised output. The large repetition rate, pulse energy and average power will enable efficient energy extraction from a large mode-area, polarisation maintaining thulium fibre amplifier. PMID:21934856

  5. Q-switched operation with Fox-Smith-Michelson laser cavity

    International Nuclear Information System (INIS)

    A new kind of three-mirror composite cavity, Fox-Smith-Michelson cavity has been configured. This laser cavity is capable of high power output, owing to the low threshold of Michelson cavity. Also, thanks to the mode selection function of Fox-Smith cavity, stable pulses at high repetition rate can be generated. In our experiment, 15.54 W CW output at 1064 nm has been achieved, with an optic-to-optic conversion efficiency of 42.2%. At the Q-switching repetition rate of 100 kHz, the average output power is 11.92 W, with an optic-to-optic conversion efficiency of 38.2%. For Q-switching frequency from 30 kHz to 100 kHz, the pulse width variation is below 4.4% and the amplitude variation is below 4.8%

  6. 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.

  7. Switching the Loaded Agent from Epirubicin to Cisplatin: Salvage Transcatheter Arterial Chemoembolization with Drug-eluting Microspheres for Unresectable Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Purpose: There is no consensus on switching anticancer agents loaded onto drug carriers in transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). This study aimed to evaluate the safety and clinical outcomes of TACE with cisplatin-loaded microspheres (CLM-TACE) in HCC patients refractory to TACE with epirubicin-loaded microspheres (ELM-TACE). Methods: Between February 2008 and June 2010, 85 patients with unresectable HCC refractory to ELM-TACE were enrolled to undergo CLM-TACE. The number of ELM-TACE sessions until judgment of resistance ranged from 1 to 4 (median, 2.1). CLM-TACE was performed using 50–100-μm superabsorbent polymer microspheres loaded with 1 mg cisplatin/1 mg microspheres together with hepatic arterial infusion of 25 mg cisplatin and 500 mg 5-fluorouracil per patient. Tumor responses were evaluated by computed tomography according to the European Association for the Study of the Liver criteria. Results: The median number of CLM-TACE treatment sessions was 1.8 (range, 1–5), and the mean total dose of cisplatin per session was 42.8 mg (range, 30.0–59.0). After 6 months, 3 (3.5%) patients achieved complete response, 31 (36.5%) had partial response, 15 (17.6%) had stable disease, and 36 (42.4%) had progressive disease. The median overall survival and time to treatment failure after initial CLM-TACE were 13.3 and 7.2 months, respectively. Overall, 9.4% of patients experienced grade 3/4 adverse events. Conclusions: witching the loaded agent from epirubicin to cisplatin is a safe, well-tolerated, and efficacious treatment strategy for salvage TACE with drug-eluting microspheres in HCC patients refractory to ELM-TACE.

  8. A novel low-jitter plasma-jet triggered gas switch operated at a low working coefficient.

    Science.gov (United States)

    Tie, Weihao; Liu, Shanhong; Liu, Xuandong; Zhang, Qiaogen; Pang, Lei; Liu, Longchen

    2014-02-01

    In this paper, we described the fabrication and testing of a novel plasma-jet triggered gas switch (PJTGS) operated at extremely low working coefficients with excellent triggered jitters. While the structure of the PJTGS is similar to that of a traditional three-electrode field-distortion gas switch, to improve its triggered performance we used a conical micro-plasma-gun with a needle-to-plate spark gap embedded in the trigger electrode. Applying a nanosecond pulse to the trigger electrode caused a spark discharge in the micro-plasma-gun. The electric field drove the discharge plasma to spray into the spark gap of the gas switch, causing fast breakdown. We tested the PJTGS with charging voltages of ±25 kV and a trigger voltage of +80 kV (5 ns rise time and 80 ns full width at half maximum) in two working modes. The PJTGS operated in Mode II had a lower triggered jitter and could be operated over a wider range of working coefficients than in Mode I under the same conditions. At working coefficients higher than 70%, we obtained sub-ns triggered jitters (<0.89 ns) from the PJTGS, at working coefficients lower than 50%, we obtained triggered jitters of 1.6-3.5 ns without no-fires or pre-fires. Even at a working coefficient of 27.4%, the PJTGS could still be triggered reliably with a delay time of 96.1 ns and a triggered jitter of 3.5 ns, respectively. PMID:24593358

  9. [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.

  10. Successful term pregnancy after Mustard operation for transposition of the great arteries.

    Science.gov (United States)

    Rousseil, M P; Irion, O; Béguin, F; Jaques, O; Adamec, R; Lerch, R; Friedli, B; Rifat, K

    1995-03-01

    Transposition of the great arteries is a complex cardiac malformation with poor prognosis without surgical correction. Since the introduction of surgical procedures such as the intra-auricular reorientation of the venous return (Mustard procedure), an increasing number of patients may reach adulthood and experience pregnancy. Because long-term complications after the Mustard operation include systemic heart failure, arrhythmias, venous return stenosis and pulmonary edema, hemodynamic changes during pregnancy and delivery may potentially engender life-threatening complications in these patients. We report the case of a 24-year-old primigravida who underwent a Mustard procedure at the age of 2 years for transposition of the great vessels, and who carried out a full-term pregnancy. The pregnancy was uneventful until the 34th week, when the woman developed signs of moderate right ventricular failure and frequent episodes of accelerated junctional rhythm. Digitalisation improved symptoms and elicited return to normal sinus rhythm. The patient delivered at term by elective cesarean section, under close hemodynamic monitoring. PMID:7781853

  11. 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.

  12. Reduction of operational amplifiers finite gain effects in switched-capacitor biquads

    Directory of Open Access Journals (Sweden)

    Radev Nikolay

    2005-01-01

    Full Text Available A combined approach for reducing the errors in the pole frequency f p, the pole Q - factor Qp and the magnitude at the pole frequency Hp, of switched capacitor biquads is presented. First, the conventional integrators in the biquads are replaced with gain-and offset-compensated integrators. Next, the errors Δ ƒp / ƒp, Δ Qp / Qp and Δ Hp / Hp are minimized by modifying three capacitances: two feedback capacitances and feed forward capacitance. The effectiveness of this approach is demonstrated by designing a band pass biquad.

  13. Resistance is Futile: STScI's Science Planning and Scheduling Team Switches From VMS to Unix Operations

    Science.gov (United States)

    Adler, D. S.

    2000-12-01

    The Science Planning and Scheduling Team (SPST) of the Space Telescope Science Institute (STScI) has historically operated exclusively under VMS. Due to diminished support for VMS-based platforms at STScI, SPST is in the process of transitioning to Unix operations. In the summer of 1999, SPST selected Python as the primary scripting language for the operational tools and began translation of the VMS DCL code. As of October 2000, SPST has installed a utility library of 16 modules consisting of 8000 lines of code and 80 Python tools consisting of 13000 lines of code. All tasks related to calendar generation have been switched to Unix operations. Current work focuses on translating the tools used to generate the Science Mission Specifications (SMS). The software required to generate the Mission Schedule and Command Loads (PASS), maintained by another team at STScI, will take longer to translate than the rest of the SPST operational code. SPST is planning on creating tools to access PASS from Unix in the short term. We are on schedule to complete the work needed to fully transition SPST to Unix operations (while remotely accessing PASS on VMS) by the fall of 2001.

  14. 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.

  15. 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.

  16. 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 $\

  17. Operation of Bidirectional Switches (DIAC) and Silicon Controlled Rectifiers (SCR) in Gamma-Radiation Environment

    International Nuclear Information System (INIS)

    Gamma-irradiation effects on the electrical parameters of the Diode AC switch (DIAC; PHI37 500) and Silicon Controlled Rectifier (SCR; 2N4444) devices have been studied in detail, where gamma-dose up to 137 x 106 rad was found to cause a serious permanent damage on their electrical characteristics. A pronounced increase in the break-over voltage (from 31.5 to 35 V), holding-current (from 13 to 53 mA) and holding voltage (from 22 to 32 V) of the DIAC is noticed. Besides, a severe decrease in the dynamic break-over voltage range (from 10 to 2.5 V) and negative resistance (from -750 to -168 ohm) is also observed. Exposing the SCRs to gamma-radiation causes their turn-on voltage and forward voltage drop values to increase from 0.8 to 2.8 V and from 1.4 to 4.5 V, respectively. Additionally, the holding current increases to 18 mA although its initial value is 3.5 mA. For the two devices, the linear dependence and high sensitivity of their electrical parameters to gamma-dose suggest the application of such devices in the field of radiation dosimetry

  18. 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

  19. Reducing operation voltages by introducing a low-k switching layer in indium–tin-oxide-based resistance random access memory

    Science.gov (United States)

    Jin, Fu-Yuan; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Pan, Chih-Hung; Lin, Chih-Yang; Chen, Po-Hsun; Chen, Min-Chen; Huang, Hui-Chun; Lo, Ikai; Zheng, Jin-Cheng; Sze, Simon M.

    2016-06-01

    In this letter, we inserted a low dielectric constant (low-k) or high dielectric constant (high-k) material as a switching layer in indium–tin-oxide-based resistive random-access memory. After measuring the two samples, we found that the low-k material device has very low operating voltages (‑80 and 110 mV for SET and RESET operations, respectively). Current fitting results were then used with the COMSOL software package to simulate electric field distribution in the layers. After combining the electrical measurement results with simulations, a conduction model was proposed to explain resistance switching behaviors in the two structures.

  20. 6.5-ns actively Q-switched Nd:YVO4 laser operating at 1.34 μm

    Institute of Scientific and Technical Information of China (English)

    Yongguang Zhao; Zhengping Wang; Haohai Yu; Lei Guo; Lijuan Chen; Shidong Zhuang; Xun Sun; Dawei Hu; Xinguang Xu

    2011-01-01

    @@ With a piano-concave cavity,diode-pumped continuous-wave(CW) and actively Q-switched Nd:YV04laser operating at 1.34 μm is demonstrated.Maximum CW output power of 4.76 W and Q-switched average output power of 2.64 W are obtained with output coupler(transmission T=3.9%).%With a planoconcave cavity, diode-pumped continuous-wave (CW) and actively (J-switched Nd:YVO4 laser operating at 1.34μm is demonstrated. Maximum CW output power of 4.76 W and Q-switehed average output power of 2.64 W are obtained with output coupler (transmission T = 3.9%). For the Q-switching operation, the theoretically calculated pulse energy and pulse width, with a pulse repetition frequency (PRF) range of 5-40 kHz, coincide with the experimental results. With a T = 11.9% output coupler, the maximum peak power of 24,3 kW and minimum pulse width of 6.5 ns are obtained when the PRF is 10 kHz. To the best of our knowledge, this is the shortest actively Q-switched pulse duration ever obtained in a 1.3-μm Nd-doped vanadate laser.

  1. 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.

  2. 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

    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...... 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...... 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...

  3. Synthetic molecular machines and polymer/monomer size switches that operate through dynamic and non-dynamic covalent changes.

    Science.gov (United States)

    Stadler, Adrian-Mihail; Ramírez, Juan

    2012-01-01

    The present chapter is focused on how synthetic molecular machines (e.g. shuttles, switches and molecular motors) and size switches (conversions between polymers and their units, i.e., conversions between relatively large and small molecules) can function through covalent changes. Amongst the interesting examples of devices herein presented are molecular motors and size switches based on dynamic covalent chemistry which is an area of constitutional dynamic chemistry. PMID:22169959

  4. Switching mode power supplies

    OpenAIRE

    Beard, David W.

    1980-01-01

    The subject of switching mode power supplies was examined. A comparison between linear regulators and switching mode power supplies was made to show the options available for the various types of convertors. Two switching mode power supplies were constructed and tested. The operating efficiency of both systems was found to be more than eighty percent over the specified input voltage and load current conditions. The switching mode power supply circuits required additional ...

  5. Heat Switches for ADRs

    Science.gov (United States)

    DiPirro, M. J.; Shirron, P. J.

    2014-01-01

    Heat switches are key elements in the cyclic operation of Adiabatic Demagnetization Refrigerators (ADRs). Several of the types of heat switches that have been used for ADRs are described in this paper. Key elements in selection and design of these switches include not only ON/OFF switching ratio, but also method of actuation, size, weight, and structural soundness. Some of the trade-off are detailed in this paper.

  6. 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.)

  7. Role magnesium in preventing post-operative atrial fibrillation after coronary artery bypass surgery

    International Nuclear Information System (INIS)

    To assess the role of 3 days of magnesium infusion after coronary artery bypass graft (CABG) surgery in preventing postoperative atrial fibrillation (AF). Prospective, randomized, non-blinded. All patients undergoing isolated, initial CABG surgery, and having sinus rhythm before surgery were alternatively randomized into the study or the control group. The exclusion criteria included: history of AF, implanted pacemaker, myocardial infarction postoperatively, use of left ventricular assist devices and renal failure. The patients in the study group received 10 mmol of magnesium sulphate (2.47 gm) dissolved in 100 ml of saline solution infused intravenously over 4 hours, for 3 days. The end point was development of AF for at least 15 minutes or more, or if an episode of AF had to be treated because of symptoms. A total of 220 patients were included in the study, 110 in each group. The incidence of AF was 9% in patients who received the three days of magnesium infusion. The patients without magnesium had an AF incidence of 23% (p<0.001). The hospital stay was also less in the treated group (p=0.055). A 3-days postoperative infusion of magnesium is safe and effective in reduction of possibly life-threatening AF, in patients undergoing primary coronary artery Bypass surgery. (author)

  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

    Sustainable H2O2 supply and cost-effective elimination of residual H2O2 are two key challenges associated with the successful application of Fenton reaction for contaminant removal. In this study, an innovative Bioelectro-Fenton system capable of alternate switching between microbial electrolysis...... 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...... a proof-in-concept new system for efficient and cost-effective H2O2 control and recalcitrant pollutants removal....

  9. 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.

  10. 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).

  11. 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...

  12. Viability of fuel switching of a gas-fired power plant operating in chemical looping combustion mode

    International Nuclear Information System (INIS)

    CLC (chemical looping combustion) promises to be a more efficient way of CO2 capture than conventional oxy-fuel combustion or post-combustion absorption. While much work has been done on CLC in the past two decades, the issue of multi-fuel compatibility has not been addressed sufficiently, especially with regard to plant layout and reactor design. In the present work, it is shown that this is non-trivial in the case of a CLC-based power plant. The underlying factors have been examined in depth and design criteria for fuel compatibility have been formulated. Based on these, a layout has been developed for a power plant which can run with either natural gas or syngas without requiring equipment changes either on the steam side or on the furnace side. The layout accounts for the higher CO2 compression costs associated with the use of syngas in place of natural gas. The ideal thermodynamic cycle efficiency, after accounting for the energy penalty of CO2 compression, is 43.11% and 41.08%, when a supercritical steam cycle is used with natural gas and syngas, respectively. It is shown that fuel switching can be enabled by incorporating the compatibility conditions at the design stage itself. - Highlights: • Concept of fuel sensitivity of plant layout with carbon capture and sequestration. • Power plant layout for natural gas and syngas as fuels. • Criteria for compatibility of air and fuel reactors for dual fuel mode operation. • Layout of a plant for carbon-neutral or carbon negative power generation

  13. 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.)

  14. High-energy passively Q-switched laser operation of Yb:Ca3La2(BO3)4 disordered crystal.

    Science.gov (United States)

    Wang, Lisha; Han, Wenjuan; Pan, Zhongben; Xu, Honghao; Chen, Xiaowen; Liu, Junhai; Yu, Haohai; Zhang, Huaijin

    2016-05-01

    Efficient high-energy passively Q-switched laser operation was demonstrated with Yb:Ca3La2(BO3)4 disordered crystal, producing an average output power of 3.0 W at 1018.7 nm, at a pulse repetition frequency of 5.0 kHz; the resulting pulse energy, duration, and peak power were 600 μJ, 5.3 ns, and 113.2 kW, respectively. PMID:27140354

  15. Körperliche Belastbarkeit und myokardiale Perfusion bei Patienten mit Transposition der großen Arterien nach Arterieller Switch Operation

    OpenAIRE

    Beckmann, Mareike

    2006-01-01

    Bei 22 Kindern mit einer Transposition der großen Arterien (TGA) wurde 10 Jahre nach Arterieller Switch Operation (ASO) der myokardiale Blutfluß (MBF) in Ruhe und unter Belastung mittels Positronenemissionstomographie (PET) gemessen sowie die Laborparameter Creatinkinase (CK), kardiales Troponin I (cTn I) und Glycogenphosphorylase Isoenzym BB (GPBB) bestimmt. Zusätzlich wurde eine qualitative Analyse der Myokardperfusion durchgeführt. Die Untersuchung zeigte im Vergleich zur gesunden Kontroll...

  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 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.

  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. High-power CW and passively Q-switched laser operation of Yb:GdCa4O(BO3)3 crystal

    Science.gov (United States)

    Chen, Xiaowen; Wang, Lisha; Liu, Junhai; Guo, Yunfeng; Han, Wenjuan; Xu, Honghao; Yu, Haohai; Zhang, Huaijin

    2016-05-01

    We demonstrate efficient high-power CW and passively Q-switched operations of Yb:GdCa4O(BO3)3 lasers. An output power of 18.2 W is generated at 1031.5 nm in CW mode, with optical-to-optical and slope efficiencies being respectively 55% and 70%, with respect to incident pump power. In passively Q-switched operation with a Cr4+:YAG crystal as saturable absorber, a maximum average output power of 15.6 W is produced at a pulse repetition rate of 91 kHz, with an optical-to-optical efficiency of 44%. Low-repetition-rate Q-switched action is also realized, generating an average output power of 4.2 W at 5.7 kHz, the resulting pulse energy and duration are 737 μJ and 3.6 ns, leading to a peak power amounting to 205 kW.

  1. Vertebral artery aneurysms.

    Directory of Open Access Journals (Sweden)

    Ravi Kumar C

    2000-04-01

    Full Text Available Vertebral artery (VA aneurysms are rare. We present our experience with three cases of VA aneurysms. Two aneurysms were located close to the origin of basilar artery while the third patient had a giant posterior inferior cerebellar artery aneurysm. These aneurysms were operated by the far lateral inferior suboccipital approach with good results.

  2. Percutaneous Retrograde Recanalization of a Chronic Total Coronary Artery Occlusion in a 7 Year Old

    Energy Technology Data Exchange (ETDEWEB)

    Natal-Hernandez, Luz; Meadows, Jeffery; Shunk, Kendrick A.; Boyle, Andrew J., E-mail: aboyle@medicine.ucsf.edu

    2013-03-15

    The arterial switch operation for correction of transposition of the great arteries can be complicated by late stenosis or occlusion of the coronary arteries that are re-implanted to the new aorta. We report the case of a young boy who underwent this operation as a neonate and was found to have an occluded anomalous left anterior descending artery (LAD) before age 3. Subsequent bypass surgery was complicated by anastomotic stricture and kinking of the left internal mammary artery graft to the LAD. At age 7, the LAD territory showed reversible ischemia on nuclear perfusion testing and he was referred for percutaneous coronary intervention. A combined approach with pediatric and adult interventional cardiologists resulted in successful retrograde PCI to recanalize the chronic total occlusion of the LAD. Important features of this technique in pediatric patients are discussed.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

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

    International Nuclear Information System (INIS)

    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. The effects of 10 cmH 2 O positive end-expiratory pressure on arterial oxygenation, respiratory mechanics and hemodynamic parameters in laparoscopic cholecystectomy operations

    Directory of Open Access Journals (Sweden)

    Fatma Çiçek

    2014-09-01

    Full Text Available Objective: The effects of 10cmH2O Positive End-expiratory Pressure (PEEP on respiratory mechanics, arterial oxygenation and hemodynamics in laparoscopic cholecystectomy operation were investigated. Methods: The study was planned on ASA I-II, 18-65 years old, forty patients scheduled for laparoscopic cholecystectomy under general anesthesia. The patients were divided into two groups which PEEP implemented Group 0 and 10 cmH2O PEEP applied Group P (Group 0, n=20; Group P, n=20. Heart rate, Mean arterial blood pressure, arterial oxygen saturation (SpO2, partial pressure of end-tidal carbon dioxide (PEtCO2, Peak inspiratory pressure (PİP, plato pressure (Pplato, partial pressure of oxygen in arterial blood (PaO2, partial pressure of carbon dioxide in arterial blood (PaCO2 values were evaluated at 5 minutes after induction, 5 minutes after CO2 insufflation, after the head-up position and the right side in the 10th and 30th minutes, After 10 minutes desufflation and in the recovery room. The Alveolar–arterial oxygen pressure gradient (P(A-a O2, the ratio of physiologic dead space over tidal volume (VD/VT, Arterial to End Tidal CO2 gradient (P(a-et CO2, static compliance (CS, dynamic compliance (CD were assessed same times. Results: The assessment between the groups, there were not statistical differences about mean blood pressure, heart rate, SpO2, PetCO2, PaO2, plateau pressure, and P (A-a values (p>0.05. Peak inspiratory pressure was higher in Group P (p<0.05. Peak inspiratory pressure and plateau pressure increased with CO2 insufflation in both groups. PaCO2 and P(a-et CO2 were higher statistically significantly in Group 0 (p<0.05. There was no difference between the groups in terms of the PetCO2 values. VD/VT ratios were statistically significantly lower in the Group P (p<0.05. There was no difference at static compliance values between the groups, dynamic compliance was lower in Group P. According to the initial values, there was a decrease in

  12. 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.

  13. Evaluations of topical application of tranexamic acid on post-operative blood loss in off-pump coronary artery bypass surgery

    OpenAIRE

    Habibollah Hosseini; Ali Akbar Rahimianfar; Mohammad Hassan Abdollahi; Mohammad Hossein Moshtaghiyoon; Mahdi Haddadzadeh; Asefeh Fekri; Kazem Barzegar; Fatemeh Rahimianfar

    2014-01-01

    Objective: One of the major complications of cardiac surgery is the presence of post-operative bleeding. The aim of the present study was to investigate the topical application of tranexamic acid in the pericardial cavity on post-operative bleeding in off-pump coronary artery bypass graft (CABG) surgery. Materials and Methods: This study was on 71 patients who underwent off-pump CABG. The anesthesia and surgery methods were the same for all patients. Patients were assigned to two equal groups...

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. High-speed switching characteristics of integrated optoelectronic crossbar switch

    Science.gov (United States)

    Gouin, Francois L.; Almeida, Carlos; Callender, Claire L.; Robitaille, Lucie; Noad, Julian P.

    1999-04-01

    Optoelectronic (OE) switching is a promising approach for routing signals in fiber optic networks. Recently, the integration of a 4 X 4 MSM array with optical surface waveguides has been reported. This technique greatly simplifies the packaging of an OE switch. The on-chip polyimide optical waveguides perform the optical signal distribution to a matrix of MSMs which are responsible for the switching operation itself. Photoresponse bandwidths exceeding 4 GHz have been demonstrated. Another important characteristic of a switch is the switching speed since it determines the reconfiguration time. Mechanical and thermal optical waveguide switches offer switching speeds of the order of milliseconds which is sufficient for network traffic management but too slow for packet switching. We report measurements on the switching characteristics of a 4 X 4 optoelectronic switch performed in both the frequency and time domain. In the time domain, the individual crosspoints exhibit a rise time of 3 ns. However, a sizeable overshoot and ringing settles only after 35 ns. This constitutes the reconfiguration time at present. This is confirmed by measurements in the frequency domain of the electrical transmission from control line to output line. The 3-dB switching bandwidth is a few hundred megahertz. The 35 ns reconfiguration time indicates that it is already suitable for packet switching in a 10 Mb/s network. Switching speed measurements on individual MSMs suggests that modifications to the switch circuit could improve the switching time. The switch could also find application as a component in the wavelength conversion circuit of a WDM fiber optic network.

  19. Towards single molecule switches.

    Science.gov (United States)

    Zhang, Jia Lin; Zhong, Jian Qiang; Lin, Jia Dan; Hu, Wen Ping; Wu, Kai; Xu, Guo Qin; Wee, Andrew T S; Chen, Wei

    2015-05-21

    The concept of using single molecules as key building blocks for logic gates, diodes and transistors to perform basic functions of digital electronic devices at the molecular scale has been explored over the past decades. However, in addition to mimicking the basic functions of current silicon devices, molecules often possess unique properties that have no parallel in conventional materials and promise new hybrid devices with novel functions that cannot be achieved with equivalent solid-state devices. The most appealing example is the molecular switch. Over the past decade, molecular switches on surfaces have been intensely investigated. A variety of external stimuli such as light, electric field, temperature, tunneling electrons and even chemical stimulus have been used to activate these molecular switches between bistable or even multiple states by manipulating molecular conformations, dipole orientations, spin states, charge states and even chemical bond formation. The switching event can occur either on surfaces or in break junctions. The aim of this review is to highlight recent advances in molecular switches triggered by various external stimuli, as investigated by low-temperature scanning tunneling microscopy (LT-STM) and the break junction technique. We begin by presenting the molecular switches triggered by various external stimuli that do not provide single molecule selectivity, referred to as non-selective switching. Special focus is then given to selective single molecule switching realized using the LT-STM tip on surfaces. Single molecule switches operated by different mechanisms are reviewed and discussed. Finally, molecular switches embedded in self-assembled monolayers (SAMs) and single molecule junctions are addressed. PMID:25757483

  20. 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).

  1. Biochemical switching device: how to turn on (off) the switch.

    Science.gov (United States)

    Okamoto, M; Sakai, T; Hayashi, K

    1989-01-01

    We previously showed with computer simulations that cyclic enzyme systems have the reliability of ON-OFF types of operation (McCulloch-Pitts' neuronic equation) and the applicability for a switching circuit in a biocomputer. The switching time was inevitably determined in accordance with the difference in amount between two inputs of the system. This characteristic is, however, a disadvantage for practical use of a switching device; we need to improve the system in order for the switching time to optionally be changed. We shall present here how to turn on (off) the switch independently of the modes of two inputs. By introducing pulse perturbation, we could optionally set up the switching time of a cyclic enzyme system (biochemical switching device). PMID:2720139

  2. CIRCUIT SWITCHING VERSUS PACKET SWITCHING

    OpenAIRE

    Sneps-Sneppe, Manfred

    2015-01-01

    Communication specialists around the world are facing the same problem: shifting from circuit switching (CS) to packet switching (CS). Communication service providers are favoring “All-over-IP” technologies hoping to boost their profits by providing multimedia services. The main stakeholder in this field of the paradigm shift is the industry itself: packet switching hardware manufacturers are going to earn billions of dollars and thus pay engineers and journalists many millions for the promot...

  3. 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...

  4. Optical switches and switching methods

    Energy Technology Data Exchange (ETDEWEB)

    Doty, Michael

    2008-03-04

    A device and method for collecting subject responses, particularly during magnetic imaging experiments and testing using a method such as functional MRI. The device comprises a non-metallic input device which is coupled via fiber optic cables to a computer or other data collection device. One or more optical switches transmit the subject's responses. The input device keeps the subject's fingers comfortably aligned with the switches by partially immobilizing the forearm, wrist, and/or hand of the subject. Also a robust nonmetallic switch, particularly for use with the input device and methods for optical switching.

  5. Lessons learned: the switch from VMS to UNIX operations for the STScI's Science and Mission Scheduling Branch

    Science.gov (United States)

    Adler, David S.; Workman, William M., III; Chance, Don

    2004-09-01

    The Science and Mission Scheduling Branch (SMSB) of the Space Telescope Science Institute (STScI) historically operated exclusively under VMS. Due to diminished support for VMS-based platforms at STScI, SMSB recently transitioned to Unix operations. No additional resources were available to the group; the project was SMSB's to design, develop, and implement. Early decisions included the choice of Python as the primary scripting language; adoption of Object-Oriented Design in the development of base utilities; and the development of a Python utility to interact directly with the Sybase database. The project was completed in January 2004 with the implementation of a GUI to generate the Command Loads that are uplinked to HST. The current tool suite consists of 31 utilities and 271 tools comprising over 60,000 lines of code. In this paper, we summarize the decision-making process used to determine the primary scripting language, database interface, and code management library. We also describe the finished product and summarize lessons learned along the way to completing the project.

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

    OpenAIRE

    Jia Ge; Fok, Mable P.

    2015-01-01

    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...

  7. High Power Continuous-Wave and Acousto-Optic Q-Switched Nd:GdVO4 Laser Operated at 912 nm

    Institute of Scientific and Technical Information of China (English)

    GAO Jing; Yu Xin; CHEN Fei; LI Xu-Dong; ZHANG Zhen; YU Jun-Hua; WANG Yue-Zhu

    2008-01-01

    We present a high power and efficient operation of the 4F3/2→4I9/2transition in Nd:GdVO4 at 912 nm.In the cw mode,the maximum output power of 8.6 W is achieved when the incident pump power is 40.3W,leading to a slope efficiency of 33.3%and an optical-optical efficiency of 21.3%.To the best of our knowledge,this is the highest cw laser power at 912nm obtained with the conventional Nd:GdVO4 crystal.Pulsed operation of 912 nm laser has also been realized by inserting a small acousto-optic (A-O)Q-Switch inside the resonator.As a result,the minimal pulse width of 20ns and the average laser power 1.43 W at the repetition rate of 10kHz are obtained,corresponding to 7.1 kW peak power.We believe that this is the highest laser peak power at 912 nm.Furthermore.duration of 65 ns has also been acquired when the repetition rate is 100 kHz.

  8. MCT/MOSFET Switch

    Science.gov (United States)

    Rippel, Wally E.

    1990-01-01

    Metal-oxide/semiconductor-controlled thyristor (MCT) and metal-oxide/semiconductor field-effect transistor (MOSFET) connected in switching circuit to obtain better performance. Offers high utilization of silicon, low forward voltage drop during "on" period of operating cycle, fast turnon and turnoff, and large turnoff safe operating area. Includes ability to operate at high temperatures, high static blocking voltage, and ease of drive.

  9. 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).

  10. The Molecular Switch of Telomere Phages: High Binding Specificity of the PY54 Cro Lytic Repressor to a Single Operator Site.

    Science.gov (United States)

    Hammerl, Jens Andre; Roschanski, Nicole; Lurz, Rudi; Johne, Reimar; Lanka, Erich; Hertwig, Stefan

    2015-06-01

    Temperate bacteriophages possess a molecular switch, which regulates the lytic and lysogenic growth. The genomes of the temperate telomere phages N15, PY54 and ɸKO2 harbor a primary immunity region (immB) comprising genes for the prophage repressor, the lytic repressor and a putative antiterminator. The roles of these products are thought to be similar to those of the lambda proteins CI, Cro and Q, respectively. Moreover, the gene order and the location of several operator sites in the prototype telomere phage N15 and in ɸKO2 are also reminiscent of lambda-like phages. By contrast, in silico analyses revealed the presence of only one operator (O\\(_{\\rm{R}}\\)3) in PY54. The purified PY54 Cro protein was used for EMSA studies demonstrating that it exclusively binds to a 16-bp palindromic site (O\\(_{\\rm{R}}\\)3) upstream of the prophage repressor gene. The O\\(_{\\rm{R}}\\)3 operator sequences of PY54 and ɸKO2/N15 only differ by their peripheral base pairs, which are responsible for Cro specificity. PY54 cI and cro transcription is regulated by highly active promoters initiating the synthesis of a homogenious species of leaderless mRNA. The location of the PY54 Cro binding site and of the identified promoters suggests that the lytic repressor suppresses cI transcription but not its own synthesis. The results indicate an unexpected diversity of the growth regulation mechanisms in lambda-related phages. PMID:26043380

  11. The Molecular Switch of Telomere Phages: High Binding Specificity of the PY54 Cro Lytic Repressor to a Single Operator Site

    Directory of Open Access Journals (Sweden)

    Jens Andre Hammerl

    2015-06-01

    Full Text Available Temperate bacteriophages possess a molecular switch, which regulates the lytic and lysogenic growth. The genomes of the temperate telomere phages N15, PY54 and ɸKO2 harbor a primary immunity region (immB comprising genes for the prophage repressor, the lytic repressor and a putative antiterminator. The roles of these products are thought to be similar to those of the lambda proteins CI, Cro and Q, respectively. Moreover, the gene order and the location of several operator sites in the prototype telomere phage N15 and in ɸKO2 are also reminiscent of lambda-like phages. By contrast, in silico analyses revealed the presence of only one operator (O\\(_{\\rm{R}}\\3 in PY54. The purified PY54 Cro protein was used for EMSA studies demonstrating that it exclusively binds to a 16-bp palindromic site (O\\(_{\\rm{R}}\\3 upstream of the prophage repressor gene. The O\\(_{\\rm{R}}\\3 operator sequences of PY54 and ɸKO2/N15 only differ by their peripheral base pairs, which are responsible for Cro specificity. PY54 cI and cro transcription is regulated by highly active promoters initiating the synthesis of a homogenious species of leaderless mRNA. The location of the PY54 Cro binding site and of the identified promoters suggests that the lytic repressor suppresses cI transcription but not its own synthesis. The results indicate an unexpected diversity of the growth regulation mechanisms in lambda-related phages.

  12. 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...

  13. 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...

  14. 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.

  15. [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. PMID:1771568

  16. Increase in caveolae and caveolin-1 expression modulates agonist-induced contraction and store- and receptor-operated Ca(2+) entry in pulmonary arteries of pulmonary hypertensive rats.

    Science.gov (United States)

    Jiao, Hai-Xia; Mu, Yun-Ping; Gui, Long-Xin; Yan, Fu-Rong; Lin, Da-Cen; Sham, James S K; Lin, Mo-Jun

    2016-09-01

    Caveolin-1 (Cav-1) is a major component protein associated with caveolae in the plasma membrane and has been identified as a regulator of store-operated Ca(2+) entry (SOCE) and receptor-operated Ca(2+) entry (ROCE). However, the contributions of caveolae/Cav-1 of pulmonary arterial smooth muscle cells (PASMCs) to the altered Ca(2+) signaling pathways in pulmonary arteries (PAs) during pulmonary hypertension (PH) have not been fully characterized. The present study quantified caveolae number and Cav-1 expression, and determined the effects of caveolae disruption on ET-1, cyclopiazonic acid (CPA) and 1-Oleoyl-2-acetyl-glycerol (OAG)-induced contraction in PAs and Ca(2+) influx in PASMCs of chronic hypoxia (CH)- and monocrotaline (MCT)-induced PH rats. We found that the number of caveolae, and the Cav-1 mRNA and protein levels were increased significantly in PASMCs in both PH models. Disruption of caveolae by cholesterol depletion with methyl-β-cyclodextrin (MβCD) significantly inhibited the contractile response to ET-1, CPA and OAG in PAs of control rats. ET-1, SOCE and ROCE-mediated contractile responses were enhanced, and their susceptibility to MβCD suppression was potentiated in the two PH models. MβCD-induced inhibition was reversed by cholesterol repletion. Introduction of Cav-1 scaffolding domain peptide to mimic Cav-1 upregulation caused significant increase in CPA- and OAG-induced Ca(2+) entry in PASMCs of control, CH and MCT-treated groups. Our results suggest that the increase in caveolae and Cav-1 expression in PH contributes to the enhanced agonist-induced contraction of PA via modulation of SOCE and ROCE; and targeting caveolae/Cav-1 in PASMCs may provide a novel therapeutic strategy for the treatment of PH. PMID:27311393

  17. 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...

  18. 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...

  19. 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)

  20. Arterial Ageing

    OpenAIRE

    Lee, Seung-Jun; Park, Sung-Ha

    2013-01-01

    Arterial ageing is characterized by age associated degeneration and sclerosis of the media layer of the large arteries. However, besides ageing, clinical conditions, which enhance oxidative stress and inflammation act to accelerate the degree of arterial ageing. In this review, we summarized the pathophysiology and contributing factors that accelerate arterial ageing. Among them, we focused on hypertension, the renin-angiotensin-aldosterone system and vascular inflammation which are modifiabl...

  1. 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

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

    Science.gov (United States)

    Geenens, Rachel; Famaey, Nele; Gijbels, Andy; Verhelle, Silke; Vinckier, Stefan; Vander Sloten, Jos; Herijgers, Paul

    2016-01-01

    Background 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. Methods 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. Results 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. Conclusions Arterial clamping induces different acute and long-term injury to the vessel wall of atherosclerotic and healthy arteries. PMID:27295082

  3. 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.

  4. A New Soft Switching Current fed DC-DC Converter for Medium Power Applications

    OpenAIRE

    Majid Delshad

    2008-01-01

    In this paper a new zero voltage switching current fed half bridge converter with an auxiliary circuit is proposed. The auxiliary circuit not only absorbs the voltage surge across switches at turn off instance, but also provides zero voltage switching condition for all converter switches. Therefore in this converter the efficiency is higher than hard switching counterpart and also main switches voltage stresses decrease. Since the switches in auxiliary circuit operate under soft switching con...

  5. High-pulse-energy passively Q-switched quasi-monolithic microchip lasers operating in the sub-100-ps pulse regime.

    Science.gov (United States)

    Nodop, D; Limpert, J; Hohmuth, R; Richter, W; Guina, M; Tünnermann, A

    2007-08-01

    We present passively Q-switched microchip lasers with items bonded by spin-on-glass glue. Passive Q-switching is obtained by a semiconductor saturable absorber mirror. The laser medium is a Nd:YVO(4) crystal. These lasers generate pulse peak powers up to 20 kW at a pulse duration as short as 50 ps and pulse repetition rates of 166 kHz. At 1064 nm, a linear polarized transversal and longitudinal single-mode beam is emitted. To the best of our knowledge, these are the shortest pulses in the 1 microJ energy range ever obtained with passively Q-switched microchip lasers. The quasi-monolithic setup ensures stable and reliable performance. PMID:17671554

  6. 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.

  7. Splanchnic artery aneurysms

    Directory of Open Access Journals (Sweden)

    Davidović Lazar B.

    2006-01-01

    Full Text Available Introduction. Splanchnic artery aneurysms are uncommon but important vascular entity because nearly 25% of all cases present as surgical emergency. Objective. The purpose of our study was to present nine patients operated on at the Institute of cardiovascular diseases, as well as literature review of clinical presentation of the disease. Method. There were three splenic artery aneurysms, two celiac trunk aneurysms, and one aneurysm of the hepatic, superior mesenteric, inferior mesenteric and gastroduodenal artery. All patients were males, mean aged 67.5 years (60-73. In four patients, splanchnic artery aneurysm was discovered accidentally during routine ultrasonographic and angiographic examinations of the abdominal aorta. At that time, arteriovenous fistula was diagnosed in a patient No 1; it was formed after rupture of the splenic artery aneurysm into the splenic vein. Three aneurysms were manifested by abdominal pain and palpable pulsating abdominal mass. Two patients were admitted as urgent cases in the state of hemorrhagic shock and signs of intraabdominal bleeding due to rupture of the splenic and hepatic arteries. In 7 cases, diagnosis was made preoperatively by means of ultrasonography and angiography; in two patients, accurate diagnosis was confirmed during surgery. Results. Proximal and distal ligation of the artery was performed in a patient with rupture of the splenic aneurysm into the splenic vein that caused arteriovenous fistula. Gastroduodenal artery aneurysm was treated by trans-aneurysmatic ligation of its "entering" and "exiting" branches. Aneurysms of distal part of the superior mesenteric and splenic artery were resected without further reconstruction. Partial resection of the aneurysm and endoaneurysmorrhaphy was carried out in one case of celiac trunk aneurysm, and in another, after aneurysm resection, the restoration of blood flow through the hepatic and lienal artery was achieved by Dacron grafts. In a patient with the

  8. 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.

  9. Switch for serial or parallel communication networks

    Science.gov (United States)

    Crosette, D.B.

    1994-07-19

    A communication switch apparatus and a method for use in a geographically extensive serial, parallel or hybrid communication network linking a multi-processor or parallel processing system has a very low software processing overhead in order to accommodate random burst of high density data. Associated with each processor is a communication switch. A data source and a data destination, a sensor suite or robot for example, may also be associated with a switch. The configuration of the switches in the network are coordinated through a master processor node and depends on the operational phase of the multi-processor network: data acquisition, data processing, and data exchange. The master processor node passes information on the state to be assumed by each switch to the processor node associated with the switch. The processor node then operates a series of multi-state switches internal to each communication switch. The communication switch does not parse and interpret communication protocol and message routing information. During a data acquisition phase, the communication switch couples sensors producing data to the processor node associated with the switch, to a downlink destination on the communications network, or to both. It also may couple an uplink data source to its processor node. During the data exchange phase, the switch couples its processor node or an uplink data source to a downlink destination (which may include a processor node or a robot), or couples an uplink source to its processor node and its processor node to a downlink destination. 9 figs.

  10. SWITCHED-CAPACITOR BASED STEP-DOWN RESONANT CONVERTERS

    Institute of Scientific and Technical Information of China (English)

    Y.P.B.Yeung; K.W.E.Cheng; K.K.Law

    2001-01-01

    A family of switched-capacitor based resonant converters is present.All converters are in step-downmode.By adding different number of switched-capacitor cells,different output voltage conversion ratio can beobtained.All switching devices in the converters operate under zero-current switching.Both high frequencyoperations and high efficiency are possible.

  11. Ultimate-fast all-optical switching of a microcavity

    NARCIS (Netherlands)

    Yuce, E.

    2013-01-01

    In this thesis we study ultrafast all-optical switching of microcavities. We employ the electronic Kerr effect to switch the resonance frequency of microcavities operating at telecom wavelengths. We observe the fastest possible switching of a microcavity resonance within 300 fs. The switching speed

  12. Comparing Switch Costs: Alternating Runs and Explicit Cuing

    Science.gov (United States)

    Altmann, Erik M.

    2007-01-01

    The task-switching literature routinely conflates different operational definitions of switch cost, its predominant behavioral measure. This article is an attempt to draw attention to differences between the two most common definitions, alternating-runs switch cost (ARS) and explicit-cuing switch cost (ECS). ARS appears to include both the costs…

  13. 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

  14. 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.

  15. 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

  16. 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.

  17. High-energy passively Q-switched operation of Yb:GdCa(4)O(BO(3))(3) laser with a GaAs semiconductor saturable absorber.

    Science.gov (United States)

    Chen, Xiaowen; Wang, Lisha; Han, Wenjuan; Guo, Yunfeng; Xu, Honghao; Yu, Haohai; Zhang, Huaijin; Liu, Junhai

    2015-11-16

    High-energy passively Q-switched operation of a Yb:GdCa(4)O(BO(3))(3) laser is demonstrated, with a GaAs crystal plate acting as saturable absorber. An average output power of 1.31 W at 1027 nm is produced at a pulse repetition rate of 1.92 kHz, the resulting pulse energy, duration, and peak power being respectively 0.68 mJ, 9.0 ns, and 75.6 kW. The shortest pulse duration obtained is 4.9 ns; whereas the maximum pulse energy achievable amounts to 0.83 mJ, which proves to be nearly one order of magnitude higher than ever generated from Yb or Nd lasers passively Q-switched by a GaAs saturable absorber. PMID:26698515

  18. 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.

  19. 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.

  20. Research on a Novel Soft-Switching Buck Converter

    OpenAIRE

    Peng Ge; Ben Niu; Yuanbin Li

    2013-01-01

    Based on classical zero voltage transition buck pwm converter, an ideal buck converter with pwm-controlled soft-switching circuit is proposed. The proposed auxiliary circuit allows the main switch to operate with zero-voltage switching. Besides, all of the semiconductor devices operate under soft-switching conditions. Thus, losses were reduced. It was analyzed in detail to demonstrate the operating principle of the novel circuit. Finally, simulation results are given analysis and the simulati...

  1. 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.

  2. A study on low-power, nanosecond operation and multilevel bipolar resistance switching in Ti/ZrO2/Pt nonvolatile memory with 1T1R architecture

    International Nuclear Information System (INIS)

    Low-power, bipolar resistive switching (RS) characteristics in the Ti/ZrO2/Pt nonvolatile memory with one transistor and one resistor (1T1R) architecture were reported. Multilevel storage behavior was observed by modulating the amplitude of the MOSFET gate voltage, in which the transistor functions as a current limiter. Furthermore, multilevel storage was also executed by controlling the reset voltage, leading the resistive random access memory (RRAM) to the multiple metastable low resistance state (LRS). The experimental results on the measured electrical properties of the various sized devices confirm that the RS mechanism of the Ti/ZrO2/Pt structure obeys the conducting filaments model. In application, the devices exhibit high-speed switching performances (250 ns) with suitable high/low resistance state ratio (HRS/LRS > 10). The LRS of the devices with 10 year retention ability at 80 °C, based on the Arrhenius equation, is also demonstrated in the thermal accelerating test. Furthermore, the ramping gate voltage method with fixed drain voltage is used to switch the 1T1R memory cells for upgrading the memory performances. Our experimental results suggest that the ZrO2-based RRAM is a prospective alternative for nonvolatile multilevel memory device applications. (paper)

  3. Switched Matrix Accelerator

    International Nuclear Information System (INIS)

    We describe a new concept for a microwave circuit functioning as a charged-particle accelerator at mm-wavelengths, permitting an accelerating gradient higher than conventional passive circuits can withstand consistent with cyclic fatigue. The device provides acceleration for multiple bunches in parallel channels, and permits a short exposure time for the conducting surface of the accelerating cavities. Our analysis includes scalings based on a smooth transmission line model and a complementary treatment with a coupled-cavity simulation. We provide also an electromagnetic design for the accelerating structure, arriving at rough dimensions for a seven-cell accelerator matched to standard waveguide and suitable for bench tests at low power in air at 91.392. GHz. A critical element in the concept is a fast mm-wave switch suitable for operation at high-power, and we present the considerations for implementation in an H-plane tee. We discuss the use of diamond as the photoconductor switch medium

  4. 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.

  5. 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. PMID:25827177

  6. The Relationship between Earnings before Interest and Taxes and Operating Cash Flow and Stock Return under the Condition of Information Asymmetry in Abadan and Arak Petrochemical Companies through Markov-Switching Approach

    Directory of Open Access Journals (Sweden)

    Abolghasem Masihabadi

    2015-06-01

    Full Text Available This research investigated the relationship between earnings before interest and taxes and operating cash flow and shareholders’ return in Abadan and Arak Petrochemical Companies. This relationship was tested under the condition of information asymmetry. Nonlinear Markov-Switching approach was adopted to test the hypotheses. The results of empirical tests through the data in 2001-2010 indicated that in Arak Petrochemical Company, both variables of earnings before interest and taxes and operating cash flow had significant relationship with stock return of company. However, in Abadan Petrochemical Company, only the variable of earnings before interest and taxes had significant and positive relationship with stock return of company. Increase in information asymmetry showed that variable of operating cash flow had a stronger relationship with stock return of companies than the variable of earnings before interest and taxes. In other words, under the condition of information asymmetry, cash flow variables had higher correlation with stock return of companies than accrual variables.

  7. 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...

  8. 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.

  9. Switched steerable multiple beam antenna system

    Science.gov (United States)

    Iwasaki, Richard S.

    1988-09-01

    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.

  10. Pharmacokinetic Comparison of Scutellarin and Paeoniflorin in Sham-Operated and Middle Cerebral Artery Occlusion Ischemia and Reperfusion Injury Rats after Intravenous Administration of Xin-Shao Formula.

    Science.gov (United States)

    Li, Yueting; Lu, Yuan; Hu, Jianchun; Gong, Zipeng; Yang, Wu; Wang, Aimin; Zheng, Jiang; Liu, Ting; Chen, Tingting; Hu, Jie; Mi, Ling; Li, Yongjun; Lan, Yanyu; Wang, Yonglin

    2016-01-01

    Xin-Shao formula is a folk remedy widely used in China to prevent and cure stroke. Cerebral ischemic reperfusion (I/R) injury often takes place during the treatment of stroke. Information about the pharmacokinetic behavior of the remedy under cerebral I/R injury conditions is lacking. The present study aimed to compare the pharmacokinetic properties of scutellarin and paeoniflorin, two major bioactive components of Xin-Shao formula, under physiological state in cerebral I/R injury rats. Neurobehavioral dysfunction was evaluated and cerebral infarcted volume was measured in middle cerebral artery occlusion I/R injury (MCAO) rats. Plasma samples were collected at various time points after a single dose (intravenous, i.v.) of Xin-Shao formula. The levels of plasma scutellarin and paeoniflorin at the designed time points were determined by a UPLC-MS/MS method, and drug concentration versus time plots were constructed to estimate pharmacokinetic parameters. Increase in terminal elimination half-life (t1/2z) and mean residence time (MRT(0-t)) of scutellarin as well as elevation in area under the plasma drug concentration-time curve from 0 h to the terminal time point (AUC(0-t)) and maximum plasma drug concentration (Cmax) of paeoniflorin, along with decreased clearance of paeoniflorin and scutellarin as well as reduced apparent volume of distribution (Vz) of paeoniflorin, were observed in MCAO rats, compared with those in sham-operated animals. The elimination of scutellarin and paeoniflorin were reduced in cerebral I/R injury reduced rats. PMID:27617986

  11. The operation mode strategies of Finnish firms in South Korea with a special emphasis on mode switching, mode stretching and mode combination strategies

    OpenAIRE

    Huhtanen, Heikki

    2009-01-01

    ABSTRACT Foreign operation modes and their use are of crucial importance to any company that operates in an international environment. The previous research on foreign operation modes has tended to view these modes from a rather simple, static perspective, which, arguably, does not necessarily reflect the reality of foreign operation mode use in many international companies. To better capture the nuances of the foreign operation mode use in contemporary international business environm...

  12. Transposition of the great arteries.

    Science.gov (United States)

    Martins, Paula; Castela, Eduardo

    2008-01-01

    . 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. PMID:18851735

  13. 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.

  14. Switched reluctance drives for electric vehicle applications

    OpenAIRE

    Andrada Gascón, Pedro; Torrent Burgués, Marcel; Blanqué Molina, Balduino; Perat Benavides, Josep Ignasi

    2003-01-01

    Electric vehicles are the only alternative for a clean, efficient and environmentally friendly urban transport system. With the increasing interest in electric drives for electric vehicle propulsion. This paper first tries to explain why the switched reluctance drive is a strong candidate for electric vehicle applications. It then gives switched reluctance drive design guidelines for battery or fuel cell operated electric vehicles. Finally, it presents the design and simulation of a switched ...

  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 nine...

  16. SEPP-ZVS High Frequency Inverter Incorporating Auxiliary Switch

    Science.gov (United States)

    Ogiwara, Hiroyuki; Itoi, Misao; Nakaoka, Mutsuo

    This paper presents a novel circuit topology to attain ZVS operation of a high frequency inverter over a wide range output power regulation using a PWM control technique by connecting an auxiliary switch to the conventional single ended push-pull (SEPP) ZVS high frequency inverter. A switching current is injected into the main switches via the auxiliary switch only during the short period between its turn-on and off times to supply a current required for its ZVS operation.

  17. 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...

  18. A sub-1-volt nanoelectromechanical switching device

    Science.gov (United States)

    Lee, Jeong Oen; Song, Yong-Ha; Kim, Min-Wu; Kang, Min-Ho; Oh, Jae-Sub; Yang, Hyun-Ho; Yoon, Jun-Bo

    2013-01-01

    Nanoelectromechanical (NEM) switches have received widespread attention as promising candidates in the drive to surmount the physical limitations currently faced by complementary metal oxide semiconductor technology. The NEM switch has demonstrated superior characteristics including quasi-zero leakage behaviour, excellent density capability and operation in harsh environments. However, an unacceptably high operating voltage (4-20 V) has posed a major obstacle in the practical use of the NEM switch in low-power integrated circuits. To utilize the NEM switch widely as a core device component in ultralow power applications, the operation voltage needs to be reduced to 1 V or below. However, sub-1 V actuation has not yet been demonstrated because of fabrication difficulties and irreversible switching failure caused by surface adhesion. Here, we report the sub-1 V operation of a NEM switch through the introduction of a novel pipe clip device structure and an effective air gap fabrication technique. This achievement is primarily attributed to the incorporation of a 4-nm-thick air gap, which is the smallest reported so far for a NEM switch generated using a `top-down' approach. Our structure and process can potentially be utilized in various nanogap-related applications, including NEM switch-based ultralow-power integrated circuits, NEM resonators, nanogap electrodes for scientific research and sensors.

  19. 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...

  20. One-stage neonatal corrective repair for d-transposition of the great arteries and complete atrio-ventricular canal.

    Science.gov (United States)

    Bautista-Hernandez, Victor; Marx, Gerald R; del Nido, Pedro J

    2007-01-01

    Association of d-transposition of the great arteries and complete atrio-ventricular canal constitutes an uncommon and complex cardiac anomaly usually associated with poor prognosis. We report our experience on one-stage neonatal repair for d-transposition of the great arteries and complete atrio-ventricular canal. Between August 1997 and 2005, four patients (two males and two females) underwent anatomical correction for d-transposition of the great arteries and complete atrio-ventricular canal using an arterial switch procedure and two-patch repair. Mean age and weight at operation were 20 days (range from 3 to 28 days) and 3.2kg (range from 2.7 to 3.5kg), respectively. None of the patients received preoperative palliative procedure. Associated lesions were left outflow tract obstruction in three patients and multiple muscular ventricular septal defects in two patients. All four patients survived the operation. There was one in-hospitality death due to fungal sepsis. One patient required late re-operation for left ventricular outflow tract obstruction and left atrio-ventricular valve regurgitation. For a mean follow-up of 67 months (range from 51 to 90 months) all patients are asymptomatic and with no residual defects. Corrective repair of d-transposition of the great arteries and complete atrio-ventricular canal can be successfully achieved in this very challenging population during the neonatal period. PMID:17110123

  1. [Splenic artery aneurysms].

    Science.gov (United States)

    Colović, R; Davidović, L; Bilanović, D; Krivokapić, Z; Grubor, N; Cvetković, S; Radak, V; Marković, M

    2006-01-01

    Although the third most frequent aneurysm in the abdomen, after aneurysms of the aorta and iliac arteries, and most frequent aneurisms of visceral arteries, splenic artery aneurysms are rare, but not very rare. Thanks to the new imaging techniques, first of all ultrasonography, they have been discovered with increasing frequency. We present a series of 9 splenic artery aneurysms. Seven patients were female and two male of average age 49 years (ranging from 28 to 75 years). The majority of afected women were multiparae, with average 3 children (ranging from 1 to 6). One patient had a subacute rupture, and 2 had ruptures into the splenic vein causing portal hypertension. The spleen was enlarged in 7 out of 9 patients. The average size of aneurysms was 3,2 cm (ranging from 2 to 8 cm). The preoperative diagnosis of splenic artery aneurysm was established in 6 patients while in 3 patients aneurism was accidentally found during other operations, during splenectomy in 2, and during the excision of a retroperitoneal tumour in 1 patient. Aneurysmectomy was carried out in 7 patients, while a ligation of the incoming and outcoming wessels was performed in 2 patients with arteriovenous fistula. Splenectomy was performed in 6 patients, while pancreatic tail resection, cholecystectomy and excision of the retroperitoneal tumor were performed in 3 patients. Additional resection of the abdominal aortic aneurysm with reconstruction of aortoiliac segment was performed in 2 patients. There were no mortality and the postoperative recovery was uneventful in all patients. PMID:16989145

  2. 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 ...

  3. Operation Characteristics of Auxiliary Switch Controlling Close-open Time%用于金属短接时间控制的辅助开关操动特性研究

    Institute of Scientific and Technical Information of China (English)

    金立军; 张勇; 王珂; 张猛

    2011-01-01

    The close-open time of high voltage circuit breaker is a key parameter for affecting the breaking capacity. The reasonable control of close-open time has significant influence on breaking capacity of circuit breaker and safety of power grid. The structure of auxiliary switch of high-voltage circuit breaker was analyzed to put forward a proposal for controlling close-open time by auxiliary switch, establish a mathematical model to describe the auxiliary switch's operation characteristics and calculate the delay time, optimize the structure of controlling time delay which was based on theoretical analysis in this paper. The result of delay time is 16.63 ms, and the simulation of time delay characteristics is tested and verified by experiment finally.%高压断路器的金属短接时间是影响断路器开断能力的关键参量,直接影响断路器的关合和开断性能.合理控制金属短接时间对于保证断路器的开断能力以及整个电网的安全都有着重要的意义.通过分析高压断路器辅助开关的结构,提出了采用辅助开关实现的金属短接时间控制方案,建立了描述辅助开关操动特性的数学模型,并求解出延时时间为16.63ms,根据理论分析对延时控制机构进行了优化,辅助开关延时特性的仿真计算通过了实验验证.

  4. 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.

  5. Radiation hard vacuum switch

    Science.gov (United States)

    Boettcher, Gordon E.

    1990-01-01

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  6. Design of MEMS based `cross over junction' for T-type switch

    Science.gov (United States)

    Maninder, K.; Bansal, Deepak; Rangra, K. J.

    2016-04-01

    This paper presents a novel design approach of T-type RF MEMS switch cross over junction, implemented using symmetric toggle switch (STS) as a basic building block. T-type switches are key elements for designing redundancy switch matrices. Proposed design is a dual type switch, i.e. under operation same bridge is used as an ohmic series switch as well as a capacitive shunt switch. This reconfigurable switch constitutes the cross over junction part for the T-type switch. Simulated results show an insertion loss of resonant frequency is 3.253 KHz.

  7. 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.

  8. 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.

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

    Science.gov (United States)

    Ge, Jia; Fok, Mable P.

    2015-11-01

    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.

  10. A Control Method for Boost PFC Regulator Operating in DCM with Constant Switching Frequency*%一种Boost型PFC电路在DCM下的恒频控制方案

    Institute of Scientific and Technical Information of China (English)

    潘飞蹊; 涂祺铠; 梁昆凯; 敬守勇

    2011-01-01

    The average inductor current of a Boost converter operating in Discontinued Conduction Mode ( DCM ) is analyzed, and the mathematical relationship between the power switch turn-on-time and input-output voltage is found to guarantee that the converter operates with constant switching frequency as a Power Factor Correction ( PFC) regulator. Along with a practical circuit design, this paper proposes a PFC control method employing the sampling circuit of input-output voltage and a double integral circuit,with which the Boost converter can operate in DCM with constant switching frequency as a voltage follower. The theoretical analysis works out the boundary condition of the circuit control parameters. The measurement of the experimental circuit achieves near unit power factor and low current harmonic.%通过对Boost型变换器在不连续导电模式DCM(Discontinued Conduction Mode)下平均电感电流的分析,得到了在恒 频状态下实现功率因数校正 PFC ( Power Factor Correction)时,功率开关管所需的开启时间与输入、输出电压之间的数学关系,并结合实际电路设计,提出了一种PFC控制方案.该方案利用输入、输出电压的采样信号和一个二次积分电路来调制功率开 关管的开启时间,使Boost变换器在不连续导电模式下恒频工作并实现电压跟随.理论分析求解出了电路控制参量取值的边 界条件.实验电路测试获得了接近l的功率因数和很低的电流谐波含量.

  11. High power photoconductive semiconductor switches treated with amorphic diamond coatings

    International Nuclear Information System (INIS)

    Our recent efforts have resulted in implementation and demonstration of several intense photoconductively switched stacked Blumlein pulsers producing high power output pulses with risetimes as fast as 200 ps. A single GaAs photoconductive switch triggered with a low power laser diode array commutates these devices. During the avalanche-mode photoconductive switching of these pulsers at high powers, current filamentation associated with the high gain GaAs switches produces such high current density that switches are damaged near the metal-semiconductor interface and the lifetime is limited. This report presents progress toward improving the switch operation and lifetime by advanced treatments with the amorphic diamond coatings

  12. Switching overvoltages in offshore wind power grids

    DEFF Research Database (Denmark)

    Arana Aristi, Ivan

    offshore wind farms are shown together with simulation results. Switching operations in offshore wind power grids can be simulated with different electromagnetic transient programs. Different programs were used in the project and compared results are included in Chapter 4. Also in Chapter 4 different...... 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......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...

  13. Carotid Artery Screening

    Science.gov (United States)

    ... Resources Professions Site Index A-Z Carotid Artery Screening What is carotid artery screening? Who should consider ... about carotid artery screening? What is carotid artery screening? Screening examinations are tests performed to find disease ...

  14. 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.

  15. 46 CFR 169.681 - Disconnect switches and devices.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Disconnect switches and devices. 169.681 Section 169.681... Less Than 100 Gross Tons § 169.681 Disconnect switches and devices. (a) Externally operable switches or... supplies, means must be provided for locking the disconnect device in the “open” position. (c) For...

  16. Passively Q-switched Nd:YAG/Cr(4+):YAG bonded crystal microchip laser operating at 1112  nm and its application for second-harmonic generation.

    Science.gov (United States)

    Fu, S G; Ouyang, X Y; Liu, X J

    2015-10-10

    A passively Q-switched Nd:YAG/Cr4+:YAG microchip laser operating at 1112 nm is demonstrated. Under a pump power of 5.5 W, a maximum average output power of 623 mW was obtained with T=6% output coupler, corresponding to an optical-to-optical conversion efficiency of 11.3% and a slope efficiency of 19.5%. The minimum pulse width was 2.8 ns, the pulse energy and peak power were 39.3 μJ and 14 kW, respectively. Additionally, based on the 1112 nm laser, a 230 mW 556 nm green-yellow laser was achieved within an LBO crystal. PMID:26479822

  17. Active plasmonics in WDM traffic switching applications

    DEFF Research Database (Denmark)

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

    2012-01-01

    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......-enabling characteristics of active plasmonic circuits with an ultra-low power 3 response time product represents a crucial milestone in the development of active plasmonics towards real telecom and datacom applications, where low-energy and fast TO operation with small-size circuitry is targeted....

  18. 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.

  19. 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.

  20. Controller Architectures for Switching

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2009-01-01

    This paper investigate different controller architectures in connection with controller switching. The controller switching is derived by using the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization. A number of different architectures for the implementation of the YJBK parameterization are...... described and applied in connection with controller switching. An architecture that does not include inversion of the coprime factors is introduced. This architecture will make controller switching particular simple....

  1. MOSFET as a Switch

    OpenAIRE

    Dhaval Agrawal

    2014-01-01

    s as a switch. Also it shows the different problems and some remedy to solve those problems with equations and simulatis as a switch. Also it shows the different problems and some remedy to solve those problems with equations and simulatis as a switch. Also it shows the different problems and some remedy to solve those problems with equations and simulatis as a switch. Also it shows the different problems and some remedy to solve those problems with equations and simulatis as ...

  2. A Comparison of High-Voltage Switches

    Energy Technology Data Exchange (ETDEWEB)

    Chu, K.W.; Scott, G.L.

    1999-02-01

    This report summarizes our work on high-voltage switches during the past few years. With joint funding from the Department of Energy (DOE) and the Department of Defense (DOD), we tested a wide variety of switches to a common standard. This approach permitted meaningful comparisons between disparate switches. Most switches were purchased from commercial sources, though some were experimental devices. For the purposes of this report, we divided the switches into three generic types (gas, vacuum, and semiconductor) and selected data that best illustrates important strengths and weaknesses of each switch type. Test techniques that indicate the state of health of the switches are emphasized. For example, a good indicator of residual gas in a vacuum switch is the systematic variation of the switching delay in response to changes in temperature and/or operating conditions. We believe that the presentation of this kind of information will help engineers to select and to test switches for their particular applications. Our work was limited to switches capable of driving slappers. Also known as exploding-foil initiators, slappers are detonators that initiate a secondary explosive by direct impact with a small piece of matter moving at the detonation velocity (several thousands of meters per second). A slapper is desirable for enhanced safety (no primary explosive), but it also places extra demands on the capacitor-discharge circuit to deliver a fast-rising current pulse (greater than 10 A/ns) of several thousand amperes. The required energy is substantially less than one joule; but this energy is delivered in less than one microsecond, taking the peak power into the megawatt regime. In our study, the switches operated in the 1 kV to 3 kV range and were physically small, roughly 1 cm{sup 3} or less. Although a fuze functions only once in actual use, multiple-shot capability is important for production testing and for research work. For this reason, we restricted this report

  3. 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.

  4. Wide Bandgap Extrinsic Photoconductive Switches

    Science.gov (United States)

    Sullivan, James Stephen

    third generation vanadium compensated 6H-SiC has average impurity densities close to the recipe values. Extrinsic photoconductive switches constructed from the third generation vanadium compensated, 6H-SiC, 1 mm thick, 1 cm2, substrates have achieved high power operation at 16 kV with pulsed currents exceeding 1400 Amperes and a minimum on resistance of 1 ohm. The extrinsic photoconductive switch performance of the third generation 6H-SiC material was improved by a factor of up to 50 for excitation at the 532 nm wavelength compared to the initial 6H-SiC material. Switches based on this material have been incorporated into a prototype compact proton medical accelerator being developed by the Compact Particle Acceleration Corporation (CPAC). The vanadium compensated, 6H-SiC, extrinsic photoconductive switch operates differently when excited by 1064, or 532 nm, wavelength light. The 6H-SiC extrinsic photoconductive switch is a unipolar device when excited with 1064 nm light. The carriers are electrons excited from filled vanadium acceptor levels and other electron traps located within 1.17 eV of the conduction band. The switch is bipolar at 532 nm since the carriers consist of holes, as well as electrons. The holes are primarily generated by the excitation of valence band electrons into empty trap/acceptor levels and by two-photon absorption. Carrier generation by two-photon absorption becomes more important at high applied optical intensity at 532 nm and contributes to the supralinear behavior of switch conductance as a function of optical power. The 6H-SiC switch material is trap dominated at low nitrogen to vanadium ratios. The trap dominated vanadium compensated 6H-SiC exhibits low quantum efficiency when excited with 1064 and 532 nm light and has a carrier recombination time of ˜ 150 - 300 ps. The vanadium compensated 6H-SiC transitions to an impurity dominated material as the ratio of nitrogen to vanadium is increased to 0.5. The increased nitrogen doping produces a

  5. 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.

  6. 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.

  7. A solid-state dielectric elastomer switch for soft logic

    Science.gov (United States)

    Chau, Nixon; Slipher, Geoffrey A.; O'Brien, Benjamin M.; Mrozek, Randy A.; Anderson, Iain A.

    2016-03-01

    In this paper, we describe a stretchable solid-state electronic switching material that operates at high voltage potentials, as well as a switch material benchmarking technique that utilizes a modular dielectric elastomer (artificial muscle) ring oscillator. The solid-state switching material was integrated into our oscillator, which self-started after 16 s and performed 5 oscillations at a frequency of 1.05 Hz with 3.25 kV DC input. Our materials-by-design approach for the nickel filled polydimethylsiloxane based switch has resulted in significant improvements over previous carbon grease-based switches in four key areas, namely, sharpness of switching behavior upon applied stretch, magnitude of electrical resistance change, ease of manufacture, and production rate. Switch lifetime was demonstrated to be in the range of tens to hundreds of cycles with the current process. An interesting and potentially useful strain-based switching hysteresis behavior is also presented.

  8. Coronary artery dissection by an oversized balloon.

    Science.gov (United States)

    Yafi, Wael; Jacquemin, Laurent

    2014-01-01

    Percutaneous coronary intervention (PCI) as a treatment of coronary artery disease can be a simple, rapid procedure with a clear benefit for the patient, but it could also become a complex procedure with fatal consequences. These complications depend on the lesion itself, material used and also on operating staff. In this case we report a coronary artery dissection of the circumflex (CX) artery caused by inflation of an oversized balloon. We discuss here the management and evolution of this complication. PMID:25479753

  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... TRAFFIC OPERATIONS DESIGN-BUILD CONTRACTING General § 636.118 Is team switching allowed after contract...-builder, team member switching (adding or switching team members) is discouraged after contract...

  10. Soft Switching SEPP High Frequency Inverter for Induction Heating

    Science.gov (United States)

    Ogiwara, Hiroyuki; Nakaoka, Mutsuo

    This paper presents a novel circuit topology to attain soft switching operation of a high frequency inverter. Its output power is regulated over a wide range using a PWM control technique by connecting an auxiliary resonant circuit to the conventional single ended push pull (SEPP) high frequency inverter for induction heating. All switching devices in the proposed inverter are operated soft switching mode. This paper describes its circuit constitution and obtained experimental results from a practical point of view.

  11. Angioplasty and stent placement -- peripheral arteries

    Science.gov (United States)

    Percutaneous transluminal angioplasty - peripheral artery; PTA - peripheral artery; Angioplasty - peripheral arteries; Iliac artery -angioplasty; Femoral artery - angioplasty; Popliteal artery - angioplasty; Tibial ...

  12. 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.)

  13. 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.

  14. DISCUSSION ON RUNNING OF SWITCH OPERATION BETWEEN TWO CRUDE MATERIALS FOR HYDROGENATION UNIT OF SPECIAL OIL%特种油加氢装置两种原料切换操作运行探讨

    Institute of Scientific and Technical Information of China (English)

    韦节银

    2015-01-01

    介绍特种油加氢装置运转情况和产品质量,同时介绍了利用该装置加工5#白油料的运转和产品质量改善情况。结果表明,以直馏常二线组分为原料加氢生产的清洁溶剂油产品质量优良;以5#白油料为原料加氢生产的润滑油基础油产品质量关键指标优于Ⅱ类或Ⅱ+类基础油产品指标要求,达到了升级换代的目的。两种原料切换操作,避免了因频繁停工造成的能耗和操作费用的浪费,提高了装置经济效益。%Running situation and product quality of the hydrogenation unit for special oil, improvement on operation and product quality of the unit which was used to process No.5 white oil material were introduced.The results showed that product quality of the clean solvent oil was good with direct straight distillation component from the second atmospheric line as hydrogena-tion feed.Key indexed of the product quality for lubricant base oil with No.5 white oil material as hydrogenation feed were better than that ofⅡandⅡ+types of base oil, which obtained the purpose of the upgrading of product.Waste on energy consumption and operation cost causing by frequent downtimes was prevented and economic profit of the unit was raised by means of switch operation between two crude materials.

  15. The Robustness of Stochastic Switching Networks

    OpenAIRE

    Loh, Po-Ling; Zhou, Hongchao; Bruck, Jehoshua

    2009-01-01

    Many natural systems, including chemical and biological systems, can be modeled using stochastic switching circuits. These circuits consist of stochastic switches, called pswitches, which operate with a fixed probability of being open or closed. We study the effect caused by introducing an error of size ∈ to each pswitch in a stochastic circuit. We analyze two constructions – simple series-parallel and general series-parallel circuits – and prove that simple series-parallel circuits are robus...

  16. Multiserver switch scheduling for high speed optical switches

    Science.gov (United States)

    Golla, Prasad; Blanton, John; Damm, Gerard

    2003-10-01

    A switch matrix implemented as an optical crossbar using semiconductor optical amplifiers is able to accommodate extreme concentrations of data traffic. Due to the need to reduce optical guard band overhead it is beneficial to switch fixed size bursts of data cells on a time slot basis. The high capacity of the optical matrix supports multiple optical ports per burst card, and the implementation of multiple queue servers per burst card helps make better use of the multiplicity of ports. Problems associated with arbitrating multiple ports and multiple servers per burst card have been resolved by extending the operation of existing iterative, single server scheduling algorithms. The multiserver arbitration time will be in proportion to the number of servers -- corresponding to the channels of DWDM link -- unless a reconciliation stage is used after each iteration when an arbiter per server is used. The reconciliation stage sets the problem of broken data dependencies between server arbitrations in this case. Further, to address the time limitations for computing the scheduling solution, parallel arbiter implementations have been developed and tested against single arbiter designs. Again, the broken dependencies between iterations of an arbitration are addressed through the use of a grant reconciliation stage. The use of multiple queue servers per burst card also resolves some of the data loss problems related to polarized traffic. Simulations of the multiple server and parallel arbiter implementations have demonstrated their efficiency compared to previous implementations. Compounded to this problem is maintaining high throughput of the switch matrix while observing data transit time limits. This involves balancing two contradictory requirements; switch or line card efficiency and data transit times. To improve efficiency it is desirable to transmit only full packets. However, to prevent loss of data due to timeout it will be necessary to transmit some incomplete

  17. 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

  18. Haemodynamic optimisation in lower limb arterial surgery

    DEFF Research Database (Denmark)

    Bisgaard, J; Gilsaa, T; Rønholm, E;

    2012-01-01

    -operative complications and shorten hospital length of stay after open elective lower limb arterial surgery. METHODS: Forty patients scheduled for open elective lower limb arterial surgery were prospectively randomised. The LiDCO™plus system was used for haemodynamic monitoring. In the intervention group, stroke volume...

  19. Carotid Artery Disease

    Science.gov (United States)

    ... brain with blood. If you have carotid artery disease, the arteries become narrow, usually because of atherosclerosis. ... one of the causes of stroke. Carotid artery disease often does not cause symptoms, but there are ...

  20. 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 ...

  1. 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...... strategies -- Mode combination strategies -- Internationalization, international strategies and FOMs -- Conclusion -- Conclusions and recommendations...

  2. Introduction to Optical Burst Switching

    OpenAIRE

    KERNÁCS János; SZILÁGYI Szabolcs

    2010-01-01

    Optical Burst Switching (OBS) isconsidered a popular switching paradigm for therealization of all-optical networks due to the balance itoffers between the coarse-grained Optical CircuitSwitching (OSC) and fine-grained Optical PacketSwitching (OPS). Given that the data are switched allopticallyat the burst level, Optical Burst Switchingcombines the transparency of Optical CircuitSwitching with the benefits of statistical multiplexingin Optical Packet Switching.

  3. 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...

  4. Early outcomes of laparoscopic donor nephrectomy with multiple renal arteries

    Directory of Open Access Journals (Sweden)

    Fernando Meyer

    2012-08-01

    Full Text Available PURPOSE: We evaluated our experience with laparoscopic donor nephrectomy in patients with multiple renal arteries, comparing operative outcomes and early graft function with patients with a single renal artery. MATERIALS AND METHODS: From January 2003 to February 2009, 130 patients underwent laparoscopic donor nephrectomy at our institution, 108 (83% with a single renal artery and 22 (17% with multiple arteries. Donor and recipient outcomes for single artery and multiple arteries allografts were compared. RESULTS: The LDN operative time was similar between the single artery and multiple arteries groups (162 vs 163 min, respectively, p = 0.87. Allografts with multiple arteries had significantly longer warm ischemia time (3.9 vs 4.9 min, p = 0.05 and cold ischemia time (72 vs 94 min, p < 0.001 than those with single artery. The conversion rate was similar between single and multiple arteries groups (6% vs 4.5%, respectively, p = 0.7. Multiple arteries grafts had a non statistically significant higher rate of poor graft function when compared to single artery grafts (23% vs 12%, respectively, p = 0.18. Five patients in the single artery group (4.6% and one patient in the multiple arteries group (4.5% needed dialysis during the first postoperative week. Overall, recipient complication rates were similar between single and multiple arteries groups (12.9% vs 18.1%, respectively, p = 0.51. CONCLUSION: Laparoscopic donor nephrectomy with multiple arteries was associated with a non statistically significant higher rate of poor early graft function. The procedure appears to be safe in patients with multiple arteries, with similar complications rates. Multiple arteries should not be a contraindication for laparoscopic donor nephrectomy.

  5. 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

  6. Stochastic Switching Circuit Synthesis

    OpenAIRE

    Wilhelm, Daniel; Bruck, Jehoshua

    2009-01-01

    Shannon in his 1938 Masterpsilas Thesis demonstrated that any Boolean function can be realized by a switching relay circuit, leading to the development of deterministic digital logic. Here, we replace each classical switch with a probabilistic switch (pswitch). We present algorithms for synthesizing circuits closed with a desired probability, including an algorithm that generates optimal size circuits for any binary fraction. We also introduce a new duality property for series-parallel stocha...

  7. 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.

  8. 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.

  9. Total Arterial Revascularisation in Left Ventricular Dysfunction

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The feasibility and safety of total arterial coronary revascularization with 2 arterial conduits in patients with impaired left ventricular function was evaluated. Data were prospectively collected on all patients with multiple vessel disease and moderately or severely impaired left ventricular function, who underwent coronary surgery with the intention of total arterial revascularization with 2 conduits between March 1995 and August 2002. One hundred and seventy-nine patients were included in the study. Acute coronary insufficiency was present in 3 patients and 43 had unstable angina. Severe left ventricular impairment was present in 29 patients. There were 17 redo operations including 3 redo-redo procedures. Eighty-two percent of patients had a Y graft configuration from the left internal mammary artery (right internal mammary artery 40. 8 %, radial artery 33.5 %,other 7.8 % ). The perioperative mortality was 2.2 %, myocardial infarction 1.7 % and stroke 0. 6 %.Total arterial revascularization in patients with ischaemic left ventricular dysfunction can be safely performed with 2 arterial conduits. The radial artery provides conduit length greater than the right internal mammary artery and allows full revascularization despite left ventricular dilatation.

  10. 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.

  11. Quasi-parallel resonant DC-link inverter with a reduced switch voltage stress

    International Nuclear Information System (INIS)

    This paper presents a new soft switching inverter with DC-link switch and one auxiliary switch. The important feature of this topology is that the switches voltage stress is lower than that of other quasi-parallel resonant DC-link inverters. All diodes and switches are turned on and off under soft switching conditions. Auxiliary switch is turned on and off under zero current switching conditions, and the DC-link switch is turned on under zero voltage zero current switching condition and turned off under zero voltage switching condition. The proposed converter is analyzed and its operating modes are explained in details. The presented experimental results of a prototype converter confirm the theoretical analysis.

  12. Quasi-parallel resonant DC-link inverter with a reduced switch voltage stress

    Energy Technology Data Exchange (ETDEWEB)

    Madani, Seyed M., E-mail: madani@cc.iut.ac.i [Department of Electrical and Computer Engineering, Isfahan University of Technology (Iran, Islamic Republic of); Amini, Mohammad Reza, E-mail: mrezaaminy@ec.iut.ac.i [Department of Electrical and Computer Engineering, Isfahan University of Technology (Iran, Islamic Republic of); Atighechi, Hamid, E-mail: h.atighechi@gmail.co [Department of Electrical and Computer Engineering, Isfahan University of Technology (Iran, Islamic Republic of); Dolatshahi, Milad, E-mail: dolatshahi@ec.iut.ac.i [Department of Electrical and Computer Engineering, Isfahan University of Technology (Iran, Islamic Republic of)

    2011-01-15

    This paper presents a new soft switching inverter with DC-link switch and one auxiliary switch. The important feature of this topology is that the switches voltage stress is lower than that of other quasi-parallel resonant DC-link inverters. All diodes and switches are turned on and off under soft switching conditions. Auxiliary switch is turned on and off under zero current switching conditions, and the DC-link switch is turned on under zero voltage zero current switching condition and turned off under zero voltage switching condition. The proposed converter is analyzed and its operating modes are explained in details. The presented experimental results of a prototype converter confirm the theoretical analysis.

  13. 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...

  14. Asymmetrical Switch Costs in Children

    Science.gov (United States)

    Ellefson, Michelle R.; Shapiron, Laura R.; Chater, Nick

    2006-01-01

    Switching between tasks produces decreases in performance as compared to repeating the same task. Asymmetrical switch costs occur when switching between two tasks of unequal difficulty. This asymmetry occurs because the cost is greater when switching to the less difficult task than when switching to the more difficult task. Various theories about…

  15. 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.

  16. TECAB - Totally Endoscopic Coronary Artery Bypass

    Medline Plus

    Full Text Available ... the sternum and cannulate the aorta and the right atrium. In this operation, since we are not ... exactly perpendicular to the camera port here. All right. The femoral artery will be used to give ...

  17. Controllable Passively Q-Switched Laser

    Institute of Scientific and Technical Information of China (English)

    YANG Cheng-Wei; HUO Yu-Jing; HE Shu-Fang; YIN Xiao-Dong; ZHANG Bao-Shun

    2005-01-01

    @@ We present a novel kind of pulsed laser named controllable passively Q-switched laser (CPQL). A CPQL of Nd:YVO4 with Cr:YAG as saturable absorber was demonstrated and studied as an example of the kind of pulsed lasers. In CPQL, as the actively controlling signal, a diode laser beam was focused onto the saturable absorber in the resonant cavity of the passively Q-switched laser (PQL) and was absorbed by the absorber to realize the active control of the CPQL. The characters of the CPQL output laser pulses, such as generation time, repetition rate, pulse width, peak power and energy per pulse, can be controlled by the operator. The CPQLs possess the advantages of both passively Q-switched laser and actively Q-switched 1aser. Because of their compactness, low cost and controllability, the CPQLs will find wide applications in many fields.

  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. Multidimensional set switching.

    Science.gov (United States)

    Hahn, Sowon; Andersen, George J; Kramer, Arthur F

    2003-06-01

    The present study examined the organization of preparatory processes that underlie set switching and, more specifically, switch costs. On each trial, subjects performed one of two perceptual judgment tasks, color or shape discrimination. Subjects also responded with one of two different response sets. The task set and/or the response set switched from one to the other after 2-6 repeated trials. Response set, task set, and double set switches were performed in both blocked and randomized conditions. Subjects performed with short (100-msec) and long (800-msec) preparatory intervals. Task and response set switches had an additive effect on reaction times (RTs) in the blocked condition. Such a pattern of results suggests a serial organization of preparatory processes when the nature of switches is predictable. However, task and response set switches had an underadditive effect on RTs in the random condition when subjects performed with a brief cue-to-target interval. This pattern of results suggests overlapping task and response set preparation. These findings are discussed in terms of strategic control of preparatory processes in set switching. PMID:12921431

  20. 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.).

  1. A Low Cost Single-Switch Bridgeless Boost PFC Converter

    Directory of Open Access Journals (Sweden)

    Younghoon Cho

    2014-03-01

    Full Text Available This paper proposes the single-switch bridgeless boost power factor correction (PFC converter to achieve high efficiency in low cost. The proposed converter utilizes only one active switching device for PFC operation as well as expecting higher efficiency than typical boost PFC converters. On the other hand, the implementation cost is less than traditional bridgeless boost PFC converters, in where two active switching deivces are necessary. The operational principle, the modeling, and the control scheme of the proposed converter are discussed in detail. In order to verify the operation of the proposed converter, a 500W switching model is built in PSIM software package. The simulation results show that the proposed converter perfectly achieves PFC operation with only a single active switch.

  2. New fast switches for the Tore Supra ohmic heating circuit

    International Nuclear Information System (INIS)

    The Tore-Supra ohmic heating circuit is equipped with four fast make switches and one fast opening switch. After many years of operation, it became necessary to substitute this equipment by modern components with similar ratings. An extensive research has been undertaken to find fast switches able to withstand more than 2500 operations per year without maintenance, at a make current of 54 kA, a voltage of 12 kV and with a closing time of less than 15 ms. At the end of the investigation, it was decided to replace the old components by fast mechanical switches proposed by the Efremov Institute and based on a prototype developed for ITER. This paper presents the technical requirements and the characteristics of the switches and describes the operational experience gained with these components during operating campaigns of 2002 and 2003. (authors)

  3. 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.

  4. 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.

  5. 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

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

    OpenAIRE

    Bahador Fani; Majid Delshad; Daryoosh Nazarpour

    2010-01-01

    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 compu...

  7. 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.

  8. Coating possibilities for magnetic switches

    International Nuclear Information System (INIS)

    High average power magnetic pulse compression systems are now being considered for use in several applications such as the High Power Radiation Source (HiPoRS) project. Such systems will require high reliability magnetic switches (saturable inductors) that are very efficient and have long lifetimes. One of the weakest components in magnetic switches is their interlaminar insulation. Considerations related to dielectric breakdown, thermal management of compact designs, and economical approaches for achieving these needs must be addressed. Various dielectric insulation and coating materials have been applied to Metglas foil in an attempt to solve the complex technical and practical problems associated with large magnetic switch structures. This work reports various needs, studies, results, and proposals in selecting and evaluating continuous coating approaches for magnetic foil. Techniques such as electrophoretic polymer deposition and surface chemical oxidation are discussed. We also propose continuous photofabrication processes for applying dielectric ribs or spacers to the foil which permit circulation of dielectric liquids for cooling during repetitive operation. 10 refs., 8 figs., 11 tabs

  9. [Trapped popliteal vein and artery].

    Science.gov (United States)

    Allal, J; Gallimard, J F; Goubbault, F; Lelong, J; Barbier, J; Barraine, R

    1986-03-01

    A report is made of 3 observations of vascular constrictions in the knee hollow of three young adults: two constrictions of the popliteal artery, one by abnormal insertion of a tendon of the gastrocnemius muscle and of the arterial passage, the other by a fibrous band surrounding the artery. In one observation, the disorder was revealed by acute ischemia of one limb. The third observation was of a sural phlebitis with secondary repetition at the constriction of the popliteal vein by Soleaire's arcade. In all cases examination using the Doppler effect, in baseline and especially dynamic position, gives a diagnosis and allows postoperative monitoring. Bilateral arteriography, both static and dynamic, allows a precise diagnosis to be given and reveals the extent of vascular lesions, which conditions the operative technique. Treatment is always surgical, with exploration of the contralateral side if a constriction is suspected, even if it is asymptomatic. PMID:3707018

  10. 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...

  11. 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

  12. Switch mode power supply

    International Nuclear Information System (INIS)

    This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

  13. SPARK GAP SWITCH

    Science.gov (United States)

    Neal, R.B.

    1957-12-17

    An improved triggered spark gap switch is described, capable of precisely controllable firing time while switching very large amounts of power. The invention in general comprises three electrodes adjustably spaced and adapted to have a large potential impressed between the outer electrodes. The central electrode includes two separate elements electrically connected togetaer and spaced apart to define a pair of spark gaps between the end electrodes. Means are provided to cause the gas flow in the switch to pass towards the central electrode, through a passage in each separate element, and out an exit disposed between the two separate central electrode elements in order to withdraw ions from the spark gap.

  14. 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.

  15. 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.

  16. [Abnormal popliteal arteries].

    Science.gov (United States)

    Elbaz, C

    1975-01-01

    Arteriopathy restricted to the popliteal artery, except in cases of atheroma, must indicate three of four unusual diagnoses: the trapped popliteal artery and the dessicating haematoma are anatomo-clinical entities that have been identified only relatively recently. The popliteal artery may be trapped by the medial gastrocnomius muscle, round the tendon of which the artery passes (totally or partially). This results in compression of the artery and eventually in thrombosis. Clinically, intermittent claudication is seen that may deteriorate and lead to gangrene of the toes. Arteriography makes it possible to diagnose the condition as the condition as the artery is considerably displaced inwards. Surgical correction is simple: sectioning of the tendon and repositioning of the artery. Dessicating haematoma of the popliteal artery is due essentially to atheroma, associated with medianecrosis. A "egg-timer" stenosis is found by arteriography and this condition also progresses towards thrombosis. Arterial restoration is called for, usually by bridging. PMID:1230799

  17. 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.

  18. Plasmonic enhanced ultrafast switch.

    Energy Technology Data Exchange (ETDEWEB)

    Subramania,Ganapathi Subramanian; Reno, John Louis; Passmore, Brandon Scott; Harris, Tom.; Shaner, Eric Arthur; Barrick, Todd A.

    2009-09-01

    Ultrafast electronic switches fabricated from defective material have been used for several decades in order to produce picosecond electrical transients and TeraHertz radiation. Due to the ultrashort recombination time in the photoconductor materials used, these switches are inefficient and are ultimately limited by the amount of optical power that can be applied to the switch before self-destruction. The goal of this work is to create ultrafast (sub-picosecond response) photoconductive switches on GaAs that are enhanced through plasmonic coupling structures. Here, the plasmonic coupler primarily plays the role of being a radiation condenser which will cause carriers to be generated adjacent to metallic electrodes where they can more efficiently be collected.

  19. Radial Plasma Flow Switch on GIT-12 Generator

    Science.gov (United States)

    Chaikovsky, S. A.; Kokshenev, V. A.; Rousskikh, A. G.; Shishlov, A. V.; Fedunin, A. V.; Labetsky, A. Yu.; Kurmaev, N. E.; Fursov, F. I.

    2006-01-01

    The preliminary experiments were performed on wire array implosion driven by a radial plasma flow switch on the GIT-12 generator operating in a microsecond mode. Imploding gas puff z-pinch plasma was used to provide fast switching of the current to an aluminum wire array. The experimental results are presented in the paper.

  20. 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...

  1. 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 236.732 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.732 Controller, circuit; switch. A device for opening and closing electric circuits, operated by...

  2. 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...

  3. 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.

  4. [Popliteal artery entrampment: report of one case].

    Science.gov (United States)

    Parra, Juan; Corvalán, Felipe; Ibáñez, Fernando; Bianchi, Víctor; Bastías, Waldo; Salas, Cristian; Cam, Alfredo; Lamarca, Andrés

    2006-02-01

    Popliteal artery entrampment is a rare condition, occurring in young subjects, that causes ischemia of the extremity. The anatomical background is the compression or occlussion of the popliteal artery caused by forced plantar or dorsal flexion. We report a 32 year-old sportsman who presented with gangrene of the right first toe and a history of three months of progressive claudication. The Ankle-Brachial index and pulse volume curve registries showed a severe ischemia below the knee. Angiography showed a medial deviation of the popliteal artery associated to stenosis and aneurysm formation. A CT scan of the contralateral artery was normal. The patient was operated using a posterior approach, performing a reverse saphenous vein bypass graft and excising the popliteal artery. The postoperative period was uneventful. PMID:16554929

  5. Switch Attention to Listen

    OpenAIRE

    Dhamani, Imran; Leung, Johahn; Carlile, Simon; Sharma, Mridula

    2013-01-01

    The aim of this research was to evaluate the ability to switch attention and selectively attend to relevant information in children (10–15 years) with persistent listening difficulties in noisy environments. A wide battery of clinical tests indicated that children with complaints of listening difficulties had otherwise normal hearing sensitivity and auditory processing skills. Here we show that these children are markedly slower to switch their attention compared to their age-matched peers. T...

  6. Switching to Photonics

    OpenAIRE

    Hinton, Harvard S.

    1992-01-01

    The use of hardware that exploits the interplay of photons and electrons to switch voice, data, and video is discussed. The two directions being taken by current research-guided-wave and free-space photonics-are examined. Photonic time-slot interchanges are described. Multidivisional fabrics, based on a combination of space-division and time-division multiplexing, are considered, as is the wavelength-division-based photonic packet switch, another kind of multidimensional fabric. The use of se...

  7. 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.

  8. 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.

  9. Ferroelectric switching of elastin

    OpenAIRE

    Liu, Yuanming; Cai, Hong-Ling; Zelisko, Matthew; WANG, YUNJIE; Sun, Jinglan; Yan, Fei; Ma, Feiyue; Wang, Peiqi; Chen, Qian Nataly; Zheng, Hairong; Meng, Xiangjian; SHARMA, PRADEEP; Zhang, Yanhang; Li, Jiangyu

    2014-01-01

    Ferroelectricity has long been speculated to have important biological functions, although its very existence in biology has never been firmly established. Here, we present, to our knowledge, the first macroscopic observation of ferroelectric switching in a biological system, and we elucidate the origin and mechanism underpinning ferroelectric switching of elastin. It is discovered that the polarization in elastin is intrinsic at the monomer level, analogous to the unit cell level polarizatio...

  10. Finding a stabilising switching law for switching nonlinear models

    Science.gov (United States)

    Lendek, Zs.; Raica, P.; Lauber, J.; Guerra, T. M.

    2016-09-01

    This paper considers the stabilisation of switching nonlinear models by switching between the subsystems. We assume that arbitrary switching between two subsystems is possible once a subsystem has been active for a predefined number of samples. We use a Takagi-Sugeno representation of the models and a switching Lyapunov function is employed to develop sufficient stability conditions. If the conditions are satisfied, we construct a switching law that stabilises the system. The application of the conditions is illustrated in several examples.

  11. 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....

  12. 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.

  13. 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.

  14. Optical switching systems using nanostructures

    DEFF Research Database (Denmark)

    Stubkjær, Kristian

    2004-01-01

    High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems.......High capacity multiservice optical networks require compact and efficient switches. The potential benefits of optical switch elements based on nanostructured material are reviewed considering various material systems....

  15. Understanding and Supporting Window Switching

    NARCIS (Netherlands)

    Tak, S.

    2011-01-01

    Switching between windows on a computer is a frequent activity, but finding and switching to the target window can be inefficient. This thesis aims to better un-derstand and support window switching. It explores two issues: (1) the lack of knowledge of how people currently interact with and switch b

  16. Switching Control for Adaptive Disturbance Attenuation

    NARCIS (Netherlands)

    Battistelli, Giorgio; Mari, Daniele; Selvi, Daniela; Tesi, Alberto; Tesi, Pietro

    2014-01-01

    The problem of adaptive disturbance attenuation is addressed in this paper using a switching control approach. A finite family of stabilizing controllers is pre-designed, with the assumption that, for any possible operating condition, at least one controller is able to achieve a prescribed level of

  17. 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.

  18. Development of a biochemical switching device: mathematical model.

    Science.gov (United States)

    Okamoto, M

    1990-01-01

    There are many examples of enzymes that share substrates or cofactors in a cyclic manner. Techniques have been developed that use cyclic enzyme systems to assay quantitatively small amounts of biochemical substances (cofactor, substrate), however, only a few studies of the control of these systems have been published. The author previously showed with computer simulations that cyclic enzyme systems have the reliability of ON-OFF types of operation (McCulloch-Pitts' neuronic equation) and the applicability for a switching circuit in a biocomputer. The switching time was inevitably determined in accordance with the difference in amount between two inputs of the system. A unique switching mechanism of cyclic enzyme systems (basic switching element) and the effects of excitatory stimuli on switching properties of the integrated biochemical switching system are demonstrated. PMID:2082931

  19. Photoconductive switch enhancements for use in Blumlein pulse generators

    International Nuclear Information System (INIS)

    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

  20. 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.

  1. Intelligent switches of integrated lightwave circuits with core telecommunication functions

    Science.gov (United States)

    Izhaky, Nahum; Duer, Reuven; Berns, Neil; Tal, Eran; Vinikman, Shirly; Schoenwald, Jeffrey S.; Shani, Yosi

    2001-05-01

    We present a brief overview of a promising switching technology based on Silica on Silicon thermo-optic integrated circuits. This is basically a 2D solid-state optical device capable of non-blocking switching operation. Except of its excellent performance (insertion lossmarket segments appropriate for the switch size and technology, followed by a discussion of the basic features of the technology. The discussion is focused on important requirements from the switch and the technology (e.g., insertion loss, power consumption, channel isolation, extinction ratio, switching time, and heat dissipation). The mechanical design is also considered. It must take into account integration of optical fiber, optical planar wafer, analog electronics and digital microprocessor controls, embedded software, and heating power dissipation. The Lynx Photon.8x8 switch is compared to competing technologies, in terms of typical market performance requirements.

  2. 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

  3. A case of William's syndrome associated peripheral pulmonary arterial stenosis

    International Nuclear Information System (INIS)

    William's syndrome, in order to more completely delineate the total spectrum of the disorder, indicates that 'infantile hypercalcemia', 'peculiar facies' and 'supravalvular aortic stenosis.' In has other many vascular anomalies, such as peripheral pulmonary arterial stenosis, coronary arterial stenosis, celiac arterial stenosis, and renal aterial stenosis. Only 32% of the patients have evidence of supravalvular aortic stenosis. And it is very rare disease entity that has been reported rarely in Korea. Recently authors experienced a case that was questioned William's syndrome with peripheral pulmonary arterial stenosis, clinically and preliminary radiologically and this case was confirmed by operation. Here we report a case of William's syndrome with peripheral pulmonary arterial stenosis and reviewed literatures

  4. 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.

  5. Combination of Rare Right Arterial Variation with Anomalous Origins of the Vertebral Artery, Aberrant Subclavian Artery and Persistent Trigeminal Artery

    Science.gov (United States)

    Ishihara, H.; San Millán Ruíz, D.; Abdo, G.; Asakura, F.; Yilmaz, H.; Lovblad, K.O.; Rüfenacht, D.A.

    2011-01-01

    Summary A 32-year-old woman hospitalized for subarachnoid hemorrhage showed rare arterial variation on the right side with anomalous origins of the vertebral artery, aberrant subclavian artery and persistent trigeminal artery. Angiography showed the right vertebral artery to originate from the right common carotid artery, the right subclavian artery to arise separately from the descending aorta, and persistent trigeminal artery on the right side. The possible embryonic mechanism of this previously unreported variant combination is discussed. PMID:22005696

  6. On Renal Artery Stenosis

    OpenAIRE

    Eklöf, Hampus

    2005-01-01

    Renal artery stenosis (RAS) is a potentially curable cause of hypertension and azotemia. Besides intra-arterial renal angiography there are several non-invasive techniques utilized to diagnose patients with suspicion of renal artery stenosis. Removing the stenosis by revascularization to restore unobstructed blood flow to the kidney is known to improve and even cure hypertension/azotemia, but is associated with a significant complication rate. To visualize renal arteries with x-ray technique...

  7. Retinal artery occlusion

    Science.gov (United States)

    ... artery occlusion; Branch retinal artery occlusion; CRAO; BRAO Images Retina References Sanborn GE, Magargal LE. Arterial obstructive disease ... A.M. Editorial team. Related MedlinePlus Health Topics ... audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among ...

  8. Reversible Chemisorption Gas-Gap Thermal Switch

    Science.gov (United States)

    Jones, Jack A.; Bard, Steven; Blue, Gary

    1991-01-01

    Gas/sorbent combinations provide means to turn heat-conduction paths on and off. Single-stage gas-gap thermal switch based on reversible chemisorption of hydrogen gas by ZrNiH. Two-stage gas-gap thermal switch based on reversible desorption of O2 from MnO2 in first stage, followed by absorption in Cu on zeolite in second stage. Requires relatively low power. Used in sorption refrigeration systems designed to operate for long times without maintenance.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Comparison of Standard Catheters Versus Radial Artery-Specific Catheter in Patients Who Underwent Coronary Angiography Through Transradial Access.

    Science.gov (United States)

    Chen, On; Goel, Sunny; Acholonu, Michael; Kulbak, Guy; Verma, Shivani; Travlos, Efstratios; Casazza, Richard; Borgen, Elliot; Malik, Bilal; Friedman, Michael; Moskovits, Norbert; Frankel, Robert; Shani, Jacob; Ayzenberg, Sergey

    2016-08-01

    In this prospective, randomized controlled study, we aim to compare the performance outcomes of standard catheters with the radial artery-specific catheter. Over the past decade, transradial cardiac catheterization has gained widespread popularity because of its low complication rates compared with transfemoral access. Operators have the choice of using either standard catheters (used for both transfemoral and transradial approach, with need for separate catheter use for either right or left coronary artery engagement) or a dedicated radial artery catheter, which is specifically designed to engage both coronary arteries through radial artery access. A total of 110 consecutive patients who underwent coronary angiography at our institution from March 2015 to April 2015 were prospectively randomized to either radial artery-specific Tiger catheter (5Fr; Terumo Interventional Systems, Somerset, New Jersey) versus standard Judkins left and right catheters (5Fr R4, L4; Cordis Corporation, Miami, Florida). The end points of the study included fluoroscopy time, dose-area product, contrast volume used, and total procedure time for the coronary angiography. A total of 57 patients (52%) were randomized to radial artery-specific catheter and 53 (48%) to the standard catheter. Tiger catheter was associated with significantly lower fluoroscopy time (184 ± 91 vs 238 ± 131 seconds, p = 0.015), which was statistically significant. Other outcome measures such as dose-area product (2,882.4 ± 1,471.2 vs 3,524.6 ± 2,111.7 Gy·cm(2), p = 0.07), total contrast volume (48.1 ± 16.1 vs 53.4 ± 18.5 ml, p = 0.114), and total procedure time (337 ± 382 vs 434 ± 137 seconds, p = 0.085) were also lower in single-catheter group, but it did not reach statistical significance. A total of 8 patients (14%) were crossed over from radial-specific catheter arm to standard catheter arm because of substandard image quality and difficulty in coronary engagement. Six patients had to be

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

    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

    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幅值有所减小.对GIS管壳附近的空间电磁场进行了测量,计算结果与现场实测数据基本相符.%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

  16. Anterior communicating artery aneurysm associated with an infraoptic course of anterior cerebral artery and rare variant of the persistent trigeminal artery: a case report and literature review.

    Science.gov (United States)

    Turkoglu, Erhan; Arat, Anıl; Patel, Nirav; Kertmen, Hayri; Başkaya, Mustafa K

    2011-05-01

    Infraoptic course of the precommunicating segment of the anterior cerebral artery (A1) is a rare anomaly. Furthermore, the presence of this anomaly associated with persistent trigeminal artery variant has been reported in the literature only once. We present a patient who had infraoptic course of A1 associated with an ipsilateral persistent trigeminal artery variant arising from the right internal carotid artery with no apparent connection to the basilar artery. The persistent trigeminal artery variant supplied to the right posteroinferior cerebellar artery territory. The patient also had hypoplastic left vertebral artery, superior cerebellar arteries originating from posterior cerebellar arteries bilaterally, and a bilobed aneurysm of the anterior communicating artery. The aneurysm was clipped and the infraoptic course was verified during the surgery. The post-operative course was uneventful and a follow-up arteriogram on the 7th postoperative day revealed successful obliteration of the aneurysm. We reviewed the literature with respect to presentation, associated vascular anomalies, imaging, associated cerebral aneurysms and other cerebral abnormalities, and treatment of the associated aneurysms. A discussion of the embryogenesis of this rare anomaly is also provided. PMID:21269759

  17. 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.

  18. Plasma opening switch experiments on supermite

    International Nuclear Information System (INIS)

    Experiments using plasma opening switches with fast field coils and plasmas injected on slow magnetic fields are described. Data showing the measurement of the field penetration into the volume that initially held the plasma fill will be shown. Assuming the plasma is mostly pushed back from the coil, rather than being penetrated by the magnetic field allows the density to be calculated, and gives densities of a few times 1013 cm-3 for our usual operating range. The data makes it clear that the switch is open well before the initial plasma volume is completely penetrated by the magnetic fields. Additional measurements relating to the magnetic field penetration distance and physical penetration mechanism are presented. Other data presented show a magnetic insulation problem which must be solved before very large voltage multiplication can be accomplished with sufficient switch efficiency

  19. Opening switch technology for pulsed power systems

    International Nuclear Information System (INIS)

    Opening switches are useful for converting a slow pulse power to faster delivery. Its requirement becomes critical when using inductive energy storage systems in pulse power applications. Inductive storage has advantage over usual capacitor bases systems by way of its high energy density resulting in compact systems. There are several kinds of conventional and non-conventional opening switch technologies available depending upon the time scale and energy of operation. Several new concepts have also been proposed and attempted in the field though may not have been fruitfully applied so far. A brief description of all such schemes is provided in this paper. Some details are also given on electrically exploding metal switch technique which has been developed in our laboratory in last few years. (author)

  20. [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.

  1. 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....

  2. 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.

  3. Programmable Power Supply for AC Switching Magnet of Proton Accelerator

    CERN Document Server

    Jeong, Seong-Hun; Kang Heung Sik; Lee, Chi-Hwan; Lee, Hong-Gi; Park, Ki-Hyeon; Ryu, Chun-Kil; Sik Han, Hong; Suck Suh, Hyung

    2005-01-01

    The 100-MeV PEFP proton linac has two proton beam extraction lines for user' experiment. Each extraction line has 5 beamlines and has 5 Hz operating frequency. An AC switching magnet is used to distribute the proton beam to the 5 beamlines, An AC switching magnet is powered by PWM-controlled bipolar switching-mode converters. This converter is designed to operate at ±350A, 5 Hz programmable step output. The power supply is employed IGBT module and has controlled by a DSP (Digital Signal Process). This paper describes the design and test results of the power supply.

  4. 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.

  5. Laboratory Switching Power Supply

    OpenAIRE

    Slezák, Jakub

    2009-01-01

    This bachelor’s thesis is concerned with design switching power supply based on forward converter with output voltage regulated in the range of 3 to 30V and load current to 1 A. First of all, it discusses the theoretical solution of basic types of converters and switching power supply problems. Followed by a proposal of various parts source, which was first established in the test version on the test board. Then was proposed printed circuit board and complete mechanical solutions. Source is a...

  6. Photonics in Switching

    OpenAIRE

    Hinton, Harvard S.

    1992-01-01

    One of the keys to the future of telecommunications companies will be their ability to provide new broadband services to both the business community and residential customers. With the new services will come the need for the equivalent of a broadband switching office. Such a system could require the capability of supporting in excess of 10000 users with broadband channel bit rates exceeding 100 Mb/s. This implies a switching fabric the aggregate bit rate of which could be greater than 1 Tb/s....

  7. Superselective intra-arterial infusion via the superficial temporal artery and occipital artery for gingival carcinoma of the mandible. Simultaneous catheter placement to the maxillary artery and facial artery

    International Nuclear Information System (INIS)

    Superselective intra-arterial infusion via the superficial temporal artery (STA) has become useful for oral cancer. Approaching via the occipital artery (OA) enables superselective intra-arterial infusion when catheter placement via the STA is impossible. Therefore, simultaneous catheter placement via the STA and OA is possible. We report a surgical method of simultaneous catheter placement via the STA and OA to achieve retrograde superselective intra-arterial infusion for gingival carcinoma of the mandible. Preoperatively, three-dimensional computed tomography angiography was performed to identify the route of the external carotid artery and branches such as the STA, OA, maxillary artery, and facial artery (FA). Thirteen patients with mandibular gingival cancer underwent catheter placement via the STA and OA under local anesthesia. Catheter placement via the STA and OA was superselectively successful in all the patients. The mean operating time was 150.8 min. Catheter placed to the FA via the OA was dislocated during the treatment in one patient, and so the catheter was replaced. This method is useful to enable superselective intra-arterial chemotherapy to the whole gingival carcinoma of the mandible from the start of treatment compared with approaching via the STA. (author)

  8. 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.

  9. 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.

  10. Investigation of a High-Power, High-Pressure Spark Gap Switch with High Repetition Rate

    OpenAIRE

    Rahaman, Hasibur

    2007-01-01

    Micro plasmas in a pressurized spark gap switch were under investigation in the present dissertation. In contrast to the requirements of commonly used high power switches, this work was focused on investigations of a high repetition rate and simultaneously maintaining a fast switching time at a low energy transfer per pulse. The spark gap was operating in a free running mode, without any triggering. The breakdown was only initiated by overvoltage. For this particular switch, a theoretical cha...

  11. Dynamic contrast-enhanced ultrasound and transient arterial occlusion for quantification of arterial perfusion reserve in peripheral arterial disease

    International Nuclear Information System (INIS)

    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 (tmax), slope to maximum (m), vascular response after occlusion (AUCpost), 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 max was delayed (31.2 ± 13.6 vs. 16.7 ± 8.5 s, p 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.

  12. 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.

  13. 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....

  14. 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.

  15. 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.

  16. Optical packet switched networks

    DEFF Research Database (Denmark)

    Hansen, Peter Bukhave

    1999-01-01

    in interferometric wavelength converters is investigated showing that a 10 Gbit/s 19 4x4 swich blocks can be cascaded at a BER of 10-14. An analytical traffic model enables the calculation of the traffice performance of a WDM packet network. Hereby the importance of WDM and wavelegth conversion in the switch blocks...... is investigated showing more constant gain characteristics and an increased saturation input power from -17 to -4 dBm. Dynamically, the GC-SOA is demonstrated to perform better at bit rates over 10 Gbit/s for RZ than NRZ signals. Additionally, a 4x4 passive InP mach-Zehnder interferometric space switch has been...... power dynamic range (IPDR). Moreover, the IPDR of the IWC alone is only -3.5 dB at 10 Gbit/s, however, control schemes are introduced yielding an IPDR of both -28 dB and -40 dB. Finally, the feasibility of an all-optical WDM packet switch block is demonstrated at 20 Gbit/s for a 4x4 switch block with 4...

  17. 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...

  18. Switched Multistage Vector Quantizer

    Directory of Open Access Journals (Sweden)

    M Satya Sai Ram

    2010-01-01

    Full Text Available This paper investigates the use of a new hybrid vector quantizer called Switched Multi stage vector quantization (SWMSVQ technique using hard and soft decision schemes, for coding of narrow band speech signals. This technique is a hybrid of Switch vector quantization technique and Multi stage vector quantization technique. SWMSVQ quantizes the linear predictive coefficients (LPC in terms of the line spectral frequencies (LSF. The spectral distortion performance, computational complexity and memory requirements of SWMSVQ using hard and soft decision schemes are compared with Split vector quantization (SVQ technique, Multi stage vector quantization (MSVQ technique, Switched Split vector quantization (SSVQ technique using hard decision scheme, and Multi Switched Split Vector quantization (MSSVQ technique using hard decision scheme. From results it is proved that SWMSVQ using soft decision scheme is having less spectral distortion, computational complexity and memory requirements when compared to SVQ, MSVQ, SSVQ and SWMSVQ using hard decision scheme, but high when compared to MSSVQ using hard decision scheme. So from results it is proved that SWMSVQ using soft decision scheme is better when compared to SVQ, MSVQ, SSVQ and SWMSVQ using hard decision schemes in terms of spectral distortion, computational complexity and memory requirements but is having greater spectral distortion, computational complexity and memory requirements when compared to MSSVQ using hard decision.

  19. 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.

  20. 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.

  1. 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

  2. Ultrafast gas switching experiments

    International Nuclear Information System (INIS)

    We describe recent experiments which studied the physics of ultrafast gas breakdown under the extreme overvoltages which occur when a high pressure gas switch is pulse charged to hundreds of kV in 1 ns or less. The highly overvolted peaking gaps produce powerful electromagnetic pulses with risetimes Khz at > 100 kV/m E field

  3. 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.

  4. 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.

  5. 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.

  6. Angioplasty and stent placement - peripheral arteries - discharge

    Science.gov (United States)

    Percutaneous transluminal angioplasty - peripheral artery - discharge; PTA - peripheral artery - discharge; Angioplasty - peripheral artery - discharge; Balloon angioplasty - peripheral artery- discharge; PAD - PTA ...

  7. Job Switching and Wage Growth

    OpenAIRE

    Faberman, R. Jason; Justiniano, Alejandro

    2015-01-01

    This article shows a remarkably strong relationship between job switching and nominal wage growth. We also find a fairly strong relationship between job switching and the cyclical component of inflation. Furthermore, job switching seems to be predictive of both wage growth and inflation.

  8. Language Switching and Language Competition

    Science.gov (United States)

    Macizo, Pedro; Bajo, Teresa; Paolieri, Daniela

    2012-01-01

    This study examined the asymmetrical language switching cost in a word reading task (Experiment 1) and in a categorization task (Experiment 2 and 3). In Experiment 1, Spanish-English bilinguals named words in first language (L1) and second language (L2) in a switching paradigm. They were slower to switch from their weaker L2 to their more dominant…

  9. 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.

  10. 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.

  11. Kinematic Simulation and Optimization for Torsion Spring of Pawl in Spring Operating Mechanism of High Voltage Switch Based on Adams Software%基于Adams的高压开关弹簧机构中掣子扭簧的仿真及优化

    Institute of Scientific and Technical Information of China (English)

    金松安; 王瑜; 骆虎

    2012-01-01

    针对高压开关设计中掣子扭簧的设计,建立了弹簧操作机构的运动学模型,在Solid edge中建立仿真模型;在Adams中建立虚拟样机并进行运动学仿真,对掣子扭簧参数进行优化,提出了一种对高压开关进行虚拟设计的有效方法.%This paper established a kinematic model of spring operating mechanism of high voltage switch in order to solve the problems in torsion spring of pawl.and created spring operating mechanism with Solid edge software. Based on virtual prototype technology,the kinematic behavior of spring operating mechanism was simulated with Adams software and the torsion spring of pawl was optimized.This research is expected to supply a new method for virtual design of high voltage switch.

  12. 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.

  13. 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.)

  14. [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.

  15. 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.

  16. Voltage-controllable wavelength-selective optical switching based on multiply cascaded long-period fiber gratings

    Science.gov (United States)

    Han, Young-Geun; Choi, Sun-Min; Kim, Sang Hyuck; Lee, Sang Bae

    2003-11-01

    A novel wavelength-selective optical switching device based on multiply cascaded long-period fiber gratings is proposed and experimentally demonstrated. The on and off states of each channel in the optical switching device can be effectively switched by voltage-controllable coil heaters. The device has advantages of multichannel operation, multiwavelength selectivity, and bandwidth controllability. It can be useful for applications in multiwavelength operational signal gating, optical switching devices, routers, and multiplexers in optical communication systems.

  17. Active RF Pulse Compression Using Electrically Controlled Semiconductor Switches

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J.; Tantawi, S.; /SLAC

    2007-03-21

    In this paper, we present the recent results of our research on the ultra-high power fast silicon RF switch and its application on active X-Band RF pulse compression systems. This switch is composed of a group of PIN diodes on a high purity silicon wafer and has achieved a switching time of 300ns. The wafer is inserted into a cylindrical waveguide operating in the TE01 mode. Switching is performed by injecting carriers into the bulk silicon through a high current pulse. The RF energy is stored in a room-temperature, high-Q 375 ns delay line; it is then extracted out of the line in a short time using the switch. The pulse compression system has achieved a gain of 8, which is the ratio between output and input power.

  18. Synchronization Between Two Different Switched Chaotic Systems By Switching Control

    Directory of Open Access Journals (Sweden)

    Du Li Ming

    2016-01-01

    Full Text Available This paper is concerned with the synchronization problem of two different switched chaotic systems, considering the general case that the master-slave switched chaotic systems have uncertainties. Two basic problems are considered: one is projective synchronization of switched chaotic systems under arbitrary switching; the other is projective synchronization of switched chaotic systems by design of switching when synchronization cannot achieved by using any subsystems alone. For the two problems, common Lyapunov function method and multiple Lyapunov function method are used respectively, an adaptive control scheme has been presented, some sufficient synchronization conditions are attainted, and the switching signal is designed. Finally, the numerical simulation is provide to show the effectiveness of our method.

  19. 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.

  20. [Popliteal artery entrapment syndrome].

    Science.gov (United States)

    Musumeci, S; Iuppa, A; Beneventano, G; Rinella, P; Mammano, M; Cinquegrani, E

    1986-12-15

    Trapped popliteal artery syndrome is relatively uncommon: the literature reports some 60 cases. The clinical picture is linked to compression of the popliteal artery by the gastrocnemius as it contracts, thus distorting the arterial route. The result is an interruption in the blood flow distally to the area involved due to stenosis of the blood vessel that is at first functional but becomes organic. PMID:3808379

  1. 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.

  2. Heritability of cilioretinal arteries

    DEFF Research Database (Denmark)

    Taarnhøj, Nina Charlotte; Munch, Inger C; Kyvik, Kirsten O;

    2005-01-01

    of healthy monozygotic and dizygotic twins were examined using digital fundus photography and visual assessment of grayscale fundus photographs and color transparencies to detect the presence of cilioretinal arteries. RESULTS: Cilioretinal arteries were present in 45.1% of participants and 28.8% of eyes....... The majority of cilioretinal arteries, 88.2%, were located temporally, and 11.8% were located nasally. Monozygotic twins had higher concordance rates for cilioretinal arteries than dizygotic twins. Tetrachoric correlations and Mantel-Haenszel odds ratios demonstrated statistically significant evidence...

  3. Peripheral artery disease - legs

    Science.gov (United States)

    ... if they have a history of: Abnormal cholesterol Diabetes Heart disease (coronary artery disease) High blood pressure ( hypertension ) Kidney disease involving hemodialysis Smoking Stroke ( cerebrovascular disease )

  4. 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。

  5. Proto-I switching and diode studies

    International Nuclear Information System (INIS)

    Proto-I is a 3 MV, 800 kA, 24 ns electron beam accelerator that is under development at Sandia Laboratories. It represents an initial effort to develop a scalable technology that is applicable to accelerators for electron beam driven, inertial confinement fusion studies. Energy is supplied to each of the two diodes from six oil-dielectric Blumlein transmission lines (PFL) operating in parallel. A Marx generator charges three intermediate storage, water-dielectric capacitors which subsequently transfer the stored energy to the PFL. The discharge of the PFL is initiated by the simultaneous closure of 12 triggered oil-dielectric rail switches. Data will be presented on the operation of these multichannel switches. The two diodes have a common anode. Cathode diameters can be varied from 10 to 60 cm. Results of initial diode experiments and comparisons with theory are discussed. Plasma filled diode experiments are also reported, indicating pinch collapse velocities in excess of 109 cm/s

  6. Proto-I switching and diode studies

    International Nuclear Information System (INIS)

    Proto-I is a 3 MV, 800 kA, 24 ns electron beam accelerator that is under development as an initial effort to develop a scalable technology that is applicable to accelerators for electron beam driven, inertial confinement fusion studies. Energy is supplied to each of the two diodes from six oil-dielectric Blumlein transmission lines (PFL) operating in parallel. A Marx generator charges three intermediate storage, water-dielectric capacitors which subsequently transfer the stored energy to the PFL. The discharge of the PFL is initiated by the simultaneous closure of 12 triggered oil-dielectric rail switches. Data are presented on the operation of these multichannel switches. The two diodes have a common anode. Cathode diameters can be varied from 10 to 60 cm. Results of initial diode experiments and comparisons with theory are discussed. Plasma filled diode experiments are also reported, indicating pinch collapse velocities in excess of 109 cm/s

  7. Right Coronary Artery Arising from Circumflex Artery: A Case of Single Coronary Artery Anomaly

    Directory of Open Access Journals (Sweden)

    Hekim Karapınar

    2013-08-01

    Full Text Available Coronary artery anomalies could be cause of conflicts for catheterization, especially, in the setting of acute coronary syndrome. We described a case of rare single coronary anomaly which the right coronary artery arisen from terminal part of left circumflex artery. Patient was presented with non-ST segment elevation myocardial infarction. Coronary angiography revealed subtotal stenosis of left anterior descending artery at the mid portion. Left circumflex artery lying in usual route and branch out the posterior descending artery. The right coronary artery arisen from terminal circumflex artery. Left anterior descending artery lesion was stented without any complication.

  8. The Smallest Molecular Switch

    OpenAIRE

    Emberly, Eldon G.; Kirczenow, George

    2003-01-01

    Ab-initio total energy calculations reveal benzene-dithiolate (BDT) molecules on a gold surface, contacted by a monoatomic gold STM tip to have two classes of low energy conformations with differing symmetries. Lateral motion of the tip or excitation of the molecule cause it to change from one conformation class to the other and to switch between a strongly and a weakly conducting state. Thus, surprisingly, despite their apparent simplicity these Au/BDT/Au nanowires are shown to be electrical...

  9. 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.

  10. Magnetic Cellular Switches

    OpenAIRE

    Overby, Darryl R.; Alenghat, Francis J.; Montoya-Zavala, Martín; Bei, HuCheng; Oh, Philmo; Karavitis, John; Ingber, Donald E.

    2004-01-01

    This paper focuses on the development of magnetic cellular switches to enable magnetic control of intracellular functions in living mammalian cells, including receptor signal transduction and gene transcription. Our approach takes advantage of the mechanosensitivity of adenosine 3′,5′-monophosphate (cAMP) induction and downstream transcription controlled by the cAMP regulatory element (CRE) to engineer gene constructs that optically report gene expression in living cells. We activate transcri...

  11. 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......, to your car and to your office, will also be explored during this workshop as a part of a connected lifestyle between different contexts....

  12. Immediate Bilateral Breast Reconstruction with Unilateral Deep Superior Epigastric Artery and Superficial Circumflex Iliac Artery Flaps.

    Science.gov (United States)

    Hansen, Keith S; Gutwein, Luke G; Hartman, Brett C; Sood, Rajiv; Socas, Juan

    2016-09-01

    Autologous breast reconstruction utilizing a perforator flap is an increasingly popular method for reducing donor site morbidity and implant-related complications. However, aberrant anatomy not readily visible on computed tomography angiography is a rare albeit real risk when undergoing perforator flap reconstruction. We present an operative case of a patient who successfully underwent a bilateral breast reconstruction sourced from a unilateral abdominal flap divided into deep superior epigastric artery and superficial circumflex iliac artery flap segments. PMID:27689054

  13. Cygnus Diverter Switch Analysis

    Energy Technology Data Exchange (ETDEWEB)

    G. Corrow, M. Hansen, D. Henderson, C. Mitton et al.

    2008-02-01

    The Cygnus Dual Beam Radiographic Facility consists of two 2.25-MV, 60-kA, 50-ns x-ray sources fielded in an underground laboratory at the Nevada Test Site. The tests performed in this laboratory involve study of the dynamic properties of plutonium and are called subcritical experiments. From end-to-end, the Cygnus machines utilize the following components: Marx generator, water-filled pulse-forming line (PFL), waterfilled coaxial transmission line (WTL), 3-cell inductive voltage adder (IVA), and rod-pinch diode. The upstream WTL interface to the PFL is via a radial insulator with coaxial geometry. The downstream WTL terminates in a manifold where the center conductor splits into three lines which individually connect to each of the IVA cell inputs. There is an impedance mismatch at this juncture. It is a concern that a reflected pulse due to anomalous behavior in the IVA or diode might initiate breakdown upon arrival at the upstream PFL/WTL insulator. Therefore near the beginning of the WTL a radial diverter switch is installed to protect the insulator from over voltage and breakdown. The diverter has adjustable gap spacing, and an in-line aqueous-solution (sodium thiosulfate) resistor array for energy dissipation. There are capacitive voltage probes at both ends of the WTL and on the diverter switch. These voltage signals will be analyzed to determine diverter performance. Using this analysis the usefulness of the diverter switch will be evaluated.

  14. Tunneling Nanoelectromechanical Switches Based on Compressible Molecular Thin Films.

    Science.gov (United States)

    Niroui, Farnaz; Wang, Annie I; Sletten, Ellen M; Song, Yi; Kong, Jing; Yablonovitch, Eli; Swager, Timothy M; Lang, Jeffrey H; Bulović, Vladimir

    2015-08-25

    Abrupt switching behavior and near-zero leakage current of nanoelectromechanical (NEM) switches are advantageous properties through which NEMs can outperform conventional semiconductor electrical switches. To date, however, typical NEMs structures require high actuation voltages and can prematurely fail through permanent adhesion (defined as stiction) of device components. To overcome these challenges, in the present work we propose a NEM switch, termed a "squitch," which is designed to electromechanically modulate the tunneling current through a nanometer-scale gap defined by an organic molecular film sandwiched between two electrodes. When voltage is applied across the electrodes, the generated electrostatic force compresses the sandwiched molecular layer, thereby reducing the tunneling gap and causing an exponential increase in the current through the device. The presence of the molecular layer avoids direct contact of the electrodes during the switching process. Furthermore, as the layer is compressed, the increasing surface adhesion forces are balanced by the elastic restoring force of the deformed molecules which can promote zero net stiction and recoverable switching. Through numerical analysis, we demonstrate the potential of optimizing squitch design to enable large on-off ratios beyond 6 orders of magnitude with operation in the sub-1 V regime and with nanoseconds switching times. Our preliminary experimental results based on metal-molecule-graphene devices suggest the feasibility of the proposed tunneling switching mechanism. With optimization of device design and material engineering, squitches can give rise to a broad range of low-power electronic applications. PMID:26244821

  15. Node design in optical packet switched networks

    OpenAIRE

    Nord, Martin; Dittmann, Lars

    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 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 ...

  16. Comparison of Memory Assignment Schemes for Switch Architectures with Shareable Parallel Memory Modules

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2010-01-01

    Full Text Available Switching Architectures deploying shareable parallel memory modules are quite versatile in their ability to scale to higher capacity while retaining the advantage of sharing its entire memory resource among all input and output ports. The two main classes of such architectures, namely, the Shared Multibuffer-(SMB- based switch and the Sliding-Window-(SW- based packet switch, both deploy parallel memory modules that are physically separate but logically connected. Inspite of their similarity in regards to using shareable parallel memory modules, they differ in switching control and scheduling of packets to parallel memory modules. SMB switch uses centralized control whereas the SW switch uses a decentralized control for switching operations. In this paper, we present a new memory assignment scheme for the Sliding-Window (SW switch for assigning packets to parallel memory modules that maximizes the parallel storage of packets to multiple memory modules. We compare the performance of a sliding-window switch deploying this new memory assignment scheme with that of an SMB switch architecture under conditions of identical traffic type and memory resources deployed. The simulation results show that the new memory assignment scheme for the sliding window switch maximizes parallel storage of packets input in a given switch cycle, and it does not require speed-up of memory modules. Furthermore, it provides a superior performance compared to that of the SMB switch under the constraints of fixed memory-bandwidth and memory resources.

  17. Two-output Class E Isolated dc-dc Converter at 5 MHz Switching Frequency

    OpenAIRE

    Pavlovic, Zoran; Oliver Ramírez, Jesús Angel; Alou Cervera, Pedro; García Suárez, Oscar; Prieto López, Roberto; Cobos Márquez, José Antonio

    2010-01-01

    This paper presents a two output class-E isolated dcdc converter that regulates the output voltages at fixed switching frequency. The converter is simulated at operating frequency of 5 MHz. The converter output power is 40 W and the output voltages are 15 V and 5 V. All the switches operate at zero voltage switching (ZVS) conditions for the full load range. The circuit configuration is simple with small passive components which reduce the size of the converter. The circuit also has ...

  18. 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.

  19. Artery Agenesis: Ipsilateral Common Carotid Artery Hypoplasia

    Directory of Open Access Journals (Sweden)

    Omer Kaya

    2014-01-01

    Full Text Available A 42-year-old female patient, who had been diagnosed with an occlusion of her left internal carotid artery (ICA following Doppler ultrasonographic (US and digitally-subtracted angiographic (DSA examinations performed in an outer healthcare center in order to eliminate the underlying cause of her complaint of amorosis fugax, later applied to our hospital with the same complaint. At Doppler US performed in our hospital’s radiology department, her right common carotid artery (CCA was normal, but her left CCA was hypoplastic. The right internal artery (ICA was validated as normal. At the left side, however, the ICA was apparent only as a stump and it did not demonstrate a continuity. The diagnosis of ICA agenesis was confirmed by the utilization of Doppler US, CT, and DSA imaging, and it was concluded also that ipsilateral CCA hypoplasia could be evaluated as an important clue to the diagnosis of ICA agenesis.

  20. Diagnosis of Intracranial Artery Dissection

    Science.gov (United States)

    KANOTO, Masafumi; HOSOYA, Takaaki

    2016-01-01

    Cerebral arterial dissection is defined as a hematoma in the wall of a cervical or an intracranial artery. Cerebral arterial dissection causes arterial stenosis, occlusion, and aneurysm, resulting in acute infarction and hemorrhage. Image analysis by such methods as conventional angiography, computed tomography, magnetic resonance imaging, and so on plays an important role in diagnosing cerebral arterial dissection. In this study, we explore the methods and findings involved in the diagnosis of cerebral arterial dissection. PMID:27180630

  1. 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.

  2. 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.

  3. 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.

  4. 220 kV GIS隔离开关操作暂态过电压的原因与预防措施%Causes and Preventive Measures of Very Fast Transient Overvoltage During Operation of 220 kV GIS Disconnecting Switch

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    During operation of 220 kV GIS disconnecting switch of a substation, the arc discharge phenomenon frequently occurs between the insulating flange of GIS metal casing and the ground wire. This phenomenon is caused by VFTO during operation of the disconnecting switch. The corresponding protective measures and suggestions are offered to ensure safety and reliability of the power system.%  某变电站220 kV GIS设备隔离开关操作时,频繁发生GIS金属套管对地绝缘的法兰与接地线间打火放电现象。对这一现象进行了深入分析,认为是由于隔离开关操作产生的VFTO过电压造成的,并提出了相应的防护措施和建议,以保证电力系统的安全可靠性。

  5. 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.

  6. 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.

  7. Nanophotonic quantum phase switch with a single atom

    OpenAIRE

    Tiecke, Tobias; Thompson, Jeffrey Douglas; de Leon, Nathalie Pulmones; Liu, L; Vuletić, V.; Lukin, Mikhail D.

    2014-01-01

    By analogy to transistors in classical electronic circuits, quantum optical switches are important elements of quantum circuits and quantum networks1, 2, 3. Operated at the fundamental limit where a single quantum of light or matter controls another field or material system4, such a switch may enable applications such as long-distance quantum communication5, distributed quantum information processing2 and metrology6, and the exploration of novel quantum states of matter7. Here, by strongly ...

  8. 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.

  9. Repetitive plasma opening switch for powerful high-voltage pulse generators

    International Nuclear Information System (INIS)

    Results are presented of experimental studies of plasma opening switches that serve to sharpen the pulses of inductive microsecond high-voltage pulse generators. It is demonstrated that repetitive plasma opening switches can be used to create super-powerful generators operating in a quasi-continuous regime. An erosion switching mechanism and the problem of magnetic insulation in repetitive switches are considered. Achieving super-high peak power in plasma switches makes it possible to develop new types of high-power generators of electron beams and X radiation. Possible implementations and the efficiency of these generators are discussed

  10. Remote fiber optic switch powered by light for robust interrogation of fiber Bragg grating sensor networks

    International Nuclear Information System (INIS)

    In this work, a remote fiber optic switch powered by light is demonstrated experimentally. This fiber optic switch is powered by a photovoltaic power converter illuminated by a Raman laser. The switch can operate at distances up to 100 km. This switch is used to develop a remote resilient fiber Bragg grating (FBG) multiplexing network interrogated by a commercial FBG interrogator. In the proposed set-up the switch selects the branch of the FBG network located 50 km away from the interrogation unit in order to enable a two-way interrogation path for each sensor to prevent connection failures or fiber breakages. (paper)

  11. 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.

  12. Hot-switched lifetime and damage characteristics of MEMS switch contacts

    International Nuclear Information System (INIS)

    Using a custom built contact testing system, direct current micro contact damage under hot-switching conditions was explored in ruthenium-on-ruthenium contacts operated at a contact force of approximately 400 µN. For the first time, contact damage on making and breaking contact under bias (leading and trailing edge hot switching) is compared. Trailing-edge hot switching leads to significantly higher adhesion (1.5–4 times higher) than leading-edge hot switching. The high-voltage tests (3.5 V) lead to polarity-dependent material transfer, with material moving in the direction of the electric field. The amount of material transfer does not depend strongly on the current limit from 0.78 to 380 mA. The low voltage (0.71 V) tests result in much less damage, and the material transfer does not have a clear directionality. However, the amount of damage does increase significantly as the current limit is increased from 16 to 78 mA. Also observed for the first time is a new type of high-current, short duration current spike associated with hot switching events at voltages above 1.5 V. The fact that these spikes occur at the higher voltage but not at the lower voltage suggests (but does not prove) that they are associated with the polarity dependent material transfer. (paper)

  13. Study of the Switching Errors in an RSFQ Switch by Using a Computerized Test Setup

    International Nuclear Information System (INIS)

    The problem of fluctuation-induced digital errors in a rapid single flux quantum (RSFQ) circuit has been a very important issue. In this work, we calculated the bit error rate of an RSFQ switch used in superconductive arithmetic logic unit (ALU). RSFQ switch should have a very low error rate in the optimal bias. Theoretical estimates of the RSFQ error rate are on the order of 10-50per bit operation. In this experiment, we prepared two identical circuits placed in parallel. Each circuit was composed of 10 Josephson transmission lines (JTLs) connected in series with an RSFQ switch placed in the middle of the 10 JTLs. We used a splitter to feed the same input signal to both circuits. The outputs of the two circuits were compared with an RSFQ exclusive OR (XOR) to measure the bit error rate of the RSFQ switch. By using a computerized bit-error-rate test setup, we measured the bit error rate of 2.18 x 10-12 when the bias to the RSFQ switch was 0.398 mA that was quite off from the optimum bias of 0.6 mA.

  14. 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

  15. Advances in integrated photonic circuits for packet-switched interconnection

    Science.gov (United States)

    Williams, Kevin A.; Stabile, Ripalta

    2014-03-01

    Sustained increases in capacity and connectivity are needed to overcome congestion in a range of broadband communication network nodes. Packet routing and switching in the electronic domain are leading to unsustainable energy- and bandwidth-densities, motivating research into hybrid solutions: optical switching engines are introduced for massive-bandwidth data transport while the electronic domain is clocked at more modest GHz rates to manage routing. Commercially-deployed optical switching engines using MEMS technologies are unwieldy and too slow to reconfigure for future packet-based networking. Optoelectronic packet-compliant switch technologies have been demonstrated as laboratory prototypes, but they have so far mostly used discretely pigtailed components, which are impractical for control plane development and product assembly. Integrated photonics has long held the promise of reduced hardware complexity and may be the critical step towards packet-compliant optical switching engines. Recently a number of laboratories world-wide have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip. Our own work has focused on multi-input to multi-output switching matrices. Recently we have demonstrated 8×8×8λ space and wavelength selective switches using gated cyclic routers and 16×16 broadband switching chips using monolithic multi-stage networks. We now operate these advanced circuits with custom control planes implemented with FPGAs to explore real time packet routing in multi-wavelength, multi-port test-beds. We review our contributions in the context of state of the art photonic integrated circuit technology and packet optical switching hardware demonstrations.

  16. Circuit model of Rimfire switch

    International Nuclear Information System (INIS)

    A cascade gaps circuit model for Rimfire switch has been developed. The circuit model includes all stray capacitances and spark channel on-state conduction characteristics. It can not only describe the behavior of Rimfire switch, but also allow analysis of the time varying voltage and current at each part of the switch, describing the internal characters of the switch. PSpice was used to implement the cascade gaps circuit model and simulate a 700 kV Rimfire switch. The simulation shows that, the voltage of the whole switch will be higher than 700 kV when the laser triggered section has broken down but all cascade gaps keep dielectric, and the voltage of all gaps attenuates with high frequency oscillation. (authors)

  17. The economics of lamp switching

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-09-01

    The effect of switching off fluorescent lamps, in terms of electricity cost, was discussed. Fluorescent lamps are designed to burn for thousands of hours. Initially, it was believed that turning them off was not economical. However, with new fluorescent lamps available today, this no longer holds true. It was shown that as energy costs increase, it is advantageous to switch lamps off in office buildings during lunch, coffee breaks and other non-essential periods. Also, as labour and lamp costs increase it becomes even more economical to turn lamps on only when needed in some areas such as washrooms, stockrooms, etc. Inexpensive photo-electric and time-switch controls are readily available for automatic switching to eliminate the `human error` of forgetting to turn light off when they are not required. Over time, the energy saved would offset the cost of the switch controllers and the reduction in lamp life caused by repeated switching. 4 tabs., 2 figs.

  18. 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.

  19. TECAB - Totally Endoscopic Coronary Artery Bypass

    Medline Plus

    Full Text Available ... completely endoscopic coronary artery bypass grafting procedure using robotics. We call this operation a “TECAB,” “Totally Endoscopic ... scrub nurse, also a lot of experience with robotics now. And Dr. Atiq Rahman, fellow here for ...

  20. 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.

  1. Iatrogenic and noniatrogenic arterial trauma: a comparative study.

    Science.gov (United States)

    Lazarides, M K; Arvanitis, D P; Liatas, A C; Dayantas, J N

    1991-01-01

    During a 6-year period 22 patients were operated on because of iatrogenic arterial trauma (group A) and 43 sustained noniatrogenic arterial injury (group B). The group A injuries were caused by various arterial catheterization procedures for angiography or cardiac investigation (55%) or surgical interventions (45%). Haemorrhage was more common in group B than in group A (p less than 0.001). The mortality rate did not differ significantly between the groups (14% vs. 9%). Permanent disability was more common in group B (p less than 0.05), due mainly to higher incidence of associated venous, neural, skeletal or visceral injuries. Bypass operations tended to be more often performed in group B than in group A, but the difference was not statistically significant. Retrospective assessment of the appropriateness of technique, made separately by two vascular surgeons, revealed instances of potentially avoidable iatrogenic arterial injury. The rising incidence of iatrogenic arterial trauma may therefore be considered 'reducible'. PMID:1675876

  2. Comparação da perviedade entre artéria radial e veia safena em pacientes em pós-operatório de cirurgia de revascularização miocárdica com retorno dos sintomas Comparison of patency between radial artery and saphenous vein in a coronary artery bypass grafting post operative with return of the symptoms

    Directory of Open Access Journals (Sweden)

    Herbert Coelho Hortmann

    2010-06-01

    Full Text Available OBJETIVO: Comparar a perviedade da artéria radial e veia safena em pacientes com retorno dos sintomas após cirurgia de revascularização do miocárdio (CRVM. MÉTODOS: Estudo retrospectivo. No período de janeiro de 1998 a dezembro de 2005, foram realizadas 469 CRVMs com o uso da artéria radial dentre os enxertos, no Hospital Vera Cruz, em Belo Horizonte/MG. Destes, 94 pacientes apresentaram alterações isquêmicas no pós-operatório recente ou tardio e foram reestudados com cineangiocoronariografia. Os enxertos foram divididos em três grupos: artéria torácica interna (ATI, artéria radial (AR e veia safena (VS, e foram estratificados segundo a gravidade das lesões: sem lesão grave (OBJECTIVE: To compare the radial artery and saphenous vein's patency in patients with recurrence of symptoms in a coronary artery bypass grafting (CABG. METHODS: Retrospective study. From January 1998 to December 2005, 469 CABGs were performed using the radial artery as a graft, in Vera Cruz Hospital in Belo Horizonte/ MG. Among the patients who underwent those surgeries, 94 presented ischemic changes in early or late postoperative period, which led them to be re-evaluated by coronary angiography. The grafts were divided in three groups: internal thoracic artery (ITA, radial artery (RA and saphenous vein (SV, and they were stratified according to the severity of injury: uninjured or patent (< 70%, severe obstruction (70 to 99% and occlusion. RESULTS: For the 94 patients in the study, 86 grafts of ITA, 94 of RA and 111 of SV were used. For the 86 ITA grafts, 73 (84.88% were found patent. For the 94 RA grafts, 55 (58.51% were found patent, and for the 111 SV grafts, 73 (65.76% were uninjured. A statistically significant difference (P= 0.001 was found between RA and SV grafts, with a higher patency found for VS graft. For the RA grafts, women presented a worse result concerning the RA patency (65.7% and 40.7%, with P = 0.006. Concerning coronary

  3. Noise-induced coherent switch

    Institute of Scientific and Technical Information of China (English)

    YUAN ZhanJiang; ZHANG Jiadun; ZHOU TianShou

    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.

  4. 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.

  5. Software Switching for Data Acquisition

    CERN Document Server

    CERN. Geneva; , 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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...

  12. An improved soft switched PWM interleaved boost AC-DC converter

    International Nuclear Information System (INIS)

    In this paper, an improved soft switched two cell interleaved boost AC/DC converter with high power factor is proposed and investigated. A new auxiliary circuit is designed and added to two cell interleaved boost converter to reduce the switching losses. The proposed auxiliary circuit is implemented using only one auxiliary switch and a minimum number of passive components without an important increase in the cost and complexity of the converter. The main advantage of this auxiliary circuit is that it not only provides zero-voltage-transition (ZVT) for the main switches but also provides soft switching for the auxiliary switch and diodes. Though all semiconductor devices operate under soft switching, they do not have any additional voltage and current stresses. The proposed converter operates successfully in soft switching operation mode for a wide range of input voltage level and the load. In addition, it has advantages such as fewer structure complications, lower cost and ease of control. In the study, the transition modes for describing the behavior of the proposed converter in one switching period are described. A prototype with 600 W output power, 50 kHz/cell switching frequency, input line voltage of 110-220 Vrms and an output voltage of 400 Vdc has been implemented. Analysis, design and the control circuitry are also presented in the paper.

  13. 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.

  14. 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.

  15. 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.

  16. False iliac artery aneurysm following renal transplantation

    DEFF Research Database (Denmark)

    Levi, N; Sønksen, Jens Otto Reimers; Schroeder, T V;

    1999-01-01

    We report a very rare case of a false iliac artery aneurysm following renal transplantation. The patient was a 51-year-old women who presented with a painful 10 x 10 cm pulsating mass in her left iliac fossa. The patient had received a second cadaveric renal transplantation 5 years previously....... The graft never functioned and transplant nephrectomy was performed 2 weeks later. A CT-scanning showed a 10 x 10 cm large aneurysm arising from the left external iliac artery. At operation a large false aneurysm was identified arising from the original transplant anastomotic site. Due to the extent...

  17. LCT protective dump-switch tests

    International Nuclear Information System (INIS)

    Each of the six coils in the Large Coil Task (LCT) has a separate power supply, dump resistor, and switching circuit. Each switching circuit contains five switches, two of which are redundant. The three remaining switches perform separate duties in an emergency dump situation. These three switches were tested to determine their ability to meet the LCT conditions

  18. 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.

  19. 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.

  20. 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.

  1. Coronary artery spasm

    Science.gov (United States)

    ... blocker or a long-acting nitrate long-term. Beta-blockers are another type of medicine that is used with other coronary artery problems. However, beta-blockers may make this problem worse. They should be ...

  2. Peripheral Arterial Disease

    Science.gov (United States)

    Peripheral arterial disease (PAD) happens when there is a narrowing of the blood vessels outside of your heart. The cause of ... smoking. Other risk factors include older age and diseases like diabetes, high blood cholesterol, high blood pressure, ...

  3. 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 ...

  4. 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 ...

  5. Coronary Artery Bypass Surgery

    Science.gov (United States)

    ... don't help, you may need coronary artery bypass surgery. The surgery creates a new path for ... narrowed area or blockage. This allows blood to bypass (get around) the blockage. Sometimes people need more ...

  6. 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

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

    Science.gov (United States)

    Norregaard, Kamilla; Andersson, Magnus; Sneppen, Kim; Nielsen, Peter Eigil; Brown, Stanley; Oddershede, Lene B

    2013-10-22

    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 regulation is understood. Using single molecule analysis, we directly examined the stability of the CI-operator structure in its natural, supercoiled state. We marked positions adjacent to the λ operators with peptide nucleic acids and monitored their movement by tethered particle tracking. Compared with relaxed DNA, the presence of supercoils greatly enhances juxtaposition probability. Also, the efficiency and cooperativity of the λ switch is significantly increased in the supercoiled system compared with a linear assay, increasing the Hill coefficient. PMID:24101469

  8. Convertible resistive switching characteristics between memory switching and threshold switching in a single ferritin-based memristor.

    Science.gov (United States)

    Zhang, Chaochao; Shang, Jie; Xue, Wuhong; Tan, Hongwei; Pan, Liang; Yang, Xi; Guo, Shanshan; Hao, Jian; Liu, Gang; Li, Run-Wei

    2016-04-01

    A bio-memristor fabricated with ferritin exhibits novel resistive switching characteristics wherein memory switching and threshold switching are made steadily coexistent and inter-convertible through controlling the magnitude of compliance current presets. PMID:26967024

  9. 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.

  10. 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.

  11. 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

  12. Low-voltage broadband hybrid plasmonic-vanadium dioxide switches

    CERN Document Server

    Joushaghani, Arash; Paradis, Suzanne; Alain, David; Aitchison, J Stewart; Poon, Joyce K S

    2012-01-01

    Surface plasmon polaritons can substantially reduce the sizes of optical devices, since they can concentrate light to (sub)wavelength scales. However, (sub)wavelength-scale electro-optic plasmonic switches or modulators with high efficiency, low insertion loss, and high extinction ratios remain a challenge due to their small active volumes. Here, we use the insulator-metal phase transition of a correlated-electron material, vanadium dioxide, to overcome this limitation and demonstrate compact, broadband, and efficient plasmonic switches with integrated electrical control. The devices are micron-scale in length and operate near a wavelength of 1550 nm. The switching bandwidths exceed 100 nm and applied voltages of only 400 mV are sufficient to attain extinction ratios in excess of 20 dB. Our results illustrate the potential of using phase transition materials for highly efficient and ultra-compact plasmonic switches and modulators.

  13. 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

  14. 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.

  15. 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

  16. Switching Costs in Accounting Services

    OpenAIRE

    Fatih Koç; Nisa Kıymet Şahin

    2015-01-01

    Switching cost is defined as possible costs that customers may encounter when they want to change the firm they buy service, and an important subject in terms of accounting services. Particularly, small business entrepreneurs’ not having knowledge about accounting procedures, and sharing private information with accounting firms make switching costs more important for accounting services. Thus, the aim of this study is...

  17. 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.

  18. 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.

  19. Involvement of IP3-receptor activation in endothelin-1-induced Ca(2+) influx in rat pulmonary small artery.

    Science.gov (United States)

    Kato, K; Okamura, K; Hatta, M; Morita, H; Kajioka, S; Naito, S; Yamazaki, J

    2013-11-15

    We examined the endothelin-1 (ET-1)-induced increase in the intracellular free Ca(2+) concentration ([Ca(2+)]i) in fura-2-loaded rat pulmonary small arteries. ET-1 (30 nM) elicited a long-lasting increase in [Ca(2+)]i in physiological salt solution (PSS). In subsequent experiments, arteries were pretreated with BQ-788, an ETB-specific blocker, to allow us to focus on responses mediated via the ETA receptor, the existence of which was confirmed by immunohistochemistry. In Ca(2+)-free PSS, ET-1 evoked a small transient increase in [Ca(2+)]i, indicating Ca(2+) release from the SR (sarcoplasmic reticulum). After a switch to PSS (containing 2mM CaCl2), ET-1 elicited a long-lasting increase in [Ca(2+)]i that was not inhibited by 1 μM nicardipine, an L-type Ca(2+)-channel inhibitor, suggesting involvement of a Ca(2+)-influx pathway independent of that channel. In arteries preincubated with 30 μM cyclopiazonic acid (CPA) or 2 μM thapsigargin (TG), the ET-1-induced Ca(2+)-release was greatly reduced, and the induced Ca(2+)-influx was attenuated. U-73122, a phospholipase C (PLC) inhibitor, had inhibitory effects similar to those of CPA and TG on the ET-1-induced Ca(2+)-release and Ca(2+)-influx, whereas U-73343, an inactive analogue of U-73122, had no such effects. Two putative membrane-permeable IP3-receptor blockers, 2-aminoethoxydiphenyl borate (2APB, 50 μM) and Xestospongin C (20 μM), (a) almost completely inhibited the ET-1-induced Ca(2+)-release and Ca(2+)-influx, and (b) reduced the ET-1-induced contraction. These results indicate that in rat pulmonary small arteries, ET-1 induces receptor-operated Ca(2+) influx via the ETA receptor, and that this influx interacts with InsP3-receptor activation. PMID:24157978

  20. Experiments in magnetic switching

    International Nuclear Information System (INIS)

    Magnetic switching offers an alternative to overcoming the rep-rate and life limitations of the spark gaps in the ETA/ATA induction accelerators. The principle has been applied for many years to radar modulators but at much lower power levels and longer pulse lengths. Comparatively recent developments in magnetic materials together with some optimal circuits have made it possible to go well beyond the state of the art. A magnetic modulator has been built which steps up and compresses a 25 kV, 5 μs pulse into a 250 kV, 50 ns pulse. A second magnetic modulator has been built and installed to replace four Blumleins and spark gaps in order to provide triggers for the complete ETA injector and accelerator. The paper outlines some practical and theoretical considerations affecting the design of the magnetic pulse generator

  1. Optimized scalable network switch

    Energy Technology Data Exchange (ETDEWEB)

    Blumrich, Matthias A. (Ridgefield, CT); Chen, Dong (Croton on Hudson, NY); Coteus, Paul W. (Yorktown Heights, NY)

    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.

  2. 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.

  3. 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.

  4. 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

  5. Heterogeneity of coronary arterial branching geometry

    Science.gov (United States)

    Wan, Shu-Yen; Reyes, Denise A.; Higgins, William E.; Ritman, Erik L.

    2000-04-01

    Past measurements of arterial branching geometry have indicated that the branching geometry is somewhat consistent with an optimal trade-off between the work needed to build and maintain the arterial tree and the work needed to operate the tree as a transport system. The branching geometry is also consistent with the mechanism that acutely adjusts the lumen diameter by way of maintaining a constant shear stress by dilating (or constricting) the arteries via the nitric oxide mechanism. However, those observations also indicate that there is considerable variation about the predicted optimization, both within any one individual and between individuals. Possible causes for this variation include: (1) measurement noise -- both due to the imprecision of the method but also the preparation of the specimen for applying the measurement technique, (2) the fact that the measurement task presents a major logistic problem, which increases as the vessel size decreases (but the number of branches correspondingly doubles at each branching) and results in progressive under-sampling as the vessel size decreases, (3) because of the logistic task involved the number of arterial trees analyzed is also greatly limited, and (4) there may indeed be actual heterogeneity in the geometry which is due to slight variation in implementation of the 'rules' used to construct a vascular tree. Indeed, it is this latter possibility that is of considerable physiological interest as it could result in the observed heterogeneity of organ perfusion and also provide some insight into the relative importance of 'initial ' conditions (i.e., how the vascular tree initially develops during embryogenesis) and the adaptive mechanisms operative in the maturing individual. The use of micro-CT imaging to provide 3D images of the intact vascular tree within the intact organ overcomes or minimizes the logistic problems listed above. It is the purpose of this study to examine whether variability in the branching

  6. Mechanical properties of porcine intralobar pulmonary arteries.

    Science.gov (United States)

    Ohtaka, H; Hogg, J C; Moreno, R H; Paré, P D; Schellenberg, R R

    1988-04-01

    The isobaric and isovolumetric properties of intrapulmonary arteries were evaluated by placing a highly compliant balloon inside arterial segments. The passive pressure-volume (P-V) curve was obtained by changing volume (0.004 ml/s) and measuring pressure. The isobaric active volume change (delta V) or isovolumetric active pressure change (delta P) generated by submaximal histamine was measured at four different transmural pressures (Ptm's) reached by balloon inflation. The maximal delta P = 11.2 +/- 0.6 cmH2O (mean +/- SE) was achieved at 30.8 +/- 1.2 cmH2O Ptm and maximal delta V = 0.20 +/- 0.02 ml at 16.7 +/- 1.7 cmH2O Ptm. The P-V relationships were similar when volume was increased after either isobaric or isovolumetric contraction. The calculated length-tension (L-T) relationship showed that the active tension curve was relatively flat and that the passive tension at the optimal length was 149 +/- 11% of maximal active tension. These data show that 1) a large elastic component operates in parallel with the smooth muscle in intralobar pulmonary arteries, and 2) the change in resistance associated with vascular expansion of the proximal arteries is independent of the type of contraction that occurs in the more distal arterial segments. PMID:3378988

  7. Channelized coplanar waveguide pin-diode switches

    Science.gov (United States)

    Ponchak, G. E.; Simons, R. N.

    1989-01-01

    Three different types of p-i-n diode, reflective CPW switches are presented. The first two switches are the series and the shunt mounted diode switches. Each has achieved greater than 15 dB of isolation over a broad bandwidth. The third switch is a narrow band, high isolation switched filter which has achieved 19 dB of isolation. Equivalent circuits and measured performance for each switch is presented.

  8. A Research Agenda for Evaluating Strength of Internal Preferences and External Influences in Consumer Smartphone Switching

    OpenAIRE

    Nykänen, Jussi Ilmari; Tuunainen, Virpi Kristiina; Tuunanen, Tuure

    2015-01-01

    This article proposes a research agenda to study what causes consumers to switch smartphone manufacturer and operating system brands. International consumer survey is planned for data collection and structural equation modeling method will be used to extrapolate whether internal preferences play a larger role than external influences in consumers’ switching behavior. The effects are expected to be moderated by behavioral control, subjective uncertainty and prior switching ex...

  9. Active Clamped ZVS Forward Converter With Soft-Switched Synchronous Rectifier

    OpenAIRE

    AÇIK, Adnan; ÇADIRCI, Işık

    2002-01-01

    This paper presents the analysis, design and implementation of an active-clamped, ZVS forward converter equipped with a soft-switched synchronous rectifier (ACFC-SR) proposed for high-efficiency, low output voltage dc-dc converter applications. The converter efficiency is maximized due to the soft-switching of the main, active clamp, synchronous rectifier and freewheeling MOSFET switches. The operating principles of the ACFC-SR are analyzed in detail and the converter performance is ...

  10. Micro-arcing and arc erosion minimization using a DC hybrid switching device

    OpenAIRE

    Swingler, J.; McBride, J. W.

    2008-01-01

    Hybrid switching devices utilize the advantages of both conventional electrical contacts and solid state electronics to minimize arcing during opening and closing operations. This can result in higher reliability and reduces the need for high cost specialist contact materials. The hybrid switch does not eliminate arcing completely, due to the inductive nature of circuits; micro-arcing is known to occur. An experimental dc hybrid switching device is introduced which minimizes arcing for 42 ...

  11. Congenital coronary-pulmonary artery fistula originating from right and left coronary artery

    Directory of Open Access Journals (Sweden)

    Ali Kemal Gür

    2013-12-01

    Full Text Available Coronary artery fistula (CAF is a rare congenital anomalywith an incidence of 1 in 50 000 live births. The fistula wasobserved at the right coronary artery in 53%, the left coronaryartery in 42% and both coronary artery in 5% of thecases. Echocardiography examination in a 46 year-oldwoman with the symptoms of chest pain, palpitation anddyspnea revealed a severe mitral valve insufficiency anda moderate to severe tricuspid valve insufficiency. A CAForiginating from the proximal part of the left anterior descendingartery (LAD and another fistula originating fromosteal part of the right coronary artery (RCA were detectedby coronary angiography. Both fistulas were draininginto the main pulmonary artery. The coronary artery fistulaclosed under cardiopulmonary by-pass. Mitral insufficiencyoriginated from the posterior leaflet was diagnosedintra-operative exploration, and thereafter it was repairedwith mitral annuloplasty including a quadrangular resectionand use of a 32 No St Jude mitral ring. Tricuspid valvewas repaired with Calangos Ring annuloplasty. Followingsix day hospital stay, the woman was discharged free ofany symptom.Key words: Dyspnea, double arteriovenous fistula, mitral and tricuspid insufficiency

  12. Catheter placement via the occipital artery to achieve superselective intra-arterial chemotherapy for oral cancer

    International Nuclear Information System (INIS)

    Superselective intra-arterial chemotherapy via the superficial temporal artery (STA) has become useful for oral cancer. However, this method can not be performed if catheter placement via the STA is impossible. Therefore, we report a surgical method for catheter placement via the occipital artery (OA) to achieve retrograde superselective intra-arterial chemotherapy. Preoperatively, three-dimensional computed tomography angiography was performed to identify the course of the external carotid artery and the relationship between OA and the target artery. Ten patients with oral cancer underwent catheter placement via the OA with Doppler ultrasound and Harmonic Scalpel under local anesthesia. Catheter placement via the OA was superselectively successful in all the patients. The mean exposure time of OA and mean operating time were 17.5 min and 70.5 min, respectively. Catheter placement via the OA is useful when catheter placement via the STA is impossible. Three-dimensional vascular mapping and the use of Doppler ultrasound and Harmonic Scalpel can shorten the surgical time. (author)

  13. 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 ...

  14. Devices for wavelength switching in optical networks

    Energy Technology Data Exchange (ETDEWEB)

    d`Alessandro, A.; Baran, J.E. [Bellcore, Red Bank, NJ (United States); Smith, D.A. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Electrical Engineering and Applied Physics

    1994-12-31

    Wavelength routing crossconnects are considered the core of WDM optical networks. They consist of optical switches independently rearrangeable for each wavelength channel and for any input-output configuration so that any path can be chosen almost arbitrarily by the network users. In general the implementation of the wavelength routing function requires complex switch arrays. Very simple wavelength-selection crossconnects can be realized by using acousto-optic switches (AOS), because of their unique ability of processing several optical signals simultaneously and their low driving power consumption, less than 10 mW/channel. AOS`s can be considered a particular evolution of acousto-optical tunable filters, whose integrated optic version on lithium niobate has been developed in several research institutions around the world in the past decade. This paper reviews the last accomplishments of AOS`s, whose specifications are directly tied with optical network requirements, the foremost challenge being a strong suppression of crosstalk. Dilated AOS`s can reduce interport crosstalk to below {minus}30 dB and apodization of acousto-optic interaction can reduce interchannel crosstalk to below {minus}15 dB during multiwavelength operation.

  15. 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.

  16. 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).

  17. 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.

  18. BILATERAL DUPLICATION OF RENAL ARTERIES

    Directory of Open Access Journals (Sweden)

    Prajkta A Thete

    2014-09-01

    Full Text Available Routine dissection of a male cadaver revealed the presence of bilateral double renal arteries. On the right side the accessory renal artery originated from the abdominal aorta just above the main renal artery. On the left side the accessory renal artery originated from the abdominal aorta about 1 cm above the main renal artery. Knowledge of the variations of renal vascular anatomy has importance in exploration and treatment of renal trauma, renal transplantation, renal artery embolization, surgery for abdominal aortic aneurysm and conservative or radical renal surgery

  19. 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.

  20. A Novel Soft-Switching Synchronous Buck Converter for Portable Applications

    OpenAIRE

    Mohapatra, K. K.; Swapnajit Pattnaik; Anup Kumar Panda

    2008-01-01

    This paper proposes a zero-voltage-transition (ZVT) pulse-width-modulated (PWM) synchronous buck converter, which is designed to operate at low voltage and high efficiency typically required for portable systems. A new passive auxiliary circuit that allows the main switch to operate with zero-voltage switching has been incorporated in the conventional PWM synchronous buck converter. The operation principles and a detailed steady-state analysis of the ZVT-PWM synchronous converter implemented ...

  1. Anomalous right coronary artery arising from left anterior descending artery

    Directory of Open Access Journals (Sweden)

    M.L. Sreenivas Kumar

    2012-07-01

    Full Text Available A 54-year-old male patient presented with acute myocardial infarction involving left anterior descending and right coronary artery territories. Coronary angiogram showed a single coronary artery with right coronary artery arising from left anterior descending artery (LAD, which coursed anterior to right ventricular outflow tract and thrombotic lesion in mid left anterior descending artery before origin of right coronary artery. The patient was treated with thrombolytic therapy and glycoprotein IIb/IIIa inhibitors. Anomalous origin of right coronary artery as a branch of LAD is a very rare type of congenital coronary artery anomalies. It is important to recognize this anomaly as it can be associated with extensive myocardial ischemia and sudden cardiac death in young persons even without atherosclerosis.

  2. Reusing the patent internal mammary artery as a conduit in redo coronary artery bypass surgery.

    Science.gov (United States)

    Nwaejike, Nnamdi; Tennyson, Charlene; Mosca, Roberto; Venkateswaran, Rajamiyer

    2016-03-01

    A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was, in patients with previous internal mammary artery/internal thoracic artery (ITA) grafts, can the internal mammary artery/ITA be reused/recycled in redo coronary artery bypass surgery? Fourteen papers were found using the reported search of which 10 represented the best evidence to answer the clinical question. There was variation in patient selection, the number of patients reported, outcome measures recorded, and methods and duration of follow-up. The results were mostly in favour of using a recycled ITA when it could be safely harvested. Most studies were retrospective. One large series of 60 patients who underwent redo coronary artery bypass grafting (CABG) using previously implanted ITAs had a mean time to reoperation of 117 ± 68 months. They reported no operative deaths; no patients required further or subsequent target vessel revascularization; 30-day mortality was 8.3% and myocardial infarction rate was 3%. Another two series of 16 and 12 patients underwent recycling of arterial grafts during coronary artery revascularization with no perioperative deaths in either. Postoperative angiography was performed in 10 patients in one of these studies, which showed excellent flow in all redone left internal thoracic artery (LITA) grafts. One study reported results from a prospective cohort of 9 patients who underwent redo coronary artery bypass grafting. Interval between operations was between 1 and 132 months. There was no perioperative mortality, but 1 patient required reintervention (to an interposition vein graft). A further study of 4 patients who underwent redo CABG using ITAs that were patent but with severe stenosis at the distal anastomosis had no mortality. Postoperative angiography showed patency of all grafts. There have also been 4 case reports on reusing the ITA/ITA in redo CABG with no damage to the reused LITA, no perioperative

  3. The magnetoelectrochemical switch.

    Science.gov (United States)

    Popa, Petru Lunca; Kemp, Neil T; Majjad, Hicham; Dalmas, Guillaume; Faramarzi, Vina; Andreas, Christian; Hertel, Riccardo; Doudin, Bernard

    2014-07-22

    In the field of spintronics, the archetype solid-state two-terminal device is the spin valve, where the resistance is controlled by the magnetization configuration. We show here how this concept of spin-dependent switch can be extended to magnetic electrodes in solution, by magnetic control of their chemical environment. Appropriate nanoscale design allows a huge enhancement of the magnetic force field experienced by paramagnetic molecular species in solutions, which changes between repulsive and attractive on changing the electrodes' magnetic orientations. Specifically, the field gradient force created within a sub-100-nm-sized nanogap separating two magnetic electrodes can be reversed by changing the orientation of the electrodes' magnetization relative to the current flowing between the electrodes. This can result in a breaking or making of an electric nanocontact, with a change of resistance by a factor of up to 10(3). The results reveal how an external field can impact chemical equilibrium in the vicinity of nanoscale magnetic circuits. PMID:25009179

  4. 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.

  5. 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

  6. Nanoelectromechanical digital logic circuits using curved cantilever switches with amorphous-carbon-coated contacts

    Science.gov (United States)

    Ayala, Christopher L.; Grogg, Daniel; Bazigos, Antonios; Bleiker, Simon J.; Fernandez-Bolaños, Montserrat; Niklaus, Frank; Hagleitner, Christoph

    2015-11-01

    Nanoelectromechanical (NEM) switches have the potential to complement or replace traditional CMOS transistors in the area of ultra-low-power digital electronics. This paper reports the demonstration of prototype circuits including the first 3-stage ring oscillator built using cell-level digital logic elements based on curved NEM switches. The ring oscillator core occupies an area of 30 μm × 10 μm using 6 NEM switches. Each NEM switch device has a footprint of 5 μm × 3 μm, an air gap of 60 μm and is coated with amorphous carbon (a-C) for reliable operation. The ring oscillator operates at a frequency of 6.7 MHz, and confirms the simulated inverter propagation delay of 25 ns. The successful fabrication and measurement of this demonstrator are key milestones on the way towards an optimized, scaled technology with sub-nanosecond switching times, lower operating voltages and VLSI implementation.

  7. 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

    2016-01-22

    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 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. PMID:26636189

  8. 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.

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

    DEFF Research Database (Denmark)

    Antal, Robert; Muntean, Nicolae; Boldea, Ion;

    2010-01-01

    This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology......, 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......) 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...

  10. 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.

  11. 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.

  12. 术前颈动脉评估与非体外循环冠状动脉旁路移植术后神经系统并发症的相关性%Association between carotid artery assessment before operation and neurological complications after OPCAB

    Institute of Scientific and Technical Information of China (English)

    许保磊; 毕齐; 宋哲; 李俊玉

    2015-01-01

    Objective To study the association between carotid artery assessment before operation and neurological complications (NC) after off‐pump coronary artery bypass (OPCAB) .Methods Five hundred and fifty‐six patients who underwent OPCAB from July 2010 to July 2012 in our hospital were included in this study .Their general condition ,past medical history ,head CT scan‐ning and carotid ultrasonography data were recorded before operation .Their nerve function was assessed before and 7 days after operation in order to judge whether NC ocurred .The patients were divided into NC group (n=118)and control group (n=438) .The association between carot‐id artery stenosis and risk factors for postoperative NC was analyzed .Results The total incidence of NC was 21 .2% .The incidence of ischemic stroke ,anoxic encephalopathy ,delirium ,postopera‐tive cognition impairment ,and anxiety/depression was 0 .7% ,2 .9% ,0 .7% ,10 .6% and 4 .9% re‐spectively .The incidence of ischemic stroke and carotid artery stenosis was significantly higher in NC group than in control group (P<0 .05) .Multivariate logistic regression analysis showed that the incidence of postoperative NC increased with the severity of carotid artery stenosis (OR=2.23 ,95% CI:1 .08 -4 .61 ,P= 0 .030) .Conclusion The incidence of NC following OPCAB in‐creases with the severity of carotid artery stenosis .%目的:探讨非体外循环下冠状动脉旁路移植术(OPCAB)后神经系统并发症(NC)的发病率及其危险因素,并观察颈动脉狭窄与术后NC的关系。方法收集2010年7月~2012年7月住北京安贞医院行OPCAB患者556例,术前完善患者一般情况及既往史,采集头部CT平扫及颈动脉超声结果;术前及术后7 d评估患者神经系统功能,判断术后是否发生NC ,分为NC组118例与非NC组438例;分析术后NC的危险因素,并探讨颈动脉狭窄与术后NC的相关性。结果术后 NC总发病率为21.2%,其中脑梗死0

  13. 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.

  14. Nucleotide kinase-based selection system for genetic switches.

    Science.gov (United States)

    Ike, Kohei; Umeno, Daisuke

    2014-01-01

    Ever-increasing repertories of RNA-based switching devices are enabling synthetic biologists to construct compact, self-standing, and easy-to-integrate regulatory circuits. However, it is rather rare that the existing RNA-based expression controllers happen to have the exact specification needed for particular applications from the beginning. Evolutionary design of is powerful strategy for quickly tuning functions/specification of genetic switches. Presented here are the steps required for rapid and efficient enrichment of genetic switches with desired specification using recently developed nucleoside kinase-based dual selection system. Here, the library of genetic switches, created by randomizing either the part or the entire sequence coding switching components, is subjected to OFF (negative) selection and ON (positive) selection in various conditions. The entire selection process is completed only by liquid handling, facilitating the parallel and continuous operations of multiple selection projects. This automation-liable platform for genetic selection of functional switches has potential applications for development of RNA-based biosensors, expression controllers, and their integrated forms (genetic circuits). PMID:24549617

  15. 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.

  16. 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.

  17. Polariton condensates: Electrical spin switching

    Science.gov (United States)

    Liew, T. C. H.

    2016-10-01

    Ultra-low-power electronic switching of stable exciton-polariton spin states has now been achieved in a semiconductor microcavity. This opens a new route to the integration of spin-based photonics and electronics.

  18. 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...... constrains its integration through standard deposition methods. Electroplating is a deposition technique which allows the deposition of thick films, and the integration of this technique to standard cleanroom fabrication is one of the focuses of this project, leading to large-scale fabrication of a new...

  19. Broadband hitless silicon electro-optic switch for on-chip optical networks.

    Science.gov (United States)

    Lira, Hugo L R; Manipatruni, Sasikanth; Lipson, Michal

    2009-12-01

    We report on the demonstration of a broadband (60 GHz), spectrally hitless, compact (20 microm x 40 microm), fast (7 ns) electro-optical switch. The device is composed of two coupled resonant cavities, each with an independently addressable PIN diode. This topology enables operation of the switch without perturbing adjacent channels in a wavelength division multiplexing (WDM) system. PMID:20052150

  20. A 1 Volt switched transconductor mixer in 0.18 μm CMOS

    NARCIS (Netherlands)

    Klumperink, Eric A.M.; Louwsma, Simon M.; Wienk, Gerard J.M.; Nauta, Bram

    2003-01-01

    A new CMOS mixer topology can operate at low supply voltages by using switches connected only to the supplies. Mixing is achieved exploiting two cross-coupled transconductors, which are alternatingly activated by the switches. A down conversion mixer prototype with 12 dB conversion gain was designed