In this paper,a passive muzzle arc control device(PMACD)of the augmented railguns is studied.By discussing its performance at different numbers of extra rails,a parameter optimization model is proposed.Through the cal...In this paper,a passive muzzle arc control device(PMACD)of the augmented railguns is studied.By discussing its performance at different numbers of extra rails,a parameter optimization model is proposed.Through the calculation model,it is found that the PMACD works well in the simple railgun,which refers to the gun that there is only one pair of rails in the inner bore.The PMACD may decrease the simple railgun’s armature peak current and muzzle arc,but affect its muzzle velocity not much.However,in the augmented railguns it has different characteristics.If the parameters of the PMACD are not selected suitable.It may increase the armature peak current and muzzle arc,but greatly decrease the velocity.The reason for this problem is that the extra rails generate a strong magnetic field in front of the armature,which induces a large current to change the armature current.It is also found that when the resistance and inductance parameters of the PMACD satisfy with the optimization formula,the PMACD can also play a good role in arc suppression in the augmented railguns.Experiments of an augmented railgun with a stainless steel PMACD are carried out to verify this optimization method.Results show that the muzzle arc is obviously controlled.This work may provide a reference for the design of the muzzle arc control device.展开更多
Periodic arrays of negative capacitance shunted piezoelectric patches are employed to control the band gaps of phononic beams. The location and the extent of induced band gap depend on the mismatch in impedance genera...Periodic arrays of negative capacitance shunted piezoelectric patches are employed to control the band gaps of phononic beams. The location and the extent of induced band gap depend on the mismatch in impedance generated by each patch. The total impedance mismatch is determined by the added mass and stiffness of each patch as well as the shunting electrical impedance. Therefore, the band gap of the shunted phononic beam can be actively tuned by appropriately selecting the value of negative capacitance. The control of the band gap of phononic beam with negative capacitive shunt is demonstrated numerically by employing transfer matrix method. The result reveals that using negative capacitive shunt to tune the band gap is effective.展开更多
Periodic arrays of hybrid-shunted piezoelectric patches are used to control the band-gaps of phononic metamaterial beams. Passive resistive-inductive （RL） shunting circuits can produce a narrow resonant band-gap （R...Periodic arrays of hybrid-shunted piezoelectric patches are used to control the band-gaps of phononic metamaterial beams. Passive resistive-inductive （RL） shunting circuits can produce a narrow resonant band-gap （RG）, and active negative capacitive （NC） shunting circuits can broaden the Bragg band-gaps （BGs）. In this article, active NC shunting circuits and passive resonant RL shunting circuits are connected to the same piezoelectric patches in parallel, which are usually called hybrid shunting circuits, to control the location and the extent of the band-gaps. A super-wide coupled band-gap is generated when the coupling between RG and the BG occurs. The attenuation constant of the infinite periodic structure is predicted by the transfer matrix method, which is compared with the vibration transmittance of a finite periodic structure calculated by the finite element method. Numerical results show that the hybrid-shunting circuits can make the band-gaps wider by appropriately selecting the inductances, negative capacitances, and resistances.展开更多
Periodic arrays of resonant shunted piezoelectric patches are employed to control the wave propagation in a two-dimensional （2D） acoustic metamaterial. The performance is characterized by the finite element method. ...Periodic arrays of resonant shunted piezoelectric patches are employed to control the wave propagation in a two-dimensional （2D） acoustic metamaterial. The performance is characterized by the finite element method. More importantly, we propose an approach to solving the conventional issue of the nonlinear eigenvalue problem, and give a convenient solution to the dispersion properties of 2D metamaterials with periodic arrays of resonant shunts in this article. Based on this modeling method, the dispersion relations of a 2D metamaterial with periodic arrays of resonant shunted piezos are calculated. The results show that the internal resonances of the shunting system split the dispersion curves, thereby forming a locally resonant band gap. However, unlike the conventional locally resonant gap, the vibrations in this locally resonant gap are unable to be completely localized in oscillators consisting of shunting inductors and piezo-patches.展开更多
This study investigated the feasibility of distance protection in extra-high voltage(EHV) networks. In long-distance transmission lines, the distributed parameter characteristic of the EHV network is obvious. When a f...This study investigated the feasibility of distance protection in extra-high voltage(EHV) networks. In long-distance transmission lines, the distributed parameter characteristic of the EHV network is obvious. When a fault occurs far away from the measurement site, the measured impedance might not be directly proportional to the fault distance, and the protection domain of distance protection will be decreased. The detailed theory inferred and proven in this paper reveals that this phenomenon is widespread in EHV transmission lines. The results indicate that the protection domain error is greatly reduced by the application of the shunt reactor. Overall, simulation results show that the proposed method is effective for impedance relay, considering different characteristics, different lengths of lines, and compensation degrees.展开更多
Piezoelectric shunting arrays are employed to control the wave propagation in flexible beams. Contrary to conven- tional symmetric configuration, a substrate beam with anti-symmetric shunting arrays is investigated by...Piezoelectric shunting arrays are employed to control the wave propagation in flexible beams. Contrary to conven- tional symmetric configuration, a substrate beam with anti-symmetric shunting arrays is investigated by adapted transfer matrix method. Compared with symmetric scheme, the anti-symmetric one demonstrates some distinctive characteristics. Primarily, the longitudinal and fiexural waves are coupled, so they are correlated and must be considered simultaneously. Moreover, the attenuation of flexural wave is much stronger in anti-symmetric scenario, while the longitudinal wave demon- strates the converse side. As a result, the anti-symmetric scheme can be utilized to improve the vibration isolation capability of shunting arrays. Finally, the theoretical analyses are validated by finite element simulations.展开更多
In this paper the topology of a four-leg shunt active-power filter (APF) is given. The APF compensates har-monic and reactive power in a three-phase four-wire system. The scheme adopted for control of the four-leg act...In this paper the topology of a four-leg shunt active-power filter (APF) is given. The APF compensates har-monic and reactive power in a three-phase four-wire system. The scheme adopted for control of the four-leg active power filter,a 3-Dimensional Pulse Width Modulation (PWM) technique,is presented. The theoretical deduction of a space vector PWM (SVPWM) algorithm is given in this paper. The paper also analyzes the distribution of the volt-age-space vector of the four-leg converter in αβγ coordinates and describes methods to determine the location of the voltage-space vector and to calculate duration time. Finally,the algorithm is implemented in simulation; the results show that the total harmonic distortion (THD) of the three phase-current waveforms is reduced. The neutral wire current,after compensation,is about 0 A showing that the topology of the four-leg shunt APF is feasible and the proposed scheme is effective.展开更多
Objective: To investigate the imaging features and clinical significance of carbon dioxide digital subtraction angiography (CO2-DSA) in the diagnosis and treatment of hepatocellular carcinoma (HCC). Methods: Both CO2-...Objective: To investigate the imaging features and clinical significance of carbon dioxide digital subtraction angiography (CO2-DSA) in the diagnosis and treatment of hepatocellular carcinoma (HCC). Methods: Both CO2-DSA and conventional DSA were performed in all 47 patients with HCC, and the angio-graphic manifestations of CO2-DSA were compared with those of conventional DSA in the same patients. Results: Peripheral arterial and capillary imaging by CO2-DSA was inferior to that by conventional DSA, although blood pools were well visualized with CO2. Improved visualization of arterioportal shunting (APS) was obtained with CO2-DSA compared with that by conventional angiography. APS was observed in 33 cases by CO2-DSA and in 12 cases by conventional angiography (P<0. 001). Retrograde visualization of the portal vein (PV) trunk and its large branches was demonstrated in 16 cases by CO2-DSA and in 1 case by conventional DSA (P<0. 001). The manifestation of lipiodol retention in the tumors was consistent with CO2-DSA images after TAE in 38 cases, and with those of conventional DSA in 23 cases (P<0. 01). Conclusion: CO2-DSA was superior to conventional DSA in the detection of APS and retrograde visualization of PV system, and the former can provide usefulness information for the treatment planning (chemoembolization) and patient prognosis. Demonstration of APS by CO2-DSA may suggest the presence of intrahepatic metastases.展开更多
Piezoelectric shunt damping has been widely used in vibration suppression, sound absorption, noise elimination, etc. In such applications, the variant elastic constants of piezoelectric materials are the essential par...Piezoelectric shunt damping has been widely used in vibration suppression, sound absorption, noise elimination, etc. In such applications, the variant elastic constants of piezoelectric materials are the essential parameters that determine the performances of the systems, when piezoelectric materials are shunted to normal electrical elements, i.e., resistance, inductance and capacitance, as well as their combinations. In recent years, many researches have demonstrated that the wideband sound absorption or vibration suppression can be realized with piezoelectric materials shunted to negative capacitance. However, most systems using the negative-capacitance shunt circuits show their instabilities in the optimal condition, which are essentially caused by the singular variation properties of elastic constants of piezoelectric materials when shunted to negative capacitance. This paper aims at investigating the effects of negative-capacitance shunt circuits on elastic constants of a piezoelectric ceramic plate through theoretical analyses and experiments, which gives an rational explanation for why negative capacitance shunt circuit is prone to make structure instable. First, the relationships between the elastic constants c11, c33, c55 of the piezoelectric ceramic and the shunt negative capacitance are derived with the piezoelectric constitutive law theoretically. Then, an experimental setup is established to verify the theoretical results through observing the change of elastic constant c55 of the shunted piezoelectric plate with the variation of negative capacitance. The experimental results are in good agreement with the theoretical analyses, which reveals that the instability of the shunt damping system is essentially caused by the singular variation property of the elastic constants of piezoelectric material shunted to negative capacitance.展开更多
In this paper, we prove the existence and the global exponential stability of the unique weighted pseudo almost-periodic solution of shunting inhibitory cellular neural networks with mixed time-varying delays comprisi...In this paper, we prove the existence and the global exponential stability of the unique weighted pseudo almost-periodic solution of shunting inhibitory cellular neural networks with mixed time-varying delays comprising different discrete and distributed time delays. Some sufficient conditions are given for the existence and the global exponential stability of the weighted pseudo almost-periodic solution by employing fixed point theorem and differential inequality techniques. The results of this paper complement the previously known ones. Finally, an illustrative example is given to demonstrate the effectiveness of our results.展开更多
Congenital extrahepatic portosystemic shunt(CEPS),also known as Abernethy malformation,is a rare disorder characterized by the partial or complete diversion of portal blood into systemic veins.CEPS is classified into ...Congenital extrahepatic portosystemic shunt(CEPS),also known as Abernethy malformation,is a rare disorder characterized by the partial or complete diversion of portal blood into systemic veins.CEPS is classified into two types:typeⅠis an end-to-side portocaval shunt,whereas typeⅡis a side-to-side shunt,diverting blood from the portal vein to the inferior vena cava(IVC)(Figure 1).[1]展开更多
Platypnea orthodeoxia syndrome is associated with dyspnea and arterial oxygen desamration accentuated by an upright posture. It can be secondary to an intracardiac shunt. We report a case of platypnea-orthodeoxia synd...Platypnea orthodeoxia syndrome is associated with dyspnea and arterial oxygen desamration accentuated by an upright posture. It can be secondary to an intracardiac shunt. We report a case of platypnea-orthodeoxia syndrome （POS） in a 58-year old male patient who had a pre-existing patent foramen ovale （PFO） and substantial pulmonary pathologies. He was successfully treated by percutaneous transcatheter closure of the PFO. Our case highlights the importance of recognition of this rare syndrome in patients who present with unexplained hy- poxia for whom transcatheter closure of the interatrial shunt can be safely carded out.展开更多
Dear editor,Hepatopulmonary syndrome(HPS)is not uncommon in the setting of liver disease,especially in liver cirrhosis patients.The prevalence of HPS in liver cirrhosis patients varies from 4%to 47%.[1-3]About the def...Dear editor,Hepatopulmonary syndrome(HPS)is not uncommon in the setting of liver disease,especially in liver cirrhosis patients.The prevalence of HPS in liver cirrhosis patients varies from 4%to 47%.[1-3]About the definition of HPS,it is a pulmonary vascular disorder with evidence of intrapulmonary arterial venous shunt.[4]Pulmonary dyspnea and polycythemia are common presentations of HPS.Dyspnea,cyanosis and clubbed fingers were present in most of all cases.Spider nevi is another common clinical feature of patients with HPS.展开更多
An 86-year-old male patient was admitted in our cardiology ward with signs of congestive biventricular heart failure. The patient presented with deteriorating dyspnea on mild exertion and at rest the last days, compat...An 86-year-old male patient was admitted in our cardiology ward with signs of congestive biventricular heart failure. The patient presented with deteriorating dyspnea on mild exertion and at rest the last days, compatible with class NYHA Ⅲ-Ⅳ heart failure, bilateral peripheral oedema, increased NT-proBNP （9198 pg/mL）, mildly elevated Troponin （TnT 64 pg/mL）, interstitial pulmonary oedema and bilateral pleural effusions in chest X ray.展开更多
We present the design, fabrication, and characterization of a barrier-tunable superconducting quantum interference device（SQUID） qubit for the study of Maxwell＇s demon experiment. In this work, a compound Josephson...We present the design, fabrication, and characterization of a barrier-tunable superconducting quantum interference device（SQUID） qubit for the study of Maxwell＇s demon experiment. In this work, a compound Josephson junction（CJJ）radio-frequency（RF）-SQUID qubit with an overdamped resistively shunted direct-current（DC）-SQUID magnetometer is used to continuously monitor the state of the qubit. The circuit is successfully fabricated with the standard Nb/Al-Al Ox/Nb trilayer process of our laboratory and characterized in a low noise measurement system, which is capable of measuring coherent dynamics of superconducting qubits, in an Oxford dilution refrigerator. All circuit parameters are determined accurately by fitting experimental data to theoretical analysis and simulation, which allows us to make a quantitative comparison between the results of the experiment and theory.展开更多
Platypnea-onhodeoxia syndrome （POS） describes a clinical entity of arterial hypoxemia in the upright position associated with dyspnoea, which is relieved by recumbency. The syndrome is caused by an intracardiac or i...Platypnea-onhodeoxia syndrome （POS） describes a clinical entity of arterial hypoxemia in the upright position associated with dyspnoea, which is relieved by recumbency. The syndrome is caused by an intracardiac or intrapulmonary shunt, or ventilation-perfusion mismatching. We describe here the first case of resolving/relapsing POS induced by intracardiac right-to-left shunting that was partly dependent on volume overload.展开更多
The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive(e.g. in the case of depot operations) or highly inefficient(e.g. in indust...The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive(e.g. in the case of depot operations) or highly inefficient(e.g. in industrial railways). These parts are typically managed on-sight, i.e. with no signalling and train protection systems ensuring the freedom of movement. This is possible due to the rather short braking distances of individual vehicles and shunting consists. The present article analyses the braking behaviour of such shunting units. For this purpose, a dedicated model is developed. It is calibrated on published results of brake tests and validated against a high-definition model for lowspeed applications. Based on this model, multiple simulations are executed to obtain a Monte Carlo simulation of the resulting braking distances. Based on the distribution properties and established safety levels, the risk of exceeding certain braking distances is evaluated and maximum braking distances are derived. Together with certain parameters of the system, these can serve in the design and safety assessment of driver assistance systems and automation of these processes.展开更多
基金acknowledge the Fundamental Research Funds for the Central Universities(Grants No 309190112102)the Natural Science Foundation of Jiangsu Province(Grants No BK20200493).
文摘In this paper,a passive muzzle arc control device(PMACD)of the augmented railguns is studied.By discussing its performance at different numbers of extra rails,a parameter optimization model is proposed.Through the calculation model,it is found that the PMACD works well in the simple railgun,which refers to the gun that there is only one pair of rails in the inner bore.The PMACD may decrease the simple railgun’s armature peak current and muzzle arc,but affect its muzzle velocity not much.However,in the augmented railguns it has different characteristics.If the parameters of the PMACD are not selected suitable.It may increase the armature peak current and muzzle arc,but greatly decrease the velocity.The reason for this problem is that the extra rails generate a strong magnetic field in front of the armature,which induces a large current to change the armature current.It is also found that when the resistance and inductance parameters of the PMACD satisfy with the optimization formula,the PMACD can also play a good role in arc suppression in the augmented railguns.Experiments of an augmented railgun with a stainless steel PMACD are carried out to verify this optimization method.Results show that the muzzle arc is obviously controlled.This work may provide a reference for the design of the muzzle arc control device.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.50875255 and 10902123)
文摘Periodic arrays of negative capacitance shunted piezoelectric patches are employed to control the band gaps of phononic beams. The location and the extent of induced band gap depend on the mismatch in impedance generated by each patch. The total impedance mismatch is determined by the added mass and stiffness of each patch as well as the shunting electrical impedance. Therefore, the band gap of the shunted phononic beam can be actively tuned by appropriately selecting the value of negative capacitance. The control of the band gap of phononic beam with negative capacitive shunt is demonstrated numerically by employing transfer matrix method. The result reveals that using negative capacitive shunt to tune the band gap is effective.
基金supported by the National Natural Science Foundation of China(Grant Nos.51275519 and 51175501)
文摘Periodic arrays of hybrid-shunted piezoelectric patches are used to control the band-gaps of phononic metamaterial beams. Passive resistive-inductive （RL） shunting circuits can produce a narrow resonant band-gap （RG）, and active negative capacitive （NC） shunting circuits can broaden the Bragg band-gaps （BGs）. In this article, active NC shunting circuits and passive resonant RL shunting circuits are connected to the same piezoelectric patches in parallel, which are usually called hybrid shunting circuits, to control the location and the extent of the band-gaps. A super-wide coupled band-gap is generated when the coupling between RG and the BG occurs. The attenuation constant of the infinite periodic structure is predicted by the transfer matrix method, which is compared with the vibration transmittance of a finite periodic structure calculated by the finite element method. Numerical results show that the hybrid-shunting circuits can make the band-gaps wider by appropriately selecting the inductances, negative capacitances, and resistances.
基金the National Natural Science Foundation of China(Grant Nos.50905182 and 51175501)
文摘Periodic arrays of resonant shunted piezoelectric patches are employed to control the wave propagation in a two-dimensional （2D） acoustic metamaterial. The performance is characterized by the finite element method. More importantly, we propose an approach to solving the conventional issue of the nonlinear eigenvalue problem, and give a convenient solution to the dispersion properties of 2D metamaterials with periodic arrays of resonant shunts in this article. Based on this modeling method, the dispersion relations of a 2D metamaterial with periodic arrays of resonant shunted piezos are calculated. The results show that the internal resonances of the shunting system split the dispersion curves, thereby forming a locally resonant band gap. However, unlike the conventional locally resonant gap, the vibrations in this locally resonant gap are unable to be completely localized in oscillators consisting of shunting inductors and piezo-patches.
文摘This study investigated the feasibility of distance protection in extra-high voltage(EHV) networks. In long-distance transmission lines, the distributed parameter characteristic of the EHV network is obvious. When a fault occurs far away from the measurement site, the measured impedance might not be directly proportional to the fault distance, and the protection domain of distance protection will be decreased. The detailed theory inferred and proven in this paper reveals that this phenomenon is widespread in EHV transmission lines. The results indicate that the protection domain error is greatly reduced by the application of the shunt reactor. Overall, simulation results show that the proposed method is effective for impedance relay, considering different characteristics, different lengths of lines, and compensation degrees.
基金Project supported by the National Natural Science Foundation of China(Grant No.51322502)
文摘Piezoelectric shunting arrays are employed to control the wave propagation in flexible beams. Contrary to conven- tional symmetric configuration, a substrate beam with anti-symmetric shunting arrays is investigated by adapted transfer matrix method. Compared with symmetric scheme, the anti-symmetric one demonstrates some distinctive characteristics. Primarily, the longitudinal and fiexural waves are coupled, so they are correlated and must be considered simultaneously. Moreover, the attenuation of flexural wave is much stronger in anti-symmetric scenario, while the longitudinal wave demon- strates the converse side. As a result, the anti-symmetric scheme can be utilized to improve the vibration isolation capability of shunting arrays. Finally, the theoretical analyses are validated by finite element simulations.
文摘In this paper the topology of a four-leg shunt active-power filter (APF) is given. The APF compensates har-monic and reactive power in a three-phase four-wire system. The scheme adopted for control of the four-leg active power filter,a 3-Dimensional Pulse Width Modulation (PWM) technique,is presented. The theoretical deduction of a space vector PWM (SVPWM) algorithm is given in this paper. The paper also analyzes the distribution of the volt-age-space vector of the four-leg converter in αβγ coordinates and describes methods to determine the location of the voltage-space vector and to calculate duration time. Finally,the algorithm is implemented in simulation; the results show that the total harmonic distortion (THD) of the three phase-current waveforms is reduced. The neutral wire current,after compensation,is about 0 A showing that the topology of the four-leg shunt APF is feasible and the proposed scheme is effective.
文摘Objective: To investigate the imaging features and clinical significance of carbon dioxide digital subtraction angiography (CO2-DSA) in the diagnosis and treatment of hepatocellular carcinoma (HCC). Methods: Both CO2-DSA and conventional DSA were performed in all 47 patients with HCC, and the angio-graphic manifestations of CO2-DSA were compared with those of conventional DSA in the same patients. Results: Peripheral arterial and capillary imaging by CO2-DSA was inferior to that by conventional DSA, although blood pools were well visualized with CO2. Improved visualization of arterioportal shunting (APS) was obtained with CO2-DSA compared with that by conventional angiography. APS was observed in 33 cases by CO2-DSA and in 12 cases by conventional angiography (P<0. 001). Retrograde visualization of the portal vein (PV) trunk and its large branches was demonstrated in 16 cases by CO2-DSA and in 1 case by conventional DSA (P<0. 001). The manifestation of lipiodol retention in the tumors was consistent with CO2-DSA images after TAE in 38 cases, and with those of conventional DSA in 23 cases (P<0. 01). Conclusion: CO2-DSA was superior to conventional DSA in the detection of APS and retrograde visualization of PV system, and the former can provide usefulness information for the treatment planning (chemoembolization) and patient prognosis. Demonstration of APS by CO2-DSA may suggest the presence of intrahepatic metastases.
文摘Piezoelectric shunt damping has been widely used in vibration suppression, sound absorption, noise elimination, etc. In such applications, the variant elastic constants of piezoelectric materials are the essential parameters that determine the performances of the systems, when piezoelectric materials are shunted to normal electrical elements, i.e., resistance, inductance and capacitance, as well as their combinations. In recent years, many researches have demonstrated that the wideband sound absorption or vibration suppression can be realized with piezoelectric materials shunted to negative capacitance. However, most systems using the negative-capacitance shunt circuits show their instabilities in the optimal condition, which are essentially caused by the singular variation properties of elastic constants of piezoelectric materials when shunted to negative capacitance. This paper aims at investigating the effects of negative-capacitance shunt circuits on elastic constants of a piezoelectric ceramic plate through theoretical analyses and experiments, which gives an rational explanation for why negative capacitance shunt circuit is prone to make structure instable. First, the relationships between the elastic constants c11, c33, c55 of the piezoelectric ceramic and the shunt negative capacitance are derived with the piezoelectric constitutive law theoretically. Then, an experimental setup is established to verify the theoretical results through observing the change of elastic constant c55 of the shunted piezoelectric plate with the variation of negative capacitance. The experimental results are in good agreement with the theoretical analyses, which reveals that the instability of the shunt damping system is essentially caused by the singular variation property of the elastic constants of piezoelectric material shunted to negative capacitance.
文摘In this paper, we prove the existence and the global exponential stability of the unique weighted pseudo almost-periodic solution of shunting inhibitory cellular neural networks with mixed time-varying delays comprising different discrete and distributed time delays. Some sufficient conditions are given for the existence and the global exponential stability of the weighted pseudo almost-periodic solution by employing fixed point theorem and differential inequality techniques. The results of this paper complement the previously known ones. Finally, an illustrative example is given to demonstrate the effectiveness of our results.
基金funded by the Tianjin Health Technology Project(20188)Peking Union Medical Foundation-Ruiyi Emergency Medical Research Fund(R2020010)。
文摘Congenital extrahepatic portosystemic shunt(CEPS),also known as Abernethy malformation,is a rare disorder characterized by the partial or complete diversion of portal blood into systemic veins.CEPS is classified into two types:typeⅠis an end-to-side portocaval shunt,whereas typeⅡis a side-to-side shunt,diverting blood from the portal vein to the inferior vena cava(IVC)(Figure 1).[1]
文摘Platypnea orthodeoxia syndrome is associated with dyspnea and arterial oxygen desamration accentuated by an upright posture. It can be secondary to an intracardiac shunt. We report a case of platypnea-orthodeoxia syndrome （POS） in a 58-year old male patient who had a pre-existing patent foramen ovale （PFO） and substantial pulmonary pathologies. He was successfully treated by percutaneous transcatheter closure of the PFO. Our case highlights the importance of recognition of this rare syndrome in patients who present with unexplained hy- poxia for whom transcatheter closure of the interatrial shunt can be safely carded out.
文摘Dear editor,Hepatopulmonary syndrome(HPS)is not uncommon in the setting of liver disease,especially in liver cirrhosis patients.The prevalence of HPS in liver cirrhosis patients varies from 4%to 47%.[1-3]About the definition of HPS,it is a pulmonary vascular disorder with evidence of intrapulmonary arterial venous shunt.[4]Pulmonary dyspnea and polycythemia are common presentations of HPS.Dyspnea,cyanosis and clubbed fingers were present in most of all cases.Spider nevi is another common clinical feature of patients with HPS.
文摘An 86-year-old male patient was admitted in our cardiology ward with signs of congestive biventricular heart failure. The patient presented with deteriorating dyspnea on mild exertion and at rest the last days, compatible with class NYHA Ⅲ-Ⅳ heart failure, bilateral peripheral oedema, increased NT-proBNP （9198 pg/mL）, mildly elevated Troponin （TnT 64 pg/mL）, interstitial pulmonary oedema and bilateral pleural effusions in chest X ray.
基金supported by the National Natural Science Foundation of China(Grant No.11653001)the National Basic Research Program of China(Grant No.2011CBA00304)+1 种基金the Tsinghua University Initiative Scientific Research Program,China(Grant No.20131089314)the Zhejiang Tianjingsheng Foundation,China,for Student Assistantships(Gang Li and Hao Li)
文摘We present the design, fabrication, and characterization of a barrier-tunable superconducting quantum interference device（SQUID） qubit for the study of Maxwell＇s demon experiment. In this work, a compound Josephson junction（CJJ）radio-frequency（RF）-SQUID qubit with an overdamped resistively shunted direct-current（DC）-SQUID magnetometer is used to continuously monitor the state of the qubit. The circuit is successfully fabricated with the standard Nb/Al-Al Ox/Nb trilayer process of our laboratory and characterized in a low noise measurement system, which is capable of measuring coherent dynamics of superconducting qubits, in an Oxford dilution refrigerator. All circuit parameters are determined accurately by fitting experimental data to theoretical analysis and simulation, which allows us to make a quantitative comparison between the results of the experiment and theory.
文摘Platypnea-onhodeoxia syndrome （POS） describes a clinical entity of arterial hypoxemia in the upright position associated with dyspnoea, which is relieved by recumbency. The syndrome is caused by an intracardiac or intrapulmonary shunt, or ventilation-perfusion mismatching. We describe here the first case of resolving/relapsing POS induced by intracardiac right-to-left shunting that was partly dependent on volume overload.
基金funding of the SAMIRA project by the European Regional Development Fund under grant number 0801689
文摘The first and last mile of a railway journey, in both freight and transit applications, constitutes a high effort and is either non-productive(e.g. in the case of depot operations) or highly inefficient(e.g. in industrial railways). These parts are typically managed on-sight, i.e. with no signalling and train protection systems ensuring the freedom of movement. This is possible due to the rather short braking distances of individual vehicles and shunting consists. The present article analyses the braking behaviour of such shunting units. For this purpose, a dedicated model is developed. It is calibrated on published results of brake tests and validated against a high-definition model for lowspeed applications. Based on this model, multiple simulations are executed to obtain a Monte Carlo simulation of the resulting braking distances. Based on the distribution properties and established safety levels, the risk of exceeding certain braking distances is evaluated and maximum braking distances are derived. Together with certain parameters of the system, these can serve in the design and safety assessment of driver assistance systems and automation of these processes.
