BACKGROUND Retrocecal appendicitis,the most common anatomical type,presents diagnostic and surgical challenges.Single-port laparoscopic appendectomy(SPLA)has been proposed as an alternative to multi-port laparoscopic ...BACKGROUND Retrocecal appendicitis,the most common anatomical type,presents diagnostic and surgical challenges.Single-port laparoscopic appendectomy(SPLA)has been proposed as an alternative to multi-port laparoscopic appendectomy(MPLA)with advancements in minimally invasive surgery.However,few studies have compared the perioperative outcomes between the SPLA and MPLA for retrocecal appendicitis.AIM To compare the efficacy and safety between the SPLA and MPLA in treating retrocecal appendicitis,focusing on perioperative outcomes.METHODS This retrospective study analyzed data from 1041 patients who underwent SPLA or MPLA at Konyang University Hospital between October 2011 and February 2023.Propensity score matching(PSM)was used to minimize selection bias,resulting in 235 patients in each group.Additionally,non-inferiority tests,post-hoc analysis,and multivariable regression analysis were performed to validate the results and assess factors affecting postoperative outcomes.RESULTS After PSM,SPLA showed shorter operation time(43.8±15.8 minutes vs 51.6±18.7 minutes;P<0.001)and lower estimated blood loss(EBL,6.5±7.8 mL vs 8.6±8.3 mL;P<0.001)than MPLA.No significant differences were observed in complications,pain scores,or length of hospital stay.SPLA was not inferior to MPLA in the main outcomes,except for the complication rate,where statistical power was insufficient.Multivariable regression confirmed SPLA as an independent factor for operation time and EBL.CONCLUSION SPLA is more feasible than MPLA for retrocecal appendicitis,offering advantages in operation time and estimated blood loss.This study supports SPLA as a viable alternative that enhances postoperative recovery.展开更多
Very high frequency(VHF) photocathode guns have excellent performance and are being increasingly selected as electron sources for high-repetition-rate X-ray free-electron lasers. As a highly loaded quality factor cavi...Very high frequency(VHF) photocathode guns have excellent performance and are being increasingly selected as electron sources for high-repetition-rate X-ray free-electron lasers. As a highly loaded quality factor cavity, the VHF gun requires high stability in the amplitude and phase of the cavity field. However, the gun is microwave powered by two solid-state power sources through two separate power couplers. The input difference between the two power couplers will influence the stability of the cavity field. To systematically study this influence and obtain measurement formulae, a multi-port VHF gun LCR circuit model is built and analyzed. During the warm-up condition, the cavity structure will be deformed due to the large-scale change in the cavity temperature. Then, the deformation will result in cavity resonant frequency changes. To prevent the mechanic tuner from suffering damages due to the frequent and long-distance movement for correcting the cavity resonant frequency, a self-excited loop(SEL) control system is considered for changing the loop phase and make the loop frequency follow the resonant frequency. In this study, a steady-state model of the VHF gun cavity is built for obtaining the optimal input coupler coefficient and the stability requirement of the forward voltage. Then, the generator-driven resonator and SEL control system, which combine with the VHF multiport modeling, are modeled and simulated. The simulated results show that the SEL system can perfectly operate in the process of condition and warm-up.展开更多
BACKGROUND Minimally invasive pancreatic surgery via the multi-port approach has become a primary surgical method for distal pancreatectomy(DP)due to its advantages of lower wound pain and superior cosmetic results.So...BACKGROUND Minimally invasive pancreatic surgery via the multi-port approach has become a primary surgical method for distal pancreatectomy(DP)due to its advantages of lower wound pain and superior cosmetic results.Some studies have applied reduced-port techniques for DP in an attempt to enhance cosmetic outcomes due to the minimally invasive effects.Numerous recent review studies have compared multi-port laparoscopic DP(LDP)and multi-port robotic DP(RDP);most of these studies concluded multi-port RDP is more beneficial than multi-port LDP for spleen preservation.However,there have been no comprehensive reviews of the value of reduced-port LDP and reduced-port RDP.AIM To search for and review the studies on spleen preservation and the clinical outcomes of minimally invasive DP that compared reduced-port DP surgery with multi-port DP surgery.METHODS The PubMed medical database was searched for articles published between 2013 and 2022.The search terms were implemented using the following Boolean search algorithm:(“distal pancreatectomy”OR“left pancreatectomy”OR“peripheral pancreatic resection”)AND(“reduced-port”OR“single-site”OR“single-port”OR“dual-incision”OR“single-incision”)AND(“spleen-preserving”OR“spleen preservation”OR“splenic preservation”).A literature review was conducted to identify studies that compared the perioperative outcomes of reduced-port LDP and reduced-port RDP.RESULTS Fifteen articles published in the period from 2013 to 2022 were retrieved using three groups of search terms.Two studies were added after manually searching the related papers.Finally,10 papers were selected after removing case reports(n=3),non-English language papers(n=1),technique papers(n=1),reviews(n=1),and animal studies(n=1).The common items were defined as items reported in more than five papers,and data on these common items were extracted from all papers.The ten studies included a total of 337 patients(females/males:231/106)who underwent DP.In total,166 patients(females/males,106/60)received multi-port LDP,126(females/males,90/36)received reduced-port LDP,and 45(females/males,35/10)received reduced-port RDP.CONCLUSION Reduced-port RDP leads to a lower intraoperative blood loss,a lower postoperative pancreatic fistula rate,and shorter hospital stay and follow-up duration,but has a lower spleen preservation rate.展开更多
A new simple method in which arbitrary transfer function matrix is realized withactive multiple port network instead of computer simulating is proposed. The active multipleport network is carried on through state feed...A new simple method in which arbitrary transfer function matrix is realized withactive multiple port network instead of computer simulating is proposed. The active multipleport network is carried on through state feedback and state cross output for RC ladder network.The main process is to determine coefficients of each adder. Finally, an example is given forillustration.展开更多
For Hall plates, the ratio of signal over thermal noise is determined by material properties, thickness, layout geometry, magnetic field, and the electric power at which the plate is operated. For traditional Hall pla...For Hall plates, the ratio of signal over thermal noise is determined by material properties, thickness, layout geometry, magnetic field, and the electric power at which the plate is operated. For traditional Hall plates with four contacts, the optimum choice is a symmetrical device with medium-sized contacts. This paper shows that the signal-to-noise-ratio (<em>SNR</em>) can be further increased by up to 90% for Hall plates with more than four contacts. Supply currents flow through several pairs of contacts, while a signal conditioning circuit taps output voltages at all pairs of contacts and sums them up. We compute the total thermal noise of the sum of correlated noise voltages and relate it to the total magnetic sensitivity. We also prove that for electrically linear devices a spinning current scheme cancels out zero point errors (offset errors) in a strict sense. All our investigations use the definite resistance matrix of multi-port Hall plates. We develop an analytical theory based on recent advances in the theory of Hall plates, and then we compute the integrals and matrices numerically for symmetrical Hall plates with six to 40 contacts. We also present measurements in accordance with our theory.展开更多
While modeling a power supply system for an electric railway traction, knowing equivalent circuits of locomotives supplied this way is an essential issue. In alternating current traction, it is important to diagnose i...While modeling a power supply system for an electric railway traction, knowing equivalent circuits of locomotives supplied this way is an essential issue. In alternating current traction, it is important to diagnose inter alia processes taking place in transformers installed on electric vehicles. This article presents specific phenomena occurring during the work of mono-phase, multi-winding, multisystem （systems AC： 50 Hz, 16.7 Hz） laboratory traction transformer. It also shows difficulties encountered during the process of identifying multi-port equivalent scheme＇s elements of the described device, in which a construction defect occurs.展开更多
This paper presents a framework of the distributed concurrent multi-port-testing test system (CMPT-TS) for IP routers under development at Sichuan Network Communication Key Laboratory. Having analyzed the actuality of...This paper presents a framework of the distributed concurrent multi-port-testing test system (CMPT-TS) for IP routers under development at Sichuan Network Communication Key Laboratory. Having analyzed the actuality of concurrent testing for routers, this paper develops a distributed architecture of CMPT-TS and discusses its functional components in detail. Moreover, a new test definition language, CMPT definition language, is also introduced simply.展开更多
The voltage source converter based multi-terminal high-voltage direct current(VSC-MTDC)system has attracted much attention because it can achieve the interconnection between AC grids.However,the initial phases and sho...The voltage source converter based multi-terminal high-voltage direct current(VSC-MTDC)system has attracted much attention because it can achieve the interconnection between AC grids.However,the initial phases and short-circuit ratios(SCRs)of the interconnected AC grids cause the steady-state phases(SSPs)of AC ports in the VSC-MTDC system to be different.This can lead to the issues such as mismatches in multiple converter reference frame systems,potentially causing inaccuracies in stability analysis when this phenomenon is disregarded.To address the aforementioned issues,a multi-port network model of the VSC-MTDC system,which considers the SSPs of the AC grids and AC ports,is derived by multiplying the port models of different subsystems(SSs).The proposed multi-port network model can accurately describe the transmission characteristics between the input and output ports of the system.Additionally,this model facilitates accurate analysis of the system stability.Furthermore,it identifies the key factors affecting the system stability.Ultimately,the accuracy of the proposed multi-port network model and the analysis of key factors are verified by time-domain simulations.展开更多
文摘BACKGROUND Retrocecal appendicitis,the most common anatomical type,presents diagnostic and surgical challenges.Single-port laparoscopic appendectomy(SPLA)has been proposed as an alternative to multi-port laparoscopic appendectomy(MPLA)with advancements in minimally invasive surgery.However,few studies have compared the perioperative outcomes between the SPLA and MPLA for retrocecal appendicitis.AIM To compare the efficacy and safety between the SPLA and MPLA in treating retrocecal appendicitis,focusing on perioperative outcomes.METHODS This retrospective study analyzed data from 1041 patients who underwent SPLA or MPLA at Konyang University Hospital between October 2011 and February 2023.Propensity score matching(PSM)was used to minimize selection bias,resulting in 235 patients in each group.Additionally,non-inferiority tests,post-hoc analysis,and multivariable regression analysis were performed to validate the results and assess factors affecting postoperative outcomes.RESULTS After PSM,SPLA showed shorter operation time(43.8±15.8 minutes vs 51.6±18.7 minutes;P<0.001)and lower estimated blood loss(EBL,6.5±7.8 mL vs 8.6±8.3 mL;P<0.001)than MPLA.No significant differences were observed in complications,pain scores,or length of hospital stay.SPLA was not inferior to MPLA in the main outcomes,except for the complication rate,where statistical power was insufficient.Multivariable regression confirmed SPLA as an independent factor for operation time and EBL.CONCLUSION SPLA is more feasible than MPLA for retrocecal appendicitis,offering advantages in operation time and estimated blood loss.This study supports SPLA as a viable alternative that enhances postoperative recovery.
文摘Very high frequency(VHF) photocathode guns have excellent performance and are being increasingly selected as electron sources for high-repetition-rate X-ray free-electron lasers. As a highly loaded quality factor cavity, the VHF gun requires high stability in the amplitude and phase of the cavity field. However, the gun is microwave powered by two solid-state power sources through two separate power couplers. The input difference between the two power couplers will influence the stability of the cavity field. To systematically study this influence and obtain measurement formulae, a multi-port VHF gun LCR circuit model is built and analyzed. During the warm-up condition, the cavity structure will be deformed due to the large-scale change in the cavity temperature. Then, the deformation will result in cavity resonant frequency changes. To prevent the mechanic tuner from suffering damages due to the frequent and long-distance movement for correcting the cavity resonant frequency, a self-excited loop(SEL) control system is considered for changing the loop phase and make the loop frequency follow the resonant frequency. In this study, a steady-state model of the VHF gun cavity is built for obtaining the optimal input coupler coefficient and the stability requirement of the forward voltage. Then, the generator-driven resonator and SEL control system, which combine with the VHF multiport modeling, are modeled and simulated. The simulated results show that the SEL system can perfectly operate in the process of condition and warm-up.
基金Chung Shan Medical University,No.15I42440Feng Chia University/Chung Shan Medical University,No.FCU/CSMU104-001and Taiwan National Science and Technology Council,No.111-2314-B-035-001-MY3 and No.110-2221-E-035-016.
文摘BACKGROUND Minimally invasive pancreatic surgery via the multi-port approach has become a primary surgical method for distal pancreatectomy(DP)due to its advantages of lower wound pain and superior cosmetic results.Some studies have applied reduced-port techniques for DP in an attempt to enhance cosmetic outcomes due to the minimally invasive effects.Numerous recent review studies have compared multi-port laparoscopic DP(LDP)and multi-port robotic DP(RDP);most of these studies concluded multi-port RDP is more beneficial than multi-port LDP for spleen preservation.However,there have been no comprehensive reviews of the value of reduced-port LDP and reduced-port RDP.AIM To search for and review the studies on spleen preservation and the clinical outcomes of minimally invasive DP that compared reduced-port DP surgery with multi-port DP surgery.METHODS The PubMed medical database was searched for articles published between 2013 and 2022.The search terms were implemented using the following Boolean search algorithm:(“distal pancreatectomy”OR“left pancreatectomy”OR“peripheral pancreatic resection”)AND(“reduced-port”OR“single-site”OR“single-port”OR“dual-incision”OR“single-incision”)AND(“spleen-preserving”OR“spleen preservation”OR“splenic preservation”).A literature review was conducted to identify studies that compared the perioperative outcomes of reduced-port LDP and reduced-port RDP.RESULTS Fifteen articles published in the period from 2013 to 2022 were retrieved using three groups of search terms.Two studies were added after manually searching the related papers.Finally,10 papers were selected after removing case reports(n=3),non-English language papers(n=1),technique papers(n=1),reviews(n=1),and animal studies(n=1).The common items were defined as items reported in more than five papers,and data on these common items were extracted from all papers.The ten studies included a total of 337 patients(females/males:231/106)who underwent DP.In total,166 patients(females/males,106/60)received multi-port LDP,126(females/males,90/36)received reduced-port LDP,and 45(females/males,35/10)received reduced-port RDP.CONCLUSION Reduced-port RDP leads to a lower intraoperative blood loss,a lower postoperative pancreatic fistula rate,and shorter hospital stay and follow-up duration,but has a lower spleen preservation rate.
文摘A new simple method in which arbitrary transfer function matrix is realized withactive multiple port network instead of computer simulating is proposed. The active multipleport network is carried on through state feedback and state cross output for RC ladder network.The main process is to determine coefficients of each adder. Finally, an example is given forillustration.
文摘For Hall plates, the ratio of signal over thermal noise is determined by material properties, thickness, layout geometry, magnetic field, and the electric power at which the plate is operated. For traditional Hall plates with four contacts, the optimum choice is a symmetrical device with medium-sized contacts. This paper shows that the signal-to-noise-ratio (<em>SNR</em>) can be further increased by up to 90% for Hall plates with more than four contacts. Supply currents flow through several pairs of contacts, while a signal conditioning circuit taps output voltages at all pairs of contacts and sums them up. We compute the total thermal noise of the sum of correlated noise voltages and relate it to the total magnetic sensitivity. We also prove that for electrically linear devices a spinning current scheme cancels out zero point errors (offset errors) in a strict sense. All our investigations use the definite resistance matrix of multi-port Hall plates. We develop an analytical theory based on recent advances in the theory of Hall plates, and then we compute the integrals and matrices numerically for symmetrical Hall plates with six to 40 contacts. We also present measurements in accordance with our theory.
文摘While modeling a power supply system for an electric railway traction, knowing equivalent circuits of locomotives supplied this way is an essential issue. In alternating current traction, it is important to diagnose inter alia processes taking place in transformers installed on electric vehicles. This article presents specific phenomena occurring during the work of mono-phase, multi-winding, multisystem （systems AC： 50 Hz, 16.7 Hz） laboratory traction transformer. It also shows difficulties encountered during the process of identifying multi-port equivalent scheme＇s elements of the described device, in which a construction defect occurs.
文摘This paper presents a framework of the distributed concurrent multi-port-testing test system (CMPT-TS) for IP routers under development at Sichuan Network Communication Key Laboratory. Having analyzed the actuality of concurrent testing for routers, this paper develops a distributed architecture of CMPT-TS and discusses its functional components in detail. Moreover, a new test definition language, CMPT definition language, is also introduced simply.
基金supported by the National Natural Science Key Foundation of China(No.51937001)in part by the Fundamental Research Funds for the Central Universities(No.2023CDJXY-029)。
文摘The voltage source converter based multi-terminal high-voltage direct current(VSC-MTDC)system has attracted much attention because it can achieve the interconnection between AC grids.However,the initial phases and short-circuit ratios(SCRs)of the interconnected AC grids cause the steady-state phases(SSPs)of AC ports in the VSC-MTDC system to be different.This can lead to the issues such as mismatches in multiple converter reference frame systems,potentially causing inaccuracies in stability analysis when this phenomenon is disregarded.To address the aforementioned issues,a multi-port network model of the VSC-MTDC system,which considers the SSPs of the AC grids and AC ports,is derived by multiplying the port models of different subsystems(SSs).The proposed multi-port network model can accurately describe the transmission characteristics between the input and output ports of the system.Additionally,this model facilitates accurate analysis of the system stability.Furthermore,it identifies the key factors affecting the system stability.Ultimately,the accuracy of the proposed multi-port network model and the analysis of key factors are verified by time-domain simulations.
