Development of a high-repetition-rate lumped-inductance kicker magnet prototype for the beam switchyard of SHINE

The Shanghai high-repetition-rate X-ray free-electron laser and extreme light facility(SHINE)operates at a maximum repetition rate of 1 MHz.Kicker magnets are key components that distribute electron bunches into three different undulator lines in a bunch-by-bunch mode.The kicker field width must be less than the time interval between bunches.A lumpedinductance kicker prototype was developed using a vacuum chamber with a single-turn coil.The full magnetic field strength was 0.005 T.This paper presents the requirements,design considerations,design parameters,magnetic field calculations,and measurements of the kicker magnets.The relevant experimental results are also presented.The pulse width of the magnetic field was approximately 600 ns,and the maximum operation repetition rate was 1 MHz.The developed kicker satisfies the requirements for the SHINE project.Finally,numerous recommendations for the future optimization of kicker magnets are provided.

contrast enhanced computed tomography and reconstruction of hepatic vascular system for transjugular intrahepatic portal systemic shunt puncture path planning

AIM: To describe a method for the transjugular intrahepatic portal systemic shunt(TIPS) placement performed with the aid of contrast-enhanced computed tomography(CECT) and three-dimensional reconstructed vascular images(3D RVIs), and to assess its safety and effectiveness. METHODS: Four hundred and ninety patients were treated with TIPS between January 2005 and December 2012. All patients underwent liver CECT and reconstruction of 3D RVIs of the right hepatic vein to portal vein(PV) prior to the operation. The 3D RVIs were carefully reviewed to plan the puncture path fromthe start to target points for needle pass through the PV in the TIPS procedure. R E S U LTS :The improved TIPS procedure was successful in 483(98.6%) of the 490 patients. The number of punctures attempted was one in 294(60%) patients, 2 to 3 in 147(30%) patients, 4 to 6 in 25(5.1%) patients and more than 6 in 17(3.5%) patients. Seven patients failed. Of the 490 patients, 12 had punctures into the artery, 15 into the bile duct, eight into the gallbladder, and 18 through the liver capsule. Analysis of the portograms from the 483 successful cases indicated that the puncture points were all located distally to the PV bifurcation on anteroposterior images, while the points were located proximally to the bifurcation in the three cases with intraabdominal bleeding. The complications included three cases of bleeding, of whom one died and two needed surgery. CONCLUSION: Use of CECT and 3D RVIs to plan the puncture path for TIPS procedure is safe, simple and effective for clinical use.

SAPT:a synchrotron-based proton therapy facility in Shanghai

Because of its excellent dose distribution,proton therapy is becoming increasingly popular in the medical application of cancer treatment.A synchrotron-based proton therapy facility was designed and constructed in Shanghai.The synchrotron,beam delivery system,and other technical systems were commissioned and reached their expected performances.After a clinical trial of 47 patients was finished,the proton therapy facility obtained a registration certificate from the National Medical Products Administration.The characteristics of the accelerator and treatment systems are described in this article.

Clinical effects and complications of TIPS for portal hypertension due to cirrhosis:A single center

AIM:To determine the clinical effects and complications of transjugular intrahepatic portosystemic shunt(TIPS)for portal hypertension due to cirrhosis.METHODS:Two hundred and eighty patients with portal hypertension due to cirrhosis who underwent TIPS were retrospectively evaluated.Portal trunk pressure was measured before and after surgery.The changes in hemodynamics and the condition of the stent were assessed by ultrasound and the esophageal and fundic veins observed endoscopically.RESULTS:The success rate of TIPS was 99.3%.The portal trunk pressure was 26.8±3.6 cmH2O after surgery and 46.5±3.4 cmH2O before surgery(P<0.01).The velocity of blood flow in the portal vein increased.The internal diameters of the portal and splenic veins were reduced.The short-term hemostasis rate was100%.Esophageal varices disappeared completely in68%of patients and were obviously reduced in 32%.Varices of the stomach fundus disappeared completely in 80%and were obviously reduced in 20%of patients.Ascites disappeared in 62%,were markedly reduced in 24%,but were still apparent in 14%of patients.The total effective rate of ascites reduction was 86%.Hydrothorax completely disappeared in 100%of patients.The incidence of post-operative stent stenosis was 24%at 12 mo and 34%at 24 mo.The incidence of post-operative hepatic encephalopathy was 12%at3 mo,17%at 6 mo and 19%at 12 mo.The incidence of post-operative recurrent hemorrhage was 9%at 12mo,19%at 24 mo and 35%at 36 mo.The cumulative survival rate was 86%at 12 mo,81%at 24 mo,75%at 36 mo,57%at 48 mo and 45%at 60 mo.CONCLUSION:TIPS can effectively lower portal hypertension due to cirrhosis.It is significantly effective for hemorrhage of the digestive tract due to rupture of esophageal and fundic veins and for ascites and hydrothorax caused by portal hypertension.

Application of Quality Control Circle Activity in Improving Effectiveness of Drug Intervention in Lung Cancer Patients with Moderate to Severe Pain

Objective:Lung cancer has the highest incidence and mortality of all malignant tumors in China.Cancer pain dramatically affects patients’comfort level,causing insomnia,anorexia,anxiety,fear,depression,and a decline in the quality of life(QOL).The literature suggests a shortage of adequate cancer pain management for 59.1% of patients in China.The quality control circle(QCC)activity reflects the people-oriented core idea of management.This study aimed to assess the efficacy of QCC in enhancing the effectiveness of drug interventions in lung cancer patients with moderate to severe pain.Methods:From January 2019 to July 2019,lung cancer patients with moderate to severe pain were treated with drugs.The total number of drug interventions was 3072.A QCC activity was performed following the ten steps of the plan-do-check-act(PDCA)model.The reasons for the poor effectiveness of drug intervention in lung cancer patients with moderate to severe pain were analyzed.Countermeasures were designed to improve the effectiveness of drug intervention,including setting up a pain college,writing a medication education manual,and formulating operational rules for the administration of narcotic drugs.The effectiveness of drug intervention in lung cancer patients with moderate to severe pain and activity ability scores of QCC members were analyzed statistically before and after QCC activity.The effectiveness of drug intervention was investigated and compared before and after establishing the QCC.Results:After establishing the PDCA model,the effectiveness of drug intervention for moderate to severe pain in lung cancer patients increased from 56.28% to 85.29%.Members had significant improvement in problem-solving ability,responsibility,communication,coordination,self-confidence,team cohesion,enthusiasm,QCC skills,and harmony.Conclusion:QCC activity can significantly improve the efficiency of drug intervention in lung cancer patients with moderate to severe pain and their quality of life.

Interference effects of two and three super-tall buildings under wind action

Most previous investigations on interference effects of tall buildings under wind actions focused on the wind induced interference effects between two buildings,and the interference effects of three or more buildings have seldom been studied so far due to the huge workload involved in experiments and data processing.In this paper,mean and dynamic force/response interference effects and peak wind pressure interference effects of two and three tall buildings,especially the three-building configuration,are investigated through a series of wind tunnel tests on typical tall building models using high frequency force balance technique and wind pressure measurements.Furthermore,the present paper focuses on the effects of parameters,including breadth ratio and height ratio of the buildings and terrain category,on the interference factors and derives relevant regression results for the interference factors.

Application of two-phase helical CT in liver neoplasms

Objective: To assess the value of helical CT in the di- agnosis of liver diseases. Methods: 59 patients with different liver diseases were examined by two-phase or multi-phase dynamic helical CT. Results: Small hepatocellular carcinoma showed a higher density in the arterial phase, and a lower den- sity in the portal vein phase. Large hepatic carcino- ma showed a mixed pattern of higher-density in the arterial phase, and a lower density in the portal vein phase. Metastasis carcinoma showed an 'oxeye sign' in the portal vein phase. Hemangioma was not obvi- ously enhanced in the early arterial phase, marginal- ly enhanced in the arterial phase, and equally-densed in the balanced phase. Conclusion: Two-phase helical CT is of value in im- proving the detection rate of or determining the fea- tures of hepatic diseases by two-phase helical dyna- mic scan (2.0-3.0 ml/s speed, and delay time 25- 30 s and 70-85 s).

Wind Pressures on Structures by Proper Orthogonal Decomposition

Proper orthogonal decomposition （POD） is an effective statistical technique for data reduction and feature extraction of the random field including the wind field. This paper introduces the theory of the POD and illustrates engineering of structures. Using the POD technique, it is shown that wind pressure data can be accurately reconstructed with a limited number of modes using the wind pressure data from wind tunnel test. Comparing the reconstructed values by POD with the original measured values from the wind tunnel test both in the time and frequency domains, it is concluded that the proper orthogonal decomposition（POD） is an efficient and practical technique for deriving the random wind pressure field from limited known data as shown in the pitched roof example in this paper.

Analysis and optimization of high-power pulse transformer for SXFEL

A C-band accelerator structure was used to accelerate electrons at the Shanghai soft X-ray free-electron laser test facility (SXFEL-TF) in Shanghai Institute of Applied Physics (SINAP). The microwave system of this accelerator structure used a 110 MW pulse modulator and a klystron (PV-5050) to provide the power supply. A pulse transformer is a crucial device in a modulator klystron system and plays significant roles in voltage level transformation, matching impedances, and polarity inversion. This study presents the optimization of a high-voltage pulse transformer. The design considerations of reducing flattop ringing and flattop droop, and shortening leading edge are provided. The model simulation, mechanical design, and the relevant experimental results are also presented.

Isolation and Purification of Antibacterial Peptides from Mussel

[ Objective ] This study aimed to extract antibacterial peptides from mussel. [ Method ] Blue mussels were used as raw materials for direct extraction of antibacterial peptides by using O. 5 % acetic acid, and the antibacterial peptides were isolated and purified by Sephacryl S-100 polyacrylamide gel chromatography. The fractions were collected for measurement of antibacterial activity and minimum inhibitory concentration for a variety of bacterial species by filter paper diffusion assay. Molecular weight of the antibacterial peptides was determined by SDS-PAGE. Variation of antibacterial activity of antibacterial peptides was measured at 100 ~C under conditions of different processing time and different pH. [ Result] The O. 5% acetic acid was used for crude extraction of antibacterial peptides as extrac- tion solution and led to relatively high extraction efficiency. By using Sephacryl S-100, the antibacterial peptides could be purified as a single substance. The isola- ted and purified antibacterial peptides of mussel had relatively strong antibacterial properties with molecular weight of 5 908, showing heat-resistance acid-alkaline resistance. [ Conclusion] This study laid the theoretical foundation for large-scale production of antibacterial peotides.

WiFace:A Secure GeoSocial Networking System Using Wi-Fi Based Multihop MANET

A number of mobile Online Social Networking （OSN） services have appeared in the market in recent times. While most mobile systems benefit greatly from cloud services, centralized servers and communications infrastructure is not always available. Nor are location-based services offered to mobile devices without GPS. To take advantage of cloud and to address these problems, a Wi-Fi based multihop networking system called MoNet is proposed. On top of MONET we propose a privacy-aware geosocial networking service called WiFace. Where there is no infrastructure, a distributed content sharing protocol significantly shortens the relay path, reduces conflicts, and improves data availability. Furthermore, a security mechanism is developed to protect privacy. Comprehensive experiments performed on MoNet show that the system is more than sufficient to support social networking and even audio and video applications.

The main protease of SARS-CoV-2 downregulates innate immunity via a translational repression

Dear Editor,SARS-CoV-2 is the etiological cause of COVID-19.RIG-I-like receptor(RLR)signaling pathway appeared to be responsible for SARS-CoV-2 induced IFN,1 a major antiviral pathway.IFN deficiency2,3 was identified to be a significant risk factor of severe COVID-19,highlighting an important role of IFN in the defense against SARS-CoV-2 and in the pathogenesis of severe COVID-19.

Simulation of steel beam under ceiling jet based on a wind–fire–structure coupling model

For localized fires, it is necessary to consider the thermal and mechanical responses of building elements subject to uneven heating under the influence of wind. In this paper, the thermomechanical phenomena experienced by a ceiling jet and I-beam in a structural fire were simulated. Instead of applying the concept of adiabatic surface temperature (AST) to achieve fluid–structure coupling, this paper proposes a new computational fluid dynamics–finite element method numerical simulation that combines wind, fire, thermal, and structural analyses. First, to analyze the velocity and temperature distributions, the results of the numerical model and experiment were compared in windless conditions, showing good agreement. Vortices were found in the local area formed by the upper and lower flanges of the I-beam and the web, generating a local high-temperature zone and enhancing the heat transfer of convection. In an incoming-flow scenario, the flame was blown askew significantly;the wall temperature was bimodally distributed in the axial direction. The first temperature peak was mainly caused by radiative heat transfer, while the second resulted from convective heat transfer. In terms of mechanical response, the yield strength degradation in the highest-temperature region in windless conditions was found to be significant, thus explaining the stress distribution of steel beams in the fire field. The mechanical response of the overall elements considering the incoming flows was essentially elastic.

Experimental study of wind loads on gable roofs of low-rise buildings with overhangs

Gable roofs with overhangs （eaves） are the common constructions of low-rise buildings on the southeastern coast of China, and they were vulnerable to typhoons from experience. The wind pressure distributions on gable roofs of low-rise buildings are investigated by a series of wind tunnel tests which consist of 99 test cases with various roof pitches, height-depth ratios and width-depth ratios. The block pressure coefficients and worst negative （block） pressure coefficients on different roof regions of low-rise buildings are proposed for the main structure and building envelope, respectively. The effects of roof pitch, height-depth ratio, and width-depth ratio on the pressure coefficients of each region are analyzed in detail. In addition, the pressure coefficients on the roofs for the main structure and building envelope are fitted according to roof pitch, height-depth ratio and width-depth ratio of the low-rise building. Meanwhile, the rationality of the fitting formulas is verified by comparing the fitting results with the codes of different countries. Lastly, the block pressure coefficients and worst negative pressure coefficients are recommended to guide the design of low-rise buildings in typhoon area and act as references for the future＇s modification of wind load codes.

Probabilistic Modeling and Optimization of Real-Time Protocol for Multifunction Vehicle Bus

In this paper, we present the modeling and optimization of a Real-Time Protocol（RTP） used in Train Communication Networks（TCN）. In the proposed RTP, message arbitration is represented by a probabilistic model and the number of arbitration checks is minimized by using the probability of device activity. Our optimized protocol is fully compatible with the original standard and can thus be implemented easily. The experimental results demonstrate that the proposed algorithm can reduce the number of checks by about 50%, thus significantly enhancing bandwidth.

Development of sandwich joining piece to fabricate segmented half-Heusler/skutterudite thermoelectric joints

Sn/Ni-Sn/Sn sandwich joining piece was developed and applied to fabricate segmented half-Heusler/skutterudite thermoelectric joints,and high-temperature service behavior of the joints was studied.The microstructure and contact resistance of the joint before and after aging were investigated.The joints are well bonded and no cracks appear at the interfaces of the joint before and after aging,which can be attributed to the formation of high-melting point intermetallic compounds.The electrical resistance crosses the joining layer smoothly and the contact resistance is low.These results show that the sandwich joining piece is effective and flexible,and promising for the preparation of segmented thermoelectric devices.

Development in the research of molecular mechanism of Alzheimer's disease

Alzheimer’s disease (AD) is a kind of central nervous system disease. The cause of AD is unclear. It is found that the remarkable histopathological characters of AD are senile plaques and neurofibrillary tangles.β-amyloid plays an important role in the formation of senile plaques and the abnormal phosphorylation of Tau protein is the main reason of neurofibrillary tangles. Apolipoprotein E is correlated to AD’s access, and the third pathological characterAMY plaque perhaps represents a new cause of AD. Presenlin and proteinaceous infectious particles are also related with AD. A summary of molecular mechanism for AD and the development of research is presented.

SPECIAL TOPICS: An important aspect of structural design of super-tall buildings and structures: Across-wind loads and effects

Across-wind loads and effects have become increasingly important factors in the structural design of super-tall buildings and structures with increasing height. Although researchers have investigated the problem for over 30 years, the research achievements of

Numerical investigation of the wind environment around tall buildings in a central business district

The wind environment around tall buildings in a central business district(CBD)was numerically investigated.The district covers an area of-^4.0 km2 and features a high density of tall buildings.In this study,only buildings taller than 20 m were considered,resulting in 173 tall buildings in the analysis.The numerical investigation was realized using the commercial computational fluid dynamics code FLUENT with the realizable A-6:turbulence model.Special efforts were made to maintain inflow boundary conditions throughout the computational domain.The reliability of the numerical method was validated using results from an experimental investigation conducted in the core area of the CBD(〜1.5 km2).Experimental and numerical investigations of wind speed ratios at the center of the three tallest buildings in the CBD agree within an uncertainty factor of 2.0.Both the experimental and numerical results show that wind speed ratios in the wind field with exposure category D are higher than those from the wind field with exposure category B.Based on the above validation work,the wind environment around tall buildings in the whole CBD was then investigated by numerical simulation.Common flow phenomena and patterns,such as stagnation points,shielding effects,separation flow,and channeling flow,were identified around the tall buildings.The pedestrianlevel wind environment around tall buildings in the CBD was further evaluated using nearby meteorological wind data.The evaluation results show that some pedestrian activities,such as sitting at the center of the three tallest buildings,are unadvisable when the wind blows from the south-east.

Safety Verification of Semi-Algebraic Dynamical Systems via Inductive Invariant

To verify the safety of nonlinear dynamical systems based on inductive invariants, key issues include defining the most complete inductive condition and discovering an inductive invariant that satisfies the specified inductive condition. In this paper, to lay a solid foundation for future research into the safety verification of semi- algebraic dynamical systems, we first establish a formal framework for evaluating the quality of continuous inductive conditions. In addition, we propose a new complete and computable inductive condition for verifying the safety of semi-algebraic dynamical systems. Compared with the existing complete and computable inductive condition, this new inductive condition can be easily adapted to achieve a set of sufficient inductive conditions with different level of conservativeness and computational complexity, which provides us with a means to trade off between the verification power and complexity. These inductive conditions can be solved by quantifier elimination and SMT solvers.