Photoconductive semiconductor switch-based triggering with 1 ns jitter for trigatron

Synchronization for multiple-pulse at nanosecond range shows a great value on the power multiplication and synchronous electric fieldsapplications. Nanosecond or sub-ns jitter synchronization is essential for the improved working efficiency of the large amounts of pulse modulesand accurate requirements for the power coherent combining applications. This paper presents a trigger generator based on a laser diodetriggered GaAs photoconductive semiconductor switch (PCSS) with low jitter and compact size characteristics. It avoids the high currentsthat are harmful to high-gain mode PCSSs. In the trigger circuit, a 200 pF capacitor is charged by a microsecond-scale 18 kV pulse and thendischarged via the high-gain mode GaAs PCSS to trigger the high-power trigatron switch. When triggered by the ~10 ns pulse generated by thePCSS, the DC-charged trigatron can operate in the 20e35 kV range with 10 ns rise time and 1 ns delay-time jitter.

Compact intense electron-beam accelerators based on high energy density liquid pulse forming lines

This paper provides a review of the compact intense electron-beam accelerators (IEBAs) based on liquid pulse forming lines (PFLs) that havebeen developed at the National University of Defense Technology (NUDT) in China. The history and roadmap of the compact IEBAs used todrive high-power microwave (HPM) devices at NUDT are reviewed. The properties of both de-ionized water and glycerin as energy storagemedia are presented. Research into the breakdown properties of liquid dielectrics and the desire to maximize energy storage have resulted in theinvention of several coaxial PFLs with different electromagnetic structures, which are detailed in this paper. These high energy density liquidPFLs have been used to increase the performance of IEBA subsystems, based on which the SPARK (Single Pulse Accelerator with spark gaps)and HEART (High Energy-density Accelerator with Repetitive Transformer) series of IEBAs were constructed. This paper also discusses howthese compact IEBAs have been used to drive typical HPM devices and concludes by summarizing the associated achievements and theconclusions that can be drawn from the results.

玉米盐诱导型启动子克隆及其植物表达载体构建

首先提取B73玉米(Zea mays)的基因组DNA,以此为模板利用PCR的方法克隆Zea mays salt-inducible protein kinase(STY2)基因上游1675 bp,将其命名为STY。从网站PlantCARE上的启动子预测工具在线对克隆到的启动子进行分析,结果表明:STY启动子中含有多种调控元件,典型的调控元件有:TATA-box,CAAT-box等等。另外还有2个盐诱导顺式作用元件GT1-motif和一些冷、干旱胁迫诱导有关的顺式作用元件,以及功能未知的元件。然后将克隆到的基因与植物双元表达载体pCAMBIA1301连接,并将其转入根癌农杆菌EHA105中,然后利用农杆菌介导法转化烟草,经过GUS组织化学染色验证STY的诱导功能。研究表明:STY启动子片段具有启动活性,为解决东北地区农业生产中严重的多元逆境胁迫问题开辟了有效途径。

Non-conjugated terpolymer acceptors for highly efficient and stable lager-area all-polymer solar cells

All-polymer solar cells(all-PSCs)have made significant progress recently,but few studies have been conducted to investigate the lab-to-manufacturing translation from the spin-coating method to the printing process.Here,the random copolymerization method and non-conjugated backbone approach are integrated to manipulate the morphology and photoelectric properties of the active layer for large-area printed all-PSCs.A series of non-conjugated terpolymer acceptors PYSe-TC_(6)T(x)(x=5,10,and 20,refers to the molar ratio of TC_(6)T unit)are developed by covalently introducing non-conjugated unit TC_(6)T into the PYSe host bipolymer by random copolymerization.The spin-coated PYSe-TC_(6)T(10)-based all-PSC demonstrates the best power conversion efficiency(PCE)of 13.54%,superior to the PYSe-based one(12.45%).More intriguingly,morphological studies reveal that a combination of the random polymerization and non-conjugated backbone strategy can effectively prevent the active layer from overaggregation and improve the film quality during the printing process,thereby minimizing the efficiency and technology gap between spin-coated small-area devices and blade-coated large-area devices.By directly using the same preparation condition of spin-coating,the blade-coated small-area(0.04 cm^(2))delivers a PCE of 12.83%and the large-area(1.21 cm^(2))device achieves a PCE of 11.96%with a small PCE loss.Both PCE value and PCE loss are one of the most outstanding performances of the bladecoated all-PSCs.These findings reveal that a combination of the non-conjugated flexible backbone with random copolymerization to develop non-conjugated terpolymers is an attractive design concept to smoothly realize the lab-to-manufacturing translation.

New Nanoplatform based on Upconversion Nanoparticles for Sensitive Detection of Acute promyelocytic Leukemia

Acute promyelocytic leukemia(APL)is a special leukemia accounting for above 10%of adult acute myeloid leukemia.The t(15;17)(q22;q21)is a specific chromosome reciprocal translocation of APL,resulting in the generation of a fusion gene between a retinoic acid receptor alpha(RARα)and promyelocytic leukemia(PML)at the molecular level.Many research demonstrate that PML/RARa fusion gene can be regarded as

Towards overcoming obstacles of type Ⅱ photodynamic therapy:Endogenous production of light,photosensitizer,and oxygen

Conventional photodynamic therapy(PDT)approaches face challenges including limited light penetration,low uptake of photosensitizers by tumors,and lack of oxygen in tumor microenvironments.One promising solution is to internally generate light,photosensitizers,and oxygen.This can be accomplished through endogenous production,such as using bioluminescence as an endogenous light source,synthesizing genetically encodable photosensitizers in situ,and modifying cells genetically to express catalase enzymes.Furthermore,these strategies have been reinforced by the recent rapid advancements in synthetic biology.In this review,we summarize and discuss the approaches to overcome PDT obstacles by means of endogenous production of excitation light,photosensitizers,and oxygen.We envision that as synthetic biology advances,genetically engineered cells could act as precise and targeted“living factories”to produce PDT components,leading to enhanced performance of PDT.

Recent progress of parameter-adjustable high-power photonic microwave generation based on wide-bandgap photoconductive semiconductors

Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ability.Over the past several years,benefitting from the sustainable innovations in laser technology and the significant progress in materials technology,megawatt-class output power electrical pulses with a flexible frequency in the P and L microwave wavebands have been achieved by photoconductive semiconductor devices.Here,we mainly summarize and review the recent progress of the high-power photonic microwave generation based on the SiC photoconductive semiconductor devices in the linear modulation mode,including the mechanism,system architecture,critical technology,and experimental demonstration of the proposed high-power photonic microwave sources.The outlooks and challenges for the future of multi-channel power synthesis development of higher power photonic microwave using wide bandgap photoconductors are also discussed.

生物多样性和环境因素对亚热带森林树木生物量和生物量生长的解耦影响

生物多样性与生态系统功能之间的关系已成为森林生态系统研究的核心问题。然而,在具有不同人类干扰历史的亚热带森林群落中,关于环境因子对生物多样性与生态系统功能关系影响的研究仍然较少。在本研究中,选择位于中国东部浙江省的34个亚热带森林样地,在考虑样方中的环境因子的基础上,利用线性模型,分析样地中木本植物多样性(物种、功能和谱系多样性)与样方内木本植物生物量或生物量变化量之间的关系。物种多样性和功能多样性,并非谱系多样性,与生物量和生物量的变化量之间存在显着相关性。生物量或生物量变化量与年平均温度和海拔高度之间存在显著的正相关关系。此外,在考虑环境因子和森林群落的演替阶段时,生物量变化量与功能多样性的关系显著强于生物量变化量与谱系多样性或物种多样性之间的关系。这些研究结果表明,生物多样性与生态系统功能之间的关系可能取决于生物多样性指数的选择和环境条件。

基于事件触发和网络攻击的负荷频率控制电力系统H_∞滤波器设计

本文研究了基于事件触发和网络攻击的负荷频率控制电力系统H_∞滤波器设计问题.为了节约网络传输带宽资源,本文引入事件触发机制降低负荷频率控制电力系统测量输出的传输量.考虑网络环境下随机网络攻击的影响,建立基于事件触发和网络攻击的负荷频率控制电力系统H_∞滤波误差模型.基于此滤波误差模型,利用Lyapunov稳定性理论和线性矩阵不等式技术分别给出了负荷频率控制电力系统均方渐近稳定的充分性条件和H_∞滤波器设计方法,最后通过仿真算例验证本文所提H_∞滤波器设计方法的有效性.

Isolation,Characterization,and Phylogenetic Analysis of Two New Crimean-Congo Hemorrhagic Fever Virus Strains from the Northern Region of Xinjiang Province,China

Crimean-Congo hemorrhagic fever(CCHF)caused by the CCHF virus(CCHFV)is a tick-borne natural focal disease with a mortality rate of approximately 50%.CCHFV is widely prevalent in Africa,southern Asia,the Middle East,and southeast Europe.CCHF outbreaks have been reported previously in Xinjiang province,China,especially in its southern region.Epidemiological surveys conducted on ticks and animals have revealed the presence of CCHFV strains in ticks,rodents,and infected individuals from cities and counties in southern Xinjiang.Phylogenetic analyses revealed that the Chinese CCHFV strains belong to one genotype,based on complete sequences of the S segments of its negative-stranded RNA genome.The present study reports two new CCHFV strains isolated from Hyalomma asiaticum asiaticum ticks collected from Fukang City and Wujiaqu City in the northern region of Xinjiang.Viral characteristics and their evolutionary relationships were analyzed through metagenomic and reverse-transcription PCR analyses;these analyses indicated that the genotype of both strains was different from that of other Chinese strains.Furthermore,previous reports of CCHFV in Xinjiang were reviewed and phylogenetic analyses were performed.CCHFV was found to prevail in Fukang City in Junggar Basin for more than 20 years,and that Fukang City and Wujiaqu City are considered natural reservoirs of different genotypes of CCHFV strains.Our findings facilitate the understanding of CCHFV distribution in Xinjiang province and provide insights into the evolutionary relationships among Chinese CCHFV strains.

Virus like particle-based vaccines against emerging infectious disease viruses

Emerging infectious diseases are major threats to human health.Most severe viral disease outbreaks occur in developing regions where health conditions are poor.With increased international travel and business,the possibility of eventually transmitting infectious viruses between different countries is increasing.The most effective approach in preventing viral diseases is vaccination.However,vaccines are not currently available for numerous viral diseases.Viruslike particles(VLPs) are engineered vaccine candidates that have been studied for decades.VLPs are constructed by viral protein expression in various expression systems that promote the selfassembly of proteins into structures resembling virus particles.VLPs have antigenicity similar to that of the native virus,but are non-infectious as they lack key viral genetic material.VLP vaccines have attracted considerable research interest because they offer several advantages over traditional vaccines.Studies have shown that VLP vaccines can stimulate both humoral and cellular immune responses,which may offer effective antiviral protection.Here we review recent developments with VLP-based vaccines for several highly virulent emerging or re-emerging infectious diseases.The infectious agents discussed include RNA viruses from different virus families,such as the Arenaviridae,Bunyaviridae,Caliciviridae,Coronaviridae,Filoviridae,Flaviviridae,Orthomyxoviridae,Paramyxoviridae,and Togaviridae families.

A new strain of Crimean-Congo hemorrhagic fever virus isolated from Xinjiang, China

Crimean-Congo hemorrhagic fever virus(CCHFV) is a highly pathogenic tick-borne virus with a fatality rate of up to 50% in humans. CCHFV is widely distributed in countries around the world.Outbreaks of CCHFV infection in humans have occurred in prior years in Xinjiang Province, China.Epidemiological surveys have detected CCHFV RNA in ticks and animals; however, few isolates were identified. In this study, we identified and isolated a new CCHFV strain from Hyalomma asiaticum asiaticum ticks collected from north of Tarim Basin in Xinjiang, China. A preliminary investigation of infection and antigens expression of CCHFV was performed in newborn mice. The target tissues for CCHFV replication in newborn mice were identified. The analysis of the phylogenetic relationships with other Chinese strains suggested that diverse genotypes of CCHFV have circulated in Xinjiang for years. These findings provide important insights into our understanding of CCHFV infection and evolution as well as disease prevention and control for local residents.

Characterization of two monoclonal antibodies, 38F10 and 44D11, against the major envelope fusion protein of Helicoverpa armigera nucleopolyhedrovirus

The envelope fusion protein F of baculoviruses is a class I viral fusion protein which play a significant role during virus entry into insect cells. F is initially synthesized as a precursor(F_0) and then cleaved into a disulfide-linked F_1 and F_2 subunits during the process of protein maturation and secretion. To facilitate further investigation into the structure and function of F protein during virus infection, monoclonal antibodies(mAbs) against the F_2 subunit of Helicoverpa armigera nucleopolyhedrovirus(HearNPV)(Ha F) were generated. Two kinds of mAbs were obtained according to their different recognition epitopes: one kind of mAbs, as represented by 38F10,recognizes amino acid(aa) 85 to 123 of F_2 and the other kind, represented by 44D11, recognizes aa148 to 173 of F_2. Western blot and immunofluorescence assay confirmed that both of the mAbs recognized the F protein expressed in HearNPV infected cells, however, only 44D11 could neutralize HearNPV infection. The results further showed that 44D11 may not interact with a receptor binding epitope, rather it was demonstrated to inhibit syncytium formation in cells expressing the Ha F protein. The results imply that the monoclonal antibody 44D11 recognizes a region within HaF_2 that may be involved in the F-mediated membrane fusion process.

Modeling and analyzing dynamics of malaria transmission with host immunity

In this paper,we investigate a compart mental model for malaria transmission,where the host individuals are distributed according to their immune status.The acquired immu nity of malaria is usually booted upon each exposure and gradually declines between the consecutive bouts of the disease.It is assumed that the recovered host individuals may be reinfected due to the immunity waning over time.The existence and stability of equilibria in the system,and the effect of the immunity status on dynamics of the system,are investigated,respectively.The phenomena of multiple endemic equilibria in our model are also observed.Our obtained results show that malaria may keep recurring under the first lower prevalence,however,when malaria is spreading in a population,it may remain at a different endemic level under suitable control strategies.

The asymmetric relationships of the distribution of conspecific saplings and adults in forest fragments

随着土地利用方式变化的加剧,生境片段化已成为影响植物多样性的主要因子之一。通常,当成年树个体的密度越高,其周边同种幼树个体的存活率可能会下降,从而为其它物种提供了空间和资源,进而可以维持较高的局域物种多样性。因此,同种成年树和幼树个体的空间分布格局关系和作用强度可以调节植物多样性。然而,对于在片段化森林中,同种成年树和幼树个体空间分布关系的研究却很少报道,迄今尚不清楚片段化景观中同种个体的空间分布关系与物种多样性之间的联系。本研究选择千岛湖陆桥岛屿系统中的27个岛屿,基于岛屿上幼树和成年树个体的空间分布数据,利用混合效应模型分析它们之间的作用强度。同种幼树和成年树个体的空间作用强度越大,说明它们之间的负相互作用越强,即幼树和成年树个体空间分布越分散。此外,本研究分析了岛屿属性(岛屿面积,与大陆的距离和与最近岛屿的距离)与同种个体空间作用强度及物种多样性之间的关系。结果表明,同种个体的空间作用强度随着与最近岛屿距离的增加而增加。同时,物种多样性随着同种个体的空间作用强度的增加而显著增加,且岛屿面积和同种个体的空间作用强度分别解释了岛屿间物种多样性差异的26%和6%,共同解释了8%。耐阴种和非常见种比非耐阴种和常见种的同种幼树和成年树的空间分布更为分散。本研究表明,同种个体的空间分布可能会影响多度较低物种在片段化森林中的生存,反映了生物相互作用对于维持片段化森林中的植物多样性具有重要作用。本研究也强调在检验同种密度制约时应考虑森林之间的连接度。

Assessment and prediction of the mechanical properties of ternary geopolymer concrete

This paper utilized granulated blast furnace slag(GBFS),fly ash(FA),and zeolite powder(ZP)as the binders of ternary geopolymer concrete(TGC)activated with sodium silicate solution.The effects of alkali content(AC)and alkaline activator modulus(AAM)on the compressive strength,flexural tensile strength and elastic modulus of TGC were tested and the SEM micrographs were investigated.The experimental results were then compared with the predictions based on models of mechanical properties,and the amended models of TGC were proposed taking account of the effects of AC and AAM.The results indicated that increasing AC and reducing AAM which were in the specific ranges(5%to 7%and 1.1 to 1.5,respectively)had positive effects on the mechanical properties of TGC.In addition,the flexural tensile strength of TGC was 27.7%higher than that of OPC at the same compressive strength,while the elastic modulus of TGC was 25.8%lower than that of OPC.Appropriate prediction models with the R2 of 0.945 and 0.987 for predicting flexural tensile strength and elastic modulus using compressive strength,respectively,were proposed.Fitting models,considering the effects of AC and AAM,were also proposed to predict the mechanical properties of TGC.

Fault-distribution-dependent reliable control for time-varying delay system

This paper considers the problem of reliable control for continuous-time systems with interval time-varying delay. By introducing a random matrix, a new practical actuator fault model is established. Using the Lyapunov-Krasovskii approach, a sufficient condition for the existence of reliable controller is expressed by a linear matrix inequality（LMI）. An illustrative example is exploited to show the effectiveness, of the proposed design procedures.