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Studying the Fermi GeV light curve of Vela with the two-pole caustic model

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Research in Astronomy and Astrophysics 2009年第12期9卷 1324-1330页

作者： huan Yu Jun fang Ze-Jun Jiang Department of Physics Yunnan University Kunming 650091 China

An observation of the Vela pulsar with the Fermi Large Area Telescope has been recently reported and the GeV light curve shows two main peaks with a phase separation of ～0.43. We study the GeV light curve using the two-pole caustic model in which the peaks of the light curves of the pulsar result from caustic effects. The results show that the two-pole caustic model can reproduce the observed emission pattern of the two peaks and the bridge emission between them well, but overestimates the flux outside the two peaks. After taking account of the pair production effect on the azimuthal angle, we find that the resulting light curve is more consistent with the observation. We excluded the emissions from the field lines for which the distance from the null charge surface, where the pairs can be significantly produced, is larger than the radius of the light cylinder.

关键词： gamma rays: theory -- pulsars: individual (PSR B0833-45)

Expanding application of CRISPR-Cas9 system in microorganisms

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Synthetic and Systems Biotechnology 2020年第4期5卷 269-276页

作者： Jing Zhao huan fang Dawei Zhang Tianjin Institute of Industrial Biotechnology Chinese Academy of SciencesTianjin300308People's Republic of China Key Laboratory of Systems Microbial Biotechnology Chinese Academy of SciencesTianjin300308People's Republic of China University of Chinese Academy of Sciences Beijing100049People's Republic of China

The development of CRISPR-Cas9 based genetic manipulation tools represents a huge breakthrough in life sciences and has been stimulating research on metabolic engineering,synthetic biology,and systems *** CRISPR-Cas9 and its derivative tools are one of the best choices for precise genome editing,multiplexed genome editing,and reversible gene expression control in ***,challenges remain for applying CRISPR-Cas9 in novel microorganisms,especially those industrial microorganism hosts that are intractable using traditional genetic manipulation *** to further extend CRISPR-Cas9 to these microorganisms is being an urgent *** this review,we first introduce the mechanism and application of CRISPR-Cas9,then discuss how to optimize CRISPR-Cas9 as genome editing tools,including but not limited to how to reduce off-target effects and Cas9 related toxicity,and how to increase on-target efficiency by optimizing crRNA and sgRNA design.

关键词： CRISPR-Cas9 system Microorganisms Off-target Cas9 toxicity sgRNA

Hydrodynamic coefficients of a simplified floating system of gravity cage in waves

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第5期9卷 654-663页

作者： Chang-wen WU Fu-kun GUI Yu-cheng LI Wei-huan fang Marine Science School Zhejiang Ocean University Zhoushan 316000 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China College of Animal Sciences Zhejiang University Hangzhou 310058 China

Numerical simulation and experimental tests were carried out to examine the hydrodynamic behaviors of a double-column floating system of gravity cage under wave conditions. A floating system of gravity cage can be treated as a small-sized floating structure when compared with the wavelengths. The main problem in calculating the wave loads on the small-sized floating structure is to obtain the reasonable force coefficients, which may differ from a submerged structure. In this paper, the floating system of gravity cage is simplified to a 2D problem, where the floating system is set symmetrically under wave conditions. The motion equations were deduced under wave conditions and a specific method was proposed to resolve the problem of wave forces acting on a small-sized floating system of gravity cage at water surface. Results of the numerical method were compared with those from model tests and the hydrodynamic coefficients Cn and Cr were studied. It is found that Cn ranges from 0.6 to 1.0 while Cr is between 0.4 and 0.6 in this study. The results are useful for research on the hydrodynamic behavior of the deep-water gravity sea cages.

关键词： Gravity cage Floating system Hydrodynamic coefficients Waves

Phase transition and mechanical properties of Ni_(30)Cu_(20)Mn_(37+x)Ga_(13-x)(x=0–4.5) alloys

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Rare Metals 2014年第5期33卷 547-551页

作者： huan-fang Wang Jing-Min Wang Cheng-Bao Jiang Hui-Bin Xu School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics

Ni30Cu20Mn37＋xGa13-x（x = 0–4.5） alloys were studied with the phase transformation and mechanical properties. With the increase of Mn content, the martensitic transformation temperatures increase and the Curie temperature decreases. Simultaneously, the room temperature microstructure evolves from single phase of austenite to dual phases containing martensite and precipitation. Both the ductility and the strength of the polycrystalline alloys are significantly improved by the precipitation. Coupled magnetostructural transition from weak magnetic martensite to ferromagnetic austenite is obtained in both single-phase and ductile dual-phase alloys.

关键词： Ferromagnetic shape memory alloys(FSMAs) Martensitic transformation Magnetostructural transition Mechanical properties

Biostimulation-enhanced Biodegradation of Nitrobenzene in Contaminated Groundwater

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Chemical Research in Chinese Universities 2012年第5期28卷 818-823页

作者： AN Yong-lei ZHANG Lan-ying LIU Na ZHANG Lei GAO huan-fang Key Laboratory of Groundwater Resources and Environment Ministry of EducationJilin UniversityChangchun 130021P R.China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130012P.R.China

In this study, biostimulation technology was used for bioremediation of nitrobenzene-contaminated groundwater by adding a mixture of lactose and phosphate, peptone, and beef extract. During the process of biostimulation, the remediation effectiveness, microbial dehydrogenase activities and microbial densities were investigated; the varieties of microbial community structure and composition were analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis（PCR-DGGE） technique and the relative abundances of nitrobenzene-degrading gene（nbzA） were determined by fluorescence quantitative real-time PCR（RT-PCR）. Findings show that the removal rate of nitrobenzene in groundwater could reach about 60% by biostimulation with lactose and phosphate, 70% with peptone and 68% with beef extract. The microbial dehydrogenase activities and microbial densities were all improved obviously via biostimulation. The results of PCR-DGGE show that the microbial diversities were improved, and more than ten kinds of dominant microorganisms were detected after biostimulation. RT-PCR results show that the relative abundances of nbzA gene of microbes in groundwater were increased significantly, which indicated that biostimulation actually enhanced the growth of nitrobenzene-degrading bacteria. Therefore, biostimulation is a cost-effective and feasible bioremediation technique for nitrobenzene-contaminated groundwater.

关键词： Nitrobenzene Groundwater Biostimulation Polymerase chain reaction-denaturing gradient gel electro-phoresis(PCR-DGGE) Real-time polymerase chain reaction(RT-PCR)

Few-layer fbrmamidinium lead bromide nanoplatelets for ultrapuregreen and high-efficiency light-emitting diodes

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Nano Research 2019年第1期12卷 171-176页

作者： huan fang Wei Deng Xiujuan Zhang Xiuzhen Xu Meng Zhang Jiansheng Jie Xiaohong Zhang Institute of Functional Nano&Soft Materials(FUNSOM) Collaborative Innovation Center of Suzhou Nano Science and Technology(NANO-CIC)Jiangsu Key Laboratory for Carbon-Based Functional Materials&DevicesSoochow UniversitySuzhou 215123China

Formamidinium lead bromide perovskite(FAPbBr3)nanocrystals have attracted increasing attention due to their greener photoluminescence(PL)and higher thermal stability in comparison to more popular methylammonium lead bromide perovskite(MAPbBr3).Here we proposed a-facile and highly reproducible room-temperature method for the preparation of fewlayer(1-4)two-dimensional(2D)FAPbBr3 nanoplatelets(NPs)with ultrapure green PL at 532 nm and high photoluminescence quantum yield(PLQY)of 88%.High-efficiency ultrapure green light-emitting diodes(LEDs)based on the few-layer 2D FAPbBr3 NPs were further *** LEDs showed a maximum current efficiency(CE)of 15.31cd/A and an external quantum efficiency(EQE)of 3.53%,which are significantly better than the FAPbBr3 polycrystalline film-based LEDs reported so ***,the 2D FAPbBr3 NPs-based LEDs exhibited an ultrapure-green color emission that could cover 97%of the Recommendation 2020(Rec.2020)color standard and 114%of the national television system committee(NTSC)standard in the CIE 1931 color ***,the devices possessed a much better stability than the MAPbBr3 nanocrystals-based LEDs in air;the half lifetime T50 of our devices was about 5 times Ion ger than that of MAPbBr3 nan ocrystals-based *** work demonstrates the great potential of FAPbBr3 NPs in light-emitting devices for future ultrahigh-resolution displays.

关键词： formamidinium lead bromide perovskite few-layer nanoplatelets high-efficiency light-emitting diodes ultrapure-green electroluminescence

A survey on porcine circovirus type 2 infection and phylogenetic analysis of its ORF2 gene in Hangzhou,Zhejiang Province,China

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第2期9卷 148-153页

作者： Zong-zhao YANG Jiang-bing SHUAI Xian-jun DAI Wei-huan fang Institute of Preventive Veterinary Medicine Zhejiang University Hangzhou 310029 China Hangzhou Husbandry and Veterinary Station Hangzhou 310020 China College of Life Science China Jiliang University Hangzhou 310018 China

Porcine circovirus type 2 (PCV2) is closely related to the postweaning multisystemic wasting syndrome (PMWS). In this study, the pig serum and tissue samples collected from different regions of Hangzhou District in Zhejiang Province of China between 2003 and 2005 were analyzed by enzyme-linked immunosorbent assay (ELISA) for PCV2 antibody and by polymerase chain reaction (PCR) for ORF2 gene. The results show that out of 1250 randomly collected serum samples, 500 sera (40%) were seropositive for PCV2. PCR results demonstrate that Hangzhou PCV2 with more than 50% Chinese PCV2 strains and French PCV2 formed Cluster A. Only one PCV2 from Hangzhou belonged to Cluster B with some other Chinese PCV2 and Netherlands’s isolates. Cluster C consisted of PCV2 isolates from China, US, Canada, UK and Germany. The results indicate that the PCV2 infection was widespread in Hangzhou.

关键词： Porcine circovirus type 2 (PCV2) Seroprevalence ORF2 Phylogenetic analysis

A hybrid RNA-protein biosensor for high-throughput screening of adenosylcobalamin biosynthesis

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Synthetic and Systems Biotechnology 2024年第3期9卷 513-521页

作者： Xia Yang Huiying Wang Dongqin Ding huan fang Huina Dong Dawei Zhang College of Biological and Pharmaceutical Sciences China Three Gorges UniversityYichangHubei443002China Tianjin Institute of Industrial Biotechnology Chinese Academy of SciencesTianjin300308China Key Laboratory of Engineering Biology for Low-Carbon Manufacturing Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308China University of Chinese Academy of Sciences Beijing100049China

Genetically encoded circuits have been successfully utilized to assess and characterize target variants with desirable traits from large mutant *** is an essential coenzyme that is required in many intracellular physiological reactions and is widely used in the pharmaceutical and food ***-throughput screening techniques capable of detecting adenosylcobalamin productivity and selecting superior adenosylcobalamin biosynthesis strains are critical for the creation of an effective microbial cell factory for the production of adenosylcobalamin at an industrial *** this study,we developed an RNA-protein hybrid biosensor whose input part was an endogenous RNA riboswitch to specifically respond to adenosylcobalamin,the inverter part was an orthogonal transcriptional repressor to obtain signal inversion,and the output part was a fluorescent protein to be easily *** hybrid biosensor could specifically and positively correlate adenosylcobalamin concentrations to green fluorescent protein expression levels in *** study also improved the operating concentration and dynamic range of the hybrid biosensor by systematic *** individual cell harboring the hybrid biosensor presented over 20-fold higher fluorescence intensity than the negative ***,using such a biosensor combined with fluorescence-activated cell sorting,we established a high-throughput screening platform for screening adenosylcobalamin *** study demonstrates that this platform has significant potential to quickly isolate high-productive strains to meet industrial demand and that the framework is acceptable for various metabolites.

关键词： Adenosylcobalamin Genetically encoded biosensor Riboswitch Transcriptional repressor High-throughput screening

White-spot disease of Chinese soft-shelled turtles (Trionyx sinens) caused by Paecilomyces lilacinus

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第7期9卷 578-581页

作者： Xiao-liang LI Chu-long ZHANG Wei-huan fang Fu-cheng LIN Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine Institute of Preventive Veterinary Medicine Zhejiang University Hangzhou 310029 China Institute of Biotechnology Zhejiang University Hangzhou 310029 China

Chinese soft-shelled turtles （Trionyx sinens） in culture farms using an artificial warming system in Zhejiang, China, often show typical signs of white-spot disease such as white spots on their bodies, skin lesions, anorexia and eventually death. The sick turtles were mostly 5-80 g in weight. A suspected fungal pathogen was isolated from the sick turtles and verified as Paecilomyces lilacinus by sequence analysis of the internal transcribed spacer （ITS） of its ribosomal DNA （rDNA）. Detailed morphological examinations were also conducted to confirm the white-spot disease.

关键词： White-spot disease Chinese soft-shelled turtles Paecilomyces lilacinus Zhejiang