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A fundamental study on the fluorescence-quenching effect of nitro groups in tetraphenylethene AIE dyes with electron-withdrawing groups

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Chinese Chemical Letters 2021年第6期32卷 1925-1928页

作者： Cheng-Xiao Zhao tian liu Manyi Xu Hao Lin Chong-Jing Zhang State Key Laboratory of Bioactive Substance and Functions of Natural Medicines and Beijing Key Laboratory of Active Substances Discovery and Drugability Evaluation Institute of Materia MedicaPeking Union Medical College and Chinese Academy of Medical SciencesBeijing 100050China School of Pharmaceutical Science Shanxi Medical UniversityTaiyuan 030001China

A nitro group is a common fluorescence quencher,but its quenching efficiency can be easily affected by the surrounding *** date,there has been no systematic study on the effects of electronwithdrawing groups on the quenching efficiency of nitro ***,by virtue of experimental validation and theoretical calculations,we found that strong electron-withdrawing groups,such as pyridinium and dicyanovinyl groups,are detrimental to the quenching effect of nitro *** the electron-withdrawing ability could restore the nitro group’s quenching effect.

关键词： Fluorescence Aggregation-induced emission Quenching effect Nitro group

Ensemble-based optimization of hydraulically fractured horizontal well placement in shale gas reservoir through Hough transform parameterization

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Petroleum Science 2021年第3期18卷 839-851页

作者： Liang Xue Shao-Hua Gu Xie-Er Jiang Yue-tian liu Chen Yang State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing 102249China Department of Oil-Gas Field Development Engineering College of Petroleum EngineeringChina University of Petroleum(Beijing)Beijing 102249China State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efective Development Beijing 100083China Sinopec Petroleum Exploration and Production Research Institute Beijing 100083China School of Water Conservancy North China University of Water Resources and Electric PowerZhengzhou 450046HenanChina

Shale gas reservoirs have been successfully developed due to the advancement of the horizontal well drilling and multistage hydraulic fracturing ***,the optimization design of the horizontal well drilling,hydraulic fracturing,and operational schedule is a challenging *** ensemble-based optimization method(EnOpt)is proposed here to optimize the design of the hydraulically fractured horizontal well in the shale gas *** objective is to maximize the net present value(NPV)which requires a simulation model to predict the cumulative shale gas *** accurately describe the geometry of the hydraulic fractures,the embedded discrete fracture modeling method(EDFM)is used to construct the shale gas simulation *** efects of gas absorption,Knudsen difusion,natural and hydraulic fractures,and gas-water two phase fow are considered in the shale gas production *** improve the parameter continuity and Gaussianity required by the EnOpt method,the Hough transformation parameterization is used to characterize the horizontal *** results show that the proposed method can efectively optimize the design parameters of the hydraulically fractured horizontal well,and the NPV can be improved greatly after optimization so that the design parameters can approach to their optimal values.

关键词： Shale gas Ensemble optimization Embedded discrete fracture model Hough transformation

Raising the production of phloretin by alleviation of by-product of chalcone synthase in the engineered yeast

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Science China(Life Sciences) 2020年第11期63卷 1734-1743页

作者： Chunmei Jiang Xiaonan liu Xianqing Chen Yi Cai Yibin Zhuang tian liu Xiaoxi Zhu Hui Wang Yuwan liu Huifeng Jiang Wen Wang Key Laboratory for Space Bioscience and Space Biotechnology School of Life SciencesNorthwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Systems Microbial Biotechnology Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin 300308China University of Chinese Academy of Sciences Beijing 100049China Center for Ecology and Environmental Sciences Northwestern Polytechnical UniversityXi’an 710072China Jiaxing Synbiolab Biotechnology Co. Ltd.Jiaxing 314006China

Phloretin is an important skin-lightening and depigmenting agent from the peel of apples. Although de novo production of phloretin has been realized in microbes using the natural pathway from plants, the efficiency of phloretin production is still not enough for industrial application. Here, we established an artificial pathway in the yeast to produce phloretin via assembling two genes of p-coumaroyl-CoA ligase(4CL) and chalcone synthase(CHS). CHS is a key enzyme which conventionally condenses a CoA-tethered starter with three molecules of malonyl-CoA to form the backbone of flavonoids. However, there was 33% of byproduct generated via CHS by condensing two molecules of malonyl-CoA during the fermentation process. Hence, we introduced a more efficient CHS and improved the supply of malonyl-CoA through two pathways;the by-product ratio was decreased from 33% to 17% and the production of phloretin was improved from 48 to 83.2 mg L^(-1). Finally, a fed-batch fermentation process was optimized and the production of phloretin reached 619.5 mg L^(-1), which was 14-fold higher than that of the previous studies. Our work established a platform for the biosynthesis of phloretin from the low-cost raw material 3-(4-hydroxyphenyl) propanoic acid and also illustrated the potential for industrial scale bio-manufacturing of phloretin.

关键词： phloretin Saccharomyces cerevisiae metabolic engineering microbial cell factories fed-batch fermentation

Low Power and High Sensitivity MOSFET-Based Pressure Sensor

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Chinese Physics Letters 2012年第8期29卷 276-278页

作者： ZHANG Zhao-Hua REN tian-Ling ZHANG Yan-Hong HAN Rui-Rui liu Li-tian Tsinghua National Laboratory for Information Science and Technology Institute of MicroelectronicsTsinghua UniversityBeijing 100084

Based on the metal-oxide-semiconductor field effect transistor(MOSFET)stress sensitive phenomenon,a low power MOSFET pressure sensor is *** with the traditional piezoresistive pressure sensor,the present pressure sensor displays high performances on sensitivity and power *** sensitivity of the MOSFET sensor is raised by 87%,meanwhile the power consumption is decreased by 20%.

关键词： power MOSFET transistor

Synthesis and Crystal Structure of a One-dimensional Azido-bridged Manganese (II) Compound [Mn(N_3)_2(H_2O)_3·C_6H_(12)N_4]_n

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Chinese Journal of Structural Chemistry 2006年第2期25卷 135-138页

作者： CHEN Hui WANG Wen-Guo ZHANG Xiao-Feng CHEN Chang-Neng liu Qiu-tian State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China

A new one-dimensional azido-bridged manganese compound has been prepared and structurally characterized by X-ray diffraction. The complex [Mn（N3）2（H2O）3·C6H12N4]n crystallizes in space group Pnma with a = 6.5252 （5）, b = 9.3226（7）, c = 22.2070（15） ,A°, V= 1350.89（17） ,A°^3, Z = 4, Mr = 333.24, Dc = 1.639 g/cm^3, μ = 1.005 mm^-1 and F（000） = 692. The final refinement gave R = 0.0328 and wR = 0.0777 for 1085 observed reflections with I 〉 2σ（I）. The structure contains [Mn（N3）2（H2O）3]n polymeric chains and uncoordinated hexamethylenetetramine （HMTA） molecules with Mn/HMTA molar ratio of 1：1. The Mn atoms are bridged by end-to-end azido ligands to construct one-dimensional zig-zag infinite chains. Each Mn atom is six-coordinated by three N atoms of three azido ligands and three water O atoms, resulting in an octahedral geometry. Extending hydrogenbonding interactions involving water O atoms, azido and HMTA N atoms link the chains and HMTA molecules into a three-dimensional network.

关键词： manganese crystal structure azide coordination polymer

Syntheses and Structures of Two Novel Salicylate-containing Mononuclear Manganese Complexes

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Chinese Journal of Structural Chemistry 2007年第8期26卷 920-923页

作者： WANG Hui-Sheng MA Cheng-Bing WANG Mei CHEN Chang-Neng liu Qiu-tian State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China

Two salicylate containing mononuclear manganese complexes formulated as [Mnand characterized by elemental analysis, IR and single-crystal X-ray diffraction analyses. Crystal data for compound 1： monoclinic, space group C2/c, a=30.748（6）, b=8.1933（13）, c=21.137（4） A, β=126.772（4）°, V=4265.5（13）A^3, Z=8, Mr=471.34, Dc=1.468 g/cm^3, μ=0.667 mm^-1, F（000）=1952,the final R=0.0637, wR=0.1783 （I 〉 2σ（I）） and GOOF=1.073; and those for compound 2： monoclinic,space group C2/c, a=14.505（5）, b=11.048（4）, c=20.711 （7）（A）, β=103.603（6）°, V=3225.6 （18）A^3, Z=4, Mr=668.65, Dc=1.377 g/cm^3, μ=0.466 mm^-1, F（000）=1416, the final R=0.0373, wR=0.1125 （I 〉2σ（I））, and GOOF=1.000. The Mn atoms of both complexes are six-coordinated in an axially elongated octahedral geometry for 1 and an axially compressed octahedral geometry for 2, and their oxidation states have been determined to be trivalent by bond valence sum calculation.

关键词： Mn(Ⅲ) salicylate crystal structure axially compressed octahedral geometry

Synthesis and Structure Characterization of a Tetranuclear Manganese(Ⅲ) Complex:[Mn_4O_2(O_2CMe)_6(MeOH)_2(dbm)_2]·2MeCOOH·2CH_2Cl_2

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Chinese Journal of Structural Chemistry 2007年第3期26卷 295-298页

作者： WANG Mei MA Cheng-Bing WANG Hui-Sheng CHEN Chang-Neng liu Qiu-tian State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China

The title compound, [Mn4O2（O2CMe）6（MeOH）2（dbm）2]·2MeCOOH·2CH2Cl2 （Hdbm = dibenzoylmethane）, has been synthesized and structurally determined by single-crystal X-ray diffraction. The crystal belongs to triclinic, space group P/, with a = 10.729（3）, b = 12.269（3）, c = 13.085（4） A, a = 106.367（3）,β = 107.643（2）, γ = 94.771（2）°, V = 1547.9（7） A^3, Z = 1, C50H64Cl4Mn4O24, Mr= 1410.57, Dc= 1.513 g/cm^3, F（000） = 724, Rint = 0.0147, T= 293（2） K and p = 1.046 mm ^-1. The final R = 0.0359 and wR = 0.0938 for 5791 observed reflections with 1 〉 2σ（/）. The structure of the complex consists of one [Mn4（μ3-O）2]^8＋ core with four coplanar Mn atoms disposed in an extended ＂butterfly-like＂ arrangement and two O atoms triply bridging each ＂wing＂, and the peripheral ligation is provided by six by-MeCO2^-, two terminal ,μ2-dbm- groups at the two ends of the molecule, and two MeOH molecules on the central Mn atoms, lntermolecular O…H-O hydrogen bonding interactions are found within the structure of the compound.

关键词： manganese crystal structure photosystem Ⅱ hydrogen bonding

DTAIS:Distributed trusted active identity resolution systems for the Industrial Internet

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Digital Communications and Networks 2024年第4期10卷 853-862页

作者： Tao Huang Renchao Xie Yuzheng Ren F.Richard Yu Zhuang Zou Lu Han Yunjie liu Demin Cheng Yinan Li tian liu State Key Lab.of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijingChina Department of Systems and Computer Eng. Carleton UniversityOttawaONCanada

In recent years,the Industrial Internet and Industry 4.0 came into *** the development of modern industrial intelligent manufacturing technology,digital twins,Web3 and many other digital entity applications are also *** applications apply architectures such as distributed learning,resource sharing,and arithmetic trading,which make high demands on identity authentication,asset authentication,resource addressing,and service ***,an efficient,secure,and trustworthy Industrial Internet identity resolution system is ***,most of the traditional identity resolution systems follow DNS architecture or tree structure,which has the risk of a single point of failure and DDoS *** they cannot guarantee the security and privacy of digital identity,personal assets,and device *** we consider a decentralized approach for identity management,identity authentication,and asset *** this paper,we propose a distributed trusted active identity resolution system based on the inter-planetary file system(IPFS)and non-fungible token(NFT),which can provide distributed identity resolution *** we have designed the system architecture,identity service process,load balancing strategy and smart contract *** addition,we use Jmeter to verify the performance of the system,and the results show that the system has good high concurrent performance and robustness.

关键词： Industrial Internet NFT IPFS Trust Identity resolution system

Serial Interval and Reproductive Number of COVID-19 Among 116 Infector-infectee Pairs—Jingzhou City,Hubei Province,China,2020

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China CDC weekly 2020年第27期2卷 491-495页

作者： tian liu Li Qi Menglei Yao Keqing tian Maowen Lin Hong Jiang Minmin Zeng Jigui Huang Department of Infectious Diseases Prevention and Control Jingzhou Center for Disease Control and PreventionJingzhou cityHubei ProvinceChina Chinese Field Epidemiology Training Program Chinese Center for Disease Control and PreventionBeijingChina Department of Infectious Diseases Prevention and Control Chongqing Municipal Center for Disease Control and PreventionChongqingChina State Key Laboratory of Infectious Disease Prevention and Control Collaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesNational Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijingChina

What is already known about this topic?The key epidemiological parameters including serial interval,basic reproductive number(R0),and effective reproductive number(Rt)are crucial for coronavirus disease 2019(COVID-19)control and *** studies provided different estimations but were often flawed by some limitations such as insufficient sample size and selection *** is added by this report?In this study,a total of 116 infector-infectee pairs meeting strict inclusion criteria were selected for *** mean serial interval of COVID-19 was 5.81 days(standard deviation:3.24).The estimated mean with 95%confidence interval of R0 was 3.39(3.07–3.75)and 2.98(2.62–3.38)using exponential growth(EG)and maximum likelihood(ML)methods,*** Rt in the early phase of the epidemic was above 1 with the peak of 4.43 occurring on January 8,and then showing subsequent declines and approaching 1 on January *** are the implications for public health practices?This study supports previous findings that COVID-19 has high transmissibility and that implementing comprehensive measures is effective in controlling the COVID-19 outbreak.

关键词： approaching limitations measures