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17篇 您的检索式:作者名="ZHENG KEREN"
    题名 作者 年代 出处 被引量
1Seismogenesis and occurrence of earthquakes as observed by temporally continuous gravity variations in China显示文摘In the last decade and a half, a number of earthquakes of magnitude 4-5 have occurred in the Beijing_Tianjin_Tangshan_Zhangjiakou (BTTZ) region. On the basis of the analysis of the temporally continuous gravity variation data principally from the Baijiatuan (BJTN) semi_permanent gravity base station, a general picture of gravity variation related to the seismogenesis and occurrence of earthquakes has emerged.\;As gravity variation is generally observed on the earth’s surface, the predominant influence is that of the near_surface groundwater. The subsurface fluids are distributed throughout all depths in the crust and respond to the seismogenic processes of earthquakes as well. The influence of the subsurface fluid on gravity variation is, therefore, of equal importance. The fluids, which include the near_surface groundwater and the subsurface fluids distributed throughout all depths in the crust, play a more important role in the gravity variations in terms of the seismogenesis and occurrence of earthquakes than previously realized.\;The abundance of accumulated data shows that the dilatancy instability (IPE) model seems not applicable at least to the seismogenesis and occurrence of earthquakes in the BTTZ region. In order to reflect the physical reality, the earlier proposed combined dilatancy model requires modification. The seismogenic area in the BTTZ region may be modelled as a large pre_stressed volume of a fluid_filled poroelastic medium, including not only the pre_stressed volume surrounding the impending rupture zone but also the volume containing the rupture of the fault zone itself. The pre_stressed volume outside the impending rupture zone is under a state of relatively small change of the pre_existing regional tectonic stress, while the volume containing the impending rupture zone is an induced region of very high local stress concentration, and/or pore over_pressure.\;The calculated gravity variations based on the modified combined dilatancy model (MCDM) with the known physical parameters of the region resemble the observed residual gravity variations. Apparently the residual gravity variations, in addition to responding to the deep_seated seismogenesis and occurrence of earthquakes, predominantly respond to the near_surface groundwater, and the subsurface fluids, which themselves also respond to the seismogenesis and occurrence of earthquakes. On the basis of comparison between the calculated MCDM gravity variations and the observed residual gravity variations, the change of the regional tectonic stress field for the earthquakes of magnitude 4-5 in the BTTZ region could be approximately estimated to be in the neighbourhood of 5%-7%.\;It is apparent that simultaneously monitoring the temporally continuous variations of the near_surface groundwater, subsurface fluids, and gravity coupled with modelling would provide vital information on the history and evolution of the seismogenic processes about 10 months to 1 year prior to the occurrence of an earthquake of magnitude 4-5 and tens of years prior to that of an earthquake of magnitude 7-8 such as the Haicheng earthquake in 1975 and the Tangshan earthquake in 1976 in the BTTZ region. These earthquakes of magnitude 4-5, which so far have occurred in the BTTZ region, may well be the precursory events to a larger earthquake.Gongxu Gu John T. Kuo Keren Liu Jinhan Zheng Hongyan Lu Duanfa Liu 1998Chinese Science Bulletin1998,43,1:10
2Generation and characterization of stable pig pregastrulation epiblast stem cell lines显示文摘Pig epiblast-derived pluripotent stem cells are considered to have great potential and broad prospects for human therapeutic model developme nt and livestock breeding.Despite on going attempts since the 1990s,no stably defined pig epiblast-derived stem cell line has bee n established.Here,guided by in sights from a large-scale sin gle-cell tran scriptome an alysis of pig embryos from embryonic day(E)0 to E14,specifically,the tracing of pluripotency changes during epiblast development,we developed an in vitro culture medium for establishing and maintaining stable pluripotent stem cell lines from pig E10 pregastrulation epiblasts(pgEpiSCs).Enabled by chemical inhibition of WNT-related signaling in combination with growth factors in the FGF/ERK,JAK/STAT3,and Activin/Nodal pathways,pgEpiSCs maintain their pluripotency transcriptome features,similar to those of E10 epiblast cells,and normal karyotypes after more than 240 passages and have the potential to differentiate into three germ layers.Strikingly,ultradeep in situ Hi-C analysis revealed functional impacts of chromatin 3D-spatial associations on the transcriptional regulation of pluripote ncy marker genes in pgEpiSCs.I n practice,we con firmed that pgEpiSCs readily tolerate at least three rounds of successive gene editi ng and gene rated cloned gen e-edited live piglets.Our findings deliver on the long-a nticipated promise of pig pluripote nt stem cells and open new avenues for biological research,animal husbandry,and regenerative biomedicine.Minglei Zhi Jinying Zhang Qianzi Tang Dawei Yu Shuai Gao Dengfeng Gao Pengliang Liu Jianxiong Guo Tang Hai Jie Gao Suying Cao Zimo Zhao Chongyang Li Xiaogang Weng Mengnan He Tianzhi Chen Yingjie Wang Keren Long Deling Jiao Guanglei Li Jiaman Zhang Yan Liu Yu Lin Daxin Pang Qianqian Zhu Naixin Chen Jingjing Huang Xinze Chen Yixuan Yao Jingcang Yang Zicong Xie Xianya Huang Mengxin Liu Ran Zhang Qiuyan Li Yiliang Miao Jianhui Tian Xingxu Huang Hongsheng Ouyang Bofeng Liu Wei Xie Qi Zhou Zhonghua Liu Caihong Zheng Mingzhou Li Jianyong Han 2022Cell Research2022,32,4:3
3Evaluation of Surface Cracks Using Magnetic Flux LeakageTesting显示文摘The magnetic field distribution characteristics of surface cracks with various widths are discussed based on finite element (FEM) results. The crack depth was 0.20 mm, the width range was from 0.02 to 1.00 mm. The results showed that crack width and lift-off (the distance between surface and sensor) will influence signals. Discussed in this paper is the influence of various lift-off parameters on the peak to peak values of the normal component in magnetic flux leakage testing. The effects can be applied to evaluate surface breaking cracks of different widths and depths.An idea is presented to smooth narrow, sharp crack tips using alternating current (AC) field magnetization.Luming LI, Songling HUANG, Peng ZHENG and Keren SHINUT Center, Mechanical Engineering Department, Tsinghua University, Beijing 100084, China 2002Journal of Materials Science & Technology2002,18,4:3
4A review on the use of waste glasses in the production of cement and concrete显示文摘SHI Caijun ZHENG Keren 2007Resources Conservation and Recycling2007,52,2:1
5A review on the use of waste glasses in the production of cement and concrete显示文摘SHI CAIJUN ZHENG KEREN 2007Resources Conservation and Recycling2007,52,2:1
6A review on the use of waste glasses in the production of cement and concrete显示文摘SHI Caijun ZHENG Keren 2007Resources Conservation and Recycling2007,52,2:1
7A review on the use of waste glasses in the production of cement and concrete 显示文摘SHI Caijun ZHENG Keren 2007Resources Conservation and Recycling2007,52,:1
8A Review on the Use of Waste Glasses in the Production of Cement and Concrete显示文摘Shi Caijun Zheng Keren 2007Re- sources Conservation and Recycling2007,52,:1
9A review on the use of waste glasses in the production of cement and concrete resources 显示文摘SHI Caijua ZHENG Keren 2007Conservation and Recycling2007,52,2:1
10Discharge voltage behavior of electric double-layer capacitors during high-g impact and their application to autonomously sensing high-g accelerometers显示文摘在这研究,电的双层电容器(EDLC ) 的分泌物电压行为理论上并且试验性地在 high-g 影响期间被学习。微规模的动态机制被建议在 high-g 影响期间描述分泌物电压的增加的物理基础。基于这动态机制,一个多地模型被建立,并且模拟和分泌物电压增加现象的试验性的研究被进行。从模拟和试验性的数据,在增加的电压和 high-g 加速之间的关系被揭示。一个加速察觉范围多达, 10,000g 被验证。设备的设计被学习参数的影响优化,例如电极厚度和分泌物电流,在产量上。这个工作基于精力存储设备为自治传感器系统的开发开创新大街并且为许多实际应用程序例如是重要的在测试的碰撞和汽车安全。Keren Dai Xiaofeng Wang Fang Yi Yajiang Yin Cheng Jiang Simiao Niu Qingyu Li Zheng You 2018Nano Research2018,11,2:1
11A review on the use of waste glass in the production of cement and concrete显示文摘SHI Caijun ZHENG Keren 2005Resources Conservation and Recycling2005,2,2:1
12A review on the use of waste glass in the production of cement and concrete显示文摘SHI Caijun ZHENG Keren 2007Resources Conservation and Recycling2007,52,:1
13Quantum state and process tomography via adaptive measurements显示文摘We investigate quantum state tomography(QST) for pure states and quantum process tomography(QPT) for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert space, we first propose an adaptive protocol where only 2d. 1 measurement outcomes are used to accomplish the QST for all pure states. This idea is then extended to study QPT for unitary channels, where an adaptive unitary process tomography(AUPT) protocol of d2+d.1measurement outcomes is constructed for any unitary channel. We experimentally implement the AUPT protocol in a 2-qubit nuclear magnetic resonance system. We examine the performance of the AUPT protocol when applied to Hadamard gate, T gate(/8 phase gate), and controlled-NOT gate,respectively, as these gates form the universal gate set for quantum information processing purpose. As a comparison, standard QPT is also implemented for each gate. Our experimental results show that the AUPT protocol that reconstructing unitary channels via adaptive measurements significantly reduce the number of experiments required by standard QPT without considerable loss of fidelity.HengYan Wang WenQiang Zheng NengKun Yu KeRen Li DaWei Lu Tao Xin Carson Li ZhengFeng Ji David Kribs Bei Zeng XinHua Peng JiangFeng Du 2016Science China(Physics,Mechanics & Astronomy)2016,59,10:0
14Single-base resolution mapping of 2′-O-methylation sites by an exoribonuclease-enriched chemical method显示文摘2′-O-methylation(Nm)is one of the most abundant RNA epigenetic modifications and plays a vital role in the post-transcriptional regulation of gene expression.Current Nm mapping approaches are normally limited to highly abundant RNAs and have significant technical hurdles in m RNAs or relatively rare non-coding RNAs(nc RNAs).Here,we developed a new method for enriching Nm sites by using RNA exoribonuclease and periodate oxidation reactivity to eliminate 2′-hydroxylated(2′-OH)nucleosides,coupled with sequencing(Nm-REP-seq).We revealed several novel classes of Nm-containing nc RNAs as well as m RNAs in humans,mice,and drosophila.We found that some novel Nm sites are present at fixed positions in different t RNAs and are potential substrates of fibrillarin(FBL)methyltransferase mediated by sno RNAs.Importantly,we discovered,for the first time,that Nm located at the 3′-end of various types of nc RNAs and fragments derived from them.Our approach precisely redefines the genome-wide distribution of Nm and provides new technologies for functional studies of Nm-mediated gene regulation.Ping Zhang Junhong Huang Wujian Zheng Lifan Chen Shurong Liu Anrui Liu Jiayi Ye Jie Zhou Zhirong Chen Qiaojuan Huang Shun Liu Keren Zhou Lianghu Qu Bin Li Jianhua Yang 2023Science China(Life Sciences)2023,66,4:0
15Generalized modeling and experimental research on the transient response of supercapacitors under compressive mechanical loads显示文摘Supercapacitors(SCs)have been successfully used in electric vehicles or military equipment systems for their high power density.However,the mechanical impacts from vehicle crashes and missile penetration probably cause performance fluctuations or failure of SCs,which may threaten the safety of systems using SCs.In this paper,a generalized circuit model to analyze the transient process of SCs under mechanical loads is proposed.The circuit model simultaneously takes capacitance change,internal short-circuit and resistance change into account,an extra resistor-capacitor circuit(RCC)is added to simulate the nonlinear behavior during charging and discharging.Subsequently,the relationships between pressure and fundamental circuit parameters are determined by static methods.By taking the static test data into the circuit model,the transient response of different types of SCs under particular mechanical loading conditions is predicted.Finally,the influences of some crucial parameters on the voltage responses of SCs are revealed based on the simulations,which provide references for designing and optimizing mechanical load-resistant or self-sensing SCs in specific application scenarios.Jue Huang Keren Dai Yajiang Yin Zhaorong Chen Xiaofeng Wang Zheng You 2023Nano Research2023,16,5:0
16Simulation and structure optimization of triboelectric nanogenerators considering the effects of parasitic capacitance显示文摘寄生电容是在电的电路存在的一个不可避免、通常讨厌的电容,并且它是最重要的秒顺序当设计摩擦电 nanogenerator (TENG ) 时,因为它的大小比得上 TENG 电容的大小,必须被考虑的非理想的效果。这份报纸通过当模特儿和模拟调查结构和 TENG 的表演优化,考虑寄生电容。寄生电容通常被发现在匹配 TENG 的抵抗,最大的输出力量,和结构的 figures-of-merit (FOM ) 的最佳上在 TENG,和它的效果引起严重性能降级彻底地被调查并且讨论。象差距和电极长度那样的重要结构的参数的最佳值为 TENG 的不同工作模式被决定,系统地表明怎么这些结构的参数作为寄生电容的函数改变的最佳。另外,寄生电容能改进金属的高度忍耐,这被表明独立模式的 TENG。这个工作为实际应用为结构和 TENG 的表演优化提供一个理论基础并且支持机械收获精力的技术的发展。Keren Dai Xiaofeng Wang Simiao Niu Fang Yi Yajiang Yin Long Chen Yue Zhang Zheng You 2017Nano Research2017,10,1:0
17RNA m^(6)A reader YTHDF2 facilitates precursor miR-126 maturation to promote acute myeloid leukemia progression显示文摘As the most common internal modification of mRNA,Ne-methyladenosine(m^(6)A)and its regulators modulate gene expression and play critical roles in various biological and patholog-ical processes including tumorigenesis.It was reported previously that m^(6)A methyltransferase(writer),methyltransferase-like 3(METTL3)adds m^(6)A in primary microRNAs(pri-miRNAs)and fa-cilitates its processing into precursor miRNAs(pre-miRNAs).However,it is unknown whether m^(6)A modification also plays a role in the maturation process of pre-miRNAs and(if so)whether such a function contributes to tumorigenesis.Here,we found that YTHDF2 is aberrantly overexpressed in acute myeloid leukemia(AML)patients,especially in relapsed patients,and plays an onco-genic role in AML.Moreover,YTHDF2 promotes expression of miR-126-3p(also known as miR-126,as it is the main product of precursor miR-126(pre-miR-126)),a miRNA that was reported as an oncomiRNA in AML,through facilitating the processing of pre-miR-126 into mature miR-126.Mechanistically,YTHDF2 recognizes m^(6)A modification in pre-miR-126 and recruits AGO2,a regulator of pre-miRNA processing,to promote the maturation of pre-miR-126.YTHDF2 posi-tively and negatively correlates with miR-126 and miR-126's downstream target genes,respec-tively,in AML patients,and forced expression of miR-126 could largely rescue YTHDF2/Ythdf2 depletion-mediated suppression on AML cell growth/proliferation and leukemogenesis,indi-cating that miR-126 is a functionally important target of YTHDF2 in AML.Overall,our studies not only reveal a previously unappreciated YTHDF2/miR-126 axis in AML and highlight the ther-apeutic potential of targeting this axis for AML treatment,but also suggest that m^(6)A plays a role in pre-miRNA processing that contributes to tumorigenesis.Zheng Zhang Keren Zhou Li Han Andrew Small Jianhuang Xue Huilin Huang Hengyou Weng Rui Su Brandon Tan Chao Shen Wei Li Zhicong Zhao Ying Qing Xi Qin Kitty Wang Keith Leung Mark Boldin Chun-Wei Chen David Ann Zhijian Qian Xiaolan Deng Jianjun Chen Zhenhua Chen 2024Genes & Diseases2024,11,1:0
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