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Methane pyrolysis in preparation of pyrolytic carbon:Thermodynamic and kinetic analysis by density functional theory

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Chinese Journal of Aeronautics 2020年第3期33卷 1064-1073页

作者： Chunxia HU he shen Shouyang ZHANG hejun LI State Key Laboratory of Solidification Processing C/C Composites Research CenterNorthwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering California State UniversityLos AngelesCA 90032USA

The density functional theory has been successfully applied in analyzing pyrolytic carbon deposition by methane pyrolysis from the view of thermodynamics and kinetics based on a total number of 39 elementary reactions.M06-2X/def2-TZVP level was employed to optimize species structures and locate the transition *** enthalpy changes and Gibbs free energy changes of all the reactions in the temperature range of 298.15–1800K were derived with optimized *** show that the reacting temperature should be above 1200 K based on the equilibrium constant analysis,which is consistent with the typical reaction temperature adopted in *** energy surface profiles report that radical attacking reactions have lower energy barriers than those direct decomposition reactions,especially hydrogen radical attacking *** energy barriers of the first steps,dehydrogenations of methane and ethylene,are 272.4 kJ·mol^(-1)and 288.9 kJ·mol^(-1)at 1200 K,which are very close to the experimental activation energy for methane *** most favorable decomposition reaction path is the path of hydrogen radical attacking *** highest energy barrier of the path at 1200K is 185.7kJ·mol^(-1)presented by the C–H bond breaking in ethynyl attacked by hydrogen radical.

关键词： Density functional theory Kinetics Methane pyrolysis Pyrolytic carbon Thermodynamics

Determination of n+1 Gamete Transmission Rate of Trisomics and Location of Gene Controlling 2n Gamete Formation in Chinese Cabbage(Brassica rapa)

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Journal of Integrative Plant Biology 2009年第1期51卷 29-34页

作者： Cheng-he Zhang Xiao-Feng Li Shu-Xing shen he Yuan Shu-Xin Xuan College of Horticulture Agncultural University of Hebei Baoding 071001 China

A set of trisomics of Chinese cabbage was used for determining the n-I-1 gamete transmission rate and locating the gene controlling 2n gamete formation on the corresponding chromosome. The results showed that the transmission rates of extra chromosomes in different trisomics varied from 0% to 15.38% by male gametes and from 0% to 17.39% by female gametes. Of the nine F2 populations derived from the hybridizations between each trisomic and Bp058 （2n gamete material）, only Tri- 4xBp058 showed that the segregation ratio of plants without 2n gamete formation to plants with 2n gamete formation was 10.38：1, which fitted the expected segregation ratio of the trisomics （AAa） based on the 7.37% of n＋l gamete transmission through female and 5.88% through male. In other populations the segregation ratios varied from 2.48：1 to 3.72：1, which fitted the expected 3：1 segregation ratio of the bisomics （Aa）. These results suggested that the gene controlling 2n gamete formation in Chinese cabbage Bp058 was located on chromosome 4. Further trisomic analysis based on the chromosome segregation and the incomplete stochastic chromatid segregation indicated that the gene locus was tightly linked to the centromere.

关键词： Chinese cabbage gene location n+l gamete transmission primary trisomics 2n gametes.

Mechanism and monitoring and early warning technology for rockburst in coal mines

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International Journal of Minerals,Metallurgy and Materials 2021年第7期28卷 1097-1111页

作者： Xue-qiu he Chao Zhou Da-zhao Song Zhen-lei Li An-ye Cao shen-quan he Majid Khan School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mine University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Coal Resource and Mine Safety China University of Mining and TechnologyXuzhou 221116China

On the basis of the massive amount of published literature and the long-term practice of our research group in the field of prevention and control of rockburst,the research progress and shortcomings in understanding the rockburst phenomenon have been comprehensively *** study focuses on the occurrence mechanism and monitoring and early warning technology for rockburst in coal *** showed that the prevention and control of rockburst had made significant ***,with the increasing mining depth,several unre-solved concerns remain *** the in-depth research and analysis,it can be inferred that rockburst disasters involve three main problems,i.e.,the induction factors are complicated,the mechanism is still unclear,and the accuracy of the monitoring equipment and multi-source stereo monitoring technology is *** monitoring and warning standards of rockburst need to be further clarified and *** with the Internet of Things,cloud computing,and big data,a study of the trend of rockburst needs to be ***-more,the mechanism of multiphase and multi-field coupling induced by rockburst on a large scale needs to be explored.A multisystem and multiparameter integrated monitoring and early warning system and remote monitoring cloud platform for rockburst should be explored and ***-reliability sensing technology and equipment and perfect monitoring and early warning standards are considered to be the de-velopment direction of rockburst in the *** research will help experts and technicians adopt effective measures for controlling rock-burst disasters.

关键词： coal mine rockburst mechanism monitoring and early warning technology multiparameter

Microstructure characterization of a pressureless infiltrating oxidized SiCp preform by Al-8Mg

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International Journal of Minerals,Metallurgy and Materials 2011年第2期18卷 223-228页

作者： Shu-bin Ren Xiao-yu shen Xin-bo he Xuan-hui Qu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

The microstructure of a pressureless infiltrating 55vol% oxidized SiC preform by Al-8Mg alloy was characterized by transmission electron microscopy （TEM）, high resolution TEM （HRTEM）, field emission scanning electron microscopy （FE-SEM）, and X-ray diffraction. The TEM image of the interface between Al and SiC shows that the surface of SiC is covered by a rough nanocrystal layer of MgAl2O4, Al2O3, and Si, produced by the interfacial reaction of Al, Mg, and SiO2 on the surface of SiC. The Al-SiC interface is also examined by HRTEM to be better understood how MgAl2O4 and Al2O3 are produced. Dendritic Al2O3 crystals are embedded in the pores of the composite generated from the mutual bonding of SiO2 on the surface of SiC. Columnar AlN crystals of about 250 nm in length are bunched vertically on the SiC particle surface.

关键词： microstructure composites interfaces pressureless infiltration oxidation.

A Sensing Layer Network Resource Allocation Model Based on Trusted Groups

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China Communications 2019年第10期16卷 151-173页

作者： Bei Gong Xipeng Zhang shen he Nan Tian Yubo Wang Faculty of Information Technology Beijing University of TechnologyBeijing 100124China China Mobile Research Institute Beijing 100055China 91977 PLA(The People’s Liberation Army) Beijing 10000 China

There are many heterogeneous sensing nodes in the sensing layer of the Internet of Things, and the amount of data transmission is huge, which puts high requirements on the allocation of network bandwidth. At the same time, untrusted sensing nodes maliciously invade network resources. Therefore, how to confirm whether a sensing node is trusted and reasonably allocate network resources is an urgent problem to be solved. To resolve this issue, this paper proposes a sensing network resource allocation model based on trusted groups. Through the sensing node computing environment and behavior measurement, we can identify and exclude untrusted nodes, so the trusted group can be built. Then the network resources are distributed from a global perspective. Based on the available bandwidth of the link, a network resource fusion model of IPv4 and IPv6 is proposed. On this basis, a global network resource allocation model is further proposed. Afterwards, real-time monitoring of data transmission behavior ensures data security during transmission. Simulation experiments show that this mechanism can effectively optimize the bandwidth allocation in the data transmission process and has little effect on the running efficiency of existing network applications. At the same time, it can effectively guarantee the trust of nodes and achieve trusted data transmission.

关键词： internet of things trust measurement link bandwidth network resource allocation data transmission

Transplantation of adult spinal cord grafts into spinal cord transected rats improves their locomotor function

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Science China(Life Sciences) 2019年第6期62卷 725-733页

作者： he shen Xi Chen Xing Li Ke Jia Zhifeng Xiao Jianwu Dai Key Laboratory for Nano-Bio Interface Research Division of Nanobiomedicine Suzhou Institute of Nano-Tech and Nano-Bionics Chinese Academy of Sciences Suzhou 215123 China State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing 100101 China Shigatse Branch Xinqiao Hospital Army Medical University (Third Military Medical University) Shigatse 857000 China Key Laboratory of Organ Injury Aging and Regenerative Medicine of Hunan Province Xiangya Hospital Central South University Changsha 410008 China

Grafted embryonic central neural tissue pieces can recover function of hemisected spinal cord in neonatal rats and promote axonal growth in adults. However, spinal cord segments from adults have not been used as donor segments for allogeneic transplantation. here, we utilized adult spinal cord tissue grafts(aSCGs) as donor constructs for repairing complete spinal cord injury(SCI). Moreover, to provide a favourable microenvironment for SCI treatment, a growth factor cocktail containing three growth factors(brain-derived neurotrophic factor, neurotrophin-3 and vascular endothelial growth factor), was applied to the aSCG transplants. We found that the locomotor function was significantly improved 12 weeks after transplantation of aSCGs into the spinal cord lesion site in adult rats. Transplantation of aSCGs combined with these growth factors enhanced neuron and oligodendrocyte survival and functional restoration. These encouraging results indicate that treatment of complete SCI by transplanting aSCGs, especially in the presence of growth factors, has a positive effect on motor functional recovery, and therefore could be considered as a possible therapeutic strategy for SCI.

关键词： spinal cord injury (SCI) transplantation adult spinal cord grafts (aSCGs) function recovery adult host transection

A new maximum-likelihood phase estimation method for X-ray pulsar signals

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第6期15卷 458-469页

作者： Hua ZHANG Lu-ping XU Yang-he shen Rong JIAO Jing-rong SUN School of Aerospace Science and Technology Xidian University

X-ray pulsar navigation(XPNAV) is an attractive method for autonomous navigation of deep space in the future. Currently, techniques for estimating the phase of X-ray pulsar radiation involve the maximization of the general non-convex object functions based on the average profile from the epoch folding method. This results in the suppression of useful information and highly complex computation. In this paper, a new maximum likelihood(ML) phase estimation method that directly utilizes the measured time of arrivals(TOAs) is presented. The X-ray pulsar radiation will be treated as a cyclo-stationary process and the TOAs of the photons in a period will be redefined as a new process, whose probability distribution function is the normalized standard profile of the pulsar. We demonstrate that the new process is equivalent to the generally used Poisson model. Then, the phase estimation problem is recast as a cyclic shift parameter estimation under the ML estimation, and we also put forward a parallel ML estimation method to improve the ML solution. Numerical simulation results show that the estimator described here presents a higher precision and reduces the computational complexity compared with currently used estimators.

关键词： X-ray pulsar Poisson model Phase estimation Maximum likelihood

Seismites in the Dasheng Group： New evidence of strong tectonic and earthquake activities of the Tanlu Fault Zone

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Science China Earth Sciences 2016年第3期59卷 601-618页

作者： TIAN Hong Shui Antonius Johannes VAN LOON WANG Hua Lin ZHANG shen he ZHU Jie Wang School of Civil Engineering Shandong Jianzhu University Jinan 250101 China Geological Institute Adam Mickiewicz University Mak6w Polnych 16 61-606 Poznan Poland Earthquake Engineering Research Center of Shandong Province Jinan 250014 China

More than 80 layers of seismites were recognized from the Early Cretaceous Dasheng Group in the Mazhan and Tancheng graben basins in the Tanlu Fault Zone, eastern China. The responsible seismic events took place about 110–100 Ma in the Early Cretaceous. The fault zone was affected at the time by strong tectonics, due to tension-related stretching and scattered squeezing by strike-slip faults. These tectonic activities induced a series of strong earthquakes with Richter magnitudes(M) of 5–8.5. The earthquakes affected saturated or semi-consolidated flood and lake sediments, and produced intra-layer deformations by several processes, including liquefaction, thixotropy, drop, faulting, cracking, filling and folding, which resulted in the formation of various soft-sediment deformation structures, such as dikes and veins of liquefied sand, liquefied breccias, liquefied homogeneous layers, load structures, flame structures, ball-and-pillow structures, boudinage, diapirs, fissure infillings, a giant conglomerate wedge, and syn-sedimentary faults. The seismites are new evidence of tectonic and seismic activities in the Tanlu Fault Zone during the Early Cretaceous; the series of strong seismic events that can be deduced from them must be considered as a response to the destruction of the North China Craton.

关键词： Seismites Dasheng Group Early Cretaceous Seismic event Tanlu Fault Zone Craton destruction

Jiedu Sangen decoction inhibits chemoresistance to 5-fluorouracil of colorectal cancer cells by suppressing glycolysis via PI3K/AKT/HIF-1αsignaling pathway

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Chinese Journal of Natural Medicines 2021年第2期19卷 143-152页

作者： SUN Lei-Tao ZHANG Le-Yin SHAN Fei-Yu shen Min-he RUAN Shan-Ming Department of Medical Oncology The First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhou 310006China The First Clinical Medical College of Zhejiang Chinese Medical University Hangzhou 310053China Department of Traditional Chinese Medicine The First Affiliated Hospital of Wenzhou Medical UniversityWenzhou 325000China

Drug resistance is a major obstacle in the development of effective colorectal cancer(CRC)*** study aimed to explore the reversal abilities of Jiedu Sangen decoction(JSD)on the 5-fluorouracil(5-FU)resistance and its underlying molecular *** changes in HIF-1 of CRC tissues were firstly revealed by bioinformatics ***,cell viabilities of JSD and 5-FU treatments on 5-FU resistant human colon cancer cells(HCT-8/5-FU)were *** of phosphoinositide 3-kinase(PI3K),protein kinase B(AKT)/p-AKT,hypoxia-inducible factor 1(HIF-1α),as well as glycolysis related proteins such as L-lactate dehydrogenase A(LDHA),Glucose transporter type 1(Glut1),hexokinase 2(HKII),and cysteinyl aspartate specific proteinase(Caspase)family members in HCT-8/5-FU cells,HIF-1αsilenced HCT-8/5-FU cells and tumor tissues were detected by western ***-1αwas found over expressed in CRC tissues according to public available datasets in *** inhibition rates of HCT-8/5-FU cells were increased along with the increase of JSD *** caused down-regulated HIF-1α,PI3K,AKT/p-AKT,HKII and Glut1,as well as up-regulated Caspase3 and Caspase9 in HCT-8/5-FU cells and tumor *** HIF-1αsilenced HCT-8/5-FU cells,synergistic group showed significantly reduced expression levels of PI3K,AKT,***,up-regulated expressions of Caspase6 and Caspase7 were *** combined with 5-FU also exhibited obvious inhibitory efficiency on tumor growth in *** may reverse 5-FU resistance by suppressing glycolysis via PI3K/AKT/HIF-1αsignaling pathway,thereby inhibiting glycolysis and induce apoptosis to enhance anti-tumor activity.

关键词： Jiedu Sangen decoction 5-Fluorouracil resistance Glycolysis Apoptosis Colorectal cancer