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NANO RESEARCH 2024年第12期17卷 10649-10654页

作者： Cheng, Lin Hu, Rongrong Jiang, Meizhen men, yumeng Wang, Yang Li, Jinlei Jia, Tianqing Sun, Zhenrong Feng, Donghai East China Normal Univ State Key Lab Precis Spect Shanghai 200241 Peoples R China Shanghai Inst Technol Coll Sci Shanghai 201418 Peoples R China Shanxi Univ Collaborat Innovat Ctr Extreme Opt Taiyuan 030006 Peoples R China

The formation and evolution dynamics of charge separation (CS) in a complex of CsPbBr3 quantum dots (QDs) and 1,4-benzoquinone (BQ) molecules are measured with a high-sensitive pump-orientation-probe technique by which spin signals of the CS state are monitored. An extraordinarily long-lasting CS is observed, with a characteristic time being up to a dozen days under ambient conditions, due to electron transferring from QDs to BQ molecules. Upon the long-lived CS, spin coherences of both electrons and holes are detected at room temperature, with a spin dephasing time of 420 and 26 ps, respectively. The long-lived CS and spin coherence have important implications for applications of perovskite nanomaterials in photocatalysis, photovoltaics, and spintronics.

关键词： charge separation perovskite quantum dots CsPbBr3 spin coherence pump-orientation-probe time-resolved ellipticity

Effect of Nb–V microalloying on the hot deformation behavior of medium Mn steels

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International Journal of Minerals,Metallurgy and Materials 2025年第02期 360-368页

作者： yumeng Wang Qinyi Guo Bin Hu Haiwen Luo School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The influence of Nb–V microalloying on the hot deformation behavior and microstructures of medium Mn steel(MMS) was investigated by uniaxial hot compression tests. By establishing the constitutive equations for simulating the measured flow curves, we successfully constructed deformation activation energy(Q) maps and processing maps for identifying the region of flow instability. We concluded the following consequences of Nb–V alloying for MMS.(i) The critical strain increases and the increment diminishes with the increasing deformation temperature, suggesting that NbC precipitates more efficiently retard dynamic recrystallization(DRX) in MMS compared with solute Nb.(ii) The deformation activation energy of MMS is significantly increased and even higher than that of some reported high Mn steels, suggesting that its ability to retard DRX is greater than that of the high Mn content.(iii) The hot workability of MMS is improved by narrowing the hot processing window for the unstable flow stress, in which fine recrystallized and coarse unrecrystallized grains are present.

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VR helicity density and its application in turbomachinery tip leakage flows

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Chinese Journal of Aeronautics 2022年第11期35卷 1-17页

作者： yumeng TANG Yangwei LIU School of Energyand Power Engineering Beihang UniversityBeijing 100083China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBejing 100083China State Key Laboratory of Aerodynamics China Aerodynamics Research and Development CenterMianyang 621000China

Helicity is an important quantity that represents the topological interpretation of vortices;however,helicity is not a Galilean *** this study,VR helicity density(HVR)is derived via taking the dot product of vorticity with the unit real eigen vector of the velocity gradient tensor when the complex eigenvalues *** analytical solution of HVR is derived to resolve it in a local pointwise manner,and the Galilean invariance of HVR is *** leakage flow structures in a direct numerical simulation of a tip leakage flow model and a delayed detached eddy simulation of a low-speed large-scale axial compressor rotor are extracted using helicity,eigen helicity density and HVR *** show that the utilization of HVR permits the identification and accentuation of concentrated *** identified by HVR appear in more connective *** in the case of helicity,the sign of HVR distinguishes between primary and secondary vortices,while eigen helicity density *** normalized HVR is superior to the normalized helicity density in locating the vortex axis,especially for the induced vortex ***,HVR is a strong candidate to replace the helicity density,especially when Galilean invariance is required.

关键词： Compressor Flow visualization Helicity Tip leakage flow Vortex identification Vortical flow

基于孟德尔随机化探讨肠道菌群与失眠的因果关联研究

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中国全科医学 2025年第8期28卷 954-961页

作者：郭玉梦崔杨霖张宪忠山东中医药大学山东省日照市中医医院中医经典科

背景随着失眠的发病率逐渐升高，其严重影响患者的精神及工作状态。肠道菌群被认为是失眠的一个危险因素，但目前存在相关证据较为缺乏的问题，难以准确认识二者之间的关系。目的使用两样本孟德尔随机化作为研究方法，探索肠道菌群与... 详细信息

背景随着失眠的发病率逐渐升高，其严重影响患者的精神及工作状态。肠道菌群被认为是失眠的一个危险因素，但目前存在相关证据较为缺乏的问题，难以准确认识二者之间的关系。目的使用两样本孟德尔随机化作为研究方法，探索肠道菌群与失眠之间的因果关系。方法使用MiBioGen联盟进行的最大可用全基因组关联研究荟萃分析（n=18 340）中肠道菌群的汇总统计数据，根据预设的阈值提取与196种肠道微生物相对丰度显著相关的单核苷酸多态性（SNPs）作为工具变量（IVs）。失眠的汇总统计数据来自英国生物样本库（UK Biobank）(n=462 341)。采用逆方差加权法（IVW）、MR-Egger回归、加权中位数法（WME）、加权众数法（WM）等检测肠道菌群与失眠之间的因果关系，其中以IVW法为主，根据效应指标优势比（OR）和95%置信区间（CI）评估结果。结合敏感性分析、异质性检验、基因多效性检验和异常值检验（MR-PRESSO）等方法来验证结果的稳定性和可靠性。并对发现与失眠有因果关系的菌群进行反向孟德尔随机化分析。结果 IVW结果显示蔷薇菌属(OR=0.787,95%CI=0.671～0.923,PFDR=0.016)、丹毒杆菌属(OR=0.880,95%CI=0.794～0.976,PFDR=0.077)、副普雷沃菌属(OR=0.891,95%CI=0.801～0.991,PFDR=0.083)、瘤胃球菌属UCG014组(OR=0.818,95%CI=0.697～0.961,PFDR=0.072)、巴斯德菌科(OR=0.897,95%CI=0.814～0.988,PFDR=0.081)、巴斯德菌目(OR=0.897,95%CI=0.814～0.988,PFDR=0.094)和失眠有关，未发现IVs存在基因多效性或显著异质性。根据反向孟德尔随机化分析结果，失眠对肠道菌群无显著的因果影响。结论蔷薇菌属、丹毒杆菌属、副普雷沃菌属、瘤胃球菌属UCG014组、巴斯德菌科、巴斯德菌目6种肠道菌群丰度与失眠的发病风险呈负相关，即丰度降低会增加失眠的发病风险，为失眠的保护因素。

关键词：肠道菌群失眠孟德尔随机化因果关联

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Energy-efficient resource management for CCFD massive MIMO systems in 6G networks

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Journal of Systems Engineering and Electronics 2022年第4期33卷 877-886页

作者： SU yumeng GAO Hongyuan ZHANG Shibo College of Information and Communication Engineering Harbin Engineering UniversityHarbin 150001China

This paper presents a co-time co-frequency fullduplex(CCFD)massive multiple-input multiple-output(MIMO)system to meet high spectrum efficiency requirements for beyond the fifth-generation(5G)and the forthcoming the sixth-generation(6G)*** achieve equilibrium of energy consumption,system resource utilization,and overall transmission capacity,an energy-efficient resource management strategy concerning power allocation and antenna selection is designed.A continuous quantum-inspired termite colony optimization(CQTCO)algorithm is proposed as a solution to the resource management considering the communication reliability while promoting energy conservation for the CCFD massive MIMO *** effectiveness of CQTCO compared with other algorithms is evaluated through *** results reveal that the proposed resource management scheme under CQTCO can obtain a superior performance in different communication scenarios,which can be considered as an eco-friendly solution for promoting reliable and efficient communication in future wireless networks.

关键词： the sixth-generation(6G) massive multiple-input multiple-output(MIMO) co-time co-frequency full-duplex energy-efficient resource management

PD-1/PD-L1 blockade in cervical cancer: current studies and perspectives

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Frontiers of Medicine 2019年第4期13卷 438-450页

作者： yumeng Wang Guiling Li Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases Fudan University Shanghai 200011 China Department of Integration of Western and Traditional Medicine Obstetrics and Gynecology Hospital of Fudan University Shanghai 200011 China

Cervical cancer (CC) is the fourth most commonly diagnosed female malignancy and a leading cause of cancer-related mortality worldwide, especially in developing countries. Despite the use of advanced screening and preventive vaccines, more than half of all CC cases are diagnosed at advanced stages, when therapeutic options are extremely limited and side effects are severe. Given these circumstances, new and effective treatments are needed. In recent years, exciting progress has been made in immunotherapies, including the rapid development of immune checkpoint inhibitors. Checkpoint blockades targeting the PD-1/PD-L1 axis have achieved effective clinical responses with acceptable toxicity by suppressing tumor progression and improving survival in several tumor types. In this review, we summarize recent advances in our understanding of the PD-1/PD-L1 signaling pathway, including the expression patterns of PD-1/PD-L1 and potential PD-l/PD-Ll-related therapeutic strategies for CC.

关键词： PD-1 PD-L1 immune checkpoint blockade antibody immunotherapy cervical cancer

Large and moderate deviation principles for susceptible-infected-removed epidemic in a random environment

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Frontiers of Mathematics in China 2021年第4期16卷 1117-1161页

作者： Xiaofeng XUE yumeng SHEN School of Science Beijing Jiaotong UniversityBeijing 100044China

We are concerned with SIR epidemics in a random environment on complete graphs,where edges are assigned with i.i.d,*** main results give large and moderate deviation principles of sample paths of this *** results generalize large and moderate deviation principles of the classic SIR models given by *** and ***-Kepgnou[***.,2017,54:905-920]and ***[Stochastic ***.,2019,140:49-80].

关键词： large deviation moderate deviation susceptible-infected-removed(SIR) epidemic random environment

Low-cost and fluoride-free synthesis of MFI zeolite nanosheets with enhanced stability for benzene alkylation with ethanol

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Journal of Energy Chemistry 2025年第1期 458-468页

作者： Peng Zhu Cun Liu Yiren Yu Guoshu Gao yumeng Zhao Xiongfu Zhang Guodong Liu Guohui Yang State Key Laboratory of Fine Chemicals School of Chemical Engineering Dalian University of Technology State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences

Zeolite nanosheets with a short b-axis thickness are highly desirable in lots of catalytic reactions due to their reduced diffusion resistance. Nevertheless, conventional synthesis methods usually require expensive structure-directing agents(SDAs), pricey raw materials, and eco-unfriendly fluorine-containing additives. Here, we contributed a cost-effective and fluoride-free synthesis method for synthesizing high-quality MFI zeolite nanosheets through a Silicalite-1(Sil-1) seed suspension and urea cooperative strategy, only with inexpensive colloidal silica as the Si source. Our approach was effective for synthesizing both Sil-1 and aluminum-containing ZSM-5 nanosheets. By optimizing key synthesis parameters,including seed aging time, seed quantity, and urea concentration, we achieved precise control over the crystal face aspect ratio and b-axis thickness. We also revealed a non-classical oriented nanosheet growth mechanism, where Sil-1 seeds induced the formation of quasi-ordered precursor particles, and the(010)crystal planes of these particles facilitated urea adsorption, thereby promoting c-axis-oriented *** obtained ZSM-5 nanosheets exhibited exceptional catalytic performance in the benzene alkylation with ethanol, maintaining stability for over 500 h, which is 5 times longer than traditional ZSM-5 catalysts. Furthermore, large-scale production of ZSM-5 nanosheets was successfully carried out in a 3 L highpressure autoclave, yielding samples consistent with those from laboratory-scale synthesis. This work marks a significant step forward in the sustainable and efficient production of MFI nanosheets using inexpensive and environmentally friendly raw materials, offering the broad applicability in catalysis.

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Shock wave standoff distance of near space hypersonic vehicles

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Science China(Technological Sciences) 2017年第8期60卷 1123-1131页

作者： HU yumeng HUANG HaiMing GUO Jin Institute of Engineering Mechanics Beijing Jiaotong University Beijing 100044 China

The shock wave standoff distances of near space hypersonic vehicles, which execute missions mainly at the altitude of 25 km to 55 km, are vital in aerothermodynamic analysis. The implicit finite volume schemes are derived from axisymmetric Navier-Stokes equations for chemical equilibrium flow, and programmed in FORTRAN. Taking a sphere cone for example, the effects of Much numbers （from 22 to 36） on the shock wave standoffdistance and the average density behind the shock are simulated at different altitudes from 25km to 55km. The numerical results illustrate that the turning point of the standoff distance is corresponding to that of the average density with the variation of Mach numbers. Based on the numerical results, we propose a formula for shock wave standoff distance, which is the function of the radius of the blunt body, the Mach number and the altitude in the atmosphere. Compared with previous correlations, the new formula can overcome the drawbacks of larger relative errors and complex calculations of the average density.

关键词： near space vehicles hypersonic flow standoff distance numerical simulation

FROM CRYSTALLINE BLOCK SLIPS TO DOMINANCE OF NETWORK STRETCHING——MECHANISMS OF TENSILE DEFORMATION IN SEMI-CRYSTALLINE POLYMERS

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Chinese Journal of Polymer Science 2002年第2期20卷 160-170页

作者： Y. men Univ Freiburg Fak Phys D-79104 Freiburg Germany

The mechanism of tensile deformation in semi-crystalline polymers was studied based on true stress-strain curvesobtained with the aid of a video-controlled tensile set-up. The deformation is affected by both the crystalline and theamorphous phases. However, the relative weights of the two portions change with the deformation stage. At lowdeformations the coupling and coarse slips of the crystalline blocks dominate the mechanical properties, which allows thesystem to maintain a homogeneous strain distribution in the sample. As the stretching increases, at a critical strain the forcegenerated from entangled fluid portions reaches a critical value to destroy the crystallites. The dominant deformationmechanism then changes into a disaggregation - recrystallization process.

关键词： Semi-crystalline polymer Deformation mechanism Network Mechanical property