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Channel quality-to-interference ratio quantization criterion for limited feedback beamforming in MIMO systems

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The Journal of China Universities of Posts and Telecommunications 2012年第3期19卷 17-21页

作者： LIU Yan-fei LU Guang-yue sun bao-yu Xi'an University of Posts and Telecommunications Xi'an 710121China

The discrete Fourier transform （DFT）-based codebook is employed in this paper to quantize channel state information so that the amount of feedback can be reduced in the multiple input multiple output （MIMO） downlink of long term evolution （LTE） system. And a novel beamforming （BF） scheme based on the proposed channel quality-to-interference （QIR） quantizing criteria is developed, which uses only the index of the optimal codebook for the beamforming at the base station （BS）, and dramatically reduces the amount of feedback. The proposed BF scheme jointly considers the influences of the quality of the quantized channels and the mutual interference among the sub-channels. The extensive simulation results verify that throughput of the proposed BF scheme is better than that of the random BF with a little feedback, and that of the eigen-beamforming even under low signal noise ratio （SNR） scenario.

关键词： DFT-based codebook beamforming channel quality-to-interference ratio

Magnetic-Field-Induced Weak Order in Nematic Liquid Crystals Formed by Biaxial Molecules

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Chinese Physics Letters 2000年第10期17卷 749-751页

作者： ZHANG Zhi-Dong ZHANG De-Xian sun yu-bao Department of Physics Hebei University of TechnologyTianjin 300130

Nematic liquid crystal system of interacting biaxial particles via dispersion forces is *** molecular orienting potential form in a magnetic field is given for the first *** ordered isotropic phase is treated in the two-particle cluster *** account of the molecular biaxiality,it is found that the ratio of the lowest supercooling temperature T^(*)to the nematic-isotropic phase transition temperature TC approaches the observed value,and the validity of the mean field theory is clarified.

关键词： Nematic isotropic clarified

Forced boiling of nonazeotropic immiscible mixture in a supercapillary microchannel array for ultra-high heat flux removal with chip junction temperature below 85℃

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Science China(Technological Sciences) 2024年第5期67卷 1364-1380页

作者： sun Bo bao yuChen TIAN Tong LI Ji School of Engineering Science University of Chinese Academy of SciencesBeijing100049China Laboratory of Advanced Thermal Management Technologies School of Engineering ScienceUniversity of Chinese Academy of SciencesBeijing100049China

In this study,a structure-optimized two-phase microchannel heat sink with sintered submicron nucleation sites was developed and *** copper-based microchannels had a rectangular cross-section with an equivalent hydraulic diameter of 222μ*** subcooled flow boiling characteristics were comprehensively compared between pure HFE-7100 and a non-azeotropic,immiscible binary mixture of HFE-7100 and water,considering heating areas of 1 and 5 cm^(2).The total heating power input to the test section were 100–1500 and 250–3000 W for a 1 and 5 cm^(2)heat source,respectively,with a flow rate ranging from 50 to150 L/*** to pure HFE-7100,the non-azeotropic immiscible binary mixture of HFE-7100/water in the sintered porous microchannels exhibited a much higher overall heat transfer coefficient and lower power *** maintain the junction temperature of a high power electronic chip below 85℃,the proposed supercapillary microchannel heat sink could effectively dissipate the heat flux of 1275 W/cm^(2)over 1 cm^(2)heat source and 500 W/cm^(2)over 5 cm^(2)heat *** addition,the volume ratio of the binary mixture strongly influence the two-phase flow heat transfer *** optimal volume ratio exist in terms of the thermal resistance–pumping power minimization(HFE-7100:water=2:8 is recommended in this study).The findings of this investigation on the flow boiling properties of non-azeotropic immiscible mixtures help fill a gap in the related field.

关键词： microchannel sintered powder coating submicron nucleation cavities nonazeotropic immiscible ultra-high heat flux

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压电式微位移机构动态特性研究

压电与声光 2007年第6期29卷 653-655页

作者：孙宝玉长春工业大学机电学院吉林长春130012

压电陶瓷驱动器在较高电场的作用下将产生严重的非线性,从而影响其定位精度。压电陶瓷驱动器的非线性不仅与材料的非线性、蠕变、滞后等因素有关,还与器件的动态响应特性有关。动态响应的迟滞非线性是影响压电式微位移驱动器控制性能的... 详细信息

压电陶瓷驱动器在较高电场的作用下将产生严重的非线性,从而影响其定位精度。压电陶瓷驱动器的非线性不仅与材料的非线性、蠕变、滞后等因素有关,还与器件的动态响应特性有关。动态响应的迟滞非线性是影响压电式微位移驱动器控制性能的一个关键因素,直接关系到控制精度的提高。该文采用前馈控制同数字比例、积分和微分环节(PID)控制相结合的复合控制算法对一维压电式微位移机构的控制过程进行校正补偿,建立了动态特性的闭环校正控制系统。实测结果表明,机构的动态响应时间显著缩短,实现了机构的快速响应。

关键词：压电陶瓷驱动器微位移机构动态特性数字PID控制非线性

Design optimization and testing of a morphing leading-edge with a variable-thickness compliant skin and a closed-chain mechanism

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Chinese Journal of Aeronautics 2024年第7期37卷 285-300页

作者： Zhigang WANG Xiasheng sun yu YANG Wenjie GE Daochun LI Jinwu XIANG Panpan bao Qi WU Andrea DA RONCH School of Aeronautical Science and Engineering Beihang UniversityBeijing 100191China National Key Laboratory of Strength and Structural Integrity Aircraft Strength Research Institute of ChinaXi’an 710065China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Faculty of Engineering and Physical Sciences University of SouthamptonSouthampton SO171JBUK

Climate warming and the increased demand in air travels motivate the aviation industry to urgently produce technological *** of the most promising innovations is based on the smoothly continuous morphing leading-edge *** study proposes a two-step process for the design of a morphing leading-edge,including the optimization of the outer variable-thickness composite compliant skin and the optimization of the inner kinematic *** the compliant skin design,an optimization of the variable thickness composite skin is proposed based on a laminate continuity model,with laminate continuity constraint and other manufacturing *** laminate continuity model utilizes a guiding sequence and a ply-drop sequence to describe the overall stacking sequence of plies in different thickness regions of the complaint *** the inner kinematic mechanism design,a coupled four-bar linkage system is proposed and optimized to produce specific trajectories at the actuation points on the stringer hats of the compliant skin,which ensures that the compliant skin can be deflected into the aerodynamically optimal ***,a morphing leading-edge is manufactured and *** results are compared with numerical predictions,confirming the feasibility of the morphing leading-edge concept and the overall proposed design approach.

关键词： Optimization Design Morphing wing Compliant skin Kinematics Leading-edge Control surfaces

Multifaceted role of microRNAs in gastric cancer stem cells: Mechanisms and potential biomarkers

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World Journal of Gastrointestinal Oncology 2024年第2期16卷 300-313页

作者： Qian-Hui sun Zi-yu Kuang Guang-Hui Zhu bao-Yi Ni Jie Li Department of Oncology Guang'anmen HospitalChina Academy of Chinese Medical SciencesBeijing 100053China Graduate College Beijing University of Traditional Chinese MedicineBeijing 100029China Department of Oncology Heilongjiang University of Chinese MedicineHarbin 150040Heilongjiang ProvinceChina

MicroRNAs(miRNAs)have received much attention in the past decade as potential key epigenomic regulators of tumors and cancer stem cells(CSCs).The abnormal expression of miRNAs is responsible for different phenotypes of gastric cancer stem cells(GCSCs).Some specific miRNAs could be used as promising biomarkers and therapeutic targets for the identification of *** review summarizes the coding process and biological functions of miRNAs and demon-strates their role and efficacy in gastric cancer(GC)metastasis,drug resistance,and apoptosis,especially in the regulatory mechanism of *** shows that the overexpression of onco-miRNAs and silencing of tumor-suppressor miRNAs can play a role in promoting or inhibiting tumor metastasis,apart from the initial formation of *** also discusses the epigenetic regulation and potential clinical applications of miRNAs as well as the role of CSCs in the pathogenesis of *** believe that this review may help in designing novel therapeutic approaches for GC.

关键词： Gastric cancer,Cancer stem cells MicroRNAs Epigenetics Therapeutic target

Impact of uterine artery embolization on ovarian function and pregnancy outcome after uterine-fibroids treatment:A prospective study

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World Journal of Clinical Cases 2024年第15期12卷 2551-2559页

作者： Jing-Lei Liu Zhi-Hui Liang bao Cui Jian-yu Liu Li sun Department of Interventional Treatment 980(Bethune International Peace)Hospital of PLA Joint Logistics Support ForcesShijiazhuang 050082Hebei ProvinceChina Department of Obstetrics and Gynecology 980(Bethune International Peace)Hospital of PLA Joint Logistics Support ForcesShijiazhuang 050082Hebei ProvinceChina

Uterine fibroids are benign tumors that originate from smooth muscle cells of the *** is the most common gynecological disorder,affecting up to 80%of women of reproductive *** fibroids can cause various symptoms such as abnormal uterine bleeding,pelvic pain,infertility,and pregnancy *** treatment options for uterine fibroids include medical therapy,surgical intervention,and minimally invasive *** To compare ovarian function of women with uterine fibroids who did or did not undergo uterine artery embolization(UAE).METHODS This prospective cohort study enrolled 87 women with symptomatic uterine fibroids who underwent UAE,and 87 women with the same symptoms who did not undergo UAE but received conservative management or other *** two groups were matched for age,body mass index,parity,and baseline characteristics of uterine *** primary outcome was ovarian function that was evaluated by serum levels of follicle-stimulating hormone(FSH),luteinizing hormone(LH),estradiol(E2),and anti-Müllerian hormone(AMH),as well as ovarian reserve tests,such as antral follicle count(AFC)and ovarian volume(OV).The secondary outcome was fertility that was evaluated based on the menstrual cycle,ovulation,conception,pregnancy,and *** participants were followed-up for 36 months and assessed at 1,3,6,12,24,and 36 months after *** The study found that the most common minor complication of UAE was postembolization syndrome in 73.6% of women,resolving within a *** significant differences were observed between the UAE group and the control group in serum levels of reproductive hormones(FSH,LH,E2,AMH)and ovarian reserve indicators(AFC,OV)at any point up to 36 months ***,there were no significant differences in conception,pregnancy,or delivery rates,with the average time to conception and gestational age at delivery being similar between the two *** weights were also ***

关键词： Uterine fibroids Uterine artery embolization Ovarian function Fertility Pregnancy outcome Embolic agent

Persistent Variations in the East Asian Trough from March to April and the Possible Mechanism

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Advances in Atmospheric Sciences 2024年第4期41卷 737-753,I0002-I0004页

作者： Shui yu Jianqi sun Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The East Asian trough(EAT)profoundly influences the East Asian spring *** this study,the relationship of the EATs among the three spring months is *** analysis shows that the variation in March EAT is closely related to that of April *** empirical orthogonal function(EEOF)analysis also confirms the co-variation of the March and April *** positive/negative EEOF1 features the persistent strengthened/weakened EAT from March to *** investigation indicates that the variations in EEOF1 are related to a dipole sea surface temperature(SST)pattern over the North Atlantic and the SST anomaly over the tropical Indian *** dipole SST pattern over the North Atlantic,with one center east of Newfoundland Island and another east of Bermuda,could trigger a Rossby wave train to influence the EAT in March−*** SST anomaly over the tropical Indian Ocean can change the Walker circulation and influence the atmospheric circulation over the tropical western Pacific,subsequently impacting the southern part of the EAT in March−*** the SST factors,the Northeast Asian snow cover could change the regional thermal conditions and lead to persistent EAT anomalies from March to *** three impact factors are generally independent of each other,jointly explaining large variations in the EAT ***,the signals of the three factors could be traced back to February,consequently providing a potential prediction source for the EAT variation in March and April.

关键词： spring East Asian trough sea surface temperature snow cover

Cooperative game penetration guidance for multiple hypersonic vehicles under safety critical framework

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Chinese Journal of Aeronautics 2024年第1期37卷 247-255页

作者： Jieqing CHEN Ruisheng sun yu LU School of Energy and Power Engineering Nanjing University of Science and TechnologyNanjing 210094China

The rapid development of the anti-missile weapon technology brings new challenges to the cooperative penetration strategy solution and the guidance law design for Hypersonic Vehicles(HVs).This paper studies the coordinated game penetration guidance problem for multiple hypersonic vehicles faced with space threat areas.A scheme for seeking cooperative game penetration guidance strategy under safety critical control framework is *** this scheme,a multiHV cooperative game model is proposed in a minimum optimization form which can simplify the solving process and accelerate the computing ***,a second-order control barrier function is developed to transform the implicit nonlinear constraints of the proposed model into linear *** order to obtain better performance of guidance strategy,a composite guidance law under the safety critical control framework is presented to allocate guidance strategies appropriately in the whole *** is shown that the proposed scheme can guarantee successful penetration while avoiding threat ***,a comparative simulation with a two-on-three game is conducted to verify the effectiveness of the proposed method.

关键词： Hypersonic vehicles Safety critical control Penetration game Space constraints Cooperative guidance