检索结果-南通市图书馆

Conceptual design of the CEPC dumping system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Radiation Detection Technology and Methods 2023年第2期7卷 220-226页

作者： Guangyi Tang Qiongyao Liu haoyu shi Xiaohao Cui Zhongjian Ma Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China

Background The circular electron–positron collider(CEPC)is a double-ring collider proposed by Chinese *** will be operated at centre-of-mass energy of 240,90,160 GeV and maybe also 360 *** The total energy stored in the collider is up to 20 *** is important to extract beams safely and not to damage the *** this paper,a dumping system including dilution kickers and absorber core with iron shielding is *** The Monte Carlo code FLUKA is used to obtain the deposited energy and dose-equivalent *** temperature rises are calculated assuming no heat *** Compared with the melting point and upper limit of dose equivalent,the magnets parameters are determined and the dimensions of the core and shielding are *** The design of the dumping system meets the requirement that the energy stored in the collider can be absorbed safely.

关键词： CEPC Dumping system FLUKA Temperature rise Dose equivalent

Estimation of the radiation backgrounds in the CEPC vertex detector

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Radiation Detection Technology and Methods 2022年第2期6卷 170-178页

作者： Wei Xu haoyu shi Hongbo Zhu Ke Li Sha Bai Xinchou Lou Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physics Zhejiang UniversityHangzhou 310058China Department of Physics University of WashingtonSeattleWA 98195USA

Background The Circular Electron-Positron Collider(CEPC)is aimed for precision measurements of the Higgs boson properties and the electroweak *** achievable precision will be largely dependent on the controlled level of radiation backgrounds,which requires an optimized design of the interaction region to assure the optimal performance of both the accelerator and the *** In this article,the latest results on the radiation backgrounds are reported based on the accelerator parameters and the detector design presented in the CEPC conceptual design *** For the different sources of radiation backgrounds,simulation steps consisting of generation,tracking,and detector simulation were *** backgrounds from the processes of synchrotron radiation,pair production,radiative Bhabha scattering,beam gas Bremsstrahlung scattering,and beam thermal photon scattering were considered for the accel-erator operating at the different centre-of-mass energies(HZ threshold,WW threshold,and Z pole).Possible mitigation methods of masks and/or collimators were introduced to suppress the radiation backgrounds,together with the careful opti-mization of the interaction region *** the improved tracking methods during simulation,the accuracy and reliability of the results were *** addition,the radiation backgrounds on the CEPC vertex detector were estimated,and the pair-production was found to be the most important *** In the worst case of operation at the Z pole,the vertex detector would have to withstand a total ionization dose of 5.6 Mrad per year and a non-ionization energy loss(shown in 1 MeV neutron equivalent)of 1.06×10^(13)n_(eq)/cm^(2)per year.

关键词： CEPC Interaction region Beam-induced background Vertex detector

Radiation protection designs of the linac for the HEPS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Radiation Detection Technology and Methods 2021年第4期5卷 576-585页

作者： Qiongyao Liu Zhongjian Ma Qingbiao Wu haoyu shi Gang Zhang Huijie Zhang Pingcheng Liu Qingbin Wang Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China University of Chinese Academy of Sciences Beijing 100049China Shandong Institute of Advanced Technology Shandong 250000China

Purpose The high-energy photon source(HEPS)is the first fourth-generation light source under construction in *** is designed to operate at an average current of 200 mA stored beam current with a top-up model at 6 GeV *** the linac radiation shielding design,a suitable beam loss scenario,optimized thickness for the bulk shielding and detailed structure design for dumps should be *** this paper,the beam loss scenarios were determined and categorized as normal;the dose limits were presented;using these scenarios and the dose limits,the thickness of the linac tunnel was calculated and detailed designs of the main beam dumps were *** material selection and size setting of the low-power electron beam dump were *** The Monte Carlo code is a good choice to simulate the radiation *** the ishiELD11 was used to verify the simulation *** and conclusion The designs of the linac bulk shield and dumps satisfied the requirements of radiation protection.

关键词： HEPS,Linac Radiation shielding design Dump FLUKA ishiELD11

Calcium requirements for Chinese adults by cross-sectional statistical analyses of calcium balance studies： an individual participant data and aggregate data meta-regression

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2014年第24期127卷 4250-4257页

作者： Fang Aiping Li Keji shi haoyu He Jingjing Li He Department of Nutrition and Food Hygiene Peking University Health Science Center Haidian District Beijing 100191 China

Background Chinese dietary reference intakes for calcium are largely based on foreign studies. We undertook meta- regression to estimate calcium requirements for Chinese adults derived from calcium balance data in Chinese adults. Methods We searched PubMed, Cochrane CENTRAL, and SinoMed from inception to March 5, 2014, by using a structured search strategy. The bibliographies of any relevant papers and journals were also screened for potentially eligible studies. We extracted a standardized data set from studies in Chinese adults that reported calcium balance data. The relationship between calcium intake and output was examined by an individual participant data （IPD） and aggregate data （AD） meta-regression. Results We identified 11 metabolic studies in Chinese adults within 18-60 years of age. One hundred and forty-one IPD （n=35） expressed as mg/d, 127 IPD （n=32） expressed as *** body wt-l-d-1, and 44 AD （n=132） expressed as mg/d were collected. The models predicted a neutral calcium balance （defined as calcium output （Y） equal to calcium intake （C）） at intakes of 460 mg/d （Y=0.60C＋183.98） and 8.27 *** body wt-l.d-1 （Y=0.60C＋3.33） for IPD, or 409 mg/d （Y=0.66C＋139.00） for AD. Calcium requirements at upper intakes were higher than that at lower intakes in all these models. Conclusion Calcium requirement for Chinese adults 18-60 years of age approximately ranges between 400 mg/d and 500 mg/d when consuming traditional plant-based Chinese diets.

关键词： calcium requirement Chinese adults individual participant data aggregate data meta-regression

Anti-melanoma action of small molecular peptides derived from Brucea javanica(L.)*** in vitro

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Traditional Chinese Medical Sciences 2022年第1期9卷 85-91页

作者： Yi Zhao Huiyun Wang Yanyan Yin haoyu shi Dong Wang Fengjue Shu Rongchun Wang Lingzhi Wang School of Life Sciences Beijing University of Chinese MedicineBeijing102488China School of Traditional Chinese Medicine Beijing University of Chinese MedicineBeijing102488China Karna Limited Liability Company Atlanta30345USA Biology Institute Qilu University of Technology(Shandong Academy of Sciences)Jinan250103China

Objective:The morbidity of malignant melanoma keeps increasing *** has high risks of metastasis,drug resistance,and poor prognosis in ***,the available medicines used commonly,such as dacarbazine,temozolomide,the v-Raf murine sarcoma viral oncogene homolog B1(BRAF)inhibitor vemurafenib,and the programmed cell death protein 1 inhibitor pembrolizumab,have some limitations at some ***,a more effective therapeutic strategy is still urgently ***:In this study,Brucea javanica(L.)*** were hydrolyzed with pepsin,then ultra-filtrated to collect small molecular peptides(≤3 kDa).The peptides were then analyzed by antiproliferative assay,cell-cycle distribution,apoptosis assay,and in vitro wound-scratch ***,western blotting was conducted to elucidate the underlying anti-melanoma ***:The small molecular peptide from *** significantly inhibited malignant melanoma cell proliferation with the IC_(50) of 2.72 mg/mL for 72 *** analysis indicated that *** peptides arrested cell cycle at the S and G2/M phases and induced apoptosis by upregulating p21,p53,Bax,caspase-3,and cleaved PARP while downregulating Bcl-2 *** inhibitory migration effects were also confirmed by wound-healing ***:The small molecular biopeptides from *** may be a promising bioactive agent candidate for melanoma treatment.

关键词： Brucea javanica(L.)Merr. Melanoma Globulin In vitro wound-scratch assay Peptide Cell-cycle assay Apoptosis assay Hydrolyze

Mechanical design of the horizontal collimator for HEPS storage ring

在线全文

学校读者我要写书评

暂无评论

Radiation Detection Technology and Methods 2022年第4期6卷 451-459页

作者： Liuxu Zong Haijing Wang Chunhua Li Huamin Qu Lei Wu Zihao Wang Yaliang Zhao Guangyi Tang Hao Yang Na Wang haoyu shi Institute of High Energy Physics Chinese Academy of ScienceBeijing 100049China Beijing Research Institute of Mechanical and Electrical Technology China Academy of Machinery Science and Technology GroupBeijing 100083China University of Chinese Academy of Science Beijing 100049China

Background Horizontal collimators in the storage ring of high energy photon source(HEPS)are used to localize the majority of the particle loss,making it possible to set local ***,movable jaws of the collimators are also designed as beam dumps for the machine protection,to absorb and scatter the mis-steered *** of the compact lattice,each collimator should be installed between the limited space of 240 mm in the beam *** is necessary for the collimators to have good thermal dissipation ability to endure the synchrotron radiation and HOM load,as well as good resistance to thermal-shock from sudden beam loss simultaneously,which brings great challenges to the *** The purpose of this paper is to introduce the designing scheme of the collimators in HEPS,including the structure design and the analyses of the key *** Thermal and mechanical calculation has been done,based on which the jaw structure has been ***,the modal analysis of the whole magnet-collimator-support assembly has been studied to optimize the shields *** Graphite will be used as the tip for movable jaws in the collimators,which is attached to copper by vacuum *** maximum temperature of the jaw during normal operation is 131°C,while maximum stress of the graphite–copper weld joint is 15.6 *** tip can resist thermal shock caused by whole mis-steered *** frequency of the standard assembly is acceptable for *** The results of calculations indicate that the present structure can work well for considered operating modes.

关键词： Collimator Structural design Finite element method(FEM)

龙门山断裂带及附近区域地貌形成与地应力演化机制研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

地震学报 2018年第3期40卷 332-340页

作者：师皓宇马念杰中国矿业大学(北京)资源与安全工程学院中国北京100083 华北科技学院安全工程学院中国北京101601

以龙门山附近区域水平运动特性以及深部岩体力学特性为基本条件,采用FLAC模拟软件计算分析了龙门山断裂带及附近区域的地貌形成过程和地应力演化机制。研究结果认为:区域板块运动是龙门山地貌形成的重要原因,龙门山3条断层在62万年内的... 详细信息

以龙门山附近区域水平运动特性以及深部岩体力学特性为基本条件,采用FLAC模拟软件计算分析了龙门山断裂带及附近区域的地貌形成过程和地应力演化机制。研究结果认为:区域板块运动是龙门山地貌形成的重要原因,龙门山3条断层在62万年内的相对滑移速率分别为1.53,0.245和0.458 mm/a,与实际监测结果基本吻合;龙门山断裂带左侧呈抬升趋势,右侧四川盆地的垂向运动保持稳定;随着区域板块的运动,3条断裂带附近主应力的变化均经历了3个阶段,即应力低态稳定阶段,应力增高阶段和应力高态稳定阶段,最终形成应力积聚—应力释放的平衡局面;断裂带附近的最大、最小主应力比值介于2.94—3.71之间,平均为3.3,与实际监测结果基本吻合。由此可以推断,龙门山及附近区域将长期处于高偏应力环境,即长期处于"应力累积—进入临界状态—发震—新的应力累积"的地震周期。

关键词：区域构造运动龙门山断裂带数值模拟地貌形成地应力演化

在线全文

学校读者我要写书评

暂无评论

高压密封注浆试验系统的研制与应用

煤矿安全 2015年第10期46卷 111-113,116页

作者：田多师皓宇华北科技学院安全工程学院北京101601

为研究高应力、高水压、高注浆压力条件下注浆浆液的扩散特征,研制了高压密封注浆试验系统。该试验系统由5个子系统组成,即装载系统、地应力加载和稳压系统、水压力加压与稳压系统、高压注浆系统、图像数据采集与处理系统。该试验系统... 详细信息

为研究高应力、高水压、高注浆压力条件下注浆浆液的扩散特征,研制了高压密封注浆试验系统。该试验系统由5个子系统组成,即装载系统、地应力加载和稳压系统、水压力加压与稳压系统、高压注浆系统、图像数据采集与处理系统。该试验系统可研究地应力、水压力、注浆压力与化学浆液扩散半径之间的关系,可研究化学浆液在被注介质内部的渗流与孔隙渗透规律。利用该试验系统进行注浆试验,根据试验结果给出合理的注浆参数,使平朔公司井工三矿综放工作面过风氧化带的注浆工程节约56%的注浆材料。

关键词：高压密封注浆注浆加固试验系统注浆材料围岩控制

在线全文

学校读者我要写书评

暂无评论

沿空留巷矿压显现规律模拟研究

中国煤炭 2012年第10期38卷 42-44页

作者：石建军师皓宇华北科技学院安全工程学院河北省三河市065201

结合冀中能源股份公司葛泉矿1528工作面运输巷的工程条件,在关键层理论研究成果基础上,通过计算机数值模拟的方法,建立了反映岩层基本特征的力学模型,研究了留巷上方顶板断裂的应力特征、变形特征和破坏特征。

关键词：沿空留巷采动影响数值模拟矿压显现