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Effects of dry-wet cycles on the mechanical properties of sandstone with unloading-induced damage

Journal of Mountain Science 2024年第10期21卷 3474-3486页

作者： nan gan ZHANG Jiaming LUO Yi WANG Xinlong HU Zhongyi Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China

Sandstone is the fundamental material in various engineering and construction ***,the mechanical integrity of sandstone can be compromised by initial unloading damage resulting from activities such as engineering ***,this degradation is further exacerbated under periodic dry-wet environmental *** study investigated the effects of dry-wet cycles and unloading on the mechanical properties of jointed fine sandstone using uniaxial and triaxial compression *** tests were performed on rock samples subjected to varying unloading degrees and different numbers of dry-wet *** results demonstrate that with an increase in the unloading degree from 0%to 70%,there is a corresponding decrease in peak stress ranging from 10%to 33%.Additionally,the cohesion exhibits a reduction of approximately 20%to 25%,while the internal friction angle experiences a decline of about 3.5%to 6%.These findings emphasize a significant unloading ***,the degree of peak stress degradation in unloading jointed fine sandstone diminishes with an increase in confining pressure,suggesting that confining pressure mitigates the deterioration caused by dry-wet ***,as the number of dry-wet cycles increases,there is a notable decline in the mechanical properties of the sandstone,evidencing significant dry-wet *** the Drucker Prager criterion,this study establishes a strength criterion and fracture criterion,denoted asσ1(m,n)and,to quantify the combined impacts of dry-wet cycles and unloading on jointed fine sandstone,which provides a comprehensive understanding of its mechanical behavior under such conditions.

关键词： Unloading Dry-wet cycle Jointed fine sandstone Strength criterion fracture criterion Mechanical properties

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高精度固态调制器绝缘栅双极晶体管驱动电路

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强激光与粒子束 2024年第6期36卷 120-128页

作者：石秀倩何大勇李飞甘楠牟雅洁李京祎中国科学院高能物理研究所北京100049 中国科学院大学北京100049

加法器式固态调制器是一种使用绝缘栅双极晶体管(IGBT)控制储能电容放电来产生脉冲高压的装置,相比传输线型调制器,具有模块化、稳定性好、寿命长等优势。但IGBT的正常工作需要利用栅极驱动电路将控制信号进行放大才能实现,驱动电路的... 详细信息

加法器式固态调制器是一种使用绝缘栅双极晶体管(IGBT)控制储能电容放电来产生脉冲高压的装置,相比传输线型调制器,具有模块化、稳定性好、寿命长等优势。但IGBT的正常工作需要利用栅极驱动电路将控制信号进行放大才能实现,驱动电路的性能直接影响IGBT的开关特性,最终影响脉冲电压质量,尤其是驱动电路的导通抖动指标,这是影响脉冲电压精度的关键因素之一。根据加法器式固态调制器中IGBT的工作特性,以提高脉冲电压精度为目标,对驱动电路进行研究。分析了开关抖动对输出电压精度的影响,介绍了设计原理,研制了驱动电路板,并利用放电模块对其工作性能进行了实验测试。测试结果表明,该款驱动电路的导通抖动为300 ps,相比1 ns的商用驱动电路抖动压缩至1/3,在1 kV充电电压下,放电模块在0.5Ω的负载上放电,形成上升时间为500 ns、导通抖动峰、峰值在5 ns以下的脉冲电压,当发生退饱和故障时,驱动电路能够在4μs时间内关断IGBT,该款驱动电路满足高精度固态调制器的工作要求。

关键词：固态调制器脉冲电压精度绝缘栅双极晶体管栅极驱动电路导通抖动

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Genetic Diversity： Geographical Distribution and Toxin Profiles of Microcystis Strains （Cyanobacteria） in China

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Journal of Integrative Plant Biology 2007年第3期49卷 262-269页

作者： Zhong-Xing Wu nan-Qin gan Li-Rong Song State Key Laboratory of Freshwater Ecology and Biotechnology Institute of Hydrobiology the Chinese Academy of Sciences Wuhan 430072 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China

Twenty strains of Microcystis Kütz were isolated from different freshwater bodies in China to analyze the diversity, geographical distribution and toxin profiles. Based on whole-cell polymerase chain reaction of cpcBA-IGS nucleotlde sequence, the derived neighbor-joining （NJ） and maximum parsimony （MP） trees Indicate that these strains of Microcystis can be divided into four clusters. The strains from south, middle and north region of China formed distinct lineages, suggesting high diversity and a geographical distribution from south to north locations. Moreover, the results being indicating high variable genotypes of the strains of the Microcystis strains from the same lake show that there Is high diversity of Microcystis within a water bloom population. Comparing the results of the present study with those reported for compared with 43 strains of Microcystis from other locations, also reveals Chinese strains have high similarity with those from regions in the North Hemispherical. This suggests that the Microcystis strains In the world might have a geographical distribution. Analysis of 30 strains using the primers MCF/TER and TOX2P/TOX2M showed that there was no correlation between the gene of cpcBA-IGS and the presence of racy. Toxic strains were founded to be predominant in different water bodies throughout China.

关键词： diversity geographical distribution microcystin Microcystis

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Improved Differential Attack on 30-Round SIMON64

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Wuhan University Journal of Natural Sciences 2016年第1期21卷 75-83页

作者： WANG Gaoli gan nan LI Yue School of Computer Science and Technology Donghua University

In this paper we present an attack on 30-round SIMON64, which improves the best results on SIMON64 by 1 round. We use a 23-round differential characteristic which was proposed by Itai et al in 2015 to construct a 30-round extended differential characteristized by adding 4 rounds on the top and 3 round on the bottom. Furthermore, we utilize all of the sufficient bit-conditions of the 30-round differential to compute a set of corresponding subkeys. Then we distribute the plaintext pairs over the 286 lists corresponding to the 86-bit subkeys. If a list contains two or more pairs, we regard the subkeys corresponding to the list as candidate subkeys. The time complexity of our attack on 30-round SIMON64/96 （SIMON64/128） is 286.2 （21182） with a success probability of 0.61, while the data complexity and the memory complexity are 263.3 and 290 bytes, respectively.

关键词： SIMON lightweight block cipher differential attack bit condition

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Timing of brain computed tomography for predicting neurological prognosis in comatose cardiac arrest survivors: a retrospective observational study

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World Journal of Emergency Medicine 2022年第5期13卷 349-354页

作者： gan-nan Wang Zhong-man Zhang Wen Chen Xiao-quan Xu Jin-song Zhang Department of Emergency the First Affi liated Hospital of Nanjing Medical UniversityNanjing 210029China Department of Radiology the First Affi liated Hospital of Nanjing Medical UniversityNanjing 210029China

BACKGROUND:To assess the association between relevant brain computed tomography(CT)parameters at different time and neurological prognosis in adult comatose survivors after cardiac arrest(CA).METHODS:A total of 94 CA patients who underwent early and late CT scans(within 24 h and 24 h to 7 d respectively after CA)between January 2018 and April 2020 were enrolled in this retrospective *** to the Cerebral Performance Category(CPC)score at hospital discharge,the patients were divided into either a good outcome(CPC 1-2)group or a poor-outcome group(CPC 3-5).The grey-to-white matter ratio(GWR)and the proportion of cerebrospinal fluid volume(pCSFV)were *** predicting poor outcomes,the prognostic performance of relevant CT parameters was evaluated,and the comparison analysis(expressed as the ratio of parameters in late CT to those in the early CT)of diff erent CT time was ***:Totally 26 patients were in the good-outcome group,while 68 patients were in the poor-outcome *** putamen density,GWR,and pCSFV in late CT were significantly lower in the poor-outcome group(Pganglia24 h after CA may be a good choice as a neuroimaging approach to evaluating *** predict neurological prognosis,comparison analysis of diff erent CT time can be used as another promising tool in comatose CA survivors.

关键词： Cardiac arrest Brain computed tomography Cerebral edema Coma Prognosis

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基于模糊方法的地铁车站通风空调系统质量控制要点评价

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工程质量 2024年第3期42卷 1-6页

作者：张凯甘楠张浡马晓蕾刁姝文北京市建设工程安全质量监督总站北京101117

论文针对地铁车站通风空调系统质量现状难以量化的问题,建立地铁车站通风空调系统质量控制要点评价体系。将模糊层次分析法应用到地铁车站通风空调系统质量控制要点评价中,充分考虑各元素评价过程中的不确定性,最终绩效评价为89.46。此... 详细信息

论文针对地铁车站通风空调系统质量现状难以量化的问题,建立地铁车站通风空调系统质量控制要点评价体系。将模糊层次分析法应用到地铁车站通风空调系统质量控制要点评价中,充分考虑各元素评价过程中的不确定性,最终绩效评价为89.46。此结果表明该地铁站通风空调系统施工质量为良好,其中空调风系统和制冷系统的质量控制是体系中的重中之重。同时,在之后的监督过程中,更应加强空调风系统和制冷系统的质量监督力度。

关键词：地铁车站模糊层次分析法通风空调系统质量评价质量监督

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Orolingual angioedema during thrombolysis in acute ischemic stroke:A case report

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World Journal of Emergency Medicine 2022年第1期13卷 71-73页

作者： Yao Wang Hao Sun gan-nan Wang Xiao-min Zhang Jin-song Zhang Department of Emergency Medicine Jiangsu Province Hospitalthe First Affi liated Hospital of Nanjing Medical UniversityNanjing 210029China

Dear editor,According to the World Health Organization,ischemic heart disease and stroke were the top 2leading causes of death in 2019.[1]In the past few years,intravenous recombinant tissue-type plasminogen activator(rt-PA)has been a significantly effective treatment to increase survival and reduce mortality in acute ischemic stroke.[2,3]However,as the number of patients who receive alteplase is increasing,a rare but potentially life-threatening adverse complication of alteplase administration is becoming more common-orolingual angioedema(OA).[4-6]

关键词： edema acute mortality

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Radio-frequency design and commissioning of a flexible waveguide for high-vacuum S-band applications

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Radiation Detection Technology and Methods 2020年第2期4卷 250-254页

作者： Xiang He Jian-She Cao Bing-Lin Deng Jing-Dong Liu nan gan Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China

Purpose Flexible waveguides,which allow for greater deformation as compared to traditional hard waveguides,are highly useful for simplifying waveguide system ***,the peak powers of these waveguides have been limited to several megawatts in non-vacuum ***,a novel flexible waveguide was developed for the S-band(2856 MHz)with the aim of facilitating the interconnection of two hard *** The flexible waveguide was composed of brass,and its surface was plated with oxygen-free high-conductivity copper for brazing with stainless steel flanges in a vacuum *** connecting the stainless steel flanges together,it can be applied to a high-vacuum *** The prototype exhibited good measurement results in low-power microwave tests;the results of a 72-h vacuum leak test showed satisfactory vacuum performance as well,and no obvious surface collapse was ***-power microwave commissioning was conducted between June and July 2019;the waveguide showed a maximum average power of approximately 2.7 *** Unfortunately,the prototype was damaged after reaching that power level,which indicates the need for further optimization of the fabrication *** our experiment,it is clear that the flexible waveguide cannot be used in large accelerators because of its average power limit.

关键词： S-band Flexible waveguide High vacuum Microwave commissioning

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Subtle structure tailoring of metal-free triazine luminogens for highly efficient ultralong organic phosphorescence

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Chinese Chemical Letters 2019年第11期30卷 1935-1938,F0003页

作者： Xuan Wang nan gan Mingxing Gu Kun Ling Chaoqun Ma Huili Ma Wei Yao Yujian Zhang Huifang Shi Zhongfu An Wei Huang Key Laboratory of Flexible Electronics(KLOFE)&Institute of Advanced Materials(IAM) Jiangsu National Synergistic Innovation Center for Advanced Materials(SICAM)Nanjing Tech University(Nanjing Tech)Nanjing 211816China Department of Materials Chemistry Huzhou UniversityHuzhou 313000China Shanxi Institute of Flexible Electronics(SIFE) Northwestern Polytechnical University(NPU)Xi'an 710072China

Ultralong organic phosphorescent materials have invoked considerable attention for their great potential in sensing,data encryption,information anti-counterfeiting and so ***,effective ways to achieve highly efficient ultralong organic phosphorescence(UOP)in metal-free organic materials remain a great ***,we designed three isomers based on asymmetric triazines with various bromine substituted ***,phosphorescence efficiency of p-BrAT in solid state can reach up to 9.7%with a long lifetime of 386 ms,which was one of the highest efficient UOP materials reported so *** calculations further demonstrated that para-substitution exhibited the most effective radiative transition for triplet *** results will provide an effective approach to achieving highly efficient UOP materials.

关键词： Ultralong organic phosphorescence(UOP) Isomerism Crystal engineering H-aggregation Intermolecular interactions

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胸锁乳突肌缝线定位联合肌间隙注水分离在经腋窝无充气腔镜甲状腺手术中的应用

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中国普通外科杂志 2024年第5期33卷 780-787页

作者：郑向欣杨鹏管晓青陈志峰许南敢田明明黄超王付超佘欣远王前玉朱小朝江苏省宿迁市第一人民医院/徐州医科大学宿迁临床学院甲乳外科江苏宿迁223800 江苏省宿迁市第一人民医院/徐州医科大学宿迁临床学院病理科江苏宿迁223800

背景与目的:目前较为常用的腔镜甲状腺手术入路主要有经腋窝入路、经胸乳入路及经口入路等。经腋窝入路相较于其他术式,其利用颈部肌肉的自然间隙建腔,在颈前带状肌深面显露甲状腺并进行手术操作,对颈部功能影响较小,而且无需充CO_(2),... 详细信息

背景与目的:目前较为常用的腔镜甲状腺手术入路主要有经腋窝入路、经胸乳入路及经口入路等。经腋窝入路相较于其他术式,其利用颈部肌肉的自然间隙建腔,在颈前带状肌深面显露甲状腺并进行手术操作,对颈部功能影响较小,而且无需充CO_(2),对心脑血管影响较小,因此近年来越来越被临床医生所接受。经腋窝入路腔镜甲状腺手术中寻找胸锁乳突肌肌间隙是该术式的一大难点,在此步骤中较多初学者不能准确定位肌间隙,进而增加了手术时间及创伤。为此,笔者中心对经腋窝无充气腔镜甲状腺手术作了一定的改进,降低术中寻找肌间隙的难度。本研究对该改良术式的近期疗效与安全性进行评估,为其在临床中的应用提供依据。方法:回顾性分析2023年1月—2023年5月江苏省宿迁市第一人民医院甲乳外科收治的46例甲状腺癌患者的临床资料。其中,23例接受改良经腋窝入路免充气腔镜下甲状腺手术(观察组),另23例接受常规经腋窝入路免充气腔镜下甲状腺手术(对照组)。观察组患者术前超声引导下在胸锁乳突肌胸骨部与锁骨部之间的间隙内注水分离,扩大肌间隙,然后缝线定位胸锁乳突肌胸骨部后缘,准确进入肌间隙后,按照常规经腋窝入路腔镜甲状腺手术方法实施手术。结果:两组患者一般资料无明显差异(均P>0.05),具有可比性。观察组平均手术时间明显短于对照组(65.6 min vs.87.2 min,P0.05)。观察组有1例出现腋窝皮下血肿,经抽液、包扎后改善,余患者均无呼吸困难、声音嘶哑、手足麻木、饮水呛咳等并发症发生。术后3个月,两组患者颈部疼痛评分及颈部损伤指数、吞咽障碍指数比较,差异均无统计学意义(均P>0.05)。所有患者术后均口服左旋甲状腺素钠片行个体化促甲状腺激素(TSH)抑制治疗,随访期间无患者出现复发转移。结论:术前行超声引导下胸锁乳突肌缝线定位联合肌间隙注水分离操作方便、实用,便于术中寻找肌间隙,降低了经腋窝无充气腔镜甲状腺手术整体手术难度,具有较好的临床应用价值。

关键词：甲状腺肿瘤甲状腺切除术内窥镜腋窝入路

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