检索结果-南通市图书馆

Influence of cutterhead opening ratio on soil arching effect and face stability during tunnelling through non-uniform soils

引用

Underground Space 2024年第4期17卷 45-59页

作者： Xue-Jian Chen pei-pei fang Qiu-Nan Chen Jun Hu Kai Yao Yong Liu State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan 430072China Hubei Technology Innovation Center for Smart Hydropower Wuhan 430000China College of Civil Engineering Anhui Jianzhu UniversityHefei 230601China School of Civil Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Civil and Architectural Engineering Hainan UniversityHaikou 570228China School of Qilu Transportation Shandong UniversityJinan 250002China

Tunnelling has increasingly become an essential tool in the exploration of underground space.A typical construction problem is the face instability during tunnelling,posing a great threat to associated *** face instability often occurs with the soil arching *** study investigates the combined effect of cutterhead opening ratio and soil non-uniformity on soil arching effect and face stability,via conducting random finite-element analysis coupled with Monte–Carlo *** results underscore that the face stability is strongly associated with the evolution of stress *** obtained stability factors in the uniform soils can serve as a reference for the design of support pressure in practical tunnelling *** addition,non-uniform soils exhibit a lower stability factor than uniform soils,which implies that the latter likely yields an underestimated probability of face *** tunnel face is found to have a probability of failure more than 50%if the spatial non-uniformity of soil is *** the end,a practical framework is established to determine factor of safety(FOS)corresponding to different levels of probability of face failure considering various opening ratios in non-uniform *** required FOS is 1.70 to limit the probability of face instability no more than 0.1%.Our findings can facilitate the prediction of probability of instability in the conventionally deterministic design of face pressure.

关键词： Tunnel Face stability Soil arching effect Cutterhead opening ratio Non-uniform soil Random field

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Formation mechanism of multiple spallation and its penetration induced by shear localization in NiTi alloy under implosion loading

引用

Matter and Radiation at Extremes 2025年第1期10卷 81-97页

作者： Xianye Wu Xiaoyang pei Xiang Chen Hao Zhang Jin Wang Xin Yang Meizhen Xiang Shang Gao fang Wang School of Materials and Energy Southwest UniversityChongqing 400715China Institute of Fluid Physics China Academy of Engineering PhysicsMianyang 621999China State Key Laboratory of Nuclear Physics and Technology Center for Applied Physics and TechnologyPeking UniversityBeijing 100871China School of Environment and Resource Southwest University of Science and TechnologyMianyang 621010China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China

This study uses nonequilibrium molecular dynamics simulations to explore the dynamic failures and deformation mechanisms of a cylindrical shell composed of nanocrystalline nickel-titanium alloy under implosion *** discover that some individual spall planes are sequentially generated in the material along the propagation of a radial stress wave,indicative of the formation of multiple *** larger grain sizes,void nucleation at the first spallation occurs in a coexisting intergranular/transgranular manner,whereas with decreasing grain size,voids tend to nucleate along the grain ***,the spall strength exhibits a transition from an inverse Hall-Petch to a Hall-Petch *** larger grain sizes,at the secondary spallation,localized shearing zones and grain boundaries provide potential void-nucleated ***,the formation of shear deformation bands promotes grain refinement,contributing to a reduction in the dislocation-induced strengthening ***,a lower spall strength is produced,in contrast to the first *** the grain size becomes smaller,voids nucleate mostly along grain boundaries,and plastic deformation is dominated by dense grain ***,the high temperature caused by shear localization leads to material weakening,and in turn there is a significant decrease in the spall strength for the secondary spallation,compared with the ***,significant penetration between two spall planes is observed for large grain size,which can be attributed to the nucleation of voids on linking grain boundaries,with temperatures exceeding the melting point of the material.

关键词： grain alloy deformation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

阿片类药物诱导瘙痒的机制研究进展

引用

中国药理学通报 2025年第1期41卷 29-34页

作者：马芳周培岚苏瑞斌军事医学研究院国家安全特需药品全国重点实验室北京100850 南京中医药大学药学院江苏南京210046

瘙痒是临床使用阿片类药物镇痛的患者普遍存在的严重不良反应之一。大量研究已经阐明阿片类药物的镇痛机制,但阿片类药物诱导瘙痒的机制尚不明确,瘙痒与镇痛之间的关系也模糊不清。目前的研究发现,阿片类药物作用于μ、κ及δ阿片受体后... 详细信息

瘙痒是临床使用阿片类药物镇痛的患者普遍存在的严重不良反应之一。大量研究已经阐明阿片类药物的镇痛机制,但阿片类药物诱导瘙痒的机制尚不明确,瘙痒与镇痛之间的关系也模糊不清。目前的研究发现,阿片类药物作用于μ、κ及δ阿片受体后,直接或间接影响瘙痒关键受体——胃泌素释放肽受体的功能,进而影响瘙痒信息传递。神经介素B、神经肽Y、B型利钠肽等神经肽,以及其他受体如瞬时受体电位香草素1受体、N-甲基-D-天冬氨酸受体、5-羟色胺受体等,在吗啡诱导的瘙痒中也具有重要作用。此外,阿片类药物所致瘙痒的预防和治疗也是围手术期吗啡镇痛的难点和热点之一。因此,明确瘙痒的具体发生机制,对寻找新的研究思路及预防和治疗阿片类药物诱导的瘙痒具有重要意义。

关键词：阿片类诱导的瘙痒瘙痒与镇痛瘙痒机制阿片受体胃泌素释放肽受体瘙痒治疗

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

海藻植物发酵液饮料的研制

引用

食品工业科技 2017年第21期38卷 224-228,318页

作者：于配配方孝贤何鑫平吴彬彬胡梅梁岩晏斌深圳市中科台富科技有限公司广东深圳518131 中国科学院深圳先进技术研究院广东深圳518055 山东省食品药品检验研究院山东济南250101

实验原料以海带、紫菜、螺旋藻为主,果蔬为辅。海藻及富含淀粉质的果蔬匀浆提取液与复合植物糖渍浸提液混合后依次经红曲霉发酵、复合菌种发酵、醋酸菌发酵,后经后熟、过滤得到口感优良的海藻植物发酵液饮料。结果表明:红曲霉、复合菌... 详细信息

实验原料以海带、紫菜、螺旋藻为主,果蔬为辅。海藻及富含淀粉质的果蔬匀浆提取液与复合植物糖渍浸提液混合后依次经红曲霉发酵、复合菌种发酵、醋酸菌发酵,后经后熟、过滤得到口感优良的海藻植物发酵液饮料。结果表明:红曲霉、复合菌种及醋酸菌发酵时间分别为8、2、9 d,经单因素和正交实验优化后的其他发酵条件为:海藻提取液与植物提取液配比1∶2,起始发酵液可溶性固形物含量35%,复合菌种接种量5×10~7CFU/m L,乳酸菌和酵母菌接种数量比例15∶1。该饮料最终可溶性固形物含量33.6%,p H3.25,乳酸含量418 mg/L,乙酸含量1143 mg/L,乙醇含量低于0.5%,微生物指标均符合国家标准。该工艺与传统工艺相比发酵过程易于控制,产品口感优良,为解决海藻资源利用率低提供良好的示范作用。

关键词：海藻植物发酵红曲霉乳酸菌鲁氏接合酵母菌醋酸菌

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

陆缘弧岩浆寂静期花岗质岩浆成因:以青藏高原东南缘腾冲地块晚白垩世花岗岩为例

引用

岩石学报 2025年第1期41卷 91-111页

作者：赵少伟方肖雨文泰赖绍聪裴先治李佐臣长安大学地球科学与资源学院西安710054 大陆动力学国家重点实验室西北大学地质学系西安710069

陆缘弧岩浆活动常具有幕式特征,展现出弧岩浆爆发和寂静交替的现象。虽然对其律动特征广泛研究,但目前对于岩浆寂静期的岩浆成因机制了解较少。本文通过对比新特提斯洋俯冲相关的陆缘弧岩浆分布特征,以新特提斯洋俯冲过程中陆源弧岩浆... 详细信息

陆缘弧岩浆活动常具有幕式特征,展现出弧岩浆爆发和寂静交替的现象。虽然对其律动特征广泛研究,但目前对于岩浆寂静期的岩浆成因机制了解较少。本文通过对比新特提斯洋俯冲相关的陆缘弧岩浆分布特征,以新特提斯洋俯冲过程中陆源弧岩浆寂静期的腾冲地块晚白垩世花岗质岩石为研究对象,探讨其形成过程,为寂静期岩浆的成因动力学机制提供重要约束。腾冲地块户撒地区二长花岗岩锆石U-Pb年龄为73Ma,形成于新特提斯洋俯冲陆缘弧晚白垩世(85~65Ma)的岩浆寂静期,为准铝质-弱过铝质和钙碱质花岗岩,具有富集的Nd-Hf同位素,其源岩为高黎贡山群正变质片麻岩。通过区域对比,晚白垩世(85~65Ma)新特提斯洋低角度俯冲相关的陆源弧应为挤压环境,腾冲地块同期花岗岩类应形成于加厚地壳背景下。通过与爆发期(55~50Ma)岩石组合、地化特征、锆饱和温度和斜长石环带特征的对比,本文认为腾冲地块晚白垩世花岗岩类是加厚地壳长期热积累诱发的下地壳片麻岩部分熔融的结果。因此,在幔源岩浆低通量的陆缘弧寂静期,通过加厚地壳长期热积累可以在陆缘弧局部形成长英质岩浆。

关键词：岩浆寂静期腾冲地块晚白垩世花岗岩

来源：

维普期刊数据库博看期刊

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

考虑蠕变剪裂的拉格朗日元与离散元耦合方法及应用

引用

岩土力学 2025年第2期46卷 613-624页

作者：王学滨陈双印郑一方廖裴彬辽宁工程技术大学计算力学研究所辽宁阜新123000 辽宁工程技术大学力学与工程学院辽宁阜新123000

随着煤炭开采向深部转移,巷道冒顶、底臌和两帮移进等软岩大变形问题层出不穷,对煤矿安全生产带来了严峻的挑战。目前,兼具连续方法和非连续方法优势的连续-非连续方法正在快速发展,然而,基于连续-非连续方法的蠕变研究尚少见报道。为... 详细信息

随着煤炭开采向深部转移,巷道冒顶、底臌和两帮移进等软岩大变形问题层出不穷,对煤矿安全生产带来了严峻的挑战。目前,兼具连续方法和非连续方法优势的连续-非连续方法正在快速发展,然而,基于连续-非连续方法的蠕变研究尚少见报道。为了模拟蠕变剪裂现象,以岩石发生蠕变破坏时的应变位于三轴压缩应力-应变曲线峰后区域内这一试验现象为基本依据,在自主开发的拉格朗日元与离散元耦合连续-非连续方法中,考虑了单元的黏弹性,发展了能模拟界面黏塑性的蠕变剪裂模型,并引入了蠕变剪裂判据。单轴压缩岩样的蠕变曲线计算结果与试验结果基本相符,蠕变剪裂开始稍后,岩样即进入加速蠕变阶段,这表明所提出的方法具有模拟加速蠕变的潜力。针对软岩巷道的计算表明,在深部围岩的推挤作用下,离散块体涌向巷道,导致巷道断面急剧缩小,在宏观上表现为大变形,巷道竖直方向收缩率可达58.8%。从单元的黏弹性和界面(虚拟裂纹面)的黏塑性两方面,丰富了软岩巷道大变形机制,即介质的黏弹性小变形、块体的大位移及之间的空隙以及界面的黏塑性变形共同作用。巷道围岩宏观上的大变形无须采用复杂大变形理论即可描述。

关键词：软岩蠕变大变形巷道围岩连续-非连续方法黏弹性剪裂

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Pluriclosed Manifolds with Constant Holomorphic Sectional Curvature

引用

Acta Mathematica Sinica,English Series 2022年第6期38卷 1094-1104页

作者： pei pei RAO fang Yang ZHENG School of Mathematical Sciences Chongqing Normal UniversityChongqing 401331P.R.China

A long-standing conjecture in complex geometry says that a compact Hermitian manifold with constant holomorphic sectional curvature must be Kèahler when the constant is non-zero and must be Chern flat when the constant is *** conjecture is known in complex dimension 2 by the work of Balas-Gauduchon in 1985(when the constant is zero or negative)and by Apostolov±Davidov±Muskarov in 1996(when the constant is positive).For higher dimensions,the conjecture is still largely *** this article,we restrict ourselves to pluriclosed manifolds,and confirm the conjecture for the special case of Strominger Kèahler-like manifolds,namely,for Hermitian manifolds whose Strominger connection(also known as Bismut connection)obeys all the Kaèhler symmetries.

关键词： Pluriclosed manifold Hermitian manifold Strominger connection holomorphic sectional curvature

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Qinling Faunal Region-The Third Ordovician Faunal Region:International Correlation

引用

Acta Geologica Sinica(English Edition) 2000年第2期74卷 137-142页

作者： pei fang Regional Geological Survey Party Henan Bureau of Geology and Mineral Exploration and DevelopmentPingdingshan 467021Henan

The Ordovician conodont faunal provinces were previously divided into the Midcontinent and Atlantic Faunal Regions situated respectively in low and high latitudes, where warm- and cold-water type conodont faunas flourished respectively. According to the international correlation this paper proposes the third Ordovician conodont faunal region—Qinling Faunal Region, in which cold-water conodont faunas were well developed in the Early to middle Middle Ordovician and warm-water conodont faunas were well developed in the late Middle and Late Ordovician, indicating that the Qinling Region was situated in high latitudes earlier and in low latitudes later. The origin was only due to plate movement. In the Qinling Region the time interval of the change of the conodont fauna from the cold- to warm-water type was 4 Ma (from 474 to 470 Ma), during which the fauna geographically spanned 40° of latitudes, with a movement velocity of nearly 1.12 m/a, indicating that the high-latitude plates were divorced and reduced in the late Middle Ordovician, while the low-latitude plates were converged and accreted. According to the features of the conodont faunas, the Qinling Faunal Region can be divided into the North Tarim, Wudang, Scandic and Pingliang provinces.

关键词： Midcontinent Faunal Region Altanic Faunal Region Qingling Faunal Region plate movement

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Thermodynamic performance assessment of vacuum membrane-based dehumidification and air carrying energy radiant air-conditioning system(VMD-ACERS)

引用

Chinese Journal of Chemical Engineering 2021年第6期34卷 217-227页

作者： Liang Chun Guangcai Gong Xi fang pei Peng Key Laboratory of Building Safety and Energy Efficiency Ministry of Education College of Civil Engineering Hunan UniversityChangsha 410082China

Temperature and humidity independent control(THIC)air-conditioning system is a promising *** this work,a novel temperature and humidity independent control(THIC)system is proposed,namely VMD-ACERS,which integrates vacuum membrane-based dehumidification and air carrying energy radiant air-conditioning *** work establishes a novel coefficient of performance(COP)model of *** main parameters affecting the COP of conventional fan coil unit cooling system(FCUCS)and VMD-ACERS are *** performance of FCUCS and VMD-ACERS are compared,and the energy-saving potential of VMD-ACERS is *** indicate that,for FCUCS,the importance ranking of parameters is basically ***,for VMD-ACERS,the importance ranking will be affected by FCU and *** most important parameters of VMD-ACERS are condensation temperature and permeate side *** the contrary,superheating,subcooling are relatively less important *** VMD-ACERS,it is not necessary to pursue the membrane with very high selectivity,because the selectivity of membrane would also be a less important parameter when it reaches *** COP of VMD-ACERS is higher than that of FCUCS when the permeate side pressure is higher than 8 k *** VMD-ACERS solves two technical problems about power-saving and thermal comfort of conventional THIC,and can extend the application of THIC air-conditioning system.

关键词： Fan coil unit cooling system Temperature and humidity independent control ACERS Vacuum membrane-based dehumidification COP

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

质子累积辐照效应对CMOS图像传感器饱和输出的影响

引用

物理学报 2025年第2期74卷 137-148页

作者：彭治钢白豪杰刘方李洋何欢李培贺朝会李永宏西安交通大学核科学与技术学院西安710049

本文通过辐照实验和TCAD仿真,研究了质子累积辐照导致四晶体管钳位光电二极管(4T PPD)CMOS图像传感器的饱和输出变化机理.实验采用的质子能量为12 MeV和60 MeV,最高质子注量为2×10^(12)cm^(-2).实验结果表明:12 MeV和60 MeV质子最高注... 详细信息

本文通过辐照实验和TCAD仿真,研究了质子累积辐照导致四晶体管钳位光电二极管(4T PPD)CMOS图像传感器的饱和输出变化机理.实验采用的质子能量为12 MeV和60 MeV,最高质子注量为2×10^(12)cm^(-2).实验结果表明:12 MeV和60 MeV质子最高注量辐照后分别导致转换增益增大8.2%和7.3%,满阱容量分别减小7.3%和3.8%.饱和输出在12 MeV质子辐照下变化趋势不显著,在60 MeV质子辐照下增大3%.在TCAD仿真中,建立了单个三维4T PPD像元模型,开展了质子累积辐照效应仿真来分析损伤机理.仿真结果表明像元饱和输出的变化由满阱容量、复位晶体管的物理特性和浮置扩散区的电容决定,但它们具有不同的影响.具体而言,满阱容量的降低导致饱和输出减小,而复位晶体管的辐照效应导致饱和输出增大.辐照导致浮置扩散区的电容减小,从而使转换增益增大,进而饱和输出增大.上述工作较为全面地揭示和分析了辐照后饱和输出的变化机理,研究成果对CMOS图像传感器的辐射损伤分析具有一定的指导意义.

关键词： CMOS图像传感器总剂量效应饱和输出满阱容量转换增益

来源：

维普期刊数据库

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：