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综合管廊的区间设计 预览
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作者 强健 王恒栋 祁峰 《隧道建设(中英文)》 北大核心 2019年第9期1480-1485,共6页
为进一步完善城市地下综合管廊工程设计理论,提高综合管廊工程设计的科学性与合理性,基于大量综合管廊工程设计实践,提出将“区间”概念应用于综合管廊工程的总体设计。通过对综合管廊功能需求和入廊管线技术要求的分析,给出综合管廊各... 为进一步完善城市地下综合管廊工程设计理论,提高综合管廊工程设计的科学性与合理性,基于大量综合管廊工程设计实践,提出将“区间”概念应用于综合管廊工程的总体设计。通过对综合管廊功能需求和入廊管线技术要求的分析,给出综合管廊各类“功能区间”的定义、特征;通过进一步分析综合管廊各类功能区间的相互关系和重要性,提出通过功能区间构建具备复合功能属性、可复制的“单元区间”,再通过单元区间的复制串联实现综合管廊总体设计的系统布置方法。最后,提出以“单元区间”为核心理念的综合管廊“区间设计”的定义和一般方法,以期为综合管廊工程系统布置提供一种新的设计思路。 展开更多
关键词 综合管廊 区间 功能区间 单元区间 区间设计
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T形截面振子的驰振特性试验研究 预览
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作者 燕翔 练继建 +3 位作者 刘昉 任泉超 张军 邵楠 《振动工程学报》 EI CSCD 北大核心 2019年第3期431-438,共8页
T形振子的流致振动响应表现出了"非自限制"特性,随着流速的增大出现驰振现象,振动增强,有利于能量利用.但T形振子在复杂环境条件及自身截面变化条件下的研究尚未开展.基于此,进行了T形振子的试验研究,旨在探索其流致振动完整... T形振子的流致振动响应表现出了"非自限制"特性,随着流速的增大出现驰振现象,振动增强,有利于能量利用.但T形振子在复杂环境条件及自身截面变化条件下的研究尚未开展.基于此,进行了T形振子的试验研究,旨在探索其流致振动完整响应规律及在不同截面高宽比下的响应差异,具体结论如下:与三棱柱振子类似,T形振子也存在硬、软驰振现象,阻尼比较大时,出现硬驰振现象,而阻尼比较小时出现软驰振现象;软驰振响应中,振子的驰振具有自激发特性,由涡激振动激发而成;硬驰振响应中,振子需外力才可激发驰振;随着截面高宽比的增大,振动响应逐渐由硬驰振转化为软驰振,且驰振分支中振幅与频率均有所降低. 展开更多
关键词 流致振动 涡激振动 T形截面 驰振 截面高宽比
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AutoCAD格式图件转换为MapGIS格式图件的方法 预览
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作者 张旭 《化工矿产地质》 CAS 2019年第1期46-49,共4页
AutoCAD格式图件保存为DXF的交换格式图件,利用section软件读取DXF文件,并分层保存,通过综合整饰,得到转换后未添加坐标系统的MapGIS格式图件,可利用MapGIS生成标准图框的方式,为转换后的图件添加坐标系统section和MapGIS两款软件配合使... AutoCAD格式图件保存为DXF的交换格式图件,利用section软件读取DXF文件,并分层保存,通过综合整饰,得到转换后未添加坐标系统的MapGIS格式图件,可利用MapGIS生成标准图框的方式,为转换后的图件添加坐标系统section和MapGIS两款软件配合使用,可将AutoCAD格式图件较好的、快速转换为MapGIS格式的图件。 展开更多
关键词 AUTOCAD MAPGIS SECTION 转换
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Unit 1 What’s the m atter?Section B 2a—2e教学设计及评析 预览
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作者 孙黎 张丽华 《黑龙江教育:中学版》 2019年第5期18-21,共4页
[本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级下册。]一、教材内容与分析本单元话题是健康与急救(Health and first aid).Section B是Section A主题的继续与延伸,由Section A侧重谈论疾病及不适转向对事故伤害、急... [本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级下册。]一、教材内容与分析本单元话题是健康与急救(Health and first aid).Section B是Section A主题的继续与延伸,由Section A侧重谈论疾病及不适转向对事故伤害、急救(first aid)的讨论;语言上,巩固Section A所学重点语言内容、词汇及表达,突出对步骤顺序的表达;技能上,侧重综合性的听、读、写的训练,尤其突出阅读. 展开更多
关键词 SECTION 意志品质 优良品质 珍惜生命 s the M atter?Section B 2a UNIT 1 What 教学设计
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美國專利訴訟綜述及最新發展(下)
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作者 Thomas L Jarvis Cyrus T Frelinghuysen +2 位作者 Randall R Rader 郝元 王維多 《中国专利与商标》 2019年第3期74-87,共14页
五、侵權行爲的最終救濟針對侵權行爲有兩種救濟:損害賠償金和禁令救濟。1.損害賠償金專利法規定,'損害賠償金應就侵權行爲充分賠償,在任何情况下不得少於侵權方使用發明應支付的合理的使用費'。81法院已經認可了計算合適的賠... 五、侵權行爲的最終救濟針對侵權行爲有兩種救濟:損害賠償金和禁令救濟。1.損害賠償金專利法規定,'損害賠償金應就侵權行爲充分賠償,在任何情况下不得少於侵權方使用發明應支付的合理的使用費'。81法院已經認可了計算合適的賠償金的多個依據,其中利潤損失和合理的使用費是最常見的兩個依據。 展开更多
关键词 PRO SECTION
Section 在“矿山测绘”资源储量估算中的应用探讨 预览
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作者 刘川 《世界有色金属》 2019年第5期27-27,29共2页
“矿山测绘”能为测绘工程行业提供有效依据,结合矿山测量、采矿企业的技术标准等,可以为地下工程行业、隧道工程提供有效指导,促使其工作意义的发挥。对矿产资源储量进行估算,是“矿山测绘”以及整个测绘技术中最为关键的部分。尤其是... “矿山测绘”能为测绘工程行业提供有效依据,结合矿山测量、采矿企业的技术标准等,可以为地下工程行业、隧道工程提供有效指导,促使其工作意义的发挥。对矿产资源储量进行估算,是“矿山测绘”以及整个测绘技术中最为关键的部分。尤其是在现代科学技术水平逐渐提升下,Section成为矿产资源储量估算的主要手段。在本文中,具体探究Section在“矿山测绘”资源储量估算中的应用。 展开更多
关键词 SECTION “矿山测绘” 资源 储量 估算
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General explicit solutions of most economic sections and applications for trapezoidal and parabolic channels 预览
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作者 Yan-cheng Han Said MEasa Xue-ping Gao 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第5期1034-1042,共9页
A channel section that has minimum construction cost is known as the most economic section.Such a section has important implications for economic efficiency.However,the most economic section is a complex optimization ... A channel section that has minimum construction cost is known as the most economic section.Such a section has important implications for economic efficiency.However,the most economic section is a complex optimization model with nonlinear objective function and constraints that is difficult to use by ordinary engineers.A general simple formula for the most economic section has not been attempted.In this paper,the general differential equation for the most economic section is derived using Lagrange multiplier optimization method.A simple method to solve the most economic section is proposed that converted the optimization model into a general equation for the most economic section of any shape.By solving this equation,the dimensions of the most economic section are directly obtained.To illustrate,the direct formula for trapezoidal section is derived.To aid application in practice,a simple explicit iterative formula for trapezoidal sections is presented.The direct and explicit iterative formulas were validated.The proposed method is superior to the classical optimization method and as such represent a valuable tool for open channel design.To illustrate the versatility of the presented method,a direct formula for the parabolic section was also derived. 展开更多
关键词 Most economic section CHANNEL PARABOLIC EXPLICIT hydraulic section
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In-medium NN→NΔ cross section and its dependence on effective Lagrange parameters in isospin-asymmetric nuclear matter
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作者 崔莹 张英逊 李祝霞 《中国物理C:英文版》 SCIE CAS CSCD 2019年第2期115-124,共10页
The in-medium NN→N△ cross sections and its differential cross sections in isospin asymmetric nuclear medium are investigated in the framework of the one-boson exchange model by including isovector mesons, i.e., δan... The in-medium NN→N△ cross sections and its differential cross sections in isospin asymmetric nuclear medium are investigated in the framework of the one-boson exchange model by including isovector mesons, i.e., δand p mesons. Our results show that the in-medium NN→N△ cross sections are suppressed when the density increases, and the differential cross sections become isotropic with an increase in the density around the △ threshold energy. The isospin splitting on the medium correction factor, R =σNN→N△*/σNN→N△free is observed for different channels of NN→N△, especially around the threshold energy for all the effective Lagrangian parameters. By analyzing the selected effective Lagrangian parameters, our results show that the larger effective mass is, the weaker medium correction R is. 展开更多
关键词 in-medium NN→NΔcross SECTION isospin-asymmetric nuclear matter Lagrangian PARAMETERS differential CROSS SECTION
Non-adiabatic quantum dynamical studies of Na(3p) + HD(v = 1, j5) = 0)→NaH/NaD + D/H reaction
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作者 温月佩 布仁巴雅尔 陈茂笃 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期169-175,共7页
Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-depende... Non-adiabatic dynamical calculations are carried out for the Na(3 p)+HD(ν = 1, j = 0)→NaH/NaD+D/H reaction on the diabatic potential energy surfaces of Wang et al.(Sci. Rep. 2018, 8, 17960) by using the time-dependent wave packet method. The state-to-state integral cross sections and differential cross sections of two reaction channels(NaH/NaD+D/H)are calculated for collision energy up to 0.4 eV. The cross section branching ratio indicates that the dominant reaction channel changes from NaD+H to NaH+D when the collision energy is larger than 0.227 eV. The products from two reaction channels both prefer to form in vibrationally cold but rotationally hot states, and they both tend to forward scattering. 展开更多
关键词 TIME-DEPENDENT wave packet method NON-ADIABATIC REACTION integral CROSS SECTION differential CROSS SECTION
Unit 7 Will people have robots?Section B 2a-2e教学设计及评析 预览
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作者 孙黎 《黑龙江教育:中学版》 2019年第9期14-16,共3页
[本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级上册。]一、教材内容分析本单元的话题主要是谈论未来生活(Life in the future),本节Section B部分的阅读课将Section A部分'谈论未来世界'的话题拓展到'... [本课选自人教版义务教育课程标准实验教科书《英语》(新目标)八年级上册。]一、教材内容分析本单元的话题主要是谈论未来生活(Life in the future),本节Section B部分的阅读课将Section A部分'谈论未来世界'的话题拓展到'谈论个人的未来生活'。2a-2e是一个整体的阅读板块,该单元阅读语篇谈论的是对未来机器人发展的不同预测。 展开更多
关键词 snake SECTION UNIT 7 WILL PEOPLE HAVE robots?Section B 2a-2e 教学设计
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多波束测深系统在水下抛石验收中的应用 预览
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作者 李维奇 王小龙 卢禹成 《港工技术》 2019年第1期108-111,共4页
本文利用多波束测深系统对长江口岸直水道整治工程进行水下抛石验收,利用多波束技术覆盖整个施工区平面的全覆盖测量方式,通过水深格网结合三维模式展示,真实反映了抛石增厚值、坝顶高度、宽度、及边坡比等指标,完全反映了施工区抛石效... 本文利用多波束测深系统对长江口岸直水道整治工程进行水下抛石验收,利用多波束技术覆盖整个施工区平面的全覆盖测量方式,通过水深格网结合三维模式展示,真实反映了抛石增厚值、坝顶高度、宽度、及边坡比等指标,完全反映了施工区抛石效果,使结果具有唯一性。本文技术成果方便了抛石工艺的优化,为水下抛石重大工程的验收提供了一个新的思路,可以极大提高作业效率以及节约成本,具有广泛的应用价值。 展开更多
关键词 多波束测深系统 断面 格网 三维 水道整治
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Experimental study of large-amplitude standing-wave field obtained in a standing-wave tube with uniform cross section
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作者 MIN Qi HE Wanquan +2 位作者 WANG Quanbiao GE Shuping WANG Shengyu 《声学学报:英文版》 CSCD 2019年第3期353-368,共16页
A large-amplitude standing-wave field of 182.1 dB is obtained under the excitation at the resonant frequency of the lst-order peak of the sound pressure transfer function in an improved standing-wave tube experimental... A large-amplitude standing-wave field of 182.1 dB is obtained under the excitation at the resonant frequency of the lst-order peak of the sound pressure transfer function in an improved standing-wave tube experimental system,and saturation of harmonics and waveform distortion are investigated experimentally for the large-amplitude standing-wave fields obtained under the excitations at the resonant frequencies of the 1 st-to the 5 th-order peaks.The results show that although the sound pressure level has reached 182.1 dB under the excitation at the resonant frequency of the 1 st-order peak,the waveform distortion is the minimum and the harmonic saturation is not observed.However,the large-amplitude standing-wave field excited at the resonant frequency of the 3 rd-order peak exhibits the trend of the harmonic saturation.Comparison of the large-amplitude standing-wave fields obtained under the excitations at valley resonant frequencies shows that the standing-wave field excited at the resonant frequency of the 1 st-order valley has the largest SPL,but also has the largest waveform distortion.Under the same source-driving voltage,the standing-wave field excited at the resonant frequency of the 1 st-order peak always has greater SPL than the standing-wave field excited at the resonant frequency of the 1 st-order valley.Hence,to obtain a large-amplitude standing-wave field,it’s better to excite at the resonant frequency of the 1 st-order peak of the SPTF by using loudspeaker in a standing-wave tube with uniform cross section. 展开更多
关键词 domain SPL Experimental study of LARGE-AMPLITUDE STANDING-WAVE field obtained in a STANDING-WAVE TUBE with UNIFORM cross section
Developmental characteristics and geological significance of the bentonite in the Upper Ordovician Wufeng–Lower Silurian Longmaxi Formation in eastern Sichuan Basin,SW China 预览
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作者 WANG Yuman LI Xinjing +4 位作者 WANG Hao JIANG Shan CHEN Bo MA Jie DAI Bing 《石油勘探与开发:英文版》 2019年第4期687-700,共14页
Based on the Qiliao section of the Upper Ordovician Wufeng Formation – Lower Silurian Longmaxi Formation in Shizhu, Chongqing city, the development characteristics of bentonite in eastern Sichuan Basin was examined s... Based on the Qiliao section of the Upper Ordovician Wufeng Formation – Lower Silurian Longmaxi Formation in Shizhu, Chongqing city, the development characteristics of bentonite in eastern Sichuan Basin was examined systematically, and its geological significance and scientific value were analyzed. The main understandings are as follows:(1) Six bentonite dense layers were found in the Qiliao section, mainly occurring in 6 graptolitic belts of the Katian, Rhuddanian and Aeronian. Most of the bentonite dense layers showed obvious increase in clay, peak response of GR curve, and indistinct relationship between volcanic ash and total organic carbon(TOC).(2) The bentonite dense layers of Longmaxi Formation were widely distributed in eastern Sichuan Basin and its periphery, and generally showed GR peak, which can be an important reference interface for dividing the bottom boundary of the Coronograptus cyphus belt and the top boundary of the Rhuddanian in eastern Sichuan Basin and western Hubei province.(3) Taking the bentonite dense layers as the stratification basis of the Rhuddanian and Aeronian, it was determined that the sediment thickness of the Rhuddanian in the eastern Sichuan depression was generally 10–40 m, but only the upper part of the Coronograptus cyphus belt was deposited in the hinderland of Yichang Uplift, and the sedimentary thickness was only 3–7 m.(4) In the hinderland of the Yichang Uplift, at least five and a half graptolitic belts were missing in Wufeng Formation – Rhuddanian, and the deposition time of Rhuddanian was less than 0.4 Ma.(5) The bentonite dense layers were important sedimentary responses to the strong deflection of the Yangtze basin at the turn of the Ordovician–Silurian, which suggested that four tectonic activity periods existed in the eastern Sichuan depression, including the early stage of the depression, the middle-late stage of the depression, the early stage of the foreland flexure and the development stage of the foreland flexure. The high-quality shale was mainly d 展开更多
关键词 Sichuan Basin Qiliao Section Lower SILURIAN Longmaxi Formation BENTONITE Yichang UPLIFT depression behind the UPLIFT organic-rich shale
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CFD simulation of the effects of a suspension section on the hydrodynamics of a circulating fluidized bed
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作者 Cenfan Liu Nan Zhang Wei Wang 《中国颗粒学报:英文版》 SCIE EI CAS CSCD 2019年第2期1-8,共8页
Gas-solid two-phase flow in a circulating fluidized bed (CFB) is affected by operating conditions (e.g., superficial gas velocity, solids inventory), material properties and geometric factors, such as the entry and ex... Gas-solid two-phase flow in a circulating fluidized bed (CFB) is affected by operating conditions (e.g., superficial gas velocity, solids inventory), material properties and geometric factors, such as the entry and exit configuration. In particular, the suspension section, which is located between the riser bottom and the solids recycle inlet, affects the hydrodynamics in the riser significantly. However, the suspension section has received less attention compared with other geometric factors. Most computational fluid dynamics (CFD) simulations, especially two-dimensional simulations do not take this factor into account. We performed three-dimensional, full-loop CFD simulations with a drag coefficient that was determined by the energy-minimization multi-scale model, and investigated the flow behavior of two CFBs with different suspension-section lengths. The simulation resuits revealed that the axial profiles of voidage in the riser with a longer suspension section are more likely S-shaped, whereas those with shorter suspension sections decay exponentially. The dependences of solids flux on solids inventory differ in the two CFBs. A shorter suspension section may result in a smooth transition from dilute to dense transport without intermediate accumulative choki-ng, whereas a Ion ger suspe nsion section may lead to a choking transition. These simulation results are qualitatively consistent with the flow behaviors described in literature. 展开更多
关键词 Computational fluid dynamics FLUIDIZATION MESO-SCALE Energy-minimization multi-scale SUSPENSION SECTION
“Exploring petroleum inside source kitchen”: Connotation and prospects of source rock oil and gas 预览
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作者 YANG Zhi ZOU Caineng 《石油勘探与开发:英文版》 2019年第1期181-193,共13页
Based on the transitional background of the global energy structure, exploration and development of unconventional oil and gas, and investigation of key basins, the unconventional oil and gas resources are divided int... Based on the transitional background of the global energy structure, exploration and development of unconventional oil and gas, and investigation of key basins, the unconventional oil and gas resources are divided into three types: source rock oil and gas, tight oil and gas, and retention and accumulated oil and gas. Source rock oil and gas resources are the global strategic supplies of oil and gas, the key resource components in the second 150-year life cycle of the future petroleum industry, and the primary targets for “exploring petroleum inside source kitchen”. The geological connotation of source rock oil and gas was proposed, and the models of source rock oil and gas generation, expulsion and accumulation were built, and five source rock oil and gas generation sections were identified, which may determine the actual resource potential under available technical conditions. The formation mechanism of the “sweet sections” was investigated, that is, shale oil is mainly accumulated in the shale section that is close to the oil generation section and has higher porosity and permeability, while the “sweet sections” of coal-bed methane(CBM) and shale gas have self-contained source and reservoir and they are absorbed in coal seams or retained in the organic-rich black shale section, so evaluation and selection of good 'sweet areas(sections)' is the key to “exploring petroleum inside source kitchen”. Source rock oil and gas resources have a great potential and will experience a substantial growth for over ten world-class large “coexistence basins” of conventional-unconventional oil and gas in the future following North America, and also will be the primary contributor to oil stable development and the growth point of natural gas production in China, with expected contribution of 15% and 30% to oil and gas, respectively, in 2030. Challenges in source rock oil and gas development should be paid more attention to, theoretical innovation is strongly recommended, and a development pilot zone can be est 展开更多
关键词 SOURCE rock OIL and GAS SHALE GAS SHALE OIL coal-bed methane SWEET section SWEET area SOURCE control theory man-made OIL and GAS reservoir UNCONVENTIONAL OIL and GAS revolution large“coexistence basins”of conventional-unconventional OIL and GAS
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岩质高陡边坡关键剖面稳定性分析 预览
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作者 张宽 成启航 +1 位作者 丁选星 汪少杰 《山东农业大学学报:自然科学版》 北大核心 2019年第5期821-824,共4页
小江口隧道边坡是灰岩夹泥灰岩的岩质高陡边坡,陡崖处存在两处由多组不规则卸荷裂隙围限出的危岩体,危及拟建隧道及桥梁的安全。为确保隧道施工过程和运营的安全,以小江口隧道为原型,选取关键剖面评价局部危岩体的稳定性。研究表明:隧... 小江口隧道边坡是灰岩夹泥灰岩的岩质高陡边坡,陡崖处存在两处由多组不规则卸荷裂隙围限出的危岩体,危及拟建隧道及桥梁的安全。为确保隧道施工过程和运营的安全,以小江口隧道为原型,选取关键剖面评价局部危岩体的稳定性。研究表明:隧道出口岸坡与上游侧陡崖边坡的坡体应力状态相同,均呈现坡脚位置应力集中,陡坡面存在受拉区的高山峡谷应力分布特征,易在边坡底部出现剪切破坏以及高位陡岩发生崩塌落石等地质灾害。隧道出口段南侧陡崖的破坏模式为渐进式倾倒破坏,上游侧陡崖的破坏模式是错落式破坏。 展开更多
关键词 边坡 剖面 稳定性
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浅埋煤层综采工作面区段煤柱支承压力监测分析 预览
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作者 刘明 《山东煤炭科技》 2019年第9期81-82,88共3页
以四台矿8715综采面为工程背景,根据设计的煤柱相对应支承压力监测方案进行现场监测,结合煤柱对应支承压力的实测数据和松动圈钻孔电视探测仪的探测,分析了浅埋煤层条件下的综采面区段煤柱的塑性区范围和松动区范围。结果表明:14号煤层... 以四台矿8715综采面为工程背景,根据设计的煤柱相对应支承压力监测方案进行现场监测,结合煤柱对应支承压力的实测数据和松动圈钻孔电视探测仪的探测,分析了浅埋煤层条件下的综采面区段煤柱的塑性区范围和松动区范围。结果表明:14号煤层区段煤柱的塑性区宽度为4m,合理的煤柱尺寸为18m,原煤柱宽度20m,可优化减小2m。 展开更多
关键词 综采面 区段 煤柱 监测
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Geophysical criterion of pre-outburst coal outsqueezing from the face space into the working 预览
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作者 Alexander Shadrin Yuliya Diyuk 《矿业科学技术学报:英文版》 CSCD 2019年第3期499-506,共8页
The initial process of coal and gas sudden outburst is studied in the article when under the influence of rock and gas pressure the part of a coal seam layer(a coal section)is squeezed out from the mouth of the future... The initial process of coal and gas sudden outburst is studied in the article when under the influence of rock and gas pressure the part of a coal seam layer(a coal section)is squeezed out from the mouth of the future outburst cavity in a jump-like manner into the working.Geo-mechanical criterion for a part of a coal seam layer outsqueezing in the form of the relation of active(squeezing out)and passive(preventing the outsqueezing)forces is defined in the article.Based on it,the geophysical criterion is defined by expressing basic physical parameters through geo-physical ones:the current stress is defined by spectral-acoustic method through the ratio of high frequency and low-frequency components of an acoustic signal,which is generated into a face working space by the mining equipment operating in the face;in-situ gas pressure is defined by gas analytical method by the concentration of methane in the atmosphere of the working;the strength of the most broken coal layer is defined by a strength measuring device(a device for measuring the depth of a steal cone punched into the coal by a spring mechanism).This paper studies the influence of acoustic,strength and filtrating and collecting properties of a face working space on the limit value of an obtained geophysical criterion of pre-outburst squeezing of a coal‘‘plug”out of the mouth of the future outburst cavity into the working. 展开更多
关键词 Block-like structure CRITERION of a COAL section outsqueezing Spectral-acoustic method Stress condition COAL strength property IN-SITU GAS pressure Aero and GAS control equipment METHANE concentration
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π截面铝合金型材拉弯成形工艺数值模拟研究
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作者 卜晓珍 翟华 +2 位作者 周丽华 俞春生 赵坤民 《塑性工程学报》 CAS CSCD 北大核心 2019年第2期151-161,共11页
针对A7075-T6型材结构件,利用ABAQUS软件建立π型截面型材拉弯成形有限元模型,对该铝合金型材结构件拉弯成形进行数值模拟,并分析预拉量、补拉量、弯曲半径及摩擦系数的变化对回弹的影响。结果表明:预拉量、补拉量、弯曲半径和摩系数都... 针对A7075-T6型材结构件,利用ABAQUS软件建立π型截面型材拉弯成形有限元模型,对该铝合金型材结构件拉弯成形进行数值模拟,并分析预拉量、补拉量、弯曲半径及摩擦系数的变化对回弹的影响。结果表明:预拉量、补拉量、弯曲半径和摩系数都会影响回弹量,在相对应的变化范围内,回弹随着预拉量、补拉量的增大有明显减小的趋势,而回弹量与弯曲半径和摩擦系数均呈正相关。其中对回弹量的变化影响较为明显的为拉伸量;当预拉量为1%,补拉量为2%,摩擦系数为0. 08,弯曲半径为200 mm时,回弹最小。 展开更多
关键词 铝合金型材 π截面 拉弯成形 回弹
Reaction mechanism of D + ND→N + D2 and its state-to-state quantum dynamics
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作者 许婷 赵娟 +1 位作者 王宪龙 孟庆田 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第2期173-178,共6页
The quantum state-to-state calculations of the D + ND→N + D2 reaction are performed on a potential energy surface of 4 A’’ state. The state-resolved integral and differential cross sections and product state distri... The quantum state-to-state calculations of the D + ND→N + D2 reaction are performed on a potential energy surface of 4 A’’ state. The state-resolved integral and differential cross sections and product state distributions are calculated and discussed. It is found that the rotational distribution, rather than the vibrational distribution, of the product has an obvious inversion. Due to the fact that it is a small-impact-parameter collision, its product D2 is mainly dominated by rebound mechanism, which can lead to backward scattering at low collision energy. As the collision energy increases, the forward scattering and sideward scattering begin to appear. In addition, the backward collision is also found to happen at high collision energy, through which we can know that both the rebound mechanism and stripping mechanism exist at high collision energy. 展开更多
关键词 state-to-state quantum dynamics TIME-DEPENDENT wave PACKET D+ND differential cross section
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