Elimination mechanism of coal and gas outburst based on geo‑dynamic system with stress–damage–seepage interactions

Coal and gas outburst is a complex dynamic disaster during coal underground mining.Revealing the disaster mechanism is of great signifcance for accurate prediction and prevention of coal and gas outburst.The geo-dynamic system of coal and gas outburst is proposed.The framework of geo-dynamic system is composed of gassy coal mass,geological dynamic environment and mining disturbance.Equations of stress–damage–seepage interaction for gassy coal mass is constructed to resolve the outburst elimination process by gas extraction with boreholes through layer in foor roadway.The results show the occurrence of outburst is divided into the evolution process of gestation,formation,development and termination of geo-dynamic system.The scale range of outburst occurrence is determined,which provides a spatial basis for the prevention and control of outburst.The formation criterion and instability criterion of coal and gas outburst are established.The formation criterion F1 is defned as the scale of the geo-dynamic system,and the instability criterion F2 is defned as the scale of the outburst geo-body.According to the geo-dynamic system,the elimination mechanism of coal and gas outburst—‘unloading+depressurization’is established,and the gas extraction by boreholes through layer in foor roadway for outburst elimination is given.For the research case,when the gas extraction is 120 days,the gas pressure of the coal seam is reduced to below 0.4 MPa,and the outburst danger is eliminated efectively.

A STUDY ON RECESSION MECHANISM AND REJUVENATION WAYS OF THENORTHEAST OLD INDUSTRIAL BASE

Using the theory of regional superiority of forming and developing Of the old industrial bases and theory of transfondng industrial structure, the paper analyses the recession characteristics, reasons and mechanism of the northest Old industrial base. On the basis of analysing and using the successful experience of other countries, the authors put forward the pattern, goal and way of transforming the northeast old industrial base, combined with the particular national conditions. The poper wants to make the theory and practice system of forming and developing of the world industrial bases more perfect, and provide some experience to promote the systematic development and speed up the industrialized course in the industrial ha of developing countries.

Kinematic Solution of Spherical Stephenson-Ⅲ Six-bar Mechanism

A closed-form solution can be obtained for kinematic analysis of spatial mechanisms by using analytical method.However,extra solutions would occur when solving the constraint equations of mechanism kinematics unless the constraint equations are established with a proper method and the solving approach is appropriate.In order to obtain a kinematic solution of the spherical Stephenson-III six-bar mechanism,spherical analytical theory is employed to construct the constraint equations.Firstly,the mechanism is divided into a four-bar loop and a two-bar unit.On the basis of the decomposition,vectors of the mechanism nodes are derived according to spherical analytical theory and the principle of coordinate transformation.Secondly,the structural constraint equations are constructed by applying cosine formula of spherical triangles to the top platform of the mechanism.Thirdly,the constraint equations are solved by using Bezout’ s elimination method for forward analysis and Sylvester’ s resultant elimination method for inverse kinematics respectively.By the aid of computer symbolic systems,Mathematica and Maple,symbolic closed-form solution of forward and inverse displacement analysis of spherical Stephenson-III six-bar mechanism are obtained.Finally,numerical examples of forward and inverse analysis are presented to illustrate the proposed approach.The results indicate that the constraint equations established with the proposed method are much simpler than those reported by previous literature,and can be readily eliminated and solved.

DFT Study of Oxygenated Organic Pollutants Catalyzed by Molybdenum Oxides: Comparison of Reaction Mechanisms of MoO_x + HCHO(x = 1, 2, 3)

The reaction mechanisms between formaldehyde and MoOx(x = 1, 2, 3) have been studied thoroughly in this paper. Five reaction pathways were found in three reactions(reactions Ⅰ to Ⅲ) through studying the mechanisms of MoOx(x = 1, 2, 3) catalyzing formaldehyde. Different products were obtained from three reactions. Of all three reactions, the barrier energy of Route ⅡA is the lowest(4.70 kcal/mol), which means in MoOx(x = 1, 2, 3), MoO2 has the best catalytic effect. Compared with other similar non-toxic treatments of formaldehyde, our barrier energy is the lowest. In this research, there was no good leaving group of the compound, so the mechanisms are addition reaction. We speculate that there must be an addition reaction to the more complex reactions to molybdenum oxides and aldehydes. As a chemical reagent for removing formaldehyde, it only absorbs formaldehyde and does not emit other toxic substances outward. Molybdenum oxides retain its original structures of the final products, which means it has excellent stability in the reaction of MoOx(x = 1, 2, 3) + HCHO. The mechanisms of all three reactions are addition reactions, but they are entirely different. As the number of oxygen atoms increases, the reaction mechanisms become simpler.

Conversion of 3,4-Dihydroxypyrrolidine-2,5-Dione to Maleimide through Tosylation and Mechanism Study by DFT

Pyrrolidine-2,5-dione and maleimide are important scaffolds of many organic substances, and their derivatives are now attracting more and more interests from researchers in organic synthesis, medicinal chemistry, and drug development. Tosyloxy (-OTs) group is an important functional group widely used in organic synthesis, because it can be readily prepared from alcohols and is an excellent leaving group. However, surprisingly, substances bearing tosyloxy groups on pyrrolidine-2,5-dione or maleimide scaffolds are very rare. In this study, we discovered that, when treated with TsCl/Et3N,?trans-3,4-dihydroxypyrrolidine-2,5- dione will eliminate a TsOH molecule to form monotosyloxymaleimide. Thermodynamic and kinetic factors affecting this reaction were investigated by theoretical computation using density functional theory (DFT), and the possible reaction mechanism was proposed based on the computation results. Our results showed that tosylates of trans -3,4-dihydroxypyrrolidine- 2,5-dione, either monotosylate or ditosylate, are thermodynamically instable and may spontaneously convert to maleimides. This knowledge could be useful in understanding the properties of pyrrolidine-2,5-diones and maleimides, as well as the related organic synthesis.

SUB-NANOMETER POLISHING OF MAGNETIC RIGID DISK HEADS TO AVOID POLE TIP RECESSION

For the purpose of solving the problem that too large pole tip recession （PTR） is produced in magnetic rigid disk heads by mechanical polishing, a chemical mechanical nano-grinding experiment is performed by using a float-piece polisher with a tin plate to achieve a more plane and smoother surface. A basal solution, addition agents and a range of pH value are suitably selected to find a kind of slurry, with which the PTR can be controlled on sub-nanometer scale and the giant magnetic resistance （GMR） corrosion and electrostatic damage （ESD） can be avoided. Moreover, the cause that TiC protrudes from the substrate surface of the heads is studied. The appropriate shape and size of diamond abrasive are selected according to the chemical activation of A1203 and TiC in the same slurry. In this way, the chemical and mechanical interactions are optimized and the optimal surface that has small PTR and TiC asperity is achieved. Ultimatily, the chemical mechanical nano-grinding in combination with mechanical nano-grinding is adopted. Sub-nanometer PTR is achieved and the TiC asperity is eliminated by the chemical mechanical nano-grinding with large size ofmonocrystalline followed by mechanical nano-grinding with smalle polycrystalline diamonds.

Theoretical studies on the mechanism of α-hydroxy-acid gas-phase elimination process and its substituent effect

The α-hydroxy-acid gas-phase elimination process has been studied theoretically by HF/3-21G.The calculated results can be summed up as follows:(1) The elimination process is a stepwise reaction.In the first step,a 3-membered ring intermediate is formed via a 5-membered ring transition state;while the product is formed in the second step via a 3-membered ring transition state.(2) The obtained results of the substituent effect show that the increase of electronic donation of the alkyl groups is favorable for the reaction.Other substituents which show the electron-withdrawing inductive effect (e.g.-Cl,-CN,-CF3) are unfavorable for this process.

论有效清除腐败存量的刑法机制

立足于反腐败斗争的新形势,有必要在现行法律框架下寻求有效清除腐败存量的法律机制。存量腐败的清除在很大程度上意味着刑罚的消灭,故可结合我国刑法中的追诉时效和赦免这两种刑罚消灭制度具体展开。追诉时效是清除腐败犯罪存量的常规机制,但可能时间长、代价大。赦免是清除腐败犯罪存量的非常规机制。可由全国人大适时制定专门决定,设立统一的全国性廉政账户,对党的二十大之前的存量腐败犯罪予以有条件赦免,并在涤清巨大腐败存量的同时,确立公职人员家庭财产和重点事项申报与公示制度等遏制腐败的“治本”之策。

基于NSGA-III算法求解柔性作业车间调度问题

针对多目标柔性作业车间调度问题,提出一种改进NSGA-Ⅲ算法,以完工时间、机器总负荷、瓶颈机器负荷为目标建立调度模型。首先,为提高种群的多样性,提出一种基于惩罚的边界相交距离定义关联操作中种群个体与参考向量之间的距离;其次,为提高环境选择的计算效率,利用基于惩罚的边界相交距离消除机制来保护个体,降低了个体保护策略的计算成本;最后,为避免种群陷入局部最优,在遗传算子中采用一种改进的变异策略。运用两个评价指标与NSGA-Ⅲ算法进行比较,其收敛性与多样性均由于NSGA-Ⅲ算法。同时在4个Kacem算例上进行测试得出改进NSGA-Ⅲ算法解的质量较高,最后通过实际的生产实例证明改进的NSGA-Ⅲ算法优于或等同于现存在的方法,也证明了该方法在解决多目标柔性作业车间调度难题上的可操作性。

绿色人力资源管理“末位淘汰”考核机制探析

“末位淘汰制”是人力资源管理中绩效管理的一种考核方式。对“末位淘汰制”的现有研究大多从是否符合法律法规的角度展开,而基于绿色人力资源管理角度的研究基本没有。文章以绿色人力资源管理理念为基础,构建“末位淘汰”考核机制,设计了“能勤绩”三个考核指标,旨在为企业采用“末位淘汰”手段进行绩效管理时,既不违规违法,又能调动员工的工作积极性,从而打造充满朝气活力、和谐健康发展的企业。

领导干部“能上不能下”制度困境的形成机理与破解之道

本文以83名领导干部的访谈内容为研究样本,运用扎根理论,识别出影响领导干部“能上不能下”的因素主要包含实施主体、实施对象、制度本身和运行环境四个维度。具体来说:实施主体在推进干部能上能下过程中出现执行乏力问题;实施对象受到趋利避害的个人偏好的驱动和影响;制度本身存在着操作性障碍;蕴含于特定政治生态环境中的消极因素也成为领导干部“能下”的阻力。相应地提出破解领导干部“能上不能下”制度困境的因应之策:着力提高组工干部队伍的专业化能力,解决好实施主体执行乏力问题;进一步提升广大领导干部的担当精神与大局意识,解决实施对象利己偏好的问题;完善长效化协同化的制度体系,解决制度操作性障碍的问题;不断引导全社会形成包容开放的文化氛围,解决运行环境压力渗透的问题。

回风井口成雾原因及除雾技术研究

针对井口雾气污染工作环境,危害工人身体健康,造成井下设备及构筑物严重损害等问题,以云南某铅锌矿为工程背景,通过理论分析、室内试验、数值模拟及现场工业试验等方法,分析了温度、相对湿度及回风量对井口成雾析水量的影响规律,提出了Ⅰ级+Ⅱ级折流板除雾器除雾方法。研究结果表明:风流及温度均能引起空气中水蒸气析出,在严冬风流上行越高,雾气越大;井口成雾析水量随回风量增加呈线性增加,随温度及相对湿度增加呈线性降低;温度、相对湿度及回风量平均每下降1℃,1%,1 m3/s,井口成雾析水量分别增加84、17.2、5 g/s,说明温度是井口成雾析水量的主要影响因素,各因素对井口成雾析水量影响由大到小排序为温度>相对湿度>回风量。采用Ⅰ级+Ⅱ级折流板除雾器除雾时,回风井巷道内压降为300 Pa,表明气流通过除雾器时会产生压力损失。与加入喷淋试验相比,不加喷淋的双级除雾器除雾方法经济成本显著降低,并且现场除雾效果更显著,因而推荐该矿采用不加喷淋的Ⅰ级+Ⅱ级折流板除雾器除雾方法。

小檗碱消除ESBLs大肠杆菌耐药性的研究

为了研究小檗碱消除超广谱β-内酰胺酶(ESBLs)大肠杆菌耐药性的效果,试验以3株ESBLs大肠杆菌作为研究对象,采用二倍稀释法测定小檗碱作用3株ESBLs大肠杆菌前后的MIC变化,然后采用琼脂糖凝胶电泳、ELISA法和实时荧光定量PCR方法分别检测小檗碱作用后大肠杆菌R质粒、ESBLs活性、生物被膜形成及外排系统AcrA mRNA、AcrB mRNA转录水平的变化。结果表明:3株ESBLs大肠杆菌对小檗碱的MIC均为2.00 mg/mL;经小檗碱作用后有2株ESBLs大肠杆菌对头孢噻肟的MIC从32.00 mg/mL降至8.00 mg/mL,有1株ESBLs大肠杆菌对头孢噻肟的MIC从32.00 mg/mL降至16.00 mg/mL。经小檗碱作用后有2株ESBLs大肠杆菌质粒条带消失2条,有1株ESBLs大肠杆菌质粒条带消失1条;3株ESBLs大肠杆菌的ESBLs活性均极显著降低(P<0.01),碱性磷酸酶活性均极显著升高(P<0.01);3株ESBLs大肠杆菌外排系统AcrA mRNA转录水平极显著降低(P<0.01),2株ESBLs大肠杆菌外排系统AcrB mRNA转录水平显著降低(P<0.05)。说明小檗碱对ESBLs大肠杆菌的4种耐药消除机制均具有良好的效果。

犯罪结构变化背景下的轻罪治理路径

随着刑事立法中大量轻罪罪名的出现及实践中大量轻罪案件的产生,我国犯罪结构发生深刻变化,如何治理轻罪相伴而生。有必要在明确轻罪范围的基础上,分别从实体和程序两个层面构建轻罪治理的具体路径。实体层面上,要明确出罪标准的适用,从罚金刑配置的合理性和缓刑配置的精准性两方面推动完善刑罚制裁体系,同时以成年人轻罪记录封存为基础阶梯式探索轻罪前科消灭。程序层面上,一要建立轻罪治理程序分流机制,同时慎用羁押性强制措施,对未判实刑或依法相对不诉的轻罪案件,充分发挥社区矫正作用;二要实现轻罪案件快速办理,建立完善轻罪案件侦捕诉联动与监督机制和轻罪案件协商机制,搭建从侦查到起诉再到判决执行的全流程、全方位轻罪治理体系。

适用于配电网无功优化的混合鱼群算法

人工鱼群算法同传统群智能算法一样,由于基础种群的随机性以及寻优路线的不确定性等原因可能导致算法寻不到最优解。为解决以上问题,利用混沌变换序列生成遍布更加均匀的初始值;采用自适应的视野与步长动态改变搜索范围;引入改进的生物“进化”机制,利用当代和精英个体的基因来对鱼群进行淘汰,加快收敛速度。将该混合算法用于IEEE33节点系统配电网的无功优化中,结果表明改进的算法更易跳出局部最优,且收敛速度较快,收敛性能较好,提高了寻优效率。

基于“瘀去-新生-骨合”理论研究富血小板血浆联合中药治疗股骨头坏死作用机制

非创伤性股骨头坏死(ONFH)是一种由于血供受损导致股骨头坏死、塌陷的骨科疑难性疾病。以辨证论治为基础,运用化痰祛瘀中药内服治疗早期ONFH,往往能取得较好的疗效。此外,富血小板血浆(PRP)含有多种生长因子,具有强大的再生能力,在ONFH治疗中呈现巨大潜力。“瘀去-新生-骨合”理论是中医骨伤科关于骨修复的重要理论,其原本用于描述骨折愈合的持续、渐进过程,而股骨头坏死的血供破坏,必有血瘀,整个股骨头坏死修复过程需要良好的血供支持,瘀血不去,新血不生,新生则骨合,这与骨折修复的过程不谋而合,因此,本文将基于“瘀去-新生-骨合”理论,探讨PRP联合化痰祛瘀中药治疗早期非创伤性股骨头坏死的作用机制,为临床治疗本病提供一定的理论参考。

加入淘汰机制的改进麻雀搜索算法

传统麻雀算法(sparrow search algorithm,SSA)具有搜索精度高、寻优能力强等优点,但同时也存在早熟收敛、迭代过程中容易陷入局部最优值等问题。针对这些问题,提出了一种加入Tent混沌映射和末位淘汰机制的麻雀搜索算法(sparrow search algorithm with tent,TESSA)。采用2N分段Tent混沌映射初始化种群位置。同时在算法迭代后期引入非线性末位淘汰机制,提高其收敛速度和精度。经过与其他4种群智能算法在6个基准函数上求解性能相比,TESSA的收敛速度、寻优精度、标准误差等性能指标有明显的优势。

Mechanical Properties of PPV Film in Thermal Elimination Process

This paper deals with the relationships between the structure of poly（p-phenylene vinylene）（PPV） film and treatment temperature and their mechanical properties.The chemical structures and aggregated structures of PPV precursor（PPVpre） and PPV treated at three node temperatures（125,155 and 230 ℃） were investigated by FTIR spectrometry and X-ray diffraction.The results show that the content of trans-conformation and the size of the crystalline domains increased with the increase of treatment temperature.The mechanical performances of the corresponding polymers were studied by nanoindentation.The elastic modulus and hardness of PPV films decreased with the increases of the content of trans-conformation and the size of the crystalline domains.These results suggest that the conformation and the size of the crystalline domains are able to induce the elastic modulus and hardness variation of PPV films.

基流研究综述

水资源是人类生产、生活不可或缺的自然资源,随着水资源危机的加剧和水环境质量的恶化,水资源短缺已成为世界倍受关注的资源环境问题之一。基流在水安全、粮食安全、非点源污染评价,水资源评价和调查,水资源配置、工农业供水和降雨-径流关系模拟中有着重要的应用。本文首先对基流的定义进行了概述,系统的综述了基流产生机制及其影响因素;对于各类退水方程,从退水方程所反映的流域特性出发,阐明其优缺点、适用条件及应用情况,并对退水方程的建立进行了讨论。方程的参数多,则退水过程拟合得好,简单的线性方程拟合的效果不如多个线性方程组合的效果好,这在一定程度上说明了流域含水层出流的非线性。综合了多种基流划分方法,认为模型模拟和水量平衡法具有较强理论基础,图形法具有较大主观性,其精度依赖于操作者对于河道和地下水联系的了解情况。最后,本文对基流退水方程的建立,以及基流方程拟合中要注意的问题也进行了总结。