Support design method for deep soft-rock tunnels in non-hydrostatic high in-situ stress field

Due to the long-term plate tectonic movements in southwestern China,the in-situ stress field in deep formations is complex.When passing through deep soft-rock mass under non-hydrostatic high in-situ stress field,tunnels will suffer serious asymmetric deformation.There is no available support design method for tunnels under such a situation in existing studies to clarify the support time and support stiffness.This study first analyzed the mechanical behavior of tunnels in non-hydrostatic in-situ stress field and derived the theoretical equations of the ground squeezing curve(GSC)and ground loosening curve(GLC).Then,based on the convergence confinement theory,the support design method of deep soft-rock tunnels under non-hydrostatic high in-situ stress field was established considering both squeezing and loosening pressures.In addition,this method can provide the clear support time and support stiffness of the second layer of initial support.The proposed design method was applied to the Wanhe tunnel of the China-Laos railway in China.Monitoring data indicated that the optimal support scheme had a good effect on controlling the tunnel deformation in non-hydrostatic high in-situ stress field.Field applications showed that the secondary lining could be constructed properly.

An Adaptive Sequential Replacement Method for Variable Selection in Linear Regression Analysis

With the rapid development of DNA technologies, high throughput genomic data have become a powerful leverage to locate desirable genetic loci associated with traits of importance in various crop species. However, current genetic association mapping analyses are focused on identifying individual QTLs. This study aimed to identify a set of QTLs or genetic markers, which can capture genetic variability for marker-assisted selection. Selecting a set with k loci that can maximize genetic variation out of high throughput genomic data is a challenging issue. In this study, we proposed an adaptive sequential replacement (ASR) method, which is considered a variant of the sequential replacement (SR) method. Through Monte Carlo simulation and comparing with four other selection methods: exhaustive, SR method, forward, and backward methods we found that the ASR method sustains consistent and repeatable results comparable to the exhaustive method with much reduced computational intensity.

Route Search Method for Railway Replacement Buses Adopting Ant Colony Optimization

In recent years, Japan, and especially rural areas have faced the growing problems of debt-ridden local railway lines along with the population decline and aging population. Therefore, it is best to consider the discontinuation of local railway lines and introduce replacement buses to secure the transportation methods of the local people especially in rural areas. Based on the above background, targeting local railway lines that may be discontinued in the near future, appropriate bus stops when provided with potential bus stops were selected, the present study proposed a method that introduces routes for railway replacement buses adopting ant colony optimization (ACO). The improved ACO was designed and developed based on the requirements set concerning the route length, number of turns, road width, accessibility of railway lines and zones without bus stops as well as the constraint conditions concerning the route length, number of turns and zones without bus stops. Original road network data were generated and processed adopting a geographic information systems (GIS), and these are used to search for the optimal route for railway replacement buses adopting the improved ACO concerning the 8 zones on the target railway line (JR Kakogawa line). By comparing the improved ACO with Dijkstra’s algorithm, its relevance was verified and areas needing further improvements were revealed.

A review of in-situ high-temperature characterizations for understanding the processes in metallurgical engineering

For the rational manipulation of the production quality of high-temperature metallurgical engineering,there are many challenges in understanding the processes involved because of the black box chemical/electrochemical reactors.To overcome this issue,various in-situ characterization methods have been recently developed to analyze the interactions between the composition,microstructure,and solid-liquid interface of high-temperature electrochemical electrodes and molten salts.In this review,recent progress of in-situ hightemperature characterization techniques is discussed to summarize the advances in understanding the processes in metallurgical engineering.In-situ high-temperature technologies and analytical methods mainly include synchrotron X-ray diffraction(s-XRD),laser scanning confocal microscopy,and X-ray computed microtomography(X-rayμ-CT),which are important platforms for analyzing the structure and morphology of the electrodes to reveal the complexity and variability of their interfaces.In addition,laser-induced breakdown spectroscopy,high-temperature Raman spectroscopy,and ultraviolet-visible absorption spectroscopy provide microscale characterizations of the composition and structure of molten salts.More importantly,the combination of X-rayμ-CT and s-XRD techniques enables the investigation of the chemical reaction mechanisms at the two-phase interface.Therefore,these in-situ methods are essential for analyzing the chemical/electrochemical kinetics of high-temperature reaction processes and establishing the theoretical principles for the efficient and stable operation of chemical/electrochemical metallurgical processes.

Stress initialization methods for dynamic numerical simulation of rock mass with high in-situ stress

In the context of deep rock engineering,the in-situ stress state is of major importance as it plays an important role in rock dynamic response behavior.Thus,stress initialization becomes crucial and is the first step for the dynamic response simulation of rock mass in a high in-situ stress field.In this paper,stress initialization methods,including their principles and operating procedures for reproducing steady in-situ stress state in LS-DYNA,are first introduced.Then the most popular four methods,i.e.,explicit dynamic relaxation(DR)method,implicit-explicit sequence method,Dynain file method and quasi-static method,are exemplified through a case analysis by using the RHT and plastic hardening rock material models to simulate rock blasting under in-situ stress condition.Based on the simulations,it is concluded that the stress initialization results obtained by implicit-explicit sequence method and dynain file method are closely related to the rock material model,and the explicit DR method has an obvious advantage in solution time when compared to other methods.Besides that,it is recommended to adopt two separate analyses for the whole numerical simulation of rock mass under the combined action of in-situ stress and dynamic disturbance.

Molecular Replacement Studies of Cucurmosin from Cucurbita Moschata:Structure Homology with Trichosanthin

High diffraction quality crystals of cucurmosin, a type I ribosome inactivating protein isolated from the sarcocarp of Cucurbita moschata (pumpkin), have been grown under newly optimised conditions. With in-house rotating anode X-ray source, these crystals diffract to 1.65 ?resolution which is much higher than that of the previously reported crystals that diffracted only to 3 ?resolution. The crystals belong to space group P212121 with cell parameters a = 41.5, b = 58.4 and c = 99.3 . Molecular replacement studies indicate that the cucurmosin structure is homologous to trichosanthin. The initial structural model has been obtained and the model fitting/ refinement is in progress.

Analysis on method for effective in-situ stress measurement in hot dry rock reservoir

With the rapid increase of energy demand and the increasingly highlighted environmental problems, clean, safe and widely distributed geothermal resources have become a hot spot for renewable resources development. The state of in-situ stress is a major control parameter for multiple links including well location, fracture inspiration and reservoir assessment, so how to determine the accurate state of in-situ stress in the deep thermal reservoir becomes a core problem drawing widely attention and urgent to be solved. Based on features of hot dry rock reservoir in terms of temperature and pressure and the comparison analysis, this article proposes the method of Anelastic Strain Recovery(ASR) as an effective method for determining the state of in-situ stress in the area with HDR resources distributed and explains the availability of ASR method by application examples.

Research of in-situ hydraulic test method by using double packer equipment

Double packer equipment for hydraulic test can be used to measure pressure of test zone directly, and it is frequently used to perform many kinds of hydraulic tests and take groundwater sample from borehole. The test method of this equipment mainly includes the test design, implementation, interpretation and synthetic analysis. By adopting the double packer equipment for hydraulic test, the parameter distribution of rock permeability along borehole can be acquired, as well as the connectivity, water conductivity and water bearing capacity of the disclosed structure and the chemical characteristics of the deep groundwater. It is a necessary method for the research and evaluation of the complex hypotonicity terrace site selection under geological conditions. This method is not only suitable for the geological disposal of high level radioactive waste, but also can be used in the site selection of underground facilities such as storage of petroleum and carbon dioxide. Meanwhile, it has a good application prospect in other hydrogeological investigation fields.

In-situ Characterization of Non-aqueous Nano-dispersion Systems by Freeze-etching TEM and Comparative Study with Laser Scattering Method

In-situ characterization of non-aqueous nano-dispersion systems（NANDS） by freeze-etching transmission electron microscope（FETEM） was reported.To improve just-for-once successive rate of specimen preparation and get good characterization results,an improving specimen preparation method of freezing etching was developed.Size,distribution and morphology of NANDS were directly visualized.Some information of particle dispersion feature and particle density can also be obtained.Reproductivity of the FETEM characterization is excellent.Comparing with laser scattering method,which is liable to give positive error especially for small size particle anchoring disperser,FETEM characterization can give more accurate measurement of particle size.Moreover,FETEM can give dispersion feature of nanoparticle in non-aqueous medium.

Participating in health care for total hip replacement patients:an integrative review

In recent years,with the continuous improvement of people's health requirements,the awareness of participating in disease diagnosis and treatment has also been constantly enhanced.Patient’s participation has become a hot issue in medical care policies and research practices.This article intends to review the research background of patient participation and necessity,status,form,significance and existing problems of total hip replacement patients'participation in health care in order to provide reference for the promotion participation in practice.

In-situ gas contents of a multi-section coal seam in Sydney basin for coal and gas outburst management

The gas content is crucial for evaluating coal and gas outburst potential in underground coal mining. This study focuses on investigating the in-situ coal seam gas content and gas sorption capacity in a representative coal seam with multiple sections (A1, A2, and A3) in the Sydney basin, where the CO_(2) composition exceeds 90%. The fast direct desorption method and associated devices were described in detail and employed to measure the in-situ gas components (Q_(1), Q_(2), and Q_(3)) of the coal seam. The results show that in-situ total gas content (Q_(T)) ranges from 9.48 m^(3)/t for the A2 section to 14.80 m^(3)/t for the A3 section, surpassing the Level 2 outburst threshold limit value, thereby necessitating gas drainage measures. Among the gas components, Q_(2) demonstrates the highest contribution to Q_(T), ranging between 55% and 70%. Furthermore, high-pressure isothermal gas sorption experiments were conducted on coal samples from each seam section to explore their gas sorption capacity. The Langmuir model accurately characterizes CO_(2) sorption behavior, with ft coefcients (R^(2)) greater than 0.99. Strong positive correlations are observed between in-situ gas content and Langmuir volume, as well as between residual gas content (Q_(3)) and sorption hysteresis. Notably, the A3 seam section is proved to have a higher outburst propensity due to its higher Q_(1) and Q_(2) gas contents, lower sorption hysteresis, and reduced coal toughness f value. The insights derived from the study can contribute to the development of efective gas management strategies and enhance the safety and efciency of coal mining operations.

In-situ stress of coal reservoirs in the Zhengzhuang area of the southern Qinshui Basin and its effects on coalbed methane development

In-situ stress is a critical factor influencing the permeability of coal reservoirs and the production capacity of coalbed methane(CBM)wells.Accurate prediction of in-situ stress and investigation of its influence on coal reservoir permeability and production capacity are significant for CBM development.This study investigated the CBM development zone in the Zhengzhuang area of the Qinshui Basin.According to the low mechanical strength of coal reservoirs,this study derived a calculation model of the in-situ stress of coal reservoirs based on the multi-loop hydraulic fracturing method and analyzed the impacts of initial fractures on the calculated results.Moreover,by combining the data such as the in-situ stress,permeability,and drainage and recovery data of CBM wells,this study revealed the spatial distribution patterns of the current in-situ stress of the coal reservoirs and discussed the impacts of the insitu stress on the permeability and production capacity.The results are as follows.(1)Under given fracturing pressure,longer initial fractures are associated with higher calculated maximum horizontal principal stress values.Therefore,ignoring the effects of the initial fractures will cause the calculated values of the in-situ stress to be less than the actual values.(2)As the burial depth increases,the fracturing pressure,closure pressure,and the maximum and minimum horizontal principal stress of the coal reservoirs in the Zhengzhuang area constantly increase.The average gradients of the maximum and minimum horizontal principal stress are 3.17 MPa/100 m and 2.05 MPa/100 m,respectively.(3)Coal reservoir permeability is significantly controlled by the magnitude and state of the current in-situ stress.The coal reservoir permeability decreases exponentially with an increase in the effective principal stress.Moreover,a low lateral pressure coefficient(less than 1)is associated with minor horizontal compressive effects and high coal reservoir permeability.(4)Under similar conditions,such as resource endowments,CBM well capacity is higher in primary structural coal regions with moderate paleotectonic stress modification,low current in-situ stress,and lateral pressure coefficient of less than 1.

二氧化碳置换法开采天然气水合物研究进展

应用CO_(2)置换法开采天然气水合物被认为是一种极具潜力的提高CH_(4)采收率和CO_(2)埋存率的技术。论述了CO_(2)及其混合气置换法开采天然气水合物的机理,梳理了CO_(2)混N_(2)/H_(2)及地热辅助CO_(2)提高水合物中CH_(4)采收率的技术进展。研究表明:①应用纯CO_(2)置换开采天然气水合物时,CH_(4)的采收率较低,而将CO_(2)与N_(2)、H_(2)以不同比例混合后注入天然气水合物藏中进行CH_(4)开采,能够有效提高CH_(4)的采收率。②CO_(2)与N_(2)或H_(2)混合注入水合物层时,多种气体分子在竞争吸附作用下降低了CH_(4)分子与水合物分子笼之间的范德华力,同时降低了混合气中CO_(2)的分压,导致水合物相平衡曲线上移,抑制了置换过程中CO_(2)水合物的生成速率,减轻了包裹作用的不利影响,从而提高CH_(4)采收率。③CO_(2)混合N_(2)注入开采水合物时,N_(2)的混入虽然能够减轻包裹作用的影响,但新形成的N_(2)水合物会堵塞CO_(2)进入水合物分子笼的通道,因此提高CH_(4)采收率效果有限。④在水合物层条件下H_(2)并不会形成新的水合物,而且混入少量的H_(2)又会与N_(2)发生吸附竞争,从而抑制N_(2)水合物的形成,故将低浓度的H_(2)气混入CO_(2)与N_(2)的混合气中能够进一步提高对水合物中CH_(4)的置换率,从而提高CH_(4)的采收率。因此,混入H_(2)被认为是提高CO_(2)置换开发水合物效果的重要途径。⑤混合气周期注气方式可明显提高水合物中CH_(4)的采收率和CO_(2)水合物藏封存率。⑥应用地热辅助CO_(2)开采水合物的方法也能够降低新形成水合物的包裹作用,同时实现CO_(2)在地热层和水合物层的两次埋存,在提高CH_(4)采收率的同时,大大提高CO_(2)在地层中的埋存率。

带式输送机不停机托辊更换车结构设计及特性分析

为提高煤矿带式输送机在更换损坏托辊时的维护效率,减小人工更换产生的安全风险,文中设计了一种可在带式输送机不停机状态下进行托辊更换的更换车。针对不停机更换托辊的工作要求,确定更换车的更换方案,并建立三维模型。采用D-H参数法建立更换车机械手的连杆坐标系,通过MATLAB软件机器人工具箱建立机械手模型,并用蒙特卡洛法确定机械手的工作空间,结果表明,其运动范围满足槽型托辊组3个托辊的更换。采用ADAMS软件对机械手拆卸和安装托辊过程进行仿真,得到损坏托辊和备用托辊的位移曲线,结合夹取结构的运动曲线和运行轨迹,结果表明,机械手的工作过程平稳流畅。采用ANSYS软件对更换车工作中关键受力部件支撑臂和支撑托辊架进行有限元分析,结果表明:两部件强度满足工作要求,保证更换车工作的可靠性。

浅谈湿法冶炼锌中上清液净化沉钴方法与应用

本文主要介绍了湿法炼锌硫酸锌溶液中钴的沉淀方法、工艺及生产现状,对传统的沉钴方法及工艺存在的优势、缺陷进行了分析,综述了近几年来沉钴技术上的研究进展及取得的进步,有助于提高企业技术水平及经济效益。

盾尾刷更换时液氮冻结温度场及冻结参数影响的数值模拟分析

为合理确定高水压下液氮冻结止水更换盾尾刷的冻结设计参数及掌握温度场变化规律,结合某过江通道长距离盾构掘进过程中盾尾刷更换时的液氮冻结止水工程,利用ADINA大型有限元分析软件建立液氮冻结止水及盾尾刷更换数值模型,模拟温度-时间变化曲线与现场实测数据对比,验证模型的合理性,并对土层、去路液氮温度、冻结管长度、冻结管间距、冻结方式进行敏感性因素分析。结果表明:1)冻结效果随土层的不同而发生改变,在卵石层、砾砂层、粉细砂层3种土层中,粉细砂层的冻结效果最差,卵石层最好;2)在有限的冻结时间内,去路液氮温度的不同,只影响土体从开始冻结至越过0℃完成相变这期间的降温速度,不影响完成冻结以后的土体降温速率;3)冻结管长度对土层冻结的影响较小,可以采用较短的冻结管,以降低施工成本和液氮消耗量,但不能过短,应保证其纵向有足够的支撑范围,经计算分析,当冻结管长度为1.52 m时,能在轴面处满足2.0 m的冻结壁厚度要求;4)冻结管间距对冻结效果影响大,冻结管越密,冻结速度越快,效果越好;5)在相同条件下,双环预埋冻结管液氮冻结效果优于管片上直接打孔液氮冻结。

生态系统休闲游憩价值评估--以北京密云区为例

作为生态产品总值核算的重要内容,生态系统文化服务主要包括休闲游憩、旅游康养与景观增值三个核算内容,但受公共产品性质的影响,休闲游憩服务缺乏市场价值,因此目前的研究很少涉及对生态系统休闲游憩价值的评估。而随着公园绿地等区域被广泛利用,其能为人们带来的休闲游憩服务也逐渐成为生态系统文化服务中不可忽视的重要组成部分。因此以北京密云区的公园绿地、滨水带与山地健身区为研究对象,运用替代成本法与支付意愿法对生态系统的休闲游憩价值进行评估与比较。结果表明,替代成本法评估的结果相对更合理;公园绿地、滨水带与山地健身区的休闲游憩价值分别为2.93亿元、4.54亿元、2.78亿元;密云区生态系统的休闲游憩价值为10.25亿元,其中费用成本6.69亿元,时间成本3.56亿元。

连续性肾脏替代治疗护理敏感质量指标体系的构建

目的构建连续性肾脏替代治疗护理敏感质量指标,为连续性肾脏替代治疗护理质量评价及管理提供参考依据。方法以“结构—过程—结果”模型为理论框架,通过研究小组讨论筛选指标,初步拟订连续性肾脏替代治疗护理敏感质量指标,采用德尔菲法进行2轮专家函询确定连续性肾脏替代治疗护理敏感质量指标,采用层次分析法计算指标权重。结果2轮函询专家积极系数分别为94%、100%,权威系数分别为0.856、0.870,协调系数分别为0.247、0.269。最终构建的连续性肾脏替代治疗护理敏感质量指标体系包括3项一级指标、7项二级指标、19项三级指标。结论本研究构建的连续性肾脏替代治疗护理敏感质量指标体系具有科学性和实用性,权重分配合理,可以为客观评价连续性肾脏替代治疗的护理质量提供参考依据。

早期心脏手术相关急性肾损伤患者连续性肾脏替代治疗系统化护理方案的构建

目的构建早期心脏手术相关急性肾损伤(CSA⁃AKI)患者连续性肾脏替代治疗(CRRT)系统化护理方案。方法采用文献分析、小组讨论等方法初步构建早期CSA⁃AKI患者CRRT系统化护理方案。基于德尔菲法,通过专家函询确定方案的条目,采用层次分析法确定条目的权重。结果两轮专家函询的问卷回收有效率均为100%;第一轮、第二轮专家函询的权威系数分别为0.888及0.909,各三级条目的重要性评分均值范围分别为3.84~4.84、4.10~5.00,标准差范围分别为0.43~1.20、0~0.61,肯德尔协调系数分别为0.124和0.158(P<0.05)。最终确定的系统化护理方案包含4个一级条目、15个二级条目、41个三级条目,各层次条目的一致性比率均<0.1。结论所构建的早期CSA⁃AKI患者CRRT系统化护理方案可为临床操作提供参考依据。

“Shamrock method”超声引导连续腰丛神经阻滞用于老年患者全膝关节置换术后镇痛的临床观察

目的：评价“Shamrock method”超声引导联合刺激仪定位下连续腰丛神经阻滞与连续股神经阻滞对全膝关节置换术后镇痛的临床效果。方法采用开放、随机对照的研究方法，选择解放军总医院2014年6月至2014年12月择期行单侧全膝关节置换术的老年患者80例，年龄65～87岁，美国麻醉医师协会（ASA）分级Ⅱ～Ⅲ级，随机均分为连续腰丛神经阻滞组（L组）和连续股神经阻滞组（F组）。L组患者采用“Shamrock method”超声引导联合刺激仪定位下行腰丛神经阻滞，F组则采用超声引导联合刺激仪定位下行股神经阻滞，两组穿刺成功后均注入0.2%罗哌卡因30ml并留置导管,术后镇痛泵背景剂量为0.2%罗哌卡因5ml/h。记录术后6，12，24，48h时静息状态视觉模拟评分法（VAS）评分，术后24，48h膝关节功能锻炼时VAS评分和肌力评分；记录术后局麻药中毒、恶心呕吐和神经损伤等不良反应的发生情况。结果与L组相比较，F组术后各时点静息状态和功能锻炼VAS评分均明显增高（P＜0.05），肌力评分两组间差异无统计学意义（P＞0.05）。两组均未见局麻药中毒、神经损伤发生，且恶心呕吐等不良反应发生率两组间差异无统计学意义。结论“Shamrock method”超声引导联合刺激仪定位下连续腰丛神经阻滞对于老年患者全膝关节置换术后镇痛的临床效果优于连续股神经阻滞。