A Study of the Thermal Conductivity Property of the High-level Radioactive Waste Repository:The Case of Beishan Preselected Site,Gansu Province

The research and development of high-level radioactive waste(HLW)repository is a long-term systematic engineering project.Normally,it involves such stages as foundation study,site selection and assessment,underground research laboratory testing, and the design,construction,operation,and close of the repository.The key issue in repository design

Active source seismic imaging on near-surface granite body:case study of siting a geological disposal repository for high-level radioactive nuclear waste

In order to research whether it is suitable to set a geological disposal repository for high-level radioactive nuclear waste into one target granite body,two active source seismic profles were arranged near a small town named Tamusu,Western China.The study area is with complex surface conditions,thus the seismic exploration encountered a variettraveltimey of technical difculties such as crossing obstacles,de-noising harmful scattered waves,and building complex near-surface velocity models.In order to address those problems,techniques including cross-obstacle seismic geometry design,angle-domain harmful scattered noise removal,and an acoustic wave equation-based inversion method jointly utilizing both the and waveform of frst arrival waves were adopted.The fnal seismic images clearly exhibit the target rock’s unconformable contact boundary and its top interface beneath the sedimentary and weathered layers.On this basis,it could be confrmed that the target rock is not thin or has been transported by geological process from somewhere else,but a native and massive rock.There are a few small size fractures whose space distribution could be revealed by seismic images within the rock.The fractures should be kept away.Based on current research,it could be considered that active source seismic exploration is demanded during the sitting process of the geological disposal repository for nuclear waste.The seismic acquisition and processing techniques proposed in the present paper would ofer a good reference value for similar researches in the future.

Estimating shear strength of high-level pillars supported with cemented backfilling using the HoekeBrown strength criterion

Deep metal mines are often mined using the high-level pillars with subsequent cementation backfilling(HLSCB)mining method.At the design stage,it is therefore important to have a reasonable method for determining the shear strength of the high-level pillars(i.e.cohesion and internal friction angle)when they are supported by cemented backfilling.In this study,a formula was derived for the upper limit of the confining pressure σ3max on a high-level pillar supported by cemented backfilling in a deep metal mine.A new method of estimating the shear strength of such pillars was then proposed based on the Hoek eBrown failure criterion.Our analysis indicates that the horizontal stress σhh acting on the cemented backfill pillar can be simplified by expressing it as a constant value.A reasonable and effective value for σ3max can then be determined.The value of s3max predicted using the proposed method is generally less than 3 MPa.Within this range,the shear strength of the high-level pillar is accurately calculated using the equivalent MohreCoulomb theory.The proposed method can effectively avoid the calculation of inaccurate shear strength values for the high-level pillars when the original HoekeBrown criterion is used in the presence of large confining pressures,i.e.the situation in which the cohesion value is too large and the friction angle is too small can effectively be avoided.The proposed method is applied to a deep metal mine in China that is being excavated using the HLSCB method.The shear strength parameters of the high-level pillars obtained using the proposed method were input in the numerical simulations.The numerical results show that the recommended level heights and sizes of the high-level pillars and rooms in the mine are rational.

Research on the Path of Cultivating High-Level Technical and Skilled Talents in Vocational Undergraduate Colleges and Universities

This paper explores strategies to cultivate high-level technical talents in vocational undergraduate colleges by analyzing their development,the essence of such talents,and proposing several key measures.Strategies include optimizing professional settings and curricula,enhancing school-enterprise cooperation and the integration of industry-university-research,improving teaching staff quality and educational standards,and expanding international cooperation.The importance of policy support and funding and establishing robust quality assurance systems is emphasized for effectively cultivating skilled talents in vocational undergraduate colleges.

Drugs@FDA、FDA Online Label Repository和DailyMed 三大开放获取药品说明书数据库的比较研究

目的:为药学工作人员根据不同需求选择不同的药品说明书数据库提供参考。方法:搜集Drugs@FDA、FDA Online Label Repository和DailyMed三大开放获取药品说明书数据库的信息组织方式,从检索功能设置、检索结果显示内容、数据来源与服务目标三个方面进行比较分析。结果与结论:在检索功能上,以DailyMed最丰富;在检索结果显示内容上,DailyMed的数据格式化程度最高,FDA Online Label Repository次之,而Drugs@FDA只进行了部分格式化;3个数据库都提供页面复制和打印的功能,其中DailyMed的界面更为友好、内容更开放、提供了全部下载功能;在数据来源与服务目标上,Drugs@FDA和FDA Online Label Repository的系统开发者都为FDA,DailyMed为美国国立医学图书馆,Drugs@FDA采用的数据来源为经过FDA严格审批之后的药品说明书,对某一药品信息的描述最全面;FDA Online Label Repository则为厂商提交给FDA的原始说明书,其内容最新,甚至有未上市的药品;DailyMed采用的数据来源取自于已上市的药品包装盒上的信息,还包括很多上市但未经过严格审批的说明书信息,其覆盖药品最全。

Ontology and metadata for online learning resource repository management based on semantic web

An ontology and metadata for online learning resource repository management is constructed. First, based on the analysis of the use-case diagram, the upper ontology is illustrated which includes resource library ontology and user ontology, and evaluated from its function and implementation; then the corresponding class diagram, resource description framework （RDF） schema and extensible markup language （XML） schema are given. Secondly, the metadata for online learning resource repository management is proposed based on the Dublin Core Metadata Initiative and the IEEE Learning Technologies Standards Committee Learning Object Metadata Working Group. Finally, the inference instance is shown, which proves the validity of ontology and metadata in online learning resource repository management.

聚集学术机构知识的中心机构库(Institutional Repository)探析

本文首先介绍了机构库的定义及产生的原因,阐述了机构库的特点及国内外相关项目,然后从知识产权保护、经费管理、质量控制等方面论述了机构库存在的问题,最后分析了图书馆应如何面对机构库带来的机遇与挑战。

机构知识库(Institutional Repository)及其案例研究

阐述了机构知识库的基本理论,对典型的机构知识库系统DSpace进行了分析,阐述了DSpace的体系结构、数字资源的提交及查找等方面的情况,以期对国内机构知识库的建设有所裨益。

基于XML的开放式Browser／Repository的WEB架构

鉴于目前浏览器不能同时支持多种标注语言的缺陷，提出了一种基于XML的开放式Browser和Repository的四层Web体系，并做了较系统的论述。

浅析PowerSoft Repository系统表在软件开发中的应用

讨论了PowerSoft Repository系统表在软件开发中的一些应用，如动态报表、数据备份和数据恢复等。

面向XML Repository搜索引擎的研究与实现

由于XML开发者可以随意定义自己的元素,就可能导致相同的元素表示不同的信息或相同的信息由不同的元素表示,这种现象使得人们交换XML文档相当困难。为了解决这一问题,许多团体组织开发了XMLRepository。目前主流的搜索机制并不适合XMLRepository,因此针对XMLRepository开发搜索引擎成为一个新的课题。本文通过分析XMLRepository的特点和主流搜索引擎的局限性,根据引入的“本体论”和“带有不完整信息的XML树”概念,为XML文档模式提出一种新的搜索引擎的模型XRDS,并通过实验验证。

Magnetotelluric extremum boundary inversion based on different stabilizers and its application in a high radioactive waste repository site selection

Geophysical inversion under different stabilizers has different descriptions of the target body boundary,especially in complex geological structures.In this paper,we present an extremum boundary inversion algorithm based on different stabilizers for electrical interface recognition.Firstly,we use the smoothest and minimum-support stabilizing functional to study the applicability of adaptive regularization inversion algorithm.Then,an electrical interface recognition method based on different stabilizers is developed by introducing extremum boundary inversion algorithm.The testing shows that the adaptive regularization inversion method does work for different stabilizers and has a low dependence on the initial models.The ratio of the smooth and focusing upper and lower boundaries obtained using the extremum boundary inversion algorithm can clearly demarcate electrical interfaces.We apply the inversion algorithm to the magnetotelluric(MT)data collected from a preselected area of a high-level-waste clay-rock repository site in the Tamusu area.We recognized regional structures with smooth inversion and the local details with focusing inversion and determined the thickness of the target layer combined with the geological and drilling information,which meets the requirement for the site of the high-level waste clay-rock repository.

Experimental study on the physico-mechanical properties of Tamusu mudstone — A potential host rock for high-level radioactive waste in Inner Mongolia of China

Tamusu mudstone, located in Bayin Gobi Basin in Inner Mongolia of China, has been selected as a potential host rock for high-level radioactive waste(HLW) disposal in China. A series of tests has been carried out, including X-ray diffraction(XRD) tests, scanning electron microscopy(SEM) tests, disintegration tests, permeability tests and triaxial compression tests, to estimate the physico-mechanical properties of Tamusu mudstone in this work. The mineral composition of Tamusu mudstone was analyzed and it was considered as a stable rock due to its low disintegration rate, i.e. approximately 0.11%after several wet/dry cycles. Based on the results of permeability test, it was found that Tamusu mudstone has a low permeability, with the magnitude of about 10—20m^(2). The low permeability makes the mudstone well prevent nuclide migration and diffusion, and might be influenced by temperature.The triaxial tests show that Tamusu mudstone is a stiff mudstone with high compressive strength, which means that the excavation disturbed zone would be smaller compared to other types of mudstone due to construction and operation of HLW repositories. Finally, the properties of Tamusu mudstone were compared with those of Opalinus clay, Callovo-Oxfordian(COx) argillite, and Boom clay to further discuss the possibility of using Tamusu mudstone as a potential nuclear waste disposal medium.

Thermo-hydro-mechanical behavior of clay rock for deep geological disposal of high-level radioactive waste

In the context of deep geological disposal of radioactive waste in clay formations, the thermo-hydro- mechanical （THM） behavior of the indurated Callovo-Oxfordian and Opalinus clay rocks has been extensively investigated in our laboratory under repository relevant conditions： （1） rock stress covering the range from the lithostatic state to redistributed levels after excavation; （2） variation of the humidity in the openings due to ventilation as well as hydraulic drained and undrained boundary conditions; （3） gas generation from corrosion of metallic components within repositories; and （4） thermal loading from high-level radioactive waste up to the designed maximum temperature of 90 ~C and even beyond to 150 ~C, Various important aspects concerning the long-term barrier functions of the clay host rocks have been studied： （1） fundamental concept for effective stress in the porous clay-water system; （2） stress- driven deformation and damage as well as resulting permeability changes; （3） moisture influences on mechanical properties; （4） self-sealing of fractures under mechanical load and swelling]slaking of clay minerals upon water uptake; （5） gas migration in fractured and resealed claystones; and （6） thermal impact on the hydro-mechanical behavior and properties, Major findings from the investigations are summarized in this paper,

Establishing the knowledge repository of rapidly solidified aging Cu-Cr-Zr alloy on the artificial neural-network

The non-linear relationship between parameters of rapidly solidified agingprocesses and mechancal and electrical properties of Cu-Cr-Zr alloy is available by using asupervised artificial neural network (ANN). A knowledge repository of rapidly solidified agingprocesses is established via sufficient data learning by the network. The predicted values of theneural network are in accordance with the tested data. So an effective measure for foreseeing andcontrolling the properties of the processing is provided.

The Beishan underground research laboratory for geological disposal of high-level radioactive waste in China:Planning, site selection,site characterization and in situ tests

With the rapid development of nuclear power in China, the disposal of high-level radioactive waste（HLW） has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories（URLs） play an important and multi-faceted role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China＇s URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area,located in Gansu Province of northwestern China, has been selected as the final site for China＇s first URL built in granite. In the process of characterizing the Xinchang URL site, a series of investigations,including borehole drilling,geological mapping, geophysical surveying,hydraulic testing and in situ stress measurements, has been conducted. The investigation results indicate that the geological,hydrogeological, engineering geological and geochemical conditions of the Xinchang site are very suitable for URL construction. Meanwhile, to validate and develop construction technologies for the Beishan URL, the Beishan exploration tunnel（BET）, which is a 50-m-deep facility in the Jiujing sub-area, has been constructed and several in situ tests, such as drill-and-blast tests, characterization of the excavation damaged zone（EDZ）, and long-term deformation monitoring of surrounding rocks, have been performed in the BET. The methodologies and technologies established in the BET will serve for URL construction.According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed and necessary in situ tests in the URL are planned.

High-level radioactive waste disposal in China: update 2010

For geological disposal of high-level radioactive waste （HLW）, the Chinese policy is that the spent nuclear fuel （SNF） should be reprocessed first, followed by vitrification and final disposal. The preliminary repository concept is a shaft-tunnel model, located in saturated zones in granite, while the final waste form for disposal is vitrified high-level radioactive waste. In 2006, the government published a long-term research and development （R＆D） plan for geological disposal of high-level radioactive waste. The program consists of three steps： （1） laboratory studies and site selection for a HLW repository （2006-2020）; （2） underground in-situ tests （2021-2040）; and （3） repository construction （2041-2050） followed by operation. With the support of China Atomic Energy Authority, comprehensive studies are underway and some progresses are made. The site characterization, including deep borehole drilling, has been performed at the most potential Beishan site in Gansu Province, Northwestern China. The data from geological and hydrogeological investigations, in-situ stress and permeability measurements of rock mass are presented in this paper. Engineered barrier studies are concentrated on the Gaomiaozi bentonite. A mock-up facility, which is used to study the thermo-hydro-mechano-chemical （THMC） properties of the bentonite, is under construction. Several projects on mechanical properties of Beishan granite are also underway. The key scientific challenges faced with HLW disposal are also discussed.

sRNAanno-a database repository of uniformly annotated small RNAs in plants

Small RNAs(sRNAs)are essential regulatory molecules,and there are three major sRNA classes in plants:microRNAs(miRNAs),phased small interfering RNAs(phased siRNAs or phasiRNAs),and heterochromatic siRNAs(hc-siRNAs).Excluding miRNAs,the other two classes are not well annotated or available in public databases for most sequenced plant genomes.We performed a comprehensive sRNA annotation of 143 plant species that have fully sequenced genomes and next-generation sequencing sRNA data publicly available.The results are available via an online repository called sRNAanno(www.plantsRNAs.org).Compared with other public plant sRNA databases,we obtained was much more miRNA annotations,which are more complete and reliable because of the consistent and highly stringent criteria used in our miRNA annotations.sRNAanno also provides free access to genomic information for>22,721 PHAS loci and>22 million hc-siRNA loci annotated from these 143 plant species.Both miRNA and PHAS loci can be easily browsed to view their main features,and a collection of archetypal trans-acting siRNA 3(TAS3)genes were annotated separately for quick access.To facilitate the ease of sRNA annotation,sRNAanno provides free service for sRNA annotations to the community.In summary,the sRNAanno database is a great resource to facilitate genomic and genetic research on plant small RNAs.

Migration of Some Elements and Radionuclides across aGranite-Granite Contact Zone: A Natural Analoguefor Safe Disposal of High-Level Radwastes

Abstract Elements and natural radionuclides in the contact zone of two granites with different ages would migrate from one to the other because of the difference in their chemical contents and later water-rock interactions. This migration could serve as an analogue for the near-field process of radwastes in a high-level radwaste deep geological disposal repository.

Three-dimensional numerical simulation of methane drainage by high-level drill holes in a lower protective coal seam with a “U” type face

Different drill-hole positions may produce different drainage results in low protective coal seams.To investigate this possibility,a 3D stope model is established,which covers three kinds of drill holes.The FLUENT computational fluid mechanics software is used to solve the mass,momentum and species conservation equations of the model.The spatial distributions of oxygen and methane was obtained by calculations and the drainage results of different drill-hole positions were compared.The results show that,from top to bottom,methane dilution by oxygen weakens gradually from the intake to the return side,and methane tends to float;methane and oxygen distribute horizontally.The high-level crossing holes contribute to better methane drainage and a greater level of control.Around these holes,the methane density decreases dramatically and a "half circle"distribution is formed.The methane density decreases on the whole,but a proportion of the methane moves back to deep into the goaf.The research findings provide theoretical grounds for methane drainage.