检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

矿井灾害危险与防治措施效果评估模型

煤炭科技 2003年第4期24卷 43-45页

作者： jozef kabiesz 窦林名波兰煤科总院中国矿业大学能源科学与工程学院江苏徐州221008

矿井自然灾害之间的相互影响及防治措施的应用效果评估对矿井安全生产具有很重要的意义。准确预测矿井灾害状态和防治措施的效果取决于对它们的详细描述,而提高其描写的准确性可采用模糊数学的方式。介绍了自然灾害和防治措施实施效果... 详细信息

矿井自然灾害之间的相互影响及防治措施的应用效果评估对矿井安全生产具有很重要的意义。准确预测矿井灾害状态和防治措施的效果取决于对它们的详细描述,而提高其描写的准确性可采用模糊数学的方式。介绍了自然灾害和防治措施实施效果评估的模糊数学模型。

关键词：矿井灾害影响模型模糊数学危险性防治措施评估模型

在线全文

学校读者我要写书评

暂无评论

神经网络预测矿震危险性

煤炭科技 2007年第4期28卷 71-74页

作者： jozef kabiesz 窦林名波兰矿山研究总院

开采冲击危险煤层时,需要对能量大于等于104 J矿震发生的时间和地点进行预测。但目前所预测的结果不能满足现场要求。依据波兰一个长壁工作面的矿震事件,研究了神经网络系统中输入数据类型和形式对矿震预测效果的影响,确定了提高预测效... 详细信息

开采冲击危险煤层时,需要对能量大于等于104 J矿震发生的时间和地点进行预测。但目前所预测的结果不能满足现场要求。依据波兰一个长壁工作面的矿震事件,研究了神经网络系统中输入数据类型和形式对矿震预测效果的影响,确定了提高预测效果的方法。实践证明,采用神经网络技术可以对矿震危险性进行预测。

关键词：震动神经网络危险性预测

在线全文

学校读者我要写书评

暂无评论

顶板岩层动力事件发生机理与防治方法

煤炭科技 2008年第1期29卷 55-58页

作者： Jan DRZEWIECKI jozef kabiesz 窦林名波兰矿山研究总院

在长壁开采过程中不可避免地会对顶板岩层产生强烈扰动,这种扰动可能扩展到开采区域以外的地方,并且岩石变形破坏的形式也不相同。当岩层坚硬时,储存的能量可能频繁地以高能量微震形式释放出来。当岩层本身所储存的能量无法缓慢释放时,... 详细信息

在长壁开采过程中不可避免地会对顶板岩层产生强烈扰动,这种扰动可能扩展到开采区域以外的地方,并且岩石变形破坏的形式也不相同。当岩层坚硬时,储存的能量可能频繁地以高能量微震形式释放出来。当岩层本身所储存的能量无法缓慢释放时,矿震现象常常会发生。研究表明,岩层本身所储存的能量与岩层本身的尺寸有密切的关系。因此,可以采用一些方法或措施来减少采矿诱发的矿震。该措施基于人为的方法破坏储存弹性能的岩层结构,其中最有效的方法之一就是采用定向水压致裂技术。

关键词：顶板岩层动力事件矿震定向水压致裂

Governance of decentralized autonomous organizations that produce open source software

在线全文

学校读者我要写书评

暂无评论

Blockchain(Research and Applications) 2024年第1期5卷 10-30页

作者： Paul van Vulpen jozef Siu Slinger Jansen Department of Information and Computer Science Utrecht University3584 CS Utrechtthe Netherlands Public Sector Solutions Centric2803 PB Goudathe Netherlands

Decentralized autonomous organizations(DAOs)have found use in the governance of open source software(OSS)***,the governance of an OSS producing DAO should match the particularities of OSS production while also overcoming the existing challenges of decentralized *** existing decentralized governance frameworks do not include all the governance activities of OSS ***,this study presents a governance framework for DAOs that produce *** framework is built upon a total of 34 articles on DAO and OSS *** framework was evaluated in three leading DAOs that produce *** evaluation underscores the significance of the framework and proves the potential of the systematic categorization of governance ***,we list emerging governance practices in various governance domains in this developing field.

关键词： Decentralized autonomous organizations Open source software Governance framework Blockchain Decentralized governance Case study research

Energy and blast performance of beryllium in a model thermobaric composition in comparison with aluminum and magnesium

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

Defence Technology（防务技术） 2024年第6期36卷 13-19页

作者： Thomas M.Klapotke Stanisław Cudziło Waldemar A.Trzcinski jozef Paszula Energetic Materials Research Department of ChemistryUniversity of Munich(LMU)Butenandtstrasse 5-13(D)81377MunichGermany Military University of Technology Faculty of Advanced Technologies and ChemistrySylwester Kaliski Str.200-908WarsawPoland

A direct comparison is made between the effectiveness of Al,Mg,and Be powders as additional fuels in model thermobaric compositions containing 20%fuel,20%ammonium perchlorate,and 60%RDX(1,3,5-Trinitro-1,3,5-triazacyclohexane)passivated with *** determined calorimetric measurements of the heat of detonation,along with the overpressure histories in an explosion chamber filled with nitrogen,were used to determine the quasi-static pressure(QSP)under anaerobic *** measurements were also performed in a semi-closed bunker,and all blast wave parameters generated after the detonation of 500 g charges of the tested explosives were *** calorimetry results,QSP values,and blast wave parameters(pressure amplitude,specific and total impulses)clearly indicate that Be is much more effective as an additional fuel than either Al or Mg in both anaerobic post-detonation reactions as well as the subsequent aerobic *** heat of detonation of the RDXwax/AP/Be explosive mixture is over 40%and 50%higher than that of the mixture containing aluminum and magnesium instead of beryllium,***,the TNT equivalent of the Be-containing composition due to the overpressure in the nitrogen-filled explosion chamber is 1.66,while the equivalent calculated using an air shock wave-specific impulse at a distance of 2.5 m is equal to *** high values of these parameters confirm the high reactivity of beryllium in both the anaerobic and aerobic stages of the thermobaric explosion.

关键词： Thermobaric explosives Beryllium Heat of detonation Quasi-static overpressure Blast wave parameters

In-situ study of the microstructure evolution during tension of a Mg-Y-Zn-Al alloy processed by rapidly solidified ribbon consolidation technique

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第5期12卷 2024-2040页

作者： Jeno Gubicza Kristián Máthis Péter Nagy Péter Jenei Zoltán Hegedus Andrea Farkas jozef Vesely Shin-ichi Inoue Daria Drozdenko Yoshihito Kawamura Department of Materials Physics Faculty of ScienceEotvos Loránd UniversityPázmány P.sétány 1/ABudapest H-1117Hungary Department of Physics of Materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116 Praha 2Czech Republic Deutsches Elektronen-Synchrotron DESY Notkestr.85Hamburg 22603Germany Magnesium Research Center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

Mg-Y-Zn-Al alloys processed by rapidly solidified ribbon consolidation(RSRC)technique exhibit an exceptional mechanical performance indicating promising application *** material has a bimodal microstructure consisting of fine recrystallized and coarse non-recrystallized grains with solute-rich stacking faults forming cluster arranged layers(CALs)and nanoplates(CANaPs),or complete long period stacking ordered(LPSO)*** order to reveal the deformation mechanisms,in-situ synchrotron X-ray diffraction line profile analysis was employed for a detailed study of the dislocation arrangement created during tension in Mg-0.9%Zn-2.05%Y-0.15%Al(at%)*** uncovering the effect of the initial microstructure on the mechanical performance,additional samples were obtained by annealing of the as-consolidated specimen at 300 and 400℃ for 2 *** heat treatment at 300℃ had no significant effect on the initial microstructure,its evolution during tension and,thus,the overall deformation behavior under tensile *** the other hand,annealing at 400℃ resulted in a significant increase of the recrystallized grains fraction and a decrease of the dislocation density,leading to only minor degradation of the mechanical *** maximum dislocation density at the failure of the samples corresponding to the plastic strain of 10-25% was estimated to be about 16-20×10^(14)m^(-2).The diffraction profile analysis indicated that most dislocations formed during tension were of non-basal and pyramidal types,what was also in agreement with the Schmid factor values revealed independently from orientation *** was also shown that the dislocation-induced Taylor hardening was much lower below the plastic strain of 3% than above this value,which was explained by a model of the interaction between prismatic dislocations and CANaPs/LPSO plates.

关键词： Mg-Zn-Y-Al alloy Long period stacking ordered(LPSO)phase Cluster arranged nanoplates(CANaPs) Annealing Tension Dislocation density Hardening

Synthesis and crystal structure study of 2′-Se-adenosine-derivatized DNA

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2010年第1期53卷 78-85页

作者： SALON jozef Department of Chemistry Georgia State University

The selenium derivatization of nucleic acids is a novel and promising strategy for 3D structure determination of nucleic *** can serve as an excellent anomalous scattering center to solve the phase problem,which is one of the two major bottlenecks in macromolecule X-ray *** other major bottleneck is *** has been demonstrated that the incorporated selenium functionality at the 2′-positions of the nucleosides and nucleotides is stable and does not cause significant structure ***,it was observed that the 2′-Se-derivatization could facilitate crystallization of oligonucleotides with fast crystal growth and high diffraction ***,we describe a convenient synthesis of the 2′-Se-adenosine phosphoramidite,and report the first synthesis and X-ray crystal structure determination of the DNA containing the 2′-Se-A *** 3D structure of 2′-Se-A-DNA decamer 5′-GTACGCGT(2′-Se-A)C-3′2 was determined at 1.75 ? resolution,the 2′-Se-functionality points to the minor groove,and the Se-modified and native structures are virtually ***,we have observed that the 2′-Se-A modification can greatly facilitate the crystal growth with high diffraction *** conjunction with the crystallization facilitation by the 2′-Se-U and 2′-Se-T,this novel observation on the 2′-Se-A functionality suggests that the 2′-Se moiety is sole responsible for the crystallization facilitation and the identity of nucleobases does not influence the crystal growth significantly.

关键词： selenium derivatization nucleic acid adenosine X-ray crystallography structure determination

Basic theorem as representation of heterogeneous concept lattices

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2015年第4期9卷 636-642页

作者： jozef POCS Jana POCSOVA Palacky University Olomouc Department of Algebra and Geometry Olomouc 779 00 Czech Republic Mathematical Institute Slovak Academy of Sciences Kosice 040 01 Slovakia Technical University of Kosice BERG Faculty Institute of Control and Informatization of Production Processes Ko~ice 043 84 Slovakia

We propose a method for representing heteroge- neous concept lattices as classical concept lattices. Particu- larly, we describe a transformation of heterogeneous formal context into a binary one, such that corresponding concept lattices will be isomorphic. We prove the correctness of this transformation by the basic theorem for heterogeneous as well as classical concept lattices.

关键词： basic theorem heterogeneous concept lattice,representation

Corrosion Resistance of AZ91 Magnesium Alloy after Laser Remelting Treatment

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2016年第5期31卷 1075-1080页

作者： STRZELECKA Monika IWASZKO jozef MALIK Marcin A Czestochowa University of Technology 42-200 Czestochowa Poland

The main objective of the study was the modification of the surface layer of magnesium alloy by the COlaser. The studied material was the commercial AZ91 magnesium alloy. The effectiveness of the alternations caused by the remelting process was verified on the basis of microscopic observation and corrosion investigations, i e, recording of potentiodynamic polarization curves, electrochemical noise measurements and hydrogen evolution rate measurements. For the adopted range of the treatment parameters, favourable changes were observed in the surface layer such as the refinement of structure and more uniform arrangement of individual phases. As a consequence of those favourable structural changes the improvement of the corrosion resistance of the alloy was achieved in comparison to its non-remelted equivalent. For the treated material corrosion rates expressed as corrosion current densities were at least three times lower than the appropriate values for the untreated alloy comparing them for the same period of samples immersion in the test solution. The obtained results have confirmed the effectiveness of the applied surface treatment resulting in favourable changes in the structure and corrosion properties of the AZ91 magnesium alloy.

关键词： magnesium alloy CO_2 laser surface layer modification corrosion