地方院校材料合成与加工实验教学研究

为培养地方发展需要的人才,对材料合成与加工实验进行了改革,并对相关教学模式进行了探讨。     

Microstructure Evolution of Ni-Co Alloys During Crystallization and Amorphization Process

Journal of Superconductivity and Novel Magnetism - A molecular dynamics simulation has been conducted in Ni73Co27 and Ni74Co26 alloys during rapid solidification at the cooling rate of...     

Activation cross sections for reactions induced by 14 MeV neutrons on natural copper

The cross sections for the~(63)Cu(n,a)~(60(m+g))Co,~(65)Cu(n,2 n)~(64)Cu, and ~(65)Cu(n,p)~(65)Ni reactions have been studied in the neutron energy range of 13.5–14.8 MeV using the activation technique. The neutron beams were produced via the~3 H(d,n)~4 He reaction. The neutron energies of different directions in the measurements were determined beforehand by the method of cross section ratios for the~(90)Zr(n,2 n)~(89 m+g)Zr and ~(93)Nb(n,2 n)~(92 m)Nb reactions. The results in the present work were discussed and compared with measurement results found in the literatures.     

A density functional theory study on the interaction between UO_2~(2+) and the carbamoylphosphoramidic acid ligand for uranium extraction from seawater

Phosphorylurea molecules, which contain both phosphoryl and carbonyl groups, are considered efficient extractants for UO_2~(2+). This study aims to explain the complexation of UO_2~(2+)with carbamoylphosphoramidic acid(CPO), a simple model for phosphorylurea, for ligand design for uranium recovery from seawater using density functional theory calculations, natural bond order analysis,and the quantum theory of atoms in molecules. The results showed that, when CPO acts as a monodentate ligand, the affinity of phosphoryl for UO_2~(2+)is stronger than that of carbonyl, and CPO coordinates with UO_2~(2+)through the phosphoryl oxygen atom. When CPO serves as a bidentate ligand, both the phosphoryl and carbonyl oxygen atoms connect to UO_2~(2+), and the U–O(carbonyl) bond plays a more important role than the U–O(phosphoryl) bond in the interaction between UO_2~(2+)and CPO. This paradox may be caused by the significant charge transfer from the U–O(carbonyl) p bond orbital to the C–N σ antibond orbital of the bidentate CPO. The NH spacer between the phosphoryl and carbonyl groups could ensure the delocalization of the electron system of the molecule. The bidentate binding motif is favored by entropy and opposed by enthalpy, while the monodentate binding motif is favored by enthalpy and opposed by entropy. Ultimately, the bidentate binding motif is more favorable than the monodentate one. As expected, the interaction between UO_2~(2+)and the deprotonated CPO is stronger than that between UO_2~(2+)and the neutral CPO. Comparing the interaction between UO_2~(2+)and CPO with that between UO_2~(2+)and Nphenylcarbamoylphosphoramidic acid(Ph CPO), formed by replacing one hydrogen atom from the terminal nitrogen atom of CPO with a phenyl group, the phenyl substituent at the terminal nitrogen atom of Ph CPO shows a slightly negative effect on the interaction between UO_2~(2+)and Ph CPO.     

一种基于信任/不信任的信誉攻击防御策略及稳定性分析

虽然各电子商务企业采用多种信誉评价机制解决消费者对卖方或平台的信任问题,但是信誉评价系统仍然频繁地遭受各种攻击.这些攻击致使卖方的信誉排名和推荐排名被操控,大量诚实消费者被误导而购买了质量较差的商品.有研究者提出综合考虑消费者之间的信任和不信任信息可以使消费者更好地抵御信誉攻击.然而,现有工作存在“信任或不信任信息融合不足”以及“使用一组顾问评价所有卖方”等局限性,因此导致卖方信誉评价的针对性和准确性较差.提出了一种新的防御策略——T&D,它综合考虑了消费者的可信和不可信2个方面.此外,该策略为消费者设置了白名单(存储若干个最信任的评价者)和黑名单(存储若干个最不信任的评价者).利用黑名单净化白名单,诚实消费者可以找到更可信的评价者并依据这些评价者的评分和诚实消费者自身的经历准确评估每个卖方的信誉值.模拟实验结果显示：该策略在评估准确性和稳定性方面明显优于现有防御策略.     

面向网络功能虚拟化的高性能负载均衡机制

网络负载均衡器是实现网络功能虚拟化(network function virtualization, NFV)的重要功能组件,通过其准确的业务负载分担,运营商可以灵活、高效地实现业务能力增强和容量扩展.基于DPDK技术框架设计实现了面向NFV的高性能4层网络负载均衡机制及系统HVLB,能够灵活部署运行于主流虚拟化平台.HVLB整体采用软件定义网络(software defined networking, SDN)思想设计,实现调度策略制订和数据转发的有效分离.在转发端基于用户空间实现多核多队列高效数据处理架构,同时保证各处理队列间的数据访问隔离和任务处理均衡;在控制端基于网络链路和计算相结合的综合能力作为NF选择和转发策略的制订依据,在实施业务数据准确分发的基础上保障了网络性能.基于KVM的原型系统实验结果表明：与现有LVS系统相比,HVLB极大地提升了数据包处理与转发性能,并实现了64字节UDP数据包的线速转发.     

基于区块链的分布式物联网信任管理方法研究

随着物联网(Internet of things, IoT)技术的发展,在不同的物联网之间逐渐形成了大规模、异构化、动态化的分布式物联网环境.分布式物联网内的设备间与物联网管理机构间存在着广泛的合作需求,为此需要在其中建立信任机制以促进合作.然而,现有的信任机制研究大部分脱离于物联网环境,没有考虑物联网设备计算与存储能力有限且差异较大这一特点,造成抽象信任机制研究无法直接应用于物联网中;另一方面,现有的物联网信任问题研究都依赖于额外的可信第三方或域间信任假设,这在实际中是难以实现的.为了解决上述问题,借助区块链与风险理论,提出一种适用于分布式物联网的信任管理方法.具体地,将信任量化为对期望信用与风险的考察,并借助区块链实现信任数据的有效共享与安全性.实验与分析表明:该方案能够有效量化信任,保护数据不被篡改,且能够以较低的存储开销维护系统的正常运行.     

塔里木盆地巴什托超高压裂缝性油藏改善开发效果对策研究

针对巴什托超高压裂缝性油藏在开发过程中出现的含水上升快、产量下降快、底水能量弱等特点,在精细地质研究的基础上,对储层特征和油井见水规律进行了研究,建立了5种油井见水模式,对油藏实施的转抽、堵水、提液等措施进行了总结分析,为下一步提高开发效果提出了切实可行的技术方案。     

一种分布式异构带宽环境下的高效数据分区方法

在分布式大数据处理框架的作业运行过程中,会有大量的数据通过网络传输,数据在各节点之间传输所需的时间已成为作业运行的主要开销之一.在节点异构带宽的情况下,因为带宽瓶颈节点的存在,传统的数据分区方法效率低下.针对这个问题,建立了节点间的数据传输模型,该模型以降低数据传输时间为目标,根据各节点的上下行带宽和初始数据量大小,计算出各节点的最优数据分发比例.以该模型为基础,设计了基于带宽的数据分区方法,该数据分区方法使得各节点按最优数据分发比例来分配数据.最后在Apache Flink框架中将基于带宽的数据分区方法进行了实现,并通过实验进行了验证.实验结果表明:异构带宽条件下,基于带宽的数据分区方法可以有效减少数据分区所需的时间.     

A universal programmable driving circuit for spatial light modulators

ea of only 65 × 65μm2.