氯化N-[3-长链烷氧(双)乙烯氧-2-羟]丙基-N,N,N-三甲基铵的合成及性质

以溴代烷和乙二醇或一缩二乙二醇为原料合成长链烷基（双）氧乙烯醇（收率为７５％ ）,然后在相转移催化条件下和环氧氯丙烷反应得到长链烷基（双）氧乙烯缩水甘油醚（收率为９０％ ）,后者和三甲胺盐酸盐反应得到氯化Ｎ［３长链烷氧（双）乙烯氧２羟］丙基Ｎ,Ｎ,Ｎ三甲基铵（收率为９１％ ）,其结构通过红外光谱、核磁共振氢谱和元素分析结果得以证实,测定了产物的γｃｍ 及ｃｍ ｃ     

Two-phase node deployment for target coverage in rechargeable WSNs using genetic algorithm and integer linear programming

The Journal of Supercomputing - Node deployment is a matter of considerable concern in designing wireless sensor networks (WSNs). This paper studies this issue in the context of rechargeable WSNs...     

Multi-level trust-based intelligence schema for securing of internet of things (IoT) against security threats using cryptographic authentication

The Journal of Supercomputing - The internet of things (IoT) is able to provide a prediction of linked, universal, and smart nodes that have autonomous interaction when they present services....     

A novel approach for multicast call acceptance in multi-channel multi-radio wireless mesh networks

Multicasting is an efficient data transmission approach for group communication applications in multi-channel multi-radio wireless mesh networks. In this paper we have studied the problem of accepting on-line multicast requests, which is quite important for supporting multimedia applications. Our proposed algorithm investigates the acceptance of an arrived call in two phases. In the first phase, a loop-free mesh backbone is constructed. In this mesh, the set of possible parents of each node is limited to the neighbors that are one hop closer to the source node. The neighbors with the same distance from the source node are also acceptable under the circumstance that two neighboring nodes cannot be the possible parents of each other. Next, a sub-optimal mathematical model has been proposed for tree construction over the obtained mesh. The derived multicast trees utilize the minimum amount of bandwidth; are load-balanced; and exploit wireless broadcast advantage. The results show that the proposed algorithm improves the rate of multicast call acceptance by 40% on average compared to previous algorithms in a short running time.     

Novel dynamic load balancing algorithm for cloud-based big data analytics

Big data analytics in cloud environments introduces challenges such as real-time load balancing besides security, privacy, and energy efficiency. This paper proposes a novel load balancing algorithm in cloud environments that performs resource allocation and task scheduling efficiently. The proposed load balancer reduces the execution response time in big data applications performed on clouds. Scheduling, in general, is an NP-hard problem. Our proposed algorithm provides solutions to reduce the search area that leads to reduced complexity of the load balancing. We recommend two mathematical optimization models to perform dynamic resource allocation to virtual machines and task scheduling. The provided solution is based on the hill-climbing algorithm to minimize response time. We evaluate the performance of proposed algorithms in terms of response time, turnaround time, throughput metrics, and request distribution with some of the existing algorithms that show significant improvements.

     

A dynamic data dissemination mechanism for Cassandra NoSQL data store

The Journal of Supercomputing - Cassandra as a type of NoSQL databases has been put forward so as to surmount the hurdles of traditional relational databases in the scope of big data as well as...     

纳米镍粉制备的研究进展

根据制备过程中物质所在的体系不同,较详细地综述了纳米镍粉的制备方法,包括气相法、液相法和固相法.并简单地介绍了纳米镍粉在各个领域的应用情况,展望了其作为石油和化工催化材料、磁性材料、导电浆料、纳米涂层材料、硬质合金粘接剂及军事含能材料等的应用前景.     

光线对四溴乙烷合成反应的影响

主要研究了光线照射对四溴乙烷合成过程的影响.研究表明,光线条件对溴素与乙炔加成反应过程有非常明显的影响.增加光照,可以加快溴素与乙炔的加成反应速率,缩短合成反应时间,并使合成反应在夜晚正常进行.同时,增加光照可使溴素与乙炔的加成反应进行得更加完全,从而降低副产物生成量,提高溴素的转化率和四溴乙烷收率.初步分析了光线照射影响四溴乙烷合成反应的作用机理.     

Nonintrusive Monitoring and Control of Metallurgical Processes by Acoustic Measurements

The feasibility of developing a new online monitoring technique based on the characteristic acoustic response of gas bubbles in a liquid has been investigated. The method is intended to monitor the chemistry of the liquid through its relation to the bubble sound frequency. A low-temperature model consisting of water and alcohol mixtures was established, and the frequency of bubbles rising under varying concentrations of methanol was measured. It was shown that the frequency of the sound created by bubble pulsation varies with the percentage of alcohol in water. The frequency drops sharply with the increase in methanol content up to 20 wt pct, after which the decreases is gradual. Surface tension seems to be a critical liquid property affecting the sound frequency through its two-fold effects on the bubble size and the pulsation domain. The dependence between the frequency and the liquid composition suggests the feasibility of developing an acoustic-based technique for process control purposes.     

A platform independent distributed IPC mechanism in support of programming heterogeneous distributed systems

Interprocess communication (IPC) is a well-known technique commonly used by programs running on homogeneous distributed systems. However, it cannot be used readily and efficiently by programs running on heterogeneous distributed systems. This is because it must be given a uniform interface either by a set of middleware or more efficiently properly ported to the kernel of all varieties of open source and closed source proprietary operating systems running on heterogeneous nodes of distributed systems. This is particularly problematic to achieve when the kernel code of closed source operating systems are inaccessible to third parties. We propose an alternative nonproprietary approach to enable the use of IPC in heterogeneous distributed systems by wrapping IPC calls from the kernel of closed source operating systems, and converting them into equivalent IPC calls that are efficiently implemented inside the kernel code of open source operating systems. To show the superiority of our approach, we developed a wrapper for converting MS-Windows IPC calls into equivalent Linux IPC calls and benched our approach on a hybrid computer cluster running both types of operating systems.