排序方式: 共有27条查询结果,搜索用时 15 毫秒
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采用几种消解方法对样品进行前处理,建立了电感耦合等离子体-原子发射光谱法(ICP-AES)同时测定导热硅脂中铅、镉等有害金属元素的方法.结果表明:高温灰化法Pb、Cd有损失;(1 1)王水湿法消解法Pb有损失;硝酸-高氯酸湿法消解法Pb和Cd几乎无损失;该方法精密度范围为0.22%-2.40%,Pb和Cd检出限分别为0.030μg·mL-1和0.006μg·mL-1.与石墨炉原子吸收光谱法(GFAAS)相比,ICP-AES具有简单、快速、准确等特点. 相似文献
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半导体制冷电脑CPU恒温散热研究 总被引:1,自引:1,他引:0
用风冷的方法给CPU降温存在着降温效率低、反应速度慢、风扇的机械转动可靠性差、噪音大等弊病.因此,这里设计了一种用半导体制冷降温的装置来提高CPU的散热效率.它用温度传感器检测电脑CPU温度,当CPU温度超过设定温度的时侯,控制电路供电使半导体制冷块制冷,使CPU温度保持恒定.为防止冷凝结露,采用绝热材料密封导热铜板及... 相似文献
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Danxia Wang Yanan Li Hongen Jia 《Numerical Methods for Partial Differential Equations》2023,39(2):1251-1265
In this paper, we present a two-grid finite element method for the Allen-Cahn equation with the logarithmic potential. This method consists of two steps. In the first step, based on a fully implicit finite element method, the Allen-Cahn equation is solved on a coarse grid with mesh size H. In the second step, a linearized system whose nonlinear term is replaced by the value of the first step is solved on a fine grid with mesh size h. We give the energy stabilities of the traditional finite element method and the two-grid finite element method. The optimal convergence order of the two-grid finite element method in H1 norm is achieved when the mesh sizes satisfy h = O(H2). Numerical examples are given to demonstrate the validity of the proposed scheme. The results show that the two-grid method can save the CPU time while keeping the same convergence rate. 相似文献
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集成XGATE协处理器内核的S12XE系列双核单片机具有处理速度快、反应时间短、功耗低等优点,在嵌入式应用中具有独特优势和很好的应用前景。本文采用16位双核单片机MC9S12XEQ512作为主控制器,以集成信号和电源隔离功能的CAN收发器芯片ADM3053来实现CAN接口电路,设计并实现了一个可以连接3个CAN通信子网的CAN网关,有效实现了系统的小型化、低功耗、低成本。采用双核处理技术来优化CAN网关的处理流程,由协处理器XGATE来处理各种中断,S12X主CPU则专注于协议处理和消息转发。实际应用表明,系统运行稳定可靠,与传统的采用单处理器实现的CAN网关相比,系统的数据吞吐能力和实时性得到了明显改善。 相似文献
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A one-step 5-stage Hermite-Birkhoff-Taylor method, HBT(12)5, of order 12 is constructed for solving nonstiff systems of differential equations y′=f(t,y), y(t0)=y0, where y∈Rn. The method uses derivatives y′ to y(9) as in Taylor methods combined with a 5-stage Runge-Kutta method. Forcing an expansion of the numerical solution to agree with a Taylor expansion of the true solution to order 12 leads to Taylor- and Runge-Kutta-type order conditions which are reorganized into Vandermonde-type linear systems whose solutions are the coefficients of the method. HBT(12)5 has a larger interval of absolute stability than Dormand-Prince DP(8, 7)13M and Taylor method T12 of order 12. The new method has also a smaller norm of principal error term than T12. It is superior to DP(8, 7)13M and T12 on the basis the number of steps, CPU time and maximum global error on common test problems. The formulae of HBT(12)5 are listed in an appendix. 相似文献
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CPU散热片温度场模拟分析及其材料和尺寸选择的研究 总被引:8,自引:0,他引:8
对CPU的Cu—Al散热片进行了数值模拟热分析,研究了在室温、强迫对流的条件下的温度分布及散热片材料和几何尺寸对其传热性能的影响,并计算出模块较佳的材料和尺寸参数。有限元数值模拟分析值与实验测试值的比较结果表明,采用有限元热分析技术对CPU散热片进行数值模拟是可行的,为CPU散热片的设计提供了有效的方法。 相似文献
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《Journal of computational science》2014,5(2):90-98
The use of graphics hardware for non-graphics applications has become popular among many scientific programmers and researchers as we have observed a higher rate of theoretical performance increase than the CPUs in recent years. However, performance gains may be easily lost in the context of a specific parallel application due to various both hardware and software factors. JPEG 2000 is a complex standard for data compression and coding, that provides many advanced capabilities demanded by more specialized applications. There are several JPEG 2000 implementations that utilize emerging parallel architectures with the built-in support for parallelism at different levels. Unfortunately, many available implementations are only optimized for a certain parallel architecture or they do not take advantage of recent capabilities provided by modern hardware and low level APIs. Thus, the main aim of this paper is to present a comprehensive real performance analysis of JPEG 2000. It consists of a chain of data and compute intensive tasks that can be treated as good examples of software benchmarks for modern parallel hardware architectures. In this paper we compare achieved performance results of various JPEG 2000 implementations executed on selected architectures for different data sets to identify possible bottlenecks. We discuss also best practices and advices for parallel software development to help users to evaluate in advance and then select appropriate solutions to accelerate the execution of their applications. 相似文献