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排序方式: 共有125条查询结果,搜索用时 15 毫秒
1.
从节能的观点出发,根据热力学原理和传递过程的理论,对冷却排管内湍流传热过程进行分析,研究损失随雷诺数的变化规律,探讨冷却排管的节能设计问题。  相似文献   
2.
The EGS4 code, developed at Stanford Linear Accelerator Center, simulates electron-photon cascading phenomena. The original code is inherently sequential: processing one particle at a time. This paper reports on a series of experiments in parallelizing different versions of EGS4. Our parallel experiments were run on a 30-processor Sequent Balance B21 and a 6-processor Symmetry S27. We have considered the following approaches for parallel execution of this application code:
1. (1) Original sequential version modified for parallel processing: 1 processor;
2. (2) Version 1 run multiprocessed: 1 to 29 processors;
3. (3) Sequential version modified for large-grain parallel processing: 1 procssor;
4. (4) Version 3 run using the Sequent Microtasking Library: 1 to 29 processors.

For each approach, we discuss the relative advantages and disadvantages in the areas of coding effort, understandability and portability, as well as performance, and outline a new parallelization approach we are currently pursuing based on Large-Grain Data Flow techniques.  相似文献   

3.
Recently, polyvinyl chloride (PVC) shower hoses have hardened throughout the eastern Shizuoka Prefecture, Japan. According to the elemental analysis results, the carbon and oxygen concentrations were much lower in the damaged hoses. These findings reveal that oxygen-containing, carbon-based plasticisers may leach from the damaged hose. As a result, the hoses lost flexibility after one year of use. The highest number of heterotrophic bacteria was detected by PCR-denaturing gradient gel electrophoresis in the shower water, and the bacterial DNA concentration was higher when hot water contacted the hose surface. I conclude that the plasticiser was leached from the stiffened hose through a bioaccumulation process.  相似文献   
4.
介绍一种淋浴喷水手柄旋转式抽芯脱模机构及注塑模具设计。结合产品尾端带有圆弧手柄、圆槽头部有侧凹孔以及手柄末端带有外螺纹特征的结构特点,巧妙地在圆槽中央孔位处设计了点浇口+圆片护耳浇注系统,有效地解决了浇口开设困难问题,保证了产品注塑质量。针对产品圆槽部位深管壁位特征,脱模方式采用镶件式推管脱模;弯管处采用电机驱动进行大角度、大行程弯管内型芯脱模;手柄末端外螺纹处则采用哈夫滑块抽芯脱模;有效地降低了模具设计及加工难度;用简单的机构实现了产品的零缺陷自动化模塑生产,有效地保证了产品成型质量,结构设计合理,机构工作稳定、可靠。  相似文献   
5.
We have studied the fabrication of amorphous silicon (a-Si : H) p-i-n solar cells using an ion shower doped n+-layer. The p-i-n cells with ion-doped n+-layer exhibited open-circuit voltage of > 0.8 V, fill factor of > 0.62 and conversion efficiency of > 8.4% when the ion acceleration voltage was between 3 and 7 kV. The a-Si : H p-i-n solar cell fabricated under an optimized ion-doping condition exhibited an open-circuit voltage of 0.84 V, a fill factor of 0.66 and a conversion efficiency of 9.9% which was very similar to those of conventional a-Si : H p-i-n cells fabricated in the same deposition chamber. Therefore, ion shower doping technique can be applied to fabricate large area, high performance a-Si : H p-i-n solar cells.  相似文献   
6.
对全球洗浴及身体护理品、除臭剂进行了概述。对于洗浴和淋浴产品清洗当然是主要目的,但提高沐浴的情趣,并提供全面的居家Spa体验也已成为关键。对于有限的市场增长空间,产品功效或生活方式本身将推动这一市场价值的增长。在浴用品和护体产品中,自有品牌增长强劲。到2012年,预计亚太地区的销售额将超过西欧,成为全球洗浴和身体护理品销售最具价值的地区。  相似文献   
7.
8.
刘群  江仲文 《中华纸业》2007,28(8):77-79
介绍了国外高速造纸机压榨部上的几种新型喷淋设备的原理与结构,及其应用在造纸工业清洁生产和节水方面的新技术。采用合适的喷淋水压和水温、耗水量、喷淋器的喷淋距离和角度、喷淋器的摆动速度等,能明显改进喷淋器的清洁和节水效果。还可以采用抗粘附化学品助剂和中性毛毯,防止毛毯受到污染,从而降低清洗喷淋的耗水量。  相似文献   
9.
本文介绍了1988年投入运行的怀柔广延大气簇射(EAS)阵列的设备构成、工作原理、性能指标及原始数据的记录处理方式。各种检验和首批EAS观测数据表明,该阵列可有效地用于对能量在10~(15)—7×10~(16)eV范围的EAS的探测和研究。  相似文献   
10.
Cosmic ray antiprotons provide an important probe for the study of cosmic-ray propagation in the interstellar space and to investigate the existence of Galactic dark matter. Cosmic rays are hampered by the Moon, therefore a deficit of cosmic rays in its direction is expected (the so-called Moon shadow). The Earth–Moon system acts as a magnetic spectrometer. In fact, due to the geomagnetic field the center of the Moon shifts westward by an amount depending on the primary cosmic ray energy. Paths of primary antiprotons are therefore deflected in an opposite sense in their way to the Earth. This effect allows, in principle, the search of antiparticles in the opposite direction of the observed Moon shadow.The ARGO-YBJ experiment, in stable data taking since November 2007 with an energy threshold of a few 100s of GeV, is observing the Moon shadow with high statistical significance. Using about 1 year data, an upper limit of the flux ratio in the few-TeV energy region is set to a few percent with a confidence level of 90%.  相似文献   
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