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81.
In this study the routing problem for unit-load automated storage and retrieval systems (AS/RSs) with separate input and output points is considered under the shared storage policy. The problem is to find an optimal travel route of a S/R (storage and retrieval) machine to process given storage and retrieval requests so that the total travel time is minimised, where the input and output points are possibly separate and the shared storage policy is assumed. We first give two types of formulations as 0–1 integer linear programming problems corresponding to two types of dwell point settings: the dwell point is the input point and the output point. Next, we propose a simple but efficient exact solution algorithm based on the formulations that utilises a general MILP (Mixed Integer Linear Programming) solver. Its efficiency is then demonstrated by numerical experiments. Instances with 400 items (200 for each storage and retrieval) are solved within 100 s. 相似文献
82.
The characteristics of recycling gas drilling
technology 总被引:2,自引:0,他引:2
Recycling gas drilling is a new drilling technology. This paper can be divided into three parts,
with the purpose of introducing and analyzing the characteristics of this new technology. First, the major
equipment characteristic of this technology was introduced. Secondly, compared with conventional gas
drilling, Angel’s model was used to analyze the wellbore flow characteristics. Due to the closed loop
and the effect of back pressure caused by the equipment, the gas flow rate decreases dramatically during
drilling. Apart from this, it is also found that the kinetic energy at the casing shoe is always smaller than
that at the top of the collar. The proposing of the drilling limit concept points out the basic difference
between the two gas drilling technologies. Lastly, according to the results of the theoretical analysis,
gas supplement operations for the wellbore must be conducted. Thus, two gas supplement schemes are
presented in this paper, to provide some guidance for field operations. 相似文献
83.
马哈鱼皮制作丰满型皮革工艺的研究 总被引:1,自引:1,他引:1
前言马哈鱼即三文鱼也称虹鳟鱼,是优质高产的淡水养殖鱼,原产于美洲西岸夏斯达山麓的河川中,我国黑龙江中下游盛产该品种鱼。近几年黑龙江许多地区开始大规模人工养殖马哈鱼并获得成功,马哈鱼属硬骨鱼纲,真骨总目鲑科,是冷水鱼类。马哈鱼皮具有独特的自然花纹,人工难以模仿,美国、加拿大等国家已开发出色彩艳丽,具有不同质感的鱼皮革制品,并风靡整个欧洲市场及日本市场。我省的鄂伦春族也素有用马哈鱼皮制作民族服装和饰品的风俗。因此开发这一资源,使其由资源优势转化为产业优势,弘扬民族风俗传统,美化人们的物质文化生活,具有非常现实的意… 相似文献
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87.
Takayama H Takahashi S Moriya T Osada H Iwabuchi Y Kanoh N 《Chembiochem : a European journal of chemical biology》2011,12(18):2748-2752
Seeing below the surface: A small-molecule droplet array platform on an NADH-immobilized solid surface and a biotinylated acetophenone derivative were developed to identify the substrate candidates for soluble P450 enzymes of interest. This methodology is thought to be easily applicable to other class I P450 systems, including those that use NADPH as cofactor. 相似文献
88.
Pin-on-disk type unidirectional sliding wear experiments for an Al-Si alloy impregnated graphite composite (pin) in contact with a bearing steel (disk) were conducted at various contact loads in wet and dry air to investigate the wear behaviors in detail. The pin-lifting phenomena of the composite as observed. The height was constant at lower loads and increased with load. The entrance of wear particles into the contacting surfaces brought about the pin lifting. Mixtures of graphite powder and wear particles adhered to the sliding surface of the bearing steel, resulting in the formation of wide, compacted surface films. The mean thickness of the films increased with load to a few micrometers. The composite exhibited better wear resistance than the matrices in wet air and the wear rate decreased especially at high loads. The wide, compacted films together with the pin-lifting phenomena prevent metal-to-metal contact, achieving a good anti-wear condition. On the other hand, the surface films that adhere in a scaled fashion in dry air have little wear reduction effect. 相似文献
89.
本文详细地讨论了信源编码的原理,介绍了最优量化的方法以及自适应量化编码的原理。本文还给出一个自适应量化编码的实例。 相似文献
90.