海上地震采集减少潮流影响的方法研究

海上地震采集作业中潮流的影响主要表现在影响海底电缆的铺放、海底电缆在海底位置的移动、拖缆的羽角大小及变化、拖缆采集的面元匹配、海底电缆、拖缆采集资料的信噪比等。通过研究潮流对地震采集作业的影响机制和规律,渤海海域地震采集作业中的实际应用,展示了多种控制潮流影响的方法和手段,通过在电缆上配置横向控制器能够将补线率降低5%~10%。实践证明,这些方法的综合利用能够大幅减少潮流对地震采集的影响,提高地震资料的品质。     

拖缆高密度采集施工的关键因素及质量控制

高密度三维地震勘探应用越来越广泛,海上拖缆高密度三维地震资料采集需要拓宽震源频带和提高空间及时间采样率。结合渤海油田A区块拖缆高密度采集施工的实例,总结了海上拖缆高密度三维地震采集施工的关键因素,即宽频带的空气枪震源配置、电缆深度控制、电缆间距控制、全网高精度声学定位、电缆噪音压制和精确的校正技术。拖缆高密度采集的资料分辨率有较大提高,效果较好,对各种方式的海上拖缆采集具有指导意义和借鉴作用。     

地震工程项目之质量与工期探析

针对四川盆地地震工程项目管理中存在的质量问题，从地震资料采集质量、处理质量和解释质量3个方面进行了分析．提出了相应的改进措施．同时对地震工程项目工期延迟的原因厦改进措施进行了讨论。     

海底电缆工程造价影响因素分析

近年来海底电缆工程数量及建设规模不断增加,由于海底电缆工程建设受诸多条件限制,其造价管理难度较大。梳理海底电缆工程施工过程,分析影响海底电缆工程造价的主要因素,运用层次分析法和变异系数法对影响因素进行深入研究,可明确电缆敷设的距离和建设场地征用及清理费对海底电缆工程造价影响最大,应对这些费用进行严格管控。     

强化地震检波器应用的标准化管理水平进一步提高地震勘探采集质量的可靠性

地震勘探是对地层的非电量电测．地震检波器是地震勘探采集的信号源头,严格地讲地震数据的采集过程就是地层声波传导反射性能的计量测试和记录过程。地震检波器相当于一次仪表。将机械震动性质的地震波转换为相应的电的波动,数字地震仪相当于二次仪表,将表征地震波信息的电的波动进行量化和存储．地震检波器与数字地震仪共同组成一个完整的地震勘探数据采集系统。地震检波器是地震数据采集第一道工序,一旦地震检波器采集的数据失误,将造成事后无法弥补的误差。因此国内外的各个地震勘探项目技术要求和甲方管理,都对地震检波器的校准和质量监控十分重视。     

海底电缆铺设转盘研究

海洋资源已经成为我国越来越重要的资源，海底电缆作为非常重要的信号和动力等传输工具，在海洋资源的开发过程中发挥着举足轻重的作用。现阶段如何高效安全的进行海底店电缆的铺设，是需要重点研究解决的问题。文章通过调研分析，结合海底管道铺设的现状，开展了高效的海底电缆铺设转盘的设计研究，通过对于提高海底电缆的效率和安全性具有重要的意义。     

河南油田首支整编制地震队赴阿曼

近日，河南油田地调处隆重举行赴阿曼地震勘探职工欢送大会。河南油田地调处2227地震队本次承担的阿曼36／38区块地震采集工程为中国石化注册的100％风险勘探区块。据悉第一期部署1300km二维地震采集工程，由地调处独立负责生产组织实施。这标志着河南油田第一支整编制地震队进入国际勘探市场。     

谈浅海海底电缆施工检验

随着我国浅海地区石油资源开发规模的扩大，在我国渤海湾浅海地区固定式采油平台越建越多，需要敷设的海底电缆也越来越多。但目前从整体看来施工人员的质量意识普遍不高，安全意识不强，使海底电缆在运行中存在一些安全隐患问题。因此，加强海底电缆的施工质量管理，提高施工人员的安全隐患意识，以提高海缆的施工质量，确保海底电缆安全运行，是当务之急。     

海底电缆抽拉方法及平台改造分析

随着海洋石油开发的发展,海底电缆在海洋平台之间电力供应、生产通讯及水下生产系统控制等方面,扮演着越来越重要的角色。在海底电缆铺设的起始和终止阶段,通常采用绞车等装置将电缆从海底抽拉至平台上后,接入电缆接线箱。抽拉之前,根据规划好的钢丝绳路由及绞车、滑轮等设备位置,通过计算分析,对平台结构进行局部改造,加强薄弱部位,使其满足抽拉强度要求。本文通过实际项目工程,详细介绍了海底电缆抽拉过程、二次抽拉方法及平台布置方案,并利用SACS对设计方案进行强度校核,为以后类似项目的实施提供技术指导和经验。     

井间地震VSP技术在渤海油田的首次应用

井间地震是通过采集接收井和震源井之间的地震波信息,得到高分辨率地震成像剖面的一种VSP技术。通过特殊的震源、检波器布放方式,很大程度上消除了地表因素对地震作业的影响,实现了高频带采集。文章详细介绍了该种方法在海上平台的实施过程,并通过具体成功案例论证实施的可行性。该案例在海洋石油自营区块中属首次作业,为井间地震VSP在海上平台施工作业提供了值得借鉴的新思路。     

混凝土梁板裂缝的超声检测与灌胶修补技术

本文提出了结构混凝土裂缝超声检测的实用步骤及灌胶补强处理的实用方法。通过实验和工地实际使用表明 ,这些步骤和方法效果良好 ,完全能满足实际施工要求     

Toll-free numbers: Demand,property rights,and public policy

The demand for Toll Free Numbers (TFNs) languished from 2000 to 2008; however recent growth in demand caused the FCC to open a new toll-free code (855) with the possibility of new code openings in the next three years. The analysis here indicates the demand for TFNs is highly inelastic (the coefficient for own price elasticity for TFNs is approximately −0.04). This has implications for concerns regarding future exhaust of toll-free codes and the price structure for recovery of SMS/800's costs. This article considers the effects of the limited property rights for TFN, and welfare implications of gray markets for vanity TFNs. The FCC's allocation mechanism for new 855 codes is considered and whether other allocation mechanisms, such as auctions, could be welfare superior.     

Fashion retail forecasting by evolutionary neural networks

Recent literature on nonlinear models has shown that neural networks are versatile tools for forecasting. However, the search for an ideal network structure is a complex task. Evolutionary computation is a promising global search approach for feature and model selection. In this paper, an evolutionary computation approach is proposed in searching for the ideal network structure for a forecasting system. Two years’ apparel sales data are used in the analysis. The optimized neural networks structure for the forecasting of apparel sales is developed. The performances of the models are compared with the basic fully connected neural networks and the traditional forecasting models. We find that the proposed algorithms are useful for fashion retail forecasting, and the performance of it is better than the traditional SARIMA model for products with features of low demand uncertainty and weak seasonal trends. It is applicable for fashion retailers to produce short-term retail forecasting for apparels, which share these features.     

Brand-specific tastes for quality

This paper develops a model of nonlinear pricing with competition. The novel element is that each consumer's willingness to pay for quality is private information and is allowed to differ across brands. The consumer's preferences are represented by a multidimensional type containing the marginal value of quality for different products. Buyers with high willingness to pay for quality also display strong preferences for particular brands, and require higher discounts in order to switch away from their favorite product. Therefore, competition is fiercer for buyers with lower tastes for quality, and hence more elastic demands. This is in sharp contrast to earlier models in which competition is fiercer for higher-taste, more valuable buyers. In equilibrium, firms either compete intensively for the entire market (providing strictly positive rents to all consumers) or shut down the least profitable segment of the market. Quality levels are distorted downwards for all buyers, except for those with the highest type. The number of competing firms and the degree of correlation across brand preferences enhance the efficiency of the allocation.     

2006-2008年输变电工程场地建设清理及补偿费用趋势分析

随着经济社会的发展,土地资源日益稀缺,电网工程建设用地清理及补偿工作难度日益加大,费用不断增加,并逐渐成为电网工程造价上涨的主要因素。通过分析2006-2008年输变电工程场地建设清理及补偿费用的变化,揭示输变电工程建设场地费用变化情况及趋势,分析了其主要影响因素。     

Comparing consumer preferences for color and nutritional quality in maize: Application of a semi-double-bound logistic model on urban consumers in Kenya

Consumer preferences for white maize in East and Southern Africa concerns developers of maize biofortified with provitamin A carotenoids, since carotenoids impart a yellow or orange coloration. Urban consumers’ willingness to pay (WTP) for yellow maize was estimated, using a semi-double-bounded logistic model, based on a survey of 600 maize consumers in Nairobi, Kenya, at posho mills, kiosks and supermarkets. Consumers showed a strong preference for white maize. Only a minority would buy yellow maize at the same price as white maize, and fewer consumers in the posho mills (24%) and kiosks (19%) than in the supermarkets (34%) would do so. On average, consumers need a price discount of 37% to accept yellow maize. This discount was less at the posho mills (35%) and kiosks (37%) than in the supermarkets (48%). Most respondents (76%) were aware of the existence of fortified meal and the generally showed an interest. The average premium for fortified maize was much less than the discount for yellow: 5.9% for those aware and 7.4% for those unaware. Consumer preferences were influenced by socioeconomic factors such as gender, education, income and ethnic background. Women have a stronger preference for both white maize and fortified maize than men, and consumers with more education have a stronger preference for white. Income decreases the WTP for yellow maize as well as the price elasticity, but increases the WTP for fortified maize. Consumers originating from Western Kenya have a lower preference for white, while those from Central Kenya had a stronger preference for fortified maize.     

Willingness to pay for the “Green Food” in China

With use of payment card survey data of willingness to pay (WTP) for the “Green Food”, a unique food certification in China, this study finds that age and income are important for the WTP for the Green Food in China. There are structural differences in consumer preference for Green Food between the large city and the small county. Consumers in China, on average, are willing to pay 47% more for Green vegetables and 40% more for Green meat than for their conventional counterparts. Compared with the real markets and the previous studies, our results are very consistent and reliable.     

Double-fortified salt reduces anemia,benefit:cost ratio is modestly favorable

Iron deficiency is very widespread, with adverse consequences for health and cognition. Iron supplementation is not popular for long-term use, and cereal fortification is not feasible where milling occurs locally. Double-fortified salt (DFS: using both iron and iodine) is an alternative. The study undertakes a literature survey to find the effect of DFS on hemoglobin, and then uses a previous algorithm to make calculations for India. The benefit:cost ratio was estimated as 2.4:1 if only the benefits to children and women were included, and between 4:1 and 5:1 if anemia levels for men also decreased. This is just a little lower than the median ratio estimated for iron fortification of cereal staples (6.7:1), for home fortification for children less than two (37:1), and for biofortification – breeding for high iron – of cereals (high, but no exact figure available). Double-fortified salt is therefore a good alternative for improving iron status in populations where fortification of other staple foods does not achieve desired coverage.     

300MW火电机组循环水系统最优运行方式的研究

从凝汽器最佳真空的原理入手,分析探讨了目前火电厂循环水系统的运行优化问题.对水量不连续变化的单元制循环水系统提出了一种离散优化模型,该模型以等效益点迭代计算来决定泵组切换时的临界工况.以十里泉电厂300MW机组为例,利用本模型对循环水系统进行了运行方式的优化研究,确定了机组在不同循环水温、不同负荷最经济的循环水泵运行编组方式,编制了循环水系统最优化运行工况图,为运行中实现指导循环泵的科学经济调度提供了量的依据.效益分析表明,对于300MW机组,循环水系统离散优化可使电厂标准煤耗降低0.5～0.7g/kW.h.实践表明该方法简便易行,运行可操作性强,节能效果明显,而且无须增加额外的支出,有很好的推广价值.     

电力工程招投标复合标底的应用分析

介绍了目前在电力工程招投标中常用的几种投标报价标底形式,分析了电力工程招投标中复合标底的应用特点和风险,列举了复合标底的计算方法,提出了优化复合标底计算的建议,以期对电力工程招投标工作有所助益。