首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 562 毫秒
1.
三次采油技术的研究现状   总被引:2,自引:0,他引:2  
本文主要介绍了三次采油技术产生的背景,现有的主要驱油方法及其驱油机理,总结了各类三次驱油中主要的驱油剂,并对未来的三次采油技术发展趋势和亟待解决的问题进行了展望.  相似文献   

2.
光皮树是山茱萸科株木属落叶乔木,分布于黄河流域以南,是高产优质的食用油料树种,栽后3。5年可开花结实。大树每株年产干果50公斤以上,干果含油率33%~36%,出油率25%~30%;其油为一级优质食用油,长期食用光皮树油治疗高血脂症有效率达93.3%,其中降低胆固醇的有效率达100%。下面介绍光皮树的栽培技术,供参考。  相似文献   

3.
光突发交换(OBS)技术集成光电路交换和光分组交换的优势,能满足现有大容量、高速率的多媒体信息交换与传输,将成为下一代光IP骨干网的核心技术。本文详细论述了OBS网络中的关键技术———突发分组的组装技术的各种策略与实现方式,指出具有良好QoS保证又可降低可操控性的突发组装策略将成为最佳选择。  相似文献   

4.
本文介绍等离子无油点火技术的工作原理;阐述了国内外的研究现状以及应用情况;提出了现在的等离子无油点火技术主要分为热裂解型等离子无油点火技术和直燃型等离子无油点火技术,同时提出开发针对贫煤和无烟煤的等离子无油点火技术的应用空间;并对产生的经济和社会效益进行分析;最后指出在应用中出现的问题以及相应的解决方法。  相似文献   

5.
为适应缝制效率不断提高,缝机高速化水平也在不断提升;高速化带来的润滑问题促使了缝制设备制造业无油技术的产生和飞速发展;高速、无油、节能、环保成为缝机技术发展方向。  相似文献   

6.
总结了毫米波、亚毫米波频段的准光功率合成技术的研究进展,介绍了准光功率合成技术早期的研究成果。重点讨论了近期提出的引入全息技术的准光功率合成技术。全息技术有效地解决了器件小型化和散热间的矛盾,能满足未来更高频率的输出功率和效率的要求。  相似文献   

7.
简要介绍光波分复用系统的基本原理、基本结构、关键技术、功能配置和技术特点,说明光波分复用wdm系统在今后光通信发展中的重要性.  相似文献   

8.
《化工科技市场》2005,28(8):64-64
日前,中山市中侨涂料粘胶有限公司的重点项目,丌发时间历时两年的水性UV树脂终于宣告研制成功,该树脂成膜透明柔软,光固化速度快,耐摩擦力强,对金属“铝”纸等的表面有极佳的附着力,无毒无味,环保不燃,固含量78%,外观仝透明至微黄粘稠液体状,使用时不再需要添加单体和引发剂,粘度调整可用水或乙醇任意稀释,适合深加工成水性UV光油,水性UV柔印油墨,  相似文献   

9.
微油点火和超低负荷稳燃技术是用少量的油强化燃烧,通过专门的燃烧器,点燃大量的煤粉,从而达到以煤代油启动锅炉的目的;另外在锅炉低负荷时,可以将该燃烧器投入,用少量的油实现锅炉的超低负荷稳燃.该技术可以大幅度减少火力发电厂点火启动和助燃用油,节能环保降低发电成本,为电力企业创造巨大的经济、社会效益.本文阐述了微油点火在火电厂的原理,调试运行及步骤方法,具有借鉴意义  相似文献   

10.
RFoG技术在HFC网络双向改造中存在明显的优势,越来越多的运营商采用RFoG组网方案,但是RFoG的射频光网络单元由于光突发模式采用电平控制ONU的开通与关断,造成实现困难。为此,给出了一种基于同步传输的射频光网络单元设计方法,将回传信号数字化,采用和CMTS相同的时分复用技术(TDMA)来控制ONU反向光发射的“突发”,从而达到在任一给定的时点只允许一个ONU与CMTS头端保持通信,以弥补其不足。  相似文献   

11.
王金银 《化工科技市场》2002,25(1):24-26,72
本文选用醇酸树脂、各种颜料以及多种助剂制备成柔和清漆的乙组分,与甲组分(固化剂)按一定比例施工,并介绍了双组分醇酸聚漆的应用状况,指出了醇酸聚酯漆的市场状况及具有良好的市场前景。  相似文献   

12.
偏苯三酸酐是一种重要的有机化工原料,主要用于生产粉末涂料、环氧树脂固化剂、偏苯三酸酯类增塑剂、聚酰亚胺绝缘漆等,其生产方法主要有硝酸氧化法、液相空气氧化法和间二甲苯法3种。2008年世界偏苯三酸酐的总生产能力约为31.0万t/a,消费量约为23.0万。中国偏苯三酸酐的生产能力约为10.5万t/a,消费量约为3.3万t/a。预计到2010年中国偏苯三酸酐的消费量将达到约4.1万t,产能已经严重过剩,切不可盲目扩建产能。  相似文献   

13.
This research seeks to identify variables that should be related to venture performance. It is hypothesized that both market attractiveness and resource-based capabilities are directly related to new venture performance. In addition, specific resource-based capabilities are hypothesized to be directly related to the competitive strategies chosen by a firm. Finally, the “fit” between strategies and resource-based capabilities is hypothesized to be related to venture performance.The sample consisted of all manufacturing businesses (SIC codes 20–39) started or reorganized in the corporate form between 1980 and 1991 in nine counties in northwestern Pennsylvania, as identified by a major marketing research service. Of the 800 companies surveyed, completed questionnaires were returned for 155, representing a 19% response rate. The 155 responding companies had a median age of 5 years with a median of 15 employees. The major products of companies in the sample included flour, lumber, household and office furniture, plastic containers, tools and dies, ready mixed concrete, pipe fittings, measuring devices, paint and varnish, machine tools, electroplate, carbon and graphite composite products, plastic laminated products, circuit boards, electronic components, and parts for internal combustion engines.In general, the results confirm the validity of the measures of environmental and organizational characteristics as we have adapted them for new ventures. As hypothesized, perceived market attractiveness and the overall abundance of resource-based capabilities were significantly related to venture performance. Also, in two of three cases, the evidence suggests that specific resource-based capabilities are related to the firm's stated competitive strategies. Finally, although the relationship between “fit” and performance is not supported in all cases, the performance of the emerging manufacturing ventures included in this sample appears to be enhanced when resource-based capabilities are supportive of a cost leadership strategy and when firms seeking to differentiate based on product and service quality have the resource-based capabilities to support that strategy. The results of this emerging research stream will make an important contribution to our understanding of the factors that impact firm performance. For scholars the results provide additional information needed to develop comprehensive new venture performance models. A clear understanding of the factors that have a strong influence on venture performance will enable practitioners to better identify viable business opportunities and academicians to provide potential business founders with tools to help them recognize opportunity. In addition, the identification of appropriate levels of abstraction will provide building blocks for future research that seeks to integrate environmental and firm-level constructs.  相似文献   

14.
《Business History》2012,54(7):1152-1177
Economic theories of commercial nonprofits and mutuals usually emphasise the advantages of such organisational forms in reducing agency and monitoring costs in markets that suffer from information asymmetries in exchanges between firms and their customers. This article examines the ability of such transaction cost theories to account for historical variations in the ownership and governance of firms in the US personal finance industry between the early nineteenth century and the Great Depression. It focuses, in particular, on mutual savings banks and their role in the development of the intermediated market for savings accounts. While I find some evidence in support of transaction cost theories of organisational form, I also find that entrepreneurial and socio-political factors played crucial roles in the choice of ownership and governance structures; mutual savings banks predominated in the early years of the industry because the form offered entrepreneurial advantages over investor-owned corporations and because in some states they benefitted from regulatory and political advantages that joint-stock companies lacked. Their relative decline by the early twentieth century was the result of increasing competition in the market for savings deposits, the loosening of regulatory barriers to entry, and changes in public policy that reduced the transaction, innovation and regulatory advantages that the mutual savings bank form had once held. The article draws out the theoretical implications for our understanding of the historical role of nonprofit and mutual firms.  相似文献   

15.
我国“独立保函司法解释”适应了法律规则和法学理论发展的国际性、时代性需求,但从其出台至今的周期性司法实践看来,司法机关对保函的独立性认定问题,仍存在一定的认知偏差,各地法院的判决标准分歧明显。独立担保制度产生于欧美发达国家,早期独立担保项下规则适用的基本向度均与欧美各国在不同历史时期下的商事发展需求相关。在资本主义目的因子的驱动下,以美国为代表的英美法和以法国为代表的大陆法国家对独立保函的独立性认定标准各异。中国司法对独立保函的独立性认定思路应以“一带一路”战略需求为导向,参见域外“重实质轻形式”的历史性成果,对“单据”“基础合同”“从属性条款”等争议问题明确定位,采用宽松认定的基本态度。  相似文献   

16.
Abstract

This appraisal considers the role and impact of vocational education and training (VET) in Australia and New Zealand, and suggests directions such policy might take in other Asia-Pacific countries. It identifies key issues and constraints in making VET more responsive to emerging labour market needs in the region as an important factor in sustaining high economic growth. It focuses on the way in which the demands of the government, industry, trainees, and, in particular, shifts in political ideology that have influenced the education and training sectors in both countries. It addresses points of specific relevance for the delivery of VET in the broader Asia-Pacific context and concludes with a consideration of lessons and experiences of Australia and New Zealand with VET that may hold for other countries in the region in formulating priorities and implementing strategies in meeting their current and emerging needs for skills development.  相似文献   

17.
In many countries, changes in the pattern of working lives and ageing of the population increases the need for professional cleaning in private domestic homes. The objective of this study was to obtain basic knowledge concerning professional home cleaning. The study consisted of two parts. First, cleanability of surfaces contaminated with microbiological and organic soils was examined in the laboratory using cleaning cloths, detergents and rapid detection methods with potential for use in conjunction with professional cleaning in private homes. Second, hygienic conditions in three households were screened using the same rapid detection methods as in the laboratory experiments. According to the laboratory study, the cleaning efficiency of the non‐woven cloth was clearly poorer than that of the cleaning cloths containing microfibers. There were differences between the efficacy of the cleaning agents in removal of protein and microbiological soils. Despite the differences between surface topography observed with scanning electron microscopy, differences between the cleanability of the three examined surface materials (steel and two plastic surfaces) were small. In hygiene monitoring, the highest levels of total aerobic bacterial counts were detected in the plughole of the sink, on the eating table in kitchens and along the edge of the toilet washbowl and the cover of toilet seats. Low amounts of Enterobacteriaceae indicating faecal contamination were detected in the toilet and bathroom after cleaning. Moulds were not detected in any of the three households, and the amounts of yeasts were low. Detection methods, microbiological dipslides and the protein test, were well suited to the laboratory study. Furthermore, they complemented each other in the hygiene monitoring. The information obtained will be used for development of better practices in professional home cleaning. Good quality management in professional home cleaning and the cleanliness of surfaces in homes are important factors affecting comfort and safety.  相似文献   

18.
Guided by the theory of trust transfer, the present study sheds new insights on the role of trust in manufacturer brand on trust in private label brand (PLB), perceived risk and willingness to buy (WTB). The moderating role of grocery store format between trust in manufacturer brand, trust in PLB and WTB is also examined. The empirical data were collected by means of a written survey instrument from consumers. The hypotheses were analyzed with maximum-likelihood estimation. The results revealed the positive influence of perceived manufacturer brand quality on trust in manufacturer brand and trust in PLB. The positive linkage between trust in manufacturer brand and trust in PLB is also supported. The negative influence of trust in manufacturer brand and trust in PLB on perceived risk was revealed and the positive impact of trust in manufacturer brand and trust in PLB on WTB was also confirmed. The findings provide support for the negative link between perceived risk and WTB. Additionally, perceived risk partially mediates the relationships between trust in manufacturer brand, trust in PLB and WTB. Furthermore, store format moderates the impact of trust in manufacturer brand and trust in PLB on WTB. Theoretical and managerial implications are presented based of the research findings.  相似文献   

19.
This paper examines the hypothesis that the boom in dollar credit in emerging market economies (EMEs) is associated with an excessively low interest rate in the US. For this purpose, we use a multivariate correlated unobserved component model that allows for correlation between shocks to dollar credit, cross‐border interest rate gaps—measured as the difference between emerging market interest rate and the US interest rate, and dollar index both in the short run and in the long run. In addition, it also provides us a quantitative estimate of the permanent and transitory movements in dollar credit in EMEs, interest rate gaps and dollar index. The results from this model do suggest that a temporary increase in interest rate gaps and decline in the dollar index are associated with a temporary increase in the dollar credit in EMEs with a very high degree of correlation. The estimate of the cyclical component of the dollar credit in EMEs from our model captures the recent boom and bust in this market and compares favourably to alternative trend–cycle decomposition methods.  相似文献   

20.
The aim of this paper is to examine the application of the European Foundation for Quality Management model for self-assessment as a means to introduce changes in management in services in higher education institutions (HEIs) in Spain and in Jordan. This paper uses the case study methodology on eight administrative services in a public university in Spain and seven university services in two Jordanian universities, a public and a private institution. The findings show the steps that an administrative service may follow in order to apply the questionnaire approach successfully in a reform process, the difficulties, the benefits and the success factors in both countries and the consequences of the changes introduced. The study provides lessons for decision makers and managers from other universities in developed and developing countries, who wish to introduce the practice of quality management by creative means. This paper extends knowledge on self-assessment (steps, difficulties, benefits, success factors and changes in management) to services in HEIs.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号