Marsaglia’s lattice test and non-linear congruential pseudo random number generators

Sequences of integers defined by a non-linear recursive congruential pseudo random number generator with prime modulusp and maximal period length are divided into vectors ofd consecutive numbers. The lattice spanned by these vectors is studied. i.e. the minimal lattice which contains all these vectors. It is shown that this lattice coincides with the full integer lattice, at least ford=2 andd=3, i.e. non-linear generators pass Marsaglia’s lattice test at least ford ⩽ 3. For a special class of non-linear generators introduced in Eichenauer and Lehn (1986) it is proved that these generators pass the test even for dimensionsd ⩽ (p − 1)/2. Supported by Deutsche Forschungsgemeinschaft.     

天然气化工利用的经济性分析

文章以完全成本法模型为基准,分析了采用天然气为原料生产合成氨、甲醇、丁辛醇、氢气等产品时盈亏平衡点的天然气价格,提出了降低天然气成本,扩大应用范围的建议.     

日本城市燃气价格规制制度沿革

在100多年的规制过程中，日本的城市燃气价格规制逐步改善了价格与成本之间的对应关系，在罐装液化气、电力的挑战中提高了燃气企业的竞争力。相比于日本，中国城市燃气价格规制制度存在明显的缺陷：仍然按照传统的收益率规制制度确定价格水平；复数两部价格结构严重缺乏效率；绝大多数地区还没有建立系统的负荷调整制度。     

基于GM(1,1)的一种新型嵌套方法在气井产量预测中的应用

针对常规气井产量预测中因忽略气井工艺措施等其它因素影响而将其处理为干扰异常点,造成与气藏排水采气的开发策略不一致的技术难题,结合GM(1,1)模型与灾变模型,提出一种新的嵌套型GM(1,1)模型。该模型通过将气井工艺作为灾变因子,可以更准确地预测气井自然生产模型下的产量变化规律,有效弥补了常规预测法的不足。研究将新模型应用于川西气藏某生产气井单井产量预测,预测结果分别与GM(1,1)预测结果和Arps产量递减预测模型结果进行比较,结果显示新预测模型比GM(1,1)及产量递减预测模型的回归斜率和相关系数更接近1且回归截距更趋近于0,表明新方法的预测精度更加精确,能准确反映气田开发中的产量变化,不失为一种可选的新型产量预测方法。     

生态林业建设的成功之路──关于江西会昌县发展“猪沼果”工程的调查

以“猪、沼、果”为主要模式的生态林业在经济欠发达地区具有广阔的发展前景,在发展模式上,应因地制宜,突出特色,搞好规划;应坚持引导为主,运用为主、效益为主的原则,突出生态这个重点,确保质量。在推广过程中应严把建池质量,推广实用技术,健全服务体系,使整个产业链健康发展,以此促进生态发展,调整林业种植结构,加强农村能源建设,加快农民致富步伐。     

Trade liberalisation and greenhouse gas emissions: the case of dairying in the European Union and New Zealand*

The link between trade and the environment has aroused considerable interest both in terms of the impact of trade liberalisation on the environment, and also the impact of environmental policy on production and trade. Of key environmental concern at present is global warming and its association with greenhouse gas emissions. Agriculture is a sector of the economy that both contributes to, and will be affected by, climate change. This paper models the impact of agricultural trade liberalisation on greenhouse gas emissions from agriculture around the world, focusing particularly on the effects on New Zealand, a small economy highly dependent on agricultural trade. A partial equilibrium agricultural multicountry, multicommodity trade model is used for the analysis, extended to include physical production systems and their greenhouse gas emissions. Two simulations are performed: removal of agricultural policies in the EU and in all OECD countries. The results indicate that although producer returns in New Zealand increase, greenhouse gas emissions also increase significantly. EU producers face lower returns but also lower greenhouse gas emissions.     

Effects of personal characteristics on organizational commitment: evidence from Brazil's oil and gas industry

In 1997, Brazil's major energy company faced a loss of its monopoly as part of the country's structural reform. Many of its employees were recruited by new entrants to the oil and gas industry. In order to retain employees, the company initiated a multiyear planning process which included a redesigned human resource management model oriented to organizational commitment. This study examines the long-term influence of five employee personal characteristics (type of employment, job level, gender, education level and service time) on the affective, normative and continuance components of organizational commitment. The research was conducted in one of the company refinery and involved a questionnaire survey of all employees and interviews with senior managers. It was found that type of employment (company staff or contractor) had the greatest impact on affective and normative commitment, while service time and education level are the most significant contributors to continuance commitment. Gender and job level were found to have limited implication for commitment. The results demonstrate that the company response to structural reform had the long-term positive effect of binding employees to the organization.     

运用瓦斯抽采保障煤矿安全生产

八连城矿是2006年末建成投产,煤层瓦斯含量大,一直困扰安全生产,通过采用煤层瓦斯抽采,解决了瓦斯超限问题,保证了安全生产。因此,瓦斯抽采是煤矿安全生产的保障。     

高含硫气井井筒硫沉积预测新模型

随着元坝高含硫气田逐步投入试采,井筒硫沉积问题受到关注。元坝气田井筒是否存在硫沉积,目前国内外硫沉积预测模型难以确定,本文在前人的基础上,对硫颗粒在气流中的受力进行分析,得到新的临界携硫速度,并将硫的溶解度、压力与温度的耦合,进而提出一个新的硫沉积解析模型,为设计及生产提供理论基础。通过新模型对YB204井实例计算,计算结果合理可靠。     

长输管道打孔盗油气监检测技术现状及展望

目前,长输油气管道面临着严重的打孔盗油气风险,给管道企业带来严重安全隐患、重大经济损失以及恶劣社会影响.综述了国内已有的打孔盗油气监检测技术,研究了管道泄漏监测系统、管道光纤预警系统、内检测技术以及外检测技术的监检测打孔盗油作业的技术原理及在生产应用中存在的不足,并对视频监控系统、无人机巡护以及基于管道电位分析识别焊接类打孔盗油等技术应用前景进行了研究.