风力发电技术经济分析及对策

介绍了中、美等6个国家的电力构成以及世界风能资源的分布,并对世界风能资源经济效益进行了分析,阐述了风力发电的前景,指出了我国风电产业存在的问题,并提出发展我国风电产业的建议:研发大型风电机组,强化环保法规及给予风电产业以优惠政策.     

左思风力之成因初探

西晋诗人左思的诗风在西晋文坛上独树一帜，称之为“左思风力”，前人对此有较多地论述，然而就诗风形成的原因却缺乏深入地探究。本文试图从社会时代背景、家庭因素、性格特征三个方面对此加以分析，旨在能够更好地把握左思其人及其诗风。     

Uncertainty Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.     

福建省耕地流向及其与经济发展的关系

土地利用数量的净变化是土地双向变化的结果。在单一土地利用类型动态度模型基础上利用单一土地利用动态变化辅助方法:列表清单法和单一土地利用动态度双向模型,对福建省及各设区市耕地流向进行分析。并在此基础上,研究了福建省耕地的减少与经济发展的关系,提出福建省耕地保护的措施。     

我国西南地区乡村治理的历史变迁、现状问题与实践路向

现代意义上的乡村治理是通过国家、社会、乡村等的共同作用,来实现对乡村社会动态调控和管理的过程,具有参与主体多元、管理方式民主、运行过程公开等特点。新中国成立以来,西南地区乡村治理共经历了四个各具特色的阶段。新时代的新阶段,这一地区在由脱贫攻坚向乡村振兴转轨的过程中面临着诸多亟待解决的现实问题。在汲取历史经验教训的基础上,针对这些问题可提出若干相应的对策建议。这对在新阶段推进该地区乃至全国的乡村治理现代化,都具有不言而喻的意义和价值。     

Model-based clustering of multivariate skew data with circular components and missing values

Motivated by classification issues that arise in marine studies, we propose a latent-class mixture model for the unsupervised classification of incomplete quadrivariate data with two linear and two circular components. The model integrates bivariate circular densities and bivariate skew normal densities to capture the association between toroidal clusters of bivariate circular observations and planar clusters of bivariate linear observations. Maximum-likelihood estimation of the model is facilitated by an expectation maximization (EM) algorithm that treats unknown class membership and missing values as different sources of incomplete information. The model is exploited on hourly observations of wind speed and direction and wave height and direction to identify a number of sea regimes, which represent specific distributional shapes that the data take under environmental latent conditions.     

穆旦与奥登：历史追问与现实反思——兼与江弱水先生商榷

江弱水在《外国文学评论》上发表的《伪奥登风与非中国性：重估穆旦》指出穆旦诗歌是对奥登诗歌的移译，而非中国性这一特征造成了穆旦诗歌的失败。而文本从选择奥登的原因、伪奥登风的消解、穆旦诗歌中的“非中国性”追问、传统与现代的反思等四个方面探讨和重新考察穆旦诗歌与奥登的关联，进而认为穆旦诗歌的特质与奥登并非密切相关。     

单片机控制器在卷染机中的应用

】将卷染机的控制系统从直流电机拖动、自耦调压器有级调速改造为交流电机拖动和变频器无级调速。通过对调节对象的理论分析,得到了一种新的控制策略,研制出以单片机为核心的控制器,在不使用速度和张力传感器的条件下,控制系统可自动对被染织物进行恒速与恒张力控制,以利于染色质量的稳定和提高。经实际运行表明,该系统运行可靠,节能增效显著。     

Risk Analysis for U.S. Offshore Wind Farms: The Need for an Integrated Approach

Wind power is becoming an increasingly important part of the global energy portfolio, and there is growing interest in developing offshore wind farms in the United States to better utilize this resource. Wind farms have certain environmental benefits, notably near‐zero emissions of greenhouse gases, particulates, and other contaminants of concern. However, there are significant challenges ahead in achieving large‐scale integration of wind power in the United States, particularly offshore wind. Environmental impacts from wind farms are a concern, and these are subject to a number of on‐going studies focused on risks to the environment. However, once a wind farm is built, the farm itself will face a number of risks from a variety of hazards, and managing these risks is critical to the ultimate achievement of long‐term reductions in pollutant emissions from clean energy sources such as wind. No integrated framework currently exists for assessing risks to offshore wind farms in the United States, which poses a challenge for wind farm risk management. In this “Perspective”, we provide an overview of the risks faced by an offshore wind farm, argue that an integrated framework is needed, and give a preliminary starting point for such a framework to illustrate what it might look like. This is not a final framework; substantial work remains. Our intention here is to highlight the research need in this area in the hope of spurring additional research about the risks to wind farms to complement the substantial amount of on‐going research on the risks from wind farms.