SPL(2|1)超代数单参数非齐次微分实现

本文引入了单一实参数，构造了SPL（2｜1）超代数的单参数4维初等表示，获得了SPL（2｜1）超代数单参数齐次微分实现和非齐次微分实现本文的研究结果，对深入研究SPL（2｜1）超代数单参数不可分解表示和不可约表示，构建SPL（2｜1）超对称精确可解模型，具有十分重要的意义。     

Hanging Tough at Our Neighborhood Libraries

The recession in the American economy touches all of us. Budget cuts, layoffs, and reduced service hours may be among the most obvious signs in our neighborhood libraries. Beneath the surface, however, one finds resilience in the face of adversity. At the Information Desk in the Colonial Heights, Elk Grove, and Rancho Cordova branch libraries of the Sacramento Public Library one encounters people who are full of life and vitality as they struggle to find work, fix what is broken, and complete difficult assignments, whether at work, home, or school. Some of their stories are recounted in this article.     

Theft and Its Effects on Our Neighborhood Libraries

Theft is a serious problem in our neighborhood libraries if the results of the survey described in this article are any indication. The Sacramento Public Library had purchased 455 copies of 26 Armed Services Vocational Aptitude Battery (ASVAB) titles. Only 71 were found to be available. Ten of the others had been lost and paid for but the remaining 374 copies had been billed but not paid. This represents a loss of $8,900. Books by the author Zane were also examined. The losses amounted to $6,700. The effects of these losses are discussed. Recommendations for handling high-risk titles and improving the overdue process are suggested.     

弹性结构封闭空间中结构辐射噪声的有源控制(英文)

研究了利用分布式点力源作为次级力源对封闭空腔内的结构辐射噪声进行控制的问题,并对封闭空腔中结构辐射噪声的控制机制进行了分析.建立了包含2块简支弹性板的矩形封闭空腔,并将其作为研究对象.通过对初、次级声场以及结构-声耦合的特性分析,以减小腔内声场的声压级为最优控制目标,分析比较了在不同位置及参数的次级点力激励下腔内声场的声压级响应.仿真结果表明,在2块弹性板上施加联合激振力控制腔内噪声的效果要明显好于激振力只作用在受激弹性板上.