2．4-6．0GHz超宽带低噪声放大器的设计

采用标准0．5μmGaAsPHEMT工艺设计了工作频段在2．4—6GHz可应用于无线局域网（WLAN）和超宽带（UWB）接收机的超宽带低噪声放大器。从宽带电路的选择、高频电路设计的器件选择和电路结构的选择等方面讨论了如何进行超宽带低噪声放大器的设计。结果表明,通过合适的电路结构和器件参数选择,可以采用0．5μmGaAsPHEMT工艺制备满足超宽带系统要求的低噪声放大器。在UWB3．1～5．15GHz低频带内,该LNA增益20．8～21．6dB,噪声系数低于0．9～1．1dB,输入输出驻波比均小于一10dB。在2．4～3GHz频带（涵盖802．11b／g的使用范围）内,该LNA增益20．8～21．5dB,噪声系数低于2dB,输入输出驻波比均小于-10dB。在频带5．2—6GHz,该LNA的噪声系数增大到1．332dB。增益则从21．4dB下降到19．7dB。电路的工作电压为3．3V。     

地方高师院校生物科学专业师范生创新实验能力的提升

当前在国家大力倡导"大众创业、万众创新"的新形势下,着力构建师范生的创新创业体系,提高创新实验能力,是提升学生科研素养和创新创业能力的必然要求,特别是对于地方本科师范院校而言显得尤为必要.通过分析地方高师院校生物科学专业师范生创新实验现状及原因,提出提升师范生创新实验能力的必要性和提升途径,为培养师范生综合能力,促进毕业生就业和深造提供重要参考.     

A partial robust optimization approach to inventory management for the offline-to-online problem under different selling prices

This study examines an optimal inventory strategy when a retailer markets a product at different selling prices through a dual-channel supply chain, comprising an online channel and an offline channel. Using the operating pattern of the offline-to-online (O2O) business model, we develop a partial robust optimization (PRO) model. Then, we provide a closed-form solution when only the mean and standard deviation of the online channel demand distribution is known and the offline channel demand follows a uniform distribution (partial robust). Specifically, owing to the good structural properties of the solution, we obtain a heuristic ordering formula for the general distribution case (i.e., the offline channel demand follows a general distribution). In addition, a series of numerical experiments prove the rationality of our conjecture. Moreover, after comparing our solution with other possible policies, we conclude that the PRO approach improves the performance of incorporating the internet into an existing supply chain and, thus, is able to adjust the level of conservativeness of the solution. Finally, in a degenerated situation, we compare our PRO approach with a combination of information approach. The results show that the PRO approach has more “robust” performance. As a result, a reasonable trade-off between robustness and performance is achieved.     

磁盘表面形貌对润滑剂分布及磁头／磁盘之间润滑剂转移的影响

磁盘表层润滑剂在磁头与磁盘之间转移会影响磁头飞行的稳定性．本文采用改进后的粗粒珠簧模型,运用分子动力学方法,研究了磁盘上类金刚石薄膜（diamondlikecarbon,DLC）层粗糙度和磁盘表面凸起对润滑剂在磁盘表面分布及磁头／磁盘之间润滑剂转移的影响．研究结果表明,DLC层粗糙度对润滑膜平均厚度及磁盘表层粗糙度的影响很小;磁盘表面凸起对磁盘表层润滑剂分布的影响明显．类金刚石薄膜层的粗糙度和磁盘表层凸起均可增加转移到磁头上的润滑剂的体积．但磁盘表层粗糙度对磁头／磁盘之间润滑剂转移量的影响明显低于由磁盘表层凸起导致的磁头／磁盘之间润滑剂的转移量．     

Instruments of Music,Instruments of Science: Hermann von Helmholtz's Musical Practices,his Classicism,and his Beethoven Sonata

The young Hermann Helmholtz, in an 1838 letter home, declared that he always appreciated music much more when he played it for himself. Though a frequent concert-goer, and celebrated for his highly influential 1863 work on the physiological basis of music theory, Die Lehre von den Tonempfindungen, it is likely that Helmholtz's enduring engagement with music began with his initial, personal experience of playing music for himself. I develop this idea, shifting the discussion of Helmholtz's work on sound sensation back to its origins, and examine the role of his material interaction with musical instruments and music itself. In his sound sensation studies, Helmholtz understood sound as an external, physical object. But Helmholtz also conceived of sound in musical terms. Further, Helmholtz's particular musical tastes as well as his deeply personal interaction with musical instruments allowed him to reconcile his conception of sound as physical object with his conception of sound as music. Helmholtz's physiological theory of sound sensation was both the product of and constitutive of how he heard and created sound. I argue that Helmholtz himself was the embodied reconciliation of his physiological theory of sound sensation and his belief that musical aesthetics were historically and culturally contingent.     

镉污染土壤的植物修复研究进展与展望

近年来,重金属镉(Cd)及其复合污染问题越来越受到人们的关注.Cd污染土壤的植物修复技术因其具有治理成本的低廉性、环境美学的兼容性和治理过程的原位性等优势,随之成为具有广泛应用前景的技术.本文概述了Cd超积累植物的筛选及耐性机理与修复潜力的评价等方面的国内外进展,总结了Cd-重金属复合污染土壤、Cd-有机物复合污染土壤的植物修复相关的重要工作,着重评述了Cd复合污染土壤的化学强化、农业生态强化及其它方法的研发现状,展望了这一领域今后的重点研究内容和重要发展方向.     

英语专业开设专门用途英语的可行性研究

分析了给大学四年级英语专业学生开设专门用途英语(ESP)——"汽车英语"课程的可行性。ESP课程的教学材料从现有的资料中按照教学要求、目的选取。经过17周的教学,对学生掌握的汽车英语知识、翻译能力进行测试。结果表明,学生在学习课文和翻译课文过程中,能够逐渐掌握一些基本的汽车知识,能够较通顺地翻译汽车技术方面的文章。对教学材料的分析表明,在一篇技术文章中,技术词汇占的比例很小,因此,给英语专业学生开设汽车英语课程是可行的。     

集值离散动力系统的拓扑遍历性、拓扑熵与混沌

设(X,d)为紧致度量空间, f: X→X连续, (K(X),H)是 X所有非空紧致子集构成的紧致度量空间. 通过研究点运动与点集运动的关系, 证明了集值映射拓扑遍历 与f拓扑双重遍历等价并构造一个零拓扑熵且不具有任何混沌性质的紧致系统, 其诱导的集值映射有无穷拓扑熵且分布混沌, 表明集值离散动力系统的拓扑复杂性可以远远大于原系统.     

基于Vague集的本科生科技创新工程项目的评优方法

本科生科技创新工程可以激发大学生参与科研活动的热情. 提出了基于Vague集的科技创新工程项目的评优方法,该方法可以克服加权平均方法的一些缺陷. 通过实例说明了该方法的有效性.     

地球静止卫星位置自主确定方法与仿真研究

给出了利用星敏感器测量信息自主确定地球静止卫星位置的方法,利用不同精度的星敏感器测量数据和不同控制精度的卫星姿态测量数据,可以直接计算卫星位置.同时又对测量数据应用卡尔曼滤波进行卫星位置计算仿真,比较两种处理结果的精度.仿真结果表明,提出的方法可以实时自主获取静止卫星的轨道位置,满足静止卫星定点的不同精度需求.