火焰原子吸收法测定植物叶片中的微量铅

通过炭化、灰化、混合酸消解和稀硝酸溶解的方法处理样品,利用火焰原子吸收法测定植物叶片中微量铅的含量。待测溶液在0.1～5.0μg.mL-1范围内有很好的线性关系,回归方程为A=0.1053C+0.0071,相关系数为0.9991,检出限为0.006μg.mL-1,特征浓度为0.031μg.mL-1/1%,平均回收率为100.28%。方法适用于测定各种植物叶片中的微量铅含量,可以据此评价环境质量。     

大学主体性的失落与建立现代大学制度

大学主体性的失落是当前大学危机的根源所在,其深层的本质在于学术自由精神的丧失。面对当前大学的危机与困境,学术自由应突破外部的社会限制和内部大学主体自身的限制,应以大学学术自由的理想为指针,结合大学的实际情况,积极构建具有我国特色的现代大学制度。     

Factor analysis for ranked data with application to a job selection attitude survey

Summary.  Factor analysis is a powerful tool to identify the common characteristics among a set of variables that are measured on a continuous scale. In the context of factor analysis for non-continuous-type data, most applications are restricted to item response data only. We extend the factor model to accommodate ranked data. The Monte Carlo expectation–maximization algorithm is used for parameter estimation at which the E-step is implemented via the Gibbs sampler. An analysis based on both complete and incomplete ranked data (e.g. rank the top q out of k items) is considered. Estimation of the factor scores is also discussed. The method proposed is applied to analyse a set of incomplete ranked data that were obtained from a survey that was carried out in GuangZhou, a major city in mainland China, to investigate the factors affecting people's attitude towards choosing jobs.     

新形势下蔬菜学创新型、创业型人才的培养

蔬菜业已经成为当今我国发展最快最活跃的产业之一.论文首次提出了新形势下蔬菜学创新型、创业型人才培养的命题,分析了新形势下蔬菜学创新型、创业型人才培养的历史背景、现状及其必要性,总结了蔬菜学创新型、创业型人才的基本特征,在明确培养目标、实施分层培养、强化实践教学、改进教学方法、提倡教师"导创"、突显教师风范等6个方面论述了蔬菜学创新型、创业型人才培养的着力点,描绘了蔬菜学创新型、创业型人才培养的"三四五实践教学体系"框架图.     

2½‐Year‐Old Children Use Animacy and Syntax to Learn a New Noun

We examine how attention to animacy information may contribute to children's developing knowledge of language. This research extends beyond prior research in that children were shown dynamic events with novel entities, and were asked not only to comprehend sentences but to use sentence structure to infer the meaning of a new word. In a 4 × 3 design, animacy status (e.g., animate agent, inanimate patient) and labeling syntax (agent, patient, nonlabel control) were varied. Across most events, 2 1/2‐year‐old participants responded as if they expected animate entities to be named. However, in a prototypical (animate agent‐inanimate patient) event condition, children responded differentially across different syntactic structures. Thus, the clearest evidence for attention to syntactic cues was found in the prototypical event condition. These results suggest that young children attend to the animacy status of unfamiliar entities, that they have expectations about animacy relations in events, and that these expectations support emerging syntactic knowledge.     

论新时期我国图书馆的服务功能与服务方式

新时期 ,新形势。随着我国社会主义市场经济体制的逐步建立 ,加入 WTO而融入世界经济发展大循环以及知识经济时代的到来 ,我国图书馆面临前所未有的机遇与挑战 ,要求图书馆要适应这种形势的变化 ,提供新的服务功能并采取新的服务方式。     

多媒体英语教学的优势

本文旨在通过提出多媒体教学手段的多种优势以及诸多专家学者的观点,同时谈到笔者在使用多媒体进行外语教学过程中的一些切身体会,进行理论和实践上的论证,以发掘外语教学中利用多媒体教学手段进行创新性“教”与自主性“学”的可能性,并进一步加强学生的自主性学习以及自我调节性学习,使外语教师更加高效地利用多媒体的优势进行理想的外语教学,同时使外语教学手段更加具有开放性和实践性。     

企业的合约经济理论探索和统计检验

对企业本质的认识是微观经济学中的一个重要问题,其对中国的国企改革有着重要意义。本文中,我们对企业的合约本质进行了经济理论探索和统计检验,并突出关注企业的激励合约问题。     

景颇族居住环境及文化分析

影响居住环境的有地理和人文两大因素。该文在分析景颇族居住环境的基础上 ,通过对组成景颇族居住环境的地貌、植物、建筑、小品、装饰、民族风情广场等要素的特色进一步地分析 ,探讨了景颇族文化的内涵。尝试为多元化的现代园林设计提供富有民族特色的素材。