AGRIN混合光学系统设计

轴向梯度折射率(AGRIN)透镜是一种有望用来替代非球面,并在成像时优于非球面的一种方法.综述了AGRIN材料的发展历史,现状及其在镜头设计中的应用,简述AGRIN材料在光学设计中的应用和它与非球面相比的优点,探讨AGRIN材料的制造问题.发现使用AGRIN材料,不仅会使光学系统成像质量有所提高,而且在制造和测试上都有很大的优势.最后以设计一个焦距125 mm、F/4、视场25°,适用于DALSA全帧28M像素大幅面CCD的航测数字相机镜头为例,把原来的11片全球面镜头,利用2片AGRIN透镜,在保持像质不变的情况下减少到8片,而且像质均匀性和镜头结构更加合理.     

Developing nanotechnology in Latin America

This article investigates the development of nanotechnology in Latin America with a particular focus on Argentina, Brazil, Chile, and Uruguay. Based on data for nanotechnology research publications and patents and suggesting a framework for analyzing the development of R&D networks, we identify three potential strategies of nanotechnology research collaboration. Then, we seek to identify the balance of emphasis upon each of the three strategies by mapping the current research profile of those four countries. In general, we find that they are implementing policies and programs to develop nanotechnologies but differ in their collaboration strategies, institutional involvement, and level of development. On the other hand, we find that they coincide in having a modest industry participation in research and a low level of commercialization of nanotechnologies.

平衡设计多向分类多元重复测量模型的Wilks检验

对平衡设计多向分类多元重复测量模型,利用极大似然比方法,推导了对各单个固定效应分别进行检验的Wilks型检验规则.并推导了对多个固定效应进行同时检验的检验规则.推导了非中心分布的参数与原始参数和样本容量的关系.     

关于“数学建模”课程教学现状的调查与分析

根据问卷调查和深度访问获得的第一手资料,对当前我国"数学建模"课程教学现状作了总结和分析,并就该课程教学中存在的几个有共性的问题提出自己的意见和建议.     

国内化学教育领域调查研究的内容分析与品质考察

选取化学教育领域核心期刊《化学教育》和《化学教学》2011-2016年的180篇调查研究类文献为样本,分析了研究的现状和趋势,并运用“调查类文献品质考察工具”对调查类文献品质进行了考察。研究发现,调查类研究数量呈下降趋势;研究主题以化学学习、教师教育、化学教学为主;调查对象主要是中学生和在职教师;作者群体约半数来自高等学校。研究品质方面,虽然研究品质逐年提高,但整体研究品质仍不容乐观,主要问题在于缺乏信度和效度的直接证据,数据分析处理方式单一,以及文献探讨不足。     

Alkaline methanol–air system

Methanol is a promising fuel for power devices such as fuel cells because it has a high theoretical capacity per volume and weight, is relatively easy to handle and is easy to store. Many studies on the alkaline methanol fuel cell system were made in the 1960s and 1970s. The article gives a brief summary of these studies and shows some results of the new work started recently at the TU Graz, AustriaDedicated to Prof. Wolf Vielstich on the occasion of his 80th birthday in recogniton of his numerous contributions to interfacial electrochemistry.     

广州市售油漆铅含量检测结果与分析

为了解广州市场销售油漆铅含量,评估儿童油漆铅暴露的危险性,给有关部门实施油漆产品监管提供依据,对广州地区销售的油漆进行了抽查,样品经前处理后用火焰原子吸收光谱法检测其中的总铅和可溶性铅。结果表明,抽检的50个样本有30个可溶性铅超标,超标率为60%,最高铅含量22 700 mg/kg,高于限量252倍;36个样本总铅超标,超标率为72%,最高为153 000mg/kg,高于限量255倍;11个生产工厂有5间工厂生产的共24个产品可溶性铅和总铅全部超标,只有2间工厂共4个产品可溶性铅和总铅全部合格;由规模较小乡镇小厂和由大型的集团企业生产的油漆产品铅含量并没有明显差别;绿色、黄色和红色是铅含量较高的颜色;另抽查23个油漆调色色精、色粉和色浆,其中2个铅超标。可见广州市售油漆存在严重的铅污染,主要原因是生产过程中滥用含铅原料,职能部门应尽快落实相关标准法规,加强市场准入的监管,禁止高铅油漆的流通和使用,减少儿童日常生活中的铅暴露,防止铅中毒的发生。     

Qualitative and semi-quantitative analysis in ICP-AES using multivariate calibration

This paper describes a two step algorithm for qualitative and semiquantitative analysis in inductively coupled plasma—atomic emission spectroscopy (ICP-AES) including the preceding data acquisition. Sample and calibration spectra were recorded in 0.05 nm spectral windows centered about the most prominent lines of the 49 covered elements. In the first step of the analysis of an unknown sample spectrum it is decided which of these elements can be excluded from further operations because of the absence of their most prominent lines applying a multivariate criterion for peak detection. For the remaining elements quantitative analysis is performed via multivariate calibration taking into consideration the most prominent line of each element and possibly interfering lines of those elements which were not found absent during the first step. After the estimation of the element concentrations multivariate detection limits are used as criterion for the presence of an element. Results for six synthetic samples of increasing complexity prepared from standard solutions and three standard reference materials are given.     

Region coverage-aware path planning for unmanned aerial vehicles: A systematic review

The use of unmanned aerial vehicles (UAVs) to carry out remote aerial surveys has become prominent in recent years. The UAV-based survey faces several operational issues, such as complicated terrain, limited UAV resources, obstacles, sensor limitations, and other environmental factors. In addition, the coverage plan includes numerous objectives, such as lowering path length, maximizing coverage, and limiting survey time, necessitating multi-objective optimization. UAVs require effective coverage path planning (CPP) to generate the ideal route. It involves determining the path which encompasses every point inside the required region under different constraints. The process automates the process of route determination for autonomous operation by considering various environmental constraints. In this paper, we explore and analyze the existing research on the various techniques used in coverage route planning for UAVs. It provides an overview of the current state-of-the-art CPP methods for UAVs. The study discusses the key challenges and requirements of CPP for UAVs and presents various approaches proposed in the literature to tackle these challenges. We explore a variety of geometric flight patterns for the area of interest having UAV deployment. It also features multi-UAV and multi-region coverage strategies, providing a new dimension to UAV-based operations. The energy consumption of UAVs during CPP is an essential factor, as it influences their flight length and mission duration. The design of the CPP algorithm is determined by the unique requirements of the UAV application, such as the size and form of the region to be mapped, the existence of obstacles, and the desired coverage resolution. Path planning strategies in a three-dimensional environment and dynamic coverage are also included in the study. Moreover, we compare the existing strategies using different performance metrics to evaluate the success of covering missions. Finally, the problems and unresolved concerns related to UAV coverage path planning are examined to provide valuable insights to the readers.     

北秦岭地带断裂活动性氡气测试成果分析评价

采用断层气体测试方法, 对北秦岭地带主要断裂及其活动性进行了测试, 首次提出了该区断裂活动性测氡成果判别的相对标准。进而对区内典型的氡气测试成果剖面作了解释分析, 并判别了断裂 (带)的相对活动强弱与活动水平等有关断裂活动性问题。最后, 简要地探讨了在北秦岭地区未来可持续发展中断裂 (带)对其模式及格局的影响。