正交变换在积分中的应用     

游家桦 《贵阳金筑大学学报》2003,(3)

利用正交变换,在重积分、曲面积分中处理积分的变数替换。  相似文献   

信息资源管理研究的多重视角及其共同体的形成（Ⅲ）——学科互涉特征与IRM共同体的形成   总被引：2，自引：0，他引：2  

宋恩梅 《中国图书馆学报》2008,34(1)

信息资源管理领域中,以政府、企业和情报学界的不同视角的研究各具特点。随着发展,其研究将会由关注技术转向关注内容,并进而形成一种综合型研究视角和整合机制。自然科学领域中"科学共同体"概念适用于人文社科领域,也适用于IRM。IRM共同体有其共同规范。  相似文献   

Seeking Nettle Textiles – Utilizing a Combination of Microscopic Methods for Fibre Identification     

Jenni A. Suomela  Krista Vajanto  Riikka Räisänen 《文物保护研究》2018,63(7):412-422

Bast fibres have been commonly used as a textile material in Northern Europe since Neolithic times. However, the process of identifying the different species has been problematic, and many important questions related to their cultural history are still unanswered. For example, a modified Herzog test and the presence of calcium oxalate crystals have both been used in identification. In order to generate more reliable results, further research and advancement in multi-methodological methods is required. This paper introduces a combination of methods which can be used to identify and distinguish flax (Linum usitatissimum), hemp (Cannabis sativa), and stinging nettle (Urtica dioica). The research material consisted of reference fibres and 25 fibre samples obtained from 12 textiles assumed to be made of nettle. The textiles were from the Finno-Ugric and Historical Collections of The National Museum of Finland. The fibre samples were studied by observing the surface characteristics and cross sections with transmitted light microscopy, and by using a modified Herzog test with polarized light, in order to identify the distinguishable features in their morphological structures. The study showed that five out of 25 samples were cotton, 16 nettle, one flax, and one hemp. Findings from two samples were inconsistent. The results show that it is possible to distinguish common north European bast fibres from each other by using a combination of microscopic methods. Furthermore, by utilizing these combined methods, new and more reliable information could be obtained from historical ethnographic textiles, which creates new vistas for the interpretation of their cultural history.  相似文献   

Wearable skin-like optoelectronic systems with suppression of motion artifacts for cuff-less continuous blood pressure monitor     

Haicheng Li  Yinji Ma  Ziwei Liang  Zhouheng Wang  Yu Cao  Yuan Xu  Hua Zhou  Bingwei Lu  Ying Chen  Zhiyuan Han  Shisheng Cai  Xue Feng 《国家科学评论(英文版)》2020,7(5):849

According to the statistics of the World Health Organization, an estimated 17.9 million people die from cardiovascular diseases each year, representing 31% of all global deaths. Continuous non-invasive arterial pressure (CNAP) is essential for the management of cardiovascular diseases. However, it is difficult to achieve long-term CNAP monitoring with the daily use of current devices due to irritation of the skin as well as the lack of motion artifacts suppression. Here, we report a high-performance skin-like optoelectronic system integrated with ultra-thin flexible circuits to monitor CNAP. We introduce a theoretical model via the virtual work principle for predicting the precise blood pressure and suppressing motion artifacts, and propose optical difference in the frequency domain for stable optical measurements in terms of skin-like devices. We compare the results with the blood pressure acquired by invasive (intra-arterial) blood pressure monitoring for >1500 min in total on 44 subjects in an intensive care unit. The maximum absolute errors of diastolic and systolic blood pressure were ±7/±10 mm Hg, respectively, in immobilized, and ±10/±14 mm Hg, respectively, in walking scenarios. These strategies provide advanced blood pressure monitoring techniques, which would directly address an unmet clinical need or daily use for a highly vulnerable population.  相似文献   

常温微波催化合成二糠叉环己酮     

陈良壁 《南平师专学报》2006,25(2):30-33

本文研究了在室温下微波催化合成二糠叉环己酮的优化工艺条件。结果表明:糠醛与环己酮摩尔比2:1,功率为320W,反应2分钟时,二糠叉环己酮的产率最大,可达90.2%。  相似文献   

大气汽溶胶复合微粒子群的光学截面及红外发射率光谱的计算     

田贵才  陈国宝  王红岩 《通化师范学院学报》2003,24(2):17-21

在章[1]的基础上，根据M.L.AdenH和M.Merker的复合微粒子光散射理计算了汽溶胶大气中复合微粒子模型的光学特性，得到了汽溶胶的散射截面、吸收截面和消光截面以及红外发射率光谱，为研究大气红外传输提供了计算方法。  相似文献   

基于MATLAB的Reed-Solomon编解码仿真     

刘兰  林军 《广东技术师范学院学报》2006,27(6):18-20

RS纠错码被广泛用在各种数字通信、数字广播和数据存储系统中.本文解释了纠错理论及RS码的相关原理,通过MATLAB仿真分析RS编码的误码率与信噪比之间的关系.  相似文献   

正交表L16(43)的不同结构     

庞善起  刘斐 《商丘职业技术学院学报》2004,3(3):4-5

按照文[2]的定义和方法，区分了正交表L16(4^3)的所有不同的结构，并用极大最小距离给出了不同结构的差别，并且找到了同一结构中正交表的关系．  相似文献   

广义正交矩阵的几个性质     

唐亮 《株洲师范高等专科学校学报》2002,7(5):34-36

推广了正交矩阵 ,并研究了广义正交矩阵在行列式、特征根、伴随矩阵等问题中的四个性质  相似文献   

全光纤无源耦合器件制作过程中的实践创新能力培养   总被引：1，自引：0，他引：1  

王丽  陈江博  金绍兴  何士雅 《实验技术与管理》2006,23(5):13-15

结合本科生毕业设计“全光纤光功率比耦合器件的制备”的实践过程,在理论上基于光波的耦合波方程,对熔融拉锥单模光纤耦合器的功率耦合比与拉伸长度、拉伸位置和损耗的关系进行数值模拟,使本科生在毕业设计的有限时间内掌握一种基本软件工具。通过设计过程中的实践活动,学生在指导教师的科研理念引导下,利用实验室现有的设备制作出2×2型、单窗口1×2型1550 nm和1310 nm宽带耦合器, 并完成了对制备出的光纤耦合器的光功率和光谱的检测。在实践教学过程中,突出体现了知识、能力、科研素质提高和创新能力的培养。通过无源耦合器件的制备,培养了学生的实践动手能力和科研思维能力, 为今后的学习或就业奠定了良好的基础。  相似文献