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101.
张海芳 《思茅师范高等专科学校学报》2015,(3):47-49
对于三维欧氏空间中二次曲面的不变量,已经有过大量的详细的研究讨论,但对于高维空间中的二次曲面不变量却很少有人进行探究。为此,就针对四维欧氏空间中二次曲面的不变量进行了简单的研究。 相似文献
102.
何洪霞 《鞍山师范学院学报》2015,(3):37-39
本文侧重于对该构式的语义进行共时性描写,探讨该构式在现代汉语中的结构特点及语义范畴,采用对相关句型互相转换并对其进行对比分析的方法,揭示“为N所V”构式中“V”的语义特征,并对该构式语义焦点进行分析,找出其结构所在句子的自然焦点、对比焦点和否定焦点的位置规律。 相似文献
103.
Daniel Tan Lei Shek Florence Ka Yu Wu Wen Yu Chai 《Assessment & Evaluation in Higher Education》2015,40(8):1017-1031
Under the new four-year undergraduate programme, a general education framework titled ‘General University Requirements’ (GUR) has been developed and implemented since 2012/2013 at Hong Kong Polytechnic University (PolyU). To evaluate the implementation and effectiveness of the GUR in its first year, focus group interviews with students were carried out. In 13 focus groups, 62 first-year students from eight faculties/schools who took GUR subjects in 2012/2013 academic year were interviewed by trained researchers. Results showed that students generally had good perceptions of the GUR in terms of the subject content, teaching methods and the overall effectiveness of the subjects. The interactive teaching and learning initiatives adopted in GUR subjects were particularly appreciated, although students expressed minor concerns on the administration of GUR subjects. The results suggest that the first-year implementation of the GUR at PolyU was generally smooth and successful from the perspectives of the students. 相似文献
104.
李双剑 《渭南师范学院学报》2015,(1):63-67
近代汉语中的否定词位于"被"字之后是一种特殊否定式"被"字句,即NP1+被(+NP2)+Neg+VP格式的句子,这种句式的产生与"被"字的虚化程度和焦点表达有关。这种句式的消亡可以归结为语言的经济性原则要求,以及"被"字的现实标记性与否定词的非现实标记性的冲突。 相似文献
105.
Shereen C. Naser Katherine Clonan-Roy Kimberly A. Fuller Elizabeth A. Goncy Nicole Wolf 《Psychology in the schools》2022,59(1):34-50
The purpose of this study is to describe the experiences of lesbian, gay, bisexual, transgender, questioning, intersex, two spirit, and queer (LGBTQ+) youth with school-based sexuality education (SBSE), as well as to document strategies LGBTQ+ youth are using to address their evolving and specific sexual health needs outside of SBSE. Researchers conducted focus groups with 17 adolescents (ages 14–18) from urban and suburban Midwestern cities. Results of this study indicate LGBTQ+ youth find SBSE to be heteronormative, cisgender focused, and primarily focused on pregnancy and disease prevention, which contributes to LGBTQ+ youth experiences of exclusion. In response to SBSE that did not meet student needs, participants reported seeking sexual health information outside of SBSE. Other sources included family and other trusted adults, the Internet, and community resource centers. Students reported variable rates of use and trustworthiness across these resources. Results of this study suggest that school personnel should consider alternatives to traditional SBSE models to meet the needs of LGBTQ+ youth, and that an important part of SBSE should include guidelines for Internet safety. 相似文献
106.
It is well known that sliding mode control is based on the definition of an invariant manifold, where the system dynamics are forced to in a finite time. Such a manifold is somewhat arbitrarily defined, as long as the system dynamics are stable on it. Computational and control effort may vary depending on selected manifold. Obviously, if a system has naturally acceptable stable dynamics around a desired equilibrium point, no control is needed unless uncertainties or disturbances are present. It would be desirable that if such a system had uncertainties or disturbances, the control effort be designed only to overcome the effect of such factors. For a system with first order dynamics and affine control input, designing a sliding mode control overcoming only such uncertainties or disturbances is a trivial task. When a higher order dynamics system is involved, unit control may be used, where the input control signals are not discontinuous, but when only discontinuous control inputs are available, a design approach is not readily available. In this paper, taking advantage of the natural stable dynamics of a system, a sliding mode control approach is introduced for designing multiple discontinuous control inputs, where the control effort overcomes only uncertainties, disturbances or unstable dynamics. Two illustrative examples are given in order to show the feasibility of the method. 相似文献
107.
文章以中国期刊全文数据库(CNKI)为数据源,以发表在CSSCI和核心期刊的2004-2013年有关开放存取的507篇文献为研究对象,对其进行年代分析,研究发现:2004-2008年开放存取研究呈现迅猛增长趋势,2009-2013年开放存取的研究趋势平稳,因此文章将开放存取的发展分为2个阶段,即开放存取研究的第一个阶段(2004-2008年)、开放存取研究的第二个阶段(2009-2013年)。利用关键词共现分析方法分析我国开放存取在每个阶段的研究热点,并采用社会网络分析方法分析开放存取文献的高产作者,以透析国内开放存取领域的研究热点和作者合作团体,从多方面揭示国内开放存取的发展现状和研究趋势。 相似文献
108.
文章研究旨在优化前期筛选到的米曲霉HML366产β-葡萄糖苷酶的培养基条件。通过单因素实验和响应面设计对米曲霉HML366产β-葡萄糖苷酶的培养基条件进行了优化组合,确定最佳的发酵培养基配方为:甘蔗渣3.49%,豆饼粉0.375%,KH2PO4 0.255%。在此培养条件下得到β-葡萄糖苷酶酶活力达92.64 U/g,是未优化前酶活71.12 U/g的1.30倍。 相似文献
109.
110.
根据古宋河沿河地带所设两个监测断面地下水污染浓度实测资料,采取渐进错位相关分析法,分析古宋河地表水与地下水污染相关关系,可知河水与该处地下水中污染物传播时间较长;依据水位观测资料,分析知河道水位以大于1m水位差高与地下水位;通过现场渗透试验资料确定地下水渗透参数,采用裘布衣公式计算河道地表水与地下水补排关系,得出右岸河水平均每天补给地下水3m^3,该河地表水污染对地下水的影响很小;利用了MATLAB软件编程进行数据分析和处理,建立回归方程;选取氯化物作为相关分析示例,结果显示地下水的氯化物值与测井距离相关性最大,与时间和地表水的监测值相关性很小,地表水与地下水之间的线性相关关系不明显。 相似文献