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61.
本文研究了非正则图的Q-矩阵的最大特征向量分量的最大比值,应用这个结论得到了非正则图的Laplacian特征值的一个上界,从而改进了Stevanovic的结论.  相似文献   
62.
刘普幸  杨泉 《资源科学》2012,34(3):566-571
利用敦煌绿洲气象站1955年-2010年日平均气温资料,采用气候倾向率、Mann-Kendall检验、相关分析及Morlet小波功率谱等方法分析了研究区胡杨生长季对全球气候变化的响应。结果表明:近56a来,研究区胡杨年生长季有开始日提前,终止日推后,年生长季天数延长的趋势;展叶始日有提前趋势,叶黄初日有推后趋势。胡杨生长季开始日、展叶始日分别与3月和4月平均气温呈负相关关系,胡杨生长季终止日、生长期天数及叶黄初日分别与10月、3月-11月及8月-9月平均气温呈正相关关系。胡杨生长季开始日、终止日、生长季天数、展叶期及叶黄初日均具有多个突变,存在3.77~8.33a的短尺度周期,这反映出研究区胡杨生长季对气候变化响应十分敏感。  相似文献   
63.
分析了DPSK调制格式的产生方式和频域特性,在分别考虑色散、PMD和非线性效应的情况下,通过求解非线性薛定谔方程,仿真了NRZ-DPSK,33%RZ-DPSK,50%RZ-DPSK和CSRZ-DPSK调制格式在40 Gbit/s单信道中的传输特性.仿真结果表明,在单独考虑色散和PMD的情况下,33%RZ-DPSK调制格式特性较好,在综合考虑色散、PMD和非线性效应情况下,CSRZ-DPSK调制格式特性更好.  相似文献   
64.
湿法消解样品后,文中利用ICP—AES法同时测定松花鸡蛋中钙、铁、锌、铜4种微量元素的含量.在优化实验条件下,RSD为0.30%-1.30%,加标回收率为95.45%-110.28%.方法简便、快速、准确、灵敏.  相似文献   
65.
Students with autism spectrum disorders (ASDs) are increasingly being educated within mainstream schools. While there is often an assumption that students with ASD who are academically capable will succeed in an inclusive educational placement, previous research has indicated that this is not always the case. Indeed, it seems that students with ASDs are often not equipped to cope with the social and communication demands of a mainstream classroom. Autism Spectrum Australia's (Aspect) satellite class programme aims to address this gap by blending specialised intervention with strategies to prepare students and receiving schools for transition to more inclusive educational placements. A long-term follow-up study comprising a parent survey of satellite class graduates and four detailed case studies was undertaken to determine whether these classes led to successful placement of students with ASD in more inclusive educational settings. Results indicated that a majority of graduates remained placed in more inclusive educational settings. Overall, parents were satisfied with the programme. Attendance at a satellite class was just one of a number of factors associated with positive outcomes in late adolescence. These findings are discussed in terms of their implications for teachers and school staff planning for and supporting students with ASDs in their transition to inclusive educational settings.  相似文献   
66.
Being victims of racial prejudice, religious intolerance, poverty, disempowerment and language loss it could be expected that indigenous people would be supportive of the Inclusion Movement with its philosophy of valuing and acceptance of all people. This supposition is examined for Māori, the indigenous people of Aotearoa/New Zealand. In particular, three research studies investigating Māori perspectives of intellectual disability, blindness and vision impairment, and autism spectrum disorder (ASD) are examined for evidence of inclusive and exclusive attitudes and practices. Findings show that while Māori participants’ opinions varied, people with intellectual disabilities, ASD, blindness and vision impairment were generally valued family members and many examples of inclusive attitudes and practices were shared. Core Māori values support Inclusion. It is proposed that incorporating these values into education and disability services will not only result in more culturally appropriate provisions for Māori but will also contribute to the greater inclusion of all disabled people whatever their ethnicity.  相似文献   
67.
谱序的发展由来已久,清代是谱序发展比较完善的时期,谱序的篇数庞大。随着时间的久远,新序和旧序的对比也比较明显。本文就新序和旧序内容上的不同,对其出现的原因和对应谱序的作用作了浅显的分析。  相似文献   
68.
认知无线电是一种可用于有效缓解当前频谱资源紧张的技术,而频谱感知是认知无线电的前提。针对低信噪比情况下频谱感知性能差的问题,提出一种将信号高阶统计量、协方差矩阵特征值与神经网络相结合的合作频谱感知算法。该算法考虑到认知用户与授权用户的信道衰落情况,利用神经网络较强的多分类能力,将最大-最小特征值之比、平均-最小特征值之比以及高阶统计量作为特征参数,通过神经网络实现合作频谱感知。仿真结果表明,该算法不仅在低信噪比情况下较其他算法具有更高的频谱检测率,而且对频谱中信号的调制类型也有较高的识别率。  相似文献   
69.
本文阐述扩频通信的工作原理及目前无线局域网的特点和主要传输方式,并就扩频通信的四种工作方式、扩频技术的特点和扩频技术在无线局域网中的应用前景等作了介绍  相似文献   
70.
Many teachers are sporadic in using evidence-based practice (EBP) concerning students with autism spectrum disorder (ASD). Numerous reasons have been posited for this. However, no single study has worked to understand the relative importance of identified criteria in the EBP decision-making processes of teachers. Through the development of a new survey tool, the Evidence-Based Practice Innovation Survey (EBPIAS), an exploration of the decision-making process of Australian teachers in their adoption and cessation of EBP was undertaken. Teachers rated the perception that an EBP would meet the needs of their students as the most important criteria in determining their use of EBP. Conversely, the judgement that an EBP did not meet the needs of their student was the most important criteria in their decision to cease use. In comparing the relevant importance of identified criteria, teachers rated the perception of training as the second-lowest consideration in their decision to adopt and cease using EBP. Consequently, there may need to be greater promotion of, or information concerning, the training required by teachers for effective implementation supporting a more balanced and holistic approach in assessing criteria impacting the adoption of EBP by teachers in the first instance, potentially lowering cessation rates.  相似文献   
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