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1.
马骥 《科技风》2012,(15):63
瓦斯检测在煤矿、石油、冶金等行业的安全生产中有着极其重要的意义。本文在分析了传统瓦斯检测方法存在问题的基础上,设计了一种新的瓦斯检测方法:即基于本征光谱吸收的瓦斯检测方法。设计中采用了封闭式双光路结构的光探头,硬件电路给出了光电转换、带通滤波等电路的设计方案;并且硬件实施运用单片机及键盘输入和通讯装置来达到设计的完整性。  相似文献   

2.
针对图像阈值分割问题,基于Renyi熵与模糊集理论,构造出一种模糊Renyi熵用于图像直方图阈值化分割。在建立的模糊Renyi熵基础上,依据最大熵原则获取用于阈值分割的最佳阈值。通过在大量真实图像上的实验,验证了提出方法的有效性。  相似文献   

3.
本文是系统研究"基于钻芯检测法定量评估基桩质量的研究"系列论文的第五篇。这组系列研究论文对"钻芯检测法"推广过程中常见的问题——"定性评估的缺陷、定量评估的可行性及实际操作"作了较深入的探讨,增强了检测结果的客观性,降低了检测难度,为钻芯法检测基桩质量的科学研究和工程应用提供了一条新的解决途径。本文主要解决了基桩松散段长度与完整性等级定量评估之间一一对应的问题,迈出了基桩检测技术规范再次修订的关键一步。  相似文献   

4.
以应力波反射法基桩检测的基本原理,论述了基桩从现场测试到室内曲线分析中注意的事项、易出现的问题.  相似文献   

5.
本文是系统研究"基于钻芯检测法定量评估基桩质量的研究"系列论文的第二篇。这组系列研究论文对"钻芯检测法"推广过程中常见的问题——"定性评估的缺陷、定量评估的可行性"作了较深入的探讨。增强了检测结果的客观性,为钻芯法检测基桩质量的科学研究和工程应用提供了一条新的解决途径。本文主要解决了基桩完整性评价时建模难的问题及专家权重的合理确定,是基桩钻芯检测定量评估的研究出发点。  相似文献   

6.
本文是系统研究"基于钻芯检测法定量评估基桩质量的研究"系列论文的第六篇。这组系列研究论文对"钻芯检测法"推广过程中常见的问题——"定性评估的缺陷、定量评估的可行性及实际操作"作了较深入的探讨,增强了检测结果的客观性,降低了检测难度,为钻芯法检测基桩质量的科学研究和工程应用提供了一条新的解决途径。本文主要解决了持力层核心指标与基桩完整性等级定量评估之间一一对应的问题,开拓了持力层在基桩质量评估中的核心基础作用。  相似文献   

7.
《科技风》2017,(19)
低应变法是基桩完整性检测的重要手段之一,因造价低,时间短,可以说是目前绝大多数工程首选方法。但低应变检测基桩完整性,也有其局限性。其方法对桩身缺陷无法做定量判定,无法判定基桩的具体缺陷。所以当低应变法检测基桩发现异常时,需要通过其他手段,如开挖、钻芯等方法进行验证。本文通过现场测试时实际发生问题,简单分析应如何处理。  相似文献   

8.
基于振动的基桩损伤检测方法是通过结构的反应或动力特性的变化来对结构的整体性能进行损伤检测的。基于振动的结构损伤检测是一个明显的反问题,其核心思想是模态参数是结构物理特性的函数,只要结构系统的物理特性发生改变,必然会导致模态特性的改变。将结构系统的实测模态特性与健康结构的模态特性进行比较,来判断结构是否发生损伤。  相似文献   

9.
本文是系统研究"基于钻芯检测法定量评估基桩质量的研究"系列论文的第三篇。这组系列研究论文对"钻芯检测法"推广过程中常见的问题——"定性评估的缺陷、定量评估的可行性及实际操作"作了较深入的探讨,增强了检测结果的客观性,降低了检测难度,为钻芯法检测基桩质量的科学研究和工程应用提供了一条新的解决途径。本文主要解决了钻芯孔数与完整性等级定量评估之间难以建模的问题,并提出了钻孔特征值计算实用公式,迈出了基桩钻芯检测定量评估的关键一步。  相似文献   

10.
船舶柴油机的油液铁谱分析是实现故障诊断的重要方法。基于油液铁谱分析的船舶柴油机故障的传统检测方法是采用超声波固-液界面检测算法,导致柴油机故障信号出现环绕波齐次衰减,故障诊断效果不好。提出一种基于模糊伸缩约束控制柴油机油液铁谱分析的故障诊断方法,基于DSP设计船舶柴油机油液铁谱制谱仪和铁谱故障检测硬件系统,采用ADSP-BF537设计油液铁谱分析的电源,选用ADM706SAR芯片设计电路复位。算法设计中,构建油液铁谱分析能量模糊规则方程,设定模糊伸缩约束控制条件补偿油液铁谱分析模型的不确定性,实现对故障的准确定位和检测。实验结果表明,采用该方法进行柴油机故障信号油液铁谱分析和故障诊断,故障亮点定位准确,具有多故障状态监测应答的性能,故障准确发现概率提高显著。  相似文献   

11.
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.  相似文献   

12.
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.  相似文献   

13.
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.  相似文献   

14.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.  相似文献   

15.
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.  相似文献   

16.
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.  相似文献   

17.
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.  相似文献   

18.
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence  相似文献   

19.
<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese  相似文献   

20.
<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.  相似文献   

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