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基于复制测量法的球头立铣刀磨损预测研究 被引量:1
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作者 孙博 陈锦江 +2 位作者 王芳 孙占伟 田广伟 《组合机床与自动化加工技术》 北大核心 2016年第10期116-119,共4页
论文提出一种测量球头立铣刀磨损量的复制测量方法并分析该方法的误差。以铣刀径向磨损量为研究对象进行刀具磨损试验,找出铣削参数对刀具磨损的影响规律,得出径向磨损量增量与铣削参数的铣刀磨损模型和刀具寿命经验公式,并通过试验验... 论文提出一种测量球头立铣刀磨损量的复制测量方法并分析该方法的误差。以铣刀径向磨损量为研究对象进行刀具磨损试验,找出铣削参数对刀具磨损的影响规律,得出径向磨损量增量与铣削参数的铣刀磨损模型和刀具寿命经验公式,并通过试验验证磨损模型具有较高精度,可用于磨损量预测。 展开更多
关键词 球头立铣刀 径向磨损量 复制测量 磨损试验
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Electrical bioimpedance gastric motility measurement based on an electrical-mechanical composite mechanism 被引量:2
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作者 Shu Zhao Hong Sha +1 位作者 Zhang-Yong Li, Chao-Shi Ren 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第25期3282-3287,共6页
AIM: To introduce a bioimpedance gastric motility mea- surement method based on an electrical-mechanical composite concept and a preliminary clinical application. METHODS: A noninvasive gastric motility measure- men... AIM: To introduce a bioimpedance gastric motility mea- surement method based on an electrical-mechanical composite concept and a preliminary clinical application. METHODS: A noninvasive gastric motility measure- ment method combining electrogastrograrn (EGG) and impedance gastric motility (IGM) test was used. Prelim- inary clinical application studies of patients with func- tional dyspepsia (FD) and gastritis, as well as healthy controls, were carried out. Twenty-eight FD patients (mean age 40.9±9.7 years) and 40 healthy volun- teers (mean age 30.9±7.9 years) were involved. IGM spectrum was measured for both the healthy subjects and FD patients, and outcomes were compared in the FD patients before treatment and 1 wk and 3 wk after treatment. IGM parameters were obtained from 30 erosive gastritis patients (mean age 50.5±13.0 years) and 40 healthy adults, and IGM and EGG results were compared in the gastritis patients before treatment and 1 wk after treatment.RESULTS: There were significant differences in the IGM parameters between the FD patients and healthy subjects, and FD patients had a poorer gastric motility [percentage of normal frequency (PNF) 70.8±25.5 in healthy subjects and 28.3 =t= 16.9 in FD patients, P 〈 0.01]. After 1 wk administration of domperidone 10 mg, tid, the gastric motility of FD patients was not im- proved, although the EGG of the patients had returned to normal. After 3 wk of treatment, the IGM rhythm of the FD patients became normal. There was a significant difference in IGM parameters between the two groups (PNF 70.4:1:25.5 for healthy subjects and 36.1 4- 21.8 for gastritis patients, P 〈 0.05). The EGG rhythm of the gastritis patients returned to normal (frequency insta- bility coefficient 2.22±0.43 before treatment and 1.77 :t: 0.19 one wk after treatment, P 〈 0.05) after 1 wk of treatment with sodium rabeprazole tablets, 10 mg, qd, po, qm, while some IGM parameters showed a tenden- cy toward improvement but had not reached statistical significance. CONCLUSION: The electrical-mechanical composite measurement method showed an attractive clinical appli- cation prospect in gastric motility research and evaluation. 展开更多
关键词 Gastric motility Electrical bioimpedance Electrical-mechanical composite ELECTROGASTROGRAM
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Rehabilitation Soils with Date Palm Mulching Treatments
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作者 Modi Ahmed A. M. Al-Dousari 《Journal of Agricultural Science and Technology(A)》 2018年第3期129-141,共13页
Kuwait is located in hyper arid desert environment. This geographical location and irrational human activities accelerate the expansion of land degradation problem. In order to rehabilitate the degraded areas it is ne... Kuwait is located in hyper arid desert environment. This geographical location and irrational human activities accelerate the expansion of land degradation problem. In order to rehabilitate the degraded areas it is necessary to use soil and water resources in sustainable manner. Owing to these reasons it is essential to use appropriate methods based on the scientific diagnostics of the problem. It is compulsory to identify, specify and test different efficient, cost-effective and environment friendly sound sustainable sand control measures such as, semi-circular bunds, square micro catchment and checker board palm leaves to rehabilitate degraded lands in Liyah refilled quarries. To evaluate the impact of rehabilitation method through mulching with date palm leaves soil samples were collected (control and rehabilitation sites with square micro catchment) prior to the implementation plan and post completion of the project (three years). In this study will be highlighted on detail the results of using square micro catchment and with short brief descriptions on other water harvesting techniques. The results showed an improvement of physical soil properties after the application of these techniques. Soil fertility increased through increasing the quantity of fine and very fine sand. The soil moisture at the surface soil increased from 0.085% to 1.62% after the treatment. The untreated soil has high bulk density about 2 g/cm3 and low porosity about 27%. However, after the soil was ploughed and mulched the bulk density decreased to 0.03 g/cm3. And porosity improved 98%. This study conserved the irrigation water through reducing the proportion of soil evaporation, in addition to the creation of optimum condition for plant growth. The aim of this study was to analyze the effect of using organic mulch date palm leaves with water harvesting techniques on the physical and biological properties of degraded soil in Liyah area. 展开更多
关键词 Control measures degraded lands REHABILITATION MULCHING
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Titration Method Validation of Live Vaccines against Infectious Bursal Disease
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作者 Fatima Tahiri Khadija Id Sidi Yahia +1 位作者 Benaissa Attrassi Driss Belghyti 《Journal of Life Sciences》 2013年第10期1084-1102,共19页
Validating a method of analysis goes through different steps, which aims at testing the normality of measurements distribution, estimating the uncertainty of the components of a measurement (i.e., accuracy and correc... Validating a method of analysis goes through different steps, which aims at testing the normality of measurements distribution, estimating the uncertainty of the components of a measurement (i.e., accuracy and correctness), and finally, define the control tests of non degradation of the method performances. This paper outlines the steps for validating a biological method of analysis. It involves the construction of an experimental design, a statistical model, and the preparation of an interne laboratory reference material (pilot vaccine). The latter is used to study the impact of deviation and variation factors, in order to, optimize the analytical method, to evaluate the bias (random error), and to calculate the uncertainty of measurement, and make the control charts. This method is applied in the titration of live viral vaccines of Gumboro disease on chicken's embryos fibroblasts. The experimental results show that potential influence factors related to the titration method had no significant influence on the obtained results. Taking into account these results, an operating mode has been elaborated. The finalized method proved to be faithful to standard deviation of repeatability and reproducibility of 0.21 and 0.22, respectively, with a confidence level of 95%. The calculated uncertainty of measurement is equal to 0.2, which represents the average error level of a titer. A homogeneous stock of interne laboratory reference vaccine (MRIL), with an average titer of 5.9 log DIT 50, was produced and the control chart set in away to provide the laboratory with an important tool of control and monitoring of the viral titers evolution in time, as well as, the mastery of the validated titration method performances. 展开更多
关键词 Live vaccine of infectious bursal disease titration method characterization experimental design method validation ACCURACY UNCERTAINTY STATISTICS control chart.
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多天线频谱共享CR-NOMA系统安全中断性能分析
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作者 吕铄 嵇建波 《电子测量技术》 北大核心 2023年第17期71-78,共8页
认知无线电(CR)非正交多址接入(NOMA)网络(记为CR-NOMA)已是无线通信领域的研究热点之一。由于无线信道的开放性,使得无线网络的安全通信成为当前急需解决的问题。该文研究了频谱共享多天线CR-NOMA网络安全中断性能,首先分析了最优天线... 认知无线电(CR)非正交多址接入(NOMA)网络(记为CR-NOMA)已是无线通信领域的研究热点之一。由于无线信道的开放性,使得无线网络的安全通信成为当前急需解决的问题。该文研究了频谱共享多天线CR-NOMA网络安全中断性能,首先分析了最优天线选择(OAS)方案的安全中断概率(SOP),并推导了其精确的闭合表达式。其次,分析了空时传输(STT)方案的SOP,并推导了其精确的闭合表达式。最后,对次用户两种方案的SOP渐近性能进行了分析,揭示了系统参数对SOP的影响。最后,采用Monte Carlo仿真验证了理论分析的正确性。研究发现,两种方案基站分别存在一个最优峰值发射功率,使得远距离次用户的安全中断性能最佳。仿真结果表明增大基站峰值发射功率,OAS方案的近距离次用户的SOP会始终优于STT方案,远距离次用户的SOP会劣于STT方案。 展开更多
关键词 认知无线电 非正交多址接入 安全中断性能 安全中断概率
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