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The Publication and Distribution of Chinese Standards and Other Standards-related Products
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作者 Bai Demei 《China Standardization》 2005年第6期47-48,共2页
Standards Press of China (SPC), founded in October 1963, is the only publication center in China licensed to publish national standards, trade standards, and books concerned with standardization, quality, and other sc... Standards Press of China (SPC), founded in October 1963, is the only publication center in China licensed to publish national standards, trade standards, and books concerned with standardization, quality, and other science and technology. The main publications are as following: 展开更多
关键词 SPC The Publication and distribution of Chinese standards and Other standards-related Products
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Statistical Characteristics of Raindrop Size Distribution in the Tibetan Plateau and Southern China 被引量:22
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作者 Yahao WU Liping LIU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第6期727-736,共10页
The characteristics of raindrop size distribution (DSD) over the Tibetan Plateau and southern China are studied in this paper, using the DSD data from April to August 2014 collected by HSC-PS32 disdrometers in Nagqu... The characteristics of raindrop size distribution (DSD) over the Tibetan Plateau and southern China are studied in this paper, using the DSD data from April to August 2014 collected by HSC-PS32 disdrometers in Nagqu and Yangjiang, com- prising a total of 9430 and 63661-rain raindrop spectra, respectively. The raindrop spectra, characteristics of parameter variations with rainfall rate, and the relationships between reflectivity factor (Z) and rainfall rate (R) are analyzed, as well as their DSD changes with precipitation type and rainfall rate. The results show that the average raindrop spectra appear to be one-peak curves, the number concentration for larger drops increase significantly with rainfall rate, and its value over southern China is much higher, especially in convective rain larger drops, especially for convective rain in southern China. Standardized Gamma distributions better describe DSD for All three Gamma parameters for stratiform precipitation over the Tibetan Plateau are much higher, while its shape parameter (,u) and mass-weighted mean diameter (Dm), for convective precipitation, are less. In terms of parameter variation with rainfall rate, the normalized intercept parameter (Nw) over the Tibetan Plateau for stratiform rain increases with rainfall rate, which is opposite to the situation in convective rain. The/1 over the Tibetan Plateau for stratiform and convective precipitation types decreases with an increase in rainfall rate, which is opposite to the case for Dm variation. In Z-R relationships, like "Z = ARb'', the coefficient A over the Tibetan Plateau is smaller, while its b is higher, when the rain type transfers from stratiform to convective ones. Furthermore, with an increase in rainfall rate, parameters A and b over southern China increase gradually, while A over the Tibetan Plateau decreases sub- stantially, which differs from the findings of previous studies. In terms of geographic location and climate over the Tibetan Plateau and southern China, the precipitation in the pre-flood seasons is dominated by strong convective rain, while weak convective rain occurs frequently in northern Tibet with lower humidity and higher altitude. 展开更多
关键词 Tibetan Plateau raindrop size distribution precipitation classification standardized gamma distribution
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The Mandatory Energy Efficiency Standard for Distribution Transformer soon Publicized in China
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作者 By Zhao Yuejin 《China Standardization》 2005年第3期16-19,共4页
Owning to the rapid economy development in China and sharp increase of energy consumption in recent years, energy shortage is increasingly apparent and becoming an important obstacle to the sustainable development of ... Owning to the rapid economy development in China and sharp increase of energy consumption in recent years, energy shortage is increasingly apparent and becoming an important obstacle to the sustainable development of our economy. With the aim to relieve the problem of energy shortage, the State Development and Reform Commission places the great emphasis of energy-saving work on improving energy efficiency of industrial energy-consuming products in energy-saving work. The General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China(AQSIQ) has issued and implemented two energy efficiency standards for three-phase induction motors and displacement air compressor, and will soon issue another two energy efficiency standards for clean- water centrifugal pumps and ventilation fans. The transformer is a kind of electric equipment widely used in many industries in national economy, with features of great amount of use, long period of operation and tremendous potential of energy-saving. So, it is necessary to develop the standard of energy efficiency for distribution transformers.It has been an issue of common concern for all countries in the world to reduce the consumption of transformers and upgrade their distribution efficiency. 展开更多
关键词 The Mandatory Energy Efficiency Standard for distribution Transformer soon Publicized in China
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Abnormal Behavior Detection and Recognition Method Based on Improved ResNet Model 被引量:4
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作者 Huifang Qian Mengmeng Zheng Xuan Zhou 《Computers, Materials & Continua》 SCIE EI 2020年第12期2153-2167,共15页
The core technology in an intelligent video surveillance system is that detecting and recognizing abnormal behaviors timely and accurately.The key breakthrough point in recognizing abnormal behaviors is how to obtain ... The core technology in an intelligent video surveillance system is that detecting and recognizing abnormal behaviors timely and accurately.The key breakthrough point in recognizing abnormal behaviors is how to obtain the effective features of the picture,so as to solve the problem of recognizing them.In response to this difficulty,this paper introduces an adjustable jump link coefficients model based on the residual network.The effective coefficients for each layer of the network can be set after using this model to further improving the recognition accuracy of abnormal behavior.A convolution kernel of 1×1 size is added to reduce the number of parameters for the purpose of improving the speed of the model in this paper.In order to reduce the noise of the data edge,and at the same time,improve the accuracy of the data and speed up the training,a BN(Batch Normalization)layer is added before the activation function in this network.This paper trains this network model on the public ImageNet dataset,and then uses the transfer learning method to recognize these abnormal behaviors of human in the UTI behavior dataset processed by the YOLO_v3 target detection network.Under the same experimental conditions,compared with the original ResNet-50 model,the improved model in this paper has a 2.8%higher accuracy in recognition of abnormal behaviors on the public UTI dataset. 展开更多
关键词 ResNet abnormal behavior recognition YOLO_v3 adjustable jump link coefficients model standard normal distribution
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Rubidium-beam microwave clock pumped by distributed feedback diode lasers
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作者 刘畅 周晟 +1 位作者 王延辉 侯士敏 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第11期151-154,共4页
A rubidium-beam microwave clock, optically pumped by a distributed feedback diode laser, is experimentally investigated. The clock is composed of a physical package, optical systems, and electric servo loops. The phys... A rubidium-beam microwave clock, optically pumped by a distributed feedback diode laser, is experimentally investigated. The clock is composed of a physical package, optical systems, and electric servo loops. The physical package realizes the microwave interrogation of a rubidium-atomic beam. The optical systems, equipped with two 780-nm distributed feedback laser diodes, yield light for pumping and detecting. The servo loops control the frequency of a local oscillator with respect to the microwave spectrum. With the experimental systems, the microwave spectrum, which has an amplitude of 4 n A and a line width of 700 Hz, is obtained. Preliminary tests show that the clock short-term frequency stability is 7 × 10^-11 at 1 s, and 3 × 10^-12 at 1000 s. These experimental results demonstrate the feasibility of the scheme for a manufactured clock. 展开更多
关键词 quantum frequency standard atomic clock atomic beam distributed feedback
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