中职学生对51单片机双重循环语句的理解

在51单片机学习中有许多的语句,其中,循环语句在实际应用中突显出极为重要的作用。现在学习51单片机的人、爱好者越来越多,对于初学者在没有C语言的基础下,掌握双重循环可能有些困难,在教学总结中发现通过对编程语言进行完整书写、表达会有效地解决此问题。     

智能数字式工频相位差计

介绍了一种用单片机测量两列频率相同的相位差技术 ,并分析了电路的组成和工作原理。     

The Eurasian Steppe is an important goat propagation route: A phylogeographic analysis using mitochondrial DNA and Y‐chromosome sequences of Kazakhstani goats

Goats (Capra hircus) were domesticated in the Fertile Crescent and propagated all over the world. The Silk Road through the Eurasian Steppe belt is a possible propagation route for domestic goats to Central Asia. Kazakhstan is in close geographical proximity to domestication centers and covers the majority of the Eurasian Steppe belt. In this study, we examined the genetic diversity and phylogeographic structure of Kazakhstani goats. The mtDNA sequences of 141 Kazakhstani goats were categorized into haplogroups A, C, and D, of which haplogroup A was predominant (97%), whereas haplogroups C and D were detected at low frequencies (1.4% each). The Kazakhstani haplotypes C were thzen categorized into Asian mtDNA type. Sequence analysis of the SRY gene on the Y‐chromosome in 67 male Kazakhstani goats revealed two haplotypes: Y1A (64%) and Y2A (36%). Analysis of the distribution of mtDNA haplogroups and SRY haplotypes from Eurasia and Africa demonstrated genetic similarity among animals from Kazakhstan, Mongolia, and Northwest China located on the Eurasian Steppe belt. These phylogeographic results suggested that the Eurasian Steppe belt was an important propagation route for goats to Central Asia.     

Genetic structure of the oriental white stork (Ciconia boyciana): implications for a breeding colony in a non‐breeding area

The oriental white stork (Ciconia boyciana) is a threatened species, and their numbers are still in decline due to habitat loss and poaching. China is a breeding and main wintering area for this animal and in recent years some individuals have been found breeding in wintering areas and at some stopover sites. These new breeding colonies are an exciting sign, however, little is understood of the genetic structure of this species. Based on the analysis of a 463‐bp mitochondrial DNA (mtDNA) control region, we investigated the genetic structure and genetic diversity of 66 wild oriental white storks from a Chinese population. We analyzed the sequences of 66 storks obtained in this study and the data of 17 storks from a Japanese population. Thirty‐seven different haplotypes were detected among the 83 samples. An analysis of molecular variance showed a significant population subdivision between the two populations (F_ST= 0.316, P < 0.05). However, the phylogenetic analysis revealed that the samples from the different populations did not form separate clusters and that there were genetic exchanges between the two populations. Compared with the Japanese population, the Chinese population had a relatively higher genetic diversity with a haplotype diversity (hπ SD) of 0.953 ± 0.013 and a nucleotide diversity (π± SD) of 0.013 ± 0.007. The high haplotype diversity and low nucleotide diversity indicate that this population might be in a rapidly increasing period from a small effective population. A neighbor‐joining tree analysis indicated that genetic exchange had occurred between the newly arisen southern breeding colony and the northern breeding colony wintering in the middle and lower Yangtze River floodplain. These results have important implications for the conservation of the oriental white stork population in China.     

陆空两用车同步切换装置设计分析

以一种典型的陆空两用车为研究对象,根据两用车飞行与行驶不同工况需要切换与同步的要求,设计一款能够满足传递与切断动力的同步装置。经过方案三维建模、相关零部件的工程化设计、建立实验平台等一系列过程,完成了陆空两用车工况切换同步装置的设计。     

槽模圈梁在多层砖混结构房屋中的应用

作者着重的对设计中采用的槽模圈梁在施工中的复杂性提出了简便易行的施工工艺,是一项较好的新技术,本文由浅入深的论述了一些实际应用的效果。     

An Excitative Control in Operating Process for Synchronous Motor

Aimed at the excitative control for synchronous motor, based on main adjust for power factor and aided adjust for power angle,a kind of new control strategy is presented in this paper. In the steady running,the excitation current will be adjusted in keep. power factor constant,and in dynamic running,it will be calibrated by means of power angle when the disturbance happened.For specified object,the improved algorithm of artificial intelligence controller is also presented in the paper,the simulation result shows that the control algorithm is satisfactory.     

THE CALCULATION OF THE LNS INDEX OF LARGE GENERATORS USING PIECEWISE ALGORITHM BY CAPACITIES

If generator capacity were not graded, the error in reliability evaluation would increase along with the large-capacity generators put into use.In this paper, the method for calculating LNS Index of generators is analyzed and studied using piecewise "algorithm by capacity, it can be used in reliability evaluating of unspecified under loaded generators.     

Discussion on the Hydraulic Calculation Method of Loop Heating Pipe Network

The authors definitely make out the concept of loop main pipeline, supplying main pipeline and ramiform branch line, as well as the order of their hydraulic calculation. Then they puts forward the principia of how to study out the direction of loop main pipeline and presents the method of making flux initial distribution. The matrix of loop main pipeline hydraulic square dispersion is set up. The node referenced pressure is defined and the equation of how to calculate it is deduced. A software is developed to calculate the loop main pipeline hydraulic square dispersion. The method of calculating ramiform branch margin impetus is given.     

Analysis of the Temperature Limit of Dynamic Water Intake of Open loop Surface Water Source Heat Pump Systems

Energy consumption of water intake is one of the key factors for energy saving in the application of the open loop surface water heat pump system. An energy efficiency ratio coupling model for open loop surface water source heat pump systems was established on the basis of the energy consumption model for the water intake and the heat pump units. According to energy saving rate and regulation of energy consumption of water intake, dynamic temperature limits of water intake in different water supply temperature of cooling tower and different pump head were proposed so as to find a calculation method of temperature limits of water intake of open loop surface water heat pumps. Moreover, the energy saving rate of surface water source heat pump systems compared with traditional air conditioning systems under various condition was also calculated.