激光深熔焊接小孔内等离子体的反韧致辐射吸收研究

在假设小孔为圆柱形的基础上，通过跟踪光线在小孔内的多次反射轨迹，对激光深熔焊接过程中小孔内等离子体的反韧致辐射吸收进行了研究，计算了小孔孔壁上吸收的激光功率密度，分析研究了孔壁的多次反射次数、聚焦透镜的焦距以及小孔直径等因素对孔壁上的激光功率密度分布的影响．计算结果表明：小孔孔壁通过等离子体的反韧致辐射吸收的激光功率密度主要取决于等离子体对直射激光的反韧致辐射吸收，小孔孔壁的多次反射光只对小孔下部孔壁的激光功率密度分布有一些影响．随着聚焦透镜焦距的增大，小孔孔壁上吸收的激光功率密度峰值减小，但分布区域向小孔深处推移．最后，对小孔孔壁上吸收的激光功率密度与小孔的尺寸之间的关系进行了讨论．小孔的尺寸取决于孔壁上吸收的激光功率密度大小．激光功率密度越大，小孔直径越大。     

拍翅运动诱发肉鸡胸深肌病的血清肌酸磷酸激酶（CPK）水平的变化

强迫ＡＡ肉鸡拍翅运动诱发胸深肌病并测定了诱发过程中试验鸡和对照鸡的血清肌酸磷酸激酶（ＣＰＫ）水平的变化。试验组鸡５天中共拍翅７次，有４／９例发生典型胸深肌病。病变特征为带有绿色坏死区的坏死性肌炎。对照组鸡不拍翅，不发生胸肌坏死。血清ＣＰＫ水平测定表明，试验组ＣＰＫ水平在拍翅后２４小时升高并维持四天，直到实验结束，与对照组保持极显著差异，说明ＣＰＫ是鸡运动应激有实用意义的血清酶指标，测定时间宜在运动后２４小时进行，与猪应激后的情况相似。在试验组内，ＣＰＫ水平仅在０—２天，０—３天，１—２天，１—３天对比组合之间有极显著差异，进一步说明运动应激后２４小时，４８小时之内为测定ＣＰＫ的可选择时间。但发病鸡与不发病鸡的ＣＰＫ水平无显著差异，说明ＣＰＫ水平虽能指示运动应激，却不能揭示胸肌病的发生，对其原因作了简要讨论。     

高校思想政治理论课教学面临的问题与对策

当前，思想政治理论课新方案正在全国高校实施，如何在新课程教学中提高思想政治理论课教学的实效性，使思想政治理论课成为学生受欢迎的课程，这是思想政治理论课教学必须长期解决的一个问题。结合思想政治理论课新方案的实施，就教学中面临的问题进行了分析，并提出解决问题的对策。     

论“学会学习”

21世纪是知识经济的世纪,信息技术已使社会发生深刻的变革,必然带来学习的革命,21世纪是终身学习的世纪,人人都要学会学习。     

Carabids (Coleoptera: Carabidae) in a forest patchwork: a connectivity analysis of the Bereg Plain landscape graph

For many species, one important key to persistence is maintaining connectivity among local populations that allow for dispersal and gene flow. This is probably true for carabid species (Coleoptera:Carabidae) living in the fragmented forests of the Bereg Plain (NE Hungary and W Ukraine). Based on field data, we have drafted a landscape graph of the area representing the habitat network of these species. Graph nodes and links represented two kinds of landscape elements: habitat (forest) patches and corridors, respectively. The quality of habitat patches and corridors were ranked (from low (1) to high (4)), reflecting local population sizes in the case of patches and estimated permeability in the case of corridors. We analysed (1) the positional importance of landscape elements in maintaining the connectivity of the intact network, (2) the effect of inserting hypothetical corridors into the network, (3) the effects of improving the quality of the existing corridors, and (4) how to connect every patch in a cost-effective way. Our results set quantitative priorities for conservation practice by identifying important corridors: what to protect, what to build and what to improve. Several network analytical techniques were used to account for the directed (source-sink) and highly fragmented nature of the landscape graph. We provide conservation priority ranks for the landscape elements and discuss the conditions for the use of particular network indices. Our study could be of extreme relevance, since a new highway is being planned through the area.     

氟神经毒性的研究进展

氟中毒能够引起神经系统的损伤,针对氟的神经毒性作用,从各个方面阐述氟对脑组织的影响,包括神经细胞的形态结构、脂质过氧化、自由基、DNA损伤等。高氟可以降低人及动物的学习记忆能力,引起儿童智商低下,指出研究氟神经毒性的重要性。     

和谐高校人力资源构建模式探讨

高校人力天生具有独立性、非共生性，导致高校人力资源利用的低效性、排他性、延滞性。平等是构建同一情感层面交往、对话的空间和质量的基础。合作意味着工作中的每个人共同学习工作，共同解决问题，相互从合作中受益，共同获得发展。民主化管理，是让员工投入最少的时间和个人的辛劳，学校花费更少的资金和财物，创造更大的效益，完成集体目标，尊重个体权利与自由的同时强调民主管理中集体的文化内涵和伦理道德，从而构建和谐的人力资源环境，和谐的校园氛围，和谐的学校教育。     

基于深度学习的大豆豆荚类别识别研究

Crop phenotype investigation is a key task in the selection and breeding of crop varieties. The traditional phenotypic survey mainly relies on human labors, which makes the results of the phenotypic survey difficult to meet the requirements of automation, high precision and high reliability. In the investigation of soybean phenotypes, the correct identification of pod types is the key and premise for the accurate extraction of phenotypes such as the number, length and width of pods. This study focused on the pictures of mature soybean pods by using deep learning to migrate five different network models [AlexNet, VggNet (Vgg16, Vgg19), GoogleNet, ResNet-50], to identify one-pod, two-pod, three-pod, and four-pod. In order to improve training speed and accuracy, this experiment fine-tuning the model and selected different optimizers (SGD, Adam) to optimize the network model. Adam’s performance was better than SGD in the problem of pod identification. With the Vgg16 network model and the Adam optimizer, the test accuracy of the pod category reached 98.41%, which reflected the best performance in the selected network model. In the 10-fold cross-validation test, the Vgg16 network model had good stability. Therefore, this study indicates that the Vgg16 network model can be applied to the actual identification of pods, and provide an important solution for further automatic extraction of pod phenotypes.     

Influence of Thawing Diluents on Vitality,Acrosome Morphology,Ultrastructure and Enzyme Release of Deep Frozen Roar Spermatozoa*

The present investigation was performed to study the effect of freezing and thawing on boar spermatozoa. Thirty-one ejaculates from four boars were investigated after thawing in three different thawing diluents (seminal plasma, OLEP, isotonic glucose solution).From each ejaculate one sample of 1 × 10⁹ spermatozoa was thawed in each of the thawing diluents. Each sample was examined in a thermoresistance test in which motility was stimulated with caffeine 30 min. and 3 hrs. after thawing. Furthermore, acrosome morphology and ASAT release from the spermatozoa were investigated for each sample. One ejaculate from the two most frequently used boars was examined by electron microscopy after thawing in each of the thawing diluents.Differences in the aspects studied appeared between isotonic glucose solution and the other two thawing diluents in the thermoresistance test, in the response to caffeine stimulation 3 hrs. after thawing and in the amount of ASAT released from the spermatozoa. The influence on the acrosome morphology varied between the thawing diluents, but the acrosomal alterations did not seem to be connected with the damage reflected by the thermoresistance test and by the measurement of extracellular ASAT activity.The ultrastructural investigation showed that all spermatozoa examined had some degree of ultrastructural alteration as compared with freshly ejaculated boar spermatozoa treated in the same way. This alteration could not be related to any of the thawing diluents.Of the various laboratory tests the thermoresistance test and the measurement of ASAT release are suggested to be sensitive indicators of sperm damage during freezing and thawing. These tests might be useful indicators of variations in sensitivity of spermatozoa to the freezing-thawing procedure.     

Fertility of deep frozen boar spermatozoa at various intervals between insemination and induced ovulation: influence of boars and thawing diluents.

The fertilizing ability of deep frozen boar spermatozoa was assessed after artificial insemination at various intervals after human chorionic gonadotropin (HCG) induced ovulation in gilts. Boar seminal plasma and OLEP were used as thawing diluent agents. The fertilization rates were similar when insemination was performed 2 or 6 hours before the time of estimated ovulation (40 hours post-HCG administration). However, fertility rates markedly declined when insemination was performed earlier than 6 hours before expected ovulation. In inseminations performed 2 hours before ovulation, the fertility rate was higher with specimens treated with boar seminal plasma diluent than with OLEP. As the difference between the time of insemination and that of ovulation increased, the difference in fertilizing ability of spermatozoa from the 2 boars used also increased. The results show that spermatozoa which have a low resistance to freezing-thawing also have a diminished fertile life in the female genital tract.