大型地下洞室群施工通风的三维数值模拟

大型地下洞室群的施工通风问题是保证安全、加快施工进度的关键。传统的施工通风设计无法掌控真实通风效果,导致资源浪费。基于流体力学理论的地下洞室群施工通风三维数值模拟,能定量分析大型洞室、关键节点或通风洞(井)等的通风效果,为通风方案的设计和优化提供依据。     

A social learning video method: Identifying and sharing successful transformation knowledge for sustainable soil management in Switzerland

To enhance sustainable land use, a From Farmer to Farmer project was conducted in Switzerland (2001–2010). A multi‐stakeholder discussion group co‐produced nine videos with experienced farmers and wine producers showing sustainable soil management practices. We analysed the video audio‐visual content and drew on reflections of the co‐production process, referring to concepts of system, target and transformation knowledge, as well as on social learning. The analysis showed a broad range of means (or actions) for sustainable soil management in arable land management, fodder production and wine growing that are aligned to transformation knowledge. The research showed that farmers refer to three phases of social learning, light‐bulb moments, coping with challenges and gaining successful expertise. These are not just linear processes of individuals. Four types of social learning were found in the video analysis: (a) learning from observing actions of others, (b) sharing experiences with storytelling, (c) informal social interactions and (d) being a role model with a large social network. Videos enable transformation knowledge to be shared with peers using storytelling; this powerful narrative communication style provides credibility and respects the ‘thought style’ of the target audience group. We conclude that for successful implementation of sustainable actions, it is important to address a specific target group and share their transformation knowledge built upon system and target knowledge. The social learning video method is a viable way to enable social learning between science, administration and practice and has potential for fostering change in sustainable soil management.     

基于三维点云的群体樱桃树冠层去噪和配准方法

樱桃树的栽培密度影响其冠层的光照分布,通过研究群体樱桃树的三维结构,可分析不同栽植密度下温室甜樱桃树冠层光照分布规律,指导樱桃树的科学种植,进而提高甜樱桃产量和品质。高质量的点云数据是构建群体樱桃树三维结构的基础,而点云去噪和点云配准是点云数据预处理的关键环节。本文提出一种基于三维点云的群体樱桃树去噪和配准方法,搭建群体樱桃树三维信息采集平台,使用2台固定的DK深度相机获取群体樱桃树彩色点云数据;提出基于颜色区域生长的二分类方法,设置颜色阈值分割点云并进行二分类处理,可有效去除彩色点云数据中的异常无效点,并设置点云离散度和RGB值,作为点云去噪评价标准;结合人工标记法和双相机位姿矩阵,提出基于颜色特征改进的ICP方法,解决传统ICP配准算法多依赖初始位姿且配准速度较慢的问题。该方法通过对点云粗配准,得到较好的初始位姿,使用SIFT算法提取颜色特征点,将颜色特征与ICP算法结合进行点云精配准,然后使用PCL中随机采样一致性算法,去除错误匹配点,有效减少配准时间,提高配准精度。以夏季和冬季的群体樱桃树20组点云数据为实验对象,对比分析ICP算法、NDT算法、SAC-IA算法和本文配准方法的配准精度和配准时间,结果表明,本文配准方法平均耗时分别为5.01、4.30s,均方根误差分别为2.316、2.100cm,有效减少了配准时间和配准误差,验证了本文算法的有效性和普适性。     

气门组的检测与修理

发动机是汽车、内燃机车、轮船、飞机、农用车辆等机械的重要动力来源。在使用中,气门组容易出现问题,需要检测与维修。     

Detection of repeated genotypes among 93 diploid wheat accessions

Summary An objective procedure was developed to find and eliminate repeated genotypes from a set of crop cultivars or accessions which may be used as parents for future plant breeding programs. Nonhierarchical, nonexclusive, exhaustive cluster analysis was used to group 93 diploid wheat accessions using LSD multiple comparisons of accession means based on data measured on seven characters. Beginning with the rarest accessions, i.e. those represented in the fewest clusters resulting from the clusters analysis, a minimum number of the accessions were chosen to represent the phenotypes of all 93 of the accessions. Two analyses were performed, one using data from an irrigated trial, the other from a dryland trial. The dryland trial data was more discriminating in that it required 71 accessions to represent all of the clusters generated from the original 93 accessions while the irrigated trial data required only 60 of the 93 accessions. In addition to the 71 accessions chosen from the dryland trial analysis, the irrigated trial analysis suggested an additional 12 accessions were phenotypically and, therefore, genotypically unique. The total of 83 unique accessions left 10 phenotypically duplicate accessions to be eliminated from the set of potential parents. Four of the 10 duplicated accessions were rare in that they were represented in very few clusters in either the irrigated trial analysis or in the dryland trial analysis. Because their phenotypes were not unique in spite of being rare, we believe such accessions were duplicated genotypically as well as phenotypically. The other six duplicates were common in that they were represented in a large number of clusters. Such accessions may not prove to be duplicates if grown in additional environments (trials), or if measured on additional characters.     

Development and characterization of common wheat-Thinopyrum intermedium translocation lines with resistance to barley yellow dwarf virus

We developed some wheat-Th. intermedium translocation lines,Yw642, Yw443 and Yw243, etc., showing good BYDV resistance from L1by induced homoeologous pairing using CS ph mutant. Characterization ofthese wheat lines was carried out by GISH and RFLP analysis. The resultsof GISH showed that the lines, YWw42, Yw443 and Yw243, etc., arehomozygous wheat-Th. intermedium translocation lines, in which thechromosome segments of Th. intermedium were transferred to thedistal end of a pair of wheat chromosomes. RFLP analysis indicated that thetranslocation chromosome of the wheat lines is T7DS · 7DL-7XL. Thebreakpoint of the translocation is located on the distal end of 7DL, betweenXpsr965 and Xpsr680 about 90–99 cm from the centromere. The BYDVgene is located on the distal end of 7XL around Xpsr680, Xpsr687 andXwg380. The RFLP markers of psr680, psr687 and wg380 werecosegregated with the BYDV resistance respectively and could be used formolecular assisted selection (MAS) in wheat breeding program for BYDVresistance.     

从协同教育看日本文学精品课程群的建立

日本文学课程作为日语专业高年级阶段课程,在日语专业人才培养中占有重要地位。文章拟从协同教育理论角度出发,探讨日本文学精品课程群的创建模式,旨在为日益繁盛的日本文学课程教学改革模式研究提供可行性参考。     

Cloning and sequence analysis of nine novel MYB genes in Taxodiaceae plants

Myeloblastosis(MYB) is one of the largest transcribed factor families in plants. To gain an overall picture of the evolution of MYB genes in relict plants, we cloned nine novel MYB genes in Taxodiaceae plants(Taxodium distichum, Taxodium ascendens, Cryptomeria japonica var. Sinensis, Cryptomeria japonica cv. Araucarioides, Cryptomer Japonica, Metasequoia glyptostroboides, Cunninghamia lanceolata, Taiwania cryptomerioides and Glyptostrobus pensilis). The deduced amino acid sequences for MYBs showed that the nine MYB proteins contained two DNA binding domains. The first domain is from amino acid position 29 to 78, wherein three tryptophanes at 33, 53 and 73 were separated by 19 amino acids, respectively. The second domain is from amino acid position 82 to 127, wherein three tryptophanes at 86, 105 and 124 were separated by 18 amino acids, respectively, whereas the first tryptophane at amino acid position 86 is replaced by a phenylalanine. The characterization of these conserved domains at nine MYBs indicated that they all belong to the R2R3-MYB group. The secondary structure analysis showed that α-helix and β-turn are the major motifs of the predicted secondary structure of MYBs. The three dimensional model of each MYB protein showed that the structure is like clip, making it more flexible and mobile. The similarities between the nine MYB proteins in Taxodiaceae were calculated. The highest identical value of 99% is between CjsMYB, CjMYB and CjaMYB, whereas the lowest value of 82% is between TaMYB and ClMYB. According to the phylogenetic tree, the distances between different genera were relatively large whereas those within genera were relatively small. As expected, accessions of the same genus formed a subgroup before being grouped with other genera.     

杭州次生湿地中早园竹林的种子库特征

实验通过野外调查和萌发试验对杭州西溪湿地经济竹林的种子库特征进行研究。结果,经济竹林种子库中共出现14科26种植物,其中以十字花科、大戟科、玄参科、菊科和禾本科为主。种子库密度的垂直分布呈下降趋势。其种子库中有劣性杂草如一年蓬和蒲公英,并占有优势。竹林地10~15 cm土壤的板结和贫瘠是种子量稀少的主要原因,竹林大部分是在干扰和干旱生境下萌发的草本和灌木种子库,亦有永久种子库的贡献。     

An approach to determining forest areas with recreational potential: The case of forest areas around main transportation roads in the Maçka Region of Trabzon,Turkey

It is most important to determine areas with recreation potential that can permit sustainable use of forest resources and also meet recreational uses. Under the method described in this study, using the Geographic Information System (GIS), a spatial suitability model for recreational use was combined with a recreational priority perceptual suitability model that depends on principal component analysis (PCA) and is based on the perceptions of both recreational users and experts. Using principal component analysis, five priority components explaining 69.371% of the total variance were identified out of 12 perceptual suitability components. These components are scenic beauty, accessibility, the surface of the landscape, tree type, and forest stand condition. The recreation terrain suitability value of an area with recreational potential was assessed with the assistance of these five priority components. This enabled us to generate a recreation terrain suitability value equation and a recreation terrain suitability value scale for a potential recreation area. This applicability of this approach was demonstrated in the identification of potential recreation areas in Trabzon, Turkey.