丝绸之路经济带背景下林业生态型城市建设的研究

新疆的特殊地理环境与政治地位决定了其在丝绸之路经济带的核心地位,只有将其城市建设成为生态宜居的林业生态型城市,才能产生更大的人才聚集力,促进更频繁的经济交流活动,发挥其最大的城市功能。该研究提出了建设城市生态社区、建立城市林业生态屏障、引入海绵城市理念、建设低碳型城市4种方式进行林业生态型城市建设,使城镇化快速发展与有限的生态资源相平衡。     

北京海淀区道路绿地非生长季地表覆盖特征研究

在非生长季,城市绿地中地表覆盖物在缓解空气颗粒物污染方面起到重要作用。文章以北京市海淀区道路绿地作为研究对象,使用分层抽样的方法选出37条道路作为道路样本进行实地调查,分析了非生长季地表覆盖特征及影响要素,初步得到以下结论:(1)复合覆盖模式比单一覆盖模式绿地的灌草及地表覆盖率高,超过15个百分点,且覆盖面积超过80%。(2)非生长季灌草及地表覆盖率分别为76.9%和68.94%。有约30%道路绿地是裸露的,较生长季的45%有所改善。(3)灌草覆盖率超过80%的绿地单元数量占绿地单元总数的37.72%,超过60%的绿地单元数量占绿地单元总数的53.51%,两者都低于生长季;而地表覆盖率超过80%的绿地单元数量占绿地单元总数的23.68%,超过60%的绿地单元数量占绿地单元总数的40.35%,都显著高于生长季。(4)海淀区道路绿地地表覆盖质量整体较好,但四环-五环的绿地区域存在盲区,地表覆盖质量差。最后,文章分析了造成海淀区道路绿地地表土壤裸露的原因,以及养护管理方面存在的问题,并提出生态养护等相关建议。     

前混合磨料射流磨料速度测试的新方法

前混合磨料射流超强的打击力主要是由高速磨料群提供的,因此,磨料速度测试是磨料打击力分布规律等研究的基础。针对传统研究方法的不足之处,笔者提出采用PIV技术结合自主编程设计的磨料中心识别程序,实现非接触式测试手段下磨料速度测试实验研究,并利用该方法简要分析了喷嘴结构对磨料速度的影响。结果表明,在一定范围内增加直线段长度有利于提高喷嘴出口处磨料的速度,表明在喷嘴直线段末端磨料依然处于明显的加速状态;增加收敛段长度对提高喷嘴出口处磨料速度有一定的作用,但磨料速度增幅不大;收敛角较大时,液相在收敛段前半段加速缓慢而在后半段过于剧烈,因磨料颗粒加速滞后于液相的原因导致喷嘴出口处磨料速度降低。     

Uterine biology in pigs and sheep

ABSTRACT: There is a dialogue between the developing conceptus (embryo-fetus and associated placental membranes) and maternal uterus which must be established during the peri-implantation period for pregnancy recognition signaling, implantation, regulation of gene expression by uterine epithelial and stromal cells, placentation and exchange of nutrients and gases. The uterus provide a microenvironment in which molecules secreted by uterine epithelia or transported into the uterine lumen represent histotroph required for growth and development of the conceptus and receptivity of the uterus to implantation. Pregnancy recognition signaling mechanisms sustain the functional lifespan of the corpora lutea (CL) which produce progesterone, the hormone of pregnancy essential for uterine functions that support implantation and placentation required for a successful outcome of pregnancy. It is within the peri-implantation period that most embryonic deaths occur due to deficiencies attributed to uterine functions or failure of the conceptus to develop appropriately, signal pregnancy recognition and/or undergo implantation and placentation. With proper placentation, the fetal fluids and fetal membranes each have unique functions to ensure hematotrophic and histotrophic nutrition in support of growth and development of the fetus. The endocrine status of the pregnant female and her nutritional status are critical for successful establishment and maintenance of pregnancy. This review addresses the complexity of key mechanisms that are characteristic of successful reproduction in sheep and pigs and gaps in knowledge that must be the subject of research in order to enhance fertility and reproductive health of livestock species.     

适于木材种类识别颜色空间的研究

为了确定适合木材种类识别的颜色空间,分别在RGB、HSV、L^＊a^＊b^＊、I1I2I3和归一化T五个常用颜色空间中,获取了木材样本的颜色直方图和颜色矩特征,并进行了识别试验。结果表明,HSV是最适合木材种类识别的颜色空间。     

Classification of ultra high frequency partial discharge signalsin gas insulated switchgear based on complex wavelet transform

In order to classify the ultra high frequency (UHF) partial discharge (PD) signals resulting from four types of insulation defects in gas insulated switchgear (GIS), the complex wavelet transform is applied to extract features of UHF PD signals. Five statistical parameters including mean, variance, kurtosis, skewness and energy are used to quantize the scaling coefficients of the complex wavelet transform and describe the feature subsets of UHF PD signals.A critical index J is defined to select features according to their classification performance. Using the J criterion, five optimal features are selected from sixty UHF PD features and taken as the input of radial basis function neural network. The classification results show that the information of real part and image part of complex wavelet coefficients indicates the characteristics of UHF PD singles and the recognition effect is pretty good. To use db4 complex wavelet can get the best classification performance.     

Identification and Characterization of a Novel Lectin from the Clam Glycymeris yessoensis and Its Functional Characterization under Microbial Stimulation and Environmental Stress

Lectin from the bivalve Glycymeris yessoensis (GYL) was purified by affinity chromatography on porcine stomach mucin–Sepharose. GYL is a dimeric protein with a molecular mass of 36 kDa, as established by SDS-PAGE and MALDI-TOF analysis, consisting of 18 kDa subunits linked by a disulfide bridge. According to circular dichroism data, GYL is a β/α-protein with the predominance of β-structure. GYL preferentially agglutinates enzyme-treated rabbit erythrocytes and recognizes glycoproteins containing O-glycosidically linked glycans, such as porcine stomach mucin (PSM), fetuin, thyroglobulin, and ovalbumin. The amino acid sequences of five segments of GYL were acquired via mass spectrometry. The sequences have no homology with other known lectins. GYL is Ca²⁺-dependent and stable over a range above a pH of 8 and temperatures up to 20 °C for 30 min. GYL is a pattern recognition receptor, as it binds common pathogen-associated molecular patterns, such as peptidoglycan, LPS, β-1,3-glucan and mannan. GYL possesses a broad microbial-binding spectrum, including Gram-positive (Bacillus subtilis, Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli, Vibrio proteolyticus), but not the fungus Candida albicans. Expression levels of GYL in the hemolymph were significantly upregulated after bacterial challenge by V. proteolyticus plus environmental stress (diesel fuel). Results indicate that GYL is probably a new member of the C-type lectin family, and may be involved in the immune response of G. yessoensis to bacterial attack.     

浅议开发区道路景观设计——以江阴开发区西区花港路景观设计为例

对开发区道路景观设计进行了初步的研究与探讨,并以江阴开发区西区花港路为例,具体介绍了开发区道路景观的设计理念、原则和特点。     

A Visibility Designing Method Based on Luminance Uniformity

To determine the influence of luminance uniformity on visibility levels, and to study methods of visibility design, we carried out experiments having different luminaire collocation modes. Cut off luminaire and semi cut off luminaire were used in these experiments. The relationship of luminance uniformity and visibility level distribution of targets was studied based on small target visibility calculation methods. The results indicate that if luminance uniformity is good, the road luminance distribution should remain uniform, then the visibility levels of all targets are positive or negative). If luminance uniformity is insufficient, it can be reduced intentionally and the visibility level of each target can be increased. A higher STV value can be gained for the entire road. The method of limiting road visibility level distribution should be established in road lighting design.     

An artificial immunity based predictive method for neural networks and its applications

A radial basis function (RBF) neural network learning algorithm based on immune recognition was proposed to improve the low forecast precision and the slow convergence speed of such networks. In the algorithm, artificial immunity was used to determine the center and width parameters of the Gauss basis function. The recognized data were regarded as antigens and the compression mapping of antigens were taken as antibodies, i.e., the centers of the hidden layer. The recursion least square algorithm (RLS) was employed to determine the output layer weights. The algorithm improved the convergence speed and precision of the RBF neural networks. The model was applied to the blast furnace of a large iron and steel company. The results show that the model has forecast precision far superior to existing models and requires less training time than they do.