缩短更换35 kV高压熔断器时间

电压互感器是把高电压按比例关系变换成100V或更低等级的标准二次电压,供保护、计量、仪表装置取用,是电力系统重要的一部分。而为了保护电压互感器不受损坏,加装了高压熔断器。高压熔断器会因为系统过电压、电压互感器自身绝缘损坏等因素发生熔断。高压熔断器的组成部件:封盖、弹簧、高压熔断器、绝缘套管、卡子、螺丝。QC 小组对公司2016年11月至2017年1月的8次电压消失原因调查发现,由二次回路故障导致的1 次,占比12%,因为高压熔断器熔断导致的7次,占到了88%。由此可见高压熔断器熔断占的比重较大。     

ZTR割草机自动变割幅结构及控制系统设计

针对零转弯半径(ZTR)割草机割幅宽度固定、无法适应复杂的作业环境的问题,研发了一种可以自动变割幅的割草器,在1.2m割幅的WBZ12219K-S ZTR割草机的基础上,在主刀盘两侧分别增加一个副刀盘。副刀盘主要由割刀、连接板、伺服电动推杆及曲线槽等组成,通过伺服电动推杆的伸缩,控制副刀盘的旋转,以达到变割幅的目的。工作时,通过图像识别技术识别出前方障碍物信息,判断出障碍物间距,将该间距进行区分做出相应的对策,并经由串口通信协议传递给PLC,然后控制割幅的变化,可以实现1.2~1.8m无极自动变割幅。     

劳均可负担耕地面积与机械化程度的关系研究

在已有研究成果的基础上,系统研究了劳动力可负担的耕地面积与机械化程度之间的关系,并对数据采集与处理进行了探讨,建立了平均各劳动力可负担耕地面积与农业机械化程度的关系模型。通过对黑龙江省红星隆分局八五四农场10个生产队100个劳动力调研,在此基础上并对数据进行了处理,得出农业机械化程度是100%和0时,平均每个劳动力可负担的耕地面积分别是4. 95hm^2和1. 45 hm^2。最后通过建立的模型,得出了平均各劳动力可承担的耕地面积在不同农业机械化程度下的数值大小。     

林木种苗在防护林建设中的重要性分析

本文在有关学者的研究基础上,分析了防护林的概念以及建设防护林需要的技术分析, 进而阐述了林木种苗在防护林建设中的重要作用,并提出了提高林木种苗培育的对策建议,以 期能够促进我国防护林的不断发展建设与可持续发展。     

Comparative study of the stoichiometric characteristics of karst and non-karst forests in Guizhou,China

Carbon (C), nitrogen (N), and phosphorous (P) levels and their stoichiometry in plant components (leaves, branch trunks, roots) of trees in a karst forest and non-karst forest are compared. The results show that the C contents, C:N and C:P ratios of dominant species in the karst forest were lower than those in the non-karst forest, but the N and P and the N:P ratio were higher;C:N:P ratios in plant organs of trees in the karst forest were in the order of trunks>roots>branches>leaves. However, C:N:P ratio in the non-karst forest trees were trunks>branches>roots>leaves. Moreover, ratio of C:N:P in trunks was highest and lowest in leaves in both forests. In non-karst forest trees, N:P was in the order of leaves> roots>branches>trunks. There were no significant differences in the ratio of N:P in different plant components of trees in the karst forest. However, in karst and non-karst forest trees, the ratio of N:P in leaves was highest;positive correlations between N and P contents, and N and N:P ratios were observed in both karst and non-karst forests (p<0.001). Negative correlations between P and N:P ratios (p<0.05) were observed in karst forest trees, while positive correlations were observed in non-karst forest trees.     

短期干旱胁迫下棉花气孔表现及光合特征研究

研究气孔对干旱胁迫的响应有助于了解气孔调节真实行为和提高水分利用效率。本研究以‘国欣9号’为供试棉花品种,在人工气候室利用营养液培养,设置加入PEG-6000浓度为0（对照）、1.5%、3.0%和4.5% 4个处理,处理后1~7 d每隔1 d连续测定其气孔形态、光合和叶绿素荧光指标。结果表明：加入PEG-6000 1 d后,随着处理进程的延长,棉花叶片水势、气孔长度、宽度和开度、净光合速率（P_n）、气孔导度（G_s）、蒸腾速率（T_r）、胞间CO₂浓度（C_i）、最大光化学效率（F_v/F_m）和实际光化学量子产量（Yield）均呈下降趋势,气孔密度和非光化学淬灭系数（NPQ）呈上升趋势;不同处理之间,随着干旱胁迫程度增加,也表现出相似趋势。处理后5 d和7 d,与正常处理相比,1.5%、3.0%和4.5%处理棉花气孔长度、宽度、水势、P_n、G_s、T_r和C_i均差异显著（P<0.05）,气孔长度降低幅度最小（1.17%~2.61%）,G_s降低幅度最大（61.62%~69.09%）,T_r降低幅度为37.62%~67.48%。相关分析表明,棉花气孔长度、宽度和开度之间极显著正相关（P<0.01）,气孔宽度和气孔密度不相关。气孔长度、宽度和开度与P_n和Yield极显著正相关（P<0.01）,与NPQ极显著负相关（P<0.01）,与G_s、T_r和F_v/F_m相关不显著。综上,棉花在PEG-6000诱发干旱后,通过降低气孔开度和增大气孔密度降低净光合速率和气孔导度,叶绿素荧光指标Yield和NPQ比F_v/F_m对干旱更敏感。     

The effects of rock fragment content on the erosion processes of spoil heaps: a laboratory scouring experiment with two soils

Journal of Soils and Sediments - Spoil heaps on newly engineered landforms create extensive artificially accelerated erosion, especially when there are catchment areas above spoil heaps, erosion...     

不同地域来源牡丹的亲缘关系分析

【目的】探究西南牡丹品种群与不同种源牡丹品种的亲缘关系,为其栽培起源研究提供基础资料。【方法】以50个中原牡丹品种、20个西南牡丹品种、18个西北牡丹品种、6个国外牡丹品种、1个江南牡丹品种和2个野生种共计96份不同地理种源牡丹为材料,利用36个目标起始密码子多态性(start codon targeted polymorphism,SCoT) 引物进行PCR扩增,筛选多态性比率好的条带,利用NTSYS-pc软件计算品种间的遗传相似性系数,在此基础上,采用UPGMA聚类分析个体间的亲缘关系。【结果】多态性好的引物共有18个,用其对96个牡丹样本进行扩增,共获得182条扩增条带,其中多态性条带172个,多态性比率为94.50%;96个样本间的遗传相似性系数在0.552 3~0.868 1,品种间遗传差异较大,其中遗传相似性系数最大的是西北牡丹品种2与品种3,而紫斑牡丹与豆绿和中甸紫2的遗传相似性系数最小。在遗传相似性系数为0.693 1时,96个牡丹样本聚为8支,第1支由15个中原牡丹品种、4个西南牡丹品种和1个江南品种组成;第2支由2个西南牡丹品种丽江紫3和昭通粉1组成;第3支由35个中原传统牡丹品种聚成;第4支包括3个日本品种、1个法国品种和14个西南品种;第5支由17个紫斑牡丹杂交品种聚成;第6支仅有紫斑牡丹1个样本;第7支仅有黄牡丹1个样本;第8支由美国品种海黄和法国品种金晃聚成。【结论】西南牡丹品种与日本牡丹关系最近,与中原牡丹也有着近缘关系,而与其他种源的品种群关系较远。产地对西南牡丹品种的亲缘关系影响较大。     

伊犁马对补喂α-酮异己酸的吸收及其某些相关代谢的研究

为探究伊犁马对补喂不同水平α-酮异己酸的吸收及其某些相关代谢,采取单因素多水平试验设计方法,选取20匹年龄为1岁,体重(295.25±25.15)kg的伊犁马,分成4组,每组5匹。试验Ⅰ、Ⅱ、Ⅲ组分别补喂6、12、18 gα-酮异己酸,进行为期25 d的试验。在试验第25天采集血液样品。结果表明:(1)随着α-酮异己酸补喂水平的增加,血浆中α-酮异己酸浓度的变化呈先上升后下降的趋势。与对照组相比,补喂α-酮异己酸1 h后各试验组血浆α-酮异己酸浓度分别提高了11.2%、7.86%和21.51%,且均达到了峰值(P>0.05);(2)随着α-酮异己酸补喂水平的增加,血浆中β-羟基-β-甲基丁酸浓度的变化呈先下降后上升再下降的趋势。与对照组相比,各试验组补喂前0 h血浆β-羟基-β-甲基丁酸浓度呈下降趋势,补喂后1、2、4 h血浆β-羟基-β-甲基丁酸浓度均有所升高(P>0.05);(3)与对照组相比,各试验组血浆α-酮异己酸和β-羟基-β-甲基丁酸浓度均差异不显著(P>0.05);试验Ⅱ组和试验Ⅲ组血浆亮氨酸浓度分别提高了22.40%和22.24%(P>0.05);试验Ⅰ组和试验Ⅲ组血浆异亮氨酸浓度极显著降低(P<0.01);血浆缬氨酸浓度显著降低(P<0.05);试验Ⅲ组血浆赖氨酸、甲硫氨酸、精氨酸和谷氨酰胺浓度均显著降低(P<0.05);各试验组血浆5-羟色胺浓度极显著降低(P<0.01);试验Ⅲ组血浆三甲基组氨酸浓度降低了18.74%(P>0.05)。补喂α-酮异己酸提高了伊犁马血浆α-酮异己酸浓度,且各试验组均在补喂后1 h达到峰值;提高了血浆β-羟基-β-甲基丁酸和亮氨酸的浓度。通过补喂不同水平的α-酮异己酸,改变了伊犁马对某些氨基酸的吸收利用。     

A Lymphoid Organ Specific Anti-Lipopolysaccharide Factor from Litopenaeus vannamei Exhibits Strong Antimicrobial Activities

Different shrimp species are known to possess apparent distinct resistance to different pathogens in aquaculture. However, the molecular mechanism underlying this finding still remains unknown. One kind of important antimicrobial peptides, anti-lipopolysaccharide factors (ALF), exhibit broad-spectrum antimicrobial activities. Here, we reported a newly identified ALF from the shrimp Litopenaeus vannamei and compared the immune function with its counterpart in the shrimp Fenneropenaeus chinensis. The ALF, designated as LvALF8, was specifically expressed in the lymphoid organ of L. vannamei. The expression level of LvALF8 was apparently changed after white spot syndrome virus (WSSV) or Vibrio parahaemolyticus challenges. The synthetic LBD peptide of LvALF8 (LvALF8-LBD) showed strong antibacterial activities against most tested Gram-negative and Gram-positive bacteria. LvALF8-LBD could also inhibit the in vivo propagation of WSSV similar as FcALF8-LBD, the LBD of LvALF8 counterpart in F. chinensis. However, LvALF8-LBD and FcALF8-LBD exhibited apparently different antibacterial activity against V. parahaemolyticus, the main pathogen causing acute hepatopancreatic necrosis disease (AHPND) of affected shrimp. A structural analysis showed that the positive net charge and amphipathicity characteristics of LvALF8-LBD peptide were speculated as two important components for its enhanced antimicrobial activity compared to those of FcALF8-LBD. These new findings may not only provide some evidence to explain the distinct disease resistance among different shrimp species, but also lay out new research ground for the testing and development of LBD-originated antimicrobial peptides to control of shrimp diseases.