国产MJ3210小型木工跑车带锯机锯解正交试验分析   总被引：1，自引：0，他引：1  

王正  蒋华松  卫佩行  何杰  王晓东 《林业机械与木工设备》2009,37(12):17-20

采用正交试验设计法，对国产MJ3210小型木工跑车带锯机的锯解质量进行研究。通过实测马尾松锯材尺寸偏差、表面粗糙度等参数，得到其最佳的进料速度、锯解厚度和锯卡高度的组合方案。结果表明，该设备具有结构简单、出材率高、锯解精度高、质量好、成本低和生产效率高等优点。  相似文献   

外源粪菌干预对受体猪肠道屏障功能的影响研究     

耿世杰  李媛  程赛赛  胡栾莎  岳晓敬  韩新燕 《中国畜牧杂志》2018,(3)

为研究外源粪菌干预对受体猪肠道屏障功能的影响,试验选取初生重相近、胎次相同、同日出生的杜×长×大三元杂交哺乳仔猪12窝,随机分为2组,每组6窝(每窝10~12头)。试验组于1~10日龄隔天灌喂1 m L金华猪粪菌悬液进行外源粪菌干预;对照组灌喂等量无菌0.1 mol/L无菌磷酸盐缓冲液(PBS)。试验期间,仔猪自由哺乳采食和饮水,分别于12日龄和27日龄进行屠宰、采样。结果表明:外源粪菌干预可明显减少腹泻,提高受体猪的平均日增重和成活率(P0.05);外源粪菌干预能显著降低27日龄受体猪肠道隐窝深度(P0.05),显著提高肠道绒毛高度/隐窝深度(P0.05);外源粪菌干预能显著增加肠道杯状细胞数和12日龄肠道分泌型免疫球蛋白A阳性(SIgA~+)细胞数(P0.05),同时显著提高肠道黏蛋白Muc2、紧密连接蛋白ZO-1和Occludin表达水平(P0.05),而27日龄试验组的肠道SIgA~+细胞数与对照组无显著差异(P0.05)。综上可知,外源粪菌干预能通过增加肠道杯状细胞和SIgA~+细胞数、提高黏蛋白和紧密连接蛋白表达的方式调节受体猪肠道屏障功能,具有维持猪肠道功能稳态和促进肠道健康的作用。  相似文献   

Information extraction and dynamic evaluation of soil salinization with a remote sensing method in a typical county on the Huang-Huai-Hai Plain of China   总被引：1，自引：0，他引：1  

Xiaoguang ZHANG  Biao HUANG  Feng LIU 《土壤圈》2020,30(4):496-507

Monitoring the dynamics of soil salinization is of great importance for agricultural production. This study selected Yucheng County, a typical county on the Huang-Huai-Hai Plain (HHHP) of China, as the study area and evaluated the spatial and temporal variation of soil salinization. Three methods, consisting of principal component analysis (PCA) transformation, tasseled cap (TC) transformation, and optimal band combination (OBC), were used to extract information from an early Landsat multispectral scanner (MSS) image from 1984, and their advantages were compared. In addition, OBC was used on a thematic mapper (TM) image from 2009. An iteratively self-organizing data analysis algorithm was used together with prior knowledge of likely classifications to interpret the MSS and TM images for data classification. Finally, a transfer matrix method was used to assess the spatial and temporal variability of soil salinization and analyze the driving factors of soil salinization. Compared to PCA transformation and OBC, TC transformation was a more effective method for extracting soil salinization information from the MSS sensor. The results indicate that a soil area of approximately 298 km² was affected by salinity in 1984 in Yucheng County, of which 5.40%, 11.96%, and 12.75% were classified as being subject to slight, moderate, and severe salinization, respectively. In 2009, the saline area was reduced to only 146 km², of which 10.70% and 3.75% were characterized by slight to moderate salinization and no severe salinization, respectively. The saline land decreased at an average rate of 6 km² per year. This decrease was probably a result of lower groundwater depth, increased organic fertilizer or crop straw in soil, changed land use type, and increased vegetation coverage.  相似文献   

不同生物有机肥施肥方法对压砂西瓜生长及产量的影响   总被引：4，自引：0，他引：4  

谭军利  田军仓  李应海  王西娜 《干旱地区农业研究》2011,29(6):135-138

2009年在宁夏中卫香山乡采用田间试验的方法,比较了穴施和条施生物有机肥对压砂西瓜生长及产量的影响.结果表明:与条施生物有机肥相比,穴施条件下,西瓜生育前期叶面积指数增加了80％ ～ 119％；生育中后期主蔓长20.6 cm,增加25.4％；叶片数也较多；单瓜重增加了43％,中心糖含量和边糖含量分别提高了9％和8％；同...  相似文献   

Controlling Techniques of Channel Sharing in HFC Network     

SHI Jin  ZENG Xi_hua 《保鲜与加工》2002,(3):30-34

The techniques of sharing a channel in HFC are original with regard to those of Ethernet and Ring. In this paper, the analysis is stressed on the method of the upstream bandwidth allocation, the collision resolving, and the relationship among them, beginning with MAP management message. The MAP is a complex frame, in which the messages of ranging opportunity needed by the CM at the access beginning, bandwidth allocation contention, bandwidth allocation and collision detection are included. The access way for a user is explained after the frame format and functions of a MAP are illustrated. Finally, upstream bandwidth allocation, the cause of collision, algorithm and the process to solve the collision and so on are studied.  相似文献   

Balance Order and Interpolatory Property of M-band Multiwavelets     

MAO Yi-bo 《保鲜与加工》2005,(4):116-118

The p order balance and interpolatory property is introduced to M band multiwavelets. Balance conditions for M band multiwavelets are investigated in time domain and frequency domain respectively. The balanced order is equal to its approximation order for M band interpolatory multiwavelet.  相似文献   

各向异性砂土剪切带角度的理论分析     

李学丰  袁琪  马文国 《保鲜与加工》2015,(4):90-96

针对平面应变条件下各向异性砂土剪切带角度的试验规律,采用传统的3种理论和分叉理论进行对比分析。将平面应变条件下剪切带角度的试验结果按照传统3种理论整理发现,尽管传统3种理论可以估算同种砂剪切带角度的极小、中间和极大值,但无法解释其各向异性规律。砂土在平面应变条件下破坏时会产生明显的剪切带,当剪切带方向和砂土沉积面方向接近时,会较早诱发剪切带的产生,使材料强度降低,造成了平面应变条件下各向异性强度规律明显不同于常规三轴条件下的试验规律,采用分叉理论结合各向异性模型则可以有效解释这个规律。随砂土沉积面角度的变化,模型可以从细观角度解释常规三轴条件下剪切带角度的单调变化的试验规律,结合分叉理论可以描述平面应变条件下其先减小然后增大的规律。通过几种理论对比分析表明,模型结合分叉理论不但能够描述多种应力状态下的平面应变和常规三轴应力条件下剪切带角度表现的不同规律,而且能够从细观角度解释其各向异性成因。  相似文献   

拖拉机驾驶室可靠性疲劳试验研究   总被引：1，自引：0，他引：1  

薛念文  周孔亢  陈龙 《农业机械学报》2002,33(6):26-28,11

分析了拖拉机驾驶室的振动环境，提出了一种用定频正弦振动等效模拟窄带随机振动的试验方法，编制了拖拉机驾驶室的室内可靠性疲劳试验载荷谱，达到以较少的试验投入实现拖拉机驾驶室振动环境室内疲劳模拟试验的目的。  相似文献   

云龙河拱坝施工过程的三维有限元     

常晓林  卢建华 《中国农村水利水电》2006,(7):61-63

采用三维弹塑性非线性有限元法，对云龙河拱坝施工过程的实际浇筑、封拱和水库蓄水过程的坝体应力及变形进行了仿真分析，同时分析了施工过程的坝肩层间错层带的变形。计算结果表明施工过程的坝体变形较小，坝体有限元等效应力满足规范要求，坝肩层间错层带错动变形很小，说明大坝结构设计合理，坝肩无错动危险。计算成果为工程项目的实施提供了技术依据，同时对类似工程分析具有借鉴作用。  相似文献   

西方商业银行市场营销     

李义超  白亚丽 《河北北方学院学报(自然科学版)》2000,(3)

西方商业银行在市场营销方面具有丰富的经验。系统介绍了西方商业银行营销的基本内容和现代特征,以求对我国商业银行的健康发展提供一些值得借鉴的经验。  相似文献