基于正交试验分析影响透水混凝土性能的主要因素

透水混凝土作为一种环保型材料,在水利工程和道路工程等方面得到越来越广泛的应用。影响其性能的主要因素有：水灰比、骨灰比和骨料粒径。采用正交试验方法[L9（3^4）],以28d抗压强度和透水系数为性能指标,分析研究了3个因素及其不同的水平对透水混凝土性能的影响,并通过回归分析和极差方差分析确定抗压强度和透水系数影响因素的显著性大小,得出了骨料粒径和骨灰比对透水混凝土性能的影响较为显著,水灰比影响较小的结论。     

种草和施用聚丙烯酰胺对荒坡紫色土抗剪和抗蚀性能的影响研究

为探究种植草类和施用聚丙烯酰胺(PAM)对荒坡紫色土抗侵蚀性的影响,尤其是对其抗剪和抗蚀性能的影响,选取狗牙根和三叶草进行盆栽试验,设计了对照、单植草类、单施PAM和复合措施(“草类+PAM”)4类处理开展研究,测定了根系指标和土壤理化性状指标,计算了土壤的抗剪强度指标和抗蚀性指标。结果表明,狗牙根和三叶草根系均能显著降低土壤容重、提高土壤孔隙度和有机质含量(P<0.05),有效增强土壤的抗剪和抗蚀性能;施加PAM能有效促进上述草类各径级根系的生长,显著改善土壤的微结构(P<0.05),尤其是非毛管孔隙度(单施PAM为CK的1.15~1.31倍),提高土体抗剪强度及内摩擦角φ,增大粒径>0.25 mm、>0.5 mm的水稳性团聚体含量、平均重量直径和几何平均直径等抗蚀性指标;PAM对荒坡紫色土抗剪和抗蚀性能的增强效果存在最优浓度;草类根系对土壤抗剪性能的影响较抗蚀性能明显,能显著提高土体的抗剪性能(P<0.05),尤其是增大土壤粘聚力;PAM对土壤抗蚀性能的影响较抗剪性能明显,能显著促进土壤团聚体大颗粒的形成和小颗粒的减少,显著提高土壤团聚度和改善土壤团聚结构等(P<0.05);较单一措施,“草类+PAM”对荒坡紫色土抗剪和抗蚀性能的增强效果最为明显,其中狗牙根与30 g·m^-3的PAM混施时效果最优;0相似文献   

草坪草茎建植技术及管理

用草坪草茎建植草坪是草坪绿地无性繁殖的重要方法。改草皮铺植为草茎播植,并采用机械收集、加工草茎,贮存草茎,人工撒播,精细管理的方法繁殖草坪。这种方法人工费较少,运输量小,播种简单,繁殖系数高,成坪快,坪用性状好,成本低,值得推广应用。     

Mitogen-activated protein kinase is involved in the changes of intracellular free calcium concentration induced by wound exudate in cultured rat epidermal stem cells

AIM: To observe the effects of harvested wound exudate on intracellular free Ca²⁺ in epidermal stem cells (ESCs) in vitro, and to investigate the relationship between mitogen-activated protein kinases (MAPKs) signal pathways and Ca²⁺ mobilization in this condition.METHODS: Wound exudate was harvested from the 80 full-thickness wounds produced on both sides of the back in 40 adult Wistar rats. ESCs were isolated, purified from neonatal Wistar rats by referring to the formerly records and binding our ideas. When the cultured cells showed up clone growing, they were divided into five groups as follows: group A: control group (no-treatment); group B: only treatment with wound exudate; group C: treatment with wound exudate and PD98059; group D: treatment with wound exudate and SB203580; group E: treatment with wound exudate, PD 98059 and SB203580. Then, the cells were incubated with fluorescence Ca²⁺ dye fluo-3/AM at 37 ℃ for 30 min, and measured by using laser scanning confocal microscope.RESULTS: The results showed that the fluorescent intensity of group B was higher than that in group A. A phenomenon of calcium oscillation was found in group C and group D. Furthermore, a rapid decrease of fluorescent intensity was observed in the cells that were preincubated with PD98059 and SB203580 at the same time. CONCLUSION: Based on above results, we propose that wound exudate can directly induce an increase in intracellular free Ca²⁺concentrations of ESCs. MAPKs signaling pathway has an important function of feedback regulation for free Ca²⁺ mobilization of ESCs in this condition, and also is capable of affecting the biological behaviour of epidermal stem cells.     

寒地早粳稻秆部性状与产量关系的研究

针对寒地特殊的生态环境,以180份不同基因型早粳稻为材料,较系统地探讨了秆部性状与产量及产量构成因素之间的相互关系。研究表明:在节间长度配置上,在一定范围之内,控制倒3节间长度、增加倒1、倒2节间的长度有利于提高产量,并且对倒1、倒3节间长的选择是最为有效的。在节间粗度配置上,在保证倒1节间粗的基础上,增加其下部节间的粗度有利于高产。增加基因型的基部节间重、单位茎鞘长干重、单株干重是有利于高产的。适当增加株高和秆长来提高生物产量可能是今后水稻超高产育种的发展方向。在进行茎部性状综合评价时,基部节间重、倒2节间粗、单位秆长干重和穗颈节长4个因子就足以代表12个茎部性状的全部信息量。     

简述钢管混凝土

介绍了钢管混凝土结构的特点、研究现状及其工程应用。     

吲哚丁酸和萘乙酸在茶树短穗扦插上的应用效果

用不同浓度的吲哚丁酸(IBA)和萘乙酸(NAA)组合处理茶树短穗,进行扦插,结果表明:IBA和NAA及其交叉组合对扦插成活率、发根率、发根条数的差异均未达到显著;IBA对最长根长的效果显著,且IBA40×10-6明显优于其他浓度处理。     

Correlation Analysis on the Fineness and Single Fiber Strength of Alpaca Wool Fiber

In this study,321 samples were tested to evaluate the correlation between fineness and single fiber strength of alpaca fiber. The results showed that fineness average of lateral part was 24.30 μm,subject range was from 18.01 to 27.00 μm,accounted for 72% of the total samples;The strength average was 8.31 cN,subject range was from 5.01 to 11.00 cN, accounted for 88% of the total samples, it showed that the overall fineness of alpaca wool fiber was fine,the strength could satisfy the textile technology. The correlation results showed that the fineness of different parts (neck, shoulder, thigh, abdomen, lateral and back) in different groups (sex, age) all reflected that the wool fiber of the back was the finest,the strength was the minimal;And that of abdomen was the thickest,the strength was the maximum. On the other hand, we knew the greater the strength, the fineness was thicker; The smaller the strength, the fineness was finer from the distribution of different fineness range corresponded to the strength. In addition, there was also a positive correlation between them in differernt groups (sex,age),the fineness of adult alpaca was thicker than yearling alpaca, the male alpaca was thicker than female alpaca; The strength of adult alpaca was stronger than yearling alpaca, the male alpaca was stronger than female alpaca. The above results showed that the fineness of alpaca wool fiber was positively correlated with the single fiber strength.