一种花生收获机轮边减速器的设计与分析

对一种花生收获机的轮边减速器进行了设计与研究,在总体方案分析的基础上,进行了轮边减速器主要零件基本参数设计,建立了基本的实体模型,并进行了有限元分析,完成了轮边减速器的总体设计。     

广西象州县霜冻发生规律及其应用对策

通过对1956－2001年45个冬季出现在象州县境内的霜冻日进行分析，找出其发生和分布规律，发现霜冻的形成与环流形势，气象因素，地形具有密切的联系，据此对象州县农业产业结构调整提出一些具体的应用对策措施。     

Tillage and land use effects on soil microporosity in Ohio, USA and Kolombangara, Solomon Islands

Micropores are important to soil moisture retention and plant growth. Microporosity and pore size distribution were evaluated using mercury intrusion porosimetery on aggregates from 35-year-old experiments started in 1962 at Wooster (40.5 °N, 82 °W) and South Charleston (39.8 °N, 84 °W) in Ohio, USA and from three land use practices on Kolombangara (8 °S, 157 °E) in Solomon Islands. Tillage treatments in Ohio included: moldboard plowing (MP), chisel plowing (CP), and no-till (NT) with continuous corn. The land use treatments in Kolombangara included: natural forest (NF), traditional farming (TF) and topsoil removal (TR). Pore size measured in aggregates ranged from 0.2 to 100 μm in diameter. Median pore radius was significantly (P < 0.05) larger for NT than for MP and CP treatments at Wooster, but not at South Charleston. Tillage treatments had significant effect on the volume of both storage and residual pores for both sites in Ohio. Volume of storage and residual pores were higher for Wooster than South Charleston soil. At Kolombangara, the NF treatment had significantly larger median and peak pore radii, and microporosity than TF and TR treatments. There was, however, no significant difference among treatments in the volume of pore size distribution. These data support a recommendation for adoption of no-till or conservation tillage in soils of the temperate region, and of minimal disturbance and effective erosion control in soils of the tropics.     

植物修复对锰尾渣污染土壤特性的影响

采用盆栽法研究栽培美洲商陆和大豆进行植物修复后,锰尾渣污染土壤特性的变化。栽培美洲商陆和大豆可增加土壤的碱解氮、速效磷、速效钾和有机质。栽培植物后,土壤pH值变化不显著,但土壤磷酸酶、尿酶、蛋白酶、蔗糖酶、硝酸还原酶和脱氢酶的活性都高于对照。栽培植物可影响土壤锰和镉的形态分布,降低土壤锰和镉总含量,减少土壤水溶性锰和镉含量。在锰尾渣污染区域,混种美洲商陆与大豆进行植物修复,改良土壤特性更佳。     

Genetic characterization of a collection of chayote, <Emphasis Type="Italic">Sechium edule</Emphasis> (Jacq.) Swartz,in Costa Rica by using isozyme markers

We established protocols for the analysis of genetic diversity in chayote (Sechium edule) by using isozyme markers, thereby determining the level of genetic diversity present in 42 accessions of chayote from Costa Rica. We obtained clear and reproducible zymograms for eight enzyme staining systems: PGM, 6-PGD, PGI, IDH, MDH, SOD, SKD, and EST, and were able to score 14 putative loci. Eight of the 14 loci examined were polymorphic. We found 35 distinct multilocus genotypes among these accessions. Five of these multilocus genotypes were homozygous for all loci. In addition, our data also revealed that most of the multilocus genotypes (24) were heterozygous for only one of the eight loci, and the rest were heterozygous for two or three loci (9 and 4 accessions, respectively). Seven multilocus genotypes were found in two different accessions. Dice similarity coefficient was used to study the relationship between accessions. This analysis, based on the presence and absence of alleles, revealed that accessions collected in the same location seldom shared the same multilocus genotype. The value of isozyme polymorphisms as tools to continue studies on the characterization of chayote is discussed.     

乙酰辅酶A羧化酶(ACC)的结构与功能

乙酰辅酶A羧化酶(ACC)催化乙酰辅酶A形成丙二酸单酰辅酶A的羧化作用,是在脂肪酸合成和代谢中起重要作用的中间代谢物。ACC包括ACCα和ACCβ两种形式,被不同的基因编码。ACC(α265 kDa)主要在脂肪生成活跃的肝脏、脂肪组织和乳腺中表达。ACC(β275 kDa)主要在β-氧化作为主要能量来源的骨骼肌和心脏中表达。对ACC的结构特点和基本功能进行了探讨。     

生防木霉菌Tr9701的鉴定及其生物学特性

对从土壤中分离、筛选出的生防木霉菌进行分类鉴定和生物学特性测定。结果表明,生防木霉菌属于半知菌类、丛梗孢目、木霉菌属,为绿色木霉(Trichoderma viride)。该菌以小麦粉和豆粉浸出液培养基生长最适,在小麦粉和PDA培养基上孢子生成最快、产生孢子量多,分生孢子在1%葡萄糖溶液中萌发效果最好;20~30℃为其菌落生长和分生孢子形成的适宜温度;木霉菌菌落生长和孢子可以耐受45℃的高温,致死温度为55℃持续15 min;适宜pH为5~8;短时间紫外线照射不会对生防木霉菌的生长和孢子着生产生影响。     

贡柑黑腐病病原菌生物学特性研究

摘要：在贡柑黑腐病病原菌分离鉴定的基础上,对其病原菌的生物学特性进行研究。结果表明,该病原菌（Alternaria citri Ellis & Everhart）在PDA培养基上生长最佳。菌丝生长和分生孢子萌发的适宜温度分别为21~30 ℃和18~30 ℃,适宜pH值分别为5~12和4~7。供试的6种碳源中,葡萄糖和可溶性淀粉较利于菌丝生长,蔗糖较利于孢子萌发;供试的6种氮源中,牛肉膏较利于菌丝生长,酵母膏较利于孢子萌发。光照条件对病原菌产孢影响不大,完全光照与光暗交替12 h较利于菌丝生长和孢子萌发。分生孢子致死温度为51 ℃水浴10 min。     

生物质棕榈油的材料化研究

将生物质棕榈油在一定条件下与偶氮二乙丁腈（AIBN）、活性单体甲基丙烯酸缩水甘油酯（GMA）和甲基丙烯酸羟乙酯（HEMA）共同作用,转化为聚合物材料．对该聚合物材料的结构用红外光谱进行了表征,热行为用热重及差热分析进行了研究,结果表明,聚合物材料在180℃下稳定性良好．