怀化市侗文化城入口区景观设计

风景区入口空间是风景区序列空间的起始,能够表现风景区的性质、内容与特征,起到缓冲与回味空间,解决交通、服务、管理、办公等景区配套的功能。通过对风景区入口空间组织原则的分析,以怀化市侗文化城入口空间的景观设计为例,分析了其景观设计中的限制因素,解析了侗文化城入口空间的景观设计理念和细部设施,将理论付诸实践之中,取得了较好的景观效果。     

我国农地产权法律制度存在的问题及对策研究

在对我国农地产权法律制度问题进行分析的基础上,建议通过农地产权股权化这一路径弥补农地产权制度的不足。     

“长株潭”城市圈在城市化进程中农村人口转移与农村土地制度变革研究

为加快＂长株潭＂城市圈的工业化和城市化进程,建设资源节约型和环境友好型的＂两型社会＂。通过总结全国土地改革先进城市的经验,分析了现行的土地制度所引发工农与城乡差距,农村土地承包,经营权的流转机制不完善,农村集体所有权主体虚置,产权内容残缺,家庭分散经营模式的不适应和政府职能缺失的矛盾;并结合自身的优势,提出城市化进程人...     

陶瓷复合膜分离工艺生产新生牛血清的研究

【目的】探索一次性过滤截留新生牛血清中细菌、霉菌、支原体等微生物及免疫球蛋白的工艺技术,为新生牛血清规模生产提供技术支撑。【方法】采用陶瓷复合膜分离生产新生牛血清,经细菌、支原体、牛病毒性腹泻病毒（BVDV）抗体、细菌内毒素等微生物及免疫球蛋白检测,并进行新生牛血清产品细胞培养试验。【结果】陶瓷复合膜能一次性成功截留新生牛血清中的细菌、支原体、细菌内毒素、BVDV抗体,过滤后细菌内毒素含量低于0.1EU/mL,免疫球蛋白去除率在97.00%以上;以其培养SP2/0细胞的细胞倍增时间、单克隆效率等指标接近于进口Hyclone胎血牛清水平。【结论】采用陶瓷复合膜分离工艺生产新生牛血清,实现了一次性有效过滤截留牛血清中细菌、霉菌、支原体等微生物及免疫球蛋白的目标,且能够满足细胞生长的营养需求,为大批量生产优质新生牛血清产品奠定了基础。     

2种马铃薯挖掘铲的对比分析

马铃薯挖掘机挖掘铲的结构直接影响着挖掘机的入土性能、碎土性能、动力性及刚度,在含水率约为12.6%的黄绵土中对三角形平面铲和栅条式挖掘铲的入土性能和碎土性能等方面进行对比分析.结果表明:栅条式挖掘铲挖掘效果优于三角形平面铲,动力性能好;且栅条式挖掘铲的栅条对土壤有拱碎作用,能够减少进入分离装置的土壤量,有利于土薯分离.     

应用响应面法优化金丝桃素的纯化工艺

在单因素试验的基础上,根据中心组合试验设计原理,选择上柱液中金丝桃素的浓度、洗脱液中乙醇的浓度和洗脱液用量为考察因素,以产物中金丝桃素含量为响应值,采用3因素5水平的响应面分析法对NKA-9型大孔树脂分离纯化贯叶连翘中金丝桃素的工艺条件及参数进行优化.结果表明:金丝桃素的最佳纯化工艺条件为上柱液中金丝桃素的浓度37.6...     

凝胶过滤层析参数对EV71病毒粗提液分离效果的影响

通过凝胶过滤层析达到分离纯化EV71肠道病毒粗提液,以提高EV71的纯度.选用不同的洗脱流速、不同样品上样量、不同的缓冲溶液的pH值和不同盐浓度对EV71肠道病毒粗提液进行连续洗脱.结果表明,凝胶过滤层析的洗脱流速、样品上样量、缓冲溶液的pH值和盐浓度对EV71病毒均能不同程度地影响EV71病毒粗提液的分离效果.在试验...     

小型马铃薯挖掘机的设计与试验研究

针对现有马铃薯挖掘机存在的问题,设计了一种与农用拖拉机配套的小型马铃薯挖掘机。田间试验表明,性能达到并优于技术规范要求。     

从小桐子油提取分离醇溶性二萜的工艺研究

采用甲醇萃取的方法提取分离小桐子油中醇溶性二萜和脂肪酸;在确定萃取温度和搅拌速率的基础上,探讨了液液比(甲醇/小桐子油)、搅拌时间和提取次数对二萜提取率的影响,分析了冷冻温度和时间与脂肪酸分离的关系;并建立了紫外分光光度法测定小桐子油中二萜的含量的方法。结果表明:当萃取温度30℃,搅拌速率120 r/min,搅拌时间20 min,萃取次数为4次,4次液液比(甲醇/小桐子油)依次为2.5、2.0、1.5和1.0时,萃取效率最佳。     

A quantitative size–density separation method to recover and characterise decomposing crop residues added to soil

Plant residues placed in soil in mesh bags do not mimic realistic decomposition conditions. Alternative techniques, e.g. combined particle size and density methods, have been proposed to monitor in situ decomposition of plant residues, but are not appropriately evaluated for their ability to quantitatively recover and characterise decomposing residues of a range of sizes mixed with soil over long incubation times. For this study, we used canola residues of three different starting sizes (<1, 5–7 and 20–25 mm) mixed in a soil and incubated for 6 months. The modified method presented here relied on initial size separation of soil and organic particles into fractions of sizes <106 and >106-μm by wet sieving, and then by repeated floatation and decantation, using water as a density agent, to recover and characterise decomposing canola residues from a mixture of >106-μm mineral plus organic materials into >106-to-500 and >500-μm fractions. On day 0, across the three residue-size treatments, the >500-μm fraction recovered 93–96% of canola residue-C, with water-soluble residue-C loss during the recovery process quantified as representing further 4–5%. The rate of loss of residue-C in the >500-μm fraction was the largest, matching well the cumulative respiration loss of residue-C. The recovery of canola residue-C in the >500-μm fraction, determined as percent of cumulative CO₂–C respired of added C, decreased to 72–76% by the end of incubation, likely due to progressive generation of finer-sized residues and microbial/faunal metabolites. The increase of N in the >500-μm fraction accounted for ca. 40% of total soil N immobilised in the residue-amended soil. The extent and patterns of changes in C, N and S contents, and C-to-N and C-to-S ratios of separated fractions were similar among all the residue treatments during decomposition, except for the ground-residue treatment. The combined size and density separation procedure can be used to study decomposition in situ of soil-mixed plant residues of different sizes that are usually found in agro-ecosystems.