响应面法优化黑盖木层孔菌菌丝体液体发酵培养基研究

应用Plackett-Burman设计法对影响液体发酵黑盖木层孔菌菌丝体产量的培养基组分进行筛选,确定影响菌丝体产量的关键因素为玉米粉、麸皮和VB1。在此基础上,采用最陡爬坡试验结合Box-Behnken响应面法优化黑盖木层孔菌液体发酵培养基。结果表明:当培养基组分中玉米粉为65 g/L、麸皮为49.31 g/L、VB1为214.61μg/L时,菌丝体产量预测值为10.75 g/L,最佳条件下菌丝体产量可达11.16 g/L,预测值与验证值吻合得较好。     

基于离散元的包膜肥料Bonding模型参数标定

包膜肥料是在粒状水溶性肥料表面涂覆半透水性或不透水性物质,养分通过包膜的微孔、缝隙慢慢释放出来,节肥增效作用显著。包膜肥料的养分释放特性与包膜层材料、结构紧密相关,目前常用的排肥器在排施肥料过程中会对肥料颗粒造成不同程度的机械损伤,导致包膜层破坏。为设计适用于包膜肥料无损排施的排肥器,同时缩短研发周期,采用离散元软件中的Bonding模型建立肥料颗粒仿真模型。为提高仿真精度,需对Bonding模型进行参数标定。首先通过单轴压缩试验得到包膜肥料颗粒的实际极限破碎位移和极限破碎载荷,在离散元软件中以此为目标依次通过Placket-Burman试验、Steepest ascent试验和Box-Behnken试验确定最优的Bonding模型参数组合。最优条件下单轴压缩试验表明,极限破碎位移和极限破碎载荷与实际值的相对误差分别为0.222%、0.554%。借助外槽轮排肥器验证所得标定参数组合的可靠性,以肥料颗粒破碎率为指标,得到实际与仿真中肥料颗粒破碎率相对误差不大于11.40%,满足施肥机械设计参数优化需求,可为研究包膜肥料颗粒机械破碎机理、优化设计无损排施的新型排肥器提供参考。     

Designing crop technology for a future climate: An example using response surface methodology and the CERES-Wheat model

Future crop production will be adapted to climate change by implementing alternative management practices and developing new genotypes that are adapted to future climatic conditions. It is difficult to predict what new agronomic technologies will be necessary for crop production under future climatic conditions. The purpose of this work was to develop an approach useful in identifying crop technologies for future climatic conditions. As an example of the approach, we used response surface methodology (RSM) in connection with the CERES-Wheat model and the HADCM2 climate simulation model to identify optimal configurations of plant traits and management practices that maximize yield of winter wheat in high CO₂ environments. The simulations were conducted for three Nebraska locations differing in altitude and rainfall (Lincoln, Dickens and Alliance), which were considered representative of winter wheat growing areas in the central Great Plains. At all locations, the identified optimal winter wheat cultivar under high CO₂ conditions had a larger number of tillers, larger kernel size, fewer days to flower, grew faster and had more kernels m⁻² than the check cultivar under normal CO₂ conditions. In addition, optimal sowing dates were later and optimal plant densities were smaller than under normal conditions. We concluded that RSM used in conjunction with crop and climate simulation models was useful in understanding the complex relationship between wheat genotypes, climate and management practices.     

新疆天山北坡经济带滴灌棉田土壤质量演变趋势分析

对新疆天山北坡经济带滴灌棉田不同年限的连作耕地土壤质量演变趋势分析结果表明．研究区土壤肥力质量总体呈上升趋势。农业土壤的有机质含量先升后降,平均含量整体增加;全氮和速效磷含量呈S型上升趋势,局部地区有积累趋势;速效钾则成明显下降趋势。地区差异从时间跨度上看,土壤肥力的总体水平呈增加趋势,但在水平和变化上都存在明显的地区差异。     

Lipid content of Calanus finmarchicus during overwintering in the Faroe–Shetland Channel

Lipid class contents and composition of the copepodite stage CV and adult female Calanus finmarchicus were measured from the autumn to the spring along a transect crossing the Faroe–Shetland Channel. The data give a detailed vertical resolution of lipid content of C. fin-marchicus before, during and after the time of diapause. In the deep water, where C. finmarchicus was in diapause, the wax ester (WE) content did not change between the autumn and spring with the exception of that of females, which showed a significant decrease in lipid content by March. The concentrations of lipids were lower and more variable in both CV and females in surface waters over the sampling period. In March, the lipid concentration of both CV and females decreased significantly with decreasing depth. The triacylglycerol (TAG) content of both CV and females was high in October at all depths but had almost disappeared by December. The TAG was either utilized during this time period or converted to WE. TAG was most prominent in October and again in February in copepods in the upper water column. A simple diagnostic model is presented that estimates how C. finmarchicus allocates energy reserves from lipids into various metabolic functions. The cost of diapause, molting, gonad formation and ascending from depth is estimated based on the time series data. The model indicates that the major portion of the stored lipid goes into gonad formation, in physical ascent and in basic metabolism during ascent, whereas maintenance of diapause and molting is not expensive in terms of lipid utilization.     

响应面法优化乳双歧杆菌Z-1冷冻干燥保护剂配方

采用响应面法对乳双歧杆菌Z-1冷冻干燥保护剂配方进行优化。通过Plackett-Burman试验与最陡爬坡试验确定影响乳双歧杆菌Z-1冷冻干燥后活菌数的显著因素及最优响应值区间，再通过Box-Benhnken试验优化得到乳双歧杆菌Z-1冷冻干燥保护剂最佳配方。结果表明：海藻糖、蔗糖、L-半胱氨酸盐酸盐添加量是影响乳双歧杆菌Z-1冷冻干燥后活菌数的显著因素；经响应面试验设计建立活菌数和海藻糖、蔗糖、L-半胱氨酸盐酸盐添加量的回归模型，得到乳双歧杆菌Z-1冷冻干燥保护剂最佳配方为海藻糖添加量200.51 g/L、蔗糖添加量46.16 g/L、L-半胱氨酸盐酸盐添加量2.31 g/L，其他成分不变（脱脂乳粉添加量100 g/L、乳清蛋白粉20 g/L、甘油4 g/L、异抗坏血酸钠10 g/L、谷氨酸钠8 g/L）。     

响应面法优化富硒金针菇菌株发酵培养基的研究

金针菇[Flammulilna veluptipes(Curt.:Fr.)Sing]是一种高蛋白、低热量、富含多糖的营养保健食品,有益于儿童的智力发育[1]。金针菇所含的朴菇素具有显著的抗癌和降胆固醇的作用,可预防高血压和治疗消化道炎、肝炎等。通过金针菇深层液体发酵,可以开发各种保健饮料。在金针菇深     

Rate of acropetal transport of the xylem stream in phaseolus vulgaris

Hate of acropetal movement of the xylem stream was measured in the petioles, epicotyls, and hypocotyls of bean plants. Loss of water by intact, transpiring plants was first determined gravimetrically. Next, volume of the functional xylem in various sections of the stems was determined using radioisotope dilution techniques. Rate at which the xylem stream renewed itself to account for the overall water loss of the plant served as the basis for flow rate values.     

基因工程大肠杆菌发酵生产α-环糊精葡萄糖基转移酶的培养基优化

对基因工程大肠杆菌发酵生产α-环糊精葡萄糖基转移酶的培养基进行了优化,首先通过单因素试验,挑选出对菌株产酶有较大影响的因子及浓度范围,再通过两水平析因试验和最陡爬坡试验确定显著影响因子和浓度拐点,最后采用响应面分析法确定得到培养基成分的最佳配比为:甘油10.74g·L-1,酵母提取物51.85g·L-1,酵母蛋白胨10g·L-1,磷酸氢二钾22.82g·L-1,磷酸二氢钾2.85g·L-1。与原始培养基生产水平相比,采用优化培养基后,酶活提高了48.4%。     

坡口机工装夹具原理及特点

本夹具装置中加工链的旋转装置使得能对多块工件进行连续加工,其自带的单元夹具板也将工人从重复枯燥的手工定位送入以及取出中解放出来。在进行生产时工人只需在工件安装区域装入工件,工件会在工件脱落区域自行脱落。如此一来解决了“一人一机”的低效局面,一个工人可同时照看多台机器,在缩短了辅助时间的同时极大的提高了生产效率。