小型家用电器控制电路的设计

从全新的角度阐述了一般家用电器控制电路各个模块的设计方法,力求在实现产品功能,保证产品质量的同时,尽量压缩设计成本,提高产品质量和抗干扰性能,为小型家电企业走技术型、节约型、环保型的发展路线提供良好的技术支持。     

Maximizing profit on New England organic dairy farms: an economic comparison of 4 total mixed rations for organic Holsteins and Jerseys

The objective of these experiments was to compare 4 total mixed rations fed to USDA-certified organic dairy cows in New England. Forty-eight Jersey cows from the University of New Hampshire (UNH) and 64 Holstein cows from the University of Maine (UMaine) were assigned to a 2 × 2 factorial arrangement of treatments testing the main effects of corn silage versus grass silage as the forage base and commodity concentrates versus a complete pelleted concentrate mixture. Treatment diets were fed as a total mixed ration for 8 wk during the winter and spring months of 2007, 2008, and 2009. Milk yield, component, and quality data were recorded and used to calculate the value of the milk produced for each cow. The dry matter intake (DMI) was recorded and used to calculate the average cost per cow per day of each diet. Income over feed costs were calculated for each diet using milk value and feed cost data. Feed cost and income over feed cost data were resampled using bootstrap methodology to examine potential patterns. Milk yield, milk fat and true protein concentrations, and SCC were similar among treatments. Cows at UNH fed corn silage tended to have higher DMI and lower milk urea nitrogen than did cows fed grass silage, whereas cows fed pellets had higher DMI than cows fed commodities. Cows at UNH fed commodities tended to have higher body condition scores than those fed pellets. Cows at UMaine fed commodities tended to have higher DMI than did cows fed pellets, and cows fed corn silage had lower milk urea nitrogen than did cows fed grass silage. Body weights and body condition scores were not different for cows at UMaine. Feed costs were significantly higher for corn silage diets and diets at UNH containing pellets, but not at UMaine. The calculated value of the milk and income over feed costs did not differ among treatments at either university. Bootstrap replications indicated that the corn silage with commodities diet generally had the highest feed cost at both UNH and UMaine, whereas grass silage diets containing commodities generally had the lowest cost. In contrast, the grass silage with commodities diets had the highest income over feed cost in the majority of the replications at both UNH and UMaine replications, whereas the corn silage with commodities diets had the lowest rank. Similar results were observed when forage prices were increased or decreased by 5, 10, and 25% above or below the actual feed price. Feeding a grass silage-based diet supplemented with commodity concentrates may have an economic advantage for dairy producers in New England operating under an organic system of production.     

基于模糊神经网络的建筑工程造价估计方法

提出了建筑工程造价估计的模糊神经网络方法,给和该方法进行建筑工程造 价估计的基本原理,网络模型及估价方法,计算实例表明,应用模糊神经网络估计工程造 价具有方便、准确的特点。     

Studies on the response of ‘Tifblue’ and ‘Woodard’ rabbiteye blueberries to fertilizers

A field study was conducted to investigate the effects of three fertilizer placement methods and 11 fertilizer formulations on plant survival, economics of replanting, yield, and fruit size of two rabbiteye blueberry (Vaccinium ashei Reade) cultivars Tifblue and Woodard. Fertilizer rates were either mixed with the soil under plants (before planting), sidedressed, or half-rate was placed under plants with the other half sidedressed. Fertilizers at planting caused a total of 34% Woodard and 12% Tifblue plants to die as compared to 6% for Woodard and none for Tifblue when no fertilizer was applied. Fertilizer formulas 2-1-1 and 5-10-10 oxide ratios placed under Woodard plants caused 100% mortality whereas Tifblue fertilized with oxide ratios 2-2-2 and 5-10-10 under plants reached the maximum 50% mortality. Splitting fertilizer placement under the side of the plants resulted in less Woodard plant mortality (30%) than placing all the fertilizer under plants (54%). However, plant mortality for the side/under group was not different than sidedressing all fertilizer (23%). A planted hectare in this experiment consisted of 1852 Tifblue and 926 Woodard plants, providing one Woodard plant to pollinate two Tifblue plants. Based on the results obtained, the 5-10-10 fertilizer placed under plants would be expected to cause half the Tifblue (926 plants) and all the Woodard (926 plants) to be replanted. Plant costs alone was estimated to be $2315 with additional replanting costs of $93 for Tifblue and much higher for Woodard. Sidedressing 5-10-10 fertilizer eight weeks after planting would have prevented plant mortality. Placement of various fertilizers under Woodard or Tifblue plants resulted in a significant increase in plant mortality as compared to side placement of fertilizers. Yield loss due to plant mortality increased linearly with the N level of the fertilizers (ranging from 0 to 2) for both cultivars. Woodard fruit size was not affected by fertilizer placement but placing fertilizers under Tifblue plants produced smaller yields with larger fruit than sidedressed plants. Blueberry plants in a virgin acidic soil may experience no reduction in yield if fertilization is completely eliminated.     

Vorkalkulation chemischer Anlagen

The economic analysis of processes allows a market orientation and prioritization of development projects. First of all, a preliminary costing takes place by estimating the investment costs. Basis for calculation is a complete process flow diagram with mass and energy balances for a layout of the process steps, performed in the standard material AISI 316Ti. Costs of other materials can be calculated with factors from a table, that of the other sizes and capacities by degression exponents. The preliminary costing is exemplified. The investment is the basis for the subsequent calculation of production costs.