新型控制设备在城市供水系统中的应用

我国是水资源贫乏国之一。淡水的缺乏将影响人民正常的生活和社会经济的发展，这就将社会经济发展的重要设施之一一城市供水系统的综合自动化建设提到了日程。为此．介绍了软启动器、变频器、无刷无环启动器的特点和技术演变过程，以及在城市供水系统中的应用。     

添加发酵剂对普洱茶发酵过程中温度及主要成分变化的影响

将筛选出的青霉、黑曲霉和根霉按1:1:1比例制得的发酵剂用于普洱茶发酵,添加量为1%,取得了较好的发酵效果。将发酵剂应用于生产中进行发酵验证,设发酵剂组和对照组2组。试验中首次对普洱茶发酵过程中的温度变化进行实时监控分析。发酵完成后,对2组茶进行了感官评审和主要成分分析,得出发酵剂组的各翻堆茶样在汤色、香气、滋味和叶底方面都较对照组好,且普洱茶的渥堆发酵成熟速度明显快于对照组;在温度变化方面,发酵剂组和对照组的茶坯中心温度基本维持在40～60℃之间,发酵剂组的温度高于对照组2℃左右;在主要成分变化方面,茶多酚、儿茶素、茶红素及水溶性总糖的含量是呈下降趋势的,而茶褐素、茶黄素经发酵后有明显的上升趋势,发酵剂组的变化曲线总是快于对照组。研究结果表明,本发酵剂用于普洱茶发酵过程中,可以提高普洱茶的品质,缩短发酵周期。     

起动机与蓄电池的合理使用

蓄电池与起动机是汽车上的重要部件,其使用容易引起人们的忽视。掌握合理的起动与使用方法,对延长蓄电池与起动机使用寿命、降低汽车使用成本、提高运输效益至关重要。介绍起动机和蓄电池的合理使用方法,为驾驶员正确操作和提高机车使用寿命提供技术指导。     

高铜、高锌日粮中铜、锌、铁最适添加量的探讨

用 690头杜长大三元杂交仔猪进行试验 试验结果表明 :满足仔猪日增重最高时日粮中的添加量为铜 2 50mg/kg ,锌 (氧化锌 ) 2 613mg/kg ,铁 2 15mg/kg ;满足耗料比最低时的添加量为铜 2 50mg/kg ,锌 (氧化锌 ) 2 655mg/kg ,铁 172mg/kg ;满足腹泻率最低时的添加量为铜 2 50mg/kg ,锌 (氧化锌 ) 2 717mg/kg ,铁 153mg/kg     

酸奶生产过程中的关键控制点研究

分析了酸奶生产过程中原料乳的质量、热处理、发酵剂活力、接种量、发酵温度与时间、冷却、贮藏等关键控制点对产品品质的影响。试验表明,全脂乳固体含量11.5%、高温瞬时灭菌(120℃3s)、嗜热链球菌和保加得亚乳酸杆菌发酵剂(发酵剂活力>0.7)、接种量为3%、发酵后快速冷却,可以有效控制酸奶品质。     

Soybean Growth Response to Low Rates of Nitrogen Applied at Planting in the Northern Great Plains

ABSTRACT

Cool and wet soils at the time of soybean [Glycine max (L.) Merrill] planting in the northern Great Plains may reduce early crop growth and retard nitrogen (N) fixation. Application of N as starter fertilizer may increase initial growth of soybean, but may also negatively impact N fixation when environmental conditions improve. The objective of this study was to evaluate the impact of low rates of N applied at planting on soybean N fixation and crop growth in the northern Great Plains. A field experiment (2000–2002) was established within a two-year corn [Zea mays (L.)] soybean rotation using a split-plot design with four replications. Whole plots were no-tillage (NT) and conventional tillage (CT) and the split plots were starter fertilizer (two sources × four rates) treatments. Nitrogen sources were either ammonium nitrate (AN) or urea (UR) each applied at 0, 8, 16, and 24 kg N ha^?1. Biomass in both 2000 and 2001 growing seasons increased significantly with increasing N rate at both growth stages (R1 and R7) and at the R1 stage in 2002. Ureide concentration and relative ureide decreased with increasing N rate at the R1 stage in all years, indicating a decrease in N fixation up to that point in crop development. This decrease in N fixation was not present at the R7 stage, but the significant increase in plant growth including yield was still present, indicating possibly that starter fertilizer can positively impact soybean production in the cool environmental conditions of the northern Great Plains. However, the positive impact on plant growth and yield is dependent on in-season environmental conditions and time of planting.     

Natural food and artificial,dry starter diets: effects on growth and survival in intensively reared European grayling

Four artificial, dry feeds and two diets consisting of natural, live food were evaluated for use as starter diets in the intensive rearing of European grayling (Thymallus thymallus). Long-term effects of the different diets were also studied. The investigation was divided into two parts: a 14 day starter period and the subsequent 115 days, during which the long-term effects were studied. Diets differed between the different treatment groups during the initial 2 weeks, whereafter all fish were offered a single diet. At the end of the starter period, significant differences in weight (p<0.001) were obtained between natural (control) feed groups and three of the artificial feed groups. The highest growth rate (9.6% day^–1), and length increase (9 mm) as well as the lowest mortality rate (6.0%) were obtained with one of the artificial diets. Growth rate, length increase and mortality of grayling in the other diet groups varied from 3.6 to 7.7% day^–1, 5 to 7 mm and 7.0 to 9.1%, respectively. The switchover to a different dry diet resulted in an increase in mean daily mortality for all groups previously fed a dry diet. For the fish previously fed live food the mortality rate remained about the same. Groups of fish growing slowly during one period seemed to compensate for their initially low growth by increasing their growth rates during the next period. The highest mean daily mortality for all groups during the experiment was observed during the period with the highest water temperature. It was concluded that European grayling can be intensively reared during the start-feeding phase on artificial as well as natural diets, and that artificial dry diets can be used exclusively throughout the first summer.     

Effect of macronutrient ratio of the pre‐starter diet on broiler performance and intermediary metabolism

The aim of this study was to investigate the influence of isoenergetic substitution between the three energy delivering macronutrients in pre‐starter diets on performance and intermediary nutrient metabolism in broiler chickens. From hatch until 5 days of age, 600 chicks, collected during peak of hatch, were fed one of the three experimental pre‐starter diets with isoenergetic (13 MJ metabolisable energy/kg) substitutions between fat (43 vs. 108 g/kg), protein (126 vs. 240 g/kg) and carbohydrates (391 vs. 510 g/kg). After 5 days, commercial grower and finisher diets were provided. Pre‐starter composition influenced body weight until slaughter age, although not statistically verifiable. Broilers fed the low protein (LP) pre‐starter had the lowest body weight in relation to chickens on the low carbohydrate or low fat pre‐starter diet. After hatch, chicks on the LP pre‐starter diet were able to use the residual yolk sac more rapidly to fulfil their protein requirement, which is reflected in small intestine and liver development. Also, plasma metabolite levels were influenced mostly by the LP pre‐starter, indicating that the main focus for the requirements of newly hatched chicks should be on proteins. Furthermore, optimal nutrition during the first day’s post‐hatch should take into account the contribution of the yolk.     

Lentil Response to Nitrogen Application and Rhizobia Inoculation

Lentils (Lens culinaris L.) are an important component of the dryland farming systems in the western USA. Optimum nitrogen (N) management can enhance yield and quality of lentils. We conducted a field (at two locations, one with previous history of lentil and the other one without lentil history) and a greenhouse study to evaluate response of lentil to the application of rhizobium inoculant and starter N (control, 22 kg N ha^?1 in the form of urea [U], 22 kg N ha^?1 in the form of slow-release or environmentally safe nitrogen [ESN], and 22 kg N ha^?1 U + 22 kg N ha^?1 ESN). In both, the field and the laboratory studies, lentil yield did not respond positively to the experimental treatments. Lentil average yield was 1216 and 1420 kg ha^?1 at the field condition. In this rain-fed system, lentil yield was mainly limited by moisture availability, and the application of an external N did not contribute to the yield enhancement. Both of these treatments, however, increased protein content. Compared to the control, the application of rhizobium plus U and ESN enhanced protein content by about 34% (from 23.1 to 30.9%). The application of U+ESN also considerably increased postharvest residual nitrate (NO₃)-N in the soil, which can be easily leached and creates environmental pollution. Briefly, the application of U+ESN increases lentil protein content, but more efforts are needed to optimize N management in lentils in order to reduce the environmental concerns in the shallow soil.     

鸡粪基质化生产有机肥的发酵剂筛选

为缩短鸡粪基质化生产有机肥的堆肥发酵周期,提高其产品质量,采用接种发酵剂并添加农作物有机附产物的方法研究不同菌种配伍的发酵剂(C_1、C_2、_3、C_4及C_5)对鸡粪堆肥发酵的影响。结果表明:C_3和C_4处理的各项指标均较好。其中,其发酵初始气温37℃,第2天达40℃以上,并保持高温15d以上,发酵的第18天含水量降至35%以下;pH呈下降—上升—稳定的趋势,总体稍有上升,但变化幅度不大(0~0.5);发酵有机肥对油菜种子的发芽及生长较好,其发芽率、芽长及根长分别为100%和97.5%,15.94mm和14.57mm,45.97mm和39.44mm,市售菌剂的发芽率、芽长及根长分别为95%、14.18mm、39.03mm。有机肥的有机质含量、氮磷钾总量及pH分别为86.62%和85.17%,8.85%和8.22%,7.5和8.0,均符合行业标准NY525—2012。2种处理对新鲜鸡粪的发酵均能在20d内完成,符合规模化有机肥生产企业的生产要求。