电超滤浸提土壤养分的研究 Ⅰ.石灰性土壤的电超滤特性

石灰性土壤的电超滤(EUF)特性主要是浸提时因需控制电流而必须大大降低电压。在一定范围内,降压程度与土壤 CaCO_3%有密切关系。控流限额愈低,电压需成比例地下降,但土壤EUF-值减小不多。电流控制在一定值时,离子的解吸总量亦为定值。控流主要控制了各石灰性土壤解吸/溶解份额特大的 Ca+Mg 量近于定值,对于含量小的其他养分离子则并无多大影响,仍可区辨各土壤间的差别。通过冬小麦盆栽试验和有关化学测试法等方面的相关研究,表明采用国际通用的5g 土样和控电流方法测定 EUF-K 和-P 等有效养分,对于石灰性土壤也是可行的,但其EUF-(Ca+Mg)值则毫无植物营养有效性的意义。土壤 EUF 值只是一种指数,并非真正的解吸离子量。石灰性土壤 EUF-K 值因浸提时降压控流而略低,80℃时5min 内解吸的钾不一定是非交换性钾。由于 Ca-P 和 CaCO_3在高温高电压时浸出较多,故石灰性土壤 EUF-P 和-(Ca+Mg)的80℃值/20℃值之比,与酸性土壤或非石灰性土壤相比要大得多。     

古籍咨询工作中的新视角

本文讨论古籍咨询的服务创新问题,提出了内容咨询这一新概念。认为根据个人自身条件,有些咨询人员不妨可以对古籍的内容进行研究,这有利于与读者进行深入的交流,可以提高咨询水平的深度。     

农地租赁均衡价格影响因素分析

在一定的经济技术条件下,农地资源的合理配置和有效利用,取决于与之相关的一系列农地制度实施机制.文章基于产权理论、地租理论、土地供给与需求理论,以农地租赁均衡价格为切入点,对农地租赁的利益来源、均衡价格形成与演变影响因素进行了分析与探讨.结果认为,影响农地租赁均衡价格的因素主要是市场机制、政府机制以及习俗元制度.     

从矿难报道看转型期媒体的社会功能——以《南方周末》的矿难报道为例

处于社会转型期的中国，媒体有其特殊性：多元化的社会转型需要媒体发挥较为多元化的社会功能。一方面要继续保持党和政府的喉舌功能，另一方面叉要通过舆论监督来建立媒介信任，从而达到建立社会公信力，抢占市场的目的。笔者以《南方周末》的矿难事故报道为对象，分析目前中国媒体所担负的具体社会功能。     

非洲黑鸵鸟人工饲养条件下繁殖性能的观察

14只2岁非洲黑鸵鸟按公母比例1:2～3分成4个繁殖组合,对产蛋、受精、孵化情况进行观察分析。结果显示,每只母鸵鸟年平均产蛋量为55.2枚,最高约为73枚,最低为39枚。4个组合鸟群之间种蛋的受精率存在显著的差异P<0.01,I组的受精率最高,为59.6%;IV组的受精率最低,仅8.9%。各组的受精率、孵化率差异不显著P>0.05,平均受精蛋孵化率达到92.6%。本次受精率较低的原因为公鸟年龄小,没有完全达到性成熟。     

Particle Size Distribution in Two Lipid Emulsions Used for the Enrichment of Artemia nauplii as a Function of Their Preparation Method and Storage Time

The present study examined the distribution of particle sizes in two experimental standardized lipid emulsions (distributed by ICES, International Council for the Exploration of the Sea) as a function of the preparation method (hand shaking or ultrasonic blending) and as a function of storage time. A 24-h enrichment trial compared the incorporated HUFA levels in the nauplii of Artemia franciscana .
The emulsion droplets in the 50% HUFA emulsion (ICES 50, ethyl ester based) were much smaller than in the 30% HUFA emulsion (ICES 30, triacylglycerol-based) in which 90% of the droplets had a diameter below 12.3 μm as compared to 1.3 pn in ICES 50. The blending method highly affected particle sizes. High-shear blending instead of the classical hand shaking of the emulsion of both ICES 30 and 50 reduced the mean particle size from 5.06 to 1.07 μm and from 0.38 to 0.11 μm, respectively. The particle size distributions remained stable during the 1-wk storage, suggesting the absence of agglomeration or bacterial development. The fatty acid composition of 24-h enriched Artemia reflected differences in the HUFA profile of the emulsions, but was independent of observed differences in the size of the particles.     

Organic substance metabolism during seed germination ofPinus bungeana

The metabolism of fats, proteins and carbohydrates and change of enzyme of seeds ofpinus bungeana during the germination were conducted by the methods of gas-liquid chromatography, flow injection, colorimetric analysis of spectrophotometer, to provide theoretical basis for seeds dormancy, germination and storage of seeds of forest tree. The results indicate that (1) carbohydrates were first utilized during germination of seed ofpinus bungeana; (2) stored substances in seeds began to decompose quickly after radicale broke through seed coats; (3) the activity of enzymes in the seeds does not always coincides with the increase or decrease in quantity of its responsible substance during germination of the seed. Changes in stored substance relate to metabalism of other metabolism of other materials and the use of hydrolysates.     

Acute infection of encephalomyocarditis (EMC) virus in Syrian hamsters.

One-month-old Syrian hamsters of the APA and Std: golden strains were inoculated intraperitoneally with 10(5) PFU/head of the D variant of encephalomyocarditis (EMC) virus and examined virologically and pathologically up to 7 days after inoculation. APA hamsters developed apparent hyperglycemia due to pancreatic islet cell damage while Std:golden hamsters did not. Hamsters of both strains showed clear histopathologic changes in the testis with prominent viral replication as well as in the brain, heart and exocrine pancreas. The susceptibility to EMC virus-infection was higher in males than in females and in APA than in Std: golden hamsters.     

国产MJ3210小型木工跑车带锯机锯解正交试验分析

采用正交试验设计法，对国产MJ3210小型木工跑车带锯机的锯解质量进行研究。通过实测马尾松锯材尺寸偏差、表面粗糙度等参数，得到其最佳的进料速度、锯解厚度和锯卡高度的组合方案。结果表明，该设备具有结构简单、出材率高、锯解精度高、质量好、成本低和生产效率高等优点。     

哈达门森林公园的旅游气候资源

地处阴山山系中段大青山脉林区的哈园，其气候区划为我国中温带亚干旱气候类型。就整体而言，四季分明，内陆气候特征强烈；但因巨大阴山山地效应，年降雨量超过４５０ｍｍ，植被繁茂，形成多种多样的小气候环境，以高山环境、森林环境及峡谷环境为代表，它们冷暖干湿分异形大。气候的多样性，可满足旅游者的不同要求，产生了非凡吸引力，为哈园开发建设的宝贵自然资源之一。