土地利用地域分区方法研究——以桂林市为例

本文采用遥感解译地域分类和聚类分析归类方法，对桂林市土地利用地域分区进行了研究。结果表明：１）地貌是明显区域，两种方法分区结果基本一致；２）区内地貌类型基本一致区域，应以聚类分析地域归类为主；３）地貌类型过渡区域，应采取遥感解译地域分类和聚类分析地域归类相结合方法，并考虑土地利用本来发展方向等。     

Harmonization of collaborative study protocols

The 2 major protocols for the design, conduct, and interpretation of collaborative analytical studies--those from AOAC and the International Organization for Standardization--are already fairly well harmonized. The statistical models are identical and the outlier tests are essentially the same. The major differences are in symbols and terminology and in the specification of the minimum number of laboratories and replicates.     

Flocculation study on spiral flocculator

Traditionally, the Jar Test has been used to assess the suitability of flocculation treatment for a given raw water. Unfortunately, the Jar Test suffers from a number of disadvantages. The new method of assessment of flocculation, Spiral Flocculator, has been claimed to be a better method than the Jar Test apparatus and a good method for continuous assessment of flocculation. This study compares the performance of Spiral Flocculator and Jar Test, and mathematical modeling of the Spiral Flocculator performance. The experiments conducted reveal that the Spiral Flocculator has a better effective energy dissipation compared to that of Jar Test. However, the size of flocs in Spiral Flocculator seems to be overestimated relative to the real flocculator and Jar Test.     

原花色素研究进展

原花色素是葡萄中一类重要的多酚类次生代谢化合物,是影响葡萄酒品质的重要因子之一.该文从原花色素的结构、性质、生理功能、葡萄果实中的分布及存在形式等几个方面对近年来研究成果进行了综述,并讨论了葡萄酒中原花色素的来源、对葡萄酒品质的影响及提高葡萄酒中原花色素含量的工艺措施,指出了存在的问题及今后的研究方向.     

FTIR study of glyphosate-copper complexes

Complexes of the herbicide glyphosate (GPS) and the heavy metal Cu were studied by infrared spectroscopy under controlled pH, in order to know the mechanisms involved in the formation of these complexes. In CuGPS(-), the IR spectrum shows participation of the carboxylate and phosphonic moieties of the GPS molecule. The formation of the complex produces a lower symmetry in the phosphonate group because of loss of the resonance situation of PO(3)(2)(-) groups, with a subsequent split of their absorption bands. Carboxylate groups are participating by forming unidentate complexes. No conclusion is reached about the involvement of the amino group, but previous EPR findings indicate coordination of GPS to Cu via nitrogen. Consequently, glyphosate in this complex functions with a tridentate character by forming two chelate rings. A study of the CuGPSH species was not possible due to overlapping of its absorption bands with those of free GPS species.     

鸡蛋壳生物力学特性分析及试验研究

本文应用弹性薄壳力学理论，推导了鸡蛋的曲率半径表达式及鸡蛋在一定均布载荷下的应力公式，并经试验验证了其结果的正确性。结果表明：鸡蛋在长径方向的抗压载荷比短径方向大；中间部位受压破裂时，沿纬线方向产生的应力比经线方向大；鸡蛋在短轴方向受压破损时，裂纹多沿长轴方向产生，约占总数的52.5%，理论分析与试验结果一致。该力学特性研究可为鸡蛋的包装、运输及相关装备的制作提供一定的理论指导。     

工业木质素的热裂解试验研究

本文研究了木薯水解剩余木质素在N2氛围下的TG和DTG曲线,以及在不同升温速率下热裂解产物的组成随温度的变化情况。试验结果表明,在290~430℃之间热裂解速率最快;在400~800℃之间时,焦炭产量随着温度的升高而降低,焦油产量首先会随着温度升高而增加,在达到一个最大值后,随着温度的进一步升高,部分挥发分的二次热解会使焦油产量降低,气体产量随着温度的升高而增加,H2、CO、CH4和CO2等组分也随着温度的升高而有相应的变化;快速热解在600℃以下有利于焦油和焦炭的生成,在600℃以上有利于气体的生成。通过GC—M S分析发现焦油中的组分主要是苯酚类化合物。     

Granitic weathering: a Brazilian study

Chemical and mineral studies were carried out on weathered materials from six profiles developed on granites located in different areas of Brazil. Quartz and K-feldspar are the most abundant minerals overall. Kaolinite is the most common secondary mineral and is principally a feldspar weathering product. Mica breakdown is associated with smectite formation in semi-arid regions. In more humid regions mica weathering products include interlayered mica-vermiculite, vermiculite and kaolinite. Changes in the concentrations of Si, Al and K reflect the weathering behaviour of quartz, kaolinite, K-feldspar respectively, although K mobilities sometimes appear to be governed by processes related to the formation of secondary minerals. Ca and Mg are the first elements to exhibit depletion and their removal rates are very fast relative to K. P is also among the most mobile elements. Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba and Pb concentrations were measured. The first row transition metals are the most depleted. Rb and Sr are retained relative to Na, Mg, and Ca, and Ba accumulates as weathering proceeds. Y, Zr, Nb and Pb concentrations show little variation. The conclusion is that the factors controlling deep leaching are complex and the common notion that weathering rates are higher at lower latitudes should be reassessed.     

作物多尺度力学初探

作物力学性能广泛应用于作物抗倒伏性、机器-作物-土壤互作系统和作物栽培等领域的研究,为培育抗倒伏品种、提高机器作业质量和改进栽培措施提供理论支持。作物的力学性能与其形态结构、解剖学特征、化合物组分等有密切关系。该研究在梳理作物力学性能研究的基础上,将作物多尺度力学概括为以作物为研究对象,分别以细胞壁层、细胞壁、细胞、组织和器官为基本元件,依次建立细胞壁、细胞、组织、器官和植株的几何结构与力学模型,并解析其力学性能的科学。进一步对细胞壁结构力学、细胞结构力学、组织结构力学、器官结构力学和植株结构力学的研究内容进行了归纳总结。该研究明确提出作物多尺度力学的概念、系统归纳其研究内容和方法,有利于促进作物多尺度力学理论的形成、数据库的建立和分析软件的开发。     

Electrochemical study of the Maillard reaction

Electrochemical properties of beta-alanine/carbohydrate Maillard reaction products were measured using a combination platinum/Ag-AgCl (Cl(-)) redox electrode. Changes toward more negative voltages were observed, which were consistent with reductone formation during the course of the Maillard reaction. Using voltage change as a guide, the propensity for reductone formation among various sugars was ribose > xylose approximately arabinose > glucose approximately rhamnose approximately mannose approximately lactose > fructose. Similar electrochemical behavior indicative of reductone formation was observed in the decomposition products of a model Amadori compound, N-(1-deoxyfructos-1-yl)piperidine (1).     

工厂化农业技术标准研究浅析

农产品工厂化生产是现代农业的重要标志,工厂化农业发展的关键是现代科学技术.通过标准化研究,明确工厂化农业领域内技术标准化工作的范围、作用、原理,指导工厂化农业技术标准的研究和制定,加快农业生产标准化,促进农业科技成果转化,提高农业生产力水平.     

Interlaboratory study of blood selenium determinations

Fifty-one laboratories from 14 countries participated in a survey on the determination of selenium (Se) in 8 bovine blood samples with Se concentrations ranging from 0.2 mumol/L (0.016 microgram/mL) to 14 mumol/L (1.1 micrograms/mL). The methods used (and the percentage of participants using each method) were fluorometry (61), hydride-generation atomic absorption spectrophotometry (AAS) (23), graphite-furnace AAS (6), gas chromatography (4), neutron activation analysis (4), and X-ray fluorometry (2). There was little difference in the mean Se results obtained by fluorometry or hydride-generation AAS (P greater than 0.05). Mean intralaboratory coefficients of variation (CVs) from known replicates ranged from 4 to 14% for all samples. Interlaboratory CVs were related to blood Se concentration and increased to 55% at Se levels below 0.4 mumol/L (0.032 microgram/mL). Laboratories that used quality control (QC) schemes had lower interlaboratory CVs than those that did not, but the advantage began to diminish at blood Se concentration below 0.4 mumol/L (0.032 microgram/mL). The high interlaboratory CVs, coupled with the false assurance from the low intralaboratory CVs and the ineffectiveness of the QC schemes at blood Se concentrations below 0.4 mumol/L (0.032 microgram/mL), are of concern in diagnosis of marginal Se deficiency in livestock where the concentrations of interest are in the range 0.15-0.5 mumol/L (0.012-0.039 microgram/mL).     

滑道分钵轮式栽植器的试验研究

对滑道分钵轮式栽植器的结构、工作过程、钵体在滑道不同部位的运动状态和受力情况进行了分析，并对该栽植器的工作稳定性和立苗率进行了正交和单因素的试验分析。影响栽植器立苗率的因素顺序是钵体含水率，钵体侧面形状和滑道倾角。影响栽植器立苗率的主次因素，有覆盖物时是：滑道尾部的离地高度、机具前进速度、滑道倾角；无覆盖物时是：滑道尾部的离地高度、滑道倾角、机具前进速度。找出了栽植器工作稳定性的影响因素及其最佳值和对立苗率影响的因素及其最佳值。     

兔精液冷冻保存的初步研究

以家兔为试验动物,从精液解冻后的精子活率和复苏率2个指标,分别对3种稀释液(1:T ris0.25 m o l/L 蔗糖0.1 m o l/L 柠檬酸钠83 mm o l/L 卵黄10% 二甲基亚砜(DM SO)15%;2:配方1 葡萄糖0.47 mm o l/L;3:T ris 0.29 m o l/L 葡萄糖0.71 mm o l/L 柠檬酸钠67 mm o l/L 卵黄20% 甘油4%)、两种抗冻剂(甘油4%、DM SO 15%)、4°C下平衡时间(30、60、120、180 m in)三个方面进行了比较试验。公兔采精用假阴道法,采精后立即检查精子活率,达0.60以上的供试验用。结果表明:(1)3种稀释液中,用稀释液2稀释的精液,精子解冻后活率和复苏率显著高于稀释液1和稀释液3(精子活率:0.153 vs 0.103、0.109;复苏率:0.205 vs 0.137、0.147,P<0.01),而稀释液1和稀释液3之间差异不显著(P>0.05);(2)在稀释液2中,分别用4%甘油和15%DM SO作防冻剂,两者的精子解冻后活率之间(0.193 vs 0.261,P<0.01),复苏率之间(0.250 vs 0.340,P<0.01)差异极显著;(3)在4°C下平衡30、60、120、180 m in,结果发现,在30~60 m in之间,解冻后精子活率之间(0.261 vs 0.249),复苏率之间(0.340 vs 0.325)差异均不显著(P>0.05),但是随着平衡时间(120~180 m in)的增加,精子活率明显降低,精子几乎死亡。结论:采用稀释液2的配方,在4°C下平衡30~60 m in,可获得较好的兔精液冷冻保存效果。     

Quantitative structure-activity relationship study of bitter peptides

A database consisting of 224 di- to tetradecapeptides and five amino acids was compiled to study quantitative structure-activity relationships of bitter peptides. Partial least-squares regression-1 analysis was conducted using the amino acid three z-scores and/or three parameters (total hydrophobicity, residue number, and log mass values) as X-variables and bitterness values (log 1/T where T is the bitterness threshold) as Y-variables. Using the three parameters only, significant models (p < 0.001) were obtained describing the entire data set as well as data subsets, except that comprised only of octa- to tetradecapeptides. For data sets comprising different peptide lengths, the models were improved by including the three z-scores at the N-terminal and C-terminal positions. Correlation coefficients for bitterness prediction of 48 dipeptides and 12 pentapeptides were 0.75 (RMSEP = 0.53) and 0.90 (RMSEP = 0.48), respectively. Bulky hydrophobic amino acids at the C terminus and bulky basic amino acids at the N terminus were highly correlated to bitterness.     

草地农业效益研究--以黑麦草-水稻草田轮作为例

根据１９９２￣１９９７年桂林地区草地农业观测和研究资料,针对桂林地区农业和畜牧业及其开发利用的现状,研究了建立集约型草地农业的战略意义及技术上的可行性与经济上的高效性。草地农业在生产大量优质青饲料的同时,还起绿肥改土的作用,实现了牧草生产与动物生产相结合,草地与农田相结合,促进了农业生态系统形成草多－畜多－肥多－粮多的良性循性,达到了经济效益、生产效益和社会效益的同步增长。