关于求解病态方程组的残量迭代算法

本文在分析目前求解病态方程组各种算法的基础上,给出了求解病态方程组的残量迭代算法,并通过上机计算验证效果较好.     

Study on properties of residue-residue contacts in protein

INTRODUCTION Recognition of protein folding from aminoacid sequence is a challenging task. The structureand stability of proteins from different fold aremainly dictated by inter-residue interactions. In-formation on the distribution of contacts shown by20 amino acid residues can be used to predict thefolding type of each protein (Chan and Dill, 1998;Zhang and Kim, 2000; Gromiha, 2001; Gromihaand Selvaraj, 1999; Miyazawa and Jernigan, 1985;1996; Bahar et al., 1997; McDonald and …     

固体乙醇合成方法的研究

详细讨论了影响固体乙醇合成的各种主要因素,确定了最佳工艺条件。酒精∶水∶硬脂酸∶硅酸钠∶氢氧化钠的最佳配比为102∶15∶2.5∶0.75∶0.4,最佳反应温度为70℃。     

Laboratory simulated dissipation of metsulfuron methyl and chlorimuron ethyl in soils and their residual fate in rice, wheat and soybean at harvest

Two sulfonylurea herbicides, metsulfuron methyl （Ally 20 WP） and chlorimuron ethyl （Classic 25 WP） were evaluated for their dissipation bchaviour in alluvial, coastal saline and laterite soils under laboratory incubated condition at 60% water holding capacity of soils and 30 ℃ temperature was maintained. In field study herbicides were applied twice for the control of grasses, annual and perennials broad leaves weeds and sedges in rice, wheat and soybean to find out the residual fate of both the herbicides on different matrices of respective crops after harvest. Extraction and clean up methodologies for the herbicides were standardized and subsequently analyzed by HPLC. The study revealed that the half-lives of metsulfuron methyl and chlorimuron ethyl ranged from 10.75 to 13.94 d irrespective of soils and doses applied. Field trials with rice, wheat and soybean also revealed that these two herbicides could safely be recommended for application as no residues were detected in the harvest samples.     

有机絮凝剂对渣土废泥浆脱水效果影响

针对地铁盾构出来的渣土废泥浆污染环境,不便施工的现状,本文研究了有机絮凝剂(阴离子型聚丙烯酰胺、阳离子型聚丙烯酰胺以及两者复掺)对不同含水率下的渣土废泥浆絮体含水率、上清液浊度以及絮体大小等指标的影响。研究结果表明:不同种类的有机絮凝剂在不同掺量下均能改善渣土废弃浆脱水效果,并且针对不同含水率的废泥浆存在着最佳掺量不同;随着渣土废泥浆含水率的降低,有机絮凝剂的最佳掺量均逐渐增加;采用单掺阳离子型聚丙烯酰胺絮凝剂可明显提高渣土废泥浆的脱水效果。     

从肝素渣中提取小肽的工艺研究

本试验以肝素渣为原料,采用酶解法,按L9(34)正交试验设计,确定了生产含肽肝素渣水解物的酶解工艺。结果表明,处理8的有效成分含量最高,其肽蛋白含量为41.92%,其中2-6肽和2-3肽的含量分别为12.64%和7.56%。     

Persistence of gentamicin residues in milk after the intramammary treatment of lactating cows for mastitis

This study was designed to investigate persistence of gentamicin residues in milk after the intramammary treatment of lactating cows for mastitis. Milk samples were collected at a 1-d interval after the last administration from 34 individual cows that had received intramammary infusions of gentamicin. The doses and treatment times evaluated in this study represented those that have been applied by veterinarians in practice. The tetrazolium chloride assay was used to determine whether there were sig-nificant residues of the antibiotic in the samples. Persistence of detectable drug residues in milk from 33 cows (28 cows, <6 infusions at≤0.7 g gentamicin; and 5 cows, 2 infusions at 0.8 g gentamicin) did not exceed 5 d; but 1 cow (5 infusions at 0.8 g gentamicin) had detectable residues in its milk for 9 d. Our results suggest that a 5-d milk withdrawal period might be insufficient to secure the clearance of the contamination of gentamicin, because treatment times and dosages contribute to the antibiotic clearance. A larger scale of samples are needed for further investigations.     

Contribution of leaf growth on the disappearance of fungicides used on tea under south Indian agroclimatic conditions

The sprayed chemicals on tea leaves disappear over a period of time by the influence of rainfall elution, evaporation,growth dilution, and photodegradation. Influence of plant growth on the four fungicides (hexaconazole, propiconazole, tridemorph,and c) was studied to know the constructive loss of fungicides. The study shows that residues of fungicides sprayed on tea shoots got diluted by the growing process. The expansion of a leaf took 8 to 11 d and more than 50% of the fungicide residues were cleaned out during this leaf expansion period. Under south Indian agroclimatic condition, the fungicides are sprayed at an interval of 10 d, so it is safe that the tea is harvested on the 10th day of the application of fungicides.     

素数在域 上素理想分解

Let F = Q( ln√u), l an odd prime number. In this paper, we give prime ideal decompositions of odd prime numbers p over the integral ring OF .     

A kinetic approach to evaluate salinity effects on carbon mineralization in a plant residue-amended soil

The interaction of salinity stress and plant residue quality on C mineralization kinetics in soil is not well understood. A laboratory experiment was conducted to study the effects of salinity stress on C mineralization kinetics in a soil amended with alfalfa, wheat and corn residues. A factorial combination of two salinity levels （0.97 and 18.2 dS/m） and four levels of plant residues （control, alfalfa, wheat and corn） with three replications was performed. A first order kinetic model was used to describe the C mineralization and to calculate the potentially mineralizable C. The CO2-C evolved under non-saline condition, ranged from 814.6 to 4842.4 mg CO2-C/kg in control and alfalfa residue-amended soils, respectively. Salinization reduced the rates of CO2 evolution by 18.7%, 6.2% and 5.2% in alfalfa, wheat and corn residue-amended soils, respectively. Potentially mineralizable C （Co） was reduced significantly in salinized alfalfa residue-treated soils whereas, no significant difference was observed for control treatments as well as wheat and corn residue-treated soils. We concluded that the response pattern of C mineralization to salinity stress depended on the plant residue quality and duration of incubation.