TiCl_4水解制备金红石型TiO_2纳米粉

实验以 Ti Cl4 为主要原料 ,采用直接水解法制备出了 Ti O2 样品。经差热 -热重 ( DTA-TG)、X-射线衍射 ( XRD)、透射电子显微镜 ( TEM)和比表面 ( BET)分析 ,得出样品 Ti O2 的晶型为金红石型 ,其粒子近似呈球形 ,各个晶面所对应的粒径基本一致 ,分布在 7.0～ 12 .0 nm之间 ,平均粒径为 10 .5nm,对应的比表面积和孔容积分别为 166m2 /g和 0 .12 m L/     

贻贝保健食品的研究

作者运用营养学中的互补及平衡原理,以贻贝为主要开发利用对象,研制出贻贝保健食品——东海三豪口服液等。工艺研究重点解决各海珍原料中活性物质的分离、营养物质利用度优化及产品基料的脱腥脱色技术等,效果理想。制成品分析表明,贻贝保健食品确属高营养、高生物活性(生物试验结果见另文)的双功能食品,并保持了鲜明的海洋食品特色。     

从鳕鱼碎肉中提取水解蛋白

用蛋白酶水解法从鳕鱼加工废弃物－鳕鱼碎肉中提取水解蛋白。鳕鱼碎肉经枯草杆菌ＡＳ１．３９８中性蛋白酶２４０ＩＵ／ｍｌ，ｐＨ７．０，５０℃下水解２ｈ；再经黄曲霉ＩＦＦＩ２３４２（蛋白酶活力２０００ＩＵ／ｇ）１．５％（ｗ／ｖ），５０℃，ｐＨ６．０下水解６ｈ以脱苦味。水解液经真空浓缩后喷雾干燥得水解蛋白粉。该制品易溶于水，无苦味，有海鲜味。其氨基酸组成合理，是优良的蛋白质制品。     

Methyl halide hydrolysis rates in natural waters

International regulations are under consideration for methyl bromide because of its high time dependent ozone depletion potential. Geocycling of the species is not well understood, and removal may occur in several types of natural water incuding the oceanic and those in soils. The hydrolysis reaction is a dominant loss pathway in environmental aqueous systems, but rate constants have generally been reported only in distilled water and at greater than room temperature. Here we present measurements in sodium chloride solutions and in seawater in addition to pure water, and at temperatures across the oceanographic range. The reaction could be followed even in solutions near the freezing point because product methanol was monitored in the method of initial rates. Time constants for methyl bromide hydrolysis fall between 10 and 1000 days over the temperatures of the sea, and are always within an order of magnitude of the fastest abiotic destruction mode, chlorination. Activation energies for the two processes are similar so that the ratio of their time scales does not vary with oceanic location. Hydrolysis rate constants are also listed for the closely related compounds methyls iodide and chloride. Solvolysis of the methyl halides in natural waters acts as a source of methanol to the ocean and atmosphere.     

The Speciation of (CH3)2Sn2+ in Electrolyte Solution Containing the Major Components of Natural Waters

Hydrolysis constants of dimethyltin(IV) cation, in different salt solutions (CaCl₂: 0.15 I 0.90; MgCl₂: 0.30 I 0.60; NaCl-–NaClO₄, NaCl-–NaNO₃ mixtures: I = 3; NaCl-–Na₂SO₄ mixtures: I = 1 mol dm^-3) were determined by potentiometric ([H⁺]-glass electrode) measurements. These data, together with previous data (De Stefano et al., 1996b) were interpreted in terms of DHT (Debye–Hückel type) and Pitzer equations. The mixed electrolyte solution results also allowed us to obtain and parameters for the Pitzer equation. Calorimetric measurements were made at different ionic strengths in order to find the temperature dependence of hydrolysis constants and of the relative interaction parameters. The body of results allows us to determine the speciation of natural waters in a wide range of ionic strengths and temperatures.     

Factors influencing ammonia volatilization from urea in soils of the shortgrass steppe

The effects of soil moisture, temperature, and humidity treatments on urea hydrolysis and NH₃ volatilization were assessed in the laboratory. Field studies were conducted to determine seasonal NH₃ losses from simulated urine patches applied to contrasting soils of a representative hillslope of the shortgrass steppe region in the North American Great Plains.Losses of NH₃–N were most influenced by soil moisture. The effects of temperature and humidity on total, or temporal, losses of NH₃ were dependent on soil moisture. Losses ranged from 18.5% under conditions of low-temperature/high-humidity/wet soil to 7.7% under conditions of high-temperature/low-humidity/dry soil. In contrast, urea hydrolysis was not affected by soil moisture.Losses of NH₃–N from simulated urine applied to field plots ranged from 1.5% on footslope soils in summer to 14.1% on backslope (midslope) soils in summer, whereas losses were 8.1% on back-slope soils in winter. Factors such as soil texture, microbial activity, and plant productivity along a toposequence had larger effects than climatic variables on variation in the volatile losses of NH₃–N from this grassland.This paper is a report on the work presented at the international symposium Influence of marine and terrestrial biosphere on the chemical composition of the atmosphere, held in Mainz, F.R.G., on 16–22 March 1986.     

Organic geochemistry of Recent equatorial deltaic sediments

The organic matter of recent deltaic sediments cored in the Mahakam delta, East Kalimantan, has been studied before and after physical fractionation into sands >50 μm, silts 5–50 μm and clays <5 μm. Both the lipid and non-lipid components have been investigated.Weight, carbon and nitrogen fractionation budgets were used to define three types of samples, depending on coarse particle contributions to the total amount of organic matter: a = a first type with more than 50% of the O.M. in the coarse particles, high C/N ratios and O.M. content, b = an intermediary type with medium C/N ratios and O.M. content, each fraction having quite the same O.M. content, c = a third type with less than 5% of the whole O.M. in the sands and the lowest C/N ratios and O.M. content.Concerning the global organic characteristics of the fractions, a systematic increase of C/N ratios occurs when going from clays to sands; the finer the fraction is, the more nitrogenous the compounds are. This enrichment in nitrogen is related to a persistent high rate of hydrolysable material either for argillaceous organic matter-poor sediments or for the clay fractions of all types of samples. Conversely, the type (a) coarse sediments, in particular the sandy components were resistant to acid hydrolysis with burial.Concerning the geochemical markers signatures of granulometric fractions, the distribution patterns of n-alkanes and n-fatty acids are characterized by the predominance of high molecular weight compounds >C₂₂. Carbon preference index (CPI) values are higher in the sands and silts, reflecting their enrichment in continentally-derived vegetation debris. For type (c), the fractionation revealed markers of microbial activity within the clay fractions. For all types of samples, we observed an increase with burial of the n-alkane and n-fatty acid concentrations, particularly in the clay fractions, suggesting possibly a better preservation and/or affinity of lipids with the finest fractions.     

Analytical problems in determining peptide nitrogen in the humic fractions of three Italian soils

Peptides were released from organic matter fractions of three Italian soils (humin, humic and fulvic acids), when the samples were hydrolyzed in Ba(ON)₂-saturated solution at 105°C for 2 hr. The peptides obtained were separated using electrophoresis and paper chromatography. The presence of polypeptides in the soil organic matter was indicated by: (1) their hydrolysis by pronase; (2) the amino acids released by 6 N HCl hydrolysis; (3) The comparison of i.r. spectra of humic fractions before and after hydrolysis with 6 N HCl.Attempts at isolating the native proteinaceous compounds using electrophoresis in polyacrylamide gel failed; additionally, our attempts to hydrolyze proteinaceous components enzymatically in unfractionated soil organic matter, as well as in its fractions, before and after methylation, with pepsin, papain and pronase, were unsuccessful. Pronase demonstrated a weak proteolytic activity only at very low substrate-enzyme ratios (20 : 1) in humic and fulvic fractions and in whole phyrophosphate extract. Deproteinated substrates treated with pronase also released free amino acids, suggesting autodigestion.In humin, humic and fulvic fractions we found a total amino acid content of 40–45%, 12–24% or 1–85, respectively. Amino acid recovery from single fractions was about 70–80% of the total content in the unfractionated soil.