浸渍镁盐对镁铬砖性能的影响

用镁盐溶液对两种不同Cr2O3含量的电熔再结合镁铬砖进行了真空浸渍处理,并对浸渍前后试样的物理性能和孔径分布进行了分析,用静态坩埚法和高压釜反应法分别对浸渍前后试样的抗渣性和抗水化性能进行了比较。结果表明:经镁盐溶液浸渍后,镁铬砖的显气孔率显著下降,体积密度增大,常温耐压强度和常温抗折强度明显增大;试样中孔径>10μm的孔容积百分率由浸盐前的84.13%下降到浸盐后的67.67%;浸渍后试样的抗水化性能显著提高,抗渣性能得到一定改善。     

Composition and technological properties of coals from Mongolian deposits

The main characteristics of the composition of coals from Mongolian deposits and their reactivity in thermal dissolution and coking processes were determined. The thermochemical conversion of coals into hydrocarbon products was studied. It was found that Tavantolgoi coal is characterized by high coking properties with the yield of carbon residue to 82.3%. The composition of semicoking tar was studied by chemical analysis and IR spectroscopy.     

氧化铬绿颜料性能影响因素分析

对德国Bayer公司和国内市售的三种有代表性的氧化铬绿样品 ,进行了晶体结构、元素含量、热失重、色度色差、粒度粒径等的分析 ,讨论了它们对颜料性能产生的影响     

Composition and properties of coals from some deposits in Mongolia

Nine coal samples from different deposits in Mongolia were studied with the use of a set of chemical and physicochemical methods of analysis (proximate and ultimate analyses, low-temperature extraction, the chemical analysis of ashes, thermogravimetric analysis, IR spectroscopy, and thermal dissolution) for evaluating their composition and chemical-engineering properties.     

铬矿对镁质浇注料性能的影响

在以8～5mm(18%,质量分数,下同)、5～3mm(18%)、3～1mm(22%)的97高纯镁砂和≤1mm(12%)的97电熔镁砂为骨料,≤0.088mm(20%)的97电熔镁砂,SiO2微粉(2%),α-Al2O3微粉(5%),亚白刚玉粉(3%)为基质细粉,六偏磷酸钠等为复合分散剂的镁质浇注料基础配方中,分别用5%、8%、15%的铬矿砂(0.833～0.178mm和≤0.088mm的混合料)等量替代≤0.088mm的电熔镁砂制成不同铬矿含量的镁质浇注料试样。分别测试样经110℃24h、1100℃3h和1550℃3h处理后的线变化率、显气孔率和抗折强度,并利用SEM和EDX分析1550℃3h处理后试样的显微结构。结果表明:(1)镁质浇注料中加入适量的铬矿,有利于提高方镁石晶粒间的直接结合强度,使材料抗折强度提高,显气孔率下降;适量微裂纹的产生有利于浇注料抗热震性的提高。铬矿的适宜加入量为5%～8%。(2)SEM和EDX分析表明,试样经1550℃3h处理后,铬矿和镁砂呈相互扩散,并脱溶出二次尖晶石,增强了晶粒间的直接结合程度,从而有效地提高了镁质浇注料的力学性能。     

还原气氛对高铬砖性能的影响

为了有效提高高铬砖的常温物理性能和抗侵蚀性能,延长其在水煤浆加压气化炉中的使用寿命,在埋炭条件下,分别于1350、1450和1550℃烧成高铬砖,并与1700℃空气中烧成试样对比,研究了烧成气氛(埋炭和空气气氛)对高铬砖体积密度、显气孔率、常温耐压强度和抗熔渣渗透性能的影响。结果表明:随着温度升高,高铬砖的显气孔率下降、体积密度增加,而1450℃埋炭烧成高铬砖的常温耐压强度最高,达到214MPa;埋炭能显著降低高铬砖的烧成温度和改善其显微结构;1450℃埋炭烧成高铬砖的抗熔渣渗透能力优于1700℃空气中烧成试样的。     

Composition and properties of coals from the Yurty coal occurrence

Coals from the Yurty coal occurrence were studied. It was found that the samples were brown non-coking coals with low sulfur contents (to 1%) and high yields of volatile substances (V ^daf to 53.4%). The high heat value of coals Q _s ^daf was 20.6–27.7 MJ/kg. The humic acid content varied from 5.45 to 77.62%. The mineral matter mainly consisted of kaolinite, α-quartz, and microcline. The concentration of toxic elements did not reach hazardous values.     

Appraisal of chrome ores from several deposits

Chrome ore shipments from the Pobuzhskoe deposit (Ukraine), Turkey, and the United Arab Emirates (UAE) were appraised for chemical and mineral composition. Laboratory tests were made and trial lots of refractories were fabricated. The Turkish and UAE chrome ore and also Pobuzhskoe chrome ore with 39 to 45% Cr₂O₃ were found suitable for the manufacture of chrome refractory products.     

Distinction of gem spinels from the himalayan mountain belt

Gem spinel deposits in Myanmar, Vietnam and Tajikistan have their formation in association with Himalayan orogenesis. Gem-quality orange, pink, red and purple spinels from deposits at Mogok (Myanmar), Luc Yen (Vietnam), and Kuh-i-Lal (Tajikistan) have been investigated by 'standard' gemological testing and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Microscopic examination yielded apatite and calcite inclusions together with octahedral negative crystals to be most frequently present in Mogok spinels. The presence of dislocation systems and titanite inclusions are indicative inclusion features for spinels from Luc Yen. Trace elements such as Ti, Fe, Ni, Zn, Zr and Sn differ slightly in spinels from the sources investigated. A distinction of spinels from these deposits is therefore possible by trace element chemistry. This is especially helpful for gem spinels, which often show few inclusions or completely lack inclusion features.     

Antioxidant properties of hymatomelanic acids from brown coal

The antioxidant activity of a low-temperature fraction of hymatomelanic acids from brown coal in a model process of the radical chain oxidation of cumene was determined using a gas-volumetric method. Their antiradical activity was evaluated by spectrophotometry using a reaction with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The pronounced ability of hymatomelanic acids to cause antioxidant and antiradical effects in model systems was demonstrated. It was found that the antioxidant and antiradical activities increased with the concentration of hymatomelanic acids. The determined properties of hymatomelanic acids from brown coal can be useful for technical and biomedical applications.     

Antioxidant properties of humic acids from brown coal

It was demonstrated by a gas-volumetric method that humic acids from brown coal exhibit pronounced antioxidant properties, being the effective inhibitors of the model reactions of initiated radicalchain oxidation of hydrocarbons (cumene and ethylbenzene). This makes it possible to recommend humic acids for use as effective antioxidants for technical purposes and as promising biologically active natural antioxidants for the development of new classes of pharmaceuticals for medicine.     

Composition of bile acids in ruminants

The bile acids found in sheep bile, beef bile, beef feces, sheep fetus bile, and beef fetus bile have been analyzed by using conventional techniques. Animals maintained on natural and purified diets were used. The bile acids are a complex mixture of isomeric hydroxy- and keto-5β-cholanoic acids which were substituted at one or several of the carbon atoms 3, 7, and 12. Cholic acid is the predominant bile acid found in these species. Deoxycholic acid was the major product formed from cholic acid when the animals were on a natural diet but the concentration of 3α, 12α-dihydroxy-7-keto-5β-cholanoic acid was elevated in the animals that were maintained on a high concentrated purified diet (without roughage). The fetus bile was found to contain nearly all of the bile acids found in the bile of the mature animal but in different concentrations.     

Composition and properties of coals from the Saikhan-Ovoo deposit in Mongolia

The main performance characteristics of coal from the Saikhan-Ovoo deposit in Mongolia were determined. This coal corresponds to a high metamorphic rank, which corresponds to lean coal transitional to anthracite. It is characterized by high yield of semicoke, high calorific value, and low sulfur content. Iron compounds (60.2%) predominate in the mineral matter of coal with a small participation of silicon, aluminum, calcium, and other metal compounds. The concentrations of the toxic metals Sr, Mn, Zn, and Cu are no higher than the maximum permissible concentrations. The supramolecular structure of the organic matter of coal mainly consists of closely packed graphite-like clusters containing on average 6.7 aromatic layers. A small fraction of carbon (about 20%) is structured as γ-components at the periphery of clusters. Active carbon was obtained by thermal steam activation. Its structural characteristics and sorption capacity for iodine and methylene blue were determined.     

Composition and biosynthesis of fatty acids inPyramimonas grossii

The green algaPyramimonas grossii orginating in the coastal waters of the Atlantic Ocean Argentina was subcultured until a monoalgal culture was obtained. The fatty acid composition of the alga grown in a mineral medium at 12 C was determined by gas liquid chromatography (GLC) on 2 columns. The major fatty acids were oleic, linoleic, palmitic and α-linolenic acids, but the 20-carbon polyunsaturated acids, 20∶4ω6 and 20∶5ω3, respectively, belonging to the linoleic and α-linolenic series, were also found. Incubation with [¹⁴C] oleate, [¹⁴C] acetate, [¹⁴C] linoleate and [¹⁴C] α-linolenate suggests that linoleate is not directly converted to α-linolenate. [¹⁴C] Acetate was easily converted to palmitic, palmitoleic and oleic acids. However, after 48 hr of incubation, only traces of radioactivity were detected in linoleic acid and no label was found in α-linolenic acid.     

Composition and positional distribution of fatty acids in phospholipids isolated from pork muscle tissues

The composition and positional distribution of fatty acids in phospholipids isolated from four locations of a hog carcass is presented. Variations in fatty acid composition of phospholipids were found depending upon the location in the carcass. The total unsaturated fatty acid content averaged 34.3 mole % for lecithin, 52.5 mole % for phosphatidylethanolamine, 40.3 mole % for phosphatidylserine and 41.3 mole % in sphingomyelin. The cephalins had a much higher percentage of polyunsaturated fatty acids than lecithin. The chief saturated fatty acid in lecithin and sphingomyelin was palmitic and in cephalins it was stearic. A snake venom enzyme preparation(Crotalus adamanteus) hydrolyzed primarily unsaturated fatty acids in phosphoglycerides and the higher the percentage of unsaturation within the fatty acid the higher percentage of hydrolysis occurred. The unsaturated fatty acids were found chiefly at the theβ-position and the saturated fatty acids at thea-position in the phosphoglycerides. Michigan State Agricultural Experiment Station Publication No. 3389. Supported by the U.S. Public Health Service Research Grant No. GM 08801-03.     

Composition and properties of the fractions of a water-ethanol extract from peat

A water-ethanol extract from cotton grass-sphagnum peat was prepared. Six fractions were separated from the peat extract using sequential extraction with a system of solvents with linearly increasing polarities. The chemical composition of each of the fractions was studied, and the main physicochemical characteristics of these fractions were determined. The biological activity of the initial extract and its individual fractions was examined.     

Spectral properties of linoleic and linolenic acids prepared by debromination

Summary Modified procedures are described for the preparation of linoleic and linolenic acids which remove and/or prevent the formation of conjugated acids. The importance of spectrophotometric measurements as a criterion of purity is emphasized. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.