Chemical scent constituents in urine of wolf (Canis lupus) and their dependence on reproductive hormones

The volatile components of castrated male and ovariectomized female wolf urine were investigated and correlated with the administration of testosterone or estradiol and progesterone. The results indicate that testosterone induces in the castrated male the formation of some compounds typically associated with the intact male, while reducing the levels of some compounds associated with castrated male and female. The production of some of the male compounds was also induced in the ovariectomized female, although at lower levels. Changes in hormone levels during treatment of females are reflected in the composition of the urinary volatiles. Consequently, many of these compounds could be used to communicate gender as well as reproductive status.     

新型三嗪酮类化合物的合成及生物活性研究

以三嗪酮类杀虫剂为先导,运用类同合成、生物电子等排理论,设计合成了25个新型三嗪酮类化合物。通过1H NMR、MS和元素分析对所合成的化合物进行了结构确认。初步生物活性测试结果表明,在试验浓度下部分化合物具有不错的生物活性。     

Discontinous volume changes of sodium acrylate-acrylamide-N,N′-methylenebisacrylamide copolymer gels in various solvent mixtures

Summery Volume behaviors of sodium acrylate-acrylamide-N,N-methylene-bisacrylamide copolymer gels in various solvent mixtures were examined. The gel samples having the same composition but different overall concentrations exhibited a discontinuous volume change at an appropriate solvent composition when immersed in methanol-water and tetrahydrofuran-water mixtures, but at some different solvent compositions when immersed in dioxane-water and acetonitrile-water mixtures because of significant flucutuation of the gel polymer-solvent mixture interaction.     

TiN/O''''-Sialon原位复合材料的抗氧化性能

通过对不同条件下原位复合制备的各种TIN／O′Sialon材料在空气中的氧化行为研究,考查了氧化温度、气孔率和TiW含量对材料抗氧化性能的影响。结果表明：当氧化温度升高到一定值时,通常材料表层会形成致密的“保护膜”,阻碍材料的进一步氧化;材料的气孔率和TIN含量越低,越易形成“保护膜”,反之,越不易形成“保护膜”。当材料的气孔率为30％以上,TiO2添加量为30wt％以上时,即使在更高的氧化温度下也不能形成“保护膜”。     

Effect of parthenin--a sesquiterpene lactone from Parthenium hysterophorus--on early growth and physiology of Ageratum conyzoides

A study was undertaken to assess the effect of parthenin—a sesquiterpene lactone from Parthenium hysterophorus—on the germination, growth, and some associated physiological changes in Ageratum conyzoides. The study reveals that germination and growth of A. conyzoides was severely reduced by parthenin in the concentration range of 50, 100, and 200 M, while at 400 M a complete inhibition of germination was observed. The radicle length of A. conyzoides was reduced more than the plumule length. Further, the content of the photosynthetic pigment chlorophyll was appreciably reduced in the leaves of test plants spray treated with parthenin at 200 M concentration. However, this inhibitory effect declined with the passage of time and at 10 days after treatment only a 25% reduction in chlorophyll content was observed compared to 76% on the first day after spray. Likewise, the cellular respiration measured through 2,3,5-triphenyl tetrazolium chloride was found to be less in the treated leaves, and the inhibitory response also declined with time. The content of proteins and carbohydrates decreased with the passage of time after parthenin treatment. The specific activities of the enzymes protease and - and -amylase were also adversely affected in the parthenin treated leaves. In the case of protease, the activity decreased with passage of time while those of the amylases increased. Thus, we conclude that parthenin affects the germination and growth of A. conyzoides by altering the contents of some macromolecules and the specific activities of some enzymes. Such observations may be helpful in further exploring parthenin's mode of action.     

包豪斯时代的"作坊"教学模式对现代陶艺教学的启示

主要探索包豪斯时代"作坊"教学模式对中国现代陶艺教育的影响,同时对包豪斯时代"作坊"教学模式的形成、发展也作了概括性探讨,并从时下现代高等院校陶艺教育中的教学内容、教育方式、开放式管理等方面作了一些粗浅的思考。     

含铜电镀污泥的固废属性鉴别研究

含铜电镀污泥来源不明、成分复杂,口岸不断发生以"铜矿"名义进口含铜污泥的现象,造成巨大经济损失和环境风险。借助X射线荧光光谱和衍射光谱分析,辅以外观、化学分析等手段,确定样品所含物质种类及含量,推断样品可能产生过程,对其属性进行判定,为口岸部门监管提供资料。     

Thermal dissociation of Ca(OH)2 at elevated pressures

The equilibrium Ca(OH)₂ ? CaO+H₂O has been studied at pressures of steam up to 50 bars and at temperatures of up to 800° C. The dissociation pressures determined are in agreement with the data derived by some previous workers at pressures of less than one bar but they conflict with data published for higher pressures. The results can be expressed by the relation over the range 530–800°c.     

From electrons to infrastructure: Engineering concrete from the bottom up

An approach rooted in fundamental, mechanistic models of concrete materials offers the only viable path for handling the enormous number of variables that are being introduced as new materials are added to the design space, and as new properties are mandated for a sustainable infrastructure. These models must begin at the smallest length scales relevant for concrete properties; in some cases this is the scale of electron interactions among atoms and ions. But concrete has complex chemical and structural properties that are manifested at greater length and time scales, so atomic scale models must ultimately be integrated with new models that capture behavior at mesoscopic and macroscopic scales. We refer to this methodology as the "bottom-up" approach because it proceeds from the smallest length scales. We describe this kind of modeling approach, include some recent results, and suggest some principles for collaboratively integrating multi-scale models.     

近期国内外聚氨酯弹性体的进展

本文论述了近期世界聚氨酯弹性体的发展已进入“平稳发展”和“高新技术开发”的时期，有些国家的产量已趋平稳或略有下降，而亚太地区（包括我国）发展较快，当今的特点是，国内外聚氨酯弹性体的技术有较大的进步，开发了许多高新技术和强功能性等新品种，从而开拓了更广泛的市场，今后有可能会在某些方面出现跃进性的发展。     

聚氨酯硬泡在防撬门生产中的应用

论述了硬质聚氨酯泡沫塑料作为防撬门内部填充材料的生产工艺及其优越性,指出前发泡、后静电喷涂面漆的工艺虽然优于后发泡工艺,但是必须选用开孔聚氨酯硬泡才能解决高温膨胀问题,并提出使用聚氨酯预制件代替金属材料密封门体内部活动件的可行性。     

Comparison of anodic dischargability of Li-B alloy with pure lithium in LiClO4-propylene carbonate

The dischargability of Li-B alloy is comparable with that of pure lithium in PC-LiClO₄ at 23° C. The alloy may find a useful application where safety considerations permit sacrificing some coulombic capacity versus unsupported lithium. Electrochemical measurements of the amount of lithium anodically oxidized at the lithium potential suggest that the alloy is a mixture of elemental lithium plus a Li-B compound whose stoichiometry is in the vicinity of Li₇B₆.     

Hydroacoustic Disturbances in Nuclear Explosions

Measurement techniques and some results obtained in underwater, abovewater, and underground nuclear explosions at the north test site are described. Parameters of hydroacoustic signals in a nuclear explosion in the Chernaya bay and in coastal underground nuclear explosions are described.     

关于《高分子化学》课程教学的几点思考

高分子化学是高分子材料专业的专业基础课。文章从几个方面对高分子化学课程教学进行初步探索,包括选择教学重点、兴趣点,合理有效利用多媒体与双语教学方式、开展师生互动教学,完善配套的实验与生产实践等,在教学的同时努力提高学生的专业素质。     

Estimating ammonia volatilization from unsaturated urea fertilized and urine affected soils by an indirect method

An indirect method for evaluating the emission of ammonia from urea-fertilized upland crops or urine-affected pastures, without affecting the plant's environment, was evaluated at Yanco, N.S.W., Australia and near Lincoln University, New Zealand. The parameters measured were the ammoniacal nitrogen concentration, pH and temperature in the aqueous phase at the soil's surface, and windspeed at a reference height. The combined effect of these influences on volatilization rate were incorporated into a linear relationship of the form F =k u _z 0, where F is the vertical flux of ammonia, determined by a micrometeorological method,u _z is the wind speed at some reference height above the soil,0 is the ammonia concentration in equilibrium with the liquid phase (calculated from the ammoniacal nitrogen concentration, pH and temperature) andk is a proportionality constant. Strong linear relationships of this kind were found for the data sets from both experiments. The respective correlation coefficients for the relationships at the two sites were 0.870 and 0.879, and the respective k values were 6.3 × 10^–5 and 7.5 × 10^–5. The field measurements require little in the way of specialized equipment (e.g. flat - surface pH electrode, ammonia electrode, anemometer) and are comparatively easy to carry out. The results suggest that with some further refinement, this technique could achieve application in the calculation of ammonia losses from small plots in the field.     

Bromate Surveys in French Drinking Waterworks

Two bromate surveys were made recently in order to evaluate the frequency of bromate appearance in drinking waters issued from waterworks including one or two ozonation steps. The First survey was carried out on 47 waterworks. Two sampling campaigns were analyzed in cool and warm seasons. The objective of the second survey was to follow, during 4 to 10 months, at 12 selected waterworks.

The aim of this paper is to present the data obtained and to try to model for some waterworks the bromate formation by means of some important parameters (Br, O₃/DOC, T° and pH) of water to ozonate.

The main conclusion is that the bromate presence in distributed drinking waters is a reality for waterworks using ozonation steps, especially in warm period of the year. In the case of some waterworks, disinfection by sodium hypochlorite increased bromate levels in distributed water.

As shown by others on a laboratory-scale level, a multi-linear regression allows us the prediction of the bromate formation from some determining parameters, for some waterworks. However, the poor values of the linear regression lead us to have some doubts about its universal application in the real situation of an operating waterworks. A better evaluation of “C.t” will be required in the future in order to get a better prediction by the use of multi linear regression.     

Water permeation and solute rejection behaviors of a novel hydrophilic polyamide membrane

Summary The poly(BOL) membrane prepared by casting polymerization exhibited an excellent fractional solute-rejection behavior in the aqueous solution, having a comparatively sharp boundary region at the molecular weight range of about 200 to 1400, together with an extremely high water permeability. These conspicuous behaviors, as well as a great capacity for water absorption, may result from some delicate arrangement of polar hydrophilic and nonpolar hydrophobic microdomains probably formed along and between the polymer chains.     

THE EFFECT OF LIQUID PHYSICAL PROPERTIES ON DRIFT VELOCITY

Drift velocity is a very important paramcter for predictirg the pool volumetric void fraction. Two-phase system of gas and high viscous liquids pool is encountered in various engineering applications. A review of the literature shows no data for explaining the effect of highly viscous liquids on the drift velocity. This paper's analysis shows that there is a considerable influence. It is shown that the foaming behaviour of liquids is dependent on the surface properties. For some highly viscous liquids at a given superficial gas velocity, the viscosity changes with time. The effect of "foam" and "time" on drift velocity is clearly elucidated.     

Recent advances in the rheooptical characterization of silicon-containing networks

Recent advances in the various theories of strain-birefringenece of polymer networks are presented. The classical theories as well as the more advanced models are outlined together with some recent theoretical results on poly (dimethylsiloxane). Reference to work on other Si-containing polymers is made. The problems of intermolecular correlations occurring in polymer networks and their effect on the observed optical properties are discussed with reference to the optical-configuration parameter. Conclusions report areas of current research.This review was presented at the Second International Topical Workshop, Advances in Silicon-Based Polymer Science.     

VACUUM CONTACT DRYING OF SEEDS

The seeds of white and red clover were dried in contact dryers under 75 to 90% vacuum and at wall temperature 45 to 50'C. The main advantage of the vacuum contact drying in relation to convective one is energy saving. The mathematical "penetration model" with some simplifications was used for calculation of the rate-of-drying curves. The experimental and theoretically ' provided rate-of-drying curves do not differ significantly.