Design of a PFW European type impact crusher

介绍了一种PFW欧版反击式破碎机,由于该机采用了重型转子装置,取得了较好的破碎效果。该破碎机结构科学合理,使用安全可靠,维护方便快捷。与传统反击式破碎机相比,不仅延长了设备的使用寿命,缩短了耐磨件的更换时间,而且提高了生产效率,增加了经济效益。     

前言

自20世纪初期,德国化学家EmilFischer首先合成了甘氨酸二肽片段,并第一次提出“peptide”（多肽）这一名词,多肽化学的研究已经历了100多年的发展．1953年,Vigneand小组首次完成了生物活性肽催产素的合成,并因此于1955年获得了诺贝尔化学奖．1963年,Merrifield提出了多肽固相合成法,并发明了第一台多肽自动合成仪,大大简化了多肽合成的流程、提高了合成的效率,从而促使多肽化学实现了飞跃式发展,Merrifield也因此获得了1984年诺贝尔化学奖．1965年,我国科学家完成了牛结晶胰岛素的合成,     

应用控制气氛光谱法提高难熔金属中难熔杂质分析灵敏度

控制气氛光谱分析是利用气体的不同物理及化学特性,改善放电区域中的光辐射作用。本文设计了两种控制气氛气室,试验了以Ar与O_2及Ar与CO_2作为控制气氛时对难熔金属氧化物中难熔杂质的有关条件,制订了五种分析方法。这些方法,由于利用了控制气氛,提高了对难熔杂质的蒸发速度,压抑了主体影响,给出了良好的激发条件,降低了背景,消除了氰带,从而提高了Ta,Nb,Zr,Hf氧化物中难熔杂质元素如Ti,Al,V,Zr,Mo,W,Nb,Ta的分析灵敏度。     

储氢合金电极的表面修饰研究

利用等离子体技术对AA型MH/Ni电池的储氢合金电极进行了镀覆导电膜层的表面修饰,用XRD及SEM对电极结构进行了表征.极片经过表面修饰的电池,其内阻降低了24％,放电容量有了明显提高,5C (7.5 A) 放电容量提高了200 mA•h,放电平台电压提高了约0.14 V,导电膜层还起到了电极保护层的作用,抑制了合金的粉化,提高了电池的循环稳定性.同时,电池内压显著降低,电池性能有了较大改善.     

氧化锌对MCM-22分子筛晶化的影响

 采用静态水热合成法,以六亚甲基亚胺为模板剂,在氧化锌存在下合成了MCM-22分子筛,考察了氧化锌对MCM-22晶化的影响. 结果表明,少量氧化锌的添加抑制了杂晶的生成,缩短了晶化诱导期,提高了晶化速度,扩大了硅铝比的范围,降低了模板剂的用量.     

食品安全与健康——深圳市卫生部门食品安全保障体系

回顾了国际国内的食品安全问题以及管理现状,着重介绍了深圳市卫生部门食品安全保障工作.近几年,深圳市有效运行了食品污染物监测网络,基本掌握了食品安全存在的问题,通过对问题食品的追溯,从根本上着手解决问题,控制了污染食品进入餐桌;以风险评估作为科学手段,做好重点食品污染物的监测预警;引导和提醒消费者提高自我保护意识,为政府制定相关决策提供了依据,从而显著地减少了食源性疾病的发生,有效地保障了公众的身体健康.     

非理想气体的逸度因子和非理想溶液的活度系数

对单组分非理想气体,推导了它的逸度因子的微分方程式。对多组分非理想气体,推导了各组分逸度因子满足的微分方程式,定义了一个总逸度因子,并找到了总逸度因子和各组分逸度因子之间的关系。同样,对非理想溶液,推导了各组分活度系数满足的微分方程式,定义了非理想溶液的总活度系数,并找到了两者满足的关系。最后分析了逸度因子和活度系数之间的异同点。     

塑料工业技术开发热点及其市场预测

本文简述了塑科将成为未来世纪的主要工业材料,介绍了80年代至本世纪末,世界主要国家塑料工业的主要品种,产量,生产能力;分析了90年代世界塑料市场供需状况,并重点探讨了中国塑料市场供需矛盾,预测了2000年需求总量,提出了今后发展应注意的关键问题。最后,重点探讨了世界塑料工业几个主要品种,今后发展趋势及一些关键技术的开发热点。     

碳化对超细Fe-Mn催化剂CO加氢反应行为的影响

以超细Fe-Mn催化剂为前驱体,对其进行了CH₄/H₂气氛下的高温碳化及反应行为研究。结果表明,高温碳化后,催化剂比表面积明显降低,主要物相结构为FeO-MnO尖晶石和α-Fe相,并有大量碳化铁微晶生成。在CO加氢反应中,碳化过程明显提高了烯烃选择性,降低了CH₄选择性,促进了链增长。结果认为,碳化过程改变了催化剂表面化学性质,增强了表面碱性,抑制了二次加氢反应,提高了烯烃选择性。     

农林高校基础化学多层次课程体系和教学内容的改革与实践

以农林高校基础化学课程体系和教学内容改革为抓手,构建了农科特色鲜明的多层次课程体系,优化设计了教学内容,增强了教学的针对性,突出了学生个性的发展,为农科院校创新人才的培养奠定了重要的化学基础。     

Determination of betaines in vegetable oils by capillary electrophoresis tandem mass spectrometry--application to the detection of olive oil adulteration with seed oils

A CE–tandem mass spectrometry (MS²) methodology enabling the simultaneous determination of betaines (glycine betaine, trigonelline, proline betaine and total content of carnitines) in vegetable oils was developed. Betaines were derivatized with butanol previous to their baseline separation in 10 min using a 0.1 M formic acid buffer at pH 2.0. Ion trap conditions were optimized in order to maximize the selectivity and sensitivity. Analytical characteristics of the proposed method were established by evaluating its selectivity, linearity, precision (RSDs ranged from 4.8 to 10.7% for corrected peak areas) and accuracy by means of recovery studies (from 80 to 99%) and LODs and LOQs at 0.1 ppb level. The method was applied for the determination of the selected betaines in seed oils and extra virgin olive oils. MS² experiments provided the fingerprint fragmentation for the betaines identified in vegetable oils. In extra virgin olive oils, carnitines were not detected, making it possible to propose them as a feasible novel marker for the detection of adulterations of olive oils. Application of the developed method for the analysis of different mixtures of extra virgin olive oil with seed oil (between 2 and 10%) enabled the detection and quantitation of the total content of carnitines. The results obtained show the high potential of the developed method for the authentication and quality control of olive oils.     

Pyrolysis of vegetable oil soaps—Palm, olive, rapeseed and castor oils

Saponified, palm, olive, rapeseed and castor oils were pyrolysed (at 750 °C for 20 s) by pyrolysis gas chromatography with mass selective and flame ionisation detection (Py-GC/MSD and FID) to clarify their thermochemical behaviours. The liquefiable compounds recovered from palm, olive and rapeseed oils mainly contained linear alkenes (up to C₁₉) and alkanes (up to C₁₇), both similar to those found in gasoline (C₄-C₁₀) and diesel fuel (C₁₁-C₂₂) boiling range fractions of petroleum, whereas in the case of castor oil a significant amount of undesired oxygen-containing products (e.g., ketones and phenols) were formed. The obtained data on reaction mechanisms can also be utilised in applications where various biofuels are produced, for example, from the extractive-derived by-product (tall oil) of kraft pulping.     

傅里叶变换红外吸收光谱识别五种植物油的研究

以花生油、大豆油、芝麻油、棉籽油和米糠油为样品,采用傅里叶变换红外光谱仪,采集傅里叶变换红外吸收光谱,对光谱预处理后,提取红外特征信息,以1746cm-1和2855cm-1处的吸收峰面积比值为横坐标,1099cm-1处与1119cm-1处的吸收峰面积比为纵坐标,在Origin6.0上做出二维分布图,对各种油脂进行识别分析。结果显示,大豆油与其它4种油脂之间有明显区分;大豆油、花生油和芝麻油分布效果好,但棉籽油各样品点之间比较分散;能与其它油脂区分开的有以下几种分布花生油明显区别于芝麻油、棉籽油和大豆油;米糠油明显区别于棉籽油和大豆油。分布有交叉的油脂有米糠油与花生油或芝麻油有交叉,棉籽油与芝麻油有交叉。     

用NICOLET5SXC富里利叶变换红外光谱仪对中成药作GC/FTCR分析研究——Ⅱ.药用油的GC/FTIR快速分析

本文用Nicolet 5SXC对驱风油,本草油,白花油进行了GC/FTIR快速分析,在没有标准品的条件下,对其中十六个主组分进行了定性研究,用Aldrich Vapor Librasy进行了谱库检索,取得了较为满意的结果。     

Effects of Thai Local Ingredient Odorants,Litsea cubeba and Garlic Essential Oils,on Brainwaves and Moods

The functional food market is growing with a compound annual growth rate of 7.9%. Thai food recipes use several kinds of herbs. Lemongrass, garlic, and turmeric are ingredients used in Thai curry paste. Essential oils released in the preparation step create the flavor and fragrance of the famous tom yum and massaman dishes. While the biological activities of these ingredients have been investigated, including the antioxidant, anti-inflammatory, and antimicrobial activities, there is still a lack of understanding regarding the responses to the essential oils of these plants. To investigate the effects of essential oil inhalation on the brain and mood responses, electroencephalography was carried out during the non-task resting state, and self-assessment of the mood state was performed. The essential oils were prepared in several dilutions in the range of the supra-threshold level. The results show that Litsea cubeba oil inhalation showed a sedative effect, observed from alpha and beta wave power reductions. The frontal and temporal regions of the brain were involved in the wave alterations. Garlic oil increased the alpha wave power at lower concentrations; however, a sedative effect was also observed at higher concentrations. Lower dilution oil induced changes in the fast alpha activity in the frontal region. The alpha and beta wave powers were decreased with higher dilution oils, particularly in the temporal, parietal, and occipital regions. Both Litsea cubeba and turmeric oils resulted in better positive moods than garlic oil. Garlic oil caused more negative moods than the others. The psychophysiological activities and the related brain functions require further investigation. The knowledge obtained from this study may be used to design functional food products.     

四苯(基)苯基多乙烯基硅油的合成及结构测定

<正> 多乙烯基硅油是高温硫化硅橡胶的集中交联剂,当无耐热填料时,所得硫化胶的耐热性不高。为了使多乙烯基硅油既具有集中交联作用,又赋予耐热性,本文采用Diels-AIder反应合成了含有四苯(基)苯基的多乙烯基硅油。前文曾合成多种多苯(基)苯基有机硅化合物,但实验在封管内进行,诸多不便,投量也甚少,为此,改用高沸点溶剂(α-氯萘),在常压下反应,得到了高产率的四苯(基)苯基多乙烯基硅油:     

A novel approach to the rapid assignment of 13C NMR spectra of major components of vegetable oils such as avocado,mango kernel and macadamia nut oils

Assignment of ¹³C nuclear magnetic resonance (NMR) spectra of major fatty acid components of South African produced vegetable oils was attempted using a method in which the vegetable oil was spiked with a standard triacylglycerol. This proved to be inadequate and therefore a new rapid and potentially generic graphical linear correlation method is proposed for assignment of the ¹³C NMR spectra of major fatty acid components of apricot kernel, avocado pear, grapeseed, macadamia nut, mango kernel and marula vegetable oils. In this graphical correlation method, chemical shifts of fatty acids present in a known standard triacylglycerol is plotted against the corresponding chemical shifts of fatty acids present in the vegetable oils. This new approach (under carefully defined conditions and concentrations) was found especially useful for spectrally crowded regions where significant peak overlap occurs and was validated with the well‐known ¹³C NMR spectrum of olive oil which has been extensively reported in the literature. In this way, a full assignment of the ¹³C{1H} NMR spectra of the vegetable oils, as well as tripalmitolein was readily achieved and the resonances belonging to the palmitoleic acid component of the triacylglycerols in the case of macadamia nut and avocado pear oil resonances were also assigned for the first time in the ¹³C NMR spectra of these oils. Copyright © 2009 John Wiley & Sons, Ltd.     

Determination of acrolein in french fries by solid-phase microextraction gas chromatography and mass spectrometry

The frying of foods in the home can be a cause of indoor pollution due to the formation of acrolein. The emission of acrolein formed during frying in soybean, corn, canola, sunflower and palm oils was studied. A GC/MS method has been developed to determine acrolein in French fries using SPME as the sampling technique after derivatization with 2,4-dinitrophenylhydrazine (DNPH). Optimum SPME conditions included desorption at 250°C for 2min after an adsorption time of 10min at room temperature. The method presented good resolution, repeatability, detection and quantification limits, and linearity of response. French fries were prepared in five different oils with four frying steps. The results showed that changes in acrolein concentration occurred after frying potatoes in different types of oil and at different frying cycles. Potatoes fried in soybean oil contained the lowest concentration of acrolein. Shoestring potatoes contained a lower concentration of acrolein than potato chips and French fries, respectively, because of the higher surface/volume ratio.     

Shotgun Lipidomic Analysis for Differentiation of Niche Cold Pressed Oils

The fast-growing food industry is bringing significant number of new products to the market. To protect consumers’ health and rights, it is crucial that food control laboratories are able to ensure reliable quality testing, including product authentication and detection of adulterations. In our study, we applied a fast and eco-friendly method based on shotgun-lipidomic mass spectrometry for the authentication of niche edible oils. Comprehensive lipid profiles of camelina (CA), flax (FL) and hemp (HP) seed oils were obtained. With the aid of principal component analysis (PCA), it was possible to detect and distinguish each of them based on their lipid profiles. Lipidomic markers characteristic ofthe oils were also identified, which can be used as targets and expedite development of new multiplexed testing methods.     

Differential scanning calorimetry: a potential tool for discrimination of olive oil commercial categories

Differential scanning calorimetry thermograms of five commercial categories of olive oils (extra virgin olive oil, olive oil, refined olive oil, olive-pomace oil and refined olive-pomace oil) were performed in both cooling and heating regimes. Overlapping transitions were resolved by deconvolution analysis and all thermal properties were related to major (triacylglycerols, total fatty acids) and minor (diacylglycerols, lipid oxidation products) chemical components.All oils showed two well distinguishable exothermic events upon cooling. Crystallization enthalpies were significantly lower in olive oils due to a more ordered crystal structure, which may be related to the higher triolein content. Pomace oils exhibited a significantly higher crystallization onset temperature and a larger transition range, possibly associated to the higher amount of diacylglycerols. Heating thermograms were more complex: all oils exhibited complex exo- and endothermic transitions that could differentiate samples especially with respect to the highest temperature endotherm.These preliminary results suggest that both cooling and heating thermograms obtained by means of differential scanning calorimetry may be useful for discriminating among olive oils of different commercial categories.