论控制分析与成品分析的区别

控制分析与成品分析有许多不同的要求,合理安排分析的标准,可及时准确地反映样品的分析数据,或者说合理化分析的时间,既减少了分析时间又降低了分析成本。     

基于仪器分析技术在油品分析研究

从油品分析概述入手,分析了油品光谱法分析的重要性,之后注重探讨了基于仪器分析技术的油品分析,主要包括气相色谱法、高效液相色谱法、质谱法、近红外等,进一步促进仪器分析技术在油品分析中的应用和发展。     

浅谈水质分析

文章介绍了水质分析的定义,水质分析的意义,水质分析的质量控制以及水质分析的发展前景。重点介绍了水质分析质量控制的因素以及措施。     

丙烯酸乙酯反应液组成分析方法的改进

针对丙烯酸乙酯反应液组成分析中存在的基线漂移、分析时间长的问题，根据色谱理论，在试验的基础上，选择合适的分析条件，以毛细管柱色谱柱分析取代原填充柱分析，改进后的分析方法合理、分析结果准确可靠，并大大缩短了分析时间。     

真密度方法的建立及应用

由于质检中心分析抽出油进厂验收密度的方法一直是采用稀释法密度分析,此方法从样品稀释到分析再到换算结果报出分析过程时间较长,分析过程中影响因素较多,中心现有一台真密度仪,用来分析焦炭的密度,经过论证,通过具体研究实验条件,从对仪器的校准、抽出油样品在不同温度下的比对分析及用稀释法密度分析、比重瓶法密度分析,得出结论:抽出油密度可以采用真密度仪进行分析,样品的准确性及重复性均符合标准要求,分析时所需样品用量少,样品室清洗方便,也可减少对环境的污染,可进行抽出油进厂验收密度的日常分析。     

谈谈建立财务分析系统的构想

财务分析是指财务分析者以企业有关会计资料为依据,采用专门的方法,对企业生产经营成果和财务状况进行分析研究的一项管理活动或行为.财务分析主体是指与企业有现存的和潜在的利益关系,并希望通过对企业财务分析而获得企业财务信息的单位或个人.一般来说企业财务分析的主体有企业经营者,企业投资者,企业债权人以及其他与企业经济利益有关系的单位或个人.由于企业财务分析主体的多元性,决定了企业财务分析目标的多元性.     

关于药物液相色谱分析前处理技术的教学研究

药物分析样品前处理技术是可以显著减少测定干扰因素并提高测定结果可靠性的有效方法,特别适用于成分复杂的药物样品分析。结合药物分析案例,概括各类前处理技术及其特点,为药物分析学习者和药物分析科技工作者针对成分复杂的药物样品分析提供药物分析前处理技术创意思路。有力证明了结合样品前处理技术的药物分析实验课程是培育复合型药学人才的重要渠道。     

热分析技术在涂料分析研究中的应用

介绍了近些年来国内外热分析技术在涂料分析研究中的应用进展。阐述了热分析技术在涂料成分和含量分析、固化、老化、热稳定性、热降解等方面的应用,最后展望了热分析技术在涂料分析研究的应用前景。     

影响甲醇酸度分析数据极差的原因分析

通过实验排查出影响酸度分析数据极差的主要因素。通过制定有效措施，降低甲醇酸度分析数据的极差，将分析最大极差由0.000 4%降至0.000 1%,提高分析数据的精密度，从而有利于提高分析数据的准确度，为工艺提供可靠的分析数据，为生产优质的甲醇产品提供保障。     

药物分析课程思政教学实践探索

党的十八大以来，党中央高度重视课程思政，高校教育也形成了从思政课程到课程思政的新热点。药物分析是药学领域的一门重要的专业基础课，本文从药物分析的课程思政教学入手，分析本学院药物分析课程特点，阐述了药物分析课程开展思政教育的重要性，对药物分析课程中的思政元素进行了挖掘，并探索了药物分析课程思政的教学方法。通过对药物分析课程思政的探索，将社会主义核心价值观贯穿药物分析教学始终，以期为国家培养更多合格的社会主义接班人。     

Failure of tannic acid to inhibit digestion or reduce digestibility of plant protein in gut fluids of insect herbivores

The rate of hydrolysis of the abundant foliar protein, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC), in enzymatically active gut fluid ofManduca sexta larvae is very rapid and is unaffected by the presence of tannic acid, even when tannic acid is present in the incubation mixture in amounts in excess of the amount of RuBPC. When this protein is dissolved in the denatured gut fluids ofM. sexta larvae orSchistocerca gregaria nymphs, large amounts of tannic acid must be added to bring about the precipitation of significant quantities of protein. The ability of insect gut fluid to prevent the formation of insoluble tannin-protein complexes is due to the presence of surfactants. On the basis of our results and a review of the findings of other investigators, we argue that there is no evidence that tannins reduce the nutritional value of an insect's food by inhibiting digestive enzymes or by reducing the digestibility of ingested proteins and, further, that the failure of tannins to interfere with digestion is readily explained on the basis of well-documented characteristics of the digestive systems of herbivorous insects. In challenging the currently popular notion that tannins are digestibility-reducing substances, we do not challenge the general utility of either the apparency theory or resource availability theory of plant defense. In debating the merits of these two analyses of plant-herbivore interactions, however, the demise of tannins as all-purpose, dose-dependent, digestibility-reducing defensive substances must be taken into account.     

机制砂岩性与级配对混凝土抗硫酸盐侵蚀性能的影响

为了探究不同岩性、不同级配机制砂对混凝土性能的影响,对三种不同岩性机制砂混凝土及天然河砂混凝土的工作性和抗压强度进行研究。此外,对比分析了四种混凝土在干湿循环制度下的抗硫酸盐侵蚀性能。结果表明,天然河砂混凝土的工作性优于机制砂混凝土,钙质机制砂混凝土的工作性略好于硅质机制砂混凝土。机制砂混凝土的抗压强度优于天然河砂混凝土,在硫酸盐侵蚀循环作用下的力学性能变化趋势与天然河砂混凝土基本一致。在相同级配条件下,机制砂混凝土的抗蚀系数高于天然河砂混凝土;机制砂岩性并不会对混凝土抗硫酸盐侵蚀性能带来负面影响。级配良好的机制砂可以增强混凝土抗压强度和抗硫酸盐侵蚀性能。     

Functional properties of proteins in foods

The measurement of functionality of protein food ingredients has developed somewhat haphazardly, probably due to the wide range of proteins used as ingredients and the diversity of foods. Studies of the physiochemical properties of proteins should enable prediction of a proteins response to process environments and prove more fruitful than many of the empirical measurements of functionality. The effects of pH, salt type and concentration on the phase behaviour of the oilseed globulin and arachin, demonstrates the complexity of protein solubility and the inadequacies of simple tests that have arisen. Studies of the effects of salts and conditioning on meat fibres, coupled with measurement of the location of water in pellets from water holding tests enable the latter to be applied with increased confidence. Comparison of the endothermic transitions observed on heating with the development of storage and loss moduli allow the contributions of domains of skeletal muscle myosin to gel structure to be investigated.     

Aggregation pheromone system of adult gregarious desert locust schistocerca gregaria (forskal)

Six electrophysiologically active aromatic compounds, viz., anisole, benzaldehyde, veratrole, guaiacol, phenylacetonitrile, and phenol, were identified in the volatiles of older-adult male desert locust. Young adults and females of all age groups produced none or only trace quantities of these compounds. Comparison of the aggregation responses of young and older adults to the crude, older-adult, volatile extract and different synthetic blends of the six compounds showed that the aggregation pheromone system of the adult gregarious locust consists of phenylacetonitrile, guaiacol, phenol, and benzaldehyde. Like the crude volatile extract of older males, neither the synthetic blend of the six compounds nor the adult pheromone blend evoked any significant aggregation responses from nymphs. These results confirm our previous report of sexual differentiation in the production of adult aggregation pheromone in the desert locust and of the evidence of two distinct aggregation pheromone systems in the two stages of the insect.     

Molecular mechanics modelling of interfacial energy and flexibility on cellulose

Molecular mechanics modelling is used to calculate the energies of interaction, hence the molecular level energy of adhesion at the interface with crystalline cellulose I of three different photopolymerizable primers and of a polyester varnish at the interface with the primer/cellulose assembly. The energy of interactions for just one of the primers with the statistically most common conformation of amorphous cellulose has also been obtained for comparison. Experimental results of adhesion by a standard peel test and by thermomechanical analysis, in which the effect of viscoelastic energy dissipation by crack tip propagation has been respectively minimized or is not present, hence in which the energy of interfacial interaction is nothing else but the work of adhesion, correlated well with the energies of interaction calculated by molecular mechanics. An equation correlating the energy of interaction at each finish/cellulose interface with the deflection derived by thermomechanical analysis, and with the number of internal bond rotational degrees of freedom as well as the degree of networking of the finish, has been derived and is presented. A relationship between the intrinsic fracture energy Go and the molecular mechanics-derived energy of interaction at the interface equating this to the square of the work of adhesion is obtained and is presented.     

Distribution of birch (Betula SPP.), willow (Salix SPP.), and poplar (Populus SPP.) secondary metabolites and their potential role as chemical defense against herbivores

Isoprenoids and phenolics, major metabolites of important browse species, are reviewed in regard to concentrations, distribution within tissues, and between species. Seasonal variation of specific substances and changes with age of the plant are also considered. The distribution of substances may affect food selection and feeding behavior of animals. Wild mammalian herbivores tend to avoid plant parts rich in these substances, in spite of high nutritional content of the plant tissue. Possible mechanisms for defense by plants against depredation by mammalian herbivores are discussed within the framework of the plants' biochemistry.     

Sr改性Cu催化剂的果糖加氢制备甘露醇性能

使用共沉淀法制备负载Cu催化剂。通过添加碱土金属Sr，对Cu催化剂进行了改性，以提高Cu催化剂在果糖加氢制备甘露醇过程中的活性和选择性。采用ICP-MS、TEM、XRD、H₂-TPR、XPS和CO₂-TPD等对所制备的催化剂进行了系统表征。结果表明：Sr的添加能增大催化剂的比表面积，促进活性组分Cu的分散，从而提高了催化剂的活性，并且增加了催化剂的碱性，使果糖优先形成β-呋喃糖中间体，从而提高了甘露醇的选择性。在果糖浓度为1.1 mol·L^-1、催化剂用量为反应物质量的6%、反应温度为373 K、反应氢压为4.0 MPa、Cu/Sr原子比为7∶1的反应条件下，果糖转化率为99%，甘露醇的选择性为79%。催化剂循环使用了20次，其催化稳定性基本保持不变。     

接触式机械密封界面泄漏机理研究的关键科学问题

密封界面的泄漏机理是机械密封研究与应用的焦点问题之一,涉及泄漏通道表征、粗糙表面的接触力学模型、界面微观形貌变化以及介质流体在泄漏通道中的流动阻力等问题。回顾了近几十年国内外接触式机械密封泄漏通道模型的研究,深入分析了G-W模型、M-B模型和Persson模型3种粗糙表面接触力学模型的贡献和存在的问题,提出了一种基于逾渗理论的泄漏通道新模型;探讨了密封界面的分形参数、泄漏通道的流动阻力以及密封界面的有限尺寸效应对泄漏特性的影响,指出孔隙连通贯穿界面和流体流经贯穿通道的流动阻力小是密封界面产生泄漏的成因,以及泄漏通道的形成和泄漏通道内的流体流动特性是泄漏机理研究的主要方向。     

Measured kinetics of the acid-catalysed hydrolysis of sugar cane bagasse to produce xylose

Experimental trials of the water hydrolysis of bagasse to produce xylose, arabinose and glucose were conducted using a temperature-controlled microwave digester. The experimental variables were temperature, ratio of water mass to bagasse mass, type of bagasse material and reaction time. The pH of the liquid and concentration of dissolved xylose, arabinose and glucose were measured at the completion of each trial. Kinetic modelling of the global rates of formation of monosaccharide products was performed using schemes based on earlier researchers’ models of acid hydrolysis using mineral acids. For the most plentiful product, xylose, the most accurate kinetic model of the global reactions was determined to be two parallel pathways for hydrolysis of xylan to xylose followed by a single pathway for xylose decomposition. The calculated activation energies of the reactions were within the range reported by other researchers for the hydrolysis of a range of lignocellulosic materials using mineral acids.