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1.
潘传智 《大学化学》1988,3(1):14-16
本文提出将状态性质的加和性分为三种:部分加和性、组分加和性和基因加和性。这样分类后,容量性质和强度性质的区别与联系更加清晰。凡容量性质必定具有部分加和性,而强度性质必定没有部分加和性。因此,用有无部分加和性来区分状态性质为容量性质和强度性质是最确切的,不易引起误解。部分加和性就是通常说“容量性质在一定条件下有加和性”的那种加和性。  相似文献   

2.
探讨了使用微波灰化技术消化原油和成品油样品,并使用氢化物发生-原子荧光光谱法测定其中铅和砷的含量.研究了铅测定的灰化保护剂和砷测定的灰化助剂,并优化了仪器工作条件和实验条件.该方法测定原油和重油中铅的平均回收率分别为96.8%和96.7%,相对标准偏差分别为1.03%和0.93%;测定原油和重油中砷的平均回收率分别为90.0%和90.3%,相对标准偏差分别为2.39%和2.63%.  相似文献   

3.
研究了加入镧或钇和不加镧钇的QBel.9合金性能差别。采用相同的加工工艺加工的含镧和钇和QBel.9和不含镧和钇的QBel.9合金的样品,然后观察和检测三种合金的质量和性能。  相似文献   

4.
结晶高聚物的结晶度与密度有密切关系,体积结晶度和重量结晶度与聚合物的非晶密度、结晶密度和实际密度之间都存在对应的关系,在一般的教学中,都是利用密度加和性和比容加和性来推导这2个关系公式的,本文以更加简洁易懂的体积加和性和重量加和性非常简单地推导出了这2个关系公式,便于学生掌握和理解。  相似文献   

5.
今年是吉林大学徐如人教授和庞文琴教授执教六十年暨八十华诞.本期<高等学校化学学报>作为特刊,收集了来自徐如人教授和庞文琴教授的学生以及一些同事和合作者的60篇学术论文以及二位德高望重的教授在不同年代的一些工作和生活的照片.这些论文和照片分别以不同的视野和角度记载和诠释了先生们的学术足迹和风貌,也展示了他们过去60年在无机化学教学与科研的辛勤耕耘和杰出贡献.  相似文献   

6.
中药指纹图谱学体系在中药创制中的作用   总被引:3,自引:0,他引:3  
孙国祥  毕开顺 《色谱》2008,26(2):172-179
从整体论、系统论和复杂科学的角度论述了中药指纹图谱学体系的构成背景和核心任务。中药指纹图谱学体系具有体系科学性质,是从系统性和整体性角度研究中药(包括植物药)的物质基础和作用机制以及药代动力学规律和相关制剂技术的崭新学科。该体系以中药指纹图谱信息学为核心和桥梁,包括中药指纹图谱测试学、中药指纹图谱质控学、中药指纹图谱谱效学、中药指纹药物动力学、中药指纹药剂学和中药生物指纹图谱学。该体系的研究需采用复杂科学和体系科学的理论和方法,突破线性思维和还原分析,强调宏观和系统的有机综合,应用数学科学原理和方法来开辟中药创制的新模式。中药指纹图谱学的理论体系和方法是解析中药的主导技术和实现中药现代化的核心力量,该体系理论和技术的成熟及完善可为现代中药创制提供强有力的理论和技术支撑。中药指纹图谱学体系的最终目的是为人类和有益生物研制出疗效显著、安全、可控的现代化中药。  相似文献   

7.
多氯萘的来源及环境污染特征研究   总被引:2,自引:0,他引:2  
多氯萘(PCNs)具有和二口恶英类(PCDD/Fs)相似的结构和毒性,在全球的环境和生物样品中都能被检测到.本文介绍了环境中PCNs的主要来源和环境归宿,重点介绍了焚烧和金属冶炼等过程中PCNs的排放特征,归纳了当前全球环境介质和生物体中PCNs的污染水平和分布特征,对我国多种环境介质和生物体中PCNs污染水平和分布特征的相关研究进行了归纳和讨论.最后提出了PCNs相关研究领域研究进展与面临的挑战.  相似文献   

8.
甲基丙烯酸甲酯聚合动力学和分子量模型及仿真   总被引:2,自引:0,他引:2  
考虑甲基丙烯酸甲酯聚合过程中体积收缩,反应物和生成物的浓度变化,以及由于凝胶、玻璃化和笼闭等效应对各速率常数和物性参数的影响,从基元反应和物料平衡出发,推导了半间歇,有链转移剂参与情况下的聚合动力学和分子量模型。用模型仿真计算了聚合温度、引发剂、溶剂和链转移剂的种类和浓度等对甲基丙烯酸甲酯聚合动力学和聚合过程中分子量变化的影响规律,并与实验和文献数据进行比较。  相似文献   

9.
红外光谱与核磁共振波谱在甲壳素结构研究中的应用   总被引:13,自引:0,他引:13  
本文综述了红外光谱和核磁共振波谱在甲壳素和壳聚糖的乙酰度、衍生物的取代位置和取代度、晶体结构和结晶度以及构型和构象、与离子和其他分子间的相互作用等研究领域的应用状况,引用文献61篇。  相似文献   

10.
用从头算和MP2方法求得亚硝酸甲酯的基态、第一和第二激发态解离为CH3O和NO自由基的解离能分別为238.14、68.99和-183.97kJ/mol,而CH3O和NO易于生成甲醛和硝酰。由CI方法求出的亚硝酸甲酯直接生成甲醛和硝酰的基态和激发态反应曲线表明,该反应难以按这种机理进行。因此,以上计算支持了实验提出的亚硝酸甲酯光反应生成甲醛和硝酰的两种机理中的光解离机制。  相似文献   

11.
In 2014, a new type of the fire-resistant paper based on ultralong hydroxyapatite (HAP) nanowires was reported by the author’s research group, which had superior properties and promising applications in various fields, such as high-temperature resistance, fire retardance, heat insulation, electrical insulation, energy, environmental protection, and biomedicine. The wet end chemical properties of the fire-resistant paper pulp are very important for papermaking and mechanical performance of the paper, which play a guiding role in the practical production of the fire-resistant paper. In this paper, the wet end chemical properties of a new kind of fire-resistant paper pulp based on ultralong HAP nanowires are studied for the first time by focusing on the wet end chemical parameters, the effects of these parameters on the properties such as flocculation, retention, draining, and white water circulation of the fire-resistant paper pulp, and their effects on the properties of the as-prepared fire-resistant paper. The experimental results indicated that the wet end chemical properties of the new kind of fire-resistant paper pulp based on ultralong HAP nanowires were unique and entirely different from those of the traditional paper pulp based on plant fibers. The wet end chemical properties of the fire-resistant paper pulp were significantly influenced by the inorganic adhesive and its content, which affected the runnability of the paper machine and the properties of the as-prepared fire-resistant paper. The flocculation properties of the fire-resistant paper pulp based on ultralong HAP nanowires were affected by the conductivity and Zeta potential. The addition of the inorganic adhesive in the fire-resistant paper pulp based on ultralong HAP nanowires could significantly increase the conductivity of the fire-resistant paper pulp, reduce the particle size of paper pulp floccules, and increase the tensile strength of the fire-resistant paper. In addition, the fire-resistant paper pulp based on ultralong HAP nanowires in the presence of inorganic adhesive exhibited excellent antibacterial performance. This work will contribute to and accelerate the commercialization process and applications of the new type of the fire-resistant paper based on ultralong HAP nanowires.  相似文献   

12.
We propose a unique soft actuator—a paper actuator—based on carbon-nanotube-composite paper (CNT-composite paper), which is a composite of carbon nanotubes (CNTs) and paper. CNT-composite paper has highly efficient properties because of the contained CNTs, such as high electrical conductivity and semiconducting properties. We are considering using CNT-composite paper for various devices. In this study, we successfully developed a paper actuator. We determined the structure of the paper actuator by referencing that of bucky-gel actuators. The actuator operates using the force generated by the movement of ions. In addition to making the paper actuator, we also attempted to improve its performance, using pressure as an index and an electronic scale to measure the pressure. We investigated the optimal dispersant for use in paper actuators, expecting the residual dispersant on the CNT-composite paper to affect the performance differently depending on the type of dispersant. Referring to research on bucky-gel actuators, we also found that the addition of carbon powder to the electrode layers is effective in improving the pressure for paper actuators. We believe that the paper actuator could be used in various situations due to its ease of processing.  相似文献   

13.
During natural ageing, paper undergoes colour changes and becomes brittle. It is mainly due to the degradation of cellulose, the main component of paper fibres. From the viewpoint of conservation/protection of paper-based information carriers, as well as of the utilisation of secondary fibres, knowledge of the impact of a decrease of the degree of polymerisation (DP) of cellulose on mechanical properties of paper becomes of key importance. In this paper, correlations between the decrease of DP of cellulose and the loss of paper folding endurance (FE) using three model samples (pure cellulose, groundwood pulp paper, and degraded groundwood pulp paper) at accelerated ageing were investigated. The existence of such correlations between DP and FE is supported by experimental results; the correlations are linear for pure cellulose and groundwood pulp paper ageing, while exponential correlation was observed in case of degraded groundwood pulp paper. The results indicate that the rate of paper degradation can be evaluated by means of the rate of glycosidic bonds breaking in cellulosic polymer chains both for cellulose and groundwood pulp paper.  相似文献   

14.
The improvement in the tensile strength and water repellency of paper after treatment with a 2-propanol solution of a methyltrimethoxysilane (MTMS) oligomer was studied using filter paper. Titanium butoxide introduced in the solution as a catalyst effectively reacted with the MTMS oligomer, and a Si–O–Ti bond was generated inside the paper. The tensile strength of the paper was remarkably improved by this treatment of impregnation and polymerization of the MTMS oligomer. It was speculated that the reaction proceeded by consuming water that existed among the cellulose fibers by hydrogen bonding, because there was little difference in the tensile strength between the paper treated in air and the paper treated in a dry box. The methoxy groups in the MTMS oligomer demonstrated their good ability of making a three-dimensional network, and at the same time, the methyl groups in the oligomer showed their excellent water repellency. As a result, the treated paper had a good tensile strength even under wet conditions.  相似文献   

15.
Paper industry generates a considerable amount of wastes. Their composition mainly depends on the type of paper produced and the origin of cellulose fibres. Nowadays, in Spain, 40% of solid wastes generated by the paper and pulp industry are deposited directly in landfill, 25% are used in the agriculture, 13% in the ceramic industry and 7% in the concrete production. In the last years, thermal treatment methods like combustion, pyrolysis and gasification have been widely study as alternative techniques for the valorization of different organic waste materials. The main objective of the present work is to study the pyrolysis behaviour of different paper mill waste materials. For this reason, a wide characterization of eight paper mill waste materials from different origins was performed using SEM, FTIR, DRX and thermogravimetric techniques. Paper mill sludges from recycled paper, mainly wastes obtained from deinking process, showed high CaCO3 and clays contents. Compared with the elevated total organic matter content (TOM) of paper mill waste materials their low organic carbon content determined by Cr2O72− oxidation reveals the elevated chemical stability of organic matter, due to high content on cellulose fibres. Analysis of samples by SEM indicates that successive recycled processes of paper leads to paper mill waste materials with more degraded fibres. XRD analyses show as crystalline cellulose was present in reject and primary sludge from paper mills that produced paper from virgin wood. However, crystalline cellulose content significantly decreased in waste materials from recycled paper. Finally, thermogravimetric analysis indicates that presence or mineral matter and degradation of cellulose significantly influences their pyrolysis behaviour. In general, weight loss of paper mill waste materials started at lower temperatures than pure cellulose. In waste materials from recycled paper weight loss continues at temperatures highest than 500 °C due to kaolinite dehydration and carbonates decomposition.  相似文献   

16.
Biodeterioration phenomena represent a complex of physical and chemical alteration processes in various materials, such as those constituting the objects that represent our cultural heritage. The biodegradation of paper is conditioned by several variables such as the materials from which cellulose is obtained, the manufacturing processes employed, the occurrence of other affecting substances such as lignin or metallic compounds, and by the environmental conditions in which papers are conserved. In this study, biodeterioration of paper was artificially induced in order to evaluate the role of a range of chemical and physical variables on damage caused by cellulolytic fungi. A variable pressure SEM instrument was used to characterise paper samples with different fibre origins, and alterations obtained in vitro. Two fungal strains, Aspergillus terreus Thom and Chaetomium globosum Kunze, which are cellulolytic species frequently associated with paper spoilage, were used to produce stains with characteristics close to those observable on art objects made from paper. The stains obtained on the different samples of paper were compared at both low and high magnification, in order to visualize the macro- and microscopic characteristics of paper fibres, inorganic constituents, impurities, and the deteriorating agents related to the spoiled areas. During this survey it was observed that single paper characteristics can strongly influence the intensity and the results of the fungal action. For example, the activity of a fungal strain on paper grades containing fibres of the same origin, but with different sizing, led to the formation of profoundly different stains and alterations. Moreover fungal structures, analysed by low vacuum SEM, in areas on paper corresponding to the stains appeared in different physiological states suggesting an important effect of paper constituents on fungal growth and their sporulating ability.  相似文献   

17.
The review summarizes the use of ligninolytic enzymes in bleaching processes in paper industries. The awareness of society regarding pollution problems demands an effort to develop novel and less polluting processes for paper production. In this regard, there is an emerging interest in various applications of microbes and enzymes. Previously, appropriate enzymes were unavailable, apart from partial use in modification of starch for application in paper coatings. Continued exploration has led to the improvement in enzymes that offer remarkable profits to paper industries.  相似文献   

18.
《Electroanalysis》2017,29(11):2628-2637
This paper demonstrates, for the first time, the use of paper‐based electrochemical devices coupled to external solid working electrodes. The paper‐based electrochemical cells were fabricated using inexpensive and largely available office paper, according to a simple protocol that consists on the creation of hydrophobic barriers using paraffinized paper and preheated metal stamp. The counter and reference electrodes were integrated to the paper platform through the deposition of carbon and silver inks, respectively. The electrochemical paper analytical device (ePAD) was coupled to external glassy carbon rod electrode modified with reduced graphene oxide doped with Cu nanoparticles through meniscus configuration. The analytical usefulness of this electrochemical approach was demonstrated through the simultaneous determination of paracetamol and caffeine in biological samples. The analytes were successfully quantified in real urine samples and limits of detection of 24.6 nM (paracetamol) and 36.1 nM (caffeine) were obtained. The paper platform showed good stability (RSD of 1.07 % for the peak currents and 1.43 % for the peak potentials) and satisfactory performance. The use of solid electrodes coupled to paper electrochemical devices, firstly demonstrated here, opens new possibilities for the utilization of ePADs in electrochemistry and electroanalytical chemistry and offers advantages such as the extremely reduced consumption of reagents and the minimal generation of wastes.  相似文献   

19.
以制浆造纸产业为平台的生物炼制新模式   总被引:10,自引:0,他引:10  
本文通过分析木质生物质炼制与制浆造纸工业之间的关系,提出以制浆造纸产业为平台的生物炼制模式。在蒸煮制浆前,增加对原料预抽提处理,提取半纤维素等成分用于生产乙醇燃料和(或)其他化工化学品,抽提残渣则采用传统化学法、高得率法或有机溶剂法制浆,实现植物纤维原料多组分分离综合利用。该模式给制浆造纸产业提供一条可持续发展的新思路。  相似文献   

20.
There is current interest in using agro-based biopolymers in industrial applications. Because cottonseed protein is abundantly available, it would be useful to explore its feasibility as a polymeric additive and possible substitute for petroleum-based materials. In this work, we studied cottonseed protein isolate as a paper additive and observed its effects on the paper’s dry and wet strength. The tensile strength of paper was found to vary with the amount of the protein applied. By application of an 11% protein solution to the paper, the dry and wet strength increased by 33 and 16% compared with the paper by itself, respectively. The combined use of cottonseed protein and an acid (acetic, adipic, aspartic, and citric acids) to promote adhesion resulted in even greater dry paper strength but not in greater wet paper strength. Thermogravimetric analysis, infrared spectroscopy, and scanning electron microscopic studies suggested that the protein interacted with acid and that both components interacted with paper fibers to produce increased strength.  相似文献   

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