造纸湿部Zeta电位的测量及应用

详细论述了造纸湿部化学最重要的参数之一Zeta电位的定义、测量方法及在线Zeta电位测量的研究进展。对Zeta电位对微粒系统的影响也进行了讨论     

胶体滴定和Zeta电位在造纸中的应用

用胶体滴定的方法进行聚合物电荷的测定，用Zeta电位仪测定浆料的Zeta电位，探讨了Zeta电位对填料留着率，纸页强度的影响，试验表明；胶体滴定是一种简单，快速，准确的测定高分子聚合物电荷的方法；控制Zeta电位对造纸过程的优化非常重要。     

造纸废水Zeta电位在线测量装置的研究

对造纸废水Zeta电位的测量装置进行了研究。利用流动电位原理,使造纸废水流经管状多孔膜,测出不同压力差下的流动电位,并根据经典的Helmholtz-Smoluchowski方程,可以在线测量造纸废水的Zeta电位。将该设备测定的Zeta电位与离线设备测定结果进行比较。结果表明,该装置能实时地反映出造纸废水Zeta电位的变化。     

胶体滴定和Zeta电位在造纸中的应用

用胶体滴定的方法进行聚合物电荷的测定，用Zeta电位仪测定浆料的Zeta电位，探讨了Zeta电位对填料留着率、纸页强度的影响。试验表明：胶体滴定是一种简单、快速、准确的测定高分子聚合物电荷的方法；对Zeta电位进行控制对造纸过程的优化非常重要。     

改性重质碳酸钙的Zeta电位对加填纸性能的影响

通过控制淀粉改性过程中硬脂酸钠的用量制得不同Zeta电位的改性碳酸钙(GCC),探讨改性GCC的Zeta电位对填料留着率和纸张物理强度的影响。试验结果表明:助留剂CPAM的用量一定,当改性GCC的Zeta电位为-2.89 mV时,留着率达到最大;当改性GCC的Zeta电位为-5.91 mV时,加填纸的抗张强度、撕裂度和耐破度均最大。     

浅述纸料胶体体系中的双电层

综述了纸料胶体体系中双电层的组成、固液表面存在的三种电势 ,ζ电位的测量方法以及添加造纸助剂对双电层的影响。     

麦草浆AKD中性造纸湿部纸料电荷特性研究

对漂白麦草浆的羧基含量和Zeta电位进行了研究,结果表明：在pH值70时,漂白麦草浆的羧基含量为93mmol／100g,Zeta电位23．1mV,羧基含量和Zeta电位绝对值都比木浆高得多。实验也对中性造纸系统中的阳离子淀粉、AKD施胶剂、C-PMA助留剂和GCC填料的电荷特性进行了调查。     

Zeta电位在造纸过程中的应用

控制Zeta电位和pH对于提高造纸过程的效率,改善纸的质量,降低废液的危害有很大的作用。其成就尚在逐步扩大。 1.什么是Zeta电位 纸机湿部胶体粒子的相互作用主要是受它们的Zeta电位的影响。Zeta电位代表一种正的或负的动电荷,以毫伏表示。这种动     

聚乙烯亚胺对阴离子干扰物的化学控制及对纸料湿部性能的影响

造纸湿部系统中溶解与胶体物质(Dissolved and Colloidal Substances,简称DCS)以及无机电解质积累所引起的黏性干扰物问题对造纸生产具有严重影响。选用低分子质量、高阳电荷密度的聚乙烯亚胺(Polyethylenimine,简称PEI)固着剂控制纸料中的DCS,探究不同Ca~(2+)浓度及PEI用量条件下DCS的固着效果,并探讨其对纸料湿部性能的影响。结果表明:随着PEI用量提高,DCS的固着效果提高,纸料的Zeta电位绝对值和网下滤液阳离子需求量降低,纸料滤水速度略有提升;当纸料中存在Ca~(2+)时,Ca~(2+)会屏蔽纤维及DCS模拟物表面负电荷,影响PEI对DCS的固着效果,但可提升纸料的滤水性能。     

造纸法再造烟叶纸机湿部环境初探

利用Zeta电位仪和PCD颗粒电荷测定仪,对造纸法再造烟叶的浆料流送系统及湿部的Zeta电位和阴离子垃圾含量进行检测。结果表明,在一个生产周期内,流浆箱内浆料的Zeta电位平均值为-7.06 mV,阳离子需求量平均值高达970μmol/L,浆料中阴离子垃圾主要来自浓白水。     

不同保守力势能函数的计算及讨论

对重力势能、弹性势能、静电势能等常见的保守力势能所对应的函数进行了计算与讨论，认为势能零点及坐标原点的选取不影响两点间功的计算，但影响计算的繁简程序，因而应尽量选取默认的势能零点及坐标原点。因需要而改变坐标原点或势能零点时，仍需使用势能的一般计算表达式。     

Rheology and baking potential of wheat/plantain composite flour

The possibilty of producing bread from wheat/plantain composite flour has been comprehensively assessed. The chemical analysis of the composite flour showed that it contained less protein and higher carbohydrate and minerals than wheat flour. With increasing levels of supplementation with plantain the water absorption capacity and dough development time of the composite flour decreased. However, the mixing tolerance time increased and the mixing quality decreased. It was found that the baking quality decreased with increasing level of supplementation and when unblanched plantain flour was used. The blend with 100 g kg^?1 blanched plantain and 900 g kg^?1 wheat flour was found to be internally and externally better than other blends and the bread was of acceptable quality.     

Measurement of the oxidation-reduction potential of cheddar cheese

ABSTRACT:  The objective of this study was to develop a method to measure the oxidation–reduction (redox) potential of hard cheeses such as cheddar and to investigate the impact on this parameter of measurement temperature, and factors associated with electrochemical cell design such as distance between reference and working electrodes and depth into the cheese of the platinum electrodes. For this purpose, a novel, self-sealing, platinum working electrode was constructed which was thin and flexible enough to be inserted directly into the cheese sample. A calomel electrode was used as the reference electrode and the circuit was completed with a 3 M KCl salt bridge. The physical orientation of electrodes, such as distance between reference electrode and working electrode, had a substantial effect on equilibrium time for redox potential measurement. The time required for redox potential to reach equilibrium was 2 d in cheddar cheese and the optimum distance between the platinum and calomel electrodes was 2.5 cm. The fastest equilibration time was obtained when the working electrode was inserted 5 or 6 cm into the cheese. Temperature also had an important effect on redox potential. The shortest time to reach equilibrium of potential was at room temperature (20 °C), but it was not practical to keep cheese at this temperature for a period of 2 d. Therefore, redox measurement at 12 °C was recommended in spite of the longer equilibration time compared with room temperature. The results of this study suggest that the novel platinum working electrode allows reproducible measurement of the oxidation–reduction potential of cheddar cheese.     

Anti-irritant potential of cosmetic raw materials and formulations

The investigation studied the anti-irritant potential of several substances commonly employed in cosmetic formulations as basic components of the emulsion or as active ingredients, and evaluated the effect of the emulsifier. Five different emulsions were made irritating by addition of croton oil, in sufficient quantity to provoke a clearly adverse reaction in the rabbit, i.e. primary cutaneous irritation index (PII) close to 2. The PII was determined according to the official French methods by applying to symmetrical areas of the back, the irritant base as control and the same base containing the test substance. Fifty-five ingredients were evaluated: gelling agents, plant extracts, molecules defined as healing, anti-inflammatory substances or anaesthesic compounds, etc. The test substances were added to the emulsion at concentrations close to the ones generally found in cosmetics. The qualitative and the quantitative composition of the oil phase was similar for each emulsion.
Several gelling agents, thickeners and polymers which notably reduce skin contact with an irritant, gave good results. Some of the usual healing, anti-inflammatory, local anaesthesic compounds gave the expected results. Some ingredients, though well known, were ineffective. The type of emulsifier, by modifying cutaneous penetration and bio-availability of the active ingredients, may play an important role.
Le potential anti-irritant de constituants de base et compositions cosmétiques     

我国油脂压榨业开发潜力及应对措施

在查阅近几年来我国油脂压榨业相关资料的基础上,结合对国内外生产实际的考察,明确地提出在加入WTO后对油脂压榨业带来的正面与负面影响效应,指出调整、改革和重组是我国油脂压榨业面临的战略性选择,相适应地提出油脂压榨业其产品开发、技术创新、企业管理与产业建设的具体任务.只有这样,才能达标并与国际接轨,强化油脂压榨业的自我策划、自我改造、自我完善和自我发展的能力,建设有中国特色的油脂压榨产业.     

食用香精的呈味特征结构与潜在危害性分析

食用香精作为一种影响食品口感和风味的特殊高倍浓缩添加剂已经被应用到现代食品工业的各个领域。受天然香料来源、数量、成本的限制,在食品工业中使用的基本都是合成香精、反应香精及天然等同香精。文章对近些年食品香精香味与呈味物质分子结构的关系进行了归纳,并对几种常用香精类型的潜在性危害研究进行了综述。     

"电位活化"现象与金属电沉积初始过程研究简报

针对无氰电镀在镀层结合强度方面还存在的一些问题,用"电位活化"概念给出了理论解释,并从宏观到微观多方位地揭示了电位活化现象的电化学本质:恒电流法电位-时间曲线显示出了金属电沉积初始过程的电位活化平阶和特点;Ar 离子纵向深度溅射与X射线光电子能谱分析(XPS)相结合证实了电镀层结合强度差的原因是电沉积初始过程中镀层/基体界面氧化层的存在.保证电镀层与金属基体良好结合的前提,即实现电位活化的条件是电镀液中金属离子的还原电位必须负于基体金属表面氧化层的活化电位.同时给出了结合强度可与氰化物电镀相近的铁基体上焦磷酸盐直接镀铜工艺.研究表明,镍电极上的电位活化问题也取得了与上述研究一致的结论.     

Burgundy red wines: Representation of potential for aging

This study was conducted to investigate wine professionals’ perception of aging potential of red wines. In the first experiment, 41 wine professionals assessed sixteen commercial Burgundy red wines via a binary categorization task, an aging potential rating task, and a hedonic rating task and an analytic sensory evaluation including an astringency and a bitterness rating task. The wines were also analyzed by High-Pressure Liquid Chromatography with a UV Detector (HPLC-UV) and their color was evaluated using Hue (H*), Lightness (L*) and Chroma (C*) measurements. Results showed that the wines were split into two clusters on the basis of aging potential judgements indicating that the wine professionals had a collective representation of the characteristics of a wine with a potential for aging. Wines with a potential for aging were characterized by low L* and H* and high C* values, a high astringency and a higher concentration of anthocyanins and polyphenol. In a second experiment, 34 wine professionals performed three potential for aging binary sorting task based on (1) visual assessment only, (2) olfacto-gustatory assessment only and (3) overall assessment (visual plus in-mouth). Results showed that the sensory modalities tested were complementary and that visual or olfacto-gustatory assessments alone were not sufficient to explain overall judgments of aging potential.     

关于解析势能函数的研究

利用一种带相位因子的场方程,给出了适用于双原子分子或分子离子间相互作用的解析势能函数,通过调节相位因子可获得多种常见形态的势能曲线.利用该势能函数,计算给出了He2 分子离子电子基态X2Σ 6、LiH分子电子基态X′Σ 、N2分子电子激发态A3Σu 、Cu2分子、Cu2-分子离子等10多种双原子分子或分子离子的势能曲线,结果在较高的精度范围内与实验曲线相一致;同时计算出了H2分子和H2 分子离子的力常数,与实验测定值符合很好;其次,利用该势能函数给出了由微观参量表示的5种固体材料的杨氏模量的解析计算式.