应用状态方程预测液-蜡(固)相平衡

本文建立了基于状态方程描述重烃混合物液-蜡(固)相平衡的热力学模型及计算方法。计算中采用了经改进的Du-Guo三参数立方型状态方程及作者提出的“十”馏分(原油残余馏分)的特性化方法,对文献中的结蜡点温度及液-蜡相平衡数据进行考核的结果表明,本文模型具有较好的预测准确性,可应用于原油及其馏分油输送及加工设备的设计计算。

Hydraulic and mechanical properties of wax-coated sands

Wax-coated sands are a new category of synthetic soils, which are gradually becoming a reliable construction material. Because of their valuable drainage ability and mechanical properties, wax coated sandy soils are specifically applicable to pavement construction of horseracing tracks and sport fields. Although the mechanical and hydraulic properties of these synthetic soils are well-proven, there is still a lack of studies on how the soil samples behave differently when mixing with different wax fractions. Adding the wax affects permeability and compressibility of pure sand. Intensity of influences is a function of weight percentage of wax that has been added, and other physical and environmental factors. The effects of wax content on hydraulic properties(permeability), and mechanical properties(stress strain behavior, compressibility) of sandy soils based on a series of experimental efforts were investigated. Obtained experimental results infer that increasing the amount of wax up to 6% causes an about 50% increase in permeability, mainly because of the significant effect of wax in lowering the friction along with covering and filling the angular parts of particles' surfaces and forming rounded particles. In addition, wax-coated sands show a 20% to 60% decrease in confined compression modulus compared to non wax-coated sands.

Effects of Alcohol and Liquid Paraffin on Development of Early Mouse Embryos in vitro

In culturing early mouse embryos in vitro,liquid paraffin and alcohol exert deleterious influence on the development of embryos. Some of light liquid paraffin produced by Chinese factories have proved harmful for early mouse embryos. As shown by our experiments, the nitronaphthalene contained and the specific gravity of liquid paraffin were not involved in the injurious effects.However,alcohol mingled in medium had harmful effects on the development of embryos. At the 0.1% concentration of alcohol in medium the proportion of embryos developing to blastocysts decreased to 73.9%. When the concentration of alcohol was increased to 0.8%, all embryos ceased developing. In our experiments, CO_2 which contained 0.13% alcohol had no visible effects on the development of embrvos in vitro.

Effect of Biodiesel Soot on Tribological Behavior of Liquid Paraffin

Biodiesel soot （BDS） was collected from the combustion of biodiesel using a self-made soot trap. The effect of BDS on the txibological behavior of liquid paraffin （LP） was investigated using a four-ball txibometer. A rotating viscometer was used to investigate the effect of BDS on the viscosity of LE The morphology, composition, and tribological mechanism of BDS were studied by means of FETEM, XRD, XPS, SEM/EDS, and the 3D laser scanning microscopy. Test results showed that the BDS aggregates were chain-like, and the average diameter of BDS was 35 nm. The BDS existed in the form of graphitic layers and amorphous carbon. The oxygen-containing functional groups in BDS consisted of the （C-O-C） and （C-O-H）. With an increasing BDS content, the dynamic viscosity of LP increased and the maximum non-seizure load increased initially and became stable later. In addition, the average wear scar diameter （AWSD） of LP increased and the average friction coefficient of LP decreased at first and then increased later. The tribological mechanisms could be ascribed to the variation in content of BDS： BDS could act as a friction modifier for a lower friction coefficient in case of low BDS content. However, the BDS aggregates could lead to increase of abrasive wear to influence the lubricating oil film at higher content of BDS, which would reduce the friction reduction ability and wear resistance of LP.

A New Method of Establishing Orthotopic Bladder Transplantable Tumor in Mice

Objective The present study aims to find a convenient, rapid, and stable method to establish bladder tumor in mice. Methods Female Balb/C-nu-nu nude mice （or female T739 mice） were narcotized by sodium pentobarbital at a dosage of 60 mg/ kg. The stylet of the 24# venous retention needles was bent in a 5° to 7° angle at a distance of 15 mm from the needlepoint to form a circle with 2.61 mm to 3.66 mm radius when the stylet is rotated. The pipe casing was lubricated with liquid paraffin, and inserted into the bladder cavity. The drift angle stylet was inserted into the pipe casing slowly, rotated for five times, and then pulled out. A cell 6 suspension （0.1 mL） of approximately lx10 T24 cells （or BTT cells） was then injected imme＆ately. Results A total of 60 T739 mice and 60 Balb/C-nu-nu nude mice were inoculated with BTT cells and T24 cells, respectively. The bladder tumor incidence and the average survival time of the tumor-bearing mice were 100% and （26.69±9.24） d and 100% and （34.59±9.8） d for the T739 mice and Balb/C-nu-nu nude mice, respectively. Conclusions Using the drift angle stylet to injure the mucous membrane of the urinary bladder can establish a stable bladder transplantable tumor model in mice.

Effects of Preparation Parameters on Paraffin Wax Microemulsion

The paraffin wax microemulsion was prepared from fully refined paraffin wax No.58-60 in the presence of a nonionic surfactant and an anionic surfactant.The influence of manufacturing parameters on the particle diameter of paraffin wax microemulsion included the quantity of the emulsifier,the temperature and emulsification time,the stirring speed,the pH value and the auxiliary ingredient(cosurfactant).The test results showed that the temperature of emulsification had little effect on the particle size of paraffin wax microemulsion in a temperature range of 75-85 ℃.Other manufacturing parameters all had a great effect on the particle size of paraffin wax microemulsion.The optimum preparation conditions included:a w(emulsifier) of 6%,an emulsification temperature of 80 ℃,an emulsification time of 40 min,a pH value of about 8,and a stirring speed of 600 r/min,with n-amyl alcohol serving as the co-surfactant.Under these conditions,a translucent and baby blue paraffin wax emulsion was prepared with its particle size equating to 97 nm.

Use of Residual Material in Biobanking： Solidarity, Common Good, and Informed Consent

Biological residual materials can be obtained from surgical activities or from pathological waste material collected for analysis and stored in formalin. This material can be stored in biobanks with the purpose of future research. Formalin-fixed tissue and also formalin-fixed paraffin embedded tissues are not suitable for all kinds of genetic studies on DNA or RNA, as formalin solution is well known for damaging nucleic acids. Therefore, for the purpose of conducting genetic studies, samples should be frozen in order to maintain a good quality of DNA/RNA over time Biobanks, in which waste samples are frozen, are undoubtedly expensive to maintain; however, it could be useful and important to consider their possible implication in particular research, regarding for example the tumor cells growth process, or when the procurement of samples is difficult. Regarding the relationship between informed consent and tissue collection, storage and research, two choices are possible： irreversible or reversible sample anonymization. These procedures involve different approaches and possible solutions that we will seek to define. Also, an important ethical aspect in regard to the role of biobanks is encouraging sample donation. For donors, seeing human sample being kept rather than discarded and seeing them become useful for research highlight the importance of the human body and improve the attitude towards donation. This process might also facilitate the giving of informed consent more trustfully and willingly.

Antifouling Potential of Bacteria Isolated from a Marine Biofilm

Marine microorganisms are a new source of natural antifouling compounds. In this study, two bacterial strains, Kytococcus sedentarius QDG-B506 and Bacillus cereus QDG-B509, were isolated from a marine biofilm and identified. The bacteria fermentation broth could exert inhibitory effects on the growth of Skeletonema costatum and barnacle larvae. A procedure was employed to extract and identify the antifouling compounds. Firstly, a toxicity test was conducted by graduated pH and liquid-liquid extraction to determine the optimal extraction conditions. The best extraction conditions were found to be pH 2 and 100% petroleum ether. The EC50 value of the crude extract of K. sedentarius against the test microalgae was 236.7 ± 14.08 μg mL-1, and that of B. cereus was 290.6 ± 27.11 μg mL-1. Secondly, HLB SPE columns were used to purify the two crude extracts. After purification, the antifouling activities of the two extracts significantly increased: the EC50 of the K. sedentarius extract against the test microalgae was 86.4 ± 3.71 μg mL-1, and that of B. cereus was 92.6 ± 1.47 μg mL-1. These results suggest that the metabolites produced by the two bacterial strains are with high antifouling activities and they should be fatty acid compounds. Lastly, GC-MS was used for the structural elucidation of the compounds. The results show that the antifouling compounds produced by the two bacterial strains are myristic, palmitic and octadecanoic acids.

Improving Stability of Gasoline by Using Ionic Liquid Catalyst

The composition, characteristics and preparation of ionic liquids are presented. The factors influencing the stability of gasoline and the significance of improving gasoline stability are discussed. A novel way to improve the stability of gasoline by using ionic liquid catalyst is developed. The contents of olefin, basic nitrogen and sulfur in gasoline are determined and the optimal experimental conditions for improving gasoline stability are established.The ionic liquid catalyst, which is environmentally friendly, can reduce the olefin content in gasoline, and such process is noted for mild reaction conditions, simple operation, short reaction time, easy recycling of the ionic liquid catalyst and ready separation of products and catalyst.

Simultaneous determination of l-calycanthine, quercetin, and kaempferol in Chimonanthi Nitentis Folium by RP-HPLC

A reversed-phase high-performance liquid chromatography （RP-HPLC） method was established for the simultaneous determination of three major constituents,/-calycanthine, quercetin, and kaempferol, in Chimonanthi Nitentis Folium. The RP-HPLC analysis was carried out using an Agilent HC-C18 （4.6 mm×250 mm, 5 μm） column and a gradient mobile phase consisting of methanol and phosphate buffer （10：90→90：10, v/v） at a flow rate of 1.0 mL/min. The column temperature was 25 ℃ and the detection wavelength was set at 239 nm from 0 to 15 min and 365 nm from 16 to 45 min. All calibration curves showed good linearity （R2〉0.9991） within test ranges. Relative standard deviations of repeated analyses were less than 2.64% （n = 6）, and the recovery of this method was 97.47%-98.26%. The contents of these three analytes were determined for the samples from different harvest times. The results showed that the/-calycanthine content in herbs increases from 99.94 μg/g to 468.0μg/g from April to July, whereas the content of quercetin and kaempferol was higher in April and May than that in June and July, which were consistent with the Chinese traditional medicine＇s use of Chimonanthi Nitentis Folium in Spring. Herein, a simple, rapid and accurate analytical method is presented and successfully applied for the simultaneous quantitative analysis of alkaloids and flavones from Chimonanthus nitens Oliv.

Numerical study on solid–liquid phase change in paraffin as phase change material for battery thermal management

With the large latent heat and low cost, the paraffin has been widely used in battery thermal management(BTM) system to improve the efficiency and cycling life of power battery. The numerical model of paraffin melting in a cavity has been established, and the effects on the solid–liquid phase change process have been investigated for the purpose of enhancing the heat transfer performance of paraffin-based BTM system. The results showed that the location of the heating wall had great effects on the melting process. The paraffin in the cavity melted most quickly when the heating wall located at the bottom. Furthermore, the effects of thermal conductivity and the velocity of the slip wall have been considered. The gradient of liquid fraction increased with the increase in thermal conductivity, and the melting process could be accelerated or delayed by the slip wall with different velocity.