却顾所来径——传统气质、审美文化与当代油画

油画在当代艺术世界中所面临的问题表面上来看是技术层面的,但同时也是精神层面的。当下,油画相较其他形式已经并非最新和最优越的媒材,它的鲜活性和先锋的动能从现代主义开始衰减,从前卫思想的武器库化作了保守者的阵营;在中国,'85的战场已变成了体制的温床后,油画从精神的载体重新回到写实的阵地。在西方的影响已经成为主流、西方艺术的观念成为艺术观念的代称之时,重视油画传统的可能性才再次具备了前卫的意义。

Schlieren Visualization of M arangoni Effect in Gas-Liquid Systems

This paper is focused on the Marangoni effect in the gas-liquid mass transfer systems. A series of experiments were conducted to observe Marangoni effect by a laser Schlieren system. Experimental investigations of the occurrence of Marangoni convection were presented. The typical polygonal patterns and even the reaching of chaotic interfacial flow were observed. The visual evidences were discussed and the characteristic time and scale of Marangoni convection were obtained approximately as 0. 5 s and 1 mm according to the Schlieren images. From the perspective of hydrodynamic instability, the mechanism of the Marangoni convection was investigated. Though many external factors have influence on the interfacial instability, the local surface-tension gradient is the primary reason for the Marangoni convection. The small-scale interfacial flow increases the surface renewal rate. Consequently. due to the occurrence of the Marangoni effect, the mass transfer rate can be significantly enhanced.

Study on the Holdup and Mass Transfer Performances for Gas-Liquid-Liquid System in a Screen Plate Column

The gas and dispersed phase holdups and mass transfer coefficients of liquid-iquid were determined for gas-liquid-liquid three phase system in a screen plate column. The flow pattern of gas-liquid-liquid three phase system was studied under different gas velocities. The shape factors showed the geometric properties of screen plates and the corrected drop characteristic velocities were introduced. The phase holdup in two phases was correlated. The research results indicated that mass transfer coefficient for liquid-liquid system in a column with screen plates and gas agitation was found to increase apparently.

Modeling Hydrothermal Transfer Processes in Permafrost Regions of Qinghai-Tibet Plateau in China

Hydrothermal processes are key components in permafrost dynamics; these processes are integral to global wanning. In this study the coupled heat and mass transfer model for （CoupModel） the soil-plant-atmosphere-system is applied in high-altitude permafrost regions and to model hydrothermal transfer processes in freeze-thaw cycles. Measured meteorological forcing and soil and vegetation properties are used in the CoupModel for the period from January 1, 2009 to December 31, 2012 at the Tanggula observation site in the Qinghai-Tibet Plateau. A 24-h time step is used in the model simulation. The results show that the simulated soil temperature and water content, as well as the frozen depth compare well with the measured data. The coefficient of determination （R2） is 0.97 for the mean soil temperature and 0.73 for the mean soil water content, respectively. The simulated soil heat flux at a depth of 0-20 cm is also consistent with the monitored data. An analysis is performed on the simulated hydrothermal transfer processes from the deep soil layer to the upper one during the freezing and thawing period. At the beginning of the freezing period, the water in the deep soil layer moves upward to the freezing front and releases heat during the freezing process. When the soil layer is completely frozen, there are no vertical water ex- changes between the soil layers, and the heat exchange process is controlled by the vertical soil temperature gradient. During the thaw- ing period, the downward heat process becomes more active due to increased incoming shortwave radiation at the ground surface. The melt water is quickly dissolved in the soil, and the soil water movement only changes in the shallow soil layer. Subsequently, the model was used to provide an evaluation of the potential response of the active layer to different scenarios of initial water content and climate warming at the Tanggula site. The results reveal that the soil water content and the organic layer provide protection against active layer deepening in summer, so climate warming will cause the permafrost active layer to become deeoer and permafrost degradation.

Determination of Absorption Capacity and Mass Transfer Coefficient of Several Oils as Solvents for Biomass Gasification Cleaning System

With the aim to find an absorbing liquid suitable for the gas cleaning system in the application of gasification unit in a remote area, three types of oil were tested using a bubble column and a wetted wall column. Air streams containing toluene vapour with flowrates of 13.6 mL-min1 or 27.6 mL.min^-1 were bubbled through a 50 mL static oil in a glass tube at a temperature of 30 ℃ or 60 ℃. In experiments using the wetted wall column, air streams containing toluene were contacted with a falling thin film ofoil on the outer wall of a column with a diameter of 6.4 cm and two different contacting heights of 60 cm or 80 cm. Toluene concentrations in the air stream were adjusted in the range of 700-3000 ppm corresponding to a typical tars concentration in the producer gas. The phase equilibrium of toluene was represented as values of 1/tl of 326, 220 and 182 respectively for lubrication oil, palm oil and sunflower oil （H is Henry＇s constant with the toluene concentrations in g.L^-1 for liquid phase and g.Nm^-3 for gas phase）. From experiments using the bubble column, it was found that the overall mass transfer coefficient （Kc, a） was in the order of 10.3 cm3-min^-1 and the overall liquid phase mass transfer coefficient （KLa）was about 10.3 cm3.min^-1. Although lubrication oil had a slightly better absorption capacity than the other two tested oils, it had a lower mass trasfer coefficient than that of palm oil. All three proposed oils had a much better absorption capacity and absorption rate than that of water used conventionally as a scrubbing liquid in a small biomass gasification plant.

Relationship between Temperaments of Medicinal Plants and Their Major Chemical Compounds

Objective: To determine any relationship between temperaments of medicinal plants referred to traditional Iranian manuscripts and their major chemical compounds. Methods: Plants used in traditional Iranian medicine were categorized based on their major chemical compounds including alkaloids, phenolic compounds, and essential oils. Their temperaments were extracted from traditional herbal pharmacopeias of Iran. The possible relationship between major chemical compounds and temperaments of each group were evaluated. Results: Plants containing phenolic compounds as their major constituents are hot and dry temperaments except those contain tannins with cold and dry temperaments. Plants containing essential oils have hot and dry temperaments except those whose major essential oils with alcoholic structure which have cold and dry temperaments. Alkaloid-containing plants have cold and dry or hot and dry temperaments based on their alkaloidal structures. Conclusions: There is a close relationship between major chemical compounds of medicinal plants and their temperaments mentioned in traditional Iranian manuscripts.