香港徐泓教授谈明代后期商品经济与社会风气的变迁

应广东省经济史研究会和广东省社会科学院历史研究所的邀请,香港科技大学人文学部部长徐泓教授于1992年11月18日在广东省社会科学院作了题为《明后期商品经济与社会风气的变迁》的学术报告.广州地区各高等院校,科研单位近30位经济史专家参加了报告会.徐泓教授说,明后期是一个矛盾的统—体,一方面,政治黑暗,皇帝昏庸,宦官弄权,特务横行,官场里贪墨成风,社会上物欲横流;另一方面,经济发展却充满活力,蓬勃增长,无论是经济最发达的江南、大运河两岸、长江流域和东南沿海地区,还是比较落后的华北、西北,农业的商品化、专业化与日俱增;国内商业与海外贸易日见繁荣,南北国货与海外洋货充斥国内市场;手工业也很发达,江南等发达地区已出现资本主义萌芽;城镇工商业人口增加,都市化程度较同期的西欧为高.总的看来,明后期的社会经济是高度发展的,当时的繁荣景象,令科学家宋应星感动不已,赞叹“圣明极盛之世也”.

Numerical simulation study of gob air leakage field and gas migration regularity in downlink ventilation

Aiming at the issue that mass of gas emission from mining gob and the gas exceeded in working face, gob air leakage field and gas migration regularity in downlink ventilation was studied. In consideration of the influence of natural wind pressure to analyze the stope face differential pressure, gob air leakage field distribution and gas migration regularity theoretically. Established a two-dimensional physical model with one source and one doab, and applied computational fluid dynamics analysis software Fluent to do numerical simulation, analyzed and contrasted to the areas of gob air leakage on size and gas emission from gob to working face on strength when using the downlink ventilation and uplink ventilation. When applied downward ventilation in stope face, the air leakage field of gob nearly working face, and the air leakage intensity were smaller than uplink, this can effectively reduce the gas emission from gob to working face; when used downlink ventilation, the air leakage airflow carry the lower amount of gas to doab than uplink ventilation, and more easily to mix the gas, reduced the possibility of gas accumulation in upper comer and the stratified flows, it can provide protection to mine with safe and effective production.

Impacts of Wave and Current on Drag Coefficient and Wind Stress over the Tropical and Northern Pacific

By taking into consideration the effects of ocean surface wave-induced Stokes drift velocity Un, and current velocity Uc on the drag coefficient, the spatial distributions of drag coefficient and wind stress in 2004 are computed over the tropical and northern Pacific using an empirical drag coefficient parameterization formula based on wave steepness and wind speed. The global ocean current field is generated from the Hybrid Coordinate Ocean Model （HYCOM） and the wave data are generated from Wavewatch Ill （WW3）. The spatial variability of the drag coefficient and wind stress is analyzed. Preliminary results indicate that the ocean surface Stokes drift velocity and current velocity exert an important influence on the wind stress. The results also show that consideration of the effects of the ocean surface Stokes drift velocity and current velocity on the wind stress can significantly improve the modeling of ocean circulation and air-sea interaction processes.

AN INVESTIGATION INTO TROPICAL CYCLONE MOVING DIRECTION PREDICTION BASED ON OLR DATA

An objective technique of tropical cyclone （TC） moving direction prediction over the Northwestern Pacific Ocean during 2001 - 2002 is studied using GMS-50uting-Longwave Radiation （OLR）data. Three formulae used to predict TC moving direction in 6, 12 and 24 h, respectively, have been obtained based on a multiple linear regression framework and some regression factors including several kinds of OLR characteristic values and the minimum sea level pressure of tropical cyclone center. The multiple correlation coefficients of the statistical analysis using the information of TCs in the Yearbook on Tropical Cyclones to validate the satellite-based prediction are 0.954, 0.945 and 0.914 respectively. The results are satisfying through checking one of the TCs in 2001.The techniques could be applied in future operation and would contribute to TC movement prediction, especially to a sudden change in TC moving direction and improving the forecasting and warning capability.

Aerodynamic characteristics of moving vehicles of two trains passing each other on bridge under crosswinds

Two trains passing each other is controlling factor for the wind-vehicle-bridge systems.To test the aerodynamic characteristics of moving vehicles under crosswinds when two trains are passing each other,a wind tunnel test device,which has two moving tracks,was developed.The rationality of the test result was discussed,the effects of intersection mode,yaw angle and lane spacing on the aerodynamic coefficients of the leeward train were analyzed,and the difference of aerodynamic coefficients between the head vehicle and the tail vehicle was discussed.The results show that the proposed test device has good repeatability.The intersection modes have a certain effect on the aerodynamic force of the leeward train when two trains are passing each other,and the results should be more reasonable during the two trains dynamic passing each other.With the decrease of yaw angle,the sudden change of train aerodynamic coefficients is more obvious.The decrease of lane spacing will increase the sudden change of leeward vehicles.In the process of two trains passing each other,the aerodynamic coefficients of the head vehicle and tail vehicle are significantly different,so the coupling vibration analysis of wind-vehicle-bridge system should be considered separately.

FACTORS AFFECTING THE TRACK OF TROPICAL CYCLONES AFTER LANDFALL IN EASTERN CHINA

The correlation and composite analysis are carried out in this paper to study major factors affecting the track of tropical cyclones (TCs) after their landfall in the east of China. The mid-tropospheric environmental steering flow is found to dominate the movement of a TC even after landfall, with the inertia and Coriolis force two other subordinates. A key region is discovered covering the east of China and Yellow Sea, in which the environmental flow significantly affects the movement of TCs making landfall in this part of China. When the subtropical high in this region strengthens and extends westward, accompanied by northward shrink of the westerly trough, the TC tends to move westward after landfall and disappear inland. However, when the subtropical high in this region weakens and shrinks eastward, accompanied by southward push of the westerly trough, the TC tends to recurve after landfall and re-enter the sea at a location to the north of the site of landfall. The environment before the landfall of a TC has little impact on its post-landfall track, which is sensitive to the environmental change 12 – 24 hours after landfall. A 6-hour lag is found between the environmental change and the movement of a TC after landfall.

我坐了木船

我坐了木船叶圣陶从重庆到汉口，我坐了木船。木船危险，当然知道。一路上数不尽的滩，礁石随处都是，要出事，随时可以出。还有盗匪①——实在是最可怜的同胞，他们种地没得吃，有力气没处出卖，当了兵经常饿肚皮，无奈何只好出此下策②。——假如遇见了，把铺盖或者身上...

也谈“错字及其他”

读《民主》月刊今年第6期上齐灏同志《错字及其他》一文,深有同感。书、报、刊及各种传媒、载体上错字及其他知识性错误空前泛滥,看来已成为社会主义精神文明建设上一大疵点,且有传染蔓延之势,正像电视广告上说的:“不治可不行!”齐文从高层次——人民大会堂,某“大报”及中央电视台栏目中举例,我想要转移风气,治此“顽症”,也必须如此“高屋建瓴”才行。