以影攻影——访香港摄影师陈汉全

对一名摄影师来说,相机的地位非同一般,既是形影不离的亲密伙伴,又是工作中的得力工具,我们在欣赏摄影师多彩纷呈作品的时候,往往不会注意相机这个默默无闻的角色.那么,如果相机变成拍摄对象,昔日低调的工具拭去尘土,站到聚光灯之下,又会是何种情形呢?我们专门请到帮尼康拍了4年多亚太区平面广告的香港摄影师陈汉全(Garry Chan),来听听一个摄影师"以影攻影"的经验之谈.     

THE MEASUREMENTS OF HUMAN INHALABILITY OF ULTRALARGE AEROSOLS IN CALM AIR USING MANNIKINS

An idea was first introduced during the 1970s that particles cannot produce adverse health effect unless they are inhaled into the human respiratory tract. Since then several studies have been carried out to investigate the inhalable fraction of ambient aerosols. However, the previous studies were confined to the conditions of external convective flow and particle aerodynamic diameter smaller than 100 μm. This paper reports the results from an inhalability study for particle aerodynamic diameter for a range of diameters which include diameters greater than 100 μm under a condition of no external convective flow. The concept of mass balance was used in this study to derive an equation for determining the ambient particle concentration from which inhalability was calculated. The results suggested that difference in ventilation demands between adults and children does not affect inhalability, however, the inhaled dose was significantly higher in adults than children because of higher ventilation demand of adults. In terms of the breathing mode, the inhalabilities of oronasal breathing for people at heavy exercise are much higher than those of nasal breathing which simulates breath at rest and moderate exercise. The inhalability curve derived from this study indicated that a cutoff diameter for zero inhalability exists, which should be considered in the future revision of ACGIH inhalable aerosols criteria.     

STUDY OF THE TURBULENT FLOW IN AN UNBAFFLED STIRRED TANK BY DETACHED EDDY SIMULATION

Detached eddy simulation (DES) of the liquid-phase turbulent flow in an unbaffled stirred tank agitated by a six-blade, 45°-pitched blade turbine was performed in this study. The tank wall is cylindrical with no baffle and the fluid flow problem was solved in a single reference frame (SRF) rotating with the impeller. For the purpose of comparison, computation based on large eddy simulation (LES) was also carried out. The commercial code Fluent was used for all simulations. Predictions of the phase-averaged turbulent flow quantities and power consumption were conducted. Results obtained by DES were compared with experimental laser Doppler velocimetry (LDV) data from the literature and with the predictions obtained by LES. It was found that numerical results of mean velocity and turbulent kinetic energy profiles as well as the power consumption are in good agreement with the LDV data. When performed on the same computational grid, which is under-resolved in the sense of LES, DES allows better accuracy than LES in that it works better in the boundary layers on the surface of the impeller and the stirred tank walls. It can be concluded that DES has the potential to predict accurately the turbulent flow in stirred tanks and can be used as an effective tool to study the hydrodynamics in stirred tanks.     

劈离砖隧道窑燃用低压热脏煤气实验研究

就同轴旋转交叉射流燃烧器的冷态流动特性进行实验研究 ,通过测定模拟煤气与助燃空气流量以及压力变化的相互关系研究了燃烧器的抽吸性能 ;在生产现场的低压热脏煤气燃烧实验中 ,考察了燃烧器的预混性能 ,并同轻柴油的燃烧情况进行比较 .结果表明 ,采用同轴旋转交叉射流燃烧器时 ,助燃空气的流量大于一定数值就能对煤气产生强烈抽吸作用 ,并以此增强空气与煤气的混合程度实现低压热脏煤气的洁净燃烧 ,其中燃烧所产生的火焰颜色和透明度均优于轻柴油 ,可以满足彩色环保型劈离砖隧道窑的生产要求     

氢化丁腈橡胶及其加工应用

氢化丁腈橡胶(HNBR)是国外近年来开发成功的一种物理机械性能优异、耐高温、耐臭氧、抗液体腐蚀性能极好的专用弹性体。主要适用于汽车制造、油井、军事及飞机制造等工业领域中。目前世界市场上只有Therban(联邦德国Bayer公司)、Toynal(加拿大Polysar公司)和Zelpol(日本Zeon公司)等几个商品牌号。本文拟以Therban为例,着重对HNBR的基本性能和加工应用性能作一探讨。     

粗细节丝及其织物的开发应用

综述了粗细节丝的生产及应用。介绍了日本各大公司粗细节丝的性能，主要采用的生产技术及其织物的开发应用，特殊粗细节丝现状以及粗细节丝的高次加工。     

元明青花红绿彩的研究与考证

青花红绿彩作为加彩器的一种,比传统的观点早一个朝代,根据明中青花红绿彩盖罐结合最新的窑址考古成果,得出元代的窑炉设计和釉面配方的缺陷,使元代青花红绿彩的生产和存世极少,明官窑中由于斗彩的出现,青花红绿彩在民间一直沿烧。与元代风格相近,只是到了后期风格才大变。     

丙烯腈与丙烯酸的共聚合及表征

以偶氮二异丁腈为引发剂,研究了丙烯腈与丙烯酸在二甲基亚砜中的自由基溶液共聚合反应。考察了单体质量分数,引发剂质量分数、反应温度和时间等对共聚反应的影响。分别用称重法和乌氏粘度计测定了反应的转化率和产物的相对分子质量。用IR,DSC和TG对产物的结构和性能进行了表征。研究结果表明,最佳的反应条件是：总单体质量分数22％,AIBN占总单体质量分数1％,反应温度和时间为60℃和24h。     

国内先进陶瓷状况与发展机遇和挑战

随着现代科学技术的高速发展,迫切要求研制与发展具有特殊性能的新一代先进陶瓷材料.这是因为先进陶瓷具有高强度、高硬度、耐高温、耐腐蚀以及优异的电学性能、光学性能、化学稳定性和生物相容性等优点,从而在航天航空、国防军工、机械化工、生物医疗、信息电子、核电与新能源等领域得到越来越多的应用,已成为国家某些重大工程和尖端技术中不...