DEVELOPMENT OF AN AUTOMATIC SYSTEM FOR COUNTING ASBESTOS FIBERS USING IMAGE PROCESSING

ABSTRACT

Atmospheric concentrations of carcinogenic asbestos fibers, have traditionally been measured visually using phase contrast microscopy. However, because this measurement method requires great skill, and has poor reproducibility and objectivity, the development of automatic counting methods has been long anticipated. We have developed the Asbestos Fibers Automatic Counting System (AFACS), and verified its accuracy via application to illustrations obtained from the Asbestos Internationa) Association (AIA). Important features of the AFACS system are as follows:

(1) Counting criteria of the automatic counting system conform to those of visual counting

(2) The cost of the whole system is low because it is microcomputer-based.     

Enzymatic Maceration of Vegetables with Protopectinases

Protopectinases (PPases) are a heterogeneous group of enzymes that solubilize pectin from the insoluble protopectin in plant tissues by restricted depolymerization. Various PPases have been reported with different pectin solubilizing activities depending on the substrate. We studied the macerating properties of some PPases on potato, carrot, garland chrysanthemum, garlic, ginger, spinach, and red pepper. Crude culture filtrate from Trichosporon penicillatum SNO-3, containing PPase-SE, was most effective for maceration of potatoes, and the PPase-B from Bacillus sub-tilis IF0 12113 was most effective for carrots. Enzyme concentration, pH, reaction time, and rate of shaking affected the yield of single cells.     

22Na次级束的产生与应用

在日本东京大学核研究中心的放射性离子束分离器上,利用逆运动学反应¹H(²²Ne,²²Na)n产生了²²Na次级束。经分离器电磁系统的分离提纯后,获得了能量为（78.3±1.0） MeV的²²Na次级束。实验靶站处次级束的强度达2.5×10⁵ s^-1,其中²²Na的纯度好于90%。²²Na次级束已应用于与核天体物理Ne丰度异常问题相关的²²Na+α共振散射实验研究。     

Metabolites of Eurotium Species, Their Antioxidative Properties and Synergism with Tocopherol

Natural antioxidants and synergists for tocopherol (Toc) have been isolated as acetone or ethyl acetate extracts from mycelial mats or culture broth of Eurotium species. The acetone extract, eluted stepwise with benzene and ethyl acetate by silica gel column chromatography, gave fractions that were synergistic with Toe. However, the benzene fraction appeared better because it was highly soluble in oil and did not change the color and taste of the oil. The metabolites in the benzene fraction differed in the various Eurotium species in their composition in respect to known metabolites with antioxidative activity.     

Delay-independent stabilization of linear systems

Stabilization of delayed linear systems by state-variable feedback is studied in this paper. The assignability of the decaying rate of these systems is also considered. The conditions obtained are applicable to systems with time-varying delays without any restriction. The basis of these conditions is a criterion for delay-independent stability of linear system previously obtained. It is shown that in some cases a system is delay-independent stabilizable although a decaying rate is not assignable for this system.     

Mechanism of Ni-Zn Ferrite Formation in the Presence of Molten Li2SO4-Na2SO4

Nickel-zinc ferrite powder was prepared from the constituent oxides in the presence of molten Li₂SO₄-Na₂SO₄. The effect of ZnO on the reactivity of NiO was studied. The process of Ni-Zn ferrite formation was followed by X-ray diffraction and thermomagnetic analyses. Particle size and shape of the product were determined by scanning electron microscopy. In the presence of molten salt, ZnO enhances the reactivity of NiO, and Ni-Zn-ferrite formation is completed at lower temperature than Ni ferrite formation. In the reaction for the formation of Ni-Zn ferrite, Zn ferrite forms before NiO is incorporated into the ferrite phase. The reaction between the initially formed Zn ferrite and NiO leads to a rate of Ni-Zn ferrite formation higher than that of Ni ferrite formation from NiO and Fe₂O₃.     

接枝量对等离子体接枝聚异丙基丙烯酰胺开关的多孔膜的温度感应透过性的影响

The effect of graft yield on both the thermo-responsive hydraulic permeability and the thermo-respousive diffusional permeability through porous membranes with plasma-grafted poly(N-isopropylacrylamide) (PNIPAM)gates was investigated. Both thermo-respousive flat membranes and core-shell microcapsule membranes with a wide range of graft yield of PNIPAM were prepared using a plasma-graft pore-filling polymerization method. The grafted PNIPAM was formed homogeneously throughout the entire thickness of both the fiat polyethylene membranes andthe microcapsule polyamide membranes. Both the hydraulic permeability and the diffusional permeability were heavily dependent on the PNIPAM graft yield. With increasing the graft yield, the hydraulic permeability (water flux) decreases rapidly at 25℃ because of the decrease of the pore size; however, the water flux at 40℃ increases firstly to a peak because of the increase of hydrophobicity of the pore surface, and then decreases and finally tends to zero because of the pore size becoming smaller and smaller. For the diffusional permeability, the temperature shows different effects on the diffusional permeability coefficients of solutes across the membranes. When the graft yield was low, the diffusional coefficient of solute across the membrane was higher at temperature above the lower critical solution temperature (LCST) than that below the LCST; however, when the graft yield was high, the diffusional coefficient was lower at temperature above the LCST than that below the LCST. It is very important to choose or design a proper graft yield of PNIPAM for obtaining a desired thermo-respousive “on/off“ hydraulic or ditfusional permeability.     

DEFORMATION BEHAVIOR OF γ-TiAl SINGLE CRYSTALS AT DIFFERENT TEMPERATURES

在－１９６－１１００℃温度范围内,利用压缩试验研究了γ－ＴｉＡｌ单晶（Ａｌ的原子分数为５６％）在「００１」,「１５２」,「０２１」,「２３３」,「１９１」,「２５１」,「１１０」七个晶体取向上的塑性变形行为,它们的屈服强度温度关系曲线都可分成三个部分：－１９６－６００℃屈服强度随温度的升高先是快速下降,达到室温附近以后基本保持不变;６００℃以上,屈服强度随温度的升高而反常升高,随晶体取向的不同在７     

Al2O3纤维砂轮的开发及其磨削特性

细磨粒砂轮用于高精度磨削。然而,由于细磨粒具有较小的结合面积和强度,即使在正常的磨削条件下,磨粒易于从砂轮表面上脱落,导致加工精度与效率低下。近年来,由于Al2O3纤维具有优良的机械与物理化学性能如高强度、高弹性模量、耐磨损、耐高温氧化及耐酸、耐碱等,与基质材料具有良好的相容性,因而被广泛地用于FRP、FRC和FRM等的强化材料。A2O33纤维的平均直径和长度分别为3—5μm和数百μm,比相同直径的细磨粒具有较大的结合面积和强度。因此,1998年以来,日本山口胜美、洞口严教授和中国魏源迁教授使用Al2O3纤维替代磨粒作为磨料,与酚醛树脂结合剂结合,成功地开发了一种A12O3纤维砂轮,能克服磨粒砂轮的缺陷。该砂轮中的纤维排列方向与磨削面相垂直,纤维的端部可用作为切削刃,而且纤维砂轮比磨粒砂轮细密,使用纤维砂轮可实现干磨削和纳米加工。为了考察Al2O3纤维砂轮的磨削特性,本文对难加工材料如模具钢SKD11(HRC60)进行了大量的磨削试验,试验结果表明能获得纳米级加工表面(Ra2．1nm／Ry22nm)。