大孔树脂D380固定化橄榄绿链霉菌E-86来源木聚糖酶的研究

选择有代表性的 1 4种吸附和离子交换树脂进行了橄榄绿链霉菌E 86来源的木聚糖酶固定化试验 ,筛选出固定化效果较好的 72 4和D3 80两种树脂 ;对含伯氨基的离子交换树脂D3 80采用戊二醛进行交联固定化 ,研究了其固定化条件。结果表明 ,戊二醛浓度为1 % ,处理 3 0min ,加酶量为 0 8～ 1mL ,酶液pH 5 8,2 5℃ ,5～ 1 0h固定化处理效果最好 ,获得的固定化酶活力可达 64U/ g(载体 )。     

Shock response analysis on thermal stick–slip phenomenon in hard disk drive

We measured and calculated shock responses due to the thermal stick–slip phenomenon in hard disk drives. We first measured the stress wave propagation and found that a stress wave travels over the entire top cover of the drive in 30?μs at two velocities: 4.66 and 2.97?km/s. These are the velocities of longitudinal and distortional waves in a plate, respectively. The position error signal responded in 55?μs after the thermal stick–slip phenomenon happened. We then conducted a numerical analysis of wave propagation. The resultant stress wave propagation and the position error corresponded well to the measured ones. We found that the propagation path which leads overwriting on adjacent tracks is through the actuator to the head, not through the spindle motor to the disk. We concluded that stress waves can be detected with a shock sensor before they arrive at the head if the sensor is located at the pivot bearing or the actuator, which are on the propagation path.     

Minimal design for human–agent communication

Robots have been envisaged as both workers and partners of humans from the earliest period in their history. Therefore, robots should become artificial entities that can socially interact with human beings in social communities. Recent advances in technology have added various functions to robots. The development of actuators and grippers show us infinite possibilities for factory automation, and robots can now walk and perform very smoothly. All of these functions have been developed as solutions for improving robot movement and performance. However, there are many remaining problems in the communication between robots and humans. Communication robots provide one approach to the realization of embodied interfaces. Furthermore, the unsolved problems of human–robot communication can be clarified by adopting the concept of subtractive methods. In this article, we consider the minimal design of robots from the viewpoint of designing communication. By minimal design, we mean eliminating the nonessential portions and keeping only the most fundamental functions. We expect that the simple and clean nature of minimally designed objects will allow humans to interact with these robots without becoming uninterested too quickly. By exploiting the fact that humans have “a natural dislike for the absence of reasoning,” artificial entities built according to minimal design principles can extract the human drive to relate with others. We propose a method of designing a robot that has “character” and is situated in a social context from the viewpoint of minimal design. This work was presented in part at the 10th International Symposium on Artificial Life and Robotics, Oita, Japan, February 4–6, 2005     

High-aspect-ratio through-hole array microfabricated in a PMMA plate for monodisperse emulsion production

Microchannel (MC) emulsification is a promising technique for producing monodisperse emulsions consisting of highly uniform droplets. The authors developed a high-aspect-ratio microstructure (HARMST) made of poly(methyl methacrylate) (PMMA) as a new MC emulsification device. A PMMA straight-through MC array plate consisting of 31,250 through-holes with a 7.3 × 22.9-μm oblong section and a 200-μm depth was fabricated by a process of synchrotron radiation (SR) lithography and etching. Oblong MCs fabricated in a PMMA straight-through MC array were highly uniform with a coefficient of variation of less than 2%. The fabricated PMMA straight-through MC array plate was used to produce water-in-oil (W/O) emulsions. Monodisperse W/O emulsions with average droplet diameters of approximately 25 μm and a minimum coefficient of variation of 3.2% were produced via a hydrophobic PMMA straight-through MC array. The PMMA straight-through MC array plate also produced monodisperse W/O emulsions at droplet production rates of up to 1.7 × 10⁴/s. The PMMA straight-through MC array plates developed in this work are expected to expand the application field of emulsification using straight-through MC array plates, which have previously been made of single-crystal silicon.     

Solid electrolyte of tantalum oxide thin film deposited by reactive DC and RF magnetron sputtering for all-solid-state switchable mirror glass

All-solid-state switchable mirror glass was prepared by magnetron sputtering. The device exhibited the multi-layer structure of Mg₄Ni/Pd/Ta₂O₅ on WO₃/ITO/glass substrate. The Mg₄Ni, Pd, and Ta₂O₅ in the device acted as optical switches, proton injector and solid electrolyte, respectively. Reactive DC magnetron sputtering was employed as a new deposition method for Ta₂O₅ electrolyte thin film for the device. The transmittance of the device, at a wavelength of 670 nm using reactive DC-sputtered Ta₂O₅ thin film, reached 0.1% (a reflective state) to 48% (a transparent state). The transmittance change occurred in less than 40 s when 5 V was applied, and the switching speed was 60 times faster than that of the device using reactive RF-sputtered Ta₂O₅ thin film.     

Reduction of nitric oxide with activated PAN fibres

The reductive removal of nitric oxide from flue gases by reaction with polyacrylonitrile-based active carbon fibres (PAN-ACF) activated with sulphuric acid has been studied at 423–632 K, using a circulating flow reactor. Nitric oxide (0.67 mmol) was completely removed via reduction with 1 g activated carbon under optimum conditions in 210 and 60 min at 423 and 623 K, respectively. N₂ was formed as NO was removed. Some oxygen remained on the carbon surface at 423 K, but was desorbed as CO or CO₂ on subsequent heating to 623 K. The bimolecular reaction of NO reduction over PAN-ACF, and the possible active sites of oxygen surface groups are discussed in the light of a kinetic study and a comparison of the fibre activation at different temperatures.     

Change in Oxygen Content of Y2O3-Nd2O3-Doped Silicon Nitride During Firing

The oxygen content of silicon nitride with 1 mol% Y₂O₃—Nd₂O₃ additive was measured after firing to determine the compositional change during gas-pressure sintering. Oxygen content decreases from 2.5 to 0.94 wt% during firing for 4 h at 1900°C and 10-MPa pressure in N₂. This decrease in oxygen results from the release of SiO gas generated by a thermaldecomposition reaction between Si₃N₄ and SiO₂. The resultant sintered silicon nitride material contains less than 1 wt% oxygen.     

Carbonization of aromatic hydrocarbons—V: Microscopic features of carbons obtained by the aid of catalysts

Microscopic observation of carbons obtained from pure aromatic hydrocarbons by the aid of carbonization catalysts was carried out to clarify the microstructure of these carbons of different features. Reflected polarized-light microscopy distinguished needle, mosaic and isotropic cokes, former two of which were produced with aluminum chloride and the last with potassium. High resolution microscopy revealed that these carbons calcined at 1250° had different degree of layered structure, corresponding to the crystallographic parameters of these samples graphitized at 2500°C. The reasons for the carbons produced with potassium to be non-graphitizable are discussed from the macro- and micro-features of the carbons.     

Modifying carbonization properties of pitches. 3. Carbonization of modified quinoline-insoluble matter from pitches

The carbonization of solubilized matter obtained from the hydrogenated and reductively alkylated quinoline-insolubles of pitches was studied to clarify the different carbonization properties shown by these materials. Dehydrogenation of hydrogenated QI started at 200 °C but continued until 400 °C, passing through a fused phase to give graphitizable carbon. In contrast, alkylated QI gave non-graphitizable carbon because it readily reverted to QI by dealkylation below 300 °C, before fusion. QI alkylated with butyl or benzyl groups was found to be nearly 80% soluble in benzene.     

Radiation-induced polymerization of ethylene in a pilot plant. I. Bulk process

Radiation-induced bulk polymerization of ethylene was carried out with use of a pilot plant with a 10 liter reactor at pressures of 225–400 kg/cm², temperatures of 30–95°C, ethylene feed rates of 5–28 kg/hr, and dose rate of 3.8 × 10⁵ rad/hr. Characteristics of the process are mild polymerization conditions and capability of producing medium density polyethylene in powder form. The spacetime yield and molecular weight of polymer were in the range of 3.5 to 13.1 g/liter hr and 2.2 × 10⁴ to 14 × 10⁴, respectively. The space-time yield increased with mean residence time and 2.4 powders of pressure, and decreased with temperature. Molecular weight changed similarly with the reaction conditions. These results were consistent with those of the bench plant experiment and the scale effect was small. Polymer deposit to the reactor wall limited a period of continuous operation of the plant. The amount of deposited polymer was increased with the square of reaction time. The rate of polymer deposit was proportional to polymer concentration and to the cube of pressure. The polymer deposit cannot be solved in the bulk process.