α‐Complementation in an Artificial Genome Replication System in Liposomes

Genome size is considered one of the limiting factors for the replication of primitive life forms. However, the relationship between genome size and replication efficiency has not been tested experimentally. In this study, we examined the effect of genome size on genome replication by using an artificial cell model: a self‐replicating RNA genome encapsulated in a liposome. For the reduced genome size we used α‐complementation of the lacZ gene. We first characterized α‐complementation in the purified translation system and then applied α‐complementation to the genome replication system. The reduction in the genome size together with the addition of ω‐fragment increased the replication efficiency approximately eightfold. This result provides experimental evidence that genome size can be a limiting factor for primitive self‐replication systems; it also implies that this artificial cell model could be a useful experimental model to identify possible mechanisms of genome enlargement.     

Effect of Liposome Size on Internal RNA Replication Coupled with Replicase Translation

Cell membranes inhibit the diffusion of intracellular materials, and compartment size can strongly affect the intracellular biochemical reactions. To assess the effect of the size of microcompartments on intracellular reactions, we constructed a primitive cell model consisting of giant liposomes and a translation‐coupled RNA replication (TcRR) system. The RNA was replicated by Qβ replicase, which was translated from the RNA in giant liposomes encapsulating the cell‐free translation system. A reporter RNA encoding the antisense strand of β‐glucuronidase was introduced into the system to yield a TcRR read‐out (green fluorescence). We demonstrate that TcRR was hardly detectable in larger liposomes (230 fL) but was more effective in smaller (7.7 fL) liposomes. Our experimental and theoretical results show that smaller microcompartments considerably enhance TcRR because the synthesized molecules, such as RNA and replicases, are more concentrated in smaller liposomes.     

基于旋转GAUSS曲面体热源模型的激光焊接热过程的数值模拟

利用旋转GAUSS曲面体新型热源模型,忽略深熔激光焊时小孔对传热的影响,建立了移动激光热源作用下的三维数学模型.采用PHOENICS3.4软件,模拟了SUS304不锈钢深熔激光焊接热过程的温度场和熔池熔合线形状,得到了激光深熔焊接时的温度场分布规律和"钉头"状的熔池形状,数值模拟结果与实验结果基本吻合.     

Dynamic C‐V characteristic for a varactor load connected with a transmission line

Crosstalk is induced by a reflected wave of a load connected with a transmission line. Thus, analysis of the reflected wave is important. The reflected wave generated from a nonlinear load is complicated. In order to estimate the complicated reflected wave, we measured the reflected and incident waves for the nonlinear load and estimated the dynamic C‐V characteristic, which explains the relation between the incident and reflected waves. This paper reports a simple experimental method of extracting reflected waves at a varactor load and presents estimates of the dynamic C‐V characteristic of the load. It is shown that the reflected voltage waves simulated using the dynamic C‐V characteristic agree with the measured results. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(4): 32–38, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20821     

Biodiesel production through transesterification of triolein with various alcohols in an ultrasonic field

The biodiesel production through transesterification of triolein with various alcohols such as methanol, ethanol, propanol, butanol, hexanol, octanol and decanol was investigated at molar ratio 6:1 (alcohol:triolein) and 25 °C in the presence of base catalysts (NaOH and KOH) under ultrasonic irradiation (40 kHz) and mechanical stirring (1800 rot/min) conditions. It was found that the rate of the alkyl ester formation under the ultrasonic irradiation condition was higher than that under the stirring condition. In addition, it was confirmed that the rate depended upon the kind of alcohols; as the number of carbon in alcohol increased, the rate of the ester formation tended to decrease. On the other hand, the secondary alcohols such as 2-propanol, 2-butanol, 2-hexanol, and 2-octanol showed little ester conversion, suggesting that the steric hindrance strongly affected the transesterification of triolein.     

Sensor-less maximum power point tracking control for wind generation system with squirrel cage induction generator

This paper proposes a technique that determines the optimal windmill operation speed and the optimal rotor flux. Moreover, the position and speed sensor-less wind generation system using the electromotive voltage observer to estimate rotor position and full-order observer to estimate rotor speed and the windmill output torque are proposed. The position and speed sensor-less maximum power point of wind power generation system is controlled by using the above estimated values, optimized windmill operation speed for maximum output power and optimized rotor flux for minimum generator losses. The effectiveness of the position and speed sensor-less maximum power point tracking control for wind power generation system with squirrel cage induction generator is verified by simulations. The simulation results confirm that the proposed method can estimate the operation speed efficiently.     

A Realization of a Low-Voltage Differential-Output OTA Using a Simple CM Amplifier

A technique for realization of low-voltage OTAs is presented in this letter. A very low-voltage differential-output OTA is realized by employing a new common-mode amplifier in the common-mode feedback circuit. The results of PSpice simulations are shown. The proposed OTA can operate at a 0.9 V supply voltage.     

Study on decomposition gas for diagnostics of gas‐insulated transformers

Concentrations of population and business activities result in high energy demand in urban areas. This requires the construction of underground substations. Oil‐free, nonflammable, nonexplosive equipment is recommended for underground substations. For this reason, gas‐insulated transformers have been developed. A diagnostic method for gas‐insulated transformers is thus required. This paper provides an experimental survey of the main components of decomposition gas generated by various faults in gas‐insulated transformers carried out through simplified model tests. The phenomena of overheating and partial discharges are modeled, taking the actual materials related to each fault into account. For example, CO, CO₂, and aldehydes are produced by overheating of pressboards and PET films. The amount of gas produced increases with rising temperature. While various gases are produced from a partial discharge, the principal components are SO₂ and SOF₂. These results will be used to develop a diagnostic method for gas‐insulated transformers. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 48–58, 2000     

Carbon footprint assessment for the waste management sector: A comparative analysis of China and Japan

Waste management is becoming a crucial issue in modern society owing to rapid urbanization and the increasing generation of municipal solid waste (MSW). This paper evaluates the carbon footprint of the waste management sector to identify direct and indirect carbon emissions, waste recycling carbon emission using a hybrid life cycle assessment and input-output analysis. China and Japan was selected as case study areas to highlight the effects of different industries on waste management. The results show that the life cycle carbon footprints for waste treatment are 59.01 million tons in China and 7.01 million tons in Japan. The gap between these footprints is caused by the different waste management systems and treatment processes used in the two countries. For indirect carbon footprints, China’s material carbon footprint and depreciation carbon footprint are much higher than those of Japan, whereas the purchased electricity and heat carbon footprint in China is half that of Japan. China and Japan have similar direct energy consumption carbon footprints. However, CO₂ emissions from MSW treatment processes in China (46.46 million tons) is significantly higher than that in Japan (2.72 million tons). The corresponding effects of waste recycling on CO₂ emission reductions are considerable, up to 181.37 million tons for China and 96.76 million tons for Japan. Besides, measures were further proposed for optimizing waste management systems in the two countries. In addition, it is argued that the advanced experience that developed countries have in waste management issues can provide scientific support for waste treatment in developing countries such as China.