Influence of holes on neutral trap generation

Using a newly proposed method for estimating the neutral trap density, generation characteristics of the neutral trap during various stress types have been investigated. From the analysis of the trap-generation kinetics, two types of trap generation closely related to holes have been identified. At the first stage of stress application, holes interact with the pre-existing structural origins of the neutral traps, then the neutral traps are generated. Influence of hole energy on this type of trap generation is also identified. After that, as holes pass, they also create the structural origins of the traps. The holes interact with these structural origins and the neutral traps are generated as a secondary effect. Thus, the increase in the neutral trap density shows up clearly with increase in the hole fluence. The stress-strength dependence of the increase in the neutral trap density can also be interpreted in terms of the influence of hole energy on the trap generation     

Screening of long-wavelength laser at high temperature and high current levels

It is found that electroluminescent mode aging at high-temperature and high-current levels is useful for selecting long-lived InGaAsP 1.3 ?m lasers. Lasers selected by this screening have little change in threshold current or forward voltage through the aging test at an elevated temperature with constant light-output power.     

A study of the buying price of photovoltaic electricity under a carbon tax regime

Assuming that photovoltaic (PV) systems are adopted in residential houses under a carbon tax regime, the economic performance of PV systems is investigated from the standpoint of an electric utility. The economic performance is estimated by using the buying price of PV electricity and the PV economic index, which is defined as the ratio of the buying price to the generation cost of the electric utility. Because these values depend on electric power development and operation, the best mix and the operation of power plants are obtained by linear programming subject to restrictions on power generation. Then, the buying price of PV electricity is calculated from the total cost of the electric utility. The buying price means the upper limit at which the electric utility never suffers a loss. The buying price is also compared with the power generation cost. The parameters are the prevalence attainment ratio of PV systems (0 to 100%), the upper limit of newly developed nuclear power plants (0 to 4 GW/10 y), and the generated energy ratio of coal‐fired thermal plants (0 to 15%). Chubu Electric Power Company, Inc. is used as the electric utility. The calculation results show that the buying price of PV electricity increases linearly with increasing carbon tax rate, and its values are 9 and 11.5 yen/kWh when the carbon tax rate is 0 and 25 thousand yen/t‐C, respectively, which does not depend on the prevalence attainment ratio of PV systems and the upper limit of newly developed nuclear power plants. It is not the carbon tax rate but the newly developed nuclear power plant that influences the PV economic index. The values of the PV economic index are 1.35 to 1.45 and 1.50 to 1.60 when the newly developed nuclear power plant capacity is 0 and 4 GW/10 y, respectively. These results show that the economic performance of PV systems is increased by developing nuclear power plants at a certain rate and introducing a carbon tax. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(2): 38–49, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10067     

Single-mode oscillation under high-speed direct modulation in GaInAsP/InP integrated twin-guide lasers with distributed Bragg reflectors

Spectral behaviour of 1.3 ?m GaInAsP/InP integrated twin-guide lasers with first-order distributed Bragg reflectors under high-speed direct modulation was measured. It was confirmed that stable single-longitudinal-mode operation is maintained for applied modulating current pulse width of only 1 ns. The rise time and width of the light output pulse were less than 0.3 and 3 ns, respectively.     

Laying season and egg shell cracks on the growth of Salmonella enteritidis in the egg albumen during storage

We studied the effects of laying seasons and egg shell cracks on the ability of egg albumen to support the growth of Salmonella Enteritidis (SE) in eggs. Hens eggs used were those laid in February, June, and October in a farm in Japan and stored at 10, 20, and 30 degrees C, and at 30 degrees C after storage at 10 degrees C, immediately after receipt or after cracking the shell. At several-day intervals during storage, the egg contents were poured into a dish, SE was inoculated into albumen, and then the growth of SE during 3 days incubation at 18 degrees C was measured. The results demonstrated that storage temperature and laying season affected the growth of SE in the egg albumen. The proportion of eggs upon which albumen allowed the growth of SE was higher in the eggs stored at 30 degrees C than those stored at 10 degrees C. The growth of SE in eggs was lowest in the following order of laying: February, October, and June. SE grew preferably in albumen of cracked eggs than intact eggs.     

Anisotropic carbon nanotube papers fabricated from multiwalled carbon nanotube webs

We fabricated large-scale anisotropic carbon nanotube (CNT) paper sheets by stacking long-lasting multiwalled CNT (MWCNT) webs without using binder materials. The MWCNTs are highly aligned in the webs and they retain their alignment in the fabricated paper. Although MWCNTs are just connected by van der Waals force, tensile strength is as strong as 75.6 MPa. In addition, resistivity and thermal conductivity is as good as 2.5 × 10⁻³ Ω cm and 70 W/m K, respectively. The present high anisotropy ratios of 7.3 in resistivity and of 8.1 in thermal conductivity are due to the high alignment of the ultra-long MWCNTs which have lengths of millimeters. High-speed web drawing with a draw speed of over 10 m/s enables very rapid fabrication. The material properties of CNT structures can be measured by conventional methods for macroscopic samples rather than methods designed for nanomaterials. CNT web technology will enable CNTs to be used in new applications.     

Peptidoleukotriene receptor antagonists in asthma therapy]

Peptidoleukotrienes reproduce some of the functional and histological features of clinical asthma, such as potent bronchoconstriction, airway microvascular leakage, mucus hypersecretion, eosinophilic airway infiltration, in addition to inducing bronchial hypersensitivity. An important role for peptidoleukotrienes has been demonstrated in experimental challenge studies in asthmatic patients and in acute asthma attacks. Antagonists of peptidoleukotrienes can inhibit bronchoconstriction in response to inhaled allergen, exercise or inhaled cold air, and oral or inhaled aspirin. These compounds demonstrate beneficial effects in clinical studies with improvement in symptoms and lung function. Peptidoleukotriene antagonists may provide a new therapeutic approach for the treatment of asthma.