Reduction of depth variation in an Si etching process by applying an optimized run-to-run control system

A reduction of depth variation in a shallow trench isolation process is desired for obtaining more stable electrical performances of silicon devices. By applying an optimized run-to-run control system to a silicon trench etching process, trench depth variation of the process was reduced. Cp/Cpk of the trench depth of product wafers were improved from 1.10/0.83 to 1.39/1.34 by the control.     

Rapid Reconstitution of Biosynthetic Machinery for Fungal Metabolites in Aspergillus oryzae: Total Biosynthesis of Aflatrem

Reconstitution of the biosynthetic machinery for fungal secondary metabolites in Aspergillus oryzae provides an opportunity both for stepwise determination of the biosynthetic pathways and the total biosynthesis of fungal natural products. However, to maximize the utility of the reconstitution system, a simple and rapid strategy for the introduction of heterologous genes into A. oryzae is required. In this study, we demonstrated an effective method for introducing multiple genes involved in the biosynthesis of fungal metabolites by using the expression vectors pUARA2 and pUSA2, each of which contains two cloning sites. The successful introduction of all the aflatrem biosynthetic genes (seven genes in total) after two rounds of transformation enabled the total biosynthesis of aflatrem. This rapid reconstitution strategy will facilitate the functional analysis of the biosynthetic machinery of fungal metabolites.     

Molecular-dynamic simulations of martensitic transformation of cobalt

With a potential-energy function of Co described by the embedded-atom method (EAM), molecular-dynamics (MD) simulations were performed for a series of initial fcc configurations with different types of dislocations or preset hcp embryos. The gliding process of a Shockley dislocation on a closepacked plane has been observed, which starts from the origin of the dislocation and proceeds at a high speed of 280 m/s toward a certain direction. An atom which has been swept by the dislocation line was detected to contribute a displacement close to the Burgers vector of a Shockley dislocation. It is in this way that a new stacking sequence is produced and an hcp lamella grows in the fcc structure. A similar gliding process has been observed in the case where an intrinsic stacking fault is preexisting in the fcc structure. The transformation is, again, toward forming a local hcp region. These results prove that a special dislocation in the fcc structure can act as an embryo of the hcp, as described in many dislocation mechanisms of the martensitic transformation. The fcc → hcp phase-tranformation process of Co has been further reproduced by a simulation initiated from an fcc/hcp two-phase configuration. It yields a single hcp crystal as the final transformed product.     

Studies of the network structure of rubber vulcanizates by cryoscopic methods: 2

The freezing point depression, ΔT, of swollen DCP-, TT- and sulphur-cured natural rubber in benzene was observed. The dependence of the parameter, a_H, introduced by Kuhn, was not affected by the type of structure of crosslink sites. It was found from the comparison of the experimental results and scaling law that a_H can reflect not only the difference in three-dimensional structure of network between a degraded and an undegraded rubber vulcanizates but also the difference in degraded network structures between rubber samples with various conditions of degradation.     

Novel mode scrambler for reducing mode dependence in multimode optical waveguides

A novel mode scrambler for multimode optical waveguides is proposed to stabilise branching characteristics against the mode excitation conditio. A 2 × 2 optical star coupler is fabricated using this mode scrambler, and a stable branching ratio is realised with an excess insertion loss of 2.7 dB.     

Theoretical considerations on the sensitivities of electron beam resists

A theoretical study has been carried out in order to explain the sensitivities of electron beam and X-ray resists. A preliminary investigation reveals that the behavior of these resists, on irradiation by high energy radiation, may be considered to be the electronically-excited species in the polymer. To elucidate the chemical reactions in the excited states the adiabatic potential curves are calculated by the INDO/S procedure, which considers all the valence electrons and all the singly excited electronic configurations. Polyethylene and polyisobutylene were chosen as representative of crosslinkable and degradable polymers, respectively, since there is a parallelism between the beam sensitivity of resists and the effects of high energy radiation on polymers. Polyisobutylene has many antibonding curves favorable for the main chain scission in the excited states and polyethylene does not except for one improbable state. It was concluded that degradability is explainable by the ease of bond fission in the excited states; the crosslinkability is considered to be nondegradable property.     

Nonreentrant supraventricular tachycardia due to double ventricular response via dual atrioventricular nodal pathways

In twenty eight patients with iron deficiency the efficacy of iron-acetil-transferrin treatment (2-3 mg/kg/die) has been evaluated from the changes of the following variables: RBC and reticulocyte count, Hb concentration, MCV, MCH, serum ferritin, serum iron, TIBC, and ZnPP. These variables were assessed before and after three months of treatment in all patients, and after three months from the end of the treatment in thirteen patients. At the end of the treatment there was a significant increase of RBC count, Hb concentration, MCV, MCH, serum ferritin, serum iron, and TIBC, a significant decrease of ZnPP, while reticulocyte count remained essentially unchanged. After three months from the end of the treatment only serum ferritin and ZnPP underwent an additional significant increase and decrease, respectively. In twenty-six patients serum ferritin values returned to normal. The changes of RBC and reticulocyte count, Hb concentration, MCV, serum iron, and TIBC were larger the lower the initial values, suggesting that the efficacy of the treatment is greater the more serious the iron deficiency.     

Schiff's bases of polyallylamine

Summary Schiffs bases of polyallylamine were synthesized by the reaction with four aldehydes. Salicylaldehyde (S)- and 2-pyridinecarboxaldehyde (P)-Schiff's base could be used as reverse osmosis membranes when crosslinked with divinyl sulfone, diacetyl or ethylene glycol diglycidyl ether. S-base membrane had a high mechanical strength but poor water permeability (K₁), while P-base membrane showed a high rejection, particularly against CoCl₂, and a high K₁ because of chlate formation, but poor strength. The membranes of P-base and a hybrid PS-base exhibited a possibility of separating alkali metal salts and transition metal salts from each other.     

Studies of the network structure of rubber vulcanizates by a cryoscopic method: 1

The freezing-point depression, ΔT, of swollen dicumene peroxide cured natural rubber in benzene has been measured. The parameter a_H, introduced by Kuhn, which varies inversely as ΔT, should be regarded as an indication of the depression. The anomalous depression is considered to occur due to a non-frozen benzene area formed on the surrounding network chains. From comparison of the scaling law and the experimental results, it was clear that a_H can reflect not only the quantity corresponding to network chain density determined by conventional methods but also the difference in three-dimensional network structure between degraded and undegraded rubber vulcanizates.