Influence of substrate bias voltage on properties of Pt thin films deposited by non-mass separated ion beam deposition method

Pt thin films were deposited on Si substrates by applying a negative substrate bias voltage using a non-mass separated ion beam deposition method. The effect of the substrate bias voltage on the properties of the deposited films was investigated. In the case of Pt thin films deposited without the substrate bias voltage, a columnar structure and small grains were observed. The electrical resistivity of the deposited Pt films was very high (49.3 ± 0.65 µΩ cm). By increasing the substrate bias voltage, no clear columnar structure was observed. At the substrate bias voltage of − 75 V, the resistivity of the Pt film showed a minimum value of 16.9 ± 0.2 µΩ cm closed to the value of bulk (10.6 µΩ cm).     

Effect of substrate bias voltage on the texture and microstructure of Cu thin films deposited by ion beam deposition

Cu thin films deposited by non-mass separated ion beam deposition under various substrate bias voltages were investigated. The film textures and microstructure were analyzed by X-ray diffraction and field emission scanning electron microscopy, and the resistivity of the film was measured with the Van der Pauw method. It was found that the optimum negative substrate bias voltage for Cu films was −50 V. The Cu films deposited without substrate bias voltage showed a columnar grain structure with small grains and random orientation. However, when a substrate bias voltage of −50 V was applied, the Cu films had a non-columnar structure with a strong (111) texture and large grains. The electrical resistivity of the Cu films decreased remarkably with increasing negative substrate bias voltage, and reaching a minimum value of 1.8±0.13 μΩ cm at the substrate bias voltage of −50V.     

Purity evaluation of Ta metal refined by Ar/Ar−H<Subscript>2</Subscript> plasma Arc melting

The refining effect of Ar/Ar-H₂ plasma arc melting (PAM) was investigated and the purity of Ta metals was evaluated by glow discharge mass spectrometry (GDMS). Most impurities in the Ta metals were removed by Ar/Ar-H₂ PAM, down to a few mass ppm levels, and the purities of respective Ta metals refined by Ar/Ar-20% PAM were improved up to 5N5 (99.9995 %) and 5N7 (99.99972 %). It was also found that the deoxidation reaction under hydrogen plasma condition is enhanced by a remarkable decrease in the oxygen concentration of the Ta metal refined by Ar-H₂ PAM.     

Removal of boron from coal fly ash by washing with HCl solution

Boron as an environmentally regulated substance is well known to condense in the coal fly ash generated from coal combustion plants. Since boron in the coal fly ash tends to elute into the soil easily, a technology for its stabilization or removal from fly ash is required. An acid washing process is proposed and studied as one of the candidate technologies for the removal of boron from coal fly ash. A laboratory-scale investigation is conducted on the dissolution behavior of boron in the coal fly ash in a diluted HCl solution. The dissolution of boron and alkaline species is considerably fast and exhibits a behavior different from that of aluminum and silicon, which are major components of the ash. From the kinetic model, it is expected that boron in the ash may mainly be in the form of alkaline or alkaline earth borates that are deposited on the surface of relatively large ash particles of alumino-silicate or may be precipitated as fine particles during coal combustion. This acid washing process is extended to a bench-scale plant and boron is successfully removed from the coal fly ash until its content is less than the regulation limit.     

A node configuration algorithm with bandwidth bottleneck resolution for WDM ring networks

The wavelength-division multiplexing (WDM) technology has been extensively studied and actually deployed as a key technology to solve global information explosions by multiplexing plural signal paths using different wavelengths into one optical fiber. Among WDM-based network architectures, this article focuses on a double-ring one for a next-generation metropolitan area network (MAN), where each node is normally equipped with two pairs of fast-tunable transmitters and wavelength-fixed receivers (TT-FR) as interface to two fibers. To enhance the network performance, additional transmitters/receivers at nodes and receiver wavelengths should be assigned optimally, so that the bandwidth bottleneck can be resolved both on nodes and fiber links. This article formulates this node configuration problem with bandwidth bottleneck resolution as a combinatorial optimization problem, and proves the NP-completeness of its decision version. Then, it presents the two-phase heuristic algorithm composed of a greedy method and a variable depth search (VDS) method. Our algorithm is evaluated through extensive network simulations, where the results support the effectiveness of this joint assignment approach.

Inhibitory effect of essential oils, food additives, peracetic acid and detergents on bacterial histidine decarboxylase

The aim of this study is to examine whether various essential oils, food additives, peracetic acid and detergents inhibit bacterial histidine decarboxylase. Crude extract of Morganella morganii NBRC3848 was prepared and incubated with various agents. Histidine decarboxylase activity was significantly inhibited (p<0.05) by 26 of 45 compounds tested. Among the 26 agents, sodium hypochlorite completely decomposed both histidine and histamine, while peracetic acid caused slight decomposition. Histidine and histamine were stable in the presence of the other 24 agents. These results indicated that 25 of the agents examined were inhibitors of histidine decarboxylase.     

Food protective property of new liquid food container PID (Pouch in Dispenser) for microbes

We examined the content protection characteristics of the PID (Pouch in Dispenser) when it was used in the usual manner and when it was polluted artificially. When the PID was used in the usual manner, the nozzle was opened, and experiments were carried out with and without air-blowing. The invasion of bacteria into the PID was not detected. Also, no bacteria were detected in the material poured from the nozzle of the PID. When 3 strains of bacteria suspensions were intentionally smeared on the nozzle of the PID, invasion of bacteria was observed. When the PID was wiped with a dirty cloth, no invasion of bacteria into the PID was detected. It may be necessary to label the PID with the instruction that the nozzle should not be touched. The effected of changes in the water activity and pH, and the preservatives used, may also need to be considered, depending on the contents in the PID.     

1.3-μm Pr-doped In-Ga-based fluoride fiber amplifiers pumped bygrating-fiber-pigtailed 0.98-μm-band laser diodes with a detunedwavelength of 1 μm

At most efficient pump wavelength, a praseodymium-doped In-Ga-based fluoride fiber is directly pumped by four 0.98-μm-band laser diodes. These lasing wavelengths are detuned from 0.98 to 1 μm by external selective optical feedback from fiber grating reflectors. Maximum signal output power of +13.5 dBm is obtained at 1.296 μm. Four-wavelength multiplexed signals at 1.296-1.311 μm are amplified with a deviation of gain less than 1.9 dB. By using the amplifier as a power booster, data of 2.5 Gb/s is successfully transmitted more than 100 km     

Platelet aggregation in acute coronary syndromes: use of a new aggregometer with laser light scattering to assess platelet aggregability

PURPOSE: To describe the computed tomographic (CT) appearance of hepatic infarcts resulting from arterial insufficiency in native livers. MATERIALS AND METHODS: The authors retrospectively reviewed the clinical and imaging findings in 10 patients (five men, five women; age range, 28-70 years) with 14 hepatic infarcts seen over 3 years. CT scans were analyzed for infarct appearance, vessel patency, and evolution of infarct pattern over time. RESULTS: Hepatic infarction resulted from hepatobiliary surgery (n = 6), radiologic intervention (n = 3), and celiac occlusion secondary to antiphospholipid syndrome (n = 1). All 14 infarcts were of low attenuation, peripheral, and wedge-shaped. Occluded arterial vessels were identified in eight patients. Follow-up CT revealed infarct diminution with parenchymal atrophy and scarring (n = 5), progressive liquefaction (n = 2), or both parenchymal atrophy and progressive liquefaction (n = 1). CONCLUSION: Sudden interruption of hepatic arterial flow may cause acute native liver infarction. Patients at risk include those with underlying vascular disease who undergo complicated surgical procedures and those undergoing peripheral arterial embolization.