Technique of Controlling Dust Generation during Oxygen Top Blowing in BOF

Dust generation behavior during BOF operation with minimal slag was investigated by measuring the dust concentration of the dust collecting water, and a dust generation model was proposed. In this model, the dust generation rate was expressed as a function of the carbon content in metal and the dynamic pressure at a metal surface of the oxygen top blown jet. As a result of controlling the dynamic pressure with the model, the dust generation rate during BOF operation was restrained and the oxygen blowing rate was increased by 10% to raise the productivity while maintaining the same rate of dust generation. To obtain data on the dust generation rate and clarify the behavior of the top blown jet, a new online system for measuring the dust generation rate for BOF was developed. The system enabled online continuous measurement of the dust generation rate by diluting the dust collecting water and using a colorimetric method to measure the dust concentration of the diluted dust collecting water. Application of the numerical simulation method to supersonic jets was considered and the behavior of the top blown jet was grasped in order to control the dynamic pressure. These tools were used to optimize the operating conditions and quickly evaluate the top blowing lance design under the Zero‐Slag‐Process.     

Changes of infrared absorption by light soaking and thermal quenching in a-Si : H

The light- and thermal-induced changes of Si---H bonds in undoped a-Si : H have been studied on the infrared absorption of Si---H stretching mode, using the infrared photothermal deflection spectroscopy and the photothermal bending spectroscopy. The results show that the IR absorption of Si---H bonds increases by light soaking of the high power 500 mW/cm². The change of IR absorption of Si---H bonds reoccurs by thermal annealing at 200°C. This change is related to the increase of the dangling bonds under light soaking. Furthermore, we observe the change of the elasticity modulus by light soaking, using the photothermal bending spectroscopy. The structural change in a-Si : H is discussed based on these results.     

日本水权体制中的水资源配置及管理

在日本,用水单位可自由使用取水设施,干旱季节水资源的合理配置就成为一个突出的问题.目前,日本的干旱季节会有多种用水分配分式.对于KOKAI河流域的水资源分配,水的配给制度沿用了传统的方式,即地形条件占有决定性的地位,没有特殊的手段去控制水资源的公平配置.而对于YAHAGI河流域的水资源分配,各用水单位建立了一个非政府的水资源配置委员会.尽管灌溉部门掌握用水优先权,但是在严重干旱期农民会将水资源转让给供水部门.     

Age at onset and language disturbances in Alzheimer's disease

This study examined the effect of age at symptom onset of Alzheimer's disease (AD) on the pattern of language disturbance. We assessed 150 consecutive patients with a clinical diagnosis of mild-to-moderate AD using the Western Aphasia Battery and a 100-item picture-naming test. A multivariate linear regression analysis examined the effect of age at onset after controlling for gender, education, severity of dementia and duration of the disease. Patients with early onset performed significantly worse than did patients with late onset on the word comprehension and sequential commands subtests. On the other hand, late-onset patients performed more poorly than early-onset patients on the picture-naming test in a subgroup with mild language deficits. However, the trend disappeared in other subgroups with more degraded language function. We consider that the concomitant effects of normal aging worsened the picture-naming deficits in the late-onset patients, and the rapid decline of naming ability in the early-onset patients masked the aging effect with the progression of language deficits. The deterioration of word comprehension and the rapid decline of naming ability are the characteristics of early-onset patients. The different patterns of language deficits between early- and late-onset patients may correspond to the genetic heterogeneity of AD.     

Ossification of posterior longitudinal ligaments: evaluation with MRI

Ossification of the posterior longitudinal ligament is a special subcategory of degenerative disease responsible for compression of the spinal cord. On MR images, T2-weighted sequences are the most effective to evaluate both spinal cord compression due to the ossification and abnormal signal intensity of the cord. Although ossification of the ligaments is well demonstrated on CT and plain radiographs, MRI noninvasively provides useful information about the degree and extent of spinal cord compression, as well as the character of the ossification.     

A damping of rotor natural vibration in three‐phase hybrid stepping motors

This paper proposes a damping method of rotor natural vibration in three‐phase hybrid stepping motors, in which optimal commutation signals are calculated from the period of the natural vibration measured by detecting the motor voltages. Moreover, an acceleration and deceleration pattern is derived from a simple model of the rotor vibration, to suppress undesirable transient oscillation in acceleration, deceleration, and positioning operations. An experimental drive system has been implemented and tested to confirm the effectiveness and versatility of the proposed method. Some experimental results show that the experimental system can damp the rotor natural vibration even if the rotor inertia varies. Compared with the conventional pattern, it is confirmed that the proposed pattern makes a great contribution to damping the undesirable transient oscillations. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(3): 69–77, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10153     

Measurements of 220 GHz atmospheric opacity on Mt. Fuji with a radiometer/radome system

We measured atmospheric opacity at 220 GHz at the summit of Mt. Fuji (alt. 3776 m) about one year in order to explore a feasibility of submillimeter-wave astronomical observations. For this purpose, a 220 GHz radiometer system enclosed in a radome (51×51×62 cm³) has been developed. The 220 GHz opacity was lower than 0.06 for a significant fraction (～ 45 %) of time from November 1994 to March 1995. Diurnal variation of the opacity at the summit of Mt. Fuji is so small that continuous observation at submillimeter-wave is possible through day and night. Yearly variation of the opacity is studied from water vapor pressure data measured at the weather station for the past 3 years. To prevent accumulation of ice and snow on the Gore-Tex membrane in the radome, the outer membrane was supplied with a thermal flux of 0.63 kW m^?2 and the adjacent metal radome surfaces were supplied with a flux of ～0.9 kW m^?2. We evaluate from the 220 GHz transmission data that this heat flux is sufficient to keep the membrane on the radome free of ice and snow during 83 % of the time in 5 winter months. The summit of Mt. Fuji appears to be a promising site for submillimeter-wave observations.     

Patterning of CVD diamond films by seeding and their field emission properties

Selective seeding for growing diamond on Si substrates was performed by conventional lithography using photoresist mixed with fine diamond particles. The selectivity was improved by filtering the diamond powder-photoresist mixture and carrying out reactive ion etching of patterned substrates. As a result, a selectivity up to 2.0 × 10² or higher was achieved. The resolution was of the order of 1 μm. Field emission from diamonds prepared using this selective growth method was observed without any postgrowth treatment. The measured current vs. voltage plot of a diode showed a rectifying characteristic. Under a forward bias, a current of about 15 μA was obtained at about 570 V, with a turn-on voltage of about 480 V. The emission current was comparable with that which had been observed for Si field emitter tips.     

The antigen-bearing eye and the spleen are indispensable in maintaining anterior chamber-associated immune deviation

PURPOSE: To investigate the role of the eye and the spleen in maintaining suppression of delayed-type hypersensitivity (DTH) after anterior chamber (AC) inoculation of allogeneic splenocytes. METHODS: Suppression of DTH response was tested in BALB/c mice after AC inoculation of allogeneic B10.D2 splenocytes. Seven days after AC injection, the antigen-inoculated eyes were enucleated or the spleens were removed. After enculeation or splenectomy at different time intervals, DTH responses in groups of the BALB/c mice were examined. Spleen components obtained from BALB/c mice that had been primed by B10.D2 splenocytes in the AC 7 days earlier were transferred intravenously to groups of naive syngeneic acceptors. At various intervals after adoptive transfer, variations of DTH responses were tested. RESULTS: Inoculation of B10.D2 splenocytes to the AC of BALB/c mice induced antigen-specific suppression of DTH. Either enucleation of the antigen-inoculated eyes or splenectomy weakened the DTH-suppressive effect within 5 weeks and abolished it within 9 weeks, whereas the mice retaining both antigen-inoculated eyes and spleens maintained longstanding DTH suppression. Adoptive transfer of spleen components to syngeneic acceptors demonstrated DTH suppression for only 3 weeks. CONCLUSIONS: The antigen-inoculated eye and spleen are required for long-standing suppression of DTH after AC inoculation of allogeneic splenocytes.     

The characterization of electrodeposited Zn-SiO2 composites before and after corrosion test

The microstructure of electrodeposited Zn-SiO₂ composites before and after corrosion tests has been studied by using scanning electron microscopy-energy dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. As-deposited Zn-SiO₂ composites are composed of SiO₂-rich and SiO₂-poor phases. After a wet and dry cyclic corrosion test, including NaCl solution spray, zinc hydroxychloride is formed on the SiO₂-rich phase which surrounds the uncorroded SiO₂-poor phase. Zinc hydroxide, zinc oxide and zinc hydroxychloride are also formed on the surface of the Zn-SiO₂ composites. The high corrosion resistance of the composites is attributed to the formation of protective corrosion products in the composite layer supported by SiO₂.