In ferrous metal smelting operations, each element is refined from very complex compound material in which the major elements are Cu , Zn and Pb. Especially in smelting Cu, it is very important to understand the complex morphology of the various compounds in the raw material because of its very diversity. This detailed understanding of the complex morphology is necessary for the high purification process of each element and to improve the refining efficiency. Currently, ICP, XRD and EPMA are used for the evaluation of the raw materials. However, ICP and XRD can provide information only about average composition and EPMA requires highly experienced analysts to operate the instrument and evaluate a mixed compound material. In this study we analyzed Cu-compound raw material by the auto phase analysis method using the multivariate statistical analysis of EDX spectral imaging data (Thermo Scientific COMPASS). We analyzed the phases which were extracted objectively by present method mentioned above. As the results of the analysis of the EDX spectral imaging data acquired for 30 minutes, we could confirm the 15 phases including Cu-Sn alloy (as the major component), Cu sulfide and compounds with rare elements such as Sb and As, and we recognized that those phases are mixed with the typical distribution.
A novel chemo-mechanical pressure control system for pumping applications was constructed and tested. The pressure control system utilizes direct conversion of chemical energy to mechanical energy by enzymatic reactions. In order to construct the system, glucose oxidase (GOD) and catalase (CAT) were immobilized onto a dialysis membrane with photosensitive resin. The enzyme immobilized membrane was functioned as a diaphragm of a reaction unit. Therefor, the reaction unit was divided into a top cell (gas phase) and a bottom cell (liquid phase). Characterization of the pressure control system was carried out by supplying hydrogen peroxide and glucose solution into the liquid cell, respectively. As a result, active pressure iincrease in the top cell induced by oxygen production due to decomposition of hydrogen peroxide and pressure decrease induced by oxygen consumption of GOD reaction. Thus, the pressure in the cell was successfully controlled by chemical energy. The possible application of the pressure controle system is a diaphragm pump which is driven with active pressure change.
In this study, a flexible glucose sensor with biocompatible polymer substrate for biomedical measurement was constructed and tested. The sensor was constructed by immobilizing an enzyme to biocompatible polymer substrate with electrodes. In the fabrication of the sensor, Pt-working and Ag/AgCl-counter/reference electrodes were formed onto a flexible polymer substrate by MEMS technique. In the immobilization process of an enzyme, a mixture solution of glucose oxidase (GOD) and PMEH as a biocompatible polymer was spread onto the sensing region of the electrodes, thus obtaining the flexible glucose biosensor with biocompatibility. In the evaluation of the sensor characteristics, the sensor was dipped into a measurement cell filled phosphate buffer, and then a +400mV potential was applied to Pt-working electrode vs. Ag/AgCl-counter/reference electrode by potentiostat controlled by PC. Various concentrations of glucose solution were dropped into the beaker and the output current of the sensor was measured by PC via A/D converter. As a result of characteristics evaluation, the output current rapidly increased immediately after the drop of glucose solution and linearly corresponded to glucose concentration over a range of 0.05-4.0mmol/l, with a correlation coefficient of 0.999. The result suggests that GOD was successfully immobilized onto the substrate. This sensor would be applied to detecting tear glucose of rabbit for continuous evaluation of blood sugar level in the near future.
A chemical motor was constructed by a catalase immobilized tube-pump and a micro turbine system was developed and demonstrated. The catalase tube-pump produced an active pressure of oxygen vapor at the tube-inside by applying hydrogen peroxide to the tube-outside as chemical energy, resulting in the oxygen gas flux. The micro bladed wheel of the artificial turbine was revolved by the oxygen flux from the tube-pump, thus the rotational velocity was correlated with the H2O2 concentration. The potential applications of the chemical motor will allow to develop some intelligent biomimetic machines.
The rat is one of the most popular experimental animals in medical fields. However, the rat is not so often used in complicated neurological studies because of its size of the brain. To investigate the localization of waveform of auditory brainstem responses (ABRs), two rats were examined. Twelve or 13 platinum-rhodium coated electrodes were implanted on the dura mater through the cranial bone. The waveform of ABRs with 6 peaks was clearly recorded. These peaks were comparable with those of the human. However, the latency of these peaks was slightly shorter compared with that of the human. These 6 peaks were clearly identified in the waveform measured on the occipital area. On the other hand, these peaks recorded in frontal region were fused together. From these results, electrodes should be placed on the occipital area of the cranial bone to identify these peaks originated from brainstem by the auditory stimulation. Therefore, it is expected that latency changes can be evaluated clearly. This measurement system has a new possibility to analyze the details of various kinds of evoked potentials waveforms.