• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.11 no.2
• /
• pp.172-177
• /
• 2000

Background and Objectives : Until now, various attempts have been made fir reinnervating paralyzed vocal cord. Nevertheless, the most cases did not produce satisfactory outcome due to occurrence of synkinesis of larynx secondary to misdirected axonal regeneration. Accordingly, the purpose of this investigation is to learn the effect of chronic electrical stimulation on regeneration of the recurrent laryngeal nerve. Material and Methods : Using 20 healthy male Sprague-Dawley rats(250-300g) with normal vocal functions, transections were made on their left recurrent laryngeal nerves and then primary anastomosis were performed under the operating microscope and they were divided into an experimental group and a control group each having 10 rats. After the procedure, for the experimental group, chronic electrical stimulation was carried out until vocal cord movement was functionally recovered. for the control group, only chronic electrical stimulation was not given. Result : In experimental group, the number of functionally recovered rats was two and in control group, that of functionally recovered rate was same. The reorganization of posterior cricoarytenoid muscle motoneuron in nucleus ambiguus appeared in the case of directed reinnervation of recurrent laryngeal nerve. Conclusion : The chronic electrical stimulation does not a direct beneficial effect on the early functional recovery in rats with injured recurrent laryngeal nerve.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.3
• /
• pp.315-322
• /
• 2007

The purpose of this study was to investigate the biodegradability and performance of organic removal and methane production rate when treating piggery wastewater using a granule of two-phase anaerobic process applied UASB. BMP test was conducted as simple means to monitor relative biodegradability of substrate and to determine methane production of an organic material. The two-phase anaerobic process is consisted of a continuous flow stirred-tank reactor (CFSTR) for the acidification phase and an Upflow Anaerobic Sludge Blanket reactor (UASB) for the methanogenesis. The acidogenic reactor played key roles in reducing the periodically applied shock-loading and in the acidification of the influent organics. A stable maximum biogas production rate was 400mL. The methane contents ranged from 73 to 80% during the experimental period. It is known that most of the removed organic matter was converted to methane gas, and the produced biogas might be high quality for its subsequent use.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.11
• /
• pp.1410-1417
• /
• 1999

A thorough understanding of the transient behavior during start-up is essential in the design and operation of the heat recovery steam generator(HRSG). During this period of time, material that is exposed to high temperature and experiences a large temperature variation is subject to high thermal stress. In this work, a transient formulation of the HRSG is constructed including the estimation of the thermal stress and fatigue of the drum wall. Start-up behavior of a single-pressure HRSG is analyzed and the effect of bypassing part of the gas turbine exhaust flow on the thermal stress evolution is examined. It is found that the modulation of the gas flow rate using a bypass damper is very useful in view of reducing the thermal stress of the drum and ensuring the fatigue lifetime.

• Electrical & Electronic Materials
• /
• v.10 no.3
• /
• pp.233-238
• /
• 1997

We have investigated gas-detection characteristics of CuTBP (Copper-tetra-tert-butylphthalocyanine) chemiresistor devices exposed to air/200ppm N $O_{2}$ gases. The CuTBP films were made by Langmuir-Blodgett (LB) techniques. Sensitivity, response time, recovery time, and reproducibility of the devices were measured by current voltage characteristics. Interdigital electrode was used to improve the sensitivity. It was observed that a conductance G increases monotonically as the number of interdigital electrode finger pairs increases. As the number of interdigital electrode finger pairs increases, the sensitivity S( $G_{gas}$/ $G_{air}$) increases more than 50 times and stable. But the response time was delayed. The average recovery time of the CuTBP chemiresistor devices turned out to be about 100 second. We have also investigated applicability of the CuTBP chemiresistor device for a gas sensor.sor.

• Journal of the Korean Wood Science and Technology
• /
• v.18 no.1
• /
• pp.15-23
• /
• 1990

Roughage feeds were produced from Hyun-aspen (Populus alba $\times$ P. glandulosa) by autohydrolysis. The objectives of this work were to find proper conditions for the treatment of Hyun-aspen by analyzing the compositional change and digestibility and to determine the content of sugar and phenol contained in liquor extracted by digestion. The results of this work were as follows: 1. The proper condition for autohydrolysis of Hyun-aspen chips were $160^{\circ}C$ and 30 minutes in an autoclave. The yield of potential feed from original material and digestibility were 91.3% and 38.9% respectively 2. According to cooking conditions the sugar concentration of extracted solution and the recovery rate of sugar were 0.1~2.5%, 0.3~14.6% respectively. The phenol concentration of extracted solution and the recovery rate of phenol were 0.1~0.3, 0.5~1.8% respectively.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• v.y2004m10
• /
• pp.21-26
• /
• 2004

This study deals with the Hydrated Ability of the Ready-Mixed Concrete's Sludge which is the recycling technology of that sludge. The experiment gathers sludge from Ready-mixed factory. shatters these into pieces in dry condition and understands the differences between current using Portland cement. And then. this examines the possibility of the recycle as a bonding agent through the Compressive Strength and considers the recovery of the hydration. This experiment concludes the same Chemical Composition with the normal Portland cement. while. under the appropriate procedure in hydration recovery. this sludge can be used as the bonding agent in cement. The chemical composition of solid Remicon sludge shows that it has 1.8 times $SiO_2$ than the normal Portland cement. meaning lots of aggregate in Remicon sludge. Also. the specific gravity of Remicon sluge increases with the rise of Baking Temperature and has no difference between 2.77 and 2.94. The mortar flow used for combining the baking material of Remicon sludge does was not changed and is the highest between $750^{\circ}C{\cdot}120min\;and\;800^{\circ}C{\cdot}180min$. Additionally. the Compressive Strength increases with the age, certifying the same Hydrated Ability like cement and the best condition for hydration is $750^{\circ}C{\cdot}120min.$

• Textile Coloration and Finishing
• /
• v.5 no.4
• /
• pp.79-91
• /
• 1993

The purpose of this study is to prepare the newer, more comfortable of urea-formaldehyde resin finished fabrics. The methods of this study are by making examinations and comparisons the relations between the thickness, fabrics counts, weight, moisture regain and crease recovery of cotton and viscose rayon fabrics caused by condition of urea-formaldehyde resin finishing and warm retaining ability and warm-cool sense. The analytic results of thermal character in state of fabrics material finished with urea-formaldehyde are as follows: 1. The warm retaining ability has no correlation with mixing ratio of resin but the increase of the warm retaining ability has correlation with the increase of concentration of urea-formaldehyde resin. 2. The result pf multiple regression analysis for effect of physical property according to the concentration of resin to the warm retaining ability revealed as below. As the weight, thickness and density increase and moisture regain decreases, the warm retaining ability increases. 3. The qmax value has no correlation with mixing ratio of resin but the increase of the qmax value has correlation with the increase of resin concentration. In the end, the effect of it promotes cool sense. 4. The result of multiple regression analysis for effect of physical property according to the concentration of resin to the qmax value revealed as below. As he weight and thickness increase, the qmax value decrease. But, as the density and crease recovery increase, the qmax value increase.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.17 no.9
• /
• pp.839-848
• /
• 2005

Plastic plate heat exchangers have many advantages over the conventional heat exchangers such as aluminum plate heat exchangers, rotary wheel heat exchangers and heat pipe heat exchangers which have been used for ventilation heat recovery in the air-conditioning systems. In the present study, pressure drop and heat transfer characteristics of plastic plate heat exchangers are investigated for various design parameters and operating conditions which affect the performance of the plastic plate heat exchangers. In flat plate type heat exchanger, material thickness and channel height of heat exchanger are considered, and corrugate size and heat transfer area are considered in case of corrugate type heat exchanger. Pressure drop and effectiveness of the corrugate type heat exchanger increase as the corrugate size decreases.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.5 no.4 s.19
• /
• pp.29-36
• /
• 2005

In this study, relations among unconfined compressive strength, strain at maximum strength and depth were compared with each other. Test specimen is marine clay originated from the place near Ga-duck island in Busan city. In addition, influence of impure material contained in specimen and that of total core recovery(TCR) on unconfined compressive strength and degree of disturbance were investigated. As a result of tests, unconfined compressive strength decreases as strain corresponding to maximum strength increases. Also, the deeper the sampling depth and the bigger the TCR, the unconfined compressive strength increases. Especially, as the TCR increases, the unconfined compressive strength Increases and quality of specimen is enhanced.

• Radioisotope journal
• /
• v.21 no.4
• /
• pp.38-45
• /
• 2006

A new herbal composition. HemoHIM, was developed using irradiated animal models and was successfully applied as an immune-improving agent. In a view that the protection and recovery of immune, hematopoietic and self-renewal tissues are essential for radioprotective agents, HemoHIM was developed based on a novel combination of three edible herbs (Angelica Radix, Cnidii Rhizoma. Paeonin Radix) that meet all those requirements. HemoHIM significantly protected the immune and hematopoietic system and enhanced their recovery in y-irradiated mice. For the application of HemoHIM as a health functional food and a supplementary agent for the cancer patients, the efficacy of HemoHIM to improve the immune functions was further evaluated in immune-depressed animals and humans. Animal studies demonstrated that HemoHIM significantly improved the immune functions in cyclophosphamide-treated mice, aged mice, and dexamethasone-treated mice. In human studies, HemoHIM enhanced the immune activity and cytokine secretion in sub-healthy volunteers, and alleviated the severe leukocyre depression in cancer patients during radiation and chemotherapy. Based on these results, HemoHIM was approved by Korea FDA as a material of health functional food for immune function improvement and will be commercially available soon. This case of HemoHIM research and development suggested that irradiated animals can be good models for biological degenerations such as immune depression, self-renewal tissue damage, and aging for the development of biological modulators.