• Resources Recycling
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• v.7 no.3
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• pp.11-16
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• 1998

Simulated waste liquid containing 50 ppm cobalt ion was t$\xi$sted by precipitate flotation using a sodium lauryl sulfate as a c collector. The effects of initial cobalt ion concentration, pH, surfactant concentration, flotation time, gas flow rate and foreign i ions on removal efficiency of cobalt ion were studied. Pretreatment of the waste liquid with 35% $H_2O_2$, prior to precipitate f flotation made shin of optimal flotation pH from the strong alkalinity to weak alkaline range and made a favorable flotation of c cobalt ion in wide range of pH. For the result of this experiment, 99.8% removal efficiency was obtained on the conditions of initial coball ion concentration 50 ppm, pH 9.5 gas flow rate 70 mllmin, flotation time 30 min. The simulate ion was fanned t to be the most harmful ion against removal of cobalt by precipitate flotation of the species which were tested The presence of 0.1 M of $SO_4^{2-}$ ion decreased remo,때 $\xi$폐iciency of cobalt to 90% while the cobalt were almost entirely removed in the a absence of sulfate ion.

• Resources Recycling
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• v.13 no.2
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• pp.39-46
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• 2004

The amount of electric furnace dust has been steadily increasing due to the increase of iron scraps which are usually recycled by electric furnace melting process. To date, this electric furnace dust has usually been treated by landfilling, however, because of shortage of landfill sites and heavy metal leaching more desirable treatment schemes are urgently needed. Among several possible schemes for the proper treatment of electric furnace dust, its recycling can be said to be most desirable. In present study, the triboelectrostatic separation of zinc and zinc-containing components from electric furnace dust was attempted based on its physicochemical properties such as particle shape, size distribution, and chemical assay. The dust was found to be mixed with spherical and non-spherical shaped particles and its major component materials were $ZnFe_2$$O_4$, ZnO, Fe, Zn, and FeO. The content of zinc-containing components in the entire dust was observed to be in the range of 15～30 wt%, which reasonably justified that zinc is recyclable. The triboelectrostatic characteristic of each component material was found to be different each other since their work functions were different, and based on this characteristic zinc and zinc-containing component could be flirty separated from the dust. After selecting a proper tribo-elec-trification material, the separation features of zinc and zinc-containing component were examined by taking the distance of electrodes, electric field strength, and scavenging as the experimental variables. The highest zinc-content obtained under the optimal separating condition was found to be up to 50wt%.

• Resources Recycling
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• v.19 no.6
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• pp.51-60
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• 2010

A study on the recovery of cobalt and lithium from Lithium Ion Battery(LIB) scraps has been carried out by a physical treatment - leaching - solvent extraction process. The cathode scraps of LIB in production were used as a material of this experiment. The best condition for recovering cobalt from the anode scraps was acquired in each process. The cathode scraps are dissolved in 2M sulfuric acid solution with hydrogen peroxide at $95^{\circ}C$, 700 rpm. The cobalt is concentrated from the leaching solution by means of a solvent extraction circuit with bis(2-ethylhexyl) phosphoric acid(D2EHPA) and PC88A in kerosene, and then cobalt and lithium are recovered as cobalt hydroxide and lithium carbonate by precipitation technology. The purity of cobalt oxide powder was over 99.98% and the average particle size after milling was about 10 lim. The over all recoveries are over 95% for cobalt and lithium. The pilot test of mechanical separation was carried out for the recovery of cobalt from the scraps. The $Co_3O_4$ powder was made by the heat treatment of $Co(OH)_2$ and the average particle size was about 10 ${\mu}m$ after grinding. The recovery was over 99% for cobalt and lithium each other and the purity of cobalt oxide was over 99.98%.

• Resources Recycling
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• v.22 no.3
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• pp.73-80
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• 2013

Metal prices are rapidly rising due to increasing demand of metals and limited available resources according to the industrial requirement. As a result, securing a stable supply of these metal resources has been recognized as a core element of national competitiveness and sustained economic growth. In the case of magnesium and its alloys which are entirely depending on import, low-grade magnesium scraps from end-of-life vehicles and 3C(Camera, Computer, Communication) parts and magnesium wastes such as sludge and dross generated during melting process are hardly recycled. Accordingly, the development and commercialization of recycling technology of low-grade magnesium scrap is desperately needed to improve efficiency of resource circulation and to establish the required proprietary of resource metal supply and demand. In this study, papers and patents on recycling technologies of waste magnesium were analyzed. The range of search was limited in the open patents of USA (US), European Union (EP), Japan (JP), Korea (KR) and SCI journals from 1974 to 2012. Patents and journals were collected using key-words searching and filtered by filtering criteria. The trends of the patents and journals was analyzed by the years, countries, companies, and technologies.

• Tunnel and Underground Space
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• v.26 no.6
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• pp.455-465
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• 2016

The collapse of underground mine development void for mineral resources can cause the subsidence of ground surface. In order to prevent the subsidence of ground, data such as maps or pictures of past mining site is important information for current mine reclamation works. In particular, mine subsidence management was based on mining maps and pictures. The process of the mining area surveys, safety evaluation, and ground reinforcement are normally possible with information such as maps and pictures in past mining. During the Japanese colonial period and 1960's, a lot of mines were developed in Korea indiscriminately. However, mining information at that time is limited to use. In the future, mining information will become even more rare. MIRECO intends to establish a realistic alternative solution. In this study, the basic numerical information of developed mine tunnels in Korea is statistically reviewed, and advanced underground cavity measuring technology was studied. 4,473 mine tunnel opening data of 1,784 abandoned mines in korea were collected and sorted. As a result of the analysis, the average value of small mine tunnel openings in Korea was 1.982 m in height and 1.959 m in width. The mean value of shape factor was analyzed as 0.485. The summary of these numerical mine data will be helpful for understanding and researching Korean abandoned mines. Therefore, the development of measurement technology for abandoned mine cavities and tunnels is expected to facilitate more effective mine subsidence management works in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.323-335
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• 2015

Mobile healthcare is a fusion of information technology and biotechnology and is a new type of health management service to keep people's health at anytime and anywhere without regard to time and space. The WBAN(Wireless Body Area Network) technology that collects bio signals and the data analysis and monitoring technology using mobile devices are essential for serving mobile healthcare. WBAN consisting of users with mobile devices meet another WBAN during movement, WBANs transmit data to the other media. Because of WBAN conflict, several nodes transmit data in same time slot so a collision will occur, resulting in the data transmission being failed and need more energy for re-transmission. In this thesis, we proposed a MAC protocol for WBAN with mobility to solve these problems. First, we proposed a superframe structure for WBAN. The proposed superframe consists of a TDMA(Time Division Muliple Access) based contention access phase with which a node can transmit data in its own time slot and a contention phase using CSMA/CA algorithm. Second, we proposed a network merging algorithm for conflicting WBAN based on the proposed MAC protocol. When a WBAN with mobility conflicts with other WBAN, data frame collision is reduced through network reestablishment. Simulations are performed using a Castalia based on the OMNeT++ network simulation framework to estimate the performance of the proposed superframe and algorithms. We estimated the performance of WBAN based on the proposed MAC protocol by comparing the performance of the WBAN based on IEEE 802.15.6. Performance evaluation results show that the packet transmission success rate and energy efficiency are improved by reducing the probability of collision using the proposed MAC protocol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.4
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• pp.477-484
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• 2008

For the effective use of the conger eel by-products, such as head and frame, Tang, which is the Korean-type soup, from conger eel by-products (TCEB) was developed and its food component characterization was compared with that of commercial Chueotang, loach Tang. According to the results of viable cells and coliform group of TCEB heated at $115^{\circ}C$ for various times, the reasonable $F_0$ value was 8 min. The proximate composition of TCEB was 90.7% for the moisture, 4.8% for the protein, 2.6% for the lipid, and 1.5% for the ash. The extractive-nitrogen content of TCEB was 243.1 mg/100 g, which was higher than that of commercial Chueotang, 208.0 mg/100 g. The total amino acid content of TCEB was 4,310 mg/100 g and its major amino acids were glutamic acid (637.3 mg/100 g, 14.8%), glycine (409.1 mg/100 g, 9.5%) and alanine (404.4 mg/100 g, 9.3%). TCEB was not felt in the sensual fish odor and its sensual taste was good. The health functional properties for health of TCEB were 1.29 as a PF (protection factor) for antioxidative activity and 39.4% for angiotensin Ⅰ converting enzyme (ACE) inhibiting activity.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.133-139
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• 2012

For the examination of nuclear medicine, myocardial scan is a good method to evaluate a hemodynamic importance of coronary heart disease. but, the automatized qualitative measurement is additionally necessary to improve the decoding efficiency. we suggests the creation of cardiac three-dimensional model and model of three-dimensional cardiac thickness as a new measurement. For the experiment, cardiac reduced cross section was obtained from SPECT. Next, the pre-process was performed and image segmentation was fulfilled by level set. for the modeling of left cardiac thickness, it was realized by applying difference equation of two-dimensional laplace equation. As the result of experiment, it was successful to measure internal wall and external wall and three-dimensional modeling was realized by coordinate. and, with laplace formula, it was successful to develop the thickness of cardiac wall. through the three-dimensional model, defects were observed easily and position of lesion was grasped rapidly by the revolution of model. The model which was developed as the support index of decoding will provide decoding information to doctor additionally and reduce the rate of false diagnosis as well as play a great role for diagnosing IHD early.

• Korean Security Journal
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• no.45
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• pp.129-159
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• 2015

The police do their best effort to make all security standards of competence and law enforcement suit the public's expectation, take precedence over the direction of the security policy to what the people want, and realize the Republic of Korea in which the people are happy with a strong police security. On the other hand. The people demand the fairly high level of moral integrity to the police who are in charge of law enforcement at the forefront than any other organization. Suggesting various measures for enhancing the organizational level of police ethics in police ethics awareness of police offices have been working on, yet the prevailing view that still insufficient. In this study, after analyzing the current moral status of the police, I suggest ways to improve as follows: First, strengthening the training and improving the program of police ethics. For this, securing professional teacher and implementation of customized ethics training are necessary. Second, the subject of human nature test should be expanded. The targets are limited to less than a supervisor. It should be expanded to all police officers. Third, the improvement of the organizational culture. For this, introduction of mentoring system and enlightening-oriented inspection is needed. Fourth, reducing the burden of manpower by reinforcing personnel. By defusing lack of police personnel, the police will be able to conduct intensive and effective ethics education. Finally, the provision of the stress relief measures for the police. To this end, the police requires constant efforts of the organization itself.

• Korean Security Journal
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• no.16
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• pp.81-99
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• 2008

Despite its legal, systematic and quantitative growth, Korean private security has not been showing satisfactory level of qualitative growth comparing to quantitative growth as it socially shocked with recent occurrence of the events and accidents. People on demand of security are making use of private security service to offset insufficient supply of security power as, especially, the incendiarism at Sungryemun last February brought out security issues for nationally important facilities and cultural assets, and other cases showed that the police would not cope with the appropriate security services under the current security system for protecting the life and property of people. For the supplementation of security power, the private security service is prevalent, but lots of service providers would not overcome its small business scale, except some large-sized security providers. There are some problem occurred as some providers employed staff who would not have the stuff for performing security service and they even committed illegal actions. Some opinions pointed out that it should come up with measures as they socially lose their credit. Therefore, this research suggests the recognition of the importance and the improvement measures of human resources management as follows. Security Service needs: 1. control of criteria for the employment/recruitment of human resources; 2. inducement of qualitative improvement of security service by ensuring excellent quality of human resources; 3. elevation of morale of organizational members with the operation of efficient promotion system; 4. introduction of professional certification system for the inflow of excellent quality of human resources.