• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.270-274
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• 2017

Formic acid has been known as one of key sources of hydrogen. Among various monometallic catalysts, hydrogen can be efficiently produced on Pd catalyst. However, the catalytic activity of Pd is gradually reduced by the blocking of active sites by CO, which is formed from the unwanted indirect oxidation of formic acid. One of promising solutions to overcome such issue is the design of alloy catalyst by adding other metal into Pd since alloying effect (such as ligand and strain effect) can increase the chance to mitigate CO poisoning issue. In this study, we have investigated formic acid deposition on the bimetallic $Pd/Pd_3Fe$ core-shell nanocatalyst using DFT (density functional theory) calculation. In comparison to Pd catalyst, the activation energy of formic acid dehydrogenation is greatly reduced on $Pd/Pd_3Fe$ catalyst. In order to understand the importance of alloying effects in catalysis, we decoupled the strain effect from ligand effect. We found that both strain effect and ligand effect reduced the binding energy of HCOO by 0.03 eV and 0.29 eV, respectively, compared to the pure Pd case. Our DFT analysis of electronic structure suggested that such decrease of HCOO binding energy is related to the dramatic reduction of density of state near the fermi level.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.496-502
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• 2015

Hydrocarbon dew point(HCDP), a property which is the most generally used for describing natural gas condensation, is a very important parameter of natural gas quality specifications. HCDP is strongly influenced by the concentration of the heavier hydrocarbon components, especially $C_6+$, so, along with compliance with gas quality specifications, build up of procedures for obtaining accurate HCDP is essential for gas transmission company, because hydrocarbon condensation present may cause serious operational and safety problems. This study has been carried out in an attempt to measure HCDP accurately by the automatic hydrocarbon dew point meter under the actual field conditions. Measured HCDP also has been compared with calculated HCDP using the composition determined by gas chromatograph and industry accepted equation of state at multiple pressures, along with the cricondentherm. The test results are 1) the automatic hydrocarbon dew point meter was able to measure stable HCDP continuously 2) the automatic hydrocarbon dew point meter has been performed reference measurement by pure propane with a known dew point from literature, and 3) A meaningful differences was observed when comparing the automatic hydrocarbon dew point meter and gas chromatograph results for synthetic standard gas mixtures and real gas mixtures.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.4
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• pp.292-296
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• 2000

Mechenochemical reaction by planetary type ball mill is applied to prepare $Sm_2$$Fe_{17}$$N_{x}$ permanent magnet powders. Starting from pure samarium and iron powders, the formation process of hard magnetic $Sm_2$$Fe_{17}$$N_{x}$ phase by ball milling and a subsequent solid state reaction were studied. At as-milled stage powders were found to consist of amorphous Sm-Fe and $\alpha$-Fe phases in all composition of $Sm_2$$Fe_{100-x}$(x = 11, 13, 15). The dependence of starting composition of elemental powder on the formation of Sm-Fe intermetallic compound was investigated by heat treatment of as-milled powders. When Sm concentration was 15 at%, heat-treated powder consists of mostly $Sm_2$$Fe_{17}$$N_{x}$single phase. For synthesizing of hard magnetic $Sm_2$$Fe_{17}$$N_{x}$ compound, additional nitriding treatment was carried out under $N_2$gas atmosphere at $450^{\circ}C$. The increase in the coercivity and remanence was parallel to the nitrogen content which increased drastically at first and then gradually as the nitriding time was extended. The ball-milled Sm-Fe-N powders were expected to be prospective materials for synthesizing of permanent magnet with high performance.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.6 no.1
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• pp.133-160
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• 1984

The main purpose of the present study is to survey the major abstracting bulletins of national nature in Korea, to define such problem areas as lacunae, duplicates and limitation in coverage in the abstracting services currently available in Korea, and to make some suggestions for action for improving the abstracting services in the light of general principles and the tradition and situations unique to Korea. The major conclusions reached at this study are summarised as follows: (A) A new abstracting bulletin of general nature covering the whole field needs to be created in each of the following fields where no established abstracting service is available for the outcome of research and development activities in Korea. (1) Language (2) Religion (3) Art (4) Language (5) Literature (6) History (B) A new specialised abstracting bulletin needs to be created in each of the following fields of science where abstracting services limited in coverage are partially available. (a) Statistics (b) Sociology (c) political science (d) Public administration (e) Law (f) Folk lore (g) Military science (2) Pure sciences (a) Mathematics (b) Chemistry (c) Astronomy (d) Geology (e) Mineralogy (f) Life sciences (g) Botany (h) Zoology (3) Applied sciences (a) Agriculture (b) Architectural engineering (c) Mechanical engineering (d) Electrical engineering (e) Chemical engineering (f) Manufacturing industry (g) Domestic science (C) Publication of the abstracting bulletins suggested in (A) and (B) above may be ideally carried on by a qualified learned society established in the respective field. and should be financially supported by the public fund under the provisions of Art. 27 of the Research Promotion Act of 1979. (D) The current practice of adding the author's abstract and keywords to each of the records of the "Doctoral Theses in Humanities and Social Sciences" part of the" Catalogue of Doctoral and Master's Theses Submitted to the Universities in Korea" published by the National Assembly Library should be applied to all the other parts, i. e. to the parts of the "Master's Theses in Humanities and Social Sciences" and of the "Doctoral and Master's Theses in Natural Sciences': which will not only increase the Catalogue's use value but also discourage appearance of various theses abstracts of individual academic institutions such as the" Abstracts of the Doctoral and Master's Theses Submitted to Korea Advanced Institute of Science and Technology" which will in turn reduce inefficiency involved in the abstracting services at national level. (E) A general abstracting bulletin covering most part of the outcome of research and development activities in Korea other than that covered by the existing abstracts needs to be created to be temporarily. used till the abstracting journals suggested in this study will be fully available. A realistic way of having such a bulletin may be to expand the present coverage of "The Abstracts of the Reports of the Government-sponsored Projects" currently published by Korean Research Foundation.

• Resources Recycling
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• v.18 no.1
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• pp.38-43
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• 2009

In this study, binderless consolidation processes of ultra foe Si powder, by-products of making high purity poly-Si in the current method, were systematically investigated for use as economical solar-grade feedstock. The average diameter of the silicon powder was $7.8{\mu}m$. The main contaminants of the fine silicon powder were $SiO_2$ type oxide and humidity. The chemical pretreatment using the HF solution was observed to be effective for the improvement of the compactability of the silicon powder and the density ratio and the strength of the silicon powder compacts. The yield of the binder-free consolidation process increased by 20% under a vacuum condition. In as-received state, the silicon powder were not pure enough to be used as solar grade feed-stock material. After the dry chemical treatments, a sufficiently high purity above solar-grade was able to be achieved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.464-469
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• 2019

A remote monitoring panel and control system was developed to control various valves and access control chambers, including gas shutoff valves used in CBR(Chemical, Biological and Radiological) facilities. The remote monitoring panel consisted of a main panel installed in the NBC (Nuclear, Biological and Chemical) control room and auxiliary panel installed in the clean room, and the size was divided into pure control and control including CCTV. This system can be monitored and controlled remotely according to the situation where an explosion door and gas barrier door can occur during war and during normal times. This system is divided into normal mode and war mode. In particular, it periodically senses the operation status of various valves, sensors, and filters in the CBR facilities to determine if each apparatus and equipment is in normal operation, and remotely alerts situation workers when repair or replacement is necessary. Damage due to the abnormal operation of each device in the situation can be prevented. This enables control of the blower, supply and exhaust damper, emergency generator, and coolant pump according to the state of shutoff valve and positive pressure valve in the occurrence of NBC, and prevents damage caused by abrupt inflow of conventional weapons and nuclear explosions.

• Korean Journal of Heritage: History & Science
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• v.47 no.3
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• pp.172-187
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• 2014

The purpose of this paper is to examine how the 'tradition' has been identified and used concretely on the protection system of cultural property. Firstly, this paper investigated the historical process and aspects that the 'cultural property' and the 'tradition' combined, each had different meaning at the beginning. And it investigated the linkage of them which effect to the protection system and to each other on the system operated. Then, it pointed out a rift within the discourse of tradition to which the system have held on, and the problems as its result. This paper applied the viewpoint of anti-essentialism that the tradition is presented with hegemonic act to raise the inevitable continuity with the past, instead of the common notion that the tradition is 'everything that is handed down from the past.' Because the cultural property is the product of the state system, to pursne the linkage of it and the tradition is identical to examine how the tradition have been officially defined in the national hegemony. Since the 1920s the tradition has defined as a fixed, essential, pure reality in the changing process of the protection system of cultural property. This essentialist viewpoint about the tradition have been continued as the institutional premise regardless of many critics, raised by studies focusing on the culture and cultural property. But we see now a rift on the discourse of tradition as the intellectual discourse has been supported to the system, that is caused by the fast-changing global economic environment and a rat race around the registration of intangible cultural heritage of UNESCO.

• The Journal of Korean Philosophical History
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• no.39
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• pp.143-168
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• 2013

The purpose of this paper is to study the succession and method of five-masters of southern school in transmitting the internal alchemy in Taoism which is established by Zhang Bo-duan. In history, the internal alchemy is divided into a few schools but all of them are under the umbrella of Zhang Bo-duan's alchemy. The five master's method has been consistent from Zhang Bo-duan to Seok Tae to Seol Do Gwang based on three reasons. First, they lived long while practicing the method. Second, they learned the method from their direct master secretly. Third, they kept practicing the individual method while staying in the secular world rather than in a religious body. I limit three of them Zhang Bo-Dan, Seok Tae, Seol Do Gwang as figures who practiced the pure internal alchemy. Thus I argue that the method stayed only for 200 years, arising from the late Dang Dynasty and disappearing in 1911, when Seol Do-Gwang was dead. This method can be instructed only to the appropriate figure, and the specific steps of method are taught through the oral instruction so that this method cannot be wide spread. Based on the fact that the time of practicing method is quite long and it needs intensive and constant efforts, it is difficult for a mundane person to practice and cope with the training. Jin Nam and Baek Ok Seom are believed that they belonged to the school of Shin So. Baek Ok Seom is regarded as a figure that made efforts to unite the school of Wei and the internal alchemy. However, he made lots of fabrication and discrepancy. Thus I state that Jin Nam and Baek Ok Seom need to be out in the succession and method of five masters of southern school in Taoism. Their changed method in quality needs to be organized in a new genealogy.

• Journal of agricultural medicine and community health
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• v.48 no.1
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• pp.41-49
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• 2023

Objectives: To obtain audiologic basic data to diagnose the noise induced hearing loss of workers in fisheries. Methods: The charts of the referred fishermen with noise induced hearing loss from November 2022 to February 2023 at a general hospital were retrospectively reviewed. Pure tone audiometry, speech audiometry, auditory brainstem response test and auditory steady state response test were conducted. Results: All of them were men over 60 years of age, and the average duration of exposure to noise was 38.9 ± 10.8 years, and the average symptom duration of hearing loss was 13.4 ± 4.3 years. Although the hearing thresholds in the high frequencies were higher than thresholds in the low frequencies, the audiogram showed a down-sloping pattern without rebound at 8 kHz. 10.5% of the cases had thresholds greater than 75 dB in high frequencies, but 57.9% had thresholds greater than 40 dB in low frequencies. Other hearing test results of fishermen were similar to those of general noise-induced hearing loss. Conclusions: Although the fishermen were exposed to noise for a long time, they recognized hearing loss late. The hearing threshold in lower frequencies of the fishermen was higher than expected. Further studies will be needed to analyze the audiologic characteristics of noise-induced hearing loss of the fishermen after confirming noise exposure by conducting a survey on the working environment, such as the noise level and working hours.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.620-626
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• 2015

$Ho^{3+}$ doped $SrAl_2O_4$ upconversion phosphor powders were synthesized by spray pyrolysis, and the crystallographic properties and luminescence characteristics were examined by varying activator concentrations and heattreatment temperatures. The effect of organic additives on the crystal structure and luminescent properties was also investigated. $SrAl_2O_4:Ho^{3+}$ powders showed intensive green emission due to the $^5F_4/^5S_2{\rightarrow}^5I_8$ transition of $Ho^{3+}$. The optimal $Ho^{3+}$ concentration in order to achieve the highest luminescence was 0.1%. Over this concentration, emission intensities were largely diminished via a concentration quenching due to dipole-dipole interaction between activator ions. According to the dependence of emission intensity on the pumping power of a laser diode, it was clear that the upconversion of $SrAl_2O_4:Ho^{3+}$ occurred via the ground state absorption-excited state absorption processes involving two near-IR photons. Synthesized powders were monoclinic as a major phase, having some hexagonal phase. The increase of heat-treatment temperatures from $1000^{\circ}C$ to $1350^{\circ}C$ led to crystallinity enhancement of monoclinic phase, reducing hexagonal phase. The hexagonal phase, however, did not disappear even at $1350^{\circ}C$. When both citric acid (CA) and ethylene glycol (EG) were added to the spray solution, the resulting powders had pure monoclinic phase without forming hexagonal phase, and led to largely enhancement of crystallinity. Also, N,N-Dimethylformamide (DMF) addition to the spray solution containing both CA and EG made it possible to effectively reduce the surface area of $SrAl_2O_4:Ho^{3+}$ powders. Consequently, the $SrAl_2O_4:Ho^{3+}$ powders prepared by using the spray solution containing CA/EG/DMF mixture as the organic additives showed about 168% improved luminescence compared to the phosphor prepared without organic additives. It was concluded that both the increased crystallinity of high-purity monoclinic phase and the decrease of surface area were attributed to the large enhancement of upconversion luminescence.