• Title/Summary/Keyword: 열흐름

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On the (Un-)Possibility of a Labor Film in the Early Period of Democratization -A Study of Guro Arirang (민주화 초기 노동자 영화의 (불)가능성 -<구로아리랑> 연구)

  • Oh, Ja-Eun
    • Journal of Popular Narrative
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    • v.26 no.4
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    • pp.9-41
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    • 2020
  • Park Jong-won's debut film "Guro Arirang," based on a short story of the same title by Lee Moon-yeol, is the first commercial film to deal with labor struggles from a worker's point of view in the wake of the 1987 democratic movement, and a pioneering work in terms of representing female workers the Korean cinema has traditionally turned away from. In this film Park Jong-won tried to win the sympathy of the middle class for labor movement in spite of the red scare which still stood firm in the Korean society at that time. To convey its progressive message in a form acceptable to the middle class public, the film portrays labor issues in the light of universal humanity and ethics, not in terms of class hostility or struggle. Park Jong-won calls this point of view "common sense of normal people" and emphasizes its universality and objectivity. This study critically examines the cinematic strategies to deal with labor issues in a form acceptable to the public in a conventional and commercial film and the ideological implications of the "common sense of normal people" reflected in such strategies. The first chapter of the study reveals that the film destroys the irony of the original story and reduces the complex constellation of the characters to the conflict between pure good and evil, creating a melodramatic composition in which the good falls victim to evil. The tragedies suffered by the workers in the film are of course intended to arouse the audience's strong sympathy and solidarity with them. The second chapter shows that the film's various scenes and episodes converge on the them of compassion and grief, and are mostly based on cultural and real experiences and events that caused great public sensations at that time. Especially in the last decisive scene of the movie, the memory of the June 1987 uprising is strongly recalled. So "Guro Arirang" can be seen as a patchwork of proven cases of compassion and grief. The third chapter examines the implications of the scene where the workers turn back demands for wages and put the issues of human treatment and trust to the forefront at the crucial moment of their struggle. It appeals to universal moral values and sentiments that everyone has to acknowledge and removes the political dimension from the workers' campaign. While the film tends to become a pure story of humanity marginalizing irreconcilable conflicts of class interest, the workers fall to the position of passive victims who can be deeply sympathetic on the one hand, and on the other, are idealized as leaders with noble attitude keeping themselves aloof from the hard reality. As a result, the movie loses its realistic ground and weakens its narrative probability. The scenes reminiscent of the 1987 uprising which evoke the solidarity between working and middle class fail to integrate harmoniously into the whole story of the film and remain only as fragmentary parts of the patchwork of compassion and grief.

Development of heat exchanger by the utilization of underground water. I - Design for plat fin tube - (지하수 이용을 위한 열교환기 개발. I - 냉각핀의 설계제작 -)

  • Lee, W.Y.;Ahn, D.H.;Kim, S.C.;Park, W.P.;Kang, Y.G.;Kim, S.B.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.4 no.1
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    • pp.119-127
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    • 2002
  • This study was conducted to develop the heat exchanger by utilizing the heat energy of underground water(15℃), which might be used for cooling and heating system of the agricultural facilities. We developed the heat exchanger, parallel type plat fin tube made of Aluminum(Al 6063), which was named Aloo-Heat(No. of The registration design : 0247164, by Korean Intellectual property Office). The fin of exchanger was design of the granulated surface for minimizing fouling factor and dew forms, and also placed parallel to the tube in order to minimized the resistance of flows. 1. Aloo-heat was designed to have 0.03m for inside diameter, 0.036m for outside diameter of tube, 0.0012m for thickness of fin and 0.032m for length of plat fin. 2. t was also designed to have 1.5248m2/m for outside area of heat transfer, 0.0942m2/m for inside area contacting hot liquid, and the ratio (Ra) was 16.1869. 3. Efficiency of the fin was 93 percentage when fin length was 0.032m, and the fin thickness satisfied equation $\frac{h{\rho}}{k}$< 0.2 when it was 0.0012m. 4. According to the performance test of Aloo-heat, as the temperature and rate increased, the heating value also increased, heating value was 504kJ/h·m and 6,048kJ/h·m when it was 60℃, 10 𝑙/min and 80℃, 40 𝑙/min respectively. 5. The test of heating value was confident, because correlation value(R2) was 0.9898 for the temperature and 0.9721 for flow rate of hot liquid, respectively.

A Study on change in thermal properties and chemical structure of Zr-Ni delay system by aging (노화에 따른 Zr-Ni계 지연관의 열 특성 및 화학적 구조 변화에 관한 연구)

  • Park, Byung Chan;Chang, Il Ho;Kim, Sun Tae;Hwang, Taek Sung;Lee, Seungho
    • Analytical Science and Technology
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    • v.22 no.4
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    • pp.285-292
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    • 2009
  • It has been observed that, after long term storage, some ammunitions are misfired by tamping (combustionstopping) due to aging of the chemicals loaded in the ammunitions. Used in ammunitions are percussion powder which provides the initial energy, igniter which ignites the percussion powder, and a delay system that delays the combustion for a period of time. The percussion powder is loaded first, followed by the igniter and then the delay system, and the ammunitions explode by the energy being transferred in the same order. Tamping occurs by combustion-stopping of the igniter or insufficient energy transfer from the igniter to the delay system or the combustion-stopping of the delay system, which are suspected to be caused by low purity of the components, inappropriate mixing ratio, size distribution of particulate components, type of the binder, blending method, hydrolysis by the humidity penetrated during the long term storage, and chemical changes of the components by high temperature. Goal of this study is to find the causes of the combustion-stopping of the igniter and the delay system of the ammunitions after long term storage. In this study, a method was developed for testing of the combustion-stopping, and the size distributions of the particulate components were analyzed with field-flow fractionation (FFF), and then the mechanism of chemical change during long term storage was investigated by thermal analysis (differential scanning calorimetry), XRD (X-ray diffractometry), and XPS (X-ray photoelectron spectroscopy). For the ignition system, M (metal)-O (oxygen) and M-OH peaks were observed at the oxygen's 1s position in the XPS spectrum. It was also found by XRD that $Fe_3O_4$ was produced. Thus it can be concluded that the combustion-stopping is caused by reduction in energy due to oxidation of the igniter.

Partial Oxidation of Methane to $H_2$ Over Pd/Ti-SPK and Pd/Zr-SPK Catalysts and Characterization (Pd/Ti-SPK과 Pd/Zr-SPK 촉매상에서 수소 생산을 위한 메탄의 부분산화반응과 촉매의 특성화)

  • Seo, Ho-Joon;Kang, Ung-Il
    • Applied Chemistry for Engineering
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    • v.21 no.6
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    • pp.648-652
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    • 2010
  • Catalytic activities of the partial oxidation of methane (POM) to hydrogen were investigated over Pd(5)/Ti-SPK and Pd(5)/Zr-SPK in a fixed bed flow reactor (FBFR) under atmosphere, and the catalysts were characterized by BET, XPS, XRD. The BET surface areas, pore volume and pore width of Horvath-Kawaze, micro pore area and volume of t-plot of Pd(5)/Ti-SPK and Pd(5)/Zr-SPK were $284m^2/g$, $0.233cm^3/g$, 3.9 nm, $30m^2/g$, $0.015cm^3/g$ and $396m^2/g$, $0.324cm^3/g$, 3.7nm, $119m^2/g$, $0.055cm^3/g$, repectively. The nitrogen adsorption isotherms were type IV with hysteresis. XPS showed that Si 2p and O 1s core electronlevels of Ti-SPK and Zr-SPK substituted Ti and Zr shifted to slightly lower binding energies than SPK. The oxidation states of Pd on the surface of catalysts were $Pd^0$ and $Pd^{+2}$. XRD patterns showed that crystal structures of fresh catalyst changed amorphous into crystal phase after reaction. The conversion and selectivity of POM to hydrogen over Pd(5)/Ti-SPK and Pd(5)/Zr-SPK were 77, 84% and 78, 72%, respectively, at 973 K, $CH_4/O_2$ = 2, GHSV = $8.4{\times}10^4mL/g_{cat}{\cdot}h$ and were kept constant even after 3 days in stream. These results confirm superior activity, thermal stability, and physicochemical properties of catalyst in POM to hydrogen.

Rewetting Strategies for the Drained Tropical Peatlands in Indonesia (인도네시아의 배수된 열대 이탄지에 대한 재습지화 전략)

  • Roh, Yujin;Kim, Seongjun;Han, Seung Hyun;Lee, Jongyeol;Son, Yowhan
    • Korean Journal of Environmental Biology
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    • v.36 no.1
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    • pp.33-42
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    • 2018
  • The tropical peatlands have been deforested and converted to agricultural and plantation areas in Indonesia. To manage water levels and increase the overall productivity of crops, canals have been constructed in tropical peatlands. The canals destructed the structure of the tropical peatlands, and increased the subsidence and fire hazard risks in the region. The Indonesian government enacted regulations and a moratorium on tropical peatlands, in order to reduce degradation. A practical method under the regulations of rewetting tropical peatlands was to permit a canal blocking. In this study, four canal blocking projects were investigated regarding their planning, construction priority, design, building material, construction, monitoring, time and costs associated with the canal blockings. In the protected areas, regulations restricted the development of the tropical peatlands areas that were noted as deeper than 3 m, and the administration stopped issuing new concessions for future work projects for this noted criteria of land use. A noted purpose of canal blockings in these areas was to effectuate the restoration of the lands in the region. The main considerations of the restoration efforts were to maintain a durability of the blockings, and to encourage the participation of the area stakeholders. In the case of a concession area, regulations were set into place to restrict clear-cutting and shifting cultivation, and to maintain groundwater level in the tropical peatland. The most significant priorities identified in the canal blocking project were the efficiency and cost-effectiveness of the project. Nevertheless, the drainage of tropical peatlands has been continued. On the basis of a literature review on regulations and rewetting methods in tropical peatlands of Indonesia, we discussed the improvements of the regulations, and adequate canal blockings to serve the function to rewet the tropical peatlands in Indonesia. Our results would help establishing an adequate direction and recommended guideline on viable rewetting methods for the restoration of drained tropical peatlands in Southeast Asia.

Effect of Processing Additives on Vulcanization and Properties of EPDM Rubber (EPDM 고무의 첨가제에 따른 가류 및 물성에 미치는 영향 연구)

  • Lee, Soo;Bae, Joung Su
    • Journal of the Korean Applied Science and Technology
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    • v.35 no.1
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    • pp.173-185
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    • 2018
  • Effects of three different types of dispersions and flow improving additives composed with fatty acid esters, fatty acid metal salts and amide compound on the vulcanization and the mechanical properties properties of rubber compounds of EPDM and carbon black as fillers. were investigated using Mooney viscometer, moving die rheometer, hardness tester, and universal test machine. The aging characteristics of vulcanized EPDM compounds were also investigated. The Mooney viscosity measured at $125^{\circ}C$ showed a tendency to decrease in the order of amide type> metal salt type > ester type additive. Scorch time showed little or no difference with the addition of ester or metal salt type additives, but the amide type additive shortened a scorch time more than one minute. Rheological measurement data obtained at $160^{\circ}C$ showed that the vulcanization time was faster for metal salt type and amide type additive systems. Delta torque values of EPDM compound increased with metal salt type and amide type additives, but slightly decreased with ester type additive. The tensile strength of the EPDM compound was greatly improved when an ester type additive was added, but the amide type or metal salt type additive had no significant effect. The elongation was significantly improved for metal salt type additive, while the rest were not significantly affected. The tear strength of the EPDM compounds increased with the addition of all kinds of additives, and it increased remarkably in the case of metal salt type additive. Hardness of the EPDM compounds was nearly same value regardless of additive types. The thermal aging of the EPDM blend at $100^{\circ}C$ for 24 h showed little change in the case of metal salt type or amide type additive, but the elongation tends to decrease by 10-20% for all EPDM compounds containing additives.

Energy Budgets for the Developmental Stages of Palaemon macrodactylus (Palaemon macrodactylus의 생활사에 따른 에너지 수지)

  • CHIN Pyung;KIM Heung-Yun;SIN Yun-Kyong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.5
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    • pp.341-358
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    • 1992
  • In order to estimate energy budgets of Palaemon macrodactylus, larvae of the shrimp were reared in the laboratory at constant conditions $(25^{\circ}C: 31-32\%o),$ and then juvenile to adult of the shrimp were reared at $15^{\circ}C\;and\;25^{\circ}C$ in the laboratory. Energy used by the reared shrimps were calculated from estimates of data on feeding, growth, molting, metabolism, nitrogen excretion, and energy content. Juveniles and adults reared in the laboratory, which fed on Artemia nauplii, had an average daily growth rates of 0.079 mm/day at $15^{\circ}C\;and\;of\;0.122mm/day\;at\;25^{\circ}C$. The average growth factor* of P. macrodactylus males and females ranged from $3.2\%$ for adult to $13.2\%$ for juveniles individuals, respectively. Intermolt periods were related to body size of the shrimp and to temperature. Average laboratory growth curves were calculated from data on growth factors and intermolt periods to body size of the shrimp at $15^{\circ}C\;and\;25^{\circ}C$. The calorie contents of the shrimp, their molts, eggs and larvae were determined by biochemical composition and oxygen bomb calorimetry. The average amount of energy used in growth for larvae and juvenile to adult were 4.94 cal and 4.55 cal per dry weight in milligram, respectively. The ammount of oxygen used in metabolism was calculated from size, temperature-specific respiration rate. To convert the ammount of oxygen used in respiration into the equivalent energy lost heat was estimated from the data on chemical composition for the larvae and adult, the values was 4.58 cal/ml $O_2$. The energy content per egg was 0.078 cal. The assimilation efficiency estimated by nitrogen content of food and egested faeces gave $61.5\%$ for the larvae. The efficiencies for juvenile to adult ranged between $79.4\%$ and $90.1\%$ The gross growth efficiencies $(K_1)$ and net growth efficiencies $(K_2)$ of P macrodactylus showed $18.33\%\;and 32.63\%$ for total larval stages, ranged from $21.30\%\;to\;31.04\%\;and\;from\;30.03\%\;to\;39.34\%$ for juvenile to adult, respectively.

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Effects of Mn- and K-addition on Catalytic Activity of Calcium Oxide for Methane Activation (메탄 활성화반응에서 산화칼슘 촉매의 활성에 대한 망간과 칼륨의 첨가효과)

  • Park, Jong Sik;Kong, Jang Il;Jun, Jong Ho;Lee, Sung Han
    • Journal of the Korean Chemical Society
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    • v.42 no.6
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    • pp.618-628
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    • 1998
  • Pure CaO, Mn-doped CaO, Mn/CaO, and K/CaO catalysts were prepared and tested as catalysts for the oxidative coupling of methane in the temperature range of 600 to 800$^{\circ}C$ to investigate the effects of Mn- and K-addition on the catalytic activity of calcium oxide. To characterize the catalysts, X-ray powder diffraction(XRD), XPS, SEM, DSC, and TG analyses were performed. The catalytic reaction was carried out in a single-pass flow reactor using on-line gas chromatography system. Normalized reaction conditions were generally $p(CH_4)/p(O_2)=250$ Torr/50 Torr, total feed flow rate=30 mL/min, and 1 atm of total pressure with He being used as diluent gas. Among the catalysts tested, 6.3 mol% Mn-doped CaO catalyst showed the best $C_2$ yield of 8.0% with a selectivity of 43.2% at 775$^{\circ}C$. The $C_2$ selectivity increased on lightly doped CaO catalysts, while decreased on heavily doped CaO([Mn] > 6.3 mol%) catalysts. 6 wt.% Mn/CaO and 6 wt.% K/CaO catalysts showed the $C_2$ selectivities of 13.2% and 30.9%, respectively, for the reaction. Electrical conductivities of CaO and Mn-doped CaO were measured in the temperature range of 500 to 1000$^{\circ}C$ at Po2's of $10^{-3}\; to\;10^{-1}\;atm.$ The electrical conductivity was decreased with Mn-doping and increased with increasing $P0_2$in the range of $10^{-3}\;to\;10^{-1}\;atm,$ indicating the specimens to be p-type semiconductors. It was suggested that the interstitial oxygen ions formed near the surface can activate methane and the formation of interstitial oxygen ions was discussed on the basis of solid-state chemistry.

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EFFECT OF ULTRASONIC VIBRATION ON ENAMEL AND DENTIN BOND STRENGTH AND RESIN INFILTRATION IN ALL-IN-ONE ADHESIVE SYSTEMS (All-in-one 접착제에서 초음파진동이 법랑질과 상아질의 결합강도와 레진침투에 미치는 영향)

  • Lee, Bum-Eui;Jang, Ki-Taeg;Lee, Sang-Hoon;Kim, Chong-Chul;Hahn, Se-Hyun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.1
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    • pp.66-78
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    • 2004
  • The objective of this study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration in enamel and dentin achieved with those gained using the conventional technique and vibration technique. For enamel specimens, thirty teeth were sectioned mesio-distally. Sectioned two parts were assigned to same adhesive system but different treatment(vibration vs. non-vibration). Each specimen was embedded in 1-inch inner diameter PVC pipe with a acrylic resin. The buccal and lingual surfaces were placed so that the tooth and the embedding medium were at the same level. The samples were subsequently polished silicon carbide abrasive papers. Each adhesive system was applied according to its manufacture's instruction. Vibration groups were additionally vibrated for 15 seconds before curing. For dentin specimen, except removing the coronal part and placing occlusal surface at the mold level, the remaining procedures were same as enamel specimen. Resin composite(Z250. 3M. U.S.A.) was condensed on to the prepared surface in two increments using a mold kit(Ultradent Inc., U.S.A.). Each increments was light cured for 40 seconds. After 24 hours in tap water at room temperature, the specimens were thermocycled for 1000cycles. Shear bond strengths were measured with a universal testing machine(Instron 4465, England). To investigate infiltration patterns of adhesive materials, the surface of specimens was examined with scanning electron microscope. The results were as follows: 1. In enamel the mean values of shear bond strengths in vibration groups(group 2, 4, 6) were greater than those of non-vibration group(group 1, 3, 5). The differences were statistically significant except AQ bond group. 2. In dentin, the mean values of shear bond strengths in vibration groups(group 2, 4, 6) were greater than those of non-vibration groups(group 1, 3, 5). But the differences were not statistically significant except One-Up Bond F group. 3. The vibration group showed more mineral loss in enamel and longer resin tag and greater number of lateral branches in dentin under SEM examination.

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A STUDY OF ADDITIONAL VIBRATION EFFECT ON DENTIN BOND STRENGTH (진동이 상아질 결합력에 미치는 영향에 관한 연구)

  • Lee, Jin;Kim, Jung-Wook;Lee, Sang-Hoon;Kim, Chong-Chul
    • Journal of the korean academy of Pediatric Dentistry
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    • v.29 no.4
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    • pp.632-640
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    • 2002
  • The objective of the study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration into dentinal tubules achieved with those gained using the conventional technique. Eighty-eight noncarious extracted human permanent molar teeth were sectioned to remove the coronal enamel and were embedded in 1-inch PVC pipe with acrylic resin. The occlusal surfaces were placed so that the tooth and the embedding medium were at the same level to form one flat surface, and the samples were subsequently polished with silicon carbide abrasive papers. The samples were randomly assigned to 4 groups(n=22). On Group 1 and 2, Single Bond(3M-ESPE, St. Paul, USA) was used, and on Group 3 and 4, One-Step(Bisco Inc., Schaumburg, USA) was used, and each was applied according to its manufacturer's instructions. For Group 2 and Group 4, vibration was applied with ultrasonic scaler for 10 seconds, and the adhesive was light-cured for 10 seconds. Resin composite was condensed on to the prepared surface in two increments using a mold kit(Ultradent Products Inc., USA) and each was light-cured for 40 seconds. After 24 hours in tap water at room temperature the specimens were thermocycled, and shear bond strengths were measured with a universal testing machine(Instron 4465, Canton, USA). To investigate infiltration patterns of the adhesive materials, the surface of specimen was examined with scanning electron microscope. The results were as follows. 1. The shear bond strengths of vibration groups(Group 2, Group 4) were significantly greater than those of the non-vibration groups(Group 1, Group 3)(p<0.05). 2. The shear bond strengths of Single Bond and One-Step were not significantly different (p>0.05). 3. The vibration groups showed greater number of resin tags in tubules and lateral branches under SEM.

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