• Title/Summary/Keyword: Neutral behavior

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Analysis on the Generation Characteristics of $^{14}C$ in PHWR and the Adsorption and Desorption Behavior of $^{14}C$ onto ion Exchange Resin (중수로 원전$^{14}C$ 발생 특성 및 이온교환수지에 의한 $^{14}C$$\cdot$착탈 거동 분석)

  • 이상진;양호연;김경덕
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.06a
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    • pp.147-157
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    • 2004
  • The production of $^{14}C$ occurs in the Moderator(MOD), Primary Heat Transport System (PHTS), Annulus Gas System(AGS) and Fuel in the CANDU reactor. Among the four systems, The MOD system is the largest contributor to $^{14}C$ production(approximately 94.8%). $^{14}C$ is distributed of $^{14}CO_2$, $H_2^{14}CO_3$, $H^{14}{CO_3}^-$ and $^{14}{CO_3}^{2-}$ species as a function of the pH of water. Of these species, $H_2^{14}CO_3$ and $H^{14}{CO_3}^-$ form are predominant because the pH of MOD system is > 5. In this paper, adsorption-desorption characteristics of bicarbonate ion (${HCO_3}^-$) by IRN 150 resin was investigated. ${HCO_3}^-$ ion existed in neutral condition(app. pH 7)was reacted with ion exchange resin (IRN-150) and saturated with it. Then $NaNO_3$ and $Na_3PO_4$ solutions selected as extraction materials were used to make an investigation into feasibility of ${HCO_3}^-$ extraction from resin saturated with ${HCO_3}^-$. Desorption of $CO^{2+}$ and $Cs^+$ ion by $Na^+$ ion was not occurred, and desorption of ${HCO_3}^-$ ion by ${NO_3}^-$ and ${PO_4}^{3-}$ was occurred slowly. Also, the status of ion exchange which is used in Wolsong NPPs and generation of spent resin yearly were surveyed.

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Formation of Complex Between Polyelectrolytes and pH/Temperature Sensitive Copolymers (고분자전해질과 pH/온도감응성 고분자 사이의 복합체 형성에 관한 연구)

  • Yoo, Mi Kyong;Sung, Yong Kiel
    • Journal of the Korean Chemical Society
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    • v.42 no.1
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    • pp.84-91
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    • 1998
  • Random copolymers of N-isopropyl acrylamide (NIPAAm) and acrylic acid (AAc) which exhibit temperature- and pH-responsive behavior were synthesized by free-radical polymerization. The copolymers were characterized by means of FT-IR spectrometry and titration. The influence of polyelectrolyte on the lower critical solution temperature (LCST) of pH/temperature-sensitive polymers was investigated in the pH range of 2-12. The LCSTs of PNIPAAm/water in poly(NIPAAm-co-AAc) were determined by cloud-point measurements. A polyelectrolyte complex was prepared by mixing poly(NIPAAm-co-AAc) with poly(allylamine) (PAA) or poly(L-lysine) (PLL) solutions as anionic and cationic polyelectrolytes, respectively. Back titration was performed to determine the content of AAc and to study the effect of comonomer ionization on the LCST. The LCSTs of PNIPAAm/water in the copolymers were strongly affected by pH, presence of polyelectrolyte, AAc content, and charge density on the polymer. The polyelectrolyte complexes were formed at neutral condition. The influence of more hydrophobic PLL as polyelectrolyte on the cloud-point of PNIPAAm/water in the copolymer was stronger than that of poly(allylamine) (PAA).

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LONGITUDINAL AND SEASONAL VARIATIONS OF THE ELECTRON TEMPERATURE AND DENSITY IN THE LOW_LATITUDE TOPSIDE IONOSPHERE OBSERVED BY KOMPSAT-1 (다목적 실용위성 1호로 측정한 저위도 상부 이온층의 전자 온도와 전자 밀도의 경도 및 계절별 변화)

  • Kim, Hee-jun;Park, Sun-Mie;Lee, Jae-Jin;Lee, En-sang;Min, Kyoung-Wook;Han, Won-yong;Nam, Uk-Won;Jin, Ho
    • Journal of Astronomy and Space Sciences
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    • v.19 no.2
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    • pp.123-132
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    • 2002
  • The electron density and temperature in the topside ionosphere are observed by the ionosphere Measurement Sensor (IMS) onboard the KOMPSAT-1, which has the sun-synchronous orbit of the altitude of 685 km and the orbital inclination of $98^{\circ}$ with a descending node at 22:50LT. Observations have been analyzed to determine the seasonal variations of the electron density and temperature in the low-latitude region. Only the night-time (22:50LT) behavior on magnetically quiet days (Kp < 4) has been examined. Observations show a strong longitudinal and seasonal variation. Generally, in the dip equator the density increases and the temperature decreases. In equinox the latitudinal distributions of the electron density and temperature are quite symmetric about the dip equator. However, the local maximum of the density and the local minimum of the temperature shift toward the Northern hemisphere in summer solstice but the Southern hemisphere in winter solstice. Such variations are due to the influences of field-aligned plasma transport induced by F region neutral wind. Compared with the IRI95 model, the observed electron density and temperature show significant differences from those predicted by the IRI95 model.

Chemical Composition of Rainwater in Chonju-city, Korea (전주시에서 채수된 강수의 화학적 조성)

  • 나춘기;정재일
    • Journal of Korean Society for Atmospheric Environment
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    • v.13 no.5
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    • pp.371-381
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    • 1997
  • Precipitation sampls were collected in Chonju-city during October 1994 to September 1995 and were analysed for major ions (N $a^{+}$, $K^{+}$, $Ca^{2+}$, $Mg^{2+}$, C $l^{[-10]}$ , NO/$_3$, S $O_4$$^{2-}$) and trace metals (Al, Cd, Ni, Pb, Sr, Zn) in addition to pH, in order to understand the chemical characteristics of acid rain and to estimate the origin of the determined ions. Most rain showed a neutral or alkaline character, and only 35% had a pH lower than 5.6. S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ are identified as the primary contributors to precipitation acidity in this region. Neutralization of precipitation acidity occurs as a result of the dissolution of alkaline compounds containing $Ca^{2+}$, $Mg^{2+}$ and $K^{+}$. S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ precipitation concentrations exhibit a seasonal pattern in which higher concentrations are observed during spring months and lower concentrations during summer months. However, the seasonal behavior of $H^{+}$ concentrations differs from this pattern, in that the highest concentrations occur during autumn months, owing to the different influence of neutralization processes. In all rain, S $O_4$$^{2-}$ concentration exceeded NO/$_3$$^{[-10]}$ concentration. The contribution of maritime sources to the total S $O_4$$^{2-}$ concentration was very low or negligible. For rain strongly affacted by yellow sand, $Ca^{2+}$, $Mg^{2+}$ and $K^{+}$ ions show a sharp increase in concentration, reflecting the increased amount of dust and soil suspended in atmosphere. At the same time, S $O_4$$^{2-}$ and N $O_3$$^{[-10]}$ concentrations are at their highest levels while $H^{+}$ values are not comparably elevated, presumably beacause much of the acidity has been neutralized by alkaline substances. The seasonal variance of trace metal concentrations in rainwater is similar to that of major cations. The annual wet flux of acidic pollutants and trace metals wat calculated to be as follows: N $O_3$$^{[-10]}$ ; 2.32 g/$m^2$, S $O_4$$^{2-}$, 5.34 g/$m^2$, Al; 6.30 mg/$m^2$, Cd; 0.62 mg/$m^2$, Ni; 4.08 mg/$m^2$, Pb: 9.76 mg/$m^2$, Sr; 5.94 mg/$m^2$, Zn; 111 mg/$m^2$./$m^2$.

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Numerical Study on Shotcrete Lining with Steel Reinforcement Using a Fiber Section Element (화이버 단면 요소를 이용한 강재 보강된 숏크리트 라이닝의 수치해석적 연구)

  • Kim, Jeong Soo;Yu, Jee Hwan;Kim, Moon Kyum
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.3
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    • pp.919-930
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    • 2014
  • In this study, the load capacities and behaviors of a shotcrete member with steel supports, as composite member, are investigated numerically by using a fiber section element. The cross section of a shotcrete lining with steel support is divided into a bundle of fibers, which are allocated nonlinear stress-strain relations and used for determining internal forces. To verify the used approach of the finite element method for shotcrete with steel supports, the load-displacement relations of shotcrete lining obtained by numerical analysis are compared with existing experimental results and are analyzed with the stress distribution of the shotcrete and steel support obtained numerically. As a result, it is shown that the proposed approach can predict the load capacities of each material and the overall nonlinear behavior of shotcrete lining with steel supports. The change of location of the neutral axis and the flexural resistance ratio of each material are also derived from the stress distribution of the cross section of the shotcrete lining with steel supports. From the results, it is concluded that the flexural resistance performance of steel support should be considered in shotcrete lining design.

A Study on the Composite Behavior of Simply Supported Composite Girders Considering the Partial Interaction (불완전 합성율을 고려한 단순합성형의 합성거동에 관한 연구)

  • Yong, Hwan Sun;Kim, Seok Tae;Park, Jae Yil
    • Journal of Korean Society of Steel Construction
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    • v.9 no.4 s.33
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    • pp.543-555
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    • 1997
  • Generally, in a steel-concrete composite gilder, the shear connector which was constructed between concrete deck and steel girder should have enough stiffness to behave as one body, because the conformity between plate and concrete deck is influences by the stiffness and spacing of the shear connectors. If the stiffness of shear connectors are insufficient, slip would happen at the contact surface. Partial interaction is the case that takes account of slips. In this paper, an easy method is presented to evaluate the stiffness or spacing of the shear connector according to the degree of imperfection without difficult calculations for a composite gilder with partial interaction. Also, the horizontal shearing force applied to the shear connector and the longitudinal axial force, which is occurs at contact surface between concrete deck and steel girder, have been presented in a simple influence line that is various to the parameters of sectional properties, degree of imperfection and applied load points. Furthermore, through the case study, it determined the relationships between the degree of imperfection and the follows 1) spring constants 2) axial force and horizontal shearing force 3) stress and neutral axis by using the partial differential equation based on Newmark's Partial Interaction Theory.

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Flexural Behavior and Design of Concrete-filled U-shape Hybrid Composite Beams Fabricated from 570MPa High-strength Steel (570MPa급 고강도강을 적용한 콘크리트 채움 U형 하이브리드 합성보의 휨거동 및 설계)

  • Lee, Cheol Ho;So, Hyun Joon;Park, Chang Hee;Lee, Chang Nam;Lee, Seung Hwan;Oh, Ha Nool
    • Journal of Korean Society of Steel Construction
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    • v.28 no.2
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    • pp.109-120
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    • 2016
  • Flexural tests of full-scale concrete-filled U-shape hybrid composite beams were conducted. Ordinary (SS400) and high-strength (SM570) steel plates were used in the web and in the bottom flange of U-shape steel section respectively. The primary objectives were to develop the hybrid section configuration with maximized flexural capacity and to investigate its flexural strength and deformation capacity. All the hybrid test specimens in this study exhibited the plastic moment capacity and resonable deformability. It is shown that the plastic stress distribution can be assumed in calculating the flexural strength of the proposed hybrid composite beams if the plastic neural axis is located within 15% of the total beam depth from the top of the composite slab. The procedure for computing the effective flexural stiffness of hybrid composite beams is also recommended based on test results.

Measurement of an Isoelectric Point and Softness of a Zwitterionic Surfactant (양쪽성 계면활성제의 등전점 및 유연력 측정에 관한 연구)

  • Lim, Jongchoo;Kim, Jisung;Mo, Dahee;Lee, Jinsun
    • Applied Chemistry for Engineering
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    • v.23 no.1
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    • pp.112-118
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    • 2012
  • In this study, physical properties of synthesized DE7-OSA82-AO and DEP52-OSA82-AOQ82 zwitterionic surfactants were measured such as critical micelle concentration, surface tension, interfacial tension, contact angle and viscosity. Phase behavior study was also performed. The dual function characteristics of a zwitterionic surfactant were investigated by determining an isoelectric point, which was attained using zeta potential measurements and QCM (quartz crystal microbalance) experiments. The isoelectric point of DE7-OSA82-AO surfactant determined by the zeta potential measurement and QCM experiment was about 7.2 and 7.4, respectively. On the other hand, the isoelectric point of DEP52-OSA82-AOQ82 surfactant determined by the zeta potential measurement and QCM experiment was about 10.9 and 11.0, respectively. The frictional property measured using an automated mildness tester showed that DE7-OSA82-AO surfactant can provide a good softening effect at an acidic or neutral condition. On the other hand, DEP52-OSA82-AOQ82 was found to provide a good softening effect to a fabric surface at a pH below its isoelectric point of 11.

The Evaluation Structure of Auditory Images on the Streetscapes - The Semantic Issues of Soundscape based on the Students' Fieldwork - (거리경관에 대한 청각적 이미지의 평가구조 - 대학생들의 음풍경 체험을 통한 의미론적 고찰 -)

  • Han Myung-Ho
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.8
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    • pp.481-491
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    • 2005
  • The purpose of this study is to interpret the evaluation structure of auditory images about streetscapes in urban area on the basis of the semantic view of soundscapes. Using the caption evaluation method. which is a new method, from 2001 to 2005, a total of 45 college students participated in a fieldwork to find out the images of sounds while walking on the main streets of Namwon city. It was able get various data which include elements, features, impressions, and preferences about auditory scene. In Namwon city, the elements of the formation of auditory images are classified into natural sound and artificial sound which include machinery sounds, community sounds. and signal sounds. Also, the features of the auditory scene are classified by kind of sound, behavior, condition, character, relationship of circumference and image. Finally, the impression of auditory scene is classified into three categories, which are the emotions of humans, atmosphere of the streets, and the characteristics of the sound itself. From the relationship between auditory scene and estimation, the elements, features and impressions of auditory scene consist of the items which are positive, neutral, and negative images. Also, it was able to grasp the characteristics of auditory image of place or space through the evaluation model of streetscapes in Namwon city.

A study on the health awareness and attitude of obese high school students (비만 고등학생의 보건행태조사연구)

  • 박선희;남철현;김상수
    • Korean Journal of Health Education and Promotion
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    • v.15 no.1
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    • pp.115-131
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    • 1998
  • Understanding average abnormal obese high school students' health awareness and attitude, We analyzed problems affect on this to provide basic data for the school health education in the near future. From March, 1997, covering a month period, We investigated 300 average obese students from each 3 school, both boys and girls, around Taegu area. Followings are the summary. 1) Grouping obesity, 86.6% of boys were abdominal type and 54.0% of girls were lump types. 2) IN physical check-up and serum lipid lab., there were a lot of abnormal students for blood pressure, serum glucose, total cholesterol, high density lipoprotein(HDL), low density lipoprotein(LDL), neutral lipid, the rate of lipid in the body, atherosclerosis index and electrocardiogram (ECG).; Especially, for the rate of Lipid in the body, 100.0% were in the abnormal range. 3) The main reasons of stress were on the physique and grade. Over 50.0% of students get rid of their stress by singing and dancing. 4) 46.7% of boys and 56.0% of girls were satisfied with their desks and 51.3% of boys and 48.0% of girls were satisfied with their chairs.; 70.0% of boys and 78.7% of girls usually felt uncomfortable for their desks and chairs. 5) 100.0% of boys and 98.0% of girls have been educated for obesity.; 53.3% of boys and 50.7% of girls were not interested in whether joining in or not, if ‘Obese school’ is open. 60.7% of boys get information about weight loss from television, while 41.3% of girls get it from all sorts of publications.; Both sexes said eating convenience food is the main reason to be obese. Most frequent disease is high blood pressure.; 30.0% of boys and 31.3% of girls were hypertensives. 6) 84.7% of boys and 78.0% of girls are awake to the seriousness of obesity from their families. 58.7% of boys and 66.0% of girls sometimes have meals with their families. For the boys, 30.0% of them eat fruit and 29.3% eat cookies while 37.3% of girls eat cookies for their snacks. Both 57.3% of boys and 40.0% of girls have a snack once a day and they drink soft drinks frequently. Both 32.0% of boys and 46.7% of girls have midnight meals 1-2times a week. 7) Both 45.3% of boys and 50.0% of girls suddenly gained their weight in the elementary school times. 30.0% of boys exercise 1 hour for a week, while 48.0% of girls don't exercise. For the exercise hour, both 53.3% of boys and 42.0% of girls exercise for 10-30 minutes a time. 59.7% of boys and 82.0% of girls strongly don't trust in the informations on weight loss. Both 74.0% of boys and 75.3% of girls think physical therapy is the most suitable way for obesity care.

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