• 한국건설순환자원학회논문집
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• 제9권3호
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• pp.236-245
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• 2021

노출 환경 및 설계 변수의 변화에 따라 내구수명은 큰 범위를 가지고 변화하게 되므로 설계자 입장에서는 내구수명의 변동성을 이해하는 것은 중요하다. 최근 들어 탄소 중립을 위하여 플라스틱 혼소재가 클링커 생산 시 원료로 사용되고 있는데, 이러한 경우, 시멘트의 염화물 함유량은 증가하게 된다. 본 연구의 목적은 플라스틱 혼소재를 사용하여 초기 염화물량이 증가할 경우, 다양한 노출 환경과 설계 변수를 고려하여 내구수명이 어떤 수준으로 변화하는지에 대한 연구이다. 이를 위해 4 수준의 초기 염화물량을 설정하였으며, 3 수준의 표면 염화물량을 포함한 다양한 환경 조건에 따라 내구수명을 LIFE 365 프로그램을 이용하여 평가하였다. 해석 변수로서 임계 염화물량, 고로슬래그 미분말 치환 혼입율, 물-결합재 비, 피복두께, 단위 결합재량, 초기 염화물량을 설정하였다. 초기 염화물량이 증가함에 따라 내구수명은 감소하는 경향을 보이지만 이 값을 1,000ppm까지 허용해도 내구수명의 큰 감소는 나타나지 않았다. 또한 슬래그 치환율을 증가시킬 경우 더 높은 내구수명을 확보할 수 있는데, 이는 고로슬래그 미분말이 외부 염화물 이온의 확산 저감과 동시에 자유 염화물을 고정시키는 효과가 있기 때문이다. 초기 염화물량의 허용 농도를 유럽기준과 같이 증가시키는 것도 지속가능성 향상과 탄소량을 저감시키는 데 도움이 될 것으로 판단된다. 또한 표면 염화물량이 낮고 혼화재(슬래그)를 사용한 경우, 초기 염화물량의 영향은 상대적으로 낮았지만 표면염화물량이 높은 경우, 노출환경을 고려한 신중한 배합설계가 필요하다.

• 식품과학과 산업
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• 제49권2호
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• pp.18-24
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• 2016

Sodium chloride (NaCl) is a very important as one of major food ingredients in food industries. Recently, as the potential risk of adult diseases such as hypertension by overingestion of sodium, health authorities of many countries are executing policies for the reduction of sodium to suppress the overingestion of sodium by intake of NaCl. As general ways, the replacement of NaCl with either alternative salts, such as solar salts and minerals, for examples calcium, magnesium, potassium, lactic acid, and so on, and the addition of flavor enhancers were used to reduce the contents of sodium in foods. Recently, controls of particle size of sodium chloride or release point are emerging as new salt-manufacturing technologies for the sodium reduction. Upon reducing NaCl in foods it is important to develop practically adaptable technologies on the basis of the consideration of the unique functions of NaCl in foods, in particular effects on rheological characters, function as a humectant, shorten shelf life time, and so on.

• 대한수의학회지
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• 제34권1호
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• pp.25-36
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• 1994

The inward tail current after a short depolarizing pulse has been known as Na-Ca exchange current activated by intracellular calcium which forms late plateau of the action potential in rabbit atrial myocytes. Chloride conductance which is also dependent upon calcium concentration has been reported as a possible tail current in many other excitable tissues. Thus, in order to investigate the exsitance of the calcium activated chloride current and its contribution to tail current, whole cell voltage clamp measurement has been made in single atrial cells of the rabbit. The current was recorded during repolarization following a brief 2 ms depolarizing pulse to +40mV from a holding potential of -70mV. When voltage-sensitive transient outward current was blocked by 2 mM 4-aminopyridine or replacement potassium with cesium, the tail current were abolished by ryanodine$(1{\mu}M)$ or diltiazem$(10{\mu}M)$ and turned out to be calcium dependent. The magnitudes of the tail currents were increased when intracellular chloride concentration was increased to 131 mM from 21 mM. The current was decreased by extracellular sodium reduction when intracellular chloride concentration was low(21 mM), but it was little affected by extracellular sodium reduction when intracellual chloride concentration was high(131 mM). The current-voltage relationship of the difference current before and after extracellular sodium reduction, shows an exponential voltage dependence with the largest magnitude of the current occurring at negative potentials, with is similar to current-voltage relationship at negative potentials, which is similar to current-voltage relationship of Na-Ca exchange current. The current was also decreased by $10{\mu}M$ niflumic acid and 1 mM bumetanide, which is well known anion channel blockers. The reversal potentials shifted according to changes in chloride concentration. The current-voltage relationships of the niflumic acid-sensitive currents in high and low concentration of chloride were well fitted to those predicted as chloride current. From the above results, it is concluded that calcium activated chloride component exists in the tail current with Na-Ca exchange current and it shows the reversal of tail current. Therefore it is thought that in the physiologic condition it leads to rapid end of action potential which inhibits calcium influx and it contributes to maintain the low intracellular calcium concentration with Na-Ca exchange mechanism.

• 한국건축시공학회지
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• 제11권4호
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• pp.379-386
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• 2011

Durability of concrete is an important issue, and one of the most critical aspects affecting durability is chloride diffusivity. Factors such as water.cement ratio, degree of hydration, volume of the aggregates and their particle size distribution have a significant effect on chloride diffusivity in concrete. The use of polypropylene fibers(particularly very fine and well dispersed micro fibers) or mineral additives has been shown to cause a reduction in concrete's permeability. The main objective of this study is to evaluate the manner in which the inclusion of fiber(in terms of volume and size) and blast furnace slag(BFS) (in terms of volume replacement of cement) influence the chloride diffusivity in concrete by applying 3D computer modeling for the composite structure and performing a simulation of the chloride penetration. The modeled parameters, i.e. chloride diffusivity in concrete, are compared to the experimental data obtained in a parallel chloride migration test experiment with the same concrete mixtures. A good agreement of the same order is found between multi.scale microstructure model, and through this chloride diffusivity in concrete was predicted with results similar to those experimentally measured.

• 한국동물위생학회지
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• 제18권2호
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• pp.163-176
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• 1995

Triphenyl Tetrazolium Chloride(TCC) reduction test is simple and sensitive to some residual antibiotics (especially to penicillin) in milk, but comparatively insensible to sulfo-namides. The volumn of sample is also large. Thus this study was undertaken to increase the detectable level of sulfonamides in raw milk. In this study, we used small transparent plastic hole and pulp disc instead of 10m1 test tube and made test medium in which was added 0.08%TTC, 0.3% agar, 10% skim milk, approximately $10^6$ CFU/ml streptococcus thermophilus and 5ppm Trimethoprim to enhance the sensitivity for sulfonamides The results of TCC reduction test by disc plate method were summarized as follows : 1. sensitivity to residual sulfonamides were much higher than official TCC reduction test. Detectable limites of sulfamethazine, sulfamerazine, sulfathiazole, sulfachloropy-ridazine, sulfadimethoxine, sulfamononethoxine, sulfadiazine and sulfaquinoxaline were 0.1-0.5ppm levels. 2. Detectable limites to some antibiotics were simillar or good than that of official method as 0.005-0.1ppm to three ${\beta}$ -lactams, 0.25-0.5ppm to one macrolide, 2-10ppm to three aminoglycosides, 0.2-0.5ppm to three tetracycline, 0.1-0.5ppm to chloramphenicol. 3. Only 0.1ml of milk was needed to test and the test medium could be stored appnoximatly 7days in the refrigerator. So test procedure was convenient than offcial method. 4. These results suggest that disc plate method is more useful to detect bacterial growth inhibition substances including sulfonamides in raw milk.

• 대한화학회지
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• 제22권1호
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• pp.37-44
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• 1978

$BH_3$-THF 용액에 염화리튬을 가한 새로운 환원계의 환원특성에 대한 연구가 대표적인 작용기를 가진 유기화합물을 가지고 표준조건($0^{\circ}$, THF)에서 이루어졌다. 조사 연구된 화합물중 벤조페논, 4가지 에스테르 및 시클로헥센은 $BH_3$ 환원과 별 차이를 보이지 않았으나, 2-헵탄온, 아세토페논, 염화벤조일, 프탈산무수물, 그리고 3가지 에폭시화물은 소량의 염화리튬에 의해 빠른 속도로 환원이 완결 되었다. 특히 에폭시화시클로헥센의 환원에 있어서는 소량의 염화리튬 존재하에서는 정량적으로 시클로헥산올을 생성하였으나 염화리튬의 양이 증가하면 2-클로로시클로헥산올이 시클로헥산올과 함께 생성됨을 알았다. 또한, 에폭시화시클로헥센과의 반응에 있어서 질산리튬은 염화리튬과는 달리 별로 효과가 없었다. 따라서 보란-염화리튬용액에 클로로수소화붕소리튬의 생성가능성을 논의하였다.

• Bulletin of the Korean Chemical Society
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• 제7권4호
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• pp.296-298
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• 1986

Carboxylic acid anhydrides are rapidly reduced with borane-lithium chloride (1:0.1) system to give corresponding alcohols (diols in the case of cyclic anhydride) quantitatively in tetrahydrofuran at room temperature. This reagent tolerates aromatic acid ester, nitro, and halide functional groups, however competitively reduces aliphatic ester and nitrile groups.

• Computers and Concrete
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• 제13권1호
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• pp.17-30
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• 2014

This research presents the effect of various ground pozzolanic materials in blended cement concrete on the strength and chloride penetration resistance. An experimental investigation dealing with concrete incorporating ground fly ash (GFA), ground bottom ash (GBA) and ground rice husk ash (GRHA). The concretes were mixed by replacing each pozzolan to Ordinary Portland cement at levels of 0%, 10%, 20% and 40% by weight of binder. Three different water to cement ratios (0.35, 0.48 and 0.62) were used and type F superplasticizer was added to keep the required slump. Compressive strength and chloride permeability were determined at the ages of 28, 60, and 90 days. Furthermore, using this experimental database, linear and nonlinear multiple regression techniques were developed to construct a mathematical model of chloride permeability in concretes. Experimental results indicated that the incorporation of GFA, GBA and GRHA as a partial cement replacement significantly improved compressive strength and chloride penetration resistance. The chloride penetration of blended concrete continuously decreases with an increase in pozzolan content up to 40% of cement replacement and yields the highest reduction in the chloride permeability. Compressive strength of concretes incorporating with these pozzolans was obviously higher than those of the control concretes at all ages. In addition, the nonlinear technique gives a higher degree of accuracy than the linear regression based on statistical parameters and provides fairly reasonable absolute fraction of variance ($R^2$) of 0.974 and 0.960 for the charge passed and chloride penetration depth, respectively.

• Computers and Concrete
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• 제11권4호
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• pp.305-316
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• 2013

This paper aims to study the effect of measurement methods and cracking on chloride transport of concrete materials. Three kinds of measurement methods were carried out, including immersion test, rapid migration test and steady-state migration test. All of these measurements of chloride transport show that chloride ion diffusion coefficient decreased with the reduction of water to cement ratio. Results of the immersion test were less than that of rapid migration test and steady-state migration test. For the specimen of lower water to cement ratio, the external electrical field has little effect on chloride binding relatively. Compared with the results obtained by these different measurement methods, the lower water to cement ratio may cause smaller differences among these different methods. The external voltage can reduce chloride binding of concrete, and the higher electrical field made a strong impact on the chloride binding. Considering the effect of high voltage on the specimen, results indicate that results based on the steady-state migration test should be more reasonable. For cracked concrete, cracking can accelerate the chloride ion diffusion.

• 자원리싸이클링
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• 제9권4호
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• pp.3-15
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• 2000

전기로 더스트 중에 함유된 Zn, Pb, Cl, Fe, Cu 및 Cd의 건식 환원반응기구를 규몽하고자 탄소뿔 첨가한 더스트 Briquette를 제조하여 Ar 가스 분위기 하의 $800^{\circ}C$ ~ $1100^{\circ}C$반응온도에서 실험을 행하였다. 탄소에 의한 Zn 화합물으 환원반응은 온도상승에 따라 민감하게 나타났으며 반응초기에는 화학반응에 의한 음속단계로 활성화에너지 값은 약 120.6 kl/mole이었다. 한편, Pb와 Cl은 $PbCl_2$의 형태로 휘발되었으며 이들의 휘발제거율은 거의 일치하였다. 또한, 환원제를 첨가하지 않는 경우가 환원제 첨가시 보다 휘발제거율이 빨라 Pb의 대부분은 염화휘발에 의해 제거됨을 알 수 있었다. Cu는 염화휘발에 의해 최대 약 30% 제거되고 나머지 대부분은 Fe와 함께 더스트 중에 잔존하여 Cd은 $1000^{\circ}C$에서 15분만에 거의 100%의 휘발제거율을 나타내었다.