Earticle

연구목적: 본 연구에서는 기존 주입공법의 문제점을 개선하기 위한 친환경적인 주입재를 개발하고 시 험을 통해 현장 적용성을 확인하기 위한 연구를 수행하였다. 연구방법: 친환경 주입재와 기존 주입재 (L.W, S.G.R)의 호모겔 공시체를 각각 제작하고, 실내시험(일축압축강도, 투수계수, 수축성, 내화학성, 용출성, 어독성, 폐기물공정)을 실시하여 물리화학적 및 공학적 특성을 비교·검토하였다. 연구결과: 실 내시험 결과 친환경 주입재가 기존 주입재에 비해 모든면에서 우수하였으며 주입재료로서 실제 현장 에서 시공적합성을 실험하고 지반개량 효과를 확인할 수 있었다. 결론: 본 연구에서 사용된 주입재는 강 도증가 및 투수성 감소 등의 기본적인 물성을 만족하면서 친환경적인 특성을 가지고 있어 지반의 조건 과 적용에 관계없이 범용적으로 사용이 가능한 재료로 판단되었다.

Purpose: In this study, a grout material mixed using non-alkaline silica-based materials, which is an eco-friendly injection material to stabilize ground, is investigated to improve conventional problems. Method: The homogel specimens of Eco-Friendly Non-Alkaline Silica Sol (ENASS) and L.W. and S.G.R., representative silicate grouting are manufactured. Physicochemical and engineering properties of the specimens are evaluated in laboratory with uniaxial compression strength, hydraulic conductivity, shrinkage, chemical resistance, elution, fish poison, waste leaching. Result: Laboratory test results show that the ENASS was superior in all aspects compared to the existing injection matirial. The suitability of the grout material with ENASS is investigated with filed tests. Conclusion: The results of laboratory and field tests demonstrates that the grout material with ENASS is eco-friendly material that increases the strength, decreases the permeability, and discharges pollutants without leaching.

Reservoirs, which make up most of South Korea's reservoirs, are located in rural areas. In the case of rural reservoirs, about 75% have been reported over 50 years old aged reservoirs constructed before the 1960s. Reservoirs are important facilities that store and supply water necessary for daily life. However, if it is destroyed, the reservoir can cause a lot of damage, so continuous management is necessary. As a method for strengthening old reservoirs, a method using cement has been widely applied. However, OPC is a product that uses a lot of carbon dioxide and natural resources. Therefore, the amount of cement should be reduced. Against this background, in this study, the ground injection material of utilizing circulation resources was applied to the site. Applied reservoirs have been around for 75 years and leaks have occurred in some sections. The application method was constructed in two rows, up to a depth of 12m. After reinforcement, the electrical resistivity test was conducted three times. As a result, similar resistance was shown at 1 month after construction. And after 6 months, the saturation area decreased. And the performance after reinforcing the aged reservoir was examined. As a result of the review, this study confirmed that the applicability was equivalent to that of OPC, and the excellent performance of reinforcing the aged reservoir was shown.

굴 양식의 부산물인 패각과 혼합 폐플라스틱을 이용하여서 패각의 함유 및 패각 표면 개질에 따른 물성과의 상관관계에 관한 연구를 하였다. 먼저 패각과 순수 LDPE를 twin screw extruder를 사용하여 40 wt%의 마스터배치(masterbatch, M/B)를 제조한 후, 다시 이를 순수 LDPE와 섞어서 패각 함유 10 wt%에서 40 wt%까지의 사출용 시편을 제조하였다. 한편 순수 LDPE 대신에 혼합 폐플라스틱을 이용하여 상기와 동일한 방법으로 사출용 시편을 제조하였고, 패각과 혼합 폐플라스틱과의 상용성을 향상시키기 위해서 패각의 표면을 양이온과 양이온성 계면활성제로 치환하였다. 표면 개질 패각을 이용하여 혼합 폐플라스틱과의 혼입을 통해 상기와 동일 함량을 갖는 사출 시편을 제조한 후 기계적 물성을 측정하였다. 측정 결과 표면을 개질한 패각을 함유한 혼합 폐플라스틱은 미개질 패각 함유 시편에 비해 매트릭스와의 상용성 증가로 인해 굴곡강도, 압축강도, 열변형 온도 등의 물성 향상을 나타내었다. 따라서 패각을 함유시 혼합 폐플라스틱의 기계적 물성의 향상으로 인해 새로운 용도 개발이 가능한 것을 확인하였다.

Mechanical properties of shell powder containing mixed recycled plastics were investigated depending on the shell content and surface modification. First, shell powder and LDPE were compounded using the twin screw extruder to manufacture 40 wt% master batch(M/B), and the M/B was blended with LDPE to produce bulk specimens with 10, 20, 30 and 40 wt% shell content. To improve the compatibility of shell powder with mixed recycled plastics matrix, surface of shell powder was chemically modified with cations or cationic surfactant. Surface modified shell was also used to prepare bulk specimens with the same shell content. Mechanical property analysis showed obvious improvement for the surface modified shell containing bulk specimens compared to unmodified ones. These results can lead to the development of new applications for the mixed recycled plastics.

This study is to investigate the effect of material for GPF on the PM reduction characteristics before the improvement of filter efficiency in GPF. The material of GPF was changed to ceramic and metal. The ceramic material was applied to SiC, and the metal materials were employed to STS 310s, STS 316s, and STS 410s. The number of honeycomb and wall thickness were set to 200CPSI, 0.3987mm, respectively. The inlet mass flow was fixed at 0.00695kg/s. The inlet air temperature was changed from 500K(0s∼350s) to 1000K(400s∼900s). It was found that the differences in loading amount according to the GPF materials were difficult to observe because the pore density and porosity were set to be the same to affect only the mechanical properties. STS 310s with the highest temperature value had the fastest regeneration time. However, as time goes on, SiC had the highest regeneration rate characteristics. The reason is that the high-temperature region in the GPF by the high-temperature exhaust gas was rapidly transferred toward the outlet due to the high thermal conductivity of SiC.

본 연구는 순환자원 활용 저시멘트 주입재에 대하여, SGR공법에 적용하는 OPC 및 SC를 대체하는 주입재로 검토를 위해 실내에서 겔타임 시험과 양생일별 호모겔 강도시험을 실시하여 비교하였다. 겔타임시험의 경우 표준시방 서에서 제시하는 완결 및 급결 조건을 OPC 및 SC는 만족하는 결과를 나타내었지만. 순환자원 활용 저시멘트 주입재 의 경우 급결 조건의 겔타임은 만족하지 못하였다. 수정배합비를 이용하여 급결조건으로 순환자원 활용 저시멘트 주 입재의 겔타임시험을 실시한 결과 평균 8.8sec로 확인되어 급결조건을 만족하는 것으로 확인되었다. 또한 겔타임 조 건을 만족하는 배합비로 호모겔 강도를 측정한 결과 양생일 28일 기준 1.12-1.88MPa의 압축강도로 나타났다.

In this study, a gel time test in laboratory test and a homogel compressive strength test for each curing day were conducted to compare low cement injection materials utilizing recycled resources as replacement materials for OPC and SC used in the SGR method. In the case of the gel time test, OPC and SC showed results that satisfied the quick setting and final setting conditions presented in the standard mixing ratio. In the case of low cement injection material utilizing recycled resources, the gel time under quick setting conditions was not satisfied. As a result of conducting a gel time test of low cement injection material using recycled resources under quick setting conditions using a modified mixing ratio, the average time was found to be 8.8 sec, confirming that it satisfies the quick setting conditions. In addition, as a result of measuring the homogel compressive strength with a mixing ratio that satisfies the gel time conditions, the compressive strength was found to be 1.12-1.88 MPa as of the 28th day.

본 연구에서는 케미칼 그라우팅웅의 폴리우레탄계 2성분 주입약액 및 그의 반응고결물인 발포 고결체의 물리적, 화학적 성질에 관하여 조사하였다. 이들의 성질을 좌우하는 요소들을 규명키 위한 실험결과, 폴리우레탄계 주입약액 및 그의 고결생성물의 물리적, 화학적 거동은 토질의 상태 즉, 온도, 함수비 및 흙의 밀도 등과 같은 주입대상지발의 조건에 의해 크게 영향받는 것을 알 수 있었다. 또한, 폴리우레탄계 약액그라우팅의 지반보강효과 및 차수효과를 검증키 위해 현재 건설중인 지하철등에서의 터널 굴착시의 폴리우레탄계 약액주입 시공예를 중심으로 그 효과를 조사하였다.

The physical and chemical properties of polyurethane-yieding twofomponent liquid injection mixture and those of the resulting polyurethane solid foam for chemical grouting are investigated. The chemical experiments on the factors influencing the properties of polyurethane show that the behaviors of polyurethane-yielding liquid material and those of the produced polyurethane solid foam are greatly affected by the ground conditions such as temperature, water content and density of soil. The ground reinforcing and water -blocking effects of polyurethane grouting are examined through field case history of tunnel ericavati on of the subway under construction.

Fluorene derivatives are well-known in the polymer OLEDs due to their good charge carrying property. In this work, we synthesized a series of conjugated copolymers based fluorene derivative and phenylamine units by using Buchwald-Hartwig reaction in order to investigate their photoreactivities and use as the HIL/HTL layers of OLEDs using solution processes.

The aim of this study was to establish an injection protocol of a test bolus and a main bolus of contrast material for computed tomographic pulmonary angiography (CTPA) for visualizing optimal pulmonary arteries in normal beagle dogs. CTPA using a test bolus method from either protocol A or B were performed in each of four normal beagle dogs. In protocol A, CTPA was conducted with a scan duration for around 8 s, setting the contrast enhancement peak of the pulmonary trunk in the middle of the scan duration. The arrival time to the contrast enhancement peak was predicted from a previous dynamic scan using a test bolus (150 mg iodine/kg) injected with the same injection duration using for a main bolus (450 mg iodine/kg). In protocol B, CTPA was started at the predicted appearance time of contrast material in the pulmonary trunk based on a previous dynamic scan using a test bolus injected with the same injection rate as a main bolus. CTPA using protocol A showed the optimal opacification of the pulmonary artery with pulmonary venous contamination. Proper CTPA images in the absence of venous contamination were obtained in protocol B. CTPA with a scan duration for 8 s should be started at the appearance time of contrast enhancement in the pulmonary trunk, which can be identified exactly when a test bolus is injected at the same injection rate used for the main bolus.

Objectives. Injection laryngoplasty (IL) is one of the major options for treatment of unilateral vocal fold paralysis (UVFP). Early IL in patients with abrupt-onset UVFP can reduce hoarseness and aspiration-related discomfort and complications. Temporary or short-lasting materials are recommended for the early IL since permanent or long-lasting materials may negatively affect the voice quality when vocal fold motion is spontaneously recovered. Methods. Patients who received IL with a long-lasting material (ArteSense) within 1 month following development of postoperative UVFP were enrolled for this study. They were categorized into a spontaneously recovered group (n=30) and unrecovered group (n=276) from UVFP. The subjective and objective voice parameters were collected before and 6 months after IL. Patients’ demographics and collected voice parameters were compared between the two groups. Results. Age and sex distributions were not different between the two groups. Aspiration symptom, maximum phonation time (MPT), jitter, shimmer, noise to harmonic ratio (NHR), overall grade (G) and breathiness (B) of GRBAS (grade of dysphonia, roughness, breathiness, asthenia, strain) scale score, and voice handicap index (VHI) were significantly improved after IL in both groups. The amounts of improvement in MPT, jitter, shimmer, NHR and VHI were significantly greater in the recovered group. There was no IL-related complication including granuloma formation, hypersensitivity to injection material, or worsening of hoarseness. Conclusion. Early IL with a long-lasting material can be safely performed to improve voice quality and to reduce aspiration episode for the patients with postoperative UVFP, regardless of recovery from the paralysis. The amounts of improvement in the subjective and objective voice parameters were significantly greater in patients who showed spontaneous recovery from UVFP when compared with those in patients who did not.

Purpose: To report the experiences at our institute of pars plana vitrectomy (PPV) in combination with intravitreal triamcinolone acetonide (IVTA) injection in patients with retained lens material after cataract surgery. Methods: The medical records of patients who underwent PPV between January 2005 and December 2006 after complicated cataract surgery in which lens material was dropped into the vitreous cavity were reviewed retrospectively. Results: Five eyes of five patients were treated by vitrectomy and removal of the dislocated lens material and were administered an adjuvant intravitreal injection of 4 ㎎ triamcinolone acetonide at the end of surgery. IVTA administration induced a rapid improvement in vision within six weeks postoperatively. Final visual acuity was 20/32 or better in all patients. Inflammatory cystoid macular edema (CME) that existed preoperatively was promptly improved after IVTA. Intraocular pressure increased transiently in one patient. No procedure-related complications were observed. Conclusions: PPV with additional IVTA was successfully performed in five eyes with retained lens material and resulted in a marked resolution of vitreous inflammation, an improvement in CME and rapid visual recovery. The authors recommend that IVTA administration should be investigated more thoroughly as an adjunct during the management of retained lens material.

In this study, acrylate salt material of new chemical composition for injection grouting was prepared in the state of aqueous solution, and the chemical and physical properties of the material were investigated. The gelation time of the material was freely controllable through the control of added catalysts amount. As the viscosity of the material was very low (2∼3cps), its injection efficiency was expected to be very excellent. The variation of its viscosity plotted with the process of gelation revealed that the efficiency of its penetration into the ground soil was very excellent. The LD$\sub$50/ test on white mouse verified the toxicity of the material was very slight and substantially negligible. The grouting effect using the material was examined through field case histories.

본 연구에서는 바이오주입재를 시멘트와 같은 분말 형태로 주입재를 개발하였다. 바이오그라우팅의 배합비를 선정하기 위해 규산소다 3호 : 물의 비율(50 : 50, 35 : 65, 20 : 80), 시멘트 : 바이오주입재의 비율(100 : 0, 90 : 10, 70 : 30)로 각각 샌드겔 공시체를 제작하여 시간 경과에 따른 geltime을 분석하였다. 그리고 geltime에 따른 일축압축강도를 평가하여 시공조건에 맞는 배합비를 선정할 수 있도록 제시하였다. 실내실험 결과, 규산소다 3호 : 물의 비율이 35 : 65, 시멘트 : 바이오주입재의 비율이 90 : 10일 때 겔타임과 일축압축강도가 잘 나타나 적정한 최적배합비로 확인하였다.

This study aims to develop a bio-grouting material in a powder form like cement. Sand gel samples were produced with the ratio of sodium silicate No.3 to water (50 : 50, 35 : 65, 20 : 80), and the ratio of cement to bio-grouting material (100 : 0, 90 : 10, 70 : 30) to select a mixing ratio of bio-grouting, respectively, and then analyzed the geltime over time. The uniaxial compressive strength was evaluated to select and suggest a mixing ratio optimized for construction conditions. The indoor test reveals that preferred geltime and uniaxial compressive strength is obtained in 35 : 65 with respect to the ratio of sodium silicate No.3 to water, and 90 : 10 with respect to the ratio of cement to bio-grouting material to demonstrate best optimal mixing ratios.

Background and Objectives : Temporary vocal fold injection is not only performed to restore the laryngeal function in temporary unilateral vocal fold paralysis or paresis, but also performed as a test injection prior to the permanent injection. Gelfoam has been safely used for the past several decades for the temporary vocal fold augmentation. Recently, we found a new material, called Radieses Lite, may be used as a temporary injection material. Material and Methods : We report preliminary results of 11 patients who had Radiesse Lite injection with a variety of pathologies. Results : Based on the results from the 6 patients who completed follow-up, the duration of effectiveness of Radiesse Lite seems to be from 2 to 3 months depending on the injection amount. Radiesse Lite satisfies several requirements of the ideal temporary vocal fold injection material in terms of injectability, convenience, duration of effectiveness and safety. Conclusion : The authors concluded that Radiesse Lite might be a good option for temporary vocal fold injection especially in the office setting.

In multi-material injection molding, since two or more materials with different process conditions are used, it is essential to maximize process efficiency by operating the cooling or heating system to a minimum. In this study, Liquid silicone rubber (LSR) that can be cured at a low temperature suitable for the multi-material injection molding was selected and the cure behavior according to the process conditions was analyzed through differential scanning calorimetry (DSC). Dynamic measurement results of DSC with different heating rate were obtained, and through this, the total heat of reaction when the LSR was completely cured was calculated. Isothermal measurement results of DSC were derived for 60 minutes at each temperature from 80 ℃ to 110 ℃ at 10 ℃ intervals, and the final degree of cure at each temperature was calculated based on the total heat of reaction identified from the Dynamic DSC measurement results. As the result, it was found that when the temperature is lowered, the curing start time and the time required for the curing reaction increase, but at a temperature of 90 ℃ or higher, LSR can secure a degree of cure of 80% or more. However, at 80 ℃., it was found that not only had a relatively low degree of curing of about 60%, but also significantly increased the curing start time. In addition, in the case of 110 ℃, the parameters were derived from experimental result using the Kamal kinetic model.

본 연구에서는 세라믹 기계요소를 생산하기 위한 기초연구로서, 세라믹 사출 성형에 대한 기본적인 가공조건과 여러변수들을 고찰하고 가능한한 최대의 세라믹체적 비를 갖고 세라믹입자와 완벽한 융합을 이룰수 있는 최적의 결합제 구성과 세라믹입자 의 충진비율에 따른 혼합체(mixture)의 유동특성을 규명하여 사출성형의 적부를 판별 함과 동시에 그 훈련된 상태를 고찰하여 이후의 공정에서 불균일에 의한 결함이 발생 하지 않도록 정확한 성형조건을 제시하고자 한다. 또한 사출성형에 가장 적절한 혼 합체를 선정하여 탈지공정 및 소결을 행하고 각 공정에서의 부품의 수축률 및 결함을 관찰하여 그 결함의 원인 및 제거방법에 대하여 논의할 것이다. 본 논문에서 제시한 각 공정 및 고찰은 중요한 모든 변수들의 경향 및 특성을 다루었으며 정밀한 세라믹부 품의 신속한 생산을 위한 기초 연구로서 실제 산업체에 응용될 수 있을 것으로 사료된 다.

The fabrication of ceramic machine components by injection molding(CIM : Ceramic Injection Molding) is critically dependent on the shaping and binder extraction techniques. Injection molding is of keen interest to ceramic industries because CIM is suitable for making an intricate shape and manufacturing cost is lower than other process when production scale is large. The success of the molding process is dependent on the correct formulation of the organic vehicle and the achievement of optimum filler loading. Fine alumina powders and polyethylene binder systems were employed to prepare moldable blend then produce a simple specimen by compression molding. Flow characteristics of the mixture was evaluated by viscosity measurement. Optimum binder system and ceramic volume loading for injection molding were determind. A good debinding technique was utilized to improve the quality of debinded parts and save the debinding time. The simple ceramic part was successfully sintered after debinding and its microstructure examined with SEM revealed good consolidation.