• 한국가스학회지
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• 제20권1호
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• pp.13-22
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• 2016

본 연구에서는 다단계 수압파쇄와 수평시추가 적용된 셰일가스정에서 생산자료의 유동형태에 따라 적절한 분석 방법과 궁극가채량을 산출하는 기법을 결정하는 방법을 정리한 흐름도를 제안하였다. 또한 1차 천이유동만이 나타나는 현장자료에 대해 생산천이유동 분석을 수행할 때 고려해야 하는 사항들을 제안하였다. log-log 그래프와 시간제곱근 그래프 분석을 통해 생산자료의 유동 특성을 분류할 수 있고, 이 결과, 1차 천이유동만이 나타나는 생산자료는 이 유동이 종료되는 시점을 정확히 예측하여 이 시점을 기준으로 생산성을 각각 예측하여야 한다. 이 시점은 미세탄성파 탐사자료 해석을 통해 균열자극부피의 면적을 계산함으로써 산출할 수 있다. 공저압력자료나 미세탄성파 탐사자료가 없다면 셰일가스정에 적절한 경험적 방법을 활용하여 생산성을 예측할 수 있다. 생산기간이 짧은 자료는 상대적으로 생산기간이 긴 인접 생산정의 자료를 활용하여 생산기간의 적절성을 평가한 후 필요하다면 생산초기 자료를 제외하고 분석하는 것이 정확도를 향상시킬 수 있다. 또한 미세탄성파 탐사자료 해석에 의해 산출된 SRV는 분석방법이나 분석자의 주관에 의해 과대, 과소 평가될 수 있기 때문에 파쇄 단계, 파쇄유체 주입량, 생산성 분석을 통한 적절성평가를 수행하여 필요한 경우, 저류층 시뮬레이션, 균열모델링, 생산천이분석을 통해 재산정하는 것이 필요하다.

• The Korean Journal of Pain
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• 제13권1호
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• pp.126-129
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• 2000

Age-related osteoporotic compression fractures occur frequently in old aged group recently. Percutaneous vertebroplasty has recently been introduced as a therapeutic method for the treatment of pain associated with osteoporotic vertebral compression fracture. Percutaneous intravertebral injection of PMMA (polymethylmethacrylate) results in marked reduction in pain and morbidity. Among complications during vertebroplasty with PMMA, pulmonary embolism is repotred occasionally but the reports about hypotension are not common. This case is a report of a patient whom significant hypotension occured during percutaneous vertebroplasty.

• 한국염색가공학회지
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• 제31권4호
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• pp.354-362
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• 2019

In order to apply thermoplastic composites using PETG resin to various industrial fields such as bicycle frames and industrial parts, it is necessary to verify the impact resistance, durability and mechanical properties of the manufactured composite materials. To improve the mechanical properties, durability and impact resistance of PETG resin, an amorphous resin, in this study, compound and injection molding process were carried out using various additives such as TiO2, carbon black, polyolefin elastomer, and PETG amorphous resin. The thermal and mechanical properties of the thermoplastic composites, and the Charpy impact strength. The analysis was performed to evaluate the characteristics according to the types of additives. DSC and DMA analyzes were performed for thermal properties, and tensile strength, flexural strength, and tensile strength change rate were measured using a universal testing machine to evaluate mechanical properties. Charpy impact strength test was conducted to analyze the impact characteristics, and the fracture section was analyzed after the impact strength test. In the case of POE material-added thermoplastic composites, thermal and mechanical properties tend to decrease, but workability and impact resistance tend to be superior to those of PETG materials.

• 한국정밀공학회지
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• 제21권10호
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• pp.34-41
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• 2004

A new method to fabricate the fine magnetic abrasives by using mechanical alloying is proposed. The mechanical alloying process is a solid powder process where the powder particles are subjected to high energetic impact by the balls in a vial. As the powder particles in the vial are continuously impacted by the balls, cold welding between particles and fracturing of the particles take place repeatedly during the ball milling process using a planetary mill. After the manufacturing process, fine magnetic abrasives which the guest abrasive particles c lung to the base metal matrix without bonding material can be obtained. The shape of the newly fabricated fine magnetic abrasives was investigated using SEM and its polishing performance was verified by experiment. It is very helpful to finishing the injection mold steel in final polishing stage. The areal ms surface roughness of the workpiece after several polishing processes has decreased to a few nanometer scales.

• 농업과학연구
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• 제17권2호
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• pp.142-145
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• 1990

충남대학교 부속동물병원에 내원(來院)한 우측후지(右側後肢)의 부전골에 골절상(骨折傷)을 받은 6개월금(個月今)의 꽃사슴에 대하여 대퇴골절단술(大腿骨切斷術)을 실시한 증례(症例)를 보고한다. 마취는 체중 kg당 1.2mg의 xylazine을 근육주사하여 실시하였으며, 수술방법은 개에서의 대퇴골절단술(大腿骨切斷術)과 같은 방법(方法)을 시도하였다. 수술직후 일어서기, 걷기, 달리기등의 운동에 불편을 보였지만 시간이 경과함에 따라 숙달되는 것을 관찰할 수 있었으며, 절단수술후(切斷手術後) 현재(現在)까지 (약(約) 6개월(個月)) 병적(病的) 미후(微候)는 인정되지 않았다.

• Journal of Korean Neurosurgical Society
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• 제63권4호
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• pp.532-538
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• 2020

Traumatic arteriovenous fistulas (AVFs) involving the external carotid artery are exceedingly rare in young adults. Since an AVF is the most common life-threatening cause for pulsatile tinnitus (PT), meticulous evaluation and treatment of patients with PT is crucial. Here, we present two traumatic AVF cases treated with coil embolization leading to no residual fistulous connections followed by an immediate and complete resolution of PT. A 20-year-old man developed left ear tinnitus three months after a traumatic brain injury involving the right temporal bone fracture. Cerebral angiography demonstrated an enlarged left middle meningeal artery (MMA) and a fistular point at the posterior branch of the MMA draining to the middle meningeal vein (MMV) and the left pterygoid plexus, suggesting an AVF. Another 18-year-old girl developed left tinnitus, left exophthalmos, and conjunctival injection 6 months after a traffic accident involving no demonstrable abnormal findings in the radiologic exam. Magnetic resonance angiography demonstrated a markedly dilated left MMA draining to the MMV, left cavernous sinus, and left superior ophthalmic vein. In both cases, coil embolization was performed with total obliteration of the fistular point.

• Advanced Composite Materials
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• 제18권3호
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• pp.221-232
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• 2009

The allylamine plasma treatment is used to modify the surface properties of vapor grown carbon fibers (VGCF). It is to improve the interfacial bonding between the VGCF and epoxy matrix. The allylamine plasma process was performed by batch process in a vacuum chamber, using gas injection followed by plasma discharge for the durations of 20, 40 and 60 min. The interdependence of mechanical properties on the VGCF contents, treatment time and interfacial bonding between VGCF/ep was investigated. The interfacial bonding between VGCF and epoxy matrix was observed by scanning electron microscopy (SEM) micrographs of nanocomposites fracture surfaces. The changes in the mechanical properties of VGCF/ep, such as the tensile modulus and strength were discussed. The mechanical properties of allylamine plasma treated (AAPT) VGCF/ep were compared with those of raw VGCF/ep. The tensile strength and modulus of allyamine plasma treated VGCF40 (40 min treatment)/ep demonstrated a higher value than those of other samples. The mechanical properties were increased with the allyamine plasma treatment due to the improved adhesion at VGCF/ep interface. The modification of the carbon nanofibers surface was observed by transmission electron microscopy (TEM). SEM micrographs showed an excellent dispersion of VGCF in epoxy matrix by ultrasonic method.

• Journal of Chest Surgery
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• 제53권4호
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• pp.233-241
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• 2020

Vagal damage and subsequent pyloric denervation inevitably occur during esophagectomy, potentially leading to delayed gastric emptying (DGE). The choice of an optimal pyloric procedure to overcome DGE is important, as such procedures can lead to prolonged surgery, shortening of the conduit, disruption of the blood supply, and gastric dumping/bile reflux. This study investigated various pyloric methods and analyzed comparative studies in order to determine the optimal pyloric procedure. Surgical procedures for the pylorus include pyloromyotomy, pyloroplasty, or digital fracture. Botulinum toxin injection, endoscopic balloon dilatation, and erythromycin are non-surgical procedures. The scope, technique, and effects of these procedures are changing due to advances in minimally invasive surgery and postoperative interventions. Some comparative studies have shown that pyloric procedures are helpful for DGE, while others have argued that it is difficult to reach an objective conclusion because of the variety of definitions of DGE and evaluation methods. In conclusion, recent advances in interventional technology and minimally invasive surgery have led to questions regarding the practice of pyloric procedures. However, many clinicians still perform them and they are at least somewhat effective. To provide guidance on the optimal pyloric procedure, DGE should first be defined clearly, and a large-scale study with an objective evaluation method will then be required.

• Geomechanics and Engineering
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• 제25권4호
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• pp.295-302
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• 2021

Cross-borehole electrical resistivity tomography (ERT) is an effective groundwater detection tool in geophysical investigations. In this paper, an artificial water injection test was conducted on a small clay sample, where the high-resolution cross-borehole ERT was used to investigate the moisture migration law over time. The moisture migration path can be two-dimensionally imaged based on the relationship between resistivity and saturation. The hydraulic conductivity was estimated, and the magnitude ranged from 10^-11 m/s to 10^-9 m/s according to the comparison between the simulation flow and the saturation distribution inferred from ERT. The results indicate that cross-borehole ERT could help determine the resistivity distribution of small size clay samples. Finally, the cross-borehole ERT technique has been applied to investigate the self-sealing characteristics of clay.

• 대한골관절종양학회지
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• 제8권1호
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• pp.20-26
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• 2002

섬유성 골이형성증은 골의 발육 이상으로 해면골이 섬유성 조직으로 대치되어 나타나는 양성 병변으로 대퇴골, 경골, 두개골, 늑골, 상완골 등에 호발하며 동통, 진행하는 병변, 병적 골절 등을 일으키기 쉬워 여러 가지 치료법이 시도되어 왔으나 그 중 골 소파 및 골 이식술이 현재까지 널리 시행되고 있다. 본 교실에서는 17세 여자 환자로 우측 상완골 전장에 걸친 다발성 골 낭종을 동반한 섬유성 골이형성증 환자에 steroid 주입법을 약 3개월 간격으로 총 2차례 시행하였고 처음 주입 후 약 11개월 후에 시행한 추시 단순 방사선 촬영상 병변의 크기가 감소하였고, 골음영 및 피질골의 두께가 증가하였으며, 자기공명영상촬영 검사상 병변의 크기가 상당히 감소하였고, T2 강조 영상에서 정상 골수의 신호강도와 비슷하게 변화 하였으며, 처음 주입 후 약 2년 8개월 후의 외래 추시상 통증 호소하지 않고 무리하지 않는 한도내에서 큰 불편 없이 지내고 있어 섬유성 골이형성증의 호전 소견을 보였기에 문헌고찰과 함께 보고하는 바이다.