• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.21-25
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• 2001

기계부품의 소형화 , 고속화, 그리고 저공해, 저소음이 요구되는 세계적인 추세에서 정밀가공기술은 기계 및 전자산 업에서 중요한 위치를 차지하게 되었다. 특히, 무심연삭공정(Centerless Grinding)은 높은 생산성과 정확한 치수 형성의 능력이 있어서 원통형상을 가공하는 중요한 생산공정으로 사용되어 왔다. 예컨대 VCR의 소형 축. Computer Disk Drive, 초소형 모터, 연료분사기등은 쎈터레스 연삭공정을 통하여 높은 정밀도를 얻고 있다. 하지만 이 공정의 특수성과 측정의 어려움으로 인하여 이러한 정밀형상의 형성과정은 아직도 잘 밝혀져있지 않다. 무심연연삭 공정에서는 부품이 기계에 고정되어 있지 않고 공작물 받침날 위에 올려져 있으며 조절바퀴와 연삭바퀴 사이에 눌려져 있다. 조절바퀴가 마찰력으로 공작물을 돌려주며 연삭바퀴에서 연삭가공이 일어나게 된다. 조절바퀴와 연삭바퀴사이의 거리는 기계 자체의 탄성변형으로 인하여 항시 변화하게 되며 이 거리의 변화가 공작물의 정밀형상 형성에 결정적인 영향을 미치게 된다. 본 연구에서는 무심연삭공정중 공작물과 받침날, 조절바퀴, 연삭바퀴의 상대운동을 기하학적으로 해석하였다. 특히 간섭조건을 사용하여 실제 공작물의 운동을 해석하여 순간 명목 절삭깊이를 구하였다. 또한 연삭 특성실험식을 이용하여 수직 연삭력을 구하고 연삭기의 탄성변형을 구하여 순간 실제 절삭깊이를 계산하였다. 그로부터 진원도형성에 관한 기본식을 유도하였다. 본 연구에서 유도된 진원도 형성 식을 이용하여 실험과 동일한 조건으로 컴퓨터 시뮬레이션을 수행하였다. 그리고 원형중의 어떤 이상형상, 즉, 홈또는 돌기는 반복되어서 다른 돌기 또는 홈을 형성 하게되며 그 반복주기는 공작물이 조절바퀴와 연삭바퀴위에 떠있는 각도에 따라 결점 됨을 확인하였다.'유창성' 에 그 목표를 두고 있는 점을 감안한다면, 시작단계부터 반드시 정확한 발음을 지녀야 하는 가의 문제도 생각해 볼 필요가 있다. 경우에 따라서는, 정확한 발음은 그 언어에 대한 숙련도가 점차 높아짐에 따라 이와 병행하여 이루어지는 경우도 흔히 경험하는 일이기 때문이다. 결국 초등영어 교육과정에도 명시되어 있듯이 '...영어에 대한 친숙함과 자신감을 심어주고, 영어에 대한 흥미와 관심을 지속적으로 유지시키는 것이 중요하기' 때문에 무엇보다 중요한 측면은 흥미와 관심을 유지시키는 지적인 학습활동보다는 정의적인 학습활동의 전개가 필요하다고 하겠다. 유리된 AA의 세포독설과 관련된 세포내의 역할에 대해 의문이 제기되었다., PCL에 SOD-1도 경미하게 나타났으나, 경련이 나타난 쥐에서는 KA만을 투여한 흰쥐와 구별되지 않았다. 이상의 APT의 항산화 효과는 KA로 인한 뇌세포 변성 개선에 중요한 인자로 작용할 것으로 사료되나, 보다 명확한 APT의 기전을 검색하고 직접 임상에 응응하기 위하여는 보다 다양한 실험 조건이 보완되어야 찰 것으로 생각된다. 항우울약들의 항혈소판작용은 PKC-기질인 41-43 kD와 20 kD의 인산화를 억제함에 기인되는 것으로 사료된다.다. 것으로 사료된다.다.바와 같이 MCl에서 작은 Dv 값을 갖는데, 이것은 CdCl$_{4}$$^{2-}$ 착이온을 형성하거나 ZnCl$_{4}$$^{2-}$ , ZnCl$_{3}$$^{-}$같은 이온과 MgCl$^{+}$, MgCl$_{2}$같은 이온종을 형성하기 때문인것 같다. 한편 어떠한 용리액에서던지 NH$_{4}$

• Journal of Gastric Cancer
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• v.8 no.2
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• pp.79-84
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• 2008

Purpose: With advancements in laparoscopic surgery, there have been efforts to expand the indication for laparoscopic surgery up to advanced gastric cancer. However, scant data are available regarding the feasibility and advantages of laparoscopy-assisted distal gastrectomy (LADG) with standard radical D2 lymph node dissection. Materials and Methods: Twenty-two patients who were preoperatively diagnosed with cT1N0M0 gastric cancer underwent LADG with standard D2 lymphadenectomy between February and August 2007. They were compared with patients who underwent conventional open D2 lymphadenectomy with respect to clinicopathologic features, surgical outcomes, and postoperative course. Results: The mean operative time was significantly longer in the LADG group than in the open group ($160{\pm}25min$ vs. $135{\pm}21min$, P<0.001). However, surgical outcomes, such as surgical margin and number of retrieved lymph nodes ($25.7{\pm}11.1$ vs. $26.9{\pm}9.2$, P=ns) were comparable between the groups. The LADG group exhibited quicker postoperative recovery, and both groups exhibited similar postoperative morbidity and mortality. Conclusion: LADG with D2 lymphadenectomy is feasible and safe, with short-term surgical outcomes comparable to those seen in open D2 lymphadenectomy. Further prospective clinical investigation will be needed to better evaluate the advantages of LADG with D2 lymphadenectomy.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.25-30
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• 2023

As 3D printing technology is used in the medical field, interest in metal materials is increasing. The Department of Radiation Oncology uses a shielding block to shield the patient's normal tissue from unnecessary exposure during electron beam therapy. However, problems such as handling of heavy metal materials such as lead and cadmium, reproducibility according to skill level and uncertainty of arrangement have been reported. In this study, candidate materials that can be used for metal 3D printing are selected, and the physical properties and radiation dose of each material are analyzed to develop a customized shielding block that can be used in electron beam therapy. As candidate materials, aluminum alloy (d = 2.68 g/cm³), titanium alloy (d = 4.42 g/cm³), and cobalt chromium alloy (d = 8.3 g/cm³) were selected. The thickness of the 95% shielding rate point was derived using the Monte Carlo Simulation with the irradiation surface and 6, 9, 12, and 16 energies. As a result of the simulation, among the metal 3D printing materials, cobalt chromium alloy (d = 8.3 g/cm³) was similar to the existing shielding block (d = 9.4 g/cm³) in shielding thickness for each energy. In a follow-on study, it is necessary to evaluate the usefulness in clinical practice using customized shielding blocks made by metal 3D printing and to verify experiments through various radiation treatment plan conditions.

• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.293-301
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• 2019

Soft tissue masses of the extremities and torso are a common problem encountered by orthopaedic surgeons. Although these soft tissue masses are often benign, orthopaedic surgeons need to recognize the key features differentiating benign and malignant masses. An understanding of the epidemiology and clinical presentation of soft tissue masses is needed to develop a practical approach for evaluation and surgical management. Size and depth are the two most important factors on which triage decisions should be based. In a differential diagnosis of a tumor, it is important to know the characteristics of the soft tissue mass through detailed history taking and physical examinations before the diagnostic procedures. A variety of imaging studies, such as simple radiography, ultrasound, magnetic resonance imaging, positron emission tomography, computed tomography, bone scan, and angiography can be used to diagnose tumors. Know the ledge of advantages and disadvantages of each imaging study is essential for confirming the characteristics of the tumor that can be observed in the image. In particular, ultrasonography is convenient because it can be performed easily in an outpatient clinic and its cost is lower than other image studies. On the other hand, the accuracy of the test is affected by the skill of the examiner. A biopsy should be performed to confirm the tumor and be performed after all imaging studies have been done but before the final treatment of soft tissue tumors. When a biopsy is to be performed, careful attention to detail with respect to multidisciplinary coordination beforehand, cautious execution of the procedure to minimize complications, and expedient follow-up and referral to a musculoskeletal oncologist when appropriate, are essential.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.3
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• pp.176-185
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• 2023

Facebow transfer is essential for accurately mounting a dental cast onto a semi-adjustable articulator. The precision of traditional analog facebow transfer is influenced by both the accuracy of the equipment used and the skill level of the operator. Considering that substantial positional deviations can adversely affect the quality of a fabricated dental prosthesis; it is critical to assess the positional accuracy of casts mounted using analog facebow transfer. This case report evaluates the linear and angular deviations of the occlusal plane for maxillary casts mounted through both analog facebow transfer and cone-beam computed tomography-based methods. The findings indicate that analog facebow transfer produced a linear deviation ranging from 3 to 16 mm and an angular deviation of the occlusal plane between 5 to 7 degrees. This case report confirms that, across two patients, analog facebow transfer can result in varying degrees of positional deviation, thereby potentially leading to inaccuracies in the fabrication of dental prostheses. These results suggest that, in clinical practice, the use of analog facebow transfer may yield significant deviations during the process of mounting maxillary casts.

• Journal of Gastric Cancer
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• v.8 no.2
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• pp.57-64
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• 2008

In gastric cancer, the only potentially curative treatment is surgery that attempts to achieve curative (R0) resection. However, despite the use of curative resection, a recurrence develops in a high percentage of patients, especially in cases of serosa and/or lymph node involvement. As a strategy to improve the survival of the patients with resectable advanced gastric cancer, neoadjuvant chemotherapy has been evaluated in several phase II trials and a few phase III trials. The results of these trials have confirmed the feasibility and safety of this approach with no apparent increase in surgical complications. Recently, the findings of a large phase III randomized trial (MAGIC trial) have indicated that compared to the use of surgery alone, perioperative chemotherapy, using both a neoadjuvant and adjuvant strategy, decreased the number of T and N stage cancers and improved survival. The results of another recent phase III trial (FNLCC 94012/FFCD 9703) also showed that compared to the use of surgery alone, perioperative chemotherapy improved the R0 resection rate and survival. In both trials, the improved outcomes may be attributed to the use of neoadjuvant chemotherapy because of poor compliance with adjuvant chemotherapy. These results cannot be directly translated to clinical practice in Korea due to differences in surgical techniques and outcomes. However, the findings of a few small phase II and III trials performed in patients with locally advanced gastric cancer in Korea have also suggested that neoadjuvant chemotherapy would result in the improvement of the R0 resection rate and down-staging of the disease. More effective chemotherapy regimens are needed in future large randomized trials to determine the subset of patients that will benefit from neoadjuvant chemotherapy and to determine the extent of benefit.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.3
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• pp.185-193
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• 2015

The purpose of this study was to demonstrate clinical effects on cognition, visual perception, depression, anxiety, and activities of daily living by applying the N-BACK program, a brain stimulated training program, which is used for the clinical purpose. To prove this, subjects suspected of cognitive impairment with 18-23 points in a Korean version of mental status examination (MMSE-K) were recruited among the population who had been diagnosed with stroke duration and suffered from it for six months of duration, and 10 of the subjects were selected into the experimental group and the control group, respectively. A total of 20 sessions were carried out for 30 minutes per day 5 times for 4 weeks. As a result, the experimental group who has been applied the N-BACK program showed positive results in the improvement of cognition, visual perception, depression, anxiety, and daily living skills. The results obtained from this study expect us that applying the N-BACK program for the improvement of cognition, visual perception, depression, and anxiety to stroke patients has a positive effect on the rehabilitation of patients and will lead them to improve daily living activities more independently.

• Journal of Agricultural Extension & Community Development
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• v.4 no.1
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• pp.41-56
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• 1997

1970년대 이후 도시 중심의 급속한 공업화 정책을 추진한 결과, 농촌의 저발전 문제에 직면하고 있다. 1980년대 중반부터 이에 대한 대응전략으로서 농공단지 개발을 통한 산업유치, 농산물 가공산업 개발 및 유통체계 개선, 관광농업 개발 등이 논의되어 왔다. 오늘날에 와서는 WTO 체제 하에서 농산물 무역자유화가 보편적인 규범으로 자리잡아 가면서 이러한 변화를 더욱 재촉하고 있다. 이 글의 목적은 농공단지와 관광농원을 중심으로 우리 나라 농산업 발전과정을 고찰하고, 향후 발전 방향을 제시하는 데 있다. 농공단지와 관광농원 육성사업의 특성과 성패요인을 분석하는 데 있어서 이용된 자료는 주로 2차자료이다. 농공단지조성사업의 성과에 대한 많은 논란에도 불구하고, 개량적인 지표는 그것이 농촌지역경제 활성화에 직간접적으로 공헌하였음을 보여준다. 농촌노동력의 66.1%를 고용하고, 이들에게 1인당 월 평균 70만원 이상의 소득을 제공해 주었으며, 서비스업 등 관련산업의 성장에도 영향을 미쳤기 때문이다. 그러나 농공단지조성사업은 많은 문제점도 안고 있다. 농촌지역에 숙련 노동자가 부족하며 직업훈련 기회 및 창업지원 프로그램이 도시지역에 집중되어 있다. 또한 입주 기업이 농산물이나 골재 등 현지 자원을 활용하는 경우가 매우 적은 것으로 나타나고 있다. 이에 대한 대응책으로서 농촌 주민들이 손쉽게 참여할 수 있는 직업훈련 프로그램을 개발하여 제공해야 하며, 경영과 시장정보 분석 등을 기술적으로 지원할 수 있는 효과적인 지도체계를 구축해야 한다. 관광농업은 새롭게 떠오르는 산업이다. 아직 기반이 취약하지만 국가 경제성장과 도시화 진행 추이에 비추어 볼 때 관광농원은 점차 증가할 것으로 전망된다. 하지만 이 산업의 지속적인 발전을 위해서는 정책의 유연성을 확보해야 하고, 농원운영자의 경영능력이 향상되어야 하며, 수요의 계절성을 극복해야 하는 등의 과제를 안고 있다. 또한 공동운영 형태의 농원에 있어서는 참여자들을 효과적으로 조직하고, 토지소유권 분쟁을 해소해야 하는 문제가 있다. 무엇보다도 아직 이 산업의 기반이 취약하다는 전제 위에 점진적이고 지속적인 재정과 기술지원이 요청되고 있다. 다양한 운영 프로그램의 개발과 지역내 네트웍 형태의 연계개발 방식의 채택이 필요하며, 관광농원이나 농어촌휴양지 개발지역에서는 산업개발 및 주거지 개발계획이 관광여건 조성과 총체적으로 연계되어야 할 것이다.

• The Journal of the Korean bone and joint tumor society
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• v.13 no.2
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• pp.135-141
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• 2007

Nodular faciitis is generally considered to be benign proliferation of fibroblasts and myoblasts, and it measures dimension up to 3cm. The characteristics such as rapid growth, abundant cellularity, and mitotic activity occasionally cause these lesions to mimic sarcoma. The authors experienced two cases of nodular fasciitis of the thigh, which were unusually large with dimension of more than 5cm. All of these two cases mimicked sarcoma and one of two cases, which initially mimicked sarcoma clinically and histologically in our hospital, was finally diagnosed as nodular fasciitis after requesting external consultation to several experienced pathologists. All of two cases had no evidence of recurrence at 2 years postoperatively. The lesions of unusually large dimension such as in our cases must be included in the differential diagnosis of soft tissue sarcoma. So we report two cases of nodular fasciitis of the thigh with a review of the current literature.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.92-101
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• 2009

Purpose: Scintimammography is one of the screening tests for the early diagnosis of breast cancer. It has been widely accepted as very useful in assessing masses that have not been detected in breast scanning. This method is highly sensitive and specific with respect to the diagnosis of primary and relapsing breast cancer. It has some difficulties, however, in detecting tumors sized 1 cm and below due to the radioactivity around the breast and the geometrical structure of the equipment. The recent introduction of high-resolution Breast-specific Gamma Imaging (BSGI) has made it possible to more accurately discriminate between malignant and benign tumors than with any other test method. Thus, the possibility of an unnecessary biopsy being performed has decreased. The purpose of this study was to examine the diagnostic capacity of mammography, breast sonography, and scintimammography, which are used for the early diagnosis of known breast cancer, and of BSGI, and to evaluate the skillfulness of radiologists. Materials and Methods: The 53 volunteers participants who had no clinical manifestation of breast cancer underwent the BSGI in February 2009. In the BSGI procedure, scanning images were obtained from the craniocaudal projection (CC) and the mediolateral Oblique projection (MLO), as well as from the additional $80{\times}80$-matrix-sized views at various angles in the Present Time method, 10 minutes after the 25 mCi $^{99m}Tc$-MIBI was injected. Results: The results of the BSGI showed that two participants had masses in their breast tissue. As the results of the diagnosis of four participants were not clear, they were retested and the results of the second test were negative. The results of the clinical screening test for breast cancer showed that the sensitivity of BSGI, scintimammography, mammography, and breast sonography was 86.5%, 77.8%, 85~90%, and 66.7%, respectively, and that their specificity was 92.4%, 84.2%, 20~42%, and 68%, respectively. Conclusion: The autodiagnosis and breast cancer screening test are needed for the early diagnosis of breast cancer. It was not easy, however, to accurately determine the presence of a mass in the breast using the existing breast cancer screening test. The patients with unclear test findings were made to undergo a histologic biopsy for a more accurate diagnosis. It is expected that the BSGI can provide useful information for the early diagnosis of breast cancer and of primary breast cancer, and will reduce the performance of unnecessary biopsies because of its higher sensitivity and specificity than existing breast cancer screening tests.