• 한국재료학회지
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• 제17권3호
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• pp.152-159
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• 2007

When the electronics are tested with thermal shock for Pb-free solder joint reliability, there are temperature conditions with use environment but number of cycles for test don't clearly exist. To obtain the long term reliability data, electronic companies have spent the cost and times. Therefore this studies show the test method and number of thermal shock cycles for evaluating the solder joint reliability of electronic components and also research bonding strength variation with formation and growth of intermetallic compounds (IMC). SMD (surface mount device) 3216 chip resistor and 44 pin QFP (quad flat package) was utilized for experiments and each components were soldered with Sn-40Pb and Sn-3.0 Ag-0.5 Cu solder on the FR-4 PCB(printed circuit board) using by reflow soldering process. To reliability evaluation, thermal shock test was conducted between $-40^{\circ}C\;and\;+125^{\circ}C$ for 2,000 cycles, 10 minute dwell time, respectively. Also we analyzed the IMCs of solder joint using by SEM and EDX. To compare with bonding strength, resistor and QFP were tested shear strength and $45^{\circ}$ lead pull strength, respectively. From these results, optimized number of cycles was proposed with variation of bonding strength under thermal shock.

• Journal of Periodontal and Implant Science
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• 제37권2호
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• pp.193-200
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• 2007

During periodontal examination and periodontal recall visit, patients might feel pain. Probing with 0.45mm diameter probe, "overprobing" into connective tissue underlying periodontal pocket could be the primary aspect of pain. The purpose of present study, performed during recall visit, was to compare the levels of pain experienced by patients during periodontal probing using probes with the tip diameter of either 0.45mm or 0.63mm. Twenty patients were enrolled: 3 periodontists each exammined 20 patients at the Dankook university dental hospital. in each patient at six sites per tooth, diagonal maxillary/mandibular quad-rants were probed with 0.45mm diameter and 0.63mm diameter probe. Lower pain responses following probing with the 0.63mm diameter probe as compared to the 0.45mm probe were observed for patients of therapist 2 and the upper VAS quartile Groups(P<0.05). For therapist 1 and 3 groups, no differences were found. Patient worry about the pain while dental treatment procedures. If therapist use 0.63mm diameter probe while periodontal examination and recall visit, the patient's pain and discomfort could be reduced. Therefore, patient will cooperate more during the treatment, which leads to a better result. Dental therapists should make an effort to minimize the degree of discomfort during treatment. Dental therapist periodically should evaluate this part of their skill by asking patients and promote this skill.

• 항공우주시스템공학회지
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• 제11권4호
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• pp.36-43
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• 2017

쿼드틸트 무인기에 적용되는 프롭로터 블레이드 형상 최적설계를 수행하였다. 형상 최적설계 프로세스 통합은 ModelCenter(R) 프로그램을 이용하였으며, 최적설계 과정에서 성능해석은 CAMRAD-II를 사용하였다. 목적함수는 제자리비행 및 전진비행 모드에서 성능효율 최대화로 설정하였으며, 제한조건은 소요 동력 및 피치로드 하중 값이 기본 형상 값보다 작게 되도록 설정하였다. 설계변수로는 블레이드 루트 코드길이, 테이퍼비, 비틀림 각의 기울기 및 각도, 하반각, 끝단 형상 생성을 위한 파라볼릭 계수, 하반각과 끝단형상이 적용되는 블레이드 스팬위치, 블레이드 단면을 구성하는 익형의 위치로 구성하였다. 최적 설계 결과 기준 형상 대비 제자리비행 효율은 1.6%, 전진 비행 효율은 13.6% 향상된 프롭로터 블레이드 형상을 도출할 수 있었으며, 피치로드 하중은 약 30% 감소하였다.

• 한국항공우주학회지
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• 제46권7호
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• pp.527-534
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• 2018

본 논문은 최근에 각광 받고 있는 드론(멀티콥터)과 관련하여 비행체의 비행 성능, 특히 비행 가능 시간에 대한 예측과 실험 데이터를 통한 검증 등을 목표로 하여, 제자리 비행에 대한 연구 결과를 제시 하고 있다. 연구 방법을 드론 시스템을 구성하고 있는 여러 부품들을 기능별로 분류하여 부품 수준에서의 제원과 기능에 대한 정리 및 수학적 수식화를 통하여 단위 부품의 성능을 분석 및 실험 데이터를 확보하고, 이들 단위 부품 데이터의 조합을 통하여 드론 시스템의 제자리비행 성능을 예측하는 연구 결과를 보여 주고 있다. 또한 5kg급 쿼드콥터를 이용하여 제자리 비행에 대한 분석을 통하여 비행시간에 따른 전압 변화를 예측, 검증 하였으며 해당 방법을 통해 제자리 비행시간을 예측하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권17호
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• pp.7443-7447
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• 2014

Aim: Little is known about the genetic associations with Basal cell carcinoma (BCC) risk in non-Caucasian populations, in which BCC is rare, as in Korea. We here conducted a pilot genome-wide association study (GWAS) in 12 patients and 48 standard controls. Method: A total of 263,511 SNPs were analyzed with the Illumina HumanOmni1 Quad v1.0 DNA Analysis BeadChip for cases and Korean HapMap 570K for controls. Results: SNP-based analyses, based on the allele genetic model with adjustment for sex and age showed suggestive associations with BCC risk for 6 SNPs with a P-value (P < 0.0005). However, these associations were not statistically significant after Bonferroni correction: rs1040503, rs2216491, rs13407683, rs4751072, rs9891263, and rs1368474. In addition, results from gene-based analyses showed suggestive associations with BCC risk for 33 candidate genes with a P-value (P <0.0005). Consistent with previous GWAS and replication studies in Caucasian populations, PADI6, RHOU and SLC45A2 were identified as having null associations with BCC (P > 0.05), likely due to the smaller sample size. Conclusions: Although this was a small-scale negative study, to our knowledge, we have conducted the first GWAS for BCC risk in an Asian population. Further large studies in non-Caucasian populations are required to achieve statistical significance and confirm these findings.

• 한국정보통신학회논문지
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• 제21권9호
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• pp.1703-1710
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• 2017

본 논문에서는 디지털 홀로그래픽 서비스를 위한 3D 공간정보 (깊이정보) 보안기술을 제안한다. 영상 콘텐츠 암호화는 영상의 전체 혹은 일부분을 조작하여 허용된 사용자에게만 정보를 제공하는 기술이다. 제안하는 암호화 기술은 깊이정보에서 객체의 윤곽선을 추출한 후 이를 기반으로 쿼드트리 분할을 수행한다. 분할된 블록 중 최상위 블록을 암호화 한다. 암호화 효과는 화질측정 방법을 이용한 정량적인 평가와 시각적인 평가를 병행하였다. 실험결과 전체 데이터 중에서 0.43%의 데이터만을 암호화하여 깊이정보의 시각적인 정보를 은닉할 수 있었다. 또한, 암호화되는 데이터 량과 시각적인 특성분석을 통해 깊이정보의 윤곽선 추출시 사용하는 임계치 값과 암호화 효율 상의 상관관계를 분석하였다.

• Journal of Korean Neurosurgical Society
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• 제50권6호
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• pp.486-491
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• 2011

Objective : Structural genetic variation, including copy-number variation (CNV), constitutes a substantial fraction of total genetic variability, and the importance of structural variants in modulating susceptibility is increasingly being recognized. CNV can change biological function and contribute to pathophysiological conditions of human disease. Its relationship with common, complex human disease in particular is not fully understood. Here, we searched the human genome to identify copy number variants that predispose to moya-moya type cerebrovascular disease. Methods : We retrospectively analyzed patients who had unilateral or bilateral steno-occlusive lesions at the cerebral artery from March, 2007, to September, 2009. For the 20 subjects, including patients with moyamoya type pathologies and three normal healthy controls, we divided the subjects into 4 groups : typical moyamoya (n=6), unilateral moyamoya (n=9), progression unilateral to typical moyamoya (n=2) and non-moyamoya (n=3). Fragmented DNA was hybridized on Human610Quad v1.0 DNA analysis BeadChips (Illumina). Data analysis was performed with GenomeStudio v2009.1, Genotyping 1.1.9, cnvPartition_v2.3.4 software. Overall call rates were more than 99.8%. Results : In total, 1258 CNVs were identified across the whole genome. The average number of CNV was 45.55 per subject (CNV region was 45.4). The gain/loss of CNV was 52/249, having 4.7 fold higher frequencies in loss calls. The total CNV size was 904,657,868, and average size was 993,038. The largest portion of CNVs (613 calls) were 1M-10M in length. Interestingly, significant association between unilateral moyamoya disease (MMD) and progression of unilateral to typical moyamoya was observed. Conclusion : Significant association between unilateral MMD and progression of unilateral to typical moyamoya was observed. The finding was confirmed again with clustering analysis. These data demonstrate that certain CNV associate with moyamoya-type cerebrovascular disease.

• Clinical and Experimental Reproductive Medicine
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• 제44권2호
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• pp.63-72
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• 2017

Objective: Hyperstimulation methods are broadly used for in vitro fertilization (IVF) in patients with infertility; however, the side effects associated with these therapies, such as ovarian hyperstimulation syndrome (OHSS), have not been well studied. N-glycoproteomes are subproteomes used for the remote sensing of ovarian stimulation in follicular growth. Glycoproteomic variation in human follicular fluid (hFF) has not been evaluated. In this study, we aimed to identify and quantify the glycoproteomes and N-glycoproteins (N-GPs) in natural and stimulated hFF using label-free nano-liquid chromatography/electrospray ionization-quad time-of-flight mass spectrometry. Methods: For profiling of the total proteome and glycoproteome, pooled protein samples from natural and stimulated hFF samples were selectively isolated using hydrazide chemistry to obtain the total proteomes and glycoproteomes. N-GPs were validated by the consensus sequence N-X-S/T (92.2% specificity for the N-glycomotif at p<0.05). All data were compared between natural versus hyperstimulated hFF samples. Results: We detected 41 and 44 N-GPs in the natural and stimulated hFF samples, respectively. Importantly, we identified 11 N-GPs with greater than two-fold upregulation in stimulated hFF samples compared to natural hFF samples. We also validated the novel N-GPs thyroxine-binding globulin, vitamin D-binding protein, and complement proteins C3 and C9. Conclusion: We identified and classified N-GPs in hFF to improve our understanding of follicular physiology in patients requiring assisted reproduction. Our results provided important insights into the prevention of hyperstimulation side effects, such as OHSS.

• Genomics & Informatics
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• 제16권2호
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• pp.36-41
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• 2018

Kawasaki disease (KD) is an acute febrile vasculitis predominately affecting infants and children. The dominant incidence age of KD is from 6 months to 5 years of age, and the incidence is unusual in those younger than 6 months and older than 5 years of age. We tried to identify genetic variants specifically associated with KD in patients younger than 6 months or older than 5 years of age. We performed an age-stratified genome-wide association study using the Illumina HumanOmni1-Quad BeadChip data (296 cases vs. 1,000 controls) and a replication study (1,360 cases vs. 3,553 controls) in the Korean population. Among 26 candidate single nucleotide polymorphisms (SNPs) tested in replication study, only a rare nonsynonymous SNP (rs4365796: c.1106C>T, p.Thr369Met) in the lymphoid enhancer binding factor 1 (LEF1) gene was very significantly associated with KD in patients younger than 6 months of age (odds ratio [OR], 3.07; $p_{combined}=1.10{\times}10^{-5}$), whereas no association of the same SNP was observed in any other age group of KD patients. The same SNP (rs4365796) in the LEF1 gene showed the same direction of risk effect in Japanese KD patients younger than 6 months of age, although the effect was not statistically significant (OR, 1.42; p = 0.397). This result indicates that the LEF1 gene may play an important role as a susceptibility gene specifically affecting KD patients younger than 6 months of age.