A testing methodology for suck-back behavior of high-speed air-turbine dental handpiece

Ying-Jun Quan(전영준),Joong-Yeon Lim(임중연),Kyoung-Nam Kim(김경남),Yang-Soo Kim(김양수) 대한치과재료학회 2015 대한치과재료학회지 Vol.42 No.1

치과용 고속 에어터빈 핸드피스는 압축공기를 이용하여 핸드피스 헤드 내부의 임펠러를 구동시키는 치아절삭에 사용되는 치과용 의료기기이다. 압축공기의 유동특성에 따른 압력 변화로 인하여 고속 치과용 에어터빈 핸드피스는 사용 중 기체 흡입 현상이 발생하는데 이런 현상을 에어터빈 핸드피스의 suck-back 현상이라고 한다. Suck-back 현상 때문에 치료 시 환자 구강 내의 혈액, 박테리아 등 유해물질이 핸드피스의 내부로 흡입되는데 치과용 에어티빈 핸드피스는 일회용 의료기기가 아니므로 여러 환자들한테 사용될 때 설령 소독하더라도 교차감염(cross-infection)의 위험이 발생하게 된다. 하지만 suck-back 현상에 대해 평가하는 연구가 아직 많이 부족한 상태이다. 연구에서는 suck-back을 방지할 수 있는 기능으로 설계된 상용화 된 5개 제품의 핸드피스에 대해 특별히 제작된 측정 장치를 이용하여 suck-back 성능을 평가하였다. 실험은 측정하려는 5사 제품의 구동 시 최대 압력, 정지 순간의 최소 압력을 측정하고 suck-back 현상이 지속되는 시간을 측정하였다. 실험 결과 A사 제품은 최소 압력이 0 bar로써 suck-back 현상이 발생하지 않았다. 반면 기타 4사의 제품은 suck-back 현상이 발생하였는데 그 중 B사 제품은 평균값 -0.00bar(-0.01bar부터 0bar 사이의 값), E사 제품은 -0.01(0)bar, C사 제품은 -0.019(0.003)bar, D사 제품은 -0.04(0)bar의 결과를 보였다. 또한 suck-back 현상의 지속 시간은 B사 제품이 1.83초로 가장 오래 유지되었으며 그 다음으로 D사 제품이 1.82초, E사 제품은 1.56초, C사 제품은 1.30초, 그리고 A사 제품은 0초로 가장 짧았다. 실험 결과 본 연구에서 고안한 에어터빈 핸드피스의 suck-back 현상 시험 방법은 정량적으로 측정할 수 있을 것으로 사료되었다.

Current Applications and Development of Composite Manufacturing Processes for Future Mobility

Jun Young Choi,Ji Ho Jeon,Jang Hyeon Lyu,Jungwoo Park,Geun Young Kim,Suk Young Chey,Ying-Jun Quan,Binayak Bhandari,Gangadhara Prusty,Sung-Hoon Ahn 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1

The acceleration of environmental pollution and global warming has resulted in increased environmental awareness and regulations to reduce carbon emissions. As the automotive industry is evolving from internal combustion engine (ICE) vehicles to electric vehicles (EVs) and urban air mobility (UAM), composites have gained attraction for increased driving range and green mobility. However, composites, acclaimed to be an alternative to metals for its reduced weight and high mechanical properties, have not achieved successful mass adoption due to the tradeoff in performance and cost. While legislation is continuously being updated to tackle environmental concerns, automotive original equipment manufacturers (OEMs) have been hesitant to apply composite technology to mainstream vehicles, largely due to economic reasons. Therefore, latest developments have been focused on application of biodegradable composites and integration of robotic automation into composite manufacturing processes for eco-friendly, sustainable, cost-effective production. This paper reviews the latest applications of composite materials into modern vehicles and evaluates state of the art of composite manufacturing and recycling processes for green mobility.

Chipless RFID Sensor Printing Using Aerodynamically Focused Nanoparticle Printing System

S. H. Min(민수홍),Ying-Jun Quan,H. J. Kim(김호진),G. Y. Lee(이길용),S. H. Ahn(안성훈) Korean Society for Precision Engineering 2019 한국정밀공학회 학술발표대회 논문집 Vol.2019 No.10월

Two Luminescent Cd(II) Coordination Polymers: Enhancement Activity on Pancreatic Cancer Combined with Biliary Stent Placement and 125I Particles

Jie-Peng Jia,Quan Shao,Ying-Kai Wang,Bo Qian,Wen Zhang,Tao Hu,Ji-Jun Zhang 한국고분자학회 2021 Macromolecular Research Vol.29 No.11

With the reaction between bib ligands, 5-substituted isophthalic acid and Cd(II) ions, we produced two coordination polymers in success, that is, [Cd(5-meo-ip) (bib)0.5]n (2) and [Cd(5-me-ip)(bib)(H2O)]n·n(H2O) (1) (bib is 1,4-bis(imidazoly)butane, 5-meo-H2ip is 5-methoxyisophthalic acid, and 5-me-H2ip is 5-methylisophthalic acid). The luminescent performances and thermal stability of the two compounds were also explored. Their anti-pancreatic cancer activity combined with biliary stent placement and 125I particles was evaluated and the specific mechanism was explored as well. Firstly, after the model construction and compound treatment, the weight and volume of the tumor tissue was measured. Next, the apoptosis level of the cancer cells were evaluated with Annexin V-FITC/PI apoptosis assay.

Diagnostic Significance of Combined Detection of Epstein-Barr Virus Antibodies, VCA/IgA, EA/IgA, Rta/IgG and EBNA1/IgA for Nasopharyngeal Carcinoma

Cai, Yong-Lin,Li, Jun,Lu, Ai-Ying,Zheng, Yu-Ming,Zhong, Wei-Ming,Wang, Wei,Gao, Jian-Quan,Zeng, Hong,Cheng, Ji-Ru,Tang, Min-Zhong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

The objective of this study was to investigate the diagnostic significance of EBV antibody combined detection for nasopharyngeal carcinoma (NPC) in a high incidence region of southern China. Two hundred and eleven untreated NPC patients, 203 non-NPC ENT patients, and 210 healthy controls were recruited for the study. The titers of VCA/IgA and EA/IgA were assessed by immunoenzyme assay, and the levels of Rta/IgG and EBNA1/IgA were determined by enzyme-linked immunosorbent assay. The levels of VCA/IgA, EA/IgA, Rta/IgG and EBNA1/IgA demonstrated no association with gender or age (p>0.05). The receiver operating characteristic curve and the area under the curve were used to evaluate the diagnostic value. The sensitivity of VCA/IgA (98.1%) and the specificity of EA/IgA (98.5%) were the highest. When a logistic regression model was used to combine the results from multiple antibodies to increase the accuracy, the combination of VCA/IgA+Rta/IgG, whose area under the curve was 0.99, had the highest diagnostic efficiency, and its sensitivity, specificity and Youden index were 94.8%, 98.0% and 0.93 respectively. The data suggest that the combination of VCA/IgA+Rta/IgG may be most suitable for NPC serodiagnosis.

Assessing the Diagnostic Value of Serum Dickkopf-related Protein 1 Levels in Cancer Detection: a Case-control Study and Meta-analysis

Jiang, Xiao-Ting,Ma, Ying-Yu,Guo, Kun,Xia, Ying-Jie,Wang, Hui-Ju,Li, Li,He, Xu-Jun,Huang, Dong-Sheng,Tao, Hou-Quan Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.21

Background: This study aimed to summarize the potential diagnostic value of serum DKK1 levels in cancer detection. Materials and Methods: Serum DKK1 was measured using enzyme-linked immunosorbent assay in a case-control study. Then we performed a meta-analysis and the pooled sensitivity, specificity, diagnostic odds ratio, and summary receiver operating characteristic (sROC) curves were used to evaluate the overall test performance. Results: Serum DKK1 levels were found to be significantly upregulated in gastric cancer as compared to controls. ROC curve analysis revealed an AUC of 0.636, indicating the test has the potential to diagnose cancer with poor accuracy. The summary estimates of the pooled sensitivity, specificity and diagnostic odds ratio in meta-analysis were 0.55 with a 95% confidence interval (CI) (0.53-0.57), 0.86 (95%CI, 0.84-0.88) and 12.25 (95%CI, 5.31-28.28), respectively. The area under the sROC was 0.85. Subgroup analysis revealed that the diagnostic accuracy of serum DKK1 in lung cancer (sensitivity: 0.69 with 95%CI, 0.66-0.74; specificity: 0.95 with 95%CI, 0.92-0.97; diagnostic odds ratio: 44.93 with 95%CI, 26.19-77.08) was significantly higher than for any other cancer. Conclusions: Serum DKK1 might be useful as a noninvasive method for confirmation of cancer diagnosis, particularly in the case of lung cancer.

Experimental Study on Magnesium Sulfate Cement Concrete Splices of Widened Box Girder

Li-fang Zhang,Jun Yan,Hai-yan Ma,Hong-fa Yu,Ying Wang,Qi-quan Mei 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.12

The connecting part of bridge widening undertakes complicated forces and tends to crack. Basic magnesium sulfate cement concrete has excellent properties such as ideal early strength and tensile strength, meeting the performance requirements of joint materials. Experiments of two spliced box girder specimens with C40 basic magnesium sulfate cement concrete (MC) and normal Portland cement concrete (NC) as joint materials are carried out. Concrete strain, reinforcement strain, deflection and crack propagation law of the joint section are tested and analyzed under symmetrical loading at the cantilever of the box girders. The study shows when MC material is used in the splicing section, the joint section showed a multi-cracks failure mode with an ultimate load ratio of 0.99 and a maximum crack width of 1.3 mm; NC joint section has only three longitudinal cracks with an ultimate load ratio of 0.97 and a maximum crack width of 0.98 mm. Under the same load, the crack width and the deflection of mid-span MC joint section are greater than which of NC joint section. The maximum deflection of NC splicing section is 1.20 mm, which is 1/633 of the calculating span length. The maximum deflection of MC spliced section is 2.03 mm, which is 1/374 of the calculating span length. Comparison of the maximum deflection and the maximum crack width shows that MC material has better ductility.

Lithography-free and Highly Angle Sensitive Structural Coloration Using Fabry–Perot Resonance of Tin

Young-Gyun Kim,Ying-Jun Quan,Min-Soo Kim,Younggyun Cho,Sung-Hoon Ahn 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.3

Recently, there has been much interest in applying the color changes of nano-patterned structures to sensor technology. However, the lithographic nano-patterning process is not environmentally friendly, and it is difficult to fabricate large areas of color due to limitations associated with this approach. In this study, we realized a highly tunable structural coloration based on a Fabry–Perot interferometer design that does not require nano-patterning processes. To increase the reflected color change according to the angle, a color element using an asymmetric metal–insulator–metal structure was applied, fabricated using silver–silicon dioxide–tin (Sn), respectively. Using the optical properties of Sn, we maximized the change in reflection color and realized three primary colors of subtractive color of cyan, magenta and yellow according to the angle of designed MIM structure. Theoretical and experimental results revealed that the color and intensity of the reflectance depended strongly on the angle of the reflective surfaces. The manufacturing process is simple and yields large surfaces of high quality. Based on this premise, we fabricated a soft robot capable of color camouflage, and an angle-detecting color sensor for inspecting the three-dimensional shape quality of curved glass with a high sensitivity of 1.8 nm/degree. In addition, we propose a shape evaluation method by color, spectrometry, and monochromatic light.

A review on fabrication processes for electrochromic devices

Park, Sung-Ik,Quan, Ying-Jun,Kim, Se-Heon,Kim, Hyungsub,Kim, Sooyeun,Chun, Doo-Man,Lee, Caroline S.,Taya, Minoru,Chu, Won-Shik,Ahn, Sung-Hoon SPRINGER 2016 INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND Vol. No.

Prevalence and Risk Factors of Cerebral Small Vessel Disease in a Chinese Population-Based Sample

Fei Han,Fei-Fei Zhai,Quan Wang,Li-Xin Zhou,Jun Ni,Ming Yao,Ming-Li Li,Shu-Yang Zhang,Li-Ying Cui,Zheng-Yu Jin,Yi-Cheng Zhu 대한뇌졸중학회 2018 Journal of stroke Vol.20 No.2

Background and Purpose Epidemiological data of cerebral small vessel disease (CSVD) in the general population of China are lacking. We report on the prevalence of lacunes, white matter hyperintensity (WMH), and cerebral microbleeds (CMBs) in a community-based sample in China and compare the results with those of other studies. Methods This was a cross-sectional analysis of the population-based Shunyi Study in China. A total of 1,211 stroke-free participants (mean age, 55.6±9.3 years; 37.4% men) with available 3 Tesla (3T) magnetic resonance images were included in this analysis. Demographic information and risk factor data were assessed. The overall and age-specific prevalence of lacunes, WMH, and CMBs was evaluated. Associations between cardiovascular risk factors and the presence of these lesions were analyzed by multiple logistic regression. Results Our study showed a prevalence of 14.5% for lacunes, 72.1% for periventricular hyperintensity (PVH), 65.4% for deep white matter hyperintensity (DWMH), and 10.6% for CMBs. When compared with other community-based samples, individuals in the same age group showed a higher burden of lacunes and a relatively lower prevalence of CMBs. Advanced age was independently associated with the prevalence of these CSVD markers, while the presence of hypertension increased the risk of lacunes, PVH/DWMH, and CMBs in deep or infratentorial locations. Conclusions A higher burden of lacunes but a relatively lower prevalence of CMBs was observed in this Chinese population. This notable result highlights the challenge of CSVD prevention in China. Chinese have a risk factor profile for CSVD similar to those in other populations.