가전제품의 내부용적 계산을 위한 구멍메움 알고리즘

Jianhui Fu,박래성(Raesung Park),박민근(Mingeun Park),정융호(Yoongho Jung) (사)한국CDE학회 2016 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2016 No.동계

Refrigerator has been used across the various fields in society as a device for keeping cold foods or medications. As the refrigeration technology advances, important issue such as enlargement has been arised. It is therefore important that the design having a maximum internal space volume in a limited space are very important. The internal space of refrigerator is consisted of a component such as a door and the inner case. The volume calculation of that is performed by a Boolean operation function of the 3D CAD software. However, many pre-processing operations by the user, such as hole filling and construction closed space by filling in the gaps between parts take a lot of time. In this research, we developed a decomposition modelbased automatic volume calculation program of refrigerator internal space satisfying the interior volume measurement standard. Though we have developed the program by applying to refrigerator assembly, application of the program can be extended to the assembly made up of many parts.

Neuroprotective Effects of Luteolin Against Spinal Cord Ischemia–Reperfusion Injury by Attenuation of Oxidative Stress, Inflammation, and Apoptosis

Jian Fu,Haibin Sun,Yongzhe Zhang,Wei Xu,Chuan Wang,Yanwei Fang,Jianhui Zhao 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.1

Luteolin (LU) is a widely distributed flavonoid with multitarget effects. The objective of this study was to determine whether LU could reduce the ischemia–reperfusion injury of the spinal cord (SCII) in a rat model. Forty-eight rats were divided into four groups: sham, SCII, SCII+L-LU (50 mg/kg), and SCII+H-LU (100 mg/kg). Abdominal aortic occlusion was carried out for 40 min in all groups. Hindlimb motor functions were evaluated using the Tarlov scoring system. Nissl and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL) staining were used to detect cell survival and apoptosis in the spinal cord. Spinal cord samples were taken for determination of malondialdehyde, xanthine oxidase, superoxide dismutase, and glutathione peroxidase activities. The levels of tumor necrosis factor-α, interleukin (IL)-1β, and IL-18 were assessed using ELISA kits to examine the inflammatory responses in the spinal cord. Western blot analysis was used to examine the expression of nuclear factor erythroid 2-related factor (Nrf2) and nod-like receptor pyrin domain-containing 3 protein (NLRP3) levels. We found that LU pretreatment significantly improved the locomotor function of rats after SCII, increased neuron survival, and inhibited apoptosis in the spinal cord. Furthermore, the oxidative stress and inflammatory response were significantly suppressed upon treatment with LU. Finally, LU upregulated Nrf2 levels and downregulated NLRP3 protein expression in SCII tissues. Thus, LU exhibited a neuroprotective effect following SCII by alleviating oxidative stress and inhibiting inflammatory responses and cell apoptosis. The possible mechanism may be related to the activation of Nrf2 and inhibition of NLRP3 inflammasome pathway.

Luteolin Modulates the NF-E2-Related Factor 2/Glutamate–Cysteine Ligase Pathway in Rats with Spinal Cord Injury

Jian Fu,Wei Xu,Yongzhe Zhang,Haibin Sun,Jianhui Zhao 한국식품영양과학회 2021 Journal of medicinal food Vol.24 No.3

Spinal cord ischemia–reperfusion injury (SCII) easily causes unalterable neurological deficits. We previously demonstrated that the flavonoid luteolin (LU) has strong antioxidant, anti-inflammatory, and other neuroprotective efficacies against SCII. In our current study, we examined the contributions of the NF-E2-related factor 2 (Nrf2)/glutamate–cysteine ligase (GCL) pathway to LU-mediated neuroprotection in the transient abdominal aorta occlusion rat model of SCII. Rats were divided into four groups: Sham surgery, SCII alone, SCII plus LU pretreatment (SCII + LU), and SCII plus cotreatment with LU and the Nrf2 inhibitor ML385 (SCII + LU + ML385). The Basso–Beattie–Bresnahan (BBB) scale was used to assess neurological function, hematoxylin and eosin staining to evaluate pathological change to the spinal cord, and enzyme-linked immunosorbent assay to measure tissue markers of oxidative stress and inflammation induced by SCII. Mitochondrial injury and apoptosis were examined by flow cytometry and expression levels of Nrf2, GCL catalytic subunit (GCLc), and GCL modifier subunit (GCLm) by real-time quantitative polymerase chain reaction. LU pretreatment significantly enhanced recovery of motor function as evidenced by the BBB score and attenuated the pathological damage. Furthermore, LU effectively enhanced the antioxidative activity, alleviated mitochondrial swelling, decreased the expression levels of several proinflammatory cytokines after SCII, and significantly upregulated Nrf2, GCLc, and GCLm expression levels. Cotreatment with ML385 reversed all these protective effects of LU except the anti-inflammatory response. Collectively, these findings indicate that the neuroprotective efficacy of LU depends on suppression of oxidative stress and preservation of mitochondrial function through signaling pathways involving Nrf2 activation and downstream gene expression.

DEVELOPMENT OF A BACKFLOW SIMULATION PROGRAM FOR AUTOMOTIVE BODY ASSEMBLIES

윤재덕,이성훈,Jianhui Fu,정융호 한국자동차공학회 2017 International journal of automotive technology Vol.18 No.4

Most car body parts are manufactured using thin plates to reduce their weight, and completed assemblies typically have numerous spaces. Because cars are not designed to be completely watertight, rain or wash water may leak into the interior spaces of the assembly through gaps or inlets. When water enters a space and is not drained sufficiently, it can fill the space and overflow into unexpected channels, causing severe problems such as part corrosion and electric shock. In our research, based on a decomposition model representation, we have developed a program to graphically simulate all possible flows within the interior spaces between car parts. Our program can simulate the locations of outlets and overflow channels into unexpected regions, and thus help designers verify the effectiveness of their designs before manufacturing, which can therefore reduce the development time and costs. In particular, since the program can simulate overflow when a car in both horizontal and inclined positions, it can prevent possible design errors by engineers who are accustomed to designing cars only in a horizontal orientation. Our developed method can also be applied to aircraft and ship designs.

분해모델과 구멍 메움 알고리즘을 이용한 냉장고 내부 용적의 자동 계산

박래성(Raesung Park),Jianhui Fu,정융호(Yoongho Jung),박민근(Mingeun Park) (사)한국CDE학회 2017 한국CDE학회 논문집 Vol.22 No.1

Internal capacity of a refrigerator is an important indicator for design and purchasing criteria. The components facing the internal space may have holes or gaps between parts. In traditional way, design engineers manually remodeled the parts to fill the holes and the gaps for enclosed boundary of the internal space. Then they calculated internal volume by subtracting the assembly of parts from its enclosing volume. However, filling holes and gaps is not an automated process requiring a plenty of labor and time. In this research, we have developed a voxel-based method to estimate the internal volume of a refrigerator automatically. It starts transforming all components facing the interior space into voxels and fills all holes and gaps automatically by the developed hole-filling algorithm to form a completely closed boundary of the assembly. Then, it identifies the boundary voxels that are facing to the internal voxels with any part of the component. After getting the intersection points between the boundary voxels and the surfaces of components, it generates the boundary surface of triangular facets with the intersection points. Finally, it estimates the internal volume by adding volume of each tetrahedron composed of a triangle of boundary surface and an arbitrary point.

FRP의 원통형 압력 용기제작을 위한 필라멘트 밴드의 감김 시뮬레이션

윤재득(Jaedeuk Yun),Jianhui Fu,정융호(Yoongho Jung) (사)한국CDE학회 2014 한국CDE학회 논문집 Vol.19 No.1

The filament winding method is widely used to manufacture products of fiber reinforced plastics (FRP), such as high pressure vessels, launch tubes and pipes. For reducing winding time, the method of winding by filament band which consists of several filament fibers is used. NC winding machine is used for precise winding and NC path is needed. Before filament winding, users should verify that winding path which presented by a line is appropriate by filament winding simulation. Also, the used length of each filament is different. So, if the peak filament exhausted, it causes to stop manufacturing. In this research, we developed software which visualizes 3D graphic of filament band winding path and simulates winding process on real time. And we proposed algorithm about calculation of each filament usage. We use geodesic equation for generating filament band surface and calculating the usage length of each filament.

Wear Behavior of P/M High Nb Containing γ-TiAl Alloy in Different Environments

Jingwen Qiu,Zhengfan Fu,Bin Liu,Yong Liu,Jianhui Yan,Di Pan,Weidong Zhang 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.6

The wear behavior of Ti–45Al–7Nb–0.3W (at%) alloy prepared by powder metallurgy (P/M) has been investigated using pinon-disk wear tests at the room temperature. The dry sliding wear tests were performed against on a zirconia disk in differentenvironments, viz, argon, hydrogen in nitrogen mixture, air and oxygen. The worn surfaces of Ti–45Al–7Nb–0.3W pins andwear debris were examined by scanning electron microscope, X-ray diffractometer and X-ray photoelectron spectroscopy. It was found that the high Nb containing Ti–45Al–7Nb–0.3W alloy didn’t exhibit better wear resistance in the presence ofoxygen than commercial γ-TiAl (Ti–47Al–2Nb–2Cr–0.2W) alloy. The oxidation on the worn surface and spalling of oxidescaused by the mechanical force during sliding were the main reason for the high wear losses in the air and oxygen. Thezirconia disk underwent a phase transformation caused by the high contact temperature and stress during the sliding tests. The abrasive particles produced in the wear tests largely consisted of the zirconia particles in different environments, exceptin the pure oxygen. The hard zirconia debris was embedded into the friction layer on the worn surfaces of TiAl pins, whichprovided protection against wear to some extent. The main wear mechanisms of Ti–45Al–7Nb–0.3W alloy were abrasivewear of two-body and three-body, some delamination and plastic deformation.

주응력의 방향을 이용한 필라멘트 와인딩 복합재의 섬유 궤적 생성

윤재득(Jaedeuk Yun),정융호(Yoongho Jung),푸쟌훼이(Jianhui Fu) (사)한국CDE학회 2014 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2014 No.2

필라멘트 와인딩은 유리나 탄소 섬유를 맨드릴에 감아서 성형하는 공법으로 고압 밀폐 용기나 각종 파이프 등을 제작할 때 사용된다. 필라멘트 와인딩 궤적을 생성할 때는 반드시 구조물에 가해지는 하중의 방향을 고려해서 감겨지는 섬유의 방향을 결정해야 강도 높은 복합재 구조물을 제작 할 수 있다. 본 논문에서는 벡터장에 접하는 곡선을 의미하는 스트림라인을 사용하여 섬유 궤적을 생성하는 방법을 제시하고자 한다. 제안한 방법을 사용하면 구조해석을 통해 생성된 주응력 방향과 정확히 일치하는 섬유의 궤적을 생성할 수가 있다. 또한, 와인딩을 수행할 때 미끄러짐과 같은 현상이 발생하지 않는 섬유 궤적을 생성하는 방법을 제시하였다. 본 연구에서 제안한 방법을 사용하여 동일한 맨드릴 형상에 대해 다양한 하중조건에서 섬유 궤적을 생성하였으며, 그 결과 각각의 하중 조건에 대하여 최적의 섬유 궤적을 생성하였다. 제안한 방법은 삼각면으로 근사화한 모델인 STL 모델을 사용하여 섬유 궤적을 생성하기 때문에 복잡한 형상에도 적용이 가능하다.

Mechanical performance of sand-lightweight concrete-filled steel tube stub column under axial compression

Xianggang Zhang,Dapeng Deng,Xinyan Lin,Jianhui Yang,Lei Fu 국제구조공학회 2019 Structural Engineering and Mechanics, An Int'l Jou Vol.69 No.6

In order to study the axial compression performance of sand-lightweight concrete-filled steel tube (SLCFST) stub columns, three circular SLCFST (C-SLCFST) stub column specimens and three SLCFST square (S-SLCFST) stub column specimens were fabricated and static monotonic axial compression performance testing was carried out, using the volume ratio between river sand and ceramic sand in sand-lightweight concrete (SLC) as a varying parameter. The stress process and failure mode of the specimens were observed, stress-strain curves were obtained and analysed for the specimens, and the ultimate bearing capacity of SLCFST stub column specimens was calculated based on unified strength theory, limit equilibrium theory and superposition theory. The results show that the outer steel tubes of SLCFST stub columns buckled outward, core SLC was crushed, and the damage to the upper parts of the S-SLCFST stub columns was more serious than for C-SLCFST stub columns. Three stages can be identified in the stress-strain curves of SLCFST stub columns: an elastic stage, an elastic-plastic stage and a plastic stage. It is suggested that AIJ-1997, CECS 159:2004 or AIJ-1997, based on superposition theory, can be used to design the ultimate bearing capacity under axial compression for C-SLCFST and S-SLCFST stub columns; for varying replacement ratios of natural river sand, the calculated stress-strain curves for SLCFST stub columns under axial compression show good fitting to the test measure curves.

Study on Effects of Blending Fiber Type and Ratio on Antibacterial Properties of Chitosan Blended Yarns and Fabrics

Xiao Tian,Tszyin Poon,Yiyi Yang,Hong Hu,Jimin Fu,Jianhui Li,Ben Niu 한국섬유공학회 2022 Fibers and polymers Vol.23 No.9

Chitosan fiber possesses inherent advantages, such as excellent biocompatibility, nontoxicity as well asantibacterial property. However, there is no systematic study on the chitosan fiber blending effect with other fibers, and onthat basis, there is no suitable fiber blending technology for yarn and fabric production, which results in the incorrectproportion of chitosan fiber blended with other fiber type and thus lowers the fabric functionality as well as increases thematerial cost. In this study, thirteen chitosan blended yarns were designed and developed. Blending yarn structure wasexamined and the effects of blending fiber type and ratio on the antibacterial and physical property were firstly investigated. The experimental results show that the inhibition rate rises with the increase of the chitosan blending ratio. The polyester/cotton/chitosan and tencel/chitosan yarns have a better inhibition rate of Staphylococcus than that of the cotton/chitosan yarn,indicating that the blending fiber type has an impact on antibacterial properties. Moreover, various chitosan blended knittedfabrics were produced by using the chitosan blended yarns developed and their antibacterial, physical properties and comfortas well as anti-mite activity were evaluated. The results illustrate that the knitted fabrics with a small amount of chitosanfibers exhibit excellent antibacterial properties and desirable comfort. Furthermore, the chitosan blended fabrics present theanti-mites effect. This work would contribute to lowering the material cost of functional yarns and promoting thedevelopment of antibacterial textiles.