Experimental Study on Mechanical Properties of Ultrasonic Nanocrystal Surface Modification

Shanshan He(허산산),QINGYE JIN(진칭예),S. J. Lee(이승진),S. H. Park(박상후) 한국기계가공학회 2020 한국기계가공학회 춘추계학술대회 논문집 Vol.2020 No.11

A chord error conforming tool path B-spline fitting method for NC machining based on energy minimization and LSPIA

He, Shanshan,Ou, Daojiang,Yan, Changya,Lee, Chen-Han Society for Computational Design and Engineering 2015 Journal of computational design and engineering Vol.2 No.4

Piecewise linear (G01-based) tool paths generated by CAM systems lack $G_1$ and $G_2$ continuity. The discontinuity causes vibration and unnecessary hesitation during machining. To ensure efficient high-speed machining, a method to improve the continuity of the tool paths is required, such as B-spline fitting that approximates G01 paths with B-spline curves. Conventional B-spline fitting approaches cannot be directly used for tool path B-spline fitting, because they have shortages such as numerical instability, lack of chord error constraint, and lack of assurance of a usable result. Progressive and Iterative Approximation for Least Squares (LSPIA) is an efficient method for data fitting that solves the numerical instability problem. However, it does not consider chord errors and needs more work to ensure ironclad results for commercial applications. In this paper, we use LSPIA method incorporating Energy term (ELSPIA) to avoid the numerical instability, and lower chord errors by using stretching energy term. We implement several algorithm improvements, including (1) an improved technique for initial control point determination over Dominant Point Method, (2) an algorithm that updates foot point parameters as needed, (3) analysis of the degrees of freedom of control points to insert new control points only when needed, (4) chord error refinement using a similar ELSPIA method with the above enhancements. The proposed approach can generate a shape-preserving B-spline curve. Experiments with data analysis and machining tests are presented for verification of quality and efficiency. Comparisons with other known solutions are included to evaluate the worthiness of the proposed solution.

Experimental study on mechanical properties of additive manufactured 316L under high-pressure hydrogen ambient condition

Shanshan He(허산산),Sanghu Park(박상후),Seongjae Son(손성재) 한국기계가공학회 2020 한국기계가공학회 춘추계학술대회 논문집 Vol.2020 No.6

Parameter Optimization of Cermet Coating (WC10%–Ni60AA) on 316L Stainless Steel via Laser-directed Energy Deposition

Shanshan He(허산산),Sanghu Park(박상후),Do-sik Shim(심도식) 한국기계가공학회 2023 한국기계가공학회지 Vol.22 No.8

Evaluation of thermal comfort in air-conditioned rooms based on structure/control-related parameters and data-mining method

Zhao Shunan,He Lin,Wu Xin,Xu Guowen,Xie Junlong,Cai Shanshan 대한설비공학회 2023 International Journal of Air-Conditioning and Refr Vol.31 No.1

Evaluating the thermal environment and thermal comfort in an air-conditioned room is an essential for estimating the performance of air-conditioning systems. However, multiple component structures and control-related parameters often lead to a long test cycle and large number of tests, significantly affecting the testing efficiency and speed. To address these problems, in this study, a data-mining method was proposed to predict and evaluate the thermal environment of an air-conditioned room. Owing to the limited amount of experimental data, the sample data were expanded by the simulation data of a collaborative platform between the air-conditioning system and air-conditioned room. Data-mining models, including the support vector regression (SVR), backpropagation (BP), and multiple linear regression (MLR) models, were developed and achieved good accuracy in evaluating the thermal environment by considering air-conditioning systems with various structures and control parameters. In the multiple-input single-output evaluation method, the prediction accuracy of the SVR model was higher than those of the BP and MLR models with respect to the vertical air temperature difference, temperature uniformity, temperature drop rate, and draft rate, while the result was the opposite in terms of the predicted mean vote indices. In the multiple-input multiple-output evaluation method, there was a decline in prediction accuracy and an increase in efficiency prediction compared with multiple-input single-output evaluation.

Coupling vibration response analysis of wind-train-bridge system considering the train-induced wind effect

Yujing Wang,Weiwei Guo,He Xia,Shanshan Wang,Man Xu 한국풍공학회 2021 Wind and Structures, An International Journal (WAS Vol.33 No.3

Considering the wind loads and track irregularity as external excitation, the wind-train-bridge dynamic analysis model considering the longitudinal freedom of train is established in the present study. In the model, the wind load of trainbridge system under the train-induced wind field and the combined wind field is obtained by employing Computational Fluid Dynamics (CFD) method. With the CRH2 high-speed train and a 10-span simply-supported box girder bridge as an example, the whole history of the train running on the bridge under the combined effect of train-induced wind and crosswind is simulated to analyze the dynamic response of the train-bridge system. In addition, the operational safety indicators of the train are evaluated. According to the obtained results, the dynamic response of vehicles and bridges increases with the train speed without the consideration of the crosswind. In the combined wind field, the train-induced wind exerts a greater impact on the dynamic response of the vehicle, but has a less influence on that of the bridge simultaneously. Moreover, the influence of wind velocity is greater than that of train speed. When the wind-train-bridge dynamic response analysis is carried out based on traditional methods, the calculated wind load of the train-bridge system is too high, making the calculated responses too large to be consistent with actual values.

Establishment of Full Genomic Length Resistance-Associated Variant Genotype 2 Hepatitis C Viruses and Applications for Future Therapeutic Strategies

( Hyung Joon Yim ),( Billy Lin ),( Shanshan He ),( Zongyi Hu ),( T. Jake Liang ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: Several directly acting antiviral agents (DAA) were currently approvedfor the treatment of chronic hepatitis C (CHC). AlthoughDAA therapies are associated with better tolerability and improvedresponse rates, occurrence of drug resistance has been the drawback.The aim of the present study is to develop full-length resistance associatedvariants (RAV) HCV culture systems to evaluate the efficacyand the cross resistance of current antiviral drugs for future therapeuticstrategies.Methods: Resistance associated substitutions on NS3 (A156T, D168V),NS5A (L31V, Y93H, L31V+Y93H), and NS5B (S282T) domains weregenerated by site directed mutagenesis and cloned into genotype2a J6/JFH1 HCV plasmid with or without luciferase gene. After In vitro RNA transcription, RNAs of RAV were transfected into Huh 7.5.1cells. HCVcc in the supernatants were collected and used for thereinfection and treatment experiment to confirm drug susceptibility.We performed HCV core staining and Renilla luciferease assays toassess treatment response to multiple DAAs and other antiviral drugswith different mechanism of action after transfection or infectionof RAVs.Results: DAAs in the same classes shared cross resistance to correspondingRAVs: boceprevir, telaprevir, simeprevir, and asunaprevirto NS3 RAVs; daclatasvir and ledipasvir to NS5A RAVs; sofosbuvirto NS5B RAV. However, DAAs of the other classes effectively suppressedRAVs as well as wild type. All the RAVs were sensitive todrugs with different action of mechanism including interferon alfa,ribavirin, cyclosporine (cyclophilin inhibitor) or chlorcyclizine (entry inhibitors).Conclusions: We developed full-length RAV HCV culture systemsbased on genotype 2a strain. This system will be useful to assessantiviral response of drugs with different action of mechanisms.Combination of different classes of DAA or new drugs with differentaction mechanisms (e.g. cyclophilin inhibitor or entry inhibitors) shouldbe a future therapeutic strategy for overcoming drug resistance inthe treatment of CHC.

Preliminary study of genome-wide association identified novel susceptibility genes for thyroid-related hormones in Chinese population

Huang Liang,Bai Fenghua,Zhang Yutian,Zhang Shanshan,Jin Tianbo,Wei Xingwei,Zhou Xiaoli,Lin Mei,Xie Yufei,He Chanyi,Lin Qi,Xie Tian,Ding Yipeng 한국유전학회 2022 Genes & Genomics Vol.44 No.8

Background: Thyroid hormones are critical regulators of metabolism, development and growth in mammals. However, the genetic association of thyroid-related hormones in the Chinese Han population is not fully understood. Objective: We aimed to identify the genetic loci associated with circulating thyroid-related hormones concentrations in the healthy Chinese Han population. Methods: Genotyping was performed in 124 individuals using Applied Biosystems™ Axiom™ PMDA, and 796,288 single nucleotide polymorphisms (SNPs) were available for the GWAS analysis. For replication, eleven SNPs were selected as candidate loci for genotyping by Agena MassARRAY platform in additional samples (313 subjects). The values of p < 5 × 10- 6 suggest a suggestively significant genome-wide association with circulating thyroid-related hormones concentrations. Results: We identified that rs11178277 (PTPRB, p = 4.88 × 10- 07) and rs7320337 (LMO7DN-KCTD12, p = 1.22 × 10- 06) were associated with serum FT3 level. Three SNPs (rs4850041 in LOC105373394-LINC01249: p = 3.55 × 10- 06, rs6867291 in LINC02208: p = 2.40 × 10- 06 and rs79508321 in WWOX: p = 3.35 × 10- 06) were related to circulating T3 level. Rs12474167 (LOC105373394-LINC01249, p = 1.65 × 10- 06) and rs1864553 (IWS1, p = 2.00 × 10- 06) were associated with circulating T4 concentration. The association with TGA concentration was for rs17163542 in DISP1 (p = 3.46 × 10- 06) and rs12601151 in NOG-C17orf67 (p = 2.72 × 10- 07). Two genome-level significant SNPs (rs2114707 in LINC01314, p = 1.69 × 10- 06 and rs12601151, p = 1.41 × 10- 07) associated with serum TMA concentration were identified. Moreover, rs6083269 (CST1-CST2, p = 3.36 × 10- 06) was a significant locus for circulating TSH level. In replication, rs12601151 in NOG-C17orf67 was still associated with serum TGA level (p = 0.012). Conclusions: The GWAS reported 11 new suggestively significant loci associated with circulating thyroid-related hormones levels among the Chinese Han population. These findings represented suggestively biological candidates for circulating thyroid-related hormones levels and provided new insights into the mechanisms of regulating serum TGA concentration.

An Improved B-Spline Fitting Method with Arc-Length Parameterization, G2-Continuous Blending, and Quality Refinement

Kang Min,Yanyan Sun,Chen-Han Lee,Pengcheng Hu,Shanshan He 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.11

In computer numerical control machining, tool paths are typically represented with piecewise linear segments (GO1s), which lack G1 and G2 continuity and cause fluctuation of feed rate and acceleration. To improve the continuity of tool paths, some method, e.g., B-spline tool path fitting, is preferred. However, none of the currently B-spline fitting method satisfies all tool-path fitting requirements of arc-length parameterization, G2 continuity and smoothness across the whole path. The aim of this research is to derive an industrial-strength method for B-spline tool path fitting, satisfying all of the named requirements. The improvements cover the arc-length based parameterization, G2 continuity as well as numerically measure to improve the quality of B-spline tool paths. To achieve arc-length parameterization, a preliminary fitting is added to evaluate arc-length and guide the parameterization (i.e., knot vector assignment); for joint G2-continuity, a five-control-point B-spline which satisfies chord error and shape-preserving constraints is constructed to blend adjacent B-splines; and a method based on the Hausdorff distance between the fitted B-splines and the original polylines is used to evaluate the fitting quality, and an additional refinement procedure is employed when the evaluation finds any disqualification. Simulation and experiment results prove that the proposed methods are effective.

Modified Renshen Wumei Decoction Alleviates Intestinal Barrier Destruction in Rats with Diarrhea

( Zhiwei Guan ),( Qiong Zhao ),( Qinwan Huang ),( Zhonghe Zhao ),( Hongyun Zhou ),( Yuanyuan He ),( Shanshan Li ),( Shifang Wan ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.9

Modified Renshen Wumei decoction (MRWD), a famous traditional Chinese medicine, is widely used for treating persistent diarrhea. However, as the mechanism by which MRWD regulates diarrhea remains unknown, we examined the protective effects of MRWD on intestinal barrier integrity in a diarrhea model. In total, 48 male rats were randomly distributed to four treatment groups: the blank group (CK group), model group (MC group), Medilac-Vita group (MV group) and Chinese herb group (MRWD group). After a 21-day experiment, serum and colon samples were assessed. The diarrhea index, pathological examination findings and change in D-lactate and diamine oxidase (DAO) contents illustrated that the induction of diarrhea caused intestinal injury, which was ameliorated by MV and MRWD infusion. Metabolomics analysis identified several metabolites in the serum. Some critical metabolites, such as phosphoric acid, taurine, cortisone, leukotriene B4 and calcitriol, were found to be significantly elevated by MRWD infusion. Importantly, these differences correlated with mineral absorption and metabolism and peroxisome proliferator-activated receptor (PPAR) pathways. Moreover, it significantly increased the expression levels of TLR4, MyD88 and p-NF-κB p65 proteins and the contents of IL-1 and TNF-α, while the expression levels of occludin, claudin-1 and ZO-1 proteins decreased. These deleterious effects were significantly alleviated by MV and MRWD infusion. Our findings indicate that MRWD infusion helps alleviate diarrhea, possibly by maintaining electrolyte homeostasis, improving the intestinal barrier integrity, and inhibiting the TLR4/NF-κB axis.