Parametric Surface Defined on Parallelogrammic Domain and its Properties

FAN Shuqian,ZOU Jinsong,SHI Mingquan (사)한국CDE학회 2013 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8

As essential components of many mechanical systems, tooth geometrical properties of spiral bevel gears greatly influence on the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show unique advantage in transmission due to their constant spiral angle property. However, mathematical model suitable for accurate digital modeling, differential geometrical characteristics and related contact analysis methods of tooth surface have not been deeply investigated, since such gears are not convenient to traditional cutting manufacture in gear industry. An accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry. Actually, the tooth surface is a parametric surface defined on parallelogrammic domain. Then, an equivalence proof of the tooth surface geometry is given in order to greatly simplify the mathematical model. As major factors affecting lubrication, surface fatigue, contact stress, wear and manufacturability of gear teeth, differential geometrical characteristics of the tooth surface is summarized employing classical fundamental forms. By using mentioned geometrical properties, manufacturability and its limitation of logarithmic spiral bevel gears is analyzed using precision forging and multi-axis freeform milling, instead of classical cradle-type machine tools based milling or hobbing. Geometry and manufacturability analysis result shows that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multi-axis freeform milling should be further solved.

Parametric surface and properties defined on parallelogrammic domain

Fan, Shuqian,Zou, Jinsong,Shi, Mingquan Society for Computational Design and Engineering 2014 Journal of computational design and engineering Vol.1 No.1

Similar to the essential components of many mechanical systems, the geometrical properties of the teeth of spiral bevel gears greatly influence the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show a unique advantage in transmission due to their constant spiral angle property. However, a mathematical model suitable for accurate digital modeling, differential geometrical characteristics, and related contact analysis methods for tooth surfaces have not been deeply investigated, since such gears are not convenient in traditional cutting manufacturing in the gear industry. Accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed in this study, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry; actually, the tooth surface is a parametric surface defined on a parallelogrammic domain. Equivalence proof of the tooth surface geometry is then given in order to greatly simplify the mathematical model. As major factors affecting the lubrication, surface fatigue, contact stress, wear, and manufacturability of gear teeth, the differential geometrical characteristics of the tooth surface are summarized using classical fundamental forms. By using the geometrical properties mentioned, manufacturability (and its limitation in logarithmic spiral bevel gears) is analyzed using precision forging and multiaxis freeform milling, rather than classical cradle-type machine tool based milling or hobbing. Geometry and manufacturability analysis results show that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multiaxis freeform milling also need to be solved in a further study.

Effects of Selenizing Modification on Characteristics and Antioxidant Activities of Inonotus obliquus Polysaccharide

Yang Hu,Shanyi Shi,Lu Lu,Chunying Teng,Sumei Yu,Xin Wang,Min Yu,Jinsong Liang,Juanjuan Qu 한국고분자학회 2017 Macromolecular Research Vol.25 No.3

Excessive reactive oxygen species is implicated in the etiology and pathology of many acute and chronic diseases. Selenium acts as an antioxidant and stimulates the creation of more antioxidants. Selenizing modification polysaccharides potentiate the physiological and pharmacological activities of selenium and polysaccharide. In this study, Inonotus obliquus polysaccharide (IOP) extracted from cultured mycelia was modified into Se-IOP by HNO3- Na2SeO3 method. The characteristics and antioxidant activity of IOP and Se-IOP were comparatively investigated. The result showed that polysaccharide content of purified IOP was 98.9%. The selenium content of Se-IOP was 0.71 mg/g. Both IOP and Se-IOP were homogeneous polysaccharides with a molecular weight of 37.354 and 28.071 kDa, respectively depicted in high performance gel permeation chromatogram (HPGPC). Moreover, both IOP and Se- IOP were composed of Man, Glu, and Gal with a molar ratio of 7.7:32.6:23.3 and 8.3:32.1:22.7, respectively determined by high performance liquid chromatography (HPLC). The characteristic absorption peak of O-Se-O, Se=O and C-O-Se appeared at 1026.75, 772.82, and 652.29 cm-1 respectively in FT-IR spectrum of Se-IOP indicating the success of selenylation. NMR spectrum further confirmed the anomeric carbon signals and chemical shifts in IOP and Se-IOP. These variations induced by selenylation may lead to a higher antioxidant activity of Se-IOP on scavenging hydroxyl, 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and superoxide radical than that of IOP. Furthermore, Se- IOP treatment could also reduce oxidant damage by decreasing the level of malondialdehyde (MDA) and increasing the activities of superoxidedismutase (SOD) and GSH-Px in mice.

Expression, Purification, and Bioactivity of (GLP-1A2G)2-HSA Analogs in Pichia pastoris GS115

Wenfang Dou,Junshang Feng,Xiaomei Zhang,Hongyu Xu,Jinsong Shi,Zhenghong Xu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.6

We developed (GLP-1A2G)2-HSA (GGH) analogsthat are resistant to degradation and also show high serumglucose-reducing activity in vivo. Five analogs with Nterminalextensions were designed based on the proteinGGH. Next, we constructed recombinant plasmids capableof expressing the five analogs in methylotrophic yeastPichia pastoris GS115. Expression reached 150 mg/L in asmall-scale incubation. Fusion proteins were successfullypurified from the supernatant using ultrafiltration concentration,affinity absorption chromatography, hydrophobicchromatography, ion exchange chromatography and gelfiltration. A single band was observed on SDS-PAGE andthe purity was 97%. Activity test results suggested thatboth A-GGH and G-GGH showed better activity in vitroand that their cAMP levels were significantly increased by10-fold compared to GGH without N-terminal extension. Additionally, A-GGH efficiently enhanced the glucoseloweringeffect, which was maintained after the administrationfor 24 h. A-GGH is a potential drug for treating type 2diabetes.

Improvement of the Steroid Dihydroxylation Efficiency from Dehydroepiandrosterone Using a Substrate Pre-induction Biotransformation Process

Hui Li,Zhenzhen Fu,Heng Li,Wenfang Dou,Jinsong Shi,Zhenghong Xu 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.3

This study investigated the effects of hydroxylase cyptochrome P450 inducers on the efficiency of the biotransformation of dehydroepiandrosterone (DHEA) to 3β, 7α, 15α-trihydroxy-5-androsten-17-one (7α,15α-diOHDHEA)by Colletotrichum lini ST-1. Special attention was given to the substrate DHEA being the best inducer and the fact that it could improve the yield of 7α, 15α-diOHDHEA. Based on the effects of the DHEA pre-induction phases and additional concentrations on 7α, 15α-diOHDHEA production, a substrate pre-induction process was established as follows: 2 g/L DHEA was added for the first time after 12 h of inoculation, followed by the second addition of 6 g/L DHEA after 12 h later. The results showed that this substrate pre-induction process improved the content of cytochrome P450 and that the 7α, 15α-diOH-DHEA yield reached 90.1%, which was 26.9%higher than that obtained in the original process.