Restoring force model for circular RC columns strengthened by pre-stressed CFRP strips

Changdong Zhou,Xilin Lu,Hui Li,Teng Tian 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.4

This paper presents a tri-linear restoring force model based on the test results of 12 circular RC columns strengthened by CFRP strips under low cyclic loading. The pre-stress of CFRP strips and axial load ratio of specimens are considered as the affect parameters of the proposed model. All essential characteristics of the hysteretic behavior of the proposed model, including the hysteretic rules, main performance points, strength degradation, stiffness degradation and confinement effects are explicitly analyzed. The calculated results from the proposed model are in good agreement with the experimental results, which shows that the recommended model can be reliably used for seismic behavior predictions of circular RC columns strengthened by pre-stressed CFRP strips.

INFLUENCE OF RAIL PRESSURE ON A TWO-STAGE TURBOCHARGED HEAVY-DUTY DIESEL ENGINE UNDER TRANSIENT OPERATION

Z. C. LIU,K. B. YU,J. TIAN,Y. Q. HAN,S. L. QI,P. K. TENG 한국자동차공학회 2017 International journal of automotive technology Vol.18 No.1

The demand for continually improving the transient performance of diesel engines requires higher rail pressure and more efficient turbocharger. Before the test, a two-stage turbocharger with a turbine by-pass valve (TBV) had been matched reasonably with the base engine. In order to reduce smoke emission under the typical 5-second transient process of constant speed and increasing torque, the influence of rail pressure on combustion, emissions and performance characteristics was experimentally investigated. The results showed that the two-stage turbocharger was helpful in improving transient performance. Moreover, the full-stage rail pressure (FSRP) strategies (increasing rail pressure during the whole transient process) could reduce smoke emission when the TBV was closed. However, smoke deteriorated once TBV opening got larger. Then the sectional-stage rail pressure (SSRP) strategies (increasing rail pressure from a pre-set load to 100 % load) were presented under small TBV opening to improve in-cylinder thermal condition. Hence, the air-fuel mixing process was improved at medium and large loads. Then the maximum decline of smoke opacity peak was 56.3 %, which happened under 10 % TBV opening. In addition, fuel consumption of FSRP strategies got worse under larger TBV opening. However, this deterioration situation could be effectively restrained by the utilization of SSRP strategies.

EFFECTS OF INJECTION TIMING ON TRANSIENT PERFORMANCE OF A REGULATED TWO-STAGE TURBOCHARGED DIESEL ENGINE WITH TURBINE BYPASS VALVE

Zhong Chang Liu,Xing Yuan,Jing Tian,Yong Qiang Han,Kai Bo Yu,Peng Kun Teng 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.5

The object of this paper is to reduce soot emissions under typical 5s transient conditions of constant speed and increasing torque. And effects of fuel injection timing on combustion and emissions parameters were experimentally and numerically studied in a regulated two-stage turbocharged diesel engine with a turbine bypass valve (TBV). The test results indicated that: the smaller TBV opening could improve deterioration of smoke emissions and BSFC at medium and heavy loads. Afterward, the full-stage injection timing (FSIT) strategies (delaying injection timing during the entire transient process) could reduce soot and NOX emissions simultaneously. However, when TBV opening became larger, smoke emissions and BSFC were deteriorated gradually. Moreover, the sectional-stage injection timing (SSIT) strategies (advancing injection timing from 10 % load to a preset load and delaying injection timing from the preset load to 100 % load) could markedly reduce soot emissions by 75.8 % with TBV opening 20 %; the degradation of fuel consumption could be effectively suppressed. Finally, coupling the SSIT strategies with the TBV control strategies could significantly improve the transient performance.

Separation of arenols from a low-temperature coal tar by liquid-liquid extraction

Hua-Shuai Gao,Zhi-Min Zong,Zheng Yang,Dao-Guang Teng,Xiu-Hua Sun,Li Yan,Xian-Yong Wei,Qing-Jie Guo,Tian-Sheng Zhao,Hong-Cun Bai 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.5

Low-temperature coal tar (LTCT) is a sticky liquid mixture produced mainly from coal pyrolysis, which contains various value-added chemicals (VACs). Liquid-liquid extraction is considered as one of the green and effective ways to explore the organic composition and separate the VACs from LTCT. Herein, petroleum ether, methanol, and carbon disulfide were used to extract arenols from a LTCT. As a result, the relative content and absolute content of arenols extracted from the LTCT are ca. 96.3% and 85.9%, respectively. Among them, p-cresol is predominant, accounting for 22.2%. The isolated contents of arenols are up to 84.6%. Moreover, a kilogram-scale operation was carried out under the same conditions, which offers a potential application in industrial production.

Isolation of a Natural Antioxidant, Dehydrozingerone from Zingiber officinale and Synthesis of lts Analogues for Recognition of Effective Antioxidant and Antityrosinase Agents

Kuo, Ping-Chung,Damu, Amooru G.,Cherng, Ching-Yuh,Jeng, Jye-Fu,Teng, Che-Ming,Lee, E-Jian,Wu, Tian-Shung The Pharmaceutical Society of Korea 2005 Archives of Pharmacal Research Vol.28 No.5

In the present study, the antioxidative and inhibitory activity of Zingiber officinale Rosc. Rhizomes-derived materials (on mushroom tyrosinase) were evaluated. The bioactive co mponents of Z. officinale rhizomes were characterized by spectroscopic analysis as zingerone and dehydrozingerone, which exhibited potent antioxidant and tyrosinase inhibition activities. A series of substituted dehydrozingerones [(E)-4-phenyl-3-buten-2-ones] were prepared in admirable yields by the reaction of appropriate benzaldehydes with acetone and the products were evaluated in terms of variation in the dehydrozingerone structure. The synthetic analogues were examined for their antioxidant and antityrosinase activities to probe the most potent analogue. Compound 26 inhibited Fe$^{2+}$-induced lipid peroxidation in rat brain homogenate with an IC$_{50}$ = 6.3${\pm}$0.4 ${\mu}$M. In the 1,1-diphenyl- 2-picrylhydrazyl (DPPH) radical quencher assay, compounds 2, 7, 17, 26, 28, and 29 showed radical scavenging activity equal to or higher than those of the standard antioxidants, like ${\alpha}$-tocopherol and ascorbic acid. Compound 27 displayed superior inhibition of tyrosinase activity relative to other examined analogues. Compounds 2, 17, and 26 exhibited non-competitive inhibition against oxidation of 3,4- dihydroxyphenylalanine (L-DOPA). From the present study, it was observed that both number and position of hydroxyl groups on aromatic ring and a double bond between C-3 and C-4 played a critical role in exerting the antioxidant and antityrosinase activity.

Association of Matrix Metalloproteinase (MMP)-2 and -9 Expression with Extra-gastrointestinal Stromal Tumor Metastasis

Wang, Chao,Ma, Hong-Xi,Jin, Mei-Shan,Zou, Ya-Bin,Teng, Yong-Liang,Tian, Zhuang,Wang, Hai-Ying,Wang, Yin-Ping,Duan, Xiu-Mei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.10

Matrix metalloproteinase (MMP)-2 and MMP-9 are important proteases involved in invasion and metastasis of various tumors. Extra-gastrointestinal stromal tumors (EGISTs) are rare neoplasms. This study was performed to assess MMP-2 and MMP-9 expression in EGIST tissue samples for association with clinicopathological data from the patients. Twenty-one surgical EGIST tissue specimens were collected for analysis of MMP-2 and MMP-9 expression using immunohistochemistry. MMP-2 and MMP-9 proteins were expressed in all of the epithelial cell types of EGISTs, whereas they were only expressed in 75% of the spindle cell type, although there was no statistically significant difference (p>0.05). Expression of MMP-2 and MMP-9 proteins was associated with tumor size, mitotic rate, tumor necrosis, and distant metastasis (p<0.05). MMP-2 expression was linked with MMP-9 levels (p<0.05). However, there was no correlation between MMP-9 expression and age, sex, primary site, or cell morphology in any of these 21 EGIST patients (p>0.05). Moreover, expression of MMP-2 and MMP-9 proteins increased with the degree of EGIST risk. This study provided evidence of an association of MMP-2 and MMP-9 expression with advanced EGIST behavior.

Age-induced Changes in Ginsenoside Accumulation and Primary Metabolic Characteristics of Panax Ginseng in Transplantation Mode

Wei Yuan,Qing-feng Wang,Wen-han Pei,Si-yu Li,Tian-min Wang,Hui-peng Song,Dan Teng,Ting-guo Kang,Hui Zhang 고려인삼학회 2024 Journal of Ginseng Research Vol.48 No.1

Background: Ginseng (Panax ginseng Mayer) is an important natural medicine. However, a long culture period andchallenging quality control requirements limit its further use. Although artificial cultivation can yield a sustainablemedicinal supply, research on the association between the transplantation and chaining of metabolicnetworks, especially the regulation of ginsenoside biosynthetic pathways, is limited. Methods: Herein, we performed Liquid chromatography tandem mass spectrometry based metabolomic measurementsto evaluate ginsenoside accumulation and categorise differentially abundant metabolites (DAMs). Transcriptome measurements using an Illumina Platform were then conducted to probe the landscape of geneticalterations in ginseng at various ages in transplantation mode. Using pathway data and crosstalk DAMs obtainedby MapMan, we constructed a metabolic profile of transplantation Ginseng. Results: Accumulation of active ingredients was not obvious during the first 4 years (in the field), but followingtransplantation, the ginsenoside content increased significantly from 6 8 years (in the wild). Glycerolipidmetabolism and Glycerophospholipid metabolism were the most significant metabolic pathways, as Lipids andlipid-like molecule affected the yield of ginsenosides. Starch and sucrose were the most active metabolic pathwaysduring transplantation Ginseng growth. Conclusion: This study expands our understanding of metabolic network features and the accumulation of specificcompounds during different growth stages of this perennial herbaceous plant when growing in transplantationmode. The findings provide a basis for selecting the optimal transplanting time.

Isolation of a Natural Antioxidant, Dehydrozingerone from Zingiber officinale and Synthesis of Its Analogues for Recognition of Effective Antioxidant and Antityrosinase Agents

Ping-Chung Kuo,Amooru G. Damu,Ching-Yuh Cherng,Jye-Fu Jeng,Che-Ming Teng,E-Jian Lee,Tian-Shung Wu 대한약학회 2005 Archives of Pharmacal Research Vol.28 No.5

In the present study, the antioxidative and inhibitory activity of Zingiber officinale Rosc. rhizomes- derived materials (on mushroom tyrosinase) were evaluated. The bioactive components of Z. officinale rhizomes were characterized by spectroscopic analysis as zingerone and dehydrozingerone, which exhibited potent antioxidant and tyrosinase inhibition activities. A series of substituted dehydrozingerones [(E)-4-phenyl-3-buten-2-ones] were prepared in admirable yields by the reaction of appropriate benzaldehydes with acetone and the products were evaluated in terms of variation in the dehydrozingerone structure. The synthetic analogues were examined for their antioxidant and antityrosinase activities to probe the most potent analogue. Compound 26 inhibited Fe2+-induced lipid peroxidation in rat brain homogenate with an IC50 = 6.3±0.4 µM. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical quencher assay, compounds 2, 7, 17, 26, 28, and 29 showed radical scavenging activity equal to or higher than those of the standard antioxidants, like α-tocopherol and ascorbic acid. Compound 27 displayed superior inhibition of tyrosinase activity relative to other examined analogues. Compounds 2, 17, and 26 exhibited non-competitive inhibition against oxidation of 3,4- dihydroxyphenylalanine (L-DOPA). From the present study, it was observed that both number and position of hydroxyl groups on aromatic ring and a double bond between C-3 and C-4 played a critical role in exerting the antioxidant and antityrosinase activity.

Hierarchical porous ECM scaffolds incorporating GDF-5 fabricated by cryogenic 3D printing to promote articular cartilage regeneration

Wu Jiang,Fu Liwei,Yan Zineng,Yang Yu,Yin Han,Li Pinxue,Yuan Xun,Ding Zhengang,Kang Teng,Tian Zhuang,Liao Zhiyao,Tian Guangzhao,Ning Chao,Li Yuguo,Sui Xiang,Chen Mingxue,Liu Shuyun,Guo Quanyi 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

In recent years, there has been significant research progress on in situ articular cartilage (AC) tissue engineering with endogenous stem cells, which uses biological materials or bioactive factors to improve the regeneration microenvironment and recruit more endogenous stem cells from the joint cavity to the defect area to promote cartilage regeneration.In this study, we used ECM alone as a bioink in low-temperature deposition manufacturing (LDM) 3D printing and then successfully fabricated a hierarchical porous ECM scaffold incorporating GDF-5.Comparative in vitro experiments showed that the 7% ECM scaffolds had the best biocompatibility. After the addition of GDF-5 protein, the ECM scaffolds significantly improved bone marrow mesenchymal stem cell (BMSC) migration and chondrogenic differentiation. Most importantly, the in vivo results showed that the ECM/GDF-5 scaffold significantly enhanced in situ cartilage repair.In conclusion, this study reports the construction of a new scaffold based on the concept of in situ regeneration, and we believe that our findings will provide a new treatment strategy for AC defect repair.