Microstructure and Abrasive Wear Properties of Fe-Cr-C Hardfacing Alloy Cladding Manufactured by Gas Tungsten Arc Welding (GTAW)

Jie-Hao Chen,Chih-Chun Hsieh,Pei-Shing Hua,Chia-Ming Chang,Chi-Ming Lin,Paxon Ti-Yuan Wu,Weite Wu 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.1

A series of Fe-Cr-C hardfacing alloys is deposited by gas tungsten arc welding and subjected to abrasive wear testing. Pure Fe with various amounts of CrC (Cr:C=4:1) powders are mixed as the fillers and used to deposit hardfacing alloys on low carbon steel. Depending on the various CrC additions to the alloy fillers,the claddings mainly contain hypoeutectic, near eutectic, or hypereutectic microstructures of austenite γ-Fe phase and (Cr,Fe)7C3 carbides on hardfacing alloys, respectively. When 30% CrC is added to the filler, the finest microstructure is achieved, which corresponds to the γ-Fe+(Cr,Fe)7C3 eutectic structure. With the addition of 35% and 40% CrC to the fillers, the results show that the cladding consists of the massive primary (Cr,Fe)7C3 as the reinforcing phase and interdendritic Fe+(Cr,Fe)7C3 eutectics as the matrix. The (Cr,Fe)7C3 carbide-reinforced claddings have high hardness and excellent wear resistance under abrasive wear test conditions. Concerning the abrasive wear feature observable on the worn surface, the formation and fraction of massive primary (Cr,Fe)7C3 carbides predominates the wear resistance of hardfacing alloys. Abrasive particles result in continuous plastic grooves when the cladding has primary γ-Fe phase in a hypoeutectic structure.

Accurate harmonic analysis of dual‑frequency inverter considering dead‑time effect

Jie Wu,Zhiliang Yang,Wenlei Wang,Yafei Chen,Zhenjun Wu,Jitao Zhang,Jeng-Shyang Pan,Vaclav Snasel 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.9

Wireless power transfer (WPT) systems or simultaneous wireless information and power transfer (SWIPT) systems support multiple charging frequency standards and usually transmit two or more frequencies simultaneously. Multi-frequency sinusoidal pulse width modulation (MF-SPWM) technology can output multiple sine wave frequencies at the same time with only one inverter, which effectively reduces the system size and improves compatibility. However, MF-SPWM and dead-time make the MF-inverter highly nonlinearized, with significant effects on the desired frequencies and the total harmonic distortion (THD) of the multi-frequency output. In this paper, a double Fourier series-based method of harmonic analysis for the dual-frequency inverter (DF-inverter) is proposed, which can accurately calculate the magnitude of each of the harmonics in the output of the DF-inverter taking into account the influence of dead-time. The calculation methods of the minimum pulse width and voltage THD of the DF-inverter are provided. An analysis shows that when the dead-time is less than the minimum pulse width, its influence is negligible. Meanwhile, when the dead-time is slightly larger than the minimum pulse width, there is a trade-off between the desired frequency component and the THD. Experimental results are given and they are consistent with the analytical results of the proposed method, and the error is within 2%.

Ginsenoside Rg3 in combination with artesunate overcomes sorafenib resistance in hepatoma cell and mouse models

Ying-Jie Chen,Jia-Ying Wu,Yu-Yi Deng,Ying Wu,Xiao-Qi Wang,Amy Sze-man Li,Lut Yi Wong,Xiuqiong Fu,Zhi-Ling Yu,Chun Liang 고려인삼학회 2022 Journal of Ginseng Research Vol.46 No.3

Sorafenib is effective in treating hepatoma, but most patients develop resistance to it. STAT3signaling has been implicated in sorafenib resistance. Artesunate (ART) and 20(R)-ginsenoside Rg3 (Rg3)have anti-hepatoma effects and can inhibit STAT3 signaling in cancer cells. This study aimed to evaluatethe effects of Rg3 in combination with ART (Rg3-plus-ART) in overcoming sorafenib resistance, and toexamine the involvement of STAT3 signaling in these effects. Methods: Sorafenib-resistant HepG2 cells (HepG2-SR) were used to evaluate the in vitro anti-hepatomaeffects of Rg3-plus-ART. A HepG2-SR hepatoma-bearing BALB/c-nu/nu mouse model was used to assessthe in vivo anti-hepatoma effects of Rg3-plus-ART. CCK-8 assays and Annexin V-FITC/PI double stainingwere used to examine cell proliferation and apoptosis, respectively. Immunoblotting was employed toexamine protein levels. ROS generation was examined by measuring DCF-DA fluorescence. Results: Rg3-plus-ART synergistically reduced viability of, and evoked apoptosis in HepG2-SR cells, andsuppressed HepG2-SR tumor growth in mice. Mechanistic studies revealed that Rg3-plus-ART inhibitedactivation/phosphorylation of Src and STAT3 in HepG2-SR cultures and tumors. The combination alsodecreased the STAT3 nuclear level and induced ROS production in HepG2-SR cultures. Furthermore, overactivation of STAT3 or removal of ROS diminished the anti-proliferative effects of Rg3-plus-ART, andremoval of ROS diminished Rg3-plus-ART's inhibitory effects on STAT3 activation in HepG2-SR cells. Conclusions: Rg3-plus-ART overcomes sorafenib resistance in experimental models, and inhibition of Src/STAT3 signaling and modulation of ROS/STAT3 signaling contribute to the underlying mechanisms. Thisstudy provides a pharmacological basis for developing Rg3-plus-ART into a novel modality for treatingsorafenib-resistant hepatoma.

Approaches of Collaborative Cloud Process Service : Constructing Service-Oriented Architecture

Chen Wang,Wu Zhao,Jie Wang,Ling Chen 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.11

Process service is an important segment of cloud manufacturing ecosystem, in which virtualized process resources are furnished as consumable services. In this paper, a service-oriented approach cloud process service is proposed to achieve a collaborative processing environment for distributed participants. In order to implement the cloud process service, it’s important to identify the existing process resources and capabilities, then virtualize them as processing services. In the first place, basic features of process service are summarized, and a standardized business model and process knowledge base are built to describe concept, cloud service and relevant features. Besides, a seven layer structure of cloud platform is proposed with a virtualization methodology to describe process service, source provider and process service requests. In the end, a case is presented to demonstrate the ability of integrating cloud process services.

An improved interval analysis method for uncertain structures

Wu, Jie,Zhao, You Qun,Chen, Su Huan Techno-Press 2005 Structural Engineering and Mechanics, An Int'l Jou Vol.20 No.6

Based on the improved first order Taylor interval expansion, a new interval analysis method for the static or dynamic response of the structures with interval parameters is presented. In the improved first order Taylor interval expansion, the first order derivative terms of the function are also considered to be intervals. Combining the improved first order Taylor series expansion and the interval extension of function, the new interval analysis method is derived. The present method is implemented for a continuous beam and a frame structure. The numerical results show that the method is more accurate than the one based on the conventional first order Taylor expansion.

A Novel Xylanase from Streptomyces sp. FA1: Purification, Characterization, Identification, and Heterologous Expression

Jie He,Lingqia Su,Xiaojun Sun,Jiajia Fu,Jian Chen,Jing Wu 한국생물공학회 2014 Biotechnology and Bioprocess Engineering Vol.19 No.1

A xylanase (XynA) was purified from the culturemedium of Streptomyces sp. FA1, which was previouslyisolated from a bamboo retting system. XynA had amolecular mass of 43 kDa, displayed maximal activity atpH 5.5, retained 41% of its maximal activity at pH 11.0,and was stable over a wide pH range (3.0 ~ 11.0). PurifiedXynA was subjected to peptide mass fingerprinting, whichled to the cloning of the xynA gene. The xynA gene, whichencodes a mature protein of 436 amino acids, washeterologously expressed in E. coli BL21(DE3). The activityin the culture medium could reach 213.5 U/mL, which was11.2-fold higher than that produced by Streptomyces sp. FA1. BLAST searching revealed that full-length XynAshares less than 90% identity with most of its homologues,whereas amino acids 48-436 of the enzyme share 97%identity with an open reading frame encoding a putativefull-length mature xylanase from Streptomyces tendae. Thetruncated xynA gene, xynA48-436, was cloned and expressedin E. coli, however, no xylanase activity could be detectedin the culture medium. Based on these results, it is suggestedthat XynA is a new member of glycoside hydrolasesfamily10 with exceptional catalytic efficiency at alkalinepH.

Priority-based Unequal Error Protection Scheme of Data partitioned H.264 video with Hierarchical QAM

( Chen Rui ),( Wu Minghu ),( Yang Jie ),( Rui Xiongli ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.11

In this paper, we propose a priority-based unequal error protection scheme of data partitioned H.264/AVC video with hierarchical quadrature amplitude modulation. In order to map data with higher priority onto the most significant bits of QAM constellation points, a priority sorting method categorizes different data partitions according to the unequal importance factor of encoded video data in one group of pictures by evaluated the average distortion. Then we propose a hierarchical quadrature amplitude modulation arrangement with adaptive constellation distances, which takes into account the unequal importance of encoded video data and the channel status. Simulation results show that the proposed scheme improves the received video quality by about 2 dB in PSNR comparing with the state-of-the-art unequal error protection scheme, and outperforms EEP scheme by up to 5 dB when the average channel SNR is low.

Dissecting the meteorological and genetic factors affecting rice grain quality in Northeast China

Chen Mojun,Li Zhao,Huang Jie,Yan Yongfeng,Wu Tao,Bian Mingdi,Zhou Jinsong,Wang Yongjun,Lyv Yanjie,Hu Guanghui,Jin Yong-Mei,Huang Kai,Guo Liping,Jiang Wenzhu,Du Xinglin 한국유전학회 2021 Genes & Genomics Vol.43 No.8

Background The Northeast Plain of China, which is an important region for the production of high grain quality rice in China. However, the grain quality of the rice produced varies across this region, even for the same cultivar. Objective In order to explore the meteorological factors that have the greatest infuence on quality and the transcriptional level diferences between diferent cultivars and diferent locations at grain flling stage. Methods We grew eight rice cultivars in three locations in Northeast China during two growing seasons (2017 and 2018). We recorded meteorological conditions, including air temperature, air temperature range, and photosynthetically active radiation (PAR) during the grain-flling stage of each cultivar, and analyzed the grain quality of those eight cultivars. Results Across all eight cultivars, meteorological factors had a stronger efect on eating quality than genotype, while genotype had a stronger efect on milling quality. Of the three environmental factors assessed, PAR was signifcantly correlated with the most grain quality traits. Using RNA-sequencing analysis, we identifed 573 environment-specifc DEGs (Diferentially Expressed Genes), and 119 genotype-specifc DEGs; 11 DEGs were responsive to genotype×environment interactions. These DEGs were involved in many key metabolic processes. Conclusion Our results indicated that interactions among environmental factors, especially PAR, afected rice quality in Northeast China. Further analyses of the DEGs identifed herein may provide useful information for future breeding programs aiming to develop high grain quality rice varieties suitable for cultivation across Northeast China.

Observed Quasi-steady Kinetics of Yeast Cell Growth and Ethanol Formation under Very High Gravity Fermentation Condition

Chen Li-Jie,Xu Ya-Li,Bai Feng-Wu,Anderson William A.,Murray Moo-Young The Korean Society for Biotechnology and Bioengine 2005 Biotechnology and Bioprocess Engineering Vol.10 No.2

Using a general Saccharomyces cerevisiae as a model strain, continuous ethanol fermentation was carried out in a stirred tank bioreactor with a working volume of 1,500 mL. Three different gravity media containing glucose of 120, 200 and 280 g/L, respectively, supplemented with 5 g/L yeast extract and 3 g/L peptone, were fed into the fermentor at different dilution rates. Although complete steady states developed for low gravity medium containing 120 g/L glucose, quasi-steady states and oscillations of the fermented parameters, including residual glucose, ethanol and biomass were observed when high gravity medium containing 200 g/L glucose and very high gravity medium containing 280 g/L glucose were fed at the designated dilution rate of $0.027\;h^{-1}$. The observed quasi-steady states that incorporated these steady states, quasi-steady states and oscillations were proposed as these oscillations were of relatively short periods of time and their averages fluctuated up and down almost symmetrically. The continuous kinetic models that combined both the substrate and product inhibitions were developed and correlated for these observed quasi-steady states.

Clinical Study of Thalidomide Combined with Dexamethasone for the Treatment of Elderly Patients with Newly Diagnosed Multiple Myeloma

Chen, Hai-Fei,Li, Zheng-Yang,Tang, Jie-Qing,Shen, Hong-Shi,Cui, Qing-Ya,Ren, Yong-Ya,Qin, Long-Mei,Jin, Ling-Juan,Zhu, Jing-Jing,Wang, Jing,Ding, Jie,Wang, Ke-Yuan,Yu, Zi-Qiang,Wang, Zhao-Yue,Wu, Tian Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

Objective: To investigate the relationship between the efficacy and safety of different doses of thalidomide (Thal) plus dexamethasone (Dex) as the initial therapy in elderly patients with newly diagnosed multiple myeloma (MM). Methods: Clinical data of 28 elderly patients with newly diagnosed MM who underwent the TD regimen as the initial therapy were analyzed retrospectively. The patients were divided into two groups according to the maximal sustained dose of Thal: lower dose (group A) and higher dose (group B). The overall response rate (ORR), progression free survival (PFS), overall survival (OS), and adverse events (AES) were compared between the two groups. Results: A total of 28 patients were followed up with a median of 18 months. The ORR was 60.1%. The median response time and PFS were 2.0 and 17.0 months, respectively. The mean sustained dose of Thal in group B was significantly higher than group A (292.9 mg v 180.4 mg, P=0.01). There was no significantly difference in ORR (57.1% v 64.3%, P=1.00) and PFS (9.63months v 17.66 months, P=0.73) between groups A and B. During the follow up, only five patients died (<40%) and, therefore, median OS values were not available. It is estimated, however, that the mean survival time in the two groups was 35.6 and 33.4 months (P>0.05), respectively. All of the patients tolerated the treatment well. The incidence of AES in patients with a grading above 3 in group B was significantly higher than in group A (P=0.033). Conclusions: The TD regimen results in a high response rate and manageable AES as the initial therapy in elderly patients with MM. TD should be considered as the front line regimen for the treatment of elderly patients with MM in areas with financial constraints. The clinical response can be achieved at a low dose Thal with minimal toxicity.