Plastic / Superplastic Forming : ISOTHERMAL DEFORMATION AT HIGH STRAIN RATE AND MIDDLE TEMPERATURE OF A Ti - 8Co - 5Al ALLOY

Ge Honglin,Zhang Jin Xu,Xu Jiaolong 대한금속재료학회 ( 구 대한금속학회 ) 1995 Advanced Material and Processing Vol.1 No.-

CUBIC B-SPLINE FINITE ELEMENT METHOD FOR THE ROSENAU-BURGERS EQUATION

Ge-Xing Xu,Chun-Hua Li,GUANG-RI PIAO 영남수학회 2017 East Asian mathematical journal Vol.33 No.1

Numerical solutions of the Rosenau-Burgers equation based on the cubic B-spline finite element method are introduced. The back- ward Euler method is used for discretization in time, and the obtained nonlinear algebraic system is changed to a linear system by the Newton’s method. We show that those methods are unconditionally stable. Two test problems are studied to demonstrate the accuracy of the proposed method. The computational results indicate that numerical solutions are in good agreement with exact solutions.

CUBIC B-SPLINE FINITE ELEMENT METHOD FOR THE ROSENAU-BURGERS EQUATION

Xu, Ge-Xing,Li, Chun-Hua,Piao, Guang-Ri The Youngnam Mathematical Society 2017 East Asian mathematical journal Vol.33 No.1

Numerical solutions of the Rosenau-Burgers equation based on the cubic B-spline finite element method are introduced. The backward Euler method is used for discretization in time, and the obtained nonlinear algebraic system is changed to a linear system by the Newton's method. We show that those methods are unconditionally stable. Two test problems are studied to demonstrate the accuracy of the proposed method. The computational results indicate that numerical solutions are in good agreement with exact solutions.

온라인 콘서트 시청자의 공동 체험을 위한 가상 환경 디자인 연구 -시청자의 몰입감과 향후 사용 의향을 중심으로-

갈욱(GE XU),박수진(Sujin Park),이상원(Sangwon Lee) 한국게임학회 2022 한국게임학회 논문지 Vol.22 No.1

COVID-19로 인해 비대면 문화 공연인 온라인 콘서트로 관람객에게 새로운 온라인 문화를 제공하고자 하는 노력이 다방면으로 점차 높아지고 있다. 그러나 현 시점의 온라인 콘서트는 오프라인 콘서트 중 다른 사람과의 상호작용을 온전히 살리지 못한다는 단점이 있다. 때문에 온라인 콘서트의 시청자에게 오프라인 콘서트와 같은 공통 경험을 제공하고자 한다. 본 연구는 관람객이 온라인 콘서트와 영화를 단독 및 그룹으로 시청하는 것으로 진행하였다. 연구 결과로 그룹으로 온라인 콘서트를 보는 것이 몰입감이 높아짐을 확인할 수 있었다. 향후 가상의 공동시청 환경의 디자인 가이드로 활용될 수 있음을 확인하였다. COVID-19 provided visitors with new online concerts that gradually increased in many ways. The disadvantage of current online concerts is that cannot make full use of the interaction with others. We hope to provide online concert audiences with the same experience as offline. This study was conducted under the condition that the audience watched online concerts and movies individually or group. Experimental results confirm that watching online concerts collectively will increase the sense of immersion. It can be used as a design guide for the virtual public viewing environment in the future.

Segmental Liver Stiffness Evaluated with Magnetic Resonance Elastography Is Responsive to Endovascular Intervention in Patients with Budd-Chiari Syndrome

Peng Xu,Lulu Lyu,Haitao Ge,Muhammad Umair Sami,Panpan Liu,Chunfeng Hu,Kai Xu 대한영상의학회 2019 Korean Journal of Radiology Vol.20 No.5

Objective: To assess segmental liver stiffness (LS) with MRI before and after endovascular intervention in patients with Budd-Chiari syndrome (BCS). Materials and Methods: Twenty-three patients (13 males and 10 females; mean age, 42.6 ± 12.6 years; age range, 31–56 years) with BCS as a primary liver disease were recruited for this study. Two consecutive magnetic resonance elastography (MRE) examinations were performed before the endovascular treatment. Fifteen patients who underwent endovascular intervention treatment also had follow-up MRE scans within three days after the procedure. LS was measured in three liver segments: the right posterior, right anterior, and left medial segments. Inter-reader and inter-exam repeatability were analyzed with intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Segmental LS and clinical characteristics before and after the intervention were also compared. Results: Within three days of the endovascular intervention, all three segmental LS values decreased: LS of the right posterior segment = 7.23 ± 0.88 kPa (before) vs. 4.94 ± 0.84 kPa (after), LS of the right anterior segment = 7.30 ± 1.06 kPa (before) vs. 4.77 ± 0.85 kPa (after), and LS of the left medial segment = 7.22 ± 0.87 kPa (before) vs. 4.87 ± 0.72 kPa (after) (all p = 0.001). There was a significant correlation between LS changes and venous pressure gradient changes before and after treatments (r = 0.651, p = 0.009). The clinical manifestations of all 15 patients significantly improved after therapy. The MRE repeatability was excellent, with insignificant variations (inter-reader, ICC = 0.839–0.943: inter-examination, ICC = 0.765–0.869). Bland–Altman analysis confirmed excellent agreement (limits of agreement, 13.4–19.4%). Conclusion: Segmental LS measured by MRE is a promising repeatable quantitative biomarker for monitoring the treatment response to minimally invasive endovascular intervention in patients with BCS.

Chemical processing of water-soluble species and formation of secondary organic aerosol in fogs

Kim, Hwajin,Collier, Sonya,Ge, Xinlei,Xu, Jianzhong,Sun, Yele,Jiang, Wenqing,Wang, Youliang,Herckes, Pierre,Zhang, Qi Elsevier 2019 Atmospheric environment Vol.200 No.-

<P><B>Abstract</B></P> <P>A field study on fog chemistry and aqueous-phase processing of aerosol particles was conducted in Fresno, California's San Joaquin Valley (SJV) during wintertime. Fog droplets were collected while interstitial submicron aerosol was characterized in real time using a High Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-AMS). The fog samples were later analyzed using HR-AMS, ion chromatography (IC), and total organic carbon analyzer (TOC). Compared to interstitial aerosol, dissolved solutes in fog waters were composed of higher fractions of ammonium, nitrate, sulfate, methanesulfonic acid, and oxygenated organic compounds, likely due to aqueous formation of secondary species as well as enhanced gas-to-particle partitioning of water-soluble gases under humid conditions. The low-volatility dissolved organic matter in fog water (F-OA) was moderately oxidized with an average oxygen-to-carbon (O/C) ratio of 0.42. The chemical composition of F-OA appeared to be overall similar to that of oxygenated organic component in interstitial aerosol (OOA) and the HR-AMS mass spectra of F-OA and OOA are highly similar (r<SUP>2</SUP> > 0.95). However, there are also significant chemical differences as F-OA appeared to contain a larger fraction of carboxylic functional groups than OOA, indicating enhanced organic acid formation through aqueous-phase reactions. In addition, F-OA was composed of substantially more nitrogen-containing compounds, with an average N/C ratio ∼4 times that of OOA. Most strikingly was that the F-OA spectra showed substantial enhancements of the C<SUB>x</SUB>H<SUB>y</SUB>N<SUB>2</SUB> <SUP>+</SUP> (x ≥ 0; y ≥ 0) ions, which were likely contributed by imidazole- and/or pyrazine-based compounds formed from the aqueous reactions of aldehydes with amino compounds. The results of this study demonstrated that aqueous reactions in atmospheric droplets can significantly modify aerosol composition and contribute to the formation of oxygenated and nitrogen-containing organic compounds in atmospheric aerosol particles. This finding is important for understanding aerosol's effects on human health, air quality, and climate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> HR-AMS study of fog processing of PM1 in San Joaquin Valley of CA during winter. </LI> <LI> Fog waters are enriched of secondary inorganic and organic aerosol species. </LI> <LI> Organic residuals in fog waters (FOM) is moderately oxidized (average O/C = 0.42). </LI> <LI> FOM has more abundant carboxylic acid and organic nitrogen compounds than OOA. </LI> <LI> This is evidence for forming imidazole- or pyrazine-based compounds in fog waters. </LI> </UL> </P>

Vagococcus zengguangii sp. nov., isolated from yak faeces

Ge Yajun,Jin Dong,Lai Xin-He,Yang Jing,Lu Shan,Huang Ying,Zheng Han,Zhang Xiaoyan,Xu Jianguo 한국미생물학회 2021 The journal of microbiology Vol.59 No.1

Two unknown Gram-stain-positive, catalase- and oxidasenegative, non-motile, and coccus-shaped bacteria, designated MN-17T and MN-09, were isolated from yaks faeces (Bos grunniens) in the Qinghai-Tibet Plateau of China. 16S rRNA gene sequence-based comparative analyses revealed that the two strains were grouped within the genus Vagococcus, displaying the highest similarity with Vagococcus xieshaowenii CGMCC 1.16436T (98.6%) and Vagococcus elongatus CCUG 51432T (96.4%). Both strains grew optimally at 37°C and pH 7.0 in the presence of 0.5% (w/v) NaCl. The complete genome of MN-17T comprises 2,085 putative genes with a total of 2,190,262 bp and an average G + C content of 36.7 mol%. The major fatty acids were C16:0 (31.2%), C14:0 (28.5%), and C18:1ω9c (13.0%); the predominant respiratory quinone was MK-7 (68.8%); the peptidoglycan type was A4α(L-Lys-DAsp); and the major polar lipid was diphosphatidylglycerol. Together, these supported the affiliation of strain MN-17T to the genus Vagococcus. In silico DNA-DNA hybridization and the average nucleotide identity values between MN-17T and all recognized species in the genus were 21.6–26.1% and 70.7–83.0%, respectively. MN-17T produced acid from D-cellobiose, D-fructose, glycerol, D-glucose, N-acetyl-glucosamine, gentiobiose, D-mannose, D-maltose, D-ribose, Dsaccharose, salicin, D-trehalose, and D-xylose. These results distinguished MN-17T and MN-09 from closely related species in Vagococcus. Thus, we propose that strains MN-17T and MN-09 represent a novel species in the genus Vagococcus, with the name Vagococcus zengguangii sp. The type strain is MN-17T (= CGMCC 1.16726T = GDMCC 1.1589T = JCM 33478T).

Unbalance Control Strategy of Boost Type Three-Phase to Single-Phase Matrix Converters Based on Lyapunov Function

Xu, Yu-xiang,Ge, Hong-juan,Guo, Hai The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.1

This paper analyzes the input side performance of a conventional three-phase to single-phase matrix converter (3-1MC). It also presents the input-side waveform quality under this topology. The suppression of low-frequency input current harmonics is studied using the 3-1MC plus capacitance compensation unit. The constraint between the modulation function of the output and compensation sides is analyzed, and the relations among the voltage utilization ratio and the output compensation capacitance, filter capacitors and other system parameters are deduced. For a 3-1MC without large-capacity energy storage, the system performance is susceptible to input voltage imbalance. This paper decouples the inner current of the 3-1MC using a Lyapunov function in the input positive and negative sequence bi-coordinate axes. Meanwhile, the outer loop adopts a voltage-weighted synthesis of the output and compensation sides as a cascade of control objects. Experiments show that this strategy suppresses the low-frequency input current harmonics caused by input voltage imbalance, and ensures that the system maintains good static and dynamic performances under input-unbalanced conditions. At the same time, the parameter selection and debugging methods are simple.

On the Bahadur representation of sample quantiles and order statistics for NA sequences

Xu, ShouFang,Ge, Li,Miao, Yu 한국통계학회 2013 Journal of the Korean Statistical Society Vol.42 No.1

In this paper, the Bahadur representation of sample quantiles for negatively associated (NA) sequences under mild conditions is established, which improves the results of Xing and Yang (2011). Furthermore, we also obtain the Bahadur representation of order statistics based on the NA sequences.

Surgical Options for Appropriate Length of J-Pouch Construction for Better Outcomes and Long-term Quality of Life in Patients with Ulcerative Colitis after Ileal Pouch-Anal Anastomosis

Xu Weimin,Tang Wenbo,Ding Wenjun,Hua Zhebin,Wang Yaosheng,Ge Xiaolong,Cui Long,Wu Xiaojian,Zhou Wei,Ding Zhao,Du Peng 거트앤리버 소화기연관학회협의회 2024 Gut and Liver Vol.18 No.1

Background/Aims: Total proctocolectomy with ileal pouch-anal anastomosis (IPAA) is widely accepted as a radical surgery for refractory ulcerative colitis (UC). Definite results on the appropriate pouch length for an evaluation of the risk-to-benefit ratio regarding technical complications and long-term quality of life (QOL) are still scarce. Methods: Data on UC patients who underwent IPAA from 2008 to 2022 in four well-established pouch centers affiliated to China UC Pouch Center Union were collected. Results: A total of 208 patients with a median follow-up time of 6.0 years (interquartile range, 2.3 to 9.0 years) were enrolled. The median lengths of the patients’ short and long pouches were 14.0 cm (interquartile range, 14.0 to 15.0 cm) and 22.0 cm (interquartile range, 20.0 to 24.0 cm), respectively. Patients with a short J pouch configuration were less likely to achieve significantly improved long-term QOL (p=0.015) and were prone to develop late postoperative complications (p=0.042), such as increased defecation frequency (p=0.003) and pouchitis (p=0.035). A short ileal pouch was an independent risk factor for the development of late postoperative complications (odds ratio, 3.100; 95% confidence interval, 1.519 to 6.329; p=0.002) and impaired long-term QOL improvement (odds ratio, 2.221; 95% confidence interval, 1.218 to 4.050, p=0.009). Conclusions: The length of the J pouch was associated with the improvement in long-term QOL and the development of late post-IPAA complications. A long J pouch configuration could be a considerable surgical option for pouch construction.