The Effects of Electro Slag Welding on Material Properties of Box Column Plates

Cheng-Cheng Chen,Yu-Chen Liang2 한국강구조학회 2011 International Journal of Steel Structures Vol.11 No.2

The effects of electro slag welding (ESW) on the material properties of box column plates, which is ASTM A572 Gr. 50steel, were investigated experimentally and numerically. The material properties of the column plates before and after ESW were evaluated by macro-etching observation, micro-structural observation, and CVN impact tests. The temperature distribution of the column plates, with the ESW heat cycle as the heat input, was simulated by using the ANSYS FEM software. It was found that: (1) The CVN values in the through thickness direction of the base metal can be as low as 14J, 8.1J, and 8.1J at 0oC for plate thicknesses of 32, 40, and 50 mm respectively; (2) During the ESW process, the measured peak temperature for a 25×50 mm column plate surface was as high as 1033, 880 and 744oC for plate thicknesses of 32, 40 and, 50 mm respectively;(3) After the ESW heat cycle, the through thickness CVN value decreased by 68% for the coarse grain heat affected zone (HAZ) of the column pate; (4) The FEM thermal conduction model developed was able to simulate the temperature distribution of the steel plate during the ESW process with reasonable accuracy; (5) To avoid welding penetration due to ESW, a minimum plate thickness is suggested; (6) The impact of ESW heat cycle is more significant for thin column plates compared to thick ones.

Mechanical behavior of stud shear connectors embedded in HFRC

Yu-Liang He,Xu-Dong Wu,Yiqiang Xiang,Yu-Hang Wang,Li-Si Liu,Zhi-Hai He 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.24 No.2

Hybrid-fiber reinforced concrete (HFRC) may provide much higher tensile and flexural strengths, tensile ductility, and flexural toughness than normal concrete (NC). HFRC slab has outstanding advantages for use as a composite bridge potential deck slab owing to higher tensile strength, ductility and crack resistance. However, there is little information on shear connector associated with HFRC slabs. To investigate the mechanical behavior of the stud shear connectors embedded in HFRC slab, 14 push-out tests (five batches) in HFRC and NC were conducted. It was found that the stud shear connector embedded in HFRC had a better ductility, higher stiffness and a slightly larger shear bearing capacity than those in NC. The experimentally obtained ultimate resistances of the stud shear connectors were also compared against the equations provided by GB50017 2003, ACI 318-112011, AISC 2011, AASHTO LRFD 2010, PCI 2004, and EN 1994-1-1 (2004), and an empirical equation to predict the ultimate shear connector resistance considering the effect of the HFRC slabs was proposed and validated by the experimental data. Curve fitting was performed to find fitting parameters for all tested specimens and idealized load-slip models were obtained for the specimens with HFRC slabs.

The Impact of Excess Pore Pressure on the Support Stability of a Shield When Tunnelling in Sand Stratum

Yu Liang,Jian Zhang,Xiangyu Chen 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.8

When the large-diameter shield tunneling through the soft soil stratum, the pore pressure fluctuation would influence the tunnel stability, yet how it affected was still hard to figure out. Based on field tests data collected from a tunnel project in China, the distribution characteristics of excess pore pressure in sand stratum were obtained. By combining the limit equilibrium theory and variational calculus method, a modified formula of the limit support pressure was proposed, considering the effects of excess pore pressure and slope angle. The results showed that the excess pore water pressure had a big influence on the fracture angel of the sliding surface and the support pressure of the shield. If the effect of the pore pressure were taken into account, the support pressure should be set larger than the normal condition when the shield entered sand layer. The limit support pressure would decrease with the increase of the cohesive force and friction angle. Thus, effective reinforcement on the stratum should be adopted before the shield passing through.

One-Step Construction of Ni/Co-Doped C–N Nanotube Composites as Excellent Cathode Catalysts for Neutral Zinc–Air Battery

Liang Yu,Qingfeng Yi,Xiaokun Yang,Xiulin Zhou 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.3

Development of a neutral Zn–air battery is of much significance due to the high stability of zinc in a neutral electrolyte. Here, Ni/Co-doped C–N nanotube composites (C–N, Ni/C–N, Co/C–N, and Ni–Co/C–N) as efficient oxygen reduction reaction (ORR) electrocatalysts in a neutral medium have been prepared by direct pyrolysis of Ni/Co salt, dicyandiamide (DCD) and glucose. Among the synthesized catalysts, Ni–Co/C–N presents a high ORR current density of 8.5mA · cm -2 in a 0.5 mol · L -1 KNO3 solution. The ORR electron transfer number of the catalyst Ni–Co/C–N is 3.8, indicating that O2 is almost completely reduced to H2O. A neutral zinc–air battery utilizing a 0.5 mol · L -1 KNO3 solution has been assembled by using the prepared composite catalyst coated on carbon paper as an air cathode, and Zn plate as an anode. The battery with the cathode catalyst Ni–Co/C–N delivers the open-circuit voltage of 1.13 V and the maximum power density of 65mW · cm -2. The constant discharge current density of 50mA · cm -2, 100 mA · cm -2 and 150mA · cm -2 can last 202 h, 93 h and 11 h, respectively. A stable voltage plateau appears at various discharge current densities. The neutral zinc–air battery can be repeatedly discharged after replacing the zinc anode. Results indicate that the synthesized Ni–Co/C–N catalyst is an excellent cathode material applied to a neutral zinc–air battery, showing broad application prospects as a mobile power source.

An application of quantitative feedback theory in a 3D active vibration isolation platform

Yu-Liang Chung,Meng Shiun Tsai,Jen-Hua Wu 한국소음진동공학회 2003 한국소음진동공학회 국제학술대회논문집 Vol.2003 No.8

HEREDITARILY HYPERCYCLICITY AND SUPERCYCLICITY OF WEIGHTED SHIFTS

Yu-Xia Liang,Ze-Hua Zhou 대한수학회 2014 대한수학회지 Vol.51 No.2

In this paper we first characterize the hereditarily hyper- cyclicity of the unilateral (or bilateral) weighted shifts on the spaces L² (N,K) (or L²(Z,K)) with weight sequence {An} of positive invert- ible diagonal operators on a separable complex Hilbert space K. Then we give the necessary and sufficient conditions for the supercyclicity of those weighted shifts, which extends some previous results of H. Salas. At last, we give some conditions for the supercyclicity of three different weighted shifts.

재정적 위기가 중국의 재정 개혁에 미치는 영향

Yu Liang Fu 단국대학교 사회과학연구소 2009 공공정책과 국정관리 Vol.3 No.1

Seismic response of combined retaining structure with inclined rock slope

Yu-liang Lin,Jie Jin,Zhi-hao Jiang,Wei Liu,Hai-dong Liu,Rou-feng Li,Xiang Liu 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.5

A gravity wall combined with an anchoring lattice frame (a combined retaining structure) is adopted at a typical engineering site at Dali-Ruili Railway Line China. Where, the combined retaining structure supports a soil deposit covering on different inclined rock slopes. With an aim to investigate and compare the effects of inclined rock slopes on the response of combined retaining structure under seismic excitation, three groups of shaking table tests are conducted. The rock slopes are shaped as planar surfaces inclined at angles of 20°, 30°, and 40° with the horizontal, respectively. The shaking table tests are supplemented by dynamic numerical simulations. The results regarding the horizontal acceleration response, vertical acceleration response, permanent displacement mode, and axial anchor force are comparatively examined. The acceleration response is more susceptible to outer structural profile of combined retaining structure than to inclined angle of rock slope. The permanent displacement decreases when the inclined angle of the rock slope increases within a range of 20°-40°. A critical inclined angle of rock slope exists within a range of 20°-40°, and induces the largest axial anchor force in the combined retaining structure.

Prevalence, Risk Factors, and Psychological Effects of Overactive Bladder in Chinese University Students

Yu Liang,Guo Wei Si,Hui Jie Hu,Zhen Wei Zhang,Cui Ping Song,Qi Feng Dou,Jian Guo Wen 대한배뇨장애요실금학회 2022 International Neurourology Journal Vol.26 No.4

Purpose: The purpose of this study was to investigate the prevalence and risk factors of overactive bladder (OAB) in young adults and to explore the influence of OAB on mental health. Methods: Between October 2019 and January 2020, 14,010 anonymous questionnaires were distributed to freshmen at 2 universities in Henan, China. The students came from all over the country. The questionnaire included general items and information necessary to calculate the overactive bladder symptom score, the Chinese version of the Pittsburgh Sleep Quality Index (PSQI) score, Self-Esteem Scale (SES) score, and Self-Rating Depression Scale (SDS) score. The relationships between the prevalence of OAB and its risk factors were evaluated. Results: The overall prevalence of OAB was 6.0%, with 4.3% of participants characterized as having dry OAB and 1.7% as having wet OAB. The prevalence of mild OAB was 5.5%, and that of moderate OAB was 0.5%; no severe OAB was observed. Higher prevalence rates of OAB were found among women, respondents with constipation, and respondents with primary nocturnal enuresis (PNE) (P <0.05). Compared to healthy controls, the OAB group exhibited a higher mean SDS score (52.12±8.986 vs. 47.71±9.399, P<0.001) and mean PSQI score (5.28±2.486 vs. 4.27±2.431, P<0.001), but a lower mean SES score (27.78±3.599 vs. 29.57±4.109, P<0.001). Conclusions: OAB significantly affects the mental health of young adults. Female sex, constipation, and PNE are risk factors for OAB.

The National Health Insurance Research Database (NHIRD)

Liang-Yu Lin,Charlotte Warren-Gash,Liam Smeeth,Pau-Chung Chen 한국역학회 2018 Epidemiology and Health Vol.40 No.-

Electronic health records (EHRs) can provide researchers with extraordinary opportunities for population based research. The National Health Insurance system of Taiwan was established in 1995 and covers more than 99.6% of the Taiwanese population; this system’s claims data are released as the National Health Insurance Research Database (NHIRD). All data from primary outpatient departments and inpatient hospital care settings are included in this database. After a change and update in 2016, the NHIRD is maintained and regulated by the Data Science Centre of the Ministry of Health and Welfare of Taiwan. Datasets for approved research are released in three forms: sampling datasets comprising two million subjects, disease-specific datasets, and full population datasets. These datasets are de-identified and contain basic demographic information, disease diagnoses, prescriptions, operations, and investigations. Data can be linked to governmental surveys or other research datasets. While only a small number of validation studies with small sample sizes have been undertaken, they generally report positive predictive values of over 70% across different diagnoses. Currently, patients cannot opt out of inclusion in the database, though this requirement is under review. In conclusion, the NHIRD is a large, powerful data source for biomedical research.