Flexural behavior of ultra high performance concrete beams reinforced with high strength steel

Jun-Yan Wang,Jin-Ben Gu,Chao Liu,Yu-Hao Huang,Ru-Cheng Xiao,Biao Ma 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.5

A detailed experimental program was conducted to investigate the flexural behavior of ultra high performance concrete (UHPC) beams reinforced with high strength steel (HSS) rebars with a specified yield strength of 600 MPa via direct tensile test and monotonic four-point bending test. First, two sets of direct tensile test specimens, with the same reinforcement ratio but different yield strength of reinforcement, were fabricated and tested. Subsequently, six simply supported beams, including two plain UHPC beams and four reinforced UHPC beams, were prepared and tested under four-point bending load. The results showed that the balanced-reinforced UHPC beams reinforced with HSS rebars could improve the ultimate loadbearing capacity, deformation capacity, ductility properties, etc. more effectively owing to interaction between high strength of HSS rebar and strain-hardening characteristic of UHPC. In addition, the UHPC with steel rebars kept strain compatibility prior to the yielding of the steel rebar, further satisfied the plane-section assumption. Most importantly, the crack pattern of the UHPC beam reinforced with HSS rebars was prone to transform from single main crack failure corresponding to the normal-strength steel, to multiple main cracks failure under the condition of balanced-reinforced failure, which validated by the conclusion of direct tensile tests cooperated with acoustic emission (AE) source locating technique as well.

Molecular Cloning and Characterization of a Novel Cold-Adapted Family VIII Esterase from a Biogas Slurry Metagenomic Library

( Xiao Jie Cheng ),( Xu Ming Wang ),( Tian Lei Qiu ),( Mei Yuan ),( Jiang Uang Sun ),( Jun Lian Gao ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.11

A novel esterase gene, est01, was successfully unearthed from a biogas digester microbiota metagenomic library. The 1,194 bp est01 gene encodes a protein of 44,804 Da (designated Est01). The amino acid sequence of Est01 shows only moderate (33%) identity to a lipase/ esterase. Phylogenetic analysis and biochemical characterization confirmed that Est01 is a new member of family VIII esterases. The purified Est01 from recombinant Escherichia coli BL21 (DE3) showed high hydrolytic activity against short-chain fatty acid esters, suggesting that it is a typical carboxylesterase rather than a lipase. Furthermore, the Est01 was even active at 10°C (43% activity remained), with the optimal temperature at 20°C, and had a broad pH range from 5.0 to 10.0, with the optimal pH of 8.0. These properties suggest that Est01 is a cold-adaptive esterase and could have good potential for low-temperature hydrolysis application.

Prediction of postoperative pancreatic fistula using a nomogram based on the updated definition

Cheng-Xiang Guo,Yi-Nan Shen,Qi Zhang,Xiao-Zhen Zhang,Jun-Li Wang,Shun-Liang Gao,Jian-Ying Lou,Ri-Sheng Que,Tao Ma,Ting-Bo Liang,Xue-Li Bai 대한외과학회 2020 Annals of Surgical Treatment and Research(ASRT) Vol.98 No.2

Purpose: The International Study Group on Pancreatic Fistula’s definition of postoperative pancreatic fistula (POPF) has recently been updated. This study aimed to identify risk factors for POPF in patients having pancreaticoduodenectomy (PD) and to generate a nomogram to predict POPF. Methods: Data on 298 patients who underwent PD from March 2012 to October 2017 was retrospectively reviewed and POPF statuses were redefined. A nomogram was constructed using data from 220 patients and validated using the remaining 78 patients. Independent risk factors for POPF were identified using univariate and multivariate analyses. A predictive nomogram was established based on the independent risk factors and was compared with existing models. Results: Texture of the pancreas, size of the main pancreatic duct, portal vein invasion, and definitive pathology were the identified risk factors. The nomogram had a C-index of 0.793 and was internally validated. The nomogram performed better (C-index of 0.816) than the other most cited models (C-indexes of 0.728 and 0.735) in the validation cohort. In addition, the nomogram can assign patients into low- (less than 10%), intermediate- (10% to 30%), and high-risk (equal or higher than 30%) groups to facilitate personalized management. Conclusion: The nomogram accurately predicted POPF in patients having PD.

Functional Magnetic Resonance Imaging in the Diagnosis of Locally Recurrent Prostate Cancer: Are All Pulse Sequences Helpful?

Xiao-Li Liao,Jun-Bao Wei,Yong-Qiang Li,Jian-Hong Zhong,Cheng-Cheng Liao,Chang-Yuan Wei 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.6

Objective: To perform a meta-analysis to quantitatively assess functional magnetic resonance imaging (MRI) in the diagnosis of locally recurrent prostate cancer. Materials and Methods: A comprehensive search of the PubMed, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews was conducted from January 1, 1995 to December 31, 2016. Diagnostic accuracy was quantitatively pooled for all studies by using hierarchical logistic regression modeling, including bivariate modeling and hierarchical summary receiver operating characteristic (HSROC) curves (AUCs). The Z test was used to determine whether adding functional MRI to T2-weighted imaging (T2WI) results in significantly increased diagnostic sensitivity and specificity. Results: Meta-analysis of 13 studies involving 826 patients who underwent radical prostatectomy showed a pooled sensitivity and specificity of 91%, and the AUC was 0.96. Meta-analysis of 7 studies involving 329 patients who underwent radiotherapy showed a pooled sensitivity of 80% and specificity of 81%, and the AUC was 0.88. Meta-analysis of 11 studies reporting 1669 sextant biopsies from patients who underwent radiotherapy showed a pooled sensitivity of 54% and specificity of 91%, and the AUC was 0.85. Sensitivity after radiotherapy was significantly higher when diffusion-weighted MRI data were combined with T2WI than when only T2WI results were used. This was true when meta-analysis was performed on a per-patient basis (p = 0.027) or per sextant biopsy (p = 0.046). A similar result was found when 1H-magnetic resonance spectroscopy (1H-MRS) data were combined with T2WI and sextant biopsy was the unit of analysis (p = 0.036). Conclusion: Functional MRI data may not strengthen the ability of T2WI to detect locally recurrent prostate cancer in patients who have undergone radical prostatectomy. By contrast, diffusion-weight MRI and 1H-MRS data may improve the sensitivity of T2WI for patients who have undergone radiotherapy.

Protectin DX increases alveolar fluid clearance in rats with lipopolysaccharideinduced acute lung injury

Xiao-Jun Zhuo,Yu Hao,Fei Cao,Song-Fan Yan,Hui Li,Qian Wang,Bi-Huan Cheng,Bin-Yu Ying,Bin-Yu Ying,Sheng-Wei Jin 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Acute respiratory distress syndrome is a life-threatening critical syndrome resulting largely from the accumulation of and the inability to clear pulmonary edema. Protectin DX, an endogenously produced lipid mediator, is believed to exert anti-inflammatory and pro-resolution effects. Protectin DX (5 μg/kg) was injected i.v. 8 h after LPS (14 mg/kg) administration, and alveolar fluid clearance was measured in live rats (n = 8). In primary rat ATII epithelial cells, protectin DX (3.605 × 10−3 mg/l) was added to the culture medium with LPS for 6 h. Protectin DX improved alveolar fluid clearance (9.65 ± 1.60 vs. 15.85 ± 1.49, p < 0.0001) and decreased pulmonary edema and lung injury in LPSinduced lung injury in rats. Protectin DX markedly regulated alveolar fluid clearance by upregulating sodium channel and Na, K-ATPase protein expression levels in vivo and in vitro. Protectin DX also increased the activity of Na, K-ATPase and upregulated P-Akt via inhibiting Nedd4–2 in vivo. In addition, protectin DX enhanced the subcellular distribution of sodium channels and Na, K-ATPase, which were specifically localized to the apical and basal membranes of primary rat ATII cells. Furthermore, BOC-2, Rp-cAMP, and LY294002 blocked the increased alveolar fluid clearance in response to protectin DX. Protectin DX stimulates alveolar fluid clearance through a mechanism partly dependent on alveolar epithelial sodium channel and Na, K-ATPase activation via the ALX/PI3K/Nedd4–2 signaling pathway.

Restrained Shrinkage Mechanism of Ultra High Performance Concrete

Jun-Yan Wang,Chen Bian,Ru-Cheng Xiao,Biao Ma 대한토목학회 2019 KSCE Journal of Civil Engineering Vol.23 No.10

The understanding and controlling of the restrained shrinkage is critical for the application of ultra high performance concrete(UHPC). This study made an analysis of restrained shrinkage mechanism of four kinds of UHPCs based on the direct tensile test accompanied with acoustic emission (AE) source location, free shrinkage test and restrained shrinkage test. The effects of UHPC tensile properties (strain softening or strain hardening) and high performance calcium sulphoaluminate (HCSA, a new kind of expansion agent) dosages (0%, 3% and 6% by mass of total binder) were investigated. The restrained shrinkage cracking mechanism of strain hardening UHPC and strain softening UHPC was analyzed based on AE analysis method under direct tensile loading. The results indicates that strain hardening UHPC shows multiple micro-defects to relax the restrained tensile stress marginally while strain softening UHPC shows several hairline cracks to relax the restrained tensile stress evidently. In ASTM C1581-04 ring test, the restrained shrinkage of strain hardening UHPC with HCSA dosage of 0%, 3% and 6% at 80d is 141 με, 96 με and 16 με, respectively. The HCSA expansion agent can effectively reduce the restrained shrinkage of UHPC and the influence on the structure.

Glycerol steam reforming over Ni/γ-Al2O3 catalysts modified by metal oxides

Cheng-Hua Xu,Zun-Yu Huang,Chuan-Qi Liu,Hui-Wen Xiao,Jun Chen,Yong-Xiang Zhang,Ya-Cong Lei 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.3

The metal oxides modified Ni/γ-Al2O3 catalysts for glycerol steam reforming were prepared by impregnation. Characterization results of fresh catalysts indicated that the molybdates modification abated the acidity and the stronger metal-support interaction of Ni/γ-Al2O3 catalysts, leading to a stable catalytic activity. Especially, NiMoLa-CaMg/γ-Al2O3 (NiMoLa/CMA) catalyst exhibited no deactivation along with glycerol complete conversion to stable gaseous products containing 69% H2, 20% CO and 10% CO2 during time-on-stream of 42 h. TPO of spent Ni/γ-Al2O3catalysts modified by different components showed that the carbon deposit on acidic sites and NiAl2O4 species led to catalysts deactivation. A lower reforming temperature and a higher LHSV and glycerol content were helpful to the production of syngas from GSR over NiMoLa/CMA; the reverse conditions would improve the formation of H2.

Experimental investigation on the behaviour of UHPC-steel composite slabs under hogging moment

Xiao-Long Gao,Jun-Yan Wang,Chen Bian,Ru-Cheng Xiao,Biao Ma 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.6

Ultra high performance concrete (UHPC) can be used in the UHPC-steel composite structures especially for bridge structures to achieve high stiffness and high fatigue resistance with low self-weight. The structural performances of UHPC-steel composite slabs subjected to hogging moment have a significant influence on the global stiffness and durability of UHPC-steel composite structures. In order to study the structural behaviors of non-steam-cured UHPC-steel composite slabs subjected to negative moment, five composite slabs combined the thin UHPC layers to steel plates via shear stud connecters with the diameter of 16mm were fabricated and tested under negative moment. The test program aimed to investigate the effect of stud spacing and longitudinal reinforcement ratios on the failure mode, load-deflection behaviors, cracking patterns, bond-slips, and carrying capacities of composite slabs subjected to negative moment. In addition, direct tensile tests for the dog-bone UHPC specimens with longitudinal reinforcement bars were carried out to study the effect of reinforcement bars on the tensile strength of UHPC in the thin structure members. Based on the experimental results, analytical models were also developed to predict the cracking load and ultimate load of UHPC-steel composite slabs subjected to negative moment.

주제별 논단 : 한,중 금융협력의 법적 과제와 전망 ; 중국금융관리감독체제의 현황과 문제점

강정소 ( Cheng Xiao Jiang ),이애군 ( Ai Jun Li ) 한국금융법학회 2012 金融法硏究 Vol.9 No.2

본문은 중국금융관리감독체제의 역사 연혁을 소개하고 현재 중국금융관리감독에서 존재하는 주요 문제를 분석하며 동시에 해결방안을 제시한다. 본문의 주장은, 중국의 역사와 문화전통, 경제금융환경, 정치배경의 영향, 특히 금융업의 종합적 경영발전 정도를 충분히 고려한 바탕으로 중국의 관리감독체제를 순차적이고 점진적으로 개혁을 추진하여야 한다 현 단계 중국은 분립된 관리 감독체제를 유지해야 하고 동시에 각방면으로 종합경영활동에 대한 관리감독제도를 점차 설립하여야 한다 예를 들면 관리감독기관의 독립성과 전문지식 수준을 제고하고 관리감독기관과 다른 거시적 조절부서 간의 협조를 강화하며 금융법률체제를 개선한다 등 내용이 있다. This paper has introduced China`s historical evolution of financial supervision system and analyzed the current China`s historical evolution of financial supervision system and analyzed the current China`s main existing problem of financial supervision. Also this paper puts forward some Suggestions to solve the problem. This paper suggests that we should reform and perfect China`s present financial supervisory system step by step gradually, fully considering China`s historical and cultural traditions, economic and financial environments and political background. Nowadays China should still stick to the multiple supervisory systems, but we need to set up the supervisory system arrangements about the comprehensive operation activities in every respect at the same time. For example, we should do what we do to enhance the independence and specialization level of the supervisory institutions, to harmonize the activities between the supervisory institutions and other macro-control departments, to build and perfect the financial legal system, and so on.

Research on the Critical Condition of Brittle-Ductile Transition about Micro-Milling of KDP Crystal and Experimental Verification

Yong Xiao,Ming-Jun Chen,Yan-Ting Yang,Jian Cheng 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

KDP crystal is a kind of brittle material, and improper selection of processing parameter can easily result in brittle domain cuttingof KDP crystal. Determining the critical cutting depth of micro-milling brittle-ductile transition of KDP crystal can guide the selectionof process parameters. The elastic-plastic contact formula of blunt spherical indenter and brittle materials is used to explicate thecontact of micro-cutter edge and brittle materials. Combined with indentation critical load equation, the calculation model ofpredicting the critical cutting depth is established. The critical cutting depth is the function of material properties of the workpiece,the tool material properties and the tool edge radius. The edge radius of CBN flat end milling cutter is measured by atomic forcemicroscopy, and then the critical cutting depth of the KDP crystal material is calculated as 230 nm. By using this milling cutter, microgroovemilling experiments are conducted with different spindle speeds and feeds. The results demonstrate that as the spindle speedincreases, the micro-groove bottom surface gradually transformed from the brittle cutting state to plastic cutting state. The criticalspindle speed is 30000 rpm, and the maximum deformed cutting thickness is 227 nm, which coincides with the result of the theoreticalcalculation model.