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- 저자 : Yafei Ma (검색결과 5 건)
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Yanyan Ma,Yanlei Su,Yafei Li,Zhongyi Jiang 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.9
Composite nanofiltration (NF) membranes with enhanced structural stability were fabricated and used to concentrate oligomeric proanthocyanidins (OPC) in ethanol solution. The composite NF membranes were prepared by interfacial polymerization of piperazine (PIP) with trimesoyl chloride (TMC), upon the porous supports of polyethersulfone (PES) and polyvinyl formal (PVF) blend membranes. The active layers of composite NF membranes were covalently linked to porous supports owing to hydroxyl groups of PVF upon support surface, which could participate in the interfacial polymerization reaction. The pure water fluxes of the composite NF membranes reached 34.9 L/m2h, while the rejections of Na2SO4 and orange GII were 92.7% and 98.4%, respectively. The enhanced structural stability of the composite NF membranes were confirmed by long-term immersion experiment in ethanol. NF concentration process was considered as a potential alternative to conventional evaporation concentration process for OPC concentration in ethanol solution.
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Occlusal deviations in adolescents with idiopathic and congenital scoliosis
Zhang Hao,Ma Jingbo,Zhang Zhicheng,Feng Yafei,Cai Chuan,Wang Chao 대한치과교정학회 2022 대한치과교정학회지 Vol.52 No.3
Objective: This cross-sectional study aimed to investigate the characteristics of malocclusions in scoliotic patients through clinical examinations. Methods: Fifty-eight patients with idiopathic scoliosis (IS) and 48 patients with congenital scoliosis (CS) participated in the study. A randomly selected group of 152 orthopedically healthy children served as the control group. Standardized orthodontic and orthopedic examination protocols were used to record the occlusal patterns and type of scoliosis. Assessments were made by three experienced orthodontists and a spinal surgery team. The differences in the frequency distribution of occlusal patterns were evaluated by the chi-squared test. Results: In comparison with patients showing IS, patients with CS showed a higher incidence of Cobb angle ≥ 45° (p = 0.020) and included a higher proportion of patients receiving surgical treatments (p < 0.001). The distribution of the Angle Class II subgroup was significantly higher in the IS (p < 0.001) and CS (p = 0.031) groups than in the control group. In comparison with the healthy controls, the CS and IS groups showed significantly higher (p < 0.05) frequencies of asymmetric molar and asymmetric canine relationships, upper and lower middle line deviations, anterior deep overbite, unilateral posterior crossbite, and canted occlusal plane, with the frequencies being especially higher in CS patients and to a lesser extent in IS patients. Conclusions: Patients with scoliosis showed a high frequency of malocclusions, which were most obvious in patients with CS.
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Yuegao Liu,Xinbiao Lv,Longshuai Yang,Hufei Wang,Yafei Meng,Qie Yi,Bo Zhang,Jianliang Wu,Jian Ma 한국지질과학협의회 2015 Geosciences Journal Vol.19 No.4
Permian mafic-ultramafic intrusions in or besides the Central Asian Orogenic Belt (CAOB) have been the focus of several recent studies, mainly located in Altay, East Tianshan, and Beishan Rift from north to south. Some of them host economic magmatic sulfide deposits. Among those, Poyi is a large magmatic Cu-Ni sulfide deposit related to ultramafic rock in Beishan Rift. Poyi does not have massive ore, but only disseminated ore in hornblende- peridotite, so Poyi is not as rich as the Karatongk Cu-Ni deposit in the Altay area or the Huangshandong and Tulargen Cu- Ni sulfide deposits in Eastern Tianshan. To address these questions, this paper contrasts the feature of PGE (Platinum Group Element) and olivine composition in magmatic Cu-Ni deposits between three regions (Altay, East Tianshan, and Beishan Rift) to provide a view of the metallogenic process of the Poyi magmatic Cu-Ni deposit. The degree of sulfide segregation (DSS) of Poyi is around 0.01%; the value of R (the ratio of the mass of silicate magma to the mass of sulfide that reached equilibrium together) is 500–5000, and is 2333 on average; the R value of Cu-Ni sulfide deposits in East Tianshan is in the range of 100–500, and the degree of sulfide segregation is about 0.013%; Poyi Cu-Ni deposit is not as rich as the magmatic Cu-Ni deposits in East Tianshan, probably because the degree of sulfide segregation of the former (0.01%) is lower than that of the latter (0.013%). From Beishan area to East Tianshan and then to Altay Region, the R value changed from 2333 to 100–500 and then to 100 according to the theory of Naldrett (2011). Poyi does not have the potential to be a PGE deposit. The olivine of Poyi has higher contents of MgO and SiO2 and lower contents of FeO and CaO, which reach sulfur saturation more easily, but due to the lack of sulfur, it is still very difficult to reach sulfur saturation, and therefore the olivine of Poyi has the highest Ni content among the Permian magmatic Cu-Ni deposits in Xinjiang.
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Shear Behavior of Corroded Post-Tensioned Prestressed Concrete Beams with Full/Insufficient Grouting
Lei Wang,Zhuo Hu,Ju Yi,Lizhao Dai,Yafei Ma,Xuhui Zhang 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.6
This paper experimentally studied the shear behavior of corroded post-tensioned prestressed concrete beams with full grouting. The effects of insufficient grouting in shear span on the shear behavior were also investigated. Eight beams were fabricated and divided into two groups: four beams with full grouting and four beams with insufficient grouting. Three beams in each group were subjected to accelerated corrosion. All beams were tested to failure in four-point loading. Experimental data on shear cracking, load-deflection response, shear strength and failure modes were presented. Results showed that strand corrosion accelerated the formation and propagation of diagonal crack. Insufficient grouting decreased the number of diagonal cracks. Strand corrosion degraded the post-cracking stiffness and shear strength. Insufficient grouting aggravated the propagation of diagonal crack and the degradation of post-cracking stiffness. The shear strength of corroded beam with 31.7% corrosion loss decreased by 15.44% as compared to that of the uncorroded beam. Strand corrosion loss less than 31.7% did not change the shear compression failure mode in fully grouted beams. The failure modes of locally ungrouted beams changed from shear compression failure to rupture of wires as the corrosion loss exceeded 39.6%.
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