Effect of High-energy Ball Milling on the Mg Alloy Powders under Alcohol Protection

Li Gang,Liu Xingxing,Guo Qi,Tang Jianren,Yan Biao 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Study about the feasibility and effect of high-energy ball milling on a specific Mg alloy under protection medium of alcohol was presented via comparing with conventional vacuum milling. More fine particles with wider powder size distribution but more irregular shape were shown of the powder milled under alcohol. No obvious oxide was revealed from the two kinds of Mg alloy powders with limited milling time. And since slip induced in a preferential direction, the (002) texture was formed in the Mg alloy powders at the initial stage of alcohol milling. More O and Fe contaminants were introduced into the powders milled under alcohol according to the EDS analysis.

Photosynthetic carbon fixation by tropical coral reef phytoplankton assemblages: a UVR perspective

Li, Gang,Che, Zhiwei,Gao, Kunshan The Korean Society of Phycology 2013 ALGAE Vol.28 No.3

Photosynthetic carbon fixation regulates air-sea $CO_2$ fluxes in the waters of coral reefs. However, little has been documented on the effects of solar UV radiation (UVR, 280-400 nm) upon photosynthetic behaviors of phytoplankton dwelling in these ecosystems. In order to evaluate the aforesaid, surface dwelling tropical coral reef phytoplankton assemblages collected from the South China Sea were exposed to solar radiation (i.e., photosynthetically active radiation [PAR] + UV radiation A [UVA] + UV radiation B [UVB], 280-700 nm; PAR + UVA, 320-700 nm; and PAR, 400-700 nm) under static or simulated-mixing conditions. Under the static condition, UVA and UVB significantly reduced the carbon fixation with the maximum of 22.4 and 15.3%, respectively; while lower UVR-related photosynthetic inhibition was observed in case of phytoplankton samples being subjected to mixing. At a moderate level of mixing (i.e., circulation time 80 min), the UVA and UVB caused inhibition were lowered by 52.1 and 79.6%, respectively. Based on this it could be stated that vertical mixing induced by winds and/or tides in the natural environments could reduce the inhibitory effect of solar UVR on phytoplankton productivity in the coral reefs water.

Effects of solar UV radiation on photosynthetic performance of the diatom Skeletonema costatum grown under nitrate limited condition

Li, Gang,Gao, Kunshan The Korean Society of Phycology 2014 ALGAE Vol.29 No.1

Availability of nutrients is known to influence marine primary production; and it is of general interest to see how nutrient limitation mediates phytoplankton responses to solar ultraviolet radiation (UVR, 280-400 nm). The red tide diatom Skeletonema costatum was cultured under nitrate (N)-limited and N-replete conditions and exposed to different solar irradiation treatments with or without UV-A (315-400 nm) and UV-B (280-315 nm) radiation. Its photochemical quantum yield decreased by 13.6% in N-limited cells as compared to that in N-replete ones under photosynthetically active radiation (PAR)-alone treatment, and the presence of UV-A or UV-B decreased the yield further by 2.8 and 3.1%, respectively. The non-photochemical quenching (NPQ), when the cells were exposed to stressful light condition, was higher in N-limited than in N-replete grown cells by 180% under PAR alone, by 204% under PAR + UV-A and by 76% under PAR + UV-A + UV-B treatments. Our results indicate that the N limitation exacerbates the UVR effects on the S. costatum photosynthetic performance and stimulate its NPQ.

Targeted Silencing of Inhibitors of Apoptosis Proteins with siRNAs: A Potential Anti-cancer Strategy for Hepatocellular Carcinoma

Li, Gang,Chang, Hong,Zhai, Yun-Peng,Xu, Wei Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

Hepatocellular carcinoma (HCC) is one of the most common malignancies, with a very poor prognosis. Despite significant improvements in diagnosis and treatment in recent years, the long-term therapeutic efficacy is poor, partially due to tumor metastasis, tecurrence, and resistance to chemo-or radio-therapy. Recently, it was found that a major feature of tumors is a combination of unrestrained cell proliferation and impaired apoptosis. There are now 8 recogized members of the IAP-family: NAIP, c-IAP1, c-IAP2, XIAP, Survivin, Bruce, Livin and ILP-2. There proteins all contribute to ingibition of apoptosis, and provide new potential avenues of cancer treatment. As a powerful tool to suppress gene expression in mammalian cells, RNAi species for inhibiting IAP genes cab be directed against cancers. This review will provide a brief introduction to recent developments of the application IAP-siRNA in tumor studies, with the aim of inspiring future treatment of HCC.

Acceleration method for computer generated spherical hologram calculation of real objects using graphics processing unit

Li, Gang,Hong, Keehoon,Yeom, Jiwoon,Chen, Ni,Park, Jae-Hyeung,Kim, Nam,Lee, Byoungho Science in China Press 2014 Chinese optics letters Vol.12 No.6

Graphics processing unit (GPU) based fast calculation method for computer generated spherical hologram (CGSH) of a real-existing object is proposed. Three-dimensional (3D) point cloud is constructed by capturing a real-existing object from multiple directions using a depth camera. The GPU based calculation is used in both hologram generation part and numerical reconstruction part of the CGSH. The improved calculation efficiency is verified by comparing the computation speed between central processing unit (CPU) based and GPU based implementation.

Space bandwidth product enhancement of holographic display using high-order diffraction guided by holographic optical element

Li, Gang,Jeong, Jinsoo,Lee, Dukho,Yeom, Jiwoon,Jang, Changwon,Lee, Seungjae,Lee, Byoungho The Optical Society 2015 Optics express Vol.23 No.26

Mapping Longitudinal Development of Local Cortical Gyrification in Infants from Birth to 2 Years of Age

Li, Gang,Wang, Li,Shi, Feng,Lyall, Amanda E.,Lin, Weili,Gilmore, John H.,Shen, Dinggang Society for Neuroscience 2014 The Journal of neuroscience Vol.34 No.12

<P>Human cortical folding is believed to correlate with cognitive functions. This likely correlation may have something to do with why abnormalities of cortical folding have been found in many neurodevelopmental disorders. However, little is known about how cortical gyrification, the cortical folding process, develops in the first 2 years of life, a period of dynamic and regionally heterogeneous cortex growth. In this article, we show how we developed a novel infant-specific method for mapping longitudinal development of local cortical gyrification in infants. By using this method, via 219 longitudinal 3T magnetic resonance imaging scans from 73 healthy infants, we systemically and quantitatively characterized for the first time the longitudinal cortical global gyrification index (GI) and local GI (LGI) development in the first 2 years of life. We found that the cortical GI had age-related and marked development, with 16.1% increase in the first year and 6.6% increase in the second year. We also found marked and regionally heterogeneous cortical LGI development in the first 2 years of life, with the high-growth regions located in the association cortex, whereas the low-growth regions located in sensorimotor, auditory, and visual cortices. Meanwhile, we also showed that LGI growth in most cortical regions was positively correlated with the brain volume growth, which is particularly significant in the prefrontal cortex in the first year. In addition, we observed gender differences in both cortical GIs and LGIs in the first 2 years, with the males having larger GIs than females at 2 years of age. This study provides valuable information on normal cortical folding development in infancy and early childhood.</P>

Synthesis of computer-generated spherical hologram of real object with 360° field of view using a depth camera

Li, Gang,Phan, Anh-Hoang,Kim, Nam,Park, Jae-Hyeung The Optical Society 2013 Applied optics Vol.52 No.15

<P>A method for synthesizing a 360 computer-generated spherical hologram of real-existing objects is proposed. The whole three-dimensional (3-D) information of a real object is extracted by using a depth camera to capture multiple sides of the object. The point cloud sets which are obtained from corresponding sides of the object surface are brought into a common coordinate system by point cloud registration process. The modeled 3-D point cloud is then processed by hidden point removal method in order to identify visible point set for each spherical hologram point. The hologram on the spherical surface is finally synthesized by accumulating spherical waves from visible object points. By reconstructing partial region of the calculated spherical hologram, the corresponding view of the 3-D real object is obtained. The principle is verified via optical capturing using a depth camera and numerical reconstructions.</P>

A hybrid simulated annealing and optimality criteria method for optimum design of RC buildings

Li, Gang,Lu, Haiyan,Liu, Xiang Techno-Press 2010 Structural Engineering and Mechanics, An Int'l Jou Vol.35 No.1

This paper proposes a hybrid heuristic and criteria-based method of optimum design which combines the advantages of both the iterated simulated annealing (SA) algorithm and the rigorously derived optimality criteria (OC) for structural optimum design of reinforced concrete (RC) buildings under multi-load cases based on the current Chinese design codes. The entire optimum design procedure is divided into two parts: strength optimum design and stiffness optimum design. A modified SA with the strategy of adaptive feasible region is proposed to perform the discrete optimization of RC frame structures under the strength constraints. The optimum stiffness design is conducted using OC method with the optimum results of strength optimum design as the lower bounds of member size. The proposed method is integrated into the commercial software packages for building structural design, SATWE, and for finite element analysis, ANSYS, for practical applications. Finally, two practical frame-shear-wall structures (15-story and 30-story) are optimized to illustrate the effectiveness and practicality of the proposed optimum design method.

Minimum life-cycle cost design of ice-resistant offshore platforms

Li, Gang,Zhang, Da-Yong,Yue, Qian-Jin Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.1

In China, the oil and natural gas resources of Bohai Bay are mainly marginal oil fields. It is necessary to build both ice-resistant and economical offshore platforms. However, risk is involved in the design, construction, utilization, maintenance of offshore platforms as uncertain events may occur within the life-cycle of a platform under the extreme ice load. In this study, the optimum design model of the expected life-cycle cost for ice-resistant platforms based on cost-effectiveness criterion is proposed. Multiple performance demands of the structure, facilities and crew members, associated with the failure assessment criteria and evaluation functions of costs of construction, consequences of structural failure modes including damage, revenue loss, death and injury as well as discounting cost over time are considered. An efficient approximate method of the global reliability analysis for the offshore platforms is provided, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. The proposed life-cycle optimum design formula are applied to a typical ice-resistant platform in Bohai Bay, and the results demonstrate that the life-cycle cost-effective optimum design model is more rational compared to the conventional design.