Study of Robustness Approximate Time-Optimal System

Xu, Song Yuan,Yao, Li Qiang,Rong, Hong Bing,Xu, Shao Qing 대한전자공학회 1992 HICEC:Harbin International Conference on Electroni Vol.1 No.1

Using the $quot;bang-bang$quot;control the system can obtain the optimal time. But there have the chatter and the bad robustness after considering the practical factors. If we use the chang structure principle, the chatter will be diminated and the system will get the strong robustness. This paper adopted this two kinds of the principles to design the satellite attitute control system and the satisfied results were received.

Hydrocarbon migration and accumulation history in deep reservoirs: a case study of Mesozoic sandstone gas reservoirs in the Kelasu-Yiqikelike structural belt of the Kuqa Depression, Tarim Basin

Xu Song,Xiuxiang Lü,Yunqi Shen,Song Guo 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.1

Numerous deep oil and gas reservoirs have recently been discovered in the Kelasu-Yiqikelike structural belt of the Kuqa Depression in the northern Tarim Basin, north-western China. The sources and accumulation processes of the oil and gas are determined in this study through a series of biomarker geochemical parameter analyses and fluid inclusion analyses, respectively. The geochemical parameters show that the oil of the Kela 2 gas field originated from the Triassic Huangshanjie (T3h) Formation lacustrine source rock and that the oil of the Jurassic reservoirs in the Dibei gas field was sourced from Jurassic coal measures, with some contribution from the T3h source rock. Furthermore, the gas in the Kela 2, Keshen and Dibei gas fields was derived from the Jurassic coal measures. Based on petrographic and fluid inclusion analyses, combined with a reconstruction of the reservoir burial history, timing estimates and charge models of the hydrocarbon accumulation have been obtained. Two stages of oil charging and one stage of gas charging were identified in the Kela 2 gas field. The two stages of oil charging occurred in the middle–late Miocene and in the early Pliocene. The gas charge occurred in the middle–late Pliocene. Additionally, one stage of gas charging occurred in the Keshen gas field in the late Pliocene to Quaternary. In contrast, two hydrocarbon charging stages were identified in the Dibei gas reservoirs, with the first occurring in the early Miocene and the second occurring in the Pliocene.

Could Clinical Pathways Improve the Quality of Care in Patients with Gastrointestinal Cancer? A Meta-analysis

Song, Xu-Ping,Tian, Jin-Hui,Cui, Qi,Zhang, Ting-Ting,Yang, Ke-Hu,Ding, Guo-Wu Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.19

This meta-analysis was performed to assess the implementation effects of clinical pathways in patients with gastrointestinal cancer. A comprehensive search was conducted in the Cochrane Library, PubMed, EMBASE, Web of Science and Chinese Biomedical Literature Database (from inception to May 2014). Selection of studies, assessing risk of bias and extracting data were performed by two reviewers independently. Outcomes were analyzed by fixed-effects and random-effects model meta-analysis and reported as mean difference (MD), standardized mean difference (SMD) and odds ratio (OR) with 95% confidence intervals (CI). The Jadad methodological approach was used to assess the quality of included studies and the meta-analysis was conducted with RevMan 5.1 software. Nine citations (eight trials) involving 642 patients were included. The aggregate results showed that a shorter average length of stay [MD = -4.0; 95% CI (-5.1, -2.8); P < 0.00001] was observed with the clinical pathways as compared with the usual care. A reduction in inpatient expenditure [SMD = -1.5; 95% CI (-2.3, -0.7); P = 0.0001] was also associated with clinical pathways, along with higher patient satisfaction [OR = 4.9; 95% CI (2.2, 10.6); P < 0.0001]. Clinical pathways could improve the quality of care in patients with gastrointestinal cancer, as evidenced by a significant reduction in average length of stay, a decrease in inpatient expenditure and an improvement in patient satisfaction. Therefore, indicators and mechanisms within clinical pathways should be a focus in the future.

Knocking Down Nucleolin Expression Enhances the Radiosensitivity of Non-Small Cell Lung Cancer by Influencing DNA-PKcs Activity

Xu, Jian-Yu,Lu, Shan,Xu, Xiang-Ying,Hu, Song-Liu,Li, Bin,Qi, Rui-Xue,Chen, Lin,Chang, Joe Y. Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Nucleolin (C23) is an important anti-apoptotic protein that is ubiquitously expressed in exponentially growing eukaryotic cells. In order to understand the impact of C23 in radiation therapy, we attempted to investigate the relationship of C23 expression with the radiosensitivity of human non-small cell lung cancer (NSCLC) cells. We investigated the role of C23 in activating the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), which is a critical protein for DNA double-strand breaks (DSBs) repair. As a result, we found that the expression of C23 was negatively correlated with the radiosensitivity of NSCLC cell lines. In vitro clonogenic survival assays revealed that C23 knockdown increased the radiosensitivity of a human lung adenocarcinoma cell line, potentially through the promotion of radiation-induced apoptosis and adjusting the cell cycle to a more radiosensitive stage. Immunofluorescence data revealed an increasing quantity of ${gamma}$-H2AX foci and decreasing radiation-induced DNA damage repair following knockdown of C23. To further clarify the mechanism of C23 in DNA DSBs repair, we detected the expression of DNA-PKcs and C23 proteins in NSCLC cell lines. C23 might participate in DNA DSBs repair for the reason that the expression of DNA-PKcs decreased at 30, 60, 120 and 360 minutes after irradiation in C23 knockdown cells. Especially, the activity of DNA-PKcs phosphorylation sites at the S2056 and T2609 was significantly suppressed. Therefore we concluded that C23 knockdown can inhibit DNA-PKcs phosphorylation activity at the S2056 and T2609 sites, thus reducing the radiation damage repair and increasing the radiosensitivity of NSCLC cells. Taken together, the inhibition of C23 expression was shown to increase the radiosensitivity of NSCLC cells, as implied by the relevance to the notably decreased DNA-PKcs phosphorylation activity at the S2056 and T2609 clusters. Further research on targeted C23 treatment may promote effectiveness of radiotherapy and provide new targets for NSCLC patients.

Non-isothermal Decomposition Kinetics of a New High-energy Organic Potassium Salt: K(DNDZ)

Xu, Kangzhen,Zhao, Fengqi,Song, Jirong,Ren, Xiaolei,Gao, Hongxu,Xu, Siyu,Hu, Rongzu Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.10

A new high-energy organic potassium salt, 2-(dinitromethylene)-1,3-diazepentane potassium salt K(DNDZ), was synthesized by reacting of 2-(dinitromethylene)-1,3-diazepentane (DNDZ) and potassium hydroxide. The thermal behavior and non-isothermal decomposition kinetics of K(DNDZ) were studied with DSC, TG/DTG methods. The kinetic equation is $\frac{d{\alpha}}{dT}$ = $\frac{10^{13.92}}{\beta}$3(1 - $\alpha$[-ln(1 - $\alpha$)]$^{\frac{2}{3}}$ exp(-1.52 ${\times}\;10^5$ / RT). The critical temperature of thermal explosion of K(DNDZ) is $208.63\;{^{\circ}C}$. The specific heat capacity of K(DNDZ) was determined with a micro-DSC method, and the molar heat capacity is 224.63 J $mol^{-1}\;K^{-1}$ at 298.15 K. Adiabatic time-to-explosion of K(DNDZ) obtained is 157.96 s.

HIF-1α and GLUT1 Gene Expression is Associated with Chemoresistance of Acute Myeloid Leukemia

Song, Kui,Li, Min,Xu, Xiao-Jun,Xuan, Li,Huang, Gui-Nian,Song, Xiao-Ling,Liu, Qi-Fa Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.4

Aims: Much evidence suggests that increased glucose metabolism in tumor cells might contribute to the development of acquired chemoresistance. However, the molecular mechanisms are not fully clear. Therefore, we investigated a possible correlation of mRNA expression of HIF-$1{\alpha}$ and GLUT1 with chemoresistance in acute myeloid leukemia (AML). Methods: Bone marrow samples were obtained from newly diagnosed and relapsed AML (M3 exclusion) cases. RNA interference with short hairpin RNA (shRNA) was used to stably silence GLUT1 or HIF-$1{\alpha}$ gene expression in an AML cell line and HIF-$1{\alpha}$ and GLUT1 mRNA expression was measured by real-time quantitative polymerase chain reaction assay (qPCR). Results: High levels of HIF-$1{\alpha}$ and GLUT1 were associated with poor responsiveness to chemotherapy in AML. Down-regulation of the expression of GLUT1 by RNA interference obviously sensitized drug-resistant HL-60/ADR cells to adriamycin (ADR) in vitro, comparable with RNA interference for the HIF-$1{\alpha}$ gene. Conclusions: Our data revealed that over-expression of HIF-$1{\alpha}$ and GLUT1 might play a role in the chemoresistance of AML. GLUT1 might be a potential target to reverse such drug resistance.

Development of Low-Cost Deformation-based Micro Surface Texturing System for Friction Reduction

Song Xu,Sam Oh Jin An,Danno Atsushi,Sylvie Castagne 한국정밀공학회 2016 International Journal of Precision Engineering and Vol.17 No.8

Surface texturing as a means for enhancing tribological properties of mechanical components has been under intensive investigation over the last two decades. Many methods have been proposed to create surface texture of various patterns and geometries. However, among all these methods, deformation-based micro-surface texturing is least studied. It has many advantages over other methods that could lead to immediate industry application, including high productivity, high geometry fidelity and low cost. In the current work, a simple but effective incremental micro embossing system based on a commercially available press has been developed to create micro surface textures of various shapes and depths with accuracy up to 5 μm. The friction coefficients of the textured surfaces have been tested at different loadings and speeds with various lubricants to demonstrate their friction reduction capability. It has been observed that at high speed conditions, the friction reduction is achieved by the hydrodynamic lift. Interestingly, at the low speed conditions, the micro-surface texture is still capable of reducing the friction, thanks to its lubricant retention and debris entrapment capability. A micro surface textured mechanical face seal demonstrator has been built to further evaluate the micro surface texture created by incremental embossing method. A reduction of 20% in torque friction has been consistently achieved, which is on a par with that of the laser surface texturing method.

Cyclooxygenase-2 Promoter 765C Increase of Digestive Tract Cancer Risk in the Chinese Population: a Meta-analysis

Xu, Yan-Song,Zhao, Bo,Long, Chen-Yan,Li, Hui,Lu, Xing,Liu, Gang,Tang, Xiao-Zhun,Tang, Wei-Zhong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.11

Background: To evaluate relationship between the cyclooxygenase-2 promoter 765G/C polymorphism and digestive cancer risk in China. Materials and Methods: A literature search through February 2014 was performed using PubMed, Chinese Biomedical Literature Database (CBM) and China National Knowledge Infrastructure (CNKI) databases, and a meta-analysis was performed with RevMan 5.2 software for odds ratios and 95%CIs. Results: In total, 9 articles with 3,263 cases and 4,858 controls were included in this meta-analysis. The pooled OR (95%CIs) in the co-dominant model (GC vs GG) was 1.56 [1.19, 2.06], and in the dominant model ((CC+GC) vs GG), the pooled OR was 1.59 [1.21, 2.09] in overall cancers. In the subgroup analysis, stratified by cancer type, significant associations were found that the-765C allele had increased pancreatic cancer and gastric risk. No significant liver cancer and colorectal cancer risk of COX-2 -765G/C polymorphism was found. Conclusions: These findings suggest that COX-2-765*C is related to cancer susceptibility and may increase gastric and pancreatic cancer risk.

Numerical simulation of pressure relief in hard coal seam by water jet cutting

Song, Dazhao,Wang, Enyuan,Xu, Jiankun,Liu, Xiaofei,Shen, Rongxi,Xu, Wenquan Techno-Press 2015 Geomechanics & engineering Vol.8 No.4

The applications of water jet cutting (WJC) in coal mine have progressed slowly. In this paper, we analyzed the possibility and reasonableness of WJC application to pressure relief in hard coal seam, simulated the distributive characteristics of stress and energy fields suffered by hard coal roadway wallrock and the internal relationships of the fields to the instability due to WJC (including horizontal radial slot and vertical annular slot) on roadway wallrock. The results showed that: (1) WJC can unload hard coal seam effectively by inducing stress release and energy dissipation in coal mass near its slots; its annular slots also can block or weaken stress and energy transfer in coal mass; (2) the two slots may cause "the beam structure" and "the small pillar skeleton", and "the layered energy reservoir structure", respectively, which lead to the increase in stress concentration and energy accumulation in coal element mass near the slots; (3) the reasonable design and optimization of slots' positions and their combination not only can significantly reduce the scope of stress concentration and energy accumulation, but also destroy coal mass structure on a larger scale to force stress to transfer deeper coal mass.

Theoretical Study on the Point Defects in N-Doped Anatase TiO2

Song-You Wang,Fei Pei,Song Wu,Gang Wang,Ming Xu,Liang-Yao Chen,Yu Jia 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.4

In this work, first-principles calculations for the electronic and the optical properties of titanium dioxide (TiO2) with point defects are performed by using a plane wave pseudopotential method in the framework of the density functional theory and the generalized gradient approximation. The point defects, substitutional and interstitial nitrogen, in anatase TiO2 are investigated to understand the origin of the visible-light sensitivity of nitrogen (N)-doped TiO2. The results show that bands originating from substitutional N 2p states appear above the top of the valence band. These states tend to be delocalized and to mix with the valence band as the nitrogen concentration is increased. The optical absorption in the range between 400 and 700 nm is enhanced by the substitutional N impurities. The eect of interstitial N on the electronic and the optical properties of TiO2 depends on the interaction between the nitrogen dopants and the surrounding oxygen. The bonding between N and O introduces a series of localized occupied states under and above the upper valence band, and the electron transitions from these states improve the visible-light absorption of TiO2.