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.

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.

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.

연변 조선족 무형문화유산의 전승실태와 발전방안연구

Song, Xu-ri(宋旭日),Piao, Jin-hai(朴今海) 한국외국어대학교 역사문화연구소 2014 역사문화연구 Vol.51 No.-

중국의 연변조선족자치주는 중국내 조선족의 고향으로 자리 잡고 있다. 그것은 단지 연변이 지정학적으로 한반도와 잇대어 있고 또한 조선족의 가장 큰 집거구라는 요인 외에도 더 중요하게는 이곳에 조선족의 언어, 풍속, 가무, 예의 등 전통문화가 살아 숨 쉬고 있는 민족적 정서 때문이다. 19세기 말부터 시작된 이민으로부터 오늘의 중국의 일개 소수민족으로 자리매김하기까지의 장장 한 세기반의 역사의 흐름 속에서 연변의 조선족은 두만강 북안을 중심으로 한 전통적인 거주지역과 농경문화를 바탕으로 한반도고유의 전통문화를 비교적 완벽하게 보존하고 있을 뿐만 아니라 중국 사회문화와의 접변 속에서 그들 나름대로의 문화를 창출하면서 그 속에서 민족공동체의 연대와 결속을 다져왔다. 연변으로 이주한 이주민의 절대 대부분이 땅을 찾아 한반도를 떠난 농민층으로, 그들이 생산의 주체였고 놀이의 주체였다. 따라서 그들 중에서 생성되고 전승된 문화는 주로 생산문화와 공동체문화로, 농경문화의 색채가 비교적 짙다. 또한 한민족의 디아스포라이면서도 중국의 국민이라는 특정된 신분으로 그들의 문화에는 한반도문화의 유전자가 깊이 낙인 되어 있을 뿐만 아니라 한반도와 다른 나름대로의 새로운 특징들이 생성되었다. 이와 같은 이중적 혹은 복합적 문화성격 및 짙은 민족적 색채로 조선족의 무형문화는 연변지역은 물론, 길림성 심지어는 전국적으로 각광을 받게 되었으며 특히 중국의 무형문화유산발굴을 계기로 세계급의 무형문화유산 1개, 국가급 무형문화유산 16개, 성급 무형문화유산 58개를 보유함으로써 문화민족으로서의 이름을 만방에 떨쳤다. 그러나 중국의 개혁개방 후 급속한 산업화 및 조선족 인구의 초국적 이동으로 전통적 거주지가 위축되고 공동화되면서 많은 전통적인 문화유산, 특히는 무형문화유산이 소실되고 그와 더불어 민족적 정체성도 곤혹을 겪고 있는 게 사실이다. 문화는 민족의 아이덴티티와 그 시대의 정체성을 가장 많이 내포하고 또 표상이라 할 수 있다. 문화가 없는 민족은 영혼이 없는 민족과 다름없다. 조선족의 민족정체성을 찾는 일로 가장 우선 되어야 하는 것이 바로 전통문화유산의 전승보존과 활성화를 통한 문화의 자각이며 특히 전통문화 중에서도 한번 소실되면 재생이 불가능한 무형문화유산의 보존과 전승이 절실하다. 정부차원에서 조선족 무형문화유산의 보호와 전승을 위한 제도적, 정책적 장치, 사회전면에 걸쳐 현대문명과 다문화시대에 맞는 다양한 계승방안의 개발과 재창조, 대중의 참여를 끌어낼 수 있는 방안 및 한반도와의 협력방안 등이 모색되어야 한다. Connected with the Korean Peninsula, Yanbian Korean Autonomous Prefecture is the largest community of Korean Chinese in China. What is more to the point, this is the place where carries the Korean Chinese traditional culture including language, custom, songs, dances and rituals. In the long course of history from the 19thcentury to present, Korean migrants who left home country became one of the 56 minority nationalities in China. Centered in the north of Tumen River and based on traditional farming culture, Korean Chinese of Yanbian has not only kept quite intact intrinsic culture of the Korean Peninsula, but also has formed his own unique culture in the process of contact with Chinese society and culture, which go further strengthening the tie and belongings of its national community. With the identity of diaspora of Korean nation and Chinese nationality, the culture of Korean Chinese is branded with Korean Peninsula and Chinese new characteristics. This kind of dual or multiple cultural natures make the non-material cultural heritages of Korean Chinese grab the attention not only in Yanbian Area, but also in Jilin Province, and even nationwide. Grasping the opportunity of China's non-material cultural heritages development, Yanbian Area has possessed one world-class non-material cultural heritage, six nation-class non-material cultural heritages, fifty eight provincial-level non-material cultural heritages. However, with the rapid industrialization and large-scale trans-national migration by Korean Chinese, traditional settlement has begun to shrink and hollow out, many traditional cultural heritages especially non-material cultural heritages have begun to disappear, by which national identity of Korean Chinese disordered and confused. Culture is the connotation and representation of national identity. A nation without culture is one without soul. The way out to firm the national identity is to preserve, protect and activate the traditional heritage, especially the non-material cultural heritage, which once disappeared, could not regenerate.

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.

Synthesis and Characterization of pH and Temperature Sensitive Hydrogel Based on Poly(N-isopropylacrylamide), Poly(ε-caprolactone), Methylacrylic Acid, and Methoxyl Poly(ethylene glycol)

Xu Xu,Jia Song,Ke Wang,YingChun Gu,Feng Luo,XiaoHai Tang,Ping Xie,ZhiYong Qian 한국고분자학회 2013 Macromolecular Research Vol.21 No.8

In this paper, a novel biodegradable and pH/thermo-sensitive hydrogel based on poly(ε-caprolactone),methoxyl poly(ethylene glycol), methylacrylic acid and N-isopropylacrylamide was prepared by UV-initiated free radical polymerization. The hydrogels were characterized by Fourier transforms infrared ray. The thermal responsibility was investigated with the help of differential scanning calorimetry. Swelling behavior in aqueous medium with different pH value was studied in detail. When the pH value of the aqueous medium was increased from 1.2 to 7.2,the swelling ratio of the hydrogels increased accordingly. The morphology was observed by scanning electron microscopy, and the hydrolytic degradation behavior in different aqueous media (pH 1.2 and pH 7.2) was also investigated in detail. The prepared biodegradable pH/thermo-sensitive hydrogel based on poly(ε-caprolactone), methoxyl poly(ethylene glycol), methylacrylic acid and N-isopropylacrylamide hold great promise in the development of a smart drug delivery system.

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.

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.