Performance analysis and experimental verification of hydraulic driven axial flow pumps

Zhiting Tong,Ye Yuan,Chao Zhang,Zhimin Zhang,Yue Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.6

To investigate axial flow pumps’ performance characteristics, NUMECA software is selected to perform numerical simulation at four rotating speeds (1380, 1840, 2300, and 2530 r/min) based on the Spalart-Allmaras turbulence model. The relationship curves of flowhead and flow-pump efficiency, static pressure distribution on blade surfaces, velocity variation near the hub, and total pressure distribution at different blade heights are obtained. Results indicate that with the improvement of the rotating speed, the curves of the head and the efficiency rise and shift to the right, the pressure difference on both sides of the blade ascends, and the moment acting on the blade induced by the water flow also increases, resulting in higher head. At the rated speed of 2300 r/min, the pressure difference between the pressure side and the suction side at low flowrates increases, the minimum pressure is lower, and the anticavitation performance decreases, whereas the velocity distribution near the hub is the same at different flowrates. Moreover, the velocity is lower near the hub’s leading edge, and no influence is observed. To guarantee the reliability and comparability, experimental data are contrasted with the simulated results at the speed of 2182 r/min. At the near design condition (Q = 534.4-567 m 3 /h), the relative deviation of efficiency and head is less than 4.5 %, which is a small gap. These conclusions provide valuable reference for axial flow pumps to operate under variable speed conditions.

A Comparative Study of National Intangible Cultural Heritage between China and the ROK based on Traditional Dance Items

Zhiting Zhang KOREA INSTITUTE FOR HUMANITIES AND SOCIAL SCIENCES 2023 Journal of Arts and Cultural Studies(ACS) Vol.2 No.2

Background: There is a long history of the safeguarding of cultural heritage in East Asian countries. Since the 20th century, a growing number of countries have begun to highlight the safeguarding and inheritance of intangible cultural heritage, among which China and the Republic of Korea (ROK), the two East Asian countries, have also actively participated in it. Objective: This paper compares and discusses measures taken by China and the ROK in the safeguarding of intangible cultural heritage by analyzing relevant content of the intangible cultural heritage safeguarding and inheritance system between the two countries in its attempt to put forward reasonable suggestions for the safeguarding and inheritance of China’s intangible culture heritages in the future while drawing lessons from relatively complete safeguarding and inheritance measures of the ROK and taking the national conditions of China into consideration. Methods: This paper sums up relevant measures taken by China and ROK in the protection of intangible cultural heritage through literature review and draws further a conclusion from comparative analysis. Results: The ROK, also as an Asian country, has established a systematic management scheme for the safeguarding and inheritance of intangible cultural heritage earlier than its neighbor China in the region. Despite a late start, China has also established a relatively complete scheme of systematic safeguarding and inheritance of intangible cultural heritage in a short period of time. The sound practices of safeguarding intangible cultural heritage in the ROK can shed some light on China. Conclusions: China can draw on related measures of the ROK for the safeguarding and inheritance of intangible cultural heritage in the future. Constructive suggestions can be proposed from the aspects of strengthening school education communication, enhancing financial support, promoting on-stage presentation, improving the standardization of festivals or celebrations, and adding more museums for inheritance and education.

ANNULUS CRITERIA FOR OSCILLATION OF SECOND ORDER DAMPED ELLIPTIC EQUATIONS

Zhiting Xu 대한수학회 2010 대한수학회지 Vol.47 No.6

Some annulus oscillation criteria are established for the second order damped elliptic differential equation [수식]under quite general assumption that they are based on the information only on a sequence of annuluses of Ω­(r0) rather than on the whole exterior domain ­Ω(r0). Our results are extensions of those due to Kong for ordinary differential equations. In particular, the results obtained here can be applied to the extreme case such as Ω­(r0) c(x)dx = −∞.

Robustness Management with Data Quality in Information Systems

Zhiting Song,Yanming Sun 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.9

The data quality in information systems affects system robustness significantly. Although a large body of research focuses on the issue of data quality, seldom has literature been done to develop effective control policies to manage system robustness associated with data errors. A process-oriented methodology is proposed to manage system robustness measured by performance, control cost and control time, which is achieved through establishing formal model of information systems and mathematical optimization models of system robustness. The proposed methodology captures how structural and functional characteristics of tasks affect system robustness and finds the optimal control policies, which facilitates the robustness-based design and management of information systems respectively. The methodology is illustrated in the case study.

Oscillation of Second Order Nonlinear Elliptic Differential Equations

XU, ZHITING 대한수학회 2006 Kyungpook mathematical journal Vol.46 No.1

By using general means, some oscillation criteria for second order nonlinear elliptic differential equation with damping ◁수식 삽입▷(원문을 참조하세요) are obtained. These criteria are of a high degree of generality and extend the oscillation theorems for second order linear ordinary differential equations due to Kamenev, Philos and Wong.

Oscillation of Second Order Nonlinear Elliptic Differential Equations

Xu, Zhiting Department of Mathematics 2006 Kyungpook mathematical journal Vol.46 No.1

By using general means, some oscillation criteria for second order nonlinear elliptic differential equation with damping $$\sum_{i,j=1}^{N}D_i[a_{ij}(x)D_iy]+\sum_{i=1}^{N}b_i(x)D_iy+p(x)f(y)=0$$ are obtained. These criteria are of a high degree of generality and extend the oscillation theorems for second order linear ordinary differential equations due to Kamenev, Philos and Wong.

A Study on the Development of Dance Movements of ‘Yuan heng li zhen’ Circular Thought in <Zhouyi>

张植婷(Zhiting ZHANG) Korea Institute for Humanities and Social Sciences 2023 Journal of Global Arts Studies (JGAS) Vol.1 No.1

【背景】《周易》对中国和东方哲学都有重要的影响,是中国哲学思想的源头。“元亨利贞”的循环思想作为《周易》中最重要的思想之一直在指导着我们的生活,为我们揭示了事物发展的本质规律。【目的】研究者通过理解和再分析“元亨利贞”的循环思想,尝试开发符合其内涵的舞蹈动作。【方法】本研究首先通过综述的方法对《周易》的背景,及其中“元亨利贞”的循环思想进行了探究和整理。并且查找了与循环思想的舞蹈创作相关的艺术视频、及图片。第二,研究者对《周易》中“元亨利贞”的循环思想进行了个人的分析理解,且根据该思想开发了相应的舞蹈动作。【结果】通过肢体语言的探索,研究者实现了对“元亨利贞”中形而上的循环思想的舞蹈动作传达,并对其进行了分析。通过舞蹈动作的编排,呈现了事物的原始、发展、矛盾、循环四个阶段形象化的表现。【结论】本研究揭示了东方思想理论和舞蹈动作开发的相关过程,拓展了舞蹈艺术的运用。通过将东方思想在舞蹈动作中以形象化、具体化的方式展现出来,实现了艺术与人文的融合。并对未来有关思想及哲学层面的舞蹈艺术的具像化展现提出展望。 [Background] <Zhouyi> has an important influence on both Chinese and Eastern philosophy, and is the source of Chinese philosophical thoughts. As one of the most important thoughts in <Zhouyi>, ‘Yuan heng ly zhen's circular thought has been guiding our life and revealing the essential law of the development of things for us. [Objective]By understanding and reanalyzing the circular thought of ‘Yuan heng li zhen’, researcher try to develop dance movements that conform to its connotation. [Method] Firstly, this study explored and sorted out the background of <Zhouyi> and the circular thought of ‘Yuan heng li zhen’ in <Zhouyi> by review. In addition, the researchers looked for artistic videos and pictures associated with the creation of circular dance. Second, the researcher makes a personal analysis and understanding of the circular thought of ‘Yuan heng li zhen’ in <Zhouyi>, and develops corresponding dance movements.[Results]Through the exploration of body language, the researchers realized the communication of the metaphysical circular idea ‘Yuan heng li zhen’ and the dance movement , and analyzed it. Through the choreography of dance movements, it presents the four stages of the original, development, contradiction and circulation of things.[Conclusion]This study reveals the related process of Oriental thought theory and dance movement development, and expands the application of dance art. The integration of art and humanity is realized by visualizing and concretizing Oriental thoughts in dance movements. It also puts forward the prospect of the figurative display of the dance art on the ideological and philosophical level in future.

ANNULUS CRITERIA FOR OSCILLATION OF SECOND ORDER DAMPED ELLIPTIC EQUATIONS

Xu, Zhiting Korean Mathematical Society 2010 대한수학회지 Vol.47 No.6

Some annulus oscillation criteria are established for the second order damped elliptic differential equation $$\sum\limits_{i,j=1}^N D_i[a_{ij}(x)D_jy]+\sum\limits_{i=1}^Nb_i(x)D_iy+C(x,y)=0$$ under quite general assumption that they are based on the information only on a sequence of annuluses of $\Omega(r_0)$ rather than on the whole exterior domain $\Omega(r_0)$. Our results are extensions of those due to Kong for ordinary differential equations. In particular, the results obtained here can be applied to the extreme case such as ${\int}_{\Omega(r0)}c(x)dx=-\infty$.

An implementation of distributed and HTTP-based geological petroleum data web service with RESTful architecture

Shijie Peng,Zhiting Zhang,Chonglong Wu,Gang Liu 한국자원공학회 2017 Geosystem engineering Vol.20 No.6

It researches how to build a distributed data service platform based on REST architecture in the digital oilfield. In oil enterprise, the data are scattered in the isolated system among various department. Due to the management issue, all the database and interface standards and technologies of departmental system are incompatible to each other. With the continuous expansion of exploration and research, the demand for enterprise data integration platform is tremendous increased. In this paper, we propose a data integration based on REST style data interface. It focuses on the REST interface with HATEOAS constraint and the distributed transaction model driven by REST interface. The data integration platform specifically has solved the sharing and integration issues as well as the transactional problem across heterogeneous system in the oilfield enterprise.

Oscillation of Certain Second Order Damped Quasilinear Elliptic Equations via the Weighted Averages

XIA, YONG,XU, ZHITING 대한수학회 2007 Kyungpook mathematical journal Vol.47 No.2

By using the weighted averaging techniques, we establish oscillation criteria for the second order damped quasilinear elliptic differential equation □D_(i)(a_(ij)(x)||D_(y)||^(p-2)D_(j)y+<b(x),||D_(y)||^(p-2)D_(y)>+c(x)f(y) = 0, p>1. The obtained theorems include and improve some existing ones for the undamped half-linear partial differential equation and the semilinear elliptic equation.