Structure modification and numerical study of the moisture-separation performance of special crossunder pipe separators for nuclear power steam turbines

Wang Xinjun,Cheng Peng,Xie Jinwei,Zhou Zijie 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.8

The present paper investigated the enhancement of moisture-separation efficiency for ordinary special crossunder pipe separators(SCRUPSs) and proposed three structure-modified separators (combined separator, Z-shaped SCRUPSs, and spiral-type SCRUPSs). Deposition mechanisms for droplets with different sizes were considered using commercial CFD flow solver. Results show that threestructuremodified separators can increase droplet deposition rate to varying degrees. Regarding flow losses, spiral-type SCRUPSs causethe highest increase, with a total pressure loss coefficient of 231%, although it has the best deposition rate improvement. Among the threestructure-modified separators, "Z" shape separator has the best separation performance because of its higher moisture-separation efficiencyand lower total pressure loss efficiency. Results could provide theoretical basis for research on and development of this new typeof moisture separator.

Numerical analysis of transient pressure variation in the condenser of a nuclear power station

Xinjun Wang,Zijie Zhou,Zhao Song,Qiankui Lu,Jiafu Li 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.2

To research the characteristics of the transient variation of pressure in a nuclear power station condenser under accident condition, a mathematical model was established which simulated the cycling cooling water, heat transfer and pressure in the condenser. The calculation program of transient variation characteristics was established in Fortran language. The pump’s parameter, cooling line’s organization, check valve’s feature and the parameter of siphonic water-collecting well are involved in the cooling water flow’s mathematical model. The initial conditions of control volume are determined by the steady state of the condenser. The transient characteristics of a 1000 MW nuclear power station’s condenser and cooling water system were examined. The results show that at the condition of plant-powersuspension of pump, the cooling water flow rate decreases rapidly and refluxes, then fluctuates to 0. The variation of heat transfer coefficient in the condenser has three stages: at start it decreases sharply, then increases and decreases, and keeps constant in the end. Under three conditions (design, water and summer), the condenser pressure goes up in fluctuation. The time intervals between condenser’s pressure signals under three conditions are about 26.4 s, which can fulfill the requirement for safe operation of nuclear power station.

Active control of amplitude and phase of high-power RF systems in EAST ICRF heating experiments

Zhu Guanghui,Liu Lunan,Mao Yuzhou,Zhang Xinjun,Guo Yaoyao,Ai Lin,Jiang Runhao,Qin Chengming,Zhang Wei,Yang Hua,Yuan Shuai,Wang Lei,Ju Songqing,Wang Yongsheng,Sun Xuan,Yang Zhida,Wang Jinxin,Cheng Yan 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2

The EAST ICRF system operating space has been extended in power and phase control with a low-level RF system for the new double-strap antenna. Then the multi-step power and periodic phase scanning experiment were conducted in L-mode plasma, respectively. In the power scanning experiment, the stored energy, radiation power, plasma impedance and the antenna's temperature all have positive responses during the short ramp-ups of PL;ICRF. The core ion temperature increased from 1 keV to 1.5 keV and the core heating area expanded from jZj 5 cmto jZj 10 cm during the injection of ICRF waves. In the phasing scanning experiment, in addition to the same conclusions as the previous relatively phasing scanning experiment, the superposition effect of the fluctuation of stored energy, radiation power and neutron yield caused by phasing change with dual antenna, resulting in the amplitude and phase shift, was also observed. The active control of RF output facilitates the precise control of plasma profiles and greatly benefits future experimental exploration.

The Effect of CTAB on the Citrate Sol-gel Process for the Synthesis of Sodium Beta-Alumina Nano-Powders

Wang, Zaihua,Li, Xinjun,Feng, Ziping Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.4

Sodium beta-alumina (SBA) nano-powders were synthesized by the citrate sol-gel process, and the effects of the cationic surfactant n-cetyltrimethylammonium bromide surfactant (CTAB) were investigated. The structure and morphology of the nano-powders were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques, respectively. The effects of CTAB on the citrate sol-gel process and the SBA formation were investigated by thermo gravimetric/differential thermal analysis (TG/DTA) and Fourier transform infrared spectroscopy (FTIR). The conductivity of ceramic pellets of SBA was measured by electrochemical impedance spectroscopy (EIS). The results showed that the CTAB inhibited the agglomeration of SBA powders effectively and consequently decreased the crystallization temperature of SBA, about $150^{\circ}C$ lower than that of the sample without CTAB. The measured conductivity of SBA was $1.21{\times}10^{-2}S{\cdot}cm^{-1}$ at $300^{\circ}C$.

Research on Capability Assessment of IS Outsourcing Service Providers

Xinjun Li,Junyan Wang 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.6

IS outsourcing services have developed into a major and continuously growing IS services business. Although there is a wealth of academic literature examining information systems (IS) outsourcing, there is little academic literature that addresses the current outsourcing problem that most firms facing, which is how to assess IS outsourcing service providers’ capability. Given multiattribute nature of IS outsourcing service providers’ capability assessment, this paper argues that thirteen capability criteria should be considered for assessments, and proposes the PROMETHEE as aids in assessing IS outsourcing service providers’ capability decisions, together with changing weights for a sensitivity analysis. It shows by means of an application that the presented method is very well suited as a tool for the IS outsourcing service providers’ capability assessment.

The Effect of CTAB on the Citrate Sol-gel Process for the Synthesis of Sodium Beta-Alumina Nano-Powders

Zaihua Wang,Xinjun Li,Ziping Feng 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.4

Sodium beta-alumina (SBA) nano-powders were synthesized by the citrate sol-gel process, and the effects of the cationic surfactant n-cetyltrimethylammonium bromide surfactant (CTAB) were investigated. The structure and morphology of the nano-powders were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques, respectively. The effects of CTAB on the citrate sol-gel process and the SBA formation were investigated by thermo gravimetric/differential thermal analysis (TG/DTA) and Fourier transform infrared spectroscopy (FTIR). The conductivity of ceramic pellets of SBA was measured by electrochemical impedance spectroscopy (EIS). The results showed that the CTAB inhibited the agglomeration of SBA powders effectively and consequently decreased the crystallization temperature of SBA, about 150 °C lower than that of the sample without CTAB. The measured conductivity of SBA was 1.21 × 10^(−2) S·cm^(−1) at 300 °C.

Research on Heterogeneous Data resource Management Model in Cloud Environment

Tao Sun,Xinjun Wang 보안공학연구지원센터 2013 International Journal of Database Theory and Appli Vol.6 No.5

Research of Data Security Model in Cloud Computing Platform for SMEs

Tao Sun,Xinjun Wang 보안공학연구지원센터 2013 International Journal of Security and Its Applicat Vol.7 No.6

Exploiting User Behavior Changes in Privacy Disclosure by Modified Clustering Technique

Hongchen Wu,Xinjun Wang,Zhaohui Peng,Qingzhong Li 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.5

The analysis of user behaviors has been an important subject in recommending research recently. This paper proposes a modified clustering technique, showing that users privacy disclosure may change when they are answering the information requests, and we argues that their attitudes, including risk, useful, appropriate, played an important role behind those changes. We presented the new data structure in our dataset that would be loaded to experiment, e.g. personal information requests, users’ answers to those requests, and most importantly, users cluster and attitude for later analysis. Our modified clustering technique would not only locate users privacy disclosure change by comparing the results from learning their past disclosure behaviors and from learning their current disclosures, but also exploit the relationship between the inconsistence in those two results and their attitudes. The data containing users’ answers to a questionnaire with personal information requests was integrated to analyze their disclosure behaviors and attitude with the proposed clustering technique. We indeed find some interesting connections between their privacy disclosure change and attitudes, and the exploration of this paper could benefit to any researchers and online community owners who focusing on user-centered strategies and personal-information-requesting issues.

Study on In-Situ Nucleation, Growth Kinetics and Crystallographic Structure of Acicular Ferrite in X100 Pipeline Steel Welds

Xiaonan Qi,Xiaonan Wang,Xinjun Shen,Pengcheng Huan,Zhenguang Liu,Hongshuang Di 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.9

Acicular ferrite has appeared in various low carbon microalloyed steel welds (e.g., laser-arc hybrid welds) due to its highgrain boundary density and toughness. However, the transformation kinetics and crystallographic structure characteristics ofacicular ferrite in laser-arc hybrid welds are still unclear. In this paper, the nucleation and growth kinetics of acicular ferritein laser-metal active gas hybrid welds with different cooling rates (1–150 K/s) were investigated and their crystallographiccharacteristics were revealed from the perspective of variant. The result showed that acicular ferrite can nucleate at all thetest cooling rates in weld metal, and the microstructure coexisting with acicular ferrite changes from polygonal ferrite andgranular bainite with a low cooling rate to lath martensite with a high cooling rate. As the cooling rate increases, the phasetransformation temperature of acicular ferrite decreased, and the phase transformation mode changed from partitioninglocal equilibrium to negligible partitioning local equilibrium. The variety of the phase transformation mode and the higherphase transformation driving force led to an increase in the growth rate of acicular ferrite. Compared with the bainite andmartensite in the base metal, the acicular ferrite had the characteristics of light variant selection, uniformly distributedoperating factor and small variant size, which resulted in high-density effective grain boundaries. To obtain more acicularferrite, the cooling rate should be increased as much as possible on the premise that the phase transformation terminationtemperature was higher than the Ms.