http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Power Cable Ampacity and Influential Factors Analysis under Operation
( Qiang Tong ),( Jianping Qi ),( Yanling Wang ),( Likai Liang ),( Xiangxing Meng ),( Qiang Zhang ) 한국정보처리학회 2018 Journal of information processing systems Vol.14 No.5
With the increasing of urban electricity demand, making the most use of the power cable carrying capacity has become an important task in power grid system. Contrary to the rated ampacity obtained under extremely conservative conditions, this paper presents the various steady value of cable ampacity by using the changing surrounding parameters under operation, which is based on cable ampacity calculation equation under the IEC-60287 standard. To some degree, the cable ampacity analysis of actual surroundings improves the transmission capacity of cables. This paper reveals the factors that influence cable ampacity such as insulating layer thickness, allowable long-term conductor temperature, the ambient temperature, soil thermal resistance coefficient, and so on, then gives the class of the influence of these parameters on the ampacity, which plays a great role in accurately calculating the real-time ampacity and improving the utilization rate of cable in the complex external environment condition. Furthermore, the transient thermal rating of the cable is analyzed in this paper, and temperature variation of the conductor under different overload conditions is discussed, which provides effective information for the operation and control of the system.
Failure Analysis on Pressure Leakage of FRP
Guoquan Qi,Dongtao Qi,Qiang Bai,Houbu Li,Bin Wei,Nan Ding,Dongna Zhang,Xiaodong Shao 한국섬유공학회 2019 Fibers and polymers Vol.20 No.3
The fiberglass reinforced plastic (FRP) pipe used in the ground gathering system of an oil field occurred leakagefailure during the pressure test on site after installation. Investigations were performed to identify the most probable causes of the pipe failures. Take three types of specimens for the study, which is the leak position of failure line; the non-leaked position of failure line and the standby pipeline after insulation. The study was conducted by reviewing the background of the incident, visual physical inspection, mechanical property test and finite element analysis. The reason for the failure of this batch pipe is that, a large number of circumferential cracks appear on the outer wall of the pipe under the external force dominated by the bending stress, which reduced the overall internal pressure performance and caused the leakage failure of the pipe line. The leakage failure during the pressure test on site is mostly located in the transition zone of the pipe body to joint, which is due to the discontinuity of wall thickness and uneven material.
Power Cable Ampacity and Influential Factors Analysis under Operation
Tong, Qiang,Qi, Jianping,Wang, Yanling,Liang, Likai,Meng, Xiangxing,Zhang, Qiang Korea Information Processing Society 2018 Journal of information processing systems Vol.14 No.5
With the increasing of urban electricity demand, making the most use of the power cable carrying capacity has become an important task in power grid system. Contrary to the rated ampacity obtained under extremely conservative conditions, this paper presents the various steady value of cable ampacity by using the changing surrounding parameters under operation, which is based on cable ampacity calculation equation under the IEC-60287 standard. To some degree, the cable ampacity analysis of actual surroundings improves the transmission capacity of cables. This paper reveals the factors that influence cable ampacity such as insulating layer thickness, allowable long-term conductor temperature, the ambient temperature, soil thermal resistance coefficient, and so on, then gives the class of the influence of these parameters on the ampacity, which plays a great role in accurately calculating the real-time ampacity and improving the utilization rate of cable in the complex external environment condition. Furthermore, the transient thermal rating of the cable is analyzed in this paper, and temperature variation of the conductor under different overload conditions is discussed, which provides effective information for the operation and control of the system.
Bing-qiang Zhang,Qi-wen Chen,Feng-wen Lai,Fu-Quan Chen,Bin-bin Qi 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.1
A gap formation underneath pipelines could be observed during tunneling beneath existing buried pipelines, thus altering the pipeline-soil interaction behavior. However, the most existing analytical approaches typically do a full contact assumption for brevity. For such purpose, we aim to present an analytical approach coupling the effect of gap formation underneath pipelines by considering the buried pipeline as an Euler-Bernoulli beam on tensionless foundation. The pipeline can be divided into three segments according to pipeline-soil interaction behavior, and then the bending behaviors of each segment are formulated. The deflection and bending moment of the pipeline caused by tunnelling underneath from the proposed approach are compared and validated with centrifuge testing data and existing analytical solutions. The effects of pipeline-soil stiffness ratio, pipeline buried depth, tunnel buried depth, tunneling induced volume loss, and tunnel-pipeline intersection angle on the pipeline responses are further discussed. The results indicate that gap formation underneath pipeline can be observed indeed for shallowly buried pipeline and/or larger pipeline-soil stiffness ratio. The proposed analytical approach provides a theoretical guideline to predict the responses of existing pipelines to tunnelling underneath.
QI-HUI SHEN,YAN LIU,XI YU,XIAO-YANG LIU,MING-QIANG ZOU,JIN-FENG LI,JIAN-GUANG ZHOU 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2012 NANO Vol.7 No.6
II?VI Semiconductor nanocrystals (NCs) with tunable visible emission, such as CdS, CdSe and CdTe, were synthesized in aqueous solution using thiols as capping molecules. Hydrazine was found to promote the growth of NCs through a special mechanism. In only a few hours, the synthesis process was completed at room temperature. Under moderate conditions, the capping molecules not only changed the growth rate of NCs simply by varying the concentration, but also altered the spectral properties of NCs. The capping molecules with amino groups were propitious to the growth of CdS NCs, whereas the kinetic growth of CdS NCs was more a®ected by the surface passivation e±ciency of NCs than by steric hindrance in the system. The fastest growth of the CdS NCs was achieved when glutathione was used as a capping molecule, while the emission of CdS and CdSe NCs were shown to remain steady and tunable using the same capping molecule. The growth rate of 3-mercaptopropionic acid-capped CdS and CdSe NCs slowed down signi¯-cantly, while CdTe NCs were obtained with excellent emission properties when capped with the same molecule. Furthermore, our approach will also be useful for the study of the kinetic growth of NCs in aqueous solution.
A Noninjection Reaction Route to CuInSe2 Nanocrystals with Triethanolamine as the Complexing Agent
Qi-Yi Zhang,Wen-Long Liu,Meng-Qiang Wu,Ru-Chao Zhou,Li-Dan Yan,Shu-Ren Zhang 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.12
The chalcopyrite-type CuInSe_2 is a remarkable material for thin film solar cells owing to its electronic structure and optical response. Single-phase sphere-like CuInSe_2 nanocrystallite particles were prepared by a facile noninjection method with triethanolamine as the complexing agent and the solvent simultaneously. The period of the reaction was the key to form single-phase CuInSe_2 nanocrystals at 240 ^oC. TEM, XRD, XPS, EDX investigations were performed to characterize the morphology and the detailed structure of as-synthesized CuInSe_2 nanocrystals. All of the analysis results proved that the synthesized nanocrystals were pure phase and close to the stoichiometric ratio rather than a simple mixture. The band gap of the obtained CuInSe_2nanocrystals was 1.03 ± 0.03 eV.
Qiang Wang,Fengxia Xiao,Fei Qi,Xiaopeng Song,Yonghua Yu 대한암학회 2020 Cancer Research and Treatment Vol.52 No.2
Purpose Fractionated radiotherapy as well as concomitant and adjuvant chemotherapy such as temozolomide for postoperative high-grade glioma (HGG) patients improves progressionfree survival and overall survival. Multiple factors such as chemotherapy, radiotherapy, tumor grade, residual tumor volume, and genetic modifications might play a role in the formation of cognitive impairment. The risk factors of cognitive impairment in postoperative patients with HGG receiving radiotherapy and chemotherapy remains a concern in this population. The purpose of this study was to identify risk factors for cognitive impairment in patients of postoperative HGG. Materials and Methods A total of 229 patients with HGG who underwent surgery were analyzed. Cognitive impairment was defined as a decrease of Cognitive Assessment Montreal (MoCA)’s score in at least two cognitive domains or any MoCA’s score of less than 26 points at the time of study compared with baseline level. Multiple potential risk factors including methylated status of the O6-methylguanine-DNA methyltransferase (MGMT) promoter, glioma World Health Organization (WHO) grade, residual tumor volume, education, and sex were analyzed. Cox univariate and multivariate regression analysis was used to detect the significant risk factors for cognitive impairment. Results At the end of follow-up among the 229 patients, 147 patients (67%) developed cognitive impairment. 82 patients (36%) remained in normal cognitive condition. In multivariate analysis, unmethylated MGMT promoter (hazard ratio [HR], 1.679; 95% confidence interval [CI], 1.212 to 2.326; p=0.002), glioblastoma (HR, 1.550; 95% CI, 1.117 to 2.149; p=0.009), and residual tumor volume > 5.58 cm3 (HR, 1.454; 95% CI, 1.047 to 2.020; p=0.026) were independent risk factors for cognitive impairment. Conclusion Methylated status of the MGMT promoter, glioma WHO grade, and residual tumor volume might be risk factors for the cognitive impairment in postoperative patients with HGG.