호이스트용 SRM의 구동시스템의 특성해석

이진국,이동희,안진우 경성대학교 공학기술연구소 2005 공학기술연구지 Vol.12 No.-

This paper presents a development of Switched Reluctance Motor (SRM) drive system for a hoist application. In the hoist system, smoothing start-up and braking are very important for a protection of goods. In order to improved a start-up and a stop performance of hoist system, the smoothing operation sequence of SRM using direct instantaneous torque control is proposed. The proposed Direct Instantaneous Torque Control (DITC) the instantaneous torque of SRM according to the switching sequence and hysteric band. In order to compare the reference and actual torque of SRM, pre-measured flux and torque look-up table are regulate used. The proposed SRM Drive system is verified by the simulation result.

4-레벨 인버터를 이용한 고속 SRM 구동시스템

이동희,이진국,안진우 경성대학교 공학기술연구소 2005 공학기술연구지 Vol.12 No.-

This paper proposes high speed SRM drive system for blower with a novel 4-level inverter and precise excitation position generator. In order to get a fast build-up and a demagnetization of excitation current, 4-level inverter system is proposed. The proposed 4-level inverter has additional charge capacitor, power switch and diode in the conventional asymmetric converter. The charged high voltage is supplied to the phase winding for fast current build- up, and demagnetization current is charged to additional capacitor of 4-level inverter. In addition, a precise excitation position generator can reduce turn-on and turn-off angle error according to sampling period of digital control system. The proposed high speed SRM drive system is verified by computer simulations and experimental results.

The relationship between bacterial diversity and organic carbon mineralization in soft rock and sand compound soil

Guo Zhen,Li Juan,Ge Lei,Yang Chenxi,Han Jichang 한국미생물학회 2020 The journal of microbiology Vol.58 No.9

The soil organic carbon (SOC) mineralization rate in sandy soil plays an important role in improving soil quality, and a research is needed to determine management practices that optimize the mineralization rate. When sandy soil is improved by adding soft rock, the specific promotion process of bacterium to SOC mineralization remain unclear. To investigate these mechanisms, we selected four treatments with soft rock to sand volume ratios of 0:1 (CK), 1:5 (C1), 1:2 (C2) and 1:1 (C3) to study. The mineralization rate of organic carbon was measured using the lye absorption method. Highthroughput sequencing and scanning electron microscopy were used to determine the bacterial community structure and soil microstructure, respectively. The results showed that the organic carbon content of the sandy soil increased significantly (182.22–276.43%) after using the soft rock treatments. The SOC mineralization rate could be divided into two stages: a rapid decline during days 1–8 and a slow decline during days 8–60. With increased incubation time, the intensity of the cumulative release of organic carbon gradually weakened. Compared with the CK treatment, the SOC mineralization accumulation (Ct) and the potential mineralizable organic carbon content (C0) in the C1, C2, and C3 treatments increased significantly, by 106.98–225.94% and 112.22– 254.08%, respectively. The cumulative mineralization rate (Cr) was 18.11% and 21.38% smaller with treatments C2 and C3, respectively. The SOC mineralization rate constant (k) decreased significantly after the addition of soft rock, while the half-turnover period (Th) changed inversely with k. Compared with the CK treatment, the number of gene copies of the soil bacteria increased by 15.38–272.53% after adding soft rock, with the most significant increase in treatment C3. The bacterial diversity index also increased significantly under treatment C3. The three dominant bacteria were Proteobacteria, Actinobacteria, and Chloroflexi. The correlation between Cr and one of the non-dominant bacteria, Firmicutes, was large, and the bacteria had a significant positive correlation with k. At the same time, the abundance of Firmicutes under treatments C2 and C3 was small. As the proportion of soft rock increased, the soil particles changed from point contact to surface contact, and the adhesion on the surface of the particles gradually increased. Results from this study show that the retention time of SOC can be increased and the carbon sequestration effect is better when the ratio of soft rock to sand is set to 1:2.

PLCE1 Gene in Esophageal Cancer and Interaction with Environmental Factors

Guo, Li-Yan,Zhang, Shen,Suo, Zhen,Yang, Chang-Shuang,Zhao, Xia,Zhang, Guo-An,Hu, Die,Ji, Xing-Zhao,Zhai, Min Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.7

Objective: To study the PLCE1 gene rs2274223 polymorphism with regard to esophageal cancer and its interaction with diet, lifestyle, psychological and environmental factors in Southwest Shandong province. Materials and Methods: A case series study (case-case) was conducted. Questionnaire data were collected and 3 ml-5ml venous blood was drawn for DNA extraction among the qualified research subjects. PLCE1 gene polymorphism was detected after PCR amplification of DNA. SPSS 13.0 software was used for statistical analysis of the data. Results: The three genotypes A/A, A/G and G/G PLCE1 gene rs2274223 was 31, 16 and 4 cases, accounting for 60.8%, 31.4%, 0.08% respectively. The difference of three genotypes (AA/GA/GG) proportion between negative and positive family history of patients was statistically significant, ${\chi}^2=6.213$, p=0.045. There was no statistically significant relationship between PLCE1 gene rs2274223 polymorphism and smoking, drinking, ${\chi}^2=0.119$, p=0.998, and ${\chi}^2=1.727$, p=0.786. There was no linkage of the three rs2274223 PLCE1 gene genotypes (AA/GA/GG) proportion with eating fried, pickled, hot, mildew, overnight, smoked, excitant food, eat speed, salt taste or not (p>0.05). or with living environment pollution and nine risk factors of occupational exposure (p>0.05). There was no statistically significant difference in TS scores between different genotype of rs2274223 PLCE1 gene. Conclusions: The PLCE1 rs2274223 polymorphism has a relationship with family history of esophageal cancer, but does not have any significant association with age, gender, smoking, alcohol drinking, food hygiene, eating habits, living around the environment and occupation in cases.

Behaviour of Endplate Joints Subjected to Elevated Temperature after Cyclic Loads

Zhen Guo,Xuecheng Zhang,Xingzhi Jia 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.11

This paper presents the performance of an end-plate joint at elevated temperature after cyclic loads. Prime interest of the end-plate joints, subjected to elevated temperature, lies on the effect of three kinds of external conditions: monotonic loads, cyclic loads and local damages. Parametric studies have been systematically conducted using simplified models. The Behaviour of endplate joints subjected to high temperature is examined under two levels of damage caused to the structure, i.e., deformation damage and fracture damage under earthquake. Numerical results indicate that dead loads on beam and material properties of endplate joints are still playing a significant role in fire resistance. Under only deformation damage, the dominance of joints’ resistance to fire is still primarily the property of the material itself. Once experiencing fracture damage, for instance endplates fracture and bolts breakage, the behaviour of joints will degrade severely in post-earthquake fire. The results of this study demonstrate that the deformation damages has limited effect on the endplate joint at elevated temperature after an earthquake. The achieved results can be adopted during the design stage in order to minimize the probability of collapse in the fire.

Fatigue Life Estimation of Cold Drawn Contact Wire

Guo, Zhen,Kim, Yong-Seok,Hong, Suk-Woo,Li, Hao-Chuang,Koo, Jae-Mean,Seok, Chang-Sung,Lee, Ki-Won,Kwon, Sam-Young Korean Society for Precision Engineering 2014 International Journal of Precision Engineering and Vol.15 No.11

To evaluate the bending fatigue characteristics of contact wire, a stroke-based bending fatigue tester on contact wire has been developed by Kang et al. But this tester is too cumbersome and complicated. This paper is investigated with a new fatigue life estimation method based on Juvinall's method for estimation of S-N curve, which is widely used in steel structure, in order to estimate the bending S-N curve of cold drawn contact wire. First, the ultimate tensile strength and the axial tension fatigue test was performed with standard specimens, and the bending fatigue life for the cold drawn contact wire structure was predicted by using an improved S-N curve prediction method. Finally, the tested bending fatigue life of the structure was compared with the fatigue life estimated by the new method. As the result, the predicted bending S-N curve of the contact wire agreed fairly well with the experimental bending fatigue lives using the S-N curve and ultimate tensile strength of cold drawn material.

Bending Fatigue Life Evaluation of Cu-Mg Alloy Contact Wire

Guo Zhen,석창성,김용석,Li Haochuang,구재민,이기원,권삼영 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.7

Contact wire is one of the most important components used to supply electricity to railway vehicles which equipped with apantograph. When the speed of electric vehicle is not as high as now, the failure of contact wire caused by friction and wear behaviorsof carbon strip/contact wire were considered more important. But the fatigue fracture become more and more important for the failureof contact wires on account of several fatigue fractures happened while the speed of electric vehicle increase continuously. A bendingfatigue tester simulating the working conditions of contact wires developed by Kang and etc has been used to evaluate the fatiguecharacteristic of pure copper and Cu-Sn alloy contact wires. In this study, this bending fatigue tester also is used to evaluate thefatigue characteristics of Cu-Mg alloy contact wire which developed for 400km/h high speed rail in Korea. Test result is alsocompared with the result of Kang's research on pure copper contact wire. Finally, in order to evaluate the fatigue life of contact wiresfor any mean stress, the relationships between plastic strain and fatigue life were abstained for two kinds of contact wires combinedthe FE analysis.

Experimental Study of Steel Plate Composite Shear Wall Units under Cyclic Load

Zhen Guo,Yingshu Yuan 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.3

A novel type of steel plate composite shear wall that was assembled by using a steel plate and precast cement-based concrete plate is presented in this paper. The steel plate shear wall, which differs from normal steel plate shear walls, was trilaterally constrained with an elastic restraint side. The precast concrete slab was designed to prevent steel plate buckling. Six steel plate shear wall specimens were tested by using a hydraulic servo actuator. The failure mode, shear resistance, lateral stiffness, and buckling mode were investigated through an experimental study. The results indicate that the width-thickness ratio of the steel plate affected the shear-carrying capacity and failure mode. A low width-thickness ratio of steel plate required adequate bonding to prevent boundary failure. The precast concrete slabs enhanced the lateral stiffness and improved the buckling strength or shear resistance of the steel plate. The material workable capability of steel plate was fully developed with a composite buckling-restraint by using the composite shear wall; similarly, the earthquake-resistant behavior of the structural system would likewise be enhanced further.

Internet Gateway Technology for Intranet Use

Guo Zhen Sheng,Wong Chan Tang 대한전자공학회 1997 ITC-CSCC :International Technical Conference on Ci Vol.- No.-

An Integrated Multi-Form Mail System

Guo Zhen Sheng,Gregory Sun Kuan Jeong,Joao Baptista Siu,Kenneth Ho Leong Hou 대한전자공학회 1996 ITC-CSCC :International Technical Conference on Ci Vol.- No.-