http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
과거 30년간 기온상승으로 인한 한반도 생물계절성 변화 연구
Xu, JinFeng,ZHUYONGYAN,Meng, Su Xin,Huang, Xiao,PIAODONGFAN,Cui, Gui Shan 한국기후변화학회 2019 한국기후변화학회지 Vol.10 No.4
Vegetation phenology changes play a key role in the carbon and nutrient cycle of terrestrial ecosystems. Phenology findings based on satellite observations have mainly concentrated on the northern hemisphere or Eurasia and the American continent, with few small‐scale studies on special climate environments. In this study, we used five methods to extract the Start of Growing Season (SOS), End of Growing Season (EOS) and Length of Growing Season (GSL) dates from NDVI records for the Korean Peninsula from 1982 to 2015, and determined the time correlation between SOS, EOS and maximum temperature (Tmax) and minimum temperature (Tmin). In general, phenological changes in the Korean peninsula vary from the findings drawn from the northern hemisphere scale. The SOS advance rate on the Korean peninsula is about 0.01 days / year, the fall phenology delay rate is about 0.24 days per year (p <0.05), and the growing season extension rate is about 0.23 days/year. By investigating the phenology of North Korea and South Korea separately using the 38‐line boundary, we found no statistically significant changes in SOS and GSL in North Korea. At the same time, SOS, EOS, and GSL in South Korea have changed significantly over this period. The prolongation of the growing season on the Korean Peninsula is mainly due to the delayed phenology of autumn. Vegetation phenology in South Korea’s marine climate is more strongly influenced by Tmin.
Jinfeng Zhang,Guanyi Chen,Yanning Ma,Miao Xu,Songyan Qin,Xiaoliang Liu,Haijun Feng,Lian Hou 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.1
A new technique for treating pickling wastewater discharged from the steel industry using membrane filters was developed and membrane fouling was characterized in a full scale membrane filter. The morphological and chemical properties were examined through scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) etc. The results showed that inorganic elements such as phosphates, chlorides, and sulfates were severely blocked in membrane surfaces and pores. The porosity, permeability, hydrophilic contact angle, and surface charge capacity of fouled membranes were all lower than those of new membranes, while the optimal neutralization reaction pH region for fouled membranes shifted and narrowed. Charge neutralization is a critical reason to membrane fouling. By increasing the Zeta potential of the pickling wastewater, the membrane fouling could be controlled. This method is proven to effectively improve the separation property of precipitates after pickling wastewater was neutralized. Moreover, Neutralization helped to reduce the unit number of treatment processes. This investigation could assist in obtaining a better understanding of the fouling properties and behavior in the full-scale membrane filters in the pickling wastewater treatment.
Ship Number Recognition Method Based on An improved CRNN Model
Wenqi Xu,Yuesheng Liu,Ziyang Zhong,Yang Chen,Jinfeng Xia,Yunjie Chen 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.3
Text recognition in natural scene images is a challenging problem in computer vision. The accurate identification of ship number characters can effectively improve the level of ship traffic management. However, due to the blurring caused by motion and text occlusion, the accuracy of ship number recognition is difficult to meet the actual requirements. To solve these problems, this paper proposes a dual-branch network based on the CRNN identification network. The network couples image restoration and character recognition. The CycleGAN module is used for blur restoration branch, and the Pix2pix module is used for character occlusion branch. The two are coupled to reduce the impact of image blur and occlusion. Input the recovered image into the text recognition branch to improve the recognition accuracy. After a lot of experiments, the model is robust and easy to train. Experiments on CTW datasets and real ship maps illustrate that our method can get more accurate results.
Liu Jinfeng,Xu Zhaoyun,Zhang Zhenglei,Iu Herbert Ho-Ching 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1
The low voltage, high current rectifer module is the core of the integrated DC output system based on synchronous generators. In addition, modular control improves the fexibility of the system control and fault-tolerant operation ability. Due to the dispersion of the on-state voltage drop of switching devices, it is possible to cause a circulating current fault between the parallel modules, which leads to the reduction of the current sharing characteristics and stability of the system. Therefore, it is signifcant to address the shortcomings of traditional current sharing methods such as poor anti-disturbance performance. This paper proposes a current sharing scheme that improves the control accuracy by fltering the sampled current on the basis of autonomous sharing of maximum current. Furthermore, a model of the integrated generator rectifer system was established by Simulink to realize the simulation of the modular SVPWM (Space-Vector Pulse-Width Modulation) rectifer control based on MA (Moving Average) fltering algorithm. At last, an experimental platform was built in this paper in order to verify the feasibility of the theory. In this experimental platform, the controller completes digital current sharing control and fnally realizes the synchronous generator module paralleling system 5 V/1000A DC output. The simulation and experiment demonstrate that the integrated output current sharing control method in this paper has higher control precision and better anti-interference performance.
Temperature Effect Analysis of Large Segment Factory Manufacturing Alignment of Steel Box Girder
Deng Fuqiang,Wang Jinfeng,Yang Songwei,Xu Linghua,Xu Rongqiao 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.1
The construction of the cross-sea steel box girder bridge is gradually advancing and integrating, which particularly refl ects in the size of the bridge. The length of a single installation segment often exceeds 100 m. The alignment of the steel box girder is signifi cantly aff ected by the temperature eff ect during manufacturing. This paper investigates the impact of temperature gradient on corresponding alignment at the manufacturing stage for the large-segment steel box girder taking a large-span continuous steel box girder bridge as a case study. The inspection of temperature during the assembly procedure was carried out. After obtaining the data during welding, the infl uence of the temperature was evaluated using a fi nite element model. The results show that with the temperature gradient measured, the defl ection of the second suspension of the mid-span reaches 10.9 mm and the defl ection of the cantilever end reaches 17.1 mm, respectively. The deformation conforms to the code specifi cations when considering the infl uence of the temperature gradient eff ect. The corresponding pre-camber value should be set for the large segments assembled outdoor. At the same time, welding operation should be carried out under the preset temperature diff erence to partially eliminate the impact of temperature gradient.