A New Technology of Comprehensive Islanding Detection

Linlin Gao,Zhiyou Ren,Zhongqiang Ge,Aijun Zhang 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.6

With the widely application of the distributed generation technology, micro grid islanding detection technology has been greatly developed. A new type of islanding detection technique is proposed in this paper. The new detection technology has realized the rapid, efficient, stable and reliable islanding detection, and achieved the zero non detection zone. At the same time, which put money into limit in minimum range. This paper presents the principle of islanding comprehensive detection technology. This paper designs and describes the method to realize the new islanding detection technology. The new technology makes up for a series of shortcomings,such as the non-detection zone (NDZ) is larger of the local testing technology. And it also overcomes a great many shortcomings of the remote detection technology, such as a big investment and too single.

A Review of Islanding Detection Methods for Photovoltaic Generation System

Linlin Gao,Jinsong Liu 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.6

Ion Exchange Synthesis of Bi2MoO6/BiOI Heterojunctions for Photocatalytic Degradation and Photoelectrochemical Water Splitting

Linlin Fan,Bo Wei,Lingling Xu,Yang Liu,Wanlu Cao,Ning Ma,Hong Gao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.8

In this study, flower-like Bi2MoO6/BiOI heterostructure photocatalysts were synthesized via an anion exchange method using BiOI as precursor. The composition of Bi2MoO6/BiOI can be easily controlled by adjusting the MoO2- 4 /I- molar ratio. Photocatalytic activity studies based on the degradation of Rhodamine B (RhB) show that Bi2MoO6/BiOI = 50% photocatalyst exhibited the best performance under visible light excitation. The radical scavengers test demonstrated that holes was the main reactive species for the degradation of RhB, and O2- also took part in the photodecomposition process. Photoelectrochemical measurement reveals that the Bi2MoO6/ BiOI = 50% exhibit enhanced carrier densities, charge separation and photocurrent compared with the original Bi2MoO6 and BiOI. Our results show that bismuth-based heterojunctions fabricated through the anion exchange method could be a cost-effective approach to improve the photocatalytic activity and photoelectrochemical performance of BiOI.

Epidemiological investigation and phylogenetic analysis of Classical Swine Fever virus in Yunnan province from 2015 to 2021

Jun Yao,Linlin Su,Qiaoping Wang,Lin Gao,Jiarui Xie,Yuwen He,Xianghua Shu,Chunlian Song,Jun Chai,Yifang Zhang,Shibiao Yang 대한수의학회 2022 Journal of Veterinary Science Vol.23 No.4

Background: Classical swine fever virus (CSFV), the causative agent of classical swine fever (CFS), is a highly contagious disease that poses a serious threat to Chinese pig populations. Objectives: Many provinces of China, such as Shandong, Henan, Hebei, Heilongjiang, and Liaoning provinces, have reported epidemics of CSFV, while the references to the epidemic of CSFV in Yunnan province are rare. This study examined the epidemic characteristics of the CSFV in Yunnan province. Methods: In this study, 326 tissue samples were collected from different regions in Yunnan province from 2015 to 2021. A reverse transcription-polymerase chain reaction (RT-PCR), sequences analysis, and phylogenetic analysis were performed for the pathogenic detection and analysis of these 326 clinical specimens. Results: Approximately 3.37% (11/326) of specimens tested positive for the CSFV by RT-PCR, which is lower than that of other regions of China. Sequence analysis of the partial E2 sequences of eleven CSFV strains showed that they shared 89.0–100.0% nucleotide (nt) and 95.0–100.0% amino acid (aa) homology, respectively. Phylogenetic analysis showed that these novel isolates belonged to the subgenotypes 2.1c and 2.1d, with subgenotype 2.1c being predominant. Conclusions: The CSFV was sporadic in China’s Yunnan province from 2015 to 2021. Both 2.1c and 2.1d subgenotypes were found in this region, but 2.1c was dominant.

Error modeling and accuracy optimization of rotating ultrasonic vibration assisted EDM machine tool

Minggang Xu,Zhiwei Wu,Feng Gao,Linlin Liu,Enyu Song 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.7

Rotating ultrasonic vibration assisted EDM is a composite machining method that uses EDM to etch a metal surface and adds rotating and ultrasonic vibration. It has high efficiency and a wide range of workpiece materials. Aiming at the structural characteristics of rotary ultrasonic vibration assisted EDM machine tool, the errors caused by the main moving parts of the machine tool were analyzed. The structure relationship is described by multi-body system theory, and the geometric error model is deduced by homogeneous coordinate transformation method. The aim was to improve the overall accuracy, reduce the cost, trace the error source, and get the corresponding relationship between the basic geometric errors and the precision parameters of the related parts. Under the requirement of ensuring the overall accuracy, an optimization function was established that minimizes the cost and relaxes all accuracy parameters to the greatest extent. Finally, MATLAB and its genetic algorithm toolbox was used for analysis. Verification shows that this model can properly reduce the cost on the premise of ensuring the accuracy.

Forest Fire Smoke Recognition Based on Gray Bit Plane Technology

Yinglai Huang,Shaoqing Tian,Xiaofang Sun,Meng Gao,Linlin Dai 보안공학연구지원센터(IJSIP) 2013 International Journal of Signal Processing, Image Vol.6 No.6

Hydraulic components’ matching optimization design and entropy production analysis in a large vertical centrifugal pump

Gang Yang,Xutao Zhao,Desheng Zhang,Linlin Geng,Xueqi Yang,Xiongfa Gao 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.11

The large vertical centrifugal pump is the core power equipment for longdistance water division and large-scale irrigation projects. The power of the matching motor can reach 40 MW. In view of reducing the operating energy consumption of this kind of pump, the efficiency under the design condition was taken as the optimization objective, and a matching optimization on hydraulic components was proposed in this research. The optimization process was divided into two stages. The first stage focused on improving the configuration of the vane diffuser. In the second stage, the Plackett-Burman test design was used to screen out the optimization design variables of the vane diffuser and the volute, the optimal Latin hypercube sampling method was adopted to generate 106 sample cases, and an automatic numerical simulation optimization platform was built. Then, different approximate models were employed to construct the relationship between the optimization design variables and the objective function, and their fitting accuracy and robustness were compared. Finally, the optimal design parameters were determined by particle swarm optimization, and entropy production theory was used to analyze the internal flow pattern of the model before and after optimization. Results showed that D 3 , b 4 , β 3 , and S 8 have the greatest impact on the hydraulic efficiency of the pump. The multilayer backpropagation neural network has a higher fitting accuracy and better robustness compared with the other three approximate models. The efficiency of the optimized model under the design condition is increased by 4.22 %, reaching 90.82 %. Reducing the number of layers and vanes of the diffuser and improving the matching of hydraulic components can dramatically improve the hydraulic performance and hump characteristics of large vertical centrifugal pumps. Entropy production theory is a reliable approach to visualizing flow loss. The turbulent flow dissipation in the vane diffuser can be reduced the most after optimization.

Granulation of Activated Sludge in a Continuous Flow Airlift Reactor by Strong Drag Force

Dandan Zhou,Mengyuan Liu,Jun Wang,Shuangshi Dong,Ning Cui,Linlin Gao 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2

Most aerobic granule cultivation has been based on the sequencing batch reactor (SBR) and then the factors that affect aerobic granulations were developed in the SBR. However, little work has been done to cultivate aerobic granules in a continuous-flow bioreactor with simple structure that is realistic for engineering. This work is the first to cultivate aerobic granules in a continuous flow airlift fluidized bed reactor (CAFB) possesses a very simple structure and without settling time and starvation time controlling. The configuration of CAFB was the simplest continuous-flow aerobic granular bioreactor reported by now. The majority of granules could be formatted in the CAFB after 12 days cultivation. The effluent COD concentration maintained at 50 ± 10 mg/L for the variable COD loading rate of 3.5 g COD/L/d and 4.8 g COD/L/d, which confirmed that the CAFB performed good anti-shock abilities. CAFB performed good nitrification ability, however, little denitrification was found under the operating conditions of this study. The shear stress acting on the solid phase were hundreds of times stronger in the CAFB than in the SBR at the same aeration strength. It seems CAFB is very efficient for granulation due to the strong shear-force exertion,which is promising for continuous-flow aerobic granular bioreactor. Protein, positive to the hydrophobicity, was predominant in extracellular polymeric substances in the granules, and favored the granules formation in the CAFB combined with the polysaccharides. However, filamentous bulking always happened in 35 days operation of the CAFB, thus further study on the stability of this bioreactor is urgently necessary.

Metabolomes and transcriptomes revealed the saponin distribution in root tissues of Panax quinquefolius and Panax notoginseng

Wei, Guangfei,Yang, Feng,Wei, Fugang,Zhang, Lianjuan,Gao, Ying,Qian, Jun,Chen, Zhongjian,Jia, Zhengwei,Wang, Yong,Su, He,Dong, Linlin,Xu, Jiang,Chen, Shilin The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.6

Background: Panax quinquefolius and Panax notoginseng are widely used and well known for their pharmacological effects. As main pharmacological components, saponins have different distribution patterns in the root tissues of Panax plants. Methods: In this study, the representative ginsenosides were detected and quantified by desorption electrospray ionization mass spectrometry and high-performance liquid chromatography analysis to demonstrate saponin distribution in the root tissues of P. quinquefolius and P. notoginseng, and saponin metabolite profiles were analyzed by metabolomes to obtain the biomarkers of different root tissues. Finally, the transcriptome analysis was performed to demonstrate the molecular mechanisms of saponin distribution by gene profiles. Results: There was saponin distribution in the root tissues differed between P. quinquefolius and P. notoginseng. Eight-eight and 24 potential biomarkers were detected by metabolome analysis, and a total of 340 and 122 transcripts involved in saponin synthesis that were positively correlated with the saponin contents (R > 0.6, P < 0.05) in the root tissues of P. quinquefolius and P. notoginseng, respectively. Among them, GDPS1, CYP51, CYP64, and UGT11 were significantly correlated with the contents of Rg1, Re, Rc, Rb2, and Rd in P. quinquefolius. UGT255 was markedly related to the content of R1; CYP74, CYP89, CYP100, CYP103, CYP109, and UGT190 were markedly correlated with the Rd content in P. notoginseng.

Predictions of Bending Modal Properties of the 3D Braided Composites with the Homogeneous Theoretical Model

Tao Liu,Jingjing Dong,Chaonan Ye,Xianyan Wu,Wei Fan,Linlin Lu,Jingyu Kang,Xingzhong Gao,Baozhong Sun,Honglei Yi 한국섬유공학회 2022 Fibers and polymers Vol.23 No.12

In this work, the bending modal properties of three-dimensional (3D) braided composites were investigated withthe experimental and numerical methods. Three braided angles were selected to study the braided angle effect on the modalbehavior of 3D braided composites. According to the experimental parameters, a homogeneous model containing the interior,surface and corner representative unit cells of the braided composites were proposed to compute the elastic constants of eachcomposite. Besides, the fiber breakage defects were introduced to the homogeneous model to improve the accuracy ofpredicting the modal behavior of the braided composite. The results indicate that the increase of the braided angle and thefiber breakage defects could apparently reduce the natural frequency of the braided composite. The modal propertiessimulated by the homogeneous models containing some fiber breakage defects could fit well with the correspondingexperimental results. The proposed method to create the homogenous model can be used to predict the modal behavior of the3D braided composites.