On a Synchronous-Reluctance Motor Speed Drive with Intuitive Commutation Tuning

Kai-Wei Hu,Chang-Ming Liaw,Chiu-Fa Lee,Yu-Te Su 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper presents a synchronous reluctance motor (SynRM) drive with proper commutation instant tuning. Owing to the inaccurate and varied machine parameters, the optimal torque generating capability of a SynRM drive is difficult to achieve successfully. In the proposed intuitive commutation scheme, the commutation angle is first properly set by a minimum loss commutation (MLC) scheme and a field-weakening commutation (FWC) scheme. Then an intuitive commutation tuning (ICT) scheme is developed to adjust the commutation angle automatically for compensating the effects caused by the variations of system parameters and operating conditions. In addition, the current and speed controls are properly designed to yield good whole driving responses, including starting, acceleration/deceleration, reversible, dynamic and static running characteristics.

Joint Simulation of Trolley Vehicle-Frame Structure Coupled Vibration Using ADAMS and ANSYS for Container Crane Simulated Training System

Kai-liang Lu,You-fang Huang,Wei Yan,Jun Hu,Chao Chen,Dao-fang Chang 보안공학연구지원센터 2013 International Journal of Hybrid Information Techno Vol.6 No.5

Trichoderma biodiversity in major ecological systems of China

Kai Dou,Jinxin Gao,Chulong Zhang,Hetong Yang,Xiliang Jiang,Jishun Li,Yaqian Li,Wei Wang,Hongquan Xian,Shigui Li,Yan Liu,Jindong Hu,Jie Chen 한국미생물학회 2019 The journal of microbiology Vol.57 No.8

An investigation of Trichoderma biodiversity involving a large-scale environmental gradient was conducted to understand the Trichoderma distribution in China. A total of 3,999 isolates were isolated from forestry, grassland, wetland and agriculture ecosystems, and 50 species were identified based on morphological characteristics and sequence analysis of genetic markers. Trichoderma harzianum showed the largest proportion of isolates and the most extensive distribution. Hypocrea semiorbis, T. epimyces, T. konilangbra, T. piluliferum, T. pleurotum, T. pubescens, T. strictipilis, T. hunua, T. oblongisporum and an unidentified species, Trichoderma sp. MA 3642, were first reported in China. Most Trichoderma species were distributed in Jilin and Heilongjiang Provinces in northeast China and the fewest were distributed in Qinghai Province. Based on the division of ecological and geographic factors, forestry ecosystems and low-altitude regions have the greatest species biodiversity of Trichoderma.

Ginkgolide B Modulates BDNF Expression in Acute Ischemic Stroke

Wei, Hu,Sun, Tao,Tian, Yanghua,Wang, Kai The Korean Neurosurgical Society 2017 Journal of Korean neurosurgical society Vol.60 No.4

Objective : To investigate the neuroprotective effects of Ginkgolide B (GB) against ischemic stroke-induced injury in vivo and in vitro, and further explore the possible mechanisms concerned. Methods : Transient middle cerebral artery occlusion (tMCAO) mice and oxygen-glucose deprivation/reoxygenation (OGD/R)-treated N2a cells were used to explore the neuroprotective effects of GB. The expression of brain-derived neurotrophic factor (BDNF) was detected via Western blot and qRT-PCR. Results : GB treatment (4 mg/kg, i. p., bid) significantly reduced neurological deficits, water content, and cerebral infarct volume in tMCAO mice. GB also significantly increased Bcl-2/Bax ratio, reduced the expression of caspase-3, and protected against OGD/R-induced neuronal apoptosis. Meanwhile, GB caused the up-regulation of BDNF protein in vivo and in vitro. Conclusion : Our data suggest that GB might protect the brain against ischemic insult partly via modulating BDNF expression.

Analysis of Influence Factors on AC Breakdown Characteristics of Rod-Barrier Gap and Electric Field Simulation

Hu Kai,Li Guochang,Gu Zhenlu,Zhang Fan,Wei Yanhui,Lei Qingquan 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

The insulation performance of air gap can be improved by inserting insulation barriers into the high voltage box with limited space. The influence of the barrier dimension, barrier thickness, barrier position and surface state of epoxy resin barrier on the AC breakdown characteristics of the “rod electrode-insulation barrier-ground electrode” system are discussed in the work. An equal-size model of the insulation system is established to analyze the influence of the insulation barrier on electric field and the discharge mechanism. The experimental results indicate that the breakdown voltage is improved significantly by enlarging the barrier dimension, up to twice as much. In contrast, the barrier thickness has little effect on the breakdown voltage because the discharge is mainly along the barrier surface. Besides, the breakdown voltage can be increased by reducing the distance between insulation barrier and rod electrode, this is because of the blocking effect of insulation barrier on the corona layer around the electrode, which can hinder the development of charges to the ground electrode, thus delaying the discharge process. The breakdown voltage increases with the barrier surface roughness because of the prolongation of discharge path and the distortion of local electric field. The breakdown voltage decreases with the rise of temperature, it decreases to 37.5 kV when temperature rose to 60 °C. Due to the increase of free charges mobility, the corresponding surface resistivity decreases from 16.2 × 1014 Ω at 20 °C to 3.14 × 1014 Ω at 60 °C. This work can provide support for the reasonable design of insulation barriers in engineering application.

Effect of Ni2Si Precipitates on Microstructure and Mechanical Properties of Cu–Zn Brasses

Wei Chen,Kai You,Jufang Yin,Ming Chen,Xiaolan Tao,Jiarui Hu,Xiaorong Chen,Qian Lei 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10

Novel ultrahigh strength Ni2Sistrengthened brasses were fabricated, and microstructure and properties were investigatedusing scanning electron microscopy, optical microscopy, transmission electron microscopy, X-ray diffraction analysis, hardnessmeasurement, and electrical conductivity test. After optimal treatments (solid solution treated at 900 ℃ for 2 h, hotrolledby 80%, cold-rolled by 80%, and ageing treated at 300 ℃ for 8 h), the Cu-20Zn-3Ni-0.68Si alloy’s hardness, tensilestrength, yield strength, and electrical conductivity is 270.6 HV, 964 MPa, 933 MPa, 21.6%IACS, and 3.4%, respectively. δ-Ni2Si precipitates formed during the annealing process, which had a crystal orientation relationship with the matrix: (001)m// (001) δ, and [110]m// [100]δ. Quasi-cleavage fracture surfaces with shallow dimples were presented in both the Cu-20Zn-1.5Ni-0.34Si and the Cu-20Zn-3Ni-0.68Si alloy. These findings give a new method to develop new high strength low-costbrass copper materials.

Prognosis and Management for Gallbladder Cancer with Hepatic Invasion: Long-term Results of 139 Patients from a Single Center in China

Qu, Kai,Chang, Hu-Lin,Liu, Si-Nan,Liu, Chang,Xu, Xin-Sen,Wang, Rui-Tao,Zhou, Lei,Tian, Feng,Wei, Ji-Chao,Tai, Ming-Hui,Meng, Fan-Di Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.3

Objective: To improve the diagnosis of primary gallbladder carcinoma (GBC) with/without hepatic metastases by analyzing our experience of different GBC treatment in our patients. Methods: A retrospective study was carried out to analyze the clinical data of the 139 patients with GBC who underwent hepatic resection in our unit from January 2003 to December 2007. Patients were divided into two groups according to whether they demonstrated hepatic invasion. Tumor presentation, surgical modes, and prognosis of each patient were retrospectively reviewed. Kaplan-Meier curves and log-rank tests were employed to compare the survival rates of those patients undergoing different surgical procedures. Results: Of the 139 patients, 46 were men and 93 were women with the male to female ratio of 1:2.0. Their ages were ranged from 35 to 86 years with a mean age of $62.8{\pm}10.4$ years. There were 73 patients complicated with hepatic invasion (group A), and no hepatic invasion occurred in the other 66 patients (group B). Compared with the group B, the patients with hepatic invasion suffered lower differentiation of tumor (p=0.000), more advanced Nevin staging (p=0.008) and poorer prognosis (p=0.013). Radical resection were more frequently performed in group B (75.76%) than in group A (45.20%) with better outcomes (p=0.000). Conclusion: GBC patients complicated with hepatic invasion had poorer prognosis than those without invasion in long-term follow-ups. Radical resection might result in a satisfied prognosis in patients without hepatic invasion, but appears less favorable than palliative resection in those who were complicated with hepatic invasion.

<i>In Situ</i> Observation and Electrochemical Study of Encapsulated Sulfur Nanoparticles by MoS₂ Flakes

Tang, Wei,Chen, Zhongxin,Tian, Bingbing,Lee, Hyun-Wook,Zhao, Xiaoxu,Fan, Xiaofeng,Fan, Yanchen,Leng, Kai,Peng, Chengxin,Kim, Min-Ho,Li, Meng,Lin, Ming,Su, Jie,Chen, Jianyi,Jeong, Hu Young,Yin, Xuesong American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.29

<P>Sulfur is an attractive cathode material for next-generation lithium batteries due to its high theoretical capacity and low cost. However, dissolution of its lithiated product (lithium polysulfides) into the electrolyte limits the practical application of lithium sulfur batteries. Here we demonstrate that sulfur particles can be hermetically encapsulated by leveraging on the unique properties of two-dimensional materials such as molybdenum disulfide (MoS<SUB>2</SUB>). The high flexibility and strong van der Waals force in MoS<SUB>2</SUB> nanoflakes allows effective encapsulation of the sulfur particles and prevent its sublimation during <I>in situ</I> TEM studies. We observe that the lithium diffusivities in the encapsulated sulfur particles are in the order of 10<SUP>–17</SUP> m<SUP>2</SUP> s<SUP>–1</SUP>. Composite electrodes made from the MoS<SUB>2</SUB>-encapsulated sulfur spheres show outstanding electrochemical performance, with an initial capacity of 1660 mAh g<SUP>–1</SUP> and long cycle life of more than 1000 cycles.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2017/jacsat.2017.139.issue-29/jacs.7b05371/production/images/medium/ja-2017-05371c_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja7b05371'>ACS Electronic Supporting Info</A></P>

Gallbladder Cancer: a Subtype of Biliary Tract Cancer Which is a Current Challenge in China

Qu, Kai,Liu, Si-Nan,Chang, Hu-Lin,Liu, Chang,Xu, Xin-Sen,Wang, Rui-Tao,Zhou, Lei,Tian, Feng,Wei, Ji-Chao,Tai, Ming-Hui,Meng, Fan-Di Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Biliary tract cancers, broadly described as malignancies that arise from the biliary tract epithelia, are usually divided into two major clinical phenotypes: cholangiocarcinoma and gallbladder cancer, differing in etiopathogenesis, risk factors, and perhaps molecular and genetic signatures. Atypical symptoms and lack of tumor biomarkers make it difficult to diagnose in early stages. At the time of presentation, few patients are candidates for potentially curative surgical resection. We here assessed and compared features of a total of 150 cases divided into extra- and intrahepatic cholangiocarcinomas and gallbladder cancers (GBC). Althought there were no significant differences in serum tumour marker levels, GBC patients had the poorest prognosis. Furthermore, gallbladder cancer respond poorly to chemotherapy or radiation therapy and approximately half of untreated patients died within 10 months. Therefore, treatment for patients with gallbladder cancer is still in challenge. Outcomes and survival of these patients had improved little over the past three decades - a period in which new successful treatments have greatly contributed to the prolonged patient survival for many other cancers.

Enhanced photocatalytic activity of TiO2/graphene by tailoring oxidation degrees of graphene oxide for gaseous mercury removal

Yu Guan,Tao Hu,Jiang Wu,Lili Zhao,Fengguo Tian,Wei-Guo Pan,Ping He,Xuemei Qi,Fangqin Li,Kai Xu 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.1

We used a simple method of graphene oxide (GO) preparation with different oxidation levels, and control the properties of the TiO2 nanocrystals by tuning the content and oxidation degree of GO to enhance the photocatalytic performance. During the hydrothermal reaction, reduction of GO, formation of TiO2 and chemical bonds between TiO2 and reduced graphene oxide (RGO) was achieved simultaneously. Characterization results showed that TiO2 properties such as crystalline grain and particle size could be tailored by the amount of functional groups, and that crystallinity was also controlled by GO degrees of oxidation. TiO2/RGO photocatalysts showed great efficiency of mercury oxidation, which reached 83.7% and 43.6% under UV and LED light irradiation, respectively. The effects of crystalline grain size and surface chemical properties on Hg0 removal under LED and UV light irradiation were analyzed. In addition, the properties of the photocatalysts before and after UV illumination were investigated, finding that part of Ti-OH on TiO2 surface transformed to Ti-O-Ti. In a nutshell, this work could provide a new insight into enhancing activity of photocatalysts and understanding the photocatalytic mechanism.