55 results on '"Z J, Shen"'
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2. Modeling and simulation of bulk gallium nitride power semiconductor devices
- Author
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G. Sabui, P. J. Parbrook, M. Arredondo-Arechavala, and Z. J. Shen
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Physics ,QC1-999 - Abstract
Bulk gallium nitride (GaN) power semiconductor devices are gaining significant interest in recent years, creating the need for technology computer aided design (TCAD) simulation to accurately model and optimize these devices. This paper comprehensively reviews and compares different GaN physical models and model parameters in the literature, and discusses the appropriate selection of these models and parameters for TCAD simulation. 2-D drift-diffusion semi-classical simulation is carried out for 2.6 kV and 3.7 kV bulk GaN vertical PN diodes. The simulated forward current-voltage and reverse breakdown characteristics are in good agreement with the measurement data even over a wide temperature range.
- Published
- 2016
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3. Effects of ambient temperature on growth performance and carcass traits of male growing White Pekin ducks
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Z J Shen, Ming Xie, P X Sun, Wei Huang, J. Tang, and Shuisheng Hou
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Male ,Hot Temperature ,Meat ,040301 veterinary sciences ,Biology ,Weight Gain ,Body weight ,Feed conversion ratio ,0403 veterinary science ,Random Allocation ,Animal science ,medicine ,Abdominal fat ,Animals ,Body Weight ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,General Medicine ,040201 dairy & animal science ,Heat stress ,Cold Temperature ,Ducks ,Critical level ,Animal Science and Zoology ,medicine.symptom ,Weight gain ,Food Science - Abstract
1. An experiment was conducted to investigate the effects of ambient temperature on growth performance and carcass traits in male growing Pekin ducks from 14 to 42 d of age in order to establish their optimal temperature requirements. 2. A total of 216 14 d old male White Pekin ducks were allocated randomly to six environmentally controlled chambers with ambient temperature set at 20°C, 22°C, 24°C, 26°C, 28°C, and 30°C from 14 to 42 d of age, respectively. 3. As ambient temperature increased from 20°C to 30°C, the body weight and weight gain decreased linearly or quadratically (P < 0.05) and was accompanied by linearly decreasing feed intake (P < 0.05). According to broken-line regression, the upper critical level of ambient temperature during the growing period for body weight, weight gain, and feed conversion ratio were 27.4°C, 27.4°C, and 26.0°C, respectively. 4. The weight of breast meat, leg meat, and abdominal fat decreased linearly or quadratically as ambient temperature increased and declined to a minimum when the temperature increased to 30°C (P < 0.05). The percentage of breast meat and abdominal fat showed a linear or quadratic decreasing response to increasing temperature, but leg meat percentage increased as temperature increased and reached maximum at 30°C (P < 0.05). According to broken-line regression, the upper critical ambient temperatures during the growing period for breast meat weight and percentage were 25.5°C and 25.6°C, respectively. 5. It was concluded that both growth performance and breast meat of growing ducks were sensitive to increasing ambient temperature and this should be kept below the upper critical temperature during the growing period in order to optimise growth performance and carcass traits at market age.
- Published
- 2019
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4. [Trend of collaboration and sharing in digitalized restorative dentistry]
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Z J, Shen and L, Song
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Dental Prosthesis Design ,Artificial Intelligence ,Dentistry ,Computer-Aided Design ,Humans ,Esthetics, Dental ,Prosthodontics ,Ecosystem - Abstract
To digitalize restorative dentistry means to digitalize all the approaches involved in the clinical diagnosis and treatment process, in the production of individualized restorations, in the information transmission and communication between dentists and patients respectively between dentists and technicians, and even in the personalized understanding of esthetics. This is a cross-disciplinary issue that interconnects a wide range of topics. The way of understanding the digital tendency and of integrating the-already-digitalized steps into a system have a strategic impact on the development of the dental industry. By following the trace of the development of digital procedures in restorative dentistry, in this paper, we intend to classify the digitalization into two categories as the special and general ones, and will point out the limitations in understanding the digitalization in prosthodontics merely from the perspective of diagnosis or the production of individualized restorations. The role of digitalization in leading the conceptual development and the new possibilities opened up by the integrated digital technologies will be emphasized. Digitalization has changed the way of interaction between dentists and technicians. It is beneficial to the reorganization of medical and technological resources. Its potential in upgrading the dental industry deserves attention. Digitalization promotes the establishment of a collaborative and sharing ecosystem in restorative dentistry, which would pave the way towards artificial intelligence.口腔修复涉及临床诊疗流程、个性化修复体定制、医患和医技间信息传递与沟通,甚至对美学的个性理解,是一个跨学科领域。数字化修复以临床需求为牵引,目的在于优化人才与物质资源配置、提高医技工作效率、改善修复效果、提升社会经济效益。数字化战略布局对口腔行业的发展有结构性影响。本文梳理了口腔修复数字化的发展历程,通过区分狭义数字化和广义数字化两大发展阶段,指出将数字化技术作为辅助工具的片面性与局限性,强调数字化理念的战略先导作用和数字化技术的拓新能力。数字化技术助力医患沟通,促进医师与技师信息传递方式的变化,有利于医技资源重整,其在口腔产业升级方面的潜力值得重视。广义的口腔修复数字化将推动口腔修复行业协同共享生态的建立,也是通向口腔医疗智能化的必经之路。.
- Published
- 2020
5. Changes in the levels of NF-κB signaling mediators and IL-1β in rats with radiation-induced lung injury
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Z J, Shen and J H, Qiu
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Radiation Injuries, Experimental ,Interleukin-1beta ,NF-kappa B ,Animals ,Lung Injury ,Rats ,Signal Transduction - Published
- 2019
6. Characteristics of Ni/AlOx/Pt RRAM devices with various dielectric fabrication temperatures
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Ivona Z. Mitrovic, Cezhou Zhao, T Luo, Chun Zhao, Wangying Xu, Li Yang, Z J Shen, Y B Huang, and E G Lim
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010302 applied physics ,Fabrication ,Materials science ,business.industry ,Annealing (metallurgy) ,020209 energy ,02 engineering and technology ,Dielectric ,01 natural sciences ,Resistive random-access memory ,Resistive switching ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Electrical performance ,Optoelectronics ,Thin film ,business ,Voltage - Abstract
In this work, the Ni/AlO x /Pt RRAM device was fabricated with solution-processed AlO x thin film at different annealing temperatures (150/200/250/300/350°C). The supreme electrical performance and stable operation of device has been achieved demonstrating resistive switching characteristics at 250°C, including SET operation voltage lower than 1.5 V, narrowest resistance distribution, retention time longer than 104 s and endurance over 102 cycles. The results reveal the effect of dielectric fabrication temperatures for RRAM device and demonstrate the prospect of solution-processed methodology.
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- 2019
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7. Telmisartan inhibits Ang II-induced MMP-9 expression in macrophages in stabilizing atheromatous plaque
- Author
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Z-J, Shen, C-S, Xu, Y-P, Li, J, Li, J-J, Xu, and P, Xia
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Dose-Response Relationship, Drug ,Matrix Metalloproteinase 9 ,Angiotensin II ,Macrophages ,Humans ,Telmisartan ,Angiotensin II Type 1 Receptor Blockers ,Gene Expression Regulation, Enzymologic ,Plaque, Atherosclerotic ,Cell Line - Abstract
To investigate the effects of telmisartan on matrix metalloproteinase-9 (MMP-9) expression in macrophages induced by angiotensin II (Ang II) and its mechanism.THP-1 cells were adopted for research, and phorbol-12-myristate-13-acetate (PMA) was utilized to induce THP-1 cells to be transformed into macrophages, with Ang II as a stimulating factor and telmisartan as a therapeutic drug. Cell counting kit-8 (CCK8) and lactate dehydrogenase (LDH) were applied to detect cell viability and toxicity. Enzyme-linked immunosorbent assay (ELISA) was performed to measure the MMP-9 release level. Polymerase Chain Reaction (PCR) and Western blotting were conducted to detect the expressions of MMP-9 messenger ribonucleic acid (mRNA) and protein, respectively. The mechanism of action was further studied, and the activity of cyclooxygenase-2 (COX2)/macrophage-expressed gene 1 (mPEG1) pathway was determined via PCR and Western blotting.The 1 mM Ang II could remarkably activate the synthesis and release of MMP-9 as well as the COX2/mPEG1 pathway in macrophages. However, telmisartan could effectively repress the Ang II-induced MMP-9 synthesis and release in the macrophages, and suppress the COX2/mPEG1 pathway in the macrophages activated by Ang II.Telmisartan can inhibit the activation of MMP-9 in the macrophages by suppressing the COX2/mPEG1 pathway.
- Published
- 2018
8. Vrille is required for larval moulting and metamorphosis of Helicoverpa armigera (Lepidoptera: Noctuidae)
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X. Liu, S. Zhang, Z. J. Shen, Y. Liu, and Z. Li
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0106 biological sciences ,0301 basic medicine ,media_common.quotation_subject ,20-Hydroxyecdysone ,Methoprene ,Helicoverpa armigera ,Molting ,Moths ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Genetics ,Animals ,Amino Acid Sequence ,Metamorphosis ,Molecular Biology ,Phylogeny ,media_common ,Larva ,biology ,fungi ,Metamorphosis, Biological ,Gene Expression Regulation, Developmental ,biology.organism_classification ,Cell biology ,Juvenile Hormones ,010602 entomology ,030104 developmental biology ,Basic-Leucine Zipper Transcription Factors ,Ecdysterone ,chemistry ,Insect Science ,Juvenile hormone ,Insect Proteins ,Ecdysone receptor ,Moulting ,Sequence Alignment - Abstract
Vrille (Vri), a basic leucine zipper transcription factor, plays important roles in insect circadian clock regulation, tracheal development, proliferation, flight and metamorphosis. Here, Helicoverpa armigera was used as a model to investigate the role of Vri in larval moulting and metamorphosis. Sequence analysis results revealed that H. armigera Vri (HaVri) shares a high amino acid identity with other Lepidoptera Vri homologues. Spatial-temporal expression pattern data showed that HaVri expression was highly abundant in larval moulting and metamorphosis stages and was mainly expressed in the midgut and Malpighian tubule during metamorphosis. HaVri knockdown by RNA interference in the fourth-instar larvae prevented larval moulting, and HaVri knockdown in the fifth-instar larvae suppressed midgut remodelling and delayed or blocked metamorphosis. Further studies confirmed that 20-hydroxyecdysone (20E) activated HaVri expression via its heterodimer receptors, ecdysone receptor (EcRB1) and ultraspiracle protein (USP1), whereas methoprene [juvenile hormone analogue (JHA)] promoted HaVri expression via its intracellular receptor methoprene-tolerant (Met1). However, 20E and JHA can counteract each other in the activation of HaVri expression. Together, the present results suggested that HaVri was involved in larval moulting and metamorphosis and was regulated by 20E and JHA in H. armigera.
- Published
- 2018
9. Dense GaN nanocolumn arrays by hybrid top-down-regrow approach using nanosphere lithography
- Author
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Miryam Arredondo-Arechavala, Gourab Sabui, Vitaly Z. Zubialevich, Z. J. Shen, Peter J. Parbrook, Mathew McLaren, and Pietro Pampili
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Materials science ,III-V semiconductors ,Dry etching ,Annealing (metallurgy) ,Nanolithography ,Surface treatment ,Gallium nitride ,02 engineering and technology ,Semiconductor growth ,Epitaxy ,01 natural sciences ,Annealing ,GaN ,Dense nanocolumn arrays ,chemistry.chemical_compound ,0103 physical sciences ,Silica nanosphere hard masks ,Epitaxial growth ,Metalorganic vapour phase epitaxy ,Dense locally ordered 2D arrays ,010302 applied physics ,Array fill factor ,business.industry ,Thermal annealing ,Wide-bandgap semiconductor ,Gallium compounds ,Masks ,Hybrid top-down-regrow approach ,Shape ,Optics ,Nanostructured materials ,021001 nanoscience & nanotechnology ,Wide band gap semiconductors ,Nonpolar m-plane facets ,NC crystal quality ,Height deviations ,chemistry ,MOCVD ,Wet etching ,Nanosphere lithography ,Optoelectronics ,SiO2 ,0210 nano-technology ,business ,Nanocolumns - Abstract
A comprehensive description of a procedure to form dense locally ordered 2D arrays of vertically aligned hexagonal in section GaN nanocolumns (NCs) without height deviations will be presented. Particular focus will be given for the preparation of silica nanosphere hard masks, dry etching to form GaN NCs, wet etching to modify NC shape, thermal annealing and regrowth to recover non-polar m-plane facets, improve NC crystal quality and array fill factor.
- Published
- 2018
10. [Comparison of the translucency and color masking effect of the zirconia ceramics made by milling and gel deposition]
- Author
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X Y, Cui, D, Tong, X Z, Wang, and Z J, Shen
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Ceramics ,Materials Testing ,Color ,Humans ,Tooth Discoloration ,Zirconium - Abstract
Three kinds of zirconia specimens were made respectively by milling of the prisintered blocks and by three dimensional (3D) gel deposition for in vitro evaluation of their optical translucency under three different thicknesses and their color masking effect on discolored teeth. The study aims for establishing the principle for guiding the materials selection in clinical practice.Ninety A2-colored zirconia disc specimens with diameter of 14 mm were prepared and were divided into three groups (n=30). (1) Group CZ, by milling of the presintered blanks; (2) Group NZW, by 3D gel deposition, without a color masking opaque inner layer; (3) Group NZY, by 3D gel deposition, with a color masking opaque inner layer. Furthermore, each group was divided into three sub-groups (n=10) according to the sample thickness, i.e., 0.6, 1.0 and 1.5 mm, respectively. The maxillary anterior teeth with severe discoloration, extracted owing to periodontal disease, were collected and embedded. By gentle gridding and polishing a plane, larger than 6 mm2×6 mm(1) The optical transparency of the three kinds of zirconia disc specimens with the thickness of 0.6, 1.0 and 1.5 mm was 14.09, 12.31 and 10.45 for group CZ; 19.84, 16.54 and 12.44 for group NZW;14.81, 13.16 and 11.92 for group NZY. In each group, the degree of optical transparency of the specimens showed a clear tendency as in the sub-group 0.6 mm1.0 mm1.5 mm. The TP value of the specimens in the three groups with the same thickness showed a tendency of the group NZWgroup NZYgroup CZ. (2) After bonding onto the polished labial surface of the teeth, the color aberration ΔE of the specimens with the thickness of 0.6, 1.0 and 1.5 mm was calculated to be 10.77, 9.94 and 8.50 for group CZ; 6.84, 5.89 and 5.29 for group NZW; 4.16, 3.92 and 3.67 for group NZY. In each group, the color aberration of the specimens showed a clear tendency as in the sub-group 0.6 mm1.0 mm1.5 mm; the color aberration of the three groups with the same thickness was in the order of the group CZgroup NZWgroup NZY.In all the specimen groups with a fixed specimen thickness, the optical translucency of the specimen was the highest in group NZW made by 3D gel deposition, and the best color masking effect was obtained in specimens with a color masking opaque inner layer in group NZY, where a thickness of 0.6 mm was sufficient enough for obtaining the ideal color masking effect.
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- 2018
11. [The expression and significance of microtubule - driven protein KIF2A in epithelial ovarian cancer]
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Y Z, Xu, X M, Cao, Q, Ye, S, Zhang, Y Q, Zhang, and Z J, Shen
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Ovarian Neoplasms ,Kinesins ,Carcinoma, Ovarian Epithelial ,Transfection ,Microtubules ,Gene Expression Regulation, Neoplastic ,Cell Movement ,Cell Line, Tumor ,Gene Knockdown Techniques ,Humans ,Female ,Neoplasm Invasiveness ,Neoplasms, Glandular and Epithelial ,RNA, Small Interfering ,Cell Proliferation - Published
- 2017
12. Dredged fill treatment using horizontal wick drains with vibrating roller compaction
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Z. J. Shen and K. S. He
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Compaction ,Geotechnical engineering ,Geology - Published
- 2017
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13. Three-body fragmentation of CF4 3+ induced by 1 keV electron collision
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Enliang Wang, X. Zhao, L. Chen, Z. J. Shen, X. Shan, and X. J. Chen
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Physics ,History ,Fragmentation (mass spectrometry) ,Electron collision ,Molecular physics ,Computer Science Applications ,Education - Abstract
Synopsis We report the investigation on three-body fragmentation of CF4 3+ induced by 1 keV electron collision utilizing an ion momentum spectrometer. With the help of coincidence measurement for three fragment ions, the channel CF4 3+→F++CF2++F+ is identified. By employing Dalitz plot and Newton diagram, a sequential path-way and a concerted pathway are uncovered, which are further separated by momentum correlation of two F+ ions. We find that the CF4 3+ fragmentation prefers a sequential pathway CF4 3+→F++CF3 2+→F++ F++CF2 +.
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- 2020
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14. A Center Point Iteration MPPT Method With Application on the Frequency-Modulated LLC Microinverter
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Changsheng Hu, Qian Zhang, Lin Chen, Z. J. Shen, Issa Batarseh, Nasser Kutkut, and Ahmadreza Amirahmadi
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Solar micro-inverter ,Control theory ,Duty cycle ,Electrical and Electronic Engineering ,LC circuit ,Converters ,Frequency modulation ,Pulse-width modulation ,Maximum power point tracking ,Mathematics ,Power (physics) - Abstract
Maximum power point tracking (MPPT) is an essential technique to harvest PV power under varying environments. Perturb and observe (P& O) algorithms are the most broadly used MPPT due to their effectiveness and simplicity. However, it is difficult to balance the tracking speed and oscillation requirements in the conventional P& O with fixed perturb. Adaptive P& O techniques have been proposed as a solution to these problems. However, they are based on duty cycle modulation for conventional pulse width modulation converters. None of them deal with the variable frequency modulation for resonant converters. In this paper, a center point iteration MPPT is proposed, with its variable perturb in frequency. The proposed scheme overcomes the drawbacks of conventional P& O with a simple calculation. Moreover, it is suitable for various power curves, especially the LLC microinverter power curves, which may confuse conventional MPPT algorithms. The effectiveness of the proposed MPPT method was verified in theory. A 300 W prototype was constructed, and the experimental results verified the effectiveness of the proposed center point iteration MPPT. An advanced version was also introduced in order to accelerate the tracking speed.
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- 2014
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15. A Controlled-Type ZVS Technique Without Auxiliary Components for the Low Power DC/AC Inverter
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Qian Zhang, Xiang Fang, I. Bartarseh, Z. J. Shen, Dehua Zhang, and Haibing Hu
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Hysteresis ,Control theory ,Computer science ,Duty cycle ,Electronic engineering ,Inverter ,Electrical and Electronic Engineering ,Current (fluid) ,Inductor ,Network topology ,Frequency modulation ,Power (physics) - Abstract
This paper proposes a soft switching technique for dc/ac inverters, by using duty cycle and frequency modulation. Zero voltage switching (ZVS) is achieved through controlling the inductor current bidirectional in every switching cycle. This technique requires no additional resonant components and can be employed for various low power applications on conventional full-bridge and half-bridge inverter topologies. Three different current mode control schemes are derived from the basic theory of the proposed technique. They are referred to as boundary current mode (BCM), variable hysteresis current mode (VHCM), and constant hysteresis current mode (CHCM) in this paper and their advantages and disadvantages are compared. Simulation and experimental results demonstrate the feasibilities of the proposed soft-switching technique and its control schemes.
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- 2013
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16. A Three-port Flyback for PV Microinverter Applications With Power Pulsation Decoupling Capability
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Issa Batarseh, Souhib Harb, Qian Zhang, Z. J. Shen, Haibing Hu, Dehua Zhang, and Xiang Fang
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Engineering ,business.industry ,Flyback transformer ,Photovoltaic system ,Decoupling capacitor ,law.invention ,Capacitor ,Model predictive control ,Solar micro-inverter ,Film capacitor ,Control theory ,law ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Decoupling (electronics) - Abstract
A novel single-stage photovoltaic (PV) microinverter with power decoupling capability is proposed in this paper. The proposed topology is based on three-port flyback with one port dedicated to power decoupling function so as to reduce the decoupling capacitance, thus allowing for long lifetime film capacitor to be used. Operation principle is analyzed in details. Key design considerations, including key parameter selections, predictive control strategy, and the dc voltage balance control across the power decoupling capacitor, are given in this paper. A 100-W microinverter prototype is built to verify the proposed topology. Experimental results show the proposed topology can achieve power decoupling, while maintaining good efficiency.
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- 2012
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17. Distributed Battery Micro-Storage Systems Design and Operation in a Deregulated Electricity Market
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Nasser Kutkut, Issa Batarseh, Ala A. Hussein, and Z. J. Shen
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Battery (electricity) ,Engineering ,Renewable Energy, Sustainability and the Environment ,business.industry ,Electrical engineering ,Energy storage ,Automotive engineering ,Renewable energy ,Electric power system ,Stand-alone power system ,Systems design ,Electricity market ,Electricity ,business - Abstract
This paper covers some design and operation aspects of distributed battery micro-storage systems in a deregulated electricity market system. In this paper, the term “micro” refers to the size of the energy storage (ES) system compared to the grid generation, with a capacity from few kilowatt-hours and up. Generally, ES enhances the performance of renewable distributed generators (DGs) and increases the efficiency of the entire power system. Energy storage allows for leveling the load, shaving peak demands, and furthermore, transacting power with the utility grid. In this paper, different design aspects of distributed micro-storage systems are covered such as system architecture, system sizing, power stage design, battery management system (BMS), economic aspects and operation in a deregulated electricity market with and without renewable DGs.
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- 2012
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18. Methodology An improved strategy based on RAPD markers efficiently identified 95 peach cultivars
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W.Y. Wang, Jinggui Fang, Z. J. Shen, M. L. Yu, and Ruijuan Ma
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Germplasm ,fungi ,food and beverages ,General Medicine ,Biology ,RAPD ,Horticulture ,Genetic marker ,Genotype ,Botany ,Genetics ,Plant species ,Cultivar ,Molecular Biology - Abstract
DNA markers have useful applications in cultivar identification. A novel analysis approach called cultivar identification diagram (CID) was developed using DNA markers in the separation of plant individuals. This new strategy is less time- and cost-consuming, has reliable results, and was constructed for fingerprinting. Ten 11-mer primers were used to amplify the genotypes; all 95 peach genotypes (from the National Peach Germplasm Repository, in Nanjing, China) were distinguished by a combination of 54 primers. The utilization of the CID among these 95 peach cultivars was also verified by the identification of three randomly chosen groups of cultivars. This identification showed some advantages including the use of fewer primers and easy separation of all cultivars by the corresponding primers marked in the right position on the CID. This peach CID could provide the information to separate any peach cultivars of these 95, which may be of help to the peach industry in China and for the utilization of DNA markers to identify other plant species.
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- 2012
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19. Integration of a Monolithic Buck Converter Power IC and Bondwire Inductors With Ferrite Epoxy Glob Cores
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Hongwei Jia, Xuexin Wang, Karthik Padmanabhan, Z. J. Shen, and Jian Lu
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Engineering ,business.industry ,Buck converter ,Buck–boost converter ,Ćuk converter ,Electrical engineering ,Hardware_PERFORMANCEANDRELIABILITY ,Integrated circuit ,AC power ,Inductor ,law.invention ,law ,Boost converter ,Hardware_INTEGRATEDCIRCUITS ,Electronic engineering ,Ferrite (magnet) ,Electrical and Electronic Engineering ,business - Abstract
In this letter, we report a concept of integrating a monolithic buck converter power IC with in-package bondwire inductors. The power IC containing all switching devices, driver circuitry, and control logic was designed and fabricated with a standard 0.5-μm CMOS process. Mutliturn bondwires with and without ferrite epoxy glob cores are used as the filter inductor in the buck converter. A prototype system-in-package converter with an output voltage and current of 2.5 V and 120 mA was built to operate at frequencies up to 5 MHz. The power level of the prototype buck converter is scalable by increasing the size of the active power switches.
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- 2011
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20. Performance of Trench Power MOSFET With Strained Si/SiGe Multilayer Channel
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Shan Sun, Jiann-Shiun Yuan, and Z J Shen
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Materials science ,business.industry ,Transistor ,Electrical engineering ,Short-channel effect ,Electronic, Optical and Magnetic Materials ,law.invention ,Silicon-germanium ,chemistry.chemical_compound ,Strain engineering ,chemistry ,law ,Trench ,MOSFET ,Optoelectronics ,Power semiconductor device ,Electrical and Electronic Engineering ,Power MOSFET ,business - Abstract
Strain engineering such as tensile-strained silicon on silicon germanium is widely used in complementary metal-oxide-semiconductor (MOS) devices to enhance carrier mobility and can potentially reduce the specific on-resistance of trench power MOS field-effect transistors (MOSFETs). We report on the numerical study of a new trench power MOSFET structure with a strained p-type Si/SiGe superlatticelike channel region and of a process of fabricating the device. The stress distribution and the mobility enhancement inside the MOSFET structure are investigated. The breakdown voltage, the specific on-resistance, and the gate charge of the SiGe power MOSFET are evaluated. The new SiGe-channel power MOSFET exhibits a 12% reduction in the on -resistance while maintaining essentially the same blocking voltage and gate charge as the silicon trench power MOSFET.
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- 2011
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21. Design Considerations for Maintaining DC-Side Voltage of Hybrid Active Power Filter With Injection Circuit
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Zhikang Shuai, An Luo, Xianyong Xu, Z. J. Shen, and Wenji Zhu
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Rectifier ,Engineering ,business.industry ,Harmonics ,Power electronics ,Electronic engineering ,Power factor ,Electrical and Electronic Engineering ,AC power ,business ,PWM rectifier ,Active filter ,Pulse-width modulation - Abstract
Hybrid active power filter with injection circuit (IHAPF) shows great promise in reducing harmonics and improving power factor with a relatively low capacity active power filter, but suffers from DC-side voltage instability that inadvertently impacts the compensation performance and safety of the IHAPF. In this paper, two new methods are proposed to overcome this major technical challenge with a hysteretic control and energy release circuit, and a controllable pulsewidth modulation (PWM) rectifier. Modeling, theoretical analysis, and experimental results have verified that both methods can stabilize DC-side voltage within a certain range. A prototype IHAPF system was built incorporating the PWM rectifier DC voltage control scheme, and installed in a 220 kV substation in Southern China. It demonstrated significant improvement in harmonics reduction and power factor. The DC voltage stability issue was also resolved with the new design.
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- 2009
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22. Diversity, population structure, and evolution of local peach cultivars in China identified by simple sequence repeats
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Z. X. Cai, Z. J. Shen, M. L. Yu, Ruijuan Ma, and Z. Zhang
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Ecotype ,Prunus persica ,Genetic diversity ,China ,Heterozygote ,Geography ,Dendrogram ,Genetic Variation ,Locus (genetics) ,General Medicine ,Biology ,Biological Evolution ,Pedigree ,Genetics, Population ,Plant morphology ,Botany ,Ornamental plant ,Genetics ,Microsatellite ,Cultivar ,Domestication ,Molecular Biology ,Alleles ,Phylogeny ,Microsatellite Repeats - Abstract
The fruit peach originated in China and has a history of domestication of more than 4000 years. Numerous local cultivars were selected during the long course of cultivation, and a great morphological diversity exists. To study the diversity and genetic background of local peach cultivars in China, a set of 158 accessions from different ecological regions, together with 27 modern varieties and 10 wild accessions, were evaluated using 49 simple sequence repeats (SSRs) covering the peach genome. Broad diversity was also observed in local cultivars at the SSR level. A total of 648 alleles were amplified with an average of 13.22 observed alleles per locus. The number of genotypes detected ranged from 9 (UDP96015) to 58 (BPPCT008) with an average of 27.00 genotypes per marker. Eight subpopulations divided by STRUCTURE basically coincided with the dendrogram of genetic relationships and could be explained by the traditional groups. The 8 subpopulations were juicy honey peach, southwestern peach I, wild peach, Buddha peach + southwestern peach II, northern peach, southern crisp peach, ornamental peach, and Prunus davidiana + P. kansuensis. Most modern varieties carried the genetic backgrounds of juicy honey peach and southwestern peach I, while others carried diverse genetic backgrounds, indicating that local cultivars were partly used in modern breeding programs. Based on the traditional evolution pathway, a modified pathway for the development of local peach cultivars in China was proposed using the genetic background of subpopulations that were identified by SSRs. Current status and prospects of utilization of Chinese local peach cultivars were also discussed according to the SSR information.
- Published
- 2015
23. Numerical simulation of crack formation process in clays during drying and wetting
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Z. J. Shen and G. Deng
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Crack closure ,Materials science ,Consolidation (soil) ,Computer simulation ,Rotational symmetry ,Fracture mechanics ,Geotechnical engineering ,Wetting ,Drainage ,Geotechnical Engineering and Engineering Geology ,Finite element method - Abstract
Clays generally crack upon drying and the cracks gradually close up because of expansion of the clays induced by rainfall infiltration. Based on the concept of air drainage ratio, we introduce an improved simplified consolidation theory for unsaturated soils and apply it to solve the crack formation problem. We present initial conditions, special consideration, and finite-element (FEM) formulations for simulation of cracks under axisymmetric conditions. Similar to finding solutions for sand-well consolidation problems, a prism of clays surrounded by polygonal distributed cracks is simplified as a cylinder. Numerical simulations using the FEM formulations are performed on the processes of crack occurrence, propagation, and closure during drying and wetting. To investigate the influence of air drainage ratio distribution, three different schemes are adopted for computation. It is found that the behaviour of cracks in clays during drying and wetting can be well represented using the approach proposed in the ...
- Published
- 2006
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24. Prevalence and predictors of renal artery stenosis in Chinese patients with coronary artery disease
- Author
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D. S. W. Ho, Y. Q. Wang, W. F. Lam, Y. Wang, M. Chui, Z. J. Shen, C. Z. Lu, and W. H. Chen
- Subjects
medicine.medical_specialty ,business.industry ,Atherosclerotic cardiovascular disease ,food and beverages ,biochemical phenomena, metabolism, and nutrition ,medicine.disease ,Renal artery stenosis ,Nephropathy ,carbohydrates (lipids) ,Coronary artery disease ,Stenosis ,Abdominal aortogram ,medicine.artery ,Internal medicine ,Epidemiology ,Internal Medicine ,medicine ,Cardiology ,heterocyclic compounds ,lipids (amino acids, peptides, and proteins) ,Renal artery ,business - Abstract
Background: Ischaemic nephropathy is currently a major public health issue in atherosclerotic populations. Although atherosclerotic cardiovascular disease in Asia has reached epidemic proportions over the last two decades, there is little published data on the prevalence of atherosclerotic renal artery stenosis (ARAS) in Oriental subjects. Because ARAS may be clinically silent until end-stage renal failure sets in, it is important to identify patients with significant but clinically unsuspected ARAS. ARAS and coronary artery disease (CAD) often coexist. Aims: The purpose of the present study was to evaluate the prevalence and predictors of ARAS among Chinese patients with CAD. Methods: A total of 230 consecutive Chinese patients with CAD confirmed by coronary angiography underwent an abdominal aortogram in the same sitting to screen for ARAS. Patient demographics and comorbidities were analysed for any association with ARAS. Results: A total of 34 (14.8%) patients was found to have significant ARAS. Age and multivessel CAD were independent predictors of ARAS. Hypertension, renal insufficiency, extracranial cerebrovascular disease and female gender were also associated with a higher risk of ARAS but did not independently predict ARAS. Conclusion: Clinically silent yet angiographically significant ARAS is common among CAD patients. The prevalence and predictors of ARAS among Chinese patients with CAD are similar to those reported for Caucasian subjects. Underlying ARAS should be suspected in CAD patients with such comorbidities as hypertension, renal insufficiency, extracranial cerebrovascular disease, and more so in the elderly and those with multivessel disease. (Intern Med J 2003; 33: 280−285)
- Published
- 2003
- Full Text
- View/download PDF
25. Genome-wide analysis of the homeodomain-leucine zipper (HD-ZIP) gene family in peach (Prunus persica)
- Author
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Nicholas Kibet Korir, Z J Shen, M L Yu, Ruijuan Ma, Xuming Sun, and C H Zhang
- Subjects
Candidate gene ,Leucine zipper ,Subfamily ,Arabidopsis ,Biology ,Exon ,Gene Expression Regulation, Plant ,Genetics ,Gene family ,Molecular Biology ,Gene ,health care economics and organizations ,Phylogeny ,Homeodomain Proteins ,Leucine Zippers ,fungi ,Protein primary structure ,Intron ,General Medicine ,Multigene Family ,population characteristics ,Prunus ,human activities ,Genome, Plant ,Transcription Factors - Abstract
In this study, 33 homeodomain-leucine zipper (HD-ZIP) genes were identified in peach using the HD-ZIP amino acid sequences of Arabidopsis thaliana as a probe. Based on the phylogenetic analysis and the individual gene or protein characteristics, the HD-ZIP gene family in peach can be classified into 4 subfamilies, HD-ZIP I, II, III, and IV, containing 14, 7, 4, and 8 members, respectively. The most closely related peach HD-ZIP members within the same subfamilies shared very similar gene structure in terms of either intron/exon numbers or lengths. Almost all members of the same subfamily shared common motif compositions, thereby implying that the HD-ZIP proteins within the same subfamily may have functional similarity. The 33 peach HD-ZIP genes were distributed across scaffolds 1 to 7. Although the primary structure varied among HD-ZIP family proteins, their tertiary structures were similar. The results from this study will be useful in selecting candidate genes from specific subfamilies for functional analysis.
- Published
- 2014
26. ELECTROSTATIC CHARGING OF TEXTILES
- Author
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Z. J. Shen, J. E. McIntyre, and I. Holme
- Subjects
Materials science ,General Chemical Engineering ,General Materials Science ,Industrial and Manufacturing Engineering - Published
- 1998
- Full Text
- View/download PDF
27. Surface modification of molten W exposed to high heat flux helium neutral beams
- Author
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B. Böswirth, H. Greuner, G.-N. Luo, Baoqin Fu, Wenguan Liu, Ch. Linsmeier, Hongxia Xu, Y. Yuan, and Z. J. Shen
- Subjects
Nuclear and High Energy Physics ,Solid-state chemistry ,Materials science ,Metallurgy ,Analytical chemistry ,chemistry.chemical_element ,Flux ,Tungsten ,Fluence ,Nuclear Energy and Engineering ,chemistry ,Heat flux ,Surface modification ,General Materials Science ,Irradiation ,Helium - Abstract
High heat flux tests with central heat flux of 10.5 MW/m 2 using helium neutral beams have been carried out on rolled tungsten. The energy of helium particles is 33 keV and the particle flux is 2 × 10 21 m −2 s −1 . An 80 × 65 × 3 mm 3 rolled tungsten plate is firstly exposed to a 4.6 s pulse resulting in partially molten surfaces. Thereafter the tungsten plate is irradiated by several helium pulses with fluences of 1.2–2.5 × 10 22 /m 2 and peak temperatures from 1450 to 2590 °C. The experiments show that: (1) helium-induced surface modification of the resolidified tungsten surface is very different from that of the non-molten surface; (2) the surface morphology of molten surface is closely related to the orientation of the resolidified grain; (3) the evolution of surface modifications, for both of the molten and non-molten tungsten surfaces, indicates a strong dependence on the surface temperature and local helium fluence.
- Published
- 2013
28. The research on particle trajectory of solid-liquid two-phase flow and erosion predicting in screw centrifugal pump
- Author
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W G Zhao, Ren Nian Li, Z J Shen, X H Wang, and W Han
- Subjects
Materials science ,Internal flow ,Mechanical engineering ,02 engineering and technology ,Volute ,Mechanics ,Centrifugal pump ,01 natural sciences ,Slip factor ,010305 fluids & plasmas ,Physics::Fluid Dynamics ,Impeller ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Phase (matter) ,0103 physical sciences ,Particle ,Two-phase flow - Abstract
Use the Discrete Phase Model (DPM) based on Euler-Lagrange method, the internal flow field of screw centrifugal pump was simulated by computational fluid dynamics(CFD) code when transmission medium is solid-liquid two phase flow with large-size particles. The research of liquid phase is under the Euler coordinate system while the solid phase is under the Lagrange coordinate system. The energy change, trajectory characteristic of solid phase particle and its erosion damage rule of solid-phase particle in whole computational domain is analyzed with different density, partical size(d=0.05mm, d=0.2mm, d=2mm) and solid volume fraction(Cv=3%, Cv=5%, Cv=7%).The result shows that within a given diameter range, the low density fine particles trajectory are longer, more collision times with flow passage components, more energy loss and the erosion parts are relatively uniform, but particles which are large-size diameter and high density has a big collision angle with the surface of impeller and volute, even the area of impact and abrasion are quite focus, and easy to be transported. particles will impact with the head of impeller when it enter into impeller domain, the erosion mainly occurs on the work side of impeller.
- Published
- 2016
- Full Text
- View/download PDF
29. An improved strategy based on RAPD markers efficiently identified 95 peach cultivars
- Author
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M L, Yu, W Y, Wang, R J, Ma, Z J, Shen, and J G, Fang
- Subjects
Genetic Markers ,Base Sequence ,DNA, Plant ,Prunus ,DNA Primers ,Random Amplified Polymorphic DNA Technique - Abstract
DNA markers have useful applications in cultivar identification. A novel analysis approach called cultivar identification diagram (CID) was developed using DNA markers in the separation of plant individuals. This new strategy is less time- and cost-consuming, has reliable results, and was constructed for fingerprinting. Ten 11-mer primers were used to amplify the genotypes; all 95 peach genotypes (from the National Peach Germplasm Repository, in Nanjing, China) were distinguished by a combination of 54 primers. The utilization of the CID among these 95 peach cultivars was also verified by the identification of three randomly chosen groups of cultivars. This identification showed some advantages including the use of fewer primers and easy separation of all cultivars by the corresponding primers marked in the right position on the CID. This peach CID could provide the information to separate any peach cultivars of these 95, which may be of help to the peach industry in China and for the utilization of DNA markers to identify other plant species.
- Published
- 2012
30. Effect of the electron–surface-optical-phonon interaction on the impurity-state energies in a semiconductor quantum well
- Author
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G. T. Shen, Z. J. Shen, B. C. Yang, and X. Z. Yuan
- Subjects
Condensed Matter::Quantum Gases ,Physics ,Potential well ,Condensed matter physics ,Condensed Matter::Other ,Phonon ,Energy level splitting ,Binding energy ,Interaction energy ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter::Superconductivity ,Atom ,Principal quantum number ,Condensed Matter::Strongly Correlated Electrons ,Atomic physics ,Quantum well - Abstract
Using a variational technique, the change of ground-state energy and binding energy of an impurity atom with impurity position and well width in a GaAs-${\mathrm{Ga}}_{0.7}$${\mathrm{Al}}_{0.3}$As quantum well is calculated. In the calculation the electron--surface-optical-phonon interactions are taken into account. The result is discussed. It is found that the electron-phonon interaction energy depends not only on the width of the well but also on the position of the impurity atom in the well.
- Published
- 1994
- Full Text
- View/download PDF
31. Oxygen absorption in a baffled tank agitated by delta paddle impeller
- Author
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Malcolm H. I. Baird, N. V. Rama Rao, and Z. J. Shen
- Subjects
Impeller ,Gas velocity ,Volume (thermodynamics) ,Power consumption ,Chemistry ,General Chemical Engineering ,Oxygen absorption ,Analytical chemistry ,Thermodynamics ,Paddle ,Oxygen uptake ,Rushton turbine - Abstract
The power consumption and the volume-based mass transfer coefficient (kla) for oxygen uptake from air into water have been measured for delta paddle impellers (10 cm and 20 cm diameter) in water in a 30 cm square sectioned baffled tank. Power consumption under ungassed conditions was measured in viscous mineral oil. For the 20 cm impeller, the effects of minor design modifications, such as sweeping the blade forward or back, have also been examined. The power numbers are approximately 2.0 in the absence of sparged gas, but are reduced by over 50% when gas is supplied beneath the impeller. Mass transfer data can be correlated with the power input per unit volume and the superficial gas velocity, showing that the performance with aeration of water is comparable to that reported by previous workers for the Rushton turbine impeller. La consommation ďenergie et le coefficient de transfert de matiere base sur le volume (kla) pour ľabsorption ďoxygene de ľair dans ľeau ont ete mesures pour des turbines a ailettes delta (diametre de 10 et de 20 cm) dans ľeau dans un reservoir a chicanes de sections carrees de 30 cm. La consommation ďenergie dans des conditions sans gaz a ete mesuree dans de ľhuile minerale visqueuse. Pour la turbine de 20 cm, on a egalement examine les effets des legeres modifications apportees dans la conception, par exemple dans le balayage des aubes (avant ou arriere). Les nombres de puissance sont approximativement de 2,0 en ľabsence de gaz, mais se trouvent reduits de 50% lorsq'on ajoute du gaz sous la turbine. Les donnees de transfert de matiere peuvent ětre correlees a ľapport ďenergie par unite de volume et a la vitessse de gaz superficielle, ce qui montre que la performance avec ľaeration de ľeau est comparable a celle qui est mentionnee dans les travaux anterieurs sur les turbines Rushton.
- Published
- 1993
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- View/download PDF
32. ChemInform Abstract: Duplex α,β-Sialon Ceramics Stabilized by Dysprosium and Samarium
- Author
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T. Ekstroem, Lena K. L. Falk, and Z.‐J. Shen
- Subjects
Sialon ,Samarium ,Lanthanide ,Crystallography ,chemistry ,Duplex (building) ,visual_art ,Dysprosium ,visual_art.visual_art_medium ,chemistry.chemical_element ,General Medicine ,Ceramic - Published
- 2010
- Full Text
- View/download PDF
33. Progress on the Investigation of Coal-Water Slurry Fuel Combustion in a Medium-Speed Diesel Engine: Part 5—Combustion Studies
- Author
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Z. J. Shen, G. L. Confer, and B. D. Hsu
- Subjects
Engineering ,Thermal efficiency ,Waste management ,business.industry ,Mechanical Engineering ,Energy Engineering and Power Technology ,Aerospace Engineering ,Diesel cycle ,Coal-water slurry fuel ,Diesel engine ,Fuel injection ,Diesel fuel ,Fuel Technology ,Nuclear Energy and Engineering ,Internal combustion engine ,Thrust specific fuel consumption ,business - Abstract
This paper reports that in the GE 7FDL single-cylinder research diesel engine, coal-water slurry (CWS) fuel combustion optimization studies were conducted using electronically controlled CWS and pilot accumulator injectors. The most important performance parameters of peak firing pressure, combustion efficiency (coal burnout) and specific fuel consumption were evaluated in relationship to CWS and pilot injection timing, CWS injector hole size, shape, and number, CWS fuel injection spray angles and injection pressure. Heat release diagrams, as well as exhaust samples (gaseous and particulate), were analyzed for each case. Interesting effects of fuel spray impingement and CWS fuel Delayed Ignition were observed. With the engine operating at 2.0 MPa IMEP and 1050 rpm, it was able to obtain over 99.5 percent combustion efficiency while holding the cylinder firing pressure below 17 MPa and thermal efficiency equivalent to diesel fuel operation.
- Published
- 1992
- Full Text
- View/download PDF
34. Exploration for the Cause of Damage of a Pile-Supported Pier
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Z-J Shen, R-L Wei, and Y Dou
- Subjects
Pier ,Engineering ,business.industry ,Geotechnical engineering ,Deformation (meteorology) ,business ,Pile - Published
- 2008
- Full Text
- View/download PDF
35. Experimental Study on the Mechanical Behavior and Destructured Process of Artificially, Structured Soils in Triaxial Compression
- Author
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E. L. Liu and Z. J. Shen
- Subjects
Materials science ,Scientific method ,Soil water ,Composite material ,Triaxial compression - Published
- 2006
- Full Text
- View/download PDF
36. Progress in Binary Medium Modeling of Geological Materials
- Author
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Z.-J. Shen
- Subjects
Representative elementary volume ,Binary number ,Mineralogy ,Geological materials ,Vertical Strain ,Geology - Published
- 2006
- Full Text
- View/download PDF
37. [Evaluation of clinical application of intravascular ultrasound image]
- Author
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W L, Zhu, C L, Huang, D, Han, Z J, Shen, and Y, Zeng
- Subjects
Adult ,Male ,Evaluation Studies as Topic ,Humans ,Female ,Coronary Artery Disease ,Prospective Studies ,Middle Aged ,Coronary Angiography ,Ultrasonography, Interventional ,Aged - Abstract
To prospectively evaluate the clinical applications of intravascular ultrasound (IVUS).Four hundred and thirty seven patients with coronary artery disease (CAD) or suspect CAD were imaged with CAD and IVUS, including (1) assessment IVUS in 135 cases with normal coronary angiography (CAG) (2) comparison IVUS with CAG pre and after angioplasty in 52 patients with CAD (3) assessment of detecting calcification lesions with CAG and IVUS in 150 patients (4) predicting the cardiac events after stent implantation guided by IVUS (n = 47) and CAG (N = 53).IVUS may detect coronary atherosclerosis lesions with normal by CAG. CAG overestimated effect of angioplasty. IVUS was more accurate to determine effect and complications of PTCA compared with CAG. IVUS interpreted the mechanism of vessel dilatation in PTCA. The cardiac events after stent implantation were significantly reduced after IVUS examination as compared with CAG.IVUS represents a radically different approach to vascular anatomy. Unlike angiography, which displays the coronary artery as a silhouette of the contrast-filled lumen, IVUS generates a cross-sectional tomographic image of the lumen and vessel wall. IVUS plays an important role as a guidance in cardiac intervention.
- Published
- 2003
38. Prevalence and predictors of renal artery stenosis in Chinese patients with coronary artery disease
- Author
-
Y, Wang, D S W, Ho, W H, Chen, Y Q, Wang, W F, Lam, Z J, Shen, C Z, Lu, and M, Chui
- Subjects
Male ,Analysis of Variance ,Angiography ,Comorbidity ,Coronary Artery Disease ,Middle Aged ,Coronary Angiography ,Prognosis ,Renal Artery Obstruction ,Severity of Illness Index ,Cohort Studies ,Survival Rate ,Age Distribution ,Logistic Models ,Asian People ,Predictive Value of Tests ,Risk Factors ,Prevalence ,Hong Kong ,Humans ,Female ,Sex Distribution ,Aged ,Probability - Abstract
Ischaemic nephropathy is currently a major public health issue in atherosclerotic populations. Although atherosclerotic cardiovascular disease in Asia has reached epidemic proportions over the last two decades, there is little published data on the prevalence of atherosclerotic renal artery stenosis (ARAS) in Oriental subjects. Because ARAS may be clinically silent until end-stage renal failure sets in, it is important to identify patients with significant but clinically unsuspected ARAS. ARAS and coronary artery disease (CAD) often coexist.The purpose of the present study was to evaluate the prevalence and predictors of ARAS among Chinese patients with CAD.A total of 230 consecutive Chinese patients with CAD confirmed by coronary angiography underwent an abdominal aortogram in the same sitting to screen for ARAS. Patient demographics and comorbidities were analysed for any association with ARAS.A total of 34 (14.8%) patients was found to have significant ARAS. Age and multivessel CAD were independent predictors of ARAS. Hypertension, renal insufficiency, extracranial cerebrovascular disease and female gender were also associated with a higher risk of ARAS but did not independently predict ARAS.Clinically silent yet angiographically significant ARAS is common among CAD patients. The prevalence and predictors of ARAS among Chinese patients with CAD are similar to those reported for Caucasian subjects. Underlying ARAS should be suspected in CAD patients with such comorbidities as hypertension, renal insufficiency, extracranial cerebrovascular disease, and more so in the elderly and those with multivessel disease.
- Published
- 2003
39. Effect of aging on penile ultrastructure
- Author
-
Z J, Shen, X D, Jin, Z D, Chen, and Y H, Shi
- Subjects
Male ,Rats, Sprague-Dawley ,Aging ,Erectile Dysfunction ,Microscopy, Electron, Scanning ,Animals ,Humans ,Muscle, Smooth ,Elastic Tissue ,Penis ,Rats - Abstract
To clarify whether there are anatomical changes in tunica albuginea and corpora cavemosa in aged rats.Seventeen male Sprague-Dawley rats were divided into three groups based on age. Group A consisted of young rats (9 weeks), Group B, middle aged rats (14 weeks) and Group C, old rats (62 weeks). The penile samples were obtained and observed under a scanning electron microscope.The thickness (mean +/- SD) of the tunica albuginea was 0.14 +/- 0.02, 0.16 +/- 0.03 and 0.06 +/- 0.02 mm in Groups A, B and C, respectively. The tunica albuginea of group C was significantly thinner than those of the other two groups (P0.05) and the elastic fibers were diminished in the old rats. In the corpora cavernosa of old rats, the intracavernous pillars were irregular, in which many large collagen fibers could be observed, and the smooth muscle and elastic fibers were reduced.In old rats, the tunica albuginea became thinner with diminished elastic fibers; the collagen fibers of corpora cavernosa were increased while the smooth muscle and elastic fibers were reduced.
- Published
- 2001
40. The value of endotoxin concentrations in expressed prostatic secretions for the diagnosis and classification of chronic prostatitis
- Author
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L J, Li, Z J, Shen, Y L, Lu, and S Z, Fu
- Subjects
Adult ,Endotoxins ,Male ,Chronic Disease ,Prostate ,Humans ,Bacterial Infections ,Middle Aged ,Sensitivity and Specificity ,Prostatitis - Abstract
To clarify the value of endotoxin concentrations in expressed prostatic secretions (EPS) in the diagnosis and classification of chronic prostatitis.The study included 88 consecutive patients with chronic prostatitis and 15 controls with no urological disease. The diagnosis and classification were based on a history, symptoms, a digital rectal examination of the prostate, and a white blood cell count in the EPS. Endotoxin concentrations in the EPS or urine were measured using a colorimetric assay and standard microbiological methods used to identify bacterial growth.In men with chronic prostatitis caused by Gram-negative or combined Gram-negative and -positive bacteria, the endotoxin levels in urine collected immediately after prostatic massage were significantly greater (P0.01) than in a midstream urine sample, and the concentration in the EPS was significantly higher (P0.05) than that in the control group. The same was true of patients with chronic prostatitis and Gram-positive bacteria isolated from the EPS or urine after massage. In patients with chronic pelvic pain syndrome (grade IIIA) the endotoxin level in the urine after massage was also significantly higher (P0.05) than that of the midstream sample, but there was no significant difference between the concentration in these samples in patients with grade IIIB, and no significant difference between the endotoxin concentration of the EPS in patients with grade IIIB and that in controls.Endotoxin concentrations are increased in the EPS or urine (after prostatic massage) of men with bacterial chronic prostatitis or chronic pelvic pain syndrome grade IIIA. The current routine examinations (including bacterial culture and routine examination of EPS or urine) before diagnosis and classification of chronic prostatitis are insufficient to describe the cause and pathogenesis of this condition. The endotoxin concentration of the EPS or urine after massage may provide a supplementary tool to identify the cause of chronic prostatitis.
- Published
- 2001
41. FLASH coordinates NF-kappa B activity via TRAF2
- Author
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Y H, Choi, K B, Kim, H H, Kim, G S, Hong, Y K, Kwon, C W, Chung, Y M, Park, Z J, Shen, B J, Kim, S Y, Lee, and Y K, Jung
- Subjects
Tumor Necrosis Factor-alpha ,Blotting, Western ,Calcium-Binding Proteins ,NF-kappa B ,Proteins ,Oligonucleotides, Antisense ,Protein Serine-Threonine Kinases ,TNF Receptor-Associated Factor 2 ,Peptide Mapping ,I-kappa B Kinase ,Jurkat Cells ,Structure-Activity Relationship ,Animals ,Humans ,Rabbits ,Apoptosis Regulatory Proteins ,Promoter Regions, Genetic - Abstract
FLASH is a protein recently shown to interact with the death effector domain of caspase-8 and is likely to be a component of the death-inducing signaling complex in receptor-mediated apoptosis. Here we show that antisense oligonucleotide-induced inhibition of FLASH expression abolished TNF-alpha-induced activation of NF-kappaB in HEK293 cells, as determined by luciferase reporter gene expression driven by a NF-kappaB responsive promoter. Conversely, overexpression of FLASH dose-dependently activated NF-kappaB, an effect suppressed by dominant negative mutants of TRAF2, NIK, and IKKalpha, and partially by those of TRAF5 and TRAF6. TRAF2 was co-immunoprecipitated with FLASH from the cell extracts of HEK293 cells or HeLa cells stably expressing exogenous FLASH (HeLa/HA-FLASH). Furthermore, serial deletion mapping demonstrated that a domain spanning the residues 856-1191 of FLASH activated NF-kappaB as efficiently as the full-length and could directly bind to TRAF2 in vitro and in the transfected cells. Taken together, these results suggest that FLASH coordinates downstream NF-kappaB activity via a TRAF2-dependent pathway in the TNF-alpha signaling.
- Published
- 2001
42. Specific inhibition of transforming growth factor-beta2 expression in human osteoblast cells by antisense phosphorothioate oligonucleotides
- Author
-
Z J, Shen, S K, Kim, O S, Kwon, Y S, Lee, and B J, Moon
- Subjects
Osteoblasts ,Time Factors ,Dose-Response Relationship, Drug ,Blotting, Western ,Enzyme-Linked Immunosorbent Assay ,Oligonucleotides, Antisense ,Blotting, Northern ,Lipid Metabolism ,Lipids ,Cell Line ,Transforming Growth Factor beta2 ,Transforming Growth Factor beta ,Humans ,Indicators and Reagents ,Cation Exchange Resins ,RNA, Messenger ,Codon ,Cell Division - Abstract
To elucidate the role of endogenous transforming growth factor (TGF)-beta2 on human osteoblast cell, antisense phosphorothioate oligonucleotides (S-ODNs) complementary to regions in mRNA of TGF-beta2 were synthesized and examined their effects on TGF-beta2 production and cell proliferation in a human osteoblast cell line ROS 17/2. Antisense S-ODNs were designated for three different target regions in the mRNA of TGF-beta2. Among several antisense S-ODN analyzed, an oligonucleotide (AS-11) complementary to the translation initiation site of mRNA of TGF-beta2 demonstrated a selective and strong inhibitory effect on TGF-beta2 production in osteoblast cells. Other antisense S-ODNs which were designated for other regions in mRNA of TGF-beta2 and one- or three-base mismatched analogs of AS-11 showed little or much less antisense activities than AS-11. Therefore, the most effective target site in mRNA of TGF-beta2 is at the initiation codon region. The antisense effects of AS-11 were observed without reduction of levels of mRNA of TGF-beta2. Furthermore, the inhibition of TGF-beta2 expression by antisense S-ODN appeared to enhance cell proliferation, demonstrating the growth inhibitory effect of autocrine TGF-beta2 in osteoblast cells.
- Published
- 2001
43. ChoICE PT wire for recanalization of chronically occluded coronary arteries: multiple wires in one?
- Author
-
D S, Ho, R Y, Zhang, M, Waser, Z J, Shen, Y, Wang, and P, Ouyang
- Subjects
Adult ,Aged, 80 and over ,Male ,Equipment Safety ,Coronary Disease ,Equipment Design ,Middle Aged ,Coronary Angiography ,Treatment Outcome ,Chronic Disease ,Humans ,Female ,Angioplasty, Balloon, Coronary ,Aged ,Follow-Up Studies - Abstract
Percutaneous transluminal coronary angioplasty (PTCA) of chronic total occlusions may be technically difficult and the success rate is limited despite increasing operator experience and improvements in PTCA hardware. The number of guidewires required to cross totally occluded lesions is higher than that for stenotic lesions. The ChoICE polymer-tip (PT) wire (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) is a relatively new stainless-steel core wire with a hydrophilic-coated polyurethane tip. Though never described in the literature, we found that the distal 4 cm of the wire can be cut and reshaped according to the operator's needs. Thus, instead of reshaping a kinked tip or using another new wire, the former being time-consuming and the latter expensive, one can simply cut off the kinked tip and start again with a "new wire." As the tip is resected, the wire becomes progressively more "intermediate-like" and "standard-like." We report our experience with the ChoICE PT wire in 50 consecutive cases of chronic total occlusions. The cumulative crossing success rates were 13/50 (26%) before any resections, 24/50 (48%) after 1 resection, 41/50 (82%) after 2 resections and 42/50 (84%) after 3 resections. There were no perforations, deaths, myocardial infarctions or need for bypass surgery. Our findings suggest that successful recanalization of chronic total occlusions can be achieved with a high success rate using the ChoICE PT wire. A strategy of progressively resecting the more floppy and kinked distal end can provide multiple uses from a single wire, optimizing recanalization success and obviating the need for additional wires.
- Published
- 2000
44. Effects of androgen and ageing on gene expression of vasoactive intestinal polypeptide in rat corpus cavernosum
- Author
-
Z J, Shen, Y L, Lu, Z D, Chen, F, Chen, and Z, Chen
- Subjects
Male ,Rats, Sprague-Dawley ,Aging ,Animals ,Gene Expression ,Dihydrotestosterone ,Testosterone ,RNA, Messenger ,Penis ,Rats ,Vasoactive Intestinal Peptide - Abstract
To clarify the effects of androgens (testosterone and dihydrotestosterone, DHT) and ageing on gene expression of vasoactive intestinal polypeptide (VIP), assessed as the expression of VIP mRNA, in rat corpus cavernosum. Materials and methods The study comprised 160 male Sprague Dawley rats divided into group A (56 rats, 5 weeks old), group B (50 rats, 10 weeks old) and group C (54 rats, 58 weeks old). Groups A-C were subdivided, respectively, into subgroups 1 (intact controls), 2 (castrated), 3 (castrated but given testosterone undecanoate 25 mg/kg per month by intramuscular injection), 4 (castrated with testosterone undecanoate 50 mg/kg per month) and 5 (treated with finasteride 4.5 mg/kg per day, orally). At 4 and 10 weeks after these treatments half the rats were killed. Serum samples were taken for the measurement of total and free testosterone and DHT, using a radioimmunoassay. Penile samples (corpus cavernosum) were frozen in liquid nitrogen and stored at -80 degrees C. VIP mRNA was estimated using a semi-quantitative reverse-transcription polymerase chain reaction.There was no significant difference in VIP mRNA in rat corpus cavernosum between intact control and castrated subgroups, or subgroups treated with finasteride, in groups A-C, including both the 4- and 10-week old animals (P0.05). Penile VIP mRNA was unchanged at any dose of testosterone in the castrated subgroups in all groups (P0.05). There was no significant relationship between penile VIP mRNA and ageing (P0.05).The gene expression of VIP in rat corpus cavernosum is independent of androgens (testosterone and DHT) and ageing. Androgens probably induce penile erection by pathways other than VIP; ageing may have little effect on penile VIP mRNA.
- Published
- 2000
45. Thermophysical properties of multi-shock compressed dense argon
- Author
-
Z. J. Shen, Jie Zheng, Y. L. Chen, Qi-Feng Chen, Ling-Cang Cai, and Y. J. Gu
- Subjects
Dense plasma focus ,Argon ,General Physics and Astronomy ,chemistry.chemical_element ,Atmospheric-pressure plasma ,Computational physics ,law.invention ,Shock (mechanics) ,chemistry ,law ,Light-gas gun ,Plasma diagnostics ,Particle velocity ,Physical and Theoretical Chemistry ,Atomic physics ,Pyrometer - Abstract
In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ∼6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.
- Published
- 2014
- Full Text
- View/download PDF
46. Research on energy conversion mechanism of a screw centrifugal pump under the water
- Author
-
Q M Su, Z J Shen, Rennian Li, Xiao Rui Cheng, Quan Hui, and Wei Han
- Subjects
Engineering ,business.industry ,Internal flow ,Mechanical engineering ,Total dynamic head ,Centrifugal pump ,Slip factor ,Computer Science::Robotics ,Physics::Fluid Dynamics ,Impeller ,Rotodynamic pump ,Energy transformation ,Shroud ,business - Abstract
In order to research screw centrifugal pump impeller power capability and energy conversion mechanism, we used Navier-Stokes equation and standard k-e equation turbulence model on the basis of the Euler equations to carry out screw centrifugal pump internal flow numerical simulation. This was explored by simulating specific design conditions; the medium is water, variation of speed and pressure of flow filed under the action of the impeller, and the screw centrifugal impeller shroud line and wheel line segment take monitoring sites. The monitoring points are between dynamic head and static head change to analyze the energy conversion capability along the impeller corners of screw centrifugal pump. The results show that the energy of fluid of the screw centrifugal pump is provided by spiral segment, the spiral segment in front of the impeller has played a multi-level role, it has significant reference value to research the energy conversion mechanism of screw centrifugal pump under solid-liquid two phase.
- Published
- 2013
- Full Text
- View/download PDF
47. Study on solid-liquid two-phase unsteady flow characteristics with different flow rates in screw centrifugal pump
- Author
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H Y Wang, Z J Shen, W Ma, Wei Han, and Rennian Li
- Subjects
Physics::Fluid Dynamics ,Impeller ,Materials science ,Flow (mathematics) ,Multiphase flow ,Fluent ,Radius ,Volute ,Mechanics ,Centrifugal pump ,Simulation ,Volumetric flow rate - Abstract
The screw centrifugal pump is used as an object, and the unsteady numerical simulation of solid-liquid two-phase flow is carried out under different flow rate conditions in one circle by choosing the two-phase flow of sand and water as medium, using the software FLUENT based on the URANS equations, combining with sliding mesh method, and choosing the Mixture multiphase flow model and the SIMPLE algorithm. The results show that, with the flow rate increasing, the change trends for the pressure on volute outlet are almost constant, the fluctuation trends of the impeller axial force have a little change, the pressure and the axial force turn to decrease on the whole, the radial force gradually increases when the impeller maximum radius passes by half a cycle near the volute outlet, and the radial force gradually decreases when the maximum radius passes by the other half a cycle in a rotation cycle. The distributions of the solid particles are very uneven under a small flow rate condition on the face. The solid particles under a big flow rate condition are distributed more evenly than the ones under a small flow rate condition on the back. The theoretical basis and reference are provided for improving its working performance.
- Published
- 2013
- Full Text
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48. Numerical analysis of the internal flow field in screw centrifugal blood pump based on CFD
- Author
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Z J Shen, B X Han, Wei Han, and H Y Wang
- Subjects
Blood pump ,Impeller ,Materials science ,Internal flow ,Turbulence ,Rotodynamic pump ,Shear force ,Mechanical engineering ,Progressive cavity pump ,Centrifugal pump - Abstract
As to the impeller blood pump, the high speed of the impeller, the local high shear force of the flow field and the flow dead region are the main reasons for blood damage. The screw centrifugal pump can effectively alleviate the problems of the high speed and the high shear stress for the impeller. The softness and non-destructiveness during the transfer process can effectively reduce the extent of the damage. By using CFD software, the characteristics of internal flow are analyzed in the screw centrifugal pump by exploring the distribution rules of the velocity, pressure and shear deformation rate of the blood when it flows through the impeller and the destructive effects of spiral blades on blood. The results show that: the design of magnetic levitation solves the sealing problems; the design of regurgitation holes solves the problem of the flow dead zone; the magnetic levitated microcirculation screw centrifugal pump can effectively avoid the vortex, turbulence and high shear forces generated while the blood is flowing through the pump. Since the distribution rules in the velocity field, pressure field and shear deformation rate of the blood in the blood pump are comparatively uniform and the gradient change is comparatively small, the blood damage is effectively reduced.
- Published
- 2013
- Full Text
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49. Injection-type hybrid active power filter in high-power grid with background harmonic voltage
- Author
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Chuanping Wu, Z. J. Shen, An Luo, and W Zhao
- Subjects
Engineering ,Switched-mode power supply ,business.industry ,Power factor ,Voltage optimisation ,AC power ,Control theory ,Harmonics ,Harmonic ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Active filter ,Voltage - Abstract
In this study, an injection type hybrid active power filter (IHAPF) and its correlative key techniques are researched. Furthermore, the influences on IHAPF made by background harmonic voltage in power grid are analysed in detail. The IHAPF using the proposed recursive integral controller and harmonic detection method can not only mitigate harmonic ip−iq currents but also compensate high-capacity reactive power. Nevertheless, background harmonic voltage in power grid may damage IHAPF because it may lead to resonance and sharp rise of DC-link voltage. Two methods, which are parameter designs for avoiding resonance and hysteresis control for eliminating sharp rise of DC-link voltage, have been proposed to restrain the influences. The system realisation of IHAPF is introduced. Industry application results have confirmed the validity of the IHAPF and the methods to restrain the influences caused by background harmonic voltage.
- Published
- 2011
- Full Text
- View/download PDF
50. Effect of an image potential on the ground-state energy of shallow-donor impurities near the surface of semi-infinite crystals
- Author
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Yaochun Shen, B. C. Yang, Z. J. Shen, and X. Z. Yuan
- Subjects
Materials science ,Semi-infinite ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Molecular physics ,Ionized impurity scattering ,Crystal ,symbols.namesake ,Impurity ,Condensed Matter::Superconductivity ,symbols ,Condensed Matter::Strongly Correlated Electrons ,Hamiltonian (quantum mechanics) ,Ground state ,Shallow donor ,Elliptic coordinate system - Abstract
The effect of image potential on the ground-state energy of a shallow-donor impurity near a sharp surface of a semi-infinite crystal is studied. A simple but realistic trial function is used in the confocal elliptic coordinate system with the foci at the hydrogenic donor impurity and its image point. The groundstate energy of this system is calculated as a function of the impurity position
- Published
- 1993
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