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Authors = Zhe Zhang ORCID = 0000-0001-5708-3159

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ZHE (196) , ZHANG (7473)

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Open AccessArticle Research on Capacitance Current Compensation Scheme of Current Differential Protection of Complex Four-Circuit Transmission Lines on the Same Tower
Energies 2017, 10(7), 1071; doi:10.3390/en10071071
Received: 19 June 2017 / Revised: 10 July 2017 / Accepted: 19 July 2017 / Published: 23 July 2017
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Abstract
Current differential protection is the main protection of transmission lines which include multi-circuit lines on the same tower, and whose sensitivity and reliability of differential protection is mainly affected by the distributed capacitive current. For the four-circuit line on the same tower, due
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Current differential protection is the main protection of transmission lines which include multi-circuit lines on the same tower, and whose sensitivity and reliability of differential protection is mainly affected by the distributed capacitive current. For the four-circuit line on the same tower, due to the influence of coupling between the loop road, the distributed capacitance current increases significantly when compared with ordinary lines, affecting the sensitivity of the current differential protection, especially for different voltage levels throughout the four-circuit lines on the same tower. The relationship of the electrostatic coupling between the circuits is more complex, and increases the difficulty of the compensating the distributed capacitance current. This paper is based on the electrostatic coupling principle of four-circuit lines on the same tower, establishes the distributed parameter model of four-circuit transmission lines on the same tower, and discusses the effect of circuit operation mode on the compensation of capacitance current differential protection when different faults occur on the complex four-circuit transmission lines on the same tower. A new compensation scheme suitable for capacitive current compensation is proposed. Simulation results show that this capacitive current compensation scheme can effectively improve the performance of current differential protection. Full article
(This article belongs to the Section Electrical Power and Energy System)
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Open AccessArticle Relationship between Forest Color Characteristics and Scenic Beauty: Case Study Analyzing Pictures of Mountainous Forests at Sloped Positions in Jiuzhai Valley, China
Forests 2017, 8(3), 63; doi:10.3390/f8030063
Received: 15 January 2017 / Revised: 20 February 2017 / Accepted: 24 February 2017 / Published: 28 February 2017
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Abstract
Forests are important place for outdoor recreation and scenery appreciation. So in order to better meet the needs of the public, forest appreciation has received increasing attention from foresters in recent years. However, related research is still limited. Therefore, this paper seeks to
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Forests are important place for outdoor recreation and scenery appreciation. So in order to better meet the needs of the public, forest appreciation has received increasing attention from foresters in recent years. However, related research is still limited. Therefore, this paper seeks to examine the relationship between forest colors (measured by specific elements and spatial indices of color) and Scenic Beauty Estimation values. We researched Jiuzhai Valley in China by selecting 104 pictures to determine the scenic beauty estimation values of forests in a mountainous region. Quantitative color elements were extracted by programming on Matlab, and spatial indices of color patches were extracted by ArcGIS and FRAGSTATS. A total of 23 indices were obtained to explain the color characteristics of each forest picture. The results showed that the yellow and red colors were the main mutable colors of Jiuzhai Valley in autumn, but the color patches index had no significant change over time in that season. After partial correlation analysis, principal component analysis, and cluster analysis, we found that 14 color elements, eight color patch factors and six particular indices had an effect on the SBE values, which can then be used to efficiently measure and enhance the forest color beauty of Jiuzhai Valley. Full article
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Open AccessArticle Optimization Design of Coupling Beam Metal Damper in Shear Wall Structures
Appl. Sci. 2017, 7(2), 137; doi:10.3390/app7020137
Received: 10 November 2016 / Revised: 25 December 2016 / Accepted: 22 January 2017 / Published: 3 February 2017
Cited by 1 | Viewed by 453 | PDF Full-text (2362 KB) | HTML Full-text | XML Full-text
Abstract
The coupling beam damper is a fundamental energy dissipation component in coupling shear wall structures that directly influences the performance of the shear wall. Here, we proposed a two-fold design method that can give better energy dissipation performance and hysteretic behavior to coupling
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The coupling beam damper is a fundamental energy dissipation component in coupling shear wall structures that directly influences the performance of the shear wall. Here, we proposed a two-fold design method that can give better energy dissipation performance and hysteretic behavior to coupling beam dampers. First, we devised four in-plane yielding coupling beam dampers that have different opening types but the same amount of total materials. Then the geometry parameters of each opening type were optimized to yield the maximum hysteretic energy. The search for the optimal parameter set was realized by implementing the Kriging surrogate model which iterates randomly selected input shape parameters and the corresponding hysteretic energy calculated by the infinite element method. By comparing the maximum hysteretic energy in all four opening types, one type that had the highest hysteresis energy was selected as the optimized design. This optimized damper has the advantages of having a simple geometry and a high dissipation energy performance. The proposed method also provided a new framework for the design of in-plane coupling beam dampers. Full article
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Open AccessArticle Serum Metabolomic Profiling Identifies Characterization of Non-Obstructive Azoospermic Men
Int. J. Mol. Sci. 2017, 18(2), 238; doi:10.3390/ijms18020238
Received: 9 November 2016 / Revised: 10 January 2017 / Accepted: 12 January 2017 / Published: 25 January 2017
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Abstract
Male infertility is considered a common health problem, and non-obstructive azoospermia with unclear pathogenesis is one of the most challenging tasks for clinicians. The objective of this study was to investigate the differential serum metabolic pattern in non-obstructive azoospermic men and to determine
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Male infertility is considered a common health problem, and non-obstructive azoospermia with unclear pathogenesis is one of the most challenging tasks for clinicians. The objective of this study was to investigate the differential serum metabolic pattern in non-obstructive azoospermic men and to determine potential biomarkers related to spermatogenic dysfunction. Serum samples from patients with non-obstructive azoospermia (n = 22) and healthy controls (n = 31) were examined using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Serum metabolomic profiling could differentiate non-obstructive azoospermic patients from healthy control subjects. A total of 24 metabolites were screened and identified as potential markers, many of which are involved in energy production, oxidative stress and cell apoptosis in spermatogenesis. Moreover, the results showed that various metabolic pathways, including d-glutamine and d-glutamate metabolism, taurine and hypotaurine metabolism, pyruvate metabolism, the citrate cycle and alanine, aspartate and glutamate metabolism, were disrupted in patients with non-obstructive azoospermia. Our results indicated that the serum metabolic disorders may contribute to the etiology of non-obstructive azoospermia. This study suggested that serum metabolomics could identify unique metabolic patterns of non-obstructive azoospermia and provide novel insights into the pathogenesis underlying male infertility. Full article
(This article belongs to the Special Issue Molecular Research on Urology)
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Open AccessArticle Communication Channel Reconstruction for Transmission Line Differential Protection: System Arrangement and Routing Protocol
Energies 2016, 9(11), 893; doi:10.3390/en9110893
Received: 31 July 2016 / Revised: 27 September 2016 / Accepted: 17 October 2016 / Published: 29 October 2016
Cited by 1 | Viewed by 474 | PDF Full-text (4758 KB) | HTML Full-text | XML Full-text
Abstract
Natural disasters may be of significant impact on overhead transmission lines and cause communication outage related to pilot protection. This paper aims at reconstructing communication channels and maintaining functions of pilot-wire differential protections after the main channel fails. With the development of smart
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Natural disasters may be of significant impact on overhead transmission lines and cause communication outage related to pilot protection. This paper aims at reconstructing communication channels and maintaining functions of pilot-wire differential protections after the main channel fails. With the development of smart grids as well as new communication technologies, wireless sensor networks (WSNs) have been potential means for realizing reconstructed communication channels (RCCs) without further installation. For a reliable design, system arrangement and the communication structure were presented. Theoretical planning of sensor nodes was formulated, which enjoys advantages such as high reliability, cost optimization, and capacity of satisfying the connectivity of the communication network. To meet the need of time delay, a novel routing protocol for WSNs was proposed with three stages including route establishment, route discovery and route maintenance, which ensured the directional propagation of data packets. Practical experiments and simulation results indicate that the proposed RCC scheme can satisfy time delay of protection relaying in emergency communication channel, as well as guarantee the connectivity of networks when some WSN nodes are damaged. Full article
(This article belongs to the Special Issue Advances in Power System Operations and Planning)
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Open AccessArticle Gene Expression Profiles of Main Olfactory Epithelium in Adenylyl Cyclase 3 Knockout Mice
Int. J. Mol. Sci. 2015, 16(12), 28320-28333; doi:10.3390/ijms161226107
Received: 15 August 2015 / Revised: 13 November 2015 / Accepted: 17 November 2015 / Published: 30 November 2015
Cited by 2 | Viewed by 1171 | PDF Full-text (1296 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Adenylyl Cyclase 3 (AC3) plays an important role in the olfactory sensation-signaling pathway in mice. AC3 deficiency leads to defects in olfaction. However, it is still unknown whether AC3 deficiency affects gene expression or olfactory signal transduction pathways within the main
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Adenylyl Cyclase 3 (AC3) plays an important role in the olfactory sensation-signaling pathway in mice. AC3 deficiency leads to defects in olfaction. However, it is still unknown whether AC3 deficiency affects gene expression or olfactory signal transduction pathways within the main olfactory epithelium (MOE). In this study, gene microarrays were used to screen differentially expressed genes in MOE from AC3 knockout (AC3−/−) and wild-type (AC3+/+) mice. The differentially expressed genes identified were subjected to bioinformatic analysis and verified by qRT-PCR. Gene expression in the MOE from AC3−/− mice was significantly altered, compared to AC3+/+ mice. Of the 41266 gene probes, 3379 had greater than 2-fold fold change in expression levels between AC3−/− and AC3+/+ mice, accounting for 8% of the total gene probes. Of these genes, 1391 were up regulated, and 1988 were down regulated, including 425 olfactory receptor genes, 99 genes that are specifically expressed in the immature olfactory neurons, 305 genes that are specifically expressed in the mature olfactory neurons, and 155 genes that are involved in epigenetic regulation. Quantitative RT-PCR verification of the differentially expressed epigenetic regulation related genes, olfactory receptors, ion transporter related genes, neuron development and differentiation related genes, lipid metabolism and membrane protein transport etc. related genes showed that P75NTR, Hinfp, Gadd45b, and Tet3 were significantly up-regulated, while Olfr370, Olfr1414, Olfr1208, Golf, Faim2, Tsg101, Mapk10, Actl6b, H2BE, ATF5, Kirrrel2, OMP, Drd2 etc. were significantly down-regulated. In summary, AC3 may play a role in proximal olfactory signaling and play a role in the regulation of differentially expressed genes in mouse MOE. Full article
(This article belongs to the Section Biochemistry, Molecular and Cellular Biology)
Open AccessArticle The Functions of BMP3 in Rabbit Articular Cartilage Repair
Int. J. Mol. Sci. 2015, 16(11), 25934-25946; doi:10.3390/ijms161125937
Received: 4 September 2015 / Revised: 30 September 2015 / Accepted: 21 October 2015 / Published: 29 October 2015
Cited by 1 | Viewed by 1108 | PDF Full-text (10322 KB) | HTML Full-text | XML Full-text
Abstract
Bone morphogenetic proteins (BMPs) play important roles in skeletal development and repair. Previously, we found fibroblast growth factor 2 (FGF2) induced up-regulation of BMP2, 3, 4 in the process of rabbit articular cartilage repair, which resulted in satisfactory repair effects. As BMP2/4 show
[...] Read more.
Bone morphogenetic proteins (BMPs) play important roles in skeletal development and repair. Previously, we found fibroblast growth factor 2 (FGF2) induced up-regulation of BMP2, 3, 4 in the process of rabbit articular cartilage repair, which resulted in satisfactory repair effects. As BMP2/4 show a clearly positive effect for cartilage repair, we investigated the functions of BMP3 in rabbit articular cartilage repair. In this paper, we find that BMP3 inhibits the repair of partial-thickness defect of articular cartilage in rabbit by inducing the degradation of extracellular matrix, interfering with the survival of chondrocytes surrounding the defect, and directly inhibiting the expression of BMP2 and BMP4. Meanwhile BMP3 suppress the repair of full-thickness cartilage defect by destroying the subchondral bone through modulating the proliferation and differentiation of bone marrow stem cells (BMSCs), and directly increasing the expression of BMP4. Although BMP3 has different functions in the repair of partial and full-thickness defects of articular cartilage in rabbit, the regulation of BMP expression is involved in both of them. Together with our previous findings, we suggest the regulation of the BMP signaling pathway by BMP3 is essential in articular cartilage repair. Full article
(This article belongs to the Special Issue Molecular and Cellular Basis of Regeneration and Tissue Repair)
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Open AccessArticle Fault Current Characteristics of the DFIG under Asymmetrical Fault Conditions
Energies 2015, 8(10), 10971-10992; doi:10.3390/en81010971
Received: 20 July 2015 / Revised: 7 September 2015 / Accepted: 16 September 2015 / Published: 30 September 2015
Cited by 4 | Viewed by 827 | PDF Full-text (397 KB) | HTML Full-text | XML Full-text
Abstract
During non-severe fault conditions, crowbar protection is not activated and the rotor windings of a doubly-fed induction generator (DFIG) are excited by the AC/DC/AC converter. Meanwhile, under asymmetrical fault conditions, the electrical variables oscillate at twice the grid frequency in synchronous dq frame.
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During non-severe fault conditions, crowbar protection is not activated and the rotor windings of a doubly-fed induction generator (DFIG) are excited by the AC/DC/AC converter. Meanwhile, under asymmetrical fault conditions, the electrical variables oscillate at twice the grid frequency in synchronous dq frame. In the engineering practice, notch filters are usually used to extract the positive and negative sequence components. In these cases, the dynamic response of a rotor-side converter (RSC) and the notch filters have a large influence on the fault current characteristics of the DFIG. In this paper, the influence of the notch filters on the proportional integral (PI) parameters is discussed and the simplified calculation models of the rotor current are established. Then, the dynamic performance of the stator flux linkage under asymmetrical fault conditions is also analyzed. Based on this, the fault characteristics of the stator current under asymmetrical fault conditions are studied and the corresponding analytical expressions of the stator fault current are obtained. Finally, digital simulation results validate the analytical results. The research results are helpful to meet the requirements of a practical short-circuit calculation and the construction of a relaying protection system for the power grid with penetration of DFIGs. Full article
(This article belongs to the collection Wind Turbines)
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Open AccessArticle Endoplasmic Reticulum Stress Cooperates in Zearalenone-Induced Cell Death of RAW 264.7 Macrophages
Int. J. Mol. Sci. 2015, 16(8), 19780-19795; doi:10.3390/ijms160819780
Received: 8 May 2015 / Revised: 13 July 2015 / Accepted: 14 July 2015 / Published: 20 August 2015
Cited by 7 | Viewed by 1183 | PDF Full-text (5788 KB) | HTML Full-text | XML Full-text
Abstract
Zearalenone (ZEA) is a fungal mycotoxin that causes cell apoptosis and necrosis. However, little is known about the molecular mechanisms of ZEA toxicity. The objective of this study was to explore the effects of ZEA on the proliferation and apoptosis of RAW 264.7
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Zearalenone (ZEA) is a fungal mycotoxin that causes cell apoptosis and necrosis. However, little is known about the molecular mechanisms of ZEA toxicity. The objective of this study was to explore the effects of ZEA on the proliferation and apoptosis of RAW 264.7 macrophages and to uncover the signaling pathway underlying the cytotoxicity of ZEA in RAW 264.7 macrophages. This study demonstrates that the endoplasmic reticulum (ER) stress pathway cooperated in ZEA-induced cell death of the RAW 264.7 macrophages. Our results show that ZEA treatment reduced the viability of RAW 264.7 macrophages in a dose- and time-dependent manner as shown by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (MTT) and flow cytometry assay. Western blots analysis revealed that ZEA increased the expression of glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP), two ER stress-related marker genes. Furthermore, treating the cells with the ER stress inhibitors 4-phenylbutyrate (4-PBA) or knocking down CHOP, using lentivirus encoded short hairpin interfering RNAs (shRNAs), significantly diminished the ZEA-induced increases in GRP78 and CHOP, and cell death. In summary, our results suggest that ZEA induces the apoptosis and necrosis of RAW 264.7 macrophages in a dose- and time-dependent manner via the ER stress pathway in which the activation of CHOP plays a critical role. Full article
(This article belongs to the Special Issue Modulators of Endoplasmic Reticulum Stress)
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Open AccessArticle Biodegradability and Biocompatibility Study of Poly(Chitosan-g-lactic Acid) Scaffolds
Molecules 2012, 17(3), 3243-3258; doi:10.3390/molecules17033243
Received: 6 February 2012 / Revised: 26 February 2012 / Accepted: 12 March 2012 / Published: 14 March 2012
Cited by 20 | Viewed by 2649 | PDF Full-text (942 KB)
Abstract
A biodegradable, biocompatible poly(chitosan-g-lactic acid) (PCLA) scaffold was prepared and evaluated in vitro and in vivo. The PCLA scaffold was obtained by grafting lactic acid (LA) onto the amino groups on chitosan (CS) without a catalyst. The PCLA scaffolds were
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A biodegradable, biocompatible poly(chitosan-g-lactic acid) (PCLA) scaffold was prepared and evaluated in vitro and in vivo. The PCLA scaffold was obtained by grafting lactic acid (LA) onto the amino groups on chitosan (CS) without a catalyst. The PCLA scaffolds were characterized by Fourier Transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The biodegradabilty was determined by mass loss in vitro, and degradation in vivo as a function of feed ratio of LA/CS. Bone marrow mesenchymal stem cell (BMSC) culture experiments and histological examination were performed to evaluate the PCLA scaffolds’ biocompatibility. The results indicated that PCLA was promising for tissue engineering application. Full article

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