bluuebunny/crossref_metadata_2025 huggingface dataset:
Crosslinked PVA/SSA proton exchange membranes: correlation between physiochemical properties and free volume determined by positron annihilation spectroscopy
Authors: Gomaa Mahmoud M. , Hugenschmidt Christoph , Dickmann Marcel , Abdel-Hady Esam E. , Mohamed Hamdy F. M. , Abdel-Hamed Mohamed O.
Published: October 2018

At low humidity (<30 RH%), water molecules begin to fill the intermolecular spaces in the membrane. At high humidity (80 RH%) the membrane swells; the free volume size increases.
Simulation of the Raman spectroscopy of multi-layered carbon nanomaterials
Authors: Tailor Pritesh M. , Wheatley Richard J. , Besley Nicholas A.
Published: October 2018

A empirical potential based model for simulating the Raman spectroscopy of layered carbon nanomaterials is introduced.
Two-dimensional-related catalytic materials for solar-driven conversion of COx into valuable chemical feedstocks
Authors: Zhao Yufei , Waterhouse Geoffrey I. N. , Chen Guangbo , Xiong Xuyang , Wu Li-Zhu , Tung Chen-Ho , Zhang Tierui
Published: October 2018

This review summarizes recent development relating to 2D materials and their derivatives for solar-driven CO2 reduction by H2O or H2, as well as CO hydrogenation (via the water gas shift reaction or Fischer–Tropsch synthesis) to produce valuable products (especially hydrocarbons, alcohols and aromatics).
Elucidating the mechanism of the UiO-66-catalyzed sulfide oxidation: activity and selectivity enhancements through changes in the node coordination environment and solvent
Authors: Limvorapitux Rungmai , Chen Haoyuan , Mendonca Matthew L. , Liu Mengtan , Snurr Randall Q. , Nguyen SonBinh T.
Published: October 2018

“Open” sites on the nodes of UiO-66 are converted to catalytically active Zr-OOH and can coordinate with solvent/products.
Effect of acidity and ruthenium species on catalytic performance of ruthenium catalysts for acetylene hydrochlorination
Authors: Wang Xiaolong , Lan Guojun , Liu Huazhang , Zhu Yihan , Li Ying
Published: October 2018

Carbon-supported ruthenium catalysts are promising mercury-free catalysts for acetylene hydrochlorination, due to their high activity and relatively low price. The deactivation mechanism was identified and solved by a simple ammonia treated method.
Halide and substituent dependent structural variation in copper(i) halide complexes of 1,5,9-triphosphacyclododecanes
Authors: Wickramatunga Lenali V. , Pothupitiya Thusith K. , Chevalier Edith , Kariuki Benson M. , Liyanage Sudantha S. , Newman Paul D. , Edwards Peter G.
Published: October 2018

Mono- or dimeric structures of Cu(i) complexes of 12aneP3 macrocycles are obtained depending on the nature of the secondary halide ligand.
Historical and projected improvements in net energy performance of power generation technologies
Authors: Steffen Bjarne , Hischier Dominique , Schmidt Tobias S.
Published: October 2018

Energetic learning curves are presented to show how EROIs of power generation technologies improve as more capacity is installed.
The decarbonisation of petroleum and other fossil hydrocarbon fuels for the facile production and safe storage of hydrogen
Authors: Jie Xiangyu , Gonzalez-Cortes Sergio , Xiao Tiancun , Yao Benzhen , Wang Jiale , Slocombe Daniel R. , Fang Yiwen , Miller Noah , Al-Megren Hamid A. , Dilworth Jonathan R. , Thomas John M. , Edwards Peter P.
Published: October 2018

Microwave-stimulated catalytic dehydrogenation of fossil hydrocarbon fuels allows for the rapid production and safe storage of hydrogen.
The effects of resveratrol supplementation on biomarkers of inflammation and oxidative stress among patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials
Authors: Tabrizi Reza , Tamtaji Omid Reza , Lankarani Kamran B. , Mirhosseini Naghmeh , Akbari Maryam , Dadgostar Ehsan , Peymani Payam , Asemi Zatollah
Published: October 2018

The effect of resveratrol supplementation on biomarkers of inflammation and oxidative stress among patients with metabolic syndrome are controversial.
Influence of hydrocolloids (galactomannan and xanthan gum) on the physicochemical and sensory characteristics of gluten-free cakes based on fava beans (Phaseolus lunatus)
Authors: Andrade F. J. E. T. , Albuquerque P. B. S. , Moraes G. M. D. , Farias M. D. P. , Teixeira-Sá D. M. A. , Vicente A. A. , Carneiro-da-Cunha M. G.
Published: October 2018

Most gluten-free bakery formulations have starch sources of low nutritional value.
Alginate oligosaccharide alleviates enterotoxigenicEscherichia coli-induced intestinal mucosal disruption in weaned pigs
Authors: Wan Jin , Zhang Jiao , Chen Daiwen , Yu Bing , Mao Xiangbing , Zheng Ping , Yu Jie , Huang Zhiqing , Luo Junqiu , Luo Yuheng , He Jun
Published: October 2018

Alginate oligosaccharide (AOS) is a non-toxic, non-immunogenic, non-carcinogenic and biodegradable product generated by depolymerisation of alginate, and exhibits various salutary properties.
In silicoassessment and structural characterization of antioxidant peptides from major yolk protein of sea urchinStrongylocentrotus nudus
Authors: Shang Wen-Hui , Tang Yue , Su Sheng-Yi , Han Jia-Run , Yan Jia-Nan , Wu Hai-Tao , Zhu Bei-Wei
Published: October 2018

Sea urchin gonads have been demonstrated to contain major yolk protein (MYP), which can be hydrolyzed by enzymes to release biologically active peptides.
Improving the colloidal and sensory properties of a caseinate hydrolysate using particular exopeptidases
Authors: Ewert Jacob , Schlierenkamp Felix , Nesensohn Lena , Fischer Lutz , Stressler Timo
Published: October 2018

Depending on the exopeptidase specificity, properties of a technofunctional casein hydrolysate like hydrophobicity, colloidal behavior and taste are further improved.
Formation of tin-based crystals from a SnAgCu alloy under formic acid vapor
Authors: Conti Fosca , Hanss Alexander , Mokhtari Omid , Bhogaraju Sri Krishna , Elger Gordon
Published: October 2018

A new method is developed to crystallize tin formates in a formic acid-enriched nitrogen atmosphere. The SAC alloy is used.
Mechanisms of (photo)toxicity of TiO2nanomaterials (NM103, NM104, NM105): using high-throughput gene expression inEnchytraeus crypticus
Authors: Gomes Susana I. L. , Roca Carlos P. , von der Kammer Frank , Scott-Fordsmand Janeck J. , Amorim Mónica J. B.
Published: October 2018

The photoactivity of TiO2plays a major role in TiO2toxicity, triggering specific mechanisms of response.
Incorporation of Cu–Nx cofactors into graphene encapsulated Co as biomimetic electrocatalysts for efficient oxygen reduction
Authors: Yang Yang , Wang Changlai , Gao Shiqi , Mao Kaitian , Xia Guoliang , Lin Zhiyu , Jiang Peng , Hu Lin , Chen Qianwang
Published: October 2018

Atomic Cu–Nx cofactors are incorporated within graphene encapsulated Co by direct annealing of MOFs and exhibit excellent ORR activity.
Improved photovoltaic performance of perovskite solar cells based on three-dimensional rutile TiO2 nanodendrite array film
Authors: Chen Chi , Wu Shufang , Wang Jinming , Chen Siyao , Peng Tianyou , Li Renjie
Published: October 2018

A rutile TiO2 nanodendrite array (3D-RTNDA) containing trunks and branches as transport layer is fabricated for high-performance perovskite solar cells.
One-scan fluorescence emission difference nanoscopy developed with excitation orthogonalized upconversion nanoparticles
Authors: Huang Bingru , Wu Qiusheng , Peng Xingyun , Yao Liqin , Peng Dengfeng , Zhan Qiuqiang
Published: October 2018

We experimentally realized one-scan fluorescence emission difference nanoscopy (FED) by simultaneously imaging two different color emissions of NaYF4:Er3+@NaYF4@NaYF4:Yb3+/Tm3+ upconversion nanoparticles.
Design of smart targeted and responsive drug delivery systems with enhanced antibacterial properties
Authors: Chen Hao , Jin Yingying , Wang Jingjie , Wang Yuqin , Jiang Wenya , Dai Hangdong , Pang Shuaiyue , Lei Lei , Ji Jian , Wang Bailiang
Published: October 2018

The use of antibiotics has been an epoch-making invention in the past few decades for the treatment of infectious diseases.
Phosphine-free engineering toward the synthesis of metal telluride nanocrystals: the role of a Te precursor coordinated at room temperature
Authors: Wu Min , Wang Yixuan , Wang Hongyu , Wang Hao , Sui Yongming , Du Fei , Yang Xinyi , Zou Bo
Published: October 2018

We developed a new phosphine-free strategy for fabricating high-quality metal telluride nanocrystals (NCs) by using a highly reactive Te precursor coordinated at room temperature. These metal telluride NCs with good optical properties possess excellent application prospects.
Porphyrin–ferrocene conjugates for photodynamic and chemodynamic therapy
Authors: Lei Zhitao , Zhang Xiaoyu , Zheng Xiaohua , Liu Shi , Xie Zhigang
Published: October 2018

Porphyrin–ferrocene conjugates were designed and synthesized for photodynamic and chemodynamic therapy.
Photolatent ring-opening metathesis polymerization in miniemulsion: a powerful approach to produce polynorbornene latexes
Authors: Pichavant Loïc , Lacroix-Desmazes Patrick , Chemtob Abraham , Pinaud Julien , Héroguez Valérie
Published: October 2018

The use of miniemulsion Ring-Opening Metathesis Polymerization (ROMP) to form polyunsaturated latexes is still a largely unexplored field.
A versatile synthetic platform for amphiphilic nanogels with tunable hydrophobicity
Authors: Gruber Alexandra , Işık Doğuş , Fontanezi Bianca Bueno , Böttcher Christoph , Schäfer-Korting Monika , Klinger Daniel
Published: October 2018

Functionalization of reactive precursor particles allows the preparation of amphiphilic nanogel libraries with tunable network hydrophobicity and comparable colloidal features.
Iron-catalyzed alkynylation of tertiary aliphatic amines with 1-iodoalkynes to synthesize propargylamines
Authors: Ma Lina , Shi Xiaolin , Li Xiaowei , Shi Dayong
Published: October 2018

An alkynylation of tertiary aliphatic amines with 1-iodoalkynes has been developed in the presence of FeCl2 as a catalyst and tert-butyl hydroperoxide as an oxidant.
Nα-arylsulfonyl histamines as selective β-glucosidase inhibitors
Authors: Salazar M. O. , Osella M. I. , Ramallo I. A. , Furlan R. L. E.
Published: October 2018

A selective β-glucosidase inhibitor was discovered using the chemically engineered extracts approach.
Vivid colours in hyperuniform complex-index photonic structures by resonant interference of photonic band gaps and optical band gaps
Authors: Seo Chunhee , Hyon Jinho , Suk Soyeon , Oh Changjoon , Nam Jihye , Minh Duong Nguyen , Sim Jae Hyun , Kang Youngjong
Published: October 2018

Hyperuniform photonic structures (HPSs) have been doped with complex index materials to increase their reflectivity and colour expression range.
Preparation of novel phosphorus-nitrogen-silicone grafted graphene oxide and its synergistic effect on intumescent flame-retardant polypropylene composites
Authors: Yuan Gaowei , Yang Bing , Chen Yinghong , Jia Yinggang
Published: October 2018

The combination of PMGO and IFR significantly improves the flame retardancy and surface hydrophobicity of PP materials.
Electrochemiluminescence of gold nanoparticles and gold nanoparticle-labelled antibodies as co-reactants
Authors: Zhao Changzhi , Niu Lulu , Wang Xiaoyu , Sun Wei
Published: October 2018

A new electrochemiluminescence system was discovered by combining electrochemiluminescence and AuNP-labelling technology based on electrochemiluminescence of AuNPs as a co-reactant.
Cyclodextrin-based complex coacervate core micelles with tuneable supramolecular host–guest, metal-to-ligand and charge interactions
Authors: Facciotti Camilla , Saggiomo Vittorio , Bunschoten Anton , Fokkink Remco , Hove Jan Bart ten , Wang Junyou , Velders Aldrik H.
Published: October 2018

Supramolecular interactions allow fine tuning of the charge of coordination complexes, with concomitant control over size and stability of cyclodextrin-based complex coacervate core micelles.
Temperature effects on the nanoindentation characterization of stiffness gradients in confined polymers
Authors: Song Jake , Kahraman Rıdvan , Collinson David W. , Xia Wenjie , Brinson L. Catherine , Keten Sinan
Published: October 2018

Stiffness gradients in geometrically confined polymers as measured by nanoindentation are influenced by opposing roles of the polymers viscoelastic state and the degree of confinement.
Wall friction and Janssen effect in the solidification of suspensions
Authors: Saint-Michel Brice , Georgelin Marc , Deville Sylvain , Pocheau Alain
Published: October 2018

Janssen effect on a compact layer of particles formed ahead of the solidification front of a freezing suspension.
Controlled synthesis of Pt nanoparticle supported TiO2 nanorods as efficient and stable electrocatalysts for the oxygen reduction reaction
Authors: Murphin Kumar Paskalis Sahaya , Ponnusamy Vinoth Kumar , Deepthi Koolath Ramakrishnan , Kumar Gopalakrishnan , Pugazhendhi Arivalagan , Abe Hideki , Thiripuranthagan Sivakumar , Pal Umapada , Krishnan Siva Kumar
Published: October 2018

Green fabrication of TiO2 nanorods supported PtNPs for durable electrocatalysts toward oxygen reduction reaction (ORR).
Microwave-aided synthesis of lithium thiophosphate solid electrolyte
Authors: Suto Koji , Bonnick Patrick , Nagai Erika , Niitani Keita , Arthur Timothy S. , Muldoon John
Published: October 2018

Solid electrolyte synthesis: as easy as microwaving your dinner!
Interplay between the metal-support interaction and stability in Pt/Co3O4(111) model catalysts
Authors: Lykhach Yaroslava , Faisal Firas , Skála Tomáš , Neitzel Armin , Tsud Nataliya , Vorokhta Mykhailo , Dvořák Filip , Beranová Klára , Kosto Yuliia , Prince Kevin C. , Matolín Vladimír , Libuda Jörg
Published: October 2018

Metal-support interactions at the Pt/Co3O4(111) interface yield Ptδ+ species which control the stability of the supported nanoparticles.
A new strategy for the construction of 3D TiO2 nanowires/reduced graphene oxide for high-performance lithium/sodium batteries
Authors: Yu Jiage , Huang Hui , Gan Yongping , Xia Yang , Liang Chu , Zhang Jun , Tao Xinyong , Zhang Wenkui
Published: October 2018

Building a rational nanoarchitecture of TiO2 nanowires/RGO composite is a promising method to satisfy the demands of excellent Li+/Na+ storage performance.
Colloidal Ni–Co–Sn nanoparticles as efficient electrocatalysts for the methanol oxidation reaction
Authors: Li Junshan , Luo Zhishan , He Feng , Zuo Yong , Zhang Chaoqi , Liu Junfeng , Yu Xiaoting , Du Ruifeng , Zhang Ting , Infante-Carrió Maria F. , Tang Pengyi , Arbiol Jordi , Llorca Jordi , Cabot Andreu
Published: October 2018

Ni–Co–Sn alloys show improved performance toward the methanol oxidation reaction in alkaline media.
Sewing machine stitching of polyvinylidene fluoride fibers: programmable textile patterns for wearable triboelectric sensors
Authors: Shin Young-Eun , Lee Jeong-Eun , Park Yoojeong , Hwang Sang-Ha , Chae Han Gi , Ko Hyunhyub
Published: October 2018

Textile-based sensors can perceive and respond to environmental stimuli in daily life, and hence are critical components of wearable devices.
An Ångström-level d-spacing controlling synthetic route for MoS2 towards stable intercalation of sodium ions
Authors: Zhang Kan , Li Ping , Guo Shiying , Jeong Jong Yeob , Jin Bingjun , Li Xiaoming , Zhang Shengli , Zeng Haibo , Park Jong Hyeok
Published: October 2018

An optimal d-spacing of vertically aligned MoS2 arrays for stable intercalation of sodium ions is reported.
A mechanically strong and sensitive CNT/rGO–CNF carbon aerogel for piezoresistive sensors
Authors: Peng Xinwen , Wu Kunze , Hu Yijie , Zhuo Hao , Chen Zehong , Jing Shuangshuang , Liu Qingzhong , Liu Chuanfu , Zhong Linxin
Published: October 2018

A mechanically strong, sensitive and lightweight CNT/rGO–CNF carbon aerogel is fabricated by synergistic assembly of CNFs and CNTs to form ordered wave-shaped rGO layers and reinforcing the carbon layers.
Graphitic porous carbon: efficient synthesis by a combustion method and application as a highly selective biosensor
Authors: Chen Bisang , Chen Dejian , Li Feiming , Lin Xiaofeng , Huang Qitong
Published: October 2018

Efficient synthesis of graphitic porous carbon by combustion method for the simultaneous determination of uric acid and dopamine.
Simultaneous near-infrared and green fluorescence from single conjugated polymer dots with aggregation-induced emission fluorogen for cell imaging
Authors: Chen Sitong , Cui Shuang , Du Rongxin , Liu Ming , Tsai Wei-Kai , Guo Fengyun , Wu Qiong , Zhao Liancheng , Zhang Yong
Published: October 2018

Highly fluorescent conjugated polymer dots with aggregation-induced emission fluorogen were applied in in vitro and in vivo cell imaging.
Single-mode lasing and 3D confinement from perovskite micro-cubic cavity
Authors: Zhou Beier , Dong Hongxing , Jiang Mingming , Zheng Weihao , Sun Liaoxin , Zhao Binbin , Tang Bing , Pan Anlian , Zhang Long
Published: October 2018

Single-mode lasing with extreme narrow linewidth of 0.064 nm is achieved based on 3D CsPbBr3 microcube laser under room temperature.
Low-temperature combustion synthesis and UV treatment processed p-type Li:NiOx active semiconductors for high-performance electronics
Authors: Yang Jun , Wang Bowen , Zhang Yongpeng , Ding Xingwei , Zhang Jianhua
Published: October 2018

The p-type Li:NiOx thin films were successfully fabricated through the SUV route at 150 °C.
Association between Cyclin D1 G870A (rs9344) polymorphism and cancer risk in Indian population: meta-analysis and trial sequential analysis
Authors: Thakur Nisha , Kumari Suchitra , Mehrotra Ravi
Published: October 2018

Introduction: Association between Cyclin D1 (CCND1) single nucleotide polymorphism (SNP) rs9344 and cancer risk is paradoxical. Thus, we performed a meta-analysis to explore the association between CCND1 variant and overall cancer risk in Indian population. Methods: Data from 12 published studies including 3739 subjects were collected using Pubmed and Embase. RevMan (Review Manager) 5.3 was used to perform the meta-analysis. OR with 95%CI were calculated to establish the association. Results: Overall, the cumulative findings demonstrated that CCND1 polymorphism (rs9344) was not significantly associated with cancer risk in all the genetic models studied (dominant model: GG vs GA+AA: OR (95%CI) = 0.81 (0.60–1.09), P=0.17; recessive model: GG+GA vs AA: OR (95%CI) = 1.23 (0.96–1.59), P=0.11; co-dominant model: GG vs AA: OR (95%CI) = 1.35 (0.93–1.97), P=0.12; co-dominant model: (GG vs GA: OR (95%CI) = 1.16 (0.85–1.59), P=0.34; allelic model: A vs G: OR (95%CI) = 1.20 (1.14–2.85), P=0.23; allelic model: G vs A: OR (95%CI) = 0.83 (0.62–1.12), P=0.23). Subgroup analysis according to cancer types presented significant association of CCND1 polymorphism and increased breast cancer risk in dominant model (GG vs GA+AA: OR = 2.75, 95%CI = 1.54–4.90, P=0.0006) and allelic model (G vs A: OR = 1.63, 95%CI = 1.22–2.19, P=0.001). An increased esophageal cancer risk in recessive model (GG+GA vs AA: OR = 1.51, 95%CI = 1.05–2.16, P=0.03) and co-dominant model (GG vs AA: OR = 2.51, 95%CI = 1.10–5.71, P=0.03) was detected. A higher risk for colorectal cancer was detected under both the co-dominant models (GG vs AA: OR = 2.46, 95%CI = 1.34–4.51, P=0.004 and GG vs GA: OR = 1.74, 95%CI = 1.14–2.67, P=0.01). However, in case of cervical cancer risk a non-significant association was reported under the recessive model (GG+GA vs AA: OR = 1.52, 95%CI = 0.60–3.90, P=0.38) with reference to CCND1 polymorphism (rs9344). The trial sequential analysis (TSA) showed that the cumulative Z-curve neither crossed the trial sequential monitoring boundary nor reached the required information size (RIS). Thus, present meta-analysis remained inconclusive due to insufficient evidence. Conclusion:CCND1 polymorphism rs9344 may not have a role in overall cancer susceptibility in Indian population. However, this polymorphism acts as a crucial risk factor for breast, esophageal, and colorectal cancer but not for cervical cancer. Future studies with larger sample size are required to draw a reliable conclusion.
Inhibitory effect of high leucine concentration on α-amylase secretion by pancreatic acinar cells: possible key factor of proteasome
Authors: Guo Long , Liu Baolong , Zheng Chen , Bai Hanxun , Ren Hao , Yao Junhu , Xu Xiurong
Published: October 2018

The present study aimed to investigate whether leucine affects the pancreatic exocrine by controlling the antisecretory factor (AF) and cholecystokinin receptor (CCKR) expression as well as the proteasome activity in pancreatic acinar cells of dairy calves. The pancreatic acinar cells were isolated from newborn Holstein bull calves and cultured using the Dulbecco’s modified Eagle’s medium/nutrient mixture F12 Ham’s liquid (DMEM/F12). There were six treatments of leucine dosage including 0 (control), 0.23, 0.45, 1.35, 4.05, and 12.15 mM, respectively. After culture for 3 h, the samples were collected for subsequent analysis. As the leucine concentration increased from 0 to 1.35 mM, the α-amylase activity in media decreased significantly (P<0.05), while further increase in leucine concentration did not show any decrease in α-amylase activity. Addition of leucine inhibited (P<0.05) the expression of AF and CCKR, and decreased the activity of proteasome (P<0.05) by 76%, 63%, 24%, 7%, and 9%, respectively. Correlation analysis results showed α-amylase secretion was negatively correlated with leucine concentration (P<0.01), and positively correlated with proteasome activity (P<0.01) and the expression of CCK1R (P<0.01) and AF (P<0.05). The biggest regression coefficient was showed between α-amylase activity and proteasome (0.7699, P<0.001). After inhibition of proteasome by MG-132, low dosage leucine decreased (P<0.05) the activity of proteasome and α-amylase, as well as the expression of CCK1R. In conclusion, we demonstrated that the high-concentration leucine induced decrease in α-amylase release was mainly by decreasing proteasome activity.
Operating regimes of a controlled dual‐wavelength semiconductor laser system through four‐wave mixing‐ mediated by injection‐locking
Authors: Roberts Daniel R.G. , Pierce Iestyn
Published: October 2018

A method of generating a non‐zero frequency spacing between two laser diodes, using four‐wave mixing, mediated by injection‐locking in order to potentially realise THz radiation is presented. Four distinct regimes of operation are observed, including a periodic response, where the oscillations are simply related to the relaxation oscillations of the system; a periodic response with multiple frequency components, where there is a harmonic relationship between the fundamental frequency and the other frequency components; a chaotic response, where the apparent frequency components are not harmonically related; and finally the locking condition between the lasers, where a continuous wave operation is apparent. A clear linear relationship between the frequency offset and the detuning frequency while operating under the locking condition is observed, and there is a clear transition in behaviour on either side of the locking region, where the system shows a nonlinear behaviour. For higher injection rates, locking is only observed at either end of the locking region, and from this arises a so‐called generalised locking region.
Study on circuit breaker TRV issues of UHV high series compensation lines
Authors: Zheng Bin , Xiang Zutao , Ban Liangeng , Jiang Hongli , Wang Xiaotong , Teng Wentao
Published: October 2018

Under the influence of series compensation (SC) capacitance and rated voltage rise, when ultra high voltage (UHV) high SC line occurs inner fault, the short‐circuit current through the SC line is greater and the residual voltage across the SC is higher, which cause the electromagnetic transient process excited by high amplitude current and voltage to be more serious in the event of fault occurrence and removal. The security of circuit breaker (CB) equipment is threatened, which make it need further research on the characteristics and put forward some effective solutions. In this study, the characteristics of macroscopic statistical distribution of peak value via short‐circuit current of transient recovery voltage (TRV) across CB fracture during switching after short‐circuit current zero crossing for UHV high SC line are put forward, and also of the microscopic characterization parameter of waveform rise rate and peak value time. It shows that the TRV switching capability of existing UHV CBs can not cover all the fault scenarios of high SC line. Solutions including comprehensive comparison of TRV optimal suppression measures and increase of the UHV CB switching expected TRV test requirements are put forward, which provide feasible technical scheme for CBs reliable switching of UHV high SC line.
Prediction model of insulator contamination degree based on adaptive mutation particle swarm optimisation and general regression neural network
Authors: Wang Rumeng , Zhang Ming , Jiang Yunpeng , Yang Yong
Published: October 2018

The contaminants accumulated on the surface of transmission line insulator mainly come from the suspended particles in the air. Therefore, it is necessary to consider meteorological factors and environmental factors in the prediction of insulator contamination degree. In view of the advantages of generalised regression neural network (GRNN) in the aspects of fault tolerance and robustness, this study uses it to predict equivalent salt deposit density (ESDD). Furthermore, the adaptive mutation particle swarm optimisation and GRNN prediction model is proposed in this study. According to adaptive algorithm and mutation algorithm, the inertia weight and acceleration factor of particles are dynamically adjusted to achieve the purpose of searching global optimal smoothing factor. The optimisation method can effectively avoid the premature convergence of particle swarm optimisation (PSO) and solve the drawback that PSO is easy to fall into the local optimal value. The results show that the prediction model proposed in this study can effectively predict the insulators ESDD, and the prediction error is less than the GRNN and PSO–GRNN models. The research can provide guidance for the development of a more scientific and rational maintenance plan to achieve effective control of the contaminants of the line.
Simulation on the development progress of positive glow corona discharge from ground wire of AC/DC transmission lines under thunderstorm condition
Authors: Fan Shuochao , Lu Yi , Gao Yanfeng , Li Yu , Zhang Xu
Published: October 2018

In thunderstorm weather, lightning induction appears on the surface of ground objects, and then the positive glow corona is initiated, which influences the selection of lighting targets by lighting leader. So, it has great research value for lightning protection of AC/DC transmission lines. Here, a two‐dimensional model of positive glow corona is established in COMSOL Multiphysics. From the simulation results of its development progress, corona current, ion distribution, and migration are revealed. The positive ions are in a round symmetric distribution at the initial stage of migration, but when the ions move farther away, ions become an elongated oval distribution. Also, most of the ions move to the thundercloud in the end. The positive ions accumulate above the transmission line and form a positive background, which has confinement and attenuation to electronic beam. Therefore, the probability of the electron avalanche converted into flowing is reduced. Meanwhile, the positive background promotes the compound of ions and electrons. As a result, the initiation of upward leader is suppressed and so the selection of lighting targets by lighting leader is influenced.
Distributed equalisation strategy for multi‐battery energy storage systems
Authors: Fan Feilong , Tai Nengling , Huang Wentao , Zheng Xiaodong , Fan Chunju
Published: October 2018

Multi‐battery energy storage systems (MBESSs) are widely adopted to overcome the uncertainty problem of renewable energy sources. However, state‐of‐charge (SOC) imbalance issue of MBESSs brings great challenges to the optimal dispatching strategy and the lifetime management strategy for the MBESS. This study proposes a distributed equalisation strategy for the MBESSs to solve the stated problem. An equitable operation optimisation model is proposed in the distributed equalisation strategy. The equitable optimisation model can be simplified as a convex quadratic optimisation problem. An equitable approximation method is utilised to solve the convex quadratic optimisation problem according to the Karush–Kuhn–Tucker optimality conditions. Based on the equitable approximation method, the SOC balance process is distributed into different iteration steps. The iteration of the SOC balance process is implemented by the communication system connecting the distributed management systems (DMSs). The distributed SOC balance step is implemented by the DMSs of the batteries. The proposed strategy is validated by a hardware‐in‐the‐loop simulation system based on the RT‐LAB. Test results show that the proposed strategy ensure the SOC balance and improve the robustness of the MBESS.
Impact of variable DC reactors in voltage‐source converter based multi‐terminal high‐voltage DC transmission systems
Authors: Li Hui
Published: October 2018

A novel variable DC reactor is proposed to cooperate with DC circuit breaker (DCCB) for breaking DC fault currents, which can satisfy the requirement of fast protection in high‐voltage DC grids. Meanwhile, the variable reactor possesses other advantages such as smaller size, less loss and a small impact on the design of DCCBs. According to an electromagnetic characteristic of the reactor, a mathematical model of variable DC reactor is built on the base of experiment analysis. A three‐terminal VSC‐MTDC system with variable DC reactors is established in power systems computer‐aided design/electromagnetic transient design and control. Simulation results are obtained as follows. First, the variable DC reactor possesses a low inductance during normal operations. When the received power increases, the DC reactors can reduce the adverse impact on the system stability to a great extent. Second, during a DC fault, the inductances of the variable DC reactors can increase automatically to limit the rising rate of short‐circuit current and to extend the arriving time of the peak current. The application of variable DC reactors can provide the condition for DCCBs breaking fault currents successfully.
Research on mechanical fault diagnosis method of power transformer winding
Authors: Bin Zhang , Dan Zhao , Feiming Wang , Kejian Shi , Zhenyang Zhao
Published: October 2018

Today, the accuracy of the fault mechanical diagnosis of transformer winding is low and the fault types cannot be judged, this study proposes a machine condition diagnosis method of transformer winding based on the combination of short‐circuit reactance and mechanical vibration. During the process of diagnosis, first of all, from a power transformer's one and two side current and voltage, it can calculate the internal short‐circuit reactance of the winding to judge the winding state. Then, it uses the wavelet transform to analyse the vibration signals of the transformer windings under different conditions and it uses the signal spectrum entropy as the input feature vector. Finally, using multi class support vector machine to train and test the feature vector, it realises the classification diagnosis of transformer winding in different states. By setting the actual different transformer winding faults of type S11‐M‐500/35, it gathers the corresponding parameter data and it tests the diagnosis method for the fault diagnosis of transformer winding verification. The diagnosis results are consistent with the actual fault, which verifies the validity and accuracy of the proposed method that is applied to the transformer winding fault diagnosis.
Transient overvoltage on overhead metal return lines of ±500 kV MMC‐HVDC grid
Authors: He Huiwen , Li Xiaolan , Lou Ying , Wang Lei , Zhou Peihong
Published: October 2018

The ±500 kV half‐bridge modular multilevel converter‐high‐voltage DC (MMC‐HVDC) grid project with overhead transmission line is under construction in China at present. For MMC‐HVDC grid, only one electrical grounding point is allowed and thus, the metal return lines on the same towers with positive and negative polar lines are necessary. However, current studies mainly focused on the control methods of MMC‐HVDC substation and few studies have been done on the transient overvoltage of overhead transmission line for the MMC‐HVDC project. This study analysed the main transient overvoltage types of metal return lines of ±500 kV half‐bridge MMC‐HVDC grid which transmit electric power by overhead lines and clear the grounding fault by DC breakers. Based on a ±500 kV MMC‐HVDC grid project, the simulation models were built using PSCAD and the possible transient overvoltage types were studied. The results showed that the most serious overvoltage was caused by the DC breaker clearing the grounding fault. Then the insulation coordination design for metal return lines was carried out. The recommended arcing horn clearances at different altitude were given. The research results provided support for the insulation design of the transmission line.
Matrix converter based virtual synchronous generation technology
Authors: Li Chuyun , Guo Yougui , Deng Wenlang , Wang Xiao
Published: October 2018

Energy is an important driving force for social development. The shortage of natural resources urgently promotes the research of energy and the development of related technologies. Meanwhile, the distributed generation is one of the most important approaches. Virtual synchronous generator (VSG) technology, as a kind of control strategy that can participate actively in grid power regulation, has drawn much attention. Traditional VSG technology uses the two‐level inverter as the main circuit. Based on the theory of VSG and the matrix converter (MC) as the main circuit of the VSG, the control system can imitate synchronous generator's characteristics such as inertial characteristics, frequency response characteristics and frequency modulation. The method provides a feasible solution for the power conversion of the distributed generation, which is the AC output, omitting the procedure of AC–DC–AC. Through the simulation, it is verified that the VSG technology can be applied to the MC, which provides a new idea for the exchange transformation in distributed generation.
Research on the simulation modelling of high‐voltage switchgear ring‐shaped spring contact force
Authors: Zhijun Wang , Yujing Guo , Yongqi Yao , Yapei Liu , Gang Wang , Bo Zhang , Hao Zhang , Xiangyu Hao
Published: October 2018

In order to explore the simulation method of the contact force for the ring‐shaped spring and provide the support for the design of high‐voltage switchgear‐rated current and mechanical operating power, the parametric equation was derived, based on NX software the three‐dimensional model was built, considering the influence of contact, friction, and large deformation, the non‐linear dynamic finite element simulation model for the process of assembling and operating was established, the stress, resistance force, and friction force at any moment were obtained by simulation, and the variation of resistance and friction force during contact insertion was analysed. The results show that during the mechanical operating process, the resistance force rapidly increased to the extreme value and then gradually decreased to a stable value of 238N, and the friction force quickly increased and then slowly rose to the steady value of 238N, which is consistent with the experience and proved the rationality of the simulation model. Finally, according to the Coulomb friction law, the contact force of the spring contact was calculated as 1190N.
Quasi proportional‐resonant control for the grid current of hybrid distribution transformer
Authors: Liang Yang , Liang Deliang , Liu Yibin , Zhang Mingkang , Jia Peixin , Sun Guanhua
Published: October 2018

Hybrid distribution transformer (HDT) has powerful control ability, which is significant for the intelligentisation of the distribution network. A kind of HDT is presented here, the grid current control system of which is emphatic researched. Based on the mathematical model of ideal HDTs, a grid current control system is designed with quasi proportional‐resonant controller (QPR). Using the characteristics that infinite gain and large bandwidth at the resonant frequency of QPR controller, the grid current system achieve the effects of unit power factor and sinusoidal symmetrical waveform. Tracking control with no static error of grid current was achieved in MATLAB. Compared with the traditional PI control, QPR controller can modulate AC signals in the static coordinate system, rather than rotary coordinate system. So the QPR controller has advantages of lower steady‐state error, stronger anti‐interference ability, and simpler calculation. Simulation results show that it has good dynamic and steady performance.
Control method for EV charging and discharging in V2G/V2H scenario based on the synchronvter technology and H∞ repetitive control
Authors: Liu Dongqi , Zeng Xiangjun , Liu Guorong
Published: October 2018

Electric vehicles (EVs) will play a vital role in the future's transportation systems since this technology is promising for environment, energy security, and improved fuel economy. EVs have huge potential of serving as the energy storage for the power grid as well as inhabitants in vehicle‐to‐grid (V2G) or vehicle‐to‐house (V2H) scenario. In this study, a control method is proposed for EV charging and discharging by using the synchronverter technology and H ∞ repetitive controller, where synchronverter technology is used to generate the reference voltage to decide the power angle and amplitude of the AC side voltage of the charging/discharging port, so that the power flow between EV and the grid is controlled. In order to ensure the power quality of EVs provided for the grid and the load while EVs are with local loads, a H ∞ repetitive controller is designed to control the voltage between EVs and the grid to follow the reference voltage. Simulation results have shown that the proposed controller is not only able to realise bi‐directional real power and reactive power control, but also keep the output voltage of EVs in V2G or V2H scenario stable and clear while they are with different kinds of local loads.
Improved niche genetic algorithm based parameter identification of excitation system considering parameter identifiability
Authors: Liu Xingjie , Yan Liang , Liu Yadong , Zhao Liquan , Jie Jinxing
Published: October 2018

In order to obtain the parameters of excitation system accurately, and improve the accuracy and efficiency of parameter identification much further, an improved niche genetic algorithm was adopted, which can overcome local convergence of genetic algorithm by the fitness sharing mechanism that could increase population diversity. Moreover, the proposed algorithm could avoid the disadvantage of usual niche genetic algorithm that is difficult in determining the niches. By using the method of fuzzy clustering, niche groups can be created dynamically. In addition, regarding the problem that the partial parameters of excitation system cannot identify stably because of the relevance among these parameters, this study analysed the identifiability of excitation system model primarily, separated associated parameters into several parameter sets then. This type of relevance would be removed by assigning typical values to representative parameters, which belong to different sets. Identifiability analysis can not only avoid identifying parameters blindly, but also increase the credibility of the results. The test study shows that the proposed method can acquire accurate and reliable parameter values.
Active power decoupling and controlling for single‐phase FACTS device
Authors: Zhang Junmin , Liu Kaipei , Liu Yan , He Shunfan , Tian Wei
Published: October 2018

Single‐phase FACTS device has a bulky and short‐life electrolytic capacitor to absorb the ripple pulsating at twice of the line frequency in DC side, resulting in lower power density. This paper introduced a structure of three‐phase bridge which added an additional leg connected to an AC capacitor based on single‐phase H‐bridge. The 2‐ripple energy of the electrolytic capacitor in single‐phase H‐bridge could be transformed to the film capacitor of the AC side in three‐phase H bridge. The size of single‐phase FACTS is reduced by ten times compared to the single‐phase H‐bridge. A simple control strategy had been studied, through two kinds of controllers: the digital quais‐PR controller had been used to control gird current and AC capacitor voltage and current; the two cosine controller had been used to eliminate the rest of two‐ripple harmonic in the DC side, there was no controller to maintain DC voltage. The experiments verified the feasibility of the control strategy.
Iterative design method of LCL filter for grid‐connected converter to achieve optimal filter parameter combination
Authors: Tong Li , Chen Chao , Zhang Jianping
Published: October 2018

This study proposes an iterative design method of L‐type Inductor, Capacitor, and L‐type Inductor (LCL) filter for grid‐connected converter to achieve optimal filter parameter combination. LCL filter is commonly used for to reduce high frequency harmonic pollutions being injected into distributed power network. Accordingly, the performance of harmonics attenuation is taken as the most decisive constraint for filter parameter design. Usually, traditional methods apply the full‐modulated operating condition to acquire amplitudes of present voltage harmonics, leading to over‐designed capability of harmonics attenuation, which means increased inductance, degraded dynamic response, and enlarged weight and space. To deal with these challenges, the harmonic distortion factor is first proposed to evaluate the influence of different order voltage harmonic on grid current distortion. Also then, with four deduced constraint functions, an iterative design procedure is proposed to obtain satisfactory region of all filter parameters. As a result, the capability of harmonics attenuation can be precisely designed, and the optimal parameter combination brings about significant reduction of filter inductance. For instance, compared with the traditional method, the total inductance can be reduced by 23.3% in a 10 kW system. Finally, the experimental results are presented to demonstrate the effectiveness of proposed method.
High current field test of impulse transient characteristics of substation grounding grid
Authors: Tong Xuefang , Dong Xiaohui , Tan Bo
Published: October 2018

It is significant to research the impulse characteristics of substation grounding grid for its optimal design and safe and stable operation. In order to obtain the impulse transient characteristics of substation grounding grid under lightning impulse current more accurately, the impulse current field test was done on a real substation grid. By monitoring the impulse grounding impedance, impulse coefficient, longitudinal current, and node potential under different test conditions, impulse characteristics curves and the effect of some influence factors are gotten, then the main zones of current dispersion and voltage drop are proposed, as well as the effective areas under different conditions are proposed combined with simulation analysis. The results show that: the impulse grounding impedance and impulse coefficient are smaller when the current is injected from the central of the grid. The main current dispersion region of the large‐scale grounding grid is about 40 m around the injection point. The potential drops about 30% within 20 m around the injection point, and the change of the potential is small in the far distance. The effective area of substation grounding grid is affected by soil resistivity, and its side length is usually only tens of meters.
Research on DC grid control and analysis method based on pilot voltage
Authors: Wang He , Zhu Tianquan , Li Guoqing , Bian Jing , Jin Rukong
Published: October 2018

DC voltage control is one of the key technologies of DC power grid operating control. Here, the local voltage measurement is replaced by the pilot voltage in traditional droop control, and the droop control based on the pilot voltage is applied to the DC power grid. When the power disturbance appears in the DC power grid, the coordination of multiple converter stations can be better realised and the voltage fluctuation of the DC power grid can be reduced. In addition, this paper also applies the concept of pilot voltage to the analysis and control of interconnected DC power grid, and analyses important significance of pilot voltage to DC power grid. The transmission of the power in DC interconnected system can be guided by the change of the pilot voltage. The simulation results verify the effectiveness of the proposed method.
Analysis of high‐frequency interference characteristics of UHVDC converters
Authors: Ying Chaonan , Xu Zheng , Luo Chenxi
Published: October 2018

The converter is the main component of the converter station and the main noise source of the PLC interference. The accurate modelling of the high‐frequency characteristics of the converter is the foundation for the design of the ± 1100 kV UHVDC PLC filter. Based on deep analysis of the high‐frequency characteristics of the converter valve, this paper first proposes three high‐frequency models of the converter valve. Compared with a real converter valve used in similar HVDC project, model two is chosen to analyse the high‐frequency characteristics. Second, the model of Zhundong–Wannan UHVDC transmission project is established in the PSCAD simulation platform to determine the actual high‐frequency characteristics of the converter valve. The voltage before the smoothing reactor is calculated, and the high‐frequency noise level is obtained by Fourier transform. Considering the practical application of the high‐frequency model of the converter valve, this paper finally proposes a formula to express the measured noise level. The noise source expressed by the formula is more practical for research on high‐frequency characteristics of the converter station.
Switching frequency regulation in sliding mode control for synchronous buck converter
Authors: Liu Songbin , Feng Zhiyuan , Cai Yu
Published: October 2018

This study aims to control the switching frequency of synchronous buck (SR‐buck) converters using the second‐order sliding mode controller by prescribed control law. The relation between position of the switching line and the switching frequency is discussed at stable state. On‐resistance of MOSFET and ESR of inductor and capacitor are taken into account. A hysteresis method is proposed to change the position of switching line to control the switching frequency, and the equation of calculating hysteresis width is deduced. The differentiator with the discrete super‐twisting is designed. Numerical simulation results under rated working condition, load disturbance, voltage perturbation, and switching frequency variation have been presented. Switching frequency variation is discussed and can be controlled accurately when the working condition is fixed. It validates the effectiveness and feasibility of the method proposed in this study.