bluuebunny/crossref_metadata_2025 huggingface dataset:
Substrate stiffness heterogeneities disrupt endothelial barrier integrity in a micropillar model of heterogeneous vascular stiffening
Authors: VanderBurgh Jacob A. , Hotchkiss Halie , Potharazu Archit , Taufalele Paul V. , Reinhart-King Cynthia A.
Published: October 2018

We are first to show that endothelial monolayers simultaneously contacting stiff and compliant matrix adopt the phenotype associated with the stiffer matrix.
Extraction of electrokinetically separated analytes with on-demand encapsulation
Authors: van Kooten Xander F. , Bercovici Moran , Kaigala Govind V.
Published: October 2018

On-demand two-phase encapsulation of electrokinetically separated analytes decouples electrokinetic separations from downstream analytical processes.
A biodegradable Fe-fertilizer with high mechanical property and sustainable release for potential agriculture and horticulture applications
Authors: Li Tao , Lü Shaoyu , Ji Yanzheng , Qi Taomei , Liu Mingzhu
Published: October 2018

A low-cost and biodegradable Fe-fertilizer bead with sustained release behaviors and excellent mechanical strength for potential agriculture applications.
Correction: Influence of annealing temperature on the spectroscopic properties of hydroxyapatite analogues doped with Eu3+
Authors: Zawisza Katarzyna , Strzep Adam , Wiglusz Rafal J.
Published: October 2018

Correction for ‘Influence of annealing temperature on the spectroscopic properties of hydroxyapatite analogues doped with Eu3+’ by Katarzyna Zawisza et al., New J. Chem., 2017, 41, 9990–9999.
Supercritical CO2-induced atomistic lubrication for water flow in a rough hydrophilic nanochannel
Authors: Ho Tuan A. , Wang Yifeng , Ilgen Anastasia , Criscenti Louise J. , Tenney Craig M.
Published: October 2018

Flow enhancement in a rough hydrophilic nanochannel due to an atomistic lubricant.
Responsive peptide-based supramolecular hydrogels constructed by self-immolative chemistry
Authors: Zheng Debin , Gao Zhengfeng , Xu Tengyan , Liang Chunhui , Shi Yang , Wang Ling , Yang Zhimou
Published: October 2018

Peptide-based supramolecular hydrogels that are stimuli-responsive under aqueous conditions have many potential biological applications, including drug delivery and sensing.
Freezing-assisted synthesis of covalent C–C linked bivalent and bispecific nanobodies
Authors: Zang Berlin , Ren Jun , Li Da , Huang Chundong , Ma Hao , Peng Qiang , Ji Fangling , Han Lulu , Jia Lingyun
Published: October 2018

C–N linked bivalent nanobody (upper) and C–C linked nanobody (bottom) presented as cartoon. (The elephant represents the nanobody; the banana represents the antigen).
Surfactant-assisted galvanic synthesis and growth characteristics of copper nanowires
Authors: Chang Yu-Hsu , Lin Tung-Jung , Wu Yu-Chuan , Fan Sheng-Wei , Lee Yuan-Han , Lai Yi-Ru
Published: October 2018

One-dimensional copper nanowires (CuNWs) are synthesized on a large-scale using a cetyltrimethylammonium chloride-assisted galvanic replacement reaction on aluminum substrates.
Interlayer-expanded and defect-rich metal dichalcogenide (MX2) nanosheets for active and stable hydrogen evolution
Authors: Xu Jun , Huang Yanyan , Cheng Xialan , Liu Tong , Lu Yingchun , Chen Xing , You Yu , Zhang Junjun
Published: October 2018

A series of interlayer-expanded and defect-rich MX2 nanosheets with abundant active edge sites are synthesized and demonstrated as efficient electrocatalysts for superior hydrogen evolution.
Double B←N bridged bipyridine-containing polymer acceptors with enhanced electron mobility for all-polymer solar cells
Authors: Long Xiaojing , Yao Jiuyong , Cheng Fangfang , Dou Chuandong , Xia Yanzhi
Published: October 2018

Two novel polymer electron acceptors based on double B←N bridged bipyridine with enhanced electron mobilities were synthesized for efficient all-polymer solar cells.
Sonodynamic therapy induces oxidative stress, DNA damage and apoptosis in glioma cells
Authors: Sun Yue , Wang Haiping , Zhang Kun , Liu Jingfei , Wang Pan , Wang Xiaobing , Liu Quanhong
Published: October 2018

Malignant glioma remains one of the most challenging diseases to treat because of the invasive growth of glioma cells and the existence of the blood–brain barrier (BBB), which blocks drug delivery to the brain.
The prognostic value of C-reactive protein/albumin ratio in nasopharyngeal carcinoma: a meta-analysis
Authors: Gao Nan , Yang Ruo-Nan , Meng Zhen , Wang Wan-Hai
Published: October 2018

The C-reactive protein/albumin ratio (CRP/Alb ratio) has been reported to have promising prognostic value in several cancers. The current meta-analysis was conducted to better define the prognostic value of CRP/Alb ratio in patients with nasopharyngeal carcinoma (NPC). The Web of Science, Embase, Cochrane Library databases, and PubMed were searched up to 25 February 2018 for the information on CRP/Alb ratio and outcomes of NPC. Pooled hazard ratios (HRs) and corresponding 95% confidence intervals (95% CIs) were used to evaluate the association between CRP/Alb ratio and survival outcomes in NPC. A total of five studies with 5533 patients with NPC were included. Pooled results showed that high CRP/Alb ratio was associated with poor overall survival (OS) (HR = 1.51, 95% CI: 1.30–1.75, P<0.001) and poor distant metastasis-free survival (DMFS) (HR = 1.23, 95% CI: 1.07–1.43, P=0.005). Subgroup analyses showed that patients with higher CRP/Alb ratio have worse OS in NPC. In conclusion, elevated CRP/Alb ratio was associated with worse prognosis in patients with NPC.
Diagnostic potential of circulating LncRNAs in human cardiovascular disease: a meta-analysis
Authors: Luo Fei , Wang Tao , Zeng Lini , Zhu Shanshan , Cao Wenjun , Wu Wei , Wu Hongfu , Zou Tangbin
Published: October 2018

Cardiovascular disease (CVD) is a major killer of the human population around the world. Identifying effective diagnostic biomarkers for CVDs is particularly important in order to guide optimizing treatment. Accumulating evidence on aberrantly regulated circulating long non-coding RNAs (LncRNAs) promise to serve as a diagnostic or prognostic biomarker for various types of CVDs. We summarized studies to identify the potential diagnostic values of LncRNAs in CVD patients. We included articles reporting on the association between LncRNAs and diagnosis in CVDs. We calculated sensitivities, specificities, and area under the curves of LncRNAs. The pooled overall sensitivity and specificity for LncRNAs expression profile in differentiating CVD patients from controls (non-CVDs or healthy subjects) were 0.74 (95%CI 0.68–0.80) and 0.81 (95%CI 0.76–0.85), respectively; the overall positive likelihood ratio, 3.9 (95%CI 3.1–4.9); the negative likelihood ratio, 0.32 (95%CI 0.25–0.40); corresponding to an area under curve of 0.85 (95%CI 0.82–0.88) and overall diagnostic odds ratio 12 (95%CI 9–18). Subgroup analysis showed that the detection of LncRNAs expression in plasma substantially improved the diagnostic accuracy. Likewise, meta-regression analysis indicated that the detection method and sample size were the main source of heterogeneity. All these results suggested a relatively good reference value of LncRNAs as auxiliary biomarkers for CVDs, and should be considered in cases where the diagnosis is uncertain. Population-based prospective cohort studies are warranted to confirm our findings.
Optimisation of convergence‐aware coded PDMA for 5G wireless systems
Authors: Xu Jin , Han Xueqin , Ding Hanqing , Li Zhigang , Yu Zeqi , Dai Xiaoming
Published: October 2018

Orthogonal frequency division multiplexing‐based pattern division multiple access (PDMA) is considered as a promising multiple access scheme for future wireless communication systems due to its high spectral efficiency and powerful ability to support massive users. In this study, it is shown that two pattern matrices with unequal diversity gain in the PDMA system have better convergence performance compared with the signature matrices in a traditional low‐density signature multiple access system by simulations and extrinsic information transfer (EXIT) chart analysis. For a low‐density parity check (LDPC)‐coded PDMA system, the EXIT characteristics between the front‐end multiple‐user detector (MUD) and the LDPC decoder may be mismatch, which usually leads to degraded performance when an iterative detection and decoding algorithm is used. To overcome this problem, a two‐stage iterative optimisation algorithm, which is easy to implement is proposed to find an optimal (near optimal) degree distribution pair for the LDPC code. Both EXIT chart analysis and simulation results demonstrate that the proposed algorithm exhibits further performance gain compared with regular (3,6) LDPC‐coded systems under both an additive white Gaussian noise channel and a Rayleigh fading channel.
Secrecy performance analysis over cascaded fading channels
Authors: Ata Serdar Ö.
Published: October 2018

In this study, the authors investigate the secrecy performance at the physical layer of wireless communication systems where the channels are modelled as cascaded fading channels, in which the fading effects are worse than those in the cellular communication channels like Rayleigh and Nakagami‐m. Analytic results are derived for the cascaded Nakagami‐m fading channel model comprising the cascaded Rayleigh, 2*Nakagami‐m, the generalised‐K, and the conventional cellular channel models as well. By evaluating the information‐theoretic physical layer security performance, they obtain the closed‐form expressions of the average secrecy capacity and probability of the positive secrecy capacity in case of that channel‐state‐information of the eavesdropper is known by the source. Then they obtain the exact closed‐form secrecy outage probability (SOP) when the eavesdropper is passive. Analytic results are computed in terms of the bivariate and univariate Meijer's G functions and later on are successfully validated through Monte Carlo simulations. The simulation results show that the secrecy performance worsens with the increasing cascading degree of the fading channels. For example, in 2*Nakagami‐m fading channels where the cascading degree is 2, extra 4 dB signal‐to‐noise ratio is required to achieve the same SOP value in comparison with the classical Nakagami‐m fading channels.
Estimation of the parameters of stochastic differential equations for sea clutter
Authors: Roussel Clement Julien , Coatanhay Arnaud , Baussard Alexandre
Published: October 2018

When the sea surface is illuminated by a radar sufficiently far away and in the absence of a coherent target, the scattered electromagnetic signal, called ‘sea clutter’ is unpredictable and can be represented by a stochastic process. A model based on stochastic differential equations and consistent with previous statistical models (K distribution) has been proposed. It depends on three parameters: , , and . To estimate them, maximum likelihood estimators for and , and an estimator based on the hypothesis of ergodicity for are proposed in this study. The authors compare three expressions for the transition probabilities: the exact one, Euler's approximation, and Nowman's approximation. By regenerating the trajectories from the same Brownian increments, they can quantify the typical error made on the sea clutter from the typical error made on the estimated parameters. Though the exact transition probabilities minimise the error on the sea clutter, they show that an approximation such as Euler's is sufficient.
Virtual signal‐integrity verification tool for copper twisted‐pairs using TDR
Authors: Chuah Teong Chee , Ng Yin Hoe , Hashim Nabihah , Zainal Abidin Ahmadun Nijar , Asrokin Azhari
Published: October 2018

Time‐domain reflectometry (TDR) is an important technique for verifying the impedance and quality of signal paths in components, interconnects, and transmission lines. However, the success of channel condition assessment through on‐site interpretation of TDR echoes hinges on the skill and experience of the operator. This study presents a TDR simulator to assist loop diagnostics on copper twisted pairs widely used in current digital subscriber line (DSL) access networks. The simulator is developed based on established frequency‐dependent cable models to synthesise realistic TDR echoes arising from various cable discontinuities. Modelling of arbitrary loop configurations and faults is accomplished by cascading multiple sub‐lines with different characteristics through ABCD parameters modelling. The usability of the simulator is enhanced using a graphical user interface and its accuracy has been verified experimentally using TDR echoes obtained from commercial TDR testers. Since lengthy twisted pairs are deployed in real DSL access networks, the TDR simulator can be used to perform on‐site simulation and verification during DSL network maintenance and troubleshooting, as well as to gain mastery of TDR handling while circumventing the need for bulky and costly cabling test beds. The simulator can also be useful to supplement the teaching of electromagnetics and high‐frequency measurement.
Modelling and simulation of AC–DC hybrid distribution network based on flexible DC interconnection
Authors: Chen Liang , Jia Mengmeng , Huang Qiang , Yuan Xiaodong
Published: October 2018

AC and DC hybrid distribution network detailed modelling and multi‐operation conditions of the simulation analysis will effectively support the distribution network project reliable and stable operation. However, at present, large‐scale system‐level simulation of AC–DC hybrid distribution network based on flexible DC is the lack of timeliness and practicability. Based on the real‐time digital simulation platform RT‐LAB, ACDC distribution network model is established, which includes ±20 kV flexible DC interconnection system, distributed photovoltaic, wind power, energy storage system, electric vehicle and the corresponding converter control detailed modelling. In view of the limitation of the balance of energy storage system, the flexible DC interconnection is applied to active distribution network, which can provide power supply when the power gap occurs. The conditions of consumptive mode by the energy storage system, power supply through flexible DC interconnection from external power grid were simulated and analysed. The model verifies the validity of the system application in distribution network. This study provides preliminary design reference for active distribution network construction.
Study on frequency domain dielectric spectroscopy of epoxy resin impregnated paper bushings under damp conditions
Authors: Xu Zuoming , Yi Fuquan , Hu Guanpeng , Wang Xin , Yin Pengbo , Hu Wei , Peng Zongren
Published: October 2018

Epoxy resin impregnated paper (RIP) bushings are widely used as transformer bushings and wall bushings, but this type of bushing is easy to be dampened. In order to study the effect of moisture on the bushings' insulation performance, a test device was established to simulate the moisture absorption process in the air or N2 gas. Based on the frequency‐domain dielectric spectroscopy (FDS) method, FDS curves that indicate the dielectric loss factor (tan δ) and capacitance (C) under different frequencies were tested and analysed. The results demonstrated that the FDS curve moves to the high frequency direction with the increase of the moisture content, and there exist minus tan δ and a negative peak in low‐frequency band. Since the moisture content is much lower than in the air, tan δ and C under power frequency of the bushing almost unchanged in the N2 gas. However, the tan δ under 0.1 Hz increases sharply with the increase of trace moisture, and the higher moisture content, the greater increase rate. A damp diagnosis method for RIP bushings is proposed based on the FDS curves' frequency translation characteristics and tan δ variation law. Also the results can give references for RIP bushings' insulation diagnosis.
Analysis of wireless power transfer based on metamaterial using equivalent circuit
Authors: Rong Cancan , Lu Conghui , Hu Zhaoyang , Huang Xiutao , Tao Xiong , Wang Shengming , Wei Bin , Wang Songcen , Liu Minghai
Published: October 2018

The metamaterial (MA) has been proved to enhance the efficiency of the wireless power transfer (WPT) system considerably in many studies. This study presents an equivalent circuit model using a qualitative and even quantitative simple explanation for the behaviour of MA in WPT. For this purpose, the electromagnetic field simulation of WPT system with MA is carried out by the high‐frequency structure simulation three‐dimensional electromagnetic simulator. Also, the authors propose the circuit structure of the WPT system based on MA and explore its characteristics by numerical calculation and advanced design system simulation. The transmission efficiency of the simulator is characterised by reflection coefficient here. Although some methods, such as interference theory, transmission line circuit model, and effective medium theory, have been put forward to explain the physics mechanism of WPT system with MA, some of reactive parameters and the basic physical interpretation have not been expounded clearly so far. Differ from the existing theoretical model, the proposed approach focuses on the effect of the system parameters of MA and transfer coils on the transfer characteristics and is beneficial to the analysis of the complicated system.
Shielding the magnetic field of wireless power transfer system using zero‐permeability metamaterial
Authors: Lu Conghui , Huang Xiutao , Rong Cancan , Hu Zhaoyang , Chen Junfeng , Tao Xiong , Wang Shengming , Wei Bin , Liu Minghai
Published: October 2018

The wireless power transfer (WPT) has attracted considerable attention due to its convenience and reliability. However, the electromagnetic leakage of WPT can be harmful to humans and environment. In order to meet safety requirements, electromagnetic leakage to the nearby transmission channel should be controlled below a certain level. Beyond ferrite and metallic shields, several researchers have proposed mu‐near‐zero metamaterial (MNZ MM). However, little work researches the application of MNZ MM in four‐coil WPT systems. Here, the authors propose an optimised MNZ MM for shielding leaked electromagnetic field. Next, the authors setup a miniaturised WPT system loaded with MNZ slab at 13.56 MHz. It can serve as a frequency selector that reflected a specified frequency of 13.56 MHz, while allowing all other frequencies to pass undisturbed. As a result, the transmission efficiency is dramatically reduced at a 30 cm distance. The magnetic field magnitude of the receiver has been decreased. Obviously, the proposed MNZ MM has good performance in magnetic field shielding for WPT systems.
Start‐up scheme for converter station of MMC‐HVDC based on single‐clamp sub‐module using in grid black start
Authors: Wang ChaoLiang , Lv WenTao , Lu Yi , Xu Feng , Qiu Peng
Published: October 2018

Single‐clamp sub‐module (SCSM) combining the cost and technological advantages has become one of the next modular multilevel converter (MMC) sub‐module topologies in response to DC fault aspect. It describes the topological structure and working conditions based on SCMMC (Single‐Clamp MMC) and proposes the three‐stage start‐up processes of SCMMC. The paper has made a detailed study on the black‐start scheme of the blackout terminal converter when SCMMC‐HVDC is used in grid black start. The active‐side SCMMC orderly rotation trigger control strategy and the passive‐side SCMMC orderly rotation bypass control strategy are proposed targeted. The paper proposes the corresponding start‐up procedures for the SCMMC‐HVDC system. At last, simulation models are established in PSCAD/EMTDC, the simulation results have validated the efficiency of the proposed black‐start scheme for the converter of the blackout terminal.
Research on the influences of location selection and permeability of wind power generation on cascading failure
Authors: Tian Yang , Xiaoming Liu , Qi Wu , Longnv Li
Published: October 2018

The main cause for cascading failure is large‐scale overload caused by localised abnormal flows. With the increase of wind power penetration, the complexity of flow distribution is strengthened. Therefore, it is necessary to study influences of site selection and permeability of wind power generation on cascading failure. An analysis method based on electric betweenness of nodes was put forward, and influences of permeability change on cascading failure on different location selection for wind power generation were researched. According to the study, it was found that when the electric betweenness was low, the overload of wind power led to declining uniformity of power flow distribution, resulting in transfer of flows to other lines. As a result, the heavy load of lines was further aggravated to promote the development of cascading failure. Simulation results of the IEEE30 system showed that with the increase of wind power penetration, the cascading failure was aggravated; and under the same permeability, the lower the electric betweenness of location selection was, the severer cascading failure would be.
Novel coordinated control strategy of urban DC distribution system for large‐scale loads reduction
Authors: Yang Chenxing , Meng Xueyang , Feng Shuhai , Xu Lizhong
Published: October 2018

In order to improve the load characteristics of urban power grid in China, the measure of shaving large‐scale controllable loads (LSCLs) has been carried out in the peak load period which causes the fluctuations of distribution system's voltage and frequency. On the other hand, more and more decentralised rooftop photovoltaic systems (RPSs) have been employed in Chinese cities, whose grid‐connected converters furtherly increase the difficulty of voltage and frequency stability control of distribution system. This study proposes a novel coordinated control strategy for the urban DC distribution system, which includes both distributed RPSs and LSCLs. The virtual synchronous motor‐based control is innovatively applied to the rectifier of the DC distribution system in the coordinated control strategy. Based on the coordinated control strategy, the equivalent model of the DC distribution system is established in the form of ‘the prime mover–the generator–the variable load’. The LSCLs reduction has effects on the voltage and frequency of the DC distribution system. The simulated results show that the effects are effectively restrained by adopting the proposed control strategy.
Coordinated control strategy of a DC grid with energy storage system
Authors: Yang Bo , Sang Bingyu , Yang Zhihan , Li Menbo , Xiang Wang , Lu Xiaojun , Yao Liangzhong , Tao Yibin
Published: October 2018

DC grid has a prospect of application in collecting and transmitting large‐scale renewable energy over long distance. However, the randomness and fluctuation of the renewable power may hamper the stable operation of DC grid. Energy storage device is able to actively absorb or supplement active power, which can be used to smooth the power fluctuation. The paper investigates a DC grid topology with energy storage and proposes a coordinated control strategy. The proposed strategy enables coordinated control of the renewable energy output power, pumped storage power and the grid consuming power. During the steady state, the control strategy enables the system DC voltage stable and power flow of the grid under zero‐error control. During the faulted time, the coordinate control strategy enables the converter fast response and maintains the system DC voltage within safety margin. The effectiveness of the coordinated control strategy is verified by simulation in PSCAD/EMTDC.
Research and experiment of a current‐limiting HVDC circuit breaker
Authors: Du Yi , Deng Junpeng , Lin Hongyang , Zheng Huan , Xiang Kangli , Shen Yu
Published: October 2018

Existing mechanical HVDC circuit breakers (CB) are capable of interrupting HVDC currents within several tens of milliseconds, but this is too slow to satisfy the requirements of a reliable HVDC grid. HVDC CB based on semiconductors can easily overcome the limitations of operating speed, but need large number of the series (parallel) connection of electronic switching devices. To overcome these shortcomings, this paper introduces a topology of hybrid CB; this paper first describes the principle of hybrid CB; then a control strategy of fault pre‐treatment is also proposed, that is, the ‘pre‐action and action (or recovery)’ of the switches, in order to improve the breaking speed of the hybrid CB and the equalising circuit of its solid‐state switch has been designed. The proposed topology and control strategy do not produce loss in the normal operation of CB, and instantaneous trigger solid‐state switch with quickly cutting short‐circuit current during short‐circuit faults; at last the simulation and experiment of the hybrid HVDC CB have also been done. The results turn out when a short circuit occurs, the hybrid HVDC CB can quickly break the short‐circuit current; the buffer circuit can be provided for the release of the stored energy circuit.
Stabilisation strategy based on feedback linearisation for DC microgrid with multi‐converter
Authors: Shao Xuanying , Hu Jian , Zhao Zhongtian
Published: October 2018

Power electronic converters have been widely used in power system and the stability issues of DC microgrid with converters will be discussed in this study. Firstly, an equivalent circuit and the corresponding state space model for DC microgrid with DC–DC converters were established. The model shows that the DC microgrid systems with DC–DC bidirectional converter in boost or buck mode is a non‐linear system, and the tightly regulated point‐of‐load converters may destabilise the system because it introduces negative incremental resistance to DC microgrid. Then the method of exact feedback linearisation, which transforms the non‐linear system into the linear system by coordinate transformation, was applied to stabilise DC microgrid system, and the stabilisation strategy of non‐linear system was determined by designing the feedback coefficient of the linearised system. Finally, the feasibility and effectiveness of the stabilisation strategy for DC microgrid with DC–DC bidirectional converter have been verified by the results of simulation with MATLAB.
Distance protection based on parameter identification considering transformer characteristics
Authors: Zheng Zhiqin , Shao Baozhu , Yu Tongwei , Liu Yakun , Song Guobing
Published: October 2018

The distance protection method with parameter identification can distinguish internal fault from external fault correctly and avoid the transient overreach effectively based on the accurate secondary signal data. However, due to the limitation of the frequency band of the electromagnetic transformer, the secondary signal distortion is caused when the transient signal is transmitted, which limits the application of the parameter identification principle. Here, a matching method of line model and transformer type for relay protection is proposed. Analysed the appropriate frequency band of line model and transformer linear transfer frequency band and the electrical signal beyond their intersection should be filtered out. The simulation results show that this method improves the accuracy of the operation. This method not only makes sense to the practical application of distance protection based on the principle of parameter identification, but also has some reference value to other engineering applications.
Influence of distributed photovoltaic power generation on distribution network and the design of optimal access scheme
Authors: Zhang Hao , Tong Xiangqian , Yin Jun
Published: October 2018

Distributed photovoltaic (PV) access to distribution network will affect the line loss and voltage of the system, and affect the reliability and economic operation of the distribution system. Therefore, in this study, firstly, node analysis models of distribution network system with four different typical load distribution is established. Secondly, the changes of voltage and network loss caused by distributed PV access to distribution network systems with four typical load distribution are analysed, and the formula of optimal access position and optimal access capacity of distributed PV system under different load distribution system is derived. Thirdly, on the basis of the work data of a distribution line with 43 distributed PV access in Tongchuan city, Shaanxi Province, China, the influence of distributed PV power generation on line loss and voltage of distribution network under different weather conditions are analysed. Finally, an optimal PV access scheme for distribution network based on ant colony algorithm is proposed to ensure the reliable and economical operation of distribution network after distributed PV access. The simulation model of distribution system with distributed PV access is established under Matlab, and the simulation results show the correctness and effectiveness of the proposed formula and the optimisation scheme.
Solve the passive interference of UHF transmission lines based on LE‐PO method
Authors: Tang Bo , Li Yaowei , Huang Hansheng
Published: October 2018

On the research about the ultra‐high frequency (UHF) re‐radiation interference (RRI) from the power lines, traditional high‐frequency algorithms need excessive computing resources or have a bad calculation precision. Based on the surface model of RRI, the calculation idea using large element‐physical optics (LE‐PO) is proposed to calculate the level of RRI. According to the assumption of LE‐PO, the electric field integral equation is simplified. When the excitation source is plane wave, Linearly Phased‐Rao Wilton Glisson (LP‐RWG) basis functions are used to disperse the surface‐induced current and the expression of scattering field from the tower of power lines was deduced. Related analysis example is used to analyse the calculation precision and the computing resource of LE‐PO. As a result, the computing resources of LE‐PO are much less than PO, while the calculation precision of LE‐PO is the same as PO.
Fault response comparison of LCC–MMC hybrid topologies and conventional HVDC topology
Authors: Lou Boliang , Zhou Hua , Xu Zheng , Wang Shijia , Xu Yuzhe
Published: October 2018

The modular multilevel converter (MMC) can be used to upgrade conventional line commutated converter‐based HVDC systems (LCC‐HVDC), construct the hybrid topologies of LCC and MMC to acquire better fault responses. In this study, the mechanisms of three kinds of hybrid topologies for dc fault clearance are firstly analysed. Then the fault responses of the three hybrid topologies and the conventional LCC‐HVDC topology are detailedly compared, including dc line fault and ac faults at both rectifier side and inverter side. The comparison helps demonstrate the degree of improvement when MMC is adopted to upgrade the conventional LCC‐HVDC.
Power gird interconnection with HVDClink in Northeast Asia considering complementarity of renewable energy and time zone difference
Authors: Fan Jiajie , Wang Xiuli , Huang Qihang , Zhang Xiaoliang , Li Yan , Zeng Pingliang
Published: October 2018

Facing serious environment problem and unbalanced distribution of energy resources, power grid interconnection is thought to be a significant way to the effective utilisation of renewable energy. High penetration of renewable energy brings a lot of problems to the planning and operation of power system. Considering seasonal and diurnal scales, wind and solar energy are complementary. In this study, a power gird interconnection model using linear programming techniques to minimise overall system costs was proposed, using high‐voltage direct current (HVDC) to link the power systems in Northeast Asia in view of the difference in the countries' power system. The model not only considers generation and transmission extensions, but also sets the cross border power flows. To carbon emission reduction and fuel cost saving, four power grid interconnection programmes in Northeast Asia have been setup. The results show that power grid interconnection can bring environment and economic benefits.
Preliminary reliability evaluation for power system considering geomagnetic data
Authors: Guo Mingda , Kang Xiaoning , Xu Yini , Zhao Chong , Zhang Yagang
Published: October 2018

With the increment of grid complexity and voltage level, the effect of geomagnetic induced current (GIC) on the grid is also increasing. There is no complete system to assess the impact of GIC on the reliability of the grid at present. This paper discusses the relationship between geomagnetic data and transformer failure rate. Referring to the existing mathematical model between GIC indices and failure rate, Monte–Carlo method is used to calculate the reliability of a given system under the influence of geomagnetic storm. The case study shows the validity of the assessment and this paper contributes to the establishment of a complete reliability evaluation system.
Optimisation of a lithium‐ion battery package based on heat flow field analysis
Authors: Yuan Zheng , Zhao Jin , Huang Fuxia
Published: October 2018

A lithium‐ion battery package model was established. The influence of inlet velocity, inlet angle and battery space on the heat dissipation capacity of the lithium‐ion battery pack was studied by the method of computational fluid dynamics. The single factor analysis and orthogonal test were used to optimise the lithium‐ion battery package. The results showed that the best cooling effect was obtained under the conditions of 15 m/s wind speed, 8° inlet angle and equal battery spacing; the maximum temperature and temperature difference were reduced by 11.81% and 35%, respectively.
Behaviour of unimorph ring‐shaped piezoelectric actuator in fluidic valve
Authors: Wang XuDong , Li Guoxiu , Chen Jun , Zhang Tao
Published: October 2018

This article focuses on the behaviour analysis of an unimorph ring‐shaped piezoelectric plate that is used as an actuator in a fluidic valve. First, the system modelling is discussed by using the material mechanical properties of the piezoelectric plate and the non‐piezoelectric substrate. That is, two differential equations are established for the displacements along the radial and transverse directions. After that, based on the clamped edge conditions, the transverse displacement solution is obtained as an explicit function of the applied voltage. On this basis, the analytical relationship between the transverse displacement and the applied voltage is displayed. Finally, three different voltages are applied to the ring‐shaped piezoelectric plate of a fluidic valve. The measured experimental results are almost consistent to the analytical results, which illustrates the validity of the established system model.
Hydraulic system fault diagnosis method based on a multi‐feature fusion support vector machine
Authors: Wang Lihua , Wu Xiao‐qiang , Zhang Chunyou , Shi Hongyan
Published: October 2018

Real‐time fault prevention and diagnosis in hydraulic systems is one of the challenges in engineering applications. In order to solve the problems of feature extraction and pattern recognition of different types of fault signals such as leakage, blockage, and cavitation in the hydraulic system, this paper presents a fault diagnosis method based on a multi‐feature fusion support vector machine. This method first extracts the typical features of the fault signal from the time domain, frequency domain, and time−frequency domain. Then use the information entropy to calculate the weight of each feature, select the feature with the larger weight to participate in the stock index diagnosis. Finally, a multi‐classifier based on the support vector machine is used to realise the fault diagnosis of the hydraulic system. The experimental results show that this method can achieve high accuracy in the hydraulic system fault diagnosis when the Gaussian radial basis function is selected. Also, compared with the commonly used improved back‐projection neural network fault diagnosis method, this method has more excellent diagnostic performance.
Dielectric and thermal properties of micro/nano boron nitride co‐filled EPDM composites for high‐voltage insulation
Authors: Nazir Muhammad Tariq , Phung Bao Toan , Zhang Yuanyuan , Li Shengtao
Published: October 2018

Ethylene propylene diene monomer (EPDM) is a polymeric material widely used for high‐voltage insulation. This work reports the dielectric and thermal properties of EPDM co‐filled with micro‐ and nano‐BN particles. EPDM composite samples with different micro and micro/nano co‐filled contents are prepared by melt‐blending and followed by hot press application. Measurements were made including broadband dielectric spectroscopy, thermogravimetric analysis and thermal conductivity. Experimental findings indicate that Micro‐25 wt% + Nano‐5 wt% performs better in terms of dielectric loss and conductivity whilst the dielectric constant is measured lower in Micro‐29 wt% + Nano‐1 wt% relative to the equivalent micron filled Micro‐30 wt%. Moreover, the initial degradation temperature and final residual masses of co‐filled composites are found considerably higher. The thermal conductivity of EPDM is highly influenced by the introduction of co‐filled set of particles and it is measured about 0.465 W/m.K in Micro‐29 wt% + Nano‐1 wt% which is 18% higher than Micro‐30 wt%. It is likely that the denser packing geometry due to co‐filled set of particles inside the EPDM matrix improves the dielectric and thermal properties which make such composites more attractive for electrical insulation applications.
Study on the performance of temperature‐stabilised flexible strain sensors based on silver nanowires
Authors: Du Yi , Zhang Qiang , Zhuo Kai , Ji Jianlong , Yuan Zhongyun , Ji Chao , Zhang Wendong , Sang Shengbo
Published: October 2018

Nowadays, flexible strain sensors applied in the fields of health care and electronic skin have been widely studied and applied. In fact, the temperature characteristic of flexible strain sensors based on metal nanomaterials is rarely concerned. In this work, the ohmic and tensile properties of the flexible strain sensor based on silver nanowires–polydimethylsiloxane were tested and it was found that the sensor has good ohmic characteristics and a maximum gauge factor of 536.98. In addition, the resistance of the sensor was affected little by temperature when the temperature environment of the sensor was changed, and the resistance temperature coefficient of the flexible strain sensor is −1050 ppm/°C. Furthermore, it was found that the sensor was sensitive to minute strain when the sensors were applied to the two application tests of strain and pulse.
Refluxing synthesis of Mn‐doped ZnO nanoparticles and their applications in dielectric ceramics
Authors: Zhao Ye , Tong Fan , Yang Rong , Qu Xiao , Wang Mao‐Hua
Published: October 2018

Pure and manganese (Mn)‐doped zinc oxide (ZnO) (0, 1, 2 and 4 wt%) nanoparticles are synthesised by refluxing method. The as‐synthesised nanoparticles are characterised by X‐ray powder diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and energy‐dispersive X‐ray spectroscopy (EDS). The results show that pure and Mn‐doped ZnO nanoparticles have a hexagonal wurtzite structure and the (101) diffraction peaks position of Mn‐doped ZnO shift toward the smaller value of diffraction angle compared with pure ZnO powders, confirming that the Mn2+ were well incorporated into ZnO crystal lattice. Moreover, Mn doping also restrained the growth of particles and the size decreased from 14.9244 to 13.1196 nm with the increase in doping concentration from 0 to 4 wt%. The EDS analysis for 2 wt% Mn‐doped ZnO confirms the presence of Mn in ZnO nanocrystal. The dielectric measurements show that Mn‐doped ZnO ceramics exhibit higher dielectric constant, while dielectric constant and dielectric loss increased continuously with the temperature increased. In addition, 2 wt% Mn‐doped ZnO ceramics showed the high dielectric constant (23 × 103) and low dielectric loss (0.95) at 125°C after sintering at 1000°C for 2 h.
Matrix-propagator approach to compute fluid Love numbers and applicability to extrasolar planets
Authors: Padovan S. , Spohn T. , Baumeister P. , Tosi N. , Breuer D. , Csizmadia Sz. , Hellard H. , Sohl F.
Published: October 2018

Context.The mass and radius of a planet directly provide its bulk density, which can be interpreted in terms of its overall composition. Any measure of the radial mass distribution provides a first step in constraining the interior structure. The fluid Love numberk2provides such a measure, and estimates ofk2for extrasolar planets are expected to be available in the coming years thanks to improved observational facilities and the ever-extending temporal baseline of extrasolar planet observations.

Aims.We derive a method for calculating the Love numbersknof any object given its density profile, which is routinely calculated from interior structure codes.

Methods.We used the matrix-propagator technique, a method frequently used in the geophysical community.

Results.We detail the calculation and apply it to the case of GJ 436b, a classical example of the degeneracy of mass-radius relationships, to illustrate how measurements ofk2can improve our understanding of the interior structure of extrasolar planets. We implemented the method in a code that is fast, freely available, and easy to combine with preexisting interior structure codes. While the linear approach presented here for the calculation of the Love numbers cannot treat the presence of nonlinear effects that may arise under certain dynamical conditions, it is applicable to close-in gaseous extrasolar planets like hot Jupiters, likely the first targets for whichk2will be measured.
Modélisation conceptuelle de la gestion adaptative de la biomasse face à l’aléa climatique en systèmes agro-sylvopastoraux
Authors: Grillot Myriam , Vayssières Jonathan , Guerrin François , Lecomte Philippe
Published: October 2018

Le recyclage de la biomasse végétale et animale joue un rôle central dans le fonctionnement des systèmes agro-sylvopastoraux. En Afrique de l’Ouest, la variabilité des précipitations impacte les pratiques de gestion de cette biomasse pour nourrir les hommes, le bétail, le sol et les plantes. Cette étude décrit un modèle d’action conceptuel basé sur des règles ≪ si-alors-sinon » qui représentent les décisions de gestion de la biomasse des ménages agricoles. L’étude souligne les conséquences en cascade d’un aléa pluviométrique sur le calendrier des activités agricoles, les quantités et la nature des biomasses mobilisées. Les activités les plus directement impactées sont le semis et la récolte des cultures, l’alimentation animale et, indirectement, la fertilisation des sols et la gestion des stocks alimentaires. Le modèle d’action regroupe les principales règles et modalités de gestion constituant les pratiques des ménages agricoles. Il est défini pour quatre types de ménages agriculture-élevage selon leurs activités dominantes : agricultureversusélevage et vivrierversusvente. Les ménages vivriers et élevage sont plus sensibles aux variations pluviométriques. Ils présentent une gestion plus adaptative car ils sont davantage dépendants de leur propre production. Ce modèle d’action a été conçu en vue de son intégration dans un modèle à base d’agents pour simuler les conséquences de l’aléa pluviométrique sur les flux de biomasses résultant des interactions entre les ménages agricoles d’une communauté villageoise en Afrique de l’Ouest.
L’immersion pour l’appréhension des outils de modélisation paramétrique en conception architecturale
Authors: Stals Adeline , Elsen Catherine , Jancart Sylvie
Published: October 2018

L’évolution des besoins des architectes en matière d’outils de conception les a poussés à adopter et adapter des outils d’abord dédiés à d’autres secteurs. Certains de ces outils dits paramétriques sont davantage utilisés dans les grands bureaux d’architecture que dans les petites agences, qui représentent pourtant la majorité des acteurs de la conception architecturale (Stals et al., 2017). Le papier se concentre dès lors sur l’analyse du ressenti d’architectes intégrés à ces plus petites structures et participant à une journée de formation. Leur appréhension des outils de modélisation paramétrique est évaluée comparativement en début et en fin de formation selon trois attributs émergeant tant de la littérature que de leurs propres réponses. L’article développe donc les résultats selon trois attributs : créativité, aspects techniques, fonctionnalités. La pertinence de l’usage de tels outils dans de petites structures est également discutée.
Stratégies de prospect du droit solaire par l’immersion
Authors: Koubaa Turki Laila , Raboudi Khaoula , Ben Saci Abdelkader
Published: October 2018

Cet article propose des stratégies du droit solaire basées sur l’optimisation du temps de coupure d’ombrage et des clôtures d’ombres. Il vise à minimiser l’empreinte carbone des bâtiments en exploitant au mieux les ressources utiles du contexte, notamment le parcellaire. Il propose la notion du retrait propre pour restreindre l’ombre à l’intérieur de la parcelle pendant le temps de coupure d’ombrage. Le retrait propre mutualisé par la négociation entre voisins optimise le potentiel solaire et la densité urbaine. Il sert à établir une réglementation urbaine dynamique qui se base sur l’immersion via une maquette numérique paramétrique. Celle-ci permet de définir des nouvelles stratégies de droit solaire favorisant à la fois la densification urbaine et une meilleure exploitation des ressources utiles de l’environnement.
Essential Oils as Treatment Strategy for Alzheimerʼs Disease: Current and Future Perspectives
Authors: Benny Anju , Thomas Jaya
Published: October 2018

Alzheimerʼs disease is a multifarious neurodegenerative disease that causes cognitive impairment and gradual memory loss. Several hypotheses have been put forward to postulate its pathophysiology. Currently, few drugs are available for the management of Alzheimerʼs disease and the treatment provides only symptomatic relief. Our aim is to review the relevant in vitro, in vivo, and clinical studies focused toward the potential uses of essential oils in the treatment of Alzheimerʼs disease. Scientific databases such as PubMed, ScienceDirect, Scopus, and Google Scholar from April 1998 to June 2018 were explored to collect data. We have conducted wide search on various essential oils used in different models of Alzheimerʼs disease. Out of 55 essential oils identified for Alzheimerʼs intervention, 28 have been included in the present review. A short description of in vivo studies of 13 essential oils together with clinical trial data of Salvia officinalis, Salvia lavandulifolia, Melissa officinalis, Lavandula angustifolia, and Rosmarinus officinalis have been highlighted. In vitro studies of remaining essential oils that possess antioxidant and anticholinesterase potential are also mentioned. Our literary survey revealed encouraging results regarding the various essential oils being studied in preclinical and clinical studies of Alzheimerʼs disease with significant effects in modulating the pathology through anti-amyloid, antioxidants, anticholinesterase, and memory-enhancement activity.
Organocatalytic Allylic Amination of Morita–Baylis–Hillman Carbonates­
Authors: Veselý Jan , Formánek Bedřich , Šimek Michal , Kamlar Martin , Císařová Ivana
Published: October 2018

An organocatalytic asymmetric allylic amination of Morita–Baylis–Hillman carbonates with aromatic amines in the presence of β-isocupreidine is described. Chiral allylic amines were obtained in almost quantitative yields (90–96%) with moderate enantioselectivity. Recrystallization afforded products in good yields (45–73%) and high optical purity (82–99% ee). This method provides a facile and efficient route to obtain optically active β-lactams, including the building block of the cholesterol-lowering drug Ezetimibe.