bluuebunny/crossref_metadata_2025 huggingface dataset:
Spiro-fused bis-hexa-peri-hexabenzocoronene
Authors: Hu Yunbin , Wang Di , Baumgarten Martin , Schollmeyer Dieter , Müllen Klaus , Narita Akimitsu
Published: October 2018

A spiro-fused hexa-peri-hexabenzocoronene dimer is first prepared, which is confirmed by X-ray crystallography, exhibiting reversible redox property.
Hollow carbon anchored highly dispersed Pd species for selective hydrogenation of 3-nitrostyrene: metal-carbon interaction
Authors: Lou Yang , Xu Jia , Wu Honglu , Liu Jingyue
Published: October 2018

Hollow nanocarbon supported Pd species are highly active (TOF of 21 845 h−1), selective (97%), and stable (4 cycles) for selective hydrogenation of 3-nitrostyrene to 3-ethylnitrobenze.
Nickel-catalyzed intermolecular carboiodination of alkynes with aryl iodides
Authors: Takahashi Toshifumi , Kuroda Daiki , Kuwano Toru , Yoshida Yuji , Kurahashi Takuya , Matsubara Seijiro
Published: October 2018

Odd-valent nickel-catalyzed intermolecular carboiodination of alkynes with aryl iodides to form highly substituted and functionalized alkenyl iodides has been developed.
Selective photooxidation of sulfides mediated by singlet oxygen using visible-light-responsive coordination polymers
Authors: Liang Xiao , Guo Zhifen , Wei Hongxia , Liu Xin , Lv Hui , Xing Hongzhu
Published: October 2018

A novel visible-light-responsive coordination polymer for highly selective photooxidation of sulfides to produce sulfoxides through singlet oxygen species.
Three-dimensional supramolecular polymerization based on pillar[n]arenes (n = 5, 6) and halogen bonding interactions
Authors: Han Chengyou , Zhao Dezhi , Dong Shengyi
Published: October 2018

Three dimensional supramolecular polymerization networks based on pillar[5,6]arenes were constructed both in solution and in the solid state.
5-Formyluracil as a cornerstone for aluminum detectionin vitroandin vivo: a more natural and sustainable strategy
Authors: Zou Guangrong , Liu Chaoxing , Cong Chen , Fang Zhentian , Yang Wei , Luo Xiaomeng , Jia Shaokang , Wu Fan , Zhou Xiang
Published: October 2018

5-Formyluracil (5fU) based probes were designed and synthesized to detect Al3+ionsin vitroand in biological systems.
Synthesis of NaA zeolite membrane by maintaining pressure difference between the two sides of the support
Authors: Wei Xue-Ling , Liu Huan , Xu Yao-Yi , Sun Ya-Li , Chao Zi-Sheng
Published: October 2018

Pressure difference assists more Si/Al active ingredient migration to the surface of the support and thus facilitates the formation of uniform and dense zeolite membranes.
Synthesis of size-controlled UO2 microspheres from the hydrothermal conversion of U(iv) aspartate
Authors: Trillaud V. , Maynadié J. , Manaud J. , Hidalgo J. , Meyer D. , Podor R. , Dacheux N. , Clavier N.
Published: October 2018

A wet chemistry route towards UO2 spherical particles was designed through the hydrothermal conversion of uranium(iv) aspartate. A multi-parametric study led us to point out the conditions leading to monodisperse and size-controlled particles in the 400–2500 nm range. This simple protocol paves the way to applications in various scientific areas.
On the crystallization behavior of a poly(stearyl methacrylate) comb-like polymer inside a nanoscale environment
Authors: Li Shuqin , Wang Haixia , Liu Luntao , Xu Hongxing , Shi Haifeng
Published: October 2018

A “soft” or “hard” nanoscale template illustrates the confined processes of a poly(stearyl methylacrylate) comb-like polymer, indicating that reduced chain relaxation and mobility influence the crystallization behavior.
Deprotonated carbohydrate anion fragmentation chemistry: structural evidence from tandem mass spectrometry, infra-red spectroscopy, and theory
Authors: Rabus Jordan M. , Simmons Daniel R. , Maître Philippe , Bythell Benjamin J.
Published: October 2018

We investigate the gas-phase structures and fragmentation chemistry of deprotonated carbohydrate anions using combined tandem mass spectrometry, infrared spectroscopy, regioselective labelling, and theory.
Ligand field effects on the ground and excited states of reactive FeO2+ species
Authors: Kirkland Justin K. , Khan Shahriar N. , Casale Bryan , Miliordos Evangelos , Vogiatzis Konstantinos D.
Published: October 2018

Multiconfigurational quantum chemical calculations on bare and representative ligated iron oxide dicationic species suggest that weak ligand fields promote more reactive channels, whereas strong ligand fields stabilize the less reactive iron-oxo structure.
Interrogating the effects of ion-implantation-induced defects on the energy storage properties of bulk molybdenum disulphide
Authors: Mwonga Patrick V. , Barik Rasmita , Naidoo Shunmugam R. , Quandt Alex , Ozoemena Kenneth I.
Published: October 2018

Under similar experimental conditions, W-ion-implanted MoS2 exhibits enhanced electrochemistry compared to the Mo-ion-implanted MoS2 counterpart.
Freezing of micrometer-sized liquid droplets of pure water evaporatively cooled in a vacuum
Authors: Ando Kota , Arakawa Masashi , Terasaki Akira
Published: October 2018

The freezing time of pure-water droplets is measured in a vacuum and simulated by ice nucleation theory.
Interpreting the Raman OH/OD stretch band of ice from isotopic substitution and phase transition effects
Authors: Hu Qingcheng , Zhao Haiwen , Ouyang Shunli
Published: October 2018

A unified interpretation of the Raman spectral features of ice and liquid water based on diversity of HB configurations.
Synthesis and improved photoluminescence of hexagonal crystals of Li2ZrF6:Mn4+ for warm WLED application
Authors: Zhang Lei , Xi Luqing , Pan Yuexiao , Jia Yajun , Wu Mingmei , Lian Hongzhou , Lin Jun
Published: October 2018

A novel red phosphor Li2ZrF6:Mn4+ being promising for application in WLEDs has been synthesized for the first time by the ion-exchange method at room temperature, and its luminescence intensity has been optimized.
The use of a semi-flexible bipyrimidyl ligand for the construction of azide-based coordination polymers: structural diversities and magnetic properties
Authors: Zhang Zu-Zhen , Lee Gene-Hsiang , Yang Chen-I
Published: October 2018

The use of a semi-flexible bipyrimidyl ligand, 5,5′-bipyrimidine, afforded four new 2D and 3D azide-based coordination polymers with diverse structures and magnetic properties.
Nanomaterial identification of powders: comparing volume specific surface area, X-ray diffraction and scanning electron microscopy methods
Authors: Dazon Claire , Witschger Olivier , Bau Sébastien , Fierro Vanessa , Llewellyn Philip L.
Published: October 2018

This work shows that the volume specific surface area could be a reliable criterion for nanomaterial identification.
Biodegradation of acid dyes by an immobilized laccase: an ecotoxicological approach
Authors: Gioia Larissa , Ovsejevi Karen , Manta Carmen , Míguez Diana , Menéndez Pilar
Published: October 2018

An efficient degradation of two azo dyes by the immobilized laccase ofTrametes villosaand its ecotoxicological assessment are reported.
An ambient-temperature aqueous synthesis of zirconium-based metal–organic frameworks
Authors: Pakamorė Ignas , Rousseau Jolanta , Rousseau Cyril , Monflier Eric , Szilágyi Petra Ágota
Published: October 2018

Illustration of the first ambient-temperature aqueous synthesis of the zirconium-based metal–organic framework NH2-UiO-66.
Hetero-bifunctional catalyst manipulates carbonyl and alkynyl reductions of conjugated alkynones in an aqueous medium
Authors: Su Yanchao , Chang Fengwei , Jin Ronghua , Liu Rui , Liu Guohua
Published: October 2018

A yolk–shell-mesostructured silica-supported active site-isolated catalyst controllably manipulates carbonyl and alkynyl reductions of conjugated alkynones.
Noble metal-free upgrading of multi-unsaturated biomass derivatives at room temperature: silyl species enable reactivity
Authors: Li Hu , Zhao Wenfeng , Dai Wenshuai , Long Jingxuan , Watanabe Masaru , Meier Sebastian , Saravanamurugan Shunmugavel , Yang Song , Riisager Anders
Published: October 2018

A simple and robust catalytic system is described for the controllable conversion of biomass-derived chemicals.
Microfluidic bead encapsulation above 20 kHz with triggered drop formation
Authors: Clark Iain C. , Abate Adam R.
Published: October 2018

Bead-triggered breakup of a fluid jet into monodispersed droplets improves the throughput of bead-based droplet workflows, enabling the analysis of large populations and the detection of rare events.
Screening of the Pathogen Box reveals new starting points for anti-trypanosomal drug discovery
Authors: Veale Clinton G. L. , Hoppe Heinrich C.
Published: October 2018

This study has identified several compounds with potential for repurposing against Trypanosoma brucei.
Aggregation behavior of sodium 3-(octyloxy)-4-nitrobenzoate in aqueous solution
Authors: Soto Victor H. , Vázquez-Tato M. Pilar , Meijide Francisco , Alvarado María José , Seijas Julio A. , de Frutos Santiago , Lomonte Bruno , Vázquez Tato José
Published: October 2018

3-(Octyloxy)-4-nitrobenzoate, a PLA2 inhibitor, is a better surfactant than other octyl derivatives and can be used as a model for 3-(octanoyloxy)-4-nitrobenzoic acid.
Multi-responsive luminescent sensor based on three dimensional lanthanide metal–organic framework
Authors: Tao Yufang , Zhang Ping , Liu Junning , Chen Xiaodong , Guo Xiuli , Jin Haoqing , Chai Juan , Wang Li , Fan Yong
Published: October 2018

A novel multi-functional luminescent MOF was synthesized, which shows excellent recyclable luminescent sensing for acetone, Fe3+, Cr2O72− and 4-NP.
Effect of preparation temperature on the structures and hydrodeoxygenation performance of Ni2P/C catalysts prepared by decomposition of hypophosphites
Authors: Dai Xueya , Song Hua , Yan Zijin , Li Feng , Chen Yanguang , Wang Xueqin , Yuan Dandan , Zhang Jiaojing , Wang Yuanyuan
Published: October 2018

A novel method for preparing Ni2P/C-x catalysts was proposed. The structure and hydrodeoxygenation performance of Ni2P/C-x catalysts were investigated.
Bodipy-based chemosensors for highly sensitive and selective detection of Hg2+ ions
Authors: Sun Wei , Chen Rong , Cheng Xinjian , Marin Luminita
Published: October 2018

Small molecular chemo-sensors with strong fluorescence were designed and synthesized. Then, corresponding macromolecular sensors were synthesized by introducing the as-prepared small molecular sensors. The macromolecular chemo-sensors not only retained their sensing ability, but also enhanced the sensing ability dramatically.
Measurement of cytokine biomarkers using an aptamer-based affinity graphene nanosensor on a flexible substrate toward wearable applications
Authors: Hao Zhuang , Wang Ziran , Li Yijun , Zhu Yibo , Wang Xuejun , De Moraes Carlos Gustavo , Pan Yunlu , Zhao Xuezeng , Lin Qiao
Published: October 2018

We present an approach for the label-free detection of cytokine biomarkers using an aptamer-functionalized, graphene field effect transistor (GFET) nanosensor on a flexible, SiO2-coated polymer polyethylene naphthalate (PEN).
On-surface transmetalation of metalloporphyrins
Authors: Hötger Diana , Abufager Paula , Morchutt Claudius , Alexa Patrick , Grumelli Doris , Dreiser Jan , Stepanow Sebastian , Gambardella Pietro , Busnengo H. Fabio , Etzkorn Markus , Gutzler Rico , Kern Klaus
Published: October 2018

Experimental and computational data sheds light onto the metal exchange in porphyrin monolayers.
The relationship between the laser damaged threshold and step velocity in different supersaturation regions
Authors: Li Weidong , Li Yu , Wang Shenglai , Cheng Wenyong
Published: October 2018

The laser damaged threshold (LDT) of potassium dihydrogen phosphate (KDP) crystals grown at different supersaturation points were investigated using a Nd:YAG nanosecond laser.
Highly efficient uranium adsorption by salicylaldoxime/polydopamine graphene oxide nanocomposites
Authors: Qian Yongxin , Yuan Yihui , Wang Heliang , Liu Hu , Zhang Jiaoxia , Shi Se , Guo Zhanhu , Wang Ning
Published: October 2018

Polydopamine/oxime-functionalized nanostructures demonstrated a maximum uranium adsorption capability up to 1049 mg g−1 owing to the synergy between PDA and salicylaldoxime.
Dimerization of the Trk receptors in the plasma membrane: effects of their cognate ligands
Authors: Ahmed Fozia , Hristova Kalina
Published: October 2018

Receptor tyrosine kinases (RTKs) are cell surface receptors which control cell growth and differentiation, and play important roles in tumorigenesis. Despite decades of RTK research, the mechanism of RTK activation in response to their ligands is still under debate. Here, we investigate the interactions that control the activation of the tropomyosin receptor kinase (Trk) family of RTKs in the plasma membrane, using a FRET-based methodology. The Trk receptors are expressed in neuronal tissues, and guide the development of the central and peripheral nervous systems during development. We quantify the dimerization of human Trk-A, Trk-B, and Trk-C in the absence and presence of their cognate ligands: human β-nerve growth factor, human brain-derived neurotrophic factor, and human neurotrophin-3, respectively. We also assess conformational changes in the Trk dimers upon ligand binding. Our data support a model of Trk activation in which (1) Trks have a propensity to interact laterally and to form dimers even in the absence of ligand, (2) different Trk unliganded dimers have different stabilities, (3) ligand binding leads to Trk dimer stabilization, and (4) ligand binding induces structural changes in the Trk dimers which propagate to their transmembrane and intracellular domains. This model, which we call the ‘transition model of RTK activation,’ may hold true for many other RTKs.
Multi‐task learning for captioning images with novel words
Authors: Zheng He , Wu Jiahong , Liang Rui , Li Ye , Li Xuzhi
Published: October 2018

Recent captioning models are limited in their ability to describe concepts unseen in paired image–sentence pairs. This study presents a framework of multi‐task learning for describing novel words not present in existing image‐captioning datasets. The authors’ framework takes advantage of external sources‐labelled images from image classification datasets, and semantic knowledge extracted from the annotated text. They propose minimising a joint objective which can learn from these diverse data sources and leverage distributional semantic embeddings. When in the inference step they change the BeamSearch step by considering both the caption model and language model enabling the model to generalise novel words outside of image‐captioning datasets. They demonstrate that in the framework by adding an annotated text data which can help the image captioning model to describe images with the right corresponding novel words. Extensive experiments are conducted on both AI Challenger and Microsoft coco (MSCOCO) image captioning datasets of two different languages, demonstrating the ability of their framework to describe novel words such as scenes and objects.
Salient object detection via reliable boundary seeds and saliency refinement
Authors: Wu Xiyin , Ma Xiaodi , Zhang Jinxia , Jin Zhong
Published: October 2018

Salient object detection can identify the most distinctive objects in a scene. In this study, a novel graph‐based approach is proposed to detect a salient object via reliable boundary seeds and saliency refinement. A natural image is firstly mapped to a graph with superpixels as nodes. Saliency information is then diffused over the graph using seeds. For the reason that the boundary nodes may contain salient nodes, it is not appropriate to use all boundary nodes as the background seeds. Therefore, a boundary saliency measurement is proposed to obtain more accurate background seeds. After that, the information of background seeds is diffused by a two‐stage scheme. A background‐based map and a foreground‐based map are generated based on the two‐stage scheme. Furthermore, in order to enhance the detection accuracy, a refinement model is presented to fuse the information of background‐based and foreground‐based maps. Experiments on seven public datasets show the proposed algorithm out‐performs the state‐of‐the‐art salient object detection algorithms.
Multi‐view registration based on weighted LRS matrix decomposition of motions
Authors: Jin Congcong , Zhu Jihua , Li Yaochen , Pang Shanmin , Chen Lei , Wang Jun
Published: October 2018

Recently, the low‐rank and sparse (LRS) matrix decomposition has been introduced as an effective mean to solve the multi‐view registration. It views each available relative motion as a block element to reconstruct one sparse matrix, which then is used to approximate the low‐rank matrix, where global motions can be recovered for multi‐view registration. However, this approach is sensitive to the sparsity of the reconstructed matrix and it treats all block elements equally in spite of their varied reliabilities. Therefore, this study proposes an effective approach for multi‐view registration by weighted LRS matrix decomposition. On the basis of the inverse symmetry property of relative motions, it first proposes a completion method to reduce the sparsity of the reconstructed matrix. The reduced sparsity of the reconstructed matrix can improve the robustness and efficiency of LRS matrix decomposition. Then, it proposes the weighted LRS matrix decomposition, where each block element is assigned with one estimated weight to denote its reliability. By introducing the weight, more accurate registration results can be efficiently recovered from the estimated low‐rank matrix. Experimental results tested on public datasets illustrate the superiority of the proposed approach over the state‐of‐the‐art approaches on robustness, accuracy and efficiency.
Real‐time face recognition based on pre‐identification and multi‐scale classification
Authors: Min Weidong , Fan Mengdan , Li Jing , Han Qing
Published: October 2018

In face recognition, searching a person's face in the whole picture is generally too time‐consuming to ensure high‐detection accuracy. Objects similar to the human face or multi‐view faces in low‐resolution images may result in the failure of face recognition. To alleviate the above problems, a real‐time face recognition method based on pre‐identification and multi‐scale classification is proposed in this study. The face area is segmented based on the proportion of human faces in the pedestrian area to reduce the search range, and faces can be robustly detected in complicated scenarios such as heads moving frequently or with large angles. To accurately recognise small‐scale faces, the authors propose the multi‐scale and multi‐channel shallow convolution network, which combines a multi‐scale mechanism on the feature map with a multi‐channel convolution network for real‐time face recognition. It performs face matching only in the pre‐identified face areas instead of the whole image, therefore it is more efficient. Experimental results showed that the proposed real‐time face recognition method detects and recognises faces correctly, and outperforms the existing methods in terms of effectiveness and efficiency.
Multi‐objective model predictive control of doubly‐fed induction generators for wind energy conversion
Authors: Hu Jiefeng , Li Yong , Zhu Jianguo
Published: October 2018

As large‐scale integration of wind systems into the power grid is on the rise, advanced control techniques for wind power generators are highly desired. This paper proposes a simple but effective control technique for doubly fed induction generators (DFIGs) based on the multi‐objective model predictive control (MOMPC) scheme. The future behaviors of the DFIGs are predicted by using the system model and the possible converter switching states. The most appropriate vector is then determined by a cost function. By properly modifying the cost function with active and reactive powers as the control objectives, fast grid synchronisation, smooth grid connection, flexible power regulation and maximum power point tracking (MPPT) can be achieved, respectively. In order to reduce the switching frequency for switching loss reduction, a nonlinear constraint is integrated into the cost function. The controller is simple without using any Proportion Integration (PI) regulators, current loops, and switching tables. A numerical simulation of a 2MW system based on MATLAB/Simulink is built to verify the effectiveness of the proposed method. The results show that the proposed method can achieve quicker transient response, better steady‐state performance, and lower switching frequency compared to the conventional switching table based direct power control (DPC).
Adaptive appearance separation for interactive image segmentation based on Dense CRF
Authors: Peng Zili , Li Qiaoliang
Published: October 2018

Interactive segmentation has recently become a hot topic for its wide application. The authors propose an efficacious appearance separation model for interactive binary segmentation, which incorporates the difference of foreground and background colour models and the difference of corresponding geodesic models into the popular densely connected conditional random field (Dense CRF) framework. The proposed method can adaptively set relevant parameter values in this framework according to the characteristics of target images in a per‐image manner, therefore, it gets rid of the dependence on specific datasets. After accomplishing a mean‐field inference, the authors are able to get satisfactory results without the time‐consuming parameter learning process and multiple iterative optimisations. Overall, the proposed approach is highly efficient and mitigates the contradiction between accuracy and segmentation efficiency. In addition, the proposed approach reduces the efforts of scribble‐style interaction from users. The experimental results on three famous datasets show that the proposed method is superior to the other five new algorithms released in recent years regarding accuracy, and is faster than or close to them in runtime.
Novel image encryption algorithm based on improved logistic map
Authors: Li Renzhi , Liu Qian , Liu Lingfeng
Published: October 2018

Chaotic mapping has been widely used in image encryption given the unpredictability, ergodicity, and sensitivity of parameters and initial values and the high correspondence with cryptography. The logistic map has the disadvantages of uneven distribution, low security, and small parameter space. In order to overcome these disadvantages, in this article, a new chaotic map based on a real‐time variable logistic map with a randomly selected decimal is proposed. Furthermore, this chaotic mapping is applied to image encryption. Several simulation experiments show that the new encryption algorithm can obtain a safely encrypted image at a minimal time complexity.
Efficient deactivation of unused LCC inverter for multiple transmitter wireless power transfer
Authors: Kim Woojong , Ahn Dukju
Published: October 2018

The study addresses the difficulties in deactivating an unused transmitter (TX) element for a multiple‐transmitter wireless power system that is driven by LCC resonant inverters. One difficulty of TX deactivation is a high‐level of unwanted circulating current in unused TX coil, which increases the losses in unused TX. To suppress the unwanted current without the aid of high‐voltage isolated switches and detuning capacitors, it is proposed that low‐side switches in LCC bridge should be constantly turned on. The other difficulty is the runtime detuning of LCC resonant inverter in response to the activation or deactivation status of adjacent TX coil, which degrades the LCC inverter efficiency. A tuning switch and capacitor cannot directly be inserted at the LCC resonant path due to high‐voltage stress and complex driving scheme. Instead, this study proposes a loop that adjusts the effective inductance of the TX coil with low‐voltage stress and easy gate driving, thereby increasing the LCC inverter efficiency. The loop also provides an additional power path towards the receiver so that the coil‐to‐coil efficiency is also increased.
Fault case analysis and simulation research of neutral‐bus arresters multi‐column parallel connected in converter station
Authors: Wang Dianlang , Li Guogen , Jiang Long , Yang Xiaowei , Pi Tianman , Huang Zhongkang , Li Dong , Zhang Jie , Yaoi Xiangyu , Su Rongyu , Zhang Lihui
Published: October 2018

High‐voltage DC arrester is one of the key equipment for overvoltage protection of ultra‐high voltage DC (UHVDC) transmission system. This device plays a decisive role in the insulation level of the whole process. The current distribution between resistance pieces of multi‐column parallel arresters is non‐uniform, which affects the overall energy absorption capacity of arresters. First, a real failure case of ±500 kV Xiluodu‐Nuozhadu HVDC project is introduced. Then, the analysis of the specific failure case is proposed. Finally, a corresponding model is built on PSCAD/EMTDC to study the current distribution characteristics.
Direct instantaneous torque control system for switched reluctance motor in electric vehicles
Authors: Liu Lijun , Zhao Mingwei , Yuan Xibo , Ruan Yi
Published: October 2018

Switch reluctance motor is suitable for an electric vehicle driving system, which has the advantages of simple structure, high reliability of system and wide range of speed adjustment. In order to reduce the torque ripple of the system and improve the dynamic performance, a strategy of direct instantaneous torque control (DITC) based on a fractional‐order proportion integration differentiation (PID) controller is proposed. According to the mathematical characteristics of the fractional‐order controller, the form of the fractional‐order speed loop controller is determined. Also, the parameters of the speed regulator are designed using the frequency‐domain design theory of the control system. Then, the fractional‐order controller is discretised. Compared with the traditional proportion integration (PI) controller, the fractional‐order controller can have a better control effect. Simulation experimental results of the system show that the DITC control method has effectively reduced the torque ripple and the fractional‐integral controller has reduced the overshoot and adjustment time and improved the robustness and disturbance resistance of the system.
Study on overvoltage of hybrid LCC‐VSC‐HVDC transmission
Authors: Xu Dizhen , Zhao Xiaobin , Lu Yuxin , Qin Kang , Guo Long
Published: October 2018

Hybrid line commutation converter‐voltage‐source converter high‐voltage direct current transmission (LCC‐VSC‐HVDC) power transmission has unique technical advantages, but its overvoltage study is not sufficient at present. In this study, the typical overvoltage phenomenon of hybrid LCC‐VSC‐HVDC power transmission is analysed and verified by power systems computer‐aided design/electro‐magnetic transient design and control simulation. On the one hand, overvoltage mechanism of modular multilevel converter module caused by single‐phase grounding fault at the valve side of VSC transformer is analysed, and arresters are configured for the protection of the valve. On the other hand, the stress of the arresters at the LCC side is analysed. Installing current reversing protection on the VSC side is proposed. The research of this study provides the recommended arresters configuration in the converter station of hybrid LCC‐VSC‐HVDC power transmission system.
Simulation and research on over‐voltage suppression for high voltage transmission line
Authors: Yao Qi , Su Chuan , Ji Yi
Published: October 2018

For different types of fault in transmission line, the generation mechanism of tripping and closing over‐voltage is analysed. To built the double power supply system of high‐voltage transmission line simulation model by PSCAD/EMTDC, finally, for the operation of over‐voltage, when the line occurs of different types faults, simulation to study tripping and closing over‐voltage's size and the extent of influence, derived its tripping and closing over‐voltage suppression measures and control strategies. The results showed that: for the circuit breaker tripping and closing over‐voltage, the circuit breaker shunt reactor has better effect on the over‐voltage suppression and improves the reliability of operation and the safety of protection of the system.
Multi‐hierarchy control strategy in abc coordinate for modular multilevel matrix converter in fractional frequency transmission system
Authors: Ou Zhujian , Wang Guangzhu
Published: October 2018

This paper proposes a multi‐hierarchy control strategy in abc coordinate for modular multilevel matrix converter (M3 C) in fractional frequency transmission system (FFTS). The proposed control strategy avoids complicated coordinate transformations when the traditional control strategies based on coordinate transformation are adopted. Four hierarchies are designed to balance the capacitor voltages. In different hierarchies, the capacitor voltage ripples have different frequencies. According to this characteristic, different bandwidths of filters are adopted in different hierarchies, resulting in different control speeds among the four hierarchies. This will not only speed up the control but also assure the control accuracy. Simulation results verify the feasibility and effectiveness of the proposed strategy.
Realisation of DC/DC high power and large current combined power supply for airborne radar
Authors: Zhang Yingying , Xu Shuiqing , Chen Zhiwei , Li Xiang , Dong Bingbing , Luo Qiwu , Li Bing , He Yiyang
Published: October 2018

With the development of radar power supply system, the power density of DC/DC power supply is becoming larger and larger, but the volume is becoming smaller and smaller, which makes the power density of the power supply increase, and the combination of power modules needs to be optimised to realise the power supply of the whole system. Here, a modular design scheme is introduced, which adopts a three‐layer combined structure, and finally realises the DC/DC combined power supply with a total power of 15.6 kW in the total height of 105 mm. The heat design of the power supply is reasonable, the rectangular liquid cooling channel is arranged inside the cooling plate of the chassis, the rectangular heat exchanger fin is added inside the liquid cooling channel with concentrated heat source, and the series‐parallel technology is used in the liquid cooling channel inside the plate. The series reliability prediction model can meet the requirements of radar overall design. The project is difficult to implement, and more precise process is needed in practical engineering to strictly control it. The successful implementation of this scheme provides a reference for the realisation of similar radar products.
Solution to reduce voltage stress of sub‐module in LCC–MMC transmission system at the condition of communication fault
Authors: Xing Dengjiang , Su Jianjun , Hu Dingwen , Sun Shumin , Chen Yan , Wang Xianwei , Zhang Jun , Yao Weizheng , Wu Jinlong
Published: October 2018

Line commutate converter–modular multilevel converter (LCC–MMC) hybrid high voltage direct current (HVDC) system combines the advantages of both LCC‐HVDC and MMC‐HVDC, and will be wildly used in the future. The sub‐module will withstand a very high voltage if a fault occurs in MMC converter station. In order to reduce this voltage, the LCC converter must operate in inversion state through gate‐shift (GS) control strategy as quickly as possible. Normally, the fault signal was sent to LCC station through communication and GS control strategy was triggered due to this signal. At the condition of communication fault, LCC converter station cannot receive a fault signal, thus the control strategy will not change. In this way, the SM voltage will be as high as 4100 V which is beyond the maximum withstanding voltage of insulated gate bipolar transistor (IGBT). It will endanger the safety of devices. To solve the over voltage problem of IGBT, a new solution that designs a leakage thyristor valve between DC line and ground is proposed as well as the coordination control strategy. A simulation based on power systems computer aided design (PSCAD) is conducted to verify this method. The simulation results show that the proposed solution is valid.
Research on the fitting method to describe the mathematical expression of VFTO in GIS
Authors: Almenweer Reem A. , Yixin Su , Xixiu Wu
Published: October 2018

Very fast transient over voltage (VFTO) is a unique electromagnetic transient phenomenon occurring in Gas Insulated Substation (GIS), which determines the insulation level of the GIS (above 330 kV). Unfortunately, up to the present, there is no standard VFTO waveform to test the high voltage equipment to ensure the safety of power grid. For this reason, this paper focuses on obtaining the standard VFTO waveform through finding a method to fit the curve of VFTO. Hence, a UHV disconnector operation experiment of GIS was carried out on the UHV GIS test platform. The representative waveform of VFTO generated by a single SF6 gas discharge was extracted from the measured data. Furthermore, The Fast Fourier Transformer is applied to analyze the frequency features of VFTO. As one of the switchgear operation voltage, VFTO can be concluded to be a superposition of the power‐frequency waveform with the non‐periodic impulse waveform. Thus, it is found that The Squares Method is convenient for fitting the expression of VFTO according to its transient characteristics. Then the standard VFTO waveform can be obtained from the fitting expression, which coincides well with the measured waveform. The simulation results using ATP‐EMTP software are compared with the calculation results and the measured results.
Research on current‐mode damping impedance interface model based on adaptive impedance matching
Authors: Keyan Liu , Xiaoli Meng , Yanshi Sun , Gaowen Zhong , Zhongjian Kang , Ruiying Liu , Zhendong Zhao
Published: October 2018

With the development and progress of new energy electricity generation technology, a detailed study and test is required on new energy power generation equipment and micro‐network system. As of the advantage of both numerical simulation and physical simulation, power connection type digital physical mixed simulation system could accomplish such research and tests. The simulation interface is the key to realise hybrid simulation. This paper proposes a current‐mode damping impedance interface model based on adaptive impedance matching. The model is analysed from the interface stability, the accuracy and the dynamic response ability according to the structure of the interface model. Both theoretical analysis and simulation results show that current‐mode damping impedance interface model based on adaptive impedance has high stability and accuracy, and also good dynamic response capability.
A unifying theory of dark energy and dark matter: Negative masses and matter creation within a modified ΛCDM framework
Authors: Farnes J. S.
Published: October 2018

Dark energy and dark matter constitute 95% of the observable Universe. Yet the physical nature of these two phenomena remains a mystery. Einstein suggested a long-forgotten solution: gravitationally repulsive negative masses, which drive cosmic expansion and cannot coalesce into light-emitting structures. However, contemporary cosmological results are derived upon the reasonable assumption that the Universe only contains positive masses. By reconsidering this assumption, I have constructed a toy model which suggests that both dark phenomena can be unified into a single negative mass fluid. The model is a modified ΛCDM cosmology, and indicates that continuously-created negative masses can resemble the cosmological constant and can flatten the rotation curves of galaxies. The model leads to a cyclic universe with a time-variable Hubble parameter, potentially providing compatibility with the current tension that is emerging in cosmological measurements. In the first three-dimensional N-body simulations of negative mass matter in the scientific literature, this exotic material naturally forms haloes around galaxies that extend to several galactic radii. These haloes are not cuspy. The proposed cosmological model is therefore able to predict the observed distribution of dark matter in galaxies from first principles. The model makes several testable predictions and seems to have the potential to be consistent with observational evidence from distant supernovae, the cosmic microwave background, and galaxy clusters. These findings may imply that negative masses are a real and physical aspect of our Universe, or alternatively may imply the existence of a superseding theory that in some limit can be modelled by effective negative masses. Both cases lead to the surprising conclusion that the compelling puzzle of the dark Universe may have been due to a simple sign error.
New ultra-cool and brown dwarf candidates in Gaia DR2
Authors: Reylé C.
Published: October 2018

Context. The second Gaia data release (Gaia DR2) contains high-precision positions, parallaxes, and proper motions for 1.3 billion sources. The resulting Hertzsprung–Russel diagram reveals fine structures throughout the mass range.

Aims. This paper aims to investigate the content of Gaia DR2 at the low-mass end and to characterize ultra-cool and brown dwarfs. Methods. We first retrieved the sample of spectroscopically confirmed ultra-cool and brown dwarfs in Gaia DR2. We used their locus in the precise Hertzsprung–Russel diagram to select new candidates and to investigate their properties.

Results. The number of spectroscopically confirmed objects recovered in Gaia DR2 corresponds to 61% and 74% of the expected number of objects with an estimated Gaia magnitude G
est ≤ 21.5 and 20.3, respectively. This fills much of the gap to Gaia DR1. Furthermore, Gaia DR2 contains Ȉ13 000 ≥ M7 and 631 new L candidates. A tentative classification suggests that a few hundred of them are young or subdwarf candidates. Their distance distribution shows that the solar neighborhood census is still incomplete.

Conclusions. Gaia DR2 offers a great wealth of information on low-mass objects. It provides a homogeneous and precise catalog of candidates that is worthwhile to be further characterized with spectroscopic observations.
Control design variable speed drive three-phase induction motor based cascaded H-Bridge seven level
Authors: Otong Muhamad , Ahendyarti Ceri
Published: October 2018

The design variable speed drive induction motor is based on the power supply system of cascaded H-bridge seven level inverter. The variable speed regulation of the induction motor is performed by controlling the variable magnitude and output voltage frequency of the CHB circuit. The output voltage of the CHB circuit is generated by synthesizing the reference voltage signal derived from the field oriented control algorithm model of the induction motor. Testing and circuit operation mode using switching phase-switch technique on variable speed drive system of induction motor is done to know system performance in transient and steady-state by using computer software. The response of the simulation shows the conformity of the proposed concept. From this research is expected to improve the quality and capacity of output power in modular way so that it can be applied to the electric drive in general.
Performance Analysis of Internet Key Exchange Algorithms on IPSec Security Association Initiation
Authors: Praptodiyono Supriyanto , Furqon Moh. , Maulana Alief , Hasbullah Iznan H. , Ul Rehman Shafiq
Published: October 2018

Naturally, the Internet as an open network allows millions of users to interact each other. Furthermore, the giant network vulnerable to various malicious activities that potentially causes many (losses) for both resources and humanity. In order to reduce the potential attacking activities, Internet Engineering Task Force has standardized a network level security so-called IP Security. The key process behind the IP Security is a Security Association that is identified by Security Parameter Index. The initiation of Security Association performance depends on the encryption algorithm used. Hence, the performance of the algorithm candidate is an important consideration. This paper aims to evaluate some encryption algorithm to be used in IPv6 network. Results of the experiments shows that ECP 384 based on the elliptic curve algorithms outperforms than the traditional algorithm such as MODP 1024 and MODP 3072.
E-Government Interoperability: Architecture Model for Public Information Services of Sub-District Governments
Authors: Er Riyanto Djalal , Wisnu Wirawan Panji , Kurniawan Kabul
Published: October 2018

Sub-District Government as a Public Bodies is such a state administrator in accordance to the law required to apply disclosure, either by publishing information proactively, and or providing information application services. Implementation of e-Government is one solution that can be used to improve performance in running the mandate of the law. E-Government requires collaboration from various Public Bodies, especially in data exchange, information sharing, and processes. E-Government Interoperability is the development of inter e-Government systems for sharing and integrating information using shared standards. The success of e-Government Interoperability is determined by strategies, policies, and architectures that enable data, information technology systems, business processes, and service lines to integrate precisely and efficiently. The architectural model generated from this study illustrates the structure of e-Government Interoperability, the basic organization of system components, the relationship of one component with other components and the environment. Model validation uses result approach/theory analysis for data standardization, solid platforms, easier access to information, and efficient administration and services. The architectural model can serve as a guide for design and evolution, in an effort to create a system for public information services, especially at the sub-district level. It was concluded that the model was able to realize the development of sub-district vertical database integration and single-sign-on.
Banten Batik Classification with Backpropagation Neural Network
Authors: Fahrizal Rian , Parlindungan Siahaan Ridwan Prasetya , Wiryadinata Romi
Published: October 2018

Batik Cloth is Indonesia heritage of the indigenous cultures. However, the lack of public awareness could made the other nations has claimed that Batik cloth as their heritage. Therefore, We will need serious attention to take the problems. The classification Banten pattern batik cloth had been made to protect the Batik pattern. The classification had been made with Artificial Neural Network with Lavender-Marquant methods. Gray-Level Co-Occurrence Matrix (GLCM) has been used to preprocessing the pattern from Gray scale images. The results showed that the Batik patterns had 97% accuracy and 2% error.
Time Series Traffic Speed Prediction Using k-Nearest Neighbour Based on Similar Traffic Data
Authors: Priambodo Bagus , Jumaryadi Yuwan
Published: October 2018

During the past few years, time series models and neural network models are widely used to predict traffic flow and traffic congestion based on historical data. Historical data traffic from sensors is often applied to time series prediction or various neural network predictions. Recent research shows that traffic flow pattern will be different on weekdays and weekends. We conducted a time series prediction of traffic flow on Monday, using data on weekdays and whole days data. Prediction of short time traffic flows on Monday based on weekdays data using k-NN methods shows a better result, compared to prediction based on all day’s data. We compared the results of the experiment using k-NN and Neural Network methods. From this study, we observed that generally, using similar traffic data for time series prediction show a better result than using the whole data.
Integration house of risk and analytical network process for supply chain risk mitigation of cassava opak chips industry
Authors: Ummi Nurul , Ferro Ferdinant Putro , Irman M.S Ade , Gunawan Akbar
Published: October 2018

Supply chain risk is difficult to predict and cause losses that will affect business growth. Supply chain management is a method used for risk control by being used in the cassava industry supply chain. This objective is to determine the risks that will occur and potentially disrupt the supply chain, to determine the risk agent sequence from the Aggregate Risk Potential (ARP) score, and to determine priority mitigation actions. This study uses integration methods. (HOR), and Analytic Network Process (ANP) with pareto diagrams and method-based ratings. The SCOR method is used to map supply chain activities and classify supply chain activities. Meanwhile, the HOR method is used in identifying risk events and risk agents, as well as assessments based on the assessment of the FMEA method. The output of the HOR method is the ARP score used for the priority of the risk agent. Pareto diagrams are used in the priority of risk agents that must be immediately addressed based on the ARP score. The ANP method is used to determine the priority of mitigation actions. Based on this study, researchers obtained 21 risk events and 30 risk agents with 17 risk agents including priority risk agents and 13 non-priority risk agents, and 10 mitigation measures.
Proposed supply chain risk mitigation strategy of chicken slaughter house PT X by house of risk method
Authors: Ulfah Maria , Lintang Trenggonowati Dyah , Zahra Yasmin Fadila
Published: October 2018

Slaughter House PT X is a company engaged in the production, trade, and distribution of chicken meat that having a role to provide the needs of raw material in a form of fresh chicken meat in the chicken meat processing industry. However, this company has the potential to experience a variety of supply chain risk that can disrupt the company’s business processes. The purposes of this study are to identify risk events that have been potentially occurred, identify priority risk agent based on Aggregate Risk Potential (ARP) value, and determine the priority sequence of a risk mitigation strategy in Slaughter House PT X. This study uses the Supply Chain Operation Reference (SCOR) to mapping the company’s supply chain activity. Thereafter House of Risk (HOR) method is used to identify, analyze, evaluate, and designing mitigation strategy to minimize potential occurrence of risk agent. The results of the study showed that there are 33 risk events and 32 risk agents identified. Then, based on the result of risk evaluation, there are 15 priority risk agents for mitigation action. There are 11 proposed mitigation strategies to be implemented in Slaughter House PT X.