Ordinal Optimization Theory Based Planning for Clustered Wind Farms Considering the Capacity Credit

Wang, Yi,Zhang, Ning,Kang, Chongqing,Xu, Qianyao,Li, Hui,Xiao, Jinyu,Wang, Zhidong,Shi, Rui,Wang, Shuai The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.5

Wind power planning aims to locate and size wind farms optimally. Traditionally, wind power planners tend to choose the wind farms with the richest wind resources to maximize the energy benefit. However, the capacity benefit of wind power should also be considered in large-scale clustered wind farm planning because the correlation among the wind farms exerts an obvious influence on the capacity benefit brought about by the combined wind power. This paper proposes a planning model considering both the energy and the capacity benefit of the wind farms. The capacity benefit is evaluated by the wind power capacity credit. The Ordinal Optimization (OO) Theory, capable of handling problems with non-analytical forms, is applied to address the model. To verify the feasibility and advantages of the model, the proposed model is compared with a widely used genetic algorithm (GA) via a modified IEEE RTS-79 system and the real world case of Ningxia, China. The results show that the diversity of the wind farm enhances the capacity credit of wind power.

A 0.03 mm2 delta-sigma modulator with cascaded-inverter amplifier

Wang, Zhidong,Duan, Quanzhen,Roh, Jeongjin Springer-Verlag 2014 Analog Integrated Circuits and Signal Processing Vol.81 No.2

Prolonged antimicrobial activity of silver core-carbon shell nanoparticles

Zengkai Wang,Tianke Wang,An Hua,Song Ma,Zhidong Zhang,Lei Liu 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.11

Ag nanoparticles present good antimicrobial activity but with a potential toxicity to the cell, which limits the application. To address this issue, in this work, carbon-encapsulated sliver nanocapsules (Ag@C nanocapsules) were prepared by evaporating pure Ag ingot with the modified arc-discharge technique, and the Ag@C nanocapsules were acidified with nitric acid subsequently to facilitate the silver ion to release. Finally, Ag@C nanocapsules displayed a good and sustained antimicrobial activity against E. coli as a model of Gram-negative bacteria, due to the long-term release of sliver ions from Ag@C nanocapsules. The results obtained in this work indicate that the Ag@C nanocapsules may be a suitable nanomaterial for the bactericidal application.

Ordinal Optimization Theory Based Planning for Clustered Wind Farms Considering the Capacity Credit

Yi Wang,Ning Zhang,Chongqing Kang,Qianyao Xu,Hui Li,Jinyu Xiao,Zhidong Wang,Rui Shi,Shuai Wang 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.5

Wind power planning aims to locate and size wind farms optimally. Traditionally, wind power planners tend to choose the wind farms with the richest wind resources to maximize the energy benefit. However, the capacity benefit of wind power should also be considered in large-scale clustered wind farm planning because the correlation among the wind farms exerts an obvious influence on the capacity benefit brought about by the combined wind power. This paper proposes a planning model considering both the energy and the capacity benefit of the wind farms. The capacity benefit is evaluated by the wind power capacity credit. The Ordinal Optimization (OO) Theory, capable of handling problems with non-analytical forms, is applied to address the model. To verify the feasibility and advantages of the model, the proposed model is compared with a widely used genetic algorithm (GA) via a modified IEEE RTS-79 system and the real world case of Ningxia, China. The results show that the diversity of the wind farm enhances the capacity credit of wind power.

Controlled synthesis of Co₂C nanochains using cobalt laurate as precursor: Structure, growth mechanism and magnetic properties

Zhang, Yajing,Zhu, Yuan,Wang, Kangjun,Li, Da,Wang, Dongping,Ding, Fu,Meng, Dan,Wang, Xiaolei,Choi, Chuljin,Zhang, Zhidong Elsevier 2018 Journal of magnetism and magnetic materials Vol.456 No.-

<P><B>Abstract</B></P> <P>Cobalt carbides (Co<SUB>2</SUB>C and Co<SUB>3</SUB>C) nanocomposites exhibit interesting hard magnetic property, controlled synthesis of individual phase facilitates to clarify the magnetism of each, but it is difficult to obtain the single phase. We present a new approach to address this issue via a polyol refluxing process, using cobalt laurate as the precursor. The single phase Co<SUB>2</SUB>C magnetic nanochains self-assembled by nanoparticles are synthesized. The precursor is the key factor for controlling the growth kinetics of the Co<SUB>2</SUB>C nanochains. Cobalt, instead of cobalt carbides, is produced if cobalt chloride, acetate and acetylacetonate replace cobalt laurate as the precursor, respectively. The evolution of the growth process has been studied. In the formation of Co<SUB>2</SUB>C, first fcc-Co produces, then it transforms into Co<SUB>2</SUB>C by carbon diffusion process, and the produced carbon first exists in disordered state and then a small amount of them transforms into graphite. Saturation magnetization (<I>Ms</I>) of Co<SUB>2</SUB>C nanochains obtained at 300 °C for 20, 60, and 180 min are 27.1, 18.9, and 10.9 emu g<SUP>−1</SUP>, respectively. The decrease of <I>Ms</I> caused by increasing carbon content, and the carbon content are much larger than the stoichiometric ratio value of Co<SUB>2</SUB>C (9.2 wt%). The Co<SUB>2</SUB>C nanochains have mesoporous pore of 3.8 nm and the specific surface area of 48.6 m<SUP>2</SUP> g<SUP>−1</SUP>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Co<SUB>2</SUB>C magnetic nanochains are synthesized using cobalt laurate as the precursor in TEG. </LI> <LI> The precursor of cobalt laurate is the key factor for controlling the growth kinetics of Co<SUB>2</SUB>C nanochains. </LI> <LI> Ms of Co<SUB>2</SUB>C nanochains obtained at 300 °C for 20, 60, and 180 min are 27.1, 18.9, and 10.9 emu g<SUP>−1</SUP>, respectively. </LI> <LI> The decrease of Ms is caused by increasing carbon content with increasing reaction time. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>We present a new approach to obtain single phase Co<SUB>2</SUB>C nanochains by using cobalt laurate as the precursor.</P> <P>[DISPLAY OMISSION]</P>

Distributed Filtering for Markovian Jump Systems With Packet Loss Compensation

Zhidong Zhou,Yuyan Wu,Jun Cheng,Yunliang Wang 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.7

In this article, the distributed-based filtering problem is studied for a type of Markov jump system subject to mode-dependent random packet losses. Packet dropout happens during the communication channel, which can be described via a random variable. In order to describe the nonhomogeneous Markov process, transition probabilities (TPs) on polytopic-structure-based are introduced. In view of packet loss, added by the single exponential smoothing (SES) technique, the packet loss compensation is provided to deal with the prediction value of the missing output. Besides, as for the physical limitations, it is quite difficult to ensure that all mode signals of the plant are available to filter. In the sequel, we establish a partially mode-dependent filter (PMDF). By using the Lyapunov theory, some sufficient conditions are obtained to guarantee the stochastically stable (SS) of the filtering error system (FES), and the filter parameters can be derived. Lastly, the validity of the presented results is tested through a numerical example.

Structural and Magnetic Properties of the Gas Atomized Mn-Al Alloy Powders

Xiaolei Wang,Junggoo Lee,Jooho Lee,Hwijun Kim,Chuljin Choi,Zhidong Zhang 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.4

Ferromagnetic Mn-Al powders were produced by a gas-atomization method followed by heating treatment. The gas-atomized powders were ε-phase, which is a high temperature phase in the Mn-Al system. The ε-τ phase transformation took place by subsequent heat treatment at temperatures from 500 to 700 °C. The gas-atomized powders with a smaller particle size formed the τ-phase faster and thus exhibited better magnetic properties. On the other hand, the annealing temperature and time similarly played important roles in determining the magnetic properties of the products. The Mn-Al powders of 25-38 μm annealed at 550 °C for 120 min exhibited a high coercivity of 3.2 kOe with a remanence of 38 emu/g.

Neodymium disilicate ceramic pigment synthesized by solid-state method with pre-grinding and mineralizer

Shanjun Ke,Yanmin Wang,Zhidong Pan,He-Ping Zeng 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.3

A ceramic pigment of neodymium disilicate (i.e., Nd2Si2O7) was synthesized via solid-state reaction with pre-grinding assistanceand a mineralizer. The effects of pre-grinding and mineralizer (i.e., lithium chloride, boric acid and calcium fluoride) on thephase, microstructure and coloring properties of ceramic pigment were investigated by differential thermal analysis, X-raydiffraction, scanning electron microscopy and reflectance spectra in the visible range from 400 nm to 700 nm, respectively. Theresults show that the reaction temperature of Nd2Si2O7 can be decreased by pre-grinding, and the temperature of forming soleNd2Si2O7 phase is further decreased by 200 oC when lithium chloride is used as a mineralizer. Boric acid as a mineralizer canlead to an uneven distribution of Nd and Si components. The sample synthesized with calcium fluoride as a mineralizer cannotobtain Nd2Si2O7 phase. Nd2Si2O7 can be synthesized effectively when lithium chloride is used as a mineralizer.

Brep2Seq: a dataset and hierarchical deep learning network for reconstruction and generation of computer-aided design models

Zhang Shu-Ming,Guan Zhidong,Jiang Hao,Ning Tao,Wang Xiao-Dong,Tan Pingan 한국CDE학회 2024 Journal of computational design and engineering Vol.11 No.1

Three-dimensional (3D) reconstruction is a significant research topic in the field of computer-aided design (CAD), which is used to recover editable CAD models from original shapes, including point clouds, voxels, meshes, and boundary representations (B-rep). Recently, there has been considerable research interest in deep model generation due to the increasing potential of deep learning methods. To address the challenges of 3D reconstruction and generation, we propose Brep2Seq, a novel deep neural network designed to transform the B-rep model into a sequence of editable parametrized feature-based modeling operations comprising principal primitives and detailed features. Brep2Seq employs an encoder-decoder architecture based on the transformer, leveraging geometry and topological information within B-rep models to extract the feature representation of the original 3D shape. Due to its hierarchical network architecture and training strategy, Brep2Seq achieved improved model reconstruction and controllable model generation by distinguishing between the primary shape and detailed features of CAD models. To train Brep2Seq, a large-scale dataset comprising 1 million CAD designs is established through an automatic geometry synthesis method. Extensive experiments on both DeepCAD and Fusion 360 datasets demonstrate the effectiveness of Brep2Seq, and show its applicability to simple mechanical components in real-world scenarios. We further apply Brep2Seq to various downstream applications, including point cloud reconstruction, model interpolation, shape constraint generation, and CAD feature recognition.

Preparation and thermodynamic equilibrium analysis of neodymium disilicate via sol-precipitation and sintering

Shanjun Ke,Yanmin Wang,Zhidong Pan,He-Ping Zeng 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.3

Neodymium disilicate powders were synthesized via a sol-precipitation method with different precipitants (i.e., ammonia,ammonium bicarbonate and urea) and subsequent sintering. The samples were characterized by X-ray diffraction. In addition,a theoretical relationship between neodymium ion concentrations in different precipitation equilibrium solutions was alsoinvestigated and analyzed based on thermodynamic equilibrium calculation. The results show that the precipitant type has animpact on the phase compositions of the precursors and the sintered products. In the synthesis, neodymium ions can becompletely precipitated as amorphous neodymium hydroxide with ammonia as a precipitate at pH 8~9. For ammoniumbicarbonate as a precipitate, the precursor type is related to both carbon concentration and pH value. The excessive hydroxideforms neodymium hydroxycarbonate in a heated urea solution. The possible formation mechanism of silicon sol in the presenceof different precipitants was discussed.