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Size-controllable synthesis of monodispersed nitrogen-doped carbon nanospheres from polydopamine for

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1788-1800 doi: 10.1007/s11705-023-2326-8

摘要: Monodispersed nitrogen-doped carbon nanospheres with tunable particle size (100–230 nm) were synthesized via self-polymerization of biochemical dopamine in the presence of hexamethylenetetramine as a buffer and F127 as a size controlling agent. Hexamethylenetetramine can mildly release NH3, which in turn initiates the polymerization reaction of dopamine. The carbon nanospheres obtained exhibited a significant energy storage capability of 265 F·g–1 at 0.5 A·g–1 and high-rate performance of 82% in 6 mol·L–1 KOH (20 A·g–1), which could be attributed to the presence of abundant micro-mesoporous structure, doped nitrogen functional groups and the small particle size. Moreover, the fabricated symmetric supercapacitor device displayed a high stability of 94% after 5000 cycles, revealing the considerable potential of carbon nanospheres as electrode materials for energy storage.

关键词: carbon nanospheres     size-controlled     nitrogen-doped     high-rate     supercapacitors    

Controllable synthesis of a large TS-1 catalyst for clean epoxidation of a C=C double bond under mild

《化学科学与工程前沿(英文)》 2023年 第17卷 第6期   页码 772-783 doi: 10.1007/s11705-022-2280-x

摘要: Development of a titanium silicalite-1 (TS-1) catalyst with good crystallinity and a four-coordinate Ti framework is critical for efficient catalytic oxidation reaction under mild conditions. Herein, a size-controlled TS-1 zeolite (TS-1#0.1ACh (acetylcholine)) was synthesized via steam-assisted crystallization by introducing acetylcholine as a crystal growth modifier in the preparation process, and TS-1#0.1ACh was also employed in epoxidations of different substrates containing C=C double bonds. The crystalline sizes of the as-synthesized TS-1#0.1ACh catalysts were controlled with the acetylcholine content, and characterization results showed that the particle sizes of highly crystalline TS-1#0.1ACh zeolite reached 3.0 μm with a good Ti framework. Throughout the synthetic process, the growth rate of the crystals was accelerated by electrostatic interactions between the connected hydroxyl groups of the acetylcholine modifier and the negatively charged skeleton of the pre-zeolites. Furthermore, the TS-1#0.1ACh catalyst demonstrated maximum catalytic activity, good selectivity and high stability during epoxidation of allyl chloride. Importantly, the TS-1#0.1ACh catalyst was also highly versatile and effective with different unsaturated substrates. These findings may provide novel, easily separable and large TS-1 catalysts for efficient and clean industrial epoxidations of C=C double bonds.

关键词: size-controlled TS-1     crystal modifier     steam-assisted crystallization     epoxidation    

Controllable Fe/HCS catalysts in the Fischer-Tropsch synthesis: Effects of crystallization time

Yifei Wang, Shouying Huang, Xinsheng Teng, Hongyu Wang, Jian Wang, Qiao Zhao, Yue Wang, Xinbin Ma

《化学科学与工程前沿(英文)》 2020年 第14卷 第5期   页码 802-812 doi: 10.1007/s11705-019-1866-4

摘要: The Fischer–Tropsch synthesis (FTS) continues to be an attractive alternative for producing a broad range of fuels and chemicals through the conversion of syngas (H and CO), which can be derived from various sources, such as coal, natural gas, and biomass. Among iron carbides, Fe C, as an active phase, has barely been studied due to its thermodynamic instability. Here, we fabricated a series of Fe C embedded in hollow carbon sphere (HCS) catalysts. By varying the crystallization time, the shell thickness of the HCS was manipulated, which significantly influenced the catalytic performance in the FTS. To investigate the relationship between the geometric structure of the HCS and the physic-chemical properties of Fe species, transmission electron microscopy, X-ray diffraction, N physical adsorption, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction, Raman spectroscopy, and Mössbauer spectroscopy techniques were employed to characterize the catalysts before and after the reaction. Evidently, a suitable thickness of the carbon layer was beneficial for enhancing the catalytic activity in the FTS due to its high porosity, appropriate electronic environment, and relatively high Fe C content.

关键词: Fischer–Tropsch synthesis     Fe-based catalyst     Fe2C     hollow carbon sphere     crystallization time    

Shape/size controlling syntheses, properties and applications of two-dimensional noble metal nanocrystals

Baozhen An,Mingjie Li,Jialin Wang,Chaoxu Li

《化学科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 360-382 doi: 10.1007/s11705-016-1576-0

摘要: Two dimensional (2D) nanocrystals of noble metals (e.g., Au, Ag, Pt) often have unique structural and environmental properties which make them useful for applications in electronics, optics, sensors and biomedicines. In recent years, there has been a focus on discovering the fundamental mechanisms which govern the synthesis of the diverse geometries of these 2D metal nanocrystals (e.g., shapes, thickness, and lateral sizes). This has resulted in being able to better control the properties of these 2D structures for specific applications. In this review, a brief historical survey of the intrinsic anisotropic properties and quantum size effects of 2D noble metal nanocrystals is given and then a summary of synthetic approaches to control their shapes and sizes is presented. The unique properties and fascinating applications of these nanocrystals are also discussed.

关键词: two-dimension     noble metal     nanocrystal     surface plasmon     controllable synthesis    

Modeling and analysis of controllable output property of cantilever-beam inertial sensors based on magnetic

Guixiong LIU, Peiqiang ZHANG, Chen XU

《机械工程前沿(英文)》 2009年 第4卷 第2期   页码 129-133 doi: 10.1007/s11465-009-0035-8

摘要: Magnetic fluid is first introduced into the traditional cantilever-beam senor. Based on the property of the cantilever-beam and the novel controllable mag-viscosity of magnetic fluid, the output of cantilever-beam sensors is under control so that the controllable output of the sensors can be realized. The mathematical model of the sensors is established and analyzed. The dynamic control function and the following educational results, which include the two curves of the displacement ratio and phase function with the different damping ratio and frequency ratio, are obtained based on the model. The result shows that it is valid to realize the controllable output of the sensors by controlling the viscosity of the magnetic fluid, and finally the expanded measurement range can be realized.

关键词: sensors     magnetic fluid     property of mag-viscosity     controllable output    

A chemical etching route to controllable fabrication of TiO

Weixin ZHANG, Jie XING, Zeheng YANG, Mei KONG, Hongxu YAO

《化学科学与工程前沿(英文)》 2013年 第7卷 第2期   页码 192-201 doi: 10.1007/s11705-013-1319-4

摘要: The TiO hollow nanospheres with diameters of about 230 nm were prepared by a simple and controllable route based on hydrolysis of Ti(OBu) on the surfaces of the Cu O solid nanospheres followed by inward etching of the Cu O nanospheres. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The further post-heat treatment led to the high crystallization of the TiO hollow nanospheres. The photocatalytic performances of these samples were evaluated for the photodegradation of rhodamine B (RhB) under UV-light irradiation. The as-prepared TiO hollow nanospheres showed higher photocatalytic activity than the CuO and the CuO/TiO hollow nanospheres. Effects of temperature and time for post-heat treatment of TiO as well as initial RhB concentrations on the RhB photodegradation have also been studied. The results show that the TiO hollow nanospheres have the good reusability as photocatalysts and are promising in waste water treatment.

关键词: TiO2     hollow nanospheres     rhodamine B     photocatalytic activity    

二维可控细胞自动机伪随机序列发生方法研究

朱保平,马骞,刘凤玉

《中国工程科学》 2007年 第9卷 第6期   页码 43-47

摘要:

提出了一种新的细胞自动机———二维可控细胞自动机。根据二维可控细胞自动机的性质,提出了一 种具有梯型结构的二维可控细胞自动机的伪随机序列发生方法。计算机模拟表明,具有梯型结构的二维可控细 胞自动机伪随机序列发生器实现简单,产生的序列具有速度高、统计特性好等优点。新的细胞自动机在对称密 码学中有广泛地应用。

关键词: 细胞自动机     伪随机序列发生器     可控     密码学    

Frequency-controlable sine signal based on PWM and its implementation on FPGA

Lianzhen HUANG, Jiangang LI, Dongjun ZHANG

《机械工程前沿(英文)》 2012年 第7卷 第3期   页码 322-328 doi: 10.1007/s11465-012-0312-9

摘要:

A sine generation method that the different frequent sine signals can be generated by the different Pulse-Width Modulation (PWM) signals generated by Field-Programmable Gate Array (FPGA) through low-pass filter of fixed parameters was proposed. The method just takes a few FPGA resources and was proved feasible by the theory. The experiment results and theory analysis tally.

关键词: Pulse-Width Modulation (PWM)     Field-Programmable Gate Array (FPGA)     frequency controllable    

Automated synthesis of steady-state continuous processes using reinforcement learning

《化学科学与工程前沿(英文)》 2022年 第16卷 第2期   页码 288-302 doi: 10.1007/s11705-021-2055-9

摘要: Automated flowsheet synthesis is an important field in computer-aided process engineering. The present work demonstrates how reinforcement learning can be used for automated flowsheet synthesis without any heuristics or prior knowledge of conceptual design. The environment consists of a steady-state flowsheet simulator that contains all physical knowledge. An agent is trained to take discrete actions and sequentially build up flowsheets that solve a given process problem. A novel method named SynGameZero is developed to ensure good exploration schemes in the complex problem. Therein, flowsheet synthesis is modelled as a game of two competing players. The agent plays this game against itself during training and consists of an artificial neural network and a tree search for forward planning. The method is applied successfully to a reaction-distillation process in a quaternary system.

关键词: automated process synthesis     flowsheet synthesis     artificial intelligence     machine learning     reinforcement learning    

Effect of potassium carbonate on catalytic synthesis of calcium carbide at moderate temperature

Dejun SHI, Ke QIAO, Zifeng YAN

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 372-375 doi: 10.1007/s11705-010-0570-1

摘要: Calcium carbide was successfully synthesized by carbothermal reduction of lime with coke at 1973 K for 1.5 h. The effect of potassium carbonate as additive on the composition and morphology of the product was investigated using X-ray diffraction and scanning electron microscope. Addition of potassium carbonate increased the yield of calcium carbide. The sample in the presence of potassium carbonate generated acetylene gas of 168.3 L/kg, which was 10% higher than that in the absence of potassium carbonate. This result confirmed the catalytic effect of potassium carbonate on the synthesis of calcium carbide. A possible mechanism of the above effects was that the additive, which was melted at the reduction temperature, dissolved CaO and so promoted the contact between CaO and carbon, which was essential for the solid-solid reaction to form calcium carbide.

关键词: calcium carbide     synthesis     catalysis    

基于可控参数的前馈神经网络出水总氮预测模型研究 Article

赵子豪, 王子昊, 袁家洛, 马骏, 何哲灵, 徐一兰, 沈晓佳, 朱亮

《工程(英文)》 2021年 第7卷 第2期   页码 195-202 doi: 10.1016/j.eng.2020.07.027

摘要:

当前,出水总氮(TN)稳定达标是我国城镇污水处理厂面临的关键问题。本文基于我国城镇污水处理厂主流工艺——序批式活性污泥工艺(SBR),构建了一种基于可控参数的前馈神经网络(FFNN)出水总氮预测模型。与已有预测模型相比,本模型具备以下两个特点:①采用可控参数(表面气速与缺氧段时长)代替溶解氧作为模型主要输入参数,明显提高模型可用可控性;②采用算法优化的前馈神经网络构建模型,显著提高模型预测精准度。研究结果表明:量化共轭梯度法优化的FFNN模型预测精准,其拟合相关系数(R)明显高于其他相关模型;优化后的FFNN模型可根据进水与关键控制参数实现出水TN精准预测,有望实现城镇污水处理厂总氮稳定去除、系统节能降耗,助力国家“3060”碳目标实现。

关键词: 前馈神经网络(FFNN)     算法     可控参数     序批式活性污泥工艺     总氮    

Study on a green synthesis of

Aixin WANG, Yuanbin SHE, Jing FAN

《化学科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 219-221 doi: 10.1007/s11705-009-0058-z

摘要: A novel method for the synthesis of -oxo-bis[tetraarylporphyrinatoiron] ([TRPPFe] O) based on the reaction between tetraarylporphyrinironchloride (TRPPFeCl) and H O in toluene was investigated in this paper. Three kinds of [TRPPFe] O were synthesized by this novel synthetic method, and their structures were characterized by elemental analysis, IR spectra and UV-Vis spectroscopy.

关键词: μ-oxo-bis[tetraarylphenylporphinatoiron]     green synthesis     water    

Advantageous mechanochemical synthesis of copper(I) selenide semiconductor, characterization, and properties

《化学科学与工程前沿(英文)》 2022年 第16卷 第3期   页码 433-442 doi: 10.1007/s11705-021-2066-6

摘要: Copper(I) selenide-nanocrystalline semiconductor was synthesized via one-step mechanochemical synthesis after 5 min milling in a planetary ball mill. The kinetics of synthesis was followed by X-ray powder diffraction analysis and specific surface area measurements of milled 2Cu/Se mixtures. The X-ray diffraction confirmed the orthorhombic crystal structure of Cu2Se with the crystallite size ~25 nm. The surface chemical structure was studied by X-ray photoelectron spectroscopy, whereby the binding energy of the Cu 2p and Se 3d signals corresponded to Cu+ and Se2– oxidation states. Transmission electron microscopy revealed agglomerated nanocrystals and confirmed their orthorhombic structure, as well. The optical properties were studied utilizing ultraviolet-visible spectroscopy and photoluminescence spectroscopy. The direct bandgap energy 3.7 eV indicated a blue-shift phenomenon due to the quantum size effect. This type of Cu2Se synthesis can be easily adapted to production dimensions using an industrial vibratory mill. The advantages of mechanochemical synthesis represent the potential for inexpensive, environmentally-friendly, and waste-free manufacturing of Cu2Se.

关键词: Cu2Se     berzelianite     nanocrystalline semiconductor     mechanochemical synthesis     planetary ball mill    

Biomass to dimethyl ether by gasification/synthesis technology

Tiejun WANG, Yuping LI, Longlong MA, Chuangzhi WU

《能源前沿(英文)》 2011年 第5卷 第3期   页码 330-339 doi: 10.1007/s11708-010-0121-y

摘要: Technical and economic analysis was done for the biomass to dimethyl ether (DME) technology to promote the gasification/synthesis route for biofuel production and its application as a fossil fuel substitute. The technology of biomass gasification/synthesis has obvious advantages, including production flexibility, environmental friendliness, economic feasibility, and application versatility. Biomass gasification/synthesis technology integrates bio-DME synthesis, fertilizer production, electricity generation, and waste heat utilization to convert waste biomass residues to DME for use as liquid petroleum gas, transportation fuel substitute, and chemical intermediates, which has been proven to be one of the most effective and clean biomass utilization routes. The 1000 t/a-scale demonstration plant has a bio-DME production rate of 6 to 7 / , biomass gasification efficiency of≥82%, once-through CO conversion of ≥70%, DME selectivity (DME/DME+other organic products) of ≥90%, and a total system efficiency of ≥38%. The demonstration plant also has self-sufficient steam and electricity supply. The 10,000tons/a-scale bio-DME production cost with or without feedstock subsidy is estimated to be 1968 Yuan/t and 2868 Yuan/t, respectively in China. Because of the limitation in biomass feedstock collection cost, massive and disperse commercial plants with a capacity of 10000 t/a bio-DME are more suitable for rural areas.

关键词: technical and economic analysis     biomass     dimethyl ether     gasification/synthesis    

Multi-resolution texture synthesis from turntable image sequences

Xuedong WANG, Xiaojun WU, Xiaorong ZHANG

《机械工程前沿(英文)》 2012年 第7卷 第1期   页码 72-80 doi: 10.1007/s11465-012-0305-8

摘要:

Texture synthesis and texture mapping are important technologies for rendering realistic three-dimensional scene. It has been widely used in virtual reality, urban modeling, 3D animation, gaming and other areas. In this paper, we propose a fast method to construct high quality texture map for multi-resolution texture synthesis from turntable image sequences. Given a 3D mesh model, we first get the projection relationship between 3D mesh and image sequences. We then use image sequences to construct a texture triangle for each 3D triangle mesh and get a global rectangular texture map for the whole mesh. Another approach to construct a texture map is using Stretch-minimizing mesh parameterization. Finally, we map the texture to mesh model to verify the quality of these two methods. The high performance of this method has been demonstrated in many real object models.

关键词: texture synthesis     multi-resolution     texture map     texture mapping    

标题 作者 时间 类型 操作

Size-controllable synthesis of monodispersed nitrogen-doped carbon nanospheres from polydopamine for

期刊论文

Controllable synthesis of a large TS-1 catalyst for clean epoxidation of a C=C double bond under mild

期刊论文

Controllable Fe/HCS catalysts in the Fischer-Tropsch synthesis: Effects of crystallization time

Yifei Wang, Shouying Huang, Xinsheng Teng, Hongyu Wang, Jian Wang, Qiao Zhao, Yue Wang, Xinbin Ma

期刊论文

Shape/size controlling syntheses, properties and applications of two-dimensional noble metal nanocrystals

Baozhen An,Mingjie Li,Jialin Wang,Chaoxu Li

期刊论文

Modeling and analysis of controllable output property of cantilever-beam inertial sensors based on magnetic

Guixiong LIU, Peiqiang ZHANG, Chen XU

期刊论文

A chemical etching route to controllable fabrication of TiO

Weixin ZHANG, Jie XING, Zeheng YANG, Mei KONG, Hongxu YAO

期刊论文

二维可控细胞自动机伪随机序列发生方法研究

朱保平,马骞,刘凤玉

期刊论文

Frequency-controlable sine signal based on PWM and its implementation on FPGA

Lianzhen HUANG, Jiangang LI, Dongjun ZHANG

期刊论文

Automated synthesis of steady-state continuous processes using reinforcement learning

期刊论文

Effect of potassium carbonate on catalytic synthesis of calcium carbide at moderate temperature

Dejun SHI, Ke QIAO, Zifeng YAN

期刊论文

基于可控参数的前馈神经网络出水总氮预测模型研究

赵子豪, 王子昊, 袁家洛, 马骏, 何哲灵, 徐一兰, 沈晓佳, 朱亮

期刊论文

Study on a green synthesis of

Aixin WANG, Yuanbin SHE, Jing FAN

期刊论文

Advantageous mechanochemical synthesis of copper(I) selenide semiconductor, characterization, and properties

期刊论文

Biomass to dimethyl ether by gasification/synthesis technology

Tiejun WANG, Yuping LI, Longlong MA, Chuangzhi WU

期刊论文

Multi-resolution texture synthesis from turntable image sequences

Xuedong WANG, Xiaojun WU, Xiaorong ZHANG

期刊论文