资源类型

期刊论文 110

会议视频 4

年份

2023 10

2022 10

2021 14

2020 11

2019 3

2018 6

2017 7

2016 4

2015 7

2014 6

2013 2

2012 4

2011 2

2010 2

2009 3

2008 5

2007 3

2006 2

2005 1

2004 1

展开 ︾

关键词

碳中和 3

混沌序列 2

运动补偿 2

3D打印 1

CAESAR竞赛；认证加密算法；分组密码；序列密码；哈希函数；安全性评估 1

CFD 1

CO2 EOR 1

CO2净排放量 1

CO2封存 1

Casimir力 1

GOCE 1

GRACE 1

H∞控制；零和动态博弈；强化学习；自适应动态规划；极小极大Q-学习；策略迭代 1

SARS-CoV-2 1

Windows'95 1

YAG激光淬火 1

“1123”生态环保排放限值 1

“四性” 1

三峡电站 1

展开 ︾

检索范围：

排序： 展示方式：

A block zero-padding method based on DCFT for L1 parameter estimations in weak signal and high dynamic

Chao WU,Lu-ping XU,Hua ZHANG,Wen-bo ZHAO

《信息与电子工程前沿（英文）》 2015年 第16卷 第9期   页码 796-804 doi: 10.1631/FITEE.1500058

摘要： Weak L1 signal acquisition in a high dynamic environment primarily faces a challenge: the integration peak is negatively influenced by the possible bit sign reversal every 20 ms and the frequency error. The block accumulating semi-coherent integration of correlations (BASIC) is a state-of-the-art method, but calculating the inter-block conjugate products restricts BASIC in a low signal-to-noise ratio (SNR) acquisition. We propose a block zero-padding method based on a discrete chirp-Fourier transform (DCFT) for parameter estimations in weak signal and high dynamic environments. Compared with the conventional receiver architecture that uses closed-loop acquisition and tracking, it is more suitable for open-loop acquisition. The proposed method combines DCFT and block zero-padding. In this way, the post-correlation signal is coherently post-integrated with the bit sequence stripped off, and the high dynamic parameters are precisely estimated using the threshold set based on a false alarm probability. In addition, the detection performance of the proposed method is analyzed. Simulation results show that compared with the BASIC method, the proposed method can precisely detect the high dynamic parameters in lower SNR when the length of the received signal is fixed.

关键词： Threshold detection     Discrete chirp-Fourier transform     Block zero-padding     High dynamic     Weak L1 signal acquisition    

HTML PDF 收藏

Remediation of arsenic contaminated soil by sulfidated zero-valent iron

《环境科学与工程前沿（英文）》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1377-z

摘要：

• Sulfidation significantly enhanced As(V) immobilization in soil by zerovalent iron.

关键词： Soil     As(V)     Sulfidation     Zero-valent iron     Magnetic separation    

HTML PDF 收藏

Laser ablation of block copolymers with hydrogen-bonded azobenzene derivatives

Jintang Huang, Youju Huang, Si Wu

《化学科学与工程前沿（英文）》 2018年 第12卷 第3期   页码 450-456 doi: 10.1007/s11705-018-1735-6

摘要：

Supramolecular assemblies (PS-b-P4VP(AzoR)) are fabricated by hydrogen-bonding azobenzene derivatives (AzoR) to poly(4-vinyl pyridine) blocks of polystyrene-block-poly(4-vinyl pyridine) (PS-b-P4VP). PS-b-P4VP(AzoR) forms phase separated nanostructures with a period of ~75–105 nm. A second length scale structure with a period of 2 µm is fabricated on phase separated PS-b-P4VP(AzoR) by laser interference ablation. Both the concentration and the substituent of AzoR in PS-b-P4VP(AzoR) affect the laser ablation process. The laser ablation threshold of PS-b-P4VP(AzoR) decreases as the concentration of AzoR increases. In PS-b-P4VP(AzoR) with different substituents (R= CN, H, and CH3), ablation thresholds follow the trend: PS-b-P4VP(AzoCN)<PS-b-P4VP(AzoCH3)<PS-b-P4VP(AzoH). This result indicates that the electron donor group (CH3) and the electron acceptor group (CN) can lower the ablation threshold of PS-b-P4VP(AzoR).

关键词： laser ablation     block copolymers     hydrogen-bond     azobenzene derivatives     supramolecular assembly    

HTML PDF 收藏

Ductility improvement of GFRP-RC beams using precast confined concrete block in compression zone

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0968-8

摘要： Fiber-reinforced polymers (FRPs) have received considerable research attention because of their high strength, corrosion resistance, and low weight. However, owing to the lack of ductility in this material and the quasi-brittle behavior of concrete, FRP-reinforced concrete (FRP-RC) beams, even with flexural failure, do not fail in a ductile manner. Because the limited deformation capacity of FRP-RC beams depends on the ductility of their compression zones, the present study proposes using a precast confined concrete block (PCCB) in the compression zone to improve the ductility of the beams. A control beam and four beams with different PCCBs were cast and tested under four-point bending conditions. The control beam failed due to shear, and the PCCBs exhibited different confinements and perforations. The goal was to find an appropriate PCCB for use in the compression zone of the beams, which not only improved the ductility but also changed the failure mode of the beams from shear to flexural. Among the employed blocks, a ductile PCCB with low equivalent compressive strength increased the ductility ratio of the beam to twice that of the control beam. The beam failed in pure flexure with considerable deformation capacity and without significant stiffness reduction.

关键词： ductility     four-point bending test     glass fiber-reinforced polymer     precast confined concrete block    

HTML PDF 收藏

基于低复杂度最大似然的STBC-MIMO系统高效调制识别方法 Article

Maqsood H. SHAH, Xiao-yu DANG

《信息与电子工程前沿（英文）》 2020年 第21卷 第3期   页码 465-475 doi: 10.1631/FITEE.1800306

摘要： 针对正交空时块编码的多输入多输出系统（STBC-MIMO），提出一种基于低复杂度似然比的自动调制识别方法。使用迫零均衡技术修正平均似然比检验函数（ALRT）。与目前MIMO系统调制识别中使用的ALRT相比，本文提出的检验函数具有较低计算复杂度。在接收机具有非理想信道状态信息的条件下，对提出的方法在盲信道场景中进行分析。同时对不同天线数目的场景进行性能分析，利用Alamouti-STBC系统（2×2与2×1）和空时发射分集（4×4）的不同发射和接收天线配置验证本文所提方法，其中一些常用的调制方式被用作调制测试池。以正确识别率为指标，采用蒙特卡罗仿真法评价本文方法。仿真结果表明，该方法在低信噪比下有较好分类精度，在信道状态信息估计误差方差大的情况下有较好稳健性。

关键词： 多输入多输出；空时块编码；最大似然；自动调制识别；迫零均衡    

HTML PDF 收藏

Effects of different types of biochar on the properties and reactivity of nano zero-valent iron in soil

《环境科学与工程前沿（英文）》 2021年 第15卷 第5期 doi: 10.1007/s11783-021-1388-4

摘要：

• Biochar enhanced the mobility and stability of zero-valent iron nanoparticles.

关键词： Nano zero-valent iron     Biochar     BDE209     Transport     Soil    

HTML PDF 收藏

Degradation of chlorinated phenols by nanoscale zero-valent iron

CHENG Rong, WANG Jianlong, ZHANG Weixian

《环境科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 103-108 doi: 10.1007/s11783-008-0009-9

摘要： Chlorophenols (CPs), as important contaminants in groundwater, are toxic and difficult to biodegrade. Recently nanoscale zero-valent iron received a great deal of attention because of its excellent performance in treating recalcitrant compounds. In this study, nanoscale zero-valent iron particles were prepared using chemical reduction, and the reductive transformations of three kinds of chlorinated phenols (2-CP, 3-CP, and 4-CP) by nanoscale zero-valent iron under different conditions were investigated. The transformation process of the CPs was shown to be dechlorination first, then cleavage of the benzene ring. The removal efficiency of the CPs varied as follows: 2-CP > 3-CP > 4-CP. The reactivity of CPs was associated with their energy of lowest unoccupied molecular orbit (). With the increase in initial concentrations of CPs, removal efficiency decreased a little. But the quantities of CPs reduced increased evidently. Temperature had influence on not only the removal efficiency, but also the transformation pathway. At higher temperatures, dechlorination occurred prior to benzene ring cleavage. At lower temperatures, however, the oxidation product was formed more easily.
HTML PDF 收藏

Study on the Path of “Near-zero Emission” Coal-based Clean Energy Ecosystem Development

Zhang Yu-zhuo

《工程管理前沿（英文）》 2014年 第1卷 第1期   页码 37-41 doi: 10.15302/J-FEM-2014007

摘要： Developing a "near-zero emission" coal-based clean energy ecosystem bears great significance for the sustainable development of clean energy in China and the world at large. This article delves into the development strategy, implementation pathways and key priorities of China's "near-zero emission" coal-based clean energy ecosystem, and in turn proposes specific measures to underpin the development and implementation of such system.

关键词： near-zero emission     clean energy ecosystem     study on the path    

HTML PDF 收藏

Preparation of polysulfone-based block copolymer ultrafiltration membranes by selective swelling and

《化学科学与工程前沿（英文）》 2022年 第16卷 第5期   页码 745-754 doi: 10.1007/s11705-021-2038-x

摘要： Selective swelling of block copolymers of polysulfone-b-poly(ethylene glycol) is an emerging strategy to prepare new types of polysulfone ultrafiltration membranes. Herein, we prepared nanoporous polysulfone-b-poly(ethylene glycol) ultrafiltration membranes by selective swelling and further promoted their porosity and ultrafiltration performances by using CaCO3 nanoparticles as the sacrificial nanofillers. Different contents of CaCO3 nanoparticles were doped into the solution of polysulfone-b-poly(ethylene glycol), and thus obtained suspensions were used to prepare both self-supported and bi-layered composite structures. Selective swelling was performed on the obtained block copolymer structures in the solvent pair of ethanol/acetone, producing nanoporous membranes with poly(ethylene glycol) lined along pore walls. The CaCO3 nanoparticles dispersed in polysulfone-b-poly(ethylene glycol) were subsequently etched away by hydrochloric acid and the spaces initially occupied by CaCO3 provided extra pores to the block copolymer layers. The porosity of the membranes was increased with increasing CaCO3 content up to 41%, but further increase in the CaCO3 content led to partial collapse of the membrane. The sacrificial CaCO3 particles provided extra pores and enhanced the connectivity between adjacent pores. Consequently, the membranes prepared under optimized conditions exhibited up to 80% increase in water permeance with slight decrease in rejection compared to neat membranes without the use of sacrificial CaCO3 particles.

关键词： block copolymers     selective swelling     ultrafiltration     CaCO3 nanoparticles     sacrificial nanofillers    

HTML PDF 收藏

Thermoresponsive block copolymer supported Pt nanocatalysts for base-free aerobic oxidation of 5-hydroxymethyl

《化学科学与工程前沿（英文）》 2021年 第15卷 第6期   页码 1514-1523 doi: 10.1007/s11705-021-2092-4

摘要： A base-free catalytic system for the aerobic oxidation of 5-hydroxymethyl-2-furfural was exploited by using Pt nanoparticles immobilized onto a thermoresponsive poly(acrylamide-co-acrylonitrile)-b-poly(N-vinylimidazole) block copolymer, with an upper critical solution temperature of about 45 °C. The Pt nanocatalysts were well-dispersed and highly active for the base-free oxidation of 5-hydroxymethyl-2-furfural by molecular oxygen in water, affording high yields of 2,5-furandicarboxylic acid (up to>99.9%). The imidazole groups in the block copolymer were conducive to the improvement of catalytic performance. Moreover, the catalysts could be easily separated and recovered based on their thermosensitivity by cooling the reaction system below the upper critical solution temperature. Good stability and reusability were observed over these copolymer-immobilized catalysts with no obvious decrease in catalytic activity in the five consecutive cycles.

关键词： aerobic oxidation     base-free     5-hydroxymethyl-2-furfural     Pt nanoparticle     thermoresponsive block copolymer    

HTML PDF 收藏

Nanoscale zero-valent iron supported on biochar for the highly efficient removal of nitrobenzene

Gaoling Wei, Jinhua Zhang, Jinqiu Luo, Huajian Xue, Deyin Huang, Zhiyang Cheng, Xinbai Jiang

《环境科学与工程前沿（英文）》 2019年 第13卷 第4期 doi: 10.1007/s11783-019-1142-3

摘要：

• Biochar supported nanoscale zero-valent iron composite (nZVI/BC) was synthesized.

• nZVI/BC quickly and efficiently removed nitrobenzene (NB) in solution.

• NB removal by nZVI/BC involves simultaneous adsorption and reduction mechanism.

• nZVI/BC exhibited better catalytic activity, stability and durability than nZVI.

关键词： Biochar     Nanoscale zero-valent iron     Nitrobenzene     Reduction     Adsorption     Synergistic effec    

HTML PDF 收藏

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in

Yang Zhou, Phillip Choi

《化学科学与工程前沿（英文）》 2017年 第11卷 第3期   页码 440-447 doi: 10.1007/s11705-017-1626-2

摘要： Isothermal-isobaric molecular dynamics simulation was used to study the diffusion mechanism of water in polyurethane- -poly( -isopropyl acrylamide) (PU- -PNIPAm) with a hydrophobic PU/hydrophilic PNIPAm mass ratio of 1.4 to 1 at 298 K and 450 K. Here, the experimental glass transition temperature ( ) of PU is 243 K while that of PNIPAm is 383 K. Different amounts of water up to 15 wt-% were added to PU- -PNIPAm. We were able to reproduce the specific volumes and glass transition temperatures (250 K and 390 K) of PU- -PNIPAm. The computed self-diffusion coefficient of water increased exponentially with increasing water concentration at both temperatures (i.e., following the free volume model of Fujita). It suggested that water diffusion in PU- -PNIPAm depends only on its fractional free volume despite the free volume inhomogeneity. It is noted that at 298 K, PU is rubbery while PNIPAm is glassy. Regardless of temperature, radial distribution functions showed that water formed clusters with sizes in the range of 0.2–0.4 nm in PU- -PNIPAm. At low water concentrations, more clusters were found in the PU domain but at high water concentrations, more in the PNIPAm domain. It is believed that water molecules diffuse as clusters rather than as individual molecules.

关键词： molecular dynamics simulation     amphiphilic block copolymer     free volume     water diffusivity     fujita model    

HTML PDF 收藏

Cation exchange resin supported nanoscale zero-valent iron for removal of phosphorus in rainwater runoff

XIE Bangmi,ZUO Jiane,GAN Lili,LIU Fenglin,WANG Kaijun

《环境科学与工程前沿（英文）》 2014年 第8卷 第3期   页码 463-470 doi: 10.1007/s11783-013-0575-3

摘要： Self-made cation exchange resin supported nanoscale zero-valent iron (R-nZVI) was used to remove phosphorus in rainwater runoff. 80% of phosphorus in rainwater runoff from grassland was removed with an initial concentration of 0.72 mg·L phosphorus when the dosage of R-nZVI is 8 g per liter rainwater, while only 26% of phosphorus was removed when using cation exchange resin without supported nanoscale zero-valent iron under the same condition. The adsorption capacity of R-nZVI increased up to 185 times of that of the cation exchange resin at a saturated equilibrium phosphorous concentration of 0.42 mg·L . Various techniques were implemented to characterize the R-nZVI and explore the mechanism of its removal of phosphate. Scanning electron microscopy (SEM) indicated that new crystal had been formed on the surface of R-nZVI. The result from inductive coupled plasma (ICP) indicated that 2.1% of nZVI was loaded on the support material. The specific surface area was increased after the load of nanoscale zero-valent iron (nZVI), according to the measurement of BET-N method. The result of specific surface area analysis also proved that phosphorus was removed mainly through chemical adsorption process. X-ray photoelectron spectroscopy (XPS) analysis showed that the new product obtained from chemical reaction between phosphate and iron was ferrous phosphate.

关键词： nanoscale zero-valent iron(R-nZVI)     cation exchange resin     rainwater runoff     phosphorus adsorption    

HTML PDF 收藏

A compound load simulator based on zero-torsion parallel mechanisms

Jingjun YU, Wei LI, Xu PEI, Shusheng BI, Guanghua ZONG

《机械工程前沿（英文）》 2012年 第7卷 第1期   页码 1-4 doi: 10.1007/s11465-012-0306-7

HTML PDF 收藏

Immobilization of nano-zero-valent irons by carboxylated cellulose nanocrystals for wastewater remediation

Bangxian Peng, Rusen Zhou, Ying Chen, Song Tu, Yingwu Yin, Liyi Ye

《化学科学与工程前沿（英文）》 2020年 第14卷 第6期   页码 1006-1017 doi: 10.1007/s11705-020-1924-y

摘要： Nano-zero-valent irons (nZVI) have shown great potential to function as universal and low-cost magnetic adsorbents. Yet, the rapid agglomeration and easy surface corrosion of nZVI in solution greatly hinders their overall applicability. Here, carboxylated cellulose nanocrystals (CCNC), widely available from renewable biomass resources, were prepared and applied for the immobilization of nZVI. In doing so, carboxylated cellulose nanocrystals supporting nano-zero-valent irons (CCNC-nZVI) were obtained via an growth method. The CCNC-nZVI were characterized and then evaluated for their performances in wastewater treatment. The results obtained show that nZVI nanoparticles could attach to the carboxyl and hydroxyl groups of CCNC, and well disperse on the CCNC surface with a size of ~10 nm. With the CCNC acting as corrosion inhibitors improving the reaction activity of nZVI, CCNC-nZVI exhibited an improved dispersion stability and electron utilization efficacy. The Pb(II) adsorption capacity of CCNC-nZVI reached 509.3 mg·g (298.15 K, pH= 4.0), significantly higher than that of CCNC. The adsorption was a spontaneous exothermic process and could be perfectly fitted by the pseudo-second-order kinetics model. This study may provide a novel and green method for immobilizing magnetic nanomaterials by using biomass-based resources to develop effective bio-adsorbents for wastewater decontamination.

关键词： carboxylated cellulose nanocrystals     nano-zero-valent irons     magnetic bio-adsorbents     wastewater remediation    

HTML PDF 收藏

标题 作者 时间 类型 操作

A block zero-padding method based on DCFT for L1 parameter estimations in weak signal and high dynamic

Chao WU,Lu-ping XU,Hua ZHANG,Wen-bo ZHAO

期刊论文

Remediation of arsenic contaminated soil by sulfidated zero-valent iron

期刊论文

Laser ablation of block copolymers with hydrogen-bonded azobenzene derivatives

Jintang Huang, Youju Huang, Si Wu

期刊论文

Ductility improvement of GFRP-RC beams using precast confined concrete block in compression zone

期刊论文

基于低复杂度最大似然的STBC-MIMO系统高效调制识别方法

Maqsood H. SHAH, Xiao-yu DANG

期刊论文

Effects of different types of biochar on the properties and reactivity of nano zero-valent iron in soil

期刊论文

Degradation of chlorinated phenols by nanoscale zero-valent iron

CHENG Rong, WANG Jianlong, ZHANG Weixian

期刊论文

Study on the Path of “Near-zero Emission” Coal-based Clean Energy Ecosystem Development

Zhang Yu-zhuo

期刊论文

Preparation of polysulfone-based block copolymer ultrafiltration membranes by selective swelling and

期刊论文

Thermoresponsive block copolymer supported Pt nanocatalysts for base-free aerobic oxidation of 5-hydroxymethyl

期刊论文

Nanoscale zero-valent iron supported on biochar for the highly efficient removal of nitrobenzene

Gaoling Wei, Jinhua Zhang, Jinqiu Luo, Huajian Xue, Deyin Huang, Zhiyang Cheng, Xinbai Jiang

期刊论文

Molecular dynamics study of water diffusion in an amphiphilic block copolymer with large difference in

Yang Zhou, Phillip Choi

期刊论文

Cation exchange resin supported nanoscale zero-valent iron for removal of phosphorus in rainwater runoff

XIE Bangmi,ZUO Jiane,GAN Lili,LIU Fenglin,WANG Kaijun

期刊论文

A compound load simulator based on zero-torsion parallel mechanisms

Jingjun YU, Wei LI, Xu PEI, Shusheng BI, Guanghua ZONG

期刊论文

Immobilization of nano-zero-valent irons by carboxylated cellulose nanocrystals for wastewater remediation

Bangxian Peng, Rusen Zhou, Ying Chen, Song Tu, Yingwu Yin, Liyi Ye

期刊论文