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在光纤激光器中利用Ti3C2 MXene材料产生矢量孤子和类噪声脉冲 Research

王帅1,李雷1,宋宇峰2,唐定远3,沈德元1,赵鹭明1,4

《信息与电子工程前沿（英文）》 2021年第22卷第3期页码 287-436 doi: 10.1631/FITEE.2000033

摘要：本文利用Ti3C2 MXene材料作为可饱和吸收体，搭建了铥钬共掺光纤激光器，观察到矢量孤子和类噪声脉冲的形成。其中，可饱和吸收体是通过将Ti3C2溶液滴在侧面抛光的D形光纤上自然挥发后制备而成。据我们所知，这是首次利用Ti3C2 MXene材料作为可饱和吸收体从光纤激光器中获得矢量孤子。

关键词：矢量孤子；类噪声脉冲；MXene；光纤激光器

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Dual cross-linked MXene/cellulose nanofiber/nickel alginate film with improved mechanical properties

《化学科学与工程前沿（英文）》 2023年第17卷第10期页码 1460-1469 doi: 10.1007/s11705-023-2335-7

摘要： Electromagnetic interference pollution has raised urgent demand for the development of electromagnetic interference shielding materials. Transition metal carbides (MXenes) with excellent conductivity have shown great potential in electromagnetic interference (EMI) shielding materials, while the poor mechanical strength, flexibility, and structural stability greatly limit their further applications. Here, cellulose nanofibers and sodium alginate are incorporated with MXene nanosheets as flexible matrices to construct strong and flexible mussel-like layered MXene/Cellulose nanofiber/Sodium Alginate composite films, and nickel ions are further introduced to induce metal coordination crosslinking of alginate units. Benefited from the dual-crosslinked network structure of hydrogen bonding and metal coordination, the tensile strength, Young’s modulus, and toughness of the MXene/cellulose nanofiber/nickel alginate composite film are significantly increased. After subsequent reduction by ascorbic acid, excess nickel ions are reduced to nickel nanoparticles and uniformly dispersed within the highly conductive composite film, which further improved its hysteresis loss effect toward the incident electromagnetic waves. Consequently, the MXene/cellulose nanofiber/nickel alginate-Ni composite film presents a considerably enhanced electromagnetic interference shielding effectiveness (47.17 dB) at a very low thickness of 29 μm. This study proposes a feasible dual-crosslinking and subsequent reduction strategy to synergistically enhance the mechanical properties and electromagnetic interference shielding performance of MXene-based composite materials.

关键词： Ti₃C₂T_x MXene double crosslinking mechanical properties EMI shielding performance

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Synthesis of Chl@Ti

Wenxin Xu, Xin Zhao, Jiali Tang, Chao Zhang, Yu Gao, Shin-ichi Sasaki, Hitoshi Tamiaki, Aijun Li, Xiao-Feng Wang

《化学科学与工程前沿（英文）》 2021年第15卷第3期页码 709-716 doi: 10.1007/s11705-020-1984-z

摘要： Two-dimensional (2D) titanium carbide MXene Ti C has attracted significant research interest in energy storage applications. In this study, we prepared Chl@Ti C composites by simply mixing a chlorophyll derivative (e.g., zinc methyl 3-devinyl-3-hydroxymethyl- pyropheophorbide (Chl)) and Ti C in tetrahydrofuran, where the Chl molecules were aggregated among the multi-layered Ti C MXene or on its surface, increasing the interlayer space of Ti C . The as-prepared Chl@Ti C was employed as the anode material in the lithium-ion battery (LIB) with lithium metal as the cathode. The resulting LIB exhibited a higher reversible capacity and longer cycle performance than those of LIB based on pure Ti C , and its specific discharge capacity continuously increased along with the increasing number of cycles, which can be attributed to the gradual activation of Chl@Ti C accompanied by the electrochemical reactions. The discharge capacity of 1 wt-% Chl@Ti C was recorded to be 325 mA·h·g at the current density of 50 mA·g with a Coulombic efficiency of 56% and a reversible discharge capacity of 173 mA·h·g at the current density of 500 mA·g after 800 cycles. This work provides a novel strategy for improving the energy storage performance of 2D MXene materials by expanding the layer distance with organic dye aggregates.

关键词： zinc chlorin aggregate Ti₃C₂ MXene anode material lithium storage

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一种使用交互分析武器系统对作战场景基于过程建模的方法 Research

Dongsu JEONG, Dohyun KIM, Yoonho SEO

《信息与电子工程前沿（英文）》 2021年第22卷第3期页码 287-436 doi: 10.1631/FITEE.1900649

摘要：该方法包括以下3个步骤：（1）通过将武器和武器功能转换为相应的组件来构建虚拟模型；（2）依据战斗情景生成战斗过程，该战斗过程是使用推理规则从被研究的武器之间的相互关系中得出的；（3）通过将战斗过程与虚拟模型相结合

关键词：武器系统；基于过程的建模（PBM）；作战场景；交互分析；元模型；Petri网

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配位不饱和Au-O-Ti³⁺活性位点的构建及其在低温丙烯气相环氧化反应中强化氢气效率的研究 Article

宋钊宁, 闫昊, 袁俊聪, 马宏飞, 曹建琳, 王永祥, 王强, 彭冲, 邓风, 冯翔, 陈德, 杨朝合, 胡永康

《工程（英文）》 2023年第25卷第6期页码 144-156 doi: 10.1016/j.eng.2023.01.008

摘要：

自1998年以来，人们广泛认为Au/Ti基催化剂的Au-O-Ti⁴⁺位点是在相对高温条件下丙烯气相环氧化反应的活性位点，但该类催化剂的H₂有效利用率普遍较低值得注意的是，该活性位点主导反应时，最佳温度可从200 °C显著降低至138 °C，并使催化剂保持前所未有的43.6%的H₂有效利用率、90.7%的环氧丙烷（PO）本工作通过调整处理后S-1晶种中Si-OH和Bu₃NH⁺的量，定量构建了Au-O-Ti³⁺活性位点。并且利用原位紫外-可见光谱（operando UV-vis）技术研究了Ti-OOH反应中间体的动态演化过程，结果表明，在Au-O-Ti³⁺活性位点上的Ti-OOH的生成速率比在Au-O-TiTi³⁺位点促进了Au和Ti³⁺之间的电子转移，从而增强了催化剂对O₂的吸附能力，有效促进H₂O₂

关键词：丙烯环氧化 H₂有效利用率 Au/Ti双功能催化剂配位不饱和Ti位点密度泛函理论

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Anodic oxidation of azo dye C.I. Acid Red 73 by the yttrium-doped Ti/SnO

Li XU, Zhi GUO, Lishun DU

《化学科学与工程前沿（英文）》 2013年第7卷第3期页码 338-346 doi: 10.1007/s11705-013-1335-4

摘要： This work was conducted to study the ability of anodic oxidation of azo dye C.I. Acid Red 73 (AR73) using the yttrium-doped Ti/SnO -Sb electrodes. The effects of Sb doping level, yttrium doping level, thermal decomposition temperature and cycle times of dip-coating thermal decomposition on the properties of the electrodes were investigated. The results showed that the excellent electrochemical activity of Ti/SnO -Sb-Y electrode can be achieved at a 7∶1 molar ratio of Sn∶Sb and thermal decomposition temperature of 550°C. Moreover when the cycle times of dip-coating and thermal decomposition were up to 10 times, the performance of the electrode tends to be stable. The Ti/SnO -Sb electrodes doped with yttrium (0.5 mol-%) showed the most excellent electrochemical activity. In addition, the influences of operating variables, including current density, initial pH, dye concentration and support electrolyte, on the colour removal, chemical oxygen demand (COD) removal and current efficiency were also investigated. Our results confirmed that the current efficiency increased with the concentrations of dye and sodium chloride. Moreover, increasing the current density and the initial pH would reduce the current efficiency.

关键词： SnO₂-Sb yttrium doping anodic oxidation azo dyes

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Recent progress in the design and fabrication of MXene-based membranes

Kai Qu, Kang Huang, Zhi Xu

《化学科学与工程前沿（英文）》 2021年第15卷第4期页码 820-836 doi: 10.1007/s11705-020-1997-7

摘要： Two-dimensional membranes have attracted significant attention due to their superior characteristics, and their ability to boost both flux and selectivity have led to their reputation as potential next-generation separation membranes. Among them, emerging MXene-based membranes play significant roles in the competitive membrane-separation field. In this mini-review, we systematically discuss the assembly and separation mechanisms of these membranes. Moreover, we highlight strategies based on the crosslinking of MXene nanosheets and the construction of additional nanochannels that further enhance the permeabilities and anti-swelling properties of MXene-based membranes and meet the requirements of practical applications, such as gas-molecule sieving, ion sieving, and other small-molecule sieving. MXene nanosheets can also be used as additives that introduce specific functionalities into hybrid membranes. In addition, extended applications that use MXenes as scaffolds are also discussed.

关键词： MXene 2D materials membranes separation

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Effective regeneration of thermally deactivated commercial V-W-Ti catalysts

Xuesong SHANG, Jianrong LI, Xiaowei YU, Jinsheng CHEN, Chi HE

《化学科学与工程前沿（英文）》 2012年第6卷第1期页码 38-46 doi: 10.1007/s11705-011-1167-z

摘要： An effective method for the regeneration of thermally deactivated commercial monolith SCR catalysts was investigated. Two types of regenerated solutions, namely NH Cl (1 mol/L) and dilute H SO (0.5 mol/L), were employed to treat the used catalyst. The effects of temperature and the regeneration process on the structural and textural properties of the catalysts were determined by X-ray diffraction, scanning electron microscopy, N adsorption/desorption, elemental analysis and Fourier transform infrared spectroscopy. The results suggest that the anatase phase of the used catalyst is maintained after exposure to high temperatures. Some of the catalytic activity was restored after regeneration. The catalyst regenerated by aqueous NH Cl had a higher activity than that of the catalyst treated by dilute H SO . The main reason is that the NH generated from the decomposition of NH Cl at high temperatures can be adsorbed onto the catalyst which promotes the reaction. The aggregated V O were partially re-dispersed during the regeneration process, and the intrinsic oxidation of ammonia with high concentrations of O is a factor that suppresses the catalytic activity.

关键词： V₂O₅-WO₃/TiO₂ catalysts thermal deactivation regeneration NH₄Cl dilute H₂SO₄ solution

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Facile controlled synthesis of hierarchically structured mesoporous Li4Ti5O12/C/rGO composites as high-performance

Cehuang FU, Shuiyun SHEN, Ruofei WU, Xiaohui YAN, Guofeng XIA, Junliang ZHANG

《能源前沿（英文）》 2022年第16卷第4期页码 607-612 doi: 10.1007/s11708-021-0798-0

摘要： In this paper, a facile strategy is proposed to controllably synthesize mesoporous Li₄Ti₅O₁₂/C nanocomposite embedded in graphene matrix as lithium-ion battery anode via the co-assembly of Li₄Ti₅O₁₂ (LTO) precursor, GO, and phenolic resin. The obtained composites, which consists of a LTO core, a phenolic-resin-based carbon shell, and a porous frame constructed by rGO, can be denoted as LTO/C/rGO and presents a hierarchical structure. Owing to the advantages of the hierarchical structure, including a high surface area and a high electric conductivity, the mesoporous LTO/C/rGO composite exhibits a greatly improved rate capability as the anode material in contrast to the conventional LTO electrode.

关键词： Li₄Ti₅O₁₂ phenolic-resin-based carbon mesoporous composite graphene

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Nickel(II) ion-intercalated MXene membranes for enhanced H₂/CO₂ separation

Yiyi Fan, Jinyong Li, Saidi Wang, Xiuxia Meng, Yun Jin, Naitao Yang, Bo Meng, Jiaquan Li, Shaomin Liu

《化学科学与工程前沿（英文）》 2021年第15卷第4期页码 882-891 doi: 10.1007/s11705-020-1990-1

摘要： Hydrogen fuel has been embraced as a potential long-term solution to the growing demand for clean energy. A membrane-assisted separation is promising in producing high-purity H . Molecular sieving membranes (MSMs) are endowed with high gas selectivity and permeability because their well-defined micropores can facilitate molecular exclusion, diffusion, and adsorption. In this work, MXene nanosheets intercalated with Ni were assembled to form an MSM supported on Al O hollow fiber via a vacuum-assisted filtration and drying process. The prepared membranes showed excellent H /CO mixture separation performance at room temperature. Separation factor reached 615 with a hydrogen permeance of 8.35 × 10 mol·m ·s ·Pa . Compared with the original Ti C T /Al O hollow fiber membranes, the permeation of hydrogen through the Ni -Ti C T /Al O membrane was considerably increased, stemming from the strong interaction between the negatively charged MXene nanosheets and Ni . The interlayer spacing of MSMs was tuned by Ni . During 200-hour testing, the resultant membrane maintained an excellent gas separation without any substantial performance decline. Our results indicate that the Ni tailored Ti C T /Al O hollow fiber membranes can inspire promising industrial applications.

关键词： MXene H₂/CO₂ separation nickel ions hollow fiber

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Toughening of vinyl ester resins by two-dimensional MXene nanosheets

《化学科学与工程前沿（英文）》页码 1651-1658 doi: 10.1007/s11705-022-2208-5

摘要： Two-dimensional nanosheets are highly effective tougheners for vinyl ester resins. The toughening effect is related to the high specific surface area and unique two-dimensional planar structure of the nanosheets. In this study, a coupling agent γ-(2,3-epoxypropoxy) propytrimethoxysilane (Kh-560) was used to modify MXene nanosheets (M-MXene) for use in toughening vinyl ester resin. The mechanical properties, including the tensile strength, flexural strength, Young’s modulus and elongation, of neat vinyl ester resin and vinyl ester resin modified with MXene and M-MXene were investigated. The results showed that modification significantly improved the mechanical properties of the vinyl ester resin. The tensile and flexural strengths of the MXene-nanosheet-modified vinyl ester resin were 27.20% and 25.32% higher, respectively, than those of the neat vinyl ester resin. The coupling agent improved the interfacial compatibility between the MXene nanosheets and vinyl ester resin, which resulted in the tensile and flexural strengths of the M-MXene-nanosheet-modified vinyl ester resin being 52.57% and 54.60% higher, respectively, than those of the neat vinyl ester resin for a loading quantity of nanosheets of only 0.04 wt %, which is economically viable. The main mechanisms by which the nanosheets toughen the resin are crack deflection and crack pinning.

关键词： MXene nanosheets 2D material vinyl ester resin modification coupling agent

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Durability of plasma-sprayed Cr3C2-NiCr coatings under rolling contact conditions

Xiancheng ZHANG, Fuzhen XUAN, Shantung TU, Binshi XU, Yixiong WU

《机械工程前沿（英文）》 2011年第6卷第1期页码 118-135 doi: 10.1007/s11465-011-0127-0

摘要：

The aim of this paper was to address the rolling contact fatigue (RCF) failure mechanisms of plasma-sprayed Cr3C2-NiCr coatings under different tribological conditions of contact stress. Weibull distribution plots of fatigue lives of the coated specimens at different contact stresses were obtained. The failure modes of coatings were identified on the basis of wore surface observations of the failed coatings. Results showed that the RCF failure modes can be classified into four main categories, i.e., surface abrasion, spalling, cohesive delamination, and interfacial delamination. The probabilities of the surface abrasion and spalling type failures were relatively high at low contact stress. When the coatings were subjected to abrasion and spalling type failures, the failure of the coating was depended on the microstrcture of the coating. The stress concentration near the micro-defects in the coating may be the may reason for the formation of spall. The coatings were prone to fail in delamination under higher contact stresses. However, the delamination of coating may be related to distribution of shear stress amplitude within coating. The location of maximum shear stress amplitude can be used as a key parameter to predict the initiation of subsurface cracks within coating in rolling contact.

关键词： rolling contact fatigue coating Weibull distribution failure mode mechanism

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Effect of noble metal nanoparticle size on C–N bond cleavage performance in hydrodenitrogenation: a study

《化学科学与工程前沿（英文）》 2023年第17卷第12期页码 1986-2000 doi: 10.1007/s11705-023-2337-5

摘要： Breakage of the C–N bond is a structure sensitive process, and the catalyst size significantly affects its activity. On the active metal nanoparticle scale, the role of catalyst size in C–N bond cleavage has not been clearly elucidated. So, Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature, and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o-propylaniline with different C–N bond hybridization patterns as reactants. Results showed a 13 times higher reaction rate for sp³-hybridized C–N bond cleavage than sp²-hybridized C–N bond cleavage, while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size increased. Different concentrations of terrace, step, and corner sites were found in different sizes of Ru nanoparticles. The relationship between catalytic site variation and C–N bond cleavage activity was further investigated by calculating the turnover frequency values for each site. This analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C–N bond cleavage activity, and the step atoms are the active sites for the C–N bond cleavage. When Ru nanoparticles are smaller than 1.9 nm, they have a strong adsorption effect on the reactants, which will affect the catalytic performance of the Ru catalyst. Furthermore, these findings were also confirmed on other metallic Pd/Pt catalysts. The role of step sites in C–N bond cleavage was proposed using the density function theory calculations. The reactants have stronger adsorption energies on the step atoms, and step atoms have d-band center nearer to the Fermi level. In this case, the interaction with the reactant is stronger, which is beneficial for activating the C–N bond of the reactant.

关键词： sp³/sp²-hybridized C–N bond noble metal nanoparticle catalytic active site turnover frequency DFT

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Facile synthesis and enhanced visible-light photocatalytic activity of Ti

Xiaojie Zhang,Lei Wang,Shuqing Chen,Yi Huang,Zhuonan Song,Miao Yu

《化学科学与工程前沿（英文）》 2015年第9卷第3期页码 349-358 doi: 10.1007/s11705-015-1523-5

摘要： Ti -doped TiO nanosheets with tunable phase composition (doped TiO (A/R)) were synthesized via a hydrothermal method with high surface area anatase TiO nanosheets TiO (A) as a substrate, structure directing agent, and inhibitor; the activity was evaluated using a probe reaction-photocatalytic CO conversion to methane under visible light irradiation with H as an electron donor and hydrogen source. High-resolution transmission electron microscope (HRTEM), field emission scanning electron microscope, UV-Vis diffuse reflectance spectra, and X-ray diffraction (XRD) etc., were used to characterize the photocatalysts. XRD and HRTEM measurements confirmed the existence of anatase-rutile phase junction, while Ti and single-electron-trapped oxygen vacancy in the doped TiO (A/R) photocatalyst were revealed byelectron paramagnetic resonance (EPR) measurements. Effects of hydrothermal synthesis temperature and the amount of added anatase TiO on the photocatalytic activity were elucidated. Significantly enhanced photocatalytic activity of doped TiO (A/R) was observed; under the optimized synthesis conditions, CH generation rate of doped TiO (A/R) was 2.3 times that of Ti -doped rutile TiO .

关键词： Ti³⁺-doped TiO₂ photocatalytic CO₂ conversion visible light irradiation