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Graphene-like -BN supported polyhedral NiS/NiS nanocrystals with excellent photocatalytic performance

《化学科学与工程前沿(英文)》 2021年 第15卷 第6期   页码 1537-1549 doi: 10.1007/s11705-021-2094-2

摘要: Human health is deteriorating due to the effluent containing heavy metal ions and organic dyes. Hence, photoreduction of Cr(VI) to Cr(III) and degradation of rhodamine B (RhB) using a novel photocatalyst is particularly important. In this work, h-BN/NiS2/NiS composites were prepared via a simple solvothermal method and a double Z-scheme heterojunction was constructed for efficiently removing RhB and Cr(VI). The 7 wt-% h-BN/NiS2/NiS composites were characterized via a larger specific surface area (15.12 m2·g–1), stronger light absorption capacity, excellent chemical stability, and high yield of electrons and holes. The experimental result indicated that the photoreduction efficiency of the 7 wt-% h-BN/NiS2/NiS photocatalyst achieved 98.5% for Cr(VI) after 120 min, which was about 3 times higher than that of NiS2/NiS (34%). However, the removal rate of RhB by the 7 wt-% h-BN/NiS2/NiS photocatalyst reached 80%. This is due to the double Z-scheme heterojunction formed between NiS2/NiS and h-BN, which improved the charge separation efficiency and transmission efficiency. Besides, the influence of diverse photogenerated electron and hole scavengers upon the photoreduction of Cr(VI) was studied, the results indicated that graphene-like h-BN promoted transportation of photoinduced charges on the surface of the h-BN/NiS2/NiS photocatalyst via the interfacial effects.

关键词: graphene-like h-BN     h-BN/NiS2/NiS composites     photocatalysis     Cr(VI) reduction     degradation of RhB    

Photocatalytic water splitting of ternary graphene-like photocatalyst for the photocatalytic hydrogen

Yan Zhang, Yuyan Zhang, Xue Li, Xiaohan Zhao, Cosmos Anning, John Crittenden, Xianjun Lyu

《环境科学与工程前沿(英文)》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1248-7

摘要: Abstract •The MoS2/SiC/GO composite has a strong photocatalytic activity than SiC. •The optimal catalyst yielded the highest quantum of 21.69%. •GO acts as a bridge for electron passage in photocatalytic reaction. In recent times, therehas been an increasing demand for energy which has resulted in an increased consumption of fossil fuels thereby posing a number of challenges to the environment. In the course finding possible solutions to this environmental canker, solar photocatalytic water splitting to produce hydrogengas has been identified as one of the most promising methods for generating renewable energy. To retard the recombination of photogenerated carriers and improve the efficiencyof photocatalysis, the present paper reports a facile method called the hydrothermal method, which was used to prepare ternary graphene-like photocatalyst. A “Design Expert” was used to investigate the influence of the loading weight of Mo and GO as well as the temperature of hydrothermal reaction and their interactions on the evolution of hydrogen (H2) in 4 h. The experimental results showed that the ternary graphene-like photocatalyst has a strong photocatalytic hydrogen production activity compared to that of pure SiC. In particular, the catalyst added 2.5 wt% of GO weight yielded the highest quantum of 21.69 % at 400–700 nm of wavelength. The optimal evolution H2 in 4 h conditions wasobtained as follows: The loading weight of Mo was 8.19 wt%, the loading weight of GO was 2.02 wt%, the temperature of the hydrothermal reaction was 200.93°C. Under the optimum conditions, the evolution of H2 in 4 h could reach 4.2030 mL.

关键词: Water splitting     Visible light     Graphene-like photocatalyst     Response surface methodology    

Bamboo-like -doped carbon nanotubes encapsulating M(Co, Fe)-Ni alloy for electrochemical production ofsyngas with potential-independent CO/H ratios

《化学科学与工程前沿(英文)》 2022年 第16卷 第4期   页码 498-510 doi: 10.1007/s11705-021-2082-6

摘要: The electrochemical conversion of CO2-H2O into CO-H2 using renewable energy is a promising technique for clean syngas production. Low-cost electrocatalysts to produce tunable syngas with a potential-independent CO/H2 ratio are highly desired. Herein, a series of N-doped carbon nanotubes encapsulating binary alloy nanoparticles (MxNi-NCNT, M= Fe, Co) were successfully fabricated through the co-pyrolysis of melamine and metal precursors. The MxNi-NCNT samples exhibited bamboo-like nanotubular structures with a large specific surface area and high degree of graphitization. Their electrocatalytic performance for syngas production can be tuned by changing the alloy compositions and modifying the electronic structure of the carbon nanotube through the encapsulated metal nanoparticles. Consequently, syngas with a wide range of CO/H2 ratios, from 0.5:1 to 3.4:1, can be produced on MxNi-NCNT. More importantly, stable CO/H2 ratios of 2:1 and 1.5:1, corresponding to the ratio to produce biofuels by syngas fermentation, could be realized on Co1Ni-NCNT and Co2Ni-NCNT, respectively, over a potential window of –0.8 to –1.2 V versus the reversible hydrogen electrode. Our work provides an approach to develop low-cost and potential-independent electrocatalysts to effectively produce syngas with an adjustable CO/H2 ratio from electrochemical CO2 reduction.

关键词: electrochemical reduction of CO2     syngas     N-doped carbon nanotubes     encapsulated alloy nanoparticles     CO/H2 ratio    

visible-photocatalytic hydrogen evolution and simultaneous organic pollutant degradation over an urchin-like

《环境科学与工程前沿(英文)》 2022年 第16卷 第10期 doi: 10.1007/s11783-022-1566-z

摘要:

● An urchin-like OMS/ZIS composite was fabricated by a facile solvothermal method.

关键词: Dual-functional photocatalysts     Oxygen-doped MoS2/ZnIn2S4     H2 evolution     Organic pollutant    

Engineering the electronic and geometric structure of VO/BN@TiO heterostructure for efficient aerobic

《化学科学与工程前沿(英文)》 2023年 第17卷 第3期   页码 276-287 doi: 10.1007/s11705-022-2242-3

摘要: Particle size governs the electronic and geometric structure of metal nanoparticles (NPs), shaping their catalytic performances in heterogeneous catalysis. However, precisely controlling the size of active metal NPs and thereafter their catalytic activities remain an affordable challenge in ultra-deep oxidative desulfurization (ODS) field. Herein, a series of highly-efficient VOx/boron nitride nanosheets (BNNS)@TiO2 heterostructures, therein, cetyltrimethylammonium bromide cationic surfactants serving as intercalation agent, BNNS and MXene as precursors, with various VOx NP sizes were designed and controllably constructed by a facile intercalation confinement strategy. The properties and structures of the prepared catalysts were systematically characterized by different technical methods, and their catalytic activities were investigated for aerobic ODS of dibenzothiophene (DBT). The results show that the size of VOx NPs and V5+/V4+ play decisive roles in the catalytic aerobic ODS of VOx/BNNS@TiO2 catalysts and that VOx/BNNS@TiO2-2 exhibits the highest ODS activity with 93.7% DBT conversion within 60 min under the reaction temperature of 130 °C and oxygen flow rate of 200 mL·min–1, which is due to its optimal VOx dispersion, excellent reducibility and abundant active species. Therefore, the finding here may contribute to the fundamental understanding of structure-activity in ultra-deep ODS and inspire the advancement of highly-efficient catalyst.

关键词: oxidative desulfurization     boron nitride     vanadium     MXene     intercalation confinement    

Degradation of Azo dye direct black BN based on adsorption and microwave-induced catalytic reaction

Shanshan Ding, Wen Huang, Shaogui Yang, Danjun Mao, Julong Yuan, Yuxuan Dai, Jijie Kong, Cheng Sun, Huan He, Shiyin Li, Limin Zhang

《环境科学与工程前沿(英文)》 2018年 第12卷 第1期 doi: 10.1007/s11783-017-1003-x

摘要: The novel microwave catalyst MgFe O -SiC was synthesized via sol-gel method, to remove azo dye Direct Black BN (DB BN) through adsorption and microwave-induced catalytic reaction. Microwave-induced catalytic degradation of DB BN, including adsorption behavior and its influencing factors of DB BN on MgFe O -SiC were investigated. According to the obtained results, it indicated that the pseudo-second-order kinetics model was suitable for the adsorption of DB BN onto MgFe O -SiC. Besides, the consequence of adsorption isotherm depicted that the adsorption of DB BN was in accordance with the Langmuir isotherm, which verified that the singer layer adsorption of MgFe O -SiC was dominant than the multi-layer one. The excellent adsorption capacities of MgFe O -SiC were kept in the range of initial pH from 3 to 7. In addition, it could be concluded that the degradation rate of DB BN decreased over ten percent after the adsorption equilibrium had been attained, and the results from the result of comparative experiments manifested that the adsorption process was not conducive to the process of microwave-induced catalytic degradation. The degradation intermediates and products of DB BN were identified and determined by GC-MS and LC-MS. Furthermore, combined with the catalytic mechanism of MgFe O -SiC, the proposed degradation pathways of DB BN were the involution of microwave-induced ·OH and holes in this catalytic system the breakage of azo bond, hydroxyl substitution, hydroxyl addition, nitration reaction, deamination reaction, desorbate reaction, dehydroxy group and ring-opening reaction.

关键词: Adsorption     Microwave-induced catalytic degradation     Direct black BN     Degradation pathway    

Role of oxygen vacancy inducer for graphene in graphene-containing anodes

《化学科学与工程前沿(英文)》 2023年 第17卷 第3期   页码 326-333 doi: 10.1007/s11705-022-2213-8

摘要: Currently, graphene is only considered as a conductive additive and expansion inhibitor in oxides/graphene composite anodes. In this study, a new graphene role (oxygen vacancy inducer) in graphene/oxides composites anodes, which are treated at high-temperature, is proposed and verified using experiments and density functional theory calculations. During high-temperature processing, graphene forms carbon vacancies due to increased thermal vibration, and the carbon vacancies capture oxygen atoms, facilitating the formation of oxygen vacancies in oxides. Moreover, the induced oxygen vacancy concentrations can be regulated by sintering temperatures, and the behavior is unaffected by oxide crystal structures (crystalline and amorphous) and morphology (size and shape). According to density functional theory calculations and electrochemical measurements, the oxygen vacancies enhance the lithium-ion storage performance. The findings can result in a better understanding of graphene’s roles in graphene/oxide composite anodes, and provide a new method for designing high-performance oxide anodes.

关键词: oxide     oxygen vacancy     graphene     anode     density functional theory calculation    

Ammonia adsorption on graphene and graphene oxide: a first-principles study

Yue PENG, Junhua LI

《环境科学与工程前沿(英文)》 2013年 第7卷 第3期   页码 403-411 doi: 10.1007/s11783-013-0491-6

摘要: Motivated by the recent realization of graphene sensor to detect gas molecules that are harmful to the environment, the ammonia adsorption on graphene or graphene oxide (GO) was investigated using first-principles calculation. The optimal adsorption and orientation of the NH molecules on the graphene surfaces were determined, and the adsorption energies ( ) as well as the Mulliken charge transfers of NH were calculated. The for the graphene are small and seem to be independent of the sites and orientations. The surface epoxy or hydroxyl groups can promote the adsorption of NH on the GO; the enhancement of the for the hydroxyl groups is greater than that for the epoxy groups on the surface. The charge transfers from the molecule to the surfaces also exhibit the same trend. The Br?nsted acid sites and Lewis acid sites could stably exist on the GO with surface hydroxyl groups and on the basal, respectively.

关键词: graphene oxide     first-principles calculations     NH3 adsorption    

Mechanical properties and microstructure of multilayer graphene oxide cement mortar

《结构与土木工程前沿(英文)》 2021年 第15卷 第4期   页码 1058-1070 doi: 10.1007/s11709-021-0747-3

摘要: This study reports on the effects of multilayer graphene oxide (MGO) on compressive strength, flexural strength, and microstructure of cement mortar. The cement mortar was prepared with type P. II. 52.5 Portland cement, standard sand, and MGO. Four mixes were prepared with inclusion of MGO (0%, 0.02%, 0.04%, and 0.06% by weight of cement). The testing result shows that the compressive of GO-cement mortar increased by 4.84%–13.42%, and the flexural strength increased by 4.37%–8.28% at 3 d. GO-cement mortar’s compressive strength and flexural strength at 7 d increased by 3.84%–12.08% and 2.54%–13.43%, respectively. MGO made little contribution to the increases of compressive strength and flexural strength of cement mortar at 28 d. The results of X-ray diffraction (XRD), scanning electron microscope (SEM), and nitrogen (N2) adsorption/desorption tests show that the types of hydration products and crystal grain size did not change after adding MGO. Still, it can help to improve the microstructure of the cement mortar via regulating hydration products and can provide more condensed cores to accelerate hydration. Furthermore, the regulating action of MGO for the microstructure of cement mortar at an early age was better than that at 28 d.

关键词: graphene oxide     cement     mortar     mechanical properties     microstructure    

Mechanism of ethanol/water reverse separation through a functional graphene membrane: a molecular simulation

《化学科学与工程前沿(英文)》 2023年 第17卷 第3期   页码 347-357 doi: 10.1007/s11705-022-2246-z

摘要: Reverse-selective membranes have attracted considerable interest for bioethanol production. However, to date, the reverse-separation performance of ethanol/water is poor and the separation mechanism is unclear. Graphene-based membranes with tunable apertures and functional groups have shown substantial potential for use in molecular separation. Using molecular dynamics simulations, for the first time, we reveal two-way selectivity in ethanol/water separation through functional graphene membranes. Pristine graphene (PG) exhibits reverse-selective behavior with higher ethanol fluxes than water, resulting from the preferential adsorption for ethanol. Color flow mappings show that this ethanol-permselective process is initiated by the presence of ethanol-enriched and water-barren pores; this has not been reported in previous studies. In contrast, water molecules are preferred for hydroxylated graphene membranes because of the synergistic effects of molecular sieving and functional-group attraction. A simulation of the operando condition shows that the PG membrane with an aperture size of 3.8 Å achieves good separation performance, with an ethanol/water separation factor of 34 and a flux value of 69.3 kg∙m‒2∙h‒1∙bar‒1. This study provides new insights into the reverse-selective mechanism of porous graphene membranes and a new avenue for efficient biofuel production.

关键词: reverse separation     graphene membrane     ethanol/water separation     molecular simulation    

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

《能源前沿(英文)》 2018年 第12卷 第2期   页码 233-238 doi: 10.1007/s11708-018-0529-3

摘要: Heteroatom-doping of pristine graphene is an effective route for tailoring new characteristics in terms of catalytic performance which opens up potentials for new applications in energy conversion and storage devices. Nitrogen-doped graphene (N-graphene), for instance, has shown excellent performance in many electrochemical systems involving oxygen reduction reaction (ORR), and more recently glucose oxidation. Owing to the excellent sensitivity of N-graphene, the development of highly sensitive and fast-response enzymatic biosensors is made possible. However, a question that needs to be addressed is whether or not improving the anodic response to glucose detection leads to a higher overall performance of enzymatic biofuel cell (eBFC). Thus, here we first synthesized N-graphene via a catalyst-free single-step thermal process, and made use of it as the biocatalyst support in a membraneless eBFC to identify its role in altering the performance characteristics. Our findings demonstrate that the electron accepting nitrogen sites in the graphene structure enhances the electron transfer efficiency between the mediator (redox polymer), redox active site of the enzymes, and electrode surface. Moreover, the best performance in terms of power output and current density of eBFCs was observed when the bioanode was modified with highly doped N-graphene.

关键词: enzymatic fuel cell     nitrogen-doped graphene     reduced graphene oxide     catalyst-free synthesis    

Effect of graphene and its derivatives on thermo-mechanical properties of phase change materials and

《能源前沿(英文)》 2022年 第16卷 第2期   页码 150-186 doi: 10.1007/s11708-021-0795-3

摘要: Phase change materials (PCMs) play a leading role in overcoming the growing need of advanced thermal management for the storage and release of thermal energy which is to be used for different solar applications. However, the effectiveness of PCMs is greatly affected by their poor thermal conductivity. Therefore, in the present review the progress made in deploying the graphene (Gr) in PCMs in the last decade for providing the solution to the aforementioned inadequacy is presented and discussed in detail. Gr and its derivatives ((Gr oxide (GO), Gr aerogel (GA) and Gr nanoplatelets (GNPs)) based PCMs can improve the thermal conductivity and shape stability, which may be attributed to the extra ordinary thermo-physical properties of Gr. Moreover, it is expected from this review that the advantages and disadvantages of using Gr nanoparticles provide a deep insight and help the researchers in finding out the exact basic properties and finally the applications of Gr can be enhanced.

关键词: phase change materials (PCMs)     graphene     thermal conductivity     characterization    

Enhanced permeability and biofouling mitigation of forward osmosis membranes via grafting graphene quantum

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1470-1483 doi: 10.1007/s11705-023-2329-5

摘要: In this paper, graphene oxide quantum dots with amino groups (NH2-GOQDs) were tailored to the surface of a thin-film composite (TFC) membrane surface for optimizing forward osmosis (FO) membrane performance using the amide coupling reaction. The results jointly demonstrated hydrophilicity and surface roughness of the membrane enhanced after grafting NH2-GOQDs, leading to the optimized affinity and the contact area between the membrane and water molecules. Therefore, grafting of the membrane with a concentration of 100 ppm (TFC-100) exhibited excellent permeability performance (58.32 L·m–2·h–1) compared with TFC membrane (16.94 L·m–2·h–1). In the evaluation of static antibacterial properties of membranes, TFC-100 membrane destroyed the cell morphology of Escherichia coli (E. coli) and reduced the degree of bacterial adsorption. In the dynamic biofouling experiment, TFC-100 membrane showed a lower flux decline than TFC membrane. After the physical cleaning, the flux of TFC-100 membrane could recover to 96% of the initial flux, which was notably better than that of TFC membrane (63%). Additionally, the extended Derjaguin–Landau–Verwey–Overbeek analysis of the affinity between pollutants and membrane surface verified that NH2-GOQDs alleviates E. coli contamination of membrane. This work highlights the potential applications of NH2-GOQDs for optimizing permeability and biofouling mitigation of FO membranes.

关键词: forward osmosis membrane     graphene oxide quantum dots     graft modification     anti-fouling membrane     XDLVO theory    

Electrocatalytic debromination of BDE-47 at palladized graphene electrode

Hongtao YU, Bin MA, Shuo CHEN, Qian ZHAO, Xie QUAN, Shahzad AFZAL

《环境科学与工程前沿(英文)》 2014年 第8卷 第2期   页码 180-187 doi: 10.1007/s11783-013-0552-x

摘要: Graphene electrodes (Ti/Gr) were prepared by depositing Gr sheets on Ti substrate, followed by an annealing process for enhancing the adhesion strength. Electrochemical impedance spectroscopies and X-ray diffraction patterns displayed that the electrochemical behavior of Ti/Gr electrodes can be improved due to the generation of TiO layer at Ti-Gr interface during the annealing process. The palladized Gr electrodes (Ti/Gr/Pd) were prepared by electrochemical depositing Pd nanoparticles on Gr sheets. The debromination ability of Ti/Gr/Pd electrodes was investigated using BDE-47 as a target pollutant with various bias potentials. The results indicated that the BDE-47 degradation rates on Ti/Gr/Pd electrodes increased with the negative bias potentials from 0 V to -0.5 V (vs. SCE). Almost all of the BDE-47 was removed in the debromination reaction on the Ti/Gr/Pd electrode at -0.5 V for 3 h, and the main product was diphenyl ethers, meaning it is promising to debrominate completely using the Ti/Gr/Pd electrode. Although the debromination rate was slightly slower at -0.3 V than that under -0.5 V, the current efficiency at -0.3 V was higher, because the electrical current acted mostly on BDE-47 rather than on water.

关键词: graphene     palladium     debromination     BDE-47    

Synthesis of hydrophobic carbon nanotubes/reduced graphene oxide composite films by flash light irradiation

Kai Wang, Jinbo Pang, Liwei Li, Shengzhe Zhou, Yuhao Li, Tiezhu Zhang

《化学科学与工程前沿(英文)》 2018年 第12卷 第3期   页码 376-382 doi: 10.1007/s11705-018-1705-z

摘要:

Carbon nanotubes/graphene composites have superior mechanical, electrical and electrochemistry properties with carbon nanotubes as a hydrophobicity boosting agent. Their extraordinary hydrophobic performance is highly suitable for electrode applications in lithium ion batteries and supercapacitors which often employ organic electrolytes. Also the hydrophobic features enable the oil enrichment for the crude oil separation from seawater. The ever reported synthesis routes towards such a composite either involve complicated multi-step reactions, e.g., chemical vapor depositions, or lead to insufficient extrusion of carbon nanotubes in the chemical reductions of graphene oxide, e.g., fully embedding between the compact graphene oxide sheets. As a consequence, the formation of standalone carbon nanotubes over graphene sheets remains of high interests. Herein we use the facile flash light irradiation method to induce the reduction of graphene oxides in the presence of carbon nanotubes. Photographs, micrographs, X-ray diffraction, infrared spectroscopy and thermogravimetric analysis all indicate that graphene oxides has been reduced. And the contact angle tests confirm the excellent hydrophobic performances of the synthesized carbon nanotube/reduced graphene oxide composite films. This one-step treatment represents a straightforward and high efficiency way for the reduction of carbon nanotubes/graphene oxides composites.

关键词: carbon nanotubes     graphene composite     flash irradiation method     reduced graphene oxide     contact angles    

标题 作者 时间 类型 操作

Graphene-like -BN supported polyhedral NiS/NiS nanocrystals with excellent photocatalytic performance

期刊论文

Photocatalytic water splitting of ternary graphene-like photocatalyst for the photocatalytic hydrogen

Yan Zhang, Yuyan Zhang, Xue Li, Xiaohan Zhao, Cosmos Anning, John Crittenden, Xianjun Lyu

期刊论文

Bamboo-like -doped carbon nanotubes encapsulating M(Co, Fe)-Ni alloy for electrochemical production ofsyngas with potential-independent CO/H ratios

期刊论文

visible-photocatalytic hydrogen evolution and simultaneous organic pollutant degradation over an urchin-like

期刊论文

Engineering the electronic and geometric structure of VO/BN@TiO heterostructure for efficient aerobic

期刊论文

Degradation of Azo dye direct black BN based on adsorption and microwave-induced catalytic reaction

Shanshan Ding, Wen Huang, Shaogui Yang, Danjun Mao, Julong Yuan, Yuxuan Dai, Jijie Kong, Cheng Sun, Huan He, Shiyin Li, Limin Zhang

期刊论文

Role of oxygen vacancy inducer for graphene in graphene-containing anodes

期刊论文

Ammonia adsorption on graphene and graphene oxide: a first-principles study

Yue PENG, Junhua LI

期刊论文

Mechanical properties and microstructure of multilayer graphene oxide cement mortar

期刊论文

Mechanism of ethanol/water reverse separation through a functional graphene membrane: a molecular simulation

期刊论文

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

期刊论文

Effect of graphene and its derivatives on thermo-mechanical properties of phase change materials and

期刊论文

Enhanced permeability and biofouling mitigation of forward osmosis membranes via grafting graphene quantum

期刊论文

Electrocatalytic debromination of BDE-47 at palladized graphene electrode

Hongtao YU, Bin MA, Shuo CHEN, Qian ZHAO, Xie QUAN, Shahzad AFZAL

期刊论文

Synthesis of hydrophobic carbon nanotubes/reduced graphene oxide composite films by flash light irradiation

Kai Wang, Jinbo Pang, Liwei Li, Shengzhe Zhou, Yuhao Li, Tiezhu Zhang

期刊论文