Proceedings. International Meshing Roundtable最新文献

Controlling Intermolecular H-atom Abstraction with Ultrafast Pump-Push-Probe Spectroscopy 用超快泵推探针光谱控制分子间h原子萃取

Proceedings. International Meshing Roundtable Pub Date : 2020-09-29 DOI: 10.33263/proceedings22.032032

{"title":"Controlling Intermolecular H-atom Abstraction with Ultrafast Pump-Push-Probe Spectroscopy","authors":"","doi":"10.33263/proceedings22.032032","DOIUrl":"https://doi.org/10.33263/proceedings22.032032","url":null,"abstract":"We utilize ultrafast multi-pulse pump-push-probe transient absorption spectroscopy and time-resolved photoluminescence to monitor excited-state H-atom transfer from hydroxylic compounds to the heptazine derivative 2,5,8-tris(4-methoxyphenyl)-1,3,5,6,7,9,9b-heptaazaphenalene (TAHz). The heptazine moiety is structurally related to the monomer unit of the ubiquitous organic polymeric photocatalyst, carbon nitride. We show that TAHz can photochemically abstract an H-atom from water, in addition to generating H2 in aqueous suspensions with photocatalytic activity matching that of carbon nitride. In our multi-pulse experiment, we use resonant pump pulse to photoexcite TAHz to a bright high-lying excited state, and after a relaxation period of roughly 6 ps, we use a NIR (1150 nm) pulse to “push” the chromophore to a higher-lying excited state. When phenol is present, the push induces a persistent decrease (ΔΔOD) in the initial excited-state absorption, indicating the push pulse engenders a divergence in the photochemical branching ratios. In the presence of electron-donating substituted phenols, the magnitude of ΔΔOD diminishes markedly due to the increased excited-state reactivity of the complex accompanied by the cathodic shift in the phenol oxidation potential. Thus, the H-atom abstraction appears to proceed without aid from the additional energy of the push pulse. These results reveal new insight into the branching ratio among unreactive localized heptazine excited states and reactive intermolecular charge transfer states of H-bonded heptazine chromophores. More generally, this work provides new insight into molecular design strategies to control the excited-state photochemistry of aza-aromatic materials toward important reactions such as H-atom abstraction from water.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90764838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Photocatalytic CO2 Reduction and Thermal Properties of Alumina/Silica Coated TiO2 Nanoparticles 氧化铝/二氧化硅包覆TiO2纳米颗粒的光催化CO2还原及热性能

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.047047

{"title":"Photocatalytic CO2 Reduction and Thermal Properties of Alumina/Silica Coated TiO2 Nanoparticles","authors":"","doi":"10.33263/proceedings22.047047","DOIUrl":"https://doi.org/10.33263/proceedings22.047047","url":null,"abstract":"In this study, the surface of TiO2 was coated with SiO2 and Al2O3 layers by sol-gel and chemical deposition methods. Firstly, the TiCl4 was magnetically stirred for 1 h in deionized water, and then the NaOH solution was drop wised to the solution and stirred 2h. Finally, the obtained TiO2 was washed, filtered, and dried in a vacuum oven. The surface of TiO2 was coated with SiO2 and Al2O3 layers subsequently by chemical deposition methods. The morphological, thermal, and crystal properties of products were determined via SEM, TGA, and XRD machines. The X-ray diffraction peaks displayed that the TiO2 nanoparticles were synthesized without any extra peaks. Moreover, the SiO2 and Al2O3 coated TiO2 particles contain extra SiO2 and Al2O3 peaks, indicating that the surface of TiO2 was coated via SiO2 and Al2O3. The SEM results displayed that TiO2 and SiO2 and Al2O3 coated TiO2 were spherical in shape, and the size distribution was found to be around 20-50 nm and 200-300 nm, respectively. The photocatalytic and UV–vis analyses were used to determine the CO2 reduction and optical properties of particles. The results showed that the absorption peaks were broad to longer wavelength with a coating of SiO2 and Al2O3. The CO2 reduction performance of TiO2 has been enhanced via coating SiO2 and Al2O3 layer.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"310 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78109958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design, Analysis and Finite Element Modeling of Macro Fiber Composite Piezoelectric Materials 宏观纤维复合压电材料的设计、分析与有限元建模

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.024024

引用次数: 0

New Technologies and Processes Toward Sustainable Society 迈向可持续发展社会的新技术和新过程

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.007008

引用次数: 0

Li-ion Battery Research in Hierarchical Green-Energy Materials Research Center 分级绿色能源材料研究中心锂离子电池研究

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.004005

{"title":"Li-ion Battery Research in Hierarchical Green-Energy Materials Research Center","authors":"","doi":"10.33263/proceedings22.004005","DOIUrl":"https://doi.org/10.33263/proceedings22.004005","url":null,"abstract":"Hierarchical Green-Energy Research Center aims to promote materials innovation of Li-ion battery (LIB) for electric scooter and MWh class energy storage. Our team has mainly developed strategies for material optimization and research methodology for the improvement of electric power and cyclic stability of LIB. Metal oxides are abundant in defect structures that determine electric conductance and electrochemical activity. The first principle calculation of lithium titanate (LTO) was applied to access the electronic structure of pristine LTO and aliovalent ion-doping LTO. The other oxides were chosen as nanostructured anode materials anchored on reduced graphene oxide. We found that their cyclic ability is significantly improved due to the structurally synergetic effect between oxide nanocrystallite and substrate; Si is regarded as one of the most popular anode materials for 3rd generation LIB, but its cycle life is still limited by an overgrowth of secondary electrolyte interface (SEI). Glucose-derived Si-O-C ligand in modified SEI possessed a high affinity to Li-chelation, thus alleviating volume expansion and structural instability. Electrolyte design is considered the current technical bottleneck for the implementation of high voltage LIB. An ionic liquid hybrid electrolyte has been demonstrated excellent oxidation potential of the carbonate solvent, resistance to Al corrosion, and potential of ~5.0 V (vs. Li+/Li) even at an operating temperature of 55oC. Another highlight in the center is gel polymer electrolyte (GPE) that enables enhancement of lithium-ion transference number of 0.57 by the existence of the imidazolium group. The newly designed GPE guaranteed effective Li+ pathways in electrolyte bulk and at electrode/electrolyte interfaces, a high potential of 5.4 V, and simplicity of electrolyte synthesis and all-solid-state battery assembly for industrial-scale production processes.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"514 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78847541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Development and Application of Wooden Materials in Turkish Arts 土耳其艺术中木质材料的发展与应用

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.031031

引用次数: 0

Near-Infrared Photothermal Therapy Cancer Treatment Assisted with Graphene-Based Materials 石墨烯基材料辅助近红外光热治疗癌症

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.026026

引用次数: 0

Composite Epoxy-Graphite Materials and Their Electrochemical Application 环氧-石墨复合材料及其电化学应用

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.027028

{"title":"Composite Epoxy-Graphite Materials and Their Electrochemical Application","authors":"","doi":"10.33263/proceedings22.027028","DOIUrl":"https://doi.org/10.33263/proceedings22.027028","url":null,"abstract":"A great deal of attention has been given to the use of graphite in composite materials, taking advantage of their exceptional mechanical and electrical properties for developing electrochemical platforms and can also be easily modified, allowing the incorporation of different components. Various epoxy-graphite composites modified with benzoic acid, graphene oxide, and hydrotalcite were developed. The epoxy-graphite composites were characterized by cyclic voltammetry; electrochemical impedance spectroscopy, and field-emission scanning electron microscopy. The electrochemical behavior of the composites was analyzed from the reversibility of the Fe(CN)63-/Fe(CN)64- as a redox probe by the dependency of peak potential, the anode current relationship, and cathodic current with scan rate. Besides the advantage of being prepared by a simple and not costly procedure, the hydrotalcite-modified graphite-epoxy composite indicating the possible application of electrode for ionic exchange of positive species and potential for electroanalytical purposes; and the epoxy-graphite composite electrodes modified whit benzoic acid and graphene oxide offer both the possibility of obtaining electrochemical response at low concentrations of free DNA base and single DNA, and the required binding groups on the electrode surface for covalent immobilization of specific oligonucleotides. From the study of the electrochemical properties of epoxy-graphite composites, it was possible to determine: Lapachol, nitrogenous bases, oligonucleotides, single strands of Calf thymus DNA, and proviral DNA of HIV-1 in the clinical sample.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"263 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76537469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Density Functional Theory Study of Bone Tissues: the Role of Water in Conferring Bone Strength 骨组织的密度功能理论研究:水在赋予骨强度中的作用

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.025025

{"title":"Density Functional Theory Study of Bone Tissues: the Role of Water in Conferring Bone Strength","authors":"","doi":"10.33263/proceedings22.025025","DOIUrl":"https://doi.org/10.33263/proceedings22.025025","url":null,"abstract":"The unsurpassed mechanical properties of biomaterials stem from the intricate organization of inorganic and organic matter across length scales. In bone, water facilitates this organization, thereby playing an important structural role in addition to being a nutrient and waste transport medium. Water makes 10% of mammalian bone tissues and can be found in one of two states: bound (to the mineral phase) or mobile. While experimental studies were able to directly link the amount of bound water to bone strength, a molecular understanding of the interactions between the mineral (hydroxyapatite), organic (collagen) phase, and water is missing. In this talk, I will provide new insights into the water adsorption properties of bone tissues. I will present DFT calculations of water adsorption energy as a function of the environment, which includes an explicit solvent and human collagen fragments. I will show that the environment - rather than the mineral surface itself-governs the adsorption strength and mode. In particular, I will show that conditions consistent with aging tissues are associated with a lower density of adsorbed water molecules, which is a sign of weaker bones.","PeriodicalId":90703,"journal":{"name":"Proceedings. International Meshing Roundtable","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86913594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Theoretical Investigation of Thermal Expansion Coefficients of SiC Reinforced Copper Matrix Composites SiC增强铜基复合材料热膨胀系数的理论研究

Proceedings. International Meshing Roundtable Pub Date : 2020-09-27 DOI: 10.33263/proceedings22.022022

引用次数: 0