检索结果-南通市图书馆

Nano Research 2017年第9期10卷 2954-2965页

作者： bolun wang Guodong Wen Dangsheng SU Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Materials Science and Engineering University of Science and Technology of China Hefei 230026 China Department of Inorganic Chemistry Fritz Haber Institute of the Max Planck Society Berlin 14195 Germany

The acid-catalyzed ring-opening reaction of styrene oxide was used as a probe reaction for evaluating the acidic properties of carboxylated carbocatalysts. Significant discrepancies in the initial reaction rates were normalized using the total number of carboxyl groups, and demonstrated that the average catalytic activities of the carboxyl moieties on the carbocatalysts differed. Comparisons between the apparent activation energy E a and the pre-exponential factor A, derived from Arrhenius analysis, demonstrated that A varied more significantly, and therefore had a more significant effect on the reaction rates than E a. The variation in the calculated pKa values of the carboxyl groups was attributed to the electronic effects of the nitro groups. This hypothesis was supported by the temperature programmed desorption profiles of nitrogen monoxide ions.

关键词： carboxylated carbocatalysts acidic properties ring-opening reaction Arrhenius analysis pKa values electronic effect

Photoluminescent chiral carbon dots derived from glutamine

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第12期32卷 3916-3920页

作者： Wenyan Ma bolun wang Yonggang Yang Jiyang Li State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application Department of Polymer Science and Engineering College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China

The integration of luminescence and chirality in carbon dots(CDs) encourages candidates to explore novel functions and applications of CDs, however, the preparation of chiral CDs is very limited. Herein, we report a hydrothermal method to fabricate chiral CDs by utilizing amino acid enantiomers as the precursors. LGln-CDs or DGln-CDs with uniform size of 3–4 nm show excitation-dependent blue fluorescence in solutions. Circular dichroism measurement confirms the opposite optical rotation of chiral CDs in the region from 200 nm to 300 nm, and the signals can be regulated by concentrations of CDs solution. Timedependent density functional calculation reveals that polypeptides may exist on the surface of CDs due to the polycondensation of L/DGln at high temperature, and the optical activity of CDs originates from the stacking of neighboring carbonyl groups. The facile synthetic methodology proposed will provide potential opportunities for the preparation and application of chiral and chiroptical CDs-based materials.

关键词： Chirality Carbon dots Photoluminescence Circular dichroism Sensors

Carbon Dots Derived from Coffee Residue for Sensitive and Selective Detection of Picric Acid and Iron(III)Ions

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2021年第3期37卷 623-628页

作者： ZONG Siyu wang bolun MA Wenyan YAN Yan LI Jiyang University Changchun130012P.R.China

A facile method was developed to prepare carbon dots(CDs)by pyrolysis and etching of coffee *** as-prepared CDs show uniform spherical nanoparticles with an average size of 2.3 nm and exhibit excitation-dependent fluorescence ***,CDs also exhibit strong fluorescence quenching to nitro compounds and metal ions in both water and ethanol solutions,which could act as a platform for dual detection of PA(picric acid)and Fe^(3+)ions with low detection limits of 0.26 and 0.83µmol/L,*** work provides a novel method for preparation of environmental-friendly fluorescent CDs and shows their potential applications in photoluminescence sensors.

关键词： Carbon dot Coffee residue Luminescence Detection

Calcination-controlled fabrication of carbon dots@zeolite composites with multicolor fluorescence and phosphorescence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2022年第10期15卷 9454-9460页

作者： Siyu Zong bolun wang Xin Yin Wenyan Ma Jiani Zhang Jiyang Li State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China

In light of the exceptional optical qualities,luminous carbon dots(CDs),particularly those with room-temperature phosphorescence(RTP),have a wide range of applications in a variety of ***,modulating afterglow emissions practically and efficiently remains a serious ***,a feasible strategy of calcination combined with in-situ synthesis is proposed to fabricate CDs-based composites with multicolor fluorescence(FL)and *** pre-selection of small pore RHO zeolite as a matrix,CDs have been successfully embedded due to strong guest–host interaction achieved by insitu hydrothermal *** the unique pore architecture and excellent stability of the zeolite matrix,the surface oxidation degree and the carbon core size of confined CDs are engineered by temperature-controlled *** resulting composites exhibit tunable FL(from 416 to 566 nm)and RTP(from 440 to 585 nm)in solid and aqueous solution,in which rarely occurring deep blue RTP is observed with a lifetime as long as 573 ***,the universality of such a calcination-modulated luminescent method has been proved by the AFI zeolite *** study offers up a new way to regulate the luminescence of CDs facilitated by matrix,which considerably promotes the potential applications of CDs-based composites in the future.

关键词： carbon dots zeolite tunable phosphorescence calcination modulation host-guest

The power of comments： fostering social interactions in microblog networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2016年第5期10卷 889-907页

作者： Tianyi wang Yang CHEN Yi wang bolun wang Gang wang Xing LI Haitao ZHENG Ben Y. ZHAO Department of Electronic Engineering Tsinghua University Beijing 100084 China Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China Department of Computer Science University of California Santa Barbara CA 93106-5110 USA School of Computer Science Fudan University Shanghai 201203 China Department of Mathematics Syracuse University Syracuse NY 13244-1150 USA

Today＇s ubiquitous online social networks serve multiple purposes, including social communication （Face- book, Renren）, and news dissemination （Twitter）. But how does a social network＇s design define its functionality？ An- swering this would need social network providers to take a proactive role in defining and guiding user behavior. In this paper, we first take a step to answer this question with a data-driven approach, through measurement and anal- ysis of the Sina Weibo microblogging service. Often com- pared to Twitter because of its format, Weibo is interesting for our analysis because it serves as a social communication tool and a platform for news dissemination, too. While similar to Twitter in functionality, Weibo provides a distinguishing feature, comments, allowing users to form threaded con- versations around a single tweet. Our study focuses on this feature, and how it contributes to interactions and improves social engagement. We use analysis of comment interactions to uncover their role in social interactivity, and use comment graphs to demonstrate the structure of Weibo users interac- tions. Finally, we present a case study that shows the impact of comments in malicious user detection, a key application on microblogging systems. That is, using properties of com- ments significantly improves the accuracy in both modeling and detection of malicious users.

关键词： microblogs comments social and interactiongraph user behavior

Modulating hydrothermal condition to achieve carbon dots-zeolite composites with multicolor afterglow

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第5期16卷 7761-7769页

作者： Jiali Wen Zhifeng Zeng bolun wang Junyu Hong Yingyuan Chen Jianyu Zhang Jiyang Li Jiuxing Jiang MOE Key Laboratory of Bioinorganic and Synthetic Chemistry School of ChemistrySun Yat-sen UniversityGuangzhou 510006China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China Department of Chemistry Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and ReconstructionThe Hong Kong University of Science and TechnologyKowloonHong Kong 999077China Guangdong Provincial Key Laboratory of Optical Chemicals XinHuaYue GroupMaoming 525000China

Responsive luminescence materials with prolonged lifetime and multicolor emission have drawn great attention due to their attractive optical property and potential ***,two responsive carbon dots(CDs)based composites:CD_(1)@MCM-22P and CD_(2)@ZSM-12 were achieved by a one-step hydrothermal *** adjusting the hydrothermal condition,CD_(1)@MCM-22P owns temperature-dependent afterglow,while CD_(2)@ZSM-12 is equipped with excitation-dependent room-temperature *** photoluminescence mechanisms of CD1@MCM-22P and CD_(2)@ZSM-12 were investigated and proposed,and the composites were applied in multi-mode *** work provides an insight as well as a feasible method for the development of multi-emissive CDs@zeolite composite.

关键词： carbon dots zeolitic matrices responsive photoluminescence room-temperature phosphorescence thermally activated delayed fluorescence

Confining carbon dots in amino-functionalized mesoporous silica:n→π^(*) interaction triggered deep-red solid-state fluorescence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第3期16卷 4170-4177页

作者： Hongyue Zhang Qingyi Li Shuo wang Xiaowei Yu bolun wang Guangrui Chen Li Ren Jiyang Li Mingxing Jin Jihong Yu State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China Key Laboratory for Molecular Enzymology and Engineering The Ministry of EducationJilin UniversityChangchun 130012China International Center of Future Science Jilin UniversityChangchun 130012China

Deep-red and near-infrared emissive carbon dots(CDs)are highly desired for bioimaging,especially in deep tissue imaging,but they are extremely rare and the known ones usually suffer from low-efficient fluorescence in water and aggregation-induced fluorescence quenching in solid *** this work,CDs with intriguing solvent-dependent and two-photon fluorescence emissions have been prepared by a facile solvothermal *** characterizations reveal that there is an n→π*interaction between the carboxyl functional groups on CDs and the electron donor groups in solvent,which leads to the increase of energy density of CDs and the decrease of energy level,resulting in the red shift of luminescence with enhanced electron donating ability of *** by this finding,mesoporous silica nanoparticles(MSNs)with suitable pore size and low biological toxicity are modified by amino groups to confine CDs,thus the deep-red fluorescence emission is achieved both in solid state and in water facilitated by the n→π*interaction of *** as-prepared CDs@EDA-MSN composite exhibits high-efficient fluorescence with 650 nm wavelength,low toxicity,and good biocompatibility,which endow them a promising application in bio-imaging.

关键词： carbon dots mesoporous silica deep-red fluorescence donor-acceptor modulation bioimaging

Versatile memristor implemented in van der Waals CuInP_(2)S_(6)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2023年第7期16卷 10191-10197页

作者： Yiqun Liu Yonghuang Wu bolun wang Hetian Chen Di Yi Kai Liu Ce-Wen Nan Jing Ma State Key Lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Memristors are playing an increasingly important role in developing in-memory *** memristors which offer both volatile and non-volatile performances can be employed as both memories and selectors,displaying unique advantages for developing novel electronic ***,the remarkable multifunctional memristor with switchable operating modes between volatile and non-volatile by regulating compliance currents is implemented in Ag/CIPS/Au(CIPS:CuInP_(2)S_(6))***-like volatile memristor performances with the rectification ratio of 10^(3) and an endurance of 500 switching cycles were ***,significant non-volatile memory performances with on/off ratio of 10^(3)and retention up to 10^(4)s were also developed,which enables it to be utilized as selectors and memories ***,such versatile memristor can emulate the short-term plasticity(STP)and long-term plasticity(LTP)of artificial synapse,demonstrating its advantages in neuromorphic computing applications.

关键词： CuInP_(2)S_(6)(CIPS) versatile memristor conductive filament synaptic plasticity

Effects of soaking process on arsenic and other mineral elements in brown rice

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2020年第2期9卷 168-175页

作者： Fan Zhang Fengying Gu Huili Yan Zhenyan He bolun wang Hao Liu Tingting Yang Feng wang Institute of Food Science and Technology Chinese Academy of Agricultural SciencesBeijing 100193China Key Laboratory of Agro-Products Processing Ministry of AgricultureBeijing 100193China Graduate School of Chinese Academy of Agricultural Sciences Beijing 100081China Institute of Botany Chinese Academy of SciencesBeijing 100093China

One of the main food crops in the world,rice can accumulate high levels of arsenic from flooded paddy soils,which seriously threatens human ***,a common processing method for brown rice products,especially for brown rice noodles,was investigated in this *** rice(Dao Hua Xiang No.2)and Indica rice(Ye Xiang You No.3)were selected for studying the effects of soaking on arsenic concentrations,species,and *** revealed that soaking can efficiently remove arsenic in these two rice varieties,and the main part of removal is endosperm with the maximal rate of about 40%.Inorganic arsenic(I-As)(about 85%)is the main species of arsenic ***,the variations of four other elements(i.e.,Mg,Ca,Zn,and Fe)were ***,the findings of this study indicate that soaking can efficiently remove arsenic in brown rice under controlled soaking conditions,which thereby reduces the arsenic intake for brown rice customers.

关键词： Brown rice Soaking Total arsenic Arsenic species Distribution

Direct laser patterning of two-dimensional lateral transition metal disulfide-oxide-disulfide heterostructures for ultrasensitive sensors

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nano Research 2020年第8期13卷 2035-2043页

作者： bolun wang Hao Luo Xuewen wang Enze wang Yufei Sun Yu-Chien Tsai Jinxuan Dong Peng Liu Huanglong Li Yong Xu Sefaattin Tongay Kaili Jiang Shoushan Fan Kai Liu State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center Tsinghua UniversityBeijing100084China State Key Laboratory of Low-Dimensional Quantum Physics Department of PhysicsTsinghua UniversityBeijing100084China Department of Precision Instrument Center for Brain Inspired Computing ResearchTsinghua UniversityBeijing100084China RIKEN Center for Emergent Matter Science(CEMS) WakoSaitama351-0198Japan School for Engineering of Matter Transport and EnergyArizona State UniversityTempeAZ85287USA

Two-dimensional(2D)heterostructures based on the combination of transition metal dichalcogenides(TMDs)and transition metal oxides(TMOs)have aroused growing attention due to their integrated merits of both components and multiple ***,nondestructive approaches of constructing TMD-TMO heterostructures are still very ***,we develop a novel type of lateral TMD-TMO heterostructure(NbS2-Nb2O5-NbS2)using a simple lithography-free,direct laser-patterning *** perfect contact of an ultrathin TMO channel(Nb2O5)with two metallic TMDs(NbS2)electrodes guarantee strong electrical signals in a two-terminal *** from sensing mechanisms in separate TMOs or TMDs,this sensor works based on the modulation of surface conduction of the ultrathin TMO(Nb2O5)channel through an adsorbed layer of water *** sensor thus exhibits high selectivity and ultrahigh sensitivity for room-temperature detection of NH3(ΔR/R=80%at 50 ppm),superior to the reported NH3 sensors based on 2D materials,and a positive temperature coefficient of resistance as high as 15%–20%/℃.Bending-invariant performance and high reliability are also demonstrated in flexible versions of *** work provides a new strategy of lithography-free processing of novel TMD-TMO heterostructures towards high-performance sensors,showing great potential in the applications of future portable and wearable electronics.

关键词： two-dimensional heterostructure niobium disulfide niobium oxide laser patterning sensor