Interfacial Charge Transfer Induced Electronic Property Tuning of MoS_2 by Molecular Functionalization

The modulation of electrical properties of MoS_2 has attracted extensive research interest because of its potential applications in electronic and optoelectronic devices.Herein,interfacial charge transfer induced electronic property tuning of MoS_2 are investigated by in situ ultraviolet photoelectron spectroscopy and x-ray photoelectron spectroscopy measurements.A downward band-bending of MoS_2-related electronic states along with the decreasing work function,which are induced by the electron transfer from Cs overlayers to MoS_2,is observed after the functionalization of MoS_2 with Cs,leading to n-type doping.Meanwhile,when MoS_2 is modified with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane(F_4-TCNQ),an upward band-bending of MoS_2-related electronic states along with the increasing work function is observed at the interfaces.This is attributed to the electron depletion within MoS_2 due to the strong electron withdrawing property of F_4-TCNQ,indicating p-type doping of MoS_2.Our findings reveal that surface transfer doping is an effective approach for electronic property tuning of MoS_2 and paves the way to optimize its performance in electronic and optoelectronic devices.     

Nonlinear Modeling Study of Aerodynamic Characteristics of an X38-like Vehicle at Strong Viscous Interaction Regions

Strong viscous interaction and multiple flow regimes exist when vehicles fly at high altitude and high Mach number conditions. The Navier–Stokes(NS) solver is no longer applicable in the above situation. Instead, the direct simulation Monte Carlo (DSMC) method or Boltzmann model equation solvers are usually needed. However, they are computationally more expensive than the NS solver. Therefore, it is of great engineering value to establish the aerodynamic prediction model of vehicles at high altitude and high Mach number conditions. In this paper, the hypersonic aerodynamic characteristics of an X38-like vehicle in typical conditions from 70 km to 110 km are simulated using the unified gas kinetic scheme (UGKS), which is applicable for all flow regimes. The contributions of pressure and viscous stress on the force coefficients are analyzed. The viscous interaction parameters, Mach number, and angle of attack are used as independent variables, and the difference between the force coefficients calculated by UGKS and the Euler solver is used as a dependent variable to establish a nonlinear viscous interaction model between them in the range of 70–110 km. The evaluation of the model is completed using the correlation coefficient and the relative orthogonal distance. The conventional viscous interaction effect and rarefied effect are both taken into account in the model. The model can be used to quickly obtain the hypersonic aerodynamic characteristics of X38-like vehicle in a wide range, which is meaningful for engineering design.     

Soliton solution and interaction property for a coupled modified Korteweg-de Vries （mKdV） system

Hirota＇s bilinear direct method is applied to constructing soliton solutions to a special coupled modified Korteweg- de Vries （mKdV） system. Some physical properties such as the spatiotemporal evolution, waveform structure, interactive phenomena of solitons are discussed, especially in the two-soliton case. It is found that different interactive behaviours of solitary waves take place under different parameter conditions of overtaking collision in this system. It is verified that the elastic interaction phenomena exist in this （1＋1）-dimensional integrable coupled model.     

241Am-Be中子参考辐射的蒙特卡罗模拟研究

研究用于校准场所中子剂量监测仪表的241Am-Be中子参考辐射场计量特性。采用蒙特卡罗方法模拟了空气自由中子参考辐射(FRNR),GB/T 14055规定的最小尺寸中子参考辐射(SRNR)和实际中子参考辐射(ARNR)中不同检验点处中子周围剂量当量率、散射中子占比和能谱分布特征。研究结果表明,空气对FRNR中的剂量率和能谱分布影响小,近似为理想中子参考辐射;采用5%含硼聚乙烯作屏蔽的最小尺寸SRNR可减少热中子,降低散射中子占比,影锥法不适用于小尺寸中子参考辐射中对散射中子的修正;ARNR中的散射中子更少、占比更低,影锥法所得散射中子占比与理论值基本一致。     

Combining Metabolic Alkyne Labeling and Click Chemistry for Secretome Analysis of Serum-Containing Conditioned Medium

Main observation and conclusion Bioorthogonal click chemistry has emerged as a powerful tool for the specific modification of proteins in complex mixtures.Metab...     

One-step synthesis ofα,β-unsaturated arylsulfones by a novel multicomponent reaction of aromatic aldehydes,chloroacetonitrile, benzenesulfinic acid sodium salt

A new and green method for the synthesis of α,β-unsaturated arylsulfones had been achieved through the condensation of aromatic aldehydes,chloroacetonitrile,benzenesulfinic acid sodium salt in the presence of l-butyl-3-methyl imidazolium hydroxide([bmim]OH) in EtOH under reflux.The ionic liquid was recovered and recycled for subsequent reactions.The advantages of this protocol were non-toxic,easy work-up and good yields.     

Triple condensation of aryl methyl ketones catalyzed by amine and trifluoroacetic acid: straightforward access to 1,3,5-triarylbenzenes under mild conditions

An efficient triple condensation reaction of aryl methyl ketones catalyzed by ethylenediamine and trifluoroacetic acid was reported. A broad scope of 1,3,5-triarylbenzenes was obtained in good to excellent yields. The reaction provides a novel and practical approach to access organic materials of polycyclic aromatic hydrocarbons under mild conditions.     

Superhydrophobic nickel films fabricated by electro and electroless deposition

In this work, a superhydrophobic nickel surface is fabricated by coupling electro and electroless deposition without chemical modification. SEM study reveals that electrodeposited nickel surface is characterized by nanocone arrays and has a contact angle of about 135°. After adding electroless deposition, as the second step, hemispherically topped nickel nanocone arrays are formed which leads to a high contact angle of 153.6°. That is, nickel surface has successfully transformed from hydrophobic to superhydrophobic. This transition is investigated both from the aspects of chemical composition and surface structure and proves the latter is the dominant factor. The present study inspires us to do more research about the creation of rough surfaces and enriches our comprehension about superhydrophobicity.     

Metal-free synthesis of (E)-vinyl sulfones via denitrative coupling reactions of β-nitrostyrenes with sodium sulfinates

Abstract

A practical metal-free procedure for the synthesis of (E)-vinyl sulfones has been developed through the coupling of β-nitrostyrenes with sodium sulfinates under microwave irradiation. This methodology provides a convenient and efficient approach to various (E)-vinyl sulfones from readily available starting materials with excellent regioselectivity. The present oxidative reaction involves an efficient denitrative radical cross-coupling of β-nitrostyrenes with sodium sulfinates via using AcOH as an additive.