Stimuli-Responsive Circularly Polarized Organic Ultralong Room Temperature Phosphorescence

Purely organic materials showing room temperature phosphorescence (RTP) and ultralong RTP (OURTP) have recently attracted much attention. However, it is challenging to integrate circularly polarized luminescence (CPL) into RTP/OURTP. Here, we show a strategy to realize CPL-active OURTP (CP-OURTP) by binding an achiral phosphor group directly to the chiral center of an ester chain. Engineering of this flexible chiral chain enables efficient chirality transfer to carbazole aggregates, resulting in strong CP-OURTP with a lifetime of over 0.6 s and dissymmetry factor of 2.3×10⁻³ after the conformation regulation upon photo-activation. The realized CP-OURTP is thus stable at room temperature but can be deactivated quickly at 50 °C to CP-RTP with high CPL stability during the photo-activation/thermal-deactivation cycles. Based on this extraordinary photo/thermal-responsive and highly reversible CP-OURTP/RTP, a CPL-featured lifetime-encrypted combinational logic device has been successfully established.     

Amidation-Dominated Re-Assembly Strategy for Single-Atom Design/Nano-Engineering: Constructing Ni/S/C Nanotubes with Fast and Stable K-Storage

An amidation-dominated re-assembly strategy is developed to prepare uniform single atom Ni/S/C nanotubes. In this re-assembly process, a single-atom design and nano-structured engineering are realized simultaneously. Both the NiO₅ single-atom active centers and nanotube framework endow the Ni/S/C ternary composite with accelerated reaction kinetics for potassium-ion storage. Theoretical calculations and electrochemical studies prove that the atomically dispersed Ni could enhance the convention kinetics and decrease the decomposition energy barrier of the chemically-absorbed small-molecule sulfur in Ni/S/C nanotubes, thus lowering the electrode reaction overpotential and resistance remarkably. The mechanically stable nanotube framework could well accommodate the volume variation during potassiation/depotassiation process. As a result, a high K-storage capacity of 608 mAh g⁻¹ at 100 mA g⁻¹ and stable cycling capacity of 330.6 mAh g⁻¹ at 1000 mA g⁻¹ after 500 cycles are achieved.     

环境科学与工程专业物理化学课程教与学的探讨

物理化学的学习前提是具有良好的高等数学知识基础及较强的逻辑推理能力,因此物理化学普遍被视为最难学的化学学科。本文紧扣金课标准,以环境科学与工程类专业学生为授课对象,基于近年来作者在物理化学教学内容和方法方面的探索,分析物理化学中的教与学中存在的问题及解决方法。     

UV-light irradiation preparation of soybean residue-based hydrogel composite from inorganic/organic hybrids for degradable slow-release N-fertilizer

Research on Chemical Intermediates - Biomass waste, which was the by-product generated along with the production of food, was transformed into high-value constituent in slow-release fertilizers....     

Methanol synthesis from CO2: a DFT investigation on Zn-promoted Cu catalyst

Research on Chemical Intermediates - The reaction steps during methanol synthesis from CO2/H2 are influenced by the type of catalysts such as pure Cu and Zn-decorated Cu. In this study, density...     

The Promotion Effect of NaCl on the Conversion of Xylose to Furfural†

Summary of main observation and conclusion In this work,the promotion effect of NaCl on the conversion of xylose to furfural in H2O was studied.it was found that xylose conversion and furfural yield increased with NaCl concentration.NaCl decreased the pH of the solution providing H+ for the acid catalytic dehydration of xylose.The formation of oligomers was determined by GPC and ESI-MS in the initial stage of reaction,especially at low temperature.Excess NaCl promoted the formation of humins in the late stage of the reaction.NaCl could also change the decomposition route of formic acid.Meanwhile,NaCl had the ability of phase separation.Combining these effects with organic solvent during the reaction could inhibit the formation of humins and increase the yield of furfural.In NaCl-H2O-THF biphasic system without other catalyst,the optimal furfural yield of 76.7% and selectivity of 77.6% were achieved at 463 K in 2 h.     

Imitation of drug metabolism in cell co-culture microcapsule model using a microfluidic chip platform coupled to mass spectrometry

In this work,a multi-functional analysis platform by coupling a microfluidic chip to a mass spectrometry(MS) detector was described.We constructed a three-dimensional tumor-endothelial co-culture model for simulating drug resistance during tumor treatment.On this specially designed integrated platform,the first step was to prepare heterogeneous cell-encapsulated alginate microcapsules for threedimensional co-culture,and the second step was to achieve on-line perfusion culture and continuous drug stimulation on chip.It facilitates cell proliferation analysis and the collection of metabolism medium.After micro solid phase extraction column(SPE) pretreatment,subsequent mass spectrometry could detect drug metabolism.The high activity of two kinds of cells(A549 and HUVEC) shows the biocompatibility of the platform.Paclitaxel was used as a model drug,the distinctions of drug absorption between the mono-culture group and co-culture group were clearly observed by electrospray ionization quadrupole time-of-flight mass spectrometry(ESI-Q-TOF MS).Therefore,the integrated platform has shown promise as a high throughput,low cost for cell metabolism research and drug screening processes.     

A novel Mo-based oxide β-SnMoO_4 as anode for lithium ion battery

Recently,the development of new electrode materials for lithium-ion batteries(LIBs)has received intensive attention.As an important family of inorganic materials,mixed Mo-based transition metal oxides system is focused as anode materials.In the present work,a simple route has been adopted for the synthesis of layered-flake-likeβ-SnMo04 Nano-assemblies,which have been explored as potential anode materials for the first time in lithium-ion battery(LIB).Overall,the current reports on metal molybdate as anode materials are still rarely.As the anode material for LIBs,it was observed that the fabricated anode is capable of delivering a steady state capacity of almost 400 mAh/g up to 300 cycles under the influence of200 mA/g current density.Further,the anode material is suitable for use as a rated capacity anode because of its high current density tolerance.The present study can be further extended for the generation of a wide variety of other novel materials for multidisciplinary energy related applications.     

Enhanced TE properties of Cu@Ag/Bi2Te3 nanocomposites by decoupling electrical and thermal properties

Cu@Ag/Bi2Te3 nanocomposites were prepared for the first time by ultrasonic dispersion-rapid freezedrying method combined with spark plasma sintering(SPS).By changing the content of Cu@Ag nanoparticle,we could modulate the temperature dependent thermoelectric properties.The highest ZT value can be obtained at 450 K for 1 vol%Cu@Ag/Bi2Te3,which is benefited from the decoupling of electrical and thermal properties.With the increase of electrical conductivity,the absolute value of Seebeck coefficient lifts while the thermal conductivity declines.Meanwhile,the average ZT value between 300 K and 475 K was 0.61 for 1 vol%Cu@Ag/Bi2Te3,which is much higher than that of pristine Bi2 Te3.Therefore,the decoupling effect of Cu@Ag nanoparticles incorporation could be a promising method to broaden the application of Bi2Te3 based thermoelectric materials.     

Constructing spin-adiabatic states for the modeling of spin-crossing reactions. I. A shared-orbital implementation

In the modeling of spin-crossing reactions, it has become popular to directly explore the spin-adiabatic surfaces. Specifically, through constructing spin-adiabatic states from a two-state Hamiltonian (with spin-orbit coupling matrix elements) at each geometry, one can readily employ advanced geometry optimization algorithms to acquire a “transition state” structure, where the spin crossing occurs. In this work, we report the implementation of a fully-variational spin-adiabatic approach based on Kohn-Sham density functional theory spin states (sharing the same set of molecular orbitals) and the Breit-Pauli one-electron spin-orbit operator. For three model spin-crossing reactions (predissociation of N₂O, singlet-triplet conversion in CH₂, and CO addition to Fe(CO)₄), the spin-crossing points were obtained. Our results also indicated the Breit-Pauli one-electron spin-orbit coupling can vary significantly along the reaction pathway on the spin-adiabatic energy surface. On the other hand, due to the restriction that low-spin and high-spin states share the same set of molecular orbitals, the acquired spin-adiabatic energy surface shows a cusp (ie, a first-order discontinuity) at the crossing point, which prevents the use of standard geometry optimization algorithms to pinpoint the crossing point. An extension with this restriction removed is being developed to achieve the smoothness of spin-adiabatic surfaces.