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排序方式: 共有890条查询结果,搜索用时 15 毫秒
881.
882.
Dr. Pankaj Sharma Dr. Monika Sharma Dr. Malcolm Dearg Dr. Martin Wilding Dr. Thomas J. A. Slater Prof. C. Richard A. Catlow 《Angewandte Chemie (International ed. in English)》2023,62(20):e202301239
Despite extensive efforts to develop high-performance H2 evolution catalysts, this remains a major challenge. Here, we demonstrate the use of Cd/Pt precursor solutions for significant photocatalytic H2 production (154.7 mmol g−1 h−1), removing the need for a pre-synthesized photocatalyst. In addition, we also report simultaneous in situ synthesis of Pt single-atoms anchored CdS nanoparticles (PtSA-CdSIS) during photoirradiation. The highly dispersed in situ incorporation of extensive Pt single atoms on CdSIS enables the enhancement of active sites and suppresses charge recombination, which results in exceptionally high solar-to-hydrogen conversion efficiency of ≈1 % and an apparent quantum yield of over 91 % (365 nm) for H2 production. Our work not only provides a promising strategy for maximising H2 production efficiency but also provides a green process for H2 production and the synthesis of highly photoactive PtSA-CdSIS nanoparticles. 相似文献
883.
Dr. Jingyu Guo Junben Huang Abudukadi Tudi Prof. Xueling Hou Dr. Shujuan Han Prof. Zhihua Yang Prof. Shilie Pan 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304238
It is important to establish and clarify the relationship between stereochemically active lone pairs and birefringence, since it is one of the significantly effective routes to explore birefringent crystals by introducing Sn-centered polyhedra with stereochemically active lone pairs. Herein, four tin(II)-based ternary halides A3SnCl5 and ASn2Cl5 (A=NH4 and Rb) have been synthesized successfully. The experimental birefringence of Rb3SnCl5 and RbSn2Cl5 is larger than or equal to 0.046 and 0.123@546 nm, respectively. Through investigating the alkali or alkaline-earth metal tin(II)-based ternary halides, the structure-performance relationship has been concluded between stereochemically active lone pairs and optical anisotropy. It is beneficial to the analysis and prediction of birefringence in tin-based halides and provides a guide for exploring tin(II)-based optoelectronic functional materials. 相似文献
884.
In this work, we consider a frustrated two-leg spin-1/2 ladder composed of Heisenberg ferromagnetic and antiferromagnetic spin-1/2 chains, and nearest spins from different legs interact via Heisenberg type rung exchange interactions that can be either ferromagnetic or antiferromagnetic in nature. The competing exchange interactions in the system lead to five different quantum phases like ferromagnetic, non-collinear ferrimagnetic (NCF), , antiferromagnetic and dimer phases. The quantum phase diagram is constructed for the Heisenberg spin-1/2 model and the phases are characterized using the correlation functions which are calculated by the density matrix renormalization group method. We also analyze the stability of phase and calculate the pitch angle in the NCF phase. 相似文献
885.
《印度化学会志》2023,100(3):100933
The electrochemical machining is a non-conventional machining process based on the electrolysis principle. It is used to machine various features on conducting engineering materials with the required accuracy and precision. So an attempt has been made to machine micro-holes on a 300 μm thick copper plate as an anode and a hollow stainless steel tool electrode of 250 μm diameter as the cathode. The machining operation is performed on the in-house developed micro-ECM experimental setup with controlled machining parameters voltage, concentration, and duty factor varied in three levels. A full factorial experimental plan is used to study the output responses material removal rate (MRR), radial overcut (ROC), circularity, and taper angle (TA). Later an adaptive neuro-fuzzy inference system (ANFIS) model has been developed and shown the effectiveness of the developed model in the paper. The Sugeno fuzzy model has been used in ANFIS to generate the fuzzy rules required for the model. Out of 27 experiments, 22 machining data are used for training the model, and the remaining 5 machining data are used for testing the developed model. The average error observed between the ANFIS predicted values and experimental values of MRR is 12.56%, circularity is 43.09%, ROC is 13%, and TA is 27.53%, respectively. 相似文献
886.
Sakshi Yadav Schmid Kacper Lachowski Huat Thart Chiang Lilo Pozzo Jim De Yoreo Shuai Zhang 《Angewandte Chemie (International ed. in English)》2023,62(48):e202309725
Biomolecular self-assembly of hierarchical materials is a precise and adaptable bottom-up approach to synthesizing across scales with considerable energy, health, environment, sustainability, and information technology applications. To achieve desired functions in biomaterials, it is essential to directly observe assembly dynamics and structural evolutions that reflect the underlying energy landscape and the assembly mechanism. This review will summarize the current understanding of biomolecular assembly mechanisms based on in situ characterization and discuss the broader significance and achievements of newly gained insights. In addition, we will also introduce how emerging deep learning/machine learning-based approaches, multiparametric characterization, and high-throughput methods can boost the development of biomolecular self-assembly. The objective of this review is to accelerate the development of in situ characterization approaches for biomolecular self-assembly and to inspire the next generation of biomimetic materials. 相似文献
887.
《Arabian Journal of Chemistry》2023,16(3):104527
Shexiang Xintongning tablet (SXXTN) is a traditional Chinese medicine (TCM) preparation for the treatment of coronary heart disease (CHD) angina pectoris. However, due to the complexity of the compounds in SXXTN, the active chemical components responsible for the therapeutic effect are still ambiguous. The purpose of our study was to characterize the chemical profile of SXXTN and quantify the representative chemicals. The high-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-QTOF MS) method and gas chromatograph coupled with mass spectrometry (GC–MS) method were utilized to identify the chemical constituents of SXXTN. A total of 140 compounds including alkaloids, ginsenosides, organic acids, esters, triterpenes, phthalides and amino acid were identified in accordance with their retention times, accurate masses and characteristic MS/MS fragment patterns. Forty-four volatile components were characterized by GC–MS through NIST database matching. In the further research of quantitative analysis, 40 non-volatile compounds and 17 volatile compounds were determined and successfully applied for detecting in 7 batches of SXXTN samples by high performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (HPLC-QQQ MS) and gas chromatograph coupled with triple-quadrupole tandem mass spectrometry (GC-QQQ MS) in multiple reaction monitoring (MRM) mode, respectively. The quantitative methods were verified in linearity, precision, repeatability stability and recovery. The above results indicated that the established method was practical and reliable for synthetical quality evaluation of SXXTN. In addition, our study might supplement the chemical evidence for disclosing the material basis of its therapeutic effects. 相似文献
888.
889.
Dr. Emmanuel Picheau Dr. Ferdinand Hof Dr. Sara Amar Dr. Alain Derré Dr. Alain Pénicaud 《Angewandte Chemie (International ed. in English)》2023,62(20):e202303060
External diffusion may be exploited as a tool to purify materials in a way thought to be inaccessible from a chemical reactivity point of view. A mixture of two carbonaceous materials, graphite and carbon black, are thermally oxidized in either i) outside total diffusion-limited regime or ii) total diffusion-limited regime. Depending on the treatment applied it is possible to purify either graphite, a trivial task, or carbon black, a task thought impossible. Introducing geometrical selectivity, controlled total diffusion-limited chemistry exceeds by far the field of carbon materials and can be used as an engineering tool for many materials purification, original synthesis, or to introduce asymmetry in a system. Several examples for direct applications of the findings are mentioned. 相似文献
890.
Kyungsene Lee Brandon Davis Xuelin Wang Shubham Mirg Connie Wen Dr. Lidya Abune Dr. Benjamin E. Peterson Dr. Li Han Haoyang Chen Prof. Hongjun Wang Prof. Spencer E. Szczesny Prof. Yuguo Lei Prof. Sri-Rajasekhar Kothapalli Prof. Yong Wang 《Angewandte Chemie (International ed. in English)》2023,62(31):e202306583
Cell encapsulation has been studied for various applications ranging from cell transplantation to biological production. However, current encapsulation technologies focus on cell protection rather than cell regulation that is essential to most if not all cell-based applications. Here we report a method for cell nanoencapsulation and regulation using an ultrathin biomimetic extracellular matrix as a cell nanocapsule to carry nanoparticles (CN2). This method allows high-capacity nanoparticle retention at the vicinity of cell surfaces. The encapsulated cells maintain high viability and normal metabolism. When gold nanoparticles (AuNPs) are used as a model to decorate the nanocapsule, light irradiation transiently increases the temperature, leading to the activation of the heat shock protein 70 (HSP70) promoter and the regulation of reporter gene expression. As the biomimetic nanocapsule can be decorated with any or multiple NPs, CN2 is a promising platform for advancing cell-based applications. 相似文献