壳层厚度对骨架Fe@HZSM-5核壳催化剂费托合成催化性能的影响

在不同的水热合成时间下,以铁铝合金为铁源和铝源,四丙基氢氧化铵为分子筛的模板剂和抽提合金中的铝的碱,一步制得了以骨架铁为核、不同厚度的HZSM-5分子筛为壳的Raney Fe@HZSM-5催化剂.采用元素分析、氮物理吸附、X射线粉末衍射、氨脱附、扫描电子显微镜等手段,考察了水热时间对催化剂基本物化性质的影响.随着水热时...     

铝锡合金制氢技术研究

采用机械球磨法制备了铝锡系列合金. 水解制氢曲线和XRD结果表明, 添加剂(锌和氢化物)的加入和球磨时间的延长, 有利于金属铝和金属锡的均匀混合和活性一致. 常温下该系列合金与水反应迅速, 氢气产量高. 尤其是球磨10 h的Al-10%Sn-5%Zn-5%MgH2(质量分数)合金, 在10 min内水解反应结束, 氢气产量为785 mL/g, 水解速率为78.5 mL/(min·g).     

纳米稀土磷酸盐(Gd,Y)PO4:Tb的室温固相合成及发光性能

三基色荧光灯用绿色发光材料,其发光效率对总的光通量影响很大[1],因而探索不同体系的绿色发光材料的合成将意义重大.由于Tb3 离子具有较好的特征绿色发射,所以研究铽的不同体系绿粉一直是人们所感兴趣的课题[2].稀土磷酸盐发光材料具有发光亮度高,合成温度适中,色坐标x值大等优点,因而成为当前材料科学的热门[3-5].     

Recent Progress in Biosensors for Detection of Tumor Biomarkers

Cancer is a leading cause of death worldwide, with an increasing mortality rate over the past years. The early detection of cancer contributes to early diagnosis and subsequent treatment. How to detect early cancer has become one of the hot research directions of cancer. Tumor biomarkers, biochemical parameters for reflecting cancer occurrence and progression have caused much attention in cancer early detection. Due to high sensitivity, convenience and low cost, biosensors have been largely developed to detect tumor biomarkers. This review describes the application of various biosensors in detecting tumor markers. Firstly, several typical tumor makers, such as neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), prostate-specific antigen (PSA), squamous cell carcinoma antigen (SCCA), carbohydrate, antigen19-9 (CA19-9) and tumor suppressor p53 (TP53), which may be helpful for early cancer detection in the clinic, are briefly described. Then, various biosensors, mainly focusing on electrochemical biosensors, optical biosensors, photoelectrochemical biosensors, piezoelectric biosensors and aptamer sensors, are discussed. Specifically, the operation principles of biosensors, nanomaterials used in biosensors and the application of biosensors in tumor marker detection have been comprehensively reviewed and provided. Lastly, the challenges and prospects for developing effective biosensors for early cancer diagnosis are discussed.     

Study on the Structure of a Mixed KCl and K2SO4 Aqueous Solution Using a Modified X-ray Scattering Device,Raman Spectroscopy,and Molecular Dynamics Simulation

The microstructure of a mixed KCl and K₂SO₄ aqueous solution was studied using X-ray scattering (XRS), Raman spectroscopy, and molecular dynamics simulation (MD). Reduced structure functions [F(Q)], reduced pair distribution functions [G(r)], Raman spectrum, and pair distribution functions (PDF) were obtained. The XRS results show that the main peak (r = 2.81 Å) of G(r) shifted to the right of the axis (r = 3.15 Å) with increased KCl and decreased K₂SO₄. The main peak was at r = 3.15 Å when the KCl concentration was 26.00% and the K₂SO₄ concentration was 0.00%. It is speculated that this phenomenon was caused by the main interaction changing, from K-O_W (r = 2.80 Å) and O_W-O_W (r = 2.80 Å), to Cl⁻-O_W (r = 3.14 Å) and K⁺-Cl⁻ (r = 3.15 Å). According to the trend of the hydrogen bond structure in the Raman spectrum, when the concentration of KCl was high and K₂SO₄ was low, the destruction of the tetrahedral hydrogen bond network in the solution was more serious. This shows that the destruction strength of the anion to the hydrogen bond network structure in solution was Cl⁻ > SO₄²⁻. In the MD simulations, the coordination number of O_W-O_W decreased with increasing KCl concentration, indicating that the tetrahedral hydrogen bond network was severely disrupted, which confirmed the results of the Raman spectroscopy. The hydration radius and coordination number of SO₄²⁻ in the mixed solution were larger than Cl⁻, thus revealing the reason why the solubility of KCl in water was greater than that of K₂SO₄ at room temperature.     

The Crucial Role of Charge Accumulation and Spin Polarization in Activating Carbon-Based Catalysts for Electrocatalytic Nitrogen Reduction

Cost-effective carbon-based catalysts are promising for catalyzing the electrochemical N₂ reduction reaction (NRR). However, the activity origin of carbon-based catalysts towards NRR remains unclear, and regularities and rules for the rational design of carbon-based NRR electrocatalysts are still lacking. Based on a combination of theoretical calculations and experimental observations, chalcogen/oxygen group element (O, S, Se, Te) doped carbon materials were systematically evaluated as potential NRR catalysts. Heteroatom-doping-induced charge accumulation facilitates N₂ adsorption on carbon atoms and spin polarization boosts the potential-determining step of the first protonation to form *NNH. Te-doped and Se-doped C catalysts exhibited high intrinsic NRR activity that is superior to most metal-based catalysts. Establishing the correlation between the electronic structure and NRR performance for carbon-based materials paves the pathway for their NRR application.     

Electrochemical Oxidative C—H Sulfenylation of Imidazopyridines with Hydrogen Evolution

Selective oxidative C—H sulfenylation of imidazopyridine heterocycles is achieved using an undivided electrolytic cell. The reaction avoids the use of stoichiometric amount of external chemical oxidant and produces hydrogen gas as the only byproduct. Both aryl and aliphatic thiols demonstrate good reactivity for C—S bond formation.     

Open tubular capillary electrochromatography with block co-polymer coating for separation of β-lactam antibiotics

Unique block co-polymer P(MAn-St-NIPAm) has been successfully synthesized by reversible addition fragmentation chain transfer radical polymerization protocol. Based on the tunable hydrophobic/hydrophilic properties of the block co-polymer, a new open tubular capillary electrochromatography (OT-CEC) system has been constructed with the prepared block co-polymer as the coating and applied in analysis of β-lactam antibiotics in serum samples.     

An Inverse Design Method for Non-uniform Flow Inlet with a Given Shock Wave

Acta Mathematicae Applicatae Sinica, English Series - For the hypersonic inlet and fore-body integrated design, the non-uniform incoming flow generated by the fore-body will bring a relatively big...     

Engel Condition and p-nilpotency of Finite Groups

Let G be a finite group, and let P be a Sylow p-subgroup of G. Under the hypothesis that NG(P) is p-nilpotent, we provide some conditions to give a p-nilpotency criterion of finite groups by Engel condition, which improves some recent results.