Simultaneous Delamination and Rutile Formation on the Surface of Ti3C2Tx MXene for Copper Adsorption

In this work, we studied the formation of the rutile phase of titanium dioxide (TiO₂) on delaminated MXene (d‐Ti₃C₂T_x) flakes by the reaction of Ti₃C₂T_x with amino acids in water. Three types of amino acids with varied side‐chain polarity were used to delaminate Ti₃C₂T_x. d‐Ti₃C₂T_x flakes formed stable colloidal solutions due to the negative surface charges of chemisorbed amino acids on the d‐Ti₃C₂T_x. Rutile formed on d‐Ti₃C₂T_x at room temperature upon the intercalation of aromatic amino acids and subsequent sonication of the solution, while flakes intercalated with aliphatic amino acids did not oxidize. X‐Ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy revealed the nanosize rutile formation on the surface of Ti₃C₂T_x flakes. The XPS results indicated the surface functionalization of histidine on d‐Ti₃C₂T_x flakes. As‐synthesized histidine functionalized rutile TiO₂@d‐Ti₃C₂T_x hybrid was used for adsorption of Cu²⁺ ions from aqueous solution with a maximum uptake of 95 mg g^?1.     

Reduction of elemental selenium by samarium diiodide: Selective synthesis of diorganyl selenides and diselenides

The reduction of elemental selenium by samarium diiodide led to selective formation of selenolate anion species (Se²⁻ and Se₂²⁻), the alkylation of which provided dialkyl selenides and diselenides, respectively, in excellent yields.     

NMR studies on the ligand exchange reactions between diaryl tellurides and phenyllithium: Detection of hypervalent triaryl tellurium ate complexes

Diaryl tellurides undergo rapid ligand exchange and disproportionation reactions on treatment with phenyllithium at −78°C. Triarylteliuranes [10-Te-3(C₃)]⁻ Li⁺ were identified as discrete intermediates during the reactions by ¹²⁵Te, ¹H, ¹³C, and CH-COSY NMR studies.     

Some novel photosensitive diacetylene diurethanes and their mixtures in common polymers

Some new octa-3,5-diynylene diurethanes were prepared using 3-butyn-1-ol, and all were found to be highly light-sensitive and to undergo topochemical polymerization on exposure to irradiation. The di-n-octyldiurethane was mixed with vinyl polymers such as poly(vinyl acetate) and poly(N,N-dimethylamino-ethyl methacrylate) and the mixtures were made into thin films by spin coating. The films were then irradiated by an electron beam to polymerize the diacetylene. The purple films thus obtained showed third-order nonlinear susceptibility, χ⁽³⁾, of the order of 10⁻¹⁰–10⁻¹¹ e.s.u.     

反应离子刻蚀ZnTe的THz辐射和探测研究

运用电光采样技术揭示了反应离子刻蚀（RIE）ZnTe晶体表面THz辐射的光学整流产生机制， 观察到0.25 ps的THz场分布.通过比较刻蚀前后以及不同刻蚀条件下ZnTe样品在不同激发功 率下的THz辐射强度，发现由于反应离子刻蚀破坏了ZnTe样品表面的有序性，晶体的电光系 数随射频功率的增加而减小.借助于计算不同刻蚀条件下ZnTe晶体的频率响应函数，分析了 随射频功率增加ZnTe晶体响应频谱展宽的现象. 关键词： THz辐射 反应离子刻蚀 ZnTe     

Dose-dependent inhibition of ultrasound-induced cell killing and free radical production by carbon dioxide

Previous studies have shown that if a solution for cell suspension is saturated with CO(2), ultrasound-induced in vitro cell killing and free-radical production are inhibited. However, the dose dependency of this observation has not been explored. Here, we used NaHCO(3) and HCl to produce a predictable concentration of CO(2) within the culture medium. Using 1 MHz continuous wave 4 W/cm(2) ultrasound, we sonicated U937 cells suspension for 1 min at 37 degrees C with CO(2) at different concentrations. At 2 mM, reduced cell killing was observed that further decreased with increasing CO(2) concentration until 100% protection was attained at 20 mM. Ultrasound-induced free-radical production was significantly decreased at 1 mM and became undetectable at 2 mM CO(2). This finding shows that CO(2)-mediated inhibition is concentration dependent and that the threshold for free-radical production is one order of magnitude higher than the threshold for cell killing induced by ultrasound. In addition, it also cautions researchers when adding acids and acid-based agents to a culture medium, which almost always contains NaHCO(3), in experiments related to the bioeffects of ultrasound.     

Hydrothermal formation of tobermorite studied by in situ X‐ray diffraction under autoclave condition

Hydrothermal formation of tobermorite from a pre‐cured cake has been investigated by transmission X‐ray diffraction (XRD) using high‐energy X‐rays from a synchrotron radiation source in combination with a newly designed autoclave cell. The autoclave cell has a large and thin beryllium window for wide‐angle X‐ray diffraction; nevertheless, it withstands a steam pressure of more than 1.2 MPa, which enables in situ XRD measurements in a temperature range of 373 to 463 K under a saturated steam pressure. Formation and/or decomposition of several components has been successfully observed during 7.5 h of reaction time. From the intensity changes of the intermediate materials, namely non‐crystalline C–S–H and hydroxylellestadite, two pathways for tobermorite formation have been confirmed. Thus, the newly developed autoclave cell can be used for the analyses of reaction mechanisms under specific atmospheres and temperatures.