基于3,6-二肼基-1,2,4,5-四嗪的两种高氮含能离子盐

本文通过3,6-二肼基-1,2,4,5-四嗪(DHT)分别与高氯酸和硝酸反应得到2种高氮含能离子盐,并通过X-射线单晶衍射技术对它们的结构进行了表征。(DHT)(NO₃)₂(1)属于单斜晶系,C2/c空间群,晶胞参数：a=1.300 0(6) nm,b=0.834 9(3) nm,c=1.018 7(5) nm,β=118.89(5)°,Z=4;(DHT)(ClO₄)₂(2)属于正交晶系,P2₁2₁2空间群,晶胞参数：a=0.980 4(4) nm,b=1.074 7(4) nm,c=0.532 5(2) nm,Z=2。采用DSC和TG-DTG技术研究了这两种含能离子盐的热分解机理,并对这两种含能离子盐的非等温动力学、爆热及感度进行了测试分析。研究表明这两种含能离子盐在敏感型含能材料领域具有潜在的应用前景。     

Preparation,Crystal Structure,and Thermal Decomposition of the Intriguing Five‐coordinated Compound [Cu(IMI)4Cl]Cl (IMI = Imidazole)

The intriguing multi‐ligand compound [Cu(IMI)₄Cl]Cl ( 1 ) with the ligand imidazole (IMI) was synthesized and characterized by elemental analysis and FT‐IR spectroscopy. The crystal structure was determined by X‐ray single crystal diffraction and the crystallographic data showed that the compound belongs to the monoclinic P2₁/n space group [α = 8.847(2) Å, b = 13.210(3) Å, c = 13.870(3) Å, and β = 90.164(3)°]. Furthermore, the Cu^II ion is five‐coordinated by four nitrogen atoms from four imidazole ligands and a chlorine atom. The thermal decomposition mechanism was determined based on differential scanning calorimetry (DSC) and thermogravimetric (TG‐DTG) analysis. The non‐isothermal kinetics parameters were calculated by the Kissinger's method and Ozawa's method, respectively. The energy of combustion, enthalpy of formation, critical temperature of thermal explosion, entropy of activation (ΔS^≠), enthalpy of activation (ΔH^≠), and free energy of activation (ΔG^≠) were measured and calculated.     

Development of an automated dual‐mode supercritical fluid chromatography and reversed‐phase liquid chromatography mass‐directed purification system for small‐molecule drug discovery

We report the development of a dual‐mode mass‐directed supercritical fluid chromatography and reversed‐phase liquid chromatography purification system. The addition of a third pump allows for flexible mobile phase control between the two techniques, and enables operation of either chromatography mode within minutes by activation of a set of switching valves on a single system. Software control, fluidic pathways, interface to the mass spectrometer, and fraction collection have been modified for compatibility between both separation methods. The conditioning solvent and tuning parameters for the mass spectrometer were adjusted to achieve an ideal signal trace in either mode with good linearity (r² > 0.970) over a range of concentrations and minimal noise for accurate peak detection and isolation. The registration success rate is 90% and overall sample recovery for either technique is 80?90%. Combining two orthogonal separation and purification modes in one single system has improved the purification throughput of complex mixtures and has been a valuable, cost‐saving tool in our laboratory.     

单金纳米棒的光散射分析化学:径向比与分析灵敏度的关系

单纳米颗粒作为信号感应单元在化学与生物传感应用中已引起广泛关注.本文通过暗场显微成像(iDFM)研究了不同径向比金纳米棒的光散射性质.将iDFM与扫描电子显微镜(SEM)结合表征种子生长法制备的金纳米棒,结果发现,因局域表面等离子体共振而展示出的红色散射光随单个金纳米棒的径向比增大逐渐红移,且金纳米棒对其周围介质折光率(RI)变化的敏感程度随径向比增大而增大.这一结果对设计高灵敏的生物纳米传感器、提高分析检测的灵敏度具有很好的指导意义.     

Constructing novel red-emitting Ba2Y0.8Eu0.2NbO6:Mn4+ phosphors for multi-type luminescent thermometers and high-security anti-counterfeiting films

To date, luminescent materials have been preferably used for non-contact optical thermometers. In this manner, novel red-emitting Ba₂Y_0.8Eu_0.2NbO₆:Mn⁴⁺ (BYEN:Mn⁴⁺) phosphors were designed for multi-type non-contact luminescent thermometers based on the dual-emission states and temperature-dependent lifetime (TDL) models. In the temperature range of 303–483 K, the sensing sensitivities based on the dual-emission states of (⁵D₀→⁷F₂, ²E_g→⁴A_2g) and (⁵D₀→⁷F₁, ²E_g→⁴A_2g) were estimated. Especially, the maximum absolute sensing sensitivity (S_a) was found to be about 0.1558 K^-1 for the BYEN:0.007Mn⁴⁺ phosphor based on the ⁵D₀→⁷F₁ and ²E_g→⁴A_2g positions. This phosphor also exhibited good relative sensing sensitivity (S_r) (0.0186 K^-1) based on the ⁵D₀→⁷F₂ and ²E_g→⁴A_2g states. Besides, the relative sensing sensitivities (S_R) at ⁵D₀→⁷F₁ and ²E_g→⁴A_2g transitions were estimated to be 0.0034 and 0.0194 K^-1, respectively with the help of the TDL technique. In the light of these results, novel red-emitting Ba₂Y_0.8Eu_0.2NbO₆:Mn⁴⁺ phosphors are expected to be a potentially attractive candidate for applications in multi-type luminescent thermometers. Finally, a novel unique polydimethylsiloxane film exhibiting tricolor-luminescent emissions was introduced and further suggested for high-security anti-counterfeiting.     

Effect of selected dopants on conductivity and moisture stability of Li3PS4 sulfide solid electrolyte: a first-principles study

The first principle computational screening was performed to investigate the effect of selected dopants for Li₃PS₄ sulfide solid electrolyte on its ionic conductivity and stability toward moisture. The results suggest that substitution P⁵⁺ using isovalent cations whose electronegativity (EN) value is closer to the value of S has more significant effects on the ionic conductivity, whereby W⁵⁺ and Sb⁵⁺ can improve most. Similarly, aliovalent cation substitutions with compensating changes in the lithium-ion concentration, particularly those with a lower oxidation state and higher EN, such as Cu²⁺, effectively enhance the lithium-ion conductivity in this structure. For cation dopants, it is found that ionic conductivity improvement of Li₃PS₄ is the synergetic effect of EN and oxidation number of the dopant as well as the material's lattice parameter change. Oxides of the considered cation dopants can also improve the ionic conductivity of the material but have much lower lithium-ion conductivity than the cases of cation dopants. However, the metal oxide dopants, particularly those derived from soft Lewis' acid cations, show a marginal improvement in moisture stability of the Li₃PS₄ electrolyte. The effect of halides and metal halide dopants on the lithium-ion conductivity and moisture stability of Li₃PS₄ electrolyte are also studied. It is found that metal halides are more effective than any other dopants in improving the ionic conductivity of Li₃PS₄.     

Approaches to achieve surface sensitivity in the in situ XAS of electrocatalysts

In situ and operando techniques providing information regarding adsorbate bonding and atomic arrangements on the electrode surface along with pure electrochemical measurements are needed to more fully understand the detailed mechanism of electrocatalytic reactions on high surface areas/nanoparticle electrocatalysts. X-ray adsorption spectroscopy (XAS) is a powerful tool to interrogate the electronic structure and local coordination environment of such electrocatalysts under working conditions, but it should be acknowledged that standard XAS methods are not intrinsically surface sensitive. This review will present recent in situ XAS studies on single-atom, metal, and metal oxide electrocatalysts, highlighting the approaches taken to achieve surface sensitivity by careful designing of the sample under investigation.     

等离子体金属纳米结构在SERS传感及可穿戴应力传感中的应用

等离子体金属(金、银)纳米结构因其特有的理化性能,被广泛应用于表面增强拉曼散射(Surface-enhanced Raman scattering,SERS)传感及可穿戴应力传感领域。其中,SERS是一种应用贵金属纳米材料增强拉曼散射信号的检测技术,该技术灵敏度高、特异性强,已被广泛用于生物医学、环境监测、食品药品检测等领域。随着电子检测技术和柔性电子材料的快速发展,柔性可穿戴传感技术也得到了快速发展,且取得了大量的研究成果。SERS检测技术主要依赖于贵金属纳米增强基底材料,而基于贵金属纳米结构的可穿戴传感元件对人体微应力、微应变的传感具有极高的灵敏度。SERS增强基底材料与可穿戴应力传感元件材料具有互通互用性,将贵金属纳米SERS基底应用于柔性可穿戴式检测,这是SERS检测技术比较新颖的、尚未深入研究的应用领域之一。该文综述了贵金属溶胶纳米结构的材料组成分类以及该类材料在SERS和可穿戴应力传感中的应用,并分析了胶体贵金属纳米结构组成及成分对SERS传感、可穿戴应力传感灵敏度、可重复性及稳定性的影响,最后展望了贵金属胶体纳米结构在SERS传感和柔性可穿戴应用中的发展趋势。     

Synthesis,Characterization of Cr Doped TeO2 Nanostructures and its Application as EGFET pH Sensor

In the present work, Cr doped tellurium dioxide nanostructures (CTO NS)(1 wt %, 6 wt %, 8 wt % and 12 wt %) synthesized by co precipitation method and characterized by CV, UV-Visible, SEM, XRD, XPS spectroscopic analysis. Electron beam deposited thin film of CTO NS having 12 wt % of Cr exhibited EGFET-pH sensitivity of 62.03 mV/pH at 250 °C in buffer solutions of pH 6–12, linearity 0.9345, drift rate of 1.12 mV/h and deviation of 0.01145 as compared with 1 wt %, 6 wt % and 8 wt % of CTO NS.     

Comparative analysis of CR-39 sensitivity for different sets of measurable track parameters

In the present paper the sensitivity V of plastic nuclear track detectors CR-39 to the space radiation, accelerated heavy ions in wide LET range and α-particles is studied. Different approaches for V evaluation are considered and compared. Main attention is given to the method that is appropriate for the measurement of short range heavy secondaries of space radiation. Finally, the experimental verification of the designed V function is carried out via simulation of the secondaries with low energy α-particles in the vicinity of the Bragg peak.