Novel CaCO3/g-C3N4 composites with enhanced charge separation and photocatalytic activity

A novel CaCO₃/graphitic carbon nitride (g-C₃N₄) photocatalyst was synthesized for the first time via a facile calcination method using CaCO₃ and melamine as precursors. The as-prepared samples were characterized using various techniques, such as scanning and transmission electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller analysis, as well as Fourier-transform infrared, X-ray photoelectron, photoluminescence, and UV–vis diffuse reflectance spectroscopy. The results of the experiments confirm the successful coupling of CaCO₃ to g-C₃N₄. The photocatalytic activity of the synthesized CaCO₃/g-C₃N₄ composites was evaluated by assessing their performance in the photocatalytic degradation of crystal violet (CV) in water under visible light irradiation. The analysis shows that CaCO₃/g-C₃N₄ exhibits higher photocatalytic activity towards CV degradation (76.0%) than pristine g-C₃N₄ (21.6%) and CaCO₃ (23.2%). Radical trapping and electron spin resonance experiments show that hydroxyl radicals (OH) and holes (h⁺) are the key reactive species in the photocatalytic process. The enhanced photocatalytic activity of the composite is mainly attributed to the efficient separation rate of electron-hole pairs achieved through the incorporation of CaCO₃.     

生物法与化学法制备硫酸软骨素

硫酸软骨素（ChS）是一种天然的酸性黏多糖,生物活性多样,在医学、生物、制药、食品、化妆品和材料等领域均有广泛应用,特别是在治愈骨关节病上具有颇为理想的效果。本文系统地总结了有关硫酸软骨素及其类似物的生物与化学制备方法的研究进展,如高产微生物菌株筛选与改良,培养条件优化与调控,汇聚式合成策略构建,经济易得的起始物原料等,并指出制备硫酸软骨素中存在的问题以及发展方向。     

离子液体辅助溶胶-凝胶法制备ZnO:Al透明导电薄膜及其光电性能研究

采用溶胶-凝胶法,以离子液体为辅助溶剂,在玻璃衬底上制备了ZnO:Al(ZAO)薄膜.通过X-射线衍射(XRD)、场发射扫描电镜(FE-SEM)、紫外-可见分光光度计(UV-Vis)和霍尔效应等测试手段,分析了不同Al掺杂浓度ZAO薄膜的微观结构、光学和电学性能.结果表明,所制备的薄膜为非(002)取向的多晶膜.随着Al离子掺杂浓度的提高,薄膜的(002)晶面取向增强,晶粒逐渐由片状向球形转变,电阻率先降低后升高.进一步研究发现,在还原气氛NH3下退火可显著降低薄膜的电阻率,Al掺杂浓度为1 mol;时,薄膜电阻率达到4.7×10-2Ω·cm,可见光透过率平均在80;以上.     

价值引领融入“无机化学与化学分析”的课程思政建设

将课程思政应用到"无机化学和化学分析"教学中,更好发挥其价值引领作用。开展课程思政建设,应做到守正与创新。本文以价值引领为切入点,介绍如何将思想政治教育有机融入课程内容设置和课堂讲授等环节,力求培养学生的家国情怀、国际视野、法治意识、生态意识、工程伦理、人文关怀等科学素养,深入践行立德树人,提高本科教学质量。     

电子自旋共振作为探针研究卤代溶剂的专属性效应

4-羟基-2,2,6,6-四甲基哌啶-1-氧自由基(4-OH-TEMPO)电子自旋共振的超精细耦合常数AN与溶剂极性的微观反应常数ET(30)和溶剂受体数AN呈现线性正相关. 并且在介电常数或偶极矩接近时, 含卤溶剂中超精细耦合常数AN普遍偏高. 除了一般的溶剂效应外, 在含卤溶剂中超精细耦合常数AN偏大的原因与专属性的卤键作用有关. 理论计算结果辅助印证了这一结论.     

染料分子对硫纳米微粒共振散射光谱的影响

在聚丙烯酰胺存在下液相硫纳米微粒在 470nm处产生 1个强共振散射峰 ;在可见光范围内无吸收峰且吸收值较小。硫微粒质量浓度在 0 0 5～ 1 0mg/L范围内与I4 70nm间有良好线性关系。研究了乙醇、丙酮 ,以及溴酚蓝、溴甲基紫、结晶紫、亮绿等有机染料对硫纳米微粒共振散射的影响。结果发现 ,染料分子吸收是产生共振散射峰的一个重要原因 ;随着染料分子非辐射吸收值的增大 ,硫纳米微粒共振散射光强度降低。实验证明 ,溴酚蓝浓度在 0～ 1 0× 10 -5mol/L范围内 ,在溴酚蓝最大吸收波长 5 90nm处的ΔI590nm与溴酚蓝浓度呈线性关系。     

Crystal Structure and Characterization of a Large Polyoxotungstate (NH4)21{La(H2O)5[Ni(H2O)]2As4W40O140}·53H2O

The heteropolytungstate (NH4)₂₁{La(H₂O)₅[Ni(H₂O)]₂As₄W₄₀O₁₄₀}·53H₂O is obtained by the reaction of Na₂₇[NaAs₄W₄₀O₁₄₀]· 60H₂O with NiCl₂·6H₂O, La(NO₃)₃·6H₂O and NH₄Cl at pH‐4.5. The structure and chemical composition are determined by X‐ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are a = 1.9551(3) nm, b = 2.4156(4) nm, c= 3.7068(6) nm, β = 91.505(3)°, V = 17.500 (5) nm³, monoclinic crystal system with space group P2₁/n, Z = 4, R₁ = 0.0573, wR₂ = 0.0717 [I >2<s?(I)], R₁, = 0.2463 and wR₂ = 0.1199 (all data). [La(H₂O)₅] {Ni(H₂O)}₂AS₄W₄₀O₁₄₀ has C₂, symmetry. IR spectra of the ligand [NaAs₄W₄₀O₁₄₀]^27‐ and its three complexes were discussed.     

PARADOXICAL EFFECT OF A GnRH AGONIST ON STEROIDOGENESIS IN CULTURED MONKEY GRANULOSA CELLS

In this study we demonstrate: (i) The GnRH agonist exerts a direct dose-dependet stimulative effect on the aromatase activity and progesterone production in cultured monkey granulosa cells; (ii)the stimulative effect on steroidogenesis can be completely blocked by concomitant treatment with a GnRH antagonist, suggesting that the actions of GnRH are mediated through stringent stereospecific recongnition sites; (iii) in addition to the stimulative effect, the GnRH agonist in the presence of gonadotropins also exerts an inhibitory effect, even though the peptide by itself is more effective in the stimulation of steroidogenesis, and the stimulation of gonadotropin on steroidogenesis could be gradually restored by decreasing the concentration of the GnRH agonist in the culture; and (iv) paradoxical effect can also be observed in the presence of cAMP-inducing agents, suggesting that the inhibitory action of the peptide on gonadotropin-induced steroidogenesis is localized at a step distal to the stringent reco     

强色指数的一个新的上界

给出了图的强色指数的一个新的上界，并指出几类恰好达到该上界的图，从而改进了Erodoes和Nesetri的强色指数猜想，在某种意义上证明了这个猜想。