中国西北地区沙尘暴的发生规律研究

借助MATLAB软件,根据中国西北地区六个省份1981～2005年沙尘暴发生天数、月平均风速、大风发生天数、月平均气温、月降水量、月平均相对湿度的统计数据,研究中国西北地区沙尘暴的区域分布和时间分布规律及其与气象因子的关系.方差分析结果表明:西北地区沙尘暴危害程度省份差异不显著,不同观测站所在地沙尘暴危害程度的差异显著,不同月份沙尘暴危害程度的差异也显著;聚类分析结果表明:拐子湖等站点所在地受沙尘暴危害最严重,各年4月份受沙尘暴危害最严重,北京地区8月份几乎不发生沙尘暴;相关分析结果表明:西北地区沙尘暴的气候影响因子为月平均风速、月大风发生天数和月相对湿度.由回归分析得到,沙尘暴每月发生天数y随月份t的变化规律为正态分布.研究结果可供有关部门参考.     

临界情况下模糊矩阵对策的性质

讨论临界情况下模糊矩阵对策的性抽，对模型问题各种情况给出了临界值c*的定义，证明了当d(f1,f2)＜ε≤c*时，模糊矩阵对策模型问题关于价值函数f1(x)、f2(x)具有连续依赖性和可调和性。     

Electrochemical Reduction Characteristics of α-Nitronaphthalene inSulfuric Acid Solution

1-Amino-5-naphtholisanimportantintermediateproductfororganicsynthesis'.Itwastraditionallysynthesizedfroma-nityonaphthalenebychemicalmethod.HO:wever,thechemicalmethodneedstwostepsandproducesalargequantityofwastewater,indicatingthehigherenergyconsumptionandpollution.Inthispaper,theelectrochemicalreductionofa-nitronaphthalenetol-amino-5-naphtholwasfirstputforward,theelectrochemicalreductioncharacteristicsofa-nitronaphthalenetol-amino-5-naphtholwerestudiedandthereactionmechanismwasproposedaswell.…     

Efficient Electrocatalytic Reduction of CO2 by Nitrogen-Doped Nanoporous Carbon/Carbon Nanotube Membranes: A Step Towards the Electrochemical CO2 Refinery

Herein we introduce a straightforward, low cost, scalable, and technologically relevant method to manufacture an all-carbon, electroactive, nitrogen-doped nanoporous-carbon/carbon-nanotube composite membrane, dubbed “HNCM/CNT”. The membrane is demonstrated to function as a binder-free, high-performance gas diffusion electrode for the electrocatalytic reduction of CO₂ to formate. The Faradaic efficiency (FE) for the production of formate is 81 %. Furthermore, the robust structural and electrochemical properties of the membrane endow it with excellent long-term stability.     

Improving imprinted shape cavities of molecularly imprinted sol–gel host matrix with minimal relaxation for sensing of creatinine

Journal of Sol-Gel Science and Technology - Molecularly imprinted polymer (MIP) is of great attention in biomimetic recognition systems due to its selective molecular recognition towards any guest...     

Neolignans and Caffeoyl Derivatives from Selaginella moellendorffii

Ten new phenolic compounds including the six neolignans 1 – 3 and 6 – 8 and four caffeoyl derivatives, i.e., myo‐inositol 1‐caffeate ( 9 ), myo‐inositol 6‐caffeate ( 10 ), myo‐inositol 5‐caffeate ( 11 ), and paucine 3′‐β‐D ‐glucopyranoside ( 12 ) were isolated from the whole plants of Selaginella moellendorffii (caffeic acid=3‐(3,4‐dihydroxyphenyl)prop‐2‐enoic acid). Their structures were established by spectroscopic and chemical methods.     

A Shifted Double-Diamond Titania Scaffold

Photonic crystals are expected to be metamaterials because of their potential to control the propagation of light in the linear and nonlinear regimes. Biological single-network, triply periodic constant mean curvature surface structures are considered excellent candidates owing to their large complete band gap. However, the chemical construction of these relevant structures is rare and developing new structures from thermodynamically stable double-network self-organizing systems is challenging. Herein, we reveal that the shifted double-diamond titania scaffold can achieve a complete band gap. The largest (7.71 %) band gap is theoretically obtained by shifting 0.332 c with the dielectric contrast of titania (6.25). A titania scaffold with similar shifted double-diamond structure was fabricated using a reverse core–shell microphase-templating system with an amphiphilic diblock copolymer and a titania source in a mixture of tetrahydrofuran and water, which could result in a 2.05–3.78 % gap.     

Solvatochromic Behavior of Chiral Mesoporous Metal–Organic Frameworks and Their Applications for Sensing Small Molecules and Separating Cationic Dyes

Two anionic metal–organic frameworks (MOFs) with 1D mesoporous tubes ( 1 ) and chiral mesoporous cages ( 2 ) have been rationally constructed by means of a predesigned size‐extended hexatopic ligand, namely, 5,5′,5′′‐(1,3,5‐triazine‐2,4,6‐triyl)tris‐ (azanediyl)triisophthalate (TATAT). Charge neutrality is achieved by protonated dimethylamine cations. Notably, the two MOFs can be used to separate large molecules based on ionic selectivity rather than the size‐exclusion effect so far reported in the literature. Owing to the imino triazine backbone and carboxyl groups of the hexatopic ligand, which provide important host–guest interactions, rare solvatochromic phenomena of 1 and 2 are observed on incorporating acetone and ethanol guests. Furthermore, guest‐dependent luminescence properties of compound 2 were investigated, and the results show that luminescence intensity is significantly enhanced in toluene and benzene, while quenching effects are observed in acetone and ethanol. Thus, compound 2 may be a potential material for luminescent probes.