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摘要:A series of novel coumarin-stilbenes hybrids called 3-arylcoumarins were synthesized via Perkin reaction and evaluated as potential antitumor *** results showed that some compounds exhibited in vitro activity against KB,KV,MCF-7,MCF-7/ ADR cell lines to some *** 3a showed remarkable effect against KB tumor cells with an IC50 value of 5.18μmol/L.
摘要:The metallurgical properties of the CaO–SiO_(2)–Al_(2)O_(3)–4.6wt%Mg O–Fe_(2)O_(3)slag system,formed by the co-treatment process of spent automotive catalyst(SAC)and copper-bearing electroplating sludge(CBES),were studied systematically in this *** slag structure,melting temperature,and viscous characteristics were investigated by Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,Fact Sage calculation,and viscosity *** results show that the increase of Fe_(2)O_(3)content(3.8wt%–16.6wt%),the mass ratio of CaO/SiO_(2)(m(CaO)/m(SiO_(2)),0.5–1.3),and the mass ratio of SiO_(2)/Al_(2)O_(3)(m(SiO_(2))/m(Al_(2)O_(3)),1.0–5.0)can promote the depolymerization of silicate network,and the presence of a large amount of Fe_(2)O_(3)in form of tetrahedral and octahedral units ensures the charge compensation of Al^(3+)ions and makes Al_(2)O_(3)only behave as an acid *** calculation and viscosity measurements show that with the increase of Fe_(2)O_(3)content,m(Ca O)/m(SiO_(2)),and m(SiO_(2))/m(Al_(2)O_(3)),the depolymerization of silicate network structure and low-melting-point phase transformation first occur within the slag,leading to the decrease in melting point and viscosity of the slag,while further increase causes the formation of high-melting-point phase and a resultant re-increase in viscosity and melting *** on experimental analysis,the preferred slag composition with low polymerization degree,viscosity,and melting point is as follows:Fe_(2)O_(3)content of 10.2wt%–13.4wt%,m(CaO)/m(SiO_(2))of 0.7–0.9 and m(SiO_(2))/m(Al_(2)O_(3))of 3.0–*** work provides a theoretical support for slag design in co-smelting process of SAC and CBES.
摘要:氧化锆(ZrO_(2))陶瓷具有出色的机械性能,但其应用受到低热导率(Thermal Conductivity,TC)的限制。本研究设计并通过微波烧结制备了高热导率氧化锆-氮化铝(AlN)复合陶瓷,优化制备条件后,抑制了两种物质之间的反应,获得了致密的复合陶瓷(相对密度>99%),详细研究了该复合陶瓷的组织演变、热学性能和力学性能。研究结果表明,随着AlN含量的增加,复合陶瓷的室温下热导率、热扩散系数和热容增加,分别达到41.3 W/(m·K)、15.2 mm^(2)/s和0.6 J/(g·K)。这种具有高热导率和抗热震性的ZrO_(2)-AlN复合复合陶瓷在能源系统的高温热交换材料领域具有广阔的应用前景。
摘要:基于密度泛函理论(DFT)的第一原理方法计算了四方相和立方相中2种不同的Li_(7)La_(3)Zr_(2)O_(12)(LLZO)固体电解质材料的能带结构,晶格参数,态密度和成键特性。基于理论计算结果,通过电子结构特性解释了四面体相的离子电导率低于立方相的离子电导率的原因。基于LLZO的第一性原理计算,设计了2种晶体结构的LLZO材料,并通过高温固相法制备并分析了不同烧结时间的LLZO颗粒的性能。探索了合成工艺参数对Li_(7)La_(3)Zr_(2)O_(12)性能的影响。立方晶Li_(7)La_(3)Zr_(2)O_(12)(C-LLZO)的平均晶格大小为a=b=c=1.302 246 nm,而四方Li_(7)La_(3)Zr_(2)O_(12)(T-LLZO)的平均晶格大小为a=b=1.313 064 nm,c=1.266 024 nm。在1000℃下烧结12 h的C-LLZO为纯立方相,在室温(25℃)下最大离子电导率为9.8×10^(-5) S·cm^(-1)。T-LLZO在室温(25℃)下的离子电导率为5.96×10^(-8) S·cm^(-1),在800℃下烧结6 h具有纯的四方相结构,与计算结果基本吻合。
摘要:The ability to detect conspecific's distress is crucial for animal survival. In rodent models, observational fear (OF) occurs when one animal perceives another fear related negative emotions, which may model certain behaviors caused by witnessing traumatic experiences in humans. Anterior cingulate cortex (ACC) has been showed to play a crucial role in OF. However, cellular and neural circuit basis relating to ACC governing OF is poorly understood. Here, we used Designer Receptor Exclusively Activated by a Designer Drug (DREADD) system to investigate the cell type specific circuit mechanism of ACC in OF. Firstly, inhibitory hM4D (Gi) designer receptor together with clozapine N-oxide (CNO) injection was applied to inactivate ACC neurons in the observer mice. We found that, chemogenetic inhibition of ACC resulted in a decreased freezing response in the observer mice. Next, combining PV-ires-Cre mice and Cre-dependent DREADD system, we selectively targeted the ACC parvalbumin (PV) interneurons with the excitatory hM3D (Gq) designer receptor. Activation of ACC PV interneurons following CNO injection reduced freezing response in the observer mice, while had no effect on freezing response in the demon- strator mice. Finally, monosynaptic rabies retrograde tracing revealed that ACC PV interneurons receive inputs from the mediodorsal thalamic nucleus (MD) and the ventromedial thalamic nucleus (VM), both known for their roles in OF. Taken together, these findings reveal that ACC activation is important for OF, during which PV interneurons in ACC play an important regulatory role. Abnormal function of ACC PV interneurons might contribute to the pathology of empathy- deficits related diseases, such as autism and schizoohrenia.
摘要:In the present study, ultrasonic extraction technique (UET) is used to improve the yield of polysaccharides from Lami- naria japonica (LJPs). And their antioxidative as well as glycosidase inhibitory activities are investigated. Box-Behnken design (BBD) combined with response surface methodology (RSM) is applied to optimize ultrasonic extraction for polysaccharides. The optimized conditions are obtained as extraction time at 54 min, ultrasonic power at 1050 W, extraction temperature at 80℃ and ratio of material to solvent at 1:50 (g mL-1). Under these optimal ultrasonic extraction conditions, an actual experimental yield (5.75% + 0.3%) is close to the predicted result (5.67%) with no significant difference (P〉0.05). Vitro antioxidative and glycosidase inhibitory activities tests indicate that the crude polysaccharides (LJP) and two major ethanol precipitated fractions (LJP1 and LJP2) are in a concentration-dependent manner. LJP2 (30%-60% ethanol precipitated polysaccharides) possesses the strongest α-glucosidase in- hibitory activity and moderate scavenging activity against hydroxyl radicals (66.09% ±2.19%, 3.0 mg mL-l). Also, the inhibitory activity against a-glucosidase (59.08% ± 3.79%, 5.0 mg mL-1) is close to that of acarbose (63.99% ± 3.27%, 5.0 mg mL-l). LJP 1 (30% ethanol precipitated polysaccharides) exhibits the strongest scavenging activity against hydroxyl radicals (99.80%q-0.00%, 3.0mg mL-1) and moderate a-glucosidase inhibitory activity (47.76%± 1.92%, 5.0 mgmL-1). LJP shows the most remarkable DPPH scav- enging activity (66.20%±0.11%, 5.0mgmL-1) but weakest a-glucosidase inhibitory activity (37.77%±1.30%, 5.0mgmL-1). How- ever, all these LJPs exert weak inhibitory effects against a-amylase. These results show that UET is an effective method for extract- ing bioactive polysaccharides from seaweed materials. LJP 1 and LJP2 can be developed as a potential ingredient in hypoglycemic agents or functional food for the management of diabetes. This study provi
摘要:Recently, the power conversion efficiencies(PCEs) of all-polymer solar cells(all-PSCs) have increased rapidly. To further increase the PCE of all-PSCs, it is necessary to create new donor polymers matching the polymer acceptors. In this paper, we synthesize a new quinoxaline-based polymer donor PBQ8 with n-octyl side chain on the quinoxaline unit, which possesses the same skeleton structure to the previously reported PBQ5(with isooctyl side chain). The effects of alkyl side chains on the physicochemical properties of the polymer donor were investigated. In comparison with PBQ5, PBQ8 exhibits stronger intermolecular interactions and better molecular packing. When blending with polymer acceptor PY-IT, the PBQ8:PY-IT based devices demonstrated a higher PCE value of 17.04%, which is one of the highest PCEs occurred in the all-PSCs. And the PBQ5:PY-IT(PCE 15.56%, Voc0.907 V, FF 69.72%, and Jsc24.60 m A cm^(-2)) is much lower. The PBQ8:PY-IT blend displayed more efficient exciton dissociation, better molecular stacking properties, preferable phase separation and higher mobility. These indicate that as an effective method, side chain engineering can improve the efficiency of the all-PSCs.
摘要:Dissociative adsorption of HCl on Au(111)has become one of unsolved puzzles in surface *** tremendous efforts in the past years,varioustheoretical models still greatly overestimate the zero-coverage initial sticking probabilities(So).To find the origin of the large experiment-theory discrepancy,we have revisited the dissociative adsorption of HCl on Au(111)with a newly designed molecular beam-surface *** zero-coverage So derived from Cl-coverage measurements with varying HCl doses agree well with previous ***,we notice a sharp change of the coverage/dose slope with the HCl dosage at the low coverage regime,which may result in some uncertainties to the fitted So *** seems consistent with a coverage-dependence of the dissociation barrier predicted by density functional theory at low *** results reveal the potential inconsistency of utilizing simulations with finite coverage to compare against experimental data with zero coverage in this system,and provide guidance for improving both experiment and theory in this regard.
摘要:Splitting water under large current density is essential for efficient large-scale production and commercial utilization of ***,the performance of the available electrocatalysts for hydrogen evolution reaction(HER)is far from satisfactory under large current density in alkaline *** we report a remarkably active and durable electrocatalyst,long and dense MoS2/Ni3S2 co-axial heterostructure nanowires on nickel foam(NF).Notably,it requires only 182 and 200 mV overpotential to achieve large current density of 500 and 1000 mA cm^-2,respectively,in alkaline solution,which are far superior to those of Pt/C-NF(281 and 444 mV)and the reported best non-noble metal catalysts(191 and 220 mV).The physical origin for this extraordinary HER performance is analyzed,which provides a useful guide for structure design of electrocatalysts to further improve their performance.
摘要:传统工业上,合成氨反应往往在高温高压下进行,造成了大量的能源消耗.因此,有必要发展绿色可持续的新方法,从而在温和条件下实现氨气的高效合成.从原子分子层面上理解合成氨的微观反应过程有利于高效高选择性催化剂的开发.本文系统探究了在金红石TiO_(2)(110)模型体系表面氨气生成的微观反应过程.利用程序升温脱附谱技术,发现了在金红石TiO_(2)(110)表面共吸附氮原子和水分子之后,在升温过程中,氨气可以生成并在400 K左右从五配位Ti^(4+)位(Ti_(5c))上脱附出去,这表明在金红石TiO_(2)(110)表面氨气的确可以在低温下生成.结果表明,桥氧列上的羟基和Ti_(5c)位上的水分子均可以提供氨气生成所需的氢原子.氢原子在金红石TiO_(2)(110)表面的迁移在氨气的生成过程中扮演了重要作用,通过改变水分子的覆盖度,氢原子的迁移方式会随着水分子覆盖度的改变而发生变化.当水分子的覆盖度较低时,氢键网络在金红石TiO_(2)(110)表面上尚未建立,氢原子主要以直接跃迁的方式迁移侄氮原子附近,其对应的扩散能垒约为1 eV:随着水分子覆盖度的逐渐增加,氢键网络在金红石TiO_(2)(110)表面逐步建立起来,此时氢原子更倾向于在氢键网络的辅助下迁移至氮原子附近,其对应的扩散能垒仅为0.2~0.3 eV.此外,吸附在氮原子附近的水分子也有可能直接与氮原子发生反应生成氨气.因此,在金红石TiO_(2)(110)表面,氮原子可能存在三种不同的加氢过程.实验结果不仅有助于深入理解合成氨反应中的加氢过程,同时也对催化剂的设计和优化提供了一种新思路.
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