A normalized data-reusing least-mean-square algorithm of noise cancellation for magnetocardiography

An adaptive filter based on Data-Reusing Least-Mean-Square algorithm has been proposed and applied in magnetocardiography (MCG) to suppress ambient noise, Numerical simulation studies indicate that the adaptive filter is a powerful noise suppresser for correlated interferences, especially for those with amplitude changing and time delay.Also the filter has a wide frequency bandwidth. With this filter, the signal-to-noise ratio of an MCG is improved to the intrinsic noise level, The periodic average method for further improvement of the noise level in MCG is also discussed.     

基于AdaBoost-SVM算法的油井反向压驱效果预测方法

预测油井的反向压驱增油效果是反向压驱选井选层工作的重要环节.针对反向压驱历史数据规模有限的问题,提出一种基于AdaBoost-SVM的油井反向压驱增油效果预测方法.应用SMOTE算法对压驱历史数据进行过采样,并建立AdaBoost-SVM反向压驱增油效果预测模型,以对油井的压驱效果进行预测.在油井上的实际应用结果表明,该预测方法能够有效预测油井应用反向压驱工艺的增油效果,为进一步的选井选层工作提供参考.     

开放骨架磷酸铝合成中F~-对有机胺结构导向效应的影响

研究了在开放骨架磷酸铝合成中氟离子对乙二胺(en)和二乙烯三胺(deta)的结构导向效应的影响.在水热条件下,以乙二胺为结构导向剂,分别从摩尔组成为n(Al2O3)∶n(P2O5)∶n(en)∶n(H2O)=1.0∶1.5∶18.0∶147和n(Al2O3)∶n(P2O5)∶n(en)∶n(HF)∶n(H2O)=1.0∶1.5∶18.0∶3.0∶147的初始混合物中晶化出二维层状磷酸铝Al2P2O9·NH3(CH2)2NH3(Ui O-13)和Al F(HPO4)·NH2(CH2)2NH2(1);以二乙烯三胺为结构导向剂,分别从摩尔组成为n(Al2O3)∶n(P2O5)∶n(deta)∶n(H2O)=1.0∶4.0∶3.0∶153和n(Al2O3)∶n(P2O5)∶n(deta)∶n(HF)∶n(H2O)=1.0∶4.0∶3.0∶3.0∶153的初始混合物中晶化出了三维开放骨架磷酸铝Al4P5O20(H2O)2·C4N3H16(Al PO-CJ31)和一维链状磷酸铝Al2P4O10(OH)3F·C4N3H15(2),表明凝胶中的F-显著改变了乙二胺和二乙烯三胺的结构导向效应.详细对比分析了Ui O-13和化合物1以及AlPO-CJ31和化合物2的结构,探讨了F-对乙二胺和二乙烯三胺的结构导向效应的影响及F-与有机胺的协同结构导向效应.     

钾负载量对CuO/K_2CO_3/MgAl_2O_4催化剂高温NO_x储存还原性能的影响

制备了适用于高温氮氧化物储存还原(NSR)反应的Cu O/K_2CO_3/MgAl_2O_4非贵金属催化剂,考察了钾负载量对催化剂NSR性能的影响,发现钾主要以高分散K_2CO_3和体相K_2CO_3的形式存在.在稀燃条件下,NOx在体相K_2CO_3上形成了高温稳定的硝酸盐物种,而高分散K_2CO_3上形成的硝酸盐的高温稳定性则较差.当钾负载量较低时,催化剂的NOx储存能力有限,K_2CO_3主要以高分散形式存在,稀燃阶段形成的硝酸盐的热稳定性较低,高温NSR活性较低;而钾负载量过高时,K_2CO_3则会覆盖Cu O活性位,从而降低催化剂的NSR活性.在450℃的高温条件下,钾负载量为10%时,所制备催化剂的NOx储存还原能力最佳,NOx还原效率达到99.9%,是一种具有潜在应用前景的高温NSR催化剂.     

Cr3+ 掺杂近红外荧光材料的研究进展

近红外光谱检测技术具有非侵入性、便携性、响应速度快、效率高等特点,在食品分析、医学监测、虹膜识别和红外成像等领域具有广阔的应用前景。然而,近红外荧光材料面临发射谱带窄、热稳定性差的问题,极大制约了近红外器件的发展。为此,蓝光激发Cr3+掺杂的近红外发光材料在众多方案中优势显著。本综述总结了近年来Cr3+掺杂的宽带近红外荧光材料的最新研究成果,分析了Cr3+掺杂的近红外荧光材料量子效率、发射谱带、电声耦合效应和NIR pc-LED器件的封装,并阐述了Cr3+离子格位占据、敏化发光、发射谱带和热稳定性调控策略。最后,对高效宽光谱发射近红外发光材料的应用前景进行了展望。     

2-苯氧基乙酸苯胺超分子化合物的合成及其晶体结构

合成了2-苯氧基乙酸苯胺(1),其结构经X-射线单晶衍射表征.结果表明,1属于单斜晶系,P2(1)空间群,晶胞叁数为:a=13.422(3)A,b=6.740(17)A,c=15.645(4)A,α=90.000°,β=110.047(5)°,γ=90.000°,V=1 329.6(6)nm3Z=4,Dr=1.225 mg·cm-3,F(000)=520,μ=0.086 mm-1,R1=0.104 7,R2=0.059 1,ωR1=0.123 7,ωR2=0.107 9.1通过分子间氢键形成层状结构.     

AlAs/InSe范德华异质结构的光学和可调谐电子特性

由不同二维(2D)材料相互堆叠形成异质结构已成为目前的研究热点, 使用第一性原理的计算方法探究了AlAs/ InSe异质结构的几何结构、电子性能和光学性质. 结果表明, AlAs/InSe异质结构具有典型的Type-II型能带排列并且拥有着1.28 eV的间接带隙. 通过调节层间距或施加外部电场和应变, 可以有效地改变异质结构的带隙值. 有趣的是, 当应用5 V/nm的电场时, 异质结构实现了从Type-II向Type-I的转变. 此外, 与孤立单层相比, AlAs/InSe异质结构的吸光度明显提高, 特别是在紫外区域. 表明新型的二维AlAs/InSe异质结可以作为光电材料和紫外探测器件的有力候选者.     

细胞外囊泡的单颗粒分析技术

细胞外囊泡（Extracellular vesicles,EVs）是细胞分泌到细胞外基质中的纳米尺度的脂质小膜泡,携带着母细胞来源的各种生物活性分子,如蛋白质、核酸、脂质等,是细胞间沟通交流的信使。EVs参与免疫调控、血管新生、疾病发生、肿瘤转移等生理病理过程,广泛存在于各种体液中,在液体活检、疾病治疗中显示出巨大的应用前景,也因此成为生命科学领域炙手可热的前沿研究方向。然而EVs在粒径、生化组成等方面具有高度的个体差异性和多样性。因此,迫切需要发展EVs的单颗粒分析技术以精准表征EVs亚群的分子组成,深入了解其生物学功能,促进EVs临床诊断与治疗应用的发展。该文针对近年来发展的EVs的单颗粒分析技术进行综述,从检测原理、性能和应用范围等方面对这些技术进行讨论,并对单颗粒表征技术未来的发展趋势进行了展望。     

Spectroscopy and coherent manipulation of single and coupled flux qubits

Measurements of three-junction flux qubits, both single flux qubits and coupled flux qubits, using a coupled direct current superconducting quantum interference device （dc-SQUID） for readout are reported. The measurement procedure is described in detail. We performed spectroscopy measurements and coherent manipulations of the qubit states on a single flux qubit, demonstrating quantum energy levels and Rabi oscillations, with Rabi oscillation decay time TRabi =- 78 ns and energy relaxation time T~ = 315 ns. We found that the value of TRabi depends strongly on the mutual inductance between the qubit and the magnetic coil. We also performed spectroscopy measurements on inductively coupled flux qubits.     

Flux qubit with a large loop size and tunable Josephson junctions

We present the design of a superconducting flux qubit with a large loop inductance. The large loop inductance is desirable for coupling between qubits. The loop is configured into a gradiometer form that could reduce the interference from environmental magnetic noise. A combined Josephson junction, i.e., a DC-SQUID is used to replace the small Josephson junction in the usual 3-JJ (Josephaon junction) flux qubit, leading to a tunable energy gap by using an independent external flux line. We perform numerical calculations to investigate the dependence of the energy gap on qubit parameters such as junction capacitance, critical current, loop inductance, and the ratio of junction energy between small and large junctions in the flux qubit. We suggest a range of values for the parameters.