Small sample improvements in the threshold cointegration test using residual-based moving block bootstrap

A residual-based moving block bootstrap procedure for testing the null hypothesis of linear cointegration versus cointegration with threshold effects is proposed. When the regressors and errors of the models are serially and contemporaneously correlated, our test compares favourably with the Sup LM test proposed by Gonzalo and Pitarakis. Indeed, shortcomings of the former motivated the development of our test. The small sample performance of the bootstrap test is investigated by Monte Carlo simulations, and the results show that the test performs better than the Sup LM test.     

Spidermen Strategy for Stable 24% Efficiency Perovskite Solar Cells

The interface energetics-modification plays an important role in improving the power conversion efficiency (PCE) among the perovskite solar cells (PSCs). Considering the low carrier mobility caused by defects in PSCs, a double-layer modification engineering strategy is adopted to introduce the “spiderman” NOBF₄ (nitrosonium tetrafluoroborate) between tin dioxide (SnO₂ and perovskite layers. NO⁺, as the interfacial bonding layer, can passivate the oxygen vacancy in SnO₂, while BF₄⁻ can optimize the defects in the bulk of perovskite. This conclusion is confirmed by theoretical calculation and transmission electron microscopy (TEM). The synergistic effect of NO⁺ and BF₄⁻ distinctly heightens the carrier extraction efficiency, and the PCE of PSCs is 24.04% with a fill factor (FF) of 82.98% and long-term stability. This study underlines the effectiveness of multifunctional additives in improving interface contact and enhancing PCE of PSCs.     

偏最小二乘法同时测定食醋的有效成分和防腐剂的含量

偏最小二乘方法建立近红外光谱与组分浓度的多元校正模型,用于同时快速测定食醋的有效成分(总酸)和防腐剂(苯甲酸)含量。采用透射模式,样品不经任何处理测定近红外光谱。用17个食醋样品建立偏最小二乘法(PLS)模型,用3个样品作为预测样品以评估PLS模型。结果:食醋中的总酸和苯甲酸在2 125～2 325 nm区域之间,与光谱有良好的线性关系,总酸的PLS模型中,隐变量为3时,预测均方根误差0.038 7 g·L~(-1),总酸含量与光谱的线性相关系数达到0.999 7,相对预测误差5.89%;苯甲酸的PLS模型中,隐变量为6时,预测均方根误差降至0.013 8 g·L~(-1),苯甲酸含量与光谱的线性相关系数达到0.999 8,相对预测误差降至4.29%。     

不同因素对JS涂料性能测试结果的影响研究

GB/T23445-2009《聚合物水泥防水涂料》标准中对试样制备过程中的某些影响因素无明确规定,其中试样制备条件对测试结果影响较大,本文讨论了搅拌设备、搅拌速度、称料量、刮涂次数以及消泡方式5种因素对11个不同JS涂料样品拉伸强度和断裂伸长率的影响,并分析了影响机理.     

CFRC应力传感器中碳纤维均匀分散对导电性能的影响

讨论了碳纤维一水泥基复合材料（ＣＦＲＣ）应力传感器中碳纤维类型、长径比、均匀分散程度对导电性能的影响．     

Preparation and monovalent selective properties of multilayer polyelectrolyte modified cation‐exchange membranes

This study reports the modification of commercial cation‐exchange membrane by layer‐by‐layer adsorption of polyethyleneimine and poly(acrylic acid) (PAA) to endow them with monovalent ion selectivity. The chemical and morphological changes of the modified membrane surface were examined by ATR‐FTIR and SEM, respectively. The permselectivity for monovalent cations of the membranes was investigated by electrodialysis experiments. The effects of deposited bilayer number, the salt concentration, and pH of the dipping polyelectrolyte solutions on selectivity were investigated. Meanwhile, the resistance of membranes was measured taking energy consumption into consideration. The polyelectrolyte multilayer was crosslinked using epichlorohydrin to improve stability, and the durability of the composite membrane was studied. Separation mechanism of the composite membrane was also investigated. It is demonstrated that the bivalent cations are mainly rejected by electrostatic repulsion from the positive charge on the surface of the composite membranes. The sieving effect of the dense structure of skin layer becomes more pronounced with the number of deposited layers increased. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41488.     

铈对钢中氧化物,硫化物的影响及简要热力学分析

依据合金热力学原理，借助金相分析，电子探针分析，探讨了铈对高碳低合金风中的氧化物，硫化物的影响。结果表明，钢中添加铈，铈的氧化物，氧硫化物、硫化物将取代其他元素的氧化物，硫化物，且Ⅱ型硫化物消失，这一影响遵循热力学规律；铈还显著提高钢的洁净度。     

高频传输用FR—4环氧基玻璃布层压板的研究进展

系统地介绍了近年来改性ＦＲ－４层压板的研究进展,对通用ＦＲ－４与高性能ＦＲ－４层压板的频率特性,耐水性,耐热性,尺寸稳定性和钻孔性能之间的差别及其影响因素进行了分析和讨论,提出了采用氰酸酯树脂对环氧树脂进行改性,从而降低环氧树脂基体介电常数,介质损耗因素,为我国制造高频传输用高性能ＦＲ－４层压板提供了努力方向。     

预应力在2A12高强铝合金薄板焊接中的作用

目前理论与试验研究指出,焊接残余应力的水平与分布对铝合金薄板的尺寸稳定性影响很大。通过在两端引入平行于焊缝方向且低于材料屈服极限的预拉应力,借助X射线应力测试仪与三坐标测量机研究2A12高强铝合金薄板的焊后残余应力水平及分布与板的挠曲变形。结果表明,残余应力幅度可表征金属构件潜在尺寸变形能力,引入预应力可显著降低焊后残余应力水平,均化应力分布,并强化构件尺寸稳定性。     

High throughput mining and characterization of microsatellites from common carp genome

In order to supply sufficient microsatellite loci for high-density linkage mapping, whole genome shotgun (WGS) sequences of the common carp (Cyprinus carpio) were assembled and surveyed for microsatellite identification. A total of 79,014 microsatellites were collected which were harbored in 68,827 distinct contig sequences. These microsatellites were characterized in the common carp genome. Information of all microsatellites, including previously published BAC-based microsatellites, was then stored in a MySQL database, and a web-based database interface (http://genomics.cafs.ac.cn/ssrdb) was built for public access and download. A total of 3,110 microsatellites, including 1,845 from WGS and 1,265 from BAC end sequences (BES), were tested and genotyped on a mapping family with 192 individuals. A total of 963 microsatellites markers were validated with polymorphism in the mapping family. They will soon be used for high-density linkage mapping with a vast number of polymorphic SNP markers.