处理电镀废水中的微量铜(Ⅱ)的光度法测定

研究了Cu2+和5,8-二羟基-1,4-萘醌(Naph)的络合显色反应。试验结果表明,在pH为7的乙酸铵溶液中,OP乳化剂的存在下,有色溶液的最大吸收波长为350nm,摩尔吸光系数为1.83×104L/(mol·cm),方法检出限为3.5μg/L,Cu2+质量浓度在0～4.0mg/L范围内符合比耳定律,可用于测定处理电镀废水中的微量Cu。     

超细镍酸锂晶体对搪瓷密着强度影响的研究

将超细镍酸锂晶体磨加在搪瓷釉中,测试搪瓷的密着强度,通过电子显微镜观察搪瓷界面的显微形貌。实验结果表明,在搪瓷釉中磨加超细镍酸锂晶体能有效地提高搪瓷的密着强度。     

Microkinetic model for the pyrolysis of methyl esters: From model compound to industrial biodiesel

A tool for the generation of decomposition schemes of large molecules has been developed. These decomposition schemes contain radicals which can be eliminated from the model equations if both the μ‐hypothesis and the pseudosteady‐state approximation are valid. The reaction rate coefficients and thermodynamic parameters have been calculated by incorporating a comprehensive group additive framework. A microkinetic model for the pyrolysis of methyl esters with a carbon number of up to 19 has been generated using this tool. It is validated by comparing calculated and experimental yields of the pyrolysis of methyl decanoate and novel rapeseed methyl ester pyrolysis data in the temperature range from 800 to 1100 K and methyl ester partial pressure range from 1 × 10^?3 to 1 × 10^?2 MPa. This modeling frame work allows to not only assess the use of methyl ester mixtures as potential feedstock for olefin production but also their effect as blend‐in or trace impurity. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4309–4322, 2015     

Zero‐Modified Geometric INAR(1) Process for Modelling Count Time Series with Deflation or Inflation of Zeros

In this article, we propose a first‐order integer‐valued autoregressive [INAR(1)] process for dealing with count time series with deflation or inflation of zeros. The proposed process has zero‐modified geometric marginals and contains the geometric INAR(1) process as a particular case. The proposed model is also capable of capturing underdispersion and overdispersion, which sometimes are caused by deflation or inflation of zeros. We explore several statistical and mathematical properties of the process, discuss point estimation of the parameters and find the asymptotic distribution of the proposed estimators. We also propose a test based on our model for checking if the count time series considered is deflated or inflated of zeros. Two empirical illustrations are presented in order to show the potential for practice of our zero‐modified geometric INAR(1) process. This article contains a Supporting Information.     

8-羟基喹啉型吸附材料对重金属离子的吸附研究

以多孔型无机材料Si O2作载体,通过偶联剂γ-氨丙基三甲氧基硅烷的媒介作用,将5-氯甲基-8羟基喹啉(CHQ)分子接枝到硅胶表面,制备新型复合型螯合吸附材料CHQ-AMPS/Si O2。研究了接枝微粒CHQ-AMPS/Si O2对废水中重金属离子Pb2+和Ni2+的吸附行为,考察了接枝微粒CHQ-AMPS/Si O2对Pb2+和Ni2+的吸附动力学曲线和等温线,研究了温度和p H对接枝微粒CHQ-AMPS/Si O2吸附Pb2+和Ni2+的影响和其可再生性能。结果发现微粒CHQ-AMPS/Si O2对于Pb2+和Ni2+的吸附最适温度分别是35℃,25℃;最适p H分别是7和6。     

Oracle M‐Estimation for Time Series Models

We propose a thresholding M‐estimator for multivariate time series. Our proposed estimator has the oracle property that its large‐sample properties are the same as of the classical M‐estimator obtained under the a priori information that the zero parameters were known. We study the consistency of the standard block bootstrap, the centred block bootstrap and the empirical likelihood block bootstrap distributions of the proposed M‐estimator. We develop automatic selection procedures for the thresholding parameter and for the block length of the bootstrap methods. We present the results of a simulation study of the proposed methods for a sparse vector autoregressive VAR(2) time series model. The analysis of two real‐world data sets illustrate applications of the methods in practice.     

Testing Parameter Change in General Integer‐Valued Time Series

We consider the structural change in a class of discrete valued time series, which the conditional distribution belongs to the one‐parameter exponential family. We propose a change point test based on the maximum likelihood estimator of the model's parameter. Under the null hypothesis (of no change), the test statistic converges to a well‐known distribution, allowing the calculation of the critical value of the test. The test statistic diverges to infinity under the alternative, meaning that the test has asymptotic power one. Some simulation results and real data applications are reported to show the effectiveness of the proposed procedure.     

FABRICATION AND CRYSTALLINITY OF Bi2Sr2CaCu2O8+δ THIN FILMS BY MOLECULAR BEAM EPITAXY

在BiO--(Sr+Ca)O--CuO相图上的Bi₂Sr₂CaCu₂O_8+δ(Bi--2212) 相附近选择不同成分, 用分子束外延法制备成薄膜, 利用XRD, EDS,SEM和AFM研究了成分、衬底温度和臭氧分压对Bi--2212相薄膜成相的影响, 分析了生长速率和错配度对Bi--2212相薄膜质量的影响. 结果表明, Bi--2212相薄膜单相生成的成分范围 (原子分数) 分别为Bi 26.3%---32.4%, (Sr+Ca)37.4%---46.5%, Cu 24.8%---32.6%; 当衬底温度为720℃且臭氧分压为1.3×10^-3 Pa时, 在MgO(100) 衬底上生长出质量较高的c轴外延Bi--2212相薄膜; 通过调整生长速率、更换衬底和插入不同厚度的Bi₂Sr₂CuO_6+δ过渡层的方法, 可以改善Bi--2212相薄膜的结晶质量、表面形貌和导电特性.     

不同截面尺寸Cr8Mo2SiV和Cr12Mo1V1钢的组织与性能

对不同截面尺寸Cr8Mo2SiV和Cr12Mo1V1冷作模具钢的组织,共晶碳化物尺寸及不均匀度,冲击性能进行了研究。结果表明,Cr8Mo2SiV钢和Cr12Mo1V1钢退火组织均为球状珠光体上分布着碳化物;随热轧截面尺寸的增大,碳化物尺寸变大,分布均匀性变差。适当减小试验钢的截面尺寸,能够显著减小共晶碳化物的尺寸并改善其分布不均度,提高材料的冲击性能。     

MMS系列热力模拟实验机控制系统的优化

针对MMS系列热力模拟实验机的实验功能和性能要求,对其控制系统的结构、硬件配置、软件结构、应用程序进行了优化设计,将BP神经网络智能控制方法应用于主液压缸和液压马达的控制系统,提高了控制精度。