On fixed-accuracy and bounded accuracy confidence interval estimation problems in Fisher’s “Nile” example

Fisher’s “Nile” example is a classic that involves a bivariate random variable (X,Y) having a joint probability density function given by f(x,y;𝜃) = exp(?𝜃x?𝜃^?1y), 0<x,y<∞, where 𝜃>0 is a single unknown parameter. We develop (i) fixed-width and (ii) fixed-accuracy confidence intervals for 𝜃 with a preassigned confidence coe?cient. In problem (i), we develop a purely sequential estimation strategy along with its asymptotic properties. In problem (ii), we determine that a fixed-sample-size estimation strategy will su?ce and yet the requisite sample size would have to be found. We have done that both exactly as well as approximately and we report that for all practical purposes the approximations nearly provide the exact sample size whether it is small, moderate, or large. The last problem we address is bounded-accuracy fixed-sample-size estimation of P_𝜃{X>Y}. All theoretical properties are adequately validated by large-scale simulations.     

Open channel junction velocity prediction by using a hybrid self-neuron adjustable artificial neural network

Determining the appropriate hidden layers neuron number is one of the most important processes in modeling the Multi-Layer Perceptron Artificial Neural Network (MLP-ANN). Despite the significant effect of the MLP-ANN neurons number on predicting accuracy, there is no definite rule for its determination. In this study, a new self-neuron number adjustable, hybrid Genetic Algorithm-Artificial Neural Network (GA-ANN), is introduced and its application examined on the complex velocity field prediction of an open channel junction. The results of GA-ANN were compared with those got by the Genetic Programming (GP) method as two applications of the Genetic Algorithm (GA). The comparisons showed that the GA-ANN model can predict the open channel junction velocity with higher accuracy than the GP model, with Root Mean Squared Error (RMSE) of 0.086 and 0.156, respectively. Finally the equation, obtained by applying the GA-ANN model, predicting the velocity at the open channel junction is presented.     

Three-point-support method based on position determination of supports and wafers to eliminate gravity-induced deflection of wafers

The flatness measurement of large and thin wafers is affected greatly by gravity. Inverting method is often used to cancel the effect. However, it is required that the positions of the supports and wafers are perfectly symmetric about the inversion axis. In this study a three-point-support method based on position determination of supports and wafers was proposed. The supporting balls and the wafer were placed in arbitrary positions and their positions were obtained by measurement and fed into the FEM model which was developed to calculate the gravity-induced deflection (GID). The methods to acquire the positions of the supports and the wafer were proposed. The position measurement accuracy of the supports was improved greatly by circle fitting to the profile of the supporting ball. Wafer edge point was obtained accurately as the intersection point between the wafer surface line and the edge profile. The method to measure the wafer thickness using only one displacement sensor on the same equipment was presented. The simulation results were verified by experimental results. The centering device for the wafer and the positioning accuracy requirements of the supports are not needed any more. The effect of the positions of the supports and the wafer was reduced to be less than 1 μm for a 300 mm diameter and 397 μm thickness wafer with GID over 140 μm. This method could also be used for accurate flatness measurement of other large and thin panels.     

涂料中溶剂定性定量测定方法的探讨

以实际经验为基础并结合具体实例,探讨了涂料中溶剂定性定量的测定方法,包括内标物、稀释剂的选择以及其中可能发生的问题,并提出建立相应的记录方法。     

在用工业管道风险研判方法

借鉴国际管道技术委员会对输气管道提出的失效原因以及RBI思路，利用“专家打分法”对管道安装、维护、保养、检验等各个环节，量化发生事故的可能性和后果的严重程度，从而以半定量法确定在用工业管道风险值，进而进行风险预警，为压力管道使用单位、河北省质监局安全监察工作提出合理化建议。     

代森锌检测方法综述

介绍了代森锌的结构、理化性质及危害,总结了分光光度法、顶空气相色谱法、高效液相色谱、液相色谱串联质谱法等对代森锌定性定量分析方法,提出各检测方法的优缺点,并对防污涂料中代森锌的检测进行了先期研究。     

Comparison of steam-alkali-chemical and microwave-alkali pretreatment for enhancing the enzymatic saccharification of oil palm trunk

This paper demonstrates two different pretreatment protocols for oil palm trunks (OPT); steam-alkali-chemical (SAC) and microwave-alkali (Mw-A) method. The composition, morphology, structure and crystallinity of OPT before and after pretreatment were analyzed. The effectiveness of the pretreated methods was investigated by performing enzymatic saccharification on the OPT. The physiochemical factors namely: enzyme ratio (cellulase to β-glucosidase), pH, temperature and substrate loading (w/v) on enzymatic saccharification were also investigated. The pre-determined optimal conditions were then used for further enzymatic hydrolysis of raw and pretreated OPT substrates. The results revealed a huge degree of reduction in lignin, up to 89% for SAC treated OPT and at least 15% for Mw-A treated OPT sample as compared to untreated ones. High glucose accumulation (79.4%) was obtained after 72 h saccharification for both pretreated OPT samples.     

矿石中氧化铝的多种分析测试方法比对

通常情况下,矿石中氧化铝的前处理一般依据GB/T14565-93及DZG93-05分别采用Na2CO3及Na OH碱熔前处理溶矿,EDTA络合返滴定容量法测定矿石中氧化铝的含量,结果准确,重现性好,却费时相对较长。本文主要提出了采用盐酸、硝酸、硫酸、高氯酸、氢氟酸,加热溶解,盐酸、硝酸、王水浸提等多种矿石中三氧化二铝的熔(溶)矿及分析测试方法,引入的氢氟酸有效打开矿物中的硅酸盐,使溶样更加完全,测试体系更纯净,操作简便。试验结果表明,酸溶溶矿样品更适于采用DZG93-05EDTA络合醋酸锌容量法(p H~5.9)及ICP-OES法进行测定,对于氧化铝含量低于20%的矿石样品,并不含有一水硬铝石的矿物,酸溶溶矿法测定矿石中氧化铝的含量结果可靠,有较强的普遍性和适用性。     

An analytical-numerical approach for parameter determination of a five-parameter single-diode model of photovoltaic cells and modules

Parameter extraction of the five-parameter single-diode model of solar cells and modules from experimental data is a challenging problem. These parameters are evaluated from a set of nonlinear equations that cannot be solved analytically. On the other hand, a numerical solution of such equations needs a suitable initial guess to converge to a solution. This paper presents a new set of approximate analytical solutions for the parameters of a five-parameter single-diode model of photovoltaic (PV) cells and modules. The proposed solutions provide a good initial point which guarantees numerical analysis convergence. The proposed technique needs only a few data from the PV current-voltage characteristics, i.e. open circuit voltage V_oc, short circuit current I_sc and maximum power point current and voltage I_m; V_m making it a fast and low cost parameter determination technique. The accuracy of the presented theoretical I–V curves is verified by experimental data.     

钢铁中磷含量测定方法的研究

介绍了几种钢铁中磷含量的测定方法,着重对铋磷钼蓝分光光度法进行了研究,阐述了实验所需仪器、试剂以及实验试剂制备流程,通过探讨实验的准确度与精密度,得出了一些有意义的结论。