Box-Behnken Design响应面法优化银杏叶提取物醇提水沉工艺

目的优化银杏叶提取物的醇提水沉工艺。方法在单因素试验基础上,以总黄酮醇苷转移率、萜类内酯转移率及干物质得率为综合评价指标,通过Box-Behnken Design(BBD)响应面法对液料比、提取时间、提取次数、提取液浓缩倍数、加水倍数、冷沉时间进行考察。结果醇提水沉最佳工艺为液料比8∶1(V/m),提取时间1.0 h,提取次数3次,浓缩倍数3倍,加水倍数3倍,冷沉时间28.0 h。结论BBD响应面法优化得到的银杏叶提取物醇提水沉工艺科学、合理、稳定、可行。

The Adsorption of Pb(II)Using Silica Gel Synthesized from Chemical Bottle Waste:Optimization Using Box-Behnken Design

The adsorption of Pb(II)on silica gel synthesized from chemical glass bottle waste has been studied.The effect of independent variables(adsorbent dose,initial concentration of Pb(II),contact time,and pH)on the Pb(II)removal from water was evaluated and optimized using the Response Surface Methodology(RSM).Under optimized conditions(adsorbent dose:20 mg;contact time:30 min;initial Pb(II)concentration:120 mg.L^(−1);and pH:8),the removal of Pb(II)was 99.77%.The adsorption equilibrium data obtained from the batch experiment were investigated using different isotherm models.The Langmuir isotherm model fits the experimental data.This shows that the surface of the silica gel synthesized from chemical bottles waste was covered by a Pb(II)monolayer.XRF analysis showed that the synthesized silica gel had a SiO_(2) content of 75.63%.Amorphous silica was observed from XRD analysis.SEM-EDX characterization showed that Pb was adsorbed on the silica gel surface.SEM analysis showed that silica gel has irregular particles with a surface area of 297.08 m2.g^(−1) with a pore radius of 15.74 nm calculated from BET analysis.

Design and Characterization of an Aerosol Test Chamber for Emergency Response Patient Contamination Control Simulation and Research

Contaminated or infected patients present a risk of cross-contamination for emergency responders, attending medical personnel and medical facilities as they enter a treatment facility. The controlled conditions of an aerosol test chamber are required to examine factors of contamination, decontamination, and cross-contamination. This study presents the design, construction, and a method for characterizing an aerosol test chamber for a full-sized manikin on a standard North Atlantic Treaty Organization litter. The methodology combined air velocity measurements, aerosol particle counts and size distributions, and computational fluid dynamics modeling to describe the chamber’s performance in three dimensions. This detailed characterization facilitates future experimental design by predicting chamber performance for a variety of patient-focused research.

基于Design-Expert优化一款中药空气抑菌剂配方的研究

目的:以多种中药挥发油作为原料,开发一款高效广谱抑菌的空气抑菌剂。方法:选取丁香、艾叶、香茅3种挥发油,采用Design-Expert 12.0中自带的Optimal(custom)试验设计进行最优混料配方筛选试验。通过采样我校饭堂空间空气浮游菌,先按软件设计配方加样抑菌孵育并计数,再拟合出孵育菌落数与各挥发油配方比例的模型方程,最后计算出最佳抑菌效能配方比例,并采用实验室试验和现场试验验证优选配方。结果:利用286组抑菌孵育数据计算得出,孵育菌落数(Y)与各挥发油配方比例之间的拟合方程为Y=17.60A+53.01B+36.76C-106.11AB-84.87AC-63.93BC+782.79A^(2)BC-1178.89AB^(2)C+413.15ABC2。丁香与艾叶、香茅挥发油抑菌的交互作用对孵育菌落数量有显著影响(p<0.05)。最终选择的丁香、艾叶、香茅挥发油比例为45.2:41.6:13.2,该配方的实验室试验和现场试验验证了其抑菌效能良好。结论:中药抑菌挥发油复配后具有明显的增效作用。该配方的空气抑菌剂抑菌效果明显,气味芳香易于被人们接受,具有良好的市场前景和推广价值。

Box-Behnken Design效应面法在制剂处方优化中的应用

Box-Behnken Design(BBD)效应面法是一种实验条件寻优的方法 ,采用多元二次回归方程拟合各因素与响应值之间的函数关系,找出预测的响应最优值以及相应的实验条件,是种多因素非线性实验优化方法,可以评估因素的非线性影响,在处方优化中广泛使用。该设计方法试验次数少,应用方便,优选的条件预测性好。目前,微球、自乳化释药体系、脂质体等制剂的处方优化越来越多选择BBD的优化法。

Box-Behnken Design响应面法结合遗传算法和直接搜索算法优化丹栀逍遥散的提取工艺

目的:优化丹栀逍遥散的提取工艺。方法:采用加热回流提取法提取丹栀逍遥散组方药材样品粉末,以乙醇体积分数、提取时间和液料比(V/m)为考察因素,以栀子苷、芍药苷和丹皮酚3个指标成分的综合评分为评价指标,先采用Box-Behnken Design(BBD)响应面法进行试验设计,建立数学模型并获得目标函数后,结合遗传算法和直接搜索算法求解各因素的最优取值。结果:丹栀逍遥散中3个指标成分的最优提取工艺条件为60.8%乙醇提取3.1 h、液料比为15.72∶1(mL/g)。采用BBD响应面法或结合遗传算法和直接搜索算法所得的综合评分比较差异无统计学意义(P>0.05)。结论:经优化的工艺可用于丹栀逍遥散中3个指标成分的提取。BBD响应面法结合遗传算法和直接搜索算法在优化中药提取工艺方面具有一定优越性。

Box-Behnken Design-响应面法优化绿原酸转化为新绿原酸的工艺研究

利用Box-Behnken-响应面法优化绿原酸转化为新绿原酸的工艺条件。在单因素实验基础上,采用Box-Behnken Design实验设计,考察反应温度、反应时间及p H值对新绿原酸产率的影响,优化绿原酸转化为新绿原酸的工艺参数,得到模型预测公式。优化条件为:反应温度107℃,反应时间60 min,p H值为4.72时新绿原酸产率为64.20%,与模型预测值接近,方程拟合良好。采用优选工艺制备新绿原酸并精制纯化,分别运用HPLC、1H-NMR、13C-NMR、ESI-MS等方法对其进行含量测定和结构表征,结果表明纯化后纯度达98.78%,收率为87.37%。

Listening Test Design and Teaching

Listening importance attracts researchers' attention.Based on testing responses,typical listening items are introduced and suggestions are proposed to improve listing teaching.

基于Box-Behnken Design设计优化白藜芦醇纳米混悬剂的制备工艺

目的优化白藜芦醇纳米混悬剂的最佳制备工艺。方法采用反溶剂沉淀法制备白藜芦醇纳米混悬剂,以聚乙烯吡咯烷酮PVPK 17 PF为助悬剂,泊洛沙姆F188为表面活性剂,以粒径及多分散指数为响应值,应用Box-Behnken Design响应面实验设计优化白藜芦醇纳米混悬剂的最佳处方,并采用桨法进行体外释放实验评价其药物释放特征。结果优化后的纳米混悬剂处方为:白藜芦醇的质量浓度为29.2 mg/mL,助悬剂PVP K17PF的质量分数为0.38%,表面活性剂Poloxmer 188质量浓度为3.63 mg/mL。所制备纳米混悬剂的粒径大小为145 nm左右,在1 h的累积释放接近80%,释放机制为扩散作用为主。结论将白藜芦醇制备成纳米混悬剂可以提高白藜芦醇的溶出度,为难溶性药物白藜芦醇的进一步开发奠定了基础。

高硫煤矸石焙烧固硫的Box-Behnken响应面法优化研究

为实现高硫煤矸石焙烧过程中的高效固硫,采用工业废渣硼泥作为固硫剂,对煤矸石进行固硫试验.针对单因素试验的不足,采用Box-Behnken响应面法探索固硫剂用量、焙烧温度、焙烧保温时间等对煤矸石固硫率的影响,明确了各因素之间的交互作用.研究结果表明:在固硫剂中镁与煤矸石中硫的质量比(m_(Mg)/m_(S))为9,焙烧温度620℃、焙烧保温时间100 min时,煤矸石固硫率达到89.35%.对煤矸石固硫影响最大的因素为固硫剂用量,其次为焙烧温度,焙烧保温时间(2 h内)的影响较小.焙烧温度和固硫剂用量之间具有显著的交互作用.通过该方法优化的煤矸石固硫工艺可为高硫煤矸石的资源化利用提供一定技术支撑.

Design of Accelerated Life Test Plans——Overview and Prospect

Accelerated life test(ALT) is currently the main method of assessing product reliability rapidly, and the design of efficient test plans is a critical step to ensure that ALTs can assess the product reliability accurately, quickly, and economically. With the promotion of the national strategy of civil-military integration, ALT will be widely used in the research and development(R&D) of various types of products, and the ALT plan design theory will face further challenges. To aid engineers in selecting appropriate theories and to stimulate researchers to develop the theories required in engineering, with focus on the demands for theory research that arise from the implementation of ALT, this paper reviews and summarizes the development of ALT plan design theory. The development of the theory and method for planning optimal ALT for location-scale distribution, which is the most applied and mature theory of designing the optimal ALT plan, are described in detail. Taking this as the center of radiation, some problems that ALT now faces, such as the verification of the statistical model, limitation of sample size, solutions of resource limits, optimization of the test arrangement, and management of product complexity, are discussed, and the general ideas and methods of solving these problems are analyzed. Suggestions for selecting appropriate ALT plan design theories are proposed, and the urgent solved theory problems and opinions of their solutions are proposed. Based on the principle of convenience for engineers to select appropriate methods according to the problems found in practice, this paper reviews the development of optimal ALT plan design theory by taking the engineering problems arising from the ALT implementation as the main thread, provides guidelines on selecting appropriate theories for engineers, and proposes opinions about the urgent solved theory problems for researchers.

Development of a rapid test kit for SARS-CoV-2:an example of product design

We present an example of applying'need-driven'product design principle to the development of a rapid test kit to detect SARS-COV-2(COVID-19).The tests are intended for use in the field and,longer term,for home use.They detect whether a subject is currently infected with the virus and is infectious.The urgent need for large numbers of tests in field setting imposes constraints such as short test time and lack of access to specialist equipment,laboratories and skilled technicians to perform the test and interpret results.To meet these needs,an antigen test based on RT-LAMP with colorimetric readout was chosen.Direct use of swab sample with no RNA extraction was explored.After extensive experimental study(reported elsewhere),a rapid test kit has been fabricated to satisfy all design criteria.

Optimization of the Electrospinning Conditions by Box-Behnken Design to Prepare Poly(Vinyl Alcohol)/Chitosan Crosslinked Nanofibers

Electrospun poly(vinyl alcohol)/chitosan nanofibers had their solution and process parameters optimized using a Box-Behnken design and desirability function. Four factors (applied voltage, flow rate, distance tip-to-plate and amount of chitosan) were varied to produce electrospun mats with a low fiber diameter. An empirical model was developed for each response using response surface methodology (RSM), which revealed that flow rate had no significant influence on the assessed responses. With desirability function, the optimal conditions to produce the nanofibers were applied voltage of 13.1 kV, 30% chitosan concentration and distance tip-to-plate of 10 cm. The fiber diameter and standard deviation were 196.5 ± 28.3 nm, compared to the predicted values of 185.9 ± 26.8 nm. The desirability function allied with Box-Benhken design proved themselves important tools to predict process parameters for the development of nanofibers. The mats were crosslinked with glutaraldehyde for 24 h and 48 h and presented good water stability and enhanced mechanical properties.

Optimal Design of Multiple Stress Constant Accelerated Life Test Plan on Non-rectangle Test Region

For optimal design of constant stress accelerated life test(CSALT) with two-stress, if the stresses could not reach the highest levels simultaneously, the test region becomes non-rectangular. For optimal CSALT design on non-rectangle test region, the present method is only focused on non-rectangle test region with simple boundary, and the optimization algorithm is based on experience which can not ensure to obtain the optimal plan. In this paper, considering the linear-extreme value model and the optimization goal to minimize the variance of lifetime estimate under normal stress, the optimal design method of two-stress type-Ⅰ censored CSALT plan on general non-rectangular test region is proposed. First, two properties of optimal test plans are proved and the relationship of all the optimal test plans is determined analytically. Then, on the basis of the two properties, the optimal problem is simplified and the optimal design method of two-stress CSALT plan on general non-rectangular test region is proposed. Finally, a numerical example is used to illustrate the feasibility and effectiveness of the method. The result shows that the proposed method could obtain the optimal test plan on non-rectangular test regions with arbitrary boundaries. This research provides the theory and method for two-stress optimal CSALT planning on non-rectangular test regions.

Optimal Design of Multiple Stresses Accelerated Life Test Plan Based on Transforming the Multiple Stresses to Single Stress

For planning optimum multiple stresses accelerated life test plans, a commonly followed guiding principle is that all parameters of the life-stress relationship should be estimated, and the number of the stress level combinations must be no less than the number of parameters of the life-stress relationship. However, the general objective of an accelerated life test(ALT) is to assess the p-th quantile of the product life distribution under normal stress. For this objective, estimating all model parameters is not necessary, and this will increase the cost of test. Based on the theoretical conclusion that the stress level combinations of the optimum multiple stresses ALT plan locate on a straight line through the origin of coordinate, it is proposed that a design idea of planning the optimum multiple stresses ALT plan through transforming the problem of designing an optimum multiple stresses ALT plan to designing an optimum single stress ALT plan. Moreover, a method of planning the optimum multiple stresses ALT plan which can avoid estimating all model parameters is established. An example shows that, the proposed plan which only has two stress level combinations could achieve an accuracy no less than the traditional plan, and save the test time and cost on one stress level combination at least; when the actual product life is less than the design value, even the deviation of the model initial parameters value is up to 20%, the variance of the estimation of the p-th quantile of the proposed plan is still smaller than the traditional plans approximately 25%. A design method is provided for planning the optimum multiple stresses ALT which uses the statistical optimum degenerate test plan as the optimum multiple stresses accelerated life test plan.

Low overhead design-for-testability for scan-based delay fault testing

An efficient design-for-testability (DFT) technique is proposed to achieve low overhead for scan-based delay fault testing. Existing techniques for delay test such as skewed-load or broadside make the test generation process complex and produce lower coverage for scan-based designs as compared with non-scan designs, whereas techniques such as enhanced-scan test can make the test easy but need an extra holding latch to add substantial hardware overhead. A new tri-state holding logic is presented to replace the common holding latch in enhanced-scan test to get a substantial low hardware overhead. This scheme can achieve low delay overhead by avoiding the holding latch on the critical timing scan path. What’s more, this method can also keep the state and signal activity in the combinational circuit from the scan during data scan-in operation to reduce the power dissipation. Experiment results on a set of ISCAS89 benchmarks show the efficiency of the proposed scheme.

To What Extent does the Nature of the Language Skill being Taught Influence Test Design

There are many various kinds of English language tests in the world,ranging from IELTS(International English Lan⁃guage Testing System)to TOEFL(Test of English as a Foreign Language).All these tests are designed for different purposes relat⁃ing to various groups of testees.Usually the English language test covers the testing of the four language skills of reading,writing,listening and speaking.The essay will discuss the relationship between the nature of four skills and the test design respectively.

Modelling Design and Test of Steam Centrifugal Compressor

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Exponential System Reliability Test Design Based on Information Fusion

By analyzing the shortage of reliability test design and thinking over the producer's risk and consumer's risk, the information fusion technology is used to set up a reliability test design model( RTDM). By analyzing the demands and constraint conditions of the RTDM and with applications of Bayesian approach and Monte Carlo method( MCM),this paper puts forward the exponential distributed subsystems and the information fusion technology among them. According to the posteriori risk criteria,formulas of producer's risk and consumer's risk were also inferred,and with the help of Matlab software,selection of the optimum test plan was solved. Finally,validity of the model had been proved by a test of series parallel system.

Empirical Approach for Planning and Designing Constant Stress Accelerated Life Tests

Accelerated life testing(ALT)has been widely used to obtain information about the product's life characteristics at normal conditions in a relatively short period of time.Two key issues with ALT are test design and data analysis.The test design of constant stress ALT was studied in this paper.The test design usually combines engineering experiences with optimization models.Such approaches are hard to be implemented by practitioners.A"pure"empirical approach was presented to address this issue.With the proposed approach,some of the decision variables are determined based on the results from the literature,some of the other variables are determined based on engineering analysis and /or judgment,and the remaining variables are determined based on the empirical relations developed in this paper.A real-world example is included to illustrate the appropriateness of the proposed approach.