以加权单纯形法研究光度分析的最优化设计

分析化学中最优的实验设计方案近年已取得很大的突破,特别是在单纯形领域,优秀的论文不断出现,国内已有这方面的综述及报导。自一九六二年提出基本的单纯形法,至今已有改进的单纯形法,加权形心单纯形法等相继出现。本文在加权单纯形法的基础上提出比较完整的实验方案。以该法验证了一个数学模型及两个多元络合物体系,说明     

单纯形最优化法在氢化物原子吸收分析中的应用

单纯形法^[1-7]是一种动态寻优方法。它能在交互作用复杂，因素较多的场合使用，对实验有全面优化的效果，克服了单因素优选法无法考虑各因素间的交互影响、 准确性低、工作量大的缺点。它能在实验次数较少的情况下，快速的找出接近最佳分析条件组合，综合优化性能指标较小。     

用改进单纯形优化法对火焰AAS测定铜最佳条件的研究

用改进单纯形法对火焰ＡＡＳ测定铜的条件进行优化，并与传统方法进行了比较。结果表明，改进单纯形优化法实验次数少，灵敏度提高，线性关系好。     

六、最优化技术在分析测试中的应用

本文介绍了一些在分析测试中常用的优化方法。单因素问题可采用消去法进行优化,多因素问题常用轮换法、逐步登高法及单纯形法进行优化。     

多目标单纯形法研究催化动力学分析法的最优化设计

催化动力学分析法灵敏度高、设备简单,近年来发展很快,本文提出了多目标单纯形方法,利用罚函数处理约束问题,通过对汞、银催化亚铁氰化钾和硫脲的反应测定汞、银。实验验证,多目标单纯形调优比单因素调优法速度快,表观摩尔吸光系数明显提高。 1 数学原理 在实验设计的最优化方法中,单纯形法是一个十分有效的直接调优方法,本文讨论     

改进加权单纯形方法在反相高效液相色谱操作条件最佳化中的应用

本文介绍了改进加权单纯形方法(MWCM)的寻优规则,较系统地考察了MWCM方法在反相HPLC操作条件最佳化中的应用。通过对反相色谱二元和三元体系操作参数的优化选择,确证了方法的可靠性。与等度单纯形法及改进单纯形法相比,MWCM方法具有更高的寻优效率和寻优精度。此外,还对初始单纯形的选择方法进行了讨论。     

基于问题导向学习法的分析化学实验与理论知识融合的教学改革——以“水硬度的测定”为例

分析化学实验是一门兼具理论性、实践性和应用性的课程,主要训练学生规范操作并培养学生运用分析化学理论知识解决实际问题的能力。目前普遍存在着分析化学实验课程教学与理论教学严重脱节的问题,学生习惯“照方抓药”。本文将问题导向学习法应用于分析化学实验教学,通过改进教学模式、完善课程内容和优化考核方式开展教学改革,促进实验与理论教学的有效融合,充分调动学生的学习自主性,培养学生观察、思考、分析和解决问题的能力,有效提高实验课的教学效果。     

改进加权单纯形方法在反相高效液相色谱操作条件最佳化中的应用

 ]本文介绍了改进加权单纯形方法（MWCM）的寻优规则，较系统地考察了MWCM方法在反相HPLC操作条件最佳化中的应用。通过对反相色谱二元和三元体系操作参数的优化选择，确证了方法的可靠性。与等度单纯形法及改进单纯形法相比，MWCM方法具有更高的寻优效率和寻优精度。此外，还对初始单纯形的选择方法进行了讨论。     

计算机在测试数据统计处理中的应用：Ⅶ.单纯形优化法及其计算机程序

本文就单纯形优化法中的两种主要方法,基本单纯形法和改进单纯形法作了简要介绍,提出了适用于上述两种单纯形的计算机程序,最后均用实例作了说明。     

基于ZIF-8/WCNT电化学传感器检测呋喃西林在实验教学中的设计与探索

介绍一个新创综合实验，基于Zn-甲基咪唑金属有机框架材料(ZIF-8)和碳纳米管(WCNT)电化学传感器检测呋喃西林，包括金属框架材料的合成、传感器制备、测定条件优化、分析方法建立等多个模块。本实验切合本科实验教学需求，涉及分析化学和材料化学等二级学科，具有较强的交叉性和可拓展性，适合于分析化学实验教学。     

Effects of Electronic Correlations for Adiabatic Electrochemical Reactions of Electron Transfer in Electrode Models with Nearly Empty and Nearly Filled Conduction Bands: Adiabatic Free Energy Surfaces

Adiabatic free energy surfaces (AFES) for adiabatic electrochemical reactions of electron transfer (ARET) are computed with exact allowance for electron–electron correlation effects (EECE) in models of electrode with nearly empty and almost filled conduction bands and analyzed on the basis of a diagram of kinetic modes obtained earlier. The EECE role in ARET for an electrode with an arbitrary Fermi level in a conduction band of an arbitrary width is discussed. In the general case, allowing for EECE gives at some model parameters results other than for the Fermi level coinciding with the conduction band center (model of a surface molecule, MSM). As in the case of MSM considered previously, EECE considerably reduce activation free energies and at some model parameters give qualitatively different AFES.     

Uniform-sized molecularly imprinted polymer for metsulfuron-methyl by one-step swelling and polymerization method

Uniform-sized molecularly imprinted polymer (MIP) beads for metsulfuron-methyl (MSM) were firstly prepared by one-step swelling and polymerization method using 4-vinylpyridine (4-VPY) and ethylene glycol dimethacrylate (EDMA) as functional monomer and cross-linker, respectively. The preparation was optimized by varying the ratio of MSM to 4-VPY. The chromatographic behaviors of MSM and other structurally related sulfonylureas (SUs) on the resultant MIP column were evaluated. The imprinted polymer revealed specific affinity to the template and the fair resolution of SUs was also obtained. Furthermore, the uniform-sized MSM-MIP was used as the solid phase extraction (SPE) material to enrich MSM in real water samples before reversed-phase HPLC (RP-HPLC) analysis. The recovery of MSM from 100 mL of drinking water at a 50 ng/L spike level was 99.59% with R.S.D. of 1.13%. The detection limit was about 6.0 ng/L of MSM when enriching a 100 mL water sample.     

PLA/MSM缓释微球的制备及生物活性

采用膜乳化-液中干燥法制备出担载二甲基砜(MSM)的聚乳酸(PLA)微球(PLA/MSM), 并研究了膜孔径、 搅拌转速和MSM浓度对载药微球形貌、 尺寸、 载药量、 体外释放及细胞活性的影响; 采用场发射环境扫描电子显微镜(ESEM)观察微球形貌、 尺寸及分布, 用等离子体发射光谱(ICP-AES)法检测PLA/MSM微球载药量、 包封率及体外释放, 采用ESEM观察微球内部结构, 并通过体外细胞培养和噻唑蓝(MTT)法检测MC-3T3-E1细胞的增殖能力. 研究结果表明, 膜乳化法制备的载药微球规整, 呈典型的圆球状, 表面光滑, 内部有多孔结构. 当膜孔径为5.1 μm且搅拌转速为500 r/min时, PLA/MSM微球大小更为均一; 当体系中MSM质量分数为8.6%时, 载药量可达到77.43%. 随着膜孔径减小及药物浓度的增加, 体外释放速率加快, 但初期均无明显的突释现象, 约10 d后累积释放量达到89.2%. 细胞实验结果显示, 在膜孔径为5.1 μm且MSM质量分数为8.6%的条件下, 制备的载药微球在细胞培养7 d时表现出明显的促增殖作用.     

Molecularly imprinted polymer for metsulfuron-methyl and its binding characteristics for sulfonylurea herbicides

A molecularly imprinted polymer (MIP) was prepared using metsulfuron-methyl (MSM) as the template molecule. A combinatorial protocol has been employed to optimize the polymer in terms of the kind and relative amounts of functional and cross-linking monomers. A copolymer of 2-(trifluoromethyl)acrylic acid (TFMAA) and divinylbenzene (DVB) showed the highest binding capacity for MSM. The binding characteristics of the imprinted polymers and MSM were evaluated in various solvents using equilibrium binding experiments. The results showed that the MIP binds MSM only in dichloromethane, which was used as the porogen during polymerization. Scatchard plot analysis revealed that two classes of binding sites were formed in the imprinted polymer with dissociation constants of 32.3 μmol l⁻¹ and 1.7 mmol l⁻¹, respectively. The specificity of the imprinted polymer was investigated by binding assays using MSM and other structurally related sulfonylurea herbicides. The results indicated that the imprinted polymer showed a marked selectivity for MSM.     

Zn(Ⅱ)-EDTA和Cd(Ⅱ)-EDTA在草酸根掺杂溴化银颗粒乳剂中的增感效应

使用反馈式微机控制双注乳化仪,在晶体生长过程特定时间内,加入一定量的草酸盐,制得了草酸根离子处于晶体次表面的立方体溴化银微晶乳剂,并对其进行传统的硫加金化学增感、Zn(Ⅱ)-EDTA或Cd(Ⅱ)-EDTA增感以及光谱增感.对实验过程的考察和感光性能的测试结果表明,Zn(Ⅱ)-EDTA或Cd(Ⅱ)-EDTA对细微粒溴化银颗粒乳剂均有显著的增感效应;Zn(Ⅱ)-EDTA或Cd(Ⅱ)-EDTA增感可在传统硫加金增感基础上与光谱增感协同作用,三者具有兼容和可加和性;Zn(Ⅱ)-EDTA或Cd(Ⅱ)-EDTA增感可在传统硫加金增感与光谱增感协同作用的基础上,与草酸根内部掺杂增感兼容,实现四者的协同作用,而不引起乳剂灰雾增加.     

痕量铜在8-羟基喹啉碳糊化学修饰电极上催化溶出伏安法的研究

我们研究铜在8-羟基喹啉(HOX)碳糊化学修饰电极上的阴极溶出伏安特性时,发现铜与HOX生成的配合物在电极上可还原为低价铜的HOX配合物,后者可催化氢在该电极上的放电,产生一灵敏的催化氢波,由于该波是在化学修饰电极基础上得到的,因而具有良好的选择性与灵敏度,用于人发及血中铜的测定,效果较好,初步探讨了催化氢波的反应机理。     

螯合剂与牛血清白蛋白竞争镍作用的研究

用凝胶色谱法研究了13种螯合剂使牛血清白蛋白镍配合物BSANi(Ⅱ)中的镍活动化的能力,发现DTPA、NTA等氨羧类螯合剂有较好的竞争能力,而巯基类较差。用透析法研究了螯合剂与BSANi(Ⅱ)反应动力学机理,结果表明,在pH7.4和4℃时,L-组氨酸、EDTA为解离机理,而亚氨二乙酸,二乙三氨五乙酸为加合机理。测定了有关的动力学参数,依据竞争能力参数F讨论了可能作为治疗镍中毒的促排螯合剂。     

铜(Ⅰ，Ⅱ)配合物的合成、结构与性质

在室温、有关配体存在下,利用金属铜粉和过氧化苯甲酰的氧化加成配位反应合成了四种铜(Ⅱ)配合物(配体分别为联吡啶、双二苯基膦乙烷、2-氨基吡啶、苯并咪唑)。同时又利用双齿有机膦配体(dppm=双二苯基膦甲烷,dppe=双二苯基膦乙烷,dppp=双二苯基膦丙烷,dppb=双二苯基膦丁烷)和金属铜盐的还原取代反应合成了四种一价铜(Ⅱ)配合物。通过元素分析确定了配合物的组成,经X射线四圆单晶衍射确定了配合物的分子结构,配合物的晶体结构由直接法和Fourier合成方法解出。利用电子光谱等手段研究了氧化加成配位和还原取代配位反应的机理。初步建立了一套简单有效的合成铜(Ⅰ,Ⅱ)配合物的新方法。     

Fiber optic multi-channel protein detector for use in preparative continuous annular chromatography

On-line coupling continuous-flow liquid membrane extraction (CFLME) with HPLC, a novel automatic system was developed for the determination of sulfonylurea herbicides in water. After an automatic trace-enrichment process by CFLME, which is the combination of continuous flow liquid-liquid extraction and support liquid membrane (SLM) extraction, the target analytes were concentrated in 50 microl of 0.2 M Na2CO3-NaHCO3 (pH 10.0) buffer. The concentrated sample solutions were injected directly onto a C18 analytical column with a valve, and detected at 240 nm with a diode array detector. Metsulfuron methyl (MSM), and DPX-A 7881 were baseline separated with a mobile phase consisting of methanol and 67 mM KH2PO4-Na2HPO4 (pH 5.91) buffer (45+55, v+v) at a flow-rate of 1.0 ml min(-1). With an enrichment time of 10 min and enrichment sample volume of 20 ml, the enrichment factors and detection limits are 100 and 0.05 microg l(-1) for MSM, and 96 and 0.1 microg l(-1) for DPX-A 7881, respectively. The linear range and precision (RSD) are 0.1-50 microg l(-1) and 7.0% for MSM, and 0.2-50 microg l(-1) and 9.2% for DPX-A 7881, respectively. This proposed method was applied to determine MSM and DPX-A 7881 in seawater, tap water, and bottled mineral water with spiked recoveries in the range of 83-95% for MSM and 88-100% for DPX-A 7881, respectively.     

Optimization of Surfactin Production by <Emphasis Type="Italic">Bacillus subtilis</Emphasis> Isolate BS5

Bacillus subtilis BS5 is a soil isolate that produces promising yield of surfactin biosurfactant in mineral salts medium (MSM). It was found that cellular growth and surfactin production in MSM were greatly affected by the environmental fermentation conditions and the medium components (carbon and nitrogen sources and minerals). Optimum environmental conditions for high surfactin production on the shake flask level were found to be a slightly acidic initial pH (6.5-6.8), an incubation temperature of 30 degrees C, a 90% volumetric aeration percentage, and an inoculum size of 2% v/v. For media components, it was found that the optimum carbon source was molasses (160 ml/l), whereas the optimum nitrogen source was NaNO(3) (5 g/l) and the optimum trace elements were ZnSO(4).7H(2)O (0.16 g/l), FeCl(3).6H(2)O (0.27 g/l), and MnSO(4).H(2)O (0.017 g/l). A modified MSM (molasses MSM), combining the optimum medium components, was formulated and resulted in threefold increase in surfactin productivity that reached 1.12 g/l. No plasmid could be detected in the tested isolate, revealing that biosurfactant production by B. subtilis isolate BS5 is chromosomally mediated but not plasmid-mediated.