Simultaneous determination of dissolved organic carbon and phosphorus in waters using flame ionization and photometric detectors

An apparatus with flame ionization and photometric detectors was assembled for the simultaneous determination of dissolved organic carbon (DOC) and phosphorus (DP) in waters. The optimum operating conditions were described. The long-term precision (relative standard deviation) is 5.8% for DOC and 5.2% for DP. The detection limits are 0.09 μg ml⁻¹ for DOC and 0.03 μg ml⁻¹ for DP. The responses for various DOC and DP compounds agreed almost with those obtained by combustion-infrared and persulfate digestion-colorimetric methods, respectively. DOC and DP in several water samples were determined by this method and other methods, and the results obtained by those methods were discussed.     

供热锅炉蒸汽湿度的实验研究

通过试验及分析，对供热锅炉蒸汽湿度的测定方法提出了建议，认为可采用开孔取样管装置取样测定饱和蒸汽湿度；当给水用钠离子交换处理时，采用碱度法或氯根法分析均可。所给出的简易测试法为准确测量锅炉热效率提供了方便。     

群决策在房屋结构可靠性评估中的应用

阐述了砌体结构房屋可靠性评估中，各影响因素权重的确定是重要而困难的问题。基于层次分析的群决策确定各因素权重分配时，可有效地减少人为因素的影响，从而使权重确定结果更加客观、科学、合理。     

基于子空间动态系数回归的系统谐波阻抗估计方法

系统谐波阻抗的准确估计是实现谐波责任定量划分的关键。新能源并网场景下用户侧谐波阻抗并非远大于系统侧谐波阻抗,现有估计方法精度降低甚至失效。文中提出一种基于子空间分解和动态系数回归的系统谐波阻抗估计方法。通过小波包分解将公共连接点(PCC)处谐波电压与电流的观测信号分解成多个子空间,并根据互信息值筛选出解释变量相关度最弱的子空间,以降低解释变量间相关性对回归分析的影响;考虑到网侧谐波波动会干扰PCC处谐波电压与电流间的相关性,将网侧谐波电压视作动态系数,并通过动态系数回归法求解系统谐波阻抗,以降低网侧谐波电压波动对估计结果的影响。仿真分析的结果表明,相比现有方法,所提方法拥有更好的估计精度与鲁棒性。     

固定舵二维修正弹外弹道仿真与动态模拟

为研究固定舵二维弹道修正弹的修正能力,采用流体力学分析软件Fluent与机械系统动力学自动分析软件Adams联合仿真方法建立了固定舵二维修正弹的动力学仿真模型。基于鸭舵修正原理提出了仿真环境下鸭舵减旋和测姿的模拟方法,在Adams软件环境下通过在舵片模型上建立Marker监测点实现了对鸭舵实时滚转角的直接监测;应用该仿真方法对横风作用力从1 N增大到10 N的情况进行仿真,相比于无风干扰,横偏增加了36.5%到298.0%;分别对10 N横风作用力、0.5°横向跳角和0.5°定起角干扰下的弹道修正进行了仿真。研究结果表明：相对于无修正情况下的横偏,在10 N横风作用力下的修正量能够达到90%,由跳角引起的横向、纵向落点偏差得到显著降低;通过与半实物仿真实验及实弹射击试验的对比,证明该仿真方法具有一定的合理性。     

粘性土填筑路堤的试验与施工措施

根据福州二环三期A7项目路基土工试验和施工现场压实试验结果,对粘性土路基施工产生裂缝的成因进行了综合分析,提出了施工中具体处理的技术措施,可供粘性土路基施工和监理人员参照应用     

静压平衡等速采样技术在转炉煤气测尘的应用

介绍了采用静压平衡等速取样技术测定煤气含尘量的原理、装置与方法。取样时通过控制采样流量，使样气流速模拟取样点管道中煤气流速达到等速取样的条件。该技术操作简单、取样时间短且准确度高，适用于周期性回收转炉煤气的测尘。     

等截面杆件固端弯矩的简化计算方法

本文介绍的固端弯矩的计算方法是指各种支座形式在集中荷载作用下 ,单跨等截面超静定梁固端弯矩归为统一的计算公式。对受均布荷载作用的情况 ,固端弯矩可以通过积分求出     

Structural classification of Quillaja saponins by electrospray ionization ion trap multiple-stage mass spectrometry in combination with multivariate analysis, proof of concept

MS² and MS³ spectra of thirteen previously identified saponin structures from Quillaja saponaria Molina were obtained by electrospray ionization ion trap multiple-stage mass spectrometry (ESI-ITMSⁿ) in positive ion mode. The spectra were analysed by partial least squares regression-discriminant analysis (PLS-DA) yielding a method that can classify the spectra according to saponin structure. For this method a referencing of the m/z axis was essential to obtain a correlation between peaks in the spectra and common structural elements. The MS² and MS³ spectra could be classified according to the structures of the oligosaccharides at C-3 and C-28 of the corresponding saponins. Terminal residues with the same mass, such as β-d-Apif and β-d-Xylp, could also be distinguished. The PLS-DA method was applied on Quillaja saponins separated from a commercial bark extract by reversed-phase chromatography.The method outlined here is applied on a specific group of Quillaja saponins, but can be used on other types of glycoconjugates. Combination of this technique with chromatography would give a very powerful tool for rapid identification of components in complex mixtures.     

Effects of Four Key Process Variables on Size Shrinkages of Low Temperature Co-Fired Ceramic Substrates

The effects of four key process variables on the size shrinkages of low temperature co-fired ceramic substrates were investigated using the methods of design of experiments (DOE), analysis of variance (ANOVA), and multivariable regression. The process variables investigated were raw tape thickness, laminating pressure, coining pressure, and coining time. The results revealed that coining pressure had the most significant effect on the size shrinkages of the low temperature co-fired ceramic samples under the process conditions set in this study. The average lateral size shrinkage and thickness shrinkage of the LTCC samples produced with a coining pressure of 320 MPa were significantly lower and higher than those produced with a coining pressure of 50 MPa with shrinkage differences of 3.6% and 6.2%, respectively. The effects of tape thickness, the interaction of tape thickness, laminating pressure, and coining pressure, the interaction of tape thickness and coining pressure, and the interaction of tape thickness and laminating pressure were also significant. Two regression equations were obtained and the shrinkage values could be estimated using them. The coefficients of determination R² were 99.9% and 98.9%, respectively, and the P values were smaller than 0.001 for the two regression equations. This can allow engineers to calculate the dimensions especially lateral dimensions and features such as pad pitches at the design stage and to set the process parameters at the manufacturing stage.