Comparison of analytical methods for the quality control of a new formulation containing soy extract and melatonin

Three analytical methods have been developed and compared for the quality control of a new formulation (Soymen GN(R) capsules) containing soy extract and melatonin for the treatment of menopausal symptoms. The first method is based on MEKC with diode-array detection, using a mixture of basic carbonate buffer (95%) and methanol (5%), containing 55 mM SDS, as the BGE. The second method is an HPLC method with UV detection at 260 nm. The third method is an HPLC method coupled to amperometric detection which is carried out at an oxidation potential of +0.8 V. In both HPLC systems, the chromatographic separation is obtained on an RP C18 column using a mixture of ACN and an acidic phosphate buffer (25:75 v/v) as the mobile phase. A feasible pretreatment procedure with a methanol/water mixture has been implemented to achieve the quantitative extraction of the main soy isoflavones and of melatonin from the capsules. The results obtained with the three methods are in good agreement with each other and satisfactory in terms of linearity (r(2) >0.9996), precision (RSD <5.4%) and accuracy (recovery >97%). Thus, each of the three analytical methods seems to be suitable for the simultaneous analysis of the main soy isoflavones and melatonin in the new commercial formulation.     

中性线修正型变截面梁类构件压电控制

传统绝对节点坐标法(absolute nodal coordinate formulation,ANCF)在变截面梁类构件建模过程中常以几何中位线等效构造单元中性线,难以对变截面单元位移场状态进行精确描述.为解决此类问题,本文以中细型变截面梁类构件为研究对象,深入考虑变截面结构几何因素及复合材料属性对变截面梁类构件中性...     

基于贝叶斯参数优化的无模型自适应硅单晶直径控制

直拉硅单晶的生长过程涉及多场多相耦合与复杂的物理化学变化,其中工艺参数的波动是导致晶体直径不均匀的重要原因,如何实现工艺参数的控制以获得理想的、均匀的晶体直径具有重要的研究意义。本文分析现有控制方法存在不稳定以及控制效果不佳的问题后,提出基于贝叶斯参数优化的无模型自适应控制模型来控制硅单晶生长过程中的晶体直径。首先以坩埚上升速度与加热器的功率作为控制输入参数,晶体直径作为输出,搭建无模型自适应控制模型,并分析算法的稳定性。其次将控制模型进行仿真实验,发现硅单晶直径控制模型中不同的超参数设定会影响控制过程的迭代次数以及控制效果。最后,利用贝叶斯优化超参数的取值范围,并进行最终的仿真实验,结果表明,经贝叶斯参数优化后的控制模型计算快、迭代次数少,输出的晶体直径稳定,同时将生长工艺参数控制在实际生产要求范围内。因此,基于贝叶斯参数优化的无模型自适应控制实现了硅单晶直径均匀稳定的有效控制,具有结合工程背景的实际应用前景。     

电控摩擦离合器的初步实验研究

以十二烷基磺酸钠水溶液作为润滑液,以石墨作为辅助电极,以氮化硅／黄铜摩擦片组成摩擦副,考察了自行研制的电控摩擦离合器试验台的工作特性及摩擦力矩对外加电场响应特性。结果表明,当外加电压从OV增加到20V时,电控摩擦离合器的摩擦力矩增大约2倍,摩擦力矩随外电压变化的响应时间约为3s。据此可以认为,电控摩擦技术可望应用于摩擦传动装置。     

Time behavior of stressed nonhierarchical networks

In this paper it is shown, by means of simulation, that interesting time behavior is observed for damaged and overloaded networks, and that adaptive, decentralized intelligence can have a dramatic influence on the overall network performance. The time behavior of nonhierarchical networks is modeled by a system of nonlinear difference equations among global variables, and bistability is shown to exist. Using a simple adaptive control mechanism, it is shown that, depending upon the value of a certain network variable, either limit cycle or steady state behavior results. A few ideas are discussed for applications of nonhierarchical communications to cellular automata and to decision-making systems.     

Development of Improved High-Performance Liquid Chromatography Method for the Determination of Residual Caprylic Acid in Formulations of Human Immunoglobulins

Quality control of human immunoglobulin formulations produced by caprylic acid precipitation necessitates a simple, rapid, and accurate method for determination of residual caprylic acid. A high-performance liquid chromatography method for that purpose was developed and validated. The method involves depletion of immunoglobulins, the major interfering components that produce high background noise, by precipitation with acetonitrile (1:1, v/v). Chromatographic analysis of caprylic acid, preserved in supernatant with no loss, was performed using a reverse-phase C18 column (2.1 × 150 mm, 3 μm) as a stationary phase and water with 0.05% TFA–acetonitrile (50:50, v/v) as a mobile phase at a flow rate of 0.2 mL/min and run time of 10 min. The developed method was successfully validated according to the ICH guidelines. The validation parameters confirmed that method was linear, accurate, precise, specific, and able to provide excellent separation of peaks corresponding to caprylic acid and the fraction of remaining immunoglobulins. Furthermore, a 2⁴⁻¹ fractional factorial design was applied in order to test the robustness of developed method. As such, the method is highly suitable for the quantification of residual caprylic acid in formulations of human immunoglobulins for therapeutic use, as demonstrated on samples produced by fractionation of convalescent anti-SARS-CoV-2 human plasma at a laboratory scale. The obtained results confirmed that the method is convenient for routine quality control.     

透平叶栅三维粘性气动反问题的控制理论方法

将基于控制理论的形状优化设计方法应用于粘性可压流动条件下的透平叶栅三维气动反设计,详细推导了三维N-S方程伴随系统的偏微分方程组及其各类边界条件.讨论了伴随系统的解的适定性条件,并由此给出应用N-S方程进行气动优化的目标函数的选取限制.研究了伴随方程的数值求解技术,给出敏感性导数的最终计算式,结合拟牛顿算法发展了三维透平叶栅粘性反问题的气动设计方法.     

反射式红外传感器在智能型节水系统中的应用

利用反射式红外传感器和少量的电子器件(单稳态触发器),研制了智能型节水控制系统。该系统能够识别是否有人入厕,酌情产生冲洗信号, 躯动进水电磁阀开启,向浮球式水箱内注水,待注满足以冲刷干净所需的两水箱水后,便自动地切断电磁阀中电源,达到了既卫生又节约的目的。在某一教学楼应用该系统一年多来,与无使用此系统的同规模另一教学楼相比,节水约70％。该系统元件少、成本低、结构合理、工作可靠、安装容易、维修方便,有广阔的应用前景。     

重频XeF(C-A)蓝绿激光器中XeF2浓度的监测与控制

介绍了采用光谱吸收法实时监测重复频率XeF(C-A)蓝绿激光器中XeF2气体浓度的原理和控制XeF2气体浓度的方法;给出了监测窗中XeF2气体浓度与激光器气室中的XeF2气体浓度之间的关系,获得了在不同主/载气路气流量条件下激光器气室中XeF2气体浓度值,通过调节主/载气路的气流量实现了对激光器腔室内XeF2气体浓度的控制,保证了XeF(C-A)蓝绿激光器1 Hz重频运行。     

多量子比特核磁共振体系的实验操控技术

随着量子信息与量子计算科学的发展,量子信息处理器被广泛地用于量子计算、量子模拟、量子度量等方面的研究.为了能在实验上实现这些日益复杂的方案,将量子计算机的潜能转化成现实,需要不断提高可操控的量子体系比特位数,实现更复杂的量子操控.核磁共振自旋体系作为一个优秀的量子实验测试平台,提供了丰富而又精密的量子操控手段.近几年来在此平台上进行了不少的多量子比特实验,发展并积累了一系列的多量子比特实验技术.本文首先阐述了核磁共振体系多量子比特实验中的实验困难,然后结合7量子比特标记赝纯态制备以及其他有关实验,对多比特实验过程中应用到的实验技术进行介绍.最后对核磁共振体系多量子比特实验技术方向的进一步研究进行了总结和展望.