TLC-SERS联用法检测降糖中成药中添加的格列类药品

目的：研究降糖中成药中非法添加格列类药品的表面增强拉曼光谱（ surface enhanced Raman spectroscopy , SERS）检测方法。方法利用薄层色谱法将待检成分与中药基质进行简单分离,采用表面增强拉曼光谱技术对薄层板上的微量物质进行检测。通过摸索模拟阳性样品中格列类药品的SERS检测条件,建立可用于降糖中成药中非法添加物的检测方法。结果采用有机溶剂DMF制备所得的银溶胶可以获得较好的格列类药物SERS图谱。结论该研究所建立的TLC与SERS联用方法检测简便、快速、经济,可用于降糖中成药中非法添加格列类药品的快速检测。     

采用响应面法优化替考拉宁的层析工艺

目的对替考拉宁的层析提取工艺进行优化。方法通过对层析用树脂的筛选和单因素试验,分别考察了上样pH值、洗脱液pH、洗脱液乙醇浓度等对替考拉宁提取比的影响,确定各因素的适宜水平。在此基础上,使用Box—Behnken法通过Design—Expert软件设计响应面试验,寻找最优条件。结果替考拉宁的最佳提取工艺条件为：上样pH6．45、洗脱液pH8．00、洗脱液乙醇浓度59％。在此条件下,替考拉宁的提取比为0．9487。结论经优化,替考拉宁分离纯化的提取比提高了10．23％,产品色素符合《中国药典》的要求。     

替比夫定联合阿德福韦酯治疗慢性乙型肝炎的临床观察

目的：探讨替比夫定联合阿德福韦酯治疗慢性乙型肝炎的疗效。方法选择2O1O 年3月-2O12年3月于本院就诊的 HBsAg 阳性慢性乙型肝炎患者75例,将其随机分为两组。对照组35例患者采用替比夫定1OOmg/ d 治疗,研究组4O 例患者采用替比夫定联合阿德福韦酯治疗。分别观察治疗12、24、36、48周后 HBsAg 转阴率和肝功能等各项指标。结果两组患者治疗后12、24周,HBV - DNA 与 HBsAg 转阴例数比较,差异无统计学意义（ P 〉O. O5）,治疗后36、48周两组比较差异有统计学意义（P 〈 O. O5）。两组患者治疗前 AST、ALT、总胆红素（TBIL）、HBV - DNA 比差异无统计学意义（P〉 O. O5）,治疗后研究组小于对照组,差异有统计学意义（P 〈 O. O5）。结论替比夫定与阿德福韦酯联合使用治疗慢性乙型肝炎疗效优于单用替比夫定,适宜临床推广。     

星点设计–效应面法优化川芎提取工艺

目的 采用星点设计效应面法优化川芎中阿魏酸和藁本内酯的提取工艺。方法 以川芎药材中阿魏酸、藁本内酯的质量分数为考察指标,考察乙醇体积分数、提取温度以及提取时间对提取工艺的影响,对结果进行二项式拟合,用效应面法选择较佳工艺条件,并进行预测分析。结果 确定较优提取工艺为83 ℃下,14倍量73%乙醇提取2次,每次2 h,含量实际值与预测值偏差为?1.37%。结论 星点设计效应面法优化川芎提取工艺,方法简便,结果可靠,预测性良好。     

Establishing the Relationship between Cutting Speed and Output Parameters in Belt Grinding on Steels,Aluminum and Nickel Alloys: Development of Recommendations

This paper presents the research results of one of the main technological parameters of belt grinding, i.e., the cutting speed while machining corrosion- and heat-resistant, structural carbon and structural alloy steels, aluminum, and heat-resistant nickel alloys. Experimental and analytical methods are used to establish the dependence of the output parameters of surface belt grinding on the cutting speed and tool characteristics. An analytical model, considering the physical and mechanical properties of the grinding belt (strength depending on the base and bond; the thermal conductivity; the type of grinding operation) and the machined material, is created to determine the belt grinding speed. The output parameters, such as the arithmetic mean of the surface roughness (Ra) and the material removal rate (MRR) during the belt grinding of steels, heat-resistant and light alloys, have been studied. Based on the empirical dependencies of the belt grinding parameters, the model was developed for the selection and setting of the cutting speed of belt grinding for the aforementioned alloys, taking into account the type of operation, the type of the machined material, and the main characteristics of the sanding belt.     

Electrochemical Activity and Damage of Single Carbon Fiber

The electrochemical activity of a carbon fiber was characterized at different potentials in 3.5 wt.% NaCl solution, and the fiber cylindrical surface changed by polarization at different potentials was revealed by SEM, AFM, optical microscopy, FTIR spectroscopy, Raman spectroscopy, and XRD. The results showed that the carbon fiber exhibited different electrochemical activities at some polarization potentials; within a 3V potential range the anodic and cathodic polarization current densities stepped up by more than 5 orders of magnitude, and the carbon fiber (CF) surface dramatically changed with time. Strong anodic polarization appeared to facilitate the breakdown of C-C covalent bonds in the carbon fiber and enhance the amorphization of the fiber surface.     

Optimisation of Shrinkage and Strength on Thick Plate Part Using Recycled LDPE Materials

Achieving good quality of products from plastic injection moulding processes is very challenging, since the process comprises many affecting parameters. Common defects such as warpage are hard to avoid, and the defective parts will eventually go to waste, leading to unnecessary costs to the manufacturer. The use of recycled material from postindustrial waste has been studied by a few researchers. However, the application of an optimisation method by which to optimise processing parameters to mould parts using recycled materials remains lacking. In this study, Response Surface Methodology (RSM) and Particle Swarm Optimisation (PSO) methods were conducted on thick plate parts moulded using virgin and recycled low-density polyethylene (LDPE) materials (100:0, 70:30, 60:40 and 50:50; virgin to recycle material ratios) to find the optimal input parameters for each of the material ratios. Shrinkage in the x and y directions increased in correlation with the recycled ratio, compared to virgin material. Meanwhile, the tensile strength of the thick plate part continued to decrease when the recycled ratio increased. R30 (70:30) had the optimum shrinkage in the x direction with respect to R0 (100:0) material where the shrinkage increased by 24.49% (RSM) and 33.20% (PSO). On the other hand, the shrinkage in the y direction for R30 material increased by 4.48% (RSM) and decreased by 2.67% (PSO), while the tensile strength of R30 (70:30) material decreased by 0.51% (RSM) and 2.68% (PSO) as compared to R0 (100:0) material. Validation tests indicated that the optimal setting of processing parameter suggested by PSO and RSM for R0 (100:0), R30 (70:30), R40 (60:40) and R50 (50:50) was less than 10%.     

Effects of Deposition Strategy and Preheating Temperature on Thermo-Mechanical Characteristics of Inconel 718 Super-Alloy Deposited on AISI 1045 Substrate Using a DED Process

Thermomechanical characteristics are highly dependent on the deposition strategy of the directed energy deposition (DED) process, including the deposition path, the interpass time, the deposition volume, etc., as well as the preheating condition of the substrate. This paper aims to investigate the effects of the deposition strategy and the preheating temperature on thermomechanical characteristics of Inconel 718 super-alloy deposited on an AISI 1045 substrate using a DED process via finite element analyses (FEAs). FE models for different deposition strategies and preheating temperatures are created to examine the thermomechanical behavior. Sixteen deposition strategies are adopted to perform FEAs. The heat sink coefficient is estimated from a comparison of temperature histories of experiments and those of FEAs to obtain appropriate FE models. The influence of deposition strategies on residual stress distributions in the designed model for a small volume deposition is examined to determine feasible deposition strategies. In addition, the effects of the deposition strategy and the preheating temperature on residual stress distributions of the designed part for large volume deposition are investigated to predict a suitable deposition strategy of the DED head and appropriate preheating temperature of the substrate.     

Revealing the WEDM Process Parameters for the Machining of Pure and Heat-Treated Titanium (Ti-6Al-4V) Alloy

Ti-6Al-4V is an alloy that has a high strength-to-weight ratio. It is known as an alpha-beta titanium alloy with excellent corrosion resistance. This alloy has a wide range of applications, e.g., in the aerospace and biomedical industries. Examples of alpha stabilizers are aluminum, oxygen, nitrogen, and carbon, which are added to titanium. Examples of beta stabilizers are titanium–iron, titanium–chromium, and titanium–manganese. Despite the exceptional properties, the processing of this titanium alloy is challenging when using conventional methods as it is quite a hard and tough material. Nonconventional methods are required to create intricate and complex geometries, which are difficult with the traditional methods. The present study focused on machining Ti-6Al-4V using wire electrical discharge machining (WEDM) and conducting numerous experiments to establish the machining parameters. The optimal setting of the machining parameters was predicted using a multiresponse optimization technique. Experiments were planned using the response surface methodology (RSM) technique and analysis of variance (ANOVA) was used to determine the significance and contribution of the input parameters to changes in the output characteristics (cutting speed and surface roughness). The cutting speed obtained during the processing of the annealed titanium alloy using WEDM was quite large as compared to the cutting speed obtained in the case of processing the pure, quenched, and hardened titanium alloys using WEDM. The maximum cutting speed obtained while processing the annealed titanium alloy was 1.75 mm/min.     

Effects of Machined Surface Integrity on High-Temperature Low-Cycle Fatigue Life and Process Parameters Optimization of Turning Superalloy Inconel 718

Machined surface integrity characteristics, including surface stresses, physical-mechanical properties and metallographic structures, play important roles in the fatigue performance of machined components. This work aimed at investigating the effects of machined surface integrity on high-temperature low-cycle fatigue life. The process parameters were optimized to obtain required surface integrity and fatigue life of the turning superalloy Inconel 718. The relationships between low-cycle fatigue life and machined surface integrity characterization parameters were established based on the low-cycle fatigue tests at a high temperature (650 °C). The sensitivities of turning process parameters to high-temperature low-cycle fatigue life were analyzed, and the optimization parameters were proposed with the goal of antifatigue manufacturing. Experimental results indicated that the impact order of the characterization parameters of machined surface integrity on the high-temperature low-cycle fatigue life were the degree of work hardening R_HV, the residual stress in the cutting speed direction S₂₂, the fatigue stress concentration factor K_f, the degree of grain refinement R_D and the residual stress in the feed direction S₃₃. In the range of turning parameters of the experiments in this research, the cutting speeds could be 80~110 m/min, and the feed rate could be 0.10~0.12 mm/rev to achieve a longer high-temperature low-cycle fatigue life. The results can be used for guiding the fatigue-resistant manufacturing research of aeroengine superalloy turbine disks.