主要成分

By reducing its dimensions through matrix conversion using the algorithm, the fault feature of condensator in the marine propulsion plant was extracted.

详细介绍了一种特征提取方法—主成分分析方法，运用该方法，经过矩阵变换、降低维数以提取故障信息的主要特征，实现了对船舶动力装置冷凝器的故障特征提取，为船舶动力装置冷凝器故障诊断及故障预报问题提供了一种有效可行的数据预处理方式

Firstly, this paper investigated roundly the basic theory of the ambient vibration method, analyzed systematically the main methods of ambient vibration identification, and discussed their advantages and disadvantages. Then we established the finite element model of structural dynamics and test model and analyzed their mutual relation, improved MUSIC method and correlation function method in the harmonic identification, and gave the subspace method and correlation function method based on continuous model, which is multi-harmonic retrieve technique. And then, this paper also puts forward least-squares method to estimate directly structural physical and modal parameters; this approach replaced the derivative operator in the continuous time model with an equivalent approximation, and estimated the physical parameters of structures by the least-squares method. And then, we discussed the approximation methods of derivative and their convergence. Finally, this paper researched the modal parameters of a frame structure by the simulation and test. The results demonstrated that subspace method, correlation function method and the least-squares method are effective and stable respectively.

全面地研究环境振动识别方法的基本理论，系统地分析环境振动识别方法的主要方法，讨论它们的优点和不足；建立结(来源：6666AB44C论文网www.abclunwen.com)构动力学的有限元模型和试验模型，分析有限元模型与试验模型之间的相互关系；改进谐波识别中的MUSIC识别方法和相关函数识别方法，给出大型结构模态识别的连续型的子空间分解识别方法和相关函数识别方法，这个方法是多元谐波识别方法；提出直接识别结构的物理参数和模态参数的最小二乘方法，这个方法利用导数的近似值代替导数值，并运用最小二乘方法识别结构的物理参数，讨论导数近似值的选择方法，分析算法的收敛性；通过仿真计算和模型实验，研究高层框架结构的模态参数识别，验证子空间分解识别方法、相关函数识别方法和最小二乘识别方法的有效性，算法的稳定性；从理论和试验两个方面分析和研究噪声对识别精度的影响，影响识别精度的因素，以及部分模态成分的模态参数不能够被识别的原因。

Objective:To establish a method for the determination of berberine hydrochloride in Cortex Phellodendri in Compound Gangsong Lotion, for a better controlment of the product quality.

目的：对复方岗松洗液的主药黄柏的主要有效成分盐酸小檗碱进行含量测定，以便更好地控制产品质量。

The mainly contents include: the research design of statistical survey, survey methods, the statistical sorting and analysis of information (contingency table, correlation measurement, inferential statistics, regression analysis, variance analysis, cluster analysis, factor analysis, principal component analysis), the composing of investigation report and the appliance of SPSS.

课程对社会统计和社会调查研究方法进行全面的介绍，要求学生牢固掌握社会统计和社会调查的基本研究方法，能熟练运用社会统计和社会调查的方法和技术从事社会研究工作，对社会统计学的概念和术语有一般程度的掌握，能应用SPSS软件进行社会统计和调查工作。本课程主要内容包括：统计调查的研究设计、资料的调查方法、资料的整理与统计分析方法（列联表、相关关系测度、推断统计、回归分析、方差分析、聚类分析、因子分析、主成分分析等）、撰写调查报告、SPSS应用等。

An investigation of isolation of major active components of coumarin from Angelica pubescens was conducted according to the requirement of the quality evaluation of AP.

根据独活质量评价的需要，对该药香豆素化合物中的主要活性成分进行分离研究。

The treatment of tea candy, basically be the device that uses candied industry and craft, the union such as the active ingredient that tea extraction comes out and candy, grandma, fruit juice, chocolate, amylaceous, vitamin and the plant additive that contain sanitarian sex each is together, form distinctive local color, when making people is in those who enjoy delicate candy can the flavor of savor tea, have certain sanitarian effect at the same time.

茶糖的加工，主要是利用糖果工业的设备和工艺，将茶叶提取出来的有效成分与糖。奶。果汁。巧克力。淀粉。维生素和各带有保健性的植物添加剂等结合在一起，形成独特的风味，使人们在享受美味糖果的时又能尝到茶叶的滋味，同时具有一定的保健作用。

The bioaerosols are at the highest levels during the lunch time period. With either the impactor method or the sedimentation method, one of the major contributing factors is the crowdedness due to many students all at lunch at the same time.

主成分分析结果发现，无论是冲击式采样法或自然沉降法，用餐状态为影响学生餐厅空气中微生物含量的主要因子。

Each cultivar has its own internal quality,and it is affected by many factors.

药用菊花的主要化学成分组成体现了我国药用菊花的多样性，其内在质量受多种因素影响。

The main differences in chemical compounds related to the taste and flavorbetween cultured and wild prawns may be summerized as follows: 1 The content of quaternary bases in the extractives of wild prawn is higher than that of cultured prawn; 2 The content of fatty acids, C18:2ω6 is higher in the cultured prawn; 3 Many thiazole compounds were found in the odor concentrate of cultured prawn, azulene was found in the odor compounds of wild prawn; 4 The textrue of cultrued prawn meat is relatively weak.

综上所述，养殖对虾与天然对虾的尝味比较中主要差别是提取物组分的有机碱；对虾肌肉脂质比较结果是养殖对虾肌肉脂质中C18：2ω6含量特别高；对虾挥发性成分结果是养殖对虾中有大量的噻唑化合物，天然对虾存在薁类化合物；两类对虾质地比较的结果是养殖对虾质地不及天然对虾。

It was found that the chemical composition of glass,superheating temperature and the degasification in alloys and glass primarily influenced undercoolings of bulk liquid alloys.

研究结果表明，净化玻璃的化学成分、循环过热温度及净化过程中熔融玻璃和合金液的良好排气条件影响净化效果的主要因素。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。