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PHÁT TRIỂN NĂNG LỰC TẠO LẬP VĂN BẢN THUYẾT MINH CHO HỌC SINH THÔNG QUA PHÂN TÍCH MẪU TRONG DẠY ĐỌC HIỂU Nguyễn Thị Hồng Hạnh 1* và Đỗ Thanh An 2. Dạy đọc hiểu, dạy tạo lập, năng lực tạo lập, phân tích mẫu, văn bản thuyết minh Keywords:. Để tạo lập được một loại văn bản nào đó,...
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T m quan tr ng ầ ọ. Logo hay còn g i là bi u tr ng là nh ng tín hi u, ký hi u có ch c năng thông tin đ bi u hi n m t đ i t ọ ể ư ữ ệ ệ ứ ể ể ệ ộ ố ượ ng ho c m t...
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see also Selectivity. see also Multidimensional HPLC;. see also. see also DryLab. see Detectors,. see Detectors, conductivity. see Detectors, charged-aerosol. see also Data. see also Error, sources. see also Sample. see also Calibration, limits. see also Calibration,. see Detectors, UV. see also Computer-simulation software gradient optimization, 483–485 isocratic predictions from gradient data,. see also Dwell volume Dwell volume . see...
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INTRODUCTION TO MODERN LIQUID. A John Wiley &. Sons, Inc., Publication. Copyright © 2010 by John Wiley &. Sons, Inc. Published by John Wiley &. Sons, Inc., Hoboken, New Jersey.. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except...
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3.6.4.1 Column Switching Fraction Collectors Waste Diversion, 124 3.7 Column Ovens, 125. 3.10.1 System-Performance Tests Installation Qualification,. 3.10.2 Preventive Maintenance, 138. 3.10.2.1 Periodic Maintenance Suggestions for Routine. 3.10.3.1 Personnel Record Keeping Specific Repair. 4.9 Chemiluminescent Nitrogen Detector, 174 4.10 Chiral Detectors, 175. 5.1 Introduction, 200 5.2 Column Supports, 200. 5.3.3 Column Functionality (Ligand Type), 225 5.4 Column Selectivity, 227. 5.4.4.3...
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with Michael Swartz 12.1 Introduction, 532. 12.2 Terms and Definitions Accuracy Precision, 536. 12.2.2.1 Repeatability, 536. 12.2.2.2 Intermediate Precision Reproducibility, 537. 12.2.2.4 Ruggedness Specificity, 539. 12.2.4 Limit of Detection and Limit of Quantification, 539. 12.2.5 Linearity and Range Robustness, 540. 12.3 System Suitability, 542 12.4 Documentation, 543. 12.4.1 Validation Protocol Test Method Validation Report, 545. 12.5 Validation for Different Pharmaceutical-Method...
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17.3.5 Module Substitution Put It Back, 821. 17.4 Common Symptoms of HPLC Problems Leaks, 822. 17.4.1.1 Pre-pump Leaks Pump Leaks, 823. 17.4.1.3 High-Pressure Leaks Autosampler Leaks Column Leaks Detector Leaks Abnormal Pressure, 830. 17.4.2.1 Pressure Too High Pressure Too Low Pressure Too Variable Variation in Retention Time, 833. 17.4.3.1 Flow-Rate Problems Column-Size Problems Mobile-Phase Problems Stationary-Phase Problems Temperature Problems Retention-Problem....
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Figure 2.16a AU absorbance units (UV detection). Equation (9.4) B column hydrogen-bond basicity. CEC capillary electrochromatography CCC countercurrent chromatography CLND chemiluminescent nitrogen detector C m solute concentration in mobile phase CMPA chiral mobile-phase additive. Equation (2.19) DMSO dimethylsulfoxide. F opt optimum mobile-phase flow rate (mL/min) (Section 2.4.1) F s column-comparison function. Equation (6.3) G gradient compression factor. Equation (9.15a) H...
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Figure 1.4 Recent examples of HPLC capability. (a) Fast separation of six proteins, using gra- dient elution with a 150 × 4.6-mm column packed with 1.5-μm-diameter pellicular particles [5]. (b) initial separation of peptides and proteins from human fetal fibroblast cell by gradi- ent cation-exchange chromatography. (c) further separation of fraction 7 (collected between 24–28 min) on a second column...
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Zlatkis, eds., 75 years of Chromatography—A Historical Dialog, Elsevier, Amsterdam, 1979.. Gehrke, ed., Chromatography—A Century of Discovery Elsevier, Amsterdam, 2001.. 81), Dekker, New York, 1999.. BASIC CONCEPTS AND THE CONTROL OF SEPARATION. 2.3.2 Role of Separation Conditions and Sample Composition, 28 2.4 PEAK WIDTH AND THE COLUMN PLATE NUMBER N, 35. 2.5.3 Optimizing the Column Plate Number N, 61 2.5.4...
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where K = (C s /C m ) is the equilibrium constant for Equation (2.2), and = (V s /V m ) is the phase ratio—the ratio of stationary and mobile-phase volumes within the column. values of k can help us interpret and improve the quality of a separation. A solute molecule must be present in either the mobile or...
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Figure 2.10 Origin and measurement of peak width. (b) peak 3 of Figure 2.6 as a function of %B, shown with the same time scale for each peak.. Because an ideal chromatographic peak has the shape of a Gaussian curve (Section 2.4.2), peak width is sometimes described in terms of the standard deviation σ of the Gaussian curve, where. (2.9c)...
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Figure 2.13 Knox equation. (a) Plot of reduced plate height h versus reduced velocity ν with A = 1, B = 2, and C = 0.05. All plots based on Equation (2.17) with A = 1, B = 2, and C = 0.05.. Column conditions can be defined as column length and diameter, particle size, and flow rate. Together these...
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Figure 2.18 Separation as a function of mobile phase %B. methanol-water mixtures as mobile phase. a shorter run time.. However, the term ‘‘optimized’’ is often used in the literature to indicate a relatively improved or preferred separation rather than an absolute best separation.. We will continue this usage in the present book. Sample retention k in isocratic elution is usually...
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present, it will be necessary to add a buffer to the mobile phase so as to control its pH. pK a values for sample compounds, if available, can be useful during method development (Chapter 7). The molecular weight of the sample may also affect the choice of separation conditions for initial experiments (Sections . Depending on the equipment that is...
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Gradient elution refers to a continuous change in the mobile phase during separation, such that the retention of later peaks is continually reduced. An illustration of the power of gradient elution is shown in Figure 2.25c, where all peaks for the sample of Figure 2.25a, b are separated to baseline in a total run time of slightly more than 7...
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3.2.2 Mobile-Phase Filtration, 91 3.3 MOBILE-PHASE DEGASSING, 92. Today there is less distinction between HPLC systems than in the past, and it can be safely said that there are no ‘‘bad’’ HPLC systems currently on the market. Users in the past often would select specific equipment modules from different vendors and, in a mix-and-match approach, would design their own ‘‘ideal’’...
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If reasonable care is taken in the selection and use of tubing and fittings, problems will seldom be encountered. Note that the following discussion refers to the dimensions and thread sizes of tubing and fittings in English units (usually fractional or decimal inches), because this is the way they are commonly supplied in the United States.. 3.4.1.1 Low-Pressure Tubing. The...
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Figure 3.12 Check-valve designs. Operation of the ball-type check valve is quite simple. When the pressure on the inlet side of the valve (below the ball in Fig. 3.12a) is higher than that on the outlet side, the ball will be displaced from the seat and solvent will flow through the valve. As described above, and illustrated in Figure 3.11,...
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Figure 3.19 Effect of laminar flow on injection accuracy. (b) laminar flow profile of sample. ≥200% of the loop volume for maximum accuracy.. Injection-volume accuracy may fall short of this level because of errors in calibration of the sample syringe or injection loop.. Usually the precision of injection is more important than accuracy because of the compensating use of standards...