定价： 923元 / 折扣价： 785 元

定价： 345元 / 折扣价： 294 元

定价： 345元 / 折扣价： 294 元

定价： 345元 / 折扣价： 294 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 156元 / 折扣价： 133 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

定价： 156元 / 折扣价： 133 元 加购物车

4.1 ZSM-5 is a siliceous zeolite that can be crystallized with SiO2/Al2O3 ratio in the range of 20 to greater than 1000. ZSM-5, upon modification to the H-cation form (HZSM-5) in a post-crystallization step, has been used since the 1970s as a shape selective, acid-site catalyst for petroleum refining and petrochemicals production, including such processes as alkylation, isomerization, fluid cracking catalysis (FCC), and methanol-to-gasoline. The most siliceous member of the ZSM-5 family, sometimes called silicalite, is hydrophobic and it is used for selective sorption of organic molecules from water-containing systems.4.2 This X-ray procedure is designed to allow a reporting of the relative degree of crystallization upon manufacture of ZSM-5. The relative crystallinity/ZSM-5 number has proven useful in technology, research, and specifications.4.3 The Integrated Peak Area Method (Procedure A) is preferred over the Peak Height Method (Procedure B) since it calculates XRD intensity as a sum from several peaks rather than utilizing just one peak. Drastic changes in intensity of individual peaks in the XRD pattern of ZSM-5 can result from changes in distribution of electron density within the unit cell of the ZSM-5 zeolite. The electron density distribution is dependent upon the following factors:4.3.1 Extent of filling of pores with guest molecules and the nature of these guest molecules.4.3.2 Type of cations and extent of their presence (these cations may also affect the absorption of X rays by the ZSM-5 sample).4.3.3 In this XRD method, the guest molecule H2O completes the filling of the pores. Other guest molecule types may also be present, including one of numerous amines, diamines, and quarternary ammonium cations that can function as a template for crystallization of the ZSM-5 structure.4.3.4 Because of the factors mentioned in 4.3.1 to 4.3.3 that could vary the intensities of the XRD peaks in ZSM-5, this XRD method will provide the best determination of relative crystallinity when the reference ZSM-5 and sample ZSM-5 have a similar history of preparation and composition.4.4 ZSM-5 can exist with either orthorhombic or monoclinic symmetry, depending upon the composition of the precursor gel or post-crystallization modification conditions, or both. In the orthorhombic type, the XRD peaks centered at about 23.1 and 23.8° 2θ are usually split into doublets, whereas the less symmetric monoclinic type may show a further split of these peaks into triplets. The peak area intensities of these peaks are unaffected by the crystalline form. The XRD peak at 24.3° 2θ for the orthorhombic form is a singlet and hence is the most suitable for the Peak Height Method (Procedure B). If the 24.3° peak is split (doublet in the monoclinic form), then the Integrated Peak Area Method (Procedure A) should be used.4.5 If crystalline phases other than ZSM-5 are present in the sample, their diffraction peaks may overlap with some of the ZSM-5 peaks selected for the Integrated Peak Area Method (Procedure A). If there is reason to suspect the presence of such components, then the Peak Height Method (Procedure B) should be chosen for analysis provided that there is no interference with the 24.3° 2θ peak that is used for the calculation.1.1 This test method covers a procedure for determination of the relative crystallinity of zeolite ZSM-5 using selected peaks from the X-ray diffraction pattern of the zeolite.1.2 The test method provides a number that is the ratio of intensity of a portion of the XRD pattern of the sample ZSM-5 to intensity of the corresponding portion of the pattern of a reference ZSM-5. The intensity ratio, expressed as a percentage, is then labeled percent XRD relative crystallinity/ZSM-5. This type of comparison is commonly used in zeolite technology and is often referred to as percent crystallinity.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

5.1 Tinting strength is an essential property of printing ink dispersions. Although results on bulk tints do not guarantee equivalency of dry printed films, they provide useful parameters for quality control of production batches of bases and finished inks. Test results may also be used for color matching purposes.1.1 This test method covers the procedure for determining the relative tinting strength of waterbased ink systems using a computer-aided spectrophotometer.1.2 This test method is applicable to waterbased printing inks and bases to be used primarily in flexographic and gravure printing applications.1.3 This test method applies only to single, non-fluorescent pigmented colors and black ink systems for which there is a reference standard containing a pigment of the identical color index name and number.1.4 The procedure in this test method specifies placing tinted samples in a cuvette for spectrophotometric measurements. The use of thick wet drawdowns as in Test Methods D2066 are inappropriate due to severe floating problems with aqueous systems.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 515元 / 折扣价： 438 元 加购物车

定价： 590元 / 折扣价： 502 元 加购物车

定价： 0元 / 折扣价： 0 元 加购物车

4.1 These test methods are intended for use as control and acceptance tests. They are also applicable in the partial evaluation of materials for specific end uses and as a means for detecting changes in materials due to specific deteriorating causes.4.2 The steps involved in running this method are:4.2.1 Calibration of the viscometers,4.2.2 Preparation of solutions,4.2.3 Determination of efflux time,4.2.4 Calculation of relative viscosity (which requires the following),4.2.4.1 Determining the density of the polymer/formic acid solution, and4.2.4.2 Determining the absolute viscosity of the formic acid used.4.3 Solvents used to prepare concentrated solutions for use in this test method are formic acid (9.2.6.1) and m-cresol (9.2.6.2).4.4 Solvents used to prepare dilute solutions of various polyamides are designated in ASTM D6779, ISO 16396, and ISO 307. These include:4.4.1 Formic Acid—PA 6, PA 46, PA 66, PA 69, PA 610, PA MXD6 and corresponding copolyamides4.4.2 Sulfuric Acid—PA 6, PA 46, PA 66, PA 69, PA 610, PA 612, PA MXD6 and corresponding copolyamides4.4.3 m-cresol—PA 612, PA1010, PA1012, PA 11, PA 12, PA1212, PA 11/12 copolymers, PA 6T/66, PA 6I/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/664.4.4 Phenol/1,1,2,2-tetrachloroethane (where legal)—PA 6T/66, PA 6I/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 6I/6T/66, PA 6T/66, PA 6I/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA 10T PA 6I/6T/66, PPA and copolyamides1.1 This test method covers the determination of relative viscosity as it applies to concentrated solutions of polyamide (PA).1.2 This test method does not address measures of viscosity derived from measurements with dilute solutions.1.3 The values stated in SI units are to be regarded as standard. The values given in brackets are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 1: This standard and ISO 307 address the same subject, buy the technical content is different.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

定价： 590元 / 折扣价： 502 元 加购物车