定价： 2197元 / 折扣价： 1956 元 加购物车

定价： 1290元 / 折扣价： 1149 元 加购物车

定价： 1665元 / 折扣价： 1482 元 加购物车

定价： 2081元 / 折扣价： 1853 元 加购物车

定价： 2081元 / 折扣价： 1853 元 加购物车

定价： 2331元 / 折扣价： 2075 元 加购物车

定价： 566元 / 折扣价： 504 元 加购物车

定价： 2081元 / 折扣价： 1853 元 加购物车

This specification covers the material characteristics, physical requirements, and sampling method appropriate to the selection of quartz-based dimension stone for general building and structural purposes. Quartz-based dimension stone shall include stone that is sawed, cut, split, or otherwise finished or shaped, and shall specifically exclude molded, cast, or otherwise artificially aggregated units composed of fragments, and also crushed and broken stone. Quartz stones covered here shall be classified according to the free silica content, as follows: sandstone (I); quartzitic sandstone (II); and quartzite (III) The physical property requirements to which quartz-based stones shall adhere to are absorption by weight, density, compressive strength, modulus of rupture, and abrasion resistance.1.1 This specification covers the material characteristics, physical requirements, and sampling appropriate to the selection of quartz-based dimension stone for general building and structural purposes. Refer to Guides C1242 and C1528 for the appropriate selection and use of quartz-based dimension stone.1.2 Quartz-based dimension stone shall include stone that is sawed, cut, split, or otherwise finished or shaped, and shall specifically exclude molded, cast, or otherwise artificially aggregated units composed of fragments, and also crushed and broken stone.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.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 加购物车

定价： 571元 加购物车

4.1 Corrosion film growth with thicknesses varying from a monolayer of atoms up to 1 μm can readily be measured on a continuous, real-time, in-situ, basis with QCMs.4.2 The test results obtained for this test method are influenced by various factors, including geometrical effects, temperature, humidity, film thickness, film materials, electrode conditions, gases in the corrosion chamber, atmospheric pressure, and so forth. Calibration of coated crystals and instrumentation and reproducible crystal operating conditions are necessary for consistent results.1.1 This test method monitors the reactivity of a gaseous test environment in which metal surfaces (for example, electrical contacts, assembled printed wiring boards, and so forth) and other materials subject to pollutant gas attack undergo accelerated atmospheric corrosion testing. This test method is applicable to the growth of adherent corrosion films whose total corrosion film thickness ranges from a few atomic monolayers to approximately a micrometre.1.2 The test method provides a dynamic, continuous, in-situ, procedure for monitoring the corrosion rate in corrosion chambers; the uniformity of corrosion chambers; and the corrosion rate on different surfaces. Response time in the order of seconds is possible.1.3 With the proper samples, the quartz crystal microbalance (QCM) test method can also be used to monitor the weight loss from a surface as a result of the desorption of surface species (that is, reduction of an oxide in a reducing atmosphere). (Alternative names for QCM are quartz crystal oscillator, piezoelectric crystal oscillator, or thin-film evaporation monitor.)1.4 This test method is not sufficient to specify the corrosion process that may be occurring in a chamber, since a variety of pollutant gases and environments may cause similar weight gains.1.5 This test method is generally not applicable to test environments in which solid or liquid particles are deposited on the surface of the quartz crystal.1.6 The values stated in SI units are to be regarded as standard. The values in parentheses are for information only.1.7 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 become familiar with all hazards including those identified in the appropriate Safety Data Sheet (SDS) for this product/material as provided by the manufacturer, to establish appropriate safety, health, and environmental practices, and determine the applicability of regulatory limitations prior to use.1.8 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 加购物车

定价： 515元 加购物车

定价： 590元 加购物车

4.1 Both sellers and purchasers of alumina and quartz will find the test method useful to determine the specific surface area and indirectly as a measure of the particle size for material specifications, manufacturing control, and research and development.1.1 This test method covers the determination of the specific surface area of aluminas and silicas used in the manufacture of ceramics. The test method is a general one, permitting the use of any modern commercial nitrogen adsorption apparatus but strictly defining the outgassing procedure. Calculations are based on the Brunauer-Emmett-Teller (BET) equation.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.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 加购物车

3.1 The tendency of a jet fuel to resist the formation of deposits at elevated temperature is indicative of its oxidative thermal stability. This practice provides a technique for the simultaneous determination of deposit formation and oxygen consumption during the thermal oxidation of jet fuels and other hydrocarbon liquids. The practice can be used to evaluate the thermal stability of fuels and to determine the efficacy of additives in inhibiting deposition or slowing oxidation, or both. A test temperature of 140 °C and run length up to 16 h has been found to be effective for the relative evaluation of fuels and fuel additives. This practice has also been employed for other hydrocarbon liquids, such as gasoline and diesel fuels, but additional safety issues may need to be addressed by the user.1.1 This laboratory practice covers the quantitative determination of surface deposits produced during the thermal oxidation of gas turbine fuels by monitoring the oscillation frequency of a quartz crystal during thermal exposure. In this practice, “thermal oxidative stability” refers to the tendency of a fuel to resist surface deposit formation during heating.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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： 590元 加购物车