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Measurement of bacterial densities is generally the first step in establishing a relationship between bacteria and other biochemical processes. It is known that the classical plate count procedure underestimates bacterial densities while the epifluorescence direct microscopic procedure more accurately depicts the total numbers of nonviable or dormant and viable cells in a water sample. The acridine-orange INT-formazan reduction technique provides information on the total concentrations of bacteria as well as that proportion which are actively respiring and thus involved in degradative processes.The acridine-orange INT-formazan reduction technique is both quantitative and precise.This procedure is ideal for enumerating both pelagic and epibenthic bacteria in all fresh water and marine environments.The process can be employed in survey studies to characterize the bacteriological densities and activities of environmental waters.1.1 This test method covers the detection and enumeration of aquatic bacteria by the use of an acridine-orange epifluorescence direct-microscopic counting procedure. This test method is applicable to environmental waters and potable waters.1.2 Certain types of debris and other microorganisms may fluoresce in acridine-orange stained smears.1.3 The procedure described requires a trained microbiologist or technician who is capable of distinguishing bacteria from other fluorescing bodies on the basis of morphology when viewed at higher magnifications.1.4 Use of bright light permits differentiation of single bacteria where reduced formazan is deposited at the polar ends.1.5 Approximately 104 cells/mL are required for detection by this test method.1.6 Minimal cell size which allows the detection of formazan deposits is represented by bacteria of 0.4 μm.21.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.8 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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定价： 345元 / 折扣价： 294 元 加购物车

4.1 The ability of a multilayer nickel deposit to enhance corrosion resistance is a function of the difference in the electrode potentials of the nickel layers (as measured individually at a fixed current density in a given electrolyte versus a reference electrode) and the thicknesses of the layers. The potential differences must be sufficient to cause the bright nickel or top layer to corrode preferentially and sacrificially with respect to the semi-bright nickel layer beneath it.4.2 This test procedure allows the measurement of these potential differences directly on an electroplated part rather than on separate foil specimens in such a way that time determines the thickness of each layer, while the potential difference between nickel layers is an indication of the corrosion resistance of the total nickel deposit.4.3 The interpretation and evaluation of the results of this test should be by agreement between the purchaser and the manufacturer.NOTE 1: This test may be used as a quality assurance test of the multilayer nickel coatings applied in production. It should be understood that due to many factors that influence the progress of corrosion during actual use of the part, the performance of different multilayer nickel deposits in the test cannot be taken as an absolute indicator of the relative corrosion resistance of these deposits in service.1.1 This test method closely estimates the thickness of individual layers of a multilayer nickel electrodeposit and the potential differences between the individual layers while being anodically stripped at constant current density.2,31.2 This test method does not cover deposit systems other than multilayer electroplated nickel deposits.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 / 折扣价： 502 元 加购物车

This test method of applying force may be used as a standard test to compare the characteristics of a given design of container/child-resistant closure system with a standard or to compare the characteristics of container/child-resistant closure systems differing in construction.It may be used to simulate certain manipulations that may be expected to occur in protocol testing (such as, prying with the teeth or objects in the room, biting, and pulling with the teeth).This test method may be used to establish performance specifications.1.1 This test method covers the measurement of the force required to separate (or “shell”) the snap-fitted outer cap from the inner cap of Type IA, IB, or IC child-resistant closures.1.2 This test method does not measure the force required to separate parts of a child-resistant closure system that were originally “screwed-on” instead of “snapped-on” (for example, pull a cap over or through continuous or multi-start threads when the cap was originally screwed on).1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses 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 and health practices and determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元

This test method of applying force may be used as a standard test to compare the characteristics of a given design of container/child-resistant closure system with a standard or to compare the characteristics of container/child resistant closure systems differing in construction.It may be used to simulate certain manipulations that may be expected to occur in protocol testing (such as, prying with the teeth, or objects in the room, biting, and pulling with the teeth).This test may be used to establish performance specifications. Shelling force may vary with cap application torque, bottle design, and other factors. Consequently where precise comparative results are desired, these factors must be carefully controlled.1.1 This test method covers the measurement of the force required to separate (or “shell”) the snap-fitted outer cap from the inner cap of Type IA, IB, or IC child-resistant closures. See Practice D3475.1.2 This test method is an alternative to Test Method D3481, a manual test procedure.1.3 This test method does not measure the force required to separate parts of a child-resistant closure system that were originally “screwed-on” instead of “snapped-on” (for example, pull a cap over or through continuous or multi-start threads when the cap was originally screwed on).1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.

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定价： 525元 / 折扣价： 468 元 加购物车

定价： 799元 / 折扣价： 712 元 加购物车

定价： 525元 / 折扣价： 468 元 加购物车

定价： 525元 / 折扣价： 468 元 加购物车