定价： 156元 / 折扣价： 133 元 加购物车

定价： 78元 / 折扣价： 67 元 加购物车

定价： 280元 / 折扣价： 238 元 加购物车

定价： 689元 / 折扣价： 586 元 加购物车

定价： 481元 / 折扣价： 409 元 加购物车

定价： 1768元 / 折扣价： 1503 元

5.1 For ferromagnetic materials, magnetic particle examination is widely specified for the detection of surface and near-surface flaws such as cracks, laps, seams, and linearly oriented nonmetallic inclusions. Such examinations are included as mandatory requirements in some forging standards such as Specifications A508/A508M and A963/A963M.5.2 Use of alternating current as the power source for magnetic particle examination imposes a significant restriction on the detection of subsurface indications, so that the procedure is essentially limited to the finding of flaws that are open to the surface. Attention therefore is drawn to the need to have the component in the finish-machined condition before conducting the magnetic particle examination.5.3 The presence of residual magnetic fields in a component may be undesirable, and an advantage of the use of an ac power source for magnetic particle examination is that an acceptable level of demagnetization can be readily achieved.1.1 This practice covers a procedure for the magnetic particle examination of steel forgings using alternating current as the power source. The procedure will produce consistent results upon which acceptance standards can be based. This practice does not contain acceptance limits or recommended quality levels.1.2 Only alternating 50–60 cycle current shall be used as the electric power source for any of the magnetizing methods.1.3 When subsurface indications are sought in forgings, then dc magnetization in accordance with Practice A275/A275M should be used.1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. Unless the order specifies the applicable “M” specification designation [SI units], the inch-pound units shall be used.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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 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

1. Scope 1.1 This Standard applies only to gapless metal oxide surge arresters of separate mounting or those supplied integrally with other equipment. The surge arresters are designed to limit voltage surges in 50 or 60 Hz alternating current power ci

定价： 455元 / 折扣价： 387 元

5.1 This test method was developed for evaluating the ac magnetic properties of laminated cores made from flat-rolled magnetic materials.5.2 The reproducibility and repeatability of this test method are such that this test method is suitable for design, specification acceptance, service evaluation, and research and development.1.1 This test method covers the determination of several ac magnetic properties of laminated cores made from flat-rolled magnetic materials.1.2 This test method covers test equipment and procedures for the determination of impedance permeability and exciting power from voltage and current measurements, and core loss from wattmeter measurements. These tests are made under conditions of sinusoidal flux.1.3 This test method covers tests for two general categories (1 and 2) of cores based on size and application.1.4 Tests are provided for power and control size cores (Category 1) operating at inductions of 10 to 15 kG [1.0 to 1.5 T] and at frequencies of 50, 60, and 400 Hz.1.5 Procedures and tests are provided for coupling and matching type transformer cores (Category 2) over the range of inductions from 100 G [0.01 T] or lower to 10 kG [1.0 T] and above at 50 to 60 Hz or above when covered by suitable procurement specifications.1.6 This test method also covers tests for core loss and ac impedance permeability under incremental test conditions (ac magnetization superimposed on dc magnetization) for the above core types and at inductions up to those that cause the ac exciting current to become excessively distorted or reach values that exceed the limits of the individual test equipment components.1.7 This test method shall be used in conjunction with Practice A34/A34M and Terminology A340. It depends upon these designated documents for detailed information which will not be repeated in this test method.1.8 The values and equations stated in customary (cgs-emu and inch-pound) or SI units are to be regarded separately as standard. Within this standard, SI units are shown in brackets. 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 nonconformance with this standard.1.9 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.1.10 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： 646元 / 折扣价： 550 元 加购物车

5.1 The electrical properties of gate and field oxides are altered by ionizing radiation. The method for determining the dose delivered by the source irradiation is discussed in Practices E666, E668, E1249, and Guide E1894. The time dependent and dose rate effects of the ionizing radiation can be determined by comparing pre- and post-irradiation voltage shifts, ΔVot and ΔVit. This test method provides a means for evaluation of the ionizing radiation response of MOSFETs and isolation parasitic MOSFETs.5.2 The measured voltage shifts, ΔVot and ΔVit, can provide a measure of the effectiveness of processing variations on the ionizing radiation response.5.3 This technique can be used to monitor the total-dose response of a process technology.1.1 This test method covers the use of the subthreshold charge separation technique for analysis of ionizing radiation degradation of a gate dielectric in a metal-oxide-semiconductor-field-effect transistor (MOSFET) and an isolation dielectric in a parasitic MOSFET.2,3,4 The subthreshold technique is used to separate the ionizing radiation-induced inversion voltage shift, ΔVINV into voltage shifts due to oxide trapped charge, ΔVot and interface traps, ΔV it. This technique uses the pre- and post-irradiation drain to source current versus gate voltage characteristics in the MOSFET subthreshold region.1.2 Procedures are given for measuring the MOSFET subthreshold current-voltage characteristics and for the calculation of results.1.3 The application of this test method requires the MOSFET to have a substrate (body) contact.1.4 Both pre- and post-irradiation MOSFET subthreshold source or drain curves must follow an exponential dependence on gate voltage for a minimum of two decades of current.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： 0元 / 折扣价： 0 元

1. Scope 1.1 This Standard covers single-phase, ac electrical installations not exceeding 250 V between conductors or 150 V to ground, on boats which may have an on-board source of electrical supply or may be connected to a source of ac electrical sup

定价： 455元 / 折扣价： 387 元

定价： 1866元 / 折扣价： 1587 元

Unsaturated sink current is a special parameter that is closely related to the gain of the output transistor of TTL circuits. This parameter is particularly useful in evaluating neutron degradation in TTL devices because it changes smoothly as the device degrades, and exhibits larger changes at moderate radiation levels than the standard electrical parameters.1.1 This test method covers the measurement of the unsaturated sink current of transistor-transistor logic (TTL) devices under specified conditions.1.2 Units—The values stated in the International System of Units (SI) 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 and health practices and determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元

定价： 1638元 / 折扣价： 1393 元

5.1 The purpose of the alternating current field measurement method is to evaluate threads for surface breaking discontinuities such as fatigue cracks running along the thread root. The examination results may then be used to determine the fate of the test piece. This may involve re-examination by an alternative technique, immediate scrapping of the test piece, or reworking to remove discontinuities (beyond the scope of this practice). This practice is not intended for the examination of threads for non-surface breaking discontinuities.1.1 This practice describes procedures to be followed during alternating current field measurement examination of drillstring threads on tubulars used for oil and gas exploration and production for detection and, if required, sizing of service-induced surface breaking discontinuities transverse to the pipe.1.2 This practice is intended for use on threads in any metallic material.1.3 This practice does not establish acceptance criteria. Typical industry practice is to reject these connections on detection of a confirmed crack.1.4 While the alternating current field measurement technique is capable of detecting discontinuities in these connections, supplemental surface NDT methods such as magnetic particle testing for ferrous metals and penetrant testing for non-ferrous metals may detect additional discontinuities.1.5 Units—The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system might not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from both systems may result in nonconformance with the 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： 590元 / 折扣价： 502 元 加购物车