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定价： 元 加购物车

定价： 元 加购物车

定价： 元 加购物车

1.1 This test method covers the determination of heat of fusion and heat of crystallization of polymers by differential scanning calorimetry. 1.2 This test method is applicable to polymers in granular form (below 60 mesh preferred, avoid grinding if possible) or to any fabricated shape from which appropriate samples can be cut. 1.3 The normal operating temperature range is from the cryogenic region to 600°C. 1.4 The values in SI units are to be regarded as the standard. Note 1-True heats of fusion can only be determined in conjunction with structure investigation and frequently specialized crystallization techniques are needed. Note 2-This test method may not be applicable to all types of polymers as written (see 6.6). Note 3-Uncertain radiation losses at temperatures higher than 400°C may affect the accuracy of results. Note 4- To date, there is no similar or equivalent approved ISO standard. 1.5 This standard may involve hazardous materials, operations, and equipment. 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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1.1 These test methods cover the determination of the nitrogen surface area of carbon blacks by the conventional Brunauer, Emmett, and Teller (B.E.T.) theory of multilayer gas adsorption behavior using multipoint determinations. These test methods specify the sample preparation and treatment, instrument calibrations, required accuracy and precision of experimental data, and calculations of the surface area results from the obtained data. 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 and health practices and determine the applicability of regulatory limitations prior to use. (The minimum safety equipment should include protective gloves, sturdy eye and face protection, and means to deal with accidental mercury spills.)

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In the development of rubber compounds for use in applications where ozone cracking is objectionable, it is necessary to have a test in which simple comparative performance for resistance to cracking can be evaluated. This test method can be used for this performance comparison. This test method is not suited for use in purchase specifications, not only because correlation with service life is uncertain, but because the results from duplicate specimens tested in different locations do not ordinarily give the same values. No exact relation between the results of the test and actual service performance is given or implied. The test is principally of value when used for comparisons between two or more rubber compounds. METHOD A—EXPOSURE OF STRAIGHT SPECIMENS Top 1.1 This test method covers three test specimen procedures that estimate the comparative ability of rubber compounds to withstand the effects of normal weathering, or exposure in an atmosphere containing controlled amounts of ozone. It does not apply to testing of electrical insulation or other rubber parts where high concentrations of ozone prevail due to electrical discharge, nor to testing of material ordinarily classified as hard rubber. 1.2 The values stated in SI units are to be regarded as the 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.

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1.1 These test methods cover the determination of the external surface area of carbon blacks by the statistical thickness surface area (STSA) method. 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 and health practices and determine the applicability of regulatory limitations prior to use.

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1.1 This provisional specification defines the Open Systems Interconnection (ISO7498 : 1984) Layer 2 data link layer for dedicated short-range communication (DSRC) equipment operating in half-duplex mode.1.1.1 This provisional specification defines the Data Link Layer irrespective of the physical medium to be used. However, it is expected that the standard will be used in accordance with a three layer stack as defined by Subcommittee E17.51 and IEEE P1455 and illustrated in . A critical implication of the use of the Data Link Layer standard with PS 111 is the assumption that the data rate will be 500 Kbps on both the uplink and downlink.1.1.2 This provisional specification specifies dedicated short range communications between fixed equipment at the roadside, called a beacon or Road Side Equipment (RSE) and Mobile Equipment in vehicles, called a Transponder or On-Board Equipment (OBE). This standard does not address vehicle-to-vehicle communication or communication between different instances of RSE.1.1.3 This provisional specification adheres to the general DSRC architecture in which the RSE controls the medium, allocating its use to OBEs within range of the RSE.1.1.4 This provisional specification supports a variety of RSE configurations. It supports configurations where one RSE communicates with one OBE, as well as configurations where one RSE can communicate with several OBEs. It does not define any specific configuration or layout of the communication zone.1.1.5 This provisional specification does not define to what extent different instances of RSE, operating in the vicinity of each other, need to be synchronised with each other.1.1.6 This provisional specification defines parameters to be used in negotiation procedures taking place between RSE and OBE.1.1.7 This provisional specification defines the following:Medium access control (MAC) procedures for the shared physical medium,Addressing rules and conventions,Data flow control procedures,Acknowledgement procedures,Error control procedures,Services provided to data link user(s), andFragmentation.1.1.8 There are two primary MAC modes, synchronous and asynchronous. Both modes support time-division multiple access half-duplex communications combined with a slotted aloha protocol for activation. The synchronous mode is characterized by a contiguous set of slots which is transmitted continuously and has fixed polling, data communications and activation phases. The asynchronous mode can vary the transmission of polling sequences, activation attempts or data communications.1.1.9 This provisional specification assumes that each RSE covers a limited part of the road (the communication zone) and that the OBE communicates with the RSE while passing through the communication zone.1.1.10 This provisional specification specifies the services required of the data link layer by the DSRC data link layer user, as viewed from the data link layer user, to allow a data link layer user entity to exchange packets with remote peer data link layer user entities. The services do not imply any particular implementation or any exposed interface.1.1.11 Not discussed in this provisional specification are signals that must be passed through the Data Link Layer from the Physical Layer to the Application Layer or vice versa in the OBE. These signals include indications of exceeding the wake-up threshold level (to control the OBE response in a small zone) and no carrier (to permit graceful shut down of the OBE if the OBE unexpectedly loses communications). It will be necessary to consider the implementation of these signals in OBE design.1.2 Overview1.2.1 All transmissions by either the RSE or OBE shall consist of a preamble and a frame. A preamble is an eight-bit sequence used for bit synchronization and is specified in Layer 1. A frame is a data link layer entity, which is the result of encapsulation of an application protocol data unit. The generic encapsulation process is shown in .1.2.2 An APDU is delivered from the application layer to the data link layer. If the APDU cannot be sent in a single transmission, then it is subdivided into multiple packets. Each packet is then converted into an LPDU by appending a byte count, fragmentation and logical link control and status field to the beginning of each packet. The frame is then formed by appending a link address field, and media access control field to the beginning and a error detection check field to the end of each LPDU. Each frame is then sent to the physical layer, which appends the preamble and then transmits the data.1.2.3 The frames can be transmitted in one of two modes: synchronous or asynchronous. In the synchronous mode, frames are transmitted in one of three types of slots: frame control message, message data or activation. The slots are combined to form a continuously repeated TDMA frame, as shown in . Each TDMA frame begins with a frame control message slot (FCMS). The FCMS only contains a frame control frame which is a broadcast message from the RSE indicating the number of slots, the type of each slot and the size of the slots that compose the rest of the TDMA frame. For example, in , the frame control frame defines a TDMA frame composed of three additional slots, two slots for data transmission and the other slot for activation. The message data slot (MDS) contains a data message frame transmitted over either the downlink to a specific OBE or uplink from a specific OBE. In addition, there is an acknowledgement transmitted immediately after the data message frame in the opposite direction. The activation slot (ACTS) consists of activation windows which are time periods when any OBE is allowed to transmit in contention with other OBEs in order to attempt to activate. It is not necessary to have an activation slot in a TDMA frame.1.2.4 Assuming link establishment requires the transmission of a beacon service table (BST) from the RSE and negotiation of link parameters using a vehicle service table (VST), provides an example of a full link negotiation followed by a read/write operation in synchronous mode. (Note that the full link negotiation can be shortened to reduce the number of TDMA frames needed to complete a transaction.) In TDMA Frame #1, the OBE receives a BST from the RSE and decides to activate. The activation is also transmitted in TDMA Frame #1. In TDMA Frame #2, the frame control frame designates a downlink message data slot to obtain the VST. After the OBE transmits the VST in TDMA Frame #2, the RSE commands the OBE to support a read in TDMA Frame #3. In TDMA Frame #4, the frame control frame designates an uplink message data slot to read the data. In TDMA Frame #5, the frame control frame designates a downlink message data slot to write data to the OBE. A corresponding acknowledgement is transmitted by the OBE.1.2.5 In the asynchronous mode, communications with an OBE is always initiated with a frame control frame which is regularly broadcast by the RSE. Immediately following the frame control frame are a series of activation windows. The timing and structure of the frame control frame and activation windows can be made common to both synchronous and asynchronous operations (to minimize the differences between the two modes). It is expected that the frame control frame and the activation windows will be transmitted (or time allocated) periodically so that the RSE can poll its read zone for OBEs. When an OBE successfully activates, the RSE discontinues transmissions of the frame control frame to establish private communications with the OBE. These communications can occur asynchronously, that is, without a TDMA frame dividing time into slots. In addition, the specific sequence of frames transmitted is dependent entirely on the application layer. Once the private communications is completed, the RSE would then continue to poll using the frame control frame and activation windows. Note that opportunities to transmit on the downlink and uplink in the asynchronous mode are defined by windows which provide constraints on the start and end times for any frame transmissions. An activation window is a special case of an uplink window.1.2.6 As above, assuming link establishment requires the transmission of a beacon service table (BST) from the RSE and negotiation of link parameters using a vehicle service table (VST), provides an example of a typical read/write operation in asynchronous operation.1.2.7 Like the synchronous mode, the OBE receives the BST from the RSE and attempts to activate. The activation frame is transmitted in activation windows that immediately follow the frame control frame. Once the activation is established, the RSE commands the OBE to transmit a VST and allocates an uplink window for the OBE to transmit the VST. After the VST is received, the RSE commands the OBE to support a read and allocates an uplink window for the OBE to transmit the read response. The OBE transmits the data. Then, the RSE writes data to the OBE and receives a reply that the write was successfully completed.Note 1Provisional Standards require only subcommittee consensus and are published for a limited time of two years. The provisional process was used because it is anticipated that the United States Department of Transportation will be referring to this provisional specification in their rule making.

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This specification covers stainless steel and heat-resisting chromium steel plate, and strips available in a wide variety of surface finishes. The steel shall conform to specified chemical composition requirements. Also, the material shall conform to the specified mechanical property and mechanical test requirements.1.1 This specification covers stainless and heat-resisting chromium steel plate, sheet, and strip available in a wide variety of surface finishes. 1.2 The values stated in inch-pound units are to be regarded as the standard. Note 1—Grades that were previously covered in both Specifications A 176 and A 240/A 240M have been removed from this specification and may now be supplied and purchased in compliance with Specification A 240/A 240M. The chemical and mechanical property requirements of these grades were identical in Specifications A 176 and A 240/A 240M at the time of removal from Specification A 176.

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The significance of these tests is mainly in their ability to differentiate, in a comparative sense, between different degrees of ozone resistance under the limited and specified conditions of the accelerated tests. These test methods may not give results correlating exactly with outdoor exposure tests or service performance since the correlation of accelerated ozone tests with such performance is highly dependent upon the specific conditions of both the accelerated ozone and outdoor exposures. Conditions that influence the accelerated tests are ozone partial pressure, air flow, temperature, stress-relaxation, and the bloom of additives. Outdoor or service performance is influenced by such weather conditions as rainfall, ambient temperature, sun light, and the strain cycles imposed.1.1 These test methods are used to estimate the cracking resistance of vulcanized rubber exposed under dynamic strain conditions to a chamber atmosphere containing ozone at a fixed partial pressure. The effect of sun or ultraviolet light is excluded. 1.2 These test methods are not applicable to materials ordinarily classed as hard rubber, but are adaptable to molded or extruded soft rubber. 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.

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This test method is used by athletic footwear manufacturers both as a tool for development of midsole material systems and as a test of the general characteristics of the athletic footwear product (see 1.4-1.6.2 and Notes 1-6). Careful adherence to the requirements and recommendations of this test method shall provide results which can be compared between different laboratory sources.Dynamic data obtained by these procedures are indicative of the shock attenuating properties (see 1.5) of the material systems under the specific conditions selected.This test method is designed to provide force versus displacement response of materials systems for athletic footwear under essentially uniaxial compression conditions at impact rates, which are similar to that for heel strike in normal running movements.2 ,3 That is, peak forces of up to 2 kN (450 lb) in times of 10 to 20 ms.The peak or maximum values of force, pressure, displacement, and strain are dependent on the maximum energy applied to the specimen. These values are normalized to provide comparative results for a reference maximum energy applied to the specimen of 5 J.Shock attenuating characteristics are strongly dependent on specimen thickness and prior history of force application. Therefore, results should be compared only for specimens of essentially the same thickness and prior impact conditioning (see Notes 3-6). There are no currently acceptable techniques for normalizing results for specimen thickness variations.Shock attenuating values (see 1.5) determined by this test method, for materials systems of athletic footwear, may not correlate with the similar values experienced by a runners heel or foot.1.1 This test method covers the measurement of certain shock attenuating characteristics, rapid rate force-displacement relationships, of materials systems employed in the midsole of athletic footwear intended for use in normal running movements. This test method covers three different procedures for performance of the rapid rate force application: Procedure A for falling weight impact machines, Procedure B for compression force controlled machines, and Procedure C for compression displacement controlled machines.1.2 The material system response for rapid rate force application may be different for each of the three procedures of this test method.1.3 This test method is empirically based on the use of an 8.5-kg mass dropped from 50 mm (1.97 in.) to generate peak compressive forces which are comparable to that experienced by a midsole in heel strike tests for normal running movement., This requires the specimen to be rigidly supported and the energy to be delivered through a 45-mm (1.8-in.) diameter flat tup.1.4 This test method imposes an impulse to generate a rapid rate compressive force-displacement hysteresis cycle and evaluates shock attenuating characteristics of the specimen. The maximum energy applied to the specimen occurs at peak displacement and must be within 10 % of a reference value that is used to normalize the data for comparative purposes.

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