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1.
P. Bloembergen M. Battuello F. Girard G. Machin L. Wright 《International Journal of Thermophysics》2016,37(4):44
This paper considers the influence of the thermal inertia of the furnace on the shape of the melting curve of the eutectic Co–C. To this end, melting experiments have been performed in a uniform three-zone furnace, with an inherent substantial thermal inertia. The thermal inertia has been quantified by measuring the step-response of the furnace with the sample in its solid state, just below its melting temperature. From the analysis of the effect of the thermal inertia of the furnace, it turned out that during melting the temperature distribution within the furnace, surrounding the crucible, is bound to be in a non-stationary state. This provided the key to properly finalizing the correction to be applied. The shape of the corrected curve differs considerably from that of the curve, as measured, in that the former shows a flatter melting plateau, and a larger curvature on the way down to the solidus point. As regards the liquidus temperature \(T_{\mathrm{liq}}\)—of major interest in the characterization of the transition temperature of high-temperature fixed points—it is demonstrated that the thermal inertia of the furnace shows a kind of self-compensating mechanism. But the effects of the thermal inertia of the furnace on the parameters defining the Scheil fit, involved in the correction procedure, were considerable. 相似文献
2.
On the basis of a survey of works, we demonstrate the priority of the Lviv school of mechanics in the field of creation and development of the deformation theory of limiting equilibrium of bodies with cracks known as the
k
-model. The theory is based on the criterion of crack opening displacement proposed by Leonov and Panasyuk and on the procedure of evaluation of this quantity by modeling the inelastic zones in front of the crack by cuts the edges of which are loaded by certain stresses 0 whose physical meaning is determined by the properties of the material. This method (known as the model of plastic strips) is also used for the determination of the development of plastic zones at the crack tip for various configurations of plates and loads and also in twisted bodies. The results of numerical calculations agree with the experimental data. 相似文献
3.
On the 23 March 2018, the most recent developments of the environmental impact assessment (EIA) law were examined by experts in Helsinki. The main theme of the conference was the comparison of the implementation experiences of various countries concerning the reformed EU EIA Directive. The European EIA debate was reflected against experiences in Canada. This paper examines the key points of the conference presentations and the lessons of the event. 相似文献
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Glasses in the system xGd2O3·(100 − x)[TeO2·GeO2] with 0 ≤ x ≤ 50 mol% have been prepared from melt quenching method. In this paper, we investigated changes of the coordination numbers
of germanium, tellurium, and gadolinium ions by investigations of FTIR, EPR, and UV–VIS spectroscopy. By analyzing the structural
changes resulted from the IR spectra we found that the bending modes of [GeO4] structural units and the deformed modes of the Te–O–Te linkages produce intercalation of the [GdO
n
] entities in the germanate–tellurate chain network and densification of the glasses by increasing the number of [GeO6] structural units. EPR spectra of the studied samples reveal that the gadolinium ions play a role of network former. The
UV–VIS spectra show broad UV absorption bands located in the 250–350 nm region. Their intensity increase with the increasing
of Gd2O3 content showing that these stronger transitions can be due to the presence of the O=Ge bonds (n–π* excitations) of [GeO5] structural units. The [GeO5] structural units are more stable thermodynamically than their analogues and the [GeO6] structural units produce the improvement of the amorphous character of these glasses. 相似文献
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《中国标准化(英文版)》2005,(5)
Testing C enter,ShanghaiR esearch Institute ofM aterials(SR IM T C),w hich isalso M aterials Testing C enter forM achinery Industry,w as founded on D ec.1994,based on the relevanttesting departm ents ofShanghaiR esearch Institute ofM ate-rials(SR IM).T he centerhas carried forw ard the experience and achievem ents onm aterials testing technology thatSR IM gained overthe past60years and achievedan increasingly good creditin the sam e profession hom e and abroad.In D ec.1996,SR IM … 相似文献
9.
《Materials Letters》2001,47(4-5):225-230
In the present investigation, different alloy compositions close to the ternary composition values, where the icosahedral phase in AlFeCu is obtained, have been studied. The specimens were obtained using a rapid solidification technique with subsequent thermal treatments of 600°C, 700°C, 800°C and 900°C. The obtained specimens were characterized with X-ray diffraction patterns (XRD) and transmission electron microscopy (TEM). The experimental results show different transformations of the icosahedral phase to crystalline phases between 800°C and 700°C .The cubic β-phase is a solid solution which regulates the formation and decomposition of the ψ-Al6Cu2Fe phase to different crystalline phases such as the tetragonal (Al7Cu2Fe) and monoclinic (Al13Fe4) phases. 相似文献
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《工业工程与管理》1998,(1)
Oursocietyisinanerafullofchangesandref0rms.Insuchanera,enterprisesneedreform,andtheyshouldseizetheopportunitiesinachangingenvironmenttoseekdevelopmentwithprospectsforfuturegrowth-Atpresent,theChineseenterprisesarejustsituatedinsuchanenvi-ronmenttoseektheirsurvivalanddevel0pment.Theyarefacingboth0pportunitiesandchal-lenges.Theestablishmentofmodernenterprisesystemshallprovidethemwithagreatopportu-nitytoadvancetotheoutsideworldandtoachievesuccess.Thereformofanenterprisecannotbeseparatedfromthepr… 相似文献
12.
《工业工程与管理》1997,(2)
Weareinaneraofgreatchangeandreform.ThepoIiticaIandeconomicchangeshaveraisedfresherandhigherdemandsonthemanufacturingindustry.ManyoftheoIdmarketstructureshavebeenbrokendown,andmoreandmoreenterpriseshavecometoreaIizethattheirproductionandorganizationsimpIymustundergoreformingandrestructuring.Toachieveandmaintaincompetitiveability,anenterpriseshouIdnotonIyneedIeanandfIexibleproductionsystemsbutaIsopossesspersonneIwhoarebothofstronginitiativeandwelI-trained.Thisisthekeytosuccessofanyenter-pri… 相似文献
13.
One of the main elements of the theory of constraints is its Drum–Buffer–Rope (DBR) scheduling (or release) mechanism that controls the release of jobs to the system. Jobs are not released directly to the shop floor – they are withheld in a backlog and released in accordance with the output rate of the bottleneck (i.e. the drum). The sequence in which jobs are considered for release from the backlog is determined by the schedule of the drum, which also determines in which order jobs are processed or dispatched on the shop floor. In the DBR literature, the focus is on the urgency of jobs and the same procedure is used both for backlog sequencing and dispatching. In this study, we explore the potential of using different combinations of rules for sequencing and dispatching to improve DBR performance. Based on controlled simulation experiments in a pure and general flow shop we demonstrate that, although the original procedure works well in a pure flow shop, it becomes dysfunctional in a general flow shop where job routings vary. Performance can be significantly enhanced by switching from a focus on urgency to a focus on the shortest bottleneck processing time during periods of high load. 相似文献
14.
《工业工程与管理》1997,(6)
IndustrialEngineeringandManagementisalreadyoneyearoldsincethepublicationofitsfirstissuelastDecember.Overthepastyear,ourreadershavewitnessed,togetherwithus,thevariouschangesofthisjournal.Atthemomentofitsfirstan-niversary,theurgentandimportanttaskforusistoreviewtheexperiencesandlessonswehavegainedinourworkandoutlinetheprospectiveorientationofdevelopmentforthefurtherimprovementofthejournalinthefollowingyear.AnnafterthepublicationofthefirstissueofIE&MinDecember,1996,wereceivedalargenumberoflett… 相似文献
15.
《工业工程与管理》1998,(2)
ThedevelopmentofindustrialengineeringhasundergoneacourseofoveracenturyinAmer-icasinceFrederickW.Taylorstartedhisobservationandanalysisofworkers'manualoperation.Todaywiththedevelopmentofinformationtechnology,computertechnologyhasbeenintroducedintoindustrialengineering,whichhasthusbeenfurtherdividedintoClassicalIEandModernIE.Industrialengineersareplayingagreatroletoday.Then,whatisanindustrialengineer?Andwhattypesofenterprisesuseindustrialengi-neers?Thisisoneofthequestionswhichmanypeoplearep… 相似文献
16.
An analysis of the Senarmont method is performed using Müller marices and Stokes, vectors. It is proved that the traditional
undrstanding of the Senarmont method is applicable in the case of phase differences not exceeding one-half wave. For measurements
of phase differences in the range 0–2π, a preliminary identification of the rapid and slow axes of the phase plate is required.
A method is presented by means of which it is possible to distinguish the axes on the basis of the direction of the rotation
of the resultant plane oscillations in the case of continuous variation of the phase differences.
Translated from Izmeritel'naya Tekhnika, No. 11, pp. 22–25, November, 1999. 相似文献
17.
A. I. Igolkin 《Materials Science》1995,30(1):72-74
Some common features of the transgranular embrittlement of -titanium alloys in chloride solutions, hot salts, liquid metals, and air are established. These types of brittle fracture are typical symptoms of trans-granular embrittlement along the basal (near-basal) cleavage planes of metals (alloys) with hcp crystal lattices with various values of the ratioc/a. In this connection, the role of alloying elements and the mechanism of corrosion cracking of -titanium alloys in chloride solutions are reconsidered.Central Scientific Research Institute of Structural Materials Prometheus, St. Petersburg. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 30, No. 1, pp. 75–77, January–February, 1994. 相似文献
18.
《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1988,270(1):146-148
A Monte Carlo simulation for the study of the influence of the thickness of the radioactive source in β-ray spectroscopy is presented in this paper. We make use of the Bethe-Bloch formula for ionization loss and Rutherford scattering cross section to trace the tracks of the β particles from a randomly sampled point source of given energy, which has been implanted in an aluminum coating with copper backing. We have studied seven groups of β rays with momenta from 119.14262 to 139.12328 keV/c. There are the peak shift, the broadening of the line width and the low energy tail. Their momentum dependences have been found. The program can be applied to similar cases with minor modification. 相似文献
19.
Nez F Antognini A Amaro FD Biraben F Cardoso JM Covita D Dax A Dhawan S Fernandes L Giesen A Graf T Hänsch TW Indelicato P Julien L Kao CY Knowles PE Le Bigot E Liu YW Lopes JA Ludhova L Monteiro CM Mulhauser F Nebel T Rabinowitz P dos Santos JM Schaller L Schuhmann K Schwob C Taqqu D Veloso JF Kottmann F Pohl R 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2011,369(1953):4064-4077
It is now recognized that the International System of Units (SI units) will be redefined in terms of fundamental constants, even if the date when this will occur is still under debate. Actually, the best estimate of fundamental constant values is given by a least-squares adjustment, carried out under the auspices of the Committee on Data for Science and Technology (CODATA) Task Group on Fundamental Constants. This adjustment provides a significant measure of the correctness and overall consistency of the basic theories and experimental methods of physics using the values of the constants obtained from widely differing experiments. The physical theories that underlie this adjustment are assumed to be valid, such as quantum electrodynamics (QED). Testing QED, one of the most precise theories is the aim of many accurate experiments. The calculations and the corresponding experiments can be carried out either on a boundless system, such as the electron magnetic moment anomaly, or on a bound system, such as atomic hydrogen. The value of fundamental constants can be deduced from the comparison of theory and experiment. For example, using QED calculations, the value of the fine structure constant given by the CODATA is mainly inferred from the measurement of the electron magnetic moment anomaly carried out by Gabrielse's group. (Hanneke et al. 2008 Phys. Rev. Lett. 100, 120801) The value of the Rydberg constant is known from two-photon spectroscopy of hydrogen combined with accurate theoretical quantities. The Rydberg constant, determined by the comparison of theory and experiment using atomic hydrogen, is known with a relative uncertainty of 6.6×10(-12). It is one of the most accurate fundamental constants to date. A careful analysis shows that knowledge of the electrical size of the proton is nowadays a limitation in this comparison. The aim of muonic hydrogen spectroscopy was to obtain an accurate value of the proton charge radius. However, the value deduced from this experiment contradicts other less accurate determinations. This problem is known as the proton radius puzzle. This new determination of the proton radius may affect the value of the Rydberg constant . This constant is related to many fundamental constants; in particular, links the two possible ways proposed for the redefinition of the kilogram, the Avogadro constant N(A) and the Planck constant h. However, the current relative uncertainty on the experimental determinations of N(A) or h is three orders of magnitude larger than the 'possible' shift of the Rydberg constant, which may be shown by the new value of the size of the proton radius determined from muonic hydrogen. The proton radius puzzle will not interfere in the redefinition of the kilogram. After a short introduction to the properties of the proton, we will describe the muonic hydrogen experiment. There is intense theoretical activity as a result of our observation. A brief summary of possible theoretical explanations at the date of writing of the paper will be given. The contribution of the proton radius puzzle to the redefinition of SI-based units will then be examined. 相似文献
20.
Faulkner K 《Radiation protection dosimetry》2005,117(1-3):318-320
Justification of medical exposures is a fundamental principle of radiation protection. This principle applies to mammographic screening, both for the screened population and at an individual level. The benefit of mammographic screening may be considered to be the number of cancers detected or lives saved by breast screening. The risk is the hypothetical number of fatal cancers induced by the use of ionising radiation in screening mammography. Benefit can be deduced from the cancer detection rate in the NHS Breast Screening Programme. The number of additional lives saved by the intervention of a screening programme may be deduced from knowledge of the change in tumour size, stage and nodal status (and hence prognosis) in women with screening detected breast cancers compared with symptomatic women before screening. Calculations of benefit risk ratios to the UK population have been performed. It is concluded that breast screening is justified in radiation protection terms. 相似文献