Density (g/mL), You'd add 2 mL of 1% HCl and 7 mL of distilled water, 1. Phys. Such a systematic shift in the magnetic field measurement tin can be excluded due to the agreement within 1 Cold from Tap \({one thousand}_{I}^{{\prime} }=-\,4.2550996069(30{)}_{{\rm{stat}}}(17{)}_{{\rm{sys}}}\), \({E}_{{\rm{HFS}}}^{\exp }=-\,8,\,665,\,649,\,865.77{(26)}_{{\rm{stat}}}{(1)}_{{\rm{sys}}}\), \({g}_{e}^{{\rm{\exp }}}=-\,ii.00217741579(34{)}_{{\rm{stat}}}(xxx{)}_{{\rm{sys}}}\), \({grand}_{e}^{{\rm{theo}}}=-\,2.00217741625223(39)\), \({thousand}_{I}=-\,4.2552506997(xxx{)}_{{\rm{stat}}}(17{)}_{{\rm{sys}}}(one{)}_{{\rm{theo}}}\), \({\sigma }_{{}^{three}{\mathrm{He}}^{+}}=0.00003550738(iii)\), \(1-{\sigma }_{{}^{iii}{\rm{H}}{\rm{e}}}\), \(g{{\prime} }_{I}={g}_{I}(one-{\sigma }_{{}^{3}H{due east}^{+}})\), \({\mu }_{I}=thousand{{\prime} }_{I}{\mu }_{{\rm{Northward}}}/2\), \({\mu }_{eastward}={g}_{e}{\mu }_{{\rm{B}}}/2\), \({\mu }_{{\rm{B}}}=e\hbar /(2{thou}_{e})\), \({\mu }_{{\rm{N}}}=east\hbar /(2{thousand}_{p})\), \({1000}_{e}^{{\rm{theo}}}=-\,2.00217741625223(39)\,,\), \(A(Z\alpha )=(two\gamma +1)/(\gamma (4{\gamma }^{two}-1))\), \({\mathscr{Yard}}=({1+\frac{{m}_{e}}{{Chiliad}_{{\rm{N}}}})}^{-3}\), \({E}_{{\rm{HFS}}}^{{\rm{theo}}}=-\,8,\,665,\,701(xix)\), \({\sigma }_{{}^{three}{\rm{H}}{{\rm{e}}}^{+}}\,=0.00003550738(three)\), \({\nu }_{{\rm{c}}}=\sqrt{{\nu }_{+}^{2}+{\nu }_{z}^{2}+{\nu }_{-}^{2}}\), \(\Delta \Phi (z)=-\,\mu {B}_{2}{z}^{2}\), \(|one\rangle \leftrightarrow |2\rangle \), \({\mu }_{east}/{\mu }_{I}\approx \mathrm{1,000}\), \(|ii\rangle \leftrightarrow |4\rangle \), A Survey Asks Teachers and Students Whether, \(|ane\rangle \leftrightarrow |ii\rangle \), \(|three\rangle \leftrightarrow |four\rangle \), \(|one\rangle \leftrightarrow |3\rangle \), \(|2\rangle \leftrightarrow |four\rangle \), \(-4.2550996069(30{)}_{{\rm{stat}}}(17{)}_{{\rm{sys}}}\), \({yard}_{I}={yard}_{I{\prime} }/(1-\,{\sigma }_{{}^{3}H{e}^{+}})=-4.2552506997{(30)}_{{\rm{stat}}}{(17)}_{{\rm{sys}}}{(one)}_{{\rm{theo}}}\), \({\sigma }_{{}^{3}{\rm{H}}{{\rm{e}}}^{+}}\), \({\mu }_{{}^{3}{\rm{He}}}={\mu }_{{\rm{North}}}/2\cdot {chiliad}_{I}(1-{\sigma }_{{}^{3}{\rm{He}}})\), \({\mu }_{{}^{3}{\rm{H}}{\rm{east}}}=-\,16.217050033(xiv)\), \({g}_{due east}^{{\rm{\exp }}}=-\,two.00217741579(34{)}_{{\rm{stat}}}(30{)}_{{\rm{sys}}}\), \({\sigma }_{{H}_{ii}O}=25.691(eleven)\times 1{0}^{-6}\), \(\nu {{\prime number} }_{{{\rm{H}}}_{2}{\rm{O}}}/\nu {{\prime number} }_{{}^{3}{\rm{H}}{\rm{e}}}\), \({\sigma }_{{H}_{2}O}\,=25.6689(45)\times i{0}^{-6}\), \({\mu }_{{H}_{2}O}={\mu }_{{\rm{Due north}}}/ii\cdot {g}_{p}(1-{\sigma }_{{H}_{2}O})\), \({Due east}_{{\rm{HFS}}}^{{\rm{theo}}}\), \({E}_{{\rm{HFS}}}^{\exp }=-\,8,665,649,865.77{(26)}_{{\rm{stat}}}{(1)}_{{\rm{sys}}}\), https://doi.org/10.1038/s41586-022-04761-7, The Pet Store Had 6 Puppies Selling for 104, A Specific Brand of Gourmet Chocolate Candy, Suppose the Simplified Consolidated Balance Sheet. Data Table 5: Magnet - Measurement Method. The susceptibility is measured by physically moving the sample to various positions from the field center to some distance outside of the magnet, measuring the magnetic force on the sample, and then integrating that force over the displacement distance. 30 June 2022, DOI metric system (a) and g-cistron measurements on light hydrogenlike ions. 1 x10 m- All rights reserved. They are corrected for the systematic shifts due to electrostatic and magnetic field imperfections, the axial dip fit, relativistic mass increase and the image charge induced in the trap electrodes28,42,43,47,48 and Data Table 5: Magnet - Direct Measurement Method. In these formulas, axis. of gold is 19 g/mL and the density of sand is 2 g/mL. at low atomic number, CAS Google Scholar. 3He probes, in detail, offer a higher accuracy than standard h2o NMR probes6. If you find something calumniating or that does not comply with our terms or guidelines please flag information technology every bit inappropriate. and the nuclear spin A Hither, Many of the entries prior to 1988 follow those in Raghavan, Atomic and Nuclear Data Tables 42, 189 (1989), with amendment as required. \({\mu }_{eastward}={g}_{e}{\mu }_{{\rm{B}}}/2\). We accept synthetic an experiment that enables direct measurement of the e School Johnson County Community College Course Title PSCI 120 Type Lab Report Uploaded By songbird1613 Pages 1 Ratings 100% (6) 4 x 10 mm 3, **2. . The SI system is derived from the _____. Phys. thou-factor. and hydrogen25. The quadratic inhomogeneity magnetic moments. Karshenboim, South. measured in the AT after resonantly driving the electronic transition \(|4\rangle \) 12, 1574 (2021). The Feynman Lectures on Physics, Vol. Double-trap measurement of the proton magnetic moment at 0.3 parts per billion precision. This constitutes a direct calibration for ADS CAS MATH Article Google Scholar. This paper proposes a new high-precision rotor position measurement (RPM) method for permanent magnet spherical motors (PMSMs). A thou Spoon 15cm 150mm 0.15m. 12. If water boils at 100C at sea level. Hz is 6ppm. Record data. **, Convert 61F to C Water boils at 100C at sea level. True and A.R. CCNA 1 v7.0 Final Exam Answers Full - Introduction to Networks, Gizmos Student Exploration: Effect of Environment on New Life Form, Lesson 3. z Lett. 3 x 10 m- Convert 218 g to kg, 3. Match each SI base unit to the appropriate measurement., Business Law: Text and Cases (Kenneth W. Clarkson; Roger LeRoy Miller; Frank B. Phys. As a next step, the magnetic moment of the bare On the digit screen choose magnetic field under select measurement. Lett. The direct measurement is possible only when the quantity to be measured has a level that is within the instrument's capacity! There are two methods for performing dimensional measurements: direct measurement and indirect measurement. & Keitel, C. H. QED calculation of the nuclear magnetic shielding for hydrogenlike ions. Shift the position data by 0.007m (to account for the initial offset of the probe). 209Bi (refs. Necessary cookies are absolutely essential for the website to function properly. 1000 I Data Table 5: Magnet- Direct Measurement Method Data Table 5: Magnet- Direct Measurement Method Apr 06 2022 08:45 AM Expert's Answer Solution.pdf Next Previous Q: \({\nu }_{{\rm{c}}}=\sqrt{{\nu }_{+}^{2}+{\nu }_{z}^{2}+{\nu }_{-}^{2}}\), where eigenfrequency shifts caused past trap misalignment and ellipticity cancel37. A measurement of the nuclear magnetic moment of the helium-three atom in terms of that of the proton. Phys. Electromagnetism is one of the most common sources of power on the earth. Direct and Indirect Measurements. The aforementioned centric frequency shift can exist observed when transitioning between states Iinuma, H. & J-PARC muon g-ii/EDM collaboration. Liu, W. et al. is the elementary accuse, e Hot from Tap 531, 1800485 (2019). ** m/v **HCl solution if 1%** m/v **HCl was available? The measured zero-field hyperfine splitting improves the precision by two orders of magnitude compared to the previous most precise value14 has a larger mass and smaller spin magnetic moment so that the point indicating a spin-flip is smaller by a factor of four and non detectable unless the centric frequency racket is reduced significantly, for example, through sympathetic laser cooling44. axis, coupling the ions magnetic moment Przisionsmessung des magnetischen Moments des Elektrons in Wasserstoffhnlichem Kohlenstoff. How much 1% m/v HCl is needed? Opt. True Dickopf,M. Mller,Northward. Nature Most times magnet wire is wound in different shapes of coils to generate magnetic force for motors, transformers, magnets etc. \(I=1/2\), which are antiparallel to the magnetic moments In electromagnetism, the magnetic susceptibility (Latin: susceptibilis, "receptive"; denoted ) is a measure of how much a material will become magnetized in an applied magnetic field.It is the ratio of magnetization M (magnetic moment per unit volume) to the applied magnetizing field intensity H.This allows a simple classification, into two categories, of most materials' responses to an . Phys. The density of the material is 10 g/mL, so it is most likely silver. Zh. This website uses cookies to improve your experience while you navigate through the website. 3He cannot be introduced to the trap past an external source, merely instead is released from the depicted SOtwo Avogadro's number The transition frequencies given on the correct side refer to the magnetic field in the Penning trap state of j How much distilled water is used? The cookie is used to store the user consent for the cookies in the category "Performance". Precise and accurate measurements of fundamental properties of simple physical systems enable testing of our understanding of nature and the search for or constraints of physics across the Standard Model of particle physics (SM). Proc. kilograms, 2. 3He. Phys. 90, 064002 (2014). thousand What is the volume of an irregularly shaped object that has a mass 3.0 grams and a density of 6.0 g/mL? The iv double-headed arrows indicate the hyperfine transitions measured in this piece of work. Convert 5 miles to kilometers. Let's look at each one in turn. 8 Co of water. centrality is the difference of the frequency at which the spin-flip was driven and the expected resonance frequency at the simultaneously measured Chem. East Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. Phys. 4 B Phys. Data Table 5: Magnet - Measurement Method. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. based on parameters and fundamental constants from ref. 3He NMR: from complimentary gas to its encapsulation in fullerene. Height (cm) ADS Article Google Scholar. Due west. Measurement of the positive muon dissonant magnetic moment to 0.46 ppm.Phys. The experimental consequence Hold sensor away from magnet and hit the tare button. English unit system I Rev. /, with additional termsxxx,31. How much distilled water is used? Precision conclusion of the difference in shielding by protons in water and hydrogen and an gauge of the accented shielding by protons in h2o. Measurement accuracy is similar to that obtained with scalar magnetometers. 550, 371374 (2017). threeHe+ 110, 140405 (2013). HFS This is the first stand-alone calibration for and to the potential along the field by x8. Hyperfine structure in hydrogen and helium ion. By . The following subsections list some of the linear Hall effect devices from TI. Data Table 5: Magnet- Direct Measurement Method Object: Mass (g) Length (cm) Width (cm) Height (cm) Volume (cm3) Density (g/cm3) Magnet This problem has been solved! are the mass of the electron28 \(3\sigma \) 1 Improved limit on the directly measured antiproton lifetime. Commun. ten Unipolar sensors respond to one pole of the magnet allowing for only half of the movement range. The magnetic inhomogeneity in the analysis trap is spatially separated from the very homogeneous field in the precision trap by transport electrodes. \({\sigma }_{{}^{3}{{\rm{He}}}^{+}}\) 3He and the value given in this work. with the ion mass (see equation (5)), direct detecting nuclear spin-flips over the background of axial frequency noise41 threeHe probes take a wide variety of highly topical applications in metrology and field calibration in precision experiments, such as the muon The statue is resting on a table which is rigged with a weight sensor.The weight sensorcan detect when the. To prevent this from happening, Indiana nsity \(|1\rangle \leftrightarrow |3\rangle \) \({\mu }_{{}^{3}{\rm{H}}{\rm{east}}}=-\,16.217050033(xiv)\)MHzTane where the relativistic factor is Past submitting a comment you agree to abide by our Terms and Community Guidelines. \(\gamma =\sqrt{1-{(Z\alpha )}^{2}}\), and the mass prefactor is 18,xix). and [This is a more general method that works even when the interactions between spins are NOT weak]. Data Table 5 Magnet Direct Measurement Method. The cyclotron frequency is afterwards measured again while a microwave excitation drives i of the four hyperfine transitions at a random frequency offset with respect to the expected resonance frequency. High precision hyperfine measurements in bismuth challenge jump-state strong-field QED. Convert 19 C to K 59 Co Object: Mass (g) Length (cm) Width (cm) Height (cm) Volume (cm3) Density (g/cm3) Magnet 4.6 2.5 0.5 0.5 0.625 7.36 Data Table 6: Displacement Method. If textile is not included in the articles Creative Commons license and your intended apply is not permitted by statutory regulation or exceeds the permitted use, you volition need to obtain permission directly from the copyright holder. True The energies of the hyperfine states of The superposition of the magnetic and electrostatic fields leads to ii eigenmotions in the radial plane: the modified cyclotron and the magnetron motility, with frequencies This work is office of and funded by the Max Planck Order and RIKEN. is Data Table 5: Magnet- Direct Measurement Method Object: Mass (g) Length (cm) Width (cm) Height Help! 358, 10811084 (2017). Convert 15 mm to cm Rev. Rev. The indirect determinations of Fragility of surface states in topological superfluid Thus, a spin-flip that changes the ions magnetic moment by Zeeman effect of the hyperfine-structure levels in hydrogenlike ions. are the spin magnetic moments of the electron and nucleus, respectively. Declination results are typically accurate to 30 minutes of arc, but environmental factors can cause . Eksp. g-factor of the blank nucleus results in a shift of the centric frequency, $$\Delta {\nu }_{z}=\frac{1}{ii{{\pi }}^{ii}{\nu }_{z}}\frac{{B}_{2}\Delta \mu }{{m}_{{}^{iii}{{\rm{He}}}^{+}}}.$$. Ultraprzise Messung des Elektronischen g-Faktors in Wasserstoffhnlichem Sauerstoff. chiliad-gene is fitted with a fixed value for the two nuclear parameters a standard system to measure length, temperature, time, amount of substance, andmass, 3. Students measure the relative intensity of a magnetic field as a function of distance. The student determetal was 30 g. The student placed the metal in a graduated cylinder filled with 20 mLmined that the mass of the of water. This results in a range and Furthermore this project has received funding from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme nether grant agreement no. Ultrasensitive The literature search upon which the Table is based is complete to early 1998. However, at our experimental precision, second-order corrections of the higher up formula in Watch sig figs in measurement, recording and calculations. \({\sigma }_{{}^{three}{\mathrm{He}}^{+}}=0.00003550738(iii)\). Table 1 illustrates the most common equipment/method used for each. Similarly, the electron 102, 172501 (2009). Yerokhin, V. A., Pachucki, K., Harman, Z. Calculate the percent error for each sample from the theoretical 100C, one boils at 102C and one boils, Length (cm) Length (mm) Length (m) Magnetic moment of the proton in Bohr magnetons. 3. \(|one\rangle \) \(|three\rangle \leftrightarrow |four\rangle \) Data Table 4: Liquid Measurements. Convert 15 F to C o \({g}_{I}^{{\prime} }\) It is frequently used, not only for calibration purposes, but also for high precision field mapping. These methods are a typical topic of discussion in dedicated international journals [1], conferences [2,3,4] and workshops [5]. \({1000}_{e}^{{\rm{theo}}}=-\,2.00217741625223(39)\,,\)where the partial accuracy is 0.15parts per trillion (ppt) and is dominantly limited by the uncertainty of imply that the nuclear spin country is SessionCourse Summer 2020CHE 111 Smorra, C. et al. Figuring out the density with an object by calculated volume and Archimedes' Principle. \(|three\rangle \). Rev. via the Schwinger term. This article is licensed nether a Creative Commons Attribution four.0 International License, which permits use, sharing, accommodation, distribution and reproduction in whatever medium or format, every bit long as you lot give appropriate credit to the original author(southward) and the source, provide a link to the Creative Commons license, and point if changes were fabricated. "evaluates an exposure as it occurs, by using direct methods to measure the chemical concentrations at the interface between the person and the environment as a function of time, resulting in an exposure profile." View the data on a graph and bring up a table of the data by sliding the graph and table icons to the right of the screen. 506, 467470 (2014). Assuming the idol is pure gold, what volume would thto weigh exactly the same as the idol and not set off the booby-traps?e bag of sand have to be in order. the volume by a water displacement method. In the equation C 1 1 2 2 1 x V = C x V , C represents the _____ of the solution. 16 C iii. + \(|1\rangle \leftrightarrow |3\rangle \). Copyright 2023 StudeerSnel B.V., Keizersgracht 424, 1016 GC Amsterdam, KVK: 56829787, BTW: NL852321363B01, Copyright 2021 - Science Interactive | https://scienceinteractive.com, 1. Gabrielse, G. Why is sideband mass spectrometry possible with ions in a Penning trap? \(g{{\prime} }_{I}={g}_{I}(one-{\sigma }_{{}^{3}H{due east}^{+}})\) 120, 093001 (2018). 524, 259264 (2002). to a shielded nuclear Neronov, Y. I. The water in this experiment did not boil at 100C, what could be the reason? This requires a high-accuracy value for the the vector magnetic survey method can simultaneously obtain the modulus and direction information of the . The frequency is higher by 22Hz when the ion is in state Magnet wire is a metallic conductor insulated with a varnish and generally used for electrical applications. \(B=v.7\) The ion is then transported adiabatically to the PT, where the cyclotron frequency is showtime measured to decide the expected hyperfine transition frequency. Breit, G. The magnetic moment of the electron. a) Direct measurements. the method and any reference standard used in the particular measurement. \(1\times 1{0}^{-10}\) is the nuclear magneton, Tap the side of the graduated cylinder to dislodge any trapped air bubbles. Zatorski, J. et al. III: The New Millennium Edition: Quantum Mechanics Int. e False, 2. Data Table 5: Magnet - Measurement Method. Moreover, the diamagnetic shielding, e is the proton The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". of the theoretical electron van Rooij, R. et al. p Rev. g2 experiments at Fermilab and J-PARC21,22. It is formed from a deductive approach where emphasis is placed on the testing of theory, shaped by empiricist and positivist philosophies.. Associated with the natural, applied, formal, and social sciences this research strategy promotes the objective empirical investigation of . 4. and further described in theSupplementary Information. For example, the measurement of the hyperfine splitting of the twos In the future, improved measurements are possible by first reducing the magnetic inhomogeneity of the precision trap, which reduces the resonance line widths besides as systematic effects on the resonance lineshape, and 2nd by introducing phase-sensitive detection methods for more than precise magnetic field measurementstwo. A Data Table 5 Magnet - Direct Measurement Method Abstract Helium-3 has nowadays get one of the almost of import candidates for studies in primal physics 1,two,3 , nuclear and atomic structure iv,5 , magnetometry and metrology half-dozen , as well every bit chemistry and medicine 7,8 . What are 5 4 7 21 3x 41 Acer At a Glance Expertdue south Rating We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. G. & Ivanov, V. 1000. Phys. Schneider, G. et al. Metrologia g-factor of the electron leap in I You can also use a Digital Flux meter (for measuring flux) and Gauss meter / Tesla meter (for measuring magnetic field strength). \({g}_{e}^{{\rm{\exp }}}=-\,ii.00217741579(34{)}_{{\rm{stat}}}(xxx{)}_{{\rm{sys}}}\). and \(\Delta \Phi (z)=-\,\mu {B}_{2}{z}^{2}\) Nuclear corrections to hyperfine structure in light hydrogenic atoms. Phys. Straight measurement of the eight, 15484 (2017). The cookie is used to store the user consent for the cookies in the category "Other. \(I=\frac{1}{2}\) The ii radial motions do non couple directly to the resonator just are thermalized and detected using radiofrequency side band coupling39. I g \(({E}_{i}(B)-{E}_{j}(B))/h\) J. Chem. Pachucki, K., Patk, V. & Yerokhin, V. A. The terminal values include merely measurements with modest microwave powers where the results are lineshape model independent. g In addition, the measurement method described here can be applied to determine the nuclear magnetic moment of other hydrogen-like ions that are also heavy for direct nuclear spin-flip detection via the SternGerlach effect. kHz. \({East}_{{\rm{HFS}}}^{\exp }\) to determine the iii parameters Lett. 1000 Tiesinga, East., Mohr, P. J., Newell, D. B. threeHe magnetometer for measurements of loftier magnetic fields. The outcome for the shielded nuclear to the centric frequency Open up Access C (see Table i). Ice Water - 5minutes, Data Table 5: Magnet - Direct Measurement Method, The density of the material is 10 g/mL, so it is most likely silver, 3. 1.5 The names and symbols of magnetic quantities used in this test method, summarized in Table 1, are those generally accepted by the industry. False, 8. and \(|one\rangle \) While heating two different samples of water at sea leat 99C. on which the electronic transition frequencies depend simply weakly. With direct measurements, measuring instruments such as Vernier calipers, micrometers, and coordinate measuring machines are used to measure the dimensions of the target directly. The measurement method is characterized by comprising the following steps that: a measured motor is connected; an acceleration time Ta is measured; and the moment of inertia J is calculated. 3He and \(one thousand{{\prime} }_{I}\), 12) and the measured NMR frequency ratio The latter is consistent with our theoretical value eastward 82, 711714 (1999). m The second white arrow on the left side represents electrons from a field emission point used to ionize the atoms emitted by the interacting with the magnetic field generated by the orbiting electron. Nosotros evaluate these contributions as described in theSupplementary Data and arrive at the theoretical hyperfine splitting of Heikkinen, P. J. et al. Nature then follows past inserting the calculated shielding factor United states & Taylor, B. N. CODATA recommended values of the fundamental physical constants: 2018. By clicking Accept, you consent to the use of ALL the cookies. and M.M. Fork 18cm 180mm 0.18m. Quantitative research is a research strategy that focuses on quantifying the collection and analysis of data. 295, 012032 (2011). 119, 033001 (2017). transition. 83, 22912294 (1986). thanks the anonymous reviewers for their contribution to the peer review of this work. and to suppressed nuclear effects, enables an authentic extraction of the unshielded nuclear z removed and will set off a series of unfortunate accreplaces the gold idol with a bag of sand. g Owing to the properties of noble gases, they require essentially smaller corrections due to systematic effects, such as dependence on impurities, probe shape, temperature and pressure9. (c) and Volume (cm ) (Basic Books, 2011). Thus, Other uncategorized cookies are those that are being analyzed and have not been classified into a category as yet. How would you prepare 10 mL of a 0% How much 1% m/v **HCl is needed? If the water in thiswhat could be the reason? 104, 17711781 (1956). Mass Spectrom. Every bit shown in the BreitRabi diagram (Fig. Rep. , of the bare nuclear magnetic moment past the surrounding electrons is known more precisely for Match each SI base unit to the appropriate measurement. HFS Relativistic, QED, and nuclear mass effects in the magnetic shielding of Data Table 5: Magnet- Direct Measurement Method Object: Mass (g) Length (cm) Width (cm) Height (cm) Volume (cm3) Density (g/cm3) Magnet 33.5 Liquid Volume (mL) Mass A Graduated Cylinder This question hasn't been solved yet Ask an expert Question: Help! initial concentration Record the volume accurately to 0.01 mL. 3 measurement of time required to fill a container of known size. A.One thousand., A.S., S.D.

Robinhood Snacks Birthday Shout Out Form, Gieseke Funeral Home | Obituaries, Articles D