192 research outputs found
Features of dynamic nuclear polarization in irradiated LiD target material
No full textKiselev Y, Doshita N, Goertz S, et al. Features of dynamic nuclear polarization in irradiated LiD target material. Presented at the 16th International Spin Physics Symposium (SPIN 2004), Trieste, Italy
On the large COMPASS polarized deuteron target
No full textBall J, Baum G, Doshita N, et al. On the large COMPASS polarized deuteron target. Czechoslovak Journal of Physics. 2006;56:F295-F305
The COMPASS polarized target in 2006 and 2007
No full textDoshita N, Ball J, Baum G, et al. The COMPASS polarized target in 2006 and 2007. In: AIP Conf.Proc. Vol 980. AIP; 2008: 307-311
Investigations of the Multimode Cavity for the Compass-Magnet
No full textKisselev Y, Doshita N, Heckmann J, et al. Investigations of the Multimode Cavity for the Compass-Magnet. In: T. Uesaka HS, AY, & KA,, ed. Polarized Sources and Targets. WORLD SCIENTIFIC; 2007: 63-66
Future Activities of the Compass Polarized Target
No full textDoshita N, Heckmann J, Hess C, et al. Future Activities of the Compass Polarized Target. In: T. Uesaka HS, AY, & KA,, ed. Polarized Sources and Targets. WORLD SCIENTIFIC; 2007: 50-53
The satisfiabilty problem for a class consisting of horn sentences and some non-horn sentences in proportional logic
No full textIn this paper, the satisfiability problem for a class of proportional sentences is considered. Here a sentence is a set of clauses. A clause is a set of literals. First, it is proposed that a class S0 of propositional sentences which properly includes the class of propositional Horn sentences. A sentence {C1,…, Cn} is in S0 if there are sets P1,…,Pn of positive literals such that (1) P1 ⊃ P2 ⊃ … ⊃ Pn, (2) PiCi for 1 ⩽ i ⩽ n, and (3) Ci − Pi is a Horn clause for 1 ⩽ i ⩽ n. Then it is proposed that a new inference rule, based on the resolution principle, by which (un)satisfiability for S0 in polynomial time can be decided
Performance of the COMPASS polarized target dilution refrigerator
No full textDoshita N, Ball J, Baum G, et al. Performance of the COMPASS polarized target dilution refrigerator. In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Nucl.Instrum.Meth. A. Vol 526. Elsevier Science BV; 2004: 138-143.The dynamic nuclear polarization (DNP) of (LiD)-Li-6 requires 1 mW/g or more microwave power in the beginning of the process. With the material of 350 g, this gives more than 350 mW in total for the COMPASS polarized target. A temperature around 300 mK or below is needed for an efficient polarization. These low temperatures can only be achieved with a dilution refrigerator designed to operate with a He-3 flow of 100 mmol/s. In order to keep the polarization in the frozen mode, temperatures of about 65 mK are used with typical magnetic relaxation times of more than 1400 h at 0.42 T and of more than 15 000 h at 2.5 T. Low lattice temperature is important in achieving high nuclear polarization. The base temperature is limited by the heat brought to the mixing chamber by the inlet 3 He and by radiation and conduction of heat. (C) 2004 Elsevier B.V. All rights reserved
The COMPASS polarized target
No full textDoshita N, Ball J, Baum G, et al. The COMPASS polarized target. In: Czechoslovak Journal of Physics. Czechoslovak Journal of Physics. Vol 55. Springer Science and Business Media LLC; 2005: A367-A374.The spin structure of the nucleons is investigated by studying spin dependent process of deep inelastic scattering of a polarized muon beam and a polarized nucleon target in the COMPASS experiment since 2001. In order to achieve high luminosities it is necessary to use a large solid polarized target. The target consists of two independent and oppositely longitudinal polarized cells. The cells are filled with irradiated (LiD)-Li-6 granulated material. One of the characteristics of the polarized target is the spin reversal by magnetic field rotation in order to cancel the systematic error. The polarized target apparatus consists of a large refrigerator providing a low temperature of below 100mK and a high cooling power with 200-300 mK, a superconducting magnet producing 2.5 T with good field homogeneity, two high power of a few watts microwave systems producing 70 GHz for Dynamic Nuclear Polarization (DNP) and 10 NMR signals detection system for the polarization measurement
Unit Resolution for a Subclass of the Ackermann Class
No full textThe Ackermann class and the Gödel class are typical subclasses of pure first-order logic. The unsatisfiability problems for the Ackermann class and the Gödel class of formulas are decidable and resolution strategies to the unsatisfiability problems for the Ackermann class and the Gödel class were constructed by W. H. Joyner. Applying unit resolution of C. L. Chang, we construct a preprocessor to Joyner's resolution strategy for a subclass of the Ackermann class, since his strategy may necessitate too much time and space from the practical point of view. In this paper, we describe an algorithm to decide whether there is a unit resolution refutation from a set of clauses in a subclass ACK₂ of the Ackermann class, in which at most two literals with variables appear in each clause. In this algorithm, we represent the unit clause resolvents generated by unit resolution by means of finite automata. Also, we transform the decision problem of a unit resolution refutability for ACK₂ to the emptiness problem of intersections of two regular languages. We give the time complexity and the space complexity of the constructed algorithm. This result is an extension of the result by N. D. Jones namely that it can be decided in deterministic polynomial time whether or not ther is a unit resolution refutation for the propositional logic
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