排序方式: 共有40条查询结果,搜索用时 406 毫秒
11.
Vesey RA Cuneo ME Bennett GR Porter JL Adams RG Aragon RA Rambo PK Ruggles LE Simpson WW Smith IC 《Physical review letters》2003,90(3):035005
Simulations of a double Z-pinch hohlraum, relevant to the high-yield inertial-confinement-fusion concept, predict that through geometry design the time-integrated P2 Legendre mode drive asymmetry can be systematically controlled from positive to negative coefficient values. Studying capsule elongation, recent experiments on Z confirm such control by varying the secondary hohlraum length. Since the experimental trend and optimum length are correctly modeled, confidence is gained in the simulation tools; the same tools predict capsule drive uniformity sufficient for high-yield fusion ignition. 相似文献
12.
Edens AD Ditmire T Hansen JF Edwards MJ Adams RG Rambo PK Ruggles L Smith IC Porter JL 《Physical review letters》2005,95(24):244503
To explore the validity of theories forwarded to explain the dynamics of hydrodynamic perturbations on high Mach number blast waves, we have studied the decay rate of perturbations on blast waves traveling through nitrogen gas. In our experiments, 1 kJ pulses from the Z-Beamlet laser at Sandia National Laboratories illuminated solid targets immersed in gas and created blast waves. The polytropic index implied by comparing experiment to theoretical predictions is compared to simulation results. 相似文献
13.
It has been found that the Fermi energy of thin single crystals of Cd3As2 increases to 0.25 eV on annealing under vacuum at 425°C and then decreases to below any previously reported value. The magneto optical measurements which yielded oscillations independent of photon energy were analysed in terms of Shubnikov de Haas oscillations and were consistent with the Bodnar model for the conduction band of Cd3As2. 相似文献
14.
Gong HY Rambo BM Karnas E Lynch VM Keller KM Sessler JL 《Journal of the American Chemical Society》2011,133(5):1526-1533
The tetracationic macrocycle cyclo[2](2,6-di(1H-imidazol-1-yl)pyridine)[2](1,4-dimethylenebenzene) hexafluorophosphate (1(4+)·4PF(6)(-)) acts as a large, flexible "molecular box" that supports the formation of environmentally responsive anion-induced pseudorotaxanes, as well as other extended structures, including metal-linked supramolecular polyrotaxanes. Specifically, the combination of the tetracation 1(4+) and bis-carboxylate guests derived from 4,4'-biphenyldicarboxylic acid and 2,6-naphthalenedicarboxylic acid results in the formation of pseudorotaxanes that respond to changes in environmental stimuli, including pH and temperature. The resulting structures can be "locked into place" via the addition of a metal-linker in the form of Ag(I); this gives rise to an ordered metal-linked polyrotaxane. The interpenetrated constructs described in this article were characterized in solution and in the solid state by one- and two-dimensional ((1)H and NOESY) NMR spectroscopy, as well as by mass spectrometry (ESI-MS) and single-crystal X-ray diffraction methods. 相似文献
15.
Ana Flvia Borsoi Josiane Delgado Paz Kenia Pissinate Raoní Scheibler Rambo Víctor Zajaczkowski Pestana Cristiano Valim Bizarro Luiz Augusto Basso Pablo Machado 《Molecules (Basel, Switzerland)》2021,26(5)
Tuberculosis (TB) has been described as a global health crisis since the second half of the 1990s. Mycobacterium tuberculosis (Mtb), the etiologic agent of TB in humans, is a very successful pathogen, being the main cause of death in the population among infectious agents. In 2019, it was estimated that around 10 million individuals were contaminated by this bacillus and about 1.2 million succumbed to the disease. In recent years, our research group has reported the design and synthesis of quinoline derivatives as drug candidates for the treatment of TB. These compounds have demonstrated potent and selective growth inhibition of drug-susceptible and drug-resistant Mtb strains. Herein, a new synthetic approach was established providing efficient and rapid access (15 min) to a series of 4-alkoxy-6-methoxy-2-methylquinolines using ultrasound energy. The new synthetic protocol provides a simple procedure utilizing an open vessel system that affords the target products at satisfactory yields (45–84%) and elevated purities (≥95%). The methodology allows the evaluation of a larger number of molecules in assays against the bacillus, facilitating the determination of the structure–activity relationship with a reduced environmental cost. 相似文献
16.
V. Hejny J. Weiß P. Achenbach J. Ahrens J.R.M. Annand R. Beck M. Kotulla B. Krusche V. Kuhr R. Leukel I.J.D. MacGregor V. Metag R. Novotny V. Olmos de León F. Rambo A. Schmidt M. Schumacher U. Siodlaczek H. Ströher F. Wissmann M. Wolf 《The European Physical Journal A - Hadrons and Nuclei》2002,13(4):493-499
The photoproduction of η-mesons from 2H and 4He has been studied for energies close to the production thresholds. The experiments were carried out with the tagged photon
beam of the Mainz MAMI accelerator. The η-mesons were detected via their two photon decays with the electromagnetic calorimeter
TAPS. Total cross-sections, angular and momentum distributions of the η-mesons have been determined for both reactions. The
total cross-sections in the threshold region show a large enhancement over the predictions of a participant-spectator model,
indicating significant final-state interaction effects. The results are compared to recent model calculations taking into
account nucleon-nucleon and nucleon-η final-state interaction effects on different levels of sophistication.
Received: 23 November 2001 / Accepted: 11 February 2002 相似文献
17.
It is well known that, for stepsize sufficiently small, compactattractors of ordinary differential equations persist underdiscretization. The present paper describes the structure ofthe discrete-time dynamical system obtained via discretizationon A(Mh)\Mh where Mh is the approximate attractor and A(Mh)is its domain of attraction. The existence of a smooth embeddinginto a continuous-time parallelizable flow is proved. The constructioncan be used to define sections for discretizations and can beinterpreted as a justification of the method of modified equations. 相似文献
18.
Renata Biegelmeyer Rafael Schröder Douglas F. Rambo Roger R. Dresch João L. F. Carraro Beatriz Mothes B 《Natural product research》2016,30(23):2734-2737
The purpose of this work was to study the cytotoxic effects of marine sponge Polymastia janeirensis, which has been observed in the field to release an orange substance that is toxic to fish. The result showed that aqueous extract (pH 7.0) was highly cytotoxic to glioma (U87) and neuroblastoma (SHSY5Y) cancer cell lines (IC50 < 1.0 μg/mL). In addition, this extract showed potent antioxidant and procoagulant (decreased the clotting time by 1.7-fold) activities. Interestingly, the cytotoxic effects were pH-dependent since the viability of the cancer cells was not affected with the extract (pH 5.5). The close similarity between the aqueous extract (pH 7.0) and the orange liquid that is released by the sponge indicates that this potential chemical defence of P. janeirensis deserves further investigation. 相似文献
19.
J. Weiß P. Achenbach J. Ahrens J.R.M. Annand R. Beck V. Hejny J.D. Kellie V. Kleber M. Kotulla B. Krusche V. Kuhr R. Leukel V. Metag V.M. Olmos de Léon F. Rambo A. Schmidt U. Siodlaczek H. Ströher F. Wissmann M. Wolf 《The European Physical Journal A - Hadrons and Nuclei》2001,11(4):371-374
Coherent photoproduction of η-mesons from the deuteron has been measured from threshold up to E
γ≈ 750 MeV using the photon spectrometer TAPS at the tagged photon facility at the Mainz microtron MAMI. For the first time,
differential coherent cross-sections have been deduced from the coincident detection of the η-meson and the recoil deuteron.
A missing-energy analysis was used for the suppression of background events so that a very clean identification of coherent
η-photoproduction was achieved. The resulting cross-sections agree with previous experimental results except for angles around
90° in the γd c.m. system where they are smaller. They are compared to various model calculations.
Received: 5 April 2001 / Accepted: 3 September 2001 相似文献
20.
Marcela Guiotoku Carlos R. Rambo Dachamir Hotza 《Journal of Thermal Analysis and Calorimetry》2014,117(1):269-275
In this work, cellulose-based renewable raw materials were hydrothermally carbonized in a microwave oven at 200 °C during 60, 120, and 240 min. The charcoals obtained were characterized by proximate analysis, gross calorific value, and thermogravimetric analysis on inert and oxidizing atmosphere. The values of fixed carbon were between 38 and 52 %. The mass loss between 300 and 470 °C was assigned to the thermal decomposition of cellulose, followed by the second stage between 470 and 740 °C, attributed to the thermal decomposition of lignin. The gross calorific values were between 22.60 and 27.12 MJ kg?1, which are comparable to those of charcoals and coals. 相似文献