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排序方式: 共有234条查询结果,搜索用时 218 毫秒
121.
J. Wrzesiński R. Broda B. Fornal W. Królas T. Pawłat M. P. Carpenter R. V. F. Janssens D. Seweryniak S. Lunardi C. A. Ur G. Viesti M. Cinausero N. Marginean K. H. Maier 《The European Physical Journal A - Hadrons and Nuclei》2003,20(1):57-58
New high-spin states were identified in the 205Tl isotope produced in deep-inelastic heavy-ion reactions. The expected 29/2 + yrast state and 35/2- isomeric state with 235 ns half-life were located above the 2.6 s isomer known from previous studies. Above this isomer a 7092 keV level was interpreted as a 41/2 + state arising from the coupling of the octupole vibration of the 208Pb core with the three-hole structure of the 35/2- isomer.Received: 20 January 2003, Revised: 10 March 2003, Published online: 2 March 2004PACS:
21.60.Cs Shell model - 23.20.Lv Gamma transitions and level energies - 27.80. + w
- 25.70.Lm Strongly damped collisions 相似文献
122.
An elementary notion of master-slave synchronization that accepts multimodal synchronization is introduced. We prove rigorously that the attractor of a coupled pair in a regime of multimodal synchronization is the graph of a multivalued function. Our framework provides the theoretical basis for some practical tools for detection of multimodal synchrony in experiments. Results are illustrated with the analysis of experiments with coupled electronic oscillators. 相似文献
123.
Diana?Uría Fernández Valérie?Geoffroy Mathias?Sch?fer Jean-Marie?Meyer Herbert?BudzikiewiczEmail author 《Monatshefte für Chemie / Chemical Monthly》2003,134(10):1421-1431
Summary. The structural revision on the basis of spectroscopic and degradation results of several pyoverdins from Pseudomonas spp. is reported. Siderotyping studies by the isoelectrofocusing technique and by ferri-pyoverdin uptake experiments had prompted a re-investigation of some structures proposed in the literature.Received June 26, 2003; accepted July 7, 2003
Published online September 11,2003 相似文献
124.
The current research work presents a novel nonionic curing agent (AEDA) synthesized by utilizing ethylene glycol diglycidyl ether (EGDE), 3,4-dimethoxyaniline (DI), and triethylenetetramine (TETA). Infrared spectroscopy and nuclear magnetic resonance spectroscopy were used to characterize the structure of AEDA curing agent. Non-isothermal scanning calorimetry was used to determine the activation energy and curing conditions of epoxy resin in the curing process. An impact testing machine, a tensile testing machine and a scanning electron microscope (SEM) were used to analyze the impact strength, tensile strength, bending strength, and micromorphology of the AEDA/E-51 system with different mass ratios. The results show that AEDA is an effective high-temperature curing agent. For the AEDA/E-51 system with the optimal mass ratio of 10:100, the best curing temperature is 92.15°C, and the post-curing temperature is 135.65°C. Furthermore, the apparent activation energy (Ea) of 1670 J/mol, the pre-exponential factor (A) of 3.7 × 10?4, and the reaction series (n) value of 0.76 are obtained for the AEDA/E-51 system. The impact strength of AEDA/E-51 epoxy resin polymer is 7.82 kJ/m2, tensile strength is 14.2 MPa, and bending strength is 18.92 MPa. The micromorphological results of the AEDA/E-51 system are consistent with the results of DSC test and mechanical properties test. Hence, this study provides theoretical support for the practical applications of AEDA as curing agent. 相似文献
125.
Khalil Ur Rehman Wasfi Shatanawi Taqi A. M. Shatnawi 《Numerical Methods for Partial Differential Equations》2023,39(1):678-695
The flow field in a convergent–divergent engulfment along with the installation of infinite cylinders as an obstacle results in non-linear partial differential equations and the scientific computation in this regard remains a challenging task. The present attempt is the numerical motivation in this direction to evaluate the flowing liquid stream in the convergent–divergent channel at a low Reynolds number. From the left wall, the liquid stream move with the parabolic profile and have interaction with the case-wise installation of infinite cylinders in the left vicinity of the convergent–divergent throat. The differential system is constructed for the flow field in the channel and hybrid meshed finite element method is utilized to report the numerical solution. A comparative study is enclosed for the hydrodynamic forces faced by obstructions in the left region of the convergent–divergent throat. The drag coefficient for a triangular cylinder acting as an obstruction is higher than that of a circular hitch. In comparison to both triangular and circular hitches, the square-shaped obstacle suffered the most drag force. Considering drag coefficient one can extend this work to obtain information for the real behavior of the vehicle toward air flow and may conclude findings toward reduction of fuel consumption. 相似文献
126.
Wasim Ul Bari Najeeb Ur Rehman Ajmal Khan Sobia Ahsan Halim Ye Yuan Mark A.T. Blaskovich Zyta M. Ziora Muhammad Zahoor Sumaira Naz Riaz Ullah Amal Alotaibi Ahmed Al-Harrasi 《Molecules (Basel, Switzerland)》2021,26(7)
In the study, two novel compounds along with two new compounds were isolated from Grewia optiva. The novel compounds have never been reported in any plant source, whereas the new compounds are reported for the first time from the studied plant. The four compounds were characterized as: 5,5,7,7,11,13-hexamethyl-2-(5-methylhexyl)icosahydro-1H-cyclopenta[a]chrysen-9-ol (IX), docosanoic acid (X), methanetriol mano formate (XI) and 2,2’-(1,4-phenylene)bis(3-methylbutanoic acid (XII). The anticholinesterase, antidiabetic, and antioxidant potentials of these compounds were determined using standard protocols. All the isolated compounds exhibited a moderate-to-good degree of activity against acetylcholinesterases (AChE) and butyrylcholinesterase (BChE). However, compound XII was particularly effective with IC50 of 55 μg/mL (against AChE) and 60 μg/mL (against BChE), and this inhibitory activity is supported by in silico docking studies. The same compound was also effective against DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid) radicals with IC50 values of 60 and 62 μg/mL, respectively. The compound also significantly inhibited the activities of α-amylase and α-glucosidase in vitro. The IC50 values for inhibition of the two enzymes were recorded as 90 and 92 μg/mL, respectively. The in vitro potentials of compound XII to treat Alzheimer’s disease (in terms of AchE and BChE inhibition), diabetes (in terms of α-amylase and α-glucosidase inhibition), and oxidative stress (in terms of free radical scavenging) suggest further in vivo investigations of the compound for assessing its efficacy, safety profile, and other parameters to proclaim the compound as a potential drug candidate. 相似文献
127.
128.
C. Wheldon Tz. Kokalova W. von Oertzen S. Thummerer H. G. Bohlen B. Gebauer A. Tumino T. N. Massey G. de Angelis M. Axiotis A. Gadea Th. Kröll N. Mărginean D. R. Napoli M. De Poli C. Ur D. Bazzacco S. M. Lenzi C. Rossi Alvarez S. Lunardi R. Menegazzo P. G. Bizzeti A. M. Bizzeti-Sona 《The European Physical Journal A - Hadrons and Nuclei》2005,26(3):321-326
Cluster states up to 12 MeV in the stable light nucleus 21Ne, based on the 16O + n + α molecular configurations, have been populated in the incomplete-fusion reaction 16 8O(73Li, np)2110Ne at 29.4 MeV. The observation of both intra- and inter-band transitions leads to a re-interpretation of some levels in the
Kπ =
- and Kπ =
- bands. The implications of this re-ordering on the octupole doublet bands are examined. The data allow a more accurate determination
of some previously uncertain level energies. The “missing” Iπ =
- level is also discussed. 相似文献
129.
Alberto Menéndez García José Enrique Sánchez Uría Alfredo Sanz-Medel M. Carmen Quintero Ortega José Cotrino Bautista 《Mikrochimica acta》1992,106(3-6):277-285
A sensitive and selective indirect determination of iodide by inductively coupled plasma emission spectrometry (ICP-AES) based on the principle of tandem on-line continuous separations as an alternative means of introducing samples into plasmas is proposed. Iodide is continuously extracted as an ion-pair into xylene by mixing the sample with Hg(II) and dipyridil solutions. The organic phase (containing the analyte in [Hg(Dipy)2]I2 form) is on-line continuously mixed with NaBH4 (in DMF) and acetic acid solutions. Mercury vapour continuously generated from this organic phase is separated in a classical U-type gas-liquid separation device. The system has been optimized for the continuous extraction of KI, for the direct generation of cold mercury vapour from xylene and for the final ICP-AES determination of mercury. The optimised method has been applied to the determination of iodide (detection limit 20 ng/ml of iodide) in table salt and in synthetic samples. Very good agreement between found and certified results was observed. The usefulness and convenience of such alternative sample chemical pretreatment/presentation to the ICP is thus demonstrated for indirect determinations to be carried out by atomic spectroscopy methods. 相似文献
130.
Fazal Rahim Muhammad Ali Shifa Ullah Umer Rashid Hayat Ullah Muhammad Taha Muhammad Tariq Javed Wajid Rehman Aftab Ahmad Khan Obaid Ur Rahman Abid Muhammad Bilal 《中国化学快报》2016,27(5):693-697
Bis-thiobarbiturate derivatives 1–15 have been synthesized, characterized by1 HNMR and EI-MS and screened for urease inhibition. All compounds showed various degree of urease inhibitory activity with IC_(50) values ranging 7.45 0.12 74.24 0.81 mmol/L while the standard thiourea behaved normally(IC_(50) = 21.10 0.12). Compounds 1(IC_(50) = 7.45 0.12 μmol/L), 9(IC_(50) = 18.17 1.03 μmol/L) and 13(IC_(50) = 8.61 0.45 μmol/L) showed excellent urease inhibitory activity in the series. Molecular modeling studies were performed to understand the binding site with the bimetallic nickel center of the enzyme.Structure-activity relationship has also been established for these compounds. This study identified bisthiobarbiturate as a novel class of urease inhibitors. 相似文献