High-frequency auditory filter shape for the Atlantic bottlenose dolphin

High-frequency auditory filter shapes of an Atlantic bottlenose dolphin (Tursiops truncatus) were measured using a notched noise masking source centered on pure tone signals at frequencies of 40, 60, 80 and 100?kHz. A dolphin was trained to swim into a hoop station facing the noise/signal transducer located at a distance of 2?m. The dolphin's masked threshold was determined using an up-down staircase method as the width of the notched noise was randomly varied from 0, 0.2, 04, 0.6, and 0.8 times the test tone frequency. The masked threshold decreased as the width of the notched increased and less noise fell within the auditory filter associated with the test tone. The auditory filter shapes were approximated by fitting a roex (p,r(r)) function to the masked threshold results. A constant-Q value of 8.4 modeled the results within the frequency range of 40 to 100 kHz relatively well. However, between 60 and 100?kHz, the 3?dB bandwidth was relatively similar between 9.5 and 10?kHz, indicating a constant-bandwidth system in this frequency range The mean equivalent rectangular bandwidth calculated from the filter shape was approximately 16.0%, 17.0%, 13.6% and 11.3% of the tone frequencies of 40, 60, 80, and 100?kHz.     

在Al-P-Ti-Si-O催化剂上由甲醇和邻苯二酚合成愈创木酚的研究

采用非均匀沉淀法制备了Al1P1.30TiaSib(a=0-0.51,b=0-0.90）复合催化剂,研究了邻苯二酚与甲醇在该催化剂上的气相o-甲基化反应。结果表明,催化剂组成、相结构和表面性质对催化剂的活性和选择性有很大影响。其中Al1P1.30Ti0.30si0.17催化剂的愈创木酚收率最高,在反应温度为553K时,邻苯二酚转化率和愈创木酚收率分别为92%和86%。     

Dual-Functional Mesoporous Copper(II) Metal-Organic Frameworks for the Remediation of Organic Dyes

By using tritopic and ditopic organic linkers derived from the same 2,4,6-triphenylpyridine core, copper(II) metal-organic frameworks with different three-dimensional structures have been successfully synthesized under ambient conditions. The crystalline framework, ^PTB MOF ([Cu₃(PTB)₂(H₂O)₃]_n, where H₃PTB=4,4′,4′′-(pyridine-2,4,6-triyl)tribenzoic acid, was observed to be mesoporous in nature and exhibited dual functionality in the removal of organic dyes. While cationic dyes such as methylene blue and malachite green, which are of different sizes, were adsorbed by ^PTB MOF ; anionic dyes such as tartrazine could be effectively degraded in a photo-Fenton-like reaction catalyzed by the MOFs under irradiation with visible light.     

Application of the Sc-theory to structural design

Fracture mechanics is a powerful tool in the hands of a knowledgeable engineer. It offers the designer and structural analyst quantitative guidelines to the design, evaluation and maintenance of high-performance fracture-resistant structures in terms of material selection, safe operating stress levels, and quality assurance standards. However, it must be applied properly and integrated with the other design requirements early in the design phase to reap the desired benefits. In this connection, the strain-energy-density factor theory, or the S_c-theory, is applied in this paper to illustrate the principles of fracture mechanics methodology towards the design of a cylindrical shell structure under complex loading conditions. The versatility of this theory in selecting competing structural materials and in determining safe operating stress levels, allowable loads, factors of safety, damage tolerance and safe crack propagation life are highlighted.     

Quantum chemistry study on B14, B,and B14H

The structure of B₁₄, B, and B₁₄H in octahedral symmetry has been investigated by ab initio calculations at the STO-3G and 4–31G levels. The relationship of molecular orbitals among them has been analyzed and it can be found that the number of valence bonding orbitals of high borane obeys the Wade rule. The similarities and difference between boron clusters and carbon clusters are also discussed. © 1994 John Wiley & Sons, Inc.     

Synthesis and Characterization of Surfactant‐encapsulated Polyoxoanions: [(CnH2n + 1)2N(CH3)2]12[Mo36(NO)4Om(H2O)16] (n = 12, 18)

By employing electrostatic interaction as driving force, an organic/inorganic composite with positively charged dimethyl dialkyl‐chain ammonium surfactants encapsulating negatively charged (NH₄)12[Mo₃₆(NO)₄O₁₀₈(H₂O)₁₆]. 33H₂O polyoxoanion was prepared. The structure of the novel organic/inorganic hybrid particle with hydrophilic core and hydrophobic shell in a defined stoichiometric ratio was confirmed by element analysis, ¹H NMR and FT‐IR spectra. The property of the polyoxoanion was changed due to the encapsulation and it can be dissolved in organic solvent such as chloroform, benzene and toluene, but not dissolved in water.     

Reduction of plutonium to the bivalent state

Conclusions The existence of the bivalent state of plutonium and the standard oxidation potential of the Pu³⁺/Pu²⁺ couple, equal to –2.59 V, have been established for the first time.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 818–820, April, 1982.     

Regularization of a final value problem for a nonlinear biharmonic equation

In this paper, we consider the nonlinear biharmonic equation. The problem is ill‐posed in the sense of Hadamard. To obtain a stable numerical solution, we consider a regularization method. We show rigourously, with error estimates provided, that the corresponding regularized solutions converge to the true solution strongly in uniformly with respect to the space coordinate under some a priori assumptions on the solution.