Advanced Materials Research Vols. 602-604

Abstract: Tm³⁺ and Dy³⁺ co-doped zinc-aluminum phosphate glasses were prepared in this study. Judd-Ofelt theory has been used to evaluate the three intensity parameters Ω₂, Ω₄ and Ω₆ form the experimental oscillator strengths. The luminescence properties were investigated by excitation and emission spectra. White light emission could be induced by combined blue and yellow bands under UV excitation, and the variety of excitation wavelength could change the luminescence color.

Abstract: This paper has introduced the concept of complex refractive index and studied the effects of material absorption on the total reflection tunneling characteristics of photonic crystals by employing the characteristic matrix method. Through numerical computation, changes of the total reflection tunneling peak of photonic crystals along with the extinction coefficient and periodical optical thickness of the materials have been studied. The peak height of the total reflection tunneling decreases with the increase of the extinction coefficient, while the frequency of the total reflection tunneling peak is free from the extinction coefficient. Moreover, the frequency and bandwidth of the total reflection tunneling decrease with the increase of the periodical optical thickness.

Abstract: Electromagnetic parameters and absorbing properties of fiber absorbents (carbon fiber, SiC fiber and polycrystalline iron fiber) were introduced. The influences of the arrangement, thickness and content of the fibers on radar absorbing property were summarized. New development directions of the fiber absorbents were also indicated.

Abstract: Gd_0.6BaB₉O₁₆: Eu³⁺_0.4 red phosphors were prepared by sol-gel technique. The different polyethylene glycols (PEGs) were added to control the particle size ofGd_0.6BaB₉O₁₆: Eu³⁺_0.4. The particle distribution and the relationship between the particle size and the luminescence properties of the phosphors were investigated. PEGs have no influence on the structure ofGd_0.6BaB₉O₁₆: Eu³⁺_0.4, but the particle size is changed with different molecular weight of PEGs. And the relative intensity of excitation peak and emission peak ofGd_0.6BaB₉O₁₆: Eu³⁺_0.4phosphor are reduced by adding PEG, due to the particle size effects.

Abstract: Fuzzy ball drilling fluids have been developed in order to effectively control lost circulation during CBM drilling. Depending upon fuzzy balls and colloids in fuzzy balls, the fuzzy ball drilling fluids changed their shapes and properties to completely plug underground heterogeneous seepage channels so as to strengthen the pressure bearing capacity of formations. This paper describes the available features of the fuzzy ball drilling fluid including efficient plugging, good carrying and suspension, formation damage control, compatible weighted by any weighted materials without auxiliary equipment. The fuzzy ball drilling fluids can finish drilling in low pressure natural gas zone, control CBM leakage; control the natural fractures, drilling in different pressures in the same open hole, combination with the air drilling mode, etc. during Ordos CBM drilling. The fuzzy ball drilling fluid will not affect down-hole motors and MWD. The fuzzy ball drilling fluid will be blend simply as conventional water based drilling fluids. The existing CBM drilling equipment can completely meet the fuzzy ball drilling mixing and it is maintained conveniently. The fuzzy ball drilling fluid is the efficient drilling fluid.

Abstract: Micro-environments of shoes chamber after strenuous exercise were simulated by using self-made experimental device. Under the different conditions of temperature and humidity, moisture absorption, water transmissibility, water retention and moisture liberation of stitch-bonded fabrics with different content of hemp was tested. According to multiple properties of the moisture-absorption and quick-drying, tested performance of five aspects were used to build the evaluation system about it. TOP-SIS (Technique for Order Preference by Similarity to Ideal Solution) and coefficient of variation method can calculate the degree of closeness of actual values and ideal values so as to establish a comprehensive evaluation method. The results show that when content of hemp is nearly 40%, shoe’s lining of stitch-bonded materials can obtain high performance, which can meet the requirement for shoe’s lining.

Abstract: Crystallization is a universal phenomenon in modern industry and has been developed into a core discipline. Investigation of the crystal formation has also increasingly become a vital subject in the field of materials science and technology. The crystal shape may be successfully varied by controlling its crystallization conditions, but there is far less understanding of how the crystal shape is modified. Thermodynamics of crystal growth behavior was developed to investigate the ideal shape of inorganic crystals on the basis of structural analysis of chemical bonds. The present work can help us to comprehend the crystal growth process and further guide the manipulation of crystal shape.

Abstract: A balloon filled with electron gas model was built to simulate metal for calculating its bulk elastic. Electron gas obeyed Fermi-Dirac distribution and satisfied with theory of ideal gas. Expression of metal bulk elastic modulus was derived, and the comparison between the new method given in this paper with current method according to theory of atom potential energy on calculation accuracy was also given. It showed that, pressure of electron gas closely related to bulk elastic modulus, and maybe it was the major factor in determining bulk elastic modulus of metal; not all of valence electrons of atom in metal became conduction electrons to form the electron gas; new model of present work is superior to traditional method based on calculating derivative of potential energy.

Abstract: The interaction of the shuffle 60° dislocation with a regular chain of hexavacancies was investigated via the molecular dynamics simulation with Stillinger-Weber potential. The results show that an attraction exists between the shuffle 60° dislocation and hexavacany. The attraction energy is dependent obviously upon the hexavacancy concentration. The dislocation can overcome the pinning of vacancies under a critical resolved shear stress, and a linear relationship is found between the critical stress and hexavacancy concentration.

Abstract: A rhenium (I) complex containing the new spriodipyridine-type ligand, spiro[cyclopenta[1,2-b:5,4-b']dipyridine-5,9'-fluorene], was investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT). The HOMO is  character, while the LUMO is π* orbitals of the pyridine ligands. The lowest lying absorption band of the complexes has the HOMO-2 → LUMO transition configurations resulting in the MLCT/LLCT characters