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61.
62.
Mustafa Usta Derya Ustaomer Saip Nami Kartal Sedat Ondaral 《International journal of molecular sciences》2009,10(6):2789-2797
In this study, the effects of various boron compounds on the termite resistance of MDF panels were evaluated. Either borax (BX), boric acid (BA), zinc borate (ZB), or sodium perborate tetrahydrate (SPT) were added to urea-formaldehyde (UF) resin at target contents of 1%, 1.5%, 2% and 2.5% based on dry fiber weight. The panels were then manufactured using 12% urea-formaldehyde resin and 1% NH4Cl. MDF samples from the panels were tested against the subterranean termites, Coptotermes formosanus Shiraki. Laboratory termite resistance tests showed that all samples containing boron compounds had greater resistance against termite attack compared to untreated MDF samples. At the second and third weeks of exposure, nearly 100% termite mortalities were recorded in all boron compound treated samples. The highest termite mortalities were determined in the samples with either BA or BX. Also, it was found that SPT showed notable performance on the termite mortality. As chemical loadings increased, termite mortalities increased, and at the same time the weight losses of the samples decreased. 相似文献
63.
Chinatsu Okamura Takashi Ueda Kazuhiro Hasezaki 《Journal of Electronic Materials》2010,39(9):2172-2175
Single-phase β-Zn4Sb3 materials were prepared by mechanical grinding (MG). Source materials for the Zn4Sb3 ingots were prepared using three different processes after the direct melting of constituent elements. In process 1, the
ingot was obtained by quenching the melt in water within an evacuated quartz ampoule. In process 2, the ingot was heat-treated
for 100 h at 723 K after process 1. In process 3, the ingot was heat-treated for a total of 200 h in two stages at 723 K and
673 K after process 1. The resultant ingots were mechanically ground and sintered at 623 K by hot pressing. The sintered materials
were characterized by x-ray diffraction, differential thermal analysis (DTA), and thermoelectric property measurements. The
thermal conductivity of the sintered materials was 0.88 W m−1 K−1 at room temperature, being slightly lower than that reported for the materials prepared by a conventional method. Results
indicate that the dimensionless figure of merit of the single-phase β-Zn4Sb3 ranged from 1.06 to 1.31 at 573 K. 相似文献
64.
Rintaro Aoyagi Hiroaki TakedaSoichiro Okamura Tadashi Shiosaki 《Materials Research Bulletin》2003,38(1):25-32
The crystal structure of Na0.5Bi2.5Nb2O9 was refined from its powder X-ray diffraction (XRD) data. Sodium bismuth niobate at 23 °C is orthorhombic, A21am, with a=5.4998(3) Å, b=5.4602(2) Å, c=24.952(1) Å, and Z=4. The piezoelectric properties were investigated using the dense bulk ceramics. The electromechanical coupling coefficients (kij) and electrical quality factors (Qm) are k31=3.2%, kt=10.0%, and Qm=3800. Single crystals were also grown from stoichiometric melts using a slow cooling technique. The dielectric and ferroelectric properties of the crystal indicates that a spontaneous polarization clearly occurs in the crystallographic a-b plane. 相似文献
65.
The interaction of Si3N4 with chromium was investigated under an argon or nitrogen atmosphere at temperatures from 773–1573 K. Reaction rates were determined by thermogravimetric analysis, and reaction products were examined by X-ray diffraction. Cr2N, Cr3Si, Cr5Si3 and CrSi were produced under argon, while reaction products under nitrogen were Cr2N, CrN and Cr3Si. Possible reactions between Si3N4 and chromium have been discussed thermodynamically. The initial rate obeyed a linear rate law. When chromium particles were coated with the reaction layer, the rate was described by a parabolic rate law. The reaction mechanism and the rate-determining step have been proposed. 相似文献
66.
Chemical stimulation techniques for geothermal wells: experiments on the three-well EGS system at Soultz-sous-Forêts,France 总被引:1,自引:0,他引:1
Rock matrix stimulation is a method of enhancing well production or injection within a broad range of challenging environments, varying from naturally fractured limestones to sandstones with complex mineralogy. A common and often successful stimulation option, matrix acidizing, utilizes acids that react and remove mineral phases restricting fluid flow. Reviewed is the technology of chemical treatments available for oil, gas and geothermal wells and the key elements and results of the chemical reservoir stimulation program at the Soultz-sous-Forêts, France, Enhanced Geothermal System Project. 相似文献
67.
68.
Sasaki K. Tomaru T. Ajima Y. Ogitsu T. Araoka O. Higashi N. Iida M. Kasami K. Kimura N. Makida Y. Nakamoto T. Ohhata H. Okamura T. Sugawara S. Tanaka K. Yamamoto A. 《Applied Superconductivity, IEEE Transactions on》2008,18(2):142-145
Magnetic field measurements have been performed for the first full-scale magnet system assembled with the cryostat for the J-PARC proton beam line of neutrino experiment. In the measurement system, the probe position with respect to magnet central axis is measured by a Helium Neon laser and a position sensitive detector, PSD, in order to obtain an exact dipole field strength. Errors associated with the PSD misalignment and influences on the PSD signals by the magnetic field were evaluated. The measured dipole components approached to the design values by compensating those with the probe position. The latest beam simulation indicated that the measured values of magnetic field were good enough for the primary proton beam transport. 相似文献
69.
As an innovative approach to providing physical demonstrations in the engineering classroom, we present the haptic paddle: a low‐cost, single‐axis force‐feedback joystick. Using the paddle in the laboratory component of an undergraduate course on dynamic systems, students not only learned to model and analyze dynamic systems, but they also felt the effects of phenomena such as viscous damping, stiffness, and inertia. By interacting with virtual environments using their sense of touch, students improved their understanding of dynamic systems, modeling and control. In addition, the paddles added entertainment and excitement to the course. In this paper, we describe the purpose and design of the haptic paddle, show examples of how the paddle was integrated into the course, and present the results of preliminary student evaluations. 相似文献
70.
Developmental expression and location of IGF-I and IGF-II mRNA and protein in skeletal muscle 总被引:1,自引:0,他引:1
To investigate the role of IGF in muscle development in vivo, developmental expression and location of IGF-I and -II protein and mRNA were examined in fetal, postnatal, and adult skeletal muscle. Muscle tissue was collected from 30-, 44-, 59-, 68-, 75-, 89-, and 109-d porcine fetuses, 21-d neonatal pigs, and 6-mo-old (adult) pigs. Relative amounts of IGF-II mRNA peaked (P < .05) in 59-d fetal muscle and decreased thereafter. Inversely, muscle IGF-I expression increased (P < .05) to maximal levels around birth. For in situ hybridization, frozen muscle tissue sections (10 microm) were hybridized with a hydrolyzed form of the same riboprobes or incubated with polyclonal or monoclonal antibodies to IGF-I or -II, respectively. The majority of IGF-I and IGF-II mRNA was localized to developing muscle fibers, whereas little signal was found in the surrounding connective tissues. Immunofluorescent localization of IGF-I and -II confirmed that muscle IGF are present in developing muscle fibers. Collectively, these data show that IGF-I and -II are expressed and produced primarily in muscle cells within developing muscle tissue and support the hypothesis that IGF-I and -II modulate fetal muscle development. 相似文献