Up to 5 mol% Al2O3 was added to 9 mol% Y2O3-stabilized ZrO2, and the roles of Al2O3 were systematically studied by means of the complex impedance approach, the positron annihilation technique, SEM, TEM, and electron p...
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Up to 5 mol% Al2O3 was added to 9 mol% Y2O3-stabilized ZrO2, and the roles of Al2O3 were systematically studied by means of the complex impedance approach, the positron annihilation technique, SEM, TEM, and electron probe microanalysis from the following aspects: (1) the existence of forms of Al2O3 in ZrO2, (2) the effects of Al2O3 on the microstructure of ZrO2, (3) the effects of Al2O3 on the resistance of ZrO2, (4) the microstructure and property changes of ZrO2 with Al2O3 addition during ageing at 940 degrees C. Two types of grain boundary phase, crystal and amorphous, were discovered. The Al2O3 segregation at grain boundaries can promote the mobility of the grain boundaries and thus results in a low density, because of entrapped pores. The Al2O3 addition decreases the grain-boundary resistance in two ways: to scavenge the SiO2 and CaO located at grain boundaries, and to form crystal grain-boundary phases with very high crystal defect concentrations. Ordered microdomains of Zr3Y4O12 were precipitated from ZrO2 grains during ageing, and aluminium was found to facilitate the precipitation.
Doped SrTiO3 capacitor-varistor multifunctional ceramics were fabricated by a single sintering process. AC complex impedance analysis was performed to investigate electrical features of grains and grain boundaries for...
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Doped SrTiO3 capacitor-varistor multifunctional ceramics were fabricated by a single sintering process. AC complex impedance analysis was performed to investigate electrical features of grains and grain boundaries for both as-reduced ceramic and reoxidized ceramics. The results showed that the as-reduced ceramic exhibited inductive response at high frequencies above 2 MHz, which is attributed to the contribution of electron behavior in semiconducting grains. The high frequency inductive response disappeared in impedance plots of reoxidized ceramics.
We use transient terahertz photoconductivity measurements to demonstrate that upon optical excitation of CH_(3)NH_(3)PbI_(3)perovskite,the hole transfer from CH_(3)NH_(3)PbI_(3)into the organic hole-transporting mater...
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We use transient terahertz photoconductivity measurements to demonstrate that upon optical excitation of CH_(3)NH_(3)PbI_(3)perovskite,the hole transfer from CH_(3)NH_(3)PbI_(3)into the organic hole-transporting material(HTM)Spiro-OMe TAD occurs on a sub-picosecond ***-order recombination is the dominant decay pathway at higher photo-excitation fluences as observed in neat CH_(3)NH_(3)PbI_(3)*** contrast,under similar experimental conditions,second-order recombination weakly contributes the relatively slow recombination between the electrons in the perovskite and the injected holes in HTM,as a loss mechanism at the CH_(3)NH_(3)PbI_(3)/Spiro-OMe TAD *** results offer insights into the intrinsic photophysics of CH_(3)NH_(3)PbI_(3)-based perovskites with direct implications for photovoltaic devices and optoelectronic applications.
Half Heusler materials exhibit excellent thermoelectric and mechanical properties,rendering them potential candidates for advanced thermoelectric ***,the developments on interrelated devices are impeded by their inher...
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Half Heusler materials exhibit excellent thermoelectric and mechanical properties,rendering them potential candidates for advanced thermoelectric ***,the developments on interrelated devices are impeded by their inherent brittleness and limited ***,it exists the potential ductility on half Heusler materials with face-centered cubic sub-lattices through the expectation of the occurrence of shear-induced‘catching bonds’which can result in excellent ductility on other face-centered cubic materials.
The wetting behavior of molten Cu on the B_(4)C-xTiB_(2)ceramic composites was investigated in this *** results show that the contact angle of molten Cu alloy on B_(4)C-TiB_(2)ceramic composites is linear with the com...
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The wetting behavior of molten Cu on the B_(4)C-xTiB_(2)ceramic composites was investigated in this *** results show that the contact angle of molten Cu alloy on B_(4)C-TiB_(2)ceramic composites is linear with the composition rate of TiB_(2)or B_(4)C while the temperature is in the range of 1300 to 1350℃,consistent with the expectation of the commonly used theoretical ***,a nonlinear relationship between the contact angle and the composition rate unexpectedly occurred at temperatures ranging from 1400 to 1500℃.The big difference of the contact angles between the molten metal and the components in the composites was found to be the key *** result identifies that the commonly used theoretical method only works at a limited difference of the contact angle of the liquid on the different phases in the composites,and fails at a big difference.
A new niobate compound with the chemical composition of Ba5LiTiNb9O30 was synthesized by doping Li+ into the system BaO-TiO2-Nb2O5 in conventional solid state reaction method. The crystalline structure was determined ...
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A new niobate compound with the chemical composition of Ba5LiTiNb9O30 was synthesized by doping Li+ into the system BaO-TiO2-Nb2O5 in conventional solid state reaction method. The crystalline structure was determined by X-ray diffraction analysis (XRD). The results showed that crystal structure of Ba5LiTiNb9O30 belongs to tetrago-nal tungsten bronze structure with space group P4bm and its unit cell parameters: a=b=1.2512(2) nm, c=0.4008(5) nm. The microstructure of reaction products was observed by scanning electron microscopy (SEM).
Tungsten carbide (WC) targets with low cobalt (Co) content (0.1 - 0.2 wt.%) were prepared by hot-press sintering at 1700°C for 60 minutes in argon, from element starting powders of tungsten, cobalt and carbon. Re...
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Tungsten carbide (WC) targets with low cobalt (Co) content (0.1 - 0.2 wt.%) were prepared by hot-press sintering at 1700°C for 60 minutes in argon, from element starting powders of tungsten, cobalt and carbon. Results show that the as-fabricated targets yield relatively high relative density above 99% and high HRA above 92. WC with low Co content is formed easily than pure WC The hot-press sintering process, while element starting powders are used, is an in-situ reaction technique for accelerating the WC's diffusion rate to obtain a dense sintered body.
Pulse current heating (PCH) was used to join Ti-6Al-4V alloy at two cases of with die and without die. Hot-pressing (HP) method was used to provide a comparison between the two methods. Microstructures near the contac...
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Pulse current heating (PCH) was used to join Ti-6Al-4V alloy at two cases of with die and without die. Hot-pressing (HP) method was used to provide a comparison between the two methods. Microstructures near the contacting surfaces were observed in optical microscope. Temperature distribution was analyzed. After joining, the tensile properties of the samples were evaluated. Experimental results show that grains and phases grow transversely on contacting surfaces, which makes two parts into a whole with a certain of tensile strength. PCH joining is a different temperature joining method. The highest temperature is located at the interface. The comparison of tensile strengths of samples joined by the two methods indicates that joining temperature and holding time needed by PCH are lower and less than those needed for HP.
Rhizama Chuanxiong is a kind of traditional medicinal herb used to promote blood circulation and eliminate wind to relieve pain. In this work, nano Rhizoma Chuanxiong particles were successfully prepared by high speed...
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Rhizama Chuanxiong is a kind of traditional medicinal herb used to promote blood circulation and eliminate wind to relieve pain. In this work, nano Rhizoma Chuanxiong particles were successfully prepared by high speed centrifugal sheering (HSCS) pulverizer. The influence of processing parameters on the size of Rhizama Chuanxiong particles and the different properties between nano Rhizoma Chuanxiong particles and original fine powder were systematically studied by ZetaPALS light scattering granulometric analyzer and optical microscope. The content of effective ingredient tetramethylpyrazine (TMP) was determined by high-performance liquid chromatography (HPLC). The results illustrate that general Rhizama Chuanxiong powder can be ultrafinely ground to nanometer within 50 min, and the cellular tissues of Rhizoma Chuanxiong are broken into pieces and dispersed stably and homogeneously after being ultrafinely ground. In addition, the active ingredients can dissolve out directly and fully, and the extraction ratio of TMP is increased 32.2% by HSCS processing.
Antimony doped tin oxide（ATO） thin films have been prepared by pulsed laser deposition（PLD） *** intrinsic effect of Sb dopant,including the Sb content,transition degree between Sb（3＋） and Sb（5＋） and crystall...
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Antimony doped tin oxide（ATO） thin films have been prepared by pulsed laser deposition（PLD） *** intrinsic effect of Sb dopant,including the Sb content,transition degree between Sb（3＋） and Sb（5＋） and crystallinity on the electrical and optical properties of the ATO thin films is mainly *** is suggested that the transition degree of Sb（3＋） towards Sb（5＋）（Sb（5＋）/Sb（3＋） ratio） is determined by Sb *** the Sb content is increased to 12 at%,the Sb（5＋）/Sb（3＋） ratio reaches the highest value of 2.05,corresponding to the resistivity of 2.70×10（-3） Ω·***,the Burstein-Moss effect caused by the increase of carrier concentration is observed and the band gap of the ATO thin films is broadened to 4.0 eV when the Sb content is increased to 12 at%,corresponding to the highest average optical transmittance of 92%.Comprehensively considering the combination of electrical and optical properties,the ATO thin films deposited with Sb content of 12 at%exhibit the best properties with the highest ＂figure of merit＂ of 3.85×10（-3） Ω（-1）.Finally,an antimony selenide（Sb_2Se_3） heterojunction solar cell prototype with the ATO thin film as the anode has been prepared,and a power conversion efficiency of 0.83%has been achieved.
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