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The surface morphology and combustion characteristics of micron-scale rice husks with different particle sizes were studied in detail by the fractal theory and thermogravimetric test. The calculation results by the box-counting dimension and erosion method were consistent with the actual data. The fractal dimensions first increased and then decreased with the rising particle sizes of rice husks. The largest fractal dimension and best combustion performance were found in 150 μm rice husk. The experiment results were verified finally by thermogravimetric tests, which were consistent with the theoretical results based on the fractal theory. The fractal theory of box-counting dimension and erosion provides a feasible method for studying biomass combustion characteristics.

In this study we report detailed magnetic property of the 4f-3d pseudo-quaternary Tb0.2Pr0.8(Fe0.4Co0.6)1.88C0.05 compound by detailed magnetization measurements. Very sharp magnetization jumps across the antiferromagnetic–ferromagnetic transition are observed below 3.0 K, and the number of jump-like transitions increases with decreasing temperature. The time-dependent magnetic relaxation, field sweep rate and cooling field dependence of magnetization jumps resemble the martensitic scenario. The number and occurrence of magnetization jumps are mainly determined by the competitions between the thermal fluctuation energy, elastic energy and Zeeman energy, and the field-induced antiferromagnetic to ferromagnetic phase transition at low temperatures is of first-order in nature.

This paper introduces a supercell model to explain the field-induced multiple transitions and the anomalous dilution effect in the nonmagnetic-substituting intermetallic compounds Dy 50− x Al x Ag 50 , in which the shift of the field-induced transitions in the Al-doped samples results from the change of the magnetic structure. At the doping level of x =1.8 (the ratio of Al/Dy approximates 1/26), an anomalous magnetic dilution effect was observed, in which the dilution effect becomes weak and the magnetic behavior is fairly similar to that of pure DyAg. We assumed that the anomalous dilution effect mainly results from the formation of uniform distribution of supercell in the doped Dy 48.2 Al 1.8 Ag 50 .

This study used three kinds of wax and three kinds of oil, with fixed mixture ratio including UV-blocking materials of ethylhexyl methoxycinnamate, oxybenzone, and avobenzone, and applied hot high-pressure homogenization process to prepare nanolipid sunscreen formulations. The measured particle size of the sunscreen formulations was 100~300 nm around PDI of 0.2 having a moderate polydisperse system. The distribution of zeta potential was −50 mV to −35 mV, showing a stable system. The UV light-absorbing range of 9 groups of sunscreen formulations was 275 nm~380 nm ranging within UVA and UVB. The rheological analysis found that the viscosity change is shear, thinning exhibiting colloid behavior. Taguchi analysis found that the optimum combinations are the carnauba wax and the blackcurrant oil combination for crystallinity and the beeswax and CPG oil for UV absorption. In addition, UV-blocking ability shows that the SPF was 51.5 and PFA was three stars for SU9 formulation. Finally, the effect of temperature on the properties of sunscreen formulations was also explored.

The enhanced 2D layered structure single crystalline TlCo2Se2 has been successfully fabricated, which exhibits field-induced 3D spin-flop phase transitions. In the case of the magnetic field parallel to the c-axis (B//c), the applied magnetic field induces the evolution of the noncollinear helical magnetic coupling into a ferromagnetic (FM) state with all the magnetization of the Co ion parallel to the c-axis. A striking variation of the field-induced strain within the ab-plane is noticed in the magnetic field region of 20-30 T. In the case of the magnetic field perpendicular to the c-axis (B ⊥ c), the inter-layer helical antiferromagnetic (AFM) coupling may transform to an initial canted AFM coupling, and then part of it transforms to an intermediate metamagnetic phase with the alignment of two-up-one-down Co magnetic moments and finally to an ultimate FM coupling in higher magnetic fields. The robust noncollinear AFM magnetic coupling is completely destroyed above 30 T. In combination with the measurements of magnetization, magnetoresistance and field-induced strain, a complete magnetic phase diagram of the TlCo2Se2 single crystal has been depicted, demonstrating complex magnetic structures even though the crystal geometry itself gives no indication of the magnetic frustration.

Measurements of the isothermal magnetization on La0.27Nd0.4Ca0.33MnO3 have been performed in a field up to 7 T at various temperatures. A distinct field-induced metamagnetic transition is observed within a temperature region of 2–180 K, resulting from the coexistence of charge ordered (CO), antiferromagnetic (AFM) and ferromagnetic (FM) phases. A temperature and magnetic field dependent irreversible CO–FM transition appears in the lower temperature region. Accompanying the transition an obvious lattice strain was observed, indicating that the transition is related to the change of lattice strain due to strong spin–lattice coupling in La0.27Nd0.4Ca0.33MnO3. These properties make the doped manganites a good candidate for a magnetostriction sensor material.

High-quality single-crystal Sr6Co5O15–δ (δ = 1.33) was successfully synthesized with a flux method. Detailed crystalline structure was determined by single-crystal X-ray diffraction at 298 K, which revealed a quasi-one-dimensional Co–O chain-like structure of this oxygen-deficient material. The magnetizations were measured in a pulsed high magnetic field up to 32 T and with a Physical Property Measurement System (PPMS). A large anisotropy and a distinct spin-flip transition were observed in the magnetization behavior. Theoretical calculation based on Botana's results suggests that interchain interaction (non-one-dimensional magnetic coupling) plays an important role in the magnetic properties of Sr6Co5O15–δ.

Through applied voltage (VAC), the characteristic of dye-doped liquid crystal random lasers (DDLC-RLs) inside capillary fiber (CF) has been readily and efficiently modulated. As VAC rose, the intensity of the emission spike increased dramatically at a fixed excited energy, and the slope efficiency of DDLC-RL increased obviously. By means of the white light scattering spectrum, the increase in the output from DDLC-RL is attributed to the enhancement of recurrent light scattering within the liquid crystals (LCs) to strengthen the light localization. In order to distinguish the characteristic of DDLC-RL with VAC = 0 V and 60 V, the α-stable distribution was adopted to show the Levy distribution of intensity fluctuation with a reduction in value from α = 1.86 to α = 1.59.

An innovative fabrication method to produce a macroporous Si surface by employing an anodic aluminium oxide (AAO) nanopore array layer as an etching template is presented. Combining AAO with a reactive ion etching (RIE) processes, a homogeneous and macroporous silicon surface can be effectively configured by modulating AAO process parameters and alumina film thickness, thus hopefully replacing conventional photolithography and electrochemical etch methods. The hybrid process integration is considered fully CMOS compatible thanks to the low-temperature AAO and CMOS processes. The gas-sensing characteristics of 50 nm TiO(2) nanofilms deposited on the macroporous surface are compared with those of conventional plain (or non-porous) nanofilms to verify reduced response noise and improved sensitivity as a result of their macroporosity. Our experimental results reveal that macroporous geometry of the TiO(2) chemoresistive gas sensor demonstrates 2-fold higher (∼33%) improved sensitivity than a non-porous sensor at different levels of oxygen exposure. In addition, the macroporous device exhibits excellent discrimination capability and significantly lessened response noise at 500 °C. Experimental results indicate that the hybrid process of such miniature and macroporous devices are compatible as well as applicable to integrated next generation bio-chemical sensors.

A class of nanoporous TiO2 gas sensors processed by novel anodic aluminum oxidation (AAO) of Al thin films and microelectromechnical systems (MEMS) techniques are presented. To enhance the sensitivity and reduce the sensing dimensions of a gas sensor, a nanoporous surface of the gas-sensitive material on the sensor is required. These sensors can be implemented on silicon or silicon dioxide substrate featuring a thin membrane of micro-hotplate structure featuring micro-heaters, thermometers and electrodes, and thus operate as chemoresistive devices. Combining the AAO method with dry-etch process, a homogeneous and nanoporous SiO2 surface of the sensor can be effectively configured by modulating various hole diameters and depth, hence replacing conventional photolithography and electrochemical etch. The process integration including AAO, reactive ion etch (RIE) and microfabrication is mainly developed and a feasibility study of PVD TiO2 thin film deposition upon the porous device is also provided. TiO2 thin films deposited on the nanoporous surface are investigated and compared with non-porous TiO2 films. It is encouraging that our fabrication process is able to provide relatively high surface area to enhance sensitivity of the sensor without additional doping steps. Our promising experimental results have revealed these miniature and cost-effective devices are not only compatible, but applicable to smart bio-chemical sensors of next generation.

This research studies the heat transfer characteristic of an unsteady close-contact melting on a flat plate in the cool-thermal discharge systems with external recycle, develops the mathematical model theoretically to simulate the conduction-convection heat-transfer phenomena, and calculates the theoretical prediction of the outlet chilled air temperature by solving the energy balance associated with integral boundary-layer analysis. It is found that the recycle effect can enhance the average Nusselt numbers and heat-transfer efficiency improvement effectively. Three numerical examples of inlet ambient air temperature are illustrated to compute the chilled air temperature, average Nusselt numbers and heat-transfer efficiency with three specified volumetric flow rate and three traversed length of the ambient inlet air as parameters.

Magnetization behavior of (La 0.83 Bi 0.17 ) 0.67 Ca 0.33 MnO 3 has been investigated in the temperature range from 100 to 180 K. A metamagnetic transition was observed in the temperature region, where the magnetization was measured after a zero-field-cooling from room temperature to a selected temperature. Experimental results show that, after a higher magnetization route, the field-increasing branches of the magnetization curves shows an unusual training effect: below a magnetic field H 0 , the applied magnetic field enhances the value of magnetization; however, above H 0 the magnetic field suppresses the value, and the behavior cannot be totally attributed to the enhancement effect of the applied magnetic field on ferromagnetic phase fraction. It is proposed that, in the two-phase coexistence region, the higher magnetic field promotes the phase separation and leads to both the fraction of ferromagnetic domain and the stabilization of antiferromagnetic domain increase.

Unidirectional carbon fibre cloth/carbon composite laminates were fabricated by hot-pressing alternating stacks of unidirectional carbon fibre cloth and uniformly-spread powder mixtures of phenolic-resin coated nature graphite flakes and pitch.The effects of the contents of carbon fibre cloth on the density,porosity,flexural strength,friction and wear properties of the composite laminates were investigated by SEM,a friction-and-wear testing machine and a universal testing machine.Results showed that the sample with the best overall performance had a mass fraction of carbon fibre cloth of 50%.This material had a flexural strength of 112.2 MPa,a density of 1.72 g/cm3,a friction coefficient of 0.28,and a wear rate of 3.68×10-13 m3 · N-1 · m-1.Failure behavior was pseudoplastic and there were a large number of fibre pullouts on the fracture surface.An increase of graphite content was favorable for the formation of a film during wear,which reduced the wear rate and resulted in a steady value of the coefficient of friction.