SAR(Specific Absorption Rate)通常称为吸收比值或吸收比率,是指移动终端电磁波能量吸收比值。目前国际通用的标准有两个,一个是欧洲标准(CE)每10克小于2.0w/kg,一个是美国标准(FCC)每克小于1.6mw/g。移动终端的SAR与TRP(Total Radio P...SAR(Specific Absorption Rate)通常称为吸收比值或吸收比率,是指移动终端电磁波能量吸收比值。目前国际通用的标准有两个,一个是欧洲标准(CE)每10克小于2.0w/kg,一个是美国标准(FCC)每克小于1.6mw/g。移动终端的SAR与TRP(Total Radio Power总辐射功率)这一相互制约的关系成了目前移动终端在保证高要求的发射功率条件下有低SAR值的难题。一般的降SAR方式为在主板上的热点处贴吸波材料,但是这有碍于终端的结构设计,并且成本较高,可靠性不佳。本论文通过天线本体设计来改变移动终端的主板上的电流分布,在保证总电流强度不减小的情况下通过降低主板上的电流峰值来降低SAR值。大大节省了降SAR成本。具有较高的推广性和可实现性。展开更多
The impact of the electromagnetic waves (EM) on human neurons (HN) has been under investigation for decades, in efforts to understand the impact of cell phones (radiation) on human health, or radiation absorption by H...The impact of the electromagnetic waves (EM) on human neurons (HN) has been under investigation for decades, in efforts to understand the impact of cell phones (radiation) on human health, or radiation absorption by HN for medical diagnosis and treatment. Research issues including the wave frequency, power intensity, reflections and scattering, and penetration depths are of important considerations to be incorporated into the research study. In this study, computer simulation for the EM exposure to HN was studied for the purpose of determining the upper limits of the electric and magnetic field intensities, power consumption, reflections and transmissions, and the change in temperature resulting from the power absorption by human neurons. Both high frequency structural simulators (HFSS) from ANSYS software, and COMSOL multi-physics were used for the simulation of the EM transmissions and reflections, and the temperature profile within the cells, respectively. For the temperature profile estimation, the study considers an electrical source of 0.5 watt input power, 64 MHz. The EM simulation was looking into the uniformity of the fields within the sample cells. The size of the waveguide was set to be appropriate for a small animal model to be conducted in the future. The incident power was fully transmitted throughout the waveguide, and less than 1% reflections were observed from the simulation. The minimum reflected power near the sample under investigation was found to be with negligible reflected field strengths. The temperature profile resulting from the COMSOL simulation was found to be near 0.25 m°K, indicating no change in temperature on the neuro cells under the EM exposure. The paper details the simulation results for the EM response determined by HFSS, and temperature profile simulated by COMSOL.展开更多
The hard - sphere three - parameter equation of state(CSPT) proposed in the previous paper(Li et al. 1991) was modified by a new temperature relation for the pseudo-critical compressibility ξc and the temperature cor...The hard - sphere three - parameter equation of state(CSPT) proposed in the previous paper(Li et al. 1991) was modified by a new temperature relation for the pseudo-critical compressibility ξc and the temperature correction factor α(Tr) of the attractive parameter. Vapor pressures and saturated liquid densities of 105 pure compounds were calculated by the modified version. Results show that correlations of saturated properties at low reduced temperatures and thermodynamic properties in the vicinity of critical region were significantly improved. Furthermore, characteristic parameters of this modified version were generalized by acentric factor ω and critical compressibility Zc to predict saturated liquid densities of 72 polar substances and the latent heat of vaporization for 151 substances including strongly polar compounds with satisfactory results.展开更多
Britholite-Y is milkwhite, rosy in colour. The measured specific gravity is 4.35, with Ng′ = 1.791, Np′ = 1.784. As determined by electron microprobe, its crystal formula is (Y2.82Ca1.58Ce0.27Dy0.21Er0.11)5 [(Si2.95...Britholite-Y is milkwhite, rosy in colour. The measured specific gravity is 4.35, with Ng′ = 1.791, Np′ = 1.784. As determined by electron microprobe, its crystal formula is (Y2.82Ca1.58Ce0.27Dy0.21Er0.11)5 [(Si2.95P0.05)3O12](OH,F), space group = C22-P21, a = (0.9504±0.0005) nm, b = (0.9414±0.0004) nm, c = (0.6922±0.0002) nm, r = (119.71±0.04)°, V = (53.79±0.04) nm3, Z = 2. Least-squares refinements with 2272 independent reflection (F0>3σ|F0|) yielded R = 0.111. The change of symmetry group P63/m of apatite to P21 of britholite-Y results from the shifts of Y, Ca, Si, O and (OH) atoms (anions) from the pseudohexagonal P63/m equivalent positions (6h), (4f), (12i) and (2a) as produced by distortion of the polyhedra with 7-, 9-, and 4-corners. The substitution of Ca in apatite for Y and the order distribution of atoms Y and Ca on the equivalent positions (6h) and (4f) have contributed to the distortion of 7- and 9- cornered polyhedra. The substitutions of Si4+ for P5+ and OH- for F- may also be effected. The crystal chemistry of apatite-group minerals is also discussed.展开更多
The influence of atomic densities on the propagation property for ultrashort pulses in a two-level atom (TLA) medium is investigated. With higher atomic densities, the self-induced transparency (SIT) cannot be recover...The influence of atomic densities on the propagation property for ultrashort pulses in a two-level atom (TLA) medium is investigated. With higher atomic densities, the self-induced transparency (SIT) cannot be recovered even for 2πultrashort pulses. New features such as pulse splitting, red-shift and blue-shift of the corresponding spectra arise, and the component of central frequency gradually disappears.展开更多
文摘SAR(Specific Absorption Rate)通常称为吸收比值或吸收比率,是指移动终端电磁波能量吸收比值。目前国际通用的标准有两个,一个是欧洲标准(CE)每10克小于2.0w/kg,一个是美国标准(FCC)每克小于1.6mw/g。移动终端的SAR与TRP(Total Radio Power总辐射功率)这一相互制约的关系成了目前移动终端在保证高要求的发射功率条件下有低SAR值的难题。一般的降SAR方式为在主板上的热点处贴吸波材料,但是这有碍于终端的结构设计,并且成本较高,可靠性不佳。本论文通过天线本体设计来改变移动终端的主板上的电流分布,在保证总电流强度不减小的情况下通过降低主板上的电流峰值来降低SAR值。大大节省了降SAR成本。具有较高的推广性和可实现性。
文摘The impact of the electromagnetic waves (EM) on human neurons (HN) has been under investigation for decades, in efforts to understand the impact of cell phones (radiation) on human health, or radiation absorption by HN for medical diagnosis and treatment. Research issues including the wave frequency, power intensity, reflections and scattering, and penetration depths are of important considerations to be incorporated into the research study. In this study, computer simulation for the EM exposure to HN was studied for the purpose of determining the upper limits of the electric and magnetic field intensities, power consumption, reflections and transmissions, and the change in temperature resulting from the power absorption by human neurons. Both high frequency structural simulators (HFSS) from ANSYS software, and COMSOL multi-physics were used for the simulation of the EM transmissions and reflections, and the temperature profile within the cells, respectively. For the temperature profile estimation, the study considers an electrical source of 0.5 watt input power, 64 MHz. The EM simulation was looking into the uniformity of the fields within the sample cells. The size of the waveguide was set to be appropriate for a small animal model to be conducted in the future. The incident power was fully transmitted throughout the waveguide, and less than 1% reflections were observed from the simulation. The minimum reflected power near the sample under investigation was found to be with negligible reflected field strengths. The temperature profile resulting from the COMSOL simulation was found to be near 0.25 m°K, indicating no change in temperature on the neuro cells under the EM exposure. The paper details the simulation results for the EM response determined by HFSS, and temperature profile simulated by COMSOL.
基金Supported by the National Natural Science Foundation of China
文摘The hard - sphere three - parameter equation of state(CSPT) proposed in the previous paper(Li et al. 1991) was modified by a new temperature relation for the pseudo-critical compressibility ξc and the temperature correction factor α(Tr) of the attractive parameter. Vapor pressures and saturated liquid densities of 105 pure compounds were calculated by the modified version. Results show that correlations of saturated properties at low reduced temperatures and thermodynamic properties in the vicinity of critical region were significantly improved. Furthermore, characteristic parameters of this modified version were generalized by acentric factor ω and critical compressibility Zc to predict saturated liquid densities of 72 polar substances and the latent heat of vaporization for 151 substances including strongly polar compounds with satisfactory results.
文摘Britholite-Y is milkwhite, rosy in colour. The measured specific gravity is 4.35, with Ng′ = 1.791, Np′ = 1.784. As determined by electron microprobe, its crystal formula is (Y2.82Ca1.58Ce0.27Dy0.21Er0.11)5 [(Si2.95P0.05)3O12](OH,F), space group = C22-P21, a = (0.9504±0.0005) nm, b = (0.9414±0.0004) nm, c = (0.6922±0.0002) nm, r = (119.71±0.04)°, V = (53.79±0.04) nm3, Z = 2. Least-squares refinements with 2272 independent reflection (F0>3σ|F0|) yielded R = 0.111. The change of symmetry group P63/m of apatite to P21 of britholite-Y results from the shifts of Y, Ca, Si, O and (OH) atoms (anions) from the pseudohexagonal P63/m equivalent positions (6h), (4f), (12i) and (2a) as produced by distortion of the polyhedra with 7-, 9-, and 4-corners. The substitution of Ca in apatite for Y and the order distribution of atoms Y and Ca on the equivalent positions (6h) and (4f) have contributed to the distortion of 7- and 9- cornered polyhedra. The substitutions of Si4+ for P5+ and OH- for F- may also be effected. The crystal chemistry of apatite-group minerals is also discussed.
基金The work was supported by the National Natural Science Foundation of China (No. 60478002) and the Natural Science Key Foundation of Shanghai (No. 04JC14036).
文摘The influence of atomic densities on the propagation property for ultrashort pulses in a two-level atom (TLA) medium is investigated. With higher atomic densities, the self-induced transparency (SIT) cannot be recovered even for 2πultrashort pulses. New features such as pulse splitting, red-shift and blue-shift of the corresponding spectra arise, and the component of central frequency gradually disappears.
