The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount...The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g,, it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84--24 mg/m^3 by O3/TiO2flJV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m^3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/（m^3.min） and Langmuir adsorption coefficient K of 0.0268 m^3/mg were obtained.展开更多
A new copper（Ⅱ） compound with imino nitroxide radicals [Cu（IM-MeImz）2].（SCN）2 （IM-meImz =2-（5-methylimidazol-4-yl）-4,4,5,5-tetramethyl-2-imidazoline- 1-oxyl） has been synthesized and characterized structura...A new copper（Ⅱ） compound with imino nitroxide radicals [Cu（IM-MeImz）2].（SCN）2 （IM-meImz =2-（5-methylimidazol-4-yl）-4,4,5,5-tetramethyl-2-imidazoline- 1-oxyl） has been synthesized and characterized structurally and magnetically. It crystallizes in monoclinic, space group P21/c with a = 9.3604（7）, b = 10.3012（7）, c = 16.6684（12）A, β = 105.0290（10）^o, V = 1552.25（19）A3, C24H34CUN10O2S2, Mr = 622.27, Z = 2, Dc = 1.331 g/cm^3,μ（MoKα） = 0.876 mm^-1, F（000） = 650, the final R = 0.0374 and wR = 0.1079. X-ray analysis demonstrates that the IM-MeImz ligand is coordinated to the copper（Ⅱ） ion as an unusual didentate chelate with a k-2 N（MeImz）,O（IM） mode in the complex. The square-planar coordination sites at Cu（Ⅱ） are occupied by two 0 and two N atoms from the imino nitroxide radicals. The complex molecules are connected as a onedimensional polymer structure by intermolecular interactions. Magnetic measurements show that there are intramolecular antiferromagnetic interactions between the Cu（Ⅱ） ion and radicals.展开更多
We consider a triple zero point of nonlinear equations with O(2 symmetry, where the Jacobian has a zero eigenvalue of geometric multiplicity one and algebraic multiplicity three. We show that this triple zero point e...We consider a triple zero point of nonlinear equations with O(2 symmetry, where the Jacobian has a zero eigenvalue of geometric multiplicity one and algebraic multiplicity three. We show that this triple zero point exhibits a new bifurcation phenomenon, that is, a mode interaction of the following three paths: bifurcation points from steady states, steady states and rotating waves to standing waves, rotating waves and modulated rotating waves respectively.展开更多
A new electron cyclotron resonance launcher system has been designed and installed on heating and current drive （ECRH/ECCD） the HL-2A tokamak to inject four beams and enable continuous millimeter-wave beam scanning ...A new electron cyclotron resonance launcher system has been designed and installed on heating and current drive （ECRH/ECCD） the HL-2A tokamak to inject four beams and enable continuous millimeter-wave beam scanning independently in the toroidal and poloidal direc- tions for ECRH/ECCD experiments. The launcher is connected to four mm-wave lines capable of transmitting high power up to 3 MW with two 1 MW/140 GHz/3 s and two 0.5 MW/68 GHz/1 s beams. Based on ray tracing simulation using the TORAY-GA code, tile scanning range of wave beams is -15~~15~ in the toroidal direction and 0~~10~ in the poloidal one for 140 GHz beams, which could cover half of the cross section of plasmas and can satisfy the requirements of advanced physical experiments. The beam radii in the plasma is 17.1 mm and 20 mm for the two 140 GHz beams and 29.5 nnn for the two 68 GHz beams, respectively, allowing a very high localization of the absorbed power. The performance of the steering system was proven to be reliable and the linearity is perfect between the displacement of drive shaft and rotate angle of mirror. Addition- ally the injection performance of the wave beams was optinfized by simultaneously setting the injection angle and the polarization to realize desirable pure O- or X-mode injection.展开更多
The modification of A356 aluminum-silicon alloy using yttrium oxide (Y2O3) was studied. Addition levels of up to 2.5 wt.% Y2O3 were investigated. A premixed powder of Al-30wt.%Y2O3 was added to the melt at about 750℃...The modification of A356 aluminum-silicon alloy using yttrium oxide (Y2O3) was studied. Addition levels of up to 2.5 wt.% Y2O3 were investigated. A premixed powder of Al-30wt.%Y2O3 was added to the melt at about 750℃ using vortex method. Samples were then poured in sand mold. The results showed that evident modification was obtained using the Y2O3 addition. The optimum level was 1.5 wt.%, and was corresponding to a eutectic temperature depression from 568 to 557℃. The eutectic Si particles were refined in length from 44.8 to 8.3 μm, and modified in aspect ratio from 6.8 to 0.98. Higher additions of Y2O3 caused de-modification of the eutectic Si particles. The ductility of the modified specimens was enhanced by more than 20% compared to the unmodified ones. This was associated with a gradual transfer from cleavage to a more ductile mode of fracture.展开更多
A temperature-dependent Raman spectroscopic study on Bi2 Zn OB2O6crystal was carried out to investigate the structure change of the crystal with the increase of temperature. Raman spectra of crystal Bi2 Zn OB2O6were r...A temperature-dependent Raman spectroscopic study on Bi2 Zn OB2O6crystal was carried out to investigate the structure change of the crystal with the increase of temperature. Raman spectra of crystal Bi2 Zn OB2O6were recorded in the spectral range 10–1600 cm-1at room temperature first. Compared with the vibrational spectra of the referred compounds,satisfactory assignment of most of the high-energy modes to vibrations of Bi–O, B–O, and Zn–O bonds was achieved. In particular, the Raman high-frequency peak located at 1344 cm-1was attributed to the B–O vibration in the BO3 triangle.This temperature-dependent Raman spectroscopic study was carried out up to 600°C. It was found that all the Raman lines exhibit decreases in frequency and the widths of the Raman peaks increase with increasing temperature. No phase transition was observed under 600°C.展开更多
With the progress of ULSI technology, materials with low dielectric constant are required to replace SiO2 film as the interlayer to scale down the interconnection delay. Fluorinated Si oxide thin films (SiOF) are a pr...With the progress of ULSI technology, materials with low dielectric constant are required to replace SiO2 film as the interlayer to scale down the interconnection delay. Fluorinated Si oxide thin films (SiOF) are a promising material for the low dielectric constant and the process compatibility in existing technology. However, SiOF films are liable to absorb moisture when exposed to air. By treating the SiOF films with O-2 plasma, it was found that the moisture resistibility of SiOF films was remarkably improved. The mechanism of the improvement in stability of dielectric constant was investigated. The results show that: 1) F atoms dissociated from the films and the bond angle of Si-O-Si decreased. 2) The plasma treatment enhanced the strength of Si-F bonds by removing unstable =SiF2 structures in the films. Resistibility of SiOF films in moisture was improved.展开更多
Although In2O3 nanofibers （NFs） are well-known candidates as active materials for next-generation, low-cost electronics, these NF based devices still suffer from high leakage current, insufficient on-off current rat...Although In2O3 nanofibers （NFs） are well-known candidates as active materials for next-generation, low-cost electronics, these NF based devices still suffer from high leakage current, insufficient on-off current ratios （Ion/Ioff）, and large, negative threshold voltages （VTH）, leading to poor device performance, parasitic energy consumption, and rather complicated circuit design. Here, instead of the conventional surface modification of In2O3 NFs, we present a one-step electrospinning process （i.e., without hot-press） to obtain controllable Mg-doped In2O3 NF networks to achieve high-performance enhancement-mode thin-film transistors （TFTs）. By simply adjusting the Mg doping concentration, the device performance can be manipulated precisely. For the optimal doping concentration of 2 mol%, the devices exhibit a small VTH （3.2 V）, high saturation current （1.1 × 10^-4 A）, large on/off current ratio （〉 10^8）, and respectable peak carrier mobility （2.04 cm2/（V.s））, corresponding to one of the best device performances among all 1D metal-oxide NFs based devices reported so far. When high-K HfOx thin films are employed as the gate dielectric, their electron mobility and VTH can be further improved to 5.30 cm^2/（V.s） and 0.9 V, respectivel）, which demonstrates the promising prospect of these Mg-doped In2O3 NF networks for high- performance, large-scale, and low-power electronics.展开更多
We used a ultrasound/Fe2＋/H2O2 process in continuous dosing mode to degrade the alachlor. Experimental results indicated that lower pH levels enhanced the degradation and mineralization of alachlor. The maximum alach...We used a ultrasound/Fe2＋/H2O2 process in continuous dosing mode to degrade the alachlor. Experimental results indicated that lower pH levels enhanced the degradation and mineralization of alachlor. The maximum alachlor degradation （initial alachlor concentration of 50 mg/L） was as high as 100% at pH 3 with ultrasound of 100 Watts, 20 mg/L of Fe2＋, 2 mg/min of H2O2 and 20℃ within 60 min reaction combined with 46.8% total organic carbon removal. Higher reaction temperatures inhibited the degradation of alachlor. Adequate dosages of Fe2＋ and H2O2 in ultrasound/Fe2＋/H2O2 process not only enhance the degradation efficiency of alachlor but also save the operational cost than the sole ultrasound or Fenton process. A continuous dosing mode ultrasound/Fe2＋/H2O2 process was proven as an effective method to degrade the alachlor.展开更多
基金Project supported by the Science Project of Harbin City(No. H2001-12)the Youth Foundation of School of Municipal and Environmental Engineering in Harbin Institute of Technology(No. 01306914).
文摘The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g,, it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84--24 mg/m^3 by O3/TiO2flJV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m^3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/（m^3.min） and Langmuir adsorption coefficient K of 0.0268 m^3/mg were obtained.
基金This work was supported by the N N S F of China (No. 20471026)the Natural Science Foundation of Henan Province (No. 0311021200)
文摘A new copper（Ⅱ） compound with imino nitroxide radicals [Cu（IM-MeImz）2].（SCN）2 （IM-meImz =2-（5-methylimidazol-4-yl）-4,4,5,5-tetramethyl-2-imidazoline- 1-oxyl） has been synthesized and characterized structurally and magnetically. It crystallizes in monoclinic, space group P21/c with a = 9.3604（7）, b = 10.3012（7）, c = 16.6684（12）A, β = 105.0290（10）^o, V = 1552.25（19）A3, C24H34CUN10O2S2, Mr = 622.27, Z = 2, Dc = 1.331 g/cm^3,μ（MoKα） = 0.876 mm^-1, F（000） = 650, the final R = 0.0374 and wR = 0.1079. X-ray analysis demonstrates that the IM-MeImz ligand is coordinated to the copper（Ⅱ） ion as an unusual didentate chelate with a k-2 N（MeImz）,O（IM） mode in the complex. The square-planar coordination sites at Cu（Ⅱ） are occupied by two 0 and two N atoms from the imino nitroxide radicals. The complex molecules are connected as a onedimensional polymer structure by intermolecular interactions. Magnetic measurements show that there are intramolecular antiferromagnetic interactions between the Cu（Ⅱ） ion and radicals.
文摘We consider a triple zero point of nonlinear equations with O(2 symmetry, where the Jacobian has a zero eigenvalue of geometric multiplicity one and algebraic multiplicity three. We show that this triple zero point exhibits a new bifurcation phenomenon, that is, a mode interaction of the following three paths: bifurcation points from steady states, steady states and rotating waves to standing waves, rotating waves and modulated rotating waves respectively.
基金supported by National Magnetic Confinement Thermonuclear Fusion Energy Research Project(No.2009GB102004)Cooperation on Key Technology of Plasma Heating in Tokamak(No.2010DFA63860)+1 种基金National Natural Science Foundation of China(No.11175059)Critical Technology Research of Nuclear Fusion and Physical Experiments and on HL-2A Tokamak(No.H660003)
文摘A new electron cyclotron resonance launcher system has been designed and installed on heating and current drive （ECRH/ECCD） the HL-2A tokamak to inject four beams and enable continuous millimeter-wave beam scanning independently in the toroidal and poloidal direc- tions for ECRH/ECCD experiments. The launcher is connected to four mm-wave lines capable of transmitting high power up to 3 MW with two 1 MW/140 GHz/3 s and two 0.5 MW/68 GHz/1 s beams. Based on ray tracing simulation using the TORAY-GA code, tile scanning range of wave beams is -15~~15~ in the toroidal direction and 0~~10~ in the poloidal one for 140 GHz beams, which could cover half of the cross section of plasmas and can satisfy the requirements of advanced physical experiments. The beam radii in the plasma is 17.1 mm and 20 mm for the two 140 GHz beams and 29.5 nnn for the two 68 GHz beams, respectively, allowing a very high localization of the absorbed power. The performance of the steering system was proven to be reliable and the linearity is perfect between the displacement of drive shaft and rotate angle of mirror. Addition- ally the injection performance of the wave beams was optinfized by simultaneously setting the injection angle and the polarization to realize desirable pure O- or X-mode injection.
基金financial support from the Central Metallurgical Research and Development Institute (CMRDI), Ministry of Scientific Research, Egypt
文摘The modification of A356 aluminum-silicon alloy using yttrium oxide (Y2O3) was studied. Addition levels of up to 2.5 wt.% Y2O3 were investigated. A premixed powder of Al-30wt.%Y2O3 was added to the melt at about 750℃ using vortex method. Samples were then poured in sand mold. The results showed that evident modification was obtained using the Y2O3 addition. The optimum level was 1.5 wt.%, and was corresponding to a eutectic temperature depression from 568 to 557℃. The eutectic Si particles were refined in length from 44.8 to 8.3 μm, and modified in aspect ratio from 6.8 to 0.98. Higher additions of Y2O3 caused de-modification of the eutectic Si particles. The ductility of the modified specimens was enhanced by more than 20% compared to the unmodified ones. This was associated with a gradual transfer from cleavage to a more ductile mode of fracture.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.50932005 and 51102239)
文摘A temperature-dependent Raman spectroscopic study on Bi2 Zn OB2O6crystal was carried out to investigate the structure change of the crystal with the increase of temperature. Raman spectra of crystal Bi2 Zn OB2O6were recorded in the spectral range 10–1600 cm-1at room temperature first. Compared with the vibrational spectra of the referred compounds,satisfactory assignment of most of the high-energy modes to vibrations of Bi–O, B–O, and Zn–O bonds was achieved. In particular, the Raman high-frequency peak located at 1344 cm-1was attributed to the B–O vibration in the BO3 triangle.This temperature-dependent Raman spectroscopic study was carried out up to 600°C. It was found that all the Raman lines exhibit decreases in frequency and the widths of the Raman peaks increase with increasing temperature. No phase transition was observed under 600°C.
基金The work was supported by the National Natural Science Foundation of China(No.69776026)the Foundation for University Key Teacher by the Ministry of Education.
文摘With the progress of ULSI technology, materials with low dielectric constant are required to replace SiO2 film as the interlayer to scale down the interconnection delay. Fluorinated Si oxide thin films (SiOF) are a promising material for the low dielectric constant and the process compatibility in existing technology. However, SiOF films are liable to absorb moisture when exposed to air. By treating the SiOF films with O-2 plasma, it was found that the moisture resistibility of SiOF films was remarkably improved. The mechanism of the improvement in stability of dielectric constant was investigated. The results show that: 1) F atoms dissociated from the films and the bond angle of Si-O-Si decreased. 2) The plasma treatment enhanced the strength of Si-F bonds by removing unstable =SiF2 structures in the films. Resistibility of SiOF films in moisture was improved.
基金The work was financially supported by the National Natural Science Foundation of China （Nos. 51402160, 51302154, and 51672229）, the General Research Fund of the Research Grants Council of Hong Kong, China （No. CityU 11275916）, the Natural Science Foundation of Shandong Province, China （No. ZR2014EMQ011）, the Taishan Scholar Program of Shandong Province, China, the Science Technology, and Innovation Committee of Shenzhen Municipality （No. JCYJ20160229165240684）, and was supported by a grant from the Shenzhen Research Institute, City University of Hong Kong. The work was also supported by National Demonstration Center for Experimental Applied Physics Education （Qingdao University）.
文摘Although In2O3 nanofibers （NFs） are well-known candidates as active materials for next-generation, low-cost electronics, these NF based devices still suffer from high leakage current, insufficient on-off current ratios （Ion/Ioff）, and large, negative threshold voltages （VTH）, leading to poor device performance, parasitic energy consumption, and rather complicated circuit design. Here, instead of the conventional surface modification of In2O3 NFs, we present a one-step electrospinning process （i.e., without hot-press） to obtain controllable Mg-doped In2O3 NF networks to achieve high-performance enhancement-mode thin-film transistors （TFTs）. By simply adjusting the Mg doping concentration, the device performance can be manipulated precisely. For the optimal doping concentration of 2 mol%, the devices exhibit a small VTH （3.2 V）, high saturation current （1.1 × 10^-4 A）, large on/off current ratio （〉 10^8）, and respectable peak carrier mobility （2.04 cm2/（V.s））, corresponding to one of the best device performances among all 1D metal-oxide NFs based devices reported so far. When high-K HfOx thin films are employed as the gate dielectric, their electron mobility and VTH can be further improved to 5.30 cm^2/（V.s） and 0.9 V, respectivel）, which demonstrates the promising prospect of these Mg-doped In2O3 NF networks for high- performance, large-scale, and low-power electronics.
基金supported by the National Science Council, Republic of China (No. 101-2221-E-264-005)
文摘We used a ultrasound/Fe2＋/H2O2 process in continuous dosing mode to degrade the alachlor. Experimental results indicated that lower pH levels enhanced the degradation and mineralization of alachlor. The maximum alachlor degradation （initial alachlor concentration of 50 mg/L） was as high as 100% at pH 3 with ultrasound of 100 Watts, 20 mg/L of Fe2＋, 2 mg/min of H2O2 and 20℃ within 60 min reaction combined with 46.8% total organic carbon removal. Higher reaction temperatures inhibited the degradation of alachlor. Adequate dosages of Fe2＋ and H2O2 in ultrasound/Fe2＋/H2O2 process not only enhance the degradation efficiency of alachlor but also save the operational cost than the sole ultrasound or Fenton process. A continuous dosing mode ultrasound/Fe2＋/H2O2 process was proven as an effective method to degrade the alachlor.
