白色iPhone4在中美等28国上市

千呼万唤始出来的白色版iPhone 4终于跟用户见面了,一再延迟上市时间的iPhone 4白色版已在中国、英国、美国等28个国家和地区上市. 这28个国家和地区分别为奥地利、澳大利亚、比利时、加拿大、中国、捷克共和国、丹麦、芬兰、法国、德国、中国香港、爱尔兰、意大利、日本、卢森堡、中国澳门、荷兰、新西兰、挪威、新加坡、韩国、西班牙、瑞士、瑞典、中国台湾、泰国、英国和美国.     

3D电视试验频道已在全国26省区市开通

截至2012年2月8日,《中国3D电视试验频道》开通地区分别为:吉林、山东、青海、宁夏、内蒙古、江苏、湖南、浙江、广东、广西、新疆、河北、陕西等22省、自治区的部分城市,以及北京、天津、上海、重庆、合肥、六安、厦门、武汉、太原、运城、铁岭     

本刊来稿须知

1．本刊设有专题论坛、专业改革、教学改革、科研报告、通讯动态、电子信息、电子科学、电气工程、自动控制、科技应用、课程改革、教学研究、教材建设、实践教学、教学方法、研究生教学、毕业设计、机辅教学、争鸣论坛、高职教育、教学仪器及电坛人物等栏目。     

第27届华东电视技术年会暨第8届华协体发展峰会圆满召开

2014年6月11日-14日，华东电视行业的年度盛会--第27届华东电视技术年会暨第8届华协体发展峰会在上海隆重召开。来自上海、浙江、江西、江苏、安徽、山东、福建、杭州、济南、厦门、青岛、宁波、南京等13家电视台，索尼、松下、索贝、大洋、新奥特、哈里斯、安恒利、安达斯、文广科技、STR、北京星光、捷成世纪、华创、风格等14家厂商的代表参加了本次年会。     

中国高等学校电子教育学会第26届学术年会会议纪要

中国高等学校电子教育学会第26届学术年会,于2011年8月5日至8日在贵州安顺学院召开。参加会议的有：湖南科技大学、延安大学、中南民族大学、西华大学、青海师范大学、温州大学、广东外语外贸大学、遵义师范学院、楚雄师范学院、咸阳师范学院、长江师范学院、陇东学院、河北北方学院、邢台学院、韶关学院、湖南人文科技学院、宿州学院、     

CMMB网络覆盖工程在全国范围内展开

随着北京奥运会的日益临近,我国移动多媒体广播项目CMMB网络覆盖工程正在全国各主要城市紧锣密鼓地展开。截至到4月30日,CMMB已经完成北京、上海、天津、沈阳、青岛、秦皇岛等六个奥运城市和广州、深圳、西安、成都、重庆、长沙、合肥、大连、厦门、福州、昆明、南京等城市的     

第22届华东电视技术年会暨第3届华协体发展峰会成功召开

2009年6月8—10日，第二十二届华东电视技术年会暨第三届华协体发展峰会在上海大宁福朋喜来登大酒店隆重召开。来自上海、厦门、江苏、江西、安徽、山东、浙江、福建、济南、青岛、宁波、南京、杭州13家电视台，索尼、松下、新奥特、大洋、索贝、哈里斯、安达斯、安恒利、文广科技、STR，捷成世纪、北京星光12家厂商的代表参加了年会。     

第24届华东电视技术年会暨第5届华协体发展峰会圆满召开

2011年6月6—10日,华东电视行业的年度盛会——“第二十四届华东电视技术年会暨第五届华协体发展峰会”在上海大宁福朋喜来登大酒店隆重召开。来自上海、浙江、江西、江苏、安徽、山东、福建、济南、厦门、青岛、宁波、南京、杭州等13家电视台,索尼、松下、索贝、大洋、新奥特、安达斯、安恒利、文广科技、STR、哈里斯、捷成世纪、...     

第二十四届华东电视技术年会暨第五届华协体发展峰会在沪隆重召开

2011年6月6～10日,华东电视行业的年度盛会——＂第二十四届华东电视技术年会暨第五届华协体发展峰会＂在上海大宁福朋喜来登大酒店隆重召开。来自上海、浙江、江西、江苏、安徽、山东、福建、济南、厦门、青岛、宁波、南京、杭州等13家电视台,索尼、松下、索贝、大洋、新奥特、安达斯、安恒利、文广科技、STR、哈里斯、捷成世纪、...     

7大板块夺目软交会

移动OA、监控、家居娱乐、智能医疗、导航与智能车载、云平台上的个人/商务应用、物联网案例,成为本届软交会展览区的最醒目内容。在本届软交会的展览区,英特尔、微软、SAP、IBM、思科、简柏特、甲骨文、HP、花旗数据、NEC、川崎重工、松下、SONY、亚美亚等著名跨国企业汇聚在"IT跨国公司长廊",英特尔和微软展区以导航、医疗、娱乐等各类互动式业务吸引了大批参展者。     

Planar p-on-n HgCdTe FPAs by Arsenic Ion Implantation

This paper reviews recent developments in the characterization of planar p-on-n photodiodes fabricated from long- and mid-wavelength Hg_1−x Cd _x Te at␣the Electronics and Information Technology Laboratory (LETI). The Hg_1−x Cd _x Te epitaxial layers were grown by both liquid-phase and molecular-beam epitaxy. Planar p-on-n photodiodes were fabricated by arsenic implantation into an indium-doped Hg_1−x Cd _x Te base layer. Electro-optical characterization on these p-on-n photodiodes showed low leakage currents (shunt resistance > 10 GΩ) and mean R ₀ A values comparable to the state of the art, i.e., equal to 5000 Ω cm² at λ _c = 9.3 μm (λ _c: cutoff wavelength). Results of focal-plane arrays operating in both the long-wavelength infrared (IR) and middle-wavelength IR bands are reported, with noise equivalent delta temperature and responsivity values at λ _c = 9.3 μm in excess of 99.64%. These results demonstrate the viability and technological maturity of both material growth and device processing.     

Temperature and frequency dependent electrical and dielectric properties of Al/SiO2/p-Si (MOS) structure

The electrical and dielectric properties of Al/SiO₂/p-Si (MOS) structures were studied in the frequency range 10 kHz-10 MHz and in the temperature range 295-400 K. The interfacial oxide layer thickness of 320 Å between metal and semiconductor was calculated from the measurement of the oxide capacitance in the strong accumulation region. The frequency and temperature dependence of dielectric constant (ε′), dielectric loss (ε″), dielectric loss tangent (tan δ) and the ac electrical conductivity (σ_ac) are studied for Al/SiO₂/p-Si (MOS) structure. The electrical and dielectric properties of MOS structure were calculated from C-V and G-V measurements. Experimental results show that the ε′ and ε″ are found to decrease with increasing frequency while σ_ac is increased, and ε′, ε″, tan δ and σ_ac increase with increasing temperature. The values of ε′, ε″ and tan δ at 100 kHz were found to be 2.76, 0.17 and 0.06, respectively. The interfacial polarization can be more easily occurred at low frequencies, and the number of interface state density between Si/SiO₂ interface, consequently, contributes to the improvement of dielectric properties of Al/SiO₂/p-Si (MOS) structure. Also, the effects of interface state density (N_ss) and series resistance (R_s) of the sample on C-V characteristics are investigated. It was found that both capacitance C and conductance G were quite sensitive to temperature and frequency at relatively high temperatures and low frequencies, and the N_ss and R_s decreased with increasing temperature. This is behavior attributed to the thermal restructuring and reordering of the interface. The C-V and G/ω-V characteristics confirmed that the N_ss, R_s and thickness of insulator layer (δ) are important parameters that strongly influence both the electrical and dielectric parameters and conductivity in MOS structures.     

Charge trapping and interface characteristics in normally-off Al2O3/GaN-MOSFETs

Normally-off GaN-MOSFETs with Al₂O₃ gate dielectric have been fabricated and characterized. The Al₂O₃ layer is deposited by ALD and annealed under various temperatures. The saturation drain current of 330 mA/mm and the maximum transconductance of 32 mS/mm in the saturation region are not significantly modified after annealing. The subthreshold slope and the low-field mobility value are improved from 642 to 347 mV/dec and from 50 to 55 cm² V⁻¹ s⁻¹, respectively. The I_D-V_G curve shows hysteresis due to oxide trapped charge in the Al₂O₃ before annealing. The amount of hysteresis reduces with the increase of annealing temperature up to 750 °C. The Al₂O₃ layer starts to crystallize at a temperature of 850 °C and its insulating property deteriorates.     

Dithienopyrrole-benzodithiophene based donor materials for small molecular BHJSCs: Impact of side chain and annealing treatment on their photovoltaic properties

Two small molecular organic materials denoted as ICT1 and ICT2 with A-D₁-D₂-D₁-A architecture have been synthesized and their thermal, photo-physical, electrochemical and photovoltaic properties are explored. Synthesized materials have n-butylrhodanine acceptor (A), dithienopyrrole (DTP) (D₁) and benzodithiophene (BDT) (D₂) (Alkoxy BDT and alkylthiophene BDT, respectively for ICT1 and ICT2) donor moieties. Both the materials have good solubility (up to 25 mg/mL) in most common organic solvents and have excellent thermal stability with the decomposition temperature (T_d) as 348 and 382 °C, respectively for ICT1 and ICT2. Both ICT1 and ICT2 have broad and intense visible region absorption (molar excitation coefficient is 1.71 × 10⁵ and 1.65 × 10⁵ mol⁻¹ cm⁻¹, respectively for ICT1 and ICT2) and have suitable HOMO and LUMO energy levels for PC₇₁BM acceptor. Bulk heterojunction solar cells with ITO/PEDOT:PSS/blend/Al structure are fabricated using these materials. The BHJSCs fabricated by spin cast of ICT1:PC₇₁BM and ICT2:PC₇₁BM (1:2 wt ratio) blend from chloroform showed power conversion efficiency (PCE) of 2.77% (J_sc = 6.84 mA/cm², V_oc = 0.92 V and FF = 0.44) and 3.27% (J_sc = 7.26 mA/cm², V_oc = 0.96 V and FF = 0.47), respectively. Annealing the active layer significantly improved the PCE of these BHJSCs to 5.12% (J_sc = 10.15 mA/cm², V_oc = 0.87 V and FF = 0.58) and 5.90% (J_sc = 10.68 mA/cm², V_oc = 0.92 V and FF = 0.60), respectively for ICT1 and ICT2 donors. The enhancement in the PCE is due to higher light harvesting ability of the active layer, better nanoscale morphology for efficient and balanced charge transport and effective exciton dissociation at the donor-acceptor interface.     

Microstructure of reactively sputtered oxide diffusion barriers

Molybdenum oxide (Mo_1-x O _x ) and ruthenium oxide (RuO₂) films were prepared by rf reactive sputtering of Mo or Ru targets in an O₂/Ar plasma. Both films exhibit metallic conductivities. The influence of the deposition parameters on the phase that forms and on the microstructure of Mo_1-x O _x and RuO₂ films is reported. A phase transformation is observed in Mo_1-x O _x films subjected to heat treatment. The diffusion barrier performance of Mo_1-x O _x and RuO₂ layers interposed between Al and Si is compared.     

Refractory metal boride ohmic contacts to P-type 6H-SiC

Ohmic contacts have been fabricated on p-type 6H-SiC (1.3×10¹⁹ cm⁻³) using CrB₂, W₂B, and TiB₂. The boride layers (∼100–200 nm) were sputter-deposited in a system with a base pressure of 3×10⁻⁷ Torr. Specific contact resistances were measured using the linear transmission line method, and the physical properties of the contacts were examined using Rutherford backscattering spectrometry. All as-deposited contacts exhibited rectifying characteristics. Ohmic behavior was observed following short anneals (2–10 min) at 1100°C and 5×10⁻⁷ Torr. Current-voltage characteristics were linear for CrB₂ and W₂B and quasi-linear for TiB₂. The lowest values of the specific contact resistance (r_c in Ω-cm²) measured at room temperature for CrB₂ and W₂B were 8.2×10⁻⁵ and 5.8×10⁻⁵, respectively. The specific contact resistance for TiB₂ was not determined accurately. Longer anneals (30 min for W₂B and 90 min for CrB₂) reduced the room temperature values of r_c to 6.1×10⁻⁵ for W₂B and 1.9×10⁻⁵ for CrB₂. Backscattering spectra revealed substantial concentrations of oxygen in all as-deposited boride films. The short anneal cycle removed the oxygen in the CrB₂ films and reduced the concentration substantially in the W₂B films; however, annealing had no affect on the oxygen concentration in the TiB₂ films. The CrB₂/SiC interface remained stable during annealing; i.e., Si and carbon were not observed in the boride layers after annealing. In contrast, W₂B and TiB₂ reacted with the SiC epilayers, and after annealing, Si and carbon were observed at the surface of each boride layer.     

New BETS salts based on magnetic (CuCl3, FeCl4) and non-magnetic (GaCl4) anions

New BETS salts (where BETS is bis(ethylenedithio)tetraselenafulvalene) with (CuCl₃)_x, Cu₂C₆, Cu₄Cl₈ and Fe_0.75Ga_0.25Cl₄ anions have been obtained. The crystal structures and electrical and magnetoresistance properties of K-BETS₄Cu₄Cl₈, θ-BETS₄Cu₂Cl₆ and K-BETS₂Fe_0.75Ga_0.25Cl₄ have been studied. The last two compounds have been found to exhibit Shubnikov-de Haas and angle-dependent magnetoresistance oscillations. © 1997 John Wiley & Sons, Ltd.     

Micro- and Nano-Technology: A Critical Design Key in Advanced Thermoelectric Cooling Systems

Advanced thermoelectric (TE) cooling technologies are now receiving more research attention, to provide cooling in advanced vehicles and residential systems to assist in increasing overall system energy efficiency and reduce the impact of greenhouse gases from leakage by current R-134a systems. This work explores the systems-related impacts, barriers, and challenges of using micro-technology solutions integrated with advances in nano-scale thermoelectric materials in advanced TE cooling systems. Integrated system-level analyses that simultaneously account for thermal energy transport into and dissipation out of the TE device, environmental effects, temperature- dependent TE and thermo-physical properties, thermal losses, and thermal and electrical contact resistances are presented, to establish accurate optimum system designs using both p-type nanocrystalline-powder-based (NPB) Bi _x Sb_2−x Te₃/n-type Bi₂Te₃-Bi₂Se₃ TE systems and conventional p-type Bi₂Te₃-Sb₂Te₃/n-type Bi₂Te₃-Bi₂Se₃ TE systems. This work established the design trends and identified optimum design regimes and metrics for these types of systems that will minimize system mass, volume, and cost to maximize their commercialization potential in vehicular and residential applications. The relationships between important design metrics, such as coefficient of performance, specific cooling capacity, and cooling heat flux requirements, upper limits, and critical differences in these metrics in p-type NPB Bi _x Sb_2−x Te₃/ n-type Bi₂Te₃-Bi₂Se₃ TE systems and p-type Bi₂Te₃-Sb₂Te₃/n-type Bi₂Te₃-Bi₂Se₃ TE systems, are explored and quantified. Finally, the work discusses the critical role that micro-technologies and nano-technologies can play in enabling miniature TE cooling systems in advanced vehicle and residential applications and gives some key relevant examples. Pacific Northwest National Laboratory—operated for the U.S. Department of Energy by Battelle Memorial Institute under contract DE-AC05-76RLO1830.     

Electrical, optical, and thermodynamical aspects of sound propagation in HgTe, HgSe, Hg1−xMnxSe, and MnZn spinel ferrites

Sound velocity was measured in Hg_1−xMn_xSe semimagnetic semiconductor and Mn_1−xZn_xFe₂O₄ spinel ferrite, calculated for HgSe and HgTe, and related to existing data for ZnS structure-type materials. Useful systematics are established, and some of the unknown parameters of Hg_1−xMn_xSe anticipated. In addition, Hg_1−xMn_xSe and Mn_1−xZn_xFe₂O₄ were exposed to laser radiation in an attempt to relate sound velocity, Brillouin shift, and laser-beam-induced material breakdown. Interesting features were pointed out, as well as capabilities of opto-acoustic measurements to relate chemistry and elastic and magnetic properties of materials or help in the evaluation of infrared absorption spectra. Applicability and limitations of some conventional theories and empirical formulas are deduced.     

Monoethylarsine pyrolysis mechanisms—alone and with trimethylgallium

Pyrolysis of monoethylarsine (C₂H₂AsH₂), alone and with trimethylgallium ((CH₃)₃Ga), has been studied at atmospheric pressure in a flow tube reactor using mass spectrometry. He and D₂ were selected as the carrier gases to determine the ambient effects and to isotopically label the pyrolysis products. Supplemental C₂H₅ and CH₃ radicals, produced from pyrolysis of azoethane ((C₂H₅)₂N₂) and azomethane ((CH₃)₂N₂), were added for some experiments to investigate the role of radicals in pyrolysis. No ambient effect appeared; however, the pyrolysis could be enhanced by addition of either C₂H₅ or CH₃ radicals. Enhanced pyrolysis also occurred when (CH₃)₃Ga was added. The products for pyrolysis alone and with (C₂H₅)₂N₂ were nearly identical, mainly C₂H₆ and small amounts of diethylarsine ((C₂H₅)₂AsH) and AsH₃. However, with (CH₃)₂N₂ and (CH₃)₃Ga, in addition to the major products C₂H₆ and CH₄, other CH₃-associated species were observed. These results suggest that (1) C₂H₅AsH₂ alone pyrolyzes via C₂H₅ radical reactions and (2) with (CH₃)₃Ga, CH₃ radical reactions are important decomposition pathways. Pyrolysis of (C₂H₅)₂AsH and triethylarsine ((C₂H₅)₃As), alone and with (CH₃)₂Ga, are compared. A generalized theory for pyrolysis in all three ethylarsine systems is suggested. The main role of (CH₃)₃Ga during growth of GaAs using (CH₃)₃Ga and any of the ethylarsines is probably the supply of CH₃ radicals which abstract H or C₂H₅ ligands from the ethylarsine parent molecules.