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     

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、     

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、...     

冬季常吃四类水果有益健康

冬季首选的水果有:梨、甘蔗、柚子、柑橘。梨梨中含苹果酸、柠檬酸、葡萄糖、果糖、钙、磷、铁以及多种维生素,且有润喉生津、润肺止咳、滋     

2009厦门·华协体高峰会议隆重召开

2009年11月6日,由华东电视技术协作体主办、厦门广播电视集团承办的“2009厦门·华协体高峰会议”在厦门市马哥孛罗大酒店隆重举行。来自江苏、上海、浙江、福建、安徽、江西、山东、厦门、杭州、南京、济南等11家电视媒体;索尼、松下、新奥特、大洋、索贝、哈里斯、安达斯、安恒利、STR、捷成世纪、北京星光等11家厂商以及《广播与电视技术》、     

业余无线电通信卫星的魅力

从1961年至今全世界已经研制和发射的业余卫星超过一百颗,参与策划、设计和制造业余卫星的国家包括美国、澳大利亚、德国、英国、法国、俄国、日本、意大利、芬兰、挪威、新西兰、韩国、墨西哥、哥伦比亚、以色列、泰国、智利、巴西、阿根廷、葡萄牙、南非、沙特阿拉伯、马来西亚、印度等发达国家和发展中国家,参加业余卫星通信活动的业余无线电爱好者以及体检过业余卫星通信的青少年学生更是遍及全世界的每个角落。我国的业余无线电爱好者也已完成业余卫星的研制,正在积极筹备准备发射。     

本刊来稿须知

1．本刊设有专题论坛、专业改革、教学改革、课程改革、自动控制、教学研究、电子信息、电气工程、教材建设、实践教学、教学方法、机辅教学、争鸣论坛、高职教育、教学仪器及电坛人物等栏目。     

行业资讯

发改委联合工信部召开大数据发展和应用工作研讨会 近日，发改委高技术司与工信部软件司共同组织召开促进大数据发展和应用工作研讨会，分别邀请国办、教育部、科技部、公安部、安全部、财政部、人社部、环保部、交通部、卫生计生委、人民银行、审计署、工商总局、质检总局、食药总局、统计局、国务院法制办、银监会、证监会等20部门相关负责同志及郭华东、李国杰、吴曼青等院士专家进行了交流。     

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。     

Avalanche Mechanism in p +-n −-n + and p +-n Mid-Wavelength Infrared Hg1−x Cd x Te Diodes on Si Substrates

Hg_1−x Cd _x Te mid-wavelength infrared (MWIR) p ⁺-n ⁻-n ⁺ and p ⁺-n ⁻ avalanche photodiodes (APDs) with a cut-off of 4.9 μm at 80 K were fabricated on Si substrates. Diode characteristics, avalanche characteristics, and excess noise characteristics were measured on two devices. Temperature-dependent diode and avalanche characterization was performed. Maximum 3 × 10⁶ Ω cm² and 9 × 10⁵ Ω cm² zero-bias resistance times active area (R ₀ A) products were measured for the p ⁺-n ⁻-n and p ⁺-n devices at 77 K, respectively. Multiplication gains of 1250 and 410 were measured at −10 and −4 V for the p ⁺-n ⁻-n ⁺ and p ⁺-n APDs at 77 K, respectively, in the front-illumination mode with the help of a laser with an incident wavelength of 632 nm. The gains reduce to 200 and 50 at 120 K, respectively. The excess noise factor in all APDs was measured to be in the range of 1 to 1.2.     

Nickel silicidation techniques for strained Si1?xGex, Si1?x?yGexCy, and Si1?yCy alloys material-device applications

A nickel silicide process for Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloy materials compatible with Si technology has been developed. Low-resistivity-phase (12–20 μΘ cm) nickel silicides have been obtained for these alloys with different low sheet-resistance temperature windows. The study shows that thin (15–18 nm) silicide layers with high crystalline quality, smooth silicide surface, and smooth interface between silicide and the underlying material are achievable. The technique could be used to combine the benefits of Ni silicide and Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloys. The technique is promising for Si or Si_1-xGe_x, Si_1-x-yGe_xC_y, and Si_1-yC_y alloy-based metal-oxide semiconductor, field-effect transistors (MOSFETs) or other device applications.     

Novel diarylborane–phenanthroimidazole hybrid bipolar host materials for high-performance red,yellow and green electrophosphorescent devices

In this work, two novel bipolar host materials p-BPPI and m-BPPI containing phenanthroimidazole/dimesitylborane (Mes₂B) with para- and meta-linkage have been designed, synthesized and characterized. The appending Mes₂B moiety improves the thermal stability, electrochemical stability and carrier injection/transport ability of both target compounds. The test results of time-of-flight (TOF) and single-carrier devices show that both the new hosts possess bipolar charge-transporting characteristics. As a result, series of highly efficient green (66.3 cd A⁻¹, 63.1 lm W⁻¹, 18.2%), yellow (55.2 cd A⁻¹, 66.6 lm W⁻¹, 14.5%) and red (20.1 cd A⁻¹, 20.4 lm W⁻¹, 13.5%) PhOLEDs are achieved by using them as the universal host materials. The results indicate that bipolar host p-BPPI and m-BPPI have high potential in fabricating various color OLEDs for displays and lighting applications. Our study further enriches the selection of D and A group for phosphorescent host materials. The relationship between molecular structures and optoelectronic properties is discussed experimentally and theoretically.     

On the profile of frequency dependent series resistance and dielectric constant in MIS structure

In this study, the frequency dependent of the forward and reverse bias capacitance-voltage (C-V) and conductance-voltage (G/ω - V) measurements of Al/SiO₂/p-Si (MIS) structures are carried out in frequency range of 10 kHz-10 MHz. The frequency dependence of series resistance (R_s), density of surface states (N_ss), dielectric constant (ε′), dielectric loss (ε″), dielectric loss tangent (tan δ) and the ac electrical conductivity (σ_dc) are studied for these structure at room temperature. Experimental results show that both electrical and dielectric parameters were strongly frequency and voltage dependent. The ε′ and ε″ are found to decrease with increasing frequency while σ_ac is increased. Also, both the effects of surface states N_ss and R_s on C-V and G/ω - V characteristics are investigated. It has been seen that the measured C and G decrease with increasing frequency due to a continuous distribution of N_ss in frequency range of 10 kHz-1 MHz. The effect of R_s on the C and G are found noticeable at high frequencies. Therefore, the high frequencies C and G values measured under both reverse and forward bias were corrected for the effect of series resistance R_s to obtain real MIS capacitance C_c and conductance G_c using the Nicollian and Goetzberger technique. The distribution profile of R_s-V gives a peak in the depletion region at low frequencies and disappears with increasing frequencies.     

Nearly Perfect Electrical Activation Efficiencies from Silicon-Implanted Al<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Ga<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>N with High Aluminum Mole Fraction

Electrical activation studies of Al _x Ga_1−x N (x = 0.45 and 0.51) implanted with Si for n-type conductivity have been made as a function of ion dose and anneal temperature. Silicon ions were implanted at 200 keV with doses ranging from 1 × 10¹⁴ cm⁻² to 1 × 10¹⁵ cm⁻² at room temperature. The samples were subsequently annealed from 1150°C to 1350°C for 20 min in a nitrogen environment. Nearly 100% electrical activation efficiency was successfully obtained for the Si-implanted Al_0.45Ga_0.55N samples after annealing at 1350°C for doses of 1 × 10¹⁴ cm⁻² and 5 × 10¹⁴ cm⁻² and at 1200°C for a dose of 1 × 10¹⁵ cm⁻², and for the Al_0.51Ga_0.49N implanted with silicon doses of 1 × 10¹⁴ cm⁻² and 5 × 10¹⁴ cm⁻² after annealing at 1300°C. The highest room-temperature mobility obtained was 61 cm²/V s and 55 cm²/V s for the low-dose implanted Al_0.45Ga_0.55N and Al_0.51Ga_0.49N, respectively, after annealing at 1350°C for 20 min. These results show unprecedented activation efficiencies for Al _x Ga_1−x N with high Al mole fractions and provide suitable annealing conditions for Al _x Ga_1−x N-based device applications.     

Magneto-optical Studies of Spin Phenomena in CdMnTe Doped with Co and Cr

We investigate the magneto-optical and magnetic properties of two quaternary diluted magnetic semiconductor alloys, Cd_1−x−y Mn _x Cr _y Te and Cd_1−x−y Mn _x Co _y Te, with fixed Mn concentration x ∼ 0.37 and, respectively, with concentrations of Cr in the range 0 < y < 0.07 and Co in the range␣0 < y < 0.009. The introduction of Cr and Co leads to very different behaviors, including the occurrence of ferromagnetic order in the case of Cd_1−x−y Mn _x Cr _y Te. We discuss the possible origins leading to the observed behaviors.     

Frequency and temperature dependence of the dielectric and AC electrical conductivity in (Ni/Au)/AlGaN/AlN/GaN heterostructures

The dielectric properties and AC electrical conductivity (σ_ac)of the (Ni/Au)/Al_0.22Ga_0.78N/AlN/GaN heterostructures, with and without the SiN_x passivation, have been investigated by capacitance-voltage and conductance-voltage measurements in the wide frequency (5kHz-5 MHz) and temperature (80-400 K) range. The experimental values of the dielectric constant (ε′), dielectric loss (ε′′), loss tangent (tanδ), σ_ac and the real and imaginary part of the electric modulus (M′ and M′′) were found to be a strong function of frequency and temperature. A decrease in the values of ε′ and ε′′ was observed, in which they both showed an increase in frequency and temperature. The values of M′ and M′′ increase with increasing frequency and temperature. The σ_ac increases with increasing frequency, while it decreases with increasing temperature. It can be concluded, therefore, that the interfacial polarization can occur more easily at low frequencies and temperatures with the number of interface states density located at the metal/semiconductor interface. It contributes to the ε′ and σ_ac.     

GaN Nanowire Carrier Concentration Calculated from Light and Dark Resistance Measurements

We obtained the carrier concentration and mobility of silicon-doped gallium nitride nanowires at room temperature with light and dark resistance data. Current–voltage measurements were performed on single-nanowire devices in the dark and under 360 nm illumination. Field-emission scanning electron microscopy was used to measure the device dimensions. The nanowires were modeled with cylindrical geometry, and solutions were computed with a nonlinear fit algorithm. Simulations were also performed to verify the model. The carrier concentration was bounded by 6 × 10¹⁷ cm⁻³ and 1.3 × 10¹⁸ cm⁻³, and the mobility was between 300 cm² V⁻¹ s⁻¹ and 600 cm² V⁻¹ s⁻¹.     

Morphology and mechanical properties of intermetallic compounds in SnAgCu solder joints

This paper presents the studies to determine hardness and elastic modulus of intermetallic compound (IMC) layers in lead-free solder joints using nanoindentation technique. Two types of surface finishes, i.e., organic solderability preservative (OSP) and electrolytic Ni/Au on Cu pad, with Sn3.5Ag0.5Cu solder balls of 330 μm in diameter are studied, and the intermetallic layers are identified to be Cu₆Sn5, Cu₃Sn and (Ni_y,Cu_1−y)₃Sn₄. The thicknesses of these IMC layers are only few microns at reflowed conditions (less than 2.3 μm). Therefore, probing mechanical properties of thinner IMCs using nanoindentation techniques poses immense difficulties and challenges. In this study, taper-mounted samples are used rather than standard cross-sectional mounted for solder joints. This taper sample gives a larger area for nanoindentation measurements. The elastic modulus and hardness of IMC layers are determined based on the parameter P/S² (load/stiffness²) as a function of the indentation depth to minimise the effects of underlying UBM or solder materials. The modulus of Cu₆Sn₅, Cu₃Sn, (Cu_x,Ni_1−x)₆Sn₅ and (Ni_y,Cu_1−y)₃Sn₄ layer are found to be 112.0 ± 5.1 GPa, 135.5 ± 4.3 GPa, 165.0 ± 11.3 GPa and 136.8 ± 5.8 GPa; whereas the hardness values are found to be 6.8 ± 0.4 GPa, 6.6 ± 0.5 GPa, 7.2 ± 0.9 GPa and 8.2 ± 1.0 GPa, respectively. Thus, the IMC layers in the order of increasing hardness and modulus are found to be Cu₆Sn₅, Cu₃Sn, (Cu_x,Ni_1−x)₆Sn₅ and (Ni_y,Cu_1−y)₃Sn₄.     

On the profile of frequency dependent series resistance and surface states in Au/Bi4Ti3O12/SiO2/n-Si(MFIS) structures

The frequency dependent capacitance-voltage (C-V) and conductance-voltage (G/ω-V) characteristics of the metal-ferroelectric-insulator-semiconductor (Au/Bi₄Ti₃O₁₂/SiO₂/n-Si) structures (MFIS) were investigated by considering series resistance (R_s) and surface state effects in the frequency range of 1 kHz-5 MHz. The experimental C-V-f and G/ω-V-f characteristics of MFIS structures show fairly large frequency dispersion especially at low frequencies due to R_s and N_ss. In addition, the high frequency capacitance (C_m) and conductance (G_m/ω) values measured under both reverse and forward bias were corrected for the effect of series resistance to obtain the real capacitance of MFIS structures. The R_s-V plots exhibit anomalous peaks between inversion and depletion regions at each frequency and peak positions shift towards positive bias with increasing frequency. The C⁻²-V plot gives a straight line in wide voltage region, indicating that interface states and inversion layer charge cannot follow the ac signal in the depletion region, but especially in the strong inversion and accumulation region. Also, it has been shown that the surface state density decreases exponentially with increasing frequency. The C-V-f and G/w-V-f characteristics confirm that the interface state density (N_ss) and series resistance (R_s) of the MFIS structures are important parameters that strongly influence the electrical properties of MFIS structures.