GSMBE InGaP/GaAs材料大面积均匀性研究

报道了气态源分子束外延 (GSMBE)技术生长的Φ5 0mm ,Φ75mmInGaP/GaAs材料的晶体完整性 ,组分均匀性和表面缺陷密度。用PhilipsX Pert′s四晶衍射仪沿Φ5 0mm ,Φ75mmInGaP/GaAs样品的x轴和y轴以 5mm间隔测量ω/2θ双晶摇摆曲线 ,获得沿x轴和y轴方向的晶格失配度分布和组分涨落分布。结果表明 ,用GSMBE生长的Φ5 0mm和Φ75mmIn0 .4 9Ga0 .51 P与GaAs衬底的失配度分别为 1× 10 - 4和 1× 10 - 5,组分波动Φ5 0mm沿x轴和y轴分别为± 0 .1%和± 0 .2 % ,Φ75mm <± 1%。表面缺陷密度在 1× 10～ 1× 10 2 cm- 2 。     

铬蓝黑-R褪色分光光度法测定铬(Ⅵ)

在硫酸介质中,Cr(Ⅵ)氧化铬蓝黑 R使其褪色,且褪色程度与Cr2O2-7的含量呈线性关系,据此建立了测定微量铬(Ⅵ)的分光光度新方法。Cr(Ⅵ)量在0～0.80mg/L范围内符合比尔定律,表观摩尔吸光系数ε=1.4×105,该法所用试剂种类少,简单快速,用于钢样中微量铬的测定,结果满意。     

硅中载流子浓度的红外自由载流子吸收测定法

硅材料和硅器件的许多性质和性能都与载流子浓度有直接依赖关系。测定硅中载流子浓度已发展有许多方法,如四探针法、霍耳系数法,C-V法、光致荧光法、杂质吸收法等等。1958年吴仲墀等人利用室温下10.6μm处自由载流子的吸收系数α测定硅中载流子浓度,作者则采用在500～3500cm~(-1)红外波段内测量的吸收系数α,得到了载流子浓度N。     

温度梯度法制备CeF_3光学镀膜材料的工艺研究

以自制的CeF_3粉体为原料,在真空碳管炉中采用温度梯度法制备了CeF_3晶体。通过X射线衍射(XRD)、扫描式电子显微镜(SEM)、能谱分析(EDS)等分析方法对不同影响因素下的产物进行表征,CeF_3晶体进行镀膜实验,并对所得膜层进行光学性能测试。结果表明:采用钨坩埚,在1×10-2Pa真空度下1500℃保温1 h,以100℃·h-1的温度梯度降温,可制备得结晶性能良好的CeF_3晶体。添加NH4HF2作为脱氧剂可以使产物中氧含量从0. 54%(质量分数)降低到0. 1%。采用两种氧含量的CeF_3晶体分别进行镀膜实验,氧含量较低的晶体,其镀膜速率波动曲线较稳定,在±0. 05 nm·s-1之间波动,说明氧含量的降低可显著改善材料的蒸发特性;镀膜残余由发黑、发白、黑白过度三部分组成,其发黑部分氧含量最高为7. 92%。CeF_3膜层性能测试表明,在波长为550 nm处,折射率为1. 6,吸收系数为3×10-4。     

定向凝固合金DZ466在涂 NaCl/Na2 SO4盐条件下热腐蚀行为

采用涂Na Cl/Na2SO4盐方法研究了DZ466合金在850℃和950℃条件下热腐蚀行为.结果表明:合金的腐蚀层包括三个区域,最外层为(Ni,Co)O氧化物层,次外层为尖晶石结构氧化层(Ni,Co)Cr2O4,内层为内腐蚀层,850℃时该层为Ni3S2,而950℃时除Ni3S2外,在靠近次外层还形成内氧化Al2O3;在850℃和950℃时合金的热腐蚀机制相同,氧化膜连续性的破坏,是合金遭受热腐蚀的主要原因;热腐蚀增重曲线均符合抛物线规律,其速率常数分别为3.1×10-11g2·cm-4·s-1和1.5×10-9g2·cm-4·s-1,热腐蚀激活能分别为179.2 k J·mol-1和138.3 k J·mol-1.     

掺硅的GaAs体单晶的补偿比及载流子浓度的分布

采用红外吸收法测定熔体生长掺硅的GaAs单晶的补偿比。实验结果表明:当2×10~172×10~18/厘米~3,θ分别随n的减少或增加而增加。 从施主、受主浓度的分布是同步的,以及沿锭长分布符合定向凝固的杂质分凝规律,提出与杂质硅有关的Si_(As)和Si_(Ga)·V_(Ga)为主要补偿受主,并讨论了Si的掺杂行为。 垂直于晶体生长方向的试样的n,N_D和N_A的分布特征,表明N_A似乎是影响均匀性的主要缺陷。根据实验结果,简要地讨论改进均匀性和减小补偿比的一些措施。     

高温质子导体BaCe0.90 Y0.10 O3-α的制备与性质

对不同球磨时间的BaC03,CeO2和Y2O3原料粉体进行固相反应,合成了不同粒度的BaCe0.90Y0.10O3-α粉体.将其冷压成型、高温烧结后,获得了不同致密度的BaCe0.90 Y0.10 O3-α样品.利用激光粒度分析、差式扫描量热-热重、X射线衍射和扫描电镜技术研究了球磨时间对粉体粒度、合成过程、晶体结构及样品微观形貌的影响.结果表明:适度延长球磨时间,原料颗粒细化,BaCe0.90 Y0.10 O3-α的合成温度降低,合成粉体的粒度变小、分布变窄、比表面积增大,从而提高了烧结样品的致密度.利用电化学阻抗谱技术测量了原料球磨6 h和10 h的BaCe0.90 Y0.10 O3-α烧结样品在空气中573～1 073 K内的阻抗谱,并计算出其电导率分别为3.25×10-3～6.98×10-2 S·cm-1和5.46×10-3～7.20×10-2S·cm-1.在测试温度范围内,两种样品的电导率与温度的关系符合Arrhenius方程,电导激活能分别为0.39 eV和0.34 eV.提高烧结样品的致密度是降低电导激活能,提高导电性能的有效途径.BaCe0.90 Sm0.10 O3-α,BaCen0.90 Y0.10 O3-α和BaCe0.85 Y0.15 O3-α的电导激活能依次降低,符合理论预测.     

氧化铬细粉粒度对铬铝锆砖性能的影响分析

为了改善水煤浆加压气化炉用铬铝锆砖的物理性能及抗煤熔渣渗透性能,提高其使用寿命,固定基质中氧化铬细粉的量不变,改变Cr2O3细粉的粒度,研究了中位径(D50)分别为5μm、10μm、25μm和40μm的Cr2O3细粉的加入对铬铝锆砖体积密度、常温强度、高温抗折强度、热震稳定性及抗煤熔渣侵蚀性的影响。结果表明:本实验条件下,Cr2O3细粉粒度对试样体积密度的影响较小;随Cr2O3细粉粒度的增大,试样的常温抗折及耐压强度、高温抗折强度先增加后降低,热震后残余强度及残余强度保持率增加;加入的Cr2O3细粉的粒度为25μm时,试样的物理性能及抗渣渗透性较好。     

Ba2TiSi2O8晶体的质量表征及其性能研究

通过不断探索生长工艺及生长参数,采用提拉法成功生长了尺寸约为35 mm×35 mm×50 mm的Ba2TiSi2O8晶体,所得晶体均匀透明无开裂,用绿光激光笔照射,没有明显散射颗粒。表征了晶体质量,并对其透过光谱和室温偏振拉曼光谱性能进行了研究。采用高分辨X射线衍射技术对晶体的质量进行了表征,衍射峰较窄,没有劈裂,且分布对称,说明生长的晶体晶格完整、品质较好,能够满足晶体某些光学方面的需求。用分光光度计测量了晶体的室温透过光谱,晶体[100]方向和[001]方向上的透过率接近,在340～2500 nm范围内其透过率大约为84%,晶体的紫外透过截止波长为275 nm,高的透过率以及短的紫外透过截止波长,表明该晶体可能在光学方面有一定应用。采用共聚焦纤维拉曼光谱仪测量了晶体在背散射X(ZZ)X,X(YY)X,Z(XY)Z和X(YZ)X配置下的室温偏振拉曼光谱,并指认了某些测定的特征峰:662 cm-1属于桥对称伸缩振动νs(Si-O-Si),578,625,749,858,876 cm-1属于ν(Ti-O)振动,858,901,930,993和1022 cm-1属于ν(SiO3)振动。     

用溅射沉积生长高质量的GaAs外延膜

近来,溅射法已用于各种单晶元素、化合物、合金和超晶格半导体的生长。对于Ⅲ-Ⅴ族化合物半导体来说,单晶的生长大多与诸如InSb、GaSb、In_(1-x)Ga_xSb、InSb_(1-x)Bi_x和InSb/GaSb超晶格的Sb基化合物和合金有关。从非掺杂的GaAs源中,通过溅射沉积法在(100)掺Cr的GaAs衬底上生长GaAs外延膜。非故意掺杂的样品为n型高阻(10~5～10~9Ω·cm),室温迁移率高达5000cm~2/v·     

China's Major Non-ferrous Metals Imports & Exports

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Zinc Production by Province in 2014

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80% of Chinese Firms Purchasing Overseas Mines Ended up in the Red

<正>Minmetals Resources acquired the world’s largest copper mine under construction for USD5.85 billion.One after another,listed companies Jien Nickle,China Molybdenum and Chihong Zinc and Germanium raised money to get involved in overseas mining projects…SOEs and private enterprises are engaged in a frenzy of overseas mine purchasing.A reporter with Economic     

Copper Processing Profit Dropped Sharply,Copper Consumption Will Face Impact in the Second Half of the Year

正Judging from China’s copper consumption field,the biggest consumption unit is electric power,which accounts for 47%of total consumption;it is followed by light industry sector,including household electrical appliance,machinery,durable goods and hardware etc,which accounts for 22%of total consumption;followed by transportation field,     

Central Geological Prospecting Fund Newly Added 16.47 Million Tonnes of Bauxite in 2013

正In 2013,the Central Geological Prospecting Fund(CGPF)Project newly discovered 15 ore fields,including 3 large above ore fields,and 5medium sized ore fields.The reporter learned from the recently published"Annual Report of Central Geological Prospecting Fund Project(2013)"that,from 2006 to 2013 the CGPF     

Manufacturers of Copper Tube for Central Air Conditioner Use Face Mounting Pressure in the Final Quarter of the Year

正This year,the investment growth rate of real estate industry continued to slow down,sold area of commercial housing also dropped significantly,which brought huge pressure to the domestic air conditioning manufactures.In the first half of the year,by relying on high growth in national financial expenditure,along with investment in public infrastructure     

Xinjiang Ranks No.1 in Production of Primary Aluminum in China

正Kang Yi,Honorary Chairman of China Nonferrous Metals Industry Association,said recently at the Forum on Development of the Non-ferrous Metals Industry in Central and Western China held in Zhengzhou that,as more and more electrolytic aluminum factories in Xinjiang came into operation,the electrolytic aluminum output of Xinjiang had reached2,275,000 tons in the first 7 months this year,     

Shenhuo Coal Industry and Electricity Power Completed800,000 t/a Aluminum Project in Xinjiang

正"Xinjiang project has been completed according to schedule,but total completion and total start of production are two different concepts,after completion it still needs a gradual process of reaching production target."On the morning of November 3,Shenhuo Coal Industry and Electricity Power told investors the above statement on the investor interaction platform.     

Guangdong Metal Transaction Center has Become the Second Largest Precious Metal Transaction Platform Nationwide

正The reporter learned from Guangdong Province Precious Metal Transaction Center that in 2013the Center maintained healthy development momentum,and had become the second largest precious metal transaction platform in China in terms of market size;currently Guangdong is quickening steps of financial innovation for the Center,aiming to build a transaction center with international core competitiveness.     

Seven Rare Earth Projects Involving Close to 3 Billion Yuan Investment Landed In the HighTech Zone

正On May 22,Baotou Rare Earth Industry Cooperation Consultation MeetingProject Agreement-signing Ceremony was held in Ningbo,nearly 40 enterprises from Ningbo,Guangdong,Hunan,and Shanxi participated in project consultation.After multi-lateral communication,agreements were signed for a total of 7 rare earth projects successfully.