连续输出20WAlGaAs／GaAs量子阱激光二极管线列阵

采用ＭＯＣＶＤ实现了ＡｌＧａＡｓ／ＧａＡｓ量子阱结构，获得了连续输出２０Ｗ激光二极管线列阵，线列阵长度１．０ｃｍ，激射波长８０８±４ｎｍ。     

国产金属有机化合物TMGa,TMAl,TMIn和TMSb的MOVPE鉴定

利用我们研制的常压ＭＯＶＰＥ设备对国产ＴＭＧａ、ＴＭＡｌ、ＴＭＩｎ和ＴＭＳｂ进行了鉴定，为此分别生长了ＧａＡｓ、ＡｌＧａＡｓ、ＩｎＰ、ＧａＳｂ外延层和ＧａＡｓ／ＡｌＡｓ、ＧａＳｂ／ＩｎＧａＳｂ超晶格和ＧａＡｓ／ＡｌＧａＡｓ量子阱结构。表征材料纯度的７７Ｋ载流予迁移率分别达到ＧａＡｓ：μ＿ｎ＝５６６００ｃｍ￣２／Ｖ·ｓ，Ａｌ＿（０．２５）Ｇａ＿（０．７５）Ａｓ：μ＿ｎ＝５１６０ｃｍ￣２／Ｖ·ｓ，ＩｎＰ：μ＿ｎ＝６５３００ｃｍ￣２／Ｖ·ｓ，ＧａＳｂ：μ＿ｐ＝５０７６ｃｍ￣２／Ｖ·ｓ。由１０个周期的ＧａＡｓ／ＡｌＡｓ超晶格结构组成的可见光区布拉格反射器已观测到很好的反射光谱和双晶Ｘ射线回摆曲线上高达±２０级的卫星峰。ＧａＡｓ／Ａｌ＿（０．３５）Ｇａ＿（０．６５）Ａｓ量子阱最小阱宽为１０，在ｌｉＫ下由量子尺寸效应导致的光致发光峰能量移动为３９０ｍｅＶ，其线宽为１２ｍｅＶ。这些结果表明上述金属有机化合物已达到较高质量。     

量子点激光器及其应用研究

报道了分子束外延生长出自组装垂直耦合ＩｎＡｓ／ＧａＡｓ大功率量子点激光器材料和器件。对腔长为８００μｍ,室温下和７７Ｋ下边续激射阈值电流密度分别为２１８Ａ／Ｃｃｍ＾２和４９Ａ／ｃｍ＾２,波长为９６０ｎｍ,最大输出功率大于１Ｗ。首次报道在０．５４Ｗ工作下,寿命超过３０００小时,功率仅下降０．４９display status０     

光阴极材料GaAs／AlGaAs的组分分析

为探索砷化我阴极的光电灵敏度的影响因素,利用Ｘ射线光电子能谱、二次离子擀谱和电化学方法测试和分析了国内和国外ＧａＡｓ光阴极材料ＧａＡｓ／ＡｌＧａＡｓ的Ｃ,Ｏ含量的空穴深度分布。实验发现,国内的材料在ＧａＡｓ／ＡｌＧａＡｓ 面及ＡｌＧａＡｓ层的Ｏ含量分别为７．６％和１０．６％,Ｃ深度分别为５．２×１０＾１８ａｔｏｍｓ／ｃｍ＾３和１．０×１０＾１９ａｔｏｍｓ／ｃｍ＾３,而国外的材料的Ｏ含量相应为１．０     

电子束蒸镀半导体发光二极管的减反射膜

用电子束蒸发设备，制备了用于光纤通信等中的ＧａＡｓ和ＩｎＰ系列双异质结红外发光二级管的减反射介质膜。测量结果表明，对发光波长为０．８５μｍ和０．９０μｍ的ＧａＡｌＡｓ／ＧａＡｓ发光二级管，蒸镀四分之一波长厚的Ａｌ２Ｏ３减反射膜，输出光功率在５０ｍＡ和１００ｍＡ电流注入下，可增加２５￣３５％，最大可增加５０％。但对于１．３μｍ波长的ＩｎＧａＡｓＰ／ＩｎＰ型红外发光二极管，用ＺｒＯ２作减反射膜，比用Ａ     

Cs／p—GaAs（100）表面的变角XPS研究

在实验数据的基础上，采用变角ＸＰＳ分析表面层状结构的计算程序，应用了新算法，使该程序能快速可靠地计算多层多种组分的含量和层厚度。计算了Ｃｓ吸附在清洁ｐ－ＧａＡｓ（１００）表面上的Ｃｓ层覆盖率及弛豫层的厚度和组分。在Ｃｓ／ＧａＡｓ达到峰值光电发射时，Ｃｓ覆盖率为０．７１个单层，Ｇａ、Ａｓ弛豫层厚度为２．３个单层，Ｇａ相对．Ａｓ轻微富集。     

0.1-0.3μmX射线光刻技术在GaAs器件制作中的应用

对同步辐射Ｘ射线光刻及在ＧａＡｓ ＰＨＥＭＴ器件制作中的应用进行了研究,并制作出栅长０．１５μｍ的ＡｌＧａＡｓ／ＩｎＧａＡｓ／ＧａＡｓ ＰＨＥＭＴ晶体管。研究结果表明,Ｘ射线光刻在肃离图形册结构制作工艺中具有极好的光刻图形质量,在混合光刻工艺中,抑止ＧａＡｓ合金点的形成是取得良好的对准标记的关键。     

金属夹层对Ge／GaAs（100）能带偏离影响的研究

用光电发射的方法研究了碱金属Ｎａ和碱土金属Ｍｇ对Ｇｅ．ＧａＡｓ（１００）异质结构形成及能带偏离的影响。实验结果表明，Ｎａ和Ｍｇ的薄夹层可使Ｇｅ／ＧａＡｓ（１００）的价带偏离分别增加０．１９和０．１８ｅＶ。通过Ｎａ，Ｍｇ和Ａｌ夹层的对比研究，可认为金属夹层对异质结能带偏离的影响与金属的电负性及其与衬底的相互作用有关。     

亚毫安室温连续工作InGaAs垂直腔面发射激光器

报道了ＩｎＧａＡｓ应变量子讲垂直腔面发射激光器（ＶＣＳＥＬ）的室温连续工作。在ＭＢＥ生长过程中利用红外高温仪测量了表观衬底热辐射振荡，实现了原位厚度监测；采用阶梯型分布布拉格反射器（ＤＢＲ）及腐蚀倒台面结构，降低了器件串联电阻。对于２×３μｍ２的台面结构ＶＣＳＥＬ，室温连续工作阈值电流一般为１．５ｍＡ，最低达到０．７ｍＡ，阈值电压为２．５伏，输出功率达到０．５ｍＷ，激射波长为０．９４ｕｍ，量子效率为１２％。     

电子束蒸镀半导体光电器件的增透膜

用自动电子束蒸发设备，蒸镀用于光纤通信等中的ＧａＡｓ和ＩｎＰ系列双异质结红外发光二极管的增透膜。结果表明，对波长为０．８μｍ左右的ＧａＡｌＡｓ／ＧａＡｓ发光二极管，蒸镀四分之一波长厚的Ａｌ２Ｏ３介质膜后，其输出光功率在５０ｍＡ和１００ｍＡ电流注入，可增加２５－３５％，最大可增加－５０％。对１．３μｍ波长的ＩｎＰ系列红餐发光管，用ＺｒＯ２作介质增透膜效果更好。     

Difference of histology and elemental composition of the cervical enamels among human permanent teeth

The purpose of this study is to clarify the difference of histology and elemental composition of the cervical enamels among the human permanent teeth. The reground surfaces at the cervical enamels of them were observed under scanning electron microscopy (SEM). The contents of seven elements were analyzed quantitatively with electron probe microanalyzer (EPMA). The widths of the rod sections at the cervical enamels were larger than those at the cuspal enamels. The rod sections at the mesial cervical enamels in the incisors were more obscure and more decayed by acid solution than those in the premolars and molars. The calcium and phosphorus contents of the cervical enamels were significantly lower than those of the cuspal enamels. The carbon content of the cervical enamels was significantly higher than that of the cuspal enamels. The calcium and phosphorus contents of the cervical enamels were the significantly highest in the premolars. The carbon and sodium contents of the cervical enamels were significantly highest in the premolars. It is thought that the calcification level is lower, while the content of organic matter is higher at the cervical enamels than those at the cuspal enamels. It is considered that the sodium causes high calcification.     

H500型红外遥感定标高精度真空黑体辐射源的研制

对中国计量科学研究院研制的温度范围覆盖-93~220℃的H500型红外遥感定标高精度真空黑体辐射源进行了介绍。采用圆柱圆锥黑体腔和双层4段PID控温,在真空低背景(液氮冷却)环境下对该黑体进行了性能测试,在大气室温环境下,利用控制环境辐射反射比发射率测量方法测量了黑体空腔发射率和利用红外标准辐射温度计测量空腔底部温度均匀性等指标。实验结果表明,该黑体辐射源升温速率为1℃/min下,控制到温度点的稳定时间优于50 min,并且10 min内的温度稳定性在0.01℃以内;黑体温度设置在20℃、30℃和50℃下空腔发射率的测量结果分别为0.9965、0.9966和0.9963;其黑体底部温度均匀性优于0.03℃;在整个温度区域内扩展不确定度优于0.1℃(k=2)。     

Accurate determination of the mean relative humidity in controlled climates at high humidities (new method)

The measurement of the relative humidity (RH) at high levels to the desired accuracy is still a problem, especially for levels above 90% RH. The reasons for this are:

• i The accuracy of the standard apparatus is lower at high RH than at moderate and low RH;
• ii The need for accurate measurement of the RH in moisture controlled rooms is greater at high RH than at lower RH, because for moisture sensitive products, such as fibreboard boxes and certain horticultural products, the influence of a minor deviation in RH on the properties of these products is considerably greater at high RH than at moderate and low RH.

     

Difference of histology and elemental composition of the cervical enamels among human permanent teeth

The purpose of this study is to clarify the difference of histology and elemental composition of the cervical enamels among the human permanent teeth. The re-ground surfaces at the cervical enamels of them were observed under scanning electron microscopy (SEM). The contents of seven elements were analyzed quantitatively with electron probe microanalyzer (EPMA). The widths of the rod sections at the cervical enamels were larger than those at the cuspal enamels. The rod sections at the mesial cervical enamels in the incisors were more obscure and more decayed by acid solution than those in the premolars and molars. The calcium and phosphorus contents of the cervical enamels were significantly lower than those of the cuspal enamels. The carbon content of the cervical enamels was significantly higher than that of the cuspal enamels. The calcium and phosphorus contents of the cervical enamels were the significantly highest in the premolars. The carbon and sodium contents of the cervical enamels were significantly highest in the premolars. It is thought that the calcification level is lower, while the content of organic matter is higher at the cervical enamels than those at the cuspal enamels. It is considered that the sodium causes high calcification.     

Optical-disk media fabrication for high data-transfer rate

Two media fabrication methods are developed in order to improve the data-transfer rate of optical disks. One is a beam-scanning method for multispiral pregroove recording. A sixfold spiral pregroove with a 1.6-μm spacing can be recorded with this method. The other is a method for fabrication of phase-change optical-disk media that provides signal reading at 670 nm, writing at 830 nm, and high erasability at high linear velocity. The linear recording density of disks fabricated in this way is 1.2 times higher than that of optical disks read at 830 nm, and the erasability is more than 25 dB at 40 m/s. These methods offer the possibility of a data transfer rate 10 times higher than with conventional methods.     

NLG型桥塞火药的耐热性和燃烧稳定性研究

采用DTA、TGA、定容燃烧试验和电缆桥塞地面试验等方法,研究了NLG型桥塞火药的耐热性及其常、高温燃烧稳定性。结果表明：NLG型桥塞火药的耐热温度在250℃以上;120℃高温定容燃烧时,NLG型桥塞装药的燃气生成速率在28.0MPa压力以上时快于常温,燃烧稳定;在电缆桥塞坐封工具中变容燃烧时,NLG型桥塞装药燃烧稳定,压力上升曲线与常温时基本一致,最大压力平均值比常温高出2.5MPa。     

上海光源实验大厅地基振动规律及相干性分析

利用高灵敏度速度传感器,对上海光源实验大厅地基的随机振动进行了多点同步测量。数据分析结果表明上海光源实验大厅地基随机振动幅值具有周期变化的规律,且在低频区2 Hz~10 Hz具有较好的隔振效果。首次在上海光源大厅内进行随机振动中传递的相干规律的测试,测试表明在上海光源实验大厅中,距离为10 m的测试点在2.5 Hz以内的随机振动的互相关大于0.9;距离超过10 m时,两点随机偏差大于50 nm,超过随机振动RMS振幅的20%。随机振动传递规律的分析,对同步辐射光学元件的隔振设计有一定的指导作用。     

Primary particle movement and change of property of cast iron by centrifugal effect in semi-solid processing

The particle distribution in semi-solid slurry under centrifugal field was simulated and the main factors such as fraction of solid, rotation speed, and holding time effecting the particle distributions are discussed. The simulation results showed that primary particles rich zone is produced in radially outer area and these results are in good agreement with the experiment. The centrifugal effect produces the primary particles distribution along the radial direction. Denser particles are concentrated in outside than inner side. For high fraction of solid samples, ‘wall’ appear in the middle of samples because of high viscosity region making particle difficult to move. Longer holding time gives denser primary particles concentrated more in outside than inner side. Higher rotation speed gives increased gradient of hardness in the radial direction. It is due to that number of primary austenite at inner side at higher rotation speed is less than that at lower rotation one. At higher rotation speed, ledeburite forms more at inner side of specimen than at the other one. It is also shown that semi-solid processing at lower fraction of solid gives higher hardness because smaller number of primary austenite, namely more ledeburite forms in microstructure. The present study gives useful information on producing material with locally changing property by semi-solid processing.     

Cryogenic system of the MAX-Wiggler

A novel insertion device for electron storage rings called the MAX-Wiggler has been constructed and commissioned at MAX-lab. The MAX-Wiggler is a cold bore superconducting wiggler magnet with 47 3.5 T poles and a period length of 61 mm aimed for the production of X-rays at the 1.5 GeV electron storage ring MAX-II at MAX-lab. This note describes the cryogenic system of the MAX-Wiggler, theoretical predictions of the heat loads to the cryostat, and measured heat loads at operation. The cryostat is a helium cooled bath type cryostat. The design criterion for the cryostat was to have a liquid He boil-off less than 3 l/h, which corresponds to a heat load of 2.1 W. The theoretical calculations predicted a heat load of 0.87 W to the liquid He bath. Of the 0.87 W predicted heat load, 0.17 W was predicted to be induced by the stored beam in MAX-II, 0.12 W from synchrotron radiation and 0.05 W from image currents. The measured heat load to the liquid He bath is larger than predicted from the theoretical calculations and at nominal working conditions it is 1.7 W. The measured contribution to the total heat load from the stored beam of 200 mA in MAX-II is 0.86 W, 0.59 W from image currents and 0.26 W from synchrotron radiation. The measured contribution from the image current is 0.59 W, about 10 times larger than expected from the theoretical calculations, which is assumed to depend on that the Cu plating of the inner surfaces of the cold bore has a lower electrical conductivity than foreseen. The higher than expected heat load from synchrotron radiation is assumed to come from a positioning error of the upstream absorber for synchrotron radiation. There is no observable increase of the heat load with the wiggler at full field. Even though the heat loads are higher than expected, the design criterion of obtaining a cryostat with a liquid He boil-off inferior to 3 l/h with 200 mA of stored current in MAX-II has been met.     

国产CCF300/双马树脂层合板高温拉伸与压缩性能试验研究

对碳纤维(CCF300)/双马树脂(GW-300)复合材料层合板进行了200 ℃和300 ℃高温环境下的拉伸和压缩性能试验, 研究其在不同温度环境下基本力学性能的变化。研究结果表明, 由基体控制试件在高温下的拉伸强度和模量比由纤维控制试件降低的比例大; 随着温度的升高, 厚试件的压缩强度比薄试件的压缩强度提高幅度明显; 高温下, 拉伸性能保持率较高, 而压缩性能保持率较低; 300 ℃下基体控制试件和纤维控制试件的拉伸强度保持率分别达70%以上和90%以上, 而厚试件和薄试件的压缩强度保持率都只略高于30%。