HHD型核子秤电离室物理性能检测

HHD型核子秤电离室已成功地使用于HCS型核子秤.对它的各种物理性能指标进行了检测,各项性能指标都达到了设计要求。     

日本水土保持见闻

通过考察日本的水土保持工作,文中在简明介绍日本水土保持工作的基础上,尤其着重介绍了日本的庭园水土保持,小流域的综合治理,治山绿化工程,水土保持科学研究和滑坡、泥石流防治工程等技术措施和方法。并提出了一些有益的建议;他们的经验有许多值得我们借鉴。     

黑钨矿细泥浮选时有机螯合剂的活化作用

黑钨矿细泥的有效浮选仍是有待解决的选矿难题。本文试图采用有机螯合剂作活化剂，以实现黑钨细泥浮选药剂低耗高效的目的。     

高质量的一级光栅1．55μmDFB激光器

本文详细叙述了ＤＦＢ激光器的设计要点和新的工艺。采用一级全息光栅和二步液相外延法批量研制出高稳定单纵模工作的１．５５μｍ分布反馈激光器（ＤＦＢ—ＬＤ）。外延片成品率＞４０％。器件特性：２５℃时阈值电流２０ｍＡ，单面光功率＞１０ｍｗ，主边模抑制比ＳＭＳＲ达４３ｄＢ（λ／４相移光栅），谱线宽度△ν－２０ｄＢ＝０．３ｎｍ，调制速率＞１．８ＧＨｚ。可靠性测试显示：高温监测光谱稳定，２５°Ｃ时阈值退化率△Ｉｔｈ／ｔ＜０．３ｍＡ／ｋｈ，对应器件预估寿命将超过１０万ｈ。     

An error and sensitivity analysis of the atmospheric- andsoil-correcting variants of the NDVI for the MODIS-EOS

Several soil- and atmospheric-correcting variants of the normalized difference vegetation index (NDVI) have been proposed to improve the accuracy in estimating biophysical plant parameters. In this study, a sensitivity analysis, utilizing simulated model data, was conducted on the NDVI and variants by analyzing the atmospheric- and soil-perturbed responses as a continuous function of leaf area index. Percent relative error and vegetation equivalent “noise” (VEN) were calculated for soil and atmospheric influences, separately and combined. The NDVI variants included the soil-adjusted vegetation index (SAVI), the atmospherically resistant vegetation index (ARVI), the soil-adjusted and atmospherically resistant vegetation index (SARVI), the modified SAVI (MSAVI), and modified SARVI (MSARVI). Soil and atmospheric error were of similar magnitudes, but varied with the vegetation index. All new variants outperformed the NDVI. The atmospherically resistant versions minimized atmospheric noise, but enhanced soil noise, while the soil adjusted variants minimized soil noise, but remained sensitive to the atmosphere. The SARVI, which had both a soil and atmosphere calibration term, performed the best with a relative error of 10 percent and VEN of ±0.33 LAI. By contrast, the NDM had a relative error of 20 percent and VEN of ±0.97 LAI     

Suppression of boron penetration in p+ polysilicon gateP-MOSFETs using low-temperature gate-oxide N2O anneal

It has been reported that high-temperature (~1100°C) N₂ O-annealed oxide can block boron penetration from poly-Si gates to the silicon substrate. However, this high-temperature step may be inappropriate for the low thermal budgets required of deep-submicron ULSI MOSFETs. Low-temperature (900~950°C) N₂O-annealed gate oxide is also a good barrier to boron penetration. For the first time, the change in channel doping profile due to compensation of arsenic and boron ionized impurities was resolved using MOS C-V measurement techniques. It was found that the higher the nitrogen concentration incorporated at Si/SiO₂ interface, the more effective is the suppression of boron penetration. The experimental results also suggest that, for 60~110 Å gate oxides, a certain amount of nitrogen (~2.2%) incorporated near the Si/SiO₂ interface is essential to effectively prevent boron diffusing into the underlying silicon substrate