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21.
ICP-MS/ICP-AES法分析成年男性血清中18种元素含量参照值   总被引:5,自引:1,他引:5  
运用ICP-MS和ICP-AES法同时分析丹东某硼矿周围人群血清中18种元素的含量水平。样品经过双氧水-纯化硝酸体系消解,采用稀释分析及双内标铑(Rh)和铼(Re)进行校正。该法最低检出限能满足血清样品的分析要求,多数元素回收率在95%~120%之间,相对标准偏差(RSD)在2.9%~10.8%之间。按照95%置信区间进行数据筛选,选出125人的数据统计分析,并与国内外其它研究结果进行比较。结果表明,采用该方法对血清中元素的分析结果可以作为当地成年男性血清中元素含量的参照值。  相似文献   
22.
We present the experimental results that demonstrate the enhancement of the short-circuit current of quantum well solar cells. The spectral response shows that the introduction of quantum wells extends the absorption spectrum of solar cells. The current densities under different truncated spectrums significantly increase, showing that quantum well solar cells are suitable to be the middle cells of GalnP/GaAs/Ge triple-junction solar cells to increase their overall conversion efficiency.  相似文献   
23.
A study on the single event transient (SET) induced by a pulsed laser in a silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) is presented in this work. The impacts of laser energy and collector load resistance on the SET are investigated in detail. The waveform, amplitude, and width of the SET pulse as well as collected charge are used to characterize the SET response. The experimental results are discussed in detail and it is demonstrated that the laser energy and load resistance significantly affect the SET in the SiGe HBT. Furthermore, the underlying physical mechanisms are analyzed and investigated, and a near-ideal exponential model is proposed for the first time to describe the discharge of laser-induced electrons via collector resistance to collector supply when both base-collector and collector-substrate junctions are reverse biased or weakly forward biased. Besides, it is found that an additional multi-path discharge would play an important role in the SET once the base-collector and collector-substrate junctions get strongly forward biased due to a strong transient step charge by the laser pulse.  相似文献   
24.
宝石  许军 《应用声学》2017,25(8):6-6
在模拟电路故障诊断中,故障特征的提取是一个非常重要的环节,其提取结果的好坏将直接影响最终的诊断正确率。对现有文献研究发现,每种特征提取方法单独使用时都有一定的局限性,为了能够更加充分的提取模拟电路故障特征,提出了小波包分析与主元分析并行应用的方法,并将两种方法提取的特征向量依据不同规则进行了三种类型的融合,方便对比实验。为获取最优小波特征,提出了特征偏离度,并以此为标准选择最优小波基。最后,通过设计一种改进的神经网络分类器模型,将融合后的三种特征向量送入其中进行仿真验证,得出最终诊断结果。结果表明,该方法能够有效克服单一特征提取方法提取不充分的缺点,提高故障诊断的正确率,并且融合因子 适中时诊断正确率最高。  相似文献   
25.
Stacked ruthenium (Ru) nanocrystals (NCs) are formed by rapid thermal annealing for the whole gate stacks and embedded in memory structure, which is compatible with conventional CMOS technology. Ru NCs with high density (3 × 10^12 cm-2), small size (2 4nm) and good uniformity both in aerial distribution and morphology are formed. Attributed to the higher surface trap density, a memory window of 5.2 V is obtained with stacked Ru NCs in comparison to that of 3.5 V with single-layer samples. The stacked Ru NCs device also exhibits much better retention performance because of Coulomb blockade and vertical uniformity between stacked Ru NCs.  相似文献   
26.
我院对门诊50例多次行鼓膜穿刺未见好转的慢性分泌性中耳炎患者作了鼓膜置管术,观察了术后自觉症状减轻又听力恢复等情况,取得了较好疗效.1临床资料 50例中男20例,女30例,年龄22~84岁,其中病程最短为3周,最长为10余年,6个月以下为35例占70%,6个月以上为25例,占30%. (1)临床表现:患者的主要症状为耳闷、耳鸣和听力下降,50例病人中,40例有鼻塞,5例患者伴有打喷嚏、流清涕等症状. (2)术前检查鼓膜明显内陷者40例,50例病人都经过2次以上鼓膜穿刺,且都穿刺出鼓室积液,50例病…  相似文献   
27.
1一般资料 本组6例中,男 4例,女2例,年龄13~67岁,平均 50岁,病程20d~14年不等,平均为4年.临床表现:头痛5例,视力下降3例,失明2例,复视1例,上睑下垂1例,眼球外展受限1例,鼻阻2例,流涕3例.本组病例行CT扫描4例,MRI检查3例,蝶窦诊断性穿刺2例,每例均行鼻内窥镜检查.本组病例均经手术治疗,术后病理检查结果,粘液囊肿5例,脓囊肿1例.2手术方法 手术进路包括筛窦进路5例(鼻外筛窦进路1例,鼻内筛窦经路4例),经腭部进路1例,现主要讲述内窥镜下鼻内蝶窦开放术.手术时,患者取…  相似文献   
28.
Interfacial and electrical properties of HfA10/GaSb metal-oxide-semiconductor capacitors (MOSCAPs) with sulfur passivation were investigated and the chemical mechanisms of the sulfur passivation process were carefully studied. It was shown that the sulfur passivation treatment could reduce the interface trap density Dit of the HfAIO/GaSb interface by 35% and reduce the equivalent oxide thickness (EOT) from 8 nm to 4 nm. The improved properties are due to the removal of the native oxide layer, as was proven by x-ray photoelectron spectroscopy measurements and high-resolution cross-sectional transmission electron microscopy (HRXTEM) results. It was also found that GaSb-based MOSCAPs with HfA10 gate dielectrics have interfacial properties superior to those using HfO2 or A1203 dielectric layers.  相似文献   
29.
邓勇  张喧轩  罗召洋  许军  杨孝全  孟远征  龚辉  骆清铭 《物理学报》2013,62(1):14202-014202
扩散光学断层成像作为一种无辐射损伤、低成本的光学在体成像技术,有着良好的应用前景,但具有空间分辨率低、难以定量的缺陷.为了提高扩散光学断层成像的分辨率,实现光学参数分布的精确重建,基于有限元方法,提出了融合结构先验信息的稳态扩散光学断层成像重建算法.该算法以扩散近似作为成像模型,通过软先验的Laplace 正则化方法引入由MicroCT提供的空间结构信息.采用伴随法计算Jacobian矩阵,Levenberg-Marquardt方法用来进行迭代优化.仿真结果表明该算法不仅能获得精确的光学参数值分布,而且显著地提高了迭代收敛的速度.  相似文献   
30.
陈燕文  谭桢  赵连锋  王敬  刘易周  司晨  袁方  段文晖  许军 《中国物理 B》2016,25(3):38504-038504
Various biaxial compressive strained GaSb p-channel metal–oxide–semiconductor field-effect transistors(MOSFETs)are experimentally and theoretically investigated. The biaxial compressive strained GaSb MOSFETs show a high peak mobility of 638 cm~2/V·s, which is 3.86 times of the extracted mobility of the fabricated GaSb MOSFETs without strain.Meanwhile, first principles calculations show that the hole effective mass of Ga Sb depends on the biaxial compressive strain.The biaxial compressive strain brings a remarkable enhancement of the hole mobility caused by a significant reduction in the hole effective mass due to the modulation of the valence bands.  相似文献   
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