全文获取类型
收费全文 | 53篇 |
免费 | 20篇 |
国内免费 | 39篇 |
专业分类
化学 | 36篇 |
晶体学 | 1篇 |
综合类 | 2篇 |
数学 | 2篇 |
物理学 | 23篇 |
无线电 | 48篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 7篇 |
2012年 | 11篇 |
2011年 | 5篇 |
2010年 | 5篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 11篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 3篇 |
排序方式: 共有112条查询结果,搜索用时 31 毫秒
31.
催化剂对煤着火特性的影响 Ⅱ.不同催化剂对煤催化着火的影响 总被引:10,自引:2,他引:8
通过测定煤的着火点研究了不同催化剂对大同烟煤和晋城无烟煤的催化着火的影响。结果表明,催化剂化学组成是决定催化作用大小的一个重要的因素,具有同一碱金属离子,不同阴离子的催化剂酸性越强,催化作用越弱,其催化活性顺序为OH~->CO_3~(2-)>Cl~->SO_4~(2-);具有同一阴离子,不同碱金属或碱土金属阳离子的催化作用可用“电子转移学说”来解释,其催化作用的大小,随相应的碱金属,碱土金属的第一电离能的减少而增加。 相似文献
32.
A specially designed experiment is performed for investigating gate-induced
drain leakage (GIDL) current in 90nm CMOS technology using lightly-doped
drain (LDD) NMOSFET. This paper shows that the drain bias $V_{\rm D}$ has a
strong effect on GIDL current as compared with the gate bias $V_{\rm G}$ at the
same drain--gate voltage $V_{\rm DG}$. It is found that the difference between
$I_{\rm D}$ in the off-state $I_{\rm D}-V_{\rm G}$ characteristics and the
corresponding one in the off-state $I_{\rm D}-V_{\rm D}$ characteristics, which is
defined as $I_{\rm DIFF}$, versus $V_{\rm DG}$ shows a peak. The difference between
the influences of $V_{\rm D}$ and $V_{\rm G}$ on GIDL current is shown
quantitatively by $I_{\rm DIFF}$, especially in 90nm scale. The difference is
due to different hole tunnellings. Furthermore, the maximum $I_{\rm DIFF
}$($I_{\rm DIFF,MAX})$ varies linearly with $V_{\rm DG}$ in logarithmic coordinates
and also $V_{\rm DG}$ at $I_{\rm DIFF,MAX}$ with $V_{\rm F}$ which is the characteristic
voltage of $I_{\rm DIFF}$. The relations are studied and some related
expressions are given. 相似文献
33.
Comparison of hot-hole injections in ultrashort channel LDD nMOSFETs with ultrathin oxide under an alternating stress 下载免费PDF全文
The behaviours of three types of hot-hole injections in ultrashort
channel lightly doped drain (LDD) nMOSFETs with ultrathin oxide
under an alternating stress have been compared. The three types of
hot-hole injections, i.e. low gate voltage hot hole injection
(LGVHHI), gate-induced drain leakage induced hot-hole injection
(GIDLIHHI) and substrate hot-hole injection (SHHI), have different
influences on the devices damaged already by the previous hot
electron injection (HEI) because of the different locations of
trapping holes and interface states induced by the three types of
injections, i.e. three types of stresses. Experimental results show
that GIDLIHHI and LGVHHI cannot recover the degradation of electron
trapping, but SHHI can. Although SHHI can recover the device's
performance, the recovery is slight and reaches saturation quickly,
which is suggested here to be attributed to the fact that trapped
holes are too few and the equilibrium is reached between the
trapping and releasing of holes which can be set up quickly in the
ultrathin oxide. 相似文献
34.
针对目前商用软件在CAD/CAPP/CAM(简称3C)集成开发上存在的问题,对3C集成的方式和关键技术进行了初步的分析。 相似文献
35.
研究了反向衬底偏压VB下纳米N沟道金属氧化物半导体场效应晶体管中栅调制界面产生(GMG)电流IGMG特性, 发现IGMG曲线的上升沿与下降沿随着|VB|的增大向右漂移. 基于实验和理论模型分析, 得出了VB与这种漂移之间的物理作用机制, 漂移现象的产生归因于衬底偏压VB 调节了表面电势φs在栅电压VG 中的占有比重: |VB|增大时相同VG下φs会变小, φs 的变化继而引发上升沿产生率因子gr减小以及下降沿产生率因子gf增大. 进一步发现IGMG 上升沿与下降沿的最大跨导GMR, GMF 在对数坐标系下与VB成线性关系, 并且随着|VB|增加而增大. 由于漏电压VD在IGMG 上升沿与下降沿中的作用不同, 三种VD下GMR-VB曲线重合而GMF-VB曲线则产生差异. 增大VD 会增强gf 随VG的变化, 因此使得给定VB 下的GMF变大. 同时这却导致了更大VD下GMF-VB 曲线变化的趋势减缓, 随着VD从0.2 V变为0.6 V, 曲线的斜率s从0.09减小到0.03.
关键词:
产生电流
表面势
衬底偏压
N沟道金属氧化物半导体场效应晶体管 相似文献
36.
本文研究了90nm CMOS工艺下栅氧化层厚度为1.4 nm沟道长度为100 nm的轻掺杂漏(LDD)nMOSFET栅电压VG对栅致漏极泄漏 (GIDL)电流Id的影响,发现不同VG下ln (Id/(VDG-1.2))-1/(VDG-1.2)曲线相比大尺寸厚栅器件时发生了分裂现象. 通过比较VG变化下ln(Id/(VDG-1.2))的差值,得出VG与这种分裂现象之间的作用机理,分裂现象的产生归因于VG的改变影响了GIDL电流横向空穴隧穿部分所致. 随着|VG|的变小,ln(Id/(VDG-1.2))曲线的斜率的绝对值变小.进一步发现不同VG对应的ln (Id/(VDG-1.2))曲线的斜率c及截距d与VG呈线性关系,c,d曲线的斜率分别为3.09和-0.77. c与d定量的体现了超薄栅超短沟器件中VG对GIDL电流的影响,基于此,提出了一个引入VG 影响的新GIDL电流关系式. 相似文献
37.
影响靶材刻蚀特性的主要因素来自平行靶面的磁场分布,为了得到更优的磁控靶结构参数以实现靶面水平磁感应强度的均匀分布,本文利用Comsol软件对双环磁控溅射靶的靶面水平磁感应强度分布进行模拟分析,得出了当内磁环高度h=10 mm,外磁环与靶材间距d=7 mm时的靶面水平磁感应强度分布较为理想.除此之外,还探讨了加装导磁片对靶面水平磁感应强度的影响,结果表明采用适当的导磁片长度、厚度以及导磁片与磁环之间的间距,对靶材的水平磁场强度分布具有调节作用.在工程应用中,技术人员可以事先对靶材结构进行模拟优化以节省生产周期和成本,对实际生产具有指导意义. 相似文献
38.
We analyze the failure mechanism of W-plug via electromigration made in a 0.5-μm CMOS SPTM process. Failure occurs at the top or bottom of a W-plug via. We design a series of via chains, whose size ranges from 0.35 to 0.55μm. The structure for the via electromigration test is a long via chain, and the layer in the via is Ti/TiN/W/TiN. Using a self-heated resistor to raise the temperature of the via chain allows the structure to be stressed at lower current densities, which does not cause significant joule heating in the plugs. This reduces the interaction between the plug and the plug contact resistance and the time-to-failure for the via chain. The lifetime of a W-plug via electromigration is on the order of 3×10^7S, i.e., far below the lifetime of metal electromigration. The study on W-plug via electromigraion in this paper is beneficial for wafer level reliability monitoring of the ultra-deep submicron CMOS multilayer metal interconnect process. 相似文献
39.
40.
Hot-carrier degradation for 90nm gate length LDD-NMOSFET with ultra-thin gate oxide under low gate voltage stress 下载免费PDF全文
The hot-carrier degradation for 90~nm gate length lightly-doped drain
(LDD) NMOSFET with ultra-thin (1.4~nm) gate oxide under the low gate
voltage (LGV) (at Vg=Vth, where Vth is the
threshold voltage) stress has been investigated. It is found that the
drain current decreases and the threshold voltage increases after the
LGV (Vg=Vth stress. The results are opposite to the
degradation phenomena of conventional NMOSFET for the case of this
stress. By analysing the gate-induced drain leakage (GIDL) current
before and after stresses, it is confirmed that under the LGV stress
in ultra-short gate LDD-NMOSFET with ultra-thin gate oxide, the hot
holes are trapped at interface in the LDD region and cannot shorten
the channel to mask the influence of interface states as those in
conventional
NMOSFET do, which leads to the different degradation phenomena from those of the
conventional NMOS devices. This paper also discusses the degradation in the
90~nm gate length LDD-NMOSFET with 1.4~nm gate oxide under the LGV stress at
Vg=Vth with various drain biases. Experimental results show that
the degradation slopes (n) range from 0.21 to 0.41. The value of
n is
less than that of conventional MOSFET (0.5-0.6) and also that of the long gate
length LDD MOSFET (\sim0.8). 相似文献