期刊文献+
共找到43篇文章
< 1 2 3 >
每页显示 20 50 100
虚像总是正立的吗
1
作者 高雄武 李美娇 《物理教学探讨》 2023年第4期55-56,共2页
“平面镜成虚像,而虚像一定是正立的”这种普遍存在于广大物理教师和教学资料、教学视频中的观点是经不起推敲的。平面镜成像特征就是像与物体关于镜面立体对称,并无正立一说;要确定像的正、倒,必须先确定物体的方向,再根据像的方向与... “平面镜成虚像,而虚像一定是正立的”这种普遍存在于广大物理教师和教学资料、教学视频中的观点是经不起推敲的。平面镜成像特征就是像与物体关于镜面立体对称,并无正立一说;要确定像的正、倒,必须先确定物体的方向,再根据像的方向与物体的方向是否保持一致来确定像是否正立。 展开更多
关键词 平面镜成像 正立 体对称
下载PDF
正立电器公司知识型员工流失问题研究
2
作者 侯正喜 《中国市场》 2010年第48期59-59,共1页
以笔者所经营的正立电器公司为个案,针对其近年来知识型员工流失严重的情况,通过实地调研,并在定量分析的基础上进行定性研究,具体采用问卷调查法和访谈法,探询本企业知识型员工流失的原因,并提出相应的对策。
关键词 正立电器 知识型员工 员工流失 全面报酬
下载PDF
冷凝器正立与倒立布置的外盘微通道热泵热水器对比研究 被引量:1
3
作者 施永康 杨庆成 +1 位作者 丁小江 卢淑霞 《广东化工》 CAS 2017年第18期156-158,共3页
为了探究冷凝器布置方式对外盘微通道热泵热水器性能的影响,对冷凝器采用正立布置方式和倒立布置方式的热泵热水器进行了对比实验研究。结果表明,在运行过程中,冷凝器采用倒立布置的系统的被加热水温度均匀性更好;而在名义实验工况下,... 为了探究冷凝器布置方式对外盘微通道热泵热水器性能的影响,对冷凝器采用正立布置方式和倒立布置方式的热泵热水器进行了对比实验研究。结果表明,在运行过程中,冷凝器采用倒立布置的系统的被加热水温度均匀性更好;而在名义实验工况下,冷凝器采用正立布置的系统的制热量和COP较倒立布置系统有明显地提高,同时其冷凝器压降也有所降低。 展开更多
关键词 冷凝器 正立 微通道 热泵热水器
下载PDF
海市蜃楼的映像是正立还是倒立的? 被引量:1
4
作者 沈启正 《物理教师(高中版)》 2001年第11期26-26,28,共2页
关键词 海市蜃楼 映像 正立 高中 物理教学 大气光学 全反射
原文传递
环境群体性事件的后控:发挥“正范立行”的核心作用 被引量:1
5
作者 程启军 《理论导刊》 北大核心 2017年第8期28-31,共4页
当前,无论是在既成污染型环境群体性事件,还是预防风险型环境群体性事件中,对于事件的控制和应对,基层政府都在不同程度上表现出"被动性"和"人为性"。为此,当务之急是通过规范政府的行动立场,规范政府的生态补偿行... 当前,无论是在既成污染型环境群体性事件,还是预防风险型环境群体性事件中,对于事件的控制和应对,基层政府都在不同程度上表现出"被动性"和"人为性"。为此,当务之急是通过规范政府的行动立场,规范政府的生态补偿行为及干预事件的行政行为,规范环境利益受损方的维权行动,规范传统媒体与新媒体的舆论行为等方式,形成控制环境群体性事件的"制度化"和"法制化"支撑。在环境群体性事件的后控中,应充分发挥"正范立行"的核心作用,避免环境群体性事件向暴力事件的演变,使对其控制尽可能地具有"可预期性"和"可调节性"。 展开更多
关键词 环境群体性事件 后控 行” 依法行政
下载PDF
久正胃立康治疗功能性消化不良85例 被引量:1
6
作者 姜小红 《江西中医药》 2010年第12期34-35,共2页
目的:观察久正胃立康治疗功能性消化不良的临床疗效。方法:选取门诊病例85例采用随机分组对照,分为治疗组45例和对照组40例;治疗组采用久正胃立康(陕西健民制药有限公司生产)治疗;对照组采用西药奥美拉唑(修正制药厂生产),吗丁啉(丽珠... 目的:观察久正胃立康治疗功能性消化不良的临床疗效。方法:选取门诊病例85例采用随机分组对照,分为治疗组45例和对照组40例;治疗组采用久正胃立康(陕西健民制药有限公司生产)治疗;对照组采用西药奥美拉唑(修正制药厂生产),吗丁啉(丽珠集团制药厂生产)治疗。结果:治疗组显效率44.4%、总有效率91.1%,未见明显不良不应;对照组显效率15%、总有效率62.5%。结论:久正胃立康治疗功能性消化不良疗效显著。 展开更多
关键词 中药制剂 功能性消化不良
下载PDF
浅谈弹簧测力计的倒立使用 被引量:2
7
作者 傅兰芳 陶复桂 《中国科教创新导刊》 2010年第9期91-92,共2页
这篇论文是在探究"使用定滑轮有什么好处"的课堂教学中所遇到的实际问题,通过认真、仔细的探究与分析,找到问题所在——弹簧测力计的倒立使用不正确,然后分析原因,使实验具有可行性、科学性。
关键词 弹簧测力计 正立 探究 原因 措施
下载PDF
面孔方位对返回抑制的影响 被引量:10
8
作者 王丽丽 罗跃嘉 +1 位作者 郭亚桥 张庆林 《心理科学》 CSSCI CSCD 北大核心 2010年第1期100-103,共4页
采用辨别任务探讨了正立与倒立的中性面孔线索对返回抑制的影响。实验一采用同时线索化范式考察了正立与倒立面孔线索对靶刺激反应的影响,结果发现,两种面孔线索对随后靶刺激的反应没有影响。实验二采用单线索范式考察正立与倒立面孔对... 采用辨别任务探讨了正立与倒立的中性面孔线索对返回抑制的影响。实验一采用同时线索化范式考察了正立与倒立面孔线索对靶刺激反应的影响,结果发现,两种面孔线索对随后靶刺激的反应没有影响。实验二采用单线索范式考察正立与倒立面孔对返回抑制的影响,结果发现,两种线索条件下均产生了返回抑制,而且返回抑制量没有显著差异。实验三,正立与倒立面孔作为靶刺激呈现,得到与实验二相同的结果。这些结果表明当采用中性面孔为线索时,返回抑制的产生并不受线索与靶刺激显著性的影响,而且返回抑制这种"盲目"机制不受任务难度的影响。 展开更多
关键词 返回抑制 正立面孔 面孔
下载PDF
面孔线索对返回抑制的影响 被引量:1
9
作者 王丽丽 郭亚桥 +3 位作者 邱江 袁加锦 刘晓 张庆林 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2008年第8期161-164,共4页
研究了考察正立面孔、倒立面孔与非面孔线索对返回抑制的影响,发现在三种线索条件下均产生了返回抑制,而且返回抑制量没有差异.结果表明:在定位任务中当采用中性面孔为线索时,返回抑制的产生并不受线索特征的影响,返回抑制是一种"... 研究了考察正立面孔、倒立面孔与非面孔线索对返回抑制的影响,发现在三种线索条件下均产生了返回抑制,而且返回抑制量没有差异.结果表明:在定位任务中当采用中性面孔为线索时,返回抑制的产生并不受线索特征的影响,返回抑制是一种"盲目"机制. 展开更多
关键词 返回抑制 正立面孔 面孔
下载PDF
从“体验感受”到“理论分析”:革新学生错误的前概念教学——以“平面镜成像”为例 被引量:1
10
作者 任少铎 《福建基础教育研究》 2019年第8期108-110,共3页
平面镜成像一节,由于学生已有的错误感性认识,错误的前概念会阻碍新知识的学习。通过巧妙处理图片,利用全新的现象带来的冲击,彻底革新学生错误的前概念,真正提升学生包含物理思维在内的物理学科核心素养。
关键词 平面镜成像 倒影 正立 视角不同 视觉震撼
下载PDF
Ultraviolet Source Assisted Enhancement of Attosecond Pulse 被引量:3
11
作者 冯立强 刘航 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2015年第1期21-26,I0001,共7页
A promising method to improve the attosecond pulse intensity has been theoretically pre- sented by properly adding an ultraviolet pulse into the orthogonal two-color field. The results show that by properly adding a 1... A promising method to improve the attosecond pulse intensity has been theoretically pre- sented by properly adding an ultraviolet pulse into the orthogonal two-color field. The results show that by properly adding a 125 nm ultraviolet pulse to the orthogonal two-color field, not only the harmonic yield is enhanced by 2 orders of magnitude compared with the original orthogonal two-color field case, but also the single short quantum path, which is selected to contribute to the harmonic spectrum, results in an ultrabroad 152 eV bandwidth. Moreover, by optimizing the laser parameters, we find that the harmonic enhancement is not very sen- sitive to the pulse duration and the polarized angle of the assisted ultraviolet pulse, which is much better for experimental realization. As a result, an isolated pulse with duration of 38 as can be obtained, which is 2 orders of magnitude improvement in comparison with the original two-color orthogonal field case. 展开更多
关键词 High-order harmonic generation Isolated pulse Two-color orthogonal field Ultraviolet source
下载PDF
Asymptotic Behavior and Nonexistence of Positive Solutions of Delay Difference Equations *L
12
作者 彭名书 徐千里 《Journal of Beijing Institute of Technology》 EI CAS 1999年第1期25-30,共6页
Aim To obtain new criteria for asymptotic behavior and nonexistence of positive solutions of nonlinear neutral delay difference equations. Methods By means of Hlder inequality and a method of direct analysis, some i... Aim To obtain new criteria for asymptotic behavior and nonexistence of positive solutions of nonlinear neutral delay difference equations. Methods By means of Hlder inequality and a method of direct analysis, some interesting Lemmas were offered. Results and Conclusion New criteria for asymptotic behavior and nonexistence of positive solutions of nonlinear neutral delay difference equations are established, which extend and improve the results obtained in the literature. Some interesting examples illustrating the importance of our results are also included. 展开更多
关键词 OSCILLATION asymptotic behavior positive solution neutral delay difference equation NONLINEARITY
下载PDF
一种有价文件抬头检测面向识别方法
13
作者 刘光禄 张守龙 段无悔 《中国科技期刊数据库 工业A》 2022年第5期287-291,共5页
纸质有价文件电子化存储的前提之一,需要先对有价文件进行光学扫描,得到影像信息并存储。为了保证存储的影像信息为正立,一般情况下,需要人为将有价文件按照扫描装置的要求,按序放入扫描。随着人工智能技术的高速发展及人们对智能化的要... 纸质有价文件电子化存储的前提之一,需要先对有价文件进行光学扫描,得到影像信息并存储。为了保证存储的影像信息为正立,一般情况下,需要人为将有价文件按照扫描装置的要求,按序放入扫描。随着人工智能技术的高速发展及人们对智能化的要求,传统的有价文件扫描影像效率及智能化有待提高。本文提出了一种有价文件抬头检测面向识别的方法,解决有价文件扫描需要人工按照扫描装置单一方向放入扫描的问题,可以按任意方向放入扫描,最终都会得到正立的文件影像信息,进而提升整个文件扫描系统的效率和鲁棒性。 展开更多
关键词 有价文件 光学扫描 抬头检测 面向识别 影像正立
下载PDF
Quasi-χ~2 Distribution and the Independence of Wishart Distribution
14
作者 朱道元 赵胜利 《Journal of Southeast University(English Edition)》 EI CAS 2002年第2期173-176,共4页
In this paper, the authors generalize the definition of χ 2 distribution and introduce a quasi χ 2 distribution, and then prove several properties of it, find the necessary and sufficient conditions of i... In this paper, the authors generalize the definition of χ 2 distribution and introduce a quasi χ 2 distribution, and then prove several properties of it, find the necessary and sufficient conditions of independence about multivariate normal distributions, matrix normal distributions and two parts of the Wishart distribution. 展开更多
关键词 quasi χ 2 Wishart distribution INDEPENDENCE
下载PDF
Surgical resection of a solitary para-aortic lymph node metastasis from hepatocellular carcinoma 被引量:3
15
作者 Junji Ueda Hiroshi Yoshida +9 位作者 Yasuhiro Mamada Nobuhiko Taniai Sho Mineta Masato Yoshioka Youichi Kawano Tetsuya Shimizu Etsuko Hara Chiaki Kawamoto Keiko Kaneko Eiji Uchida 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第23期3027-3031,共5页
Lymph node (LN) metastases from hepatocellular carcinoma (HCC) are considered uncommon. We describe the surgical resection of a solitary para-aortic LN metastasis from HCC. A 65-year-old Japanese man with B-type liver... Lymph node (LN) metastases from hepatocellular carcinoma (HCC) are considered uncommon. We describe the surgical resection of a solitary para-aortic LN metastasis from HCC. A 65-year-old Japanese man with B-type liver cirrhosis was admitted for the evaluation of a liver tumor. He had already undergone radiofrequency ablation, transcatheter arterial chemoembolization, and percutaneous ethanol injection therapy for HCC. Despite treatment, viable regions remained in segments 4 and 8. We performed a right paramedian sectionectomy with partial resection of the left paramedian section of the liver. Six months later, serum concentrations of alpha-fetoprotein (189 ng/mL) and PIVKA-2 (507 mAU/mL) increased. Enhanced com- puted tomography of the abdomen revealed a tumor (20 mm in diameter) on the right side of the abdominal aorta. Fluorine-18 fluorodeoxyglucose positron emission tomography revealed an increased standard uptake value. There was no evidence of recurrence in other regions. Esophagogastroduodenoscopy and colonoscopy revealed no malignant tumor in the gastrointestinal tract. Para-aortic LN metastasis from HCC was thus diagnosed. We performed lymphadenectomy. Histopathological examination revealed that the tumor was largely necrotic, with poorly differentiated HCC on its surface, which confirmed the suspected diagnosis. After 6 mo tumor marker levels were normal, with no evidence of recurrence. Our experience suggests that a solitary para-aortic LN metastasis from HCC can be treated surgically. 展开更多
关键词 Surgical resection Lymph node metasta-sis Hepatocellular carcinoma HEPATECTOMY Positronemission tomography
下载PDF
P-FFT and FG-FFT with real coefficients algorithm for the EFIE
16
作者 谢家烨 周后型 +3 位作者 牟星 华光 李卫东 洪伟 《Journal of Southeast University(English Edition)》 EI CAS 2014年第3期267-270,共4页
In order to reduce the storage amount for the sparse coefficient matrix in pre-corrected fast Fourier transform (P-FFT) or fitting the Green function fast Fourier transform (FG-FFT), the real coefficients are solv... In order to reduce the storage amount for the sparse coefficient matrix in pre-corrected fast Fourier transform (P-FFT) or fitting the Green function fast Fourier transform (FG-FFT), the real coefficients are solved by improving the solution method of the coefficient equations. The novel method in both P-FFT and FG-FFT for the electric field integral equation (EFIE) is employed. With the proposed method, the storage amount for the sparse coefficient matrix can be reduced to the same level as that in the adaptive integral method (AIM) or the integral equation fast Fourier transform (IE-FFT). Meanwhile, the new algorithms do not increase the number of the FFTs used in a matrix-vector product, and maintain almost the same level of accuracy as the original versions. Besides, in respect of the time cost in each iteration, the new algorithms have also the same level as AIM (or IE- FFF). The numerical examples demonstrate the advantages of the proposed method. 展开更多
关键词 real coefficients complex coefficients pre-corrected fast Fourier transform (P-FFT) fitting the Greenfunction fast Fourier transform (FG-FFT)
下载PDF
Multiple Positive Solutions for Some Neutral Integral Equatious Modeling Infectious Disease 被引量:1
17
作者 ZHAOHua-xiang SUNXing-wang 《Chinese Quarterly Journal of Mathematics》 CSCD 2003年第1期21-28,共8页
By using fixed point index theory of cone mapping and extension method, this paper discusses the existence of multiple positive solution of nonlinear neutral integral equatious modeling infectious disease.
关键词 neutral integral equation strict set contraction CONE
下载PDF
On the Existence of Positive Solutions for Impulsive Neutral Differential Equations
18
作者 何智敏 葛渭高 《Journal of Beijing Institute of Technology》 EI CAS 1999年第4期352-356,共5页
Aim To investigate the existence of positive solutions for impulsive neutral differential equations. Methods The Banach contraction principle was used to establish our results. Results and Conclusion The results of... Aim To investigate the existence of positive solutions for impulsive neutral differential equations. Methods The Banach contraction principle was used to establish our results. Results and Conclusion The results of the existence of positive solutions for impulsive neutral differential equations are obtained. 展开更多
关键词 impulsive neutral differential equation positive solution Banach contraction principle
下载PDF
On the Existence of Positive Solutions of Neutral Differential Equations
19
作者 李青阳 《Chinese Quarterly Journal of Mathematics》 CSCD 2002年第2期77-80,共4页
Consider the first order neutral delay differential equation with positive and negative coefficients:[x(t)-c(t)x(t-γ)]+p(t)x(t-τ)-Q(t)x(t-δ)=0,t≥t 0,(1)where c,p,Q∈C((t 0,∞),R +),R +=(0,∞),γ】0,t】δ≥0. W... Consider the first order neutral delay differential equation with positive and negative coefficients:[x(t)-c(t)x(t-γ)]+p(t)x(t-τ)-Q(t)x(t-δ)=0,t≥t 0,(1)where c,p,Q∈C((t 0,∞),R +),R +=(0,∞),γ】0,t】δ≥0. We obtain the sufficient condition for the existence of positive solutions of Eq.(1). As a corollary, we improve the correspondent result in by removing the condition∫ ∞ c 0 (t) d t=∞,where (t)=p(t)-Q(t-τ+δ)≥0. 展开更多
关键词 positive solution neutral different equation OSCILLATION
下载PDF
New Multiple Soliton-like and Periodic Solutions for (2+l)-Dimensional Canonical Generalized KP Equation with Variable Coefficients 被引量:3
20
作者 ZHANG Li-Hua LIU Xi-Qiang BAI Cheng-Lin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第5X期793-798,共6页
In this paper, the generalized ranch function method is extended to (2+1)-dimensianal canonical generalized KP (CGKP) equation with variable coetfficients. Taking advantage of the Riccati equation, many explicit ... In this paper, the generalized ranch function method is extended to (2+1)-dimensianal canonical generalized KP (CGKP) equation with variable coetfficients. Taking advantage of the Riccati equation, many explicit exact solutions, which contain multiple soliton-like and periodic solutions, are obtained for the (2+1)-dimensional OGKP equation with variable coetffcients. 展开更多
关键词 (2+1)-dimensional canonical generalized (CGKP) equation with variable coefficients tanh function method Riccati equation soliton-like and periodic solutions
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部