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飘移学校
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作者 李化 《小学时代》 2009年第6期40-43,共4页
让唐东最担心的事情发生了:唐西的黑眼珠消失了!
关键词 《飘移学校》 李化 文学 散文
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飘移学校①
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作者 李化 《小学时代》 2009年第1期40-43,共4页
男生唐西和女生丁若若家住隔壁——一座大厦的32层。这天晚上,他们看到自己的学校连根拔起,飞到空中,飘移到他们的窗下……怎么会发生这样怪异的事情呢?不权如此,在他们的身边,一件惊心动魄的事情接踵而来……
关键词 小学 课外阅读 教材 教学方法 《飘移学校1》
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飘移学校(8)
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作者 李化 《小学时代》 2009年第8期40-43,共4页
7个人把当时的“噩梦”又都说了一遍,虽然还有后怕,可是他们一起发现了一个事情:梦里没有彭克!为什么?彭克到底是什么人?他为什么要这样做呢?
关键词 《飘移学校》 小学 作文 语文教学
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飘移学校(4)
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作者 李化 《小学时代》 2009年第4期40-43,共4页
第二天清晨,唐西和丁若若在校门口看到了看门的王大爷。原来,王大爷家的猫生了小猫,夜里11点多王大爷就回家照顾小猫去了,直到凌晨4点多才回来。看来王大爷并不知道昨晚学校发生的事情。太奇怪了,学校和以前没有什么两样,地面上... 第二天清晨,唐西和丁若若在校门口看到了看门的王大爷。原来,王大爷家的猫生了小猫,夜里11点多王大爷就回家照顾小猫去了,直到凌晨4点多才回来。看来王大爷并不知道昨晚学校发生的事情。太奇怪了,学校和以前没有什么两样,地面上连一丝缝隙都没有。那么学校昨天是怎么飞到空中的? 展开更多
关键词 小学 课外阅读 《飘移学校》 阅读材料
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The Driftless Electromigration Theory(Diffusion-Generation-Recombination-Trapping Theory) 被引量:4
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作者 薩支唐 揭斌斌 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第5期815-821,共7页
Electromigration is the transport of atoms in metal conductors at high electronic current-densities which creates voids in the conductors and increases the conductors' electrical resistance. It was delineated in 1961... Electromigration is the transport of atoms in metal conductors at high electronic current-densities which creates voids in the conductors and increases the conductors' electrical resistance. It was delineated in 1961 by Huntington; then modeled by the empirical electrical resistance formula derived by Black in 1969 to fit the dependences of the experimental electrical resistance and failure data on the electrical current density and temperature. Tan in 2007 reviewed 40-years' ap- plications of the empirical Black formula to conductor lines interconnecting transistors and other devices in silicon integrated circuits. Since the first Landauer theory in 1957,theorists have attempted for 50 years to justify the drift force or electron momentum transfer assumed by Black as some electron-wind force to impart on the metal atoms and ions to move them. Landauer concluded in 1989 that the electron wind force is untenable even considering the most fundamental and complete many-body quantum transport theory. A driftless or electron-windless atomic void model for metal conductor lines is reviewed in this article. It was developed in the mid-1980 and described in 1996 by Sah in a homework solution. This model accounts for all the current and temperature dependences of experimental resistance data fitted to the empiri- cal Black formula. Exact analytical solutions were obtained for the metal conductor line resistance or current, R (t)/R (0) = J(t)/J(0) = [1-2(t/τα)^1/α]^-1/2 ,in the bond-breaking limit with α = 1 to 2 and diffusion limit with α = 2 to 4,from low to high current densities, where τα is the characteristic time constant of the mechanism, containing bond breaking and diffusion rates and activation energies of the metal. 展开更多
关键词 ELECTROMIGRATION driftless void model empirical Black formula diffusion-generation-recombinationtrapping
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'The Theory of Field-Effect Transistors XII.The Bipolar Drift and Diffusion Currents(1-2-MOS-Gates on Thin-Thick Pure-Impure Base)
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作者 揭斌斌 薩支唐 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第7期1227-1241,共15页
The previous report (XI) gave the electrochemical-potential theory of the Bipolar Field-Effect Transistors. This report (XII) gives the drift-diffusion theory. Both treat 1-gate and 2-gate, pure-base and impure-ba... The previous report (XI) gave the electrochemical-potential theory of the Bipolar Field-Effect Transistors. This report (XII) gives the drift-diffusion theory. Both treat 1-gate and 2-gate, pure-base and impure-base, and thin and thick base. Both utilize the surface and bulk potentials as the parametric variables to couple the voltage and current equations. In the present drift-diffusion theory, the very many current terms are identified by their mobility multiplier for the components of drift current,and the diffusivity multiplier for the components of the diffusion current. Complete analytical driftdiffusion equations are presented to give the DC current-voltage characteristics of four common MOS transistor structures. The drift current consists of four terms: 1-D (One-Dimensional) bulk charge drift term, 1-D carrier space-charge drift term,l-D Ex^2 (transverse electric field) drift term,2-D drift term. The diffusion current consists of three terms: 1-D bulk charge diffusion term,l-D carrier space-charge diffusion term,and 2-D diffusion term. The 1-D Ex^2 drift term was missed by all the existing transistor theories, and contributes significantly, as much as 25 % of the total current when the base layer is nearly pure. The 2-D terms come from longitudinal gradient of the longitudinal electric field,which scales as the square of the Debye to Channel length ratio, at 25nm channel length with nearly pure base, (LD/L)^2 = 10^6 but with impurity concentration of 10^18cm^-3 , (LD/L)^2 = 10^-2 . 展开更多
关键词 bipolar field-effect transistor theory surface potential drift and diffusion theory single-gate impure-base double-gate impure-base
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Aging related methylation influences the gene expression of key control genes in colorectal cancer and adenoma 被引量:8
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作者 Orsolya Galamb Alexandra Kalmár +8 位作者 Barbara Kinga Barták árpád V Patai Katalin Leiszter Bálint Péterfia Barnabás Wichmann Gábor Valcz Gábor Veres Zsolt Tulassay Béla Molnár 《World Journal of Gastroenterology》 SCIE CAS 2016年第47期10325-10340,共16页
AIM To analyze colorectal carcinogenesis and age-related DNA methylation alterations of gene sequences associated with epigenetic clock CpG sites. METHODS In silico DNA methylation analysis of 353 epigenetic clock Cp ... AIM To analyze colorectal carcinogenesis and age-related DNA methylation alterations of gene sequences associated with epigenetic clock CpG sites. METHODS In silico DNA methylation analysis of 353 epigenetic clock Cp G sites published by Steve Horvath was performed using methylation array data for a set of 123 colonic tissue samples [64 colorectal cancer(CRC), 42 adenoma, 17 normal; GEO accession number: GSE48684]. Among the differentially methylated agerelated genes, secreted frizzled related protein 1(SFRP1) promoter methylation was further investigated in colonic tissue from 8 healthy adults, 19 normal children, 20 adenoma and 8 CRC patients using bisulfite-specific PCR followed by methylation-specific high resolution melting(MS-HRM) analysis. m RNA expression of age-related "epigenetic clock" genes was studied using Affymetrix HGU133 Plus2.0 whole transcriptome data of 153 colonic biopsy samples(49 healthy adult, 49 adenoma, 49 CRC, 6 healthy children)(GEO accession numbers: GSE37364, GSE10714, GSE4183, GSE37267). Whole promoter methylation analysis of genes showing inverse DNA methylationgene expression data was performed on 30 colonic samples using methyl capture sequencing.RESULTS Fifty-seven age-related Cp G sites including hypermethylated PPP1R16 B, SFRP1, SYNE1 and hypomethylated MGP, PIPOX were differentially methylated between CRC and normal tissues(P < 0.05, ?β≥ 10%). In the adenoma vs normal comparison, 70 CpG sites differed significantly, including hypermethylated DKK3, SDC2, SFRP1, SYNE1 and hypomethylated CEMIP, SPATA18(P < 0.05, ?β≥ 10%). In MS-HRM analysis, the SFRP1 promoter region was significantly hypermethylated in CRC(55.0% ± 8.4 %) and adenoma tissue samples(49.9% ± 18.1%) compared to normal adult(5.2% ± 2.7%) and young(2.2% ± 0.7%) colonic tissue(P < 0.0001). DNA methylation of SFRP1 promoter was slightly, but significantly increased in healthy adults compared to normal young samples(P < 0.02). This correlated with significantly increased SFRP1 m RNA levels in children compared to normal adult samples(P < 0.05). In CRC tissue the mR NA expression of 117 agerelated genes were changed, while in adenoma samples 102 genes showed differential expression compared with normal colonic tissue(P < 0.05, logF C > 0.5). The change of expression for several genes including SYNE1, CLEC3 B, LTBP3 and SFRP1, followed the same pattern in aging and carcinogenesis, though not for all genes(e.g., MGP). CONCLUSION Several age-related DNA methylation alterations can be observed during CRC development and progression affecting the m RNA expression of certain CRC- and adenoma-related key control genes. 展开更多
关键词 DNA methylation AGING Colorectal cancer ADENOMA Epigenetic drift Epigenetic clock Secreted frizzled related protein 1
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Causes and controlling pattern of sand hazards at the Danghe Reservoir of Dunhuang in Northwest China 被引量:1
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作者 XIE Sheng-bo QU Jian-jun PANG Ying-jun 《Journal of Mountain Science》 SCIE CSCD 2016年第11期1973-1983,共11页
Sand hazards are serious at the Danghe Reservoir of Dunhuang,and efforts to control sand are ineffective because disaster-causing mechanisms are currently unclear.The source of sandy materials,dynamic environment of b... Sand hazards are serious at the Danghe Reservoir of Dunhuang,and efforts to control sand are ineffective because disaster-causing mechanisms are currently unclear.The source of sandy materials,dynamic environment of blown sand,and controlling measures of the reservoir area are investigated using different methods,such as granularity analyses,wind regime and sand transport field observation and analyses,sand drift potential calculation.Accordingly,the sandy materials are found to derive chiefly from the Mingsha Mountain on the north side of the reservoir area.In addition,sand grain in the range of 0.50-0.25 mm and 0.25-0.10 mm are dominant.The prevailing sand-moving wind originates from the N direction,accounting for 15.38% of the yearly total,which coincides in the same direction with sand source,thereby increasing the severity of sand hazards in the reservoir area.The yearly sand DP is 1386.59 VU,the yearly RDP is 567.31 VU,the yearly RDP/DP is 0.41,and the yearly RDD is 183.15°.In the windy season(mainly in summer),sand materials are blown by wind from north to south,and then blocked by the Danghe River.The sand materials then move with an approximate east-west trend into the river channel and produce sediment,thereby causing adisaster.We propose that the sand-controlling pattern of the Danghe Reservoir is dominated by sand blocking in the outer fringe and sand fixing in the inner fringe.Applying windbreak and sand fixation to control sandy material movement into the river channel plays an important role in retarding sedimentation and extending the useful life of the Danghe Reservoir. 展开更多
关键词 Danghe Reservoir Sand source Wind direction Sand drift potential
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Dealumination kinetics of composite ZSM-5/mordenite zeolite during steam treatment: An in-situ DRIFTS study 被引量:2
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作者 Xiaoxiao Zhang Dangguo Cheng +1 位作者 Fengqiu Chen Xiaoli Zhan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第3期545-550,共6页
To get a better understanding of structural deactivation of ZSM-5/MOR during the catalytic cracking of n-heptane in the steam atmosphere, a comprehensive mechanism of hydrothermal dealumination was proposed through in... To get a better understanding of structural deactivation of ZSM-5/MOR during the catalytic cracking of n-heptane in the steam atmosphere, a comprehensive mechanism of hydrothermal dealumination was proposed through in-situ diffuse reflectance Fourier transform infrared spectroscopy(DRIFTS) in this work. The mechanism can be divided into two steps: firstly, the hydrolysis of four Al\\O bonds, and secondly, the self-healing of Si\\OH bonds accompanied with partial condensation of the extra-framework Al species. Accordingly, the kinetics of dealumination process has also been fully discussed. In the IR spectra, the range of 3450–3850 cm^(-1) could be deconvolved to distinguish the hydroxyl groups on the different position and calculate the consumption of each hydroxyl group during the reaction. Based on results from the in-situ DRIFTS, the kinetics of dealumination was hence developed and also in well agreement with the kinetics of deactivation of ZSM/MOR catalysts during the reaction in the presence of little coke deposits. 展开更多
关键词 Zeolite Dealumination Kinetics Hydrothermal treatment
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The Integration of Dual-domain Method for Estimating the Drift Function of Financial Assets
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作者 YE Xu-guo DU Xue-qiao 《Chinese Quarterly Journal of Mathematics》 CSCD 2011年第2期190-195,共6页
Time-domain state-domain methods are common approaches in modern financial analysis.Economic conditions vary time,drift function depends on time and price level for a given state variable.In this paper,to consistently... Time-domain state-domain methods are common approaches in modern financial analysis.Economic conditions vary time,drift function depends on time and price level for a given state variable.In this paper,to consistently estimate the bivariate drift function,our purpose a new dynamic integrated estimator by combing time-and state-domain methods for estimating drift function.And we establish its asymptotic properties and illustrates it outperforms some old ones by simulations. 展开更多
关键词 TIME-DOMAIN state-domain integrated estimator drift function
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Validation of the Model Obtained Ice Drift Fields Based on Satellite Derived Data Using a Vector Correlation Indexes in an Invariant Form
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作者 Vladimir Aleksandrovich Volkov Denis Mikhailovich Demchev Nikolay Evgenievich Ivanov 《Journal of Shipping and Ocean Engineering》 2017年第6期250-261,共12页
The article considers results of validation of a sea ice modeling data using a novel methodology on the vector algebra theoretical bases. The vectorial-algebraic approach developed and was in use in Russia for an anal... The article considers results of validation of a sea ice modeling data using a novel methodology on the vector algebra theoretical bases. The vectorial-algebraic approach developed and was in use in Russia for an analysis of time series of vector values--wind, currents ice drift etc. The vectorial-algebraic approach allows significantly compressing the initial information and most adequately describes the vector time series of full-scale and model data restricted by a set of statistical characteristics in the invariant form. For an express analysis of correlation of the modeling data and in situ (or satellite derived) data a system of simplified correlation invariant indicators was used. This methodology was applied for validation of vector values fields at the first time. The method gives an opportunity to describe a field of a vector correlation and detect an areas with different levels of correlation between model and in situ (or other reference) vector data. The work was carried out in the frame of the My Ocean Project (FP7). 展开更多
关键词 Sea ice vector correlation model validation ice drift.
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Getting out of town and social exclusion:How to resolve the "old drifts" pension embarrassment
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作者 SU Xiaoqiao 《International English Education Research》 2018年第3期56-58,共3页
The "Old drifts" faces the problem of old-age pension under the double background of leaving the country and relocatingfrom the place of migration. And with the increase in the number of "old drifting families." t... The "Old drifts" faces the problem of old-age pension under the double background of leaving the country and relocatingfrom the place of migration. And with the increase in the number of "old drifting families." the situation continues to grow. Through the analysis of the personal reasons and social system reasons of the" Old Floating Clan" pension gurus, the author proposes that the "Old Clan" old-age pension will be effective by realizing the economic foundation, actively re-socializing, promoting social co-ordination, introducing additional insurance types, and participating in multiple subjects, way, In order to protect the "old drift" off-farm elderly rights and interests. 展开更多
关键词 Get away from home: Social exclusion Old drifts: Pension embarrassment
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留学书屋
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《神州学人》 2005年第9期41-41,共1页
关键词 《生活中的经济学(第二版)》 《史记笺证》 《飘移》 《北美风情》 中国
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歌名串烧
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作者 邓慧娟 谭美凤(指导老师) 《创新作文(初中版)》 2006年第8期47-48,共2页
《一千年以后》,《我们》《飘移》到《第二天空》,你是我家喻户晓的《拯救》天使。于是《我们》也成了人间的《神话》,广为流传。
关键词 《我们》 《飘移》 《神话》
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Kinetic Instability of Anisotropic Drift Wave Accompanied by Field Aligned Currents in Solar Coronal Loop
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作者 Hafsa Naim Ch.Uzma G.Murtaza 《Communications in Theoretical Physics》 SCIE CAS CSCD 2018年第10期470-476,共7页
Solar coronal loops are frequently accompanied by the field-aligned currents, which drive instabilities if the drift velocity u0 > v A the Alfv′en velocity. For our choice of parameters, the critical threshold val... Solar coronal loops are frequently accompanied by the field-aligned currents, which drive instabilities if the drift velocity u0 > v A the Alfv′en velocity. For our choice of parameters, the critical threshold value of u0/v A is ~ 3.0 for growth and the corresponding current filling factor ~ 10-3-10-4. Below this value we are no longer in the kinetic regime.The coronal loops also have short-scale density gradients within each loop. The electron resonance in the presence of density gradient causes the drift mode to grow. We study the effect of these two free energy sources, the electron drift and the density gradient, in the presence of temperature anisotropy T⊥_α > T∥_α. These effects simultaneously exist in the coronae. Using gyrokinetic theory, we investigate the influence of these effects, examine how they interplay with each other and study the consequent growth of the magnetosonic wave. We observe that kinetic instability driven by density gradient can be suppressed by field-aligned currents. The temperature anisotropy with chosen signatures causes further stabilizing effect. The results may prove useful to study the heating mechanism of solar coronal loops, acceleration of particles and confinement of particles in the thermonuclear reactors. 展开更多
关键词 solar corona coronal loops temperature anisotropy density inhomogeneity field-aligned currents GYROKINETIC
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Quasineutral limit of a standard drift diffusion model for semiconductors
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作者 肖玲 PeterA.Markowich 王术 《Science China Mathematics》 SCIE 2002年第1期33-41,共9页
The limit of vanishing Debye length (charge neutral limit) in a nonlinear bipolar drift-diffusion model for semiconductors without pn-junction (i.e. without a bipolar background charge) is studied. The quasineutral li... The limit of vanishing Debye length (charge neutral limit) in a nonlinear bipolar drift-diffusion model for semiconductors without pn-junction (i.e. without a bipolar background charge) is studied. The quasineutral limit (zero-Debye-length limit) is performed rigorously by using the weak compactness argument and the so-called entropy functional which yields appropriate uniform estimates. 展开更多
关键词 quasineutral limit nonlinear drift-diffusion equations entropy method
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Practical Reference-Frame-Independent Measurement-Device-Independent Quantum Key Distribution Systems Against the Worst Relative Rotation of Reference Frames
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作者 Chun-Mei Zhang Jian-Rong Zhu Qin Wang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2018年第10期379-383,共5页
Reference-frame-independent measurement-device-independent QKD(RFI-MDI-QKD), immune to both the slow unknown drift of reference frames and detector side channel attacks, can generate information-theoretic secure keys.... Reference-frame-independent measurement-device-independent QKD(RFI-MDI-QKD), immune to both the slow unknown drift of reference frames and detector side channel attacks, can generate information-theoretic secure keys. Despite its natural resistance to the slow drift of reference frames, the performance of practical RFI-MDI-QKD systems descends with the increasing drift of reference frames. In this paper, we demonstrate the worst relative rotation of reference frames for practical RFI-MDI-QKD systems, and investigate their performance against the worst-case scenario,both of which are unclear to date. Simulation results show that, practical RFI-MDI-QKD systems can achieve quite good performance even against the worst-case scenario, which clearly demonstrates that it is possible to implement practical MDI-QKD systems with freely drifting reference frames. 展开更多
关键词 reference-frame-independent measurement-device-independent quantum key distribution relative rotation
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