期刊文献+
共找到35篇文章
< 1 2 >
每页显示 20 50 100
A Corpus-based Contrastive Study of Cultural Difference——A Case Study of Passive Voice Used in English and Chinese 被引量:1
1
作者 康克兢 《海外英语》 2013年第10X期233-234,248,共3页
Passive voice is a common linguistic phenomenon both in Chinese and in English, while it is used differently in each language system. This paper takes the grammar features of passive voice in both Chinese and English ... Passive voice is a common linguistic phenomenon both in Chinese and in English, while it is used differently in each language system. This paper takes the grammar features of passive voice in both Chinese and English as an example, collecting corpus data of passive voice in the two languages, to comparatively analyze the cultural difference reflected from the usage of languages. Getting to know this kind of cultural difference would help us to better understand linguistic phenomena in second language acquisition, and to master them better. 展开更多
关键词 passive VOICE CULTURAL DIFFERENCE corpus based stu
下载PDF
English BNP identification based on corpus-trained decision tree
2
作者 孟遥 赵铁军 +1 位作者 李生 张晓光 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2001年第4期383-386,共4页
Finding simple, non recursive, base noun phrase is an important step for many natural language processing applications. This paper presents a new corpus based approach using decision tree for that purpose. In contrast... Finding simple, non recursive, base noun phrase is an important step for many natural language processing applications. This paper presents a new corpus based approach using decision tree for that purpose. In contrast to previous methods for Base NP identification, we adopt a decision tree trained from Penn Treebank to identify Base NP. And a self learning mechanism is further integrated into our model. Experimental results show good performances using our method. The method can also be applied to processing of any other language. 展开更多
关键词 base NP decision tree corpus
下载PDF
A 330-500 GHz Zero-Biased Broadband Tripler Based on Terahertz Monolithic Integrated Circuits 被引量:2
3
作者 任田昊 张勇 +4 位作者 延波 徐锐敏 杨成樾 周静涛 金智 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第2期31-34,共4页
A 330-500 GHz zero-biased broadband monolithic integrated tripler is reported. The measured results show that the maximum efficiency and the maximum output power are 2% and 194μW at 348 GHz. The saturation characteri... A 330-500 GHz zero-biased broadband monolithic integrated tripler is reported. The measured results show that the maximum efficiency and the maximum output power are 2% and 194μW at 348 GHz. The saturation characteristic test shows that the output i dB compression point is about -8.5 dBm at 334 GHz and the maximum efficiency is obtained at the point, which is slightly below the 1 dB compression point. Compared with the conventional hybrid integrated circuit, a major advantage of the monolithic integrated circuit is the significant improvement of reliability and consistency. In this work, a terahertz monolithic frequency multiplier at this band is designed and fabricated. 展开更多
关键词 InP InGaAs A 330-500 GHz Zero-Biased Broadband Tripler based on Terahertz Monolithic Integrated Circuits dBm SBD
下载PDF
SELECTING CLUSTER MODEL IN Sn - BASED SOLDER ALLOY DESIGN WITH DV - X_α CALCULATION METHOD
4
作者 C. Q. Wang and W. F. Feng National ho. of Advanced welding Technolgy, HIT, Harbin 150001,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2000年第1期84-88,共5页
Applying calculation method in alloy design should be an important tendency due to its characters of inexpensive cost, high efficiency and prediction. DOS calculations of AuSn, AsSn and SbSn Sn- based alloys have ... Applying calculation method in alloy design should be an important tendency due to its characters of inexpensive cost, high efficiency and prediction. DOS calculations of AuSn, AsSn and SbSn Sn- based alloys have been investigated by employing DV - Xa method, in which different cluster models were adopted to calculate electron structure.It is proved that some regulations must be taken into ac- count in order to carry out alloy design calculation successfully,which are described in this paper in detail. 展开更多
关键词 Cluster model Sn - based alloy design DV - X_a calculation method DOS
下载PDF
Preparation and the Pore Structure of Viscose-based Activated Carbon Fibers Treated with Pretreatment Reagents
5
作者 罗艳 黄永辉 《Journal of China Textile University(English Edition)》 EI CAS 2000年第2期16-18,共3页
The viscose rayon was pretreated with four different pre-treatment reagents respectively, and the preparation ofactivated carbon fibers (ACF) was performed undersame carbonizing and activating conditions. The poresize... The viscose rayon was pretreated with four different pre-treatment reagents respectively, and the preparation ofactivated carbon fibers (ACF) was performed undersame carbonizing and activating conditions. The poresize distribution, the specific surface area, and the porestructure parameter of these viscose - based ACF werestudied by using quartz spring balance BET- weightmethod. The experiment result indicates that the poresize distribution and the pore structure parameter ofACF is varied by using different pretreatment reagents. 展开更多
关键词 PRETREATMENT REAGENT VISCOSE - based ACF PORE size PORE structure specific surface area
下载PDF
GRAPHICAL COMPUTING METHOD ON FOUR-BAR LINKAGE(1)——Inflexion Circle,Focal Axis,Ball's Point,Centering-point Curve and Circling-point Curve For Four ISPs,Coupler Curves Based on Ball's Points——
6
作者 周晋康 《苏州大学学报(工科版)》 CAS 1992年第S2期27-34,共8页
By means of programs GTMPAC based- on generalized triangle method,analysis and synthesis of mechanism design in accordance with absolutely graphicalmethod( absolutely germetrical method) are developed.In this paper,we... By means of programs GTMPAC based- on generalized triangle method,analysis and synthesis of mechanism design in accordance with absolutely graphicalmethod( absolutely germetrical method) are developed.In this paper,we make aspecial study about centering- point curve and circling- point curve and couplercurves based on Ball’s points. 展开更多
关键词 Ball’s POINT centering - POINT CURVE and CIRCLING CURVE four ISPS Coupler curves based on BALLS Points
下载PDF
NEW SOLID BASE DERIVED FROM AIPO4-5 SUPPORTED KF
7
作者 Jian Hua ZHU Qin Hug XU Hideshi HATTORI(Chemistry Department, Nanjing University.Nanjing 210093,China.)(Centre for Advanced Research of Energy Technology, Hokkaido University,Sapporo 060.Japan) 《Chinese Chemical Letters》 SCIE CAS CSCD 1996年第7期671-674,共4页
Dispersion of KF on AlPO4-5 molecular sieve created basic sites and caused 1654 cm- band of bidentate carbonate in CO2 adsorption.After pre-treated above 823K. 5%KF/AlPO4-5exhibited basic catalytic activity in the iso... Dispersion of KF on AlPO4-5 molecular sieve created basic sites and caused 1654 cm- band of bidentate carbonate in CO2 adsorption.After pre-treated above 823K. 5%KF/AlPO4-5exhibited basic catalytic activity in the isomerization of butenes at 273K. and the activity increasedwith the pre-treatment temperature up to 923K. 展开更多
关键词 NEW SOLID base DERIVED FROM AIPO4-5 SUPPORTED KF
下载PDF
Biological Evaluation of New Schiff Bases: Synthesized from 4-Amino-3,5-dimethyl-1,2,4-triazole, Phenathroline and Bipyridine Dicarboxaldehydes
8
作者 Md. Shafiqul Islam Mohammad R. Karim +2 位作者 William Boadi Seyi Falekun Aminul H. Mirza 《Advances in Biological Chemistry》 2016年第6期180-192,共13页
Four new Schiff bases with promising anticancer activity have been synthesized from 4-amino-3,5-dimethyl-1,2,4-triazole and di-pyridyl-aldehydes. Structures have been established by various spectroscopic methods. The ... Four new Schiff bases with promising anticancer activity have been synthesized from 4-amino-3,5-dimethyl-1,2,4-triazole and di-pyridyl-aldehydes. Structures have been established by various spectroscopic methods. The compounds were tested in vitro to study their cytotoxicity and anti-oxidative activity in human lung carcinoma (A549), breast carcinoma (BT549), prostate adenocarcinoma (PC3) and mouse preadipocytes (3T3-L1) cells. Compound 1 was found to increase Glutathione (GSH) level slightly in all four cell lines. Compound 4 showed better selectivity and cytotoxicity against both BT549 and A549 cells compared to the anticancer drug tamoxifen. With the exception of compound 4 which reduced GSH levels in A549 and BT549, all other compounds maintained GSH levels in comparison to their respective controls. 展开更多
关键词 [2 2’-Bipyridine]-5 5’-dicarboxaldehyde Schiff bases Anticancer GLUTATHIONE ANTI-BACTERIAL
下载PDF
RE Production Base Will Be Built in Baotou During 2006-2010
9
《China Rare Earth Information》 2005年第11期3-3,共1页
关键词 2010 RE Production base Will Be Built in Baotou During 2006-2010 BE
下载PDF
含香豆素骨架水杨醛Schiff base荧光材料的制备及光谱性能研究 被引量:4
10
作者 冯雷 禹兴海 +2 位作者 金淑萍 徐建斌 刘娜 《化学试剂》 CAS CSCD 北大核心 2012年第3期257-260,共4页
以间苯二酚和乙酰乙酸乙酯为原料,草酸做催化剂,在无溶剂的条件下,经Pechmann反应催化合成了7-羟基-4-甲基香豆素,再经硝化、还原得到3-氨基7-羟基-4-甲基香豆素。利用3-氨基7-羟基-4-甲基香豆素与水杨醛缩合反应,制备了新型的含香豆素... 以间苯二酚和乙酰乙酸乙酯为原料,草酸做催化剂,在无溶剂的条件下,经Pechmann反应催化合成了7-羟基-4-甲基香豆素,再经硝化、还原得到3-氨基7-羟基-4-甲基香豆素。利用3-氨基7-羟基-4-甲基香豆素与水杨醛缩合反应,制备了新型的含香豆素骨架水杨醛Schiff base衍生物,其结构由IR、1HNMR和元素分析确证。通过研究化合物紫外吸收光谱及荧光光谱发现该化合物具有优异光学活性。 展开更多
关键词 7-羟基-4-甲基香豆素 水杨醛 SCHIFF base 光学性能
下载PDF
苯胺α-呋喃甲醛双齿单希夫碱过渡金属配合物的合成和表征
11
作者 南光明 吴进 《西昌学院学报(自然科学版)》 2005年第2期71-73,共3页
本文合成了单希夫碱配体-苯胺缩α-呋喃甲醛,使用过渡金属化合物FeCl3.6H2O、MnCl2.4H2O、CoCl2·6H2O、NiCl·26H2O与之配合生成了四种配合物,并用1HNMR、IR及元素分析等测试技术予以表征。
关键词 SCHIFF base 配合物 苯胺 α-呋喃甲醛 过渡金属
下载PDF
π-旋转LDPC码译码算法及其量化研究 被引量:1
12
作者 刘文焘 李强 李少谦 《信息技术》 2005年第11期38-40,43,共4页
通过仿真分析论述了Normalized BP-Based算法对于π-旋转LDPC码具有很好的译码性能,并对此算法它进行了定点分析,从仿真结果可知,使用BPSK调制时,在白高斯噪声信道下,Normalized BP-Based译码算法使用正确的量化方案时可以获得和浮点几... 通过仿真分析论述了Normalized BP-Based算法对于π-旋转LDPC码具有很好的译码性能,并对此算法它进行了定点分析,从仿真结果可知,使用BPSK调制时,在白高斯噪声信道下,Normalized BP-Based译码算法使用正确的量化方案时可以获得和浮点几乎一致的性能。 展开更多
关键词 π-旋转LDPC码 量化 Normalized BP—based算法 误码率
下载PDF
Synthesis and Crystal Structure of a Co(II) Complex with Schiff Base and Imidazole Ligand 被引量:1
13
作者 WU Lian-Bin HU Zi-Qiang LAI Guo-Qiao 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第5期567-571,共5页
The title compound, [Co(C3H4N2)2(C22H18N2O4)]·5H2O (Mr = 659.56), has been prepared and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group P21/n... The title compound, [Co(C3H4N2)2(C22H18N2O4)]·5H2O (Mr = 659.56), has been prepared and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic, space group P21/n, a = 9.6808(2), b = 26.7204(5), c = 12.7993(3) A, β = 100.9340(10)°, V= 3250.75(12) A^3, Z = 4, Dc = 1.348 g/cm^3,μ = 0.586 mm^-1, F(000) = 1380, S = 1.131, R = 0.0689 and wR = 0.1883 for 4782 observed reflections (Ⅰ 〉 2σ(Ⅰ)). The title crystal consists of Co(Ⅱ) complex and lattice water molecules. The Co(Ⅱ) complex assumes a distorted octahedral coordination geometry, formed by one Schiff base dianion phenylenediamine-3-methoxysali-cylaldehyde and two imidazole ligands. The π-π stacking interaction occurs between nearly parallel benzene rings of the neighboring complexes. 展开更多
关键词 cobalt(Ⅱ) complex Schiff base crystal structure π-π stacking
下载PDF
Synthesis and Crystal Structure of a New Nickel(II) Complex with Unsymmetric Quadridentate Schiff Base Containing Oxime 被引量:1
14
作者 ZHANGGuo-Juan FENGYun-Long GAOShan 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2005年第4期454-456,共3页
The title complex, C18H15N3NiO3, has been prepared and characterized by X-ray diffraction analysis. It crystallizes in the monoclinic system, space group Cc with a = 10.939(2), b = 22.909(5), c = 6.907(1) ?, β = 11... The title complex, C18H15N3NiO3, has been prepared and characterized by X-ray diffraction analysis. It crystallizes in the monoclinic system, space group Cc with a = 10.939(2), b = 22.909(5), c = 6.907(1) ?, β = 116.75(3)°, V = 1545.7(5) ?, Z = 4, Mr = 380.04, F(000) = 784, Dc = 1.633 g/cm3 and μ(MoKα) = 1.279 mm–1. The structure was refined to R = 0.0472 and wR = 0.0893 for 2571 observed reflections with I > 2σ(I). The absolute structure Flack parameter X is 0.01(2). In this crystal structure, strong face-to-face π-π stacking interactions between adjacent molecules lead to a one-dimensional chain structure. 展开更多
关键词 nickel(II) complex Schiff base OXIME crystal structure π-π stacking interaction
下载PDF
Kinetic, electronic properties and conductivity studies of ((12Z)N-(5Z)-1-bromo-5-(phenylimino)-1H-pyrrol-2(5H)-ylidene benzenmine {ArN(CNBrCCHCH)NAr} (Ar = C6H5) 被引量:1
15
作者 Salem Et. Ashoor Noori Y. Salman 《Journal of Chemistry and Chemical Engineering》 2009年第10期51-56,共6页
Kinetic and conductivity of new Schiff bases compounds such ((12Z)N-(5Z)-1-bromo-5-(phenylimino)-1H- pyrrol-2(5 H)-ylidene)benzenamine {ArN(CNBrCCHCH)NAr} (Ar = C6H5) incorporating the chelating diamino ... Kinetic and conductivity of new Schiff bases compounds such ((12Z)N-(5Z)-1-bromo-5-(phenylimino)-1H- pyrrol-2(5 H)-ylidene)benzenamine {ArN(CNBrCCHCH)NAr} (Ar = C6H5) incorporating the chelating diamino has been studied in this paper and was found a second order of this reaction. Electronic Properties using hyperchem program study has been improved for this compound such angel and bond distance, and then this compound was defining as electric conductivity and did prove to be useful for conduclively compound. 展开更多
关键词 Schiff bases compounds ((12Z)N-(5Z)-1-bromo-5-(phenylimino)- 1H-pyrrol-2(5H)-ylide ne)benzenamine chelating diamino: electronic properties
下载PDF
Synthesis and Crystal Structure of 4-Nitro-2-[(2-diethylaminoethylimino)methyl]phenol
16
作者 WANG Feng-Wu WEI Yi-Jun ZHU Qi-Yong 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第10期1179-1182,共4页
The title Schiff base compound C13H19N3O3 synthesized by the condensation of equimolar 5-nitrosalicylaldehyde and N,N-diethylethane-1,2-diamine consists of two independent molecules. The compound was characterized by ... The title Schiff base compound C13H19N3O3 synthesized by the condensation of equimolar 5-nitrosalicylaldehyde and N,N-diethylethane-1,2-diamine consists of two independent molecules. The compound was characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbca with a = 13.151 (3), b = 20.609(4), c = 20.991 (4) °A, Z = 16, V = 5689(2) °A^3, Dc = 1.239 g/cm^3, Mr = 265.31, λ(MoKa) = 0.71073 °A, μ= 0.089 mm^-1, F(000) = 2272, R = 0.0732 and wR = 0.1454. A total of 5264 unique reflections were collected, of which 2023 with I 〉 2σ(I) were observed. As expected, the molecule adopts trans configuration about the C=N double bond. The molecules in the crystal are linked through intermolecular hydrogen bonds and π-π interactions, forming a 3-D network. 展开更多
关键词 Schiff base crystal structure hydrogen bonds π-π interactions
下载PDF
Green fuel from coal via Fischer-Tropsch process: scenario of optimal condition of process and modelling
17
作者 Hossein Atashil Somayyeh Veiskarami 《International Journal of Coal Science & Technology》 EI 2018年第2期230-243,共14页
Extracting, transportation and the using from fossil fuels can damage to the hydrosphere, the biosphere and the Earth's atmosphere. But humans always need to this valuable substance. The production of oil derivatives... Extracting, transportation and the using from fossil fuels can damage to the hydrosphere, the biosphere and the Earth's atmosphere. But humans always need to this valuable substance. The production of oil derivatives by means of forest waste and coal through the Fischer-Tropsch process is an appropriate solution for the cleanliness of all parts of the environment. For the production of favorite products by the synthesis of Fischer-Tropsch, the performance of the catalyst under different operating conditions should be predictable. For this reason, in this paper, eight mathematical models were determined for the selectivity of five products of methane, light hydrocarbons, gasoline, diesel and wax based on three factors of reduction temperature, time on stream, and He/CO ratio inlet gas on iron-based catalyst. The results showed that the reduction temperature factor had the most effective on the selectivity of hydrocarbon products, exception diesel, so that the increase of the reduction temperature led to increase of the selectivity of methane, light hydrocarbons, gasoline and reduce of the degree of selectivity of the wax and vice versa. For the diesel selectivity, factor of the He/CO ratio inlet gas was the most effective than other factors. 展开更多
关键词 Fischer-Tropsch process - Selectivity model Iron based catalyst BIOMASS Oil derivatives
下载PDF
A Study of the Correlation between Angiotensin (1-7) and the Histopathological Changes in the Penises of Experimentally Diabetic Rats
18
作者 Abdelaal M. El Kamshoushi Nagat Sobhy +2 位作者 Suzan F. Helal Passainte S. Hassaan Heba Omar 《Open Journal of Endocrine and Metabolic Diseases》 2018年第3期81-92,共12页
Background: Diabetes mellitus is an important risk factor for erectile dysfunction. Renin-angiotensin system with its branches Angiotensin II and Angiotensin 1-7 [Ang-(1-7)] are altered in diabetes and could affect er... Background: Diabetes mellitus is an important risk factor for erectile dysfunction. Renin-angiotensin system with its branches Angiotensin II and Angiotensin 1-7 [Ang-(1-7)] are altered in diabetes and could affect erection. So, in this study we determine the level of Ang-(1-7), nitrite (the major nitric oxide metabolite) and histopathological changes in penile tissues of type I diabetic rats. A total of 60 male albino rats were divided into two groups: group I (control) and group II (diabetic) for either 4 weeks in group IIa, or 8 weeks in group IIb. Diabetes was induced by intraperitoneal injection of streptozotocin (60 mg/kg). Penile levels of Ang-(1-7), nitrite and histopathological examination were assessed at 4 and 8 weeks after diabetes induction. Results: Ang-(1-7) and nitrite were decreased in diabetic rats at 4 weeks and continued to be lower at 8 weeks for Ang-(1-7) only. Loss of corpus cavernosum smooth muscle was present in 25% and 85% of rats at 4 and 8 weeks of diabetes respectively (P Conclusion: Diabetes induced progressive decrease in the release of Ang-(1-7) and nitric oxide from the corpora cavernosa in a time-dependent manner with concomitant fibro-muscular changes that end by corporal fibrosis affecting subsequently erectile functions. 展开更多
关键词 ANGIOTENSIN 1-7 corpus Cavernosum Erectile DYSFUNCTION DIABETES MELLITUS RATS
下载PDF
Synthesis of Folate-Appended <i>β</i>-Cyclodextrin Using Phenanthroline as Linker for Cancer Targeting Drug Delivery
19
作者 Nadim S. Russel Punam K. Paul +1 位作者 Mohammad Karim Byeongwoon Song 《International Journal of Organic Chemistry》 2019年第1期47-66,共20页
Here we have synthesized cancer targeting drug delivery system that contains β-cyclodextrin as a drug carrier and folic acid as a targeting ligand. Folic acid was selected as a cancer targeting ligand because folic a... Here we have synthesized cancer targeting drug delivery system that contains β-cyclodextrin as a drug carrier and folic acid as a targeting ligand. Folic acid was selected as a cancer targeting ligand because folic acid receptors are highly expressed in a variety of tumor types. β-cyclodextrin and folic acid were connected through a linker [1,10-phenanthroline or 5-(hydroxymethyl) furfural]. β-cyclodextrin and folic acid were attached to the linker by formation of Schiffbase and ester, respectively. Our targeted synthetic products were confirmed by NMR, Mass and IR spectroscopy. We anticipate that our synthetic products can confer cancer cell-specific drug delivery as well as desired properties such as nanoparticle formation. 展开更多
关键词 Schiff base β-Cyclodextrin p-Toluenesulfonylchloride Ethylenediamine Folic Acid 2 9-Dimethyl-1 10-PHENANTHROLINE Hemi-Hydrate 5-(Hydroxymethyl-2-Furaldehyde)
下载PDF
Battle Royale Optimization with Fuzzy Deep Learning for Arabic Sentiment Classification
20
作者 Manar Ahmed Hamza Hala J.Alshahrani +3 位作者 Jaber S.Alzahrani Heba Mohsen Mohamed I.Eldesouki Mohammed Rizwanullah 《Computer Systems Science & Engineering》 SCIE EI 2023年第8期2619-2635,共17页
Aspect-Based Sentiment Analysis(ABSA)on Arabic corpus has become an active research topic in recent days.ABSA refers to a fine-grained Sentiment Analysis(SA)task that focuses on the extraction of the conferred aspects... Aspect-Based Sentiment Analysis(ABSA)on Arabic corpus has become an active research topic in recent days.ABSA refers to a fine-grained Sentiment Analysis(SA)task that focuses on the extraction of the conferred aspects and the identification of respective sentiment polarity from the provided text.Most of the prevailing Arabic ABSA techniques heavily depend upon dreary feature-engineering and pre-processing tasks and utilize external sources such as lexicons.In literature,concerning the Arabic language text analysis,the authors made use of regular Machine Learning(ML)techniques that rely on a group of rare sources and tools.These sources were used for processing and analyzing the Arabic language content like lexicons.However,an important challenge in this domain is the unavailability of sufficient and reliable resources.In this background,the current study introduces a new Battle Royale Optimization with Fuzzy Deep Learning for Arabic Aspect Based Sentiment Classification(BROFDL-AASC)technique.The aim of the presented BROFDL-AASC model is to detect and classify the sentiments in the Arabic language.In the presented BROFDL-AASC model,data pre-processing is performed at first to convert the input data into a useful format.Besides,the BROFDL-AASC model includes Discriminative Fuzzy-based Restricted Boltzmann Machine(DFRBM)model for the identification and categorization of sentiments.Furthermore,the BRO algorithm is exploited for optimal fine-tuning of the hyperparameters related to the FBRBM model.This scenario establishes the novelty of current study.The performance of the proposed BROFDL-AASC model was validated and the outcomes demonstrate the supremacy of BROFDL-AASC model over other existing models. 展开更多
关键词 Arabic corpus aspect based sentiment analysis arabic language deep learning battle royale optimization natural language processing
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部