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Morphological Change of Starch Grain Based on Simulated Experiment and its Significance of Agricultural Archaeology——Taking Wheat as an Example 被引量:2
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作者 万智巍 杨晓燕 +1 位作者 马志坤 刘光旭 《Agricultural Science & Technology》 CAS 2011年第11期1621-1624,共4页
[Objective] The aim was to research and identify starch grain microfossil found in archaeological sites in China, and to find appropriate procedures for the starch grain analysis experiment.[Method] Wheat starch grain... [Objective] The aim was to research and identify starch grain microfossil found in archaeological sites in China, and to find appropriate procedures for the starch grain analysis experiment.[Method] Wheat starch grain size distribution was analyzed, and some simulated experiments were carried out, like mortar grinding, ultrasonic treatment, hydrochloric acid and hydrogen peroxide immersion, drying treatment, and so on. [Result] The mean size of wheat starch grains had increased in the growth process. Mortar grinding would make wheat starch grains larger than untreated sample. Long time of ultrasonic treatment can also make the starch grain size larger. 10% HCl and 6% H2O2 would have little effects on morphological feature of wheat starch grains. Low temperature heating did not cause starch grains to be gelatinized. [Conclusion] These experiment results can improve the accuracy of starch grain microfossil identification in the archaeological site. Starch grain analysis may be a utility and effective analytical tool in studying the origin of agriculture and the dispersal of crops in China. 展开更多
关键词 Starch grain analysis WHEAT Morphological change Agricultural archaeology
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Characterization of pitting corrosion of 7A60 aluminum alloy by EN and EIS techniques 被引量:10
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作者 王学慧 王吉会 付丛伟 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第12期3907-3916,共10页
The pitting corrosion behaviors of 7A60 aluminum alloy in the retrogression and re-aging (RRA) temper were investigated by electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques, ... The pitting corrosion behaviors of 7A60 aluminum alloy in the retrogression and re-aging (RRA) temper were investigated by electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques, and the microstructure and the second phase content of the alloy were observed and determined by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The results show that there exist two different corrosion stages for 7A60 alloy in 3.5%NaCl solution, and the corrosion process can be detected by the appearance of EIS spectrum with two capacitive time constants and the wavelet fractal dimension D extracted from EN. SEM and EDS results also demonstrate that severe pitting corrosion in 7A60 alloy is mainly caused by electrochemical active MgZn2 particles, secondly by Al2MgCu and Mg2Si. Al7Cu2Fe particles make little contribution to the pitting corrosion of 7A60 alloy. 展开更多
关键词 7A60 aluminum alloy constituent particles pitting corrosion electrochemical impedance spectroscopy electrochemical noise wavelet fractal dimension
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整体式汽车冷暖空调的开发
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作者 游新民 《制冷空调技术》 1997年第2期44-50,共7页
作为确保乘员们舒适性和安全所必备的功能,汽车空调的安装率目前已达到了100%。左右,但为了提高车辆的乘座性和配置高级音响和驾驶系统,则必须使汽车空调小形化。本文介绍了将空调部件小形化和整体机组化,从而使汽车空调更加小... 作为确保乘员们舒适性和安全所必备的功能,汽车空调的安装率目前已达到了100%。左右,但为了提高车辆的乘座性和配置高级音响和驾驶系统,则必须使汽车空调小形化。本文介绍了将空调部件小形化和整体机组化,从而使汽车空调更加小形化。 展开更多
关键词 整体式 汽车 空调器 小形化
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Optimization Method of the Side Member of the Automobile Seat
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作者 季学荣 丁晓红 罗智恒 《Journal of Donghua University(English Edition)》 EI CAS 2010年第6期841-845,共5页
Buckling is the primary cause of failure of a side member in condition of overloading,so buckling stability should be taken into consideration in the design optimization of side member.On the other hand,lightweight is... Buckling is the primary cause of failure of a side member in condition of overloading,so buckling stability should be taken into consideration in the design optimization of side member.On the other hand,lightweight is always a pursuing objective of manufacturer of automobile seat.Thus both the buckling stability and lightweight are considered in the suggested design optimization method of the side member of automobile seats.The method has two design phases.Firstly,the optimal shape of back curve by using shape optimization was obtained in which the lightweight of the side member was set to be the design objective.Secondly,optimal size and distribution of grooves on side member was obtained by topography optimization in which the buckling critical load was set to be the design objective.A typical design example shows that the buckling critical load of the optimal side member is increased by 25.98%,and the weight is decreased by 3.7% simultaneously. 展开更多
关键词 automobile seat back buckling stability LIGHTWEIGHT shape optimization topography optimization
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Effects of pharmacological serum from normal and liver fibrotic rats on HSCs 被引量:7
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作者 Xi-XianYao TaoLv 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第16期2444-2449,共6页
AIM: To make drug sera of Salvia miltiorrhiza and Yigankang, both of which are Chinese herbs that activate bleeding and eliminate stasis, in normal rats and those with liver fibrosis, respectively. To investigate and ... AIM: To make drug sera of Salvia miltiorrhiza and Yigankang, both of which are Chinese herbs that activate bleeding and eliminate stasis, in normal rats and those with liver fibrosis, respectively. To investigate and compare the effects of the two different drug sera on the proliferation and activation of hepatic stellate cells (HSCs). METHODS: Some rats were induced with liver fibrosis: 40% carbon tetrachloride (CCI4) subcutaneous injection, twice a week for 9 wk. Salvia miltiorrhiza, Yigankang, colchicines and normal saline were administered into the stomachs of normal rats and those with liver fibrosis. Drug sera were extracted 5 d later. HSCs in vitro were cultivated in different drug sera for 24 h. The rates of proliferation and expression of a-smooth muscle actin (α-SMA) were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and immunocyt-ochemistry stain, respectively. RESULTS: The drug sera from normal and liver fibrotic rats could be used to cultivate HSCs and to observe the effects of the corresponding components of herbs on HSCs. Salvia miltiorrhiza and Yigankang had better inhibitory effects on HSCs than colchicines (MTT: normal drug serum: Salvia miltiorrhiza 0.42 ±0.08, Yigankang 0.32±0.10 vs colchicines 0.45±0.12 pathological drug serum: Salvia miltiorrhiza 0.33±0.02, Yigankang 0.26±0.01 vs colchicines 0.41±0.09. P<0.05). The drug sera of Salvia miltiorrhiza, Yigankang from liver fibrotic rats had a stronger inhibitory effect than the same ones from normal rats (MTT: Salvia miltiorrhiza: normal drug serum 0.42±0.08 vs pathological drug serum 0.33±0.02. Yigankang: normal drug serum 0.32±0.10 vs pathological drug serum 0.26±0.01. P<0.05) CONCLUSION: Salvia miltiorrhiza and Yigankang could inhibit the expression of a-SMA and the proliferation of HSCs. The drug sera from normal and liver fibrotic rats had different effects on HSCs, probably due to different metabolic processes, effective components and different quantities of drug contents in drug sera from rats with different states of liver. 展开更多
关键词 Seropharmocological method Hepatic stellate cell α-Smooth muscle actin SALVIA Yigankang
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Crystal Growth,Structure and Morphology of Rifapentine Methanol Solvate 被引量:3
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作者 周堃 李军 +1 位作者 罗建洪 金央 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2012年第3期602-607,共6页
Rifapentine, an important antibiotic, was crystallized from methanol solvent in the form of its methanol solvate. The crystal structure of rifapentine methanol solvate belongs to monoclinic, space group P21, with the ... Rifapentine, an important antibiotic, was crystallized from methanol solvent in the form of its methanol solvate. The crystal structure of rifapentine methanol solvate belongs to monoclinic, space group P21, with the unit cell parameters of a = 1.2278(3) nm, b = 1.9768(4) rim, c = 1.2473(3) nm, Z= 2, and β = 112.35(3). The parallelepiped.morphology was also predicted by Materials Studio simulation program.. The influence of intermolecular in-teraction was taken into account in the attachment energy model. The crystal shape fits the calculated morphology well, which was performed on the potential energy minimized model using a generic DREIDING 2.21 force fieldand developed minimization protocol with derived'partial charges. 展开更多
关键词 RIFAPENTINE crystal structure morphology CRYSTALLIZATION
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Morphological Characteristics of Floral Organ at Different Microspore Developmental Stage in Balsam Pear (Momordica Charantia L.) 被引量:2
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作者 Yi Tang Bin Liu Ji Liu Chao Ma Ke Xu Huanxiu Li 《Journal of Life Sciences》 2010年第6期35-38,共4页
The relationship between microspore developmental stages and morphological characteristics of floral organ in balsam pear was studied. The results showed that flower buds developed a series of morphological changes at... The relationship between microspore developmental stages and morphological characteristics of floral organ in balsam pear was studied. The results showed that flower buds developed a series of morphological changes at different microspore developmental stages, and morphological characteristics of floral organ were significantly different when sampling from different part or cultivar of balsam pear. Anther at late-uninucleate stage was best for culture, in which stage flower buds swelled obviously, and white floss on the surface reduced. In addition, calyxes were obvious but did not spread, and the most of anthers were light green. 展开更多
关键词 Balsam pear (Momordica charantia L.) MICROSPORE floral organ.
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Changes of smooth muscle contractile filaments in small bowel atresia 被引量:1
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作者 Stefan Gfroerer Henning Fiegel +2 位作者 Priya Ramachandran Udo Rolle Roman Metzger 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第24期3099-3104,共6页
AIM:To investigate morphological changes of intestinal smooth muscle contractile fibres in small bowel atresia patients.METHODS:Resected small bowel specimens from small bowel atresia patients(n = 12) were divided int... AIM:To investigate morphological changes of intestinal smooth muscle contractile fibres in small bowel atresia patients.METHODS:Resected small bowel specimens from small bowel atresia patients(n = 12) were divided into three sections(proximal,atretic and distal).Standard histology hematoxylin-eosin staining and enzyme immunohistochemistry was performed to visualize smooth muscle contractile markers-smooth muscle actin(SMA) and desmin using conventional paraffin sections of the proximal and distal bowel.Small bowel from agematched patients(n = 2) undergoing Meckel's diverticulum resection served as controls.RESULTS:The smooth muscle coat in the proximal bowel of small bowel atresia patients was thickened compared with control tissue,but the distal bowel was unchanged.Expression of smooth muscle contractile fibres SMA and desmin within the proximal bowel was slightly reduced compared with the distal bowel and control tissue.There were no major differences in the architecture of the smooth muscle within the proximal bowel and the distal bowel.The proximal and distal bowel in small bowel atresia patients revealed only minimal differences regarding smooth muscle morphology and the presence of smooth muscle contractile filament markers.CONCLUSION:Changes in smooth muscle contractile filaments do not appear to play a major role in postoperative motility disorders in small bowel atresia. 展开更多
关键词 Small bowel atresia Enteric nervous sys-tem Smooth muscle Motility disorder
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Exploring Image Culture Through Narrative: A Study on Jennifer Egan's Twitter Fiction Black Box
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作者 NIE Bao-yu 《Journal of Literature and Art Studies》 2015年第10期820-829,共10页
Notable for the completeness with which it surrenders formally and artistically to the textual dictates of Twitter, Jennifer Egan's 2012 short science fiction Black Box is one of the most triumphant and fully-fledged... Notable for the completeness with which it surrenders formally and artistically to the textual dictates of Twitter, Jennifer Egan's 2012 short science fiction Black Box is one of the most triumphant and fully-fledged fictions written in the form of new media. This paper explores the Twitter narrative employed in Black Box, pointing out that the serialized tweeting format of the story released via computer, mobile phone, or other electronic equipments brings readers immediate reading experience, allowing readers to sense the same feelings as the protagonist does. Through the experimental serialization of"Twitter" narrative, Egan expresses her concerns and worries about the security of the American security as well as the whole world in the post-"9.11" period and at the same time she embraces the virtues and pleasures of traditional storytelling delivered through a wholly new digital format. This paper concludes that Black Box is perhaps one of the boldest experiments of narrative form and is direct exploration into the contemporary image culture. 展开更多
关键词 Jennifer Egan Black Box Twitter narrative image culture
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Arg-X Activity in Trypsin-like Complexes of the Nuclear Rroteins in the Suprastructures of Interphase Chromatin During Induction of Growth Morphogenesis Mature Germs of Wheat
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作者 Ivanova Evilina Vafina Gulnara Ivanov Ruslan Tereshchenko Lidia 《Journal of Life Sciences》 2014年第5期394-398,共5页
The purpose of this study was to analyze spatio-temporal dynamics of localization of protease-sensitive sites Arg-X in non-histone and histone blocks of heteropolymer suprastructures (nucleoplasm, chromatin, nuclear ... The purpose of this study was to analyze spatio-temporal dynamics of localization of protease-sensitive sites Arg-X in non-histone and histone blocks of heteropolymer suprastructures (nucleoplasm, chromatin, nuclear matrix) as possible zones affecting the conformational rearrangements of the total interphase chromatin at the induction of increasing morphogenesis of mature embryos-germs of spring and transformed from its winter wheat. Germinated embryos-germs were detached from endosperm after 24 hours from the start of soaking. Cell nuclei have been allocated from embryos-germs and cleared, and then from their heteropolymer suprastructures (nucleoplasm, chromatin loosely bound with nuclear matrix and chromatin tightly bound with nuclear matrix, and nuclear matrix) were extracted by increasing ionic strength of solution. From isolated nuclear suprastructures, non-histone proteins were separated from histones using ion exchange chromatography. Trypsin-like complexes from non-histone proteins and histone blocks were isolated using the affinity chromatography. The Arg-X (tryptase) activity was assessed by cleavage of Arg-X bonds in the arginine-enriched protein protamine. Hypersensitivity to the Arg-X proteolysis in trypsin-like complexes detected at the level suprastructures of chromatin tightly bound with the nuclear matrix was shown. The most active changes of the nuclear proteome have occurred at the level of the non-histone proteins and the core histones (H2A + H2B) (H3 + H4) of induced to growth embryos-seedlings of winter wheat (compared to the initial spring form of wheat). Perhaps hypersensitivity to the Arg-X activity of the trypsin-like complexes in the non-histone proteins and the core blocks of chromatin tightly bound with nuclear matrix have been entrenched during the transforming of the winter wheat from the initial spring wheat. 展开更多
关键词 Arg-X protease-sensitive trypsin-like complexes non-histones HISTONES supramolecular structures cell nuclei spring and winter wheat.
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Expression of BMP-7 and its receptors in renal tubolo-interstitial fibrosis induced with unilateral ureteral obstruction in rats
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作者 周剑锋 袁发焕 +1 位作者 李娜 张耀全 《Journal of Medical Colleges of PLA(China)》 CAS 2005年第1期12-16,共5页
Objective:To study the changes of the expression of bone morphogenetic protein-7(BMP-7) and its receptors(BMPR-Ⅱ,ALK2,ALK3 and ALK6) in the renal tubulointerstitial fibrosis induced with unilateral ureteral obstructi... Objective:To study the changes of the expression of bone morphogenetic protein-7(BMP-7) and its receptors(BMPR-Ⅱ,ALK2,ALK3 and ALK6) in the renal tubulointerstitial fibrosis induced with unilateral ureteral obstruction in rats. Methods: Sixty Wistar male rats were divided randomly into the normal control,sham-operation and unilateral ureteral obstruction(UUO) groups and the rats were killed on the 1st,3rd,7th and 14th postoperative days respectively.The mRNA level of BMP-7,BMPR-Ⅱ,ALK2,ALK3 and ALK6 was determined with RT-PCR.The site and level of protein expression of BMP-7 were observed with immunohistochemical staining. Results: The mRNA level of BMP-7,BMPR-Ⅱ,ALK2 and ALK3 was significantly decreased in the rats of UUO group than in those of the sham-operation group but the mRNA level of ALK6 showed no obvious changes in all the rats.Immunohistochemical staining revealed that the protein of BMP-7 was mainly expressed in the renal tubules and interstitial tissue of the kidneys in normal rats but it was decreased gradually along with the unilateral ureteral obstruction. Conclusion: It is found that the loss of BMP-7 and its receptors including BMPR-Ⅱ,ALK2 and ALK3 occurs in the early phase of renal tubulointerstitial fibrosis before the appearance of other pathological changes in the kidney and may play an important role in the occurrence and progress of renal tubulointerstitial fibrosis. 展开更多
关键词 bone morphogenetic protein-7 RECEPTOR unilateral ureteral obstruction FIBROSIS
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A buffer insertion and simultaneous sizing timing optimization algorithm
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作者 尹国丽 Lin Zhenghui 《High Technology Letters》 EI CAS 2006年第3期267-271,共5页
A path-based timing optimization algorithm for buffer insertion and simultaneous sizing is proposed. Firstly, candidate buffer insertion location and buffer size for each branch in a given routing path were obtained v... A path-based timing optimization algorithm for buffer insertion and simultaneous sizing is proposed. Firstly, candidate buffer insertion location and buffer size for each branch in a given routing path were obtained via localized timing optimization. Then, through evaluating each potential insertion against design objectives, potential optimal buffer insertion locations and sizes for the whole routing tree were determined. At last, by removing redundant buffer insertion operations which do not maximize S ( so ), given timing requirements are finally fulfilled through minimum number of buffers. 展开更多
关键词 buffer insertion buffer sizing timing optimization binary tree single source
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New findings concerning the Pleistocene Glaciation of the Leh Basin,Ladakh(34°03'N/77°38'E)
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作者 Hermann Achenbach 《Journal of Mountain Science》 SCIE CSCD 2010年第4期367-374,共8页
Like for most parts of High Asia,researches concerning the Pleistocene landscape evolution of the Leh Basin(34°03' N/77°38' E) have also left contradictions.To push this topic,three up to now unexplo... Like for most parts of High Asia,researches concerning the Pleistocene landscape evolution of the Leh Basin(34°03' N/77°38' E) have also left contradictions.To push this topic,three up to now unexplored Ladakh Range tributaries of the Leh Basin(Stagmo-,Arzu-and Nang-Valley) have been investigated.U-shaped profiles,transfluence passes,moraine mantled and glacially rounded peaks and ridges,roches moutonnées,glacial flank polishings and ground moraines document the former glaciation of the study area.The ice fillings of these tributaries reached a minimum thickness up to 540 m.Even at the valley outlets and on the orographic right side of the Leh Basin,the glaciation was more than 350 m thick.Based on these empirically extracted results,theoretical snow line considerations lead to the conclusion that the whole Leh Basin was filled up by a former Indus-Valley glacier.An ice injection limited to the nourishment areas of the Ladakh Range valleys could not have caused the reconstructed ice cover(down to 3236 m a.s.l.),which is proved by extended ground moraine complexes.Only an Indus ice stream network(most likely during the LGP),nourished by inflowing glaciers of the Ladakh-and Stok Range,explains the widespread existence of the glacial sediments at the outlets of the investigated valleys. 展开更多
关键词 Glacial-geomorphology Formerglaciation Last glacial period Equilibrium linealtitude High Asia
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Alice Walker' s Colors of Identity
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作者 Codruta Mirela Stanisoara 《Journal of Literature and Art Studies》 2016年第9期989-995,共7页
The paper traces back women like Celie, Shug, Sofia or Nettie engaged in journeys of self-discovery and development, ones that follow predicted feminist patterns, who try to get free from any dominance, either be it m... The paper traces back women like Celie, Shug, Sofia or Nettie engaged in journeys of self-discovery and development, ones that follow predicted feminist patterns, who try to get free from any dominance, either be it male, social or cultural. The colour purple signifies a metaphysical, social and personal rebirth reflected into different shades by their inner self. The social oppression for black women in their quest for freedom is the main theme of Walker's novel The Color Purple, written in the epistolary technique of Samuel Richardson's in the XVIllth century English novel. In our attempt to analyse the theme and the female characters of the novel we are also trying to cross a bridge from the slave woman of the past belonging to a completely different culture and race to the contemporary paradigm of the liberated woman. The movement in time encompasses possible similitudes and differences. 展开更多
关键词 black women IDENTITY QUEST LETTERS CULTURES
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Research on the Application Security Isolation Model
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作者 Gong Lei Zhao Yong Liao Jianhua 《China Communications》 SCIE CSCD 2010年第6期153-156,共4页
Typical isolation models are studied and a New Application Security Isolation model called NASI is proposed, which is based on trusted computing technology and least privilege principle. This paper introduces the desi... Typical isolation models are studied and a New Application Security Isolation model called NASI is proposed, which is based on trusted computing technology and least privilege principle. This paper introduces the design ideas of NASI, gives out formal description and safety analysis for the model, and finally describes the implementation of prototype system based on NASI. 展开更多
关键词 application isolation security model application security protection
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Inarticulateness, Power and Ethnic identity On Jorge Luis Borges' The Gospel According to Mark
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作者 Du Bingyue 《International Journal of Technology Management》 2016年第8期10-11,共2页
This paper attempts to focus on Jorge Luis Borges’ short story The Gospel according To Mark. Borges, an Argentina short storywriter and translator, whose motherland is under long-term western colonization, identifi e... This paper attempts to focus on Jorge Luis Borges’ short story The Gospel according To Mark. Borges, an Argentina short storywriter and translator, whose motherland is under long-term western colonization, identifi es himself unconsciously with the western culture. Hisworks mostly touch upon the themes of religion and philosophy. Along with post-colonialism theory’s springing up, critics began to analyze hisworks from the post-colonial perspective. The author thinks that this short story with religious implication parallels to the cultural invasion in theperiod of colonization, from powerful culture to weaker one. The author, thus, aims to use Michael Foucault’s viewpoints concerning power andknowledge to probe into the western cultural hegemony and ideological invasion refl ected in this story. Besides, the loss and construction of theethnic identity of the colonized will be discussed in details. 展开更多
关键词 Jorge Luis Borges power and knowledge inarticulateness Ethnic identity cultural hegemony.
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Constructal optimization of cylindrical heat sources with forced convection based on entransy dissipation rate minimization 被引量:12
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作者 GONG ShuWen CHEN LinGen +2 位作者 XIE ZhiHui FENG HuiJun SUN FengRui 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第4期631-639,共9页
Based on constructal theory and entransy theory,the optimal designs of constant-and variable-cross-sectional cylindrical heat sources are carried out by taking dimensionless equivalent resistance minimization as optim... Based on constructal theory and entransy theory,the optimal designs of constant-and variable-cross-sectional cylindrical heat sources are carried out by taking dimensionless equivalent resistance minimization as optimization objective.The effects of the cylindrical height,the cylindrical shape and the ratio of thermal conductivity of the fin to that of the heat source are analyzed.The results show that when the volume of the heat source is fixed,there exists an optimal ratio of the center-to-centre distance of the fin and the heat source to the cylinder radius which leads to the minimum dimensionless equivalent thermal resistance.With the increase in the height of the cylindrical heat source and the ratio of thermal conductivity,the minimum dimensionless equivalent thermal resistance decreases gradually.For the heat source model with inverted variable-cross-sectional cylinder,there exist an optimal ratio of the center-to-centre distance of the fin and the heat source to the cylinder radius and an optimal radius ratio of the smaller and bigger circles of the cylindrical fin which lead to a double minimum dimensionless equivalent thermal resistance.Therefore,the heat transfer performance of the cylindrical heat source is improved by adopting the cylindrical model with variable-cross-section.The optimal constructs of the cylindrical heat source based on the minimizations of dimensionless maximum thermal resistance and dimensionless equivalent thermal resistance are different.When the thermal security is ensured,the optimal construct of the cylindrical heat source based on minimum equivalent thermal resistance can provide a new alternative scheme for the practical design of heat source.The results obtained herein enrich the work of constructal theory and entransy theory in the optimal design field of the heat sources,and they can provide some guidelines for the designs of practical heat source systems. 展开更多
关键词 constructal theory entransy theory entransy dissipation rate minimization three-dimensional cylindrical heat source generalized thermodynamic optimization
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Constructal entransy dissipation rate minimization of a rectangular body with nonuniform heat generation 被引量:8
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作者 FENG HuiJun CHEN LinGen +1 位作者 XIE ZhiHui SUN FengRui 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第9期1352-1359,共8页
Based on construtal theory, a nonuniform heat generation problem in a rectangular body is investigated in this paper. Entransy dissipation rate(EDR) is taken as the optimization objective. The optimal body shapes with... Based on construtal theory, a nonuniform heat generation problem in a rectangular body is investigated in this paper. Entransy dissipation rate(EDR) is taken as the optimization objective. The optimal body shapes with constant and variable widths of the high conductivity channel(HCC) are derived. For the rectangular first order assembly(RFOA) with constant cross-section HCC, the shape of the RFOA and width ratio of the HCCs are optimized, and the double minimum EDR is obtained. The heat transfer performance of the RFOA becomes worse when the nonuniform coefficient increases. For the RFOA with variable cross-section HCC, the EDR of the RFOA can be minimized for four times. Compared the optimal construct based on minimum EDR of the RFOA with that based on minimum maximum temperature difference, the shape of the former optimal construct is tubbier, and the average temperature difference is lower. In the practical design of electronic devices, when the thermal safety is ensured, the constructal design scheme of the former optimal construct can be adopted to improve the global heat transfer performance of an electronic device. 展开更多
关键词 constructal theory entransy theory nonuniform heat generation rectangular body generalized thermodynamic optimization
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Constructal entransy dissipation rate minimization for umbrella-shaped assembly of cylindrical fins 被引量:24
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作者 XIAO QingHua CHEN LinGen SUN FengRui 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第1期211-219,共9页
Umbrella-shaped assembly of cylindrical fins is optimized by adopting analytical method and taking dimensionless mean thermal resistance (MTR) as performance index. The optimal construct of umbrella-shaped assembly is... Umbrella-shaped assembly of cylindrical fins is optimized by adopting analytical method and taking dimensionless mean thermal resistance (MTR) as performance index. The optimal construct of umbrella-shaped assembly is obtained. The results show that the heat conductance performance of the assembly becomes ever worse with ever greater number of elemental cylindrical fins,the umbrella-shaped assembly reduces to cylindrical fin in some values of design parameters,and the diameters’ dependence on design parameters is weak for the optimized assembly. An equivalent thermal resistance defined based on entransy dissipation rate (EDR) reflects an average heat transfer effect of the assembly. The constructal design corresponding to the minimum EDR (or MTR) should be adopted for designing an assembly of fins in engineering at the limit safe condition. 展开更多
关键词 constructal theory FIN entransy dissipation rate intensifying heat transfer generalized thermodynamic optimization
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Constructal entransy dissipation rate minimization for leaf-like fins 被引量:19
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作者 FENG HuiJun CHEN LinGen SUN FengRui 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第2期515-526,共12页
Based on constructal theory,the constructs of the leaf-like fins are optimized by taking minimum entransy dissipation rate(for the fixed total thermal current,i.e.,the equivalent thermal resistance) as optimization ob... Based on constructal theory,the constructs of the leaf-like fins are optimized by taking minimum entransy dissipation rate(for the fixed total thermal current,i.e.,the equivalent thermal resistance) as optimization objective.The optimal constructs of the leaf-like fins with minimum dimensionless equivalent thermal resistance are obtained.The results show that there exists an optimal elemental leaf-like fin number,which leads to an optimal global heat conduction performance of the first order leaf-like fin.The Biot number has little effects on the optimal elemental fin number,optimal ratios of length and width of the elemental and first order leaf-like fins;with the increase of the thermal conductivity ratio of the vein and blade,the optimal elemental fin number and optimal ratio of the length and width of the elemental leaf-like fin increase,and the optimal shape of the first order leaf-like fin becomes tubbier.The optimal construct based on entransy dissipation rate minimization is obviously different from that based on maximum temperature difference minimization.The dimensionless equivalent thermal resistance based on entransy dissipation rate minimization is reduced by 11.54% compared to that based on maximum temperature difference minimization,and the global heat conduction performance of the leaf-like fin is effectively improved.For the same volumes of the elemental and first order leaf-like fins,the minimum dimensionless equivalent thermal resistance of the first order of the leaf-like fin is reduced by 30.10% compared to that of the elemental leaf-like fin,and the global heat conduction performance of the first order leaf-like fin is obviously better than that of the elemental leaf-like fin.Essentially,this is because the temperature gradient field of the first order leaf-like fin based on entransy dissipation rate minimization is more homogenous than that of the elemental leaf-like fin.The dimensionless equivalent thermal resistance defined based on entransy dissipation rate reflects the average heat transfer performance of the leaf-like fin,and can provide some guidelines for the thermal design of the fins from the viewpoint of heat transfer optimization. 展开更多
关键词 constructal theory entransy dissipation rate leaf-like fin heat transfer optimization generalized thermodynamic optimization
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