检索结果-南通市图书馆

China Report ASEAN 2021年第5期6卷 48-49页

作者： Xin Lida Long wa 不详

As traditional retail was pummeled by the COVID-19 pandemic,retailers were forced to accelerate integration of online and offline *** Jian,CEO of iClick Interactive,a solution provider for digital business operations,has been urging retail companies,service providers,and business platforms to keep pace with the transformation as COVID-19 prevention and control measures become normalized and profound changes take place in business operations and consumer *** quality of the growth of the digital economy is improving rapidly,and business activities including transactions and customer communication with sellers have transformed into data records.

关键词： companies operations prevention

Sol-gel Template Synthesis and Photoluminescence Properties of (Pb_(0.5)Sr_(0.5))TiO_(3) Nanotube Arrays

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第7期28卷 278-281页

作者： JIANg Yan-Ping wa.g Yu CHAN Lai wa Helen TANg Xin-gui ZHOU Yi-Chun Key Laboratory of Low-Dimensional Materials and Application Technology Xiangtan UniversityXiangtan 411105 Department of Applied Physics and Materials Research Centre Hong Kong Polytechnic UniversityHung HomKowloonHong KongChina School of Physics&Optoelectric Engineering and Guangzhou Higher Education Mega CenterGuangdong University of TechnologyGuangzhou 510006

Lead strontium titanate(Pb_(0.5)Sr_(0.5))TiO_(3)(PST)nanotube arrays are prepared by a sol-gel and spin-coating process using an anodic aluminium oxide *** structure and morphology of the as-prepared sample are characterized by x-ray diffraction,scanning electron microscopy and transmission electron *** results show that the as-prepared PST sample possesses a perovskite structure with a relatively uniform diameter of about 200 ***(PL)spectrum of the sample shows emission bands centered at about 2.87 eV at room temperature,which consists of three intense emission sub-bands at 3.02,2.87 and 2.76 eV,*** energy corresponding to the central PL peak is lower than the band-gap energy(3.2 eV)of PST bulk materials,which may originate from the size effect of the PST nanotube *** multi-peaks in the PL spectrum may be attributed to the radiative recombination of trapped electrons and holes in tail and gap states induced by local defect and oxygen *** Raman scattering spectrum of the PST nanotube arrays,which are obviously broadened in comparison with the bulk materials,show that their phonon modes are in agreement with those allowed in the tetragonal phase.

关键词： template perovskite bands

Application of high-pressure technology in exploring mechanical properties of high-entropy alloys

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tungsten 2023年第1期5卷 50-66页

作者： Shu-Cong Li Qing-Lin wa.g Yu Yao Dan-Dan Sang Hai-wa Zhang guo-Zhao Zhang Cong wa.g Cai-Long Liu Shandong Key Laboratory of Optical Communication Science and Technology School of Physics Science&Information TechnologyLiaocheng UniversityLiaocheng 252059China College of Mathematics and Physics Beijing University of Chemical TechnologyBeijing 100029China

In recent years,high-entropy alloys(HEAs) have developed a lot as the new style of materials,which have become a research focus in the materials *** breaks the normal procedure of traditional alloy design(based on one/two elements as the main component,and adds some other elements to improve the micro structure and required related performance of the alloy),and consists of five or more equal or nearly equal elements,with multiple principal ***,HEAs have many excellent mechanical properties compared with traditional alloys,which have aroused great research interest of *** rapid development of high-pressure technology makes it a powerful tool to modulate the structures of HEAs,and brings new chance for the study and optimization of mechanical properties of *** this paper,the application of high-pressure technology in exploring and improving the mechanical properties of HEAs is reviewed,which could deepen the understanding of high-pressure technology and provide a new avenue for further exploration of HEAs’ mechanical properties.

关键词： High-entropy alloys Mechanical properties High-pressure torsion High-pressure Diamond anvil cells

Copper-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides withβ-trifluoromethyl-substituted alkenyl heteroarenes

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2023年第11期66卷 3193-3204页

作者： Xiang Cheng Xin Chang Yuhong Yang Zongpeng Zhang Jing Li Yipu Li Wenxiao Zhao Lung wa Chung Huailong Teng Xiu-Qin Dong Chun-Jiang wa.g College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryShanghai 230021China Shenzhen grubbs Institute Department of Chemistry and Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhen 518055China College of Science Huazhong Agricultural UniversityWuhan 430070China

Copper-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides andβ-trifluoromethyl-substituted alkenyl heteroarenes was developed for the first time.A wide range of enantioenriched pyrrolidines containing both heteroarenes and trifluoromethyl group with multiple stereogenic centers could be readily accessible by this method with good to high yields and excellent levels of both stereo-and regioselectivity(up to 99%yield,>20:1 rr,>20:1 dr,and up to 95%ee).Notably,substratecontrolled umpolung-type dipolar cycloaddition was also disclosed in this protocol to achieve regiodivergent synthesis withα-aryl substituted aldimine esters as the dipole *** DFT studies were conducted to explore the origin of the stereo-and regioselectivity of this 1,3-dipolar cycloaddition,and suggest that copper(Ⅱ)salt utilized in this catalytic system could be reduced in-situ to the active copper(Ⅰ)species and might be responsible for the observed high stereo-and regioselectivity.

关键词： asymmetric catalysis 1 3-dipolar cycloaddition chiral pyrrolidines heteroarene trifluoromethyl group

在线全文

学校读者我要写书评

暂无评论

试论地质学者的地震理念

地震地质 2008年第1期30卷 305-323页

作者：江娃利中国地震局地壳应力研究所北京100085

地质学者认为断层是震源在地表的表现。在这一理念的基础上,文中讨论了如何通过活断层定量研究开展强震预测。强震地点预测的依据是断层活动性调查。在这方面强调航片判读和野外断层地形学的调查,由此获取断裂带的最新活动时期。对于确... 详细信息

地质学者认为断层是震源在地表的表现。在这一理念的基础上,文中讨论了如何通过活断层定量研究开展强震预测。强震地点预测的依据是断层活动性调查。在这方面强调航片判读和野外断层地形学的调查,由此获取断裂带的最新活动时期。对于确认的晚第四纪以来活动的断裂带,认为其将来具有发生强震的潜势。强震的活动强度从调查活断层的长度和同震位移入手。全球大量的历史地震和现今地震表明,断层长度与地震震级之间、以及同震位移与地震震级之间存在正比例关系。有关强震时间的预测,需要获知各条断裂带的强震间隔和最新活动的离逝时间。尽管通过断层的活动速率和同震位移的比值可获取断裂带的强震平均间隔,但通过探槽调查获取古地震活动的年代对分辨各条断裂带强震活动的个性特征仍十分重要。文中多处引用了日本活断层研究的资料和松田?彦教授的认识。最后简要回顾了中国活断层研究过程中的几个重要事件。

关键词：活断层成因定量预测

A compact electro-absorption modulator based on graphene photonic crystal fiber

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第3期29卷 238-244页

作者： guangwei Fu Ying wa.g Bilin wa.g Kaili Yang Xiaoyu wa.g Xinghu Fu wa Jin Weihong Bi School of Information Science and Engineering Key Laboratory for Special Fiber and Fiber Sensor of Hebei ProvinceYanshan UniversityQinhuangdao 066004China

A compact electro-absorption modulator based on graphene photonic crystal fiber is proposed. To enhance the graphene–light interaction efficiency, the innermost six air-holes of photonic crystal fiber are replaced by two large semicircular holes, and monolayer graphene is deposited on the two large semicircular holes. By optimizing the structure parameters, a strong graphene–light interaction is obtained. Moreover, the switch on–off point of the modulator is unchangeable,which is only related to the frequency of the incident light. The influence factors of this composite structure have been analyzed. The proposed modulator is compared with other graphene-based modulators, and the results show that it is filled without dielectric spacer. There are some excellent performances, such as an extinction ratio 7 dB of y-polarization mode,3-dB modulation bandwidth of 70 gHz with small footprint of 205 μm, and a consumption of energy per bit 59 pJ/bit.

关键词： graphene electro-absorption modulator finite element method

在线全文

学校读者我要写书评

暂无评论

有关1976年唐山地震发震断层的讨论

地震地质 2006年第2期28卷 312-318页

作者：江娃利中国地震局地壳应力研究所北京100085

对《地震地质》刊登的两篇文章中有关唐山断裂是高角度西倾的逆冲走滑断裂及唐山市东侧付庄-西河断裂是唐山地震的发震断裂的观点进行讨论。笔者认为,如果唐山地震断层是西倾的逆冲走滑活动,需要考虑唐山逆冲断裂的活动方式与唐山市西... 详细信息

对《地震地质》刊登的两篇文章中有关唐山断裂是高角度西倾的逆冲走滑断裂及唐山市东侧付庄-西河断裂是唐山地震的发震断裂的观点进行讨论。笔者认为,如果唐山地震断层是西倾的逆冲走滑活动,需要考虑唐山逆冲断裂的活动方式与唐山市西侧第四纪凹陷之间的关系;如果付庄-西河断裂是唐山地震震源构造的地表破裂,需要解释该西倾的倾滑断裂带与唐山市内走滑地裂缝带的成因联系。此外,还需要更有说服力的证据排除该地表破裂带是次生构造破裂的可能。建议对控制草泊第四纪凹陷的活动断裂开展调查。

关键词：发震断层唐山地震第四纪凹陷次生构造破裂

Expression of a novel alternative transcript of the novel retinal pigment epithelial cell gene NORPEg in human testes

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2005年第3期7卷 277-288,页

作者： wa Yuan Ying Zheng Ran Huo Li Lu Xiao-Yan Huang Lan-Lan Yin Jian-Min Li Zuo-Min Zhou Jia-Hao Sha Key Laboratory of Reproductive Medicine Department of Histology and Embroyology Nanjing Medical University Nanjing 210029 China

Aim： To identify a novel alternative transcript of the novel retinal pigment epithelial cell gene （NORPEg） expressed in the human testis. Methods： A human testis cDNA microarray was established and hybridized with cDNA probes from human fetal testes, adult testes and human spermatozoa. Differentially expressed clones were sequenced and analyzed. One of these clones was a short transcript of NORPEg which we proceeded to analyze by RT-PCR. Results： The novel short alternative transcript of NORPEg was isolated and named sNORPEg. It was 3486 bp in length and contained a 2952-bp open reading frame, encoding a 110.4-kDa protein of 983 amino acids. Amino acid sequence analysis showed that the sNORPEg protein contains six ankyrin repeats and two coiled-coil domains. It shares a high homology with the NORPEg and ankycorbin proteins in both its sequence and motifs. Blasting the human genome database localized sNORPEg to human chromosome 5pl 3.2-13.3. Expression profiles showed that sNORPEg was expressed in human fetal testes, adult testes and spermatozoa. Moreover, sNORPEg was found to be ubiquitously expressed in human tissues. Conclusion： sNORPEg is expressed in different developmental stages of the testis and encodes a protein that may have roles in human testis development and spermatogenesis. （Asian J Androl 2005 Sep; 7： 277-288）

关键词： alternative transcript NORPEg testis development spermatogenesis

Deuterium distribution and behavior of blisters in pre-damaged and undamaged tungsten

在线全文

学校读者我要写书评

暂无评论

Tungsten 2024年第3期6卷 647-656页

作者： Cong Li Xiao-wa wa.g Ran-Ran Su Xuan-Xin Hu Shu-guang Wei Han-Jun Tu Li-Qun Shi Hong-Liang Zhang Key Laboratory of Nuclear Physics and Ion-Beam Application Institute of Modern PhysicsFudan UniversityShanghai 200433China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Materials Science and Engineering University of WisconsinMadison WI 53706USA

Tungsten(W),as a plasma-facing material,is subjected to high fluence plasma,resulting in both radiation damage and deuterium(D)*** study explores the blistering behavior and D supersaturated layers in both pre-damaged and undamaged W *** achieve a uniform damage profile similar to neutron irradiation,carbon(C)ions with multiple energies and angles were *** samples were further irradiated with low-energy D ions under two fluences at temperatures from~380 to 640 *** various experimental techniques,we found that pre-damaged W samples can effectively suppress the formation of blistering and lower the threshold temperature at which the surface remains free of *** also observed the prominent D supersaturated peaks within the depth of 20 nm in both pre-damaged and undamaged ***,a close correlation between blistering and the D supersaturation was *** results suggest that neutron irradiation in the fusion reactors could increase the critical D concentration for blistering,while a greater depth of damage facilitated the inward diffusion of D,thereby reducing the D concentration gradient and alleviating surface blistering.

关键词： Tungsten Deuterium Supersaturated layer Blister Ion irradiation Pre-damage

在线全文

学校读者我要写书评

暂无评论

ob基因型对小鼠早期发育的影响

中华预防医学杂志 2000年第6期34卷 345-347页

作者：徐培渝 Truett gE walker wa 华西医科大学公共卫生学院毒理学教研室 610041 美国路易斯安娜州立大学Penington医学研究中心

目的　探讨ob基因对早期发育的影响及其在发育早期的显性程度。方法　用聚合酶链反应和限制性内切酶法检测C5 7BL/ 6Job小鼠的 3种基因型 :野生型 (+ / + )、杂合体型 (ob/ + )及突变型 (ob/ob)。记录小鼠出生 4d～ 2个月的体重。比较... 详细信息

目的　探讨ob基因对早期发育的影响及其在发育早期的显性程度。方法　用聚合酶链反应和限制性内切酶法检测C5 7BL/ 6Job小鼠的 3种基因型 :野生型 (+ / + )、杂合体型 (ob/ + )及突变型 (ob/ob)。记录小鼠出生 4d～ 2个月的体重。比较出生后 7、14和 2 4d小鼠的腹股沟白色脂肪(waT)和背肩岬的褐色脂肪 (BAT)湿重。结果　小鼠出生 2周后 ,ob/ob小鼠体重快速增长 ,7周时已是 + / +和ob/ +小鼠体重的 2倍 ;2 4d时的waT明显高于 + / +和ob/ +小鼠。ob基因型对BAT的影响早于waT。ob/ +小鼠的体重和waT均介于 + / +小鼠和ob/ob小鼠之间。 2周以前 ,ob基因对体重影响的显性指数在 1 0～ 0 5之间 ,表现为共显性 ,6周时 ,显性指数接近 0 0 ,几乎为完全隐性。结论　ob基因型对体重和waT的影响始于第 2周后 ;

关键词：基因型体重肥胖症小鼠,肥胖