检索结果-南通市图书馆

川西地区退耕还林工程及其对农村经济发展的影响

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

山地学报 2002年第4期20卷 438-444页

作者：林波刘庆游翔庞学勇中国科学院成都生物研究所中国科学院、水利部成都山地灾害与环境研究所四川农业大学农学院四川成都610041 四川雅安400047

四川省西部地区是全国退耕还林 (草 )试点示范工程的重点地区。由于区内人地矛盾突出 ,随着退耕还林工程的实施 ,造成了该地区林农、林牧、农牧关系紧张 ,阻碍了当地退耕还林工程的实施和农村经济的发展。本文通过实地走访、问卷调查、... 详细信息

四川省西部地区是全国退耕还林 (草 )试点示范工程的重点地区。由于区内人地矛盾突出 ,随着退耕还林工程的实施 ,造成了该地区林农、林牧、农牧关系紧张 ,阻碍了当地退耕还林工程的实施和农村经济的发展。本文通过实地走访、问卷调查、座谈等形式 ,对川西地区退耕还林工程的实施现状、进展、困难、相关政策和技术应用情况等进行了初步考察 ,并分析了退耕还林工程的实施对川西地区农村经济带来的影响 :退耕还林后 ,川西地区农业 (种植业 )产值相对降低 ,林业和牧业产值逐渐增加 ,但变化幅度不大 ,表明退耕还林工程的实施在短期内并未给川西农村经济带来多大的变化 ,但从长远来看 ,这种影响又是深远的。因而退耕还林工程中强调生态效应的同时 ,如何将农村长期经济效应向短期化转化以及长期生态效应向经济化转化是个值得研究的问题

关键词：退耕还林农村经济川西地区

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于A-Frame的博物馆漫游系统设计

软件 2018年第9期39卷 51-54页

作者：张柏林刘华清尹猛韩佳坤山东农业大学信息科学与工程学院大数据研究中心山东泰安271018

虚拟现实技术应用在博物馆藏品展示中,使用户能够通过佩戴虚拟现实设备,实现在虚拟场景中参观博物馆内部场景,与展品"零距离"接触。基于A-Frame框架,结合3DMax建模工具开发虚拟漫游系统,从而能够高度还原泰安市博物馆中的部分展品。用... 详细信息

虚拟现实技术应用在博物馆藏品展示中,使用户能够通过佩戴虚拟现实设备,实现在虚拟场景中参观博物馆内部场景,与展品"零距离"接触。基于A-Frame框架,结合3DMax建模工具开发虚拟漫游系统,从而能够高度还原泰安市博物馆中的部分展品。用户可在任何地点通过浏览器对博物馆进行虚拟漫游,身临其境获取馆内藏品信息。

关键词： A-Frame WebVR 3DMax 博物馆漫游

双源CT冠脉成像在冠脉粥样硬化性狭窄诊断中的价值研究

在线全文

学校读者我要写书评

暂无评论

现代生物医学进展 2017年第20期17卷 3969-3972页

作者：林豪肖波刘一江张昊魏飞达州市中西医结合医院CT室四川迭州635000 川北医学院附属医院放射科四川南充637000 达州市中西医结合医院心内科四川达州635000

目的:分析双源CT冠脉成像在冠脉粥样硬化性狭窄诊断中的价值。方法:以2014年5月至2016年5月我院初诊为"冠心病"的100例患者为研究对象,所有患者均行冠状动脉造影(CAG)和双源CT(DSCT)检查,比较两种检查方法在冠脉粥样硬化性显著性狭窄患... 详细信息

目的:分析双源CT冠脉成像在冠脉粥样硬化性狭窄诊断中的价值。方法:以2014年5月至2016年5月我院初诊为"冠心病"的100例患者为研究对象,所有患者均行冠状动脉造影(CAG)和双源CT(DSCT)检查,比较两种检查方法在冠脉粥样硬化性显著性狭窄患者和不同冠脉血管(右冠脉、左冠脉主干、左前降支和回旋支)狭窄中的检查结果。结果:常规CAG检查共发现35例患者存在冠状动脉显著性狭窄,检出率为35%。DSCT共检出冠状动脉显著性狭窄患者45例,敏感度、特异度、阳性预测值和阴性预测值分别为100.0%,84.61%,77.78%和100.0%。一致性分析结果显示两种检测方法结果存在较强一致性,kappa=0.794(P<0.05)。100例患者中,常规CAG检查共发现显著性狭窄血管47条。DSCT共检出显著性狭窄血管39条,敏感度、特异度、阳性预测值和阴性预测值分别为93.62%、92.92%、63.77%和99.10%。一致性分析结果显示两种检测方法存在较强一致性,kappa=0.719(P<0.05)。右冠脉、左冠脉主干、左前降支和回旋支中,检查特异度和阴性预测值以左冠脉主干最高,敏感度和阳性预测值以左前降支最高。DSCT检查对于冠脉血管的完全闭塞、重度狭窄、中度狭窄和轻度狭窄的显示率高于CAG检查,但差异均无统计学意义(P<0.05)。结论:DSCT检查在冠脉粥样硬化显著性狭窄患者和狭窄冠脉血管(右冠脉、左冠脉主干、左前降支和回旋支)中具有较高的诊断价值。

关键词：冠状动脉狭窄冠状动脉造影双源CT冠脉成像

多力场耦合条件下T型圆管通道内流体热混合机理研究

在线全文

学校读者我要写书评

暂无评论

西安交通大学学报 2025年第1期59卷 78-92页

作者：李桉琦苏博林梅王秋旺西安交通大学能源与动力工程学院西安710049

针对海洋动力平台和船舶动力装置中T型圆管通道内冷热流体间的热混合机理尚不清楚的问题,利用大涡模拟方法,对不同支管布置方式高温高压工况下(运行压力为10 MPa,进口流体温差为275 K,摇摆雷诺数为41 500)的多力场耦合T型圆管通道内流... 详细信息

针对海洋动力平台和船舶动力装置中T型圆管通道内冷热流体间的热混合机理尚不清楚的问题,利用大涡模拟方法,对不同支管布置方式高温高压工况下(运行压力为10 MPa,进口流体温差为275 K,摇摆雷诺数为41 500)的多力场耦合T型圆管通道内流体热混合机理进行数值研究。利用提出的混合系数定量评价了不同布置方式下T型圆管通道内流体混合效果,利用均方根温度定量评价了不同布置方式下T型圆管通道管壁处温度脉动情况。结果表明:剪切层和尾迹区内涡结构与温度场存在时间和空间上的协同机制,且涡脱落频率和温度脉动频率基本相同,脱落频率为19.3 Hz;附加惯性力引起T型圆管通道内涡结构和温度场在时间和空间上周期性变化,加速了流体混合过程,削弱了浮升力和重力引起的热分层现象,同时增大了流体域内温度波动,长度约为10.2 D(D为主管内径);与对应的静止工况相比,支管竖直向上、水平和竖直向下布置时,摇摆条件下混合系数分别增大了10.8%、18.3%和27.8%;摇摆条件竖直向下布置时,管壁处温度均方根峰值最大为0.16,约为静止工况的2倍。因此,支管竖直向上布置时,热混合效果最好,热分层现象最弱,在实际应用中应被优先考虑。

关键词： T型圆管通道浮升力摇摆条件热混合机理大涡模拟

同方期刊数据库

Experimental observations of ferroelectricity in double pyrochlore Dy2Ru2O7

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2014年第1期9卷 82-89页

作者： Zai-Chun Xu Mei-Feng liu lin lin Huimei liu Zhi-bo Yan Jun-Ming liu Laboratory of Solid State Microstructures Nanjing University Nanjing 210093 China

Double pyrochlore Dy2Ru207 is synthesized and its magnetism and ferroelectricity below the Ru4＋ spin ordering temperature （NI00 K） are investigated. The ferroelectric transition appears at -18 K, much higher than the Dy3＋ spin ordering point at -1.8 K and lower than the Ru4＋ spin ordering point at -100 K. The measured electric polarization at ,-2 K is as big as 145℃/m2 in the polycrystalline samples. It is argued that the ferroelectricity is possibly ascribed to the electric dipole ordering arising from the collective monopole excitations in the Dy3＋ tetrahedrons in prior to the Dy3＋ spin ordering into spin-ice like state below -1.8 K.

关键词： pyrochlore oxides multiferroics magnetically induced ferroelectricity

Polyoxovanadate ionic crystals with open tunnels stabilized by macrocations for lithium-ion storage

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第7期16卷 9267-9272页

作者： Jie Wang lin Wang Congyan liu Yan Wang Fei Ye Wen Yan bo liu School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026China

Polyoxometalates(POMs)with multiple redox active sites have been reported as charge sponge for lithium-ion batteries(LIBs).Herein,we for the first time introduce a polyoxovanadate(POV)ionic crystals with macrocations,[Ni(Phen)_(3)][ClV_(14)O_(34)]Cl(NiV_(14),Phen=1,10-phenanthroline),as an anode material for *** existence of macrocation[Ni(Phen)_(3)]^(2+)stabilizes the open tunnels inside NiV_(14).The NiV_(14)electrode exhibits superior rate capabilities(1083 mAh·g^(-1)at 100 mA·g^(-1)and 384 mAh·g^(-1)at 2000 mA·g^(-1))due to the rapid capacitive dominated contribution and high Li^(+)ions diffusion coefficients(3.3×10^(-12) cm^(-2)·s^(-1)),and it delivers a remarkable cycling stability with a Coulombic efficiency of 99.7%after 1000 cycles at 2000 mA·g^(-1).Such performance can be attributed to the stable structure of NiV14 and the highly reversible valence changes of vanadium during the charge/discharge processes,which are revealed by a combination of in situ X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and X-ray absorption fine structure(XAFS)*** work not only demonstrates that NiV_(14) with open tunnels stabilized by macrocation is a promising anode material for high performance LIBs,but also provides important references for the rational design of POMs electrode materials in advanced energy storage systems.

关键词： polyoxometalates(POMs) ionic crystals lithium-ion battery(LIB) macrocation energy storage mechanism

Interconnections between diabetic corneal neuropathy and diabetic retinopathy:diagnostic and therapeutic implications

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

Neural Regeneration Research 2025年第8期20卷 2169-2180页

作者： Mingyi Yu Faith Teo En Ning Chang liu Yu-Chi liu Tissue Engineering and Stem Cell Group Singapore Eye Research InstituteSingapore Yong Loo lin School of Medicine National University of SingaporeSingapore Department of Cornea and External Eye Disease Singapore National Eye CenterSingapore Ophthalmology and Visual Sciences Academic Clinical Program Duke-NUS Medical SchoolSingapore

Diabetic corneal neuropathy and diabetic retinopathy are ocular complications occurring in the context of diabetes *** corneal neuropathy refers to the progressive damage of corneal *** retinopathy has traditionally been considered as damage to the retinal ***,growing evidence suggests that diabetic retinopathy is a complex neurovascular disorder resulting from dysfunction of the neurovascular unit,which includes both the retinal vascular structures and neural *** retinopathy is one of the leading causes of blindness and is frequently screened for as part of diabetic ocular ***,diabetic corneal neuropathy is commonly overlooked and underdiagnosed,leading to severe ocular surface *** studies have found that these two conditions tend to occur together,and they share similarities in their pathogenesis pathways,being triggered by a status of chronic *** review aims to discuss the interconnection between diabetic corneal neuropathy and diabetic retinopathy,whether diabetic corneal neuropathy precedes diabetic retinopathy,as well as the relation between the stage of diabetic retinopathy and the severity of corneal *** also endeavor to explore the relevance of a corneal screening in diabetic eyes and the possibility of using corneal nerve measurements to monitor the progression of diabetic retinopathy.

关键词： cornea corneal nerves diabetes diabetic corneal neuropathy diabetic retinopathy retina

Preparation of In_2O_3-Sr_2RuErO_6 Composite Ceramics by the Spark Plasma Sintering and Their Thermoelectric Performance

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第12期27卷 1165-1168页

作者： bo Cheng Yuanhua lin Jinle Lan Yong liu Cewen Nan State Key Laboratory of New Ceramics and Fine Processing Department of Materials Science and Engineering Tsinghua University Beijing 100084 China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 Ch.ina

Inl.9aZn0.03Ge0.0303 and Sr2RuEr06 composite ceramics have been prepared by the spark plasma sintering （SPS） technique. Microstructure studies show that the Sr2RuErO6 phases are randomly dispersed in the In1.94Zn0.03Ge0.03O3 matrix. The results show that the Seebeck coefficient increases with increasing the amount of Sr2RuErO6, while the thermal conductivity of the composite samples is lower than that of the Inl.9aZno.03Ge0.03O3 ceramic. The thermal conductivity of the 7 vol.% Sr2RuErO6 sample can decrease to 2.15 W.m-1.K-1 at 973 K, and the evaluated maximum ZT value is 0.23 for 3 vol.% Sr2RuErO6 samples at 973 K, which makes them promising materials for the thermoelectric devices.

关键词： Indium oxide Double perovskite Thermoelectric performance Composite

Designing a Phthalonitrile/Benzoxazine Blend for the Advanced GFRP Composite Materials

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2018年第1期36卷 106-112页

作者： Xu-lin Yang Kui Li Ming-Zhen Xu Xiao-bo liu Research Branch of Functional Materials Institute of Microelectronic & Solid State Electronic University of Electronic Science and Technology of China

High performance resin must be used in the high performance glass fiber-reinforced plastic（GFRP） composites, but it is sometimes difficult to balance the processabilities and the final properties in the design of advanced thermoset GFRP composites. In this study, a phthalonitrile/benzoxazine（PPN/BZ） blend with excellent processability has been designed and applied in the GFRP composite materials. PPN/BZ blend with good solubility, low melt viscosity, appropriate gel condition and low-temperature curing behavior could enable their GFRP composite preparation with the prepreg-laminate method under a relatively mild condition. The resulted PPN/BZ GFRP composites exhibit excellent mechanical properties with flexural strength over 700 MPa and flexural modulus more than 19 GPa. Fracture surface morphologies of the PPN/BZ GFRP composites show that the interfacial adhesion between resin and GF is improved. The temperatures at weight loss 5%（T_（5%）） and char residue at 800 °C of all PPN/BZ GFRP composites are over 435 °C and 65% respectively. PPN/BZ GFRP composites with high performance characteristics may find applications under some critical circumstances with requirements of high mechanical properties and high service temperatures.

关键词： Phthalonitrile Benzoxazine High performance composite GFRP composites