期刊文献+
共找到857篇文章
< 1 2 43 >
每页显示 20 50 100
利用GPS对磁暴期间极区TEC变化与极区碎片(Polar Patches)的研究 被引量:13
1
作者 孟泱 王泽民 +1 位作者 鄂栋臣 蔡红涛 《地球物理学报》 SCIE EI CSCD 北大核心 2008年第1期17-24,共8页
利用2004年11月6-10日磁暴发生期间南极区域内的中国中山站GPS常年跟踪站(ZHON)和国际GPS服务站(CAS1,MCM4,SYOG,MAW1)的GPS观测数据,计算了可观测卫星传播路径上的TEC和ROT值,进而依据TEC的波动频率和幅度推估出极区碎片的个数,分... 利用2004年11月6-10日磁暴发生期间南极区域内的中国中山站GPS常年跟踪站(ZHON)和国际GPS服务站(CAS1,MCM4,SYOG,MAW1)的GPS观测数据,计算了可观测卫星传播路径上的TEC和ROT值,进而依据TEC的波动频率和幅度推估出极区碎片的个数,分析了极区磁暴期间电离层响应及其极区碎片特性.最终所得TEC和ROT结果与极区地磁场Dst和Kp指数信息相吻合,如实地反映了磁暴事件和极区碎片的出现.本文所做工作在国内尚未开展,因此所用方法和结论为将来这一方向的研究提供了一定的参考. 展开更多
关键词 磁暴 极区碎片(polar patches) GPS TEC ROT
在线阅读 下载PDF
弓形虫复合粘膜疫苗滴鼻免疫小鼠诱导的Peyer's patches持续性细胞免疫应答 被引量:2
2
作者 孟晓丽 殷国荣 +3 位作者 张建红 刘红丽 申金雁 李珀 《中国病原生物学杂志》 CSCD 2008年第1期27-30,共4页
目的以可溶性速殖子抗原(soluble tachyzoite antigen,STAg)和霍乱毒素(choleratoxin,CT)佐剂制备的弓形虫复合粘膜疫苗滴鼻免疫小鼠,观察肠粘膜诱导部位Peyer’s patches(PP)的细胞免疫应答及持续时间,探讨其免疫机制。方法B... 目的以可溶性速殖子抗原(soluble tachyzoite antigen,STAg)和霍乱毒素(choleratoxin,CT)佐剂制备的弓形虫复合粘膜疫苗滴鼻免疫小鼠,观察肠粘膜诱导部位Peyer’s patches(PP)的细胞免疫应答及持续时间,探讨其免疫机制。方法BALB/c小鼠96只,随机分为实验组和对照组,实验组以STAg(20μg/只)为抗原,CT(1/μg/只)为佐剂滴鼻免疫,对照组PBS滴鼻。滴鼻2次(间隔2周)后,每组6只小鼠分别于第1、2、3、4、6、8、10、12周处死。计数PP个数,制备PP淋巴细胞悬液,计数并涂片;免疫细胞化学法检测CD4^+、CD8^+T细胞亚群。结果实验期间两组小鼠PP数目均无明显变化;实验组免疫后PP淋巴细胞数量明显增生,第2周达高峰,第1、2、3周显著高于对照组(P〈0.05),其中以CD4^+T细胞增生为主,第1周~第8周高于对照组(P〈0.01),CD8^+T细胞第1周~第4周显著增高(P〈0.01),CD4^+/CD8^+比值无显著变化(P〉0.05)。结论弓形虫复合粘膜疫苗滴鼻免疫BALB/c小鼠可有效诱导肠PP部位持续性的免疫应答,从而激活肠粘膜效应部位淋巴细胞的抗弓形虫感染作用。 展开更多
关键词 弓形虫 粘膜疫苗 滴鼻免疫 可溶性速殖子抗原 霍乱毒素 Peyer’s patches
暂未订购
A statistical survey of polar cap cold and hot patches in the Southern Hemisphere using a DMSP Satellite
3
作者 Duan Zhang QingHe Zhang +11 位作者 Kjellmar Oksavik ZanYang Xing LRLyons HuiGen Yang Tong Xu Marc Hairston XiangYu Wang YuZhang Ma GuoJun Li Yong Wang Sheng Lu Jin Wang 《Earth and Planetary Physics》 2025年第4期955-965,共11页
This paper is a statistical survey of Southern Hemisphere cold and hot polar cap patches,in relation to the interplanetary magnetic field(IMF)and ionospheric convection geometry.A total of 11,946 patch events were ide... This paper is a statistical survey of Southern Hemisphere cold and hot polar cap patches,in relation to the interplanetary magnetic field(IMF)and ionospheric convection geometry.A total of 11,946 patch events were identified by Defense Meteorological Satellite Program(DMSP)F16 during the years 2011 to 2022.A temperature ratio of ion/electron temperature(T_(i)/T_(e))<0.68 is recommended to define a hot patch in the Southern Hemisphere,otherwise it is defined as a cold patch.The cold and hot patches have different dependencies on IMF clock angle,while their dependencies on IMF cone angle are similar.Both cold and hot patches appear most often on the duskside,and the distribution of cold patches gradually decreases from the dayside to the nightside,while hot patches have a higher occurrence rate near 14 and 21 magnetic local time(MLT).Moreover,we compared the key plasma characteristics of polar cap cold and hot patches in the Southern and Northern Hemispheres.The intensity of the duskside upward field-aligned current of patches in the Southern Hemisphere(SH)is stronger than that in the Northern Hemisphere(SH),which may be due to the discrepancy in conductivities between the two hemispheres,caused by the tilted dipole.In both hemispheres,the downward soft-electron energy flux of the dawnside patches is significantly greater than that of the duskside patches. 展开更多
关键词 polar ionosphere polar cap patch IRREGULARITIES statistical survey southern hemisphere.
在线阅读 下载PDF
Zingiber cassumunar blended patches for skin application:Formulation,physicochemical properties,and in vitro studies 被引量:1
4
作者 Jirapornchai Suksaeree Laksana Charoenchai +4 位作者 Fameera Madaka Chaowalit Monton Apirak Sakunpak Tossaton Charoonratana Wiwat Pichayakorn 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2015年第4期341-349,共9页
Our work was to study the preparation,physicochemical characterization,and in vitro characteristic of Zingiber cassumunar blended patches.The Z.cassumunar blended patches incorporating Z.cassumunar Roxb.also known as ... Our work was to study the preparation,physicochemical characterization,and in vitro characteristic of Zingiber cassumunar blended patches.The Z.cassumunar blended patches incorporating Z.cassumunar Roxb.also known as Plai were prepared from chitosan and polyvinyl alcohol with glycerin as plasticizer.They were prepared by adding all ingredients in a beaker and homogeneously mixing them.Then,they were transferred into Petri-dish and dried in hot air oven.The hydrophilic nature of the Z.cassumunar blended patches was confirmed by the moisture uptake,swelling ratio,erosion,and porosity values.The FTIR,DSC,XRD,and SEM studies showed revealed blended patches with amorphous region that was homogeneously smooth and compact in both surface and cross section dimensions.They exhibited controlled the release behavior of(E)-4-(30,40-dimethoxyphenyl)but-3-en-lol(compound D)that is the main active compound in Z.cassumunar for anti-inflammation activity.However,in in vitro skin permeation study,the compound D was accumulated in newborn pig skin more than in the receptor medium.Thus,the blended patches showed the suitable entrapment and controlled release of compound D.Accordingly,we have demonstrated that such chitosan and polyvinyl alcohol formulated patches might be developed for medical use. 展开更多
关键词 CHITOSAN Polyvinyl alcohol Z.cassumunar patches Blended patches Skin application
在线阅读 下载PDF
Research Progress of Transdermal Patches in Veterinary Drug Preparations
5
作者 曹允 《Agricultural Science & Technology》 CAS 2017年第8期1470-1473,共4页
With the development of pharmaceutics and other disciplines theories and advanced technologies, the application of many new drug delivery systems has gradually increased in clinical veterinary. Among the many drug del... With the development of pharmaceutics and other disciplines theories and advanced technologies, the application of many new drug delivery systems has gradually increased in clinical veterinary. Among the many drug delivery systems, transdermal patch can maintain stable and effective plasma concentration and therapeutic effect in vivo for a long time after skin dressing delivery, which provides a safe and effective drug-delivery way for the therapy and prevention of some chronic diseases and partial analgesia in a simple and convenient way. Veterinary drug transdermal preparations have been developed both at home and abroad, and satisfactory results have been achieved in the experimental application. Based on the study of veterinary transdermal patches at home and abroad, this paper systematically describes the development and characteristics of transdermal patches, the factors affecting skin permeation and the evaluation this type of preparations in veterinary drugs. 展开更多
关键词 Veterinary drugs Transdermal patches Formulation development New formulation Clinical veterinary
在线阅读 下载PDF
一种基于图像patches分割的自监督生成对抗模型
6
作者 陈才扣 高俊 《软件导刊》 2023年第4期142-147,共6页
近年来,通过将基于角度旋转的自监督模型引入到生成对抗网络中,一定程度上缓解了生成对抗模型稳定性不足与模式坍塌问题。但是,这种自监督模型基于全局信息对比,缺乏局部相关性,模型特征提取能力不足,导致生成图片的全局相似度较高而像... 近年来,通过将基于角度旋转的自监督模型引入到生成对抗网络中,一定程度上缓解了生成对抗模型稳定性不足与模式坍塌问题。但是,这种自监督模型基于全局信息对比,缺乏局部相关性,模型特征提取能力不足,导致生成图片的全局相似度较高而像素精度不足。因此,提出一种新型自监督生成对抗模型,将图像块(patches)引入到传统的角度旋转自监督模型中,通过对图像进行分块,将局部图像与整体图像作为输入,在旋转角度判别器的基础上新增位置判别器,在提高模型全局相似性的同时,增强了局部特征相关性。在CIFAR-10与STL-10数据集上进行测试,实验结果表明,基于图像patches分割的自监督生成模型比角度旋转自监督模型的效果更好。 展开更多
关键词 深度学习 自监督学习 生成对抗模型 patches
在线阅读 下载PDF
Static Force Reliability Analysis of Truss Structure with Piezoelectric Patches Affixed to Its Surface 被引量:3
7
作者 安海 安伟光 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2009年第1期22-31,共10页
For the truss structure composed of active-elements with piezoelectric patches affixed to its surface,taking the mechani-cal-electric coupling effect under the action of electric loads and mechanical loads into consid... For the truss structure composed of active-elements with piezoelectric patches affixed to its surface,taking the mechani-cal-electric coupling effect under the action of electric loads and mechanical loads into consideration,the finite element model for static force analysis is established by using the theory of mechanics. The failure mechanism of piezoelectric elements is discussed and the failure criteria of piezoelectric elements are proposed. The expression of safety margins for the element of piezoelec... 展开更多
关键词 piezoelectric truss structure piezoelectric patch mechanical-electric coupling safety margin stochastic finite element method structural reliability theory
原文传递
A continued study on the bisoprolol and isosorbide dinitrate transdermal patches:cardiovascular protection in spontaneously hypertensive rats 被引量:1
8
作者 魏巍 傅继华 +7 位作者 苏长海 单英 王渊 孔树佳 赵继会 吕万良 王树明 王丽 《Journal of Chinese Pharmaceutical Sciences》 CAS 2008年第3期241-248,共8页
The objective of the present study is to examine cardiovascular protective action of a newly developed transdermal patch by incorporating bisoprolol and isosorbide dinitrate in spontaneously hypertensive rats. As the ... The objective of the present study is to examine cardiovascular protective action of a newly developed transdermal patch by incorporating bisoprolol and isosorbide dinitrate in spontaneously hypertensive rats. As the combination therapy with these two synergistic drugs at low doses through a suitable form of administration could provide optimal therapeutic benefit, we further evaluated the effects of a 42 d period of anti-hypertensive treatment in spontaneously hypertensive rats. Rats were divided into the following five groups: control (blank patch), bisoprolol fumarate tablets (BP-FT, 20.0 mg/kg, i.g.), bisoprolol transdermal patch (BP-TP, 20.0 mg/kg), isosorbide dinitrate transdermal patch (ISDN-TP, 20.0 mg/kg), and the combination of BP and ISDN in a transdermal patch at low doses (8 and 12 mg/kg, respectively). The effects of treatment were evaluated via biochemical indicators related to cardiovascular protection, structure and function. The combination therapy had synergistic anti-hypertensive effects and significantly reduced blood pressure with the benefit of controlling blood pressure variability compared to BP-FT and BP-TP. The combined treatment also reduced heart rate as well as BP-FT and BP-TP, while ISDN-TP had no evident effects on blood pressure, heart rate, and cardiovascular protection. Combination therapy was superior to BP-TP and BP-FT at increasing blood atrial natriuretic peptide and nitric oxide, while also reducing cardiac hydroxyproline and endothelin-1 with no difference in blood endothelin-1 and cardiac malondialdehyde levels. Cardiovascular remodeling differed among the groups, with the combination therapy reducing cardiac hypertrophy and the aortic media/lumen ratio. The consequential improvements in relaxation in response to cumulative concentrations of acetylcholine may explain the associated improvement in endothelial function. Combi- nation treatment with a transdermal patch exhibited a synergistic therapeutic effect. Such favorable cardiovascular effects with nitric oxide donors and β-blockade combination through a transdermal patch may provide long-term cardiovascular protection during anti-hypertensive treatment. 展开更多
关键词 Transdermal patch HYPERTENSION Isosorbide dinitrate BISOPROLOL Cardiovascular protection
暂未订购
Seed movement of bare alkali-saline patches and their potential role in the ecological restoration in Songnen grassland, China 被引量:2
9
作者 WU Ling HE Nian-peng ZHOU Dao-wei 《Journal of Forestry Research》 SCIE CAS CSCD 2005年第4期270-274,共5页
The dynamics of soil seed banks and seed movement was investigated in three bare alkali-saline patches in Songnen grassland, Northeast China, for exploring their potential role in the vegetation restoration of bare al... The dynamics of soil seed banks and seed movement was investigated in three bare alkali-saline patches in Songnen grassland, Northeast China, for exploring their potential role in the vegetation restoration of bare alkali-saline patches. The results showed that the seed banks and the seed movement in these patches were very similar to each other, and to some extent the seed movement was related to patch-side vegetation there. Seed movement across the soil surface of these bare alkali-saline patches was abundant and dominated by the seeds of pioneer species, such as Chloris virgata and Suaeda corniculata, which accounted for over 96% of these trapped seeds. In the contrast, soil seed banks of bare patches were extremely small, in different seasons, especially in May and June, even no any seed have been found, mainly due to lowest retaining capacity of surface soil to those abundant seed movement. Both soil seed banks and seed movement showed seasonal variation, and usually reached the maximum in October. Soil seed banks of bare alkali-saline patches, which were extremely small and difficult to recruit naturally, may inhibit speed of vegetation restoration. It is suggested that seed movement would be the potential seed source and play a potentially important role in the process of vegetation restoration of bare alkali-saline patches by enhancing the soft retaining capacity to seed movement. 展开更多
关键词 Soil seed banks Seed movement Bare alkali-saline patches Restoration ecology
在线阅读 下载PDF
Biomaterials based cardiac patches for the treatment of myocardial infarction 被引量:2
10
作者 Tianqi Chang Chunxia Liu +6 位作者 Kunyan Lu Yong Wu Mingzhu Xu Qian Yu Zhenya Shen Tingbo Jiang Yanxia Zhang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第35期77-89,共13页
Myocardial infarction(MI)is one of the common cardiovascular diseases that occurs with a blockage in one or more of the coronary arteries to lead to the damage of the myocardium,resulting in a lifethreatening conditio... Myocardial infarction(MI)is one of the common cardiovascular diseases that occurs with a blockage in one or more of the coronary arteries to lead to the damage of the myocardium,resulting in a lifethreatening condition.To repair the damaged myocardium in MI,researchers are looking forwards to new ways to postpone the progression of myocardial injury.Cardiac patches,the scaffolds layered on the heart surface,can provide mechanical support for the infarction site and improve cardiac function by delivering various bioactive factors or cells,showing considerable curative effect in the treatment of MI.Biomaterials with certain biocompatibility and mechanical properties have received widespread attention for the application in cardiac patches.In this review,we focus on the recent progress on these biomaterialsbased cardiac patches,which could be categorized into two types according to the sources of materials including(ⅰ)natural materials and(ⅱ)synthetic materials.The major advantages and current challenges of each type are discussed and a brief perspective on the future research directions is presented. 展开更多
关键词 BIOMATERIALS Cardiac patches Myocardial infarction
原文传递
Formulation of unidirectional release buccal patches of carbamazepine and study of permeation through porcine buccal mucosa 被引量:1
11
作者 Parthasarathy Govindasamy Bhaskar Reddy Kesavan Jayaveera Korlakunta Narasimha 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2013年第12期995-1002,共8页
Objective:To achieve transbuccal release of carbamazepine by loading in unidirectional release mucoadhesive buccal patches.Methods:Buccal patches of carbamazepine with unidirectional drug release were prepared using h... Objective:To achieve transbuccal release of carbamazepine by loading in unidirectional release mucoadhesive buccal patches.Methods:Buccal patches of carbamazepine with unidirectional drug release were prepared using hydroxypropyl methyl cellulose,polyvinyl alcohol,polyvinyl pyrrolidone and ethyl cellulose by solvent casting method.Water impermeable backing layer(Pidilite?Biaxially-oriented polypropylene film)of patches provided unidirectional drug release.They were evaluated for thickness,mass uniformity,surface pH and folding endurance.Six formulations FA2,FA8,FA10,FBI,FB14 and FB16(folding endurance above 250)were evaluated further for swelling studies,ex vivo mucoadhesive strength,ex vivo mucoadhesion time,in vitro drug release,ex vivo permeation,accelerated stability studies and FTIR and XRD spectral studies.Results:The ex vivo mucoadhesion time of patches ranged between 109 min(FA10)to 126 min(FB14).The ex vivo mucoadhesive force was in the range of 0.278 lo 0.479 kg/m/s.The in vitro drug release studies revealed that formulation FA8 released 84%and FB16 released 99.01%of drug in140 min.Conclusions:The prepared unidirectional buccal patches of carbamazepine provided a maximum drug release within specified mucoadhesion period and it indicates a potential alternative drug delivery system for systemic denvery of carbamazepine. 展开更多
关键词 BUCCAL patches CARBAMAZEPINE MUCOADHESION Biaxially-oriented polypropylene films PORCINE BUCCAL MUCOSA
暂未订购
Endoscopic identification of Peyer's patches of the terminal ileum in a patient with Crohn's disease 被引量:1
12
作者 Hiroshi Ishimoto Hajime Isomoto +6 位作者 Saburo Shikuwa Chun Yang Wen Takashi Suematu Masahiro Ito Ikuo Murata Hiromi Ishibashi Shigeru Kohno 《World Journal of Gastroenterology》 SCIE CAS CSCD 2004年第18期2767-2768,共2页
We presented a 20-year-old patient with Crohn's disease (CD).Colonoscopy revealed longitudinal ulceration in the terminal ileum and rectal aphtoid ulcers.After treatment with mesalamine and total parenteral nutrit... We presented a 20-year-old patient with Crohn's disease (CD).Colonoscopy revealed longitudinal ulceration in the terminal ileum and rectal aphtoid ulcers.After treatment with mesalamine and total parenteral nutrition,repeat colonoscopy revealed a granular elevated area in the terminal ileum,which appeared as an irregular dome-like elevation with irregularly arranged villi on magnifying endoscopy.Biopsy specimens taken from the region showed microgranulomas and lymphoid hyperplasia,Scanning electron microscopy revealed the presence of M cells,confirming that the area corresponded to Peyer's patches.Peyer's patches by magnifying endoscopy and electron microscopy may provide insights into the pathogenesis of CD. 展开更多
关键词 Adult BIOPSY Crohn Disease Endoscopes Gastrointestinal Humans ILEUM Intestinal Mucosa Male Microscopy Electron Scanning Peyer's patches
暂未订购
Infiltration pattern beneath shrub canopy and interspace grass patches in typical steppe ecosystems of Inner Mongolia, China 被引量:2
13
作者 ZHANG Si-yi LI Xiao-yan +1 位作者 PENG Hai-ying ZHANG Zhi-hua 《地球环境学报》 2012年第6期1117-1125,共9页
Water is the most critical factor for controlling die vegetation pattern in arid and semiarid regions.Using a dye-tracing experiment,we analyzed the infiltration pattern beneath shrub canopy and interspace grass patch... Water is the most critical factor for controlling die vegetation pattern in arid and semiarid regions.Using a dye-tracing experiment,we analyzed the infiltration pattern beneath shrub canopy and interspace grass patches in typical steppe ecosystems.The dye coverage,uniform infiltration depth,maximum infiltration depth,total stained area and heterogeneous infiltration stained area were measured by two indices,the maximum infiltration depth index(MIDI)and heterogeneous infiltration index(HII),which were calculated by processing dye-stained photos.The MIDI and HII of soil under shrubs were 1.41±0.14 and 0.29±0.068,respectively,and larger than those of grass soil,1.26±0.14 and0.20±0.076.Using the MIDI,HII,field soil moisture and rainfall data,the infiltration depth and heterogeneous infiltration amount for 26 nature rainfall events were calculated.The results imply that water can infiltrate to a deeper layer beneath shrub canopy than beneath grass patches and that more water infiltration occurs beneath shrub canopy than beneath grass patches.These results are of prime importance for arid and semiarid ecosystems with a limited water supply due to high evaporation and low precipitation. 展开更多
关键词 Infiltration pattern dye-tracing SHRUB grass patches typical steppe ecosystems
在线阅读 下载PDF
The Dual-Polarized Staggered Stacked Patches Antenna 被引量:1
14
作者 Xinyu Cao Jinling Zhang +1 位作者 Hongzhen Yang Hourong Li 《China Communications》 SCIE CSCD 2021年第12期208-218,共11页
A new dual-polarized staggered and stacked patches antenna with wide impedance band-width and high isolation is proposed.The antenna consists of two groups of radiation patches,in 7 layers,and uses the orthogonal adja... A new dual-polarized staggered and stacked patches antenna with wide impedance band-width and high isolation is proposed.The antenna consists of two groups of radiation patches,in 7 layers,and uses the orthogonal adjacent coupling structure on staggered layer to excite a pair of linear polarization modes.Thanks to the staggered feeder mode,it has increased the isolation performance be-tween ports and compressed the transverse size of the antenna.As a result of the combination of staggered stack-up between the patches and the stepped gradient shape of the main radiating patches,it has effectively expanded the impedance bandwidth of the antenna.The proposed antenna is simulated,fabricated and measured.The staggered feeding structure effectively reduces the cross-sectional area of the antenna,and greatly improves the isolation between feeding ports.The measurement results show that the impedance bandwidths for vertical and horizontal polarization modes are 40.2%(638-960 MHz)and 40.0%(645-968 MHz)respectively when the return loss is lower than-10 dB,and the isolation between feeding ports is better than-30 dB.Meanwhile,the antenna has a stable and symmetrical radiation pattern across the working band,therefore making it suitable to be used as antenna and antenna array element of mobile wireless communication base stations. 展开更多
关键词 staggered stacked patches wide impedance bandwidth high isolation
在线阅读 下载PDF
Aboveground Woody Biomass, Carbon Stocks Potential in Selected Tropical Forest Patches of Tripura, Northeast India 被引量:1
15
作者 Koushik Majumdar Bal Krishan Choudhary Badal Kumar Datta 《Open Journal of Ecology》 2016年第10期598-612,共15页
To estimate woody plant biomass stocks in different patches of forest ecosystems, total 20, 500 × 10 m (0.5 ha) sized line transects were laid in a protected area of Tripura, Northeast India. Overall, 9160 indivi... To estimate woody plant biomass stocks in different patches of forest ecosystems, total 20, 500 × 10 m (0.5 ha) sized line transects were laid in a protected area of Tripura, Northeast India. Overall, 9160 individuals were measured at ≥10 cm diameter at breast height (dbh) in 10 ha sampled area. Estimation of biomass suggested that highest coefficient for allometric relationships between density and biomass in 10 dbh classes was observed in bamboo brakes (R<sup>2</sup> = 0.90) than lowest for semi evergreen patch (R<sup>2</sup> = 0.48). The stock of carbon (C) was differ significantly along the forest patches (F = 7.01, df = 3.19;p < 0.01). Most of biomass stock (69.38%) was accumulated in lower dbh class (<30 cm) and only 23% of biomass was estimated at higher dbh classes (> 70 cm). Range of biomass stock (37.85 - 85.58 Mg ha<sup>-</sup><sup>1</sup>) was low, compared to other tropical forest ecosystems in India, which implies that the proper management is required to monitor regional ecosystem C pool. 展开更多
关键词 Woody Biomass Potential Carbon Storage Tropical Forest patches Tripura
在线阅读 下载PDF
STUDY ON CRACKED PLATES WITH BONDED PATCHES UNDER IN PLANE BIAXIAL LOADINGS
16
作者 徐建新 魏志毅 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1999年第2期141-147,共7页
Based on the finite element method, a numerical investigation into the bonded repair efficiency of cracked plates under in plane biaxial loadings is presented. The main considerations are: reduction in stress intensi... Based on the finite element method, a numerical investigation into the bonded repair efficiency of cracked plates under in plane biaxial loadings is presented. The main considerations are: reduction in stress intensity factor (SIF) at the crack tip, the maximum tensile stress in the composite patch and the maximum shear stress in the adhesive bond between the patch and the plate. Without the patch, a tensile or compressive stress parallel to the crack has no effect on the SIF at the crack tip. While with a composite patch, there exists coupling effect between the normal stress parallel to the crack and the SIF, and the coupling effect depends significantly on ply orientation of the patch and the biaxial stress ratio of the plate. 展开更多
关键词 composite patch CRACK stress intensity factor stress ratio
在线阅读 下载PDF
Influences of pika and simulated grazing disturbances on bare patches of alpine meadow in the Yellow River Source Zone
17
作者 LI Jie-xia LI Xi-lai +3 位作者 GAO Jay SHI Yan MA Ge-liang Ka-zhao-cai-rang 《Journal of Mountain Science》 SCIE CSCD 2021年第5期1307-1320,共14页
Bare patches in alpine meadow are the main manifestation of its degradation.The change of bare patches in an alpine meadow in the Yellow River Source Zone during 2018-2019 was studied in relation to the disturbances c... Bare patches in alpine meadow are the main manifestation of its degradation.The change of bare patches in an alpine meadow in the Yellow River Source Zone during 2018-2019 was studied in relation to the disturbances caused by plateau pika(Ochotona curzoniae)population and simulated grazing via artificial mowing both independently and interactively.The disturbance was set at three levels of high,medium and no disturbance(control group).Bare patches were mapped by from unmanned aerial vehicle(UAV)images with fine resolution of 1 cm obtained in August 2018 and August 2019 in ArcGIS.The results showed that the total area of bare patches decreased by 112.05 m2 in sub-plots devoid of pika disturbance but increased by 126.37 m2 in other subplots.The highest rate of increase is 89.02%.The individual effect of pika exceeds the joint effect of pika and mowing disturbances.The sole effect of mowing is lower than the joint effect of pika disturbance and intensive mowing,but higher than the joint influence of pika disturbance and moderate mowing.Strong pika disturbance(14 per sub-plot)caused the influence of mowing from moderate to intensive to increase by five-fold.The area of bare patches treated with moderate mowing and no pika disturbance decreased at the highest pace(-37.22%).Intensive mowing and medium density pikas(100 pikas/ha)are considered the thresholds at which the bare patches start to expand.Even if the meadow is mowed at the medium and high intensity,the area of bare patches can be significantly reduced if plateau pika population is controlled to a low level.ANOVA analysis and longterm macro-scale satellite-derived results reveal that pika disturbance is more important in causing the bare patches to change than simulated grazing.Therefore,it is more important to control the number of pikas than to reduce grazing intensity to prevent the expansion of bare patches in the degraded alpine meadow in the study area. 展开更多
关键词 Bare patches simulated grazing Pika disturbance Interactive influence UAV Yellow River Source Zone
原文传递
Divergent responses of Picea crassifolia Kom.in different forest patches to climate change in the northeastern Tibetan Plateau
18
作者 Zhongtong Peng Qifeng Mo +5 位作者 Liangjun Zhu Qingao Lu Jiaqing Cai Mingming Guo Kun Xu Yuandong Zhang 《Forest Ecosystems》 SCIE CSCD 2023年第6期752-762,共11页
Global climate changes have significantly affected tree growth and forest structures and functions in some arid and semi-arid regions,which are becoming warmer and wetter.Due to natural factors such as climate and ter... Global climate changes have significantly affected tree growth and forest structures and functions in some arid and semi-arid regions,which are becoming warmer and wetter.Due to natural factors such as climate and terrain,some tree species may form different forest patches at the edges of their distribution areas.However,how forest patches of various sizes respond to climate change is unclear.In this study,we collected 203 tree cores from six different sizes of forest patches at the edge of the distribution area of Picea crassifolia Kom.in the northeast Tibetan Plateau.And we used the dendrochronology method to study the response of tree growth and resilience in different forest patches to climate change from 1961 to 2020.We simultaneously measured the contents of nonstructural carbohydrates(NSC),total nitrogen and total phosphorus of tree needles.Our results showed that the growth of trees in small-and medium-size forest patches(0.8–18.6 ha)has increased significantly.The early growing season(May–July)minimum temperature was the most important climate factor driving the growth of small-and medium-sized patch trees.The early growing season maximum temperature was the most important climate factor that inhibited the growth of trees in the largest patches(362.8 ha).The growth of individual trees in medium forest patches was better and the correlation with annual minimum temperature,maximum temperature,precipitation,actual evapotranspiration,and palmer drought severity index was stronger.The higher NSC content,stronger photosynthesis,and higher nitrogen utilization efficiency in leaves might be one of the reasons for the better growth of trees in moderate forest patches.In extreme drought years,as the forest patch area increased,the overall trend of tree growth resistance showed a unimodal pattern,with the highest at a forest patch area of 7.1 ha,while the overall trend of tree growth recovery was opposite.Therefore,we should strengthen the management of trees in large forest patches to cope with climate change. 展开更多
关键词 Climate change Picea crassifolia Kom Forest patches Tree growth RESILIENCE
在线阅读 下载PDF
Deep Global Multiple-Scale and Local Patches Attention Dual-Branch Network for Pose-Invariant Facial Expression Recognition
19
作者 Chaoji Liu Xingqiao Liu +1 位作者 Chong Chen Kang Zhou 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第4期405-440,共36页
Pose-invariant facial expression recognition(FER)is an active but challenging research topic in computer vision.Especially with the involvement of diverse observation angles,FER makes the training parameter models inc... Pose-invariant facial expression recognition(FER)is an active but challenging research topic in computer vision.Especially with the involvement of diverse observation angles,FER makes the training parameter models inconsistent from one view to another.This study develops a deep global multiple-scale and local patches attention(GMS-LPA)dual-branch network for pose-invariant FER to weaken the influence of pose variation and selfocclusion on recognition accuracy.In this research,the designed GMS-LPA network contains four main parts,i.e.,the feature extraction module,the global multiple-scale(GMS)module,the local patches attention(LPA)module,and the model-level fusion model.The feature extraction module is designed to extract and normalize texture information to the same size.The GMS model can extract deep global features with different receptive fields,releasing the sensitivity of deeper convolution layers to pose-variant and self-occlusion.The LPA module is built to force the network to focus on local salient features,which can lower the effect of pose variation and self-occlusion on recognition results.Subsequently,the extracted features are fused with a model-level strategy to improve recognition accuracy.Extensive experimentswere conducted on four public databases,and the recognition results demonstrated the feasibility and validity of the proposed methods. 展开更多
关键词 Pose-invariant FER global multiple-scale(GMS) local patches attention(LPA) model-level fusion
在线阅读 下载PDF
The Influence of HIF-1α Expression on Apoptosis and Number of T Lymphocyte in Peyer’s Patches after Burn with Delayed Fluid Resuscitation in Rats at Plateau
20
作者 Cheng Zhang Yi Liu +1 位作者 Ming Ma Shifan Zhang 《Surgical Science》 2016年第9期390-399,共10页
Objective: To research the expression of hypoxia inducible factor-1 alpha (HIF-1 alpha) on the apoptosis and number of T lymphocyte in Peyer’s patches after severe burn on plateau in rats. Methods: Wistar rats (n = 1... Objective: To research the expression of hypoxia inducible factor-1 alpha (HIF-1 alpha) on the apoptosis and number of T lymphocyte in Peyer’s patches after severe burn on plateau in rats. Methods: Wistar rats (n = 130) were subjected to deep thickness burn injury (30% TBSA, III degree), at two different altitudes. 60 of them were given delayed fluid resuscitation (DFR, n = 30 at each altitude) 6 h after burn at different altitude;60 of them were carried out immediate fluid resuscitation (IFR, n = 30 at each altitude);10 rats were subjected to 37°C warm water as sham burn (SG, n = 10). The Peyer’s patches were harvested from the ileum of rats at different time point after burn respectively. The expression of HIF-1 alpha, CD3(+) and the apoptosis and number of T lymphocyte in Peyer’s patches were detected by tissue microarray technology and immunohistochemistry. Results: The apoptosis was higher in DFR group than that in IFR group. The increase in HIF-1 alpha expression was observed mainly on cell nucleus in T lymphocytes. The expression levels of HIF-1 alpha in Peyer’s patches were much higher in DFR group and IFR group than those in SG, and they were higher at high altitude (3848 metres) than those at lower altitude (1517 metres), and also higher in DFR group compared with IFR group (all P < 0.05). The expression levels of CD3<sup>+</sup> in Peyer’s patches were much lower in DFR group and IFR group than those in sham group, and the lowest value appeared at 12 hours after burn (all P < 0.05). Conclusion: High expression of HIF-1 alpha may induce the apoptosis of T lymphocytes in Peyer’s patches after severe burn with delayed fluid resuscitation in rats at plateau. 展开更多
关键词 Delayed Fluid Resuscitation Peyer’s patches APOPTOSIS HIF-1Α BURN PLATEAU
暂未订购
上一页 1 2 43 下一页 到第
使用帮助 返回顶部