期刊文献+
共找到2,882篇文章
< 1 2 145 >
每页显示 20 50 100
A new generalized fractional Dirac soliton hierarchy and its fractional Hamiltonian structure 被引量:1
1
作者 魏含玉 夏铁成 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第11期26-31,共6页
Based on the differential forms and exterior derivatives of fractional orders, Wu first presented the generalized Tu formula to construct the generalized Hamiltonian structure of the fractional soliton equation. We ap... Based on the differential forms and exterior derivatives of fractional orders, Wu first presented the generalized Tu formula to construct the generalized Hamiltonian structure of the fractional soliton equation. We apply the generalized Tu formula to calculate the fractional Dirac soliton equation hierarchy and its Hamiltonian structure. The method can be generalized to the other fractional soliton hierarchy. 展开更多
关键词 fractional calculus generalized Tu formula Dirac soliton hierarchy Hamiltonian struc- ture
下载PDF
瑞敏系列和TURE TEST系列斑贴试剂检测结果比较 被引量:5
2
作者 曹晓佳 张理涛 《中国皮肤性病学杂志》 CAS 北大核心 2012年第1期19-21,共3页
目的分析瑞敏系列(R)和TURE TEST系列(T)斑贴试剂检测结果及一致性。方法分别用这两个系列斑贴试剂检测196例慢性湿疹和接触性皮炎患者,对其检测结果进行比较。结果瑞敏系列和TURE TEST系列斑贴试剂对各变应原检测阳性率不完全相同,它... 目的分析瑞敏系列(R)和TURE TEST系列(T)斑贴试剂检测结果及一致性。方法分别用这两个系列斑贴试剂检测196例慢性湿疹和接触性皮炎患者,对其检测结果进行比较。结果瑞敏系列和TURE TEST系列斑贴试剂对各变应原检测阳性率不完全相同,它们检测常见变应原种类均与国内已有报道类似;两个系列中相同的16种变应原的检测反应强度一致性较好,检测的阳性率差异无统计学意义(P>0.05)。结论两个系列斑贴试剂的一致性较好,临床上可根据患者情况选择应用。 展开更多
关键词 斑贴试验 瑞敏 ture TEST
下载PDF
The Model of Poverty Alleviation and Income Growth by Developing Plateau-characterized Agriculture and Its Achievements Analysis in Yunnan Province——a Case Study in Midu County, Dali Bai Autonomous Prefecture 被引量:3
3
作者 杨人懿 詹文惠 +4 位作者 钱倩 朱朝琼 李玉珠 黄啸宇 杨子生 《Agricultural Science & Technology》 CAS 2017年第4期744-746,752,共4页
The policy of taking the targeted poverty alleviation measures has been the mission of the age in propelling the 13th Five-year Plan and building moderately prosperous society. A good poverty alleviation model is of s... The policy of taking the targeted poverty alleviation measures has been the mission of the age in propelling the 13th Five-year Plan and building moderately prosperous society. A good poverty alleviation model is of significance for the goal. The research introduced a poverty-stricken county-Midu County, Dali Bai Au- tonomous Prefecture, analyzed the basic approaches and the main achievements of "the model of poverty alleviation and income growth by developing plateau-charac- terized agriculture", and proposed some suggestions to promoting and applying this model. The research provides references for plateau-characterized agricultural devel- opment and targeted poverty alleviation strategy. 展开更多
关键词 Targeted poverty alleviation Plateaus in Yunnan Characteristic agricul- ture Poverty alleviation model ACHIEVEMENTS Midu County
下载PDF
Plant diversity, population structure, and regeneration status in disturbed tropical forests in Assam, northeast India 被引量:4
4
作者 Gitamani Dutta Ashalata Devi 《Journal of Forestry Research》 SCIE CAS CSCD 2013年第4期715-720,共6页
We investigated the plant population structure and the phy- tosociological and regeneration status in two disturbed tropical forests in Assam Province, the Hojai Reserve Forest and Kumorakata Reserve Forest. A total o... We investigated the plant population structure and the phy- tosociological and regeneration status in two disturbed tropical forests in Assam Province, the Hojai Reserve Forest and Kumorakata Reserve Forest. A total of 166 species (80 trees, 20 shrubs and 66 herbs) of 136 genera and 63 families were recorded in both study sites. The disturbance index at the two sites, Kumorakata Reserve Forest and Hojai Reserve Forest, were recorded at 11.4% and 3.70% respectively. Reverse J-shaped population curve and exploitation of tree species in higher girth classes were recorded at both study sites. In the girth classes (10-30 cm, 30-60 cm, 60-90 cm and 90-120 cm in size) the percentage of cut stump density was higher than the percentage of individual living trees. The 18% (Kumorakata Reserve Forest) and 7% (Hojai Reserve Forest) spe- cies were recorded as not regenerating. Illegal felling and over-exploitation of forest resources may lead to species-specific changes in the population structure and can alter the future structure and composi- tion of the forests. 展开更多
关键词 plant diversity REGENERATION DISTURBANCE population struc-ture ASSAM INDIA
下载PDF
Developmental Threshold Temperature and Effective Accumulative Tem- perature of Pupae and Eggs of Holcocerus hippophaecolus 被引量:8
5
作者 ZongShixiang LuoYouqing WangTao XuZhichun LuChangkuan 《Forestry Studies in China》 CAS 2004年第4期34-38,共5页
In order to understand the occurrence and the developmental regularity of seabuckthorn carpenterworm (Holcocerus hippophaecolus) and predict its population density, the developmental threshold temperature (C) and effe... In order to understand the occurrence and the developmental regularity of seabuckthorn carpenterworm (Holcocerus hippophaecolus) and predict its population density, the developmental threshold temperature (C) and effective accumulative tem- perature (K) of the carpenterworm pupae and eggs were analyzed under the conditions of constant and variable temperatures. The results show that the values of C and K of the carpenterworm pupae are (12.1 ± 0.2) °C and (295.2 ± 4.1) day-degrees at constant temperatures, and (15.5 ± 0.4) °C and (202.4 ± 13.1) day-degrees at variable temperatures. However, the values of C and K of the eggs at variable temperatures are (16.7 ± 0.8) °C and (101.5 ± 12.6) day-degrees. The differences of developmental threshold and effective accumulative temperature under the conditions of constant and variable temperatures of the carpenterworm pupae accord with the developmental regularity of most insects in nature. By comparing five different constant temperatures, the conclusion is that the optimum developmental temperature of the pupae is 21 °C when both the pupation of the mature larvae and the eclosion of the pupae are very accordant. Moreover, the percentage of eclosion is over 90%. The average developmental durations of the carpenter- worm pupae and eggs are 31 and 16 d at variable temperatures. 展开更多
关键词 Holcocerus hippophaecolus PUPAE EGGS developmental threshold temperature effective accumulative tempera- ture
下载PDF
Local Geometric Proof of Riemann Conjecture 被引量:3
6
作者 Chuanmiao Chen 《Advances in Pure Mathematics》 2020年第10期589-610,共22页
Riemann hypothesis (RH) is a difficult problem. So far one doesn’t know how to go about it. Studying <i>ζ</i> and using analysis method likely are two incor-rect guides. Actually, a unique hope may study... Riemann hypothesis (RH) is a difficult problem. So far one doesn’t know how to go about it. Studying <i>ζ</i> and using analysis method likely are two incor-rect guides. Actually, a unique hope may study Riemann function <img alt="" src="Edit_8fcdfff5-6b95-42a4-8f47-2cabe2723dfc.bmp" />, <img alt="" src="Edit_6ce3a4bd-4c68-49e5-aabe-dec3e904e282.bmp" />, <img alt="" src="Edit_29ea252e-a81e-4b21-a41c-09209c780bb2.bmp" /> by geometric analysis, which has the symmetry: v=0 if <i>β</i>=0, and basic expression <img alt="" src="Edit_bc7a883f-312d-44fd-bcdd-00f25c92f80a.bmp" />. We show that |u| is single peak in each root-interval <img alt="" src="Edit_d7ca54c7-4866-4419-a4bd-cbb808b365af.bmp" /> of <i>u</i> for fixed <em>β</em> ∈(0,1/2]. Using the slope u<sub>t</sub>, we prove that <i>v</i> has opposite signs at two end-points of I<sub>j</sub>. There surely exists an inner point such that , so {|u|,|v|/<em>β</em>} form a local peak-valley structure, and have positive lower bound <img alt="" src="Edit_bac1a5f6-673e-49b6-892c-5adff0141376.bmp" /> in I<sub>j</sub>. Because each <i>t</i> must lie in some I<sub>j</sub>, then ||<em>ξ</em>|| > 0 is valid for any <i>t</i> (<i>i.e.</i> RH is true). Using the positivity <img alt="" src="Edit_83c3d2cf-aa7e-4aba-89f5-0eb44659918a.bmp" /> of Lagarias (1999), we show the strict monotone <img alt="" src="Edit_87eb4e9e-bc7b-43e3-b316-5dcf0efaf0d5.bmp" /> for <i>β</i> > <i>β</i><sub>0</sub> ≥ 0 , and the peak-valley structure is equiva-lent to RH, which may be the geometric model expected by Bombieri (2000). This research follows Liuhui’s methodology: “Computing can detect the un-known and method”.</i> 展开更多
关键词 Riemann Conjecture Local Geometric Proof Symmetry Peak-Valley struc-ture EQUIVALENCE Liuhui’s Methodology
下载PDF
Effects of Rare Earth and Hot Pressing Sintering Temperature on the Transverse Rupture Strength of Fe-based Diamond Composites 被引量:5
7
作者 DAI Qiu-lian, LUO Can-ben, XU Xi-peng, WANG Yong-chu (College of Mechanical Engineering & Automation, Huaqiao University, Quanzhou 362011, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期76-77,共2页
Effects of sintering temperature in hot pressing, t yp es, states and amounts of rare earth as well as TiH 2 on the transverse rupture strength (TRS) of Fe-based composites are studied by means of orthogonal test and ... Effects of sintering temperature in hot pressing, t yp es, states and amounts of rare earth as well as TiH 2 on the transverse rupture strength (TRS) of Fe-based composites are studied by means of orthogonal test and variance analysis in this paper. It is found that sintering temperature has a significant effect on the TRS of Fe-based diamond composites. The optimal sin tering temperature is 780~860 ℃. On the contrary, the effects of RE additi v es on values of TRS of the diamond composites have on distinct difference no mat ter the RE is in the state of mixture or compound or oxidization. Experimental r esults demonstrate that Fe-based diamond composites with RE additives exhibit h igher TRS, which results in an increase in diamond retention capacity. The degre e of increment of TRS is different at different sintering temperatures. The opti mal amount of rare earth was found to be about 1% in weight. The effect of RE is more significant at lower sintering temperature. The experimental results also reveal that TiH 2 additive has a negative effect on the TRS of Fe-based compos ites. Microscope observations demonstrate that specimen without TiH 2 additives , shows fewer pores and denser structures in the base metal. It can also be seen from the SEM observation of the resulting fracturing surface of bending test sp ecimens that the bonding of the diamond-matrix interface is better in the speci men without TiH 2 than in the specimen with TiH 2. Also the fracture surface o f the specimen without TiH 2 reveals ductile cup and cone behavior. 展开更多
关键词 rare earth sintering temperature transverse rup ture strength diamond impregnated composite
下载PDF
Analysing the structure of the optical path length of a supersonic mixing layer by using wavelet methods 被引量:1
8
作者 高穹 易仕和 +2 位作者 姜宗福 赵玉新 谢文科 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第6期344-351,共8页
The nano-particle-based planar laser scattering (NPLS) technique is used to measure the density distribution in the supersonic mixing layer of the convective Mach number 0.12, and the optical path difference (OPL)... The nano-particle-based planar laser scattering (NPLS) technique is used to measure the density distribution in the supersonic mixing layer of the convective Mach number 0.12, and the optical path difference (OPL), which is quite crucial for the study of aero-optics, is obtained by post processing. Based on the high spatiotemporal resolutions of the NPLS, the structure of the OPL is ana]ysed using wavelet methods. The coherent structures of the OPL are extracted using three methods, including the methods of thresholding the coefficients of the orthogonal wavelet transform and the wavelet packet transform, and preserving a number of wavelet packet coefficients with the largest amplitudes determined by the entropy dimension. Their performances are compared, and the method using the wavelet packet is the best. Based on the viewpoint of multifractals, we study the OPL by the wavelet transform maxima method (WTMM), and the result indicates that its scaling behaviour is evident. 展开更多
关键词 optical path difference AERO-OPTICS supersonic mixing layer WAVELET coherent struc-tures scaling behavior
下载PDF
Responses of Grassland and Forest to Temperature and Precipitation Changes in Northeast China 被引量:3
9
作者 彭静 董文杰 +1 位作者 袁文平 张勇 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2012年第5期1063-1077,共15页
Using the Normalized Difference Vegetation Index (NDVI) as an indicator of vegetation growth, we explored the characteristics and differences in the response to drought of five vegetation biomes in Northeast China, ... Using the Normalized Difference Vegetation Index (NDVI) as an indicator of vegetation growth, we explored the characteristics and differences in the response to drought of five vegetation biomes in Northeast China, including typical steppe, desert steppe, meadow steppe, deciduous coniferous forest and deciduous broad-leaved forest during the period 1982 2009. The results indicate that growing season precipitation may be the primary vegetation growth-limiting factor in grasslands. More than 70% of the temporal variations in NDVI can be explained by the amount of precipitation during the growing season in typical and desert steppes. During the same period, the mean temperature in the growing season could explain nearly 43% of the variations in the mean growing season NDVI and is therefore a dominant growth-limiting factor for forest ecosystems. Therefore, the NDVI trends differ largely due to differences in the vegetation growth-limiting factors of the different vegetation biomes. The NDVI responses to droughts vary in magnitude and direction and depend on the drought-affected areas of the five vegetation types. Specifically, the changes in NDVI are consistent with the variations in precipitation for grassland ecosystems. A lack of precipitation resulted in decreases in NDVI, thereby reducing vegetation growth in these regions. Conversely, increasing precipitation decreased the NDVI of forest ecosystems. The results also suggest that grasslands under arid and semi-arid environments may be more sensitive to drought than forests under humid environments. Among grassland ecosystems, desert steppe was most sensitive to drought, followed by typical steppe; meadow steppe was the least sensitive. 展开更多
关键词 DROUGHT GRASSLAND FOREST NDVI departures precipitation departures temperature depar- tures Northeast China
下载PDF
Design, Synthesis, Crystal Structure and Photophysical Properties of New Oxadiazole Extended Viologen Fluorophore 被引量:1
10
作者 Tetsuji Moriguchi Masataka Okuyama Venkataprasad Jalli 《Crystal Structure Theory and Applications》 2021年第2期27-37,共11页
Viologens (<i>N,N'</i>-dimethyl-4,4-bipyridinium) are advanced functional materials, found important applications in electrochromic devices, molecular machines, organic batteries, and carbohydrate oxid... Viologens (<i>N,N'</i>-dimethyl-4,4-bipyridinium) are advanced functional materials, found important applications in electrochromic devices, molecular machines, organic batteries, and carbohydrate oxidation catalysts in alkaline fuel. In this article, we investigated the design, synthesis and photophysical properties of <i>N,N'</i>-dimethyl-2,5-Bis(pyridinium)oxadiazole <b>4</b> and its precursor 2,5- Bis(pyridine)oxadiazole<b> 2</b>. The crystal structure and photophysical properties of viologen <b>4</b> and precursor <b>2</b> have been determined. The viologen molecule <b>4</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n</i> with four molecules in unit cell. Precursor molecule <b>2</b> also crystalized in monoclinic form, space group <i>C</i>2/<i>c</i> with four molecules in unit cell. From X-rd data, we found three cations in the molecular structure of viologen molecule <b>4</b>, which is unusual in viologens. In the three-dimensional molecular packing diagram of molecule <b>4</b>, the three cations and iodate anions are stabilized by C···C, C···I, N···I, N···H, H···I, N—H···I and C—H···I. The dihedral angle between planes having oxadiazole and two benzene rings are 5&#176;and 8&#176;, suggesting the molecule <b>4</b> is a slightly strained one. The molecular structure of precursor molecule <b>2</b> stabilized by C···C and N···H short contacts between the molecules. The molecule <b>4</b> displayed strong absorbance at 315 nm and emissions between 390 - 410 nm. 展开更多
关键词 Oxadiazole Extended Methyl Viologen Bipyridine Oxadiazole Crystal struc-ture Pyridine-4-Carboxy Aldehyde Isonicotinic Acid Hydrazide Fluorescence
下载PDF
Intelligent Intercommunicating Multiscale Engineering: The Engineering of the Future 被引量:1
11
作者 Yue Yuan Jesse Zhu 《Engineering》 SCIE EI CAS CSCD 2023年第11期13-19,共7页
1.Introduction Despite being widely known and investigated as a computer science discipline,artificial intelligence(AI)has attracted incomparable interest from researchers in diversified areas[1].In 1950,Alan Turing r... 1.Introduction Despite being widely known and investigated as a computer science discipline,artificial intelligence(AI)has attracted incomparable interest from researchers in diversified areas[1].In 1950,Alan Turing raised the classic question that has inspired numerous researchers to date:“Can machines think?”[2].The ultimate benchmark of AI was set by Turing’s revised“imitation game.” 展开更多
关键词 COMPUTER artificial TURING
下载PDF
基于相对联系数的区域水利高质量发展评价指标体系筛选方法 被引量:4
12
作者 金菊良 周亮广 +4 位作者 王平 崔毅 吴成国 周戎星 袁康 《华北水利水电大学学报(自然科学版)》 北大核心 2024年第1期43-51,共9页
为综合判断在区域水利高质量发展目标、发展途径、发展条件相互作用下区域水资源-经济社会-生态环境复合系统不断协同优化的系统高质量发展水平状态,构建了由发展目标、发展途径和发展条件3个子系统组成的区域水利高质量发展初步评价指... 为综合判断在区域水利高质量发展目标、发展途径、发展条件相互作用下区域水资源-经济社会-生态环境复合系统不断协同优化的系统高质量发展水平状态,构建了由发展目标、发展途径和发展条件3个子系统组成的区域水利高质量发展初步评价指标体系。为定量分析初步评价指标体系的专家咨询信息,根据专家指标排序合理性模糊关系的取值区间特点提出了相对联系数,用相对联系数的平均集对势估计各专家指标排序合理性的权重,进而可得各指标重要性的专家综合排序值,据此筛选初步评价指标体系,构建了基于相对联系数的区域水利高质量发展评价指标体系筛选方法(SM-RCN)。SM-RCN在陕西省的应用结果表明:筛选后的指标体系汇聚了各专家对区域水利高质量发展主要影响指标的综合评判;SM-RCN可克服评价指标体系构建过程缺乏定量分析依据的不足,可识别不同专家、同一专家对不同评价方面的指标排序合理性的程度。该筛选方法在区域水利现代化、水资源空间均衡、水资源承载力等评价指标体系构建过程中具有应用前景。 展开更多
关键词 水利高质量发展 评价指标体系 指标筛选 系统结构 集对分析 相对联系数 平均集对势 陕西省
下载PDF
Healing time of incision infection after hepatobiliary surgery treated by needle-free incision suture closure 被引量:8
13
作者 Wen-Jie Ma Yong Zhou +10 位作者 Hui Mao Rui-Hua Xu Anuj Shrestha Fu-Yu Li Alex Lorance Qin Yang Yong-Qiong Zhang Ting Jiang Huan Feng Wei Zhang Nan-Sheng Cheng 《World Journal of Gastroenterology》 SCIE CAS 2014年第42期15815-15819,共5页
AIM: To compare the effectiveness of needle-free incision suture closure with butterfly tape and traditional secondary suturing techniques in treating incision infection. METHODS: Two hundred and twenty-three patients... AIM: To compare the effectiveness of needle-free incision suture closure with butterfly tape and traditional secondary suturing techniques in treating incision infection. METHODS: Two hundred and twenty-three patients with incision infection following hepatobiliary surgery at a tertiary hospital were randomly divided into three groups: 90 patients were closed by needle-free incision suture closure, which gradually closed the incision wound when drainage from incision infection was visibly decreased and healthy granulation tissues had grown; 79 patients were closed by butterfly bandage; another 54 patients were closed by traditional secondary suturing technique. Healing time of incision infection was calculated from the beginning of dressing change to the healing of the incision. RESULTS: Healing time in the needle-free incision suture closure group (24.2 +/- 7.2 d) was significantly shorter than that in the butterfly bandage group (33.3 +/- 11.2 d) and the traditional secondary suturing group (36.2 +/- 15.3 d) (P < 0.05). Healing time in the butterfly bandage group appeared to be slightly shorter than that in the secondary suture group, but the difference was not statistically significant (P > 0.05). CONCLUSION: Needle-free incision suture closure could gradually close the infection wound at the same time of drainage and dressing change, thereby shortening the healing time. (C) 2014 Baishideng Publishing Group Inc. All rights reserved. 展开更多
关键词 Incision infection Needle-free incision suture closure Secondary suture Drainage Wound healing Hepatobiliary surgery
下载PDF
Interesting rendezvous location in a liver transplantation patient with anastomosis stricture 被引量:5
14
作者 Bulent Odemis Erkin Oztas +3 位作者 Mehmet Yurdakul Serkan Torun Nuredtin Suna Ertugrul Kayacetin 《World Journal of Gastroenterology》 SCIE CAS 2014年第42期15916-15919,共4页
An endoscopic or radiologic percutaneous approach may be an initial minimally invasive method for treating biliary strictures after living donor liver transplantation; however, cannulation of biliary strictures is som... An endoscopic or radiologic percutaneous approach may be an initial minimally invasive method for treating biliary strictures after living donor liver transplantation; however, cannulation of biliary strictures is sometimes difficult due to the presence of a sharp or twisted angle within the stricture or a complete stricture. When an angulated or twisted biliary stricture interrupts passage of a guidewire over the stricture, it is difficult to replace the percutaneous biliary drainage catheter with inside stents by endoscopic retrograde cholangiopancreatography. The rendezvous technique can be used to overcome this difficulty. In addition to the classical rendezvous method, in cases with complete transection of the common bile duct a modified technique involving the insertion of a snare into the subhepatic space has been successfully performed. Herein, we report a modified rendezvous technique in the duodenal bulb as an extraordinary location for a patient with duct-to-duct anastomotic complete stricture after liver transplantation. 展开更多
关键词 Liver transplantation Anastomosis stricture Endoscopic radiologic rendezvous Duodenal bulb
下载PDF
Influence of Hydrogen on Dislocation Structure in a Duplex Stainless Steel
15
作者 何建宏 唐祥云 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 1990年第3期173-176,共4页
The dislocation structure of specimens of a duplex stainless steel with precharged hydrogen has been investigated by transmission electron microscopy.The result showed the hydrogen acti- vated dislocation source on ph... The dislocation structure of specimens of a duplex stainless steel with precharged hydrogen has been investigated by transmission electron microscopy.The result showed the hydrogen acti- vated dislocation source on phase boundaries of ferrite/austenite and makes certain dislocations in austenite grains move.The dislocation appearances in each phase in specimens uncharged with hydrogen have been given for comparison. 展开更多
关键词 duplex stainless steel hydrogen in duced softening dislocation struc ture
下载PDF
Virtual 5G Network Embedding in a Heterogeneous and Multi-Domain Network Infrastructure 被引量:6
16
作者 Cunqian Yu Weigang Hou +2 位作者 Yingying Guan Yue Zong Pengxing Guo 《China Communications》 SCIE CSCD 2016年第10期29-43,共15页
The pursuit of the higher performance mobile communications forces the emergence of the fifth generation mobile communication(5G). 5G network, integrating wireless and wired domain, can be qualified for the complex vi... The pursuit of the higher performance mobile communications forces the emergence of the fifth generation mobile communication(5G). 5G network, integrating wireless and wired domain, can be qualified for the complex virtual network work oriented to the cross-domain requirement. In this paper, we focus on the multi-domain virtual network embedding in a heterogeneous 5G network infrastructure, which facilitates the resource sharing for diverse-function demands from fixed/mobile end users. We proposed the mathematical ILP model for this problem.And based on the layered-substrate-resource auxiliary graph and an effective six-quadrant service-type-judgment method, 5G embedding demands can be classified accurately to match different user access densities. A collection of novel heuristic algorithms of virtual 5G network embedding are proposed. A great deal of numerical simulation results testified that our algorithm performed better in terms of average blocking rate, routing latency and wireless/wired resource utilization, compared with the benchmark. 展开更多
关键词 5G virtual network embedding heterogeneous and multi-domain infrastructure wireless channel capacity data center
下载PDF
SOSNet:一种非对称编码器-解码器结构的非小细胞肺癌CT图像分割模型 被引量:2
17
作者 谢娟英 张凯云 《电子学报》 EI CAS CSCD 北大核心 2024年第3期824-837,共14页
非小细胞肺癌严重损害人类健康,早期非小细胞肺癌CT(Computed Tomography)图像中的肿瘤结节体积小,不易发现,极易造成漏诊和误诊.为了精确分割非小细胞肺癌CT图像中的小体积肿瘤结节,本文提出SOSNet(Small Object Segmentation Networks... 非小细胞肺癌严重损害人类健康,早期非小细胞肺癌CT(Computed Tomography)图像中的肿瘤结节体积小,不易发现,极易造成漏诊和误诊.为了精确分割非小细胞肺癌CT图像中的小体积肿瘤结节,本文提出SOSNet(Small Object Segmentation Networks)自动分割模型,利用ResNet(Residual Network)基础层和空洞卷积构造非对称编码器-解码器结构作为分割主网络,利用轴向取反注意力模块ARA(Axial Reverse Attention)逐步擦除背景中对分割有影响的结构,再使用结构细化模块SR(Structure Refinement)对主网络输出的粗略特征图进行结构细化,从而实现非小细胞肺癌肿瘤结节分割.在非小细胞肺癌公开数据集的实验测试表明,本文提出的小目标自动分割模型SOSNet可以有效分割出非小细胞肺癌CT图像中的小体积肿瘤结节,其mDice(mean-Dice)、mIoU(mean Intersection over Union)、Sensitivity、F1、Specificity、平均绝对误差MAE(Mean Absolute Error)均优于当前最先进的小目标分割模型CaraNet(Context Axial Reverse Attention Network). 展开更多
关键词 小目标分割 非小细胞肺癌 非对称编码器-解码器 结构细化 轴向取反注意力 CT图像 深度学习 卷积
下载PDF
西北江下游河流底栖动物群落健康评价
18
作者 肖许沐 马卓荦 +1 位作者 蒋任飞 王赛 《环境监测管理与技术》 CSCD 北大核心 2024年第4期30-35,共6页
2020年12月在西北江下游河流设置11个采样点,调查底栖动物群落结构,应用底栖动物完整性指数(B-IBI)评价河流健康状况,并分析B-IBI值与环境因子的关系。结果表明,参照点位的B-IBI值在0.59~4.00之间,处于中等—优状态;受损点位的B-IBI值在... 2020年12月在西北江下游河流设置11个采样点,调查底栖动物群落结构,应用底栖动物完整性指数(B-IBI)评价河流健康状况,并分析B-IBI值与环境因子的关系。结果表明,参照点位的B-IBI值在0.59~4.00之间,处于中等—优状态;受损点位的B-IBI值在0~0.82之间,处于很差—良好状态,其中较差和很差状态占比为87.5%。氨氮浓度与B-IBI值呈现极显著的负相关性,降低水污染负荷是促进底栖动物群落恢复健康的有效途径。在水质已经实现好转的基础上,可通过营造河底卵石生境来促进底栖动物群落恢复,同时也应加强河岸带的修复。 展开更多
关键词 底栖动物 群落结构 底栖动物完整性指数(B-IBI) 河流健康评价 西北江下游
下载PDF
Formation of Hybrid Ring Structure of Cyanurate/Isocyanurate in the Reaction be-tween 2,4,6-Tris(4-Phenyl-Phenoxy)-1, 3,5-Triazine and Phenyl Glycidyl Ether
19
作者 Daisuke Ohno Kazuya Zenyoji +2 位作者 Youji Kurihara Kazuyoshi Ueda Hitoshi Habuka 《International Journal of Organic Chemistry》 CAS 2016年第2期117-125,共9页
Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound w... Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy. 展开更多
关键词 Reaction products of 2 4 6-tris(4-phenyl-phenoxy)-1 3 5-triazine derived from 4-phenylphenol cya-nate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring struc-ture through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.
下载PDF
Study on Microcrystaline Structure and Luminescence of ZnS Thin Film Devices
20
作者 WANG Yu-jiang, CHEN Mou-zhi, SUN Zhen-ning, LIU Rui-ta ng, LI Jie, CHEN Shang-wei (Department of Physics, Xiamen University, Xiamen 361005, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期176-177,共1页
The Electroluminescence thin films of zinc sulfide do ped with erbium, fabricated by thermal evaporation with two boats, are analyzed by the technology of X-ray diffraction (XRD) and X-ray photoelectron spectrosc opy ... The Electroluminescence thin films of zinc sulfide do ped with erbium, fabricated by thermal evaporation with two boats, are analyzed by the technology of X-ray diffraction (XRD) and X-ray photoelectron spectrosc opy (XPS). The relationship between electroluminescence brightness and microst ructure of the thin films is obtained. The analysis results of XRD indicate th at the fabricated zinc sulfide thin films belong to the blende structure and hav e a trend of preferential orientation. The XPS measurements reveal the surface m icrostructure states formed mainly by oxygen absorption and carbon absorption th at effect on the EL excitation and relaxation luminescence process. The maximum photoelectron peak corresponding to the doped erbium is detected at a depth of 1 35nm to 350nm that formed the activation layer in the films. Analysis shows that the high brightness of the film devices is attributed to the crystalline planes of growth orientated in the (311), (400). In explanation of this phenomenon, th e status of the substitute energy for Er 3+ replacing Zn 2+ in the hos t lattice of zinc sulfide is discussed. All results of describing above are referable in researching of the electroluminescence excitation machnism of the t hin film devices and in favor of fabricating the thin film devices with high qua lity. 展开更多
关键词 ELECTROLUMINESCENCE ZNS thin film microstru cture
下载PDF
上一页 1 2 145 下一页 到第
使用帮助 返回顶部