期刊文献+
共找到75篇文章
< 1 2 4 >
每页显示 20 50 100
Dual-channel redox reactions for photocatalytic H_(2)-evolution coupled with photoreforming oxidation of waste materials
1
作者 Huan Liu Shaoxiong He +4 位作者 Jiafu Qu Yahui Cai Xiaogang Yang Chang Ming Li Jundie Hu 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第10期1-39,共39页
Dual-channel redox reaction system is advantageous for photocatalytic hydrogen(H_(2))production when coupled with photoreforming oxidation of waste materials,benefiting both thermodynamically and kinetically.However,e... Dual-channel redox reaction system is advantageous for photocatalytic hydrogen(H_(2))production when coupled with photoreforming oxidation of waste materials,benefiting both thermodynamically and kinetically.However,existing reviews primarily focus on specific oxidation reactions,such as oxidative organic synthesis and water remediation,often neglecting recent advancements in plastic upgrading,biomass conversion,and H_(2)O_(2)production,and failing to provide an in-depth discussion of catalytic mechanisms.This review addresses these gaps by offering a comprehensive overview of recent advancements in dual-channel redox reactions for photocatalytic H_(2)-evolution and waste photoreforming.It highlights waste-to-wealth design concepts,examines the challenges,advantages and diverse applications of dual-channel photocatalytic reactions,including photoreforming of biomass,alcohol,amine,plastic waste,organic pollutants,and H_(2)O_(2)production.Emphasizing improvement strategies and exploration of catalytic mechanisms,it includes advanced in-situ characterization,spin capture experiments,and DFT calculations.By identifying challenges and future directions in this field,this review provides valuable insights for designing innovative dual-channel photocatalytic systems. 展开更多
关键词 PHOTOCATALYSIS DUAL-CHANNEL Hydrogen evolution Photoreforming oxidation In situ characterization
下载PDF
兵家哲学:《孙子兵法》决策原则分析 被引量:2
2
作者 张森年 《学海》 2002年第1期54-58,共5页
谋略思想 ,亦即决策理论 ,是《孙子兵法》的核心内容及其精华之所在。本文从十个方面对贯穿全书的决策原则进行了系统梳理和详细分析。认为 ,《兵法》所提出的决策要符合民众的利益、一切决策必须以客观实际为基础、决策者要全面地辩证... 谋略思想 ,亦即决策理论 ,是《孙子兵法》的核心内容及其精华之所在。本文从十个方面对贯穿全书的决策原则进行了系统梳理和详细分析。认为 ,《兵法》所提出的决策要符合民众的利益、一切决策必须以客观实际为基础、决策者要全面地辩证地考虑各种因素 ,选择最优方案 ,务求“全胜” ,在实施决策过程中 ,对实施决策主体要予以关心、要重视决策反馈 ,因时因地调整决策方案以及要重视决策者素质的提高、品性的修养 ,决策者必须具有广博的知识并必须精通各种机变的运用 ,通“九变之利”等决策原则 。 展开更多
关键词 《孙子兵法》 决策原则 "" 谋胜
下载PDF
Study on the Price Design and Contract Stability of "Company + Farmer" Model with Time Preference under Double Moral Hazards
3
作者 高阔 甘筱青 《Agricultural Science & Technology》 CAS 2014年第8期1424-1427,共4页
The double moral hazard of "company + farmer" and the time preference cost of company and farmer was analyzed. According to static game model, it re-vealed that the reason for low compliance rate of "company + fa... The double moral hazard of "company + farmer" and the time preference cost of company and farmer was analyzed. According to static game model, it re-vealed that the reason for low compliance rate of "company + farmer" model was the existence of market risk, namely, the fluctuation of market price, and the stable market price in contracts was actualy a kind of interval, instead of a specific value. Furthermore, the effect of default penalty, market transaction cost and time prefer-ence cost on the stability of contract was studied. The results showed that default penalty, market transaction cost and time preference cost had positive influence on the price interval range of a contract. 展开更多
关键词 "Company+ farmer" Double moral hazard Time preference Price design Contract stability
下载PDF
On simulation of precise orbit determination of HY-2 with centimeter precision based on satellite-borne GPS technique 被引量:4
4
作者 郭金运 秦建 +1 位作者 孔巧丽 李国伟 《Applied Geophysics》 SCIE CSCD 2012年第1期95-107,117,共14页
The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so t... The HY-2 satellite carrying a satellite-borne GPS receiver is the first Chinese radar altimeter satellite, whose radial orbit determination precision must reach the centimeter level. Now HY-2 is in the test phase so that the observations are not openly released. In order to study the precise orbit determination precision and procedure for HY-2 based on the satellite- borne GPS technique, the satellite-borne GPS data are simulated in this paper. The HY-2 satellite-borne GPS antenna can receive at least seven GPS satellites each epoch, which can validate the GPS receiver and antenna design. What's more, the precise orbit determination processing flow is given and precise orbit determination experiments are conducted using the HY-2-borne GPS data with both the reduced-dynamic method and the kinematic geometry method. With the 1 and 3 mm phase data random errors, the radial orbit determination precision can achieve the centimeter level using these two methods and the kinematic orbit accuracy is slightly lower than that of the reduced-dynamic orbit. The earth gravity field model is an important factor which seriously affects the precise orbit determination of altimeter satellites. The reduced-dynamic orbit determination experiments are made with different earth gravity field models, such as EIGEN2, EGM96, TEG4, and GEMT3. Using a large number of high precision satellite-bome GPS data, the HY-2 precise orbit determination can reach the centimeter level with commonly used earth gravity field models up to above 50 degrees and orders. 展开更多
关键词 HY-2 satellite satellite-borne GPS technique precise orbit determination reduced-dynamic method kinematic geometry method
下载PDF
Single-trial evoked brain responses modeled by multichannel matching pursuit
5
作者 江海腾 卢青 +2 位作者 韩颖琳 姚志剑 刘刚 《Journal of Southeast University(English Edition)》 EI CAS 2010年第4期546-549,共4页
A multichannel matching pursuit(MMP)algorithm is proposed to decompose the one-dimensional multichannel non-stationary magnetoencephalography(MEG)signal at a single-trial level.The single-channel matching pursuit... A multichannel matching pursuit(MMP)algorithm is proposed to decompose the one-dimensional multichannel non-stationary magnetoencephalography(MEG)signal at a single-trial level.The single-channel matching pursuit(MP)linearly decomposes the signal into a set of Gabor atoms,which are adaptively chosen from an overcomplete dictionary with good time-frequency characters.The MMP is the extension of the MP,which represents multichannel signals using linear combination of Gabor atoms with the same occurrence,frequency,phase,and time width,but varying amplitude in all channels.The results demonstrate that the MMP can optimally reconstruct the original signal and automatically remove artifact noises.Moreover,the coherence between the 3D source reconstruction and the prior knowledge of psychology further suggests that the MMP is effective in MEG single-trial processing. 展开更多
关键词 magnetoencephalography(MEG) single trial multichannel matching pursuit source reconstruction
下载PDF
Persistent toxic substances in urban highway runoff in Shanghai
6
作者 张海平 滕俊伟 +1 位作者 姜月 尹秋晓 《Journal of Southeast University(English Edition)》 EI CAS 2014年第2期251-254,共4页
Urban highway runoff samples from seventeen rainfall events were collected in Shanghai in 2011. The concentrations of ten heavy metals and sixteen polycyclic aromatic hydrocarbons PAHs are analyzed. The results show t... Urban highway runoff samples from seventeen rainfall events were collected in Shanghai in 2011. The concentrations of ten heavy metals and sixteen polycyclic aromatic hydrocarbons PAHs are analyzed. The results show that the heavy metal concentrations range within 0.50 to 51.80 As 0 to 20.80 Se 13.67 to 445.80 Zn 0 to 44.20 Pb 0 to 15.80 Ni 39.58 to 264.20 Fe 0 to 253.00 Mn 0 to 8.20 Cr 0 to 124.20 Cu and 159.83 to 536.40 μg/L Al . Se Pb Mn and Al concentrations in most samples exceed their corresponding criterion continuous concentrations CCCs while Zn and Cu concentrations exceed their criterion maximum concentrations CMCs .The concentrations ofΣPAHs range within 37.25 to 114.57 ng/L and concentrations of PAHs are all below their corresponding CCCs.Cu Zn and ΣPAHs show the first flush phenomenon. Analysis results of the modified Nemerow index method NIM indicate that runoff from eight rainfall events may have very strong biological toxicity effects four have strong effects three have moderate effects and only two have insignificant effects.Therefore it is concluded that urban highway runoff is a significant pollution source to aquatic ecosystems and needs immediate purification. 展开更多
关键词 highway runoff heavy metal PAHS Nemerowindex method TOXICITY
下载PDF
Foregut duplication cysts of the stomach with respiratory epithelium 被引量:12
7
作者 Theodosios Theodosopoulos Athanasios Marinis +4 位作者 Konstantinos Karapanos Georgios Vassilikostas Nikolaos Dafnios Lazaros Samanides Εleni Carνounis 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第8期1279-1281,共3页
Gastrointestinal duplication is a congenital rare disease entity. Gastric duplication cysts seem to appear even more rarely. Herein, two duplications cysts of the stomach in a 46 year-old female patient are presented.... Gastrointestinal duplication is a congenital rare disease entity. Gastric duplication cysts seem to appear even more rarely. Herein, two duplications cysts of the stomach in a 46 year-old female patient are presented. Abdominal computed tomography demonstrated a cystic lesion attached to the posterior aspect of the gastric fundus, while upper gastrointestinal endoscopy was negative. An exploratory laparotomy revealed a non-communicating cyst and a smaller similar cyst embedded in the gastrosplenic ligament. Excision of both cysts along with the spleen was performed and pathology reported two smooth muscle coated cysts with a pseudostratified ciliated epithelial lining (respiratory type). 展开更多
关键词 GASTRIC CYST FOREGUT DUPLICATION RESPIRATORY
下载PDF
Scenic Beauty Estimation of Greenbelts in Arterial Roads in Chongqing City 被引量:4
8
作者 张平 艾乔 朱华明 《Agricultural Science & Technology》 CAS 2013年第10期1432-1435,共4页
In the research, trees along 42 roads in Chongqing were explored and es- timated in terms of aesthetics, and aesthetic tendency and major influential factors of aesthetic value of street greenbelts in Chongqing arteri... In the research, trees along 42 roads in Chongqing were explored and es- timated in terms of aesthetics, and aesthetic tendency and major influential factors of aesthetic value of street greenbelts in Chongqing arterial roads were estimated with phychophysical method to establish SBE model of arterial road greenbelts land- scape. 展开更多
关键词 Street trees CHONGQING Evaluation on landscape beauty
下载PDF
Earth Gravity Field Recovered from CHAMP Science Orbit and Accelerometer Data 被引量:2
9
作者 ZHOU Xuhua WU Bin +1 位作者 PENG Bibo XU Houze 《Geo-Spatial Information Science》 2006年第4期250-254,共5页
The earth gravity field model CDS01S of degree and order 36 has been recovered from the post processed Science Orbits and on-board accelerometer data of GFZ’s CHAMP satellite. The model resolves the geoid with an acc... The earth gravity field model CDS01S of degree and order 36 has been recovered from the post processed Science Orbits and on-board accelerometer data of GFZ’s CHAMP satellite. The model resolves the geoid with an accuracy of better than 4 cm at a resolution of 700 km half-wavelength. By using the degree difference variances of geopotential coefficients to compare the model CDS01S with EIGEN3P, EIGEN1S and EGM96, the result indicates that the coefficients of CDS01S are most close to those of EIGEN3P. The result of the comparison between the accuracies of geopotential coefficients in the above models, indicates that the accuracy of coefficients in CDS01S is higher than that in EGM96.The geoid undulations of CDS01S and GGM01C up to 30 degrees are calculated and the standard deviation is 4.7 cm between them. 展开更多
关键词 CHAMP satellite accelerometer and orbit data Earth gravity field geoid CLC NUMBER P223
下载PDF
Analysis of Culture and Drug Sensitivity Tests of Mycoplasmas for 387 Patients with Nongonococcal Urethritis (Cervicitis) in Chongqing
10
作者 翟志芳 郝飞 +3 位作者 钟白玉 黄秀英 唐书谦 刁庆春 《Chinese Journal of Sexually Transmitted Infections》 2004年第2期126-129,i005,共5页
Objective: To investigate the prevalence of myco-plasma infections and the sensitivity to antibiotics among patients with nongonococcal urethritis or cer-vicitis (NGU) in Chongqing. Methods: 387 NGU cases with mycopla... Objective: To investigate the prevalence of myco-plasma infections and the sensitivity to antibiotics among patients with nongonococcal urethritis or cer-vicitis (NGU) in Chongqing. Methods: 387 NGU cases with mycoplasma-positive results upon culture were analysed retrospectively. RESULTS: The majority of patients with mycoplasma infections were in the 20-40 year old age group. No significant difference was found between males and females. Ureaplasma urealyticum is the main pathogen of these NGU cases and no clear relationship between its concentration and pathogenic ability was noted. Drug sensitivity was tested against nine antibiotics; the sensitivity rates to josamycim, minocycline and doxycycline were 94.06%, 88.89% and 86.82% respectively, while the resistance rates to lincomycin, ofloxacin, azithromycin and roxthromycin were 74.94%, 42.12%, 41.60% and 40.31% in turn. Conclusions: Josamycin, minocycline and doxycycline could be used as the first choice to treat NGU with mycoplasma infections in Chongqing. It is important to select antibiotics for NGU treatment with mycoplasma infections based on the results of drug sensitivity tests. 展开更多
关键词 nongonococcal urethritis MYCOPLASMA drug sensitivity
下载PDF
Reducing Influence of Gravity Model Error in Precise Orbit Determination of Low Earth Orbit Satellites 被引量:2
11
作者 GUO Jinlai HU Min ZHAO Qile GUO Daoyu 《Geo-Spatial Information Science》 2007年第2期105-110,共6页
Based on the orbit integration and orbit fitting method, the influence of the characters of the gravity model, with different precisions, on the movement of low Earth orbit satellites was studied. The way and the effe... Based on the orbit integration and orbit fitting method, the influence of the characters of the gravity model, with different precisions, on the movement of low Earth orbit satellites was studied. The way and the effect of absorbing the influence of gravity model error on CHAMP and GRACE satellite orbits, using linear and periodical empirical acceleration models and the so-called "pseudo-stochastic pulses" model, were also analyzed. 展开更多
关键词 precise orbit determination gravity model orbit fitting
下载PDF
Charge transfer and orbital reconstruction of non‐noble transition metal single‐atoms anchored on Ti_(2)CT_(x)‐MXenes for highly selective CO_(2) electrochemical reduction 被引量:3
12
作者 Neng Li Jiahe Peng +2 位作者 Zuhao Shi Peng Zhang Xin Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第7期1906-1917,共12页
Inspired by MXene nanosheets and their regulation of surface functional groups,a series of Ti_(2)C‐based single‐atom electrocatalysts(TM@Ti_(2)CT_(x),TM=V,Cr,Mn,Fe,Co,and Ni)with two dif‐ferent functional groups(T=... Inspired by MXene nanosheets and their regulation of surface functional groups,a series of Ti_(2)C‐based single‐atom electrocatalysts(TM@Ti_(2)CT_(x),TM=V,Cr,Mn,Fe,Co,and Ni)with two dif‐ferent functional groups(T=–O and–S)was designed.The CO_(2)RR catalytic performance was stud‐ied using well‐defined ab initio calculations.Our results show that the CO_(2) molecule can be more readily activated on TM@Ti_(2)CO_(2) than the TM@Ti_(2)CS_(2) surface.Bader charge analysis reveals that the Ti_(2)CO_(2) substrate is involved in the adsorption reaction,and enough electrons are injected into the 2π*u orbital of CO_(2),leading to a V‐shaped CO_(2) molecular configuration and partial negative charge distribution.The V‐shaped CO_(2) further reduces the difficulty of the first hydrogenation reac‐tion step.The calculatedΔG of the first hydrogenation reaction on TM@Ti_(2)CO_(2) was significantly lower than that of the TM@Ti_(2)CS_(2) counterpart.However,the subsequent CO_(2) reduction pathways show that the UL of the potential determining step on TM@Ti_(2)CS_(2) is smaller than that of TM@Ti_(2)CO_(2).Combining the advantages of both TM@Ti_(2)CS_(2) and TM@Ti_(2)CO_(2),we designed a mixed functional group surface with–O and–S to anchor TM atoms.The results show that Cr atoms an‐chored on the surface of mixed functional groups exhibit high catalytic activity for the selective production of CH4.This study opens an exciting new avenue for the rational design of highly selec‐tive MXene‐based single‐atom CO_(2)RR electrocatalysts. 展开更多
关键词 TM@Ti_(2)CTx MXene Single‐atom catalyst CO_(2)RR Orbital reconstruction Charge transform Mixed functional group surface
下载PDF
Weight Based Channel Selection Towards 5G in the Unlicensed Spectrum 被引量:1
13
作者 Yu Zeng Ting Zhou +3 位作者 Honglin Hu Yang Yang Jinfeng Tian Zhenhong Li 《China Communications》 SCIE CSCD 2018年第8期54-66,共13页
The growth of the wireless and mobile communication data traffic has brought severe challenges to the present telecommu- nication systems. To meet the ever-increasing mobile traffic demand in the next 5th generation ... The growth of the wireless and mobile communication data traffic has brought severe challenges to the present telecommu- nication systems. To meet the ever-increasing mobile traffic demand in the next 5th generation (SG) communication systems, deploying 5G in the unlicensed spectrum (SG-U), has been regarded as a promising technology. The Third Generation Partnership Project (3GPP) has specified the standardization of the Li- censed Assisted Access (LAA) and its extension enhanced LAA (eLAA), to opportunistically transmit in the unlicensed spectrum. The LAA/eLAA systems share unlicensed spectrum resource with other networks, e.g., the Wi-Fi systems. In this article, we analyze the coexistence between the eLAA and the Wi-Fi systems in the unlicensed spectrum. We firstly establish the system model where the eLAA coexists with the Wi-Fi systems. Then, we theoretically derive and figure out the unfairness in the multi-channel occupancy rate between the eLAA and the Wi-Fi systems. After that, we propose a weight based channel selection method to improve the fairness of the coexistence. The numerical results demonstrate that by avoiding contentions and declining collisions, our method not only enhances the fairness, but also improves the overall unlicensed spectrum usage rate. 展开更多
关键词 5G unlicensed spectrum eLAA WI-FI multi-channel transmission
下载PDF
Investigation of the active components and mechanism of Sanao Decoction in treating chronic cough by network pharmacology and molecular docking 被引量:2
14
作者 SHENG Mengke LIU Xing +4 位作者 LIAO Yuyao LI Zhixun LYU Lijing YANG Jiaqi SHI Xinyuan 《Digital Chinese Medicine》 2021年第3期191-201,共11页
Objective To investigate the active components and mechanism of Sanao Decoction(三拗汤,SAD)in treating chronic cough based on network pharmacology and molecular docking.Methods Active components and their targets were... Objective To investigate the active components and mechanism of Sanao Decoction(三拗汤,SAD)in treating chronic cough based on network pharmacology and molecular docking.Methods Active components and their targets were obtained from the Traditional Chinese Medicine Systems and Pharmacology Database and Analysis Platform(TCMSP),Bioinformatics Analysis Tool for Molecular mech ANism of Traditional Chinese Medicine(BATMAN-TCM)database,and the literature.The component-target regulatory network and protein-protein interaction(PPI)network were constructed by Cytoscape 3.7.2,and a bioinformatics analysis was performed to identify the significant pathways and their relevant targets.Molecular docking of the core active components and relevant targets was performed.Results A total of 98 active components of SAD and the corresponding 113 drug targets were identified.The component-target regulatory network and PPI network were successfully established.Results of the bioinformatics analysis indicated that 2281 Gene Ontology(GO)terms were enriched in chronic cough,including 2062 terms were in biological processes,77 in cellular components,and 142 in molecular functions,and top 20 significant pathways in Kyoto Encyclopedia of Genes and Genomes(KEGG)analysis.Molecular docking study demonstrated that quercetin,luteolin,kaempferol,and naringenin were in good agreement with the corresponding targets.Conclusion The active compounds of SAD,such as quercetin,luteolin,kaempferol,and naringenin,may act on AKT1,MAPK1,RELA,EGFR,and Bcl-2 and regulate the PI3 K-Akt signaling pathway,AGE-RAGE signaling pathway,and fluid shear stress and atherosclerosis pathway to exert the effects of anti-inflammatory,anti-airway remodeling,anti-oxidant stress effects,and repair airway damage,thus treating chronic cough. 展开更多
关键词 Sanao Decoction(三拗汤 SAD) Chronic cough Network pharmacology Molecular docking Anti-airway remodeling Anti-oxidant stress Repair airway damage
下载PDF
Colon interposition for esophageal reconstruction: A report of 46 cases
15
作者 孙耀昌 徐志飞 +3 位作者 李建秋 赵学维 钟镭 秦雄 《Journal of Medical Colleges of PLA(China)》 CAS 2002年第4期296-298,共3页
Objective:To evaluate the role of colonic interposition for reconstruction of the esophagus. Meth-ods: From April 1979 to October 1998, Thirty-one patients with benign esophageal stenosis and 15 patients with esophag... Objective:To evaluate the role of colonic interposition for reconstruction of the esophagus. Meth-ods: From April 1979 to October 1998, Thirty-one patients with benign esophageal stenosis and 15 patients with esophagus carcinoma received the colonic interposition for esophageal reconstruction. There were 5 pa-tients with the esophagus carcinoma after subtotal gastrectomy. Four of 5 cases received colonic interposition graft from the esophageal bed after the esophagus was pulled out without thoracotomy. Results: There was no perioperative death. All 31 cases of the benign esophageal stenosis got long term survival and normal life. The 3- and 5-year survival rates of patients with the carcinoma of the esophagus were 63. 6% and 40. 6% re-spectively. Conclusion: The colonic interposition graft is a choice for the patients with the cervical stenosis of the esophagus, especially for those already had subtotal gastrectomy. Using the left colonic artery as the sup-porting vessel and using the colon segment in an isoperistaltic position is the optimal choice. Improving the operative techniques and decreasing the complications are important for the extension use of this method. 展开更多
关键词 COLON ESOPHAGEAL RECONSTRUCTION
下载PDF
ESTIMATION OF BASIS EXPANSION MODELS FOR DOUBLY SELECTIVE CHANNELS
16
作者 Liu Yingnan Gao Yonghui +1 位作者 Zhang Nu Liang Qinglin 《Journal of Electronics(China)》 2008年第1期115-119,共5页
By analyzing the relationship between Basis Expansion Model (BEM) and Doppler spectrum, this letter proposed a quasi-MMSE-based BEM estimation scheme for doubly selective channels. Based on the assumption that the bas... By analyzing the relationship between Basis Expansion Model (BEM) and Doppler spectrum, this letter proposed a quasi-MMSE-based BEM estimation scheme for doubly selective channels. Based on the assumption that the basis coefficients are approximately independent and have the same variance for the same channel tap, the quasi-MMSE estimation shows approximately optimal performance and is robust to noise. Moreover, it can avoid a high Peak-to-Average Power Ratio (PAPR) by using continuous pilots. Performance of the proposed estimation scheme has been shown with computer simulations. 展开更多
关键词 Channel estimation Doubly selective channel Basis Expansion Model (BEM) Meansquare error
下载PDF
Gradient based restoration of coal mine images obtained by underground wireless transmissions 被引量:2
17
作者 Lu Zhaolin Qian Jiansheng Li Leida 《Mining Science and Technology》 EI CAS 2011年第6期809-813,共5页
Curvature-driven diffusion (CDD) principles were used to develop a novel gradient based image restora- tion algorithm. The algorithm fills in blocks of missing data in a wireless image after transmission through the n... Curvature-driven diffusion (CDD) principles were used to develop a novel gradient based image restora- tion algorithm. The algorithm fills in blocks of missing data in a wireless image after transmission through the network. When images are transmitted over fading channels, especially in the severe circum- stances of a coal mine, blocks of the image may be destroyed by the effects of noise. Instead of using com- mon retransmission query protocols the lost data is reconstructed by using the adaptive curvature-driven diffusion (ACDD) image restoration algorithm in the gradient domain of the destroyed image. Missing blocks are restored by the method in two steps: In step one, the missing blocks are filled in the gradient domain by the ACDD algorithm; in step two, and the image is reconstructed from the reformed gradients by solving a Poisson equation. The proposed method eliminates the staircase effect and accelerates the convergence rate. This is demonstrated by experimental results. 展开更多
关键词 Image restoration Curvature-driven diffusion Gradient domain Wireless image transmission Poisson equation
下载PDF
Three new species of Parandrexis(Coleoptera:Parandrexidae) from the Middle Jurassic Jiulongshan Formation of Inner Mongolia,China
18
作者 陆塘梅 赵云云 +1 位作者 史宗冈 任东 《Entomotaxonomia》 CSCD 2015年第2期111-122,共12页
Three well-preserved fossil species ofParandrexis longicornis Lu, Shih & Ren sp. nov., P. agilis Lu, Shih & Ren sp. nov. and P. oblongis Lu, Shih & Ren sp. nov. are described and illustrated from the late Middle Ju... Three well-preserved fossil species ofParandrexis longicornis Lu, Shih & Ren sp. nov., P. agilis Lu, Shih & Ren sp. nov. and P. oblongis Lu, Shih & Ren sp. nov. are described and illustrated from the late Middle Jurassic Jiulongshan Formation of Daohugou in Inner Mongolia Autonomous Region, China. These new species are distinguished from other described species of Parandrexis by body size, head dimension (ratio of length to width), pronotum shape, and antennal characters. Based on new morphological data, we emend the generic diagnosis. These findings support the sexual size dimorphism of parandrexids and suggest a gymnosperm sap feeding habit by Parandrexis. 展开更多
关键词 fossil beetle DAOHUGOU sexual size dimorphism feeding habits taxonomy key
下载PDF
Proto-oncogenes expression in the process of asthma airway remodeling
19
作者 刘颖格 戚好文 李焕章 《Journal of Medical Colleges of PLA(China)》 CAS 2002年第1期1-4,共4页
Objective: To observe the expression of proto-oncogenes in the process of airway remodeling in asthma. Methods: Guinea pig was used as an asthma model challenged by ovoglobulin. Dot-blot, Northern-blot molecular hybri... Objective: To observe the expression of proto-oncogenes in the process of airway remodeling in asthma. Methods: Guinea pig was used as an asthma model challenged by ovoglobulin. Dot-blot, Northern-blot molecular hybridization and immunohistochemistry techniques were used to detect the expression of c-fos, c-myc, c-jun and c-sis. Results: Expression of c-fos and c-myc mRNA could not be detected or detected at very low level in the control group. There were greatly increased expression of c-fos and c-myc mRNA after guinea pigs were challenged by ovoglobulin. Thirty minutes after the challenge, the expression of c-fos and c-myc mRNA reached to the peak and returned to normal level 4 h after the challenge. Immunohistochemistry studies showed that Fos, Myc, Jun and Sis expressed at low level in control group and increased after ovoglobulin stimulation. Immunohistochemically positive cells laid in the plasma of airway epithelium, in cell nucleus of bronchial epithelium and in the inflammatory cells. Pathologic studies showed there were smooth muscle thicken around bronchia and lymphocytes infiltration under mucosa or around bronchia smooth muscle. Conclusion: Proto-oncogenes expressed in airway of asthma in a guinea pig model, proto-oncogenes may have roles in the process of airway remodeling. 展开更多
关键词 ONCOGENES ASTHMA airway remodeling
下载PDF
Crystals of suspended marine barite in the eastern equatorial Pacific:processes of dissolution and effects on crystal morphology 被引量:2
20
作者 孙晓霞 杨作升 +1 位作者 范德江 李云海 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第1期194-203,共10页
Suspended particulate substances were sampled in the eastem equatorial Pacific in water column from surface to near bottom in five stations in 2005, from which 868 barite crystals were recovered. The barite crystals w... Suspended particulate substances were sampled in the eastem equatorial Pacific in water column from surface to near bottom in five stations in 2005, from which 868 barite crystals were recovered. The barite crystals were examined under scanning electron microscopy. About 61% of the total barites crystals contained detectable Sr by energy dispersive X-ray spectrometry. Barite crystals could be classified into four groups based on their morphology: 1) bladed; 2) ovoid or rounded; 3) arrow-like; and 4) irregularly shaped. The arrow-like barite crystals in natural environment has never been reported before. In addition, about a half of the studied crystals showed features of dissolution as cavities or holes inside of the crystals or around their edges. We found that differential dissolution of barite crystals is consequence of heterogeneous Sr distribution in barite crystals. Our results would help in understanding the biogeochemical processes of marine barite formation and preservation in seawater and marine sediments. 展开更多
关键词 marine barite crystal morphology Equatorial Pacific preferential dissolution Sr substitution in marine barite
下载PDF
上一页 1 2 4 下一页 到第
使用帮助 返回顶部