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混合动力汽车能效优化与控制策略研究 被引量:1
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作者 付强 《时代汽车》 2024年第5期94-97,共4页
随着环境问题和能源危机的日益严重,混合动力汽车作为一种节能环保的交通工具,得到了广泛关注。能效优化和控制策略是混合动力汽车研究的重要方向,对于提高汽车性能、降低能耗、减少排放具有重要意义。本文旨在探讨混合动力汽车的能效... 随着环境问题和能源危机的日益严重,混合动力汽车作为一种节能环保的交通工具,得到了广泛关注。能效优化和控制策略是混合动力汽车研究的重要方向,对于提高汽车性能、降低能耗、减少排放具有重要意义。本文旨在探讨混合动力汽车的能效优化和控制策略,以提高汽车的整体性能和燃油经济性。 展开更多
关键词 混合动力汽车 能效优化 控制策略 节能环保
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关于西部地区地方财政能力调研报告 被引量:5
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作者 刘尚希 +4 位作者 王志刚 程瑜 梁季 樊轶侠 武靖州 《财政科学》 2018年第2期5-19,共15页
本报告在考察调研省份地方财政收入能力特征的基础上,分析了目前西部地方财政收入能力建设存在的问题和成因,据此提出应对之策。报告认为,西部地区财政能力建设的主要问题包括:(1)经济发展的"资源型"特征大大增加了财政收入... 本报告在考察调研省份地方财政收入能力特征的基础上,分析了目前西部地方财政收入能力建设存在的问题和成因,据此提出应对之策。报告认为,西部地区财政能力建设的主要问题包括:(1)经济发展的"资源型"特征大大增加了财政收入的不确定性和波动性,增加了地方财政的运行风险;(2)地方财政收入高度依赖于投资(尤其是与政府相关的投资项目),限制了地方财政可持续发展能力;(3)营改增后税源与税收分离问题更加突出,地方财政能力的"马太效应"愈发明显。基于财政能力影响因素,提出如下应对之策:(1)让市场在经济发展中发挥决定性作用,构筑地方财政收入能力提升之基;(2)扩大"消费"类税基,弥补西部地区"生产"的不足;(3)完善地方税体系。 展开更多
关键词 地方财政能力 西部地区 消费类税基
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可食性膜在食品保鲜中的应用现状及研究进展 被引量:2
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作者 曾仪雯 周恩弛 +3 位作者 黄高瓴 冯静秋 李丹 张春红 《保鲜与加工》 CAS 2023年第4期62-67,共6页
在食品保鲜领域,可食用天然抗菌保鲜膜是一种重要的可生物降解膜,具有易降解、成本低、来源广等特点。介绍了多糖膜、蛋白膜和脂质膜3种可食性涂膜在食品保鲜中的应用现状,综述了复合成膜技术、纳米颗粒制备技术及添加植物精油在制备可... 在食品保鲜领域,可食用天然抗菌保鲜膜是一种重要的可生物降解膜,具有易降解、成本低、来源广等特点。介绍了多糖膜、蛋白膜和脂质膜3种可食性涂膜在食品保鲜中的应用现状,综述了复合成膜技术、纳米颗粒制备技术及添加植物精油在制备可食性涂膜中的研究进展,以期为可食性包装材料在保鲜领域中的进一步研究提供参考借鉴。 展开更多
关键词 可食性膜 包装 多糖 蛋白质 纳米材料 食品保鲜
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Self-supervised learning artificial intelligence noise reduction technology based on the nearest adjacent layer in ultra-low dose CT of urinary calculi
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作者 ZHOU Cheng LIU Yang +4 位作者 QIU Yingwei HE Daijun YAN Yu LUO Min LEI Youyuan 《中国医学影像技术》 CSCD 北大核心 2024年第8期1249-1253,共5页
Objective To observe the value of self-supervised deep learning artificial intelligence(AI)noise reduction technology based on the nearest adjacent layer applicated in ultra-low dose CT(ULDCT)for urinary calculi.Metho... Objective To observe the value of self-supervised deep learning artificial intelligence(AI)noise reduction technology based on the nearest adjacent layer applicated in ultra-low dose CT(ULDCT)for urinary calculi.Methods Eighty-eight urinary calculi patients were prospectively enrolled.Low dose CT(LDCT)and ULDCT scanning were performed,and the effective dose(ED)of each scanning protocol were calculated.The patients were then randomly divided into training set(n=75)and test set(n=13),and a self-supervised deep learning AI noise reduction system based on the nearest adjacent layer constructed with ULDCT images in training set was used for reducing noise of ULDCT images in test set.In test set,the quality of ULDCT images before and after AI noise reduction were compared with LDCT images,i.e.Blind/Referenceless Image Spatial Quality Evaluator(BRISQUE)scores,image noise(SD ROI)and signal-to-noise ratio(SNR).Results The tube current,the volume CT dose index and the dose length product of abdominal ULDCT scanning protocol were all lower compared with those of LDCT scanning protocol(all P<0.05),with a decrease of ED for approximately 82.66%.For 13 patients with urinary calculi in test set,BRISQUE score showed that the quality level of ULDCT images before AI noise reduction reached 54.42%level but raised to 95.76%level of LDCT images after AI noise reduction.Both ULDCT images after AI noise reduction and LDCT images had lower SD ROI and higher SNR than ULDCT images before AI noise reduction(all adjusted P<0.05),whereas no significant difference was found between the former two(both adjusted P>0.05).Conclusion Self-supervised learning AI noise reduction technology based on the nearest adjacent layer could effectively reduce noise and improve image quality of urinary calculi ULDCT images,being conducive for clinical application of ULDCT. 展开更多
关键词 urinary calculi tomography X-ray computed artificial intelligence prospective studies
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Right heart modified myocardial performance index and ductus venosus spectrum parameters in pre-eclampsia fetuses for predicting adverse pregnancy outcomes
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作者 GAO Jing LI Hezhou +4 位作者 WANG Ming WU Juan WANG Xinxia LIU Yun ZHU Ziqi 《中国医学影像技术》 CSCD 北大核心 2024年第8期1146-1150,共5页
Objective To observe the values of changes of right heart modified myocardial performance index(Mod-MPI)and ductus venosus(DV)spectrum parameters in pre-eclampsia fetuses for predicting adverse pregnancy outcomes.Meth... Objective To observe the values of changes of right heart modified myocardial performance index(Mod-MPI)and ductus venosus(DV)spectrum parameters in pre-eclampsia fetuses for predicting adverse pregnancy outcomes.Methods Eighty-one pregnant women diagnosed as pre-eclampsia were prospectively enrolled and divided into severe pre-eclampsia(SPE)group(n=39)and mild pre-eclampsia(MPE)group(n=42),while 85 healthy pregnant women were taken as controls(control group).Fetal right heart function parameters,including right ventricular isovolumetric relaxation time(IRT),isovolumetric contraction time(ICT),ejection time(ET),total spent time(TST),Mod-MPI,tricuspid valve peak flow velocity ratio in early and late diastole(TV-E/A),as well as blood flow velocities in each waveform of DV spectrum(S,V,D,and A wave)were obtained,and the pulsatility index(PI)and the ratio of blood flow velocities in each waveform of the DV(S/V,S/D,S/A,V/D,V/A,D/A)were calculated.Intrauterine fetal distress,preterm delivery,neonatal asphyxia and newborn with low weight were considered as adverse pregnancy outcomes.The correlations of right heart Mod-MPI and TV-E/A with DV parameters in pre-eclampsia fetuses were assessed,and their predictive efficacies for adverse pregnancy outcomes were evaluated for right heart Mod-MPI and DV using the receiver operating characteristics(ROC)and the area under the curves(AUC).Results Compared with control group and MPE group,fetal right heart IRT,ICT and Mod-MPI increased and ET decreased in SPE group(all P<0.05).No significant differences of right heart TST and TV-E/A among 3 groups(both P>0.05).Fetal DV A-wave velocity and V/D values progressively decreased but PI progressively increased in control,MPE and SPE groups(all P<0.05).Fetal right heart Mod-MPI in pre-eclampsia was moderately positively correlated with DV PI(r=0.637,P=0.016),while TV-E/A was weakly negatively correlated with DV V/D(r=-0.355,P=0.043).Adverse pregnancy outcomes were noticed in 59 pre-eclampsia cases.The AUC of fetal right heart Mod-MPI and DV PI for predicting adverse pregnancy outcomes in pre-eclampsia cases was 0.897 and 0.848,respectively,without significant difference(Z=0.460,P=0.400).Conclusion Changes of right heart Mod-MPI and DV spectrum parameters in pre-eclampsia fetuses had high value for predicting adverse pregnancy outcomes. 展开更多
关键词 PRE-ECLAMPSIA fetal heart ventricular function ultrasonography prenatal prospective studies
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汉语言文学专业学生实践及创新能力的提升与培养 被引量:4
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作者 谭德兴 《中国大学教学》 CSSCI 北大核心 2019年第6期68-71,共4页
汉语言文学专业属传统基础学科,拓展传统基础学科的实践及创新内容也成为当前大学教学与改革的一个重点和难点。贵州大学汉语言文学专业属国家级特色专业、贵州省一流专业、贵州大学品牌特色专业。在近五年的专业建设中,我们从学生原创... 汉语言文学专业属传统基础学科,拓展传统基础学科的实践及创新内容也成为当前大学教学与改革的一个重点和难点。贵州大学汉语言文学专业属国家级特色专业、贵州省一流专业、贵州大学品牌特色专业。在近五年的专业建设中,我们从学生原创能力、学术研究能力和专业认知能力等方面入手,着重提升与培养学生的实践及创新能力,取得了一定成绩,产生了一定影响,为新形势下大学传统基础学科人才培养模式做出了积极探索。 展开更多
关键词 汉语言文学专业 能写 能研 实践 创新
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Fuzzy Words Distribution in Management Science Research Articles 被引量:1
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作者 董艳云 白永权 蒋跃 《Sino-US English Teaching》 2007年第3期37-42,共6页
By using ZHANG Qiao's method for identifying fuzzy words (1998), the present paper makes a statistic analysis of fuzzy words appearing in about 43,000 words of 6 academic research articles in management science. A ... By using ZHANG Qiao's method for identifying fuzzy words (1998), the present paper makes a statistic analysis of fuzzy words appearing in about 43,000 words of 6 academic research articles in management science. A distribution curve of fuzzy words in management research articles is drawn in accordance with the structures of the articles, and it is proved to be reasonable for tile discourse function of each section. Furthermore, the fuzzy words are divided into three categories and eleven sub-categories, including Category Ⅰ-fuzzy words, Category Ⅱ-fuzzy words+non-fuzzy part / non-fuzzy part+fuzzy words, Category Ⅲ-approximators+fuzzy words. Distribution of fuzzy words varies in different sections of research articles in management science, because of different communicative purposes or discourse functions. Introduction section and Conclusion section have a higher occurrence rate of fuzzy words than Abstract section and Methodology and Data section. 展开更多
关键词 academic research articles in management science fuzzy words distribution curve discourse function category research
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Absorptive capacity and R&D strategy of labor-managed firms 被引量:1
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作者 罗建利 仲伟俊 《Journal of Southeast University(English Edition)》 EI CAS 2009年第3期413-418,共6页
Taking absorptive capacity effects on research spillovers into consideration, this paper focuses on the R&D investment decisions and the output decisions of labor-managed firms. Based on the general model of the cost... Taking absorptive capacity effects on research spillovers into consideration, this paper focuses on the R&D investment decisions and the output decisions of labor-managed firms. Based on the general model of the cost-reducing R&D, the strategic interactions of output and R&D investment between labor-managed firms in a duopoly are analyzed. Moreover, the impact of absorptive capacity effects on optimal output in the production stage is discussed. In the R&D stage, the impacts of absorptive capacity effects on the equilibrium R&D investment in cooperative and non-cooperative R&D are analyzed. Finally, the R&D strategy of labor-managed firms is compared with the behavior of profit-maximizing firms. The results show that equilibrium R&D investment is always higher than that in the exogenous spillover rate, which is similar to the behavior of the profit-maximizing firms. However, unlike the profit-maximizing firms, the impact of the absorptive capacity that affects the relationship between the optimal output and its own(rival' s)R&D is shown to be dependent upon a return-to-scale of the production. 展开更多
关键词 absorptive capacity labor-managed firm R&D strategic interaction
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Theoretical Study on Dissociation Potential Energy Surface of Peroxynitric Acid
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作者 韦文美 郑仁慧 +2 位作者 吴允凯 杨帆 洪石 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2014年第6期659-662,I0003,共5页
The lowest energy structures of peroxynitric acid have been studied with B3LYP/6-311+ G(2d,2p) method. The potential energy surfaces (PES) along the O-N and O-O bonds have been scanned at CCSD(T)/aug-cc-pVDZ le... The lowest energy structures of peroxynitric acid have been studied with B3LYP/6-311+ G(2d,2p) method. The potential energy surfaces (PES) along the O-N and O-O bonds have been scanned at CCSD(T)/aug-cc-pVDZ level, respectively. The calculated results show that on the O-N PES, the O3-N4 bond length of the loose transition state is 2.82A^° and the corresponding energy barrier is 25.6 kcal/mol, while on the O-O PES, the loose transition state with of O2-O3 bond length of 2.35A^° has the energy barrier of 37.4 kcal/mol. Thus the primary reaction path for peroxynitric acid is the dissociation into HO2 and NO2. 展开更多
关键词 Peroxynitric acid STRUCTURE Potential energy surface Theoretical study
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Microbiological Transformation of Ginsenoside Rg_1 被引量:14
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作者 董阿玲 崔亚君 +2 位作者 郭洪祝 郑俊华 果德安 《Journal of Chinese Pharmaceutical Sciences》 CAS 2001年第3期115-118,共4页
Forty-nine microbial strains were used to screen their ability for the microbiological transforma-tion of ginsenoside Rg1. Aspergillus niger (3.1858) and Absidia coerulea (3.3538) were found to convert ginsenoside Rg1... Forty-nine microbial strains were used to screen their ability for the microbiological transforma-tion of ginsenoside Rg1. Aspergillus niger (3.1858) and Absidia coerulea (3.3538) were found to convert ginsenoside Rg1 efficiently to less polar metabolites. Preparative scale transformation with both fungi Absidia coerulea (3.3538) and Aspergillus niger (3.1858) have resulted in the production of one same metabolite (MT1). Its structure was char-acterized as 6-O-b-D-glucopyranosyl-20(S)-protopanaxatriol (Ginsenoside Rh1) on the basis of its TOF-MS and 1H, 13C NMR spectral data. The biotransformation kinetic curves for Ginsenoside Rg1 and MT1 were reported for the first time, and the biotransformation pathway was proposed. 展开更多
关键词 Microbiological transformation Ginsenoside Rg1 Ginsenoside Rh1 MICROORGANISM FUNGI
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Construction and Application of Plasmid pUC19-CM-D
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作者 卢福芝 孙靓 +2 位作者 黄靖华 黄艳燕 黄日波 《Agricultural Science & Technology》 CAS 2010年第5期31-33,共3页
[Objective] The aims were to construct a new suicide plasmid of Lactobacillus and gene deletion engineering bacteria of Lactobacillus with pUC19 vector. [Methods] pUC19-CM was constructed by inserting a chloramphenico... [Objective] The aims were to construct a new suicide plasmid of Lactobacillus and gene deletion engineering bacteria of Lactobacillus with pUC19 vector. [Methods] pUC19-CM was constructed by inserting a chloramphenicol resistant gene into the multi-cloning site of pUC19,and then two homologous fragments were cloned into each side of the pUC19-CM to construct suicide plasmid pUC19-CM-D. [Results] A replacement mutant strain,whose target gene was replaced by resistant gene,could be obtained by transforming the suicide plasmid pUC19-CM-D into Lactobacillus for resistance screening. [Conclusion] The construction and application of pUC19-CM-D provided a fast and efficient means of construction of gene deletion engineering bacteria of Lactobacillus,and laid a foundation for study of gene function of Lactobacillus. 展开更多
关键词 Suicide plasmid Lactobacillus Gene knock out
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Research Progress on MEF2B Gene in Human and Animals
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作者 马晓萌 张莉 杜立新 《Agricultural Science & Technology》 CAS 2016年第11期2477-2482,共6页
Myocyte enhancer factor 2B (MEF2B) gene belongs to myocyte enhancer factor 2 (MEF2) gene family. They are all widely expressed in muscle and nerve tissues of human and animals. MEF2B plays an important role in the... Myocyte enhancer factor 2B (MEF2B) gene belongs to myocyte enhancer factor 2 (MEF2) gene family. They are all widely expressed in muscle and nerve tissues of human and animals. MEF2B plays an important role in the growth of muscle, development and differentiation of nerve system and liver fibrosis. This re- view mainly focused on the structural characteristics, tissue distribution, biological functions and research progress of MEF2B gene in human and animals. 展开更多
关键词 Myocyte enhancer factor 2B (MEF2B) Biological functions Tissue dis- tribution Research progress
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Comparison study on calculation methods of bending behavior of Chinese reinforced concrete beams from 1912 to 1949 被引量:1
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作者 淳庆 Van Balen Koenraad 韩宜丹 《Journal of Southeast University(English Edition)》 EI CAS 2015年第4期529-534,共6页
In order to study the calculation methods of bending behavior of Chinese reinforced concrete beams from 1912 to 1949, tests on the mechanical performance of 66 rebars from different modem Chinese concrete buildings, t... In order to study the calculation methods of bending behavior of Chinese reinforced concrete beams from 1912 to 1949, tests on the mechanical performance of 66 rebars from different modem Chinese concrete buildings, the concrete compressive strength of 12 modem Chinese concrete buildings, and the concrete cover thickness of 9 modem Chinese concrete buildings are carried out; and the actual material properties and structural conformations of modem Chinese concrete buildings are obtained. Then, the comparison on calculation methods of bending behavior including the original Chinese calculation method, the present Chinese calculation method, the present American calculation method and the present European calculation method is studied. The results show that the original Chinese calculation method of bending behavior is based on the allowable stress calculation method, and the design safety factors are 3.55 to 4. 0. In term of the calculation area of longitudinal rebars of reinforced concrete beams, without considering earthquake action, the original Chinese structural calculation method is safer than the present Chinese structural calculation method, the present European structural calculation method, and the present American structural calculation method. The results can provide support for the structural safety assessments of modem Chinese reinforced concrete buildings. 展开更多
关键词 reinforced concrete beam the Republic of China era from 1912 to 1949 bending behavior calculation method comparative study
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Influence of Metal Sulfides as Anode Catalysts on Performance of H_2S SOFC 被引量:9
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作者 钟理 刘曼 +1 位作者 韦国林 CHUANG Karl 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第3期245-248,共4页
Two anode catalysts with Pt, MoS2 and composite metal sulfides (MoS2+NiS), are investigated for electrochemical oxidation of hydrogen sulfide in solid oxide fuel cell (SOFC) at temperatures 750-850℃. The catalysts co... Two anode catalysts with Pt, MoS2 and composite metal sulfides (MoS2+NiS), are investigated for electrochemical oxidation of hydrogen sulfide in solid oxide fuel cell (SOFC) at temperatures 750-850℃. The catalysts comprising MoS2 and MoSa+NiS exhibited good electrical conductivity and catalytic activity. MoS2 and composite catalysts were found to be more active than Pt, a widely used catalyst for high temperature H2S/O2 fuel cell at 750-850℃. However, MoS2 itself sublimes above 450℃. In contrast, composite catalysts containing both Mo and transition metal (Ni) are shown to be stable and effective in promoting the oxidation of H2S in SOFC up to 850℃. However, electric contact is poor between the platinum current collecting layer and the composite metal sulfide layer, so that the cell performance becomes worse. This problem is overcome by adding conductive Ag powder into the anode layer (forming MoS2+NiS+Ag anode material) to increase anode electrical conductance instead of applying a thin layer of platinum on the top of anode. 展开更多
关键词 solid oxide fuel cell (SOFC) hydrogen sulfide metal sulfide ANODE
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Identification of novel sense and antisense transcription at the TRPM2 locus in cancer 被引量:2
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作者 Ugo Orfanelli Ann-Kathrin Wenke +3 位作者 Claudio Doglloni Vincenzo Russo Anja Katrin Bosserhoff Giovanni Lavorgna 《Cell Research》 SCIE CAS CSCD 2008年第11期1128-1140,共13页
It has been proposed that in cancer, where the bulk of the genome becomes hypomethylated, there is an increase in transcriptional noise that might lead to the generation of antisense transcripts that could affect the ... It has been proposed that in cancer, where the bulk of the genome becomes hypomethylated, there is an increase in transcriptional noise that might lead to the generation of antisense transcripts that could affect the function of key oncosuppressor genes, ultimately leading to malignant transformation. Here, we describe the computational identification of a melanoma-enriched antisense transcript, TRPM2-AS, mapped within the locus of TRPM2, an ion channel capable of mediating susceptibility to cell death. Analysis of the TRPM2-AS genomic region indicated the presence in the same region of another tumor-enriched TRPM2 transcript, TRPM2-TE, located across a CpG island shared with TRPM2-AS. Quantitative PCR experiments confirmed that TRPM2-AS and TRPM2-TE transcripts were up-regu- lated in melanoma, and their activation was consistent with the methylation status of the shared CpG island. Functional knock-out of TRPM2-TE, as well as over-expression of wild-type TRPM2, increased melanoma susceptibility to apoptosis and necrosis. Finally, expression analysis in other cancer types indicated that TRPM2-AS and TRPM2-TE over-expression might have an even wider role than anticipated, reinforcing the relevance of our computational approach in identifying new potential therapeutic targets. 展开更多
关键词 BIOINFORMATICS TRANSCRIPTION apoptosis ANTISENSE METHYLATION ion channel
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Study on Relationship between Microstructure of Active Phase and HDS Performance of Sulfided Ni-Mo Catalysts: Effect of Metal Loading 被引量:21
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作者 Guo Rong Shen Benxian +3 位作者 Fang Xiangchen Sun Jin Peng Chong Cui Xiaoli 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2014年第2期12-19,共8页
Six Ni-Mo catalysts with different metal contents were prepared and characterized by N2 adsorption and X-ray diffi'actometry. The active phase microstructure of these catalysts was examined by the Raman spectroscopy,... Six Ni-Mo catalysts with different metal contents were prepared and characterized by N2 adsorption and X-ray diffi'actometry. The active phase microstructure of these catalysts was examined by the Raman spectroscopy, temperature- programmed reduction (TPR), X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. Hydrodesulfurization (HDS) activity of catalyst samples were analyzed in a flow fixed-bed microreactor. The sulfidation degree of Mo and the length of the MoS2 slab slightly increased with the amount of metal loaded following sulfidation. This small change is attributed to polymolybdate species observed in all the oxidized catalysts. Weak metal-support interactions, as determined by the TPR technique, increased the NiSx sulfidation phase and MoS2 slab stacking. The HDS activity of the catalyst samples increased with the number of active sites. For high metal loading catalysts, their HDS activity was nearly identical because the sulfur atoms cannot easily approach active sites. This change is caused by the large number of stacked layers in the MoS2 slabs as well as the decrease in the specific surface area and pore volume of the catalyst samples with an increasing metal loading. 展开更多
关键词 Ni-Mo catalysts HYDRODESULFURIZATION SULFIDATION MICROSTRUCTURE metal loading
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Constructivism-based Course Books' Compiling and a New Mode of Teaching
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作者 王玉雯 《Sino-US English Teaching》 2007年第3期1-5,共5页
The paper explores the positive impact of constructivism-based course books compiling and the new mode of teaching, analyzes their effects on helping students improve their integrated English language competence, and ... The paper explores the positive impact of constructivism-based course books compiling and the new mode of teaching, analyzes their effects on helping students improve their integrated English language competence, and pointing out that the development of teaching non-English major graduate students has raised new demands for teaching devices, teaching methodology and new roles of teachers and learners. Therefore, New Century Graduate English Series, as constructivism-based course books, has made some beneficial attempts for the implementation of the new graduate English teaching reauirements. 展开更多
关键词 CONSTRUCTIVISM new mode integrated English language competence New Century GraduateEnglish Series
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Influence of impurities on microstructure and mechanical properties of ZK60 magnesium alloy 被引量:5
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作者 潘复生 毛建军 +2 位作者 陈先华 彭建 王敬丰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第7期1299-1304,共6页
The influence of impurity content on the microstructure and mechanical properties of ZK60 magnesium alloys was investigated by optical microscopy,scanning electron microscopy and tensile test.ZK60 alloys were prepared... The influence of impurity content on the microstructure and mechanical properties of ZK60 magnesium alloys was investigated by optical microscopy,scanning electron microscopy and tensile test.ZK60 alloys were prepared by changing holding time of alloy melt during semi-continuous casting in order to control the content of impurity elements.The alloy with lower purity content is found to have less second precipitates and larger grain size in the as-cast state.However,in the as-extruded state,reducing impurities brings about a decrease in grain size and an increase in yield strength from 244 MPa to 268 MPa,while the elongations in the as-extruded alloys with different contents of impurities are almost the same.After T5 treatment,impurity content is found to have more obvious effect on the yield strength of ZK60 alloy.The yield strength of ZK60-45 alloys with low impurity content is increased up to 295 MPa after T5 treatment. 展开更多
关键词 ZK60 magnesium alloy IMPURITIES mechanical properties MICROSTRUCTURE EXTRUSION T5 treatment
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Preparation and Properties of Diesel Oil Microemulsified Acid 被引量:2
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作者 张赛玉 王芳 +2 位作者 陈彦东 方波 卢拥军 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第2期287-291,共5页
The microemulsified acid system composed by diesel oil, hydrochloric acid and emulsifier was investi- gated in this paper. The stability of microemulsified acid and the phase behavior of the microemulsified system Wer... The microemulsified acid system composed by diesel oil, hydrochloric acid and emulsifier was investi- gated in this paper. The stability of microemulsified acid and the phase behavior of the microemulsified system Were studied. The size distribution and the corrosion inhibition performance were also observed. The results showed that the diesel oil microemulsified acid system possessed small size and good stability under different temperature.The tolerance to CaCl2 reached 80 g·L^-1. Compared with the same concentration hydrochloric acid solution, the corrosion inhibition performance of the diesel oil microemulsified acid system was remarkable. 展开更多
关键词 microemulsified acid emulsified acid acidizing fluid corrosion inhibition
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Physiological diversity of orchids 被引量:10
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作者 Shibao Zhang Yingjie Yang +4 位作者 Jiawei Li Jiao Qin Wei Zhang Wei Huang Hong Hu 《Plant Diversity》 SCIE CAS CSCD 2018年第4期196-208,共13页
The Orchidaceae is a diverse and wide spread family of flowering plants that are of great value in ornamental, medical, conservation, and evolutionary research. The broad diversity in morphology,growth form, life hist... The Orchidaceae is a diverse and wide spread family of flowering plants that are of great value in ornamental, medical, conservation, and evolutionary research. The broad diversity in morphology,growth form, life history, and habitat mean that the members of Orchidaceae exhibit various physiological properties. Epiphytic orchids are often characterized by succulent leaves with thick cell walls,cuticles, and sunken stomata, whereas terrestrial orchids possess rhizomes, corms, or tubers. Most orchids have a long juvenile period, slow growth rate, and low photosynthetic capacity. This reduced photosynthetic potential can be largely explained by CO_2 diffusional conductance and leaf internal structure. The amount of light required for plant survival depends upon nutritional mode, growth form,and habitat. Most orchids can adapt to their light environments through morphological and physiological adjustments but are sensitive to sudden changes in irradiance. Orchids that originate from warm regions are susceptible to chilling temperatures, whereas alpine members are vulnerable to high temperatures.For epiphytic orchids, rapid water uptake by the velamen radicum, water storage in their pseudobulbs and leaves, slow water loss, and Crassulacean Acid Metabolism contribute to plant-water balance and tolerance to drought stress. The presence of the velamen radicum and mycorrhizal fungi may compensate for the lack of root hairs, helping with quick absorbance of nutrients from the atmosphere.Under cultivation conditions, the form and concentration of nitrogen affect orchid growth and flowering.However, the limitations of nitrogen and phosphorous on epiphytic orchids in the wild, which require these plants to depend on mycorrhizal fungi for nutrients throughout the entire life cycle, are not clearly understood. Because they lack endosperm, seed germination depends upon obtaining nutrients via mycorrhizal fungi. Adult plants of some autotrophic orchids also gain carbon, nitrogen, phosphorus, and other elements from their mycorrhizal partners. Future studies should examine the mechanisms that determine slow growth and flower induction, the physiological causes of variations in flowering behavior and floral lifespan, the effects of nutrients and atmospheric-nitrogen deposition, and practical applications of mycorrhizal fungi in orchid cultivation. 展开更多
关键词 ORCHID Ahiotic environments PHOTOSYNTHESIS Morphology MYCORRHIZA
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