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排序方式: 共有73条查询结果,搜索用时 15 毫秒
1.
投影寻踪分类模型在膜下滴灌模式评价中的应用   总被引:4,自引:0,他引:4  
针对综合考虑产量、品质、水分利用效率等指标的灌水模式优选问题,本文提出了融入加速遗传算法的膜下滴灌灌水模式投影寻踪评价模型。该模型通过高维数据向低维空间的转换,把样本的多个评价指标转化成一个综合指标,实现了对膜下滴灌多种灌水模式的评价。最后应用该模型于新疆的大田试验中,对9种灌水模式进行了评价和优选,结果表明,对整体考虑产量、品质、水分利用效率的最优灌水模式的选择与大田实验方案选择相符,能客观、真实地反映各评价指标的贡献率和方向性。  相似文献   
2.
The self-assembly polymerization of ditopic macromolecules via metal–ligand binding is a facile route for the preparation of metallo-supramolecular polymers (MSPs). We herein review our recent work focused on the synthesis and investigation of metallo-supramolecular polymers based on 2,6-bis(1′-methylbenzimidazolyl)pyridine endcapped poly(p-phenylene ethynylene) and poly(p-xylene) macromonomers. These materials are readily solution-processable and display appreciable mechanical properties as well as other attractive properties such as specific opto/electrical functions or high thermal stability. Our work illustrates that metallosupramolecular polymerization offers an attractive approach to assemble high-molecular-weight macromolecules from well-defined, easy to process precursors. Variation of the ditopic ligands and metal ions allows one to easily tailor the desired properties. This paper is dedicated to Professor Ian Manners and his scientific accomplishments.  相似文献   
3.
A series of phenyleneethynylene copolymers with triphenylamine units as hole‐transporting moieties (TPA‐PPEs) were synthesized by the palladium‐catalyzed cross‐coupling polycondensation of diethynyltriphenylamines and selected dihalogen comonomers, for instance substituted benzene, thiophene, benzothiadiazole, or anthracene. Incorporation of the electron‐rich amino group into the PPE backbone does not interrupt the main chain conjugation. Furthermore, it has a decreasing effect on the oxidation potential, thus makes these polymers interesting as hole‐injection/hole‐transporting materials. The chemical structure of the new alternating copolymers was confirmed by 1H and 13C NMR spectroscopy and elemental analysis and gel‐permeation chromatography (GPC; THF, Mn ≈ 15,000–30,000 g/mol) was conducted. Furthermore, their optical properties were investigated by UV/vis spectroscopy. The TPA‐PPEs exhibit absorption maxima at around 400 nm (π‐π*), except anthracene containing copolymer 3f (λmax = 514 nm in THF) and benzothiadiazole containing one 3g (λmax = 503 nm in THF). The TPA copolymers have oxidation potentials about 1.1 V (Ag/AgCl). They are good photoconducting materials ( 3a : IPhoto = 4 × 10?10 A at 425 nm (400 V), 3g : IPhoto = 1.3 × 10?11 A at λmax = 500 nm (20 V)) and show emission after excitation at around 450 nm (560 nm 3f ). Their application in nonoptimized polymer solar cells (bulk heterojunction) led to power conversion efficiencies of around 1–1.8% after illumination with 100 mW/cm2 of AM1.5. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   
4.
王晴岚 《金属学报》2020,25(9):1043-1051
结核病是一种由结核分枝杆菌感染引起的,以空气传播为主的传染病,目前仍是全球公共卫生安全的重大威胁。随着抗结核抗生素的广泛使用,结核病的耐药问题也愈演愈烈,出现了多耐药结核、广泛耐药结核甚至完全耐药结核。对临床用抗结核药物作用机制和结核分枝杆菌对应耐药机制的研究,有利于我们开发新的抗结核药物,改造现有抗结核药物和研发新的耐药诊断技术。本文综述了近年来有关抗结核新药的作用机制及细菌耐药机制的研究进展,并特别讨论了最新发现的结核分枝杆菌外膜通道蛋白PE/PPE蛋白可能在结核分枝杆菌耐药中的重要作用,以期为后续的相关研究提供一定的参考。  相似文献   
5.
Particulate matter (PM) pollution has become a serious public health issue, especially with outbreaks of emerging infectious diseases. However, most present filters are bulky, opaque, and show low-efficiency PM0.3/pathogen interception and inevitable trade-off between PM removal and air permeability. Here, a unique electrospraying–netting technique is used to create spider-web-inspired network generator (SWING) air filters. Manipulation of the dynamic of the Taylor cone and phase separation of its ejected droplets enable the generation of 2D self-charging nanostructured networks on a large scale. The resultant SWING filters show exceptional long-range electrostatic property driven by aeolian vibration, enabling self-sustained PM adhesion. Combined with their Steiner-tree-structured pores (size 200–300 nm) consisting of nanowires (diameter 12 nm), the SWING filters exhibit high efficiency (>99.995% PM0.3 removal), low air resistance (<0.09% atmosphere pressure), high transparency (>82%), and remarkable bioprotective activity for biohazard pathogens. This work may shed light on designing new fibrous materials for environmental and energy applications.  相似文献   
6.
利用扫描电镜、差示扫描量热仪以及高频介电仪研究了聚苯醚(PPE)/环氧树脂(EP)体系的相分离、耐热性和介电性能,并利用质量损失法研究了PPE/EP体系的耐溶剂性,结果表明:PPE/EP混合物的耐热性和介电性能均随着PPE含量的增加而提高,而耐溶剂性则随着PPE含量的增加而降低,在PPE/EP体系中加入三烯丙基异氰酸酯(TAIC)可有效地提高PPE/EP体系的耐溶剂性;当PPE含量大于30%时,PPE/EP混合物的介电性能显著提高,耐溶剂性显著下降。  相似文献   
7.
The extensive development of electronic systems and telecommunications has lead to major concerns regarding electromagnetic pollution. Motivated by environmental questions and by a wide variety of applications, the quest for materials with high efficiency to mitigate electromagnetic interferences (EMI) pollution has become a mainstream field of research. This paper reviews the state-of-the-art research in the design and characterization of polymer/carbon based composites as EMI shielding materials. After a brief introduction, in Section 1, the electromagnetic theory will be briefly discussed in Section 2 setting the foundations of the strategies to be employed to design efficient EMI shielding materials. These materials will be classified in the next section by the type of carbon fillers, involving carbon black, carbon fiber, carbon nanotubes and graphene. The importance of the dispersion method into the polymer matrix (melt-blending, solution processing, etc.) on the final material properties will be discussed. The combination of carbon fillers with other constituents such as metallic nanoparticles or conductive polymers will be the topic of Section 4. The final section will address advanced complex architectures that are currently studied to improve the performances of EMI materials and, in some cases, to impart additional properties such as thermal management and mechanical resistance. In all these studies, we will discuss the efficiency of the composites/devices to absorb and/or reflect the EMI radiation.  相似文献   
8.
刘庆辉 《广东化工》2012,39(15):23-24
结合作者自己管理的建设项目,基于能量意外释放理论,对该类型项目个体防护装备的分类和选择提出了自己的看法,也对类似项目具有借鉴意义。  相似文献   
9.
目的以结核分枝杆菌(Mycobacterium tuberculosis,MTB)RD1区特异性培养滤液蛋白10(culture filtrate pro-tein10,CFP10)与戊糖-5-磷酸-3-差异构象酶68(pentose-5-phosphate-3-epimerase68,PPE68)的融合蛋白CFP10-PPE68作为包被抗原,建立检测结核病患者血清中MTB抗体的间接ELISA法。方法采用亲和层析法纯化重组CFP10-PPE68、CFP10和PPE68蛋白;分别以3种蛋白作为包被抗原,建立检测结核病患者血清中MTB特异性抗体的间接ELISA法;采用方阵滴定法对建立的间接ELISA法的条件进行优化;并以临床诊断为金标准,对间接ELISA法的特异性、敏感性和准确性进行验证。结果纯化的重组CFP10-PPE68融合蛋白纯度约为70%。分别以重组CFP10-PPE68、CFP10和PPE68蛋白作为包被抗原的最佳包被浓度分别为2、4、4μg/ml,血清最佳稀释度均为1∶1 000,酶标二抗最佳稀释度均为1∶5 000。3种蛋白对肺外结核的诊断效果均优于肺结核,且重组CFP10-PPE68融合蛋白检测肺外结核的特异性、敏感性及准确性均最佳;3种蛋白诊断结核病的特异性较高,而敏感性相对较低。结论以重组CFP10-PPE68融合蛋白作为包被抗原建立的间接ELISA法诊断MTB感染具有较高的敏感性和特异性,特别是对难以诊断的肺外结核病的诊断有一定的参考价值。  相似文献   
10.
本文就改性聚苯醚的国外市场动态,开发耐光性改性聚苯醚及其用途、性能和制法进行综述。提出开发聚苯醚的建议和看法。  相似文献   
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