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1.
高端芯片制造所需要的极紫外光刻技术位于我国当前面临35项"卡脖子"关键核心技术之首.高转换效率的极紫外光源是极紫外光刻系统的重要组成部分.本文通过采用双激光脉冲打靶技术实现较强的6.7 nm极紫外光输出.首先,理论计算Gd18+—Gd27+离子最外层4d壳层的4p-4d和4d-4f能级之间跃迁、以及Gd14+—Gd17+离子最外层4f壳层的4d-4f能级之间跃迁对波长为6.7 nm附近极紫外光的贡献.其后开展实验研究,结果表明,随着双脉冲之间延时的逐渐增加,波长为6.7 nm附近的极紫外光辐射强度呈现先减弱、后增加、之后再减弱的变化趋势,在双脉冲延时为100 ns处产生的极紫外光辐射最强.并且,在延时为100 ns处产生的光谱效率最高,相比于单脉冲激光产生的光谱效率提升了33%.此外,发现双激光脉冲打靶技术可以有效地减弱等离子体的自吸收效应,获得的6.7 nm附近极紫外光谱宽度均小于单激光脉冲打靶的情形,且在脉冲延时为30 ns时刻所产生的光谱宽度最窄,约为单独主脉冲产生极紫外光谱宽度的1/3.同时... 相似文献
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A CE instrument that can be assembled from commercially available components with minimal construction effort is described. Except for the electronic control circuitry no specially made parts are required. It is based on a flexible design of microfluidic, electropneumatic, and electronic sections and different configurations can easily be implemented. Automated injection into the capillary is performed hydrodynamically by the application of a pressure for a controlled length of time. The performance of the device was tested with a contactless conductivity detector by separating different metal ions. In addition, nine metal cations related to the quality of honey were separated in 2.3 min and four honey samples were analysed quantitatively to demonstrate the applicability of the method. 相似文献
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随着全球资源的减少和环境的恶化,节能减排已成为人们关注的焦点,具有保温隔热功能的低辐射玻璃成为研究的热点。提高玻璃保温隔热性能最有效的方法就是在其表面涂覆低辐射率层。原材料丰富、导电性能好、可见光透过率高等优势使得Al掺杂ZnO (AZO)薄膜成为最具潜力的低辐射率层。系统研究了温度对AZO薄膜红外辐射性能的影响,分析了变化机理。首先研究了在一定的温度下持续一段时间后,AZO薄膜的红外比辐射率的变化情况。然后研究了在变温环境中红外比辐射率的变化情况。采用直流磁控溅射法在室温下玻璃基片上沉积500 nm厚的AZO薄膜,将薄膜放到马弗炉中进行热处理,在100~400 ℃空气气氛下保温1 h,随炉冷却。采用X射线衍射仪对AZO薄膜进行物相分析,采用扫描电子显微镜观察薄膜表面形貌变化。利用四探针测试法测量AZO薄膜的电阻率,采用红外比辐射率测试仪测试薄膜红外比辐射率, 可见分光光度计测量可见光谱。测试的结果表明,薄膜热处理前后均为六角纤锌矿结构,(002)择优取向。300 ℃及以下热处理1 h后,(002)衍射峰增强,半高宽变窄,晶粒尺寸长大。随着热处理温度的升高,薄膜的电阻率先减小后增大,200 ℃热处理后的薄膜具有最小的电阻率(0.9×10-3 Ω·cm)。热处理温度升高,晶粒长大使得薄膜电阻率降低。热处理温度过高,薄膜会从空气中吸收氧,电阻率下降。薄膜的红外比辐射率变化趋势和电阻率的一致,在200 ℃热处理后获得最小值(0.48)。自由电子对红外光子有较强的反射作用,当电阻率低,自由电子浓度高的时候,更多的红外光子被反射,红外辐射作用弱,红外比辐射率小。薄膜的可见光透过率随着热处理温度的升高先减小后增大,200 ℃热处理后的薄膜的可见光透过率最小,但仍高达82%。这种变化是由于自由电子浓度变化引起的,自由电子对可见光有很强的反射作用。选取未热处理和200 ℃热处理后的样品进行变温红外比辐射率的测量,将样品放在可加热的样品台上,位置固定,在室温到350 ℃的升温和降温过程中每隔25 ℃测量一次红外比辐射率,结果表明,在室温到350 ℃的温度范围内,AZO薄膜的红外比辐射率在升温过程中随着温度的上升而增大,在降温过程中减小,经过整个升、降温过程后,薄膜的红外比辐射率增大。 相似文献
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Laxmi Narayan Tripathi Sourabh Barua 《Progress in Crystal Growth and Characterization of Materials》2019,65(4):100465
This review article covers the growth and characterization of two-dimensional (2D) crystals of transition metal chalcogenides, h-BN, graphene, etc. The chemical vapor transport method for bulk single crystal growth is discussed in detail. Top-down methods like mechanical and liquid exfoliation and bottom-up methods like chemical vapor deposition and molecular beam epitaxy for mono/few-layer growth are described. The optimal characterization techniques such as optical, atomic force, scanning electron, and Raman spectroscopy for identification of mono/few-layer(s) of the 2D crystals are discussed. In addition, a survey was done for the application of 2D crystals for both creation and deterministic transfer of single-photon sources and photovoltaic systems. Finally, the application of plasmonic nanoantenna was proposed for enhanced solar-to-electrical energy conversion and faster/brighter quantum communication devices. 相似文献
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Synthesis and Characteristics of Organic Red‐Emissive Materials Based on Phenanthro[9,10‐d]imidazole
Red emission is one of the three primary colors that are essential for the realization of full‐color displays and solid‐state lightings. A high solid‐state efficiency is a crucial factor for the applications in organic light‐emitting diodes (OLEDs). In this work, two new donor‐acceptor‐donor type phenanthro[9,10‐d]imidazole (PIM)‐based derivatives, (2Z,2′Z)‐2,2′‐(1,4‐phenylene)bis(3‐(4‐(1‐phenyl‐1H‐phenanthro[9,10‐d]imidazol‐2‐yl)phenyl)acrylonitrile) ( PIDSB ) and 2,3‐bis(4′‐(1‐phenyl‐1H‐phenanthro[9,10‐d]imidazol‐2‐yl)‐[1,1′‐biphenyl]‐4‐yl)fumaronitrile ( PIDPh ), are designed and synthesized. Both of them possess high thermal stabilities. PIDPh shows typical characteristics of aggregation‐induced emission enhancement, while PIDSB displays an aggregation‐caused quenching effect. They both exhibit significant red‐shifted emissions compared with PIM owing to intramolecular charge transfer. In the film state, the emission peaks of PIDSB and PIDPh are located at 538 nm and 605 nm with high photoluminescent quantum yields of 63.82 % and 41.26 %, respectively. The non‐doped OLED using PIDPh as the active layer shows the maximum external quantum efficiency of 2.06 % with a very low efficiency roll‐off, and exhibits the electroluminescent peak at 640 nm with a Commission Internationale de l′Éclairage coordinate of (0.617,0.396), meeting well the criteria of red OLEDs. 相似文献
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A EuIII-containing single molecule BCR-Eu as design platform for ratio-metric fluorescent sensor which includes a blue-emitting coumarin dye, a green-emitting BODIPY fluorophore and a EuIII moiety as the origin of red light has been designed and synthesized. The compound BCR shows only green emission with large stoke shift when excited in 400 nm due to good fluorescence resonance energy transfer from coumarin to BODIPY. After embedding EuIII complexes in the molecule, BCR-Eu exhibits dual emission which is equal in magnitude and independent of each other, when excited at the range of 305–365 nm. An emission from Lanthanide complexes as the stable built-in standard fluorescence peak offers a promising opportunity to enhance the precision of bioimaging and also an ideal design platform for future ratio-metric fluorescent sensor. 相似文献
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2-Isopropylbenzimidazole and 2-methylbenzimidazole have been found to be effective bulky proton sources for stereoselective protonation of chiral enolate anions. 2-Isopropylbenzimidazole worked in the stereoselective protonation of the Birch reduction of chiral α,β-unsaturated imides. On the other hand, 2-methylbenzimidazole was found to be the best protonation reagent in the isomerization reaction of α,β-unsaturated imide into β,γ-unsaturated imide. The Birch reduction using 2-isopropylbenzimidazole realized a concise and stereoselective synthesis of δ-lactone 14, a sex pheromone of Macrocentrus grandii, while the isomerization reaction using 2-methylbenzimidazole was employed in the highly stereoselective synthesis of the γ-lactone intermediate in the synthesis of depsipeptide antibiotics. These bulky proton sources would be powerful tools to achieve a concise synthesis of natural products. 相似文献
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Furofuran lignans containing the 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane skeleton, represent one of the major subclasses of the lignan family of natural products. Furofuran lignans feature a wide variety of structures due to different substituents at aryl groups and diverse configurations at furofuran ring. Moreover, they exhibit a wide range of significant biological activities, including antioxidant, anti-inflammatory, cytotoxic, and antimicrobial activities. This review summarizes source, phytochemistry, and biological activities of 137 natural furofuran lignans isolated from 53 species in 41 genera of 27 plant families for the last 20 years, which provides a comprehensive information for further research of these furofuran lignans as potential pharmaceutical agents. 相似文献