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451.
Aromatic carboxylic acid self-assembly has been a hot research field for many scientists due to its strong coordination ability and flexible coordination mode.The hydrogen bond formed between aromatic carboxylic acids is a strong intermolecular force and has directionality and saturation,which plays a very important role in the self-assembly and regulation of aromatic carboxylic acids.In this review,we introduce surface organization formed by aromatic carboxylic acids with the aid of scanning tunneling microscopy(STM).These two-dimensional structures include molecular templates,host-guest systems,and photo-isomerization structures.We also emphasize the thermodynamics and dynamics,which are important research topics of current and future study. 相似文献
452.
为了能够实时成像和同步显示,设计了一种结构简单、携带方便的大面阵CMOS实时成像及显示系统,采用EPF10K50完成了MT9M413C36STM图像生成时序和SXGA显示时序及数据输出的多路转换设计.图像传感器的数据输出转换为两路,一路数据输出给处理电路进行图像实时处理;另一路经ADV7127视频数模变换后输出,可以连接SXGA形式的显示器同步显示图像.实验设计了相关硬件电路,并用VHDL语言编写了驱动程序,在Quartus 8.0的开发环境下,进行了调试.结果表明,该系统可以在1280×1024 @ 60Hz逐行扫描模式下稳定地工作. 相似文献
453.
D.A. Svintsitskiy A.I. Stadnichenko D.V. DemidovS.V. Koscheev A.I. Boronin 《Applied Surface Science》2011,257(20):8542-8549
Nanostructured copper (II) oxide was formed on clean copper foil at room temperature using activated oxygen produced by RF discharge. CuO particles of approximately 10-20 nm were observed on the surface by Scanning Tunneling Microscopy (STM). The copper states and oxygen species of the model cupric oxide were studied by means of X-ray Photoelectron Spectroscopy (XPS). These oxide particles demonstrated abnormally high reactivity with carbon monoxide (CO) at temperatures below 100 °C. The XPS data showed that the interaction of CO with the nanostructured cupric oxide resulted in reduction of the CuO particles to Cu2O species. The reactivity of the nanostructured cupric oxide to CO was studied at 80 °C using XPS in step-by-step mode. The initial reactivity was estimated to be 5 × 10−5 and was steadily reduced down to 5 × 10−9 as the exposure was increased. O1s spectral analysis allowed us to propose that the high initial reactivity was caused by the presence of non-lattice oxygen states on the surface of the nanostructured CuO. We established that reoxidation of the partially reduced nanostructured cupric oxide by molecular oxygen O2 restored the highly reactive oxygen form on the surface. These results allowed us to propose that the nanostructured cupric oxide could be used for low temperature catalytic CO oxidation. Some hypotheses concerning the nature of the non-lattice oxygen species with high reactivity are also discussed. 相似文献
454.
We report cryogenic scanning tunneling spectroscopy measurements on single crystals of superconducting FeSe1−xTex, at doping levels of x=0.5 and 0.7, with critical temperatures . Atomically resolved topographic images were obtained, showing large-scale density-of-state clustering which appears to have no periodicity and to vary with the doping. Conductance spectra taken at 300 mK showed a generally asymmetric V-shaped background, along with a sharp dip structure within . These spectra appeared to vary over ∼nm length scale, and not correlated with the topography. The overall spectral evolution versus temperature is consistent with the dip structure arising from a superconducting energy gap which closes above Tc, and with the spectral background having a non-superconducting origin. The persistence of finite zero-bias conductance down to 300 mK, well below Tc, indicates the presence of low-energy quasiparticles on parts of the Fermi surface. We discuss our data in light of some other recent spectroscopic measurements of FeSe1−xTex, and in terms of its characteristic band structure. 相似文献
455.
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457.
据报道每年中国丢失的儿童、老人、智障患者共有80多万,只有极少数可以被安全找回,再者当今社会经常出现老年人摔倒在地而无人搀扶的情况。为解决此类问题,本文设计了一款基于GPS/LBSS的人体定位监护系统。该系统以ARMSCortex-M3S系列的STM32F103ZE为核心处理器,结合GPS卫星定位模块、无线通信模块、三轴加速度计和三轴陀螺仪以及在VC++平台开发的GIS上位机构成监护系统。该监护系统可根据用户的需求实现实时定位、紧急求救、跌倒检测、电子围栏等功能。定位模式采用GPS/LBS双模式定位,提高定位精度;通信方式采取GSM/GPRS双通信模式,无通信盲区,数据传输稳定。 相似文献
458.
In this review,a group of two-dimensional(2D) hydrogen-bonded supramolecular networks developed in our laboratory are discussed.Our attention is mainly focused on:(1) recognition of Fe3+ through twocomponent molecular networks;(2) site-selective fabrication of 2D fullerene arrays;and(3) fabrication of the nanoporous structure regulated by photoisomerization reaction process.It is envisioned that special supramolecular nanostructures,through H-bonding interactions,can be constructed or reconstructed to be further investigated toward the research of multi-component systems,molecule recognition,single molecular switches,and host-guest supramolecular chemistry. 相似文献
459.
Junyu Zong 《中国物理 B》2022,31(10):107301-107301
As a special order of electronic correlation induced by spatial modulation, the charge density wave (CDW) phenomena in condensed matters attract enormous research interests. Here, using scanning—tunneling microscopy in various temperatures, we discover a hidden incommensurate stripe-like CDW order besides the ($sqrt{7}$ × $sqrt{3}$) CDW phase at low-temperature of 4 K in the epitaxial monolayer 1T-VSe2} film. Combining the variable-temperature angle-resolved photoemission spectroscopic (ARPES) measurements, we discover a two-step transition of an anisotropic CDW gap structure that consists of two parts Δ1 and Δ2. The gap part Δ1 that closes around ~ 150 K is accompanied with the vanish of the ($sqrt{7}$ × $sqrt{3}$) CDW phase. While another momentum-dependent gap part Δ2 can survive up to ~ 340 K, and is suggested to the result of the incommensurate CDW phase. This two-step transition with anisotropic gap opening and the resulted evolution in ARPES spectra are corroborated by our theoretical calculation based on a phenomenological form for the self-energy containing a two-gap structure Δ1 + Δ2, which suggests different forming mechanisms between the ($sqrt{7}$ × $sqrt{3}$) and the incommensurate CDW phases. Our findings provide significant information and deep understandings on the CDW phases in monolayer 1T-VSe2} film as a two-dimensional (2D) material. 相似文献
460.
Experimental observation of pseudogap in a modulation-doped Mott insulator: Sn/Si(111)-(√30×√30)R30°
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Yan-Ling Xiong 《中国物理 B》2022,31(6):67401-067401
Unusual quantum phenomena usually emerge upon doping Mott insulators. Using a molecular beam epitaxy system integrated with cryogenic scanning tunneling microscope, we investigate the electronic structure of a modulation-doped Mott insulator Sn/Si(111)-($\sqrt{3}\times \sqrt{3})R$30$^\circ$. In underdoped regions, we observe a universal pseudogap opening around the Fermi level, which changes little with the applied magnetic field and the occurrence of Sn vacancies. The pseudogap gets smeared out at elevated temperatures and alters in size with the spatial confinement of the Mott insulating phase. Our findings, along with the previously observed superconductivity at a higher doping level, are highly reminiscent of the electronic phase diagram in the doped copper oxide compounds. 相似文献