Abstract-Terahertz absorption characteristics of guar gum determined via microfluidic technology

 

Feng-Xuan Zhang, Guo-Yang Wang, Hai-Yun Huang, Meng-Han Chen, Si-Jia Zhang, Bo Su,  Cun-Lin Zhang 

https://jeos.springeropen.com/articles/10.1186/s41476-021-00162-x

The vibrational energy levels of many biomolecules correspond to the terahertz band; thus, terahertz technology can be used to identify these substances. Moreover, as the biological activity of most biomolecules can be observed only in aqueous solution, the characteristics of such biomolecules must be studied in aqueous solution. In this study, a simple microfluidic chip, a temperature control device and a strong electric field device were designed to study the terahertz absorption characteristics of guar gum for different temperatures, concentrations and electric field exposure durations, thus enabling the use of terahertz technology to analyse the characteristics of guar gum.

Abstract-Terahertz spectral analysis of different electrolytes

Yi-Wei Wen, Bo Su, Jia-Hui Wang, Guo-Yang Wang, Ya-Xiong Wu, Jing-Suo He, Cun-Lin Zhang,

 https://www.spiedigitallibrary.org/journals/Optical-Engineering/volume-59/issue-5/055107/Terahertz-spectral-analysis-of-different-electrolytes/10.1117/1.OE.59.5.055107.short

Terahertz (THz) technology has become popular worldwide as a new approach to detecting biomolecules because the vibrational and rotational energy levels of many biomolecules fall in the THz band and because the THz wave has the characteristics of low electronic energy, which will not damage the samples to be measured. Many biomolecules need to maintain their biological activity in liquid environment. However, as a polar molecule, water has a strong absorption of THz wave, which is mainly because the vibration frequency of hydrogen bond in aqueous solution is within the THz frequency range. Therefore, the best solution is to reduce the action distance between the aqueous solution and THz wave and control it within 100  μm. Microfluidic chips can meet such requirements. Therefore, the combination of THz technology and microfluidic technology can study the dynamic characteristics of biomolecules in an aqueous solution. The microfluidic chip was fabricated using ZEONOR 1420Rs. The THz transmittance of the material can exceed 95%. The depth of the microchannel in the microfluidic chip is 50  μm. In addition, the chip has the characteristics of good airtightness, portability, convenient disassembling, and reusability. Seventeen kinds of electrolytes were tested with the chip. The results show that the THz spectral intensity of electrolyte composed of different anions and cations, so the spectral characteristics of other electrolyte solutions can be obtained according to the spectral information of these detected ions.

© 2020 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2020/$28.00 © 2020 SPIE

Abstract-Strong Terahertz Radiation from a Liquid-Water Line

Liang-Liang Zhang, Wei-Min Wang, Tong Wu, Shi-Jia Feng, Kai Kang, Cun-Lin Zhang, Yan Zhang, Yu-Tong Li, Zheng-Ming Sheng, and Xi-Cheng Zhang

https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.12.014005

Terahertz radiation generation from liquid water has long been considered impossible due to strong absorption. A few very recent works reported terahertz generation from water, but the mechanism is not clear and the efficiency demands to be enhanced. We show experimentally that strong single-cycle terahertz radiation with field strength of $0.2\mathrm{MV}{\mathrm{cm}}^{-1}$ is generated from a water line (or column) of approximately $200\mu m$ in diameter irradiated by a mJ femtosecond laser beam. This strength is 100-fold higher than that produced from air using single-color pumping. We attribute the mechanism to the laser-ponderomotive-force-induced current with the symmetry broken around the water-column interface. This mechanism can explain our following observations: the radiation can be generated only when the laser propagation axis deviates from the column center; the deviation determines its field strength and polarity; it is always $p$ polarized no matter whether the laser is $p$ or $s$ polarized. This study provides a simple and efficient scheme of table-top terahertz sources based on liquid water.

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Abstract-Synthesis, structure, terahertz spectroscopy and luminescent properties of copper (I) complexes with bis(diphenylphosphino)methane and N-donor ligands

• Wei-Wei Fan^a, 
• Zhong-Feng Li^a, 
• Jiao-Bao Li^a, 
• Yu-Ping Yang^b, 
• Yuan Yuan^a, 
• Han-Qin Tang^a,
• Ling-Xiao Gao^a, 
• Qiong-Hua Jin^a, , , 
• Zhen-Wei Zhang^c, 
• Cun-Lin Zhang^c

• ^a Department of Chemistry, Capital Normal University, Beijing 100048, PR China
• ^b School of Science, Minzu University of China, Beijing 100081, PR China
• ^c Beijing Key Laboratory for Terahertz Spectroscopy and Imaging, Key Laboratory of Terahertz Optoelectronics, Ministry of Education, Department of Physics, Capital Normal University, Beijing 100048, PR China

http://www.sciencedirect.com/science/article/pii/S0022286015300909

The reactions of copper(I) salts CuX [X = Cl, OTf (OTf = CF₃SO₃) and ClO₄] and bis(diphenylphosphino)methane (dppm) with 4,4-bipyridine (4,4-bipy), 2,2-bipyridine (2,2-bipy), isoquinoline (i-C₉H₇N) and 1,10-phenanthroline (phen) lead to five new copper(I) complexes: [CuCl(dppm)(i-C₉H₇N)]₂ (1), {[CuCl(dppm)(phen)]₂•5H₂O}_n (2), [Cu₂Cl₂(dppm)₂(4,4-bipy)]•4CH₃CN (3), [Cu(dppm)(2,2-bipy)]₂(OTf)₂ (4), {[Cu₂Cl(dppm)₂(4,4-bipy)](ClO₄)}_n (5). Complexes 1, 3 and 4 are of dinuclear structure with eight-membered Cu₂P₄C₂ rings. The structure of compound 2 can be simplified as three-dimensional topology. Complex 5 is of infinite chain structure linked by 4,4-bipy. All these complexes are characterized by IR, elemental analyses, single-crystal X-ray diffraction analysis, luminescence, NMR and terahertz time-domain spectroscopy.