scholarly journals Large change of interlayer vibrational coupling with stacking in Mo1−xWxTe2

2022 ◽  
Vol 105 (1) ◽  
Author(s):  
John A. Schneeloch ◽  
Yu Tao ◽  
Jaime A. Fernandez-Baca ◽  
Guangyong Xu ◽  
Despina Louca
Keyword(s):  
Large Change ◽  
Vibrational Coupling

Infrared spectra and substituent effects in 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones

1983 ◽  
Vol 48 (2) ◽  
pp. 586-595 ◽  
Author(s):  
Alexander Perjéssy ◽  
Pavol Hrnčiar ◽  
Ján Šraga
Keyword(s):  
Substituent Effects ◽  
Phenyl Group ◽  
Wave Number ◽  
Vibrational Coupling ◽  
Wave Numbers ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The Relationship ◽  
Derivatives Of ◽  
Effect Of Structure

The wave numbers of the fundamental C=O and C=C stretching vibrations, as well as that of the first overtone of C=O stretching vibration of 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones and 1,3-cycloheptanedione were measured in tetrachloromethane and chloroform. The spectral data were correlated with σ+ constants of substituents attached to phenyl group and with wave number shifts of the C=O stretching vibration of substituted acetophenones. The slope of the linear dependence ν vs ν+ of the C=C stretching vibration of the ethylenic group was found to be more than two times higher than that of the analogous correlation of the C=O stretching vibration. Positive values of anharmonicity for asymmetric C=O stretching vibration can be considered as an evidence of the vibrational coupling in a cyclic 1,3-dicarbonyl system similarly, as with derivatives of 1,3-indanedione. The relationship between the wave numbers of the symmetric and asymmetric C=O stretching vibrations indicates that the effect of structure upon both vibrations is symmetric. The vibrational coupling in 1,3-cycloheptanediones and the application of Seth-Paul-Van-Duyse equation is discussed in relation to analogous results obtained for other cyclic 1,3-dicarbonyl compounds.

scholarly journals Tin Disulfide-Coated Microfiber for Humidity Sensing with Fast Response and High Sensitivity

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 648
Author(s):  
Aijie Liang ◽  
Jingyuan Ming ◽  
Wenguo Zhu ◽  
Heyuan Guan ◽  
Xinyang Han ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
Small Diameter ◽  
High Sensitivity ◽  
Large Change ◽  
Small Variation ◽  
Response Speed ◽  
Fast Response ◽  
Tin Disulfide ◽  
Recovery Times ◽  
Response And Recovery

Breath monitoring is significant in assessing human body conditions, such as cardiac and pulmonary symptoms. Optical fiber-based sensors have attracted much attention since they are immune to electromagnetic radiation, thus are safe for patients. Here, a microfiber (MF) humidity sensor is fabricated by coating tin disulfide (SnS2) nanosheets onto the surface of MF. The small diameter (~8 μm) and the long length (~5 mm) of the MF promise strong interaction between guiding light and SnS2. Thus, a small variation in the relative humidity (RH) will lead to a large change in optical transmitted power. A high RH sensitivity of 0.57 dB/%RH is therefore achieved. The response and recovery times are estimated to be 0.08 and 0.28 s, respectively. The high sensitivity and fast response speed enable our SnS2-MF sensor to monitor human breath in real time.

scholarly journals Challenges for Change Agents. Best Practices at the University Library of Freie Universität Berlin

ABI-Technik ◽  
2020 ◽  
Vol 40 (4) ◽  
pp. 357-364
Author(s):  
Martin Lee ◽  
Christina Riesenweber
Keyword(s):  
Best Practices ◽  
Change Agents ◽  
Large Change ◽  
University Library ◽  
The Future ◽  
The University ◽  
Insight Into

AbstractThe authors of this article have been managing a large change project at the university library of Freie Universität Berlin since January 2019. At the time of writing this in the summer of 2020, the project is about halfway completed. With this text, we would like to give some insight into our work and the challenges we faced, thereby starting conversations with similar undertakings in the future.

scholarly journals Water Erosion Risk Assessment in the Kenya Great Rift Valley Region

2021 ◽  
Vol 13 (2) ◽  
pp. 844
Author(s):  
George Watene ◽  
Lijun Yu ◽  
Yueping Nie ◽  
Jianfeng Zhu ◽  
Thomas Ngigi ◽  
...  
Keyword(s):  
Rift Valley ◽  
Soil Loss ◽  
Large Change ◽  
Risk Category ◽  
Lake Nakuru ◽  
Erosion Risk ◽  
Erosion Rates ◽  
3.0 T ◽  
Great Rift Valley ◽  
Loss Rates

The Kenya Great Rift Valley (KGRV) region unique landscape comprises of mountainous terrain, large valley-floor lakes, and agricultural lands bordered by extensive Arid and Semi-Arid Lands (ASALs). The East Africa (EA) region has received high amounts of rainfall in the recent past as evidenced by the rising lake levels in the GRV lakes. In Kenya, few studies have quantified soil loss at national scales and erosion rates information on these GRV lakes’ regional basins within the ASALs is lacking. This study used the Revised Universal Soil Loss Equation (RUSLE) model to estimate soil erosion rates between 1990 and 2015 in the Great Rift Valley region of Kenya which is approximately 84.5% ASAL. The mean erosion rates for both periods was estimated to be tolerable (6.26 t ha−1 yr−1 and 7.14 t ha−1 yr−1 in 1990 and 2015 respectively) resulting in total soil loss of 116 Mt yr−1 and 132 Mt yr−1 in 1990 and 2015 respectively. Approximately 83% and 81% of the erosive lands in KGRV fell under the low risk category (<10 t ha−1 yr−1) in 1990 and 2015 respectively while about 10% were classified under the top three conservation priority levels in 2015. Lake Nakuru basin had the highest erosion rate net change (4.19 t ha−1 yr−1) among the GRV lake basins with Lake Bogoria-Baringo recording annual soil loss rates >10 t ha−1 yr−1 in both years. The mountainous central parts of the KGRV with Andosol/Nitisols soils and high rainfall experienced a large change of land uses to croplands thus had highest soil loss net change (4.34 t ha−1 yr−1). In both years, forests recorded the lowest annual soil loss rates (<3.0 t ha−1 yr−1) while most of the ASAL districts presented erosion rates (<8 t ha−1 yr−1). Only 34% of all the protected areas were found to have erosion rates <10 t ha−1 yr−1 highlighting the need for effective anti-erosive measures.

Heterionic vibrational coupling in crystalline methylammonium nitrate

1992 ◽  
Vol 88 (12) ◽  
pp. 1631 ◽  
Author(s):  
Upali A. Jayasooriya ◽  
Sidney F. A. Kettle ◽  
Richard Mortimer ◽  
Juergen Eckert ◽  
Nancy K. McGuire
Keyword(s):  
Vibrational Coupling

scholarly journals An electron transfer driven magnetic switch: ferromagnetic exchange and spin delocalization in iron verdazyl complexes

2018 ◽  
Vol 47 (18) ◽  
pp. 6351-6360 ◽  
Author(s):  
David J. R. Brook ◽  
Connor Fleming ◽  
Dorothy Chung ◽  
Cardius Richardson ◽  
Servando Ponce ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Spin Crossover ◽  
Large Change ◽  
Single Electron ◽  
Spin Multiplicity ◽  
Magnetic Switch ◽  
Ferromagnetic Exchange ◽  
Spin Delocalization ◽  
Electron Reduction

A single electron reduction of an iron bis(verdazyl) complex results in a large change in spin multiplicity resulting from a combination of spin crossover and exceptionally strong ferromagnetic exchange.

Effect of Interface and Crystallinity on the Ferroelectric Properties of Poly(Vinylidene Fluoride-Trifluoroethylene) Copolymer Thin Films

2001 ◽  
Vol 665 ◽  
Author(s):  
Feng Xia ◽  
H.S. Xu ◽  
Babak Razavi ◽  
Q. M. Zhang
Keyword(s):  
Thin Films ◽  
Vinylidene Fluoride ◽  
Ferroelectric Properties ◽  
Large Change ◽  
Thickness Dependence ◽  
Dielectric Measurement ◽  
Switching Speed ◽  
Wide Range ◽  
Poly Vinylidene Fluoride ◽  
Polarization Level

ABSTRACTFerroelectric polymer thin films are attractive for a wide range of applications such as MEMS, IR sensors, and memory devices. We present the results of a recent investigation on the thickness dependence of the ferroelectric properties of poly(vinylidene fluoridetrifluoroethylene) copolymer spin cast films on electroded Si substrate. We show that as the film thickness is reduced, there exist two thickness regions. For films at thickness above 100 nm, the thickness dependence of the ferroelectric properties can be attributed to the interface effect. However, for thinner films, there is a large change in the ferroelectric properties such as the polarization level, the coercive field, and polarization switching speed, which is related to the large drop of the crystallinity in the ultrathin film region (below 100 nm). The results from Xray, dielectric measurement, and AFM all indicate that there is a threshold thickness at about 100 nm below which the crystallinity in the film reduces abruptly.

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