Refraction of Flexural Waves by Ultra-broadband Achromatic Meta-slab with Wavelength-dependent Phase Shifts

2021 ◽  
pp. 1-22
Author(s):  
Feng Liu ◽  
Zhi-chun Yang ◽  
Pengtao Shi ◽  
Yizhou Shen ◽  
Liyun Cao ◽  
...  
Keyword(s):  
Vibrational Energy ◽  
Chromatic Aberration ◽  
Phase Shifts ◽  
Refraction Angle ◽  
Flexural Waves ◽  
Compensation Principle ◽  
Narrow Bandwidth ◽  
Great Progress ◽  
Vibrational Energy Harvesting ◽  
Made In

Abstract Great progress has been made in modulating flexural waves by elastic metasurfaces. Most of the proposed elastic metasurfaces suffer from chromatic aberration, limited in a narrow bandwidth around the designed frequency. In this paper, overcoming the chromatic aberration, an ultra-broadband achromatic meta-slab (UAM) with subunits of gradient thickness is proposed to realize the refraction angle unchanged with the incident frequency. Based on the phase compensation principle, wavelength-dependent phase shifts for the UAM that realize achromaticity are obtained. In order to verify the effectiveness of the theoretical design, the transmitted wavefields are solved according to the phased array theory, and the results correspond with those obtained by the finite element (FE) simulations and experiments, which show that the refraction angle is unchanged for incident frequencies from 2 kHz to 8 kHz. Besides, the UAM is extended into a periodic meta-slab, and multifrequency achromaticity is realized. Our designed meta-slabs overcome the chromatic aberration by simple configurations, which have significance in the applications of vibration control, vibrational energy harvesting, and health monitoring.

Vibrational Energy Harvesting Devices

2010 ◽  
Vol 2 (2) ◽  
pp. 80-92
Author(s):  
Rupesh Patel ◽  
Atanas A. Popov ◽  
Stewart McWilliam
Keyword(s):  
Energy Harvesting ◽  
Vibrational Energy ◽  
Energy Harvesting Devices ◽  
Vibrational Energy Harvesting

scholarly journals Pathogenesis and Potential Therapeutic Targets for Triple-Negative Breast Cancer

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2978
Author(s):  
Chia-Jung Li ◽  
Yen-Dun Tony Tzeng ◽  
Yi-Han Chiu ◽  
Hung-Yu Lin ◽  
Ming-Feng Hou ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Targeted Therapy ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
High Efficiency ◽  
Early Recurrence ◽  
New Developments ◽  
Great Progress ◽  
Low Toxicity ◽  
Made In

Triple negative breast cancer (TNBC) is a heterogeneous tumor characterized by early recurrence, high invasion, and poor prognosis. Currently, its treatment includes chemotherapy, which shows a suboptimal efficacy. However, with the increasing studies on TNBC subtypes and tumor molecular biology, great progress has been made in targeted therapy for TNBC. The new developments in the treatment of breast cancer include targeted therapy, which has the advantages of accurate positioning, high efficiency, and low toxicity, as compared to surgery, radiotherapy, and chemotherapy. Given its importance as cancer treatment, we review the latest research on the subtypes of TNBC and relevant targeted therapies.

Rhodium-Catalyzed, Phosphorus(III)-Directed Hydroarylation of Internal Alkynes: Facile and Efficient Access to New Phosphine Ligands

Synlett ◽  
2020 ◽  
Author(s):  
Minyan Wang ◽  
Zhuangzhi Shi ◽  
Huanhuan Luo ◽  
Dawei Wang
Keyword(s):  
High Selectivity ◽  
Enantiomeric Excess ◽  
Phosphine Ligands ◽  
Rapid Construction ◽  
Efficient Access ◽  
Internal Alkynes ◽  
Great Progress ◽  
Chiral Phosphine Ligands ◽  
Optimized Conditions ◽  
Made In

AbstractOrganophosphines are an important class of ligands widely used in organic chemistry. Although great progress has recently been made in the rapid construction of new phosphines through Rh- or Ru-catalyzed C–H bond functionalizations, synthetic access to more diverse phosphines remains a challenge. We describe an efficient process for the rhodium-catalyzed phosphorus(III)-directed hydroarylation of internal alkynes to generate various alkenylated and 2′,6′-dialkenylated biarylphosphines with high selectivity. A range of diverse alkynes and phosphines were effectively prepared with broad functional-group compatibility under the optimized conditions. In addition, the developed protocol can be extended to modify chiral phosphine ligands, providing enantioenriched alkenylated phosphines without erosion of the enantiomeric excess.

An analytic study of vibrational energy harvesting using piezoelectric tiles in stairways subjected to human traffic

2018 ◽  
Vol 30 (5) ◽  
pp. 968-985
Author(s):  
CONNOR EDLUND ◽  
SUBRAMANIAN RAMAKRISHNAN
Keyword(s):  
Energy Harvesting ◽  
Vibrational Energy ◽  
Electrical Power ◽  
Random Excitation ◽  
Analytical Models ◽  
Practical Applications ◽  
Type Iii ◽  
Pedestrian Traffic ◽  
Type V ◽  
Vibrational Energy Harvesting

This work investigates analytically, the use of piezoelectric tiles placed on stairways for vibrational energy harvesting – harnessing electrical power from natural vibrational phenomena – from pedestrian footfalls. While energy harvesting from pedestrian traffic along flat pathways has been studied in the linear regime and realised in practical applications, the greater amounts of energy naturally expended in traversing stairways suggest better prospects for harvesting. Considering the characteristics of two types of commercially available piezoelectric tiles – Navy Type III and Navy Type V – analytical models for the coupled electromechanical system are formulated. The harvesting potential of the tiles is then studied under conditions of both deterministic and carefully developed random excitation profiles for three distinct cases: linear, monostable nonlinear and an array of monostable nonlinear tiles on adjacent steps with linear coupling between them. The results indicate enhanced power output when the tiles are: (1) placed on stairways, (2) uncoupled and (3) subjected to excitation profiles with stochastic frequency. In addition, the Navy Type V tiles are seen to outperform the Navy Type III tiles. Finally, the strongly nonlinear regime outperforms the linear one suggesting that the realisation of commercially available piezoelectric tiles with appropriately tailored nonlinear characteristics will likely have a significant impact on energy harvesting from pedestrian traffic.

A HIGHLY ACCURATE ULTRASONIC MEASUREMENT SYSTEM FOR TREMOR USING BINARY AMPLITUDE-SHIFT-KEYING AND PHASE-SHIFT METHOD

2003 ◽  
Vol 15 (02) ◽  
pp. 61-67 ◽  
Author(s):  
MENG-HSIANG YANG ◽  
K. N. HUANG ◽  
C. F. HUANG ◽  
S. S. HUANG ◽  
M. S. YOUNG
Keyword(s):  
Phase Shift ◽  
Measurement System ◽  
Low Cost ◽  
Phase Shifts ◽  
Ultrasonic Waves ◽  
Shift Method ◽  
Narrow Bandwidth ◽  
Shift Keying ◽  
Modulation Signal ◽  
Phase Shift Method

A highly accurate Binary Amplitude-Shift-Keyed (BASK) ultrasonic tremor measurement system for use in isothermal air is developed. In this paper, we present a simple but efficient algorithm based upon phase shifts generated by three ultrasonic waves of different frequencies. By the proposed method, we can conduct larger range measurement than the phase-shift method and also get higher accuracy compared with the time-of-flight (TOF) method. Our microcomputer-based system includes two important parts. One of which is BASK modulation signal generator. The other is a phase meter designed to record and compute the phase shifts of the three different frequencies and the result motion is then sent to either an LCD for display or a PC for calibration. Experiments are done in the laboratory using BASK modulation for the frequencies of 200 Hz and 1 kHz with a 40 kHz carrier. The measurement accuracy of this measurement system in the reported experiments is within +/- 0.98 mm. The main advantages of this ultrasonic tremor measurement system are high resolution, narrow bandwidth requirement, low cost, and easy to be implemented.

ScAlN MEMS Cantilevers for Vibrational Energy Harvesting Purposes

2017 ◽  
Vol 26 (1) ◽  
pp. 102-112 ◽  
Author(s):  
P. M. Mayrhofer ◽  
C. Rehlendt ◽  
M. Fischeneder ◽  
M. Kucera ◽  
E. Wistrela ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Vibrational Energy ◽  
Mems Cantilevers ◽  
Vibrational Energy Harvesting

Accountability in an Era of Celebrity

2019 ◽  
pp. 150-174
Author(s):  
Martha C. Nussbaum
Keyword(s):  
Social Norms ◽  
Sexual Violence ◽  
Working Women ◽  
Historical Evolution ◽  
The Public ◽  
Great Progress ◽  
The Law ◽  
Made In

While great progress has been made in regards to sexual violence and accountability, Martha C. Nussbaum argues that the culture of celebrity remains a significant hurdle. In this chapter, Nussbaum traces the historical evolution and progress of the law and social norms concerning sexual violence. Identifying the obstacles and complexities that have faced those fighting for justice, she shows how working women, feminist lawyers, and recently the #MeToo movement have pushed forward the frontier of accountability. While history provides reason for hope, a recalcitrant problem remains: lack of accountability for celebrities and sports stars. Given the big money and structures of power behind the culture of celebrity, Nussbaum argues that the public must rise up and express outrage in order to bring about change.

scholarly journals Atomic Physics of the 12-μm and Related Lines

1994 ◽  
Vol 154 ◽  
pp. 297-307
Author(s):  
Edward S. Chang
Keyword(s):  
Atomic Physics ◽  
Stark Effect ◽  
Disk Center ◽  
Emission Peak ◽  
Emission Lines ◽  
Line Profiles ◽  
Great Progress ◽  
Quadratic Stark Effect ◽  
Rydberg Transitions ◽  
Made In

The 12 μm emission lines were unexpectedly detected about a decade ago. Great progress has been made in understanding the atomic physics underlying these high-l Rydberg transitions in Mg I and other atoms. In a magnetic field, their Landé g factor is shown to be unity. At disk center, the shift of the absorption trough relative to the emission peak is demonstrated to be due to the quadratic Stark Effect, permitting measurement of the photospheric electric field strengths. Other related lines of Mg I require accurate atomic fine structure data to interpret properly their complex line profiles. Related lines are found in the ATMOS spectra for C I, Na I, Al I, Si I, Ca I, and Fe I, in addition to H I.

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