scholarly journals Large temperature tuning of the emission color of a phosphor by dual use of Raman and photoluminescence signals

2020 ◽  
Vol 7 (4) ◽  
pp. 1101-1105
Author(s):  
Arnab De ◽  
Rajeev Ranjan
Keyword(s):  
High Performance ◽  
Large Temperature ◽  
Dual Use ◽  
Emission Color ◽  
Temperature Tuning

High performance optical thermomertry by combining Raman and photoluminescence signals from phosphor materials.

Compact Cooling Devices Based on Giant Electrocaloric Effect Dielectrics

2012 ◽  
Author(s):  
Haiming Gu ◽  
Xinyu Li ◽  
S. G. Lu ◽  
Minren Lin ◽  
Xiaoshi Qian ◽  
...  
Keyword(s):  
High Performance ◽  
Dielectric Material ◽  
Coefficient Of Performance ◽  
Large Temperature ◽  
Cooling Power ◽  
Electrocaloric Effect ◽  
Temperature Range ◽  
Cooling Devices ◽  
Volume Method ◽  
Two Sides

The electrocaloric effect (ECE) refers to the change in temperature and/or entropy of a dielectric material due to the electric field induced change of dipolar states. Giant ECE is discovered in P(VDF-TrFE) ferroelectric copolymers near ferroelectric-paraelectric (F-P) transition temperature which is normally much higher than room temperature. This paper presents the two defect-inducing methods to lower and broaden working temperature range of P(VDF-TrFE) based copolymers for ECE, and thus make it preferable for practical cooling device. Giant ECE is experimentally demonstrated in large temperature range (0–55°C). In addition, an electrocaloric oscillatory refrigerator (ECOR) was proposed and simulated by finite volume method and its high performance was theoretically demonstrated. Temperature gradient larger than 30 °C can be maintained across the two sides of a 1 cm device. For ΔT = 20 °C cooling condition, a high cooling power (5.4 W/cm2) and significantly higher coefficient of performance (COP) can be achieved (50% of Carnot efficiency).

High-Performance Emission/Color Dual-Switchable Polymer-Bearing Pendant Tetraphenylethylene (TPE) and Triphenylamine (TPA) Moieties

2019 ◽  
Vol 52 (14) ◽  
pp. 5131-5139 ◽  
Author(s):  
Ningwei Sun ◽  
Kaixin Su ◽  
Ziwei Zhou ◽  
Xuzhou Tian ◽  
Zhao Jianhua ◽  
...  
Keyword(s):  
High Performance ◽  
Emission Color ◽  
Polymer Bearing

Development of Thermoelectric Cooling Devices with Graded Structure

2005 ◽  
Vol 492-493 ◽  
pp. 151-156 ◽  
Author(s):  
Hitoshi Kohri ◽  
Ichiro Shiota
Keyword(s):  
Bismuth Telluride ◽  
Thermoelectric Materials ◽  
High Performance ◽  
Temperature Drop ◽  
Maximum Temperature ◽  
Large Temperature ◽  
Thermoelectric Cooling ◽  
Temperature Range ◽  
Graded Structure ◽  
Cooling Devices

Every thermoelectric material shows high performance at a specific narrow temperature range. The temperature range with high performance can be expanded by joining the materials with different peak temperature. This is the concept of a functionally graded material (FGM) for thermoelectric materials. Bismuth telluride is the best material for cooling devices at around room temperature. Then we investigated the thermoelectric cooling properties for bismuth telluride with two step graded structure. FGM samples were fabricated by three methods. The first FGM was synthesized by in situ method. The second one was fabricated by joining in a hot-press equipment. The last one was composed by joining with solder. Thermoelectric cooling properties were evaluated by observing the maximum temperature drop to electric current when the high temperature side was kept constant. The large temperature difference was obtained when the proper configuration of thermoelectric materials along the temperature gradient were performed. The coincidence of optimum electrical currents of composing materials is also essential to obtain the high cooling performance.

Overview of FGM Research in Japan

MRS Bulletin ◽  
1995 ◽  
Vol 20 (1) ◽  
pp. 19-21 ◽  
Author(s):  
M. Koizumi ◽  
M. Niino
Keyword(s):  
Thermal Stress ◽  
High Performance ◽  
Large Temperature ◽  
Functionally Gradient Materials ◽  
Optimum Distribution ◽  
Gradient Materials ◽  
Heat Resistant ◽  
Functionally Gradient ◽  
Composition Structure ◽  
Two Phases

Space planes require high-performance heat-resistant materials which can withstand ultrahigh temperatures and extremely large temperature gradients. To meet these needs, functionally gradient materials (FGMs) were proposed about 10 years ago in Japan.Figure 1 shows a conceptual diagram of functionally gradient materials, taking into account the relaxation of thermal stress. For the surface that contacts high-temperature gases at thousands of degrees, ceramics are used to provide adequate heat resistance. For the surface that provides cooling, metallic materials are used to furnish the necessary thermal conductivity and mechanical strength. In addition, the composition of these materials is formulated to provide optimum distribution of composition, structure, and porosity to effectively relax thermal stress.Since fiscal 1987, an R&D project entitled “Research on Fundamental Techniques to Develop Functionally Gradient Materials for Relaxation of Thermal Stress,” which aimed to develop ultra heat-resistant materials, had been carried out with special coordination funds from the Science and Technology Agency. The five-year project had two phases; Phase I was carried out from 1987 to 1989, and Phase II from 1990 to 1991.

scholarly journals Photonic RF and microwave channelizer based on a Kerr soliton crystal micro-comb

2020 ◽  
Author(s):  
David Moss
Keyword(s):  
Signal Processing ◽  
Signal Detection ◽  
High Performance ◽  
Ring Resonator ◽  
Low Complexity ◽  
Analog Signal ◽  
Major Advance ◽  
Fully Integrated ◽  
High Q ◽  
Temperature Tuning

We report a 92 channel RF channelizer based on a 48.9 GHz integrated micro-comb that operates via soliton crystals, together with a passive high-Q ring resonator that acts as a periodic filter with an optical 3dB bandwidth of 121.4 MHz. We obtain an instant RF bandwidth of 8.08 GHz and 17.55 GHz achieved through temperature tuning. These results represent a major advance to achieving fully integrated photonic RF spectrum channelizers with reduced low complexity, size, and high performance for digital-compatible signal detection and broadband analog signal processing.

Quality Training and Research around the Machine Tools

2013 ◽  
Vol 759 ◽  
pp. 55-62
Author(s):  
A. Rodríguez ◽  
I. Tabernero ◽  
S. Martínez ◽  
Aitzol Lamikiz
Keyword(s):  
Machine Tools ◽  
High Performance ◽  
Milling Machine ◽  
Dual Use ◽  
New Students ◽  
Training And Research ◽  
High Level ◽  
Five Axis ◽  
Support Research

The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high. The High Performance Manufacturing Group of the Faculty of Engineering of Bilbao has a workshop fully-equipped. In this way, these machine tools are valid both to support research carried out by the Group and also to improve teaching lessons, both theoretically and practically. In this paper, the case of a five-axis milling machine was presented and analyzed. Each year, the new students are taught to design various systems of the machine and they are also encouraged to make some practical tests. This dual use of machines is very useful since it allows to carry out high level researches, as well as to train new students in theoretical and practical issues.

Study of Frost Resistance of 50 Years Concrete Exposed to Saline Areas

2013 ◽  
Vol 275-277 ◽  
pp. 1341-1346
Author(s):  
De Cheng Zhang ◽  
Yan Ping Lv ◽  
Zheng Mao Ye
Keyword(s):  
Frost Resistance ◽  
High Performance ◽  
Large Temperature ◽  
Freezing And Thawing ◽  
The North ◽  
Single Side ◽  
Concrete Mechanical Properties ◽  
Saline Area ◽  
Design Requirements ◽  
Freezing And Thawing Cycles

The Hong Run petrochemical oil depot is located in a saline area in the north of Weifang.This area is severe cold in winter and has large temperature span throughout a year. Due to the area's rigorous environmental conditions, concrete with 50 years durability and strength grade of C40 was fabricated with the ordinary Portland cement, high performance superfine mineral powder and high performance pumping agent. Tests using the onsite concrete samples show that concrete mechanical properties meet the design requirements. After 300 freezing and thawing cycles including accelerated freezing thawing method and single-side freezing thawing method, the quality loss rate and relative dynamic modulus both comply with the design requirements. This suggests that the sample concrete has excellent frost resistance ability.

Photonic RF and microwave channelizer based on a Kerr soliton crystal micro-comb

2020 ◽  
Author(s):  
David Moss
Keyword(s):  
Signal Processing ◽  
Signal Detection ◽  
High Performance ◽  
Ring Resonator ◽  
Low Complexity ◽  
Analog Signal ◽  
Major Advance ◽  
Fully Integrated ◽  
High Q ◽  
Temperature Tuning

We report a 92 channel RF channelizer based on a 48.9 GHz integrated micro-comb that operates via soliton crystals, together with a passive high-Q ring resonator that acts as a periodic filter with an optical 3dB bandwidth of 121.4 MHz. We obtain an instant RF bandwidth of 8.08 GHz and 17.55 GHz achieved through temperature tuning. These results represent a major advance to achieving fully integrated photonic RF spectrum channelizers with reduced low complexity, size, and high performance for digital-compatible signal detection and broadband analog signal processing.

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