scholarly journals In situ stiffness manipulation using elegant curved origami

2020 ◽  
Vol 6 (47) ◽  
pp. eabe2000
Author(s):  
Zirui Zhai ◽  
Yong Wang ◽  
Ken Lin ◽  
Lingling Wu ◽  
Hanqing Jiang
Keyword(s):  
High Power ◽  
High Efficiency ◽  
Negative Stiffness ◽  
Positive Zero ◽  
Uniform Load ◽  
Saving Energy ◽  
Space Saving ◽  
Force Transmissibility ◽  
New Applications

The capability of stiffness manipulation for materials and structures is essential for tuning motion, saving energy, and delivering high power. However, high-efficiency in situ stiffness manipulation has not yet been successfully achieved despite many studies from different perspectives. Here, curved origami patterns were designed to accomplish in situ stiffness manipulation covering positive, zero, and negative stiffness by activating predefined creases on one curved origami pattern. This elegant design enables in situ stiffness switching in lightweight and space-saving applications, as demonstrated through three robotic-related components. Under a uniform load, the curved origami can provide universal gripping, controlled force transmissibility, and multistage stiffness response. This work illustrates an unexplored and unprecedented capability of curved origami, which opens new applications in robotics for this particular family of origami patterns.

Electrochemical Oxidative Esterification of Thiophenols: Efficient Access to Sulfinic Esters

2020 ◽  
Vol 17 (7) ◽  
pp. 540-547
Author(s):  
Chun-Hui Yang ◽  
Cheng Wu ◽  
Jun-Ming Zhang ◽  
Xiang-Zhang Tao ◽  
Jun Xu ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Efficient Method ◽  
High Efficiency ◽  
Building Blocks ◽  
Constant Current ◽  
Good Efficiency ◽  
Oxidative Esterification ◽  
Efficient Access ◽  
New Applications ◽  
Sulfinic Esters

Background: The sulfinic esters are important and useful building blocks in organic synthesis. Objective: The aim of this study was to develop a simple and efficient method for the synthesis of sulfinic esters. Materials and Methods: Constant current electrolysis from thiols and alcohols was selected as the method for the synthesis of sulfinic esters. Results and Discussion: A novel electrochemical method for the synthesis of sulfinic esters from thiophenols and alcohols has been developed. Up to 27 examples of sulfinic esters have been synthesized using the current methods. This protocol shows good functional group tolerance as well as high efficiency. In addition, this protocol can be easily scaled up with good efficiency. Notably, heterocycle-containing substrates, including pyridine, thiophene, and benzothiazole, gave the desired products in good yields. A plausible reaction mechanism is proposed. Conclusion: This research not only provides a green and efficient method for the synthesis of sulfinic esters but also shows new applications of electrochemistry in organic synthesis. It is considered that this green and efficient synthetic protocol used to prepare sulfinic esters will have good applications in the future.

Progress in high-power high-efficiency VCSEL arrays

2009 ◽  
Author(s):  
Jean-Francois Seurin ◽  
Guoyang Xu ◽  
Viktor Khalfin ◽  
Alexander Miglo ◽  
James D. Wynn ◽  
...  
Keyword(s):  
High Power ◽  
High Efficiency ◽  
Vcsel Arrays

scholarly journals Near-field thermophotovoltaics for efficient heat to electricity conversion at high power density

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rohith Mittapally ◽  
Byungjun Lee ◽  
Linxiao Zhu ◽  
Amin Reihani ◽  
Ju Won Lim ◽  
...  
Keyword(s):  
Power Density ◽  
High Power ◽  
High Efficiency ◽  
Near Field ◽  
Electrical Power ◽  
Photovoltaic Cells ◽  
High Power Density ◽  
Pv Cell ◽  
Electrical Power Output ◽  
Power Densities

AbstractThermophotovoltaic approaches that take advantage of near-field evanescent modes are being actively explored due to their potential for high-power density and high-efficiency energy conversion. However, progress towards functional near-field thermophotovoltaic devices has been limited by challenges in creating thermally robust planar emitters and photovoltaic cells designed for near-field thermal radiation. Here, we demonstrate record power densities of ~5 kW/m2 at an efficiency of 6.8%, where the efficiency of the system is defined as the ratio of the electrical power output of the PV cell to the radiative heat transfer from the emitter to the PV cell. This was accomplished by developing novel emitter devices that can sustain temperatures as high as 1270 K and positioning them into the near-field (<100 nm) of custom-fabricated InGaAs-based thin film photovoltaic cells. In addition to demonstrating efficient heat-to-electricity conversion at high power density, we report the performance of thermophotovoltaic devices across a range of emitter temperatures (~800 K–1270 K) and gap sizes (70 nm–7 µm). The methods and insights achieved in this work represent a critical step towards understanding the fundamental principles of harvesting thermal energy in the near-field.

scholarly journals Influence of Casting Solvents on CO2/CH4 Separation Using Polysulfone Membranes

Membranes ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 286
Author(s):  
Roba M. Almuhtaseb ◽  
Ahmed Awadallah-F ◽  
Shaheen A. Al-Muhtaseb ◽  
Majeda Khraisheh
Keyword(s):  
High Efficiency ◽  
In Situ Synthesis ◽  
Separation Process ◽  
Polymeric Membranes ◽  
Gas Mixture ◽  
Manufacturing Cost ◽  
Binary Gas Mixture ◽  
Maximum Permeability ◽  
Polysulfone Membranes

Polysulfone membranes exhibit resistance to high temperature with low manufacturing cost and high efficiency in the separation process. The composition of gases is an important step that estimates the efficiency of separation in membranes. As membrane types are currently becoming in demand for CO2/CH4 segregation, polysulfone will be an advantageous alternative to have in further studies. Therefore, research is undertaken in this study to evaluate two solvents: chloroform (CF) and tetrahydrofuran (THF). These solvents are tested for casting polymeric membranes from polysulfone (PSF) to separate every single component from a binary gas mixture of CO2/CH4. In addition, the effect of gas pressure was conducted from 1 to 10 bar on the behavior of the permeability and selectivity. The results refer to the fact that the maximum permeability of CO2 and CH4 for THF is 62.32 and 2.06 barrer at 1 and 2 bars, respectively. Further, the maximum permeability of CF is 57.59 and 2.12 barrer at 1 and 2 bars, respectively. The outcome selectivity values are 48 and 36 for THF and CF at 1 bar, accordingly. Furthermore, the study declares that with the increase in pressure, the permeability and selectivity values drop for CF and THF. The performance for polysulfone (PSF) membrane that is manufactured with THF is superior to that of CF relative to the Robeson upper bound. Therefore, through the results, it can be deduced that the solvent during in-situ synthesis has a significant influence on the gas separation of a binary mixture of CO2/CH4.

Design of a cascade high-power source with high efficiency

2018 ◽  
Author(s):  
Gangxiong Wu ◽  
Yanyu Wei ◽  
Qian Li ◽  
Xia Lei ◽  
Chong Ding ◽  
...  
Keyword(s):  
High Power ◽  
High Efficiency ◽  
Power Source

High-Power Power GaAs and High-Efficiency Ion-Implanted FETs for C and X Bands

2005 ◽  
Author(s):  
S. Yanagawa ◽  
Y. Yamada ◽  
M. Itoh ◽  
K. Arai ◽  
N. Tomita
Keyword(s):  
High Power ◽  
High Efficiency ◽  
Ion Implanted
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