scholarly journals Porous Functionalized Polymers enable Generating and Transporting Hyperpolarized Arbitrary Solutions.

Author(s):  
Théo El Darai ◽  
Samuel Cousin ◽  
Quentin Chappuis ◽  
Morgan Ceillier ◽  
James Kempf ◽  
...  

Abstract Hyperpolarization by dissolution dynamic nuclear polarization (dDNP) has brought highly sensitive magnetic resonance to reality and has triggered the development of a plethora of promising applications in spectroscopy and imaging. Unfortunately, some severe limitations still restrain its widespread use, amongst which the experimental complexity, the need for trained personnel, and excessive prices. Broad democratization of dDNP would require remote preparation of hyperpolarized samples in dedicated facilities and transport over long distances to the point of use. We have recently pioneered a new concept in which transport over hours was enabled by formulation of 13C-labelled molecules into micro-crystallites. However, the proposed methods lacked both versatility and biocompatibility. Here, we propose a new approach relying on a new generation of hyperpolarizing polymers (HYPOPs), extremely easy to synthesize, and that bear a dual function. Arbitrary solutions, easily impregnated into these radical-containing porous HYPOPs, can be hyperpolarized within 20 min with a polarization level exceeding P(13C) > 25% in the solid state, and further stored for hours in view of transport to a remote point of use.

Author(s):  
David D. Nolte

Galileo’s parabolic trajectory launched a new approach to physics that was taken up by a new generation of scientists like Isaac Newton, Robert Hooke and Edmund Halley. The English Newtonian tradition was adopted by ambitious French iconoclasts who championed Newton over their own Descartes. Chief among these was Pierre Maupertuis, whose principle of least action was developed by Leonhard Euler and Joseph Lagrange into a rigorous new science of dynamics. Along the way, Maupertuis became embroiled in a famous dispute that entangled the King of Prussia as well as the volatile Voltaire who was mourning the death of his mistress Emilie du Chatelet, the lone female French physicist of the eighteenth century.


2015 ◽  
Vol 4 (2) ◽  
pp. 304 ◽  
Author(s):  
Bill Chiu ◽  
Shih-Cheng Hu ◽  
Angus Shiue ◽  
Yu-Yun Shiue ◽  
Zhe-Yu Huang

The trend toward narrower line width in semiconductor manufacturing has made contamination control more and more important. The presence of moisture in wafer containers, such as front opening unified pods (FOUP), can lead to the native oxide residues growth, metal corrosion, and thin film cracking on wafer surfaces. Accordingly, decreasing contamination methods and improving factory efficiency are continuously researched. Single or multi-layer particulate shields on top of wafers in FOUPs may be used to prevent pollutant accumulation. In addition, point-of-use (POU) filtration may also been used to control particle contamination in FOUPs during wafer transformation and storage. The demand for stricter filtration led to the usage of 0.10 and 0.20 µm membranes to control the contamination. However, with the introduction of finer membranes end users may have concerns about deleterious remainders on wafers from undergoing filtration. There are a total of 25 pieces of wafers in the FOUP and the arrangement is from the bottom (wafer No. 1) to the top (wafer No. 25) with arising manner. Purging FOUPs to expel moisture vapors with Clean Dry Air (CDA) is one of the most popular methods.There was no previous research for investigating the purge performance on new-generation 450mm FOUPs. This research aims to study main factors influencing the performance of the purge system on 450mm FOUPs, including moisture concentration, CDA flow rate, and filter pressure.


Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2508
Author(s):  
Osama Nasr ◽  
Jian-Ru Jiang ◽  
Wen-Shuo Chuang ◽  
Sheng-Wei Lee ◽  
Chih-Yen Chen

In this article, we demonstrate a facile, rapid, and practical approach to growing high-quality Cu2S nanosheets decorated with Ag nanoparticles (NPs) through the galvanic reduction method. The Ag/Cu2S nanosheets were efficiently applied to the surface-enhanced Raman scattering (SERS) and photocatalytic degradation applications. The photodegradation of RhB dye with the Ag/Cu2S nanosheets composites occurred at a rate of 2.9 times faster than that observed with the undecorated Cu2S nanosheets. Furthermore, the Ag/Cu2S nanosheets displayed highly sensitive SERS detection of organic pollutant (R6G) as low as 10−9 M. The reproducibility experiments indicated that the Ag/Cu2S nanosheets composites could be used for dual functionality in a new generation of outstandingly sensitive SERS probes for detection and stable photocatalysts.


2021 ◽  
Vol 2091 (1) ◽  
pp. 012038
Author(s):  
M F Karavay ◽  
A M Mikhailov

Abstract The paper discusses On-Board Computing Control Systems (OBCS) in astronautics, avionics, autonomous mobile devices, robotics, weapons control and multi-core microprocessors. This is sort of a “backbone”, which unites many sensors, calculators, control and executive devices. The architecture of these networks was developed some 30-40 years ago. At that time, these systems met the technical conditions in terms of dynamics and reliability. Nowadays, these systems must perform their functions for 10 to 15 years without maintenance. The performance of system networks must be high enough to solve such tasks as monitoring “swarms” that comprise hundreds of objects or work as a “garbage collectors” in space orbits. Nevertheless modern system networks continue to be based on bus or multi-bus architectures. Since these systems are serial for active nodes, a multi-bus solution is a main way to increase the performance of networks by using very high frequencies that amount to 2 ÷ 4 GHz. It’s an extensive path of development, which is problematic. More acceptable would be an intensive path of development, which, in electronics and computer engineering, is associated with the parallelism of task execution. It means that the operating frequencies may not be ultra-high, not exceeding that of modern devices for frequencies of 10 – 600 MHz. However, such devices should work in a parallel mode. The paper proposes a new approach to designing of heterogeneous parallel control system networks, solving parallel tasks, and a conflict-free management of “passive” nodes. To the best of our knowledge, such control system networks are not available as yet.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takashi Kanadome ◽  
Natsumi Hoshino ◽  
Takeharu Nagai ◽  
Tomoki Matsuda ◽  
Takeshi Yagi

AbstractClustered protocadherins (Pcdhs), which are cell adhesion molecules, play a fundamental role in self-recognition and non-self-discrimination by conferring diversity on the cell surface. Although systematic cell-based aggregation assays provide information regarding the binding properties of Pcdhs, direct visualization of Pcdh trans interactions across cells remains challenging. Here, we present Förster resonance energy transfer (FRET)-based indicators for directly visualizing Pcdh trans interactions. We developed the indicators by individually inserting FRET donor and acceptor fluorescent proteins (FPs) into the ectodomain of Pcdh molecules. They enabled successful visualization of specific trans interactions of Pcdh and revealed that the Pcdh trans interaction is highly sensitive to changes in extracellular Ca2+ levels. We expect that FRET-based indicators for visualizing Pcdh trans interactions will provide a new approach for investigating the roles of Pcdh in self-recognition and non-self-discrimination processes.


Author(s):  
Royce Hanson

This chapter focuses on White Flint, a 400-acre obsolete commercial strip on Montgomery County's most congested roadway, and some of the important lessons it offers with respect to successful planning politics. The most recent of Montgomery's efforts in planning for mixed-use, transit-oriented activity centers, White Flint was envisioned as the best place to create a model for a new generation of land use policy. The chapter discusses the plan for White Flint, the key issues that needed to be resolved before it could move forward, and the project planners' new approach to zoning. White Flint illustrates the value of careful economic analysis; engagement of major property owners and community groups in making plans; and willingness to abandon old ideas in favor of new ones that fit the circumstances at hand. The case of White Flint also highlights the problems of bureaucratic and political resistance to new ways of financing infrastructure.


Author(s):  
Devdas Shetty ◽  
Claudio Campana ◽  
Nikolay Nazaryan ◽  
Louis Manzione

A great amount of research is being conducted to incorporate smart material actuators in aerospace applications such as (1) turbo fan engines (2) servo flap actuators for helicopter rotor control. For example, a piezoelectric stack actuator, coupled with mechanical or hydraulic amplification could provide the actuation required for the variable pitch fan system with a potentially higher level of reliability. In addition, piezoelectric actuation system could do so at a lower overall weight. However, there are limitations with existing piezoelectric stack actuators relative to power requirements. Therefore, a new approach has been investigated to improve these characteristics in order for piezoelectric stacks to be a feasible solution for these types of large scale applications. A new configuration involving dielectric, conductor, piezoelectric material in a particular sequence of stack actuation is examined and experimented. A nonlinear lumped parameter model of a piezoelectric stack has been developed to describe the behavior for the purpose of control actuation analysis.


Author(s):  
Bibhrajit Halder ◽  
Nilanjan Sarkar

A new approach to sensor and actuator fault detection in the presence of model uncertainty and disturbances, and its application to a wheeled mobile robot (WMR) are presented in this paper. Robust fault detection is important because of the universal existence of model uncertainties and process disturbances in most systems. This paper proposes a new approach, called robust nonlinear analytic redundancy (RNLAR) technique, to sensor and actuator fault detection for input-affine nonlinear multivariable dynamic systems in the presence of model-plant-mismatch and process disturbance. The proposed RNLAR can be used to design primary residual vectors (PRV) for nonlinear systems to detect sensor fault that are completely insensitive to both the model-plant-mismatch and process disturbance. It is shown that the PRV for actuator fault cannot be made completely insensitive to these factors. In order to overcome this problem, a nonlinear PRV design method to detect actuator faults is proposed where the PRVs are highly sensitive to the actuator faults and less sensitive to model-plant-mismatch and process disturbance. The proposed robust fault detection methodology is applied to a WMR and the simulation results are presented to demonstrate the effectiveness of this new approach.


NDT World ◽  
2015 ◽  
Vol 19 (4) ◽  
pp. 8-12 ◽  
Author(s):  
Солодов ◽  
Igor Solodov ◽  
Кройцбрук ◽  
Mark Kreutzbruck

The presence of a defect leads to a local decrease in rigidity for a certain mass of the material and therefore manifests in a particular characteristic frequency of the defect. A frequency match between the driving ultrasonic wave and this characteristic frequency provides a Local Defect Resonance (LDR) and results in efficient energy delivery from the wave into the defect. In this paper, such a selective ultrasonic activation of resonant defects is suggested to enhance nonlinear ultrasonic, optical and thermal defect responses. Multiple case studies demonstrate that the resonant excitation of a defect results in a high local vibration and enhancement of sensitivity in ultrasonic NDT and imaging of defects via laser vibrometry, thermosonics, nonlinearity and shearography readily measurable even for a few mW of ultrasonic power. The LDR-based NDT methods require much lower ultrasonic power to activate the defects that makes it possible to avoid high- power ultrasonic instrumentation.


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