Design Method of Freeform Surface Optical Systems with Low Coupling Position Error Sensitivity

Freeform off-axis reflective systems are significantly more difficult to align and assemble owing to their asymmetric surface shapes and system structures. In this study, a freeform surface system design method with low coupling position error sensitivity (FCPESM) was proposed. First, we established a mathematical model of a reflective system when it was perturbed by coupling position errors and used the clustering-microelement method to establish the coupling error sensitivity evaluation function. The evaluation function was then applied to the design process of a freeform surface off-axis three-mirror optical system. The results showed that the FCPESM optical design method can significantly relax the assembly tolerance requirements of optical systems on the basis of ensuring image performance. In this study, the reflective system was perturbed by tilt and decenter simultaneously, and the disturbance mechanism of position errors on optical systems was further improved. Through this research, freeform surface systems with both image performance and error sensitivity can be obtained, which makes freeform off-axis reflective systems with better engineering realizability

Superelastic 3D Assembled Clay/Graphene Aerogels for Continuous Solar Desalination and Oil/Organic Solvent Absorption

Abstract Superelastic, arbitrary‐shaped, and 3D assembled clay/graphene aerogels (CGAs) are fabricated using commercial foam as sacrificial skeleton. The CGAs possess superelasticity under compressive strain of 95% and compressive stress of 0.09–0.23 MPa. The use of clay as skeletal support significantly reduces the use of graphene by 50%. The hydrophobic CGAs show high solvent absorption capacity of 186–519 times its own weight. Moreover, both the compression and combustion methods can be adopted for reusing the CGAs. In particular, it is demonstrated a design of 3D assembled hydrophilic CGA equipped with salt collection system for continuous solar desalination. Due to energy recovery and brine transport management promoted by this design, the 3D assembled CGA system exhibits an extremely high evaporation rate of 4.11 kg m−2 h−1 and excellent salt‐resistant property without salt precipitation even in 20 wt% brine for continuous 36 h illumination (1 kW m−2), which is the best reported result from the solar desalination devices. More importantly, salts can be collected conveniently by squeezing and drying the solution out of the salt collection system. The work provides new insights into the design of 3D assembled CGAs and advances their applications in continuous solar desalination and efficient oil/organic solvent adsorption

A novel (La0.2Ce0.2Gd0.2Er0.2Tm0.2)2(WO4)3 high-entropy ceramic material for thermal neutron and gamma-ray shielding

In this study, a new type of (La0.2Ce0.2Gd0.2Er0.2Tm0.2)2(WO4)3 single-phase high-entropy ceramic (HEC) powder was designed, prepared by solid-phase synthesis, and evenly mixed into an epoxy resin (EP) matrix to test the thermal neutron and γ-ray shielding performance. In terms of γ-ray shielding, (La0.2Ce0.2Gd0.2Er0.2Tm0.2)2(WO4)3 showed a higher lead equivalent value than EP at 65 keV, indicating a clear shielding effect in the feeble absorbing area of lead-based and bismuth-based materials; moreover, (La0.2Ce0.2Gd0.2Er0.2Tm0.2)2(WO4)3 showed good γ-ray shielding performance in both low-energy and medium-energy regions. In terms of thermal neutron shielding, the composite with the highest HEC content (EP/W3) had a nearly 100% shielding efficiency, while that of EP was approximately 50%, indicating that this material has favorable thermal neutron and γ-ray shielding performance. Moreover, the thermal conductivity of the resulting composite material was lower than 0.3 W·m−1·K−1, the tensile strength was higher than 10 MPa, and the density was lower than 1.5 g·cm−3. All these results suggest that (La0.2Ce0.2Gd0.2Er0.2Tm0.2)2(WO4)3 is a candidate radiation shielding material

The multi-faceted role of retinoid X receptor in cardiovascular diseases

Retinoid X receptors (RXRs) are members of ligand-dependent transcription factors whose effects on a diversity of cellular processes, including cellular proliferation, the immune response, and lipid and glucose metabolism. Knock out of RXRα causes a hypoplasia of the myocardium which is lethal during fetal life. In addition, the heart maintains a well-orchestrated balances in utilizing fatty acids (FAs) and other substrates to meet the high energy requirements. As the master transcriptional regulators of lipid metabolism, RXRs become particularly important for the energy needs of the heart. Accumulating evidence suggested that RXRs may exert direct beneficial effects in the heart both through heterodimerization with other nuclear receptors (NRs) and homodimerization, thus standing as suitable targets for treating in cardiovascular diseases. Although compounds that target RXRs are promising drugs, their use is limited by toxicity. A better understanding of the structural biology of RXRs in cardiovascular disease should enable the rational design of more selective nuclear receptor modulators to overcome these problems. Here, this review summarizes a brief overview of RXRs structure and versatility of RXR action in the control of cardiovascular diseases. And we also discussed the therapeutic potential of RXR ligand

A compact aqueous K-ion Micro-battery by a Self-shrinkage assembly strategy

Micro-batteries are promising power sources to drive miniaturized or portable electronic devices due to their higher energy density than micro-supercapacitors. Current micro-batteries still suffer from relatively large footprint and unsatisfactory areal electrochemical performance caused by loose electrode structure. Here, we develop a compact aqueous K-ion micro-battery through the self-shrinking of reduced graphene oxide hydrogel to realize small footprint and high areal capacity at the same time. With a volume of as small as 0.00381 cm(-3), this micro-battery delivers the highest areal capacity (5.1 mAh cm(-2)) and energy density (4.78 mWh cm(-2)) among all reported micro-batteries. Meanwhile, this micro-battery can be prepared into different shapes and attached onto a range of animals (ants, crabs and butterflies, etc.) for wide applications

Manganese-Doped Carbon Dots for Magnetic Resonance/Optical Dual-Modal Imaging of Tiny Brain Glioma

Brain gliomas are life-threatening diseases with low survival rates. Early detection and accurate intraoperative location of brain gliomas is vital to improving the prognosis. Herein, we synthesized manganese (Mn)-doped carbon dots (CDs) as magnetic resonance (MR)/optical dual-modal imaging nanoprobes by a one-pot green microwave-assisted route. These ultra-small-sized Mn-doped CDs possess distinct excitation-dependent photoluminescent emissions, high <i>r</i>₁ relaxivity, and low cytotoxicity. The in vivo MR imaging and ex vivo optical imaging of mouse brain with tiny glioma demonstrate that the Mn-doped CDs could lead to an enhanced MR <i>T</i>₁ contrast effect in the tiny brain glioma region, disclosing the great promise of these Mn-doped CDs as MR/optical dual-modal imaging nanoprobes for detection and intraoperative location of tiny brain gliomas

Fixture-free omnidirectional prestretching fabrication and integration of crumpled in-plane micro-supercapacitors

Multidimensional folded structures with elasticity could provide spatial charge storage capability and shape adaptability for micro-supercapacitors (MSCs). Here, highly crumpled in-plane MSCs with superior conformality are fabricated in situ and integrated by a fixture- free omnidirectional elastic contraction strategy. Using carbon nanotube microelectrodes, a single crumpled MSC holds an ultrahigh volumetric capacitance of 9.3 F cm(-3), and its total areal capacitance is 45 times greater than the initial state. Experimental and theoretical simulation methods indicate that strain-induced improvements of adsorption energy and conductance for crumpled microelectrodes are responsible for the prominent enhancement of electrochemical performance. With outstanding morphological randomicity, the integrated devices can serve as smart coatings in moving robots, withstanding extreme mechanical deformations. Notably, integration on a spherical surface is possible by using a spherical mask, in which a small area of the microdevice array (3.9 cm(2)) can produce a high output voltage of 100 V

Compact Assembly and Programmable Integration of Supercapacitors

Microsized supercapacitors (mSCs) with small volume, rapid charge-discharge rate, and ultralong cyclic lifetime are urgently needed to meet the demand of miniaturized portable electronic devices. A versatile self-shrinkage assembling (SSA) strategy to directly construct the compact mSCs (CmSCs) from hydrogels of reduced graphene oxide is reported. A single CmSC is only 0.0023 cm(3) in volume, which is significantly smaller than most reported mSCs in fiber/yarn and planar interdigital forms. It exhibits a high capacitance of up to 68.3 F cm(-3) and a superior cycling stability with 98% capacitance retention after 25 & x202f;000 cycles. Most importantly, the SSA technique enables the CmSC as the building block to realize arbitrary, programmable, and multi-dimensional integration for adaptable and complicated power systems. By design on mortise and tenon joint connection, autologous integrated 3D interdigital CmSCs are fabricated in a self-holding-on manner, which thus dramatically reduces the whole device volume to achieve the high-performance capacitive behavior. Consequently, the SSA technique offers a universal and versatile approach for large-scale on-demand integration of mSCs as flexible and transformable power sources

Moisture-Electric–Moisture-Sensitive Heterostructure Triggered Proton Hopping for Quality-Enhancing Moist-Electric Generator

Highlights An efficient moist-electric generator with ultra-fast electric response to moisture is achieved by triggering Grotthuss protons hopping in the moisture-electric–moisture-sensitive heterostructure. The moist-electric generator produces a quick response (0.435 s), an unprecedented ultra-fast response rate of 972.4 mV s−1 to alternating moisture stimulation and stable output for 8 h. An obstructive sleep apnea hypoventilation syndrome diagnostic system based on a moist-electric generator was developed to monitor hypopnea and apnea in real time and successfully diagnose them with early warning