While sufficient review articles exist on inductive short-range wireless power transfer (WPT), long-haul microwave WPT (MWPT) for solar power satellites, and ambient microwave wireless energy harvesting (MWEH) in urban areas, few studies focus on the fundamental modeling and related design automation of receiver systems. This article reviews the development of MWPT and MWEH receivers, with a focus on rectenna design automation. A novel rectifier model capable of accurately modeling the rectification process under both high and low input power is presented. The model reveals the theoretical boundary of radio frequency-to-direct current (dc) power conversion efficiency and, most importantly, enables an automated system design. The automated rectenna design flow is sequential, with the minimal engagement of iterative optimization. It covers the design automation of every module (i.e., rectifiers, matching circuits, Antennasae, and dc-dc converters). Scaling-up of the technique to large rectenna arrays is also possible, where the challenges in array partitioning and power combining are briefly discussed. In addition, several cutting-edge rectenna techniques for MWPT and MWEH are reviewed, including the dynamic range extension technique, the harmonics-based retro-directive technique, and the simultaneous wireless information and power transfer technique, which can be good complements to the presented automated design methodology.
Ultrashort pulse transmission has been recognized as a primary problem that fundamentally hinders the development of ultrafast electronics beyond the current nanosecond timescale. This requires a transmission line or waveguide that exhibits an all-pass frequency behavior for the transmitted ultrashort pulse signals. However, this type of waveguiding structure has not yet been practically developed; groundbreaking innovations and advances in signal transmission technology are urgently required to address this scenario. Herein, we present a synthesized all-pass waveguide that demonstrates record guided-wave controlling capabilities, including eigenmode reshaping, polarization rotation, loss reduction, and dispersion improvement. We experimentally developed two waveguides for use in ultrabroad frequency ranges (direct current (DC)-to-millimeter-wave and DC-to-terahertz). Our results suggest that the waveguides can efficiently transmit picosecond electrical pulses while maintaining signal integrity. This waveguide technology is an important breakthrough in the evolution of ultrafast electronics, providing a path towards frequency-engineered ultrashort pulses for low-loss and low-dispersion transmissions.
An experimental study is conducted on several retro-reflective beamforming schemes for wireless power transmission to multiple wireless power receivers (referred to herein as “targets”). The experimental results demonstrate that, when multiple targets broadcast continuous-wave pilot signals at respective frequencies, a retro-reflective wireless power transmitter is capable of generating multiple wireless power beams aiming at the respective targets as long as the multiple pilot signals are explicitly separated from one another by the wireless power transmitter. However, various practical complications are identified when the pilot signals of multiple targets are not appropriately differentiated from each other by the wireless power transmitter. Specifically, when multiple pilot signals are considered to be carried by the same frequency, the wireless power transmission performance becomes heavily dependent on the interaction among the pilot signals, which is highly undesirable in practice. In conclusion, it is essential for a retro-reflective wireless power transmitter to explicitly discriminate multiple targets’ pilot signals among each other.
This work presents an optimal design method of antenna aperture illumination for microwave power transmission with an annular collection area. The objective is to maximize the ratio of the power radiated on the annular collection area to the total transmitted power. By formulating the aperture amplitude distribution through a summation of a special set of series, the optimal design problem can be reduced to finding the maximum ratio of two real quadratic forms. Based on the theory of matrices, the solution to the formulated optimization problem is to determine the largest characteristic value and its associated characteristic vector. To meet security requirements, the peak radiation levels outside the receiving area are considered to be extra constraints. A hybrid grey wolf optimizer and Nelder-Mead simplex method is developed to deal with this constrained optimization problem. In order to demonstrate the effectiveness of the proposed method, numerical experiments on continuous apertures are conducted; then, discrete arrays of isotropic elements are employed to validate the correctness of the optimized results. Finally, patch arrays are adopted to further verify the validity of the proposed method.
In this paper, an in-band and out-of-band microwave wireless power-transmission characteristic analysis of a slot ring radome based on an approximate analytical method is proposed. The main contribution of this paper is that, in the approximate analysis of the ring radome, a unified expression of the incident field on the radome surface is derived with E-plane and H-plane scanning, and the ring is approximated as 30 segments of straight strips. Solving the corresponding 60 × 60 linear equations yields the electric current distribution along the ring strip. The magnetic current along the complementary slot ring is obtained by duality. Thanks to the fully analytical format of the current distribution, the microwave wireless power-transmission characteristics are efficiently calculated using Munk’s scheme. An example of a slot ring biplanar symmetric hybrid radome is used to verify the accuracy and efficiency of the proposed scheme. The central processing unit (CPU) time is about 690 s using Ansys HFSS software versus 2.82 s for the proposed method.
Human-robot (HR) collaboration (HRC) is an emerging research field because of the complementary advantages of humans and robots. An HRC framework for robotic assembly based on impedance control is proposed in this paper. In the HRC framework, the human is the decision maker, the robot acts as the executor, while the assembly environment provides constraints. The robot is the main executor to perform the assembly action, which has the position control, drag and drop, positive impedance control, and negative impedance control modes. To reveal the characteristics of the HRC framework, the switch condition map of different control modes and the stability analysis of the HR coupled system are discussed. In the end, HRC assembly experiments are conducted, where the HRC assembly task can be accomplished when the assembling tolerance is 0.08 mm or with the interference fit. Experiments show that the HRC assembly has the complementary advantages of humans and robots and is efficient in finishing complex assembly tasks.
Olefin solution polymerization can be used to obtain high-performance polyolefin materials that cannot be obtained via other polymerization processes. Polyolefin elastomers (POE) are a typical example. Due to cost, only a few linear α-olefins (e.g., 1-butene, 1-hexene, and 1-octene) are used as comonomers in solution polymerization in industry. However, α-olefin comonomers with other structures may have different effects on polymerization in comparison with common linear ones. Moreover, the properties of the corresponding materials may differ significantly. In this work, copolymers of ethylene with linear and end-cyclized α-olefins are synthesized using a metallocene catalyst. The copolymerization of ethylene with linear α-olefins results in a higher turn-over frequency (TOF) and lower incorporation than copolymerization with end-cyclized α-olefins, which may indicate that end-cyclized α-olefins have a higher coordination probability and lower insertion rate. In this reaction, the comonomer is distributed randomly in the polymer chain and efficiently destroys crystallization. End-cyclized α-olefins exhibit a much stronger crystallization destructive capacity (CDC) in the copolymer than linear α-olefins, possibly because linear α-olefins act mainly in the radial direction of the main chain of the polymer, while end-cyclized α-olefins act mainly in the axial direction of the main chain.
Light olefins are important organic building blocks in the chemicals industry. The main low-carbon olefin production methods, such as catalytic cracking and steam cracking, have considerable room for improvement in their utilization of hydrocarbons. This review provides a thorough overview of recent studies on catalytic cracking, steam cracking, and the conversion of crude oil processes. To maximize the production of light olefins and reduce carbon emissions, the perceived benefits of various technologies are examined. Taking olefin generation and conversion as a link to expand upstream and downstream processes, a targeted catalytic cracking to olefins (TCO) process is proposed to meet current demands for the transformation of oil refining into chemical production. The main innovations of this process include a multiple feedstock supply, the development of medium-sized catalysts, and a diameter-transformed fluidized-bed reactor with different feeding schemes. In combination with other chemical processes, TCO is expected to play a critical role in enabling petroleum refining and chemical processes to achieve low carbon dioxide emissions.
Refractory high-entropy alloys (RHEAs) have promising applications as the new generation of high-temperature alloys in hypersonic vehicles, aero-engines, gas turbines, and nuclear power plants. This study focuses on the microstructures and mechanical properties of the NbMoTaW(HfN)x (x = 0, 0.3, 0.7, and 1.0) RHEAs. The alloys consist of multiple phases of body-centered cubic (BCC), hafnium nitride (HfN), or multicomponent nitride (MN) phases. As the x contents increase, the grain size becomes smaller, and the strength gradually increases. The compressive yield strengths of the NbMoTaWHfN RHEA at ambient temperature, 1000, 1400, and 1800 °C were found to be 1682, 1192, 792, and 288 MPa, respectively. The high-temperature strength of this alloy is an inspiring result that exceeds the high temperature and strength of most known alloys, including high-entropy alloys, refractory metals, and superalloys. The HfN phase has a significant effect on strengthening due to its high structural stability and sluggish grain coarsening, even at ultra-high temperatures. Its superior properties endow the NbMoTaWHfN RHEA with potential for a wide range of engineering applications at ultra-high temperatures. This work offers a strategy for the design of high-temperature alloys and proposes an ultra-high-temperature alloy with potential for future engineering applications.
Subsurface geothermal energy storage has greater potential than other energy storage strategies in terms of capacity scale and time duration. Carbon dioxide (CO2) is regarded as a potential medium for energy storage due to its superior thermal properties. Moreover, the use of CO2 plumes for geothermal energy storage mitigates the greenhouse effect by storing CO2 in geological bodies. In this work, an integrated framework is proposed for synergistic geothermal energy storage and CO2 sequestration and utilization. Within this framework, CO2 is first injected into geothermal layers for energy accumulation. The resultant high-energy CO2 is then introduced into a target oil reservoir for CO2 utilization and geothermal energy storage. As a result, CO2 is sequestrated in the geological oil reservoir body. The results show that, as high-energy CO2 is injected, the average temperature of the whole target reservoir is greatly increased. With the assistance of geothermal energy, the geological utilization efficiency of CO2 is higher, resulting in a 10.1% increase in oil displacement efficiency. According to a storage-potential assessment of the simulated CO2 site, 110 years after the CO2 injection, the utilization efficiency of the geological body will be as high as 91.2%, and the final injection quantity of the CO2 in the site will be as high as 9.529 × 108 t. After 1000 years sequestration, the supercritical phase dominates in CO2 sequestration, followed by the liquid phase and then the mineralized phase. In addition, CO2 sequestration accounting for dissolution trapping increases significantly due to the presence of residual oil. More importantly, CO2 exhibits excellent performance in storing geothermal energy on a large scale; for example, the total energy stored in the studied geological body can provide the yearly energy supply for over 3.5 × 107 normal households. Application of this integrated approach holds great significance for large-scale geothermal energy storage and the achievement of carbon neutrality.
Hydrogen peroxide (H2O2) in situ electrosynthesis by O2 reduction reaction is a promising alternative to the conventional Fenton treatment of refractory wastewater. However, O2 mass transfer limitation, cathodic catalyst selectivity, and electron transfer in O2 reduction remain major engineering obstacles. Here, we have proposed a systematic solution for efficient H2O2 generation and its electro-Fenton (EF) application for refractory organic degradation based on the fabrication of a novel ZrO2/CMK-3/PTFE cathode, in which polytetrafluoroethylene (PTFE) acted as a hydrophobic modifier to strengthen the O2 mass transfer, ZrO2 was adopted as a hydrophilic modifier to enhance the electron transfer of O2 reduction, and mesoporous carbon CMK-3 was utilized as a catalyst substrate to provide catalytic active sites. Moreover, feasible mass transfer of O2 from the hydrophobic to the hydrophilic layer was designed to increase the contact between O2 and the reaction interface. The H2O2 yield of the ZrO2/CMK-3/PTFE cathode was significantly improved by approximately 7.56 times compared to that of the conventional gas diffusion cathode under the same conditions. The H2O2 generation rate and Faraday efficiency reached 125.98 mg·cm−2·h−1 (normalized to 5674.04 mmol·g−1·h−1 by catalyst loading) and 78.24% at −1.3 V versus standard hydrogen electrode (current density of −252 mA·cm−2), respectively. The high H2O2 yield ensured that sufficient OḢ was produced for excellent EF performance, resulting in a degradation efficiency of over 96% for refractory organics. This study offers a novel engineering solution for the efficient treatment of refractory wastewater using EF technology based on in situ high-yield H2O2 electrosynthesis.
The removal of emerging micropollutants in the aquatic environment remains a global challenge. Conventional routes are often chemically, energetically, and operationally intensive, which decreases their sustainability during applications. Herein, we develop an advanced chemical-free strategy for micropollutants decontamination that is solely based on sequential electrochemistry involving ubiquitous sulfate anions in natural and engineered waters. This can be achieved via a chain reaction initiated by electrocatalytic anodic sulfate (SO42−) oxidation to produce persulfate (S2O82−) and followed by a cathodic persulfate reduction to produce sulfate radicals (SO4̇−). These SO4̇− are powerful reactive species that enable the unselective degradation of micropollutants and yield SO42− again in the treated water. The proposed flow-through electrochemical system achieves the efficient degradation (100.0%) and total organic carbon removal (65.0%) of aniline under optimized conditions with a single-pass mode. We also reveal the effectiveness of the proposed system for the degradation of a wide array of emerging micropollutants over a broad pH range and in complex matrices. This work provides the first proof-of-concept demonstration using ubiquitous sulfate for micropollutants decontamination, making water purification more sustainable and more economical.
Tailoring water supply to achieve confined heating has proven to be an effective strategy for boosting solar interfacial evaporation rates. However, because of salt clogging during desalination, a critical point of constriction occurs when controlling the water rate for confined heating. In this study, we demonstrate a facile and scalable weaving technique for fabricating core-sheath photothermal yarns that facilitate controlled water supply for stable and efficient interfacial solar desalination. The core-sheath yarn comprises modal fibers as the core and carbon fibers as the sheaths. Because of the core-sheath design, remarkable liquid pumping can be enabled in the carbon fiber bundle of the dispersed super-hydrophilic modal fibers. Our woven fabrics absorb a high proportion (92%) of the electromagnetic radiation in the solar spectrum because of the weaving structure and the carbon fiber sheath. Under one-sun (1 kW·m−2) illumination, our woven fabric device can achieve the highest evaporation rate (of 2.12 kg·m−2·h−1 with energy conversion efficiency: 93.7%) by regulating the number of core-sheath yarns. Practical application tests demonstrate that our device can maintain high and stable desalination performance in a 5 wt% NaCl solution.
Interbasin water-transfer schemes provide an engineering solution for reconciling the conflict between water demand and availability. In the context of climate change, which brings great uncertainties to water resource distribution, interbasin water transfer plays an increasingly important role in the global water-food-energy nexus. However, the transfer of water resources simultaneously changes the hydrological regime and the characteristics of local water bodies, affecting biotic communities accordingly. Compared with high economic and technical inputs water-transfer projects require, the environmental and ecological implications of water-transfer schemes have been inadequately addressed. This work selects the largest water-transfer project in China, the South-to-North Water Diversion (SNWD) Project, to critically review its eco-environmental impacts on donor and recipient basins, as well as on regions along the diversion route. The two operated routes of the SNWD Project represent two typical water diversion approaches: The Middle Route uses an excavated canal, while the East Route connects existent river channels. An overview of the eco-environmental implications of these two routes is valuable for the design and optimization of future water-transfer megaprojects.
Microneedles (MNs) can be used for the topical treatment of skin disorders as they directly deliver therapeutics to the site of skin lesions, resulting in increased therapeutic efficacy while having minimum side effects. MNs are used to deliver different kinds of therapeutics (e.g., small molecules, macromolecules, nanomedicines, living cells, bacteria, and exosomes) for treating various skin disorders, including superficial tumors, wounds, skin infections, inflammatory skin diseases, and abnormal skin appearance. The therapeutic efficacy of MNs can be improved by integrating the advantages of multiple therapeutics to perform combination therapy. Through careful designing, MNs can be further modified with biomimetic structures for the responsive drug release from internal and external stimuli and to enhance the transdermal delivery efficiency for robust therapeutic outcomes. Some studies have proposed the use of drug-free MNs as a promising mechanotherapeutic strategy to promote wound healing, scar removal, and hair regeneration via a mechanical communication pathway. Although MNs have several advantages, the practical application of MNs suffers from problems related to industrial manufacture and clinical evaluation, making it difficult for clinical translation. In this study, we summarized the various applications, emerging challenges, and developmental prospects of MNs in skin disorders to provide information on ways to advance clinical translation.
B7 homolog 3 (B7-H3) has attracted much attention in glioblastoma (GBM) radioimmunotherapy (RIT) due to its abnormally high expression on tumor cells. In this study, we report that two specific humanized anti-human B7-H3 antibodies (hu4G4 and hu4H12) derived from mouse anti-human B7-H3 antibodies that were generated by computer-aided design and exclusively recognize membrane expression of B7-H3 by human glioma cells. Hu4G4 and hu4H12 were radiolabeled with 89Zr for RIT antibody screening. Micro-positron emission tomography (PET) imaging, biodistribution and pharmacokinetic (PK) analyses of 89Zr-labeled antibodies were performed in U87-xenografted models. 125I labelling of the antibodies for single-photon emission computed tomography (SPECT) imaging was also used to investigate the biological behavior of the antibodies in vivo. Furthermore, the pharmacodynamic (PD) of the 131I-labeled antibodies were evaluated in U87-xenografted mice and GL261 Red-FLuc-B7-H3 in situ glioma tumor models. Micro-PET imaging and biodistribution analysis with a gamma counter showed that 89Zr-deferoxamine (DFO)-hu4G4 had higher tumor targeting performance with lower liver uptake than 89Zr-DFO-(hu4H12, immunoglobulin G (IgG)). The biodistribution results of 125I-SPECT imaging were similar to those of 89Zr-PET imaging, though the biodistribution in long bone joints and the thyroid varied. The PD analysis results indicated that 131I-hu4G4 had an excellent therapeutic effect and high safety with no apparent toxicity. Interestingly, 131I-hu4G4 improved the tumor vasculature in tissues with higher expression of collagen type IV and platelet-derived growth factor receptor β (PDGFR-β) compared with control treatment, as determined by immunofluorescence (IF), which contributed to inhibiting tumor growth. Taken together, our data indicate that hu4G4 exhibits good tumor targeting and specificity, achieves low nonspecific concentrations in normal tissues, and has acceptable PK characteristics. 131I-hu4G4 also exerts effective antitumor effects with an ideal safety profile. Therefore, we expect hu4G4 to be an excellent antibody for the development of GBM RIT.
Amine transaminases (ATAs) catalyze the asymmetric amination of prochiral ketones or aldehydes to their corresponding chiral amines. However, the trade-off between activity and stability in enzyme engineering represents a major obstacle to the practical application of ATAs. Overcoming this trade-off is important for developing robustly engineered enzymes and a universal approach for ATAs. Herein, we modified the binding pocket of ω-ATA from Aspergillus terreus (AtATA) to identify the key amino acid residues controlling the activity and stability of AtATA toward 1-acetonaphthone. We discovered a structural switch comprising four key amino acid sites (R128, V149, L182, and L187), as well as the “best” mutant (AtATA_D224K/V149A/L182F/L187F; termed M4). Compared to the parent enzyme AtATA_D224K (AtATA-Pa), M4 increased the catalytic efficiency (kcat/Km1-acetonaphthone, where kcat is the constant of catalytic activities and is 10.1 min−1, Km1-acetonaphthone is Michaelis-Menten constant and is 1.7 mmol·L-1) and half-life (t1/2) by 59-fold to 5.9 L·min−1·mmol−1 and by 1.6-fold to 46.9 min, respectively. Moreover, using M4 as the biocatalyst, we converted a 20 mmol·L-1 aliquot of 1-acetonaphthone in a 50 mL scaled-up system to the desired product, (R)-(+)-1(1-naphthyl)ethylamine ((R)-NEA), with 78% yield and high enantiomeric purity (R > 99.5%) within 10 h. M4 also displayed significantly enhanced activity toward various 1-acetonaphthone analogs. The related structural properties derived by analyzing structure and sequence information of robust ATAs illustrated their enhanced activity and thermostability. Strengthening of intramolecular interactions and expansion of the angle between the substrate-binding pocket and the pyridoxal 5′-phosphate (PLP)-binding pocket contributed to synchronous enhancement of ATA thermostability and activity. Moreover, this pocket engineering strategy successfully transferred enhanced activity and thermostability to three other ATAs, which exhibited 8%-22% sequence similarity with AtATA. This research has important implications for overcoming the trade-off between ATA activity and thermostability.
