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Since it is designable, metasurface was widely used in various fields, especially the design of polarization converters. However, most of the polarization converters currently designed can only work under normal incidence or small angle incidence, which hugely limits the application of the device. In this paper, a chiral metasurface based on the z-shaped unit cell, which can manipulate circular polarization wave, is proposed. The simulation result shows that this converter can maintain the polarization state of circular polarization after reflection from 8.18 to 13.988 GHz with a polarization conversion ratio of more than 90%. Moreover, the structure is insensitive to the incidence angle, which can keep a stable performance both for left-handed circularly polarized wave and right-handed circularly polarized waves as the incident angle increase to 75°. The proposed metasurface with simple structure and angular stability can be used in communication and polarization manipulating devices.

Electromagnetic (EM) waves carrying orbital angular momentum (OAM) exhibit phase vortex and amplitude singularity. Broadband OAM generation with high efficiency is highly desired with suggested applications such as broadband imaging and communications. In this paper, suspended metasurface structure achieving low-Q factor is proposed to realize broadband phase control and excellent reflection efficiency. Broadband vortex beam generation with OAM order of 1 and 2 are realized using the proposed suspended structure. Furthermore, by analyzing different metasurface aperture phase distribution schemes, the efficiency of the OAM generator is maximally achieved. The designs are validated by simulation and measurement. The proposed OAM generators work across 4–10 GHz with efficiency higher than 82%. This design provides a route to broadband metasurface realization and high efficiency OAM generation.

We characterize the nonlinearities of our previously designed 10 W class-J power amplifier with a carrier at 1.5 GHz. We employ numerical simulations and real time adjacent channel power ratio (ACPR) measurements on the fabricated prototype. The measurements are performed for a wideband code division multiple access (WCDMA) signal with 10.5 dB peak-to-average power ratio (PAPR) and 3.84 MHz bandwidth.

Abstract High-efficiency (HE) washers use 35–50% less water and about 50% less energy per load than conventional washers. However, there has been a consistent debate as to whether HE washers perform better or worse in garment care than conventional washers. Consumers need research-based information that would help them make informed decisions concerning the purchase of a clothes washer. The purpose of this study was to compare fabric hand, appearance retention (strain removal, color change, and fabric smoothness), and dimension stability (dimensional change and skewness change) after the specimens were repeatedly washed and dried for up to 20 cycles in three combinations of washer and dryer used: (a) conventional washer and dryer, (b) HE washer and conventional dryer, and (c) HE washer and dryer. The results showed that the specimens washed in the HE washer had better fabric hand and were smoother (fewer wrinkles) than those washed in the conventional washer. Conventional and HE washers performed similarly in color change, dimensional change, and skewness change. In regard to dryer, all results except those for stain removal showed no significant differences between the specimens dried in the conventional dryer and those dried in the HE dryer. In stain removal, when a softener was not used, the conventional dryer removed more stains from the specimens than the HE dryer. However, when a softener was used, the stains on the specimens dried in the conventional dryer were more difficult to remove than those on the specimens dried in the HE dryer.

Cogeneration allows the optimal use of the primary energy sources and significant reductions in carbon emissions. Its use has great potential for applications in the residential sector. This study aims to develop a methodology for thermal-economic optimisation of small-scale micro-gas turbine for cogeneration purposes, able to fulfil domestic energy needs with a thermal power out of 125 kW. A constrained non-linear optimisation model was built. The objective function is the maximisation of the annual worth from the combined heat and power, representing the balance between the annual incomes and the expenditures subject to physical and economic constraints. A genetic algorithm coded in the java programming language was developed. An optimal micro-gas turbine able to produce 103.5 kW of electrical power with a positive annual profit (i.e. 11,925 €/year) was disclosed. The investment can be recovered in 4 years and 9 months, which is less than half of system lifetime expectancy.

A highly efficient catalyst Fe–Co/sulfonated polystyrene (Fe–Co/SPS) was introduced and synthesized, which catalyzed BV oxidation of ketones with aqueous hydrogen peroxide to give the corresponding lactones in high yield and selectivity. Solid acid catalyst of Fe–Co/SPS has been prepared by using the 98-wt% sulfuric acid as the sulfonating agent and CoCl2 combined FeCl3 as sources of metal ions. Various physical–chemical characterizations including FT-IR, XRD, SEM and TGA, revealed that bimetallic ions Fe3+–Co2+ species in the sulfonated polystyrene framework were responsible for the catalytic activities. The BV reaction catalyzed by Fe–Co/SPS highlighted the special effects between metal ions and protonic acids as well as solvent-free heterogeneous catalytic oxidation with excellent conversion.

A high-power, high-efficiency, and high-speed white light-emitting-diode (LED) wireless transmitter is presented in this paper. This transmitter system consists of a gallium nitride field effect transistor (GaN FET) driver with push-pull structure, freewheeling circuit, and remaining carriers sweep-out circuit based on a phosphorescent white LED. A novel push-pull circuit structure with intensity modulation is used to increase the efficiency of the proposed transmitter to 94.2% at 12 Mb/s theoretical baud rate. Generally speaking, LED transmission speed is restricted by the remaining carriers in the junction capacitance. In this paper, we introduce an improved adjustable carrier sweep-out circuit to resolve this problem. High-frequency components in the signal are preemphasized by adding parallel freewheeling diodes between the drain and source of the GaN drivers. Test results show that the power efficiency is 93.17% with -3 dB bandwidth at 8.3 MHz. The results also show that the architecture proposed in this paper allows the baud rate of the transmitter to reach 10 Mb/s with bit error rate below 10-5, which meets the IEEE 802.11 b requirements at distances farther than 1 m.

In this paper, a design approach for a high-efficiency concurrent dual-band power amplifier (PA) with precise harmonic control up to third order is proposed. With the precise harmonic control approach, the high-efficiency performance of the PA can be improved at two arbitrary wide interval frequencies. Based on the inherent impedance matching flexibility of the continuous Class-F (CCF) operating mode, the design spaces of fundamental and harmonic impedances of the PA are largely expanded. The optimal impedances of a CCF PA mode at the internal current-generator (I-gen) plane and package plane are investigated, respectively, and a novel dual-band matching network topology is designed to simultaneously present required load impedances at the fundamental and harmonic impedances of both operation frequencies. First, a harmonic control network is designed to control the harmonic impedances precisely for CCF operation. Then, the fundamental impedances are synthesized using the real frequency technique. To verify the validity of proposed methodology, a dual-band CCF PA operating at 2.6 and 3.5 GHz is designed, fabricated, and measured. The measurement results show that the peak drain efficiency is 76.7% with an output power 42.4 dBm at the lower band and 72.8% with an output power 41.1 dBm at the upper band.

In this paper, a new methodology using a distributed ladder structure with finite transmission zero at finite frequencies is proposed for designing a broadband high-efficiency continuous Class-F (CCF) power amplifier (PA). The approach of realizing finite transmission zeros in Richard domain using Real Frequency Technique is first presented. By applying the proposed approach, the characteristics of the driving point impedance (DPI) of the proposed structure can be deduced and obtained in theory. Furthermore, the synthesis methods in Richard domain are extended to synthesize the DPI of the proposed structure. Four types of distributed elements are investigated to synthesize the DPI of the proposed structure. This proposed structure can improve the performance of the CCF PA when the bandwidth approaches an octave as the finite transmission zero can be used to control the second harmonic impedance of the lower frequency which is near the upper frequency of the operation band. To verify the validity of the proposed method, a broadband high-efficiency CCF PA working from 1.15 to 2.2 GHz is designed. Experimental results show that the fabricated PA achieves 11.3-13.7 dB power gain and 40.5-43.2 dBm output power in the operation band. And the PA has also achieved a high-efficiency characteristic of 70%-83% drain efficiency (DE) over the whole operation bandwidth.

Existing piezoelectric vibration energy harvesting circuits require auxiliary power for the switch control module and are difficult to adapt to broadband piezoelectric vibration energy harvesters. This paper proposes a self-powered and low-power enhanced double synchronized switch harvesting (EDSSH) circuit. The proposed circuit consists of a low-power follow-up switch control circuit, reverse feedback blocking-up circuit, synchronous electric charge extraction circuit and buck-boost circuit. The EDSSH circuit can automatically adapt to the sinusoidal voltage signal with the frequency of 1 to 312.5 Hz that is output by the piezoelectric vibration energy harvester. The switch control circuit of the EDSSH circuit works intermittently for a very short time near the power extreme point and consumes a low amount of electric energy. The reverse feedback blocking-up circuit of the EDSSH circuit can keep the transmission efficiency at the optimal value. By using a charging capacitor of 1 mF, the charging efficiency of the proposed EDSSH circuit is 1.51 times that of the DSSH circuit.

This paper proposes a method for optimizing and designing a wireless power transfer system operating at 13.56 MHz. It can be used as guidelines for designing coils for the new-trending technology that enables NFC devices to not only to communicate but also to charge. Since NFC wireless charging is an emerging technology, it is of interest to propose optimizations and a dedicated circuit design for such systems. This work proposes an optimization procedure to calculate the dimensions of a transmitter and receiver pair that assures the highest efficiency while considering all possible positions of a receiver that is placed on a desired surface. This procedure seeks to facilitate and automate the design of rectangular-shaped coils, whereas the literature proposes mainly square-shaped coils. Afterwards, a circuit analysis was conducted, and the series-parallel compensation network is proposed as the most promising topology of the receiver to assure a low efficiency sensibility to load variations for 13.56 MHz wireless power transfer systems. A pair of optimized transmitter and receiver coils is prototyped, and the experimental results are tested against the theory. The transmitter of 7 cm×11.4 cm and receiver of 4 cm ×4 cm are separated by 10 mm. The receiver can move on a surface of 8 cm ×12 cm and the load can vary from 36 Ω to 300 Ω while assuring a minimum and maximum efficiency of 80% and 88.3%, respectively.

In this article, we discuss the use of a third harmonic component to the drive voltage on the grid of an inductive output tube (IOT). High-efficiency IOTs are typically characterized by efficiencies up to 70%–75%. However, the achievement of efficiencies greater than 80% would substantially reduce the operating costs of next-generation accelerators. In order to achieve this goal, we consider the addition of a third harmonic component to the drive signal on the grid of an IOT. The use of a third harmonic drive component in IOT guns has been considered in order to apply such a gun as the injector of radio frequency linear accelerators (RF linacs). Here, we consider that the IOT will be used to provide the rf power to drive RF linacs and apply the third harmonic with the intention of increasing the efficiency of the RF output of the IOT. We consider a model IOT with a 700-MHz resonant cavity and using an annular beam with a voltage of 30 kV, an average current of 6.67 A yielding a perveance of about $1.3~\mu \text{P}$. We simulate this IOT using the NEMESIS simulation code which has been successfully validated by comparison with the K5H90W-2 IOT developed by Communications and Power Industries. It is found that the effect of the third harmonic on the efficiency is greatest when the phase of the third harmonic is shifted by $\pi $ radians with respect to the fundamental drive signal and with third harmonic powers greater than about 50% that of the fundamental drive power. For the present example, we show that efficiencies approaching 86% are possible by this means. [ABSTRACT FROM AUTHOR]

Lead-free BaTi 0.89 Sn 0.11 O 3 (BTSn) ceramic was elaborated via a solid-state reaction method and its dielectric, ferroelectric, energy storage, electromechanical as well as electrocaloric properties were investigated at 25 kV/cm. Pure perovskite structure was confirmed by X-ray diffraction analysis. The maximum of the dielectric constant was found to be 17390 at 41 °C. The enhanced total energy density, the recovered energy density, and the energy storage efficiency of 92.7 mJ/cm3, 84.4 mJ/cm3, and 91.04 %, respectively, were observed at 60 °C. In contrast, the highest energy storage efficiency of 95.87 % was obtained at 100 °C. At room temperature, the electromechanical strain and the large-signal piezoelectric coefficient reached a maximum of 0.07 % and 280 pm/V. The large electrocaloric effect of 0.71 K and the electrocaloric responsivity of 0.28 × 10-6 K mm/kV at 49 °C under 25 kV/cm were indirectly determined via Maxwell approach and the measured ferroelectric polarization P (E , T). The electrocaloric response was also modelled by exploiting the Landau-Ginzburg-Devonshire (LGD) phenomenological theory. The modelling result of 0.61 K at 50 °C under 25 kV/cm supports the experimental findings. We conclude that BTSn lead-free ceramic is a promising candidate for potential applications in high-efficiency energy storage devices and solid-state refrigeration technology. [ABSTRACT FROM AUTHOR]

This article presents a low-cost, high-efficiency, and full-metal reflectarray (RA) antenna with mechanical beam-steerable capabilities. A unit cell (UC) implemented by a metal cylinder with a cuboid-shaped notch is proposed to achieve a 1 bit reflection phase (0 and $\pi $) for the transverse electric (TE) and transverse magnetic (TM) normal incidence waves. The proposed UCs can be employed to construct an RA antenna with 2-D beam-steerable abilities. For demonstration, the RA antennas with six different beam directions are presented as examples, by simply adjusting the rotations of the UCs. The impedance matches of the RA antenna are all below −10 dB from 22 to 33 GHz, and the measured radiation patterns of the RA antenna are all highly consistent with the simulated counterparts for the six different beam direction scenarios. A 1.5 dB gain drop bandwidth of approximately 20% from 24.7 to 30 GHz and a peak realized gain of 18.9 dBi at 26 GHz are experimentally obtained for the RA antenna with radiation patterns at broadside. Compared to the substrate-based UCs loaded with p-i-n diodes, the proposed UCs have full-metal structures without using any active RF components and dielectric substrates, leading to the high total efficiency of the proposed RA antenna. Due to the low-cost, high-efficiency, and high-power handling properties, the proposed RA antenna can provide a fixed or scanning beam and is a good candidate for 5G millimeter-wave communication applications. [ABSTRACT FROM AUTHOR]

• The importance of deep NIR sensitizers for maximal SSM-DSC performance is shown. • A SSM-DSC with a power conversion efficiency of >11% is realized for the first time. • Sensitizer and redox shuttle selection has enabled >2.3 V from a SSM-DSC at >11% PCE. • Minimal potential losses allow for applications in catalysis/solar fuel generation. • A versatile architecture compatible with various solar cell technologies is shown. A sequential series multijunction dye-sensitized solar cell (SSM-DSC) designed to minimize optical and free energy losses to enable higher device performance is reported. Efficient photon management of solar spectrum irradiation was made possible by: controlling TiO 2 film thickness in each subcell leading to balanced photocurrent, careful sensitizer selection based on absorption breadth and intensity for each subcell, and minimizing photon losses by application of an anti-reflective coating with an immersion oil between subcells. By using these strategies with a deep NIR absorbing sensitizer, an SSM-DSC device based on D35/B11/Black Dye demonstrated an overall power conversion efficiency of >11% with a photovoltage of 2.3 V from a single illuminated area device. The PCE of the SSM-DSC is significantly higher than any of the individual subcell in the mechanical stack. This approach has led to a higher performing device than the prior reported high efficiency SSM-DSC devices based on D35/B11/B11 or the all organic dye SSM-DSC based on D35/MK2/AP25 + D35. [ABSTRACT FROM AUTHOR]

Spectroscopic properties of Nd3+-doped phosphate glass for three-level laser were investigated for the first time. A 60 nm blue-shift of the three-level transition fluorescence spectrum was achieved by changing the host material from traditional silica glass to phosphate glass. An 880-nm all-fiber laser with a world-record slope efficiency of 42.8% was demonstrated with 25-cm-long 0.25-wt.% Nd3+-doped phosphate fiber. Our research shows that Nd3+-doped phosphate glass is a high-efficiency material for laser operation below 900 nm. [ABSTRACT FROM AUTHOR]

Geometric metasurfaces have shown superior phase control capacity owing to the geometric nature of their phase profile. The existing geometric metasurfaces are generally composed of metal-dielectric composites or all-dielectric subwavelength structures. Here, a novel configuration, all-metallic structure, is proposed to achieve broadband and high-performance electromagnetic wavefront manipulation based on the geometric phase. A catenary model is built to describe the optical dispersion and guide the design of metasurfaces. Two metadevices including a beam deflector and a hologram are designed and experimentally demonstrated in the infrared regime, with the measured optical efficiency up to 84% (the simulated efficiency reaches 93%). Compared to previous metal-insulator-metal structures, this approach can realize higher efficiency and broader operating bandwidth owing to its lower ohmic loss. This design strategy is universal and can be easily scaled to any other spectra without complex optimization. Moreover, since metals have excellent mechanical and physical properties, such as good thermal and electrical conductivity, this all-metallic structure may provide a new thinking on interdisciplinary research. [ABSTRACT FROM AUTHOR]

Manipulating circularly polarized (CP) electromagnetic waves as desired is important for a wide range of applications ranging from chiral-molecule manipulations to optical communication, but conventional natural-materials-based devices suffer from bulky configuration and low efficiencies. Recently, Pancharatnam-Berry (PB) metasurfaces have demonstrated strong capabilities to control CP waves in different frequency domains. In this article, we present a concise review on PB metasurfaces for CP light manipulations, focusing mainly on the research works done by our own group. After briefly introducing the working principles of PB metasurfaces, we separately discuss how to construct high-efficiency PB metasurfaces in reflection and transmission geometries, and how to utilize them to control CP waves in different frequency domains, including meta-lensing, meta-hologram, and surface couplers. Finally, we conclude this review with our perspectives on future developments of PB metasurfaces. [ABSTRACT FROM AUTHOR]

Ion migration induced interfacial degradation is a detrimental factor for the stability of perovskite solar cells (PSCs) and hence requires special attention to address this issue for the development of efficient PSCs with improved stability. Here, an "S‐shaped, hook‐like" organic small molecule, naphthalene diimide derivative (NDI‐BN), is employed as a cathode interface layer (CIL) to tailor the [6,6]‐phenylC61‐butyric acid methylester (PCBM)/Ag interface in inverted PSCs. By realizing enhanced electron extraction capability via the incorporation of NDI‐BN, a peak power conversion efficiency of 21.32% is achieved. Capacitance–voltage measurements and X‐ray photoelectron spectroscopy analysis confirmed an obvious role of this new organic CIL in successfully blocking ionic diffusion pathways toward the Ag cathode, thereby preventing interfacial degradation and improving device stability. The molecular packing motif of NDI‐BN further unveils its densely packed structure with π–π stacking force which has the ability to effectually hinder ion migration. Furthermore, theoretical calculations reveal that intercalation of decomposed perovskite species into the NDI clusters is considerably more difficult compared with the PCBM counterparts. This substantial contrast between NDI‐BN and PCBM molecules in terms of their structures and packing fashion determines the different tendencies of ion migration and unveils the superior potential of NDI‐BN in curtailing interfacial degradation. [ABSTRACT FROM AUTHOR]

In contrast to traditional multilayer transmitarray designs, a novel dual-layer transmitarray antenna, consisting of two metallic layers printed on opposite sides of a single dielectric substrate, is proposed to achieve high transmission efficiency. First, it is theoretically derived that a dual-layer element, using the circular polarization conversion approach, can achieve a high transmission magnitude and a full transmission phase coverage. Next, a split-ring element has been designed as an example to demonstrate the theoretical analysis, where a full 360° transmission phase range with better than −1.0 dB transmission magnitude has been obtained. To experimentally validate the proposed concept and design, a circular transmitarray prototype is designed, simulated, fabricated, and tested at Ka-band. The diameter of the circular aperture is 405 mm ($27\lambda$), and the thickness of the transmission surface is 3.18 mm ($0.2\lambda$). The measured peak gain of the designed transmitarray is 36.1 dBic at 19.4 GHz with the aperture efficiency of 60.2%, while the measured 1 dB gain bandwidth is 9.5% (19.0–20.9 GHz). [ABSTRACT FROM AUTHOR]

This article presents a high data rate, high-efficiency 60-GHz on–off keying (OOK) CMOS transmitter and receiver. The transmitter consists of a voltage-controlled oscillator (VCO) and a modulator. The receiver consists of a low-noise amplifier, detector, and limiting amplifier (LA) and has a compact design. An analysis of the on–off isolation of the modulator and bandwidth of the LA reveals that the proposed transformer (TF) between the modulator and the VCO can improve the on–off isolation, and the feedforward capacitor can enhance the bandwidth. Implemented in the 65-nm CMOS technology, the transmitter and the receiver consume dc powers of 12.1 and 21 mW, respectively, at 12.5 Gb/s. Moreover, they occupy core chip areas of 0.09 and 0.06 mm2, respectively. The transceiver system is constructed with on-board Yagi–Uda antennas, and it achieves 12.5 Gb/s wireless OOK data transmission for a pseudorandom binary sequence of length 27 −1 with a bit error rate of less than 10−12. The proposed transceiver system achieves an energy efficiency of 2.65 pJ/bit. [ABSTRACT FROM AUTHOR]

An X‐band high‐efficiency GaN load modulated balanced amplifier monolithic microwave integrated circuit (MMIC) composed of 90° Lange Couplers at radio frequency (RF) input and output, a pair of balanced power amplifier (BPA) and a control signal (CS) PA is presented in this article. The impedance of the BPA is modulated by varying the amplitude and phase of the injected CS at same frequency. The prototype has a peak continuous wave output power of 42.5 dBm, with efficiency of 45% to 55% at peak power and 40% to 45% at 6 dB output back‐off over 8 to 11 GHz. The average efficiency for the 37.2 dBm output power is 40%, with adjacent channel leakage ratio of −32 dBc without digital predistortion at 10 GHz center frequency. [ABSTRACT FROM AUTHOR]

The disorderly distribution of defects in the perovskite or at the grain boundaries, surfaces, and interfaces, which seriously affect carrier transport through the formation of nonradiative recombination centers, hinders the further improvement on the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Several defect passivation strategies have been confirmed as an efficient approach for promoting the performance of PSCs. Herein, recent progress in the defect passivation toward efficient perovskite solar cells are summarized, and a classification of common passivation strategies that elaborate the mechanism according to the location of the defects and the type of passivation agent is presented. Finally, this review offers likely prospects for future trends in the development of passivation strategies. [ABSTRACT FROM AUTHOR]

A bio-based P–N synergistic flame retardant ammonium salt of d-Panthenol-tri (methylphosphonic acid) (ADPTMPA) was synthesized using a formaldehyde-free and solvent-free strategy for the highly efficient preparation of durable flame-retardant cotton. The ADPTMPA structure was verified by 1H NMR, 13C NMR and 31P NMR. FT-IR test revealed successful grafting of the flame retardant onto the cotton through P–O–C covalent bonding. The morphologies and structures of pure cotton and treated cotton were characterized by SEM and XRD, and the elemental compositions of cotton samples were analyzed by EDX. Volatile pyrolysis products of treated cotton were analyzed by TG-IR. Flame retardancy and washability of treated cotton were analyzed by limiting oxygen index (LOI) and vertical flammability tests (VFT). The LOIs of 40 wt% ADPTMPA treated cotton before and after 50 laundering cycles was determined as 46.5% and 35.8%, respectively. VFT showed the treated cotton exhibited no smoldering and continuous burning. All carbon lengths of treated cottons were less than 60 mm. The heat release rate and total heat release of treated cotton were decreased by 91.34% and 58.01% compared with pure cotton, respectively. There was 29.42 wt% carbon residual remaining when the treated cotton was exposed to heat flow of 35 kw/m2. The treated cotton exhibited excellent flame retardancy and washability. Additionally, the mechanical properties and whiteness of the treated cotton were well-maintained. [ABSTRACT FROM AUTHOR]

In this brief, analysis of class-F high-efficiency power amplifiers (PAs) when adding a second-harmonic input voltage to the gate node of the transistor is derived. The theoretical formulations of the drain current, output power, and drain efficiency are elaborated for this case. Based on them, the maximum output power and drain efficiency can be obtained from the closed-form solution set of the initial amplitude and phase of second-harmonic input voltage component. Calculations show that, with a proper second harmonic voltage adding to the input of the transistor, the performance of class-F PAs can be improved evidently. Besides, to validate the theoretical analysis, a simulation using a real GaN transistor has been presented. The relative errors of drain efficiency and output power between the results of theory and simulation are only 1.3% and 2.4%, respectively. To the best knowledge of the author, this is the first full theory to illustrate the performance enhancement of class-F PAs with a second-harmonic input voltage manipulation. [ABSTRACT FROM AUTHOR]

The principle hydrocarbon source in West Qaidam Basin, China, is the Xiaganchaigou formation, which charges a series of Cenozoic large reservoirs. We identified a series of organic-rich intervals within a sequence of Oligocene-age Xiaganchaigou evaporites in southwest Qaidam. By analyzing 2D and 3D seismic tomography and gamma ray well logs, we defined the distribution and extent of these source rocks. We also characterized their composition with trace element analysis and carbon and oxygen isotope measurements. Our data demonstrated distinctive characteristics of these source rocks with high salinity, abundant organic material, high hydrocarbon generation efficiency, and low maturity, which are associated with relatively rapid and productive hydrocarbon generation. Using high-pressure and high temperature experiments to simulate pyrolysis in samples of the source rocks, we investigated what enabled these young salt-rich source rocks to generate such an abundance of hydrocarbons. Our results highlighted the key role of saline and radioactive minerals in catalyzing accelerated pyrolysis of hydrocarbons during diagenesis and catagenesis. Salt catalysis clearly played an important role in hydrocarbon generation within lower maturity formations and also significantly improved and redefined the source rocks distribution and the extent of probable reserves in the southwest Qaidam. [ABSTRACT FROM AUTHOR]

• A Center-Tapped Medium Frequency Transformer (CT-MFT) design methodology is validated. • A high efficiency CT-MFT design is not found in any other previous proposal. • The CT-MFT design is intended to set upgrades in isolated DC-DC topologies. • The DC-DC SAB (Single Active Bridge) achieves 97 % efficiency integrating the CT-MFT. A design methodology for medium frequency transformers, which considers a central tap in its secondary winding, is thoroughly presented in this paper. Topologies such as SAB (Single-Active Bridge), PSFB (Phase Shift Full Bridge), and DAB (Dual Active Bridge) can be implemented using this type of transformer for nowadays applications. The design and implementation of a Central-Tapped Medium Frequency Transformer (CT-MFT) is carried out and it is tested as part of a SAB topology. Differently to other proposals, the equivalent model of the CT-MFT was thoroughly defined and verified in the simulation and a tailor-made design methodology is presented. As result, the CT-MFT prototype achieve 99.49 % efficiency which demonstrate the usefulness and efficacy of the proposed methodology. The experience gained in developing this advanced design procedure opens the possibility of further improving isolated unidirectional and bidirectional DC-DC converter topologies in aspects such as efficiency and reliability. [Display omitted] [ABSTRACT FROM AUTHOR]

High-efficiency laser diodes often adopt high mirror loss design to improve the external differential efficiency of the device. However, the significantly elevated threshold carrier density and exacerbated carrier thermal escape restrict the additional advancements in device performance. By replacing the 7 nm I n A l G a A s quantum well with an 11 nm G a A s P quantum well, there has been a considerable improvement in the differential gain. Furthermore, the higher conduction band offset has effectively inhibits the carrier thermal escape, which significantly improves the internal differential efficiency and temperature stability of the device. The stripe width of device was 150 μ m , and the cavity length was 2 mm. The device was tested under continuous wave current condition with the heat-sink temperature setting to 25 °C. The power conversion effectively is as high as 71% at 5.4 A. The slope efficiency and the threshold current were 1.47 W/A and 0.62 A. • Improvement of power conversion effectively of the laser diode at 780 nm is main target. • G a A s P material is used as a quantum well instead of I n A l G a A s quantum well. • The internal differential efficiency, absorption loss, threshold, and characteristic temperature have been greatly enhanced. • The power conversion efficiency of laser diode is significantly improved. [ABSTRACT FROM AUTHOR]

New experiments examine the interactions between a pair of three-dimensional (AR = 2) non-uniformly flexible pitching hydrofoils through force and efficiency measurements. It is discovered that the collective efficiency is improved when the follower foil has a nearly out-of-phase synchronization with the leader and is located directly downstream with an optimal streamwise spacing of X*=0.5. The collective efficiency is further improved when the follower operates with a nominal amplitude of motion that is 36% larger than the leader’s amplitude. A slight degradation in the collective efficiency was measured when the follower was slightly-staggered from the in-line arrangement where direct vortex impingement is expected. Operating at the optimal conditions, the measured collective efficiency and thrust are ηC=62% and CT,C=0.44, which are substantial improvements over the efficiency and thrust of ηC=29% and CT,C=0.16 of two fully-rigid foils in isolation. This demonstrates the promise of achieving high-efficiency with simple purely pitching mechanical systems and paves the way for the design of high-efficiency bio-inspired underwater vehicles.

Morphological control of all-polymer blends is quintessential yet challenging in fabricating high-performance organic solar cells. Recently, solid additives (SAs) have been approved to be capable in tuning the morphology of polymer: small-molecule blends improving the performance and stability of devices. Herein, three perhalogenated thiophenes, which are 3,4-dibromo-2,5-diiodothiophene (SA-T1), 2,5-dibromo-3,4-diiodothiophene (SA-T2), and 2,3-dibromo-4,5-diiodothiophene (SA-T3), were adopted as SAs to optimize the performance of all-polymer organic solar cells (APSCs). For the blend of PM6 and PY-IT, benefitting from the intermolecular interactions between perhalogenated thiophenes and polymers, the molecular packing properties could be finely regulated after introducing these SAs. In situ UV/Vis measurement revealed that these SAs could assist morphological character evolution in the all-polymer blend, leading to their optimal morphologies. Compared to the as-cast device of PM6 : PY-IT, all SA-treated binary devices displayed enhanced power conversion efficiencies of 17.4-18.3 % with obviously elevated short-circuit current densities and fill factors. To our knowledge, the PCE of 18.3 % for SA-T1-treated binary ranks the highest among all binary APSCs to date. Meanwhile, the universality of SA-T1 in other all-polymer blends is demonstrated with unanimously improved device performance. This work provide a new pathway in realizing high-performance APSCs., (© 2024 Wiley-VCH GmbH.)

Oxidation self-charging batteries have emerged with the demand for powering electronic devices around the clock. The low efficiency of self-charging has been the key challenge at present. Here, a more efficient autoxidation self-charging mechanism is realized by introducing hemoglobin (Hb) as a positive electrode additive in the polyaniline (PANI)-zinc battery system. The heme acts as a catalyst that reduces the energy barrier of the autoxidation reaction by regulating the charge and spin state of O 2 . To realize self-charging, the adsorbed O 2 molecules capture electrons of the reduced (discharged state) PANI, leading to the desorption of zinc ions and the oxidation of PANI to complete self-charging. The battery can discharge for 12 min (0.5 C) after 50 self-charging/discharge cycles, while there is nearly no discharge capacity in the absence of Hb. This biology-inspired electronic regulation strategy may inspire new ideas to boost the performance of self-charging batteries., Competing Interests: Competing interests statement:The authors declare no competing interest.

A formaldehyde-free reactive flame retardant, an ammonium salt of triethylenetetramine phosphoryl dimethyl ester phosphamide phosphoric acid (ATPEPDPA), was synthesized and characterized using nuclear magnetic resonance (NMR). Fourier transform infrared spectroscopy test (FT-IR), durability test and scanning electron microscopy (SEM) results suggested that ATPEPDPA was successfully grafted on cotton fabrics through a -N-P(=O)-O-C covalent bond. Moreover, the limiting oxygen index (LOI) value of 20 wt% ATPEPDPA-treated cotton was 44.6%, which met stringent washing standard after 50 laundering cycles (LCs). The high washing resistance of the ATPEPDPA-treated cotton was due to the p-π conjugation between the N atom and the P(=O) group in the flame-retardant molecule, which strengthened the stability of the -N-P(=O)-O-C bonds between ATPEPDPA and cellulose, and the -N-P(=O)-(O-CH 3 ) 2 groups in the ATPEPDPA. The cone calorimetric test showed that the treated cotton had excellent flame retardance. In addition, the TG and TG-IR tests suggested that ATPEPDPA performed a condensed flame retardance mechanism. Furthermore, the physical properties and hand feel of the treated cotton were well maintained. These results suggested that introducing -N-P(=O)-(O-CH 3 ) 2 and -N-P(=O)-(ONH 4 ) 2 groups into ATPEPDPA could significantly increase the fire resistance and durability of cotton fabrics.

A fractal metasurface-based ultra-broadband and high conversion efficiency reflective polarization rotator (PR) is proposed. The linearly y -/ x -polarized (LP) incident electromagnetic (EM) wave can be rotated over 90ºafter reflection by the proposed metasurface. The unit cell of the proposed PR is designed based on the fractal cut-wire resonator. Compared with a typical cut-wire resonator exciting three resonances, the fractal one can generate an extra resonant frequency. An ultra-broad bandwidth with a polarization conversion ratio greater than 0.9 (PCR>0.90) can be obtained from 8.00 to 23.00 GHz (a fractional bandwidth of 96.8%) at normal incidence, which is realized by the combination of the four resonances. The physical working mechanism and the polarization conversion performance of the metasurface are analyzed by surface current and E-field distributions, simulations and explained based on numerical calculations and plasmon resonance modes. Good agreement between the experiments and simulations is obtained. Compared with traditional PRs and other published metasurface-based PRs, the proposed metasurface can achieve an ultra-broad band and a high efficiency with a sub-wavelength size of the unit cell. The use of fractal topologies provides a novel and efficient method to further upgrade resonance characteristics in the design of PR, and the scalable geometry of the design shows its potential applications at optical, terahertz, and microwave frequencies. [ABSTRACT FROM AUTHOR]

• 2D LC/UHPSFC-Q-TOF-MS system was established for characterization. • GNPS was applied for dereplication with high efficiency and accuracy. • A mass of isomers were separated and exposed. • Two subclasses compounds were found for the first time. • Two new bufadienolides were identified to verify the strategy. Comprehensive analysis and identification of chemical components are very important to evaluate the efficacy and safety of traditional Chinese medicine (TCM). Meanwhile, the discovery of new natural compounds is of great significance for drug exploitation and development. Although two-dimensional liquid chromatography (2D LC) systems expand the peak capacity and improve selectivity and resolution, interpreting the post-processing data is tedious and time-consuming. In this study, an off-line two-dimensional liquid chromatography/ultra-high performance supercritical fluid chromatography tandem quadrupole time-of-flight mass spectrometry (2D LC/UHPSFC-Q-TOF/MS) system was established for systematic chromatographic separation and identification of bufadienolides. Subsequently, the Global Natural Product Social Molecular Networking (GNPS) was applied for dereplication of chemical components of adjacent fractions with high efficiency and accuracy. The key parameters which affected separation and detection with respect to chromatographic conditions and mass spectrometry conditions were optimized. The extract of Venenum Bufonis was fractionated into forty fractions by first-dimensional reversed phase high-performance liquid chromatography (HPLC), which were further analyzed by the second-dimensional UHPSFC-Q-TOF/MS in positive ion mode. The data of forty fractions was imported into GNPS and processed automatically within about five hours. Furthermore, the chemical components with similar featured fragments were classified into the same cluster, which was helpful for components identification. A total of 229 bufadienolides were characterized and two subclasses of compounds (bufogenins conjugated with carboxylic acid and N -heterocyclic bufogenins) were found in Venenum Bufonis for the first time. In addition, UHPSFC exhibited powerful separation ability of isomers in Venenum Bufonis. In this analysis, two new compounds were isolated and fully characterized by NMR verifying the feasibility of this combined analytical strategy. This integrated strategy can improve the efficiency in the detection of new compounds and offer greater observation of isomers from medicinal herbs and other natural sources. [ABSTRACT FROM AUTHOR]

In a direct modulation scheme and particularly in portable and wireless sensor network applications, the oscillator limits the transmitter efficiency therefore, the oscillator efficiency is critical and high-efficiency and high-power oscillators are increasingly required. This paper presents a high-efficiency and ultra-low-voltage power oscillator that operates at 2.4 GHz and is implemented in 65 nm CMOS technology. The power oscillator is a self-oscillating class-E power amplifier (PA) that utilizes a positive feedback system. A class-E PA is selected due to its high efficiency. The power oscillator has an optimized power consumption and output power, where a 2.4 mW power consumption is achieved under a 0.4 V power supply. The proposed oscillator demonstrates a maximum output power of - 0.45 dBm and a peak efficiency of 37.5%. The oscillator is tunable between 1.66 and 2.78 GHz. The oscillator is robust to a ± 15 % frequency deviation from a 2.44 GHz nominal frequency due to process, voltage, temperature variation. [ABSTRACT FROM AUTHOR]

Antimony selenide (Sb 2 Se 3) thin film solar cells have gained worldwide intense research owing to their suitable bandgap, high absorption coefficient, benign grain boundaries, earth-abundant element constituents and low fabrication cost. It is extremely important to investigate the interface passivation and minimize the carrier recombination to realize high-efficiency Sb 2 Se 3 solar cells. Very little is known, however, about the carrier recombination mechanisms at the interfaces of Sb 2 Se 3 solar cells. Herein, we show that a novel solution-processed SnO 2 layer (∼12 nm) incorporated into Sb 2 Se 3 thin film solar cells results in high power conversion efficiency of 7.5%, namely, an improvement of 39% relative to that of the solar cell without SnO 2 interfacial layer. Furthermore, the open-circuit voltage (V oc) is the highest ever reported for Sb 2 Se 3 solar cells. These improvements benefit from the better preferred [221] orientation, less bulk and interfacial defects in the Sb 2 Se 3 absorbers, and relatively ideal heterointerfaces due to the SnO 2 passivation. This work opens up new routes for the critical importance of interfacial control in Sb 2 Se 3 solar cells, which could be extended to other emerging low-dimensional thin film solar cells. Image 1 • A simple VTD technique is developed for the production of Sb 2 Se 3 absorbers. • Sb 2 Se 3 solar cell with a SnO 2 layer obtains high power conversion efficiency of 7.5%. • SnO 2 layer improves the properties of Sb 2 Se 3 absorbers. • An amorphous layer at interface is found, which can be inhibited by SnO 2 layers. [ABSTRACT FROM AUTHOR]

A dual-broadband and high-efficiency reflective linear polarization converter based on an anisotropic metasurface is presented. The device consists of two symmetrical, double-slotted metallic split-rings and one criss-cross structure, a dielectric layer, and a completely reflective metallic ground. The converter exhibits four resonances and can near-perfectly convert x- or y-polarized incident waves into cross-polarized waves in the frequency ranges of 9.38–13.36 GHz and 14.84–20.36 GHz. The polarization conversion ratios (PCRs) of the two bands are 98.21% and 99.32%, respectively. The energy conversion ratio (ECR) for energy loss measurement is almost 100% in these frequency bands. The polarization conversion principle is studied. The bandwidths and PCRs of the two bands are determined by varying the dielectric layer thickness. The simulation results are consistent with experimental observations. The designed dual-broadband and high-efficiency metasurface has great potential in the application of electromagnetic polarization control. [ABSTRACT FROM AUTHOR]

Abstract A new sky-blue thermally activated delayed fluorescent (TADF) emitter TRZ-DCF, has been developed based on 2-(9H-carbazol-9-yl)-7,7-dimethyl-5,7-dihydroindeno[2,1- b ]carbazole (DCF) as donor and 2,4-diphenyl-1,3,5-triazine as acceptor. Due to the fusion of fluorene and carbazole moieties into the single carbazole donor, the multimodified emitter exhibits obvious TADF characteristics with a smaller singlet-triplet splitting (Δ E ST) value of 0.22 eV and relatively high photoluminance quantum yield (PLQY) of 84%. As a result, a maximum external quantum efficiency (EQE) of 18.7%, a current efficiency (CE) of 39.0 cd A−1 and a power efficiency (PE) of 30.5 lm W−1 with a Commission Internationale de L' Eclairage (CIE) coordinates of (0.18, 0.34), significantly surpassing the performance of the reference emitter 9-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-9H-carbazole (TRTZ), are achieved in optimal device construction. It is found that the EQE roll-off (20.8%) of TRZ-DCF is acceptable, that the efficiency drops to 14.8% at 1000 cd m−2 in optimal device construction. These results demonstrate the multiple modifications of weak electron-donating carbazole donor is an effective way of constructing high-efficiency blue TADF emitters with small roll-off. Graphical abstract Image 1 Highlights • We present a new sky-blue thermally activated delayed fluorescence emitter combining a novel multimodified carbazole donor moiety with triazine-based unit for efficient organic light-emitting diodes. • The external quantum efficiency (18.7%), singlet-triplet splitting (0.22 eV) and photoluminance quantum yield (84%) as well as the roll-off behavior (20.8%) of the emitter TRZ-DCF have been finely tuned through multiple modification of the reference emitter TRTZ. [ABSTRACT FROM AUTHOR]

Graphical abstract Charge density difference of monolayer CN and Co-CN, blue and yellow represent the charge loss and accumulation, respectively (the isosurface value is set to 0.015e/A3). Highlights • The Co-CN photocatalyst was successfully synthesized and showed seductive catalytic activity. • The doped-Co make the rearrangement of the charge of Co-CN and lead to a excellent electronic structure. • The research results illuminate Co-doped can broaden light harvest, narrowed band gap, increased light absorption of Co-CN. Abstract Developing low-cost and high-efficiency g-C 3 N 4 (CN) semiconductor with modification has been proved to possess the potential advantage for environmental remediation in recent years. Herein, element doping of CN framework was found significantly on controlling its electronic structure. The new two-dimensional photocatalyst of Co-doped CN (Co-CN) applicable in photocatalytic reactions for 2-Mercaptobenzothiazole degradation was designed and synthesized. It was for the first time revealed that the Co-N bonding could lead to enhance significantly photoelectric properties, the rate for electron-hole pairs separation and photocatalytic activity in comparison with bulk CN. The characterization and density functional theory (DFT) results insight into the reason that the 3d electrons of the doped Co has excellent contribution to adjust the band gap of Co-CN. The present work provide a broadening window for Metal-doped CN with outstanding performance. [ABSTRACT FROM AUTHOR]

Highlights • A multi-scale method for modeling tunnel excavation in sand gravel strata is proposed. • A homogenization method for determining the mechanical properties of SRM is developed. • The multi-scale simulation method has a high efficiency without loosening accuracy. Abstract Sandy cobble stratum is a kind of heterogeneous geological body. A further study on the safety of wall rocks and underground structure demands developing suitable analysis method to simulate tunnel excavation in such a formation. Macro-scale simulations assume the sandy cobble soil to be homogeneous in numerical models. They get more efficient computing, but have difficulties in capturing enough information about the meso-scopic fields needed. Meso-scale simulations explicitly represent the individual components of the heterogeneous internal material structure in numerical models, e.g. the shape and the spatial distribution of rocks. They achieve high accuracy, but large computational cost would be needed. To reduce the numerical effort with the precision guaranteed, a multi-scale analysis method for simulating tunnel excavation in sandy cobble strata is proposed. In this method, the numerical model is divided into two regions, involving the meso-scale region and macro-scale region. The meso-scale region is a critical sub-domain disturbed by tunnel excavation, in it, the rocks and soil are considered as separate constituents. In the macro domain, the sand gravel soil was regarded as homogeneous materials whose effective material parameters were determined using an equivalent homogenization method. Three critical issues in the multi-scale method are explored, including: (i) the determination of meso domain and macro domain, (ii) the determination of rock maximum size that can be homogenized in the meso domain and iii) the determination of effective material parameters of soil-rock mixture during the equivalent process. By comparing with simulation results predicted by macro-scale and meso-scale simulation methods, the validation of the proposed multi-scale simulation method was carried out. The result indicates that the proposed multi-scale analysis method has a high efficiency without loosening accuracy on the simulation of tunnel excavation in sandy cobble stratum. [ABSTRACT FROM AUTHOR]

A high-power, high-efficiency, and high-speed white light-emitting-diode (LED) wireless transmitter is presented in this paper. This transmitter system consists of a gallium nitride field effect transistor (GaN FET) driver with push–pull structure, freewheeling circuit, and remaining carriers sweep-out circuit based on a phosphorescent white LED. A novel push–pull circuit structure with intensity modulation is used to increase the efficiency of the proposed transmitter to 94.2% at 12 Mb/s theoretical baud rate. Generally speaking, LED transmission speed is restricted by the remaining carriers in the junction capacitance. In this paper, we introduce an improved adjustable carrier sweep-out circuit to resolve this problem. High-frequency components in the signal are preemphasized by adding parallel freewheeling diodes between the drain and source of the GaN drivers. Test results show that the power efficiency is 93.17% with −3 dB bandwidth at 8.3 MHz. The results also show that the architecture proposed in this paper allows the baud rate of the transmitter to reach 10 Mb/s with bit error rate below 10 $^{-5}$ , which meets the IEEE 802.11 b requirements at distances farther than 1 m. [ABSTRACT FROM AUTHOR]