Double-sided Structure Research Articles

Carbazole-phenothiazine sensitizers boost tandem DSSC efficiency to 12.85 %

This study presents a significant advancement in tandem dye-sensitized solar cells (T-DSSCs) through the development of two carbazole-phenothiazine hybrid sensitizers, AEFH-1 and AEFH-2. AEFH-2, featuring a 4-carboxylcyanoacetamide acceptor group, thus achieving a remarkable power conversion efficiency (PCE) of 11.70 %, surpassing AEFH-1 (10.21 %) and the standard N719 dye (7.60 %). The superior performance of AEFH-2 is attributed to its optimized molecular design, which enhances the charge separation and electron injection efficiency. The incident photon-to-current efficiency (IPCE) of AEFH-2 reached 91.54 %, which was significantly higher than that of N719 (77.0 %) because of its strong electron-withdrawing groups and multiple anchoring functionalities, which improved TiO2 binding and charge transfer. Furthermore, an innovative double-sided parallel tandem DSSC (PT-DSSC) architecture was developed by integrating (N719 (top) and AEFH-2 (bottom)), resulting in a PCE of 12.85 %. This configuration exhibited exceptional photovoltaic parameters, including a Voc of 0.900 V, Jsc of 21.01 mA/cm2, and a fill factor of 67.95 %. The high IPCE of 97.50 % in the tandem setup was attributed to the complementary absorption profiles of N719 and AEFH-2, coupled with the light-trapping effect of the double-sided structure, enabling superior light harvesting and charge separation. Stability analysis further confirmed the durability of the tandem PT-DSSC, with performance maintained over 1000 h of continuous illumination, thus emphasizing its practical applicability. These findings underscore the potential of molecular engineering and architectural innovation to significantly enhance the efficiency and scalability of DSSCs, paving the way for high-performance, long-lasting solar energy devices.

A high-performance all-day vertical thermoelectric generator based on a double-sided reflective structure

Harvesting environmental energy sources is crucial for achieving renewable energy generation and net-zero emissions. However, ensuring uninterrupted electricity generation from environmental energy sources remains challenging. In this study, we present a simple, compact, and expandable all-day vertical passive thermoelectric generator (V-TEG) with a double-sided reflective structure that simultaneously harnesses solar and space cold energy. Outdoor experimental measurements, combined with finite element simulation analysis, revealed that the optimal angles of the solar reflector relative to the TEG range from 30° to 50°. Additionally, the TEG placed in the north–south orientation was found to enhance its daytime performance. The use of low-cost black paint combined with the solar reflector achieved equivalent spectral selectivity, effectively minimizing the infrared heat loss of the hot end of the TEG. During a 48-h outdoor test, the V-TEG achieved an average daytime power of 112.00 mW/m2 and a peak of 363.42 mW/m2. Comparative experiments demonstrated that the V-TEG outperformed horizontally placed TEG during the daytime. Furthermore, scaling the system by connecting three TEGs in series significantly increased the daily power output. This compact V- TEG system offers a promising solution for long-term power generation in low-power sensors and off-grid communities, supporting renewable energy and carbon neutrality goals.

The putative center in NGC 1052

Context: Many active galaxies harbor powerful relativistic jets, however, the detailed mechanisms of their formation and acceleration remain poorly understood. Aims: To investigate the area of jet acceleration and collimation with the highest available angular resolution, we study the innermost region of the bipolar jet in the nearby low-ionization nuclear emission-line region (LINER) galaxy NGC\,1052. Methods: We combined observations of NGC\,1052 taken with VLBA, GMVA, and EHT over one week in the spring of 2017. Our study is focused on the size and continuum spectrum of the innermost region containing the central engine and the footpoints of both jets. We employed a synchrotron-self absorption model to fit the continuum radio spectrum and we combined the size measurements from close to the central engine out to $ to study the jet collimation. Results: For the first time, NGC\,1052 was detected with the EHT, providing a size of the central region in-between both jet bases of $43\ perpendicular to the jet axes, corresponding to just around $250\,R_ S $ (Schwarzschild radii). This size estimate supports previous studies of the jets expansion profile which suggest two breaks of the profile at around $3 10^3\,R_ S $ and $1 10^4\,R_ S $ distances to the core. Furthermore, we estimated the magnetic field to be 1.25\,Gauss at a distance of $22\ from the central engine by fitting a synchrotron-self absorption spectrum to the innermost emission feature, which shows a spectral turn-over at $ 130\,$GHz. Assuming a purely poloidal magnetic field, this implies an upper limit on the magnetic field strength at the event horizon of $2.6 10^4\,$Gauss, which is consistent with previous measurements. Conclusions: The complex, low-brightness, double-sided jet structure in NGC\,1052 makes it a challenge to detect the source at millimeter (mm) wavelengths. However, our first EHT observations have demonstrated that detection is possible up to at least 230\,GHz. This study offers a glimpse through the dense surrounding torus and into the innermost central region, where the jets are formed. This has enabled us to finally resolve this region and provide improved constraints on its expansion and magnetic field strength.

Enhanced Mode Conversion and Out-of-Band Rejection in Double-Side Composite SSPPs Structure

Enhanced Mode Conversion and Out-of-Band Rejection in Double-Side Composite SSPPs Structure

Double-Sided Surface Structures with Undercuts on Cold-Rolled Steel Sheets for Interlocking in Hybrid Components

Double-Sided Surface Structures with Undercuts on Cold-Rolled Steel Sheets for Interlocking in Hybrid Components

Numerical calculation of air permeability of warp-knitted jacquard spacer shoe-upper materials based on CFD

Abstract In order to realize the rapid design of warp-knitted jacquard spacer shoe-upper materials and to explore the influence of different fabric surface organization structures on their air permeability, it is proposed to numerically simulate the air permeability performance of jacquard shoe-upper materials using ANSYS fluid analysis. First, four kinds of shoe material specimens with different upper and lower layer mesh alignment relationships are designed and tested, then the corresponding geometric structure models of the fabric are established based on the samples and appropriately processed, and finally the air permeability of the shoe material is numerically simulated and calculated based on computational fluid dynamics. The results show that, under the same conditions, the air permeability of double-sided mesh structure is significantly better than that of single-sided mesh structure, and its air permeability can be optimized by adjusting the relationship between the upper and lower layers of the fabric mesh; the airflow mainly passes through the fabric pores and gaps between the yarns, and the closer the fabric structure is, the more the air flow is hindered, and the worse the air permeability is. The simulation results of the established numerical model are consistent with the measured results, and the error is less than 10%, so it can be used to simulate and predict the air permeability of the warp-knitted jacquard spacer footwear materials, and provide theoretical support for the design and performance research of footwear materials.

Investigating Asymmetry Development from SiO to H2O Maser Regions in VX Sagittarii

Simultaneous very-long-baseline interferometry monitoring observations of H2O and SiO masers toward VX Sagittarii were conducted from 2014 February to 2019 January. Thirty epochs of observations revealed that the H2O and SiO masers had asymmetric and ring-like structures, respectively. However, from 2017 September to 2018 March, the SiO maser transformed from a ring-like structure to a northeast–southwest (NE–SW) extension, and the 43.1 and 86.2 GHz SiO maser components had velocities of 39.48 and 10.65 km s−1 in the NE–SW direction, suggesting a possible localized strong shock wave. The H2O maser had a double-sided structure oriented in the NE–SW direction with near-stellar velocity components, which aligned with the extended direction of the SiO maser. The nonregular optical brightness and maser intensity variations were speculated to be related to the morphological evolution of the SiO maser. During the stable states attained by regular pulsations, the SiO maser region was presumed to experience radial acceleration, which reverted the SiO maser to a ring-like structure. However, the H2O maser region, where the acceleration almost terminates, retained its asymmetric morphology due to the prior influence of external forces. The results suggest that substantial energy transfer can alter the dynamics of the SiO maser and surrounding atmosphere, leading to an asymmetric distribution in the H2O maser region.

Double-sided structure grating for dual-functional polarizing or non-polarizing splitter

In this paper, a novel bidirectional dual-functional metal-dielectric reflective grating with a double-sided structure is described, which can achieve transverse-electric (TE) polarization in the -1st order and transverse-magnetic (TM) polarization in the 0th order as a polarizing beam splitter in the upper part of the grating or TE and TM polarizations in the -1st order with polarization-independent property in the lower part of the grating. The proposed grating works at wavelength 1550 nm under Littrow mounting. Rigorous coupled-wave analysis (RCWA) is used to optimize grating parameters. The upper part can achieve diffraction efficiencies of 99.53% and 99.11% for TE polarization in the -1st order and TM polarization in the 0th order, respectively. In addition, the extinction ratios of -1st order and 0th order are 58.87 dB and 52.02 dB, respectively. The lower part can achieve diffraction efficiencies of 99.41% and 99.26% for TE and TM polarizations in the -1st order, respectively. Furthermore, wide incident wavelength and angular bandwidths can be obtained in both the upper and lower parts. Such a high-efficiency dual-functional grating has a wide range of applications in optical systems.

Constant-Voltage and Constant-Current Controls of the Inductive Power Transfer System for Electric Vehicles Based on Full-Bridge Synchronous Rectification

When an inductive power transfer (IPT) system conducts wireless charging for electric cars, the coupling coefficient between the coils is easily affected by fluctuations in the external environment. With frequent changes in the battery load impedance, it is difficult for the IPT system to achieve constant-voltage and constant-current (CVCC) controls. A CVCC control method is proposed for the IPT system that has a double-sided LCC compensation structure based on full-bridge synchronous rectification. The proposed method achieved good dynamic stability and was able to effectively switch between the output current and voltage of the system by adjusting only the duty cycle of the switch on the secondary side of the rectification bridge. As a result, the system efficiency was improved. The output characteristics of the double-sided LCC compensation structure was derived and the conduction condition with zero voltage was analyzed by using four switches through two conduction time series of the rectifier circuit. Then, the output voltage of the synchronized rectifier was derived. The hardware implementation of the full-bridge controllable rectifier was described in detail. Finally, a MATLAB/Simulink 2018a simulation model was developed and applied to an 11 kW prototype to analyze and validate the design. The results showed that the designed system had good CVCC output characteristics and could maintain constant output under certain coupling offsets. Compared with semi synchronous rectification methods, the proposed method had a higher efficiency, which was 95.6% at the rated load.

Highly Sensitive Iontronic Pressure Sensor with Side-by-Side Package Based on Alveoli and Arch Structure.

Flexible pressure sensors play a significant role in wearable devices and electronic skin. Iontronic pressure sensors with high sensitivity, wide measurement range, and high resolution can meet requirements. Based on the significant deformation characteristics of alveoli to improve compressibility, and the ability of the arch to disperse vertical pressure into horizontal thrust to increase contact area, a graded hollow ball arch (GHBA) microstructure is proposed, greatly improving sensitivity. The fabrication of GHBA ingeniously employs a double-sided structure. One side uses mold casting to create convex structures, while the other utilizes the evaporation of moisture during the curing process to form concave structures. At the same time, a novel side-by-side package structure is proposed, ensuring pressure on flexible substrate is maximally transferred to the GHBA microstructure. Within the range of 0.2Pa-300kPa, the iontronic pressure sensor achieves a maximum sensitivity of 10420.8kPa-1, pressure resolution of 0.1% under the pressure of 100kPa, and rapid response/recovery time of 40/35ms. In wearable devices, it is capable of monitoring dumbbell curl exercises and wirelessly correcting sitting positions. In electronic skin, it can non-contactly detect the location of the wind source and achieve object classification prediction when combined with the CNN model.

Ultrathin metasurface on a 100 nm-thick dielectric membrane absorbs infrared rays.

Flat optics based on metasurfaces produce unprecedented two-dimensional planar optical elements that cannot be developed with naturally occurring materials. However, it remains to be shown whether metasurfaces on ultrathin dielectric membranes can be adopted in a broad range of optical elements as flat optics. Here we demonstrate that a fabricated ultrathin metasurface composed of double-sided metal structures on a 100 nm-thick SiNx membrane absorbs infrared rays with a high absorptance of 97.1% at 50.1 THz. This ultrathin metasurface and its fabrication method would be a welcome contribution to a wide range of trailblazing applications, including ultrathin absorbers for imaging and light detection and ranging (LIDAR), directivity control of thermal radiation, and polarization control of vacuum ultraviolet light.

Thermoelectric performance of high aspect ratio double-sided silicon nanowire arrays

Roughly, 50% of primary energy worldwide is rejected as waste heat over a wide range of temperatures. Waste heat above 573 K has the highest Carnot potential (>50%) to be converted to electricity due to higher Carnot efficiency. Thermoelectric (TE) materials have gained significant attention as potential candidates for efficient thermal energy conversion devices. Silicon nanowires (SiNWs) are promising materials for TE devices due to their unique electrical and thermal properties. In this study, we report the successful fabrication of high-quality double-sided SiNW arrays using advanced techniques. We engineered the double-sided structure to increase the surface area and the number of TE junctions, enhancing TE energy conversion efficiency. We also employed non-agglomeration wire tip engineering to ensure uniformity of the SiNWs and designed effective Ohmic contacts to improve overall TE efficiency. Additionally, we post-doped the double-sided SiNW arrays to achieve high electrical conductivity. Our results showed a significant improvement in the TE performance of the SiNW array devices, with a maximum figure-of-merit (ZT) value of 0.24 at 700 K, fabricated from the single SiNW with ZT of 0.71 at 700 K in our previous work [Yang et al., Nat. Commun. 12(1), 3926(2021)].

Flexible capacitive pressure sensor with synergistic effect between double-sided pyramid sponge structure dielectric layer and fiber structure electrode layer

Flexible capacitive pressure sensors have a wide range of applications in wearable applications. This paper prepares a double-sided pyramidal foam sponge doped with barium titanate particles as the sensor dielectric layer by template method, and the flexible electrode layer prepared by electrostatic spinning technique. Benefiting from the excellent compressibility of the dielectric layer under stress and the good deformability of the electrode layer, the sensors with a synergistic effect between the electrode layer and the dielectric layer have been assembled. The sensor has high sensitivity (0.44 kPa−1) and a wide range (0–300 kPa), fast response (90 ms), ultra-low detection limit of 0.01 kPa, and reliable durability (>2000 cycles). The excellent performance of the sensor can realize the detection of human body signals and assembled into a data glove and combined with a host monitor to enable real-time monitoring of signal changes during grasping, and it shows enormous potential in intelligent wearable device applications.

Development of a multi-layered waterproof breathable fabric for full-weather apparel

In this research, a laminate was produced by assembling five textile layers. These layers were a coated double-sided knitted structure, a non-woven fabric, a hydrophilic membrane that was thermally assembled to a surface veil, and an open-work knitted fabric. The laminated textile's breathability, windproofness, and waterproofness were evaluated. The multi-layered fabric was windproof, and its water vapor permeability was 347.297 g?m-2?s-1 (CV= 8.902%). Its resistance to water penetration was equal to 117.68 Schmerber (CV = 7.81%). The assembled fabric's mechanical properties were also evaluated. Young?s modulus values were equal to 2 MPa (CV= 8.613%) and 1.6 MPa (CV= 8.349%) for both fabric directions. Its flexural rigidity was 5056.659 mg?cm and its surface total deformation was lower than 450 ?m when measured under 20, 40, 60, and 80 mN loads. Based on the results obtained, it was concluded that the developed multi-layered fabric could be used to produce raincoats and jackets to protect the wearer from light rain and drizzle.

Evaluating Earthquake Stability of Solar Module Soundproofing Structure by 3D Numerical Analysis

In this study, dynamic numerical analysis was conducted on the existing sound barrier wall structure and the recently developed double-sided solar-module-integrated sound barrier wall structure using the finite-difference method for numerical modeling. A seismic safety evaluation was performed based on a series of numerical analysis results. Both structures were modeled using a 3D modeling technique with FLAC 3D to account for differences in lateral stiffness. For seismic considerations, the Pohang seismic wave was selected to represent short-period earthquakes in line with Korea’s seismic characteristics. Additionally, the Hachinohe seismic wave was chosen to simulate long-period earthquakes and consider the effects of the seismic period. To calculate the input seismic waves based on the ground response, a site response analysis was conducted for a site designated for demonstrating a double-sided solar module-integrated sound barrier wall structure in Korea. The analysis reveals that the existing structure maintains overall structural integrity and ensures the safety of solar modules even in an earthquake with a return period of 2400 years. However, for a solar module-integrated sound barrier wall structure, stresses exceeding the compressive strength of the solar module occur in earthquakes with a return period exceeding 1000 years, necessitating additional design and reinforcement for preparation.

Double-sided numerical thermal modeling of fan-out panel-level MOSFET power modules

Double-sided packages for heat dissipation are an efficient thermal management mechanism for power semiconductor devices. A fan-out panel-level packaging (FOPLP), as one of the double-sided forms, exhibits excellent electro–thermal characteristics and provides low stray inductance and thermal resistance. Besides, the temperature at each point within the structure is closely related to its thermo–mechanical properties and device reliability. However, thermal resistance is limited in describing the temperature distribution. Finite element analysis (FEA) requires time-consuming construction of 3D models. Therefore, to depict the temperature distribution of FOPLP rapidly and accurately, a numerical heat transfer model was proposed for the double-sided package structure. The solution was obtained from the steady-state thermal balance Laplace equation using the separation of variables method. Several boundaries were analyzed to determine the specific parameters in the model. Finally, the temperature field predicted by the derived numerical model was compared with finite element simulation results. The proposed model was consistent with both Silicon (Si) and Silicon Carbide (SiC) FOPLP structures within the error of 15 % at the center of the device, which verified the validity and accuracy of the numerical model for double-sided heat dissipation. The proposed models and results could contribute to the development of effective thermal design tools for double-sided thermal power modules.

Kinematics and Collimation of the Two-sided Jets in NGC 4261: VLBI Study on Subparsec Scales

We report multifrequency VLBI studies of the subparsec scale structure of the two-sided jets in the nearby radio galaxy NGC 4261. Our analyses include new observations using the source frequency phase referencing technique with the Very Long Baseline Array at 44 and 88 GHz, as well as archival data at 15 and 43 GHz. Our results show an extended double-sided structure at 43/44 GHz and provide a clear image of the nuclear region at 88 GHz, showing a core size of ∼0.09 mas and a brightness temperature of ∼1.3 × 109 K. Proper motions are measured for the first time in the two-sided jets, with apparent speeds ranging from 0.31 ± 0.14 c to 0.59 ± 0.40 c in the approaching jet and 0.32 ± 0.14 c in the receding jet. The jet-to-counterjet brightness ratio allows us to constrain the viewing angle to between ∼54° and 84° and the intrinsic speed to between ∼0.30 c and 0.55 c. We confirm the parabolic shape of the upstream jet on both sides of the central engine, with a power-law index of 0.56 ± 0.07. Notably, the jet collimation is found to be already completed at subparsec scales, with a transition location of about 0.61 pc, which is significantly smaller than the Bondi radius of 99.2 pc. This behavior can be interpreted as the initial confinement of the jet by external pressure from either the geometrically thick, optically thin advection-dominated accretion flows or the disk wind launched from it. Alternatively, the shape transition may also be explained by the internal flow transition from a magnetically dominated to a particle-dominated regime.

Optimized Design of a Hexagonal Equal Gap Silicon Drift Detector with Arbitrary Surface Electric Field Spiral.

In our previous studies, the silicon drift detector (SDD) structure with a constant spiral ring cathode gap (g) and a given surface electric field has been partially investigated based on the physical model that gives an analytical solution to the integrals in the calculations. Those results show that the detector has excellent electrical characteristics with a very homogeneous carrier drift electric field. In order to cope with the implementation of the theoretical approach with a complete set of technical parameters, this paper performs different theoretical algorithms for the technical implementation of the detector performance using the Taylor expansion method to construct a model for cases where the parameter "j" is a non-integer, approximating the solution with finite terms. To verify the accuracy of this situation, we performed a simulation of the relevant electrical properties using the Sentaurus TCAD tool 2018. The electrical properties of the single and double-sided detectors are first compared, and then the effects of different equal gaps g (g = 10 μm, 20 μm, and 25 μm, respectively) on the electrical properties of the double-sided detectors are analyzed and demonstrated. By analyzing and comparing the electrical characteristics data from the simulation results, we can show that the double-sided structure has a larger transverse drift electric field, which improves the spatial position resolution as well as the response speed. The effect of the gap size on the electrical characteristics of the detector is also analyzed by analyzing three different gap bifacial detectors, and the results show that a 10 μm equal gap is the optimal design. Such results can be used in applications requiring large-area SDD, such as the pulsar X-ray autonomous navigation. in the future to provide navigation and positioning space services for spacecraft deep-space exploration.

Preparation of transparent anodic aluminum oxide films and their structural characteristics under thermal shock

Anodic aluminum oxide (AAO) films have a wide range of research and applications in the field of nanoscience and technology. Transparent AAO films require the oxide layer to be peeled off from the aluminum substrate to which it is attached, involving a complex preparation process and immersion in a variety of caustic solutions, resulting in the prepared AAO films that are very prone to fragmentation and unfavorable for applications. Here, we have prepared transparent AAO films by double-sided anodization method with secondary anodization, which consists of a double-sided porous structure spaced with a barrier layer. These transparent AAO films can be bent into bow shape and exhibit good toughness under the action of external forces applied at both ends. Then, the transparent AAO films were subjected to thermal shock experiments, and the changes in the microstructure of the AAO films before and after the thermal shock were analyzed. The relationship between the microstructure of the AAO films and the good toughness they exhibit was also investigated.

A dual-band low-profile Fabry–Perot resonator antenna with single partially reflecting surface

ABSTRACTThis paper presents a novel design for a low-profile Fabry–Perot resonator antenna (FPRA) that operates at two distinct frequency bands using a single partially reflecting surface (PRS). The PRS is composed of two different types of unit cells arranged in a staggered fashion. These unit cells are comprised of double-sided complementary structures, including a square patch with a square aperture and a circular ring with a circular ring slot. To reduce the overall profile of the antenna, an artificial magnetic conductor (AMC) surface is utilized as the reflection plane. The proposed design employs a dual-band slotted patch antenna as the primary source. The overall dimensions of the FPRA are 91 mm×91 mm×5.54 mm. The performance of the prototype antenna is validated through measurement, demonstrating peak gains of 14.1 and 16.1 dBi at frequencies of 6.65 and 12.05 GHz, respectively. Additionally, the antenna exhibits −10 dB impedance bandwidths of 6.5–6.8 GHz and 12.15–12.23 GHz at the two frequency bands.