Suitable Thickness Research Articles

Optimization of temperature distribution in building envelopes of Ahmedabad region using nano-encapsulated phase change material

The incorporation of Phase Change Materials (PCM) into the building envelopes helps to increase indoor thermal comfort while lowering energy usage. The selection of PCM is directly related to its performance and might be viewed as an optimization challenge. The manuscript highlights the optimization of temperature distribution in building envelopes (walls and roofs) of Ahmedabad by choosing the suitable PCM and Nano-particle. Three different PCMs (RT31, RT 35, and RT42) and Nano-particles (Al2O3, CuO, and ZnO) with different concentrations (12 %, 16 %, and 20 %) are considered for the optimization. The PCMs are encapsulated into the building layer thickness to examine their characteristics like effective thermal conductivity, concentration, melting point, etc. These parameters are evaluated in a room that measures 5 m x 4 m x 3.5 m (L x W x H). The design-builder software (Version 7.0.2.006) is used to carry out the steady-state numerical simulations for this building envelope. The results suggest that the integration of PCM reduces the building's overall energy consumption by 7.92 kWh/m2 per year. The optimal design is proposed by establishing a temperature difference (ΔT) in building envelopes and utilizing a hybrid optimization technique (a combination of Artificial neural network (ANN) and Genetic algorithm (GA)). This temperature difference of the building envelope is confirmed to be dependent on their PCM melting point, effective thermal conductivity, concentration (in%), and PCM layer thickness. Hybrid optimization is found to be the most stable strategy for predicting temperature dilation and energy storage in building envelopes. Thus this paper gives a systematic understanding of the selection of PCM and Nano-particles and identifies the suitable PCM layer thickness for encapsulation.

Optimizing skyrmionium movement and stability via stray magnetic fields in trilayer nanowire constructs.

Skyrmioniums, known for their unique transport and regulatory properties, are emerging as potential cornerstones for future data storage systems. However, the stability of skyrmionium movement faces considerable challenges due to the skyrmion Hall effect, which is induced by deformation. In response, our research introduces an innovative solution: we utilized micro-magnetic simulations to create a sandwiched trilayer nanowire structure augmented with a stray magnetic field. This combination effectively guides the skyrmionium within the ferromagnetic (FM) layer. Our empirical investigations reveal that the use of a stray magnetic field not only reduces the size of the skyrmionium but also amplifies its stability. This dual-effect proficiently mitigates the deformation of skyrmionium movement and boosts their thermal stability. We find these positive outcomes are most pronounced at a particular intensity of the stray magnetic field. Importantly, the required stray magnetic field can be generated using a heavy metal (HM1) layer of suitable thickness, rendering the practical application of this approach plausible in real-world experiments. Additionally, we analyze the functioning mechanism based on the Landau-Lifshitz-Gilbert (LLG) equation and energy variation. We also develop a deep spiking neural network (DSNN), which achieves a remarkable recognition accuracy of 97%. This achievement is realized through supervised learning via the spike timing dependent plasticity rule (STDP), considering the nanostructure as an artificial synapse device that corresponds to the electrical properties of the nanostructure. In conclusion, our study provides invaluable insights for the design of innovative information storage devices utilizing skyrmionium technology. By tackling the issues presented by the skyrmion Hall effect, we outline a feasible route for the practical application of this advanced technology. Our research, therefore, serves as a robust platform for continued investigations in this field.

Influence of Composition and Thickness on The Color and Translucency of Glass-Ceramic Materials for Laminate Veneer Restorations: An In Vitro study

Statement of the problem: Numerous glass-ceramic materials are commercially available, yet achieving optimal esthetic results relies significantly on material composition and thickness. The selection of suitable material and thickness poses an ongoing challenge in clinical practice. Objective: This study aimed to investigate the effect of the composition and thickness of different glass-ceramic materials on the Commission Internationale de l'éclairage (CIE) L*, a*, and b* color coordinates and the translucency parameter (TP00). Materials & Methods: Glass-ceramic blocks of A2 shade, with low translucency, encompassing feldspathic (FS), leucite-reinforced feldspathic (LR), and lithium-disilicate (LD) compositions, were sectioned into three thicknesses: 0.5 mm, 0.7 mm, and 1 mm (n=10). All specimens were polished with ceramic polishing rubbers. Using a spectrophotometer, the CIE L*, a*, and b* color coordinates of the specimens were measured over gray, white, and black backgrounds. The TP00 was calculated using the CIEDE2000 color difference formula. The CIE L*, a*, b*, and TP00 were analyzed using two-way ANOVA and Tukey HSD post-hoc tests (α=0.05). Results: Material, thickness, and their interaction significantly influenced the CIE L*, a*, b*, and TP00 values (P<0.001). The LR group displayed the highest L* and a* values, while the LD group showed the lowest (P<0.001). Conversely, the LD group exhibited the highest b* value (P<0.001). Lightness was lowest in 0.5 mm-thick specimens (P<0.001) and similar for 0.7 mm-thick and 1.0 mm-thick specimens (P>0.05). Redness and yellowness increased with increasing thickness (P<0.001). Regardless of thickness, the FS group had the highest TP00 (16.32±1.54), while the LR group had the lowest TP00 (14.31±1.67). Regardless of material, 0.5 mm-thick specimens demonstrated significantly higher TP00 (17.49±1.10) than 0.7 mm-thick (15.45±0.83) and 1.0 mm-thick (13.11±1.12) specimens. There was no significant difference between the 0.5 mm-thick FS and LD groups (P>0.05) and 1.0 mm-thick LR and LD groups (P>0.05). Conclusions: Even when sharing the same shade, glass ceramics may exhibit varying color and translucency properties due to their distinct chemical compositions and thicknesses.

Pseudocapacitance PPy coating modulation on the nano-MnO2 surface to improve zinc storage ability in neutral fiber battery

With the rapid development of wearable electronic technology, the research of fiber energy storage batteries, such as fiber Zn-MnO2 batteries, has also been promoted. However, mechanically mixing conductive carbon and MnO2 to improve charge transfer efficiency is still considered inefficient. In this work, PPy was used to coat the surface of nano MnO2. By regulating the structure of C-MnO2, an excellent charge transfer efficiency C-L27-MnO2 material with a suitable thickness and uniform PPy film was obtained. When the C-L27-MnO2 material was applied to a neutral fiber zinc-ion battery, it showed a significantly improved cycle and rate capacity. At a current density of 10 mA g−1, the specific capacity of the MnO2 electrode increased from 124.2 mAh/g to 316.0 mAh/g.

Improvement of Charge/Discharge Performance of Li Metal Battery Using Ionic Liquid Electrolyte with 3DOM PI Separator

Ionic liquid electrolytes (ILEs) have attracted attention as promising electrolyte candidates. ILEs can realize non-flammable rechargeable batteries. In addition, other advantages of ILEs are negligible volatility and high thermal stability. These properties can improve the safety of Li metal batteries. However, conventional polyolefin separators cannot be used due to low affinity with highly viscos electrolytes such as highly concentrated electrolytes and ILEs. So far, glass filters with thicknesses of several hundred micrometers have been used as alternatives. However, it is too thick to realize a real cell. Furthermore, the glass filter shows low reversibility of Li deposition/dissolution due to its non-uniform pore structure. It is known that Li deposition/dissolution sometime results in an internal short circuit which is caused by inhomogeneous Li deposition. The separator has a large effect on the uniformity of Li deposition/dissolution behavior. Therefore, new separators with good properties, such as high affinity with electrolyte, hightypemechanical strength, suitable thickness and excellent reversibility of Li deposition/dissolution are strongly required. So far, we have developed a three-dimensionally ordered macroporous polyimide (3DOM PI) memblane with a thickness of 30 micrometers as a separator having a good affinity with ILEs. In this study, we improved the performance of Li metal batteries by using both ILEs and 3DOM PI separator. Three types of separators were used in this study; glass filter (Whatman, GF/A, 260 μm), surfactant coated polypropylene (PP) (25 μm) and 3DOM PI separator (30 μm). 3DOM PI separator was prepared by using a colloidal template method. Lithium bis(fluorosulfonyl)imide and N-metyl-N-Propylpyrrolidinium bis(fluorosulfonyl)imide mixture with a molar ratio 1:1 was used as the ILE. Li deposition/dissolution was carried out by using Li symmetric cell with three types of separators and the ILE, in order to investigate the Li deposition/dissolution behavior. The Li deposition/dissolution capacities for all tests were 1 mA h cm-2. Fig. 1 shows the voltage profiles during the Li deposition/dissolution using different current densities. In the case of the 3DOM PI separator, the stable Li deposition/dissolution behavior was observed up to the current density of 3.0 mA cm-2. In the case of the surfactant coated PP separator, the applicable maximum current density was 1.5 mA cm-2. In the case of the glass filter, an internal short circuit was observed even at lower current density. The Li deposition/dissolution behavior strongly depends on the types of separators, and the 3DOM PI separator provides most stable Li deposition/dissolution, especially at high current density. Fig. 2 shows the voltage profiles during the Li deposition/dissolution cycles at the current density of 1 mA cm-2. In the case of the 3DOM PI separator, the highly stable Li deposition/dissolution was observed over 150 cycles. In contrast, in the case of the surfactant coated PP separator, unstable Li deposition/dissolution was observed after the 50th cycle, probably due to micro-short circuit. In the case of the glass filter, the internal short circuit was more clearly observed at the initial cycles. From the above results, it is confirmed that the 3DOM PI separator can provide stable Li deposition/dissolution behavior. This is due to the uniform structure of the 3DOM PI separator and high stability of ILE. Figure 1

Thermal performance of a solar heat collection and storage wall with night insulation in winter: A numerical study

The application of phase change material (PCM) in Trombe walls (TW) can improve all-day indoor thermal comfort. However, the heat loss via the glass is relatively large, resulting in low thermal efficiency at night. This paper designs a double glass and a thermal insulation curtain used to increase the thermal efficiency of a TW with PCM at night. In addition, a mathematical model based on the implicit difference method was established to study the thermal efficiency and heat loss of the proposed wall in Beijing. The findings indicate that the thermal efficiency at night is improved by 16.23 % compared to a traditional TW, while heat loss at night drops by 7.75 %. The heat gain at night first increased and then decreased with the augment of phase change temperature. As the latent heat or thermal conductivity of PCM increases, the heat gain declines during the day and increases during the night. The most suitable thickness of PCM is 0.02 m. The farther the insulation curtain is from the inner glass, the greater the heat loss and the smaller the indoor heat gain at night. And the later the opening time of the air vents during the day, the smaller the heat gain during the day and the greater the heat loss. But the resulting increase in nighttime heat gain is not significant. This study can offer design suggestions for enhancing indoor thermal comfort and nighttime insulation performance.

#340 : Autologous Platelet-Rich Plasma (PRP) Treatment for Thin Endometrium in Yasmin IVF Clinic RSCM

Background and Aims: PRP is a biological product defined as a portion of the plasma fraction of autologous blood with a platelet concentration above the baseline. PRP is one of the trends in regenerative medicine and also being used in reproductive medicine area, one of which is to treat thin endometrial problems by infused intrauterine. The goal of this treatment is to reach suitable endometrial thickness by enhancing proliferation of endometrial cells. A good and receptive endometrium is necessary to achieve successful embryo implantation, both in natural pregnancy and assisted reproductive technology. This study aimed to analyze the outcome of PRP treatment during 2022 in Yasmin IVF Clinic RSCM. Method: This is a retrospective study which collected PRP service data during 2022 in Yasmin IVF Clinic RSCM. 76 subjects underwent PRP intrauterine infusion with thin endometrium indication ([Formula: see text]6 mm). Subjects were then categorized into two groups, first only underwent PRP procedure once and another group underwent intrauterine PRP procedure two times. Subjects underwent intrauterine PRP procedure more than two times were excluded from this study. All data were then statistically analyzed. Results: 76 subjects underwent intrauterine PRP infusion in Yasmin IVF Clinic RSCM during 2022. All subjects were diagnosed with thin endometrium ([Formula: see text]6 mm). Only 23 subjects underwent one intrauterine PRP procedure based on endometrial thickness assessment. The rest of the subjects, 53 patients underwent intrauterine PRP infusion two times. After PRP infusion, the endometrium thickness in PRP group was 8.37 ±0.22 mm, which was significantly thicker than that in control group (6.05 ±0.23 mm) (P [Formula: see text]0.05). However, implantation rate and clinical pregnancy rate in PRP group were not significantly higher than those in control group (28% vs 9%; 37% vs 20%; P [Formula: see text]0.05; respectively). Conclusion: Intrauterine PRP infusion seemed to be a good option in facing thin endometrium diagnosis. It is able to enhance endometrial thickness. However, the result of clinical pregnancy still needs to be improved.

Amphoteric polyelectrolyte ultrafiltration membranes with high permeability property via in-situ modified by PES-N and PES-COOH

Ultrafiltration membrane is one of the most commonly used separation materials for wastewater treatment, due to its low operating pressure, high flux and large specific surface area. In this work, we utilized PES polymer as a polymer precursor to prepare a series of amphoteric polyelectrolyte membrane with different content of amphoteric polyelectrolyte group via simple polymer blending processes. The amphoteric polyelectrolyte groups in amphoteric polyelectrolyte membrane could effectively regulate the retention ability and significantly improve the water flux of membrane. The amphoteric polyelectrolyte membrane with the content ratio of 4:6 (PES-N/PES-COOH) exhibited the highest water flux of 467 Lm−2 h−1 and BSA retention factor of 94.2% than that of other ultrafiltration membranes owning to the abundant porosity and suitable thickness of the top layer. Moreover, the results of static BSA adsorption and flux recovery ratio also proved that the amphoteric polyelectrolyte membrane have a good BSA rejection and antifouling performance. Therefore, these results reveal a simple synthesis and design strategy for constructing the high-performance amphoteric polyelectrolyte membrane for water treatment and provide theoretical and technical guidance for water treatment process based on membrane technology.

Investigating the influence of absorber layer thickness on the performance of perovskite solar cells: A combined simulation and impedance spectroscopy study

Absorber thickness is one among keys parameters that can have significant effects on the performance of the solar cell. An appropriate absorber thickness should be chosen to optimize the performance of the cell.The main objective of this work is to offer a perovskite solar cell with high efficiency using a suitable thickness of the active layer. Therefore, this study focuses on the optimization of the solar cell thickness, which can also be achieved by using simulation with SCAPS-1D, to predict the performance of the cell at different thicknesses. In this case, the four main parameters; the short circuit current density, the open-circuit voltage, fill factor and power of conversion efficiency, were extracted and analyzed from I–V characteristics at different thicknesses. In addition, the complex impedance data were also generated by using simulation with SCAPS-1D. To the best of our knowledge, this approach was not used before for many works carried out by SCAPS-1D simulation; where these studies were limited to I-V characteristics. This novel approach to investigating the electrical response of this solar cell concerning thickness involves the integration of complex impedance and modulus functions. This integration enables us to discern the respective contributions of ionic diffusion and recombination processes, through our deconvolution procedure, the results obtained indicate the absorber layer thickness increases, the diffusion and recombination processes are affected differently, subsequently influencing the overall performance of the solar cell. Both methodologies employed in this study consistently identified the maximum efficiency at an optimal thickness of 700 nm.

Mechanical properties and failure patterns of sandwich panels with AR-glass textile reinforced concrete face sheets subjected to quasi-static load

A sandwich panel was prepared with Alkali Resistant-glass textile reinforced concrete (ARG-TRC) as the face sheet and Expanded Polystyrene (EPS) granular mortar as the core in this paper. Afterward, a quasi-static bending test was conducted to investigate the influences of the number of reinforcement layer, core thickness, and interface rib on the bending behaviors and failure of ARG-TRC sandwich panels (ARG-TRC-SPs). On this basis, the elastic bending deformation and ultimate bending capacity were theoretically predicted, and the failure mechanism was analyzed. The results show that ARG-TRC-SPs exhibited three common failure modes: face sheet bending fracture, core shear, and core crushing. Increasing the reinforcement layers significantly improved the properties of ARG-TRC-SPs but decreased textile utilization. Although the enhancement of the interface rib was dependent on the number of reinforcement layers, it could improve the integrity of ARG-TRC-SPs. There was a suitable core thickness for the ARG-TRC-SPs, and a thicker core did not indicate better mechanical properties. The theoretically predicted elastic deformation and ultimate bending capacity were in good agreement with the test results. However, the contribution of the core and interface ribs was underestimated. These results can provide a valuable reference for researchers and engineers in designing and applying TRC-SPs.

On the process of fine sediment infiltration into static gravel bed: A CFD–DEM modelling perspective

AbstractThe gravel bed clogging, caused by infiltration and accumulation of fine sediment, degrades the river ecology. A proper understanding of the infiltration process, and underlying mechanism and causes, are necessary to take preventive measures. The process of fine sediment infiltration into static gravel bed is studied by distinguishing between bridging and percolation behaviours, as they affect the river ecology and physical processes occurring in the river system differently. However, several contradicting observations, concerning their occurrences, are reported. We employed the unresolved CFD–DEM method to simulate and investigate the infiltration process. The theoretical size ratios, corresponding to different geometrical configurations for a binary mixture of mono‐disperse spherical particles, representing bridging and percolation processes, are considered and simulated with and without flowing water effects. The effects of several turbulence models on the infiltration process are also studied. We found that fine sediment infiltration in fluvial deposits is mainly gravity‐dominated, supporting Cui's hypothesis that fine sediment infiltration through intra‐gravel flow is similar to fine sediment infiltration driven by gravity. In contrast to consensus in the field, our results demonstrate that the occurrences of different infiltration processes (bridging and percolation) seem to be independent of gravel bed thickness, rather depend only on the relative grain size distribution of fine sediment and gravel. However, a precise definition of a ‘thick enough’ gravel bed is necessary to distinguish between bridging and percolation behaviours. Here, we hypothesize a suitable gravel bed thickness, which might be regarded as a ‘thick enough’ gravel bed.

Preparation and properties of copper-aluminum composite strips and foils by horizontal continuous composite casting and rolling

Cu-Al composite strips and foils show broad application prospects in electric power, new energy and other fields. However, they are difficult to prepare because of brittle interfacial intermetallic compounds and deformation ability difference between two matrix metals. In this study, Cu-Al composite strips and foils with the thickness of 350 µm and 50 µm are successfully prepared by horizontal continuous composite casting and rolling. Moreover, the effects of as-cast interfacial layer thickness on the properties of Cu-Al composite strips are studied. In the rolling, the as-cast interfacial layer is broken into fragments, so as to promote the Cu-Al matrix bonding at atomic scale. The local solid-state amorphous transformation is also observed at the newly formed Cu-Al interface. Therefore, with the as-cast interfacial layer thickness decreasing from 400 µm to 25 µm, the peeling strength of Cu-Al composite strips increasing from 15.1 N/mm to 17.5 N/mm. With the as-cast interfacial layer thickness decreasing from 400 µm to 65 µm, the conductivity of Cu-Al composite strips increases from 62.36%IACS to 72.58%IACS because the size of interfacial layer fragments is reduced. However, with the as-cast interfacial layer thickness decreasing from 65 µm to 25 µm, the conductivity decreases from 72.58%IACS to 68.65%IACS because the copper layer thickness after rolling is reduced. Large interfacial layer fragments hinder current conduction, but a suitable interfacial layer thickness can inhibit the coordinated deformation of Cu and Al, so as to increase the proportion of copper layer thickness in the entire composite strip.

Performance Analysis of SnO2/CsSnGeI3/CuSCN perovskite solar cells using SCAPS 1D Simulator

In this paper, we have used Cesium tin-germanium triiodide (CsSnGeI3) perovskite-based solar cells (PSC). Here, SnO2 and CuSCN have been used as electron transport and hole transport layers, respectively. We have optimized the performance parameters of this device using an open-source software known as Solar cell capacitance simulator (SCAPS–1D). We have varied the thickness of absorber layer to understand its impact on the efficiency of the proposed solar cell. We have also varied the interface defects and defect density of absorber layer to optimize the performance of this device. Further, we have also varied the thickness of ETL and HTL with respect to absorber layer to determine the best suitable thickness of all the layers. Later, we have varied the electron affinity of ETL layer to determine the most suitable value. Finally, we have varied the work function of the back metal contact to understand its influence on the efficiency of the solar cell. The analysis indicates that the highest obtained efficiency of this device is 31.97% and the observed open circuit voltage and fill factor is 1.25 V and 89.97%, respectively.

Passivating surface states of graphitic carbon nitride for improved photocatalytic Fenton-like decontamination

Graphitic carbon nitride (g-C3N4) is a promising photocatalyst for peroxymonosulfate (PMS) activation towards water treatment, but its inherent surface defects always lead to serious recombination wasting charge carriers. Herein, we constructed cobalt doped aluminum oxide overlayer (AlOx-Co) on g-C3N4 nanosheets, passivating surface states for accelerated photocatalytic PMS activation. The AlOx coating prevents dangling bonds associated with surface recombination, and the Co doping reduces dynamic barrier. Thus, g-C3N4/AlOx-Co (0.0745 min−1) exhibits a 3.5 times higher activity than bare g-C3N4 (0.0168 min−1) towards iohexol degradation. Systemic spectroscopic and photoelectrochemical measurements reveal that AlOx-Co overlayer could weaken in-band recombination and relieve Fermi level pinning, which facilitate the charge transfer. Meanwhile, this overlayer has suitable thickness (3 ∼ 5 nm) for feasible tunneling effects to generate surface-bound radicals. Our work attempts to overcome inefficient surface charge separation and transfer simultaneously for improved contaminant removal via photocatalytic Fenton-like catalysis.

Solvent assisted to prepare shell structured Cu/γ-Al2O3 catalyst with low Cu content for oil efficient hydrodeoxygenation to high-quality biofuel

Using biomass “green carbon” can effectively alleviate the energy crisis and environmental protection problems. To achieve efficient removal of oxygen atoms, retain complete carbon chain structures, and maximize the economy of carbon atoms for the inedible or waste bio-oils, a novel and unique shell-style Cu/γ-Al2O3 catalyst with low Cu content was developed to solve the current problems including easy sintering and poor hydrodeoxygenation (HDO) activity of the studied catalysts. The shell Cu/γ-Al2O3 catalyst (Cu-CPA) with the Cu content of 3 wt% prepared by acetone as solvent has excellent cycle-stable HDO performances, the methyl laurate hydrogen conversion and C12 alkanes selectivity were 87.2 and 80.0 % at 400 °C, respectively, which were equivalent to the activities of the ordinary 10 wt% Cu/γ-Al2O3 catalyst prepared by wet impregnation using water as a solvent. The polarity of the impregnating solution modulates the shell layer thickness of the Cu-based catalysts to improve the surface chemical composition and pore structure of the catalysts, which in turn affects the lipids HDO performances of the corresponding catalyst. Active heterogeneous shell Cu-CPA catalyst showed high activity, selectivity, and stability in HDO, which can be attributed to the unique structure with suitable active shell thickness and high utilization rate of the metal Cu active components. This study provides feasible ideas for the preparation of shell-type catalysts, the design of anti-sintering Cu-based catalysts, and the production of renewable biofuels.

Evaluating the impacts of fin structures and fin counts on photovoltaic panels integrated with phase change material

Metal fins synergized with phase change materials (PCMs) provide good thermal management for photovoltaic (PV) panels, and the performances largely depend on the shapes and counts of the fins, and the layouts of the cavity. This work first compares the thermal behaviors of one fractal fin or one straight fin in the cavity with height H (mm)-width W (mm) of 80-75, 100-60, 120-50, 150-40, and 200-30, respectively. The results show that one fractal fin can accelerate the PCM melting and further lower the PV temperature by 2 °C than one straight fin. Moreover, a more desirable cavity with the dimension of 120-50 is clarified by comparing the PV panels average efficiency during 0∼180 min versus the energy input. Next, comparisons of the fin counts N = 1, 2, 3, and 4 reveal that raising the fin count N to 2 reduces the PV panel temperature by 2.3 °C, and the fin counts cause most of the difference. Ultimately, a suitable PCM thickness of 40 mm is selected by considering the PV panel temperature along with the weight and cost of the systems. This study aims to promote the development of finned PV panels integrated with PCMs.

Eliminating Ferroelectric Hysteresis in All-Two-Dimensional Gate-Stack Negative-Capacitance Transistors.

Boltzmann distribution thermal tails of carriers restrain the subthreshold swing (SS) of field-effect transistors (FETs) to be lower than 60 mV/decade at room temperature, which restrains the reduction of operate-voltage and power consumption of transistors. The negative-capacitance FET (NC FET) is expected to break through this physical limit and obtain a steep SS by amplifying the gate voltage through the negative capacitance effect of the ferroelectric thin film, providing a new way to further reduce the power consumption of the transistor at the end of Moore's law. Here, we show a MoS2 NC FET with a CuInP2S6 ferroelectric, exhibiting a large on/off ratio of 108, a steep SS as low as 6 mV/decade, and a wide sub-60 mV/decade drain current range of more than 4 orders of magnitude while sacrificially inducing a huge hysteresis larger than 500 mV. Furthermore, we found that by inserting the h-phase boron nitride (h-BN) layer with suitable thickness, the dielectric capacitance matches the ferroelectric negative capacitance better, and thus the hysteresis on the transfer curve is reduced, and the ideal switching-behavior transistors with SS as low as 62 mV/decade and only 5 mV negligible hysteresis were obtained. Our work demonstrates that under the capacitance-matching condition, the hysteresis-free negative-capacitance transistors do not act as the predicted steep-slope transistors, but their voltage-saving still occurs instead as a type of effective transconductance booster with more than 20 times transconductance amplification.

Energy-absorption analyses of grooved Al-sheet stacks using modified split Hopkinson pressure bar

This study suggests that stacks of thin aluminum (Al) sheets with fine rectangular or triangular grooves are effective materials for energy absorption. The energy-absorbing performance of these materials was evaluated using a modified split Hopkinson pressure bar (SHPB). Two important energy-absorbing parameters, impact momentum (I) and maximum impact acceleration (amax), were measured from stress-time (σ-t) curves. These parameters were found to vary with groove shape, groove cavity fraction, and specimen thickness. Both I and amax showed a continuous decrease as the specimen thickness increased from 6 to 18 mm or as the groove cavity fraction increased from 29–30% to 38–39%. Analyzing the σ-t curve shapes revealed that the triangular grooved specimens exhibited broad-peak shaped curves, resulting in a greater reduction in I compared to the broadened plateau shape observed in the rectangular grooved specimens. Taking into account both I and amax, the overall energy-absorbing performance of the triangular grooved specimens was better than that of the rectangular grooved specimens. Notably, in the triangular grooved specimens with a high cavity fraction, the triangular embossing intruded into the groove cavities, resembling a 'zipper' mechanism, further enhancing the effectiveness of energy absorption. This study presents a promising approach for developing various grooved Al sheet stacks that exhibit reduced amax and I by strategically exploring suitable groove shapes, cavity fractions, and stack thicknesses, especially in dynamically compressed artillery environments.

Improved Reverse Postauricular Island Flap for Repair of Lower Conjunctival Fornix Retraction.

Repair of lower conjunctival fornix retraction is a great challenge for plastic surgeons in the aspects of orbital prosthesis retaining and cosmetic appearance. Hereby, a 25-year-old woman, suffering from lower conjunctival fornix retraction after the removal of retinoblastoma and radiotherapy, was undertaking the treatment with an improved reverse postauricular island flap for expansion of the lower conjunctival fornix, and volume augmentation of the anophthalmic socket in one stage. The flap was based on the parietal branch of the superficial temporal artery and its vascular architecture to the postauricular vascular system, and successfully transferred by passing through a subcutaneous tunnel. The satisfactory result indicated that the mentioned technique may be a good option in surgical rehabilitation of the stable depth of the lower conjunctival fornix, not only from the reliable blood supply and the suitable thickness of the flap but also from the less donor morbidity without an exposed unsightly scar. Level V.

Sb2S3 Thin-Film Solar Cells Fabricated from an Antimony Ethyl Xanthate Based Precursor in Air.

The rapidly expanding demand for photovoltaics (PVs) requires stable, quick, and easy to manufacture solar cells based on socioeconomically and ecologically viable earth-abundant resources. Sb2S3 has been a potential candidate for solar PVs and the efficiency of planar Sb2S3 thin-film solar cells has witnessed a reasonable rise from 5.77% in 2014 to 8% in 2022. Herein, the aim is to bring new insight into Sb2S3 solar cell research by investigating how the bulk and surface properties of the Sb2S3 absorber and the current-voltage and deep-level defect characteristics of solar cells based on these films are affected by the ultrasonic spray pyrolysis deposition temperature and the molar ratio of thiourea to SbEX in solution. The properties of the Sb2S3 absorber are characterized by bulk- and surface-sensitive methods. Solar cells are characterized by temperature-dependent current-voltage, external quantum efficiency, and deep-level transient spectroscopy measurements. In this paper, the first thin-film solar cells based on a planar Sb2S3 absorber grown from antimony ethyl xanthate (SbEX) by ultrasonic spray pyrolysis in air are demonstrated. Devices based on the Sb2S3 absorber grown at 200 °C, especially from a solution of thiourea and SbEX in a molar ratio of 4.5, perform the best by virtue of suppressed surface oxidation of Sb2S3, favorable band alignment, Sb-vacancy concentration, a continuous film morphology, and a suitable film thickness of 75 nm, achieving up to 4.1% power conversion efficiency, which is the best efficiency to date for planar Sb2S3 solar cells grown from xanthate-based precursors. Our findings highlight the importance of developing synthesis conditions to achieve the best solar cell device performance for an Sb2S3 absorber layer pertaining to the chosen deposition method, experimental setup, and precursors.