With the k-ε renormalization group turbulence model, the drag reduction mechanism of three- dimensional spherical crown microstructure of different protruding heights distributing on the groove ...surface was studied in this paper. These spherical crown microstructures were divided into two categories according to the positive and negative of protruding height. The positive spherical crown micro-structures can destroy a large number of vortexes on the groove surface, which increases relative friction between water flow and the groove surface. With decreasing the vertical height of the spherical crown microstructure, the number of rupture vortexes gradually decreases. Due to the still water area causes by the blocking effect of the spherical crown microstructure, it was found that the shear stress on the groove surface can be reduced, which can form the entire drag reduction state. In another case, the spherical crown microstructures protrude in the negative direction, vortexes can be generated inside the spherical crown, it was found that these vortexes can effectively reduce the resistance in terms of pressure and friction. In a small volume, it was shown that the surface drag reduction rate of spherical crown microstructures protrudes in negative directions can be the same as high as 24.8%.
2D semiconductors have emerged as candidates for next‐generation electronics. However, previously reported 2D transistors which typically employ the gate‐first process to fabricate a back‐gate (BG) ...configuration while neglecting the thorough impact on the dielectric capping layer, are severely constrained in large‐scale manufacturing and compatibility with complementary metal–oxide–semiconductor (CMOS) technology. In this study, dual‐gate (DG) field‐effect transistors have been realized based on wafer‐scale monolayer MoS2 and the gate‐last processing, which avoids the transfer process and utilizes an optimized top‐gate (TG) dielectric stack, rendering it highly compatible with CMOS technology. Subsequently, the physical mechanism of TG dielectric deposition and the corresponding controllable threshold voltage (VTH) shift is investigated. Then the fabricated TG‐devices with a large on/off ratio up to 1.7 × 109, negligible hysteresis (≈14 mV), and favorable stability. Additionally, encapsulated TG structured photodetectors have been demonstrated which exhibit photo responsivity (R) up to 9.39 × 103 A W−1 and detectivity (D*) ≈2.13 × 1013 Jones. The result paves the way for future CMOS‐compatible integration of 2D semiconductors for complex multifunctional IC applications.
The approach involves in situ 2D material growth on Si/SiO2 substrates facilitated by the CVD system, followed by the gate‐last processing integration of devices. This demonstrates seamless compatibility with CMOS technologies, based on wafer‐scale monolayer 2D semiconductors, showcasing potential in transistor and encapsulated photodetector applications. This research paves the way for moving 2D semiconductor manufacturing from laboratory to industrial scale.
Abstract 2D semiconductors have emerged as candidates for next‐generation electronics. However, previously reported 2D transistors which typically employ the gate‐first process to fabricate a ...back‐gate (BG) configuration while neglecting the thorough impact on the dielectric capping layer, are severely constrained in large‐scale manufacturing and compatibility with complementary metal–oxide–semiconductor (CMOS) technology. In this study, dual‐gate (DG) field‐effect transistors have been realized based on wafer‐scale monolayer MoS 2 and the gate‐last processing, which avoids the transfer process and utilizes an optimized top‐gate (TG) dielectric stack, rendering it highly compatible with CMOS technology. Subsequently, the physical mechanism of TG dielectric deposition and the corresponding controllable threshold voltage ( V TH ) shift is investigated. Then the fabricated TG‐devices with a large on/off ratio up to 1.7 × 10 9 , negligible hysteresis (≈14 mV), and favorable stability. Additionally, encapsulated TG structured photodetectors have been demonstrated which exhibit photo responsivity ( R ) up to 9.39 × 10 3 A W −1 and detectivity ( D * ) ≈2.13 × 10 13 Jones. The result paves the way for future CMOS‐compatible integration of 2D semiconductors for complex multifunctional IC applications.
Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) with earth‐abundant and environmental‐benign constituents has been regarded as a promising solar energy harvesting material for green and cost‐effective photovoltaic ...applications. The record efficiency of CZTSSe solar cells has recently been refreshed twice after years‐long stagnation, keeping it in the spotlight. Nevertheless, the champion efficiency of 13.6% is still far behind its counterpart Cu(In,Ga)Se2 (CIGS) (23.35%) despite being endowed with a similar electronic structure and nearly‐identical device architecture. In fact, CZTSSe solar cells are more susceptible to non‐radiative recombination at bulk and interfaces, which must be improved for further efficiency advancement. In this review, the state‐of‐art strategies to enhance the power conversion efficiency of CZTSSe solar cells are summarized and discussed, with focus given to three critical device regions i) kesterite absorber, ii) buffer/kesterite interface, and iii) kesterite/back contact interface. With the further elucidation of the latest progress and disclosure of fundamental mechanisms, novel insights toward high‐efficiency kesterite solar cells are proposed.
State‐of‐art strategies addressing the dominant recombination in kesterite Cu2ZnSn(S,Se)4 solar cells are reviewed. Attention is focused on the kesterite absorber, front p‐n heterojunction, and kesterite/back contact interface, as they primarily limit the performance of kesterite devices and can be improved simultaneously. By systematically scrutinizing these highly compatible measures, promising research directions are proposed to stimulate further progress and strategy integration.
•An innovative way (induction heating) to heat the receiver is numerically studied.•A 3D model, coupling electromagnetic, thermal, and turbulent fields, is developed.•An induction heating receiver ...tube experiment is carried out to verify the model.•The preheating and salt circulation processes of the receiver are studied.•The thermomechanical performance of the tube and heating efficiency are studied.
Induction heating is an emerging research method that can recreate half-perimeter heating of a receiver tube in a tower-concentrating solar power plant. In this study, a three-dimensional (3D) field numerical model that couples electromagnetic induction, heat transfer, and turbulence, is developed to study the thermal performance of a receiver tube during the preheating process and under salt circulation conditions. The effects of the coil-to-tube distance, coil power, molten salt inlet temperature, molten salt inlet velocity, and ambient temperature were investigated. Furthermore, the thermal stress distribution and evolution in the tube were calculated. The heat generation was fund to be concentrated on the outer surface of the tube front. The increase in coil power significantly accelerated the preheating process. With increase in the coil power from 200 to 500 W, the time required for the maximum tube temperature to reach 350 °C reduced by 55.67 %. The heating efficiency increased with increasing coil power, molten salt inlet velocity, and ambient temperature decreased with increasing coil-to-tube distance and molten salt inlet temperature. Among them, the molten salt inlet temperature had a more significant effect. As it increased from 250 to 400 °C, the heating efficiency decreased from 47.17 to 18.82 %. The maximum and minimum equivalent thermal stresses at preheat stabilization were reached at θ = 0° and θ = 45°, respectively. Furthermore, the equivalent thermal stress at preheat stabilization differed from that with salt circulation by only 4.46 %.
The pathogenesis of aortic dissection (AD), an aortic disease associated with high mortality, involves significant vascular inflammatory infiltration. However, the precise relationship between ...perivascular adipose tissue (PVAT) and aortic dissection remains incompletely understood. The objective of this study is to investigate the role of PVAT inflammation in the pathogenesis of aortic dissection and identify novel therapeutic targets for this disease. The mouse model of aortic dissection was established in this study through intraperitoneal injection of Ang II and administration of BAPN in drinking water. Additionally, control groups were established at different time points including the 2-week group, 3-week group, and 4-week group. qPCR and immunohistochemistry techniques were employed to detect the expression of inflammatory markers and RUNX1 in PVAT surrounding the thoracic aorta in mice. Additionally, an aortic dissection model was established using RUNX1 knockout mice, and the aforementioned indicators were assessed. The 3T3-L1 cells were induced to differentiate into mature adipocytes in vitro, followed by lentivirus transfection for the knockdown or overexpression of RUNX1. The study aimed to investigate the potential cell-to-cell interactions by co-culturing 3T3-L1 cells with A7r5 or RAW264.7 cells. Subsequently, human aortic PVAT samples were obtained through clinical surgery and the aforementioned indicators were detected. In comparison to the control group, the aortic dissection model group exhibited decreased expression of MMP-2 and NF-κB in PVAT, while TNF-α and RUNX1 expression increased. Suppression of RUNX1 expression resulted in increased MMP-2 and NF-κB expression in PVAT, along with decreased TNF-α expression. Overexpression of RUNX1 upregulated the expression levels of NF-Κb, MMP-2, and TNF-α in adipocytes, whereas knockdown of RUNX1 exerted an opposite effect. Macrophages co-cultured with adipocytes overexpressing RUNX1 exhibited enhanced CD86 expression, while vascular smooth muscle cells co-cultured with these adipocytes showed reduced α-SMA expression. In human samples, there was an increase in both RUNX1 and MMP-2 expression levels, accompanied by a decrease in TNF-α and NF-Κb expression. The presence of aortic dissection is accompanied by evident inflammatory alterations in the PVAT, and this phenomenon appears to be associated with the involvement of RUNX1. It is plausible that the regulation of PVAT's inflammatory changes by RUNX1/NF-κB signaling pathway plays a role in the pathogenesis of aortic dissection.
•The seepage blocking characteristics analyses of molten salt in tank foundations under different operating conditions were studied.•A method for blocking molten salt seepage based on the presetting ...metal mesh was proposed.•Parametric analysis and optimization were conducted to the proposed seepage blocking method.
Leakage of molten salt storage tanks in concentrated solar power plants poses a major threat to operating safety. This paper focuses on arranging metal mesh in the storage tank foundation to control the seepage and migration range of molten salt in the thermal-steady foundation materials after leakage occurs. The influences of different conditions, including the metal mesh aperture, metal mesh position, operating temperature, and the mass of leaked molten salt, on the blocking effect were investigated through a custom-built experimental system that modeled the actual leaking process. The results showed that the metal mesh can effectively block seepage of molten salt. When the metal mesh aperture is made smaller or the mesh is placed further toward the bottom of the tank, the metal mesh has a significant blocking effect on molten salt seepage. Especially when the metal mesh aperture is 0.15 mm and the depth of placement is 325 mm, seepage of molten salt can be completely blocked. Nevertheless, it has been found that the depth of molten salt seepage distinctly increases with higher operating temperature or larger leaked molten salt mass. These experimental results will provide references for pollution control and disposition of molten salt leakage accidents and help power plant engineers re-examine tank foundation designs.
The Cd-free Cu
ZnSnS
(CZTS) solar cell is an ideal candidate for producing low-cost clean energy through green materials owing to its inherent environmental friendliness and earth abundance. ...Nevertheless, sulfide CZTS has long suffered from severe open-circuit voltage (V
) deficits, limiting the full exploitation of performance potential and further progress. Here, an effective strategy is proposed to alleviate the nonradiative V
loss by manipulating the phase evolution during the critical kesterite phase formation stage. With a Ge cap layer on the precursor, premature CZTS grain formation is suppressed at low temperatures, leading to fewer nucleation centers at the initial crystallization stage. Consequently, the CZTS grain formation and crystallization are deferred to high temperatures, resulting in enhanced grain interior quality and less unfavorable grain boundaries in the final film. As a result, a champion efficiency of 10.7% for Cd-free CZTS solar cells with remarkably high V
beyond 800 mV (63.2% Schockley-Queisser limit) is realized, indicating that nonradiative recombination is effectively inhibited. This strategy may advance other compound semiconductors seeking high-quality crystallization.
The Cd‐free Cu2ZnSnS4 (CZTS) solar cell is an ideal candidate for producing low‐cost clean energy through green materials owing to its inherent environmental friendliness and earth abundance. ...Nevertheless, sulfide CZTS has long suffered from severe open‐circuit voltage (VOC) deficits, limiting the full exploitation of performance potential and further progress. Here, an effective strategy is proposed to alleviate the nonradiative VOC loss by manipulating the phase evolution during the critical kesterite phase formation stage. With a Ge cap layer on the precursor, premature CZTS grain formation is suppressed at low temperatures, leading to fewer nucleation centers at the initial crystallization stage. Consequently, the CZTS grain formation and crystallization are deferred to high temperatures, resulting in enhanced grain interior quality and less unfavorable grain boundaries in the final film. As a result, a champion efficiency of 10.7% for Cd‐free CZTS solar cells with remarkably high VOC beyond 800 mV (63.2% Schockley–Queisser limit) is realized, indicating that nonradiative recombination is effectively inhibited. This strategy may advance other compound semiconductors seeking high‐quality crystallization.
A Ge cap layer is applied atop the Cu2ZnSnS4 (CZTS) precursor to enable phase evolution intervention during sulfurization. It defers the crystallization of CZTS to higher temperatures, thereby reducing grain boundaries and enhancing crystallinity in the final CZTS film. With this strategy, an exceptional open‐circuit voltage exceeding 800 mV and a champion efficiency of 10.7% Cd‐free CZTS solar cells are demonstrated.
The persistent double layer structure whereby two layers with different properties form at the front and rear of absorbers is a critical challenge in the field of kesterite thin‐film solar cells, ...which imposes additional nonradiative recombination in the quasi‐neutral region and potential limitation to the transport of hole carriers. Herein, an effective model for growing monolayer CZTSe thin‐films based on metal precursors with large grains spanning the whole film is developed. Voids and fine grain layer are avoided successfully by suppressing the formation of a Sn‐rich liquid metal phase near Mo back contact during alloying, while grain coarsening is greatly promoted by enhancing mass transfer during grain growth. The desired morphology exhibits several encouraging features, including significantly reduced recombination in the quasi‐neutral region that contributes to the large increase of short‐circuit current, and a quasi‐Ohmic back contact which is a prerequisite for high fill factor. Though this growth mode may introduce more interfacial defects which require further modification, the strategies demonstrated remove a primary obstacle toward higher efficiency kesterite solar cells, and can be applicable to morphology control with other emerging chalcogenide thin films.
An effective growth approach for fabricating large‐grain spanning monolayer Cu2ZnSnSe4 absorbers is developed based on sputtered metal precursors. This desired morphology demonstrates pronouncedly enhanced photogenerated carrier collection in the long wavelength region and a favorable quasi‐Ohmic back contact interface, removing one of the primary obstacles toward higher efficiency comparable with Cu(In,Ga)Se2 and CdTe solar cells.
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