Rear Side Research Articles

Experiments on Stability of Armor Rocks on Rear Slope of Rubble Mound Structures under Wave Overtopping Condition with Rectangular Crest Element

In this study, hydraulic model tests were performed to investigate the stability of armor units at harbor side slope for rubble mound structures. The armor units on the rear slope were rocks. The Korean design standard for harbor and fishery port suggested the design figures that showed the ratio of the armor weight for each location of rubble mound structures and it could be known that the same weight ratio was needed to the sea side and rear side slope of rubble mound structures. The crest elements were commonly applied to the design process of rubble mound structures in Korea and the investigation of the effects of super structures would be needed. The damage rate (S =2) was applied and the stable wave height was measured for each test condition. The results were suggested as the armor weight ratio of the rear side slope(armor rock) to the sea side slope (tetrapod) in relation to the relative crest height.

Enhancing photovoltaic efficiency through evaporative cooling and a solar still

The efficiency of photovoltaic panels decreases with the increase in panel temperature while converting light into electricity. The issue of temperature rise and the associated decrease in efficiency has been widely analysed by active and passive cooling methods. In those processes, normally water is used as a cooling medium, and it results in water loss along with power loss due to circulating or compensating for the lost water. The current study aims to address both efficiency as well as water loss by combining an evaporative cooling technique with a solar still. A Photovoltaic panel with rear-side evaporative cooling is attempted by using a jute sack dipped in water at both ends. As a result of capillary action, the water from a solar still rises through the sack and cools the panel’s rear side. Solar still operation is ensured by an extended portion of glass. During desalination, the evaporated vapour from the solar still condenses on the back cover of the glass surface and is collected in a collection trough. As a result, the output power increased by 5.6 % and the electrical efficiency increased by 14.51 % and the surface temperature are reduced by 8°C. After seven hours of sunshine, the proposed PV panels and solar still system produced approximately 550 ml of water.

The role of asymmetric metal flow on weld formation and solidification characteristics during pulsed laser butt welding with assembly tolerance

In comparison to other laser-assisted welding techniques, the pulsed laser welding process (PLBW) provides cost-effectiveness and ease of operation while effectively connecting butt-assembled thin plates with manufacturing tolerances (both air gap and edge misalignment). A combination of numerical simulations and experimental studies was conducted to analyze the forming mechanism and solidification behavior of the weld. In this paper, a transient three-dimensional heat-flow-metallurgical model has been established for a PLBW process of mild steel plates with a thickness of 1.8 mm. The predicted weld pool profiles were consistent with the experimental findings. The finding suggested the molten metal, driven by surface tension and recoil pressure, successively generated liquid bridges on the rear and front sides of the pool. The two sheets were joined as the molten metal gradually solidified. The energy absorptivity was highly correlated with the weld pool and keyhole dynamics, and the laser energy absorbed by the metal was mainly transferred in the form of thermal convection. The kinematic features of the melt were observed by the liquid phase mass transfer rate and surface fluctuations. According to the Fourier analysis results, the molten pool oscillated at the characteristic frequency of the laser pulse frequency. The spatial and temporal distributions of solidification parameters aided in analyzing the solidification features within the pool. The asymmetric flow had a greater influence on the temperature gradient. These findings addressed the roles of PLBW on fluid flow, heat behaviors, and solidification parameters of welds with assembly tolerances, as well as the reasons for improved weld formation.

Single iterated fractal inspired UWB antenna with reconfigurable notch bands for compact electronics

A simple, compact, and low-profile antenna operating over ultrawideband with high gain is presented in this manuscript. The antenna has dimensions of W × L = 19 mm × 21 mm and is placed on the rear side of the FR-4 substrate material. The antenna contains simple geometry, inspired from a circular fractals, which consists of a circular patch with a CPW feedline. The circular patch is loaded with two fractals patches at both top end of the substrate and the rectangular stub is loaded at the lower side, to improve the antenna's bandwidth. The constructed antenna offers a wide band of 3–13.5 GHz. The antenna geometry also contains three semicircular slots, which are etched to generate the notch bands. Each slot is etched step by step, giving notch bands at 3.9 GHz, 5.2 GHz, and 8.1 GHz. In the final stage, two diodes are added to attain reconfiguration. The antenna offers moderate gain and high radiation efficiency. The hardware model of antenna is engineered to verify the simulated results. Moreover, the antenna is compared with other works in literature. The outcomes of the proposed antenna and comparison with the literature work make the suggested work the best candidate for future UWB portable devices.

Addressing sodium ion-related degradation in SHJ cells by the application of nano-scale barrier layers

Silicon heterojunction (SHJ) solar cells are renowned for their high efficiency. However, SHJ solar cells are susceptible to various contaminants, leading to significant performance degradation when exposed to damp-heat conditions (e.g., 85 °C and 85% relative humidity). Sodium (Na) has been identified as one of the main contributors to degradation in silicon solar modules subjected to damp-heat conditions. This work investigates the role of an ultra-thin AlOx capping layer (∼10 nm) in preventing the failure in SHJ cells caused by Na-related contaminants. NaCl is applied directly to the solar cell, and the unencapsulated cell undergoes a damp heat test at 85 °C and 85% relative humidity (DH85). It is found that without the AlOx barrier layer, the SHJ cells experience a relative reduction in power of ∼30%rel after only 20 h at DH85. Both the front and rear sides of the cell degrade when exposed to NaCl. This is primarily due to a deterioration of the Ag contact resulting in increased series resistance (Rs), and decrease in fill factor (FF), and an increase in recombination, leading to a significant drop in open-circuit voltage (Voc), particularly when NaCl is applied on the rear side. However, when an AlOx barrier layer is applied to the SHJ cells, the performance losses caused by NaCl are significantly reduced to only ∼3.3%rel. The loss in Voc on the rear side is completely suppressed, and there is only a slight increase in Rs of ∼50%rel compared to ∼300%rel increase in Rs for cells without the AlOx barrier layer. These findings indicate that the ultra-thin AlOx barrier layer provides effective protection for SHJ cells against Na ions, mitigating both Rs and recombination losses. This AlOx barrier layer depositing method is compatible with existing industrial mass-production ALD tools and thus presents a viable solution at the cell level for SHJ cells.

Comparing methods for the long-term performance assessment of bifacial photovoltaic modules in Nordic conditions

The main objective of this study is to discover which performance loss rate (PLR) calculation methods provide the most reliable results for vertical bifacial photovoltaics (VBPV) in Nordic conditions. For this purpose, over 1600 filter-metric-aggregation-model combinations for PLR calculation are compared. Accurate determination of PLR is crucial for estimating the economic profitability of a PV system, but standardized methodology is lacking as is the understanding on how the common PLR calculation frameworks perform for both VBPV technology and Nordic climatic region. Here, four-year, minute-resolution datasets from adjacent VBPV modules and a weather station in Turku, Finland (60°N) are used. After removing crude outliers, a benchmark PLR of −1.46±0.03 %/year was obtained by averaging the remaining over 1200 filter-metric-aggregation-model combinations. The year-on-year method with a daily/weekly aggregated temperature- and irradiance-corrected performance model was found robust and reliable to Nordic high seasonality. In contrast, several commonly used methods, such as the PVUSA model, produced unrealistic results. Unexpectedly, temperature correction increased the seasonal pattern of the performance ratio, and PLR varied with irradiance conditions and between the front and rear sides of the module. This work expands the best practices of PLR calculation to complement the development of global PLR calculation standards.

Understanding and mitigating resistive losses in fired passivating contacts: role of the interfaces and optimization of the thermal budget

This work presents a study of p-type passivating contacts based on SiCx formed via a rapid thermal processing (RTP) step, using conditions compatible with the firing used to sinter screen-printed metallization pastes in industry. The contributions of the two interfaces (wafer/contact and contact/metal) to the contact resistivity are first decorrelated, identifying tunnelling at the wafer interface as the main contribution. We then investigate the influence of the active dopant concentration on the contact resistivity and the SiCx sheet resistance and propose strategies to reduce both resistances by increasing the thermal budget applied during RTP. Lastly, we discuss potentials and limitations of implementing the investigated stacks as rear side contacts of p-type devices with localized metallization. We demonstrate that increasing the thermal budget during RTP can effectively mitigate resistive losses and enhance contact performance and we show that an oxide layer that can withstand high thermal budgets is the key factor for obtaining simultaneously high passivation quality and good electrical properties. We investigate three different oxide types grown by HNO3 immersion, UV-O3 exposure and N2O plasma oxidation. The latter is demonstrated to be a promising candidate for an application in devices fabricated with high RTP thermal budget.

Effect of Trimmed Rear Shroud on Performance and Axial Thrust of Multi-Stage Centrifugal Pump With Emphasis on Visualizing Flow Losses

Abstract Multi-stage centrifugal pumps are frequently used in high-lift applications and consume considerable energy, but suffer from poor performance and large axial force. The rear shroud of impeller is trimmed for reducing axial thrust, but this degrades performance. This study analyzes performance degradation and optimizes performance and axial force. Experiments and simulations are conducted on different ratios of rear shroud to front shroud (λ). Total pressure losses are calculated, and flow losses are visualized using the entropy generation method. Both measured and simulated performances decrease as the rear shroud is trimmed. Designs with different λ meet the head coefficient requirement of 1.1. However, λ of 0.86 has the best efficiency of 42.7%, λ of 0.83 reaches 42.5%, λ of 0.8 shows the lowest efficiency of 39.9%. Efficiency in the middle channel improves as the rear shroud is trimmed, but this cannot offset increased losses in the impeller and rear side chamber. Entropy production is exacerbated in the axial passage between impeller and rear side chamber due to the collision between impeller-driven flow and pressure-driven backflow. When λ is reduced by 0.03, axial thrust drops by 7%. To compromise between performance and axial thrust, λ should be designed at 0.83.

Influence of Al2O3/SiNx Rear-Side Stacked Passivation on the Performance of Polycrystalline PERC Solar Cells

In recent years, polycrystalline passivated emitter and rear cell (PERC) solar cells have developed rapidly, but less research has been conducted on the preparation process of their rear side passivation layers on standard solar cell production lines. In this work, a Al2O3/SiNx rear side stacked passivation layer for polycrystalline PERC solar cells was prepared using the plasma- enhanced chemical vapor deposition (PECVD) method. The effects of different Al2O3 layer thicknesses (6.8~25.6 nm), SiNx layer thicknesses (65~150 nm) and SiNx refractive indices (2.0~2.2) on the passivation effect and electrical performance were systematically investigated, which were adjusted by TMA flow rate, conveyor belt speed and the flow ratio of SiH4 and NH3, respectively. In addition, external quantum efficiency (EQE) and elevated temperature-induced degradation experiments were also carried out to check the cell performance. The results showed that the best passivation effect was achieved at 10.8 nm Al2O3 layer, 120 nm SiNx layer and 2.2 SiNx layer refractive index. Under the optimal conditions mentioned above, the highest efficiency was 19.20%, corresponding Voc was 647 mV, Isc was 9.21 A and FF was 79.18%. Meanwhile, when the refraction index was 2.2, the EQE of the cell in the long-wavelength band (800–1000 nm) was improved. Moreover, the decrease in conversion efficiency after 45 h LeTID was around 0.55% under the different refraction indices. The above results can provide a reference for the industrial production of polycrystalline PERC solar cells.

Optical modeling and characterization of bifacial SiNx/AlOx dielectric layers for surface passivation and antireflection in PERC

AbstractIn this research, we analyzed the impact that the optical characteristics of dielectric surface passivation and antireflection coating schemes have on the performance of passivated emitter and rear cell (PERC) silicon solar cells. We employed wafer ray tracer (WRT) and automate for simulation of heterostructure (AFORS‐HET) simulations, as well as experimental characterization of fabricated thin film coatings. We investigated three distinct front surface morphologies: planar surface, upright pyramids, and inverted pyramids. Using WRT, we calculated the photogeneration current densities (JG) for PERC devices with three schemes: (i) SiNx/AlOx as antireflection coating and passivation stacks on both the front and rear sides, (ii) SiNx antireflection coating on the front side and AlOx passivation layer on the rear side, and (iii) SiNx/AlOx as antireflection coating and passivation stacks on the front side with an AlOx passivation layer on the rear side. Following simulation with optimal JG, two schemes are experimentally evaluated: PECVD SiNx (70 nm) and atomic layer deposition (ALD) AlOx (15 and 25 nm). We confirmed the growth effects and optical properties using X‐ray diffraction, Raman spectroscopy, effective lifetime, and refractive index measurements. The most favorable electrical properties were obtained with SiNx (70 nm, front) and AlOx (25 nm, front and rear), where the AlOx can be deposited via ALD bifacially on a single step, minimizing processing while maintaining passivation performance. Finally, we used AFORS‐HET to simulate the maximum performance of PERC bearing such films. The results showed a Voc = 0.688 V, Jsc = 41.42 mA/cm2, FF = 84%, and packing conversion efficiency (PCE) = 24.12% as the optimal solar cell performance values.

Numerical Study of the Effect of Imaginary Circle Diameter on the Combustion in a Corner-tangentially-fired Boiler

The key factor affecting the combustion and operation of corner tangentially fired boilers (CTFBs) is the diameter of the imaginary circle. In this paper, the temperature and reducing gas distribution in a 350 MW supercritical CTFB were studied numerically, and the influence of imaginary circle diameter on combustion characteristics was analyzed. The results show that: 1) When the diameters of the imaginary circles of the primary and secondary air are decreased, there will be a delay in combustion. This is not profit to the steady-state burning of coal powder. In addition, the temperature near the water wall decreases, and the volume fraction of CO and H2S decreases on the rear side of the main combustion area, but increases significantly on the side of the fire. 2) By reducing only the diameter of the imaginary circle of primary air, the ignition distance of pulverized coal in the lower burner can be advanced, which is profit to improving combustion stability at low loads. Besides, the temperature, CO and H2S volume fraction near the water wall all decrease. 3) When the imaginary circle diameters of primary and secondary air in the upper part of the furnace are reduced, the temperature, volume fraction of CO and H2S in the adjacent layer near the water wall are increased.

Experimental study on fire characteristics of sidewall fires in a long-narrow compartment with multiple lateral openings

This experimental study delves into the fire characteristics within a long and narrow compartment equipped with multiple lateral openings. The investigation encompasses aspects such as radiant heat flow, temperature distribution, and smoke layer height. The presence of lateral openings introduces asymmetry in suction, resulting in augmented radiative heat flow on the rear side of the fire source compared to the front and left sides. Smoke stratification remains stable, with minimal temperature influence from the fire source power at one opening and negligible impact at the other. Employing a customized two-dimensional method for thermal estimation, our experimental data display lower results than previous predictions due to structural disparities. The utilization of the N-percentage rule unveils two discernible regions in smoke layer height behavior: stable and decreasing, a pattern consistent across varying heat release rates. These insights offer valuable predictive tools for discerning fire characteristics in elongated, restricted compartments with multiple lateral openings. Consequently, this study enhances comprehension and informs safety measures within such configurations, contributing to the broader field of fire safety engineering.

Thermal analysis on the performance of a finned hybrid bi-fluid PVT system

The increase in the temperature of solar panels is a significant issue that leads to low performance of photovoltaic (PV) cells. This numerical investigation aims to perform a transient analysis employing commercial computational fluid dynamics code and improve the electrical energy of the PV panel in a hybrid system by utilizing both water and air and adding fins. The system was cooled from the rear side of the PV/thermal (PVT) module by flowing water at different mass flow rates (ṁw = 0.010 kg/s to 0.020 kg/s) through aluminum tubes adhered to an aluminum absorbent plate. Moreover, the air passes through the channel that contains aluminum fins welded to the absorbent plate and next to the tubes. The objective is to analyze the effects of ṁw and fins on the flow and the thermal efficiency. A comparison was made between two modules of bi-fluid (BF) PVT manifolds: module 1 without fins and module 2 with fins. The effect of the operating temperature rise on the PV panel and the total thermal efficiency was evaluated. The attained results presented a linear decrease in thermal efficiency with the increase of ṁw. The thermal efficiency of modules 1 and 2 at ṁw = 0.010 kg/s is 50% and 60%, respectively. Under the solar irradiance and ṁw = 0.010 kg/s in module 2, an improvement of thermal efficiency of about 5.7% was recorded compared to module 1. The hybrid PVT BF system with fins (module 2) operating with ṁw = 0.010 kg/s has proved that adding fins to the PVT system was very effective in maintaining the system’s thermal efficiency at its highest record.

Design and simulation of a highly efficient CuBi2O4 thin-film solar cell with hole transport layer

The advancement of thin-film photovoltaic technologies is increasing extensively in today’s world owing to their outstanding optical properties, simple fabrication process, and low-cost. In this work, a solar cell capacitance simulator in one-dimension (SCAPS-1D) has been used to evaluate the output parameters of the heterojunction CuBi2O4-based solar cells with various hole transport layers (HTLs). It is revealed that a p-type cuprous oxide (Cu2O) semiconductor as an HTL ensures proper band alignment at Cu2O/CuBi2O4 interface. The recombination due to minority electrons at the rear side of the CuBi2O4 solar structure with Cu2O HTL can be diminished notably than the device with other HTLs, thus improving the overall outputs of the suggested Cu2O/CuBi2O4/CdS/FTO heterostructure. To realize the behaviors of the proposed PV cell, the thickness and carrier concentration of various films, bulk defects, interface defects, cell resistances, and rear electrode work function of the anticipated CuBi2O4 thin-film photovoltaic device have been optimized. The recombination rates at the interfaces in the proposed heterostructure are also calculated. Moreover, to outline the effects of device input parameters of various materials on vital PV output parameters, adaptable machine learning algorithms have been used to train, test, and calculate the output datasets. High accuracy and low error metrics are confirmed for both the train and test datasets. With 1.0 μm absorber thickness, the efficiency of 29.2% with open-circuit voltage (Voc) of 1.02 V, short-circuit current density (Jsc) of 32.49 mA/cm2, and fill factor (FF) of 87.91% is found for the anticipated solar cell. This investigation suggests that the Cu2O can be effectively employed to scheme a highly efficient, stable, and economical CuBi2O4 solar device.

Detailed investigation of electrical and optical properties of textured n-type and roughened p-type tunnel oxide passivated contacts for screen-printed double-side passivated contact silicon solar cell application

This paper presents detailed characterization and analyses of the optical, electrical, and contact properties of a 35 nm phosphorus-doped (n-type) polysilicon (poly-Si) and a 250 nm boron-doped (p-type) poly-Si deposited respectively on textured and roughed surface. These layers could be applied respectively to the front and rear sides of an n-type Si to produce back junction bifacial screen-printed double-side tunnel oxide passivated contacts (DS-TOPCon) solar cells. Optical and device modeling revealed a short circuit current density loss of 1.5 mA/cm2 and 0.5 mA/cm2 due to absorption in the front n-TOPCon and rear side p-TOPCon layers, respectively. The passivation and contact properties including metalized and unmetallized recombination current density (J0), as well as contact resistivity, were determined as a function of contact firing temperature in the range of 700∼800℃. The passivation quality of the front thin n-TOPCon was found to deteriorate with increased firing temperature while the rear thick p-TOPCon improved. The study showed that the simulated contact firing at 730℃ resulted in the best unmetallized double-side TOPCon precursor, with an excellent implied open-circuit voltage of 730 mV and implied fill factor of ∼86 %. However, the metalized J0 increased and contact resistivity decreased monotonically with the increase in the firing temperature. The 2D device simulations revealed that these layers can produce screen-printed DS-TOPCon cells with an efficiency of ∼22.5 %. Solar cell modeling also showed that the DS-TOPCon solar cell efficiency can reach 24.1 % by decreasing the n-TOPCon thickness to 20 nm and lowering the full area metalized J0 to ∼100 mA/cm2.

Accelerated damp-heat testing at the cell-level of bifacial silicon HJT, PERC and TOPCon solar cells using sodium chloride

Bifacial passivated emitter and rear cells (PERC) currently have the highest share in the photovoltaic market. However, heterojunction (HJT) and tunnel oxide passivated contact (TOPCon) solar cells are expected to gain significant market share shortly. Despite technological advancements, concerns about the reliability of HJT and TOPCon technologies when deployed in the field still need to be addressed. This work investigates the impact of sodium chloride (NaCl) on damp-heat-induced degradation in bifacial HJT, PERC, and TOPCon solar cells by exposing the solar cells to NaCl before damp heat (DH) testing. It is found that among all investigated cell technologies, TOPCon solar cells degrade the most with maximum power (Pmax) loss of up to ∼75%rel, followed by HJT (Pmax drops ∼50%rel), and PERC cells (Pmax drops only ∼10%rel) after 20 h of DH testing, mainly attributed to an increase in Rs on the front side of TOPCon cells, both sides of HJT cells and the rear side of PERC cells. The front of the PERC and the rear of the TOPCon solar cell are found to be stable. The rise in Rs is attributed to the corrosion of the metal contact, which is caused by a high amount of Na+ and Cl− ions penetrating the metal contact. This corrosion leads to increased porosity, detachment of the contact from the silicon interface, and increased recombination loss in some cases. These results are crucial for all cell technologies as they highlight the potential failures that could occur in the field. Na+ and/or Cl− ions are common contaminants present in solar glass, human fingerprints, soldering flux, rainwater, soil/dust, and seawater. During field operation, these ions have the potential to penetrate and directly interact with solar cells. In our view, the preferred solution is for the solar cells to be corrosion-resistant, which can be rapidly assessed using the method presented in this work.

Development and challenges of bifacial photovoltaic technology and application in buildings: A review

Bifacial photovoltaic (bPV) modules can both obtain the front and rear light to get higher power output, which has attracted extensive attention and is expected to substitute for mono-facial photovoltaic technology (mPV). The bPV technology has always been developing with new technologies and applications constantly emerging. However, there is little review on bPV technology applied in buildings. The current reviews mainly focus on the principle and performance research of bPV technology. This work focuses on reviewing the application status of bPV technology in buildings, which aims to contribute to the large-scale application of bPV technology in buildings and reduce building energy problems. The latest innovative development of bPV technology and the key issues in the application of bPV technology in buildings were summarized and analyzed. For the further development of bPV technology, research on battery materials and structures is beneficial for improving the utilization rate of light at different wavelengths. For the building application of bPV technology, the issue of uneven irradiation of the rear side is a key factor hindering the large-scale application of bPV in buildings, and the use of back reflectors can effectively alleviate this problem.

Fluorene-naphthalene Schiff base as a smart pigment in invisible ink with multiple security features for advanced anticounterfeiting and forensic applications

Smart functional materials with captivating optical properties are of immense importance due to their versatile applicability in anticounterfeiting and forensic science. A fluorene-naphthalene Schiff base (FNH) that displays aggregation induced emission, mechanofluorochromism and excitation wavelength dependent fluorescence inherent to the pristine and ground samples is synthesized. Water/solvent-based invisible security inks for flexo/screen printing were formulated using FNH as a smart pigment to check the originality of documents/branded products etc. The prints with good photostability, adherence to substrate and rub resistance are invisible in daylight showcasing multiple non-destructive and destructive techniques to authenticate the document. The inked area on UV dull paper substrate exhibits a weak emission, which is observed by the forger under UVA light. However, the user can validate the authenticity of the document by rubbing the print with hard objects, especially using a metal coin or glass rod to perceive a human eye detectable intensification in the orange fluorescence under the same illumination source. The intensity of the orange fluorescence reverts to the original, which enables the reuse of the security document after originality check. Yet another nondestructive authentication method is to observe a cyan fluorescence from the print and orangish yellow fluorescence from the rubbed printed region when shined with a 270–400 nm light source, whereas a cyanish green fluorescence both from the unrubbed and rubbed regions of the print when illuminated with a visible light source ranging from 420 to 480 nm. An additional verification through a destructive technique is to perceive red and yellow fluorescence of the ink film upon contact with THF and NaOH/KOH, respectively and a penetrating red fluorescence from the rear side of the THF-exposed printed area of the paper. The multi-level security features that cannot be easily replicated by the forger but allows a simple and easy validation process by the user are unique to FNH, used as a single pigment in the inks. Further, the applicability of the ground FNH in forensic science is established to distinctly observe Level I to II details of latent fingerprints.

Missile thermal emission flow field under the synergistic effect of deep reinforcement learning and wireless sensor network

AbstractThe vehicle-mounted missile vertical thermal emission not only has excellent maneuverability, randomness, and concealment, but also has a short response time, good versatility, and high reliability, so it is widely used. In order to explore the gas flow field of thermal emission of the vehicle-mounted missile, firstly, this study introduces the theoretical basis of deep reinforcement learning (DRL) algorithm and wireless sensor network (WSN). Secondly, combining WSN and DRL, a WSN technology based on DRL is proposed. Finally, the DRL-based WSN technology is applied to the vertical thermal emission of the vehicle-mounted missile. In addition, the flow field simulation software is employed to simulate and compare the influence of the single-side and double-side diversion schemes of the gas flow discharged by the diverter on the open ground field flat collection launcher, and the diversion characteristics of the two schemes are obtained. The results show that in the single-side diversion scheme, the impact and ablation area of the gas jet on the ground mainly appear at the rear side of the diversion device, and the ablation area of the gas jet on the launcher vehicle is mainly at its tail end. While the ablative site and shock of the double-side diversion scheme on the ground mainly appear on both sides of the diversion, and the ablative part of the gas jet to the launcher is mainly present at the bottom of the frame and the inside surface of the tire. The study of missile thermal emission flow fields based on DRL and WSN has certain theoretical significance for the flow field variation of missile launching.

Explosion and Dynamic Transparency of Low-Density Structured Polymeric Targets Irradiated by a Long-Pulse KrF Laser

The hydrodynamics of plasma formed in the interaction of 100 ns UV KrF laser pulses with foam targets with volume densities from 5 to 500 mg/cm3 was studied. Initial and dynamic transmittance at 248 nm wavelength were measured. At intensities of about 1012 W/cm2, the propagation rates of radiation through foam targets reached 80 km/s, while plasma stream velocities from both the front and rear sides of targets were approximately the same, ~ 75 km/s, which confirms a volumetric absorption of radiation within the target thickness and the explosive nature of the plasma formation and expansion.