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Aimed at the new application scenario of laser, a test platform was established to study the coating material da-mage features induced by the interaction of the Ma=6 tangential air flow and the continuous laser irradiation. The laser-damaged characteristics of the coating materials in still air and Ma=6 ground-simulated airflows, as well as the corresponding interference flow structures, were presented. Compared with the laser-irradiation ablation phenomenon of the coating materials in still air, the laser-induced damage characteristics of coating materials are significantly different in hypersonic tangential airflows. Under the interaction of hypersonic airflows, the coating materials show a larger damage area when the laser power is low, while the coating materials form deeper ablation pits when the laser power is high. Due to the disturbance from the material ablation, flow patterns similar to those produced by a thermal jet or small protrusion are formed around the ablative structure of coating materials. This phenomenon, in turn, affects the ablation of coating materials, producing a strong coupling phenomenon between hypersonic flow and laser ablation. The results can provide important guidance for engineering applications.

The quest for clean, efficient engine technologies is imperative in reducing transportation’s environmental impact. Hydrogen, as a zero-emission fuel, offers significant potential for internal combustion engines but faces challenges such as optimizing engine performance and longevity. Water injection is proposed as a solution, yet its effects on engine performance require thorough investigation. This study bridges the knowledge gap by examining various water injection ratios (WIRs) and their impact on engine performance, focusing on the balance between power output and engine longevity. We identified the existence of an optimum WIR (e.g., 10% in this study), which provides peak performance with minimal adverse effects on engine performance and health. Computational simulations of a single-cylinder engine revealed how WIRs influence in-cylinder temperature, pressure, and IMEP, emphasizing the nuanced benefits of water injection. Additionally, our analysis of turbulence, through TKE and dissipation rate, deepens the understanding of combustion and fuel efficiency in hydrogen engines. This research provides valuable guidance for optimizing engine operations and paves the way for advanced water injection systems in hydrogen engines, marking a significant step towards cleaner engine technology.

Although lignin improves the strength and modulus of soil, it is less active when unmodified, and it exhibits more limited effects on soils in combination with traditional Ca-based curing agents. Lignin-solidified soil also exhibits deficiencies, such as poor durability under dry–wet cycling conditions, and thus, the amelioration effect is limited. This study investigated the enhancement of cement-solidified soil using hydroxylated lignin with sodium silicate and quicklime used as activators to improve the engineering performance and durability of the treated soil. Using respective cement, sodium silicate, quicklime, and lignin contents of 7%, 0.4%, 0.2%, and 0.2% with respect to the dry mass of the slag soil, the strength and cohesion of the composite-solidified soil were 1.5 times those of cement-solidified soil, whereas the internal friction angle increased by 5.1°. At a solidifying age of 14 d, the penetration resistance almost doubled, indicating a significant improvement in the bearing capacity of the soil. The results suggest that modified lignin-based admixtures may significantly enhance the performance of cement-solidified soil. The cement curing admixture used in this study provides theoretical and technological support for curing agent preparation and the utilization of slag.

Building sustainable and affordable transport systems is a key issue for social development and sustainable urban expansion. The study used dynamic ordinary least squares (DOLS) and fully modified ordinary least squares (FMOLS) to examine the impact of transport infrastructure investment on environmental degradation in China, Japan, and South Korea over the period 1995–2020 and the validity of the EKC hypothesis. The results show that GDP has a significant positive effect, and GDP2 and GDP3 have significant adverse effects on environmental degradation, respectively. These results confirm the validity of the inverted U shaped EKC hypothesis in selected Asian countries. Road infrastructure investment has a significant positive effect, while railway infrastructure investment has a significant adverse effect on environmental degradation. Air infrastructure investment and trade opening have a progressive and statistically significant impact on environmental pollution. Modern rail systems that run on electricity are considered less polluting, so the share of rail infrastructure investment in the transport mix can help build sustainable and safe transport systems at the city Centre and intercity levels and reduce emissions in Asian countries. Moreover, strict enforcement of the prevailing environmental conditions of trade agreements should be encouraged to reduce the increasing impact of free trade on environmental pollution.

High enthalpy stagnation gas can be converted into hypervelocity flow through the contraction—expansion nozzle. The enthalpy flow in the nozzle can be divided into three regions: an equilibrium region, a non-equilibrium region, and a frozen region. The stagnation gas with a total enthalpy of 13.4 MJ/kg is used to analyze the thermochemical non-equilibrium effects. At the selected conditions, the effects of a conical nozzle under different expansion angles of the expansion section, curvature radius of the throat, throat radius, and convergence angle of the convergent section are investigated. Based on the Spalart–Allmaras one-equation turbulence model with the Catris–Aupiox compressibility correction, a multi-block solver for axisymmetric compressible Navier–Stokes equations is applied to simulate the thermochemical non-equilibrium flow in several high enthalpy conical nozzles. The multi-species two-temperature equation is employed in the calculation. The results reveal three interesting characteristics: Firstly, the thermochemical non-equilibrium effects are sensitive to the maximum expansion angle and throat radius but not to the radius of throat curvature and contraction angle. Secondly, as the maximum expansion angle decreases and the throat radius increases, the flow approaches equilibrium state. When the maximum expansion angle decreases from 12° to 4°, the freezing temperature decreases from 2623 K to 2018 K. When the throat diameter increased from 10 mm to 30 mm, the freezing temperature decreased from 2442 K to 2140 K. Finally, the maximum expansion angle and throat radius not only affect the position of the freezing point but also the flow field parameters, such as temperature, Mach number, and species mass fraction.

Abstract Background The primary aim of this study was to observe the effect of 5-ALA-mediated photodynamic therapy on oral squamous cell carcinoma in vitro. Methods SCC25 cells were divided into the observation group and the blank control group. Different concentrations of 5-ALA and SCC25 cells were co-incubated for different times, and the concentration of protoporphyrin IX was detected by flow cytometry. SCC25 cells were divided into the 5-ALA group (100 mg/L), the laser irradiation group alone, the 5-ALA plus laser irradiation group, and the blank control group (0 mg/L 5-ALA), and the methyl thiazolyl tetrazolium (MTT) solution method was used (each group was incubated for 4, 8 and 12 h in turn). The cell survival rate was calculated. Using annexin V-fluorescein isothiocyanate/propidium iodide method, the apoptosis of SCC25 cells was detected by flow cytometry. Results The level of protoporphyrin IX in SCC25 cells increased with increased concentrations of 5-ALA and length of incubation. However, after 12 h, protoporphyrin IX level in SCC25 cells was gradually stabilized, and similar effect was obtained with 100 mg/L or more 5-ALA, indicating that the level of protoporphyrin IX in SCC25 cells was determined by 5-ALA concentration and incubation time. 5-ALA plus laser irradiation exerted an inhibitory effect on the growth of SCC25 cells, which was highly associated with drug dose and incubation time. Compared with the control group, laser irradiation alone or 5-ALA alone had no effect on the apoptosis of SCC25 cells. Different concentrations of 5-ALA combined with laser irradiation showed a remarkable effect of apoptosis, and a higher apoptosis rate was seen with higher drug concentrations. Conclusion 5-ALA-mediated photodynamic therapy affects the growth of SCC25 cells in vitro, which may provide a new idea for the clinical treatment of oral squamous cell carcinoma.

Abstract The high enthalpy nozzle converts the high enthalpy stagnation gas into the hypervelocity free flow. The flow region of the high enthalpy nozzle consists of three parts: an equilibrium region upstream of the throat, a non-equilibrium region near the throat, and a frozen region downstream of the throat. Here we propose to consider the thermochemical non-equilibrium scale effects in the high enthalpy nozzle. By numerically solving axisymmetric compressible Navier-Stokes equations coupling with Park’s two-temperature model, the fully non-equilibrium solution is employed throughout the entire nozzle. Calculations are performed at different stagnation conditions with the different absolute scales and expansion ratio. The results of this study are twofold. Firstly, as the absolute scale and expansion ratio increase, the freezing position is delayed, and the flow approaches equilibrium. Secondly, the vibrational temperature and Mach number decrease with the increase in the nozzle scale and expansion ratio, while the speed of sound, static pressure, and translational temperature increase as the nozzle scale and expansion ratio increase.

This paper presents the design and process of two highly sensitive sensors working in the terahertz band. The sensors comprise the quartz substrate, medium, reflection plate, and metal resonant layer with a symmetrical single-slot patch array. The devices help study the electrically induced permittivity of two liquid crystals in different frequency bands and at different voltages, and the experimental data verify that both liquid crystals have a large birefringence. Based on experimental results, the sensitivity of the fabricated sensor is 47.03 GHz/RIU in the frequency range 90–140 GHz. Similarly, the other fabricated sensor has a sensitivity of 112.47 GHz/RIU in the frequency range 325–500 GHz. The results show that both sensors have superior sensing properties and potential applications in biological and chemical liquid sensing.

In this work, the tensile responses of 3D woven quartz fiber silica matrix composites were experimentally and numerically investigated. The ceramic composites reinforced by 3D layer-to-layer angle interlock woven preforms were manufactured and tested under warp direction tension. A numerical method is proposed to model the mechanical response of the ceramic composites under tension. The method is based on a mesoscopic single layer unit cell for the composites, using a progressive damage analysis approach to account for damage evolution. The predicted results are compared with experimental data, and good agreement in the stress–strain response up to the ultimate tensile strength of the composites is obtained. It has been demonstrated that the proposed numerical model based on a simple single layer unit cell is both efficient and effective in characterization of the mechanical behavior of the 3D layer-to-layer woven ceramic composites.

It is well-known that the quantum efficiency (QE) of inverted AlGaInP solar cells is less than that of upright ones, and the mechanism has not been well-explained. In this paper, a Si-doped AlInP window layer, compared with an emitter layer, is revealed to be one more important factor that decreases QE. It is noted that the quality of a heavily Si-doped AlInP window layer would decrease and further deteriorate subsequent active layers. An optimization strategy of a Si-doped AlInP window layer is proposed, which proves effective through time-resolved photoluminescence measurements (TRPL) of double heterojunctions. Inverted 2.1 eV AlGaInP solar cells with an improved AlInP window layer are fabricated. A 60 mV Voc increment is achieved with a remarkable enhancement of the fill factor from 0.789 to 0.827. An enhanced QE of 10% to 20% is achieved at short-wavelength and the peak IQE rises from 83.3% to 88.2%, which presents a nearly identical IQE compared with the upright reference. Further optimization in GaAs homojunction sub-cells is performed by introducing an n-GaInP/p-GaAs heterojunction structure, which decreases the recombination loss in the emitter caused by a poor AlInP window layer. The optimized structure significantly improves the Voc of the inverted GaAs-based T-3J solar cells to 3830 mV, boosting the efficiency of SBT five-junction solar cells to 35.61% under AM0 illumination.

In this article, we present a study of the equivalent dielectric constant of two nematic liquid crystals (LCs) with different thicknesses, in the region from 90 to 140 GHz. The equivalent dielectric constant of the LCs was measured using a frequency selective surface (FSS). The LC-based tunable FSS with 22 × 25 unit cells was printed on a quartz substrate with an area of 4 × 4 cm2 and a thickness of 480 µm; the LC layer with thicknesses ranging from 30 to 100 µm acted as a substrate. The FSS featured a maximum frequency-shifting range of 8.15 GHz and 30 µm-thick LC layers with mutually orthogonal rubbing directions were deposited on it. The results show that the initial equivalent dielectric constant of the LC layer increased with the LC layer thickness, while the saturation-equivalent dielectric constant remained almost constant. This work provides LC parameters that can be useful for the design of LC-based devices in the millimeter and terahertz ranges.

Radiation-induced defects are responsible for solar cell degradation. The effects of radiation and annealing on the defects of a GaAs/Ge solar cell are modeled and analyzed in this paper. The electrical performance and spectral response of solar cells irradiated with 150 keV proton are examined. Then, thermal annealing was carried out at 120°C. We found that the proportion of defect recovery after annealing decreases with increasing irradiation fluence. The minority carrier lifetime increases with decreasing defect concentration, which means that the electrical performance of the solar cell is improved. We calculated the defect concentration and minority carrier lifetime with numerical simulation and modeled an improved annealing kinetic equation with experimental results.

In this paper, we demonstrate a frequency shifter at 780 nm based on an X-cut Z -propagating lithium niobate waveguide platform with an isotropic orientation. The electro-optic effect modulates the signal with traveling-wave configuration. The frequency-shifting device emulates a rotating half-wave plate when it converts left circular polarized input light to right circular polarized output light and changes the original optical frequency by its modulation frequency. We characterize the device by conducting the polarization conversion experiment and achieve the frequency shift at up to 2 GHz and more than 20 dB extinction ratio. The device needs 30 dBm RF power to perform a frequency shift with high extinction ratio. With the same device, we also demonstrate optical isolation with 18.5 dB extinction ratio.

It is highly desired that synthesis of photothermal agents with near-infrared (NIR) absorption, excellent photostability, and high photothermal conversion efficiency are essential for potential applications. In this work, three (D-A) conjugated polymers (PBABDF-BDTT, PBABDF-BT, and PBABDF-TVT) based on aza-heterocycle, bis(2-oxo-7-azaindolin-3-ylidene)benzodifurandione (BABDF) as the strong acceptor, and benzodithiophene-thiophene (BDTT), bithiophene (BT), and thiophene-vinylene-thiophene (TVT) as the donors, were designed and synthesized. The conjugated polymers showed significant absorption in the NIR region and a maximum absorption peak at 808 nm by adjusting the donor and acceptor units. Their photothermal properties were also investigated by using poly(ethylene glycol)-block-poly(hexyl ethylene phosphate) (mPEG-b-PHEP) to stabilize the conjugated polymers. Photoexcited conjugated polymer (PBABDF-TVT) nanoparticles underwent non-radiative decay when subjected to single-wavelength NIR light irradiation, leading to an excellent photothermal conversion efficiency of 40.7%. This work indicated the aza-heterocycle BABDF can be a useful building block for constructing D-A conjugated polymer with high conversion efficiency.

In the previous work, two new nematic liquid crystal (NLC) mixtures, E7-2 and S200-2, were produced by adding eight LC monomers to two commercial LCs S200 and E7, respectively. At λ = 589 nm, the birefringence (Δn) characteristics of the two LC nematic mixtures E7-2 (Δn = 0.260) and S200-2 (Δn = 0.298) are greater than those of the commercial LC E7 (Δn = 0.224) and S200 (Δn = 0.266). The properties (TN-I, ε//, Δɛ, K11, and K33) of these four NLCs were measured. A double-layer metal loop arrays modulation structure based on metamaterial (MM) metal−dielectric−metal (MDM) was designed and fabricated for use in the THz frequency range. The results show that the LC mixtures E7-2 and S200-2 have greater modulation depth (MD) and less modulation insertion loss (IL) than E7 and S200 at THz frequencies. The results show that LC mixtures have significant potential for designing active tunable LC-based devices in the THz and visible light range.

An electrically tuned phase shifter based on the single slot unit cell and liquid crystal for a reconfigurable reflectarray antenna was presented. The simulation and measured results obtained at the F-band were used to demonstrate that the dielectric properties of a nematic state liquid crystal could be exploited to realize a slot unit cell phase shifter for the reconfigurable reflectarrays antennas. By reducing the inhomogeneous of the external electric field in the liquid crystal layer, a lower control voltage and improved model accuracy was obtained. In the experiments test, the achieved saturation bias voltage (10 V) was smaller than the previously reported structure, and the phase shift of the reflectarray greater than 300° was achieved in the frequency range 121.5⁻126 GHz. The maximum phase shift of 306° occurred at 124.5 GHz.

This paper introduces a tunable metamaterial absorber (MA) based on polymer network liquid crystal (PNLC) in the terahertz (THz) frequency band. Under the optimal polymerization condition, through electrical control of the orientation of the PNLC embedded in the frequency selective surface, the resonant frequency of the absorber can be tuned from 416.5 to 405.0 GHz, corresponding to fractional frequency bandwidth of 2.8%. The experimental results show that the proposed MA based on the PNLC offers an adjustment time of 10 ms and recovery time of 85 ms, which is significantly faster than the tunable metamaterial devices based on conventional nematic liquid crystal (LC).

We present a wideband metamaterial (MM) filter based on a metal-dielectric-metal (MDM) structure. The proposed structure consists of a quartz dielectric substrate and two metallic square-loop arrays, which were deposited on both surfaces of the substrate. The performance of the proposed design was numerically simulated by considering the angle of incidence. The surface current and electric field distributions were calculated for the two resonant frequencies to examine the intrinsic mechanism of the proposed filter. The transmittance of the structure for various oblique angles of incidence was also analyzed. It is generally challenging to completely align the two metallic layers due to limitations in the manufacturing process. Hence, the influence of periodic misalignment on wave propagation was studied. Furthermore, a prototype of the proposed structure was fabricated and the transmission spectra were measured. Simulation and experimental results reveal that our proposed filter can achieve wideband transmission in the F-band. This work is valuable for the design of broadband filters in millimeter and terahertz waves.

We previously demonstrated vast expansion of hypoxic areas in the leukemic microenvironment and provided a rationale for using hypoxia-activated prodrugs. PR104 is a phosphate ester that is rapidly hydrolyzed in vivo to the corresponding alcohol PR-104A and further reduced to the amine and hydroxyl-amine nitrogen mustards that induce DNA cross-linking in hypoxic cells under low oxygen concentrations. In this phase I/II study, patients with relapsed/refractory acute myeloid leukemia (n=40) after 1 or 2 prior treatments or acute lymphoblastic leukemia (n=10) after any number of prior treatments received PR104; dose ranged from 1.1 to 4 g/m2. The most common treatment-related grade 3/4 adverse events were myelosuppression (anemia 62%, neutropenia 50%, thrombocytopenia 46%), febrile neutropenia (40%), infection (24%), and enterocolitis (14%). Ten of 31 patients with acute myeloid leukemia (32%) and 2 of 10 patients with acute lymphoblastic leukemia (20%) who received 3 g/m2 or 4 g/m2 had a response (complete response, n=1; complete response without platelet recovery, n=5; morphological leukemia-free state, n=6). The extent of hypoxia was evaluated by the hypoxia tracer pimonidazole administered prior to a bone marrow biopsy and by immunohistochemical assessments of hypoxia-inducible factor alpha and carbonic anhydrase IX. A high fraction of leukemic cells expressed these markers, and PR104 administration resulted in measurable decrease of the proportions of hypoxic cells. These findings indicate that hypoxia is a prevalent feature of the leukemic microenvironment and that targeting hypoxia with hypoxia-activated prodrugs warrants further evaluation in acute leukemia. The trial is registered at clinicaltrials.gov identifier: 01037556.

To meet the requirements for rapid tumor growth, a complex array of non-neoplastic cells are recruited to the tumor microenvironment. These cells facilitate tumor development by providing matrices, cytokines, growth factors, as well as vascular networks for nutrient and waste exchange, however their precise origins remain unclear. Through multicolored tissue transplant procedures; we have quantitatively determined the contribution of bone marrow-derived and adipose-derived cells to stromal populations within syngeneic ovarian and breast murine tumors. Our results indicate that subpopulations of tumor-associated fibroblasts (TAFs) are recruited from two distinct sources. The majority of fibroblast specific protein (FSP) positive and fibroblast activation protein (FAP) positive TAFs originate from mesenchymal stem/stromal cells (MSC) located in bone marrow sources, whereas most vascular and fibrovascular stroma (pericytes, α-SMA(+) myofibroblasts, and endothelial cells) originates from neighboring adipose tissue. These results highlight the capacity for tumors to utilize multiple sources of structural cells in a systematic and discriminative manner.

Recent studies indicate that interactions between leukemia cells and the bone marrow (BM) microenvironment promote leukemia cell survival and confer resistance to anti-leukemic drugs. There is evidence that BM microenvironment contains hypoxic areas that confer survival advantage to hematopoietic cells. In the present study we investigated whether hypoxia in leukemic BM contributes to the protective role of the BM microenvironment. We observed a marked expansion of hypoxic BM areas in immunodeficient mice engrafted with acute lymphoblastic leukemia (ALL) cells. Consistent with this finding, we found that hypoxia promotes chemoresistance in various ALL derived cell lines. These findings suggest to employ hypoxia-activated prodrugs to eliminate leukemia cells within hypoxic niches. Using several xenograft models, we demonstrated that administration of the hypoxia-activated dinitrobenzamide mustard, PR-104 prolonged survival and decreased leukemia burden of immune-deficient mice injected with primary acute lymphoblastic leukemia cells. Together, these findings strongly suggest that targeting hypoxia in leukemic BM is feasible and may significantly improve leukemia therapy.

Photoresponsive cholesteric liquid crystals (CLCs) can selectively reflect colors upon exposure. However, achieving simultaneous erasure rewriting and color tuning in CLCs through light exposure remains a formidable challenge. Interestingly, CLCs doped with azobenzene show rapid RGB color shifts when exposed to 365 nm wavelength light within a few seconds. This fully reversible process is also easily attainable under 405 nm wavelength irradiation. Furthermore, intense light induces isomerization in the azobenzene molecules, disrupting the molecular arrangement of the liquid crystals and facilitating the transition from a planar state (P-state) to a focal conic state (FC-state). This transition leads to the complete elimination of reflected colors in CLCs. Alongside mechanical stress and electrical responsiveness, these properties make CLCs doped with azobenzene highly attractive and applicable in diverse areas such as color displays, information encryption, and anti-counterfeiting. [ABSTRACT FROM AUTHOR]