Zone Method Research Articles

Thermal insulation of military boots using a thermal foot manikin in cold environments

The purpose of this study was to investigate the thermal insulation of military boots using a thermal foot manikin, and to examine environmental and technical factors to determine their thermal insulation. Three Korean and four US military boots were chosen along with four occupational boots. All measurements were conducted at air temperatures of 21, 0, and − 5 °C with an airflow of < 0.15 m s−1. The following two calculations of thermal insulation were compared: (1) a method using values obtained from all nine zones of the foot manikin [entire-zone method], and (2) a method using values from only zones covered by the boot [partial-zone method]. The results showed that the total insulation (IT) of the 11 protective boots ranged from 0.9 to 1.2 clo per boot and no differences in thermal insulation across the three air temperatures were found. Thermal insulation had a significant and strong relationship with the thickness of the boot layer (r = 0.905, P < 0.001), whereas there was no relationship between the thermal insulation and the boot mass. The thermal insulation of military boots was 81% explained by the thickness of the boot layer alone, and 94% by both the thickness of the boot layer and boot mass (P < 0.001). Thermal insulation based on the partial-zone method was 26% greater than the values using the entire zone method. We proposed design strategies for military boots according to zonal power consumption.

Ecological Management Zoning Identification by Coupling Blue-Green and Gray Infrastructure Networks: A Case Study of Guizhou Province, China

Ecological management zoning is crucial for maintaining regional ecological security and realizing differentiated urban ecological governance. However, the existing zoning methods are overly focused on ecological functional attributes and fail to adequately consider the impacts of human activities, resulting in an insufficiently rational allocation of resources. Taking Guizhou Province as an example, using multi-source data and spatial analysis tools, this study proposed an ecological management zoning framework based on the coupling analysis of the blue-green infrastructure (BGI) network and gray infrastructure (GI) network. The results indicated that (1) the BGI network in the study area included 179 sources, with a total area of 54,228.80 km2, and 232 corridors. (2) There were 53 sources in the GI network, totaling 709.19 km2, and the corridors of the first, second, and third levels were 11,469.31 km, 6703.54 km, and 5341.30 km, respectively. (3) There were 606 barrier points identified, mainly distributed in the central part of the study area, and the total area of the disturbance zone was 1132.50 km2, which had the largest distribution in Qiandongnan, followed by Qiannan. (4) At the county scale, five ecological management zones were identified in the study area based on four indicators, namely, the source area ratio of BGI network, corridor density of BGI network disturbance zone area ratio, and density of barrier point. Then, we proposed targeted optimizations and restorations for each zone. This study organically linked ecological functional attributes and anthropogenic impacts to identify ecological management zones, which will provide new perspectives on synergies between ecological protection and economic development.

Revalidation and optimization of NPK nutrients in tomato (Lycopersicon esculentum mill) under furrow irrigation method in northern dry zone of Karnataka

Revalidation and optimization of NPK nutrients in tomato (Lycopersicon esculentum mill) under furrow irrigation method in northern dry zone of Karnataka

ПРИМЕНЕНИЕ CОЛЯНО-КИCЛОТНОЙ ОБРAБОТКИ ПРИЗAБОЙНЫХ ЗОН CКВAЖИН

One of the main tasks in the development of oil fields is to extract as much of the natural oil reserves from the earth's subsurface as possible. The increase in the ultimate oil recovery from the developed reservoirs and the enhancement of oil production rates are largely achieved through the widespread introduction of oil production intensification methods. The need to apply various methods of impacting the wellbore zone is primarily due to the imperfections in drilling methods used to open productive formations. This is especially true for formations with poor reservoir properties and low formation pressure. The less the permeability of the wellbore zone deteriorates during drilling, the less the need arises to use wellbore treatment methods. These methods have been applied in nearly all gas condensate reservoirs in Kazakhstan, Russia, and CIS countries with carbonate reservoirs. The primary acid used in the acid treatment of reservoirs is hydrochloric acid (HCl). The article presents the features and criteria for the application of the hydrochloric acid treatment method in the wellbore zone.

Dynamic Characteristics of Gear System Under Compound Fault of Tooth Root Crack and Bearing Outer Ring

Research on single faults like tooth root cracks and bearing outer ring failures is well-established. However, existing studies often replace the actual crack propagation path with a simplified linear crack model, neglecting the variation in stress intensity factors. They do not account for the coupling effect between gear teeth when calculating gear mesh stiffness. In practice, gearbox failures are predominantly compound failures involving both gears and bearings. This paper simulates the actual crack propagation path based on Workbench, introduces a dual-tooth meshing zone method to address the tooth-to-tooth coupling effect, and establishes a dynamic model of a system with compound faults of tooth root cracks and bearing outer ring defects. The dynamic response of the system under different levels of deterioration is then investigated. The findings indicate that the crack propagation path exhibits a concave shape, with the curvature of the path increasing as the crack deteriorates. The time-varying mesh stiffness calculated by considering tooth-to-tooth coupling effects aligns more closely with the finite element results. By analyzing the evolution patterns of the impact components and sidebands during the deterioration process, the dynamic evolution trends of the coupling phenomenon between tooth root cracks and bearing outer ring faults are clarified.

Growth and Inelastic Light Scattering Studies on Sr2Nb2O7 Single Crystal

AbstractA crack‐free and high structural quality Sr2Nb2O7 single crystals are grown by the optical float zone method using optimized growth parameters. The Laue pattern confirms the single crystalline nature of the grown crystal. Temperature‐dependent Raman and Brillouin light scattering studies reveal a significant shift in phonon modes across normal to incommensurate phase transition (Tn‐in) which occurs ≈488 K. In the temperature range from 900 down to 500 K, two optical phonon modes ≈63 (B1 mode) and 54 cm−1 (A1 mode) are observed. The frequency of A1 mode strongly decreases with an increase in temperature above the Tn‐in while the frequency of this mode almost remains constant below the Tn‐in. In contrast, the frequency of B1 phonon mode is found to increase with temperature in the range of 500–900 K but it does not display a significant shift below the phase transition temperature. In addition, in the in‐commensurate phase (T&lt; 488 K), a new optical phonon mode (M1) at ≈35 cm−1 also begins to appear and exhibits strong stiffening behavior with an increase in temperature in the range of 300–488 K. Moreover, the anomalous behavior of the acoustic phonon across Tn‐in are further probed using Brilliouin scattering. Longitudinal acoustic phonon mode at 41 GHz exhibits a strong change in slope near Tn‐in. In addition, the transverse acoustic modes at 28.6 and 22.4 GHz also exhibit strong anomalies with minimum frequency near Tn‐in. The inelastic light scattering studies provide valuable information on the phase transition.

Comparison of Collision Avoidance Algorithms for Unmanned Surface Vehicle Through Free-Running Test: Collision Risk Index, Artificial Potential Field, and Safety Zone

This paper details the development of a collision avoidance algorithm for unmanned surface vehicles (USVs) and its validation using free-running tests. The USV, designed as a catamaran, incorporates a variety of sensors for its guidance, navigation, and control system. It performs turning maneuvers using thrusters positioned on the port and starboard sides. The robot operating system is used to streamline communication, transmitting data such as position, orientation, and situational information from diverse sensors. Using the collision risk index (CRI) method, the algorithm calculates risk based on the distance to obstacles and the angle to the desired waypoint, directing the USV on a path with minimized risk. Noise within the data captured by the two-dimensional light detection and ranging system is filtered out using the k-dimensional tree and Euclidean distance methods, ensuring single obstacles are distinctly identified. To assess the efficacy of the CRI-based collision avoidance algorithm, it was benchmarked against other algorithms rooted in the artificial potential field and safety zone methods within an artificial tank setting. The results highlight the CRI method’s superior time efficiency and optimality in comparison to its counterparts.

Effect on In3+ co-doping on photoluminescence and scintillation properties of LYSO:Ce crystal

In this work, a series of LYSO:0.03 at.% Ce,xat.%In (x = 0, 0.001, 0.005 and 0.01) crystals were successfully grown for the first time by the optical floating zone (FZ) method. The effect of In3+ co-doping on photoluminescence and scintillation properties of LYSO:Ce scintillation single crystal was investigated. It was found that at x = 0.001, the overall scintillation performance was optimized. This was attributed to the fact that In3+ co-doping reduces the concentration of Ce2 emission center and accelerates the photoluminescence decay time of Ce3+. The temperature dependence of photoluminescence of LYSO:Ce,xat.%In samples was also investigated. Combined with density functional theory calculation, the phenomenon of In3+ co-doping leading to a decrease in quenching temperature of decay time was explained in terms of both crossover relaxation and introduction of impurity energy levels.

Marginalization of urban space: Experience of sociological research on the example of Khabarovsk

The object of this study is the process of marginalization. The subject is the marginalization of urban space. The aim of the paper is to actualize and clarify the essence of the process of urban space marginalization, as well as to identify the features of urban space marginalization using the example of Khabarovsk. The article employs methods of scientific-theoretical analysis, generalization, and systematization of domestic and foreign research on marginalization problems, as well as empirical methods such as surveys, expert interviews, and the method of vernacular zoning. The theoretical part of the article demonstrates a multitude of different approaches to defining marginality and marginalization, on the one hand, and the lack of stable definitions of these concepts, on the other. This is primarily explained by the lack of a comprehensive approach to the study of the marginalization process. To provide a more complete definition of the process of urban space marginalization, the article applies an algorithm: causes - essence - implementation - consequences. The practical significance of studying the marginalization of urban spaces is determined by the need to control marginal areas in terms of the spread of various social deviations, as well as the need to forecast marginalization trends. Based on empirical studies of urban space (using the example of Khabarovsk), the study of public and expert opinions, and the use of the method of vernacular zoning, the overall "well-being" of different vernacular districts of the city was determined, the level of income of city residents living in these districts was assessed, the correlation between the determination of the level of "well-being" and the crime rate of the district was revealed, as well as the features of the stigmatization of urban spaces, which is an integral part of the process of marginalization.

A037: The Influence of Absolute-Speed Training Under Long-Jump in Take-Off Area on Run-Up Performance and Results

Purpose: Recently, the IAAF put forward the idea of changing the long jump to the starting area, and the implementation of this rule will inevitably change the training strategy of the long jump event. Compared with pedal take-off, the speed of running under the take-off zone rule has a greater impact on performance. Therefore, this study adopted the measurement methods of take-off zone and take-off board. The take-off zone was to take the take-off position in the area as the starting point for measuring the long jump distance. Compared with the traditional pedal take-off, the difference in the run-up performance and results of absolute speed training under these two take-off methods were analyzed. Method: In this study, 16 student-athletes were divided into the area group and the board group by the method of literature, experiment and video analysis. Before and after the intervention, three times a week for eight weeks, the 30-meter run, the 30-meter run between marching, the standing long jump and the long jump were tested. The average speed of the last 5 meters and the last 5-10 meters of the long jump run-up were collected and the differences before and after the experiment were compared. Results: (1) Both the 30-meter run and the 30-meter run between the two groups improved, and the standing long jump performance did not change significantly. (2) There were no significant differences in the speed of the last 5-10 meters of the run-up between the two groups, but the speed of the last 5 meters of the board group decreased significantly along with decreased stride length (p &lt; 0.01). (3) The speed of the last 5 meters and the last 5-10 meters in the zone group did not change and the stride length was average. Discussion: (1) For the starting area long jump, absolute speed training can improve performance. However, the effect is not satisfactory in the springboard long jump, because the stride length and rhythm change with speed. (2) In the starting board long jump in the speed training at the same time with the run-up rhythm of training to achieve the best results. (3) If the IAAF promotes the starting area long jump, athletes with strong speed will have greater advantage, while "technical" athletes who rely on pedal accuracy may face greater challenges.

Typology Visual Guidelines for Transit-Oriented Development 3-D Incentive Zoning in East Asian Metropolitan Cities—A Case Study of Shanghai Subway-Adjacent Plots

The revitalization and renewal of existing urban space is a primary objective in the redevelopment of high-density transit-oriented development (TOD) areas. In this context, offering incentive zoning bonuses is a critical tool for optimizing urban space. However, in some subway-adjacent plots with high building densities, traditional incentive zoning methods face limitations due to insufficient horizontal space. These areas increasingly rely on multi-ground public spaces to balance density with public services. This study investigates new methods of incentive zoning between commercial areas and public spaces in multi-ground public spaces within subway-adjacent plots, using 33 rail transit complexes in Shanghai, China, as the research subject. The findings are presented in the form of visual guidelines to provide guidance on architectural control, with the goal of enhancing the quality of urban public spaces. In this research, a multiple linear regression model is employed, using GNCS_AR (the ratio of ground non-commercial stay to area), which captures both efficiency and equity in public space quality, as the dependent variable. A model is developed in SPSS, incorporating independent variables such as TCA (total commercial area), POS (public open space area), PIS (public indoor space area), and MGZFs (multi-ground zoned floors). This model provides a framework for developers to manage and control public space in multi-ground settings within rail transit complexes. Research has found that MGZFs alone cannot be included as the independent variable in the model, as their absence leaves the model unable to explain three-dimensional spaces. However, incorporating the ratio of RIOPS (the ratio of indoor to outdoor public space) to MGZFs significantly improves the model’s correlation and explanatory capacity. The resulting model demonstrates that, under different POS and MGZF tiers, the influence of PIS and TCA on public space quality varies. Using a typological approach, the study categorizes these complexes into five tiers based on POS and MGZFs. Within the same tier, changes in PIS and TCA types lead to variations in public space quality. The empirical results are translated into diagrams that link data, forms, and indicators to guide the development of three-dimensional spaces. These diagrams, which can be named visual guidelines, provide practical guidelines for optimizing public spaces in these subway-adjacent plots.

High-precision roundness measuring system for tungsten ball tips with the diameter of less than 100 µm

Abstract Tungsten balls with a diameter of less than 100 μm can function as probe tips for micro-coordinate measuring machines to measure ultraprecise workpieces with complex features. A high-precision measuring system was developed to evaluate the roundness of self-made tungsten ball tips. The system, based on the two-point method, is composed of two oppositely placed interferometers and a turntable. The turntable rotates the tested ball, and the interferometers measure the variation in radius. A new model based on the minimum zone method is proposed to evaluate roundness. The fabrication principle of tungsten balls is introduced and an analysis is conducted on the maximum permissible contact force and bending stress of tungsten ball tips. The elastic mechanism is designed, based on the analysis. A ruby sphere with a sphericity of 130 nm is measured to verify the system’s effectiveness. Repeated experiments are performed for two tungsten ball tips. The results show that the roundness error of tungsten ball-A is between 550.9 and 586.2 nm with a standard deviation of 11.0 nm while tungsten ball-B’s roundness error is between 898.5 and 959.9 nm with a standard deviation of 21.7 nm. The uncertainty is calculated as 144.6 nm. The developed system can stably measure the roundness of tungsten ball tips.

Luminescence properties of β-Ga2O3:Bi single crystals growth by the optical floating zone method

β-Ga2O3, an advanced semiconductor optical material, exhibits remarkable luminescence properties through doping. In this study, β-Ga2O3:Bi single crystals were successfully grown using the optical floating zone method, and their luminescence mechanisms were investigated. Our results demonstrate that reducing the sintering temperature to 1000 °C enhances the incorporation of Bi into the crystal matrix. Temperature-dependent spectral analysis reveals the non-radiative transitions in the blue light region, contributing to fast luminescence dynamics. These findings deepen our understanding of the luminescence characteristics of β-Ga2O3 single crystals and provide valuable insights for potential applications in radiation detection.

Fatigue life prediction of hybrid carbon-flax-epoxy laminates using progressive failure analysis and cohesive zone model

A 3D progressive fatigue damage model was incorporated into ABAQUS software to predict the fatigue life of hybrid carbon-flax-epoxy composites. A cohesive zone method was employed to simulate delamination damage at carbon/flax interface. To evaluate the accuracy of the finite element model, two different layups, namely, unidirectional [0–90C2/0 F6]S (UD) and angle-ply [0–90C2/(±45) F6]S (AP), consisting of 12 flax fibers layers (F) sandwiched between four woven carbon fibers layers (C) were created using hand lay-up technique and then placed in compression molding. There is a good agreement between experimental and predicted fatigue life. It was observed that the predicted fatigue life is reduced by about 14% by changing the void content from 0.38% to 3.83%. The finite element analysis revealed that the matrix in the flax region of the AP layup failed at 12% of fatigue life, followed by delamination at the carbon/flax interface, consistent with SEM results.

(Invited) Photoluminescence and Scintillation Properties of Heavy Single Crystal Scintillators for X- and Gamma-Ray Detection

Scintillators are one of the luminescent materials, and have a function to convert a quantum of ionizing radiation to thousands of low energy photons immediately via interactions between the material and ionizing radiation [1,2]. Generally, scintillators are combined with photodetectors, and when the scintillation photons are emitted from the scintillator, photodetectors convert them to electrical signals. When the target ionizing radiation is high energy photons such as X- and gamma-rays, heavy materials are preferable for scintillators since the detection efficiency against high energy photons depends on density and effective atomic number. Up to now, many types of materials have been examined for scintillators, such as single crystals, glasses, and opaque and transparent ceramics [2]. Among them, bulk single crystalline scintillators have been applied for scintillation detectors owing to a superior optical quality including high transmittance and luminescence efficiency.In the conference, some recent results of development of heavy scintillators mainly containing Lu, Hf, Ta and Tl are introduced. These materials were synthesized by some single crystal growth techniques such as the floating zone and bridgman method. After the synthesis, they were examined on optical (photoluminescence excitation and emission spectra and decay curve) and scintillation (scintillation emission spectrum, decay curve, afterglow and pulse height) properties. In Lu-based crystals, rare earth doped Lu2O3 crystals are introduced, and especially, Tb- and Eu-doped ones show a high scintillation light yield. In Hf-based ones, some results of rare earth doped AEHfO3 (AE = alkali earth) crystals are presented, and Ce-doped (Mg,Ca)HfO3 shows a high scintillation light yield [3]. Among Ta-based crystals, Mg4(Nb,Ta)2O9 crystals have a high light yield due to charge transfer luminescence of Ta/Nb and O [4]. In Tl-based crystalline compounds, TlMgCl3 shows a high light yield and energy resolution [5]. In the conference, these results will be introduced.

Traveling Solvent Floating Zone Growth and Ionic Conductivity of Li0.1La0.3Nb0.8Ta0.2O3 Single Crystals

Li x La(1-x)/3Nb1-y Ta y O3 (LLNT) is a solid electrolyte with a double perovskite-type structure. It was reported that the highest ion conductivity of LLNT was 7.78 × 10-5 S/cm at x = 0.1, y = 0.2 [1,2]. Therefore, in this study, we investigated the preparation conditions of the feed and the growth conditions of Li0.1La0.3Nb0.8Ta0.2O3 single crystals by the traveling solvent floating zone (TSFZ) method.Li2CO3, La2O3, Nb2O5, and Ta2O5 were used as starting materials, weighed at Li x La(1-x)/3Nb1-y Ta y O3 (x = 0.1, y = 0.2) stoichiometric composition, and mixed with ethanol. The mixed powder was calcined at 800 °C for 2 hours in air. The calcined powder was grounded and calcined again at 1200°C for 12 hours in air. The calcined powder was then shaped into a cylindrical shape by rubber pressing and sintered at 1350°C for 5 hours in air. Solvent of 5 mol% of La(Nb,Ta)3O9-poor, La(Nb0.5Ta0.5)O4-poor or La(Nb0.8Ta0.2)O4-poor composition relative to the stoichiometric composition of LLNT feeds was prepared using the same procedure as the feed rod preparation. The optical floating zone machine was used for crystal growth. The growth conditions were the growth rate of 2 or 5 mm/h, the growth atmosphere of Ar or N2. The grown crystals were characterized using X-ray diffraction, electron probe micro-analyzer (EPMA), and impedance measurements.As a result of crystal growth of LLNT by the floating zone (FZ) method, the La(Nb,Ta)3O9 phase was deposited as an inclusion in the initial growth region, even though Li evaporation from the molten zone was not observed. This result indicates that LLNT is an incongruently melting compound. Next, the TSFZ method, FZ method using solvents, was applied to the growth of LLNT crystals. La(Nb,Ta)O4 inclusion phase deposited in the initial growth part of the grown crystal when using solvent of 5 mol% La(Nb,Ta)3O9-poor composition relative to the stoichiometric LLNT. In the case of using a 5 mol% La(Nb0.8Ta0.2)O4-poor solvent composition, crystals with a length of 12 mm and a diameter of 5 mm were obtained as shown in Fig. 1(a). La(Nb,Ta)O4 inclusion phase was not detected in the grown crystal. The chemical composition of the LLNT phase was determined to be y = 0.14-0.25 by quantitative analysis using EPMA as shown in Fig. 1(b). Therefore, inclusion-free LLNT crystals were obtained using a solvent with 5 mol% La(Nb0.8Ta0.2)O4-poor composition relative to the stoichiometric LLNT composition. Moreover, the molten zone was stable in Ar gas or N2 gas flow at growth rate of 5 mm/h. The ionic conductivity of the grown crystal was σ= 2.0 ×10-5 S/cm . The low conductivity is due to cracks, and inhomogeneous in the grown LLNT crystal. Optimization of the solvent composition is required for LLNT crystals with homogeneous and high ionic conductivity.References.[1]Y. Maruyama, et. al., J. Ceram. Soc. Jpn. 128, 761-765 (2020). [2]Y. Maruyama, et. al., J. Ceram. Soc. Jpn. 129, 535-539 (2021). Figure 1

Growth of Solid Electrolyte Li1+X Al x Ti2-X (PO4)3 Single Crystals

The bulk single crystals are useful for our understanding of interfacial properties. Single crystals of lithium ion conductor, which can reveal intrinsic electrochemical properties, are an essential material for the development of high-performance all-solid-state lithium-ion secondary batteries. Li1+x Al x Ti2-x (PO4)3 (LATP) has a high ionic conductivity of ~10-3 S/cm at room temperature and show promise for the application of solid electrolyte for all solid-state batteries1, 2). We have tried to grow LATP crystals by floating zone method. Lithium phosphate such as Li4P2O7 evaporated from the molten zone during the crystal growth. As the result, AlPO4 and TiO2 phases precipitated in the LATP grown crystals. Therefore, excessive addition of lithium phosphate into the feeds to compensate for the evaporation component is necessary for LATP crystal growth. Next, we grew LATP crystals using the feed with a Li4P2O7 excess from the LATP composition by the melt slow cooling method. As the result, we have successfully grown LATP single crystals as shown in Fig 1, when the crystals were grown with a molar ratio of LATP : Li4P2O7 = 1 : 1, a maximum temperature of 1400°C, and a slow cooling rate of 5°C/h. The concentration of Al in the grown crystals was x = 0.16, which is approximately half of the feed concentration (x = 0.3). The crystal orientation was [100], and the ionic conductivity was σ[100] = 9.1 × 10-4 S/cm at room temperature.Reference1) H. Aono et al., J. Electrochem. Soc., 137, 4, 1023-1027 (1990).2) Yihzou Zhu et al., J. Mater. Chem. A 4, 3253 (2016). Figure 1

Αlpha-Ray Detection Properties of Spinel Single Crystals

A scintillator is one of the phosphors for radiation detection. Typical application fields of scintillators are medical, security, and environmental dosimetry. In nuclear facilities, there are high doses of α-ray, and monitoring of α-ray is necessary. Up to now, Ag-doped ZnS is used for α-ray detection. Although Ag-doped ZnS has high light yield, the detection efficiency is limited because the material form is opaque polycrystal. Therefore, a novel scintillator with high transparency is required for α-ray detection. Spinel materials are one of the candidates for radiation detection because of their high radiation resistant. According to the previous study, scintillation properties of MgGa2O4 and ZnGa2O4 have been studied under γ-ray irradiation. On the other hand, these materials seem to be suitable for α-ray detection rather than γ-ray detection because of the low effective atomic number. In addition, other spinel materials also worth studying. In this study, we synthesized MgAl2O4, MgGa2O4, ZnAl2O4, and ZnGa2O4 single crystals and evaluated the optical and scintillation properties.The starting powders were MgO, ZnO, Al2O3, Ga2O3. The powders were mixed into homogeneously and shaped into cylindrical rods by packing into balloon and applying hydrostatic pressure. Then, the rods were sintered 1400°C for 8 h in air to obtain ceramics precursor. Single crystalline samples were synthesized by the floating zone method using the ceramics precursor. For measurements, the synthesized crystals were processed to approximately 5 mm in diameter and 1 mm in thickness by cut and polishing.The transparent and single-phase of the MgAl2O4, MgGa2O4, ZnAl2O4, and ZnGa2O4 single crystals were successfully obtained by the floating zone method. According to the total transmission spectra, the total transmittances of the crystals were 70−80% in visible region. In the X-ray-induced scintillation spectra, MgAl2O4, MgGa2O4, ZnAl2O4, and ZnGa2O4 single crystals showed a luminescence peak around 380, 400, 300, and 350 nm, respectively. The luminescence origin of each crystal was considered to be due to oxygen vacancies of the host materials. Figure 1 shows the pulse height spectra of the spinel crystals under 241Am α-ray irradiation. The spectra of a commercial Bi4Ge3O12 (BGO, 8000 ph/MeV) single crystal under 137Cs γ-ray irradiation is also shown as a reference. As shown in Figure 1, all the crystals showed a clear full energy peak. From the comparison with the peak position of BGO, the light yields of the MgAl2O4, MgGa2O4, ZnAl2O4, and ZnGa2O4 single crystals were 200, 4300, 700, 5700 ph/5.5MeV-α, respectively. The details will be discussed in the conference. Figure 1

Synthesis and optical properties of LaSrGaO4:RE3+ (RE = Sm, Eu, Ho) single crystals via optical float zone method

The advancement of synthesis of materials with luminescence properties of lanthanoid ions in various single crystalline host compounds with low phonon energies has facilitated the optimization of numerous materials to meet the specific optical properties required for diverse applications such as new energy resource exploration, light-emitting diodes (LEDs), quantum dot displays, laser technology, sensors, telecommunications, medical diagnostics and more. Enhanced analyses of the luminescence mechanism of lanthanoid ions in various host compounds, which have captivated researchers for many years and culminated in the development of innovative materials for optical applications. To obtain a deeper understanding of the luminescence mechanism of Sm3+, Eu3+, and Ho3+ ions incorporated into the Ruddlesden-Popper-type host compounds (La1-xREx)SrGaO4 (RE = Sm, Eu, Ho and x = 0; 0.05; 0.10) high quality single crystals with homogenous activator distribution grown by the optical floating zone (OFZ) method were examined systematically. X-ray diffraction (XRD) characterization shows that the compound crystallizes in a tetragonal crystal system with the space group I4/mmm (no. 139) with homogenous distribution of the dopants shown via backscattered electron (BSE) imaging. Photoluminescence studies at both 77 K and 298 K reveal that the incorporated lanthanoid ions brightly emit and even show unusual transitions due to the low cutoff phonon energy of the host compound that limits non-radiative loss pathways. Together with a high physical density of ∼6.4 g/cm3, these phosphors could be conceptualized as interesting candidates for X-ray imaging phosphors aiming at high light yields.

In Situ Crosslinked Biodegradable Hydrogels Based on Poly(Ethylene Glycol) and Poly(ε-Lysine) for Medical Application.

Hydrogels have emerged as promising biomaterials due to their excellent performance; however, their biocompatibility, biodegradability, and absorbability still require improvement to support a broader range of medical applications. This paper presents a new biofunctionalized hydrogel based on in situ crosslinking between maleimide-terminated four-arm-poly(ethylene glycol) (4-arm-PEG-Mal) and poly(ε-lysine) (ε-PL). The PEG/ε-PL hydrogels, named LG-n, were rapidly formed via amine/maleimide reaction by mixing 4-arm-PEG-Mal and ε-PL under physiological conditions. The corresponding dry gels (DLG-n) were obtained through a freeze-drying technique. 1H NMR, FT-IR, and SEM were utilized to confirm the structures of 4-arm-PEG-Mal and LG-n (or DLG-n), and the effects of solid content on the physicochemical properties of the hydrogels were investigated. Although high solid content could increase the swelling ratio, all LG-n samples exhibited a low equilibrium swelling ratio of less than 30%. LG-7, which contained moderate solid content, exhibited optimal compression properties characterized by a compressive fracture strength of 45.2 kPa and a deformation of 69.5%. Compression cycle tests revealed that LG-n demonstrated good anti-fatigue performance. In vitro degradation studies confirmed the biodegradability of LG-n, with the degradation rate primarily governing the drug (ceftibuten) release efficiency, leading to a sustained release duration of four weeks. Cytotoxicity tests, cell survival morphology observation, live/dead assays, and hemolysis tests indicated that LG-n exhibited excellent cytocompatibility and low hemolysis rates (<5%). Furthermore, the broad-spectrum antibacterial activity of LG-n was verified by an inhibition zone method. In conclusion, the developed LG-n hydrogels hold promising applications in the medical field, particularly as drug sustained-release carriers and wound dressings.