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1

Modification of Axial Distribution of Fragment Velocity in Preformed Fragmentation Warheads

Li Xin, Wang Weili, Liang Zhengfeng, Dong Jun

Central European Journal of Energetic Materials

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2024

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Vol. 21, no. 1

22--52

EN

Fragment velocity is a crucial parameter for evaluating the destructive capability of a warhead, and it is typically calculated using the Gurney formula with corrections. The currently established correction formulas can determine the axial distribution of natural fragment velocity within the shell, but for a preformed fragmentation warhead, energy losses due to the existence of fragment gaps lead to calculated results that are larger than the actual values, making it unsuitable for accurate calculation of the axial distribution of fragment velocity in such warheads. This paper introduces a filling ratio correction function based on the concept of effective charge and establishes a calculation model for the axial distribution of fragment velocity in preformed fragmentation warheads. The numerical simulation method was validated using prototype ground static explosion test data, then the influence of key parameters such as charge diameter (d), length-diameter ratio (δ), and filling ratio (β) on the axial distribution of fragment velocity was investigated. The relationships between the three parameters (a, m, c) in the filling ratio correction function and the characteristic parameters were derived, and the filling ratio correction function and the calculation formula for the axial distribution of fragment velocity were fitted. Comparisons with existing empirical formulas indicate that the formulas established in this paper offer higher calculation accuracy, with an error of no more than 4.65% compared to measured values, and they can reliably determine the axial distribution of fragment velocity in preformed fragmentation warheads, providing significant practical application value.

2

Sensitivity enhancement of a wavelength interrogation-based optical fiber surface plasmon resonance sensor for hemoglobin concentration using barium titanate

Shi Zhen-Jiang, Guo Shi-Liang, Li Xin, Li Zhi-Quan, Meng Shu-Han, Li Chong-Zhen

Optica Applicata

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2023

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Vol. 53, nr 2

167--184

EN

In this paper, the performances of a wavelength interrogation-based optical fiber surface plasmon resonance sensor for hemoglobin (Hb) concentration is investigated by theoretical simulation. The proposed configuration incorporates optical fiber, 70 nm silver, 18 nm barium titanate (BaTiO3), and 2 nm zinc oxide. Simulation results show the sensor exhibits refractive index sensitivity of 4023 nm/RIU and concentration sensitivity of 10.0873 nm/(g∙dL), along with Hb concentration varying from 0 to 14 g/dL. This paper especially focuses on the influence of BaTiO3 on the performances of the proposed sensor with light wavelength ranging from 350 to 1000 nm. Comparison analysis indicates sandwiching 18 nm BaTiO3 between sensing layers not only enhances the concentration sensitivity by 30.14% but also decreases the nonlinear error of the sensor from 0.68% to 0.63%. For a wavelength accuracy of 0.1 nm, the proposed sensor can provide a resolution of 0.0099 g/dL for Hb concentration detection.

3

Research on characteristics of embedded resonator sensor based on PtS2

Li Xin, Li Xieyuan, Zhang Haitao, Chen Shuang, Liu Shurong, Li Yang

Optica Applicata

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2023

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Vol. 53, nr 2

213--226

EN

An embedded microring resonator model using PtS2 as the core layer was designed and optimized for sensing. The inner layer is made of PtS2, and SiO2 and Si3N4 are used as cladding. The overall structure is Si3N4-SiO2-PtS2-SiO2-Si3N4. Field strength distribution of longitudinal section of single straight waveguide and the longitudinal section of coupling part of straight and annular waveguides are simulated according to the coupled-mode theory. The transfer matrix method is used to analyze characteristics between the length of the U-shaped feedback waveguide and the circumference of microring and the change of attenuation factor and coupling coefficient on the output spectrum. The simulation results showed that the embedded microring resonator with PtS2 as the core presents excellent optical properties. The resonance depth is more than –50 dB, and the sensitivity can reach 1806.61 dB/RIU. When the resonance wavelength is 1550.86 nm and the self-coupling coefficient is 0.9849. The corresponding detection limit is about 1.66056×10–7 dB/RIU, and the quality factor is 2.8848×10–5 under the measurement system with a signal-to-noise ratio of 30 dB. Compared with the traditional single microring structure, the proposed microring presents a higher free spectral range and more suitable for the fabrication of high-sensitivity, low-detection limit, and large-measurement range sensors.

4

A study on the influence of particle size on the identification accuracy of coal and gangue

Li Xin, Wang Shuang, He Lei, Luo Qisheng

Gospodarka Surowcami Mineralnymi

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2023

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T. 39, z. 1

109--129

EN

In order to explore the impact of coal and gangue particle size changes on recognition accuracy and to improve the single particle size of coal and gangue identification accuracy of sorting equipment, this study established a database of different particle sizes of coal and gangue through image gray and texture feature extraction, using a relief feature selection algorithm to compare different particle size of coal and gangue optimal features of the combination, and to identify the points and particle size of coal and gangue. The results show that the optimal features and number of coal and gangue are different with different particle sizes. Based on visible-light coal and gangue separation technology, the change of coal and gangue particle size cause fluctuations in the recognition accuracy, and the fluctuation of recognition accuracy will gradually decrease with increases in the number of features. In the process of particle size classification, if the training model has a single particle size range, the recognition accuracy of each particle size range is low, with the highest recognition accuracy being 98% and the average recognition rate being only 97.2%. The method proposed in this paper can effectively improve the recognition accuracy of each particle size range. The maximum recognition accuracy is 100%, the maximum increase is 4%, and the average recognition accuracy is 99.2%. Therefore, this method has a high practical application value for the separation of coal and gangue with single particle size.

PL

W celu zbadania wpływu zmian wielkości cząstek węgla i skały płonnej na dokładność rozpoznawania oraz poprawienia dokładności identyfikacji pojedynczych cząstek węgla i skały płonnej przez urządzenia sortujące, w ramach tej pracy utworzono bazę danych różnych rozmiarów cząstek węgla i skały płonnej za pomocą obrazów szarych i ekstrakcję cech tekstury przy użyciu algorytmu wyboru cech reliefowych w celu porównania różnych rozmiarów cząstek węgla i skały płonnej przy optymalnych cechach kombinacji oraz identyfikacji punktów i wielkości cząstek węgla i skały płonnej. Wyniki pokazują, że optymalne liczby cech węgla i skały płonnej są różne dla różnych rozmiarów cząstek. W oparciu o technologię separacji węgla i skały płonnej w świetle widzialnym, zmiana wielkości cząstek węgla i skały płonnej powoduje fluktuacje dokładności rozpoznawania, a te z kolei będą stopniowo zmniejszać się wraz ze wzrostem liczby cech. W procesie klasyfikacji wielkości cząstek, jeśli model uczący ma jeden zakres wielkości cząstek, dokładność rozpoznawania każdego zakresu wielkości cząstek jest niska, przy czym najwyższa dokładność rozpoznawania wynosi 98%, a średni wskaźnik rozpoznawania wynosi tylko 97,2%. Metoda zaproponowana w tym artykule może skutecznie poprawić dokładność rozpoznawania każdego zakresu wielkości cząstek. Maksymalna dokładność rozpoznawania wynosi 100%, maksymalny wzrost to 4%, a średnia dokładność rozpoznawania to 99,2%. Dlatego ta metoda ma dużą praktyczną wartość użytkową do oddzielania węgla i skały płonnej według rozmiaru pojedynczej cząstki.

5

Emission-intensity-enhanced GaN-based LED based on multilayer grating structures

Li Xin, Sun Dejie, Han Kun, Cao Lijun, Guo Shiliang, Li Zhiquan

Optica Applicata

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2021

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Vol. 51, nr 4

529--540

EN

A novel surface-plasmon-enhanced GaN-LED is proposed to improve the emission efficiency of the traditional LED. The SiO2 film, Ag triangular structure and ITO film were coated on the rectangularly-patterned p-GaN layer sequentially, which can form the quasi-symmetrical waveguide structure to enhance the internal quantum efficiency and the light extraction efficiency. The COMSOL software is used to simulate the LED structure. The radiated powers, absorbed powers and distribution of electric field are obtained and analyzed. The results reveal that emission efficiency of the proposed GaN-LED can be greatly improved.

6

Analysis of the main body behaviour of non-point source pollution control based on multimodal game model

Li Xin, Shang Jie

Ecological Chemistry and Engineering. S

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2021

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Vol. 28, nr 4

563--579

EN

The issue of agricultural non-point source pollution has attracted the attention of the state and the masse. In the non-point source pollution control organizations which composed of the governments, farmers and fertiliser sellers, due to the characteristics of rational economic body, the phenomenon of ”market failure” and ”government failure” may occur in the process of non-point source pollution control. In this paper, the author applies game theory to analyse the main behaviour characteristics of the three main bodies, and constructs the incomplete information dynamic game model that the government, farmers and fertiliser sellers participate in. According to the results of the equilibrium solution of the Haysani Axiom model, it is found that the decisions made by the three bodies of the government, the fertiliser seller and the farmer in the behaviour choice stage have a great influence on the behaviour choice of the other two bodies, and the process of each strategy choice by the three bodies is a dynamic game process of the three bodies. Finally, according to the main influencing factors reflected in the equilibrium solution, proposed the related non-point source pollution control countermeasure suggestion to the government main body.

7

Green Fabrication of Nanoscale Energetic Molecular Perovskite (H2dabco)[Na(ClO4)3] with Reduced Mechanical Sensitivity

Hu Li-shuang, Du Zelin, Liu Yang, Gong Shida, Guang Chunyu, Li Xin, Yang Zhi, Jia Qi, Liang Kaili

Central European Journal of Energetic Materials

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2021

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Vol. 18, no. 3

369--384

EN

High-energy-density molecular perovskite energetic materials with high detonation performance have attracted much attention, but poor safety performance has limited their potential applications. In this paper, nano sodium perchlorate-based molecular perovskite (H2dabco)[Na(ClO4)3] (nano DAP-1) was fabricated by green ball-milling technology. The structure and morphology of the samples were characterized and the results showed that nano DAP-1 with nearly spherical morphology has a narrow particle size distribution, < 1 μm. The thermal decomposition properties were investigated by differential scanning calorimetry (DSC). The exothermic peak of nano DAP-1 thermal decomposition was 330.0 °C, a decrease of 51.7 °C compared with that of raw DAP (381.7 °C). The apparent activation energy (Ea) of nano DAP-1 was calculated to be 160.9 kJ·mol–1, which is lower than that of raw DAP-1 (168.6 kJ·mol–1). Mechanical sensitivity studies showed that nano DAP-1 (H50: 64 cm) exhibited a lower impact sensitivity than that of the raw DAP-1 (H50: 51 cm). This work provides a simple and effective way for improving the thermal decomposition properties and safety performance of molecular perovskite energetic materials.

8

Reliability study on non-contact traction power supplysystem based on fuzzy grey relational FTA

Pei Yanxia, Li Xin

Archives of Electrical Engineering

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2021

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Vol. 70, nr 2

253--270

EN

The traction power supply system based on Inductively Coupled Power Transfer (ICPT) technology is one of the new traction power supply technologies that will bedeveloped in the future. As the core part of rail transit energy transfer and conversion, thetraction power supply system is not only the critical system for the safe operation of railtransit, but also the main source of its failures, so it is of great significance to study itsreliability. In this paper, the reliability analysis of the non-contact traction power supplysystem based on mobile ICPT technology is carried out using the method of (Fault Tree Analysis) FTA combined with triangular fuzzy theory and grey relational theory. Firstly,the fault tree of the system is established, and the minimum cut sets and structure functionof the fault tree are obtained. Then the triangular fuzzy numbers are introduced to representthe probability of the bottom events, and the fuzzy probability of the top event and the fuzzyimportance of the bottom events are determined, after that, the maximum probability offailure of the top event is obtained. Finally, the grey relational degrees of each minimum cutset are obtained and ranked. Furthermore, in order to prove the correctness of this method,the trapezoidal fuzzy FTA is introduced and compared with it. Both research results showthat the loosely coupled transformer and Insulated Gate Bipolar Transistor (IGBT) moduleare the weak links of the system. The results obtained are consistent and realistic, whichproves the correctness of the method selected in this article.

9

Transmission characteristics of the mobile inductively coupled power transfer system for dual transmitters and pickups based on PSpice

Gao Xin, Li Xin

Archives of Electrical Engineering

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2020

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Vol. 69, nr 1

147--157

EN

In order to meet the application requirements of high-power mobile inductivelycoupled power transfer (ICPT) equipment, the structure of the dual transmitter and pickup can be used to improve the transmission power of the ICPT system. However, this structure cannot easily describe the change of the mutual inductance parameter in the moving state, making the mathematical model difficult to establish. The change of load parameters during the movement will affect the current and voltage at the transmitter and pickup coils. Aiming at these problems, this paper proposes a dual transmitter and pickup ICPT system based on inductor-capacitor-inductor (LCL) compensation network, and analyzes its power transmission efficiency. By setting the shape and size of the coil, the influence of the change of the mutual inductance parameters on the system efficiency during the movement is reduced. The changes of the mutual inductance parameters of the ICPT system under the moving state are simulated by changing the coupling coefficient in the PSpice software. The results show that the structure of the ICPT system used in this paper can improve the output power and reduce the influence of the system when the load changes.

10

Preparation and properties of Ba2+–Y3+ co-doped γ-Ce2S3 red pigment

Li Xin, Li Yueming, Li Zhike, Wang Zhumei, Hong Yan, Song Fusheng

Materiały Ceramiczne

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2019

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T. 71, nr 4

378--388

EN

In this study, Ba2+-Y3+ co-doped γ-Ce2S3 (abbreviated as γ-[Ba,Y]-Ce2S3) red pigments were synthesized by a co-precipitation method according to the composition of n(Ba)/n(Ce1-xYx) = 0.1 (molar ratio, x = 0, 0.01, 0.03, 0.05, and 0.10 mol). The corresponding vulcanized products, γ-[Ba,Y]-Ce2S3 red pigment (SYx), were prepared at 850 °C for 150 min by using CS2 as a sulphur source. The effect of the Y3+ doping content on the phase composition, chromaticity, and thermal stability of Ba2+-Y3+ co-doped γ-Ce2S3 was systematically investigated by FE-SEM, EDS, XRD, Raman spectroscopy, HR-TEM, XPS, CIELAB colorimeter, and TG-DTA. The results show that a pure γ phase can be obtained for SYx at 850 °C, when x is varied from 0 to 0.05 mol. Whereas new heterogeneous phases, i.e., α-Ce2S3 and BaY2S4, were observed when the Y3+ content was larger than 0.05. As the Y3+ content increased, the band gap of γ-[Ba,Y]-Ce2S3 increased from 2.12 eV to 2.15 eV, which led to a colour change from red to red-orange. The chromaticity value of the pigments was raised from L* = 31.84, a* = 30.95, b* = 23.63 (S.Y0.00) to L* = 36.69, a* = 41.83, b* = 41.00 (S.Y0.01), indicating that the Ba2+-Y3+ co-doping can effectively increase the chromaticity value. The S.Y0.01 sample still presented a pure γ-phase after heat treatment at 440 °C for 10 min in air, which indicated that the Ba2+-Y3+ co-doping successfully increased the thermal stability of the γ-[Ba,Y]-Ce2S3 red pigment.

PL

W niniejszych badaniach, czerwone pigmenty Ba2+-Y3+ γ-Ce2S3 (w skrócie γ-[Ba,Y]-Ce2S3) zostały zsyntetyzowane metodą współstracania zgodnie ze składem n(Ba)/n(Ce1-xYx) = 0,1 (stosunek molowy, x = 0, 0,01, 0,03, 0,05 i 0,10 mol). Odpowiednie produkty wulkanizowane, czerwony pigment γ-[Ba,Y]-Ce2S3 (SYx), wytworzono w 850 °C przez 150 min, stosując CS2 jako źródło siarki. Wpływ zawartości domieszki Y3+ na skład fazowy, chromatyczność i stabilność termiczną γ-Ce2S3 współdomieszkowanego Ba2+-Y3+ był systematycznie badany za pomocą FE-SEM, EDS, XRD, spektroskopii Ramana, kolorymetru HR-TEM, XPS, CIELAB i TG-DTA. Wyniki pokazują, że dla SYx można uzyskać w 850 °C czystą fazę γ, gdy x zmienia się od 0 do 0,05 mola. Podczas gdy nowe heterogeniczne fazy, tj. α-Ce2S3 i BaY2S4, zaobserwowano, gdy zawartość Y3+ była większa niż 0,05. Wraz ze wzrostem zawartości Y3+ pasmo wzbronione γ-[Ba, Y]-Ce2S3 wzrosło z 2,12 eVdo 2,15 eV, co doprowadziło do zmiany koloru z czerwonego na czerwono-pomarańczowy. Wartość chromatyczności pigmentów podniesiono z L* = 31,84, a* = 30,95, b* = 23,63 (S.Y0,00) do L* = 36,69, a* = 41,83, b* = 41,00 (S.Y0.01), wskazując, że współdomieszkowanie Ba2+-Y3+ może skutecznie zwiększyć wartość chromatyczności. Próbka S.Y0.01 nadal wykazywała czystą fazę γ po obróbce cieplnej w 440 °C przez 10 min w powietrzu, co wskazywało, że jednoczesne domieszkowanie Ba2+-Y3+ skutecznie zwiększyło stabilność termiczną czerwonego pigmentu γ-[Ba,Y ]-Ce2S3.