13 results on '"Lu, Ran"'
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2. A simple method to construct multivariate dual framelets with high-order vanishing moments.
- Author
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Lu, Ran
- Abstract
When constructing multivariate framelets, it is often unavoidable to work with matrices of multivariate trigonometric polynomials and complicated matrix decomposition problems. These problems become even harder when good properties such as high-order vanishing moments are required on the framelets. In this paper, we establish a new method for constructing multivariate dual framelets with high-order vanishing moments. The underlying scheme of our algorithm is the famous Mixed Extension Principle that allows us to derive the high-pass filters (or framelet generators) from a given pair of refinable filters with high-order linear-phase moments. Our method only involves two steps: (1) directly constructing the first few pairs of high-pass filters by using the linear-phase moment conditions of the refinement filters; (2) solving a system of linear equations to obtain the rest of the high-pass filters. Both are easy to implement for scientific computation, regardless of what dimension or dilation matrix we work with. Apart from high-order vanishing moments, we will see that if the refinement filters take coefficients from some subfield 픽 of ℂ that is closed under complex conjugation, so do the high-pass filters. Furthermore, our algorithm gives the upper bounds for the number of high-pass filters in arbitrary dimensions. At the end of the paper, we will give several illustrative examples, from which we can also see that the support sizes of the high-pass filters are comparable with those of the refinement filters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Is it harmful to me or to us? A dyadic analysis of Chinese young adults' dysfunctional individuation and romantic relationship satisfaction.
- Author
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Zhang, Lu Ran and Chen, Wei‐Wen
- Subjects
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INDIVIDUATION (Psychology) , *SATISFACTION , *YOUNG adults - Abstract
This study aimed at examining how romantically involved Chinese young adults' dysfunctional individuation was associated with their and their partners' perceptions of romantic relationship satisfaction. We recruited 296 Chinese couples who were currently in heterosexual romantic relationships at the university. The couples completed self‐report measures of their dysfunctional individuation and relationship satisfaction. Results from the cross‐sectional actor–partner interdependence model (APIM) indicated that (a) for both genders, actor effects existed: Chinese young adults' dysfunctional individuation was negatively associated with their romantic relationship satisfaction; (b) in terms of partners' effects, women's dysfunctional individuation was negatively associated with men's perceptions of relationship satisfaction; but (c) men's dysfunctional individuation was not significantly associated with women's perceptions of relationship satisfaction. The findings were the first to reveal the actor and partner effects of dysfunctional individuation on romantic relationship satisfaction. The study results provided practical implications regarding how young adults can have satisfying romantic relationships. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. A refined full-spectrum temperature-induced subsurface thermal expansion model and its contribution to the vertical displacement of global GNSS reference stations.
- Author
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Li, Zhao, Lu, Ran, Jiang, Weiping, Dong, Danan, Lei, Jintao, Lu, Yang, Ding, Xin, Yang, Kaichun, Chen, Hua, and Chen, Qusen
- Abstract
The thermal expansion effects of GNSS stations are influenced by not only temperature variations, but also bedrock depths and types. Unfortunately, the current studies treat the subsurface GNSS monument and their nearby bedrock as a whole, without taking into account the inconsistencies among bedrock depths and types, while the existing full-spectrum finite element method (FEM) cannot be easily extended to consider the bedrock information. To solve this problem, we propose a refined full-spectrum temperature-induced subsurface thermal expansion model (FSHBDT) that considers both seasonal and non-seasonal temperature variations as well as bedrock information based on the half-space harmonic model. Results show that the full-spectrum half-space harmonic model (FSH), which considers only seasonal and non-seasonal temperature variations, can obtain comparable results to the FEM and even outperform the FEM for inland stations. In addition, the depth and type of bedrock have significant effects on the annual amplitude and phase of thermal expansion-induced vertical displacement. In particular, we find that the station displacement increases by more than 1 mm and the annual phase delays by up to 10° for high-latitude and deeper bedrock stations when bedrock depths are taken into account. The FSHBDT improves the correlation coefficient between GNSS height and mass load displacements by up to 42.3% compared to the FEM and explains up to 8.2% of the nonlinear variation in the GNSS height time series. Our work confirms the advantage of rigorous subsurface thermal expansion modeling to correct the nonlinear variations of global GNSS stations, which might provide a potential opportunity to improve the terrestrial reference frame toward the goal of 1 mm accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Generalized Matrix Spectral Factorization with Symmetry and Construction of Quasi-Tight Framelets over Algebraic Number Fields.
- Author
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Lu, Ran
- Subjects
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ALGEBRAIC numbers , *ALGEBRAIC fields , *MATRIX decomposition , *SYMMETRY , *ARITHMETIC , *SYMMETRIC matrices , *RATIONAL numbers - Abstract
The rational field Q is highly desired in many applications. Algorithms using the rational number field Q algebraic number fields use only integer arithmetics and are easy to implement. Therefore, studying and designing systems and expansions with coefficients in Q or algebraic number fields is particularly interesting. This paper discusses constructing quasi-tight framelets with symmetry over an algebraic field. Compared to tight framelets, quasi-tight framelets have very similar structures but much more flexibility in construction. Several recent papers have explored the structure of quasi-tight framelets. The construction of symmetric quasi-tight framelets directly applies the generalized spectral factorization of 2 × 2 matrices of Laurent polynomials with specific symmetry structures. We adequately formulate the latter problem and establish the necessary and sufficient conditions for such a factorization over a general subfield F of C , including algebraic number fields as particular cases. Our proofs of the main results are constructive and thus serve as a guideline for construction. We provide several examples to demonstrate our main results. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. 3D printing of a SiO2@BN TPMS structure: Efficient heat transfer strategy for BN/epoxy composites.
- Author
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Lu, Ran, Zhang, Yikun, Shen, Minhao, Yu, Shixiang, Zhu, Yu, Xu, Yue, Liu, Houbao, and Fu, Renli
- Subjects
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HEAT transfer , *THREE-dimensional printing , *MICROELECTRONIC packaging , *HEAT conduction , *THERMAL conductivity , *EPOXY resins - Abstract
The high integration density of microelectronic devices leads to local heat accumulation, and effective heat dissipation and signal transmission of packaging materials have become the primary issues to be solved. However, existing polymer materials have difficulty meeting the requirements due to their unsatisfactory thermal conductivity and thermal expansion properties. In this work, we proposed the use of digital light processing (DLP) printing technology to construct a triply periodic minimum surface (TPMS) skeleton, and a continuous and efficient heat conduction path was successfully constructed in epoxy resin by impregnating h-BN on the skeleton surface. When the loading of h-BN was 20 vol%, the thermal conductivity of the TPMS(SiO 2)@BN/EP(BN) composites was 1.86 W/(m·K), which was 786 % higher than that of pure epoxy resin. In addition, the thermal expansion coefficient of the composites decreased by more than 70 %. At the test frequencies of 3∼10 MHz, the composites showed stable dielectric properties, and the dielectric constant was always maintained in a low range, between 3.85 and 4.15. This work has realized the transformation of the method for constructing a heat conduction path from disordered to ordered and from random to repeatable. This provides a new strategy for the selection of microelectronic packaging materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
7. Multicolour LED lighting achieved by an array phosphor-converted film and blue-LED chip.
- Author
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Cheng, Zheng, Lu, Ran, Meng, Meng, Liu, Xiangjie, Qian, Fengjiao, and Fu, Renli
- Subjects
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LIGHT emitting diodes , *LED lighting , *CONVERTING (Packaging) , *OUTDOOR living spaces , *LIGHT sources , *DAYLIGHT , *PHOSPHORS - Abstract
A multicolour LED is a miniaturized, long-lasting, and easy-to-achieve colour adjustable emission light source. It is widely used in outdoor displays and room lighting fields. However, the increase in the cost and the decrease in luminous efficiency when adjusting lighting colours have constrained the development of multicolour LEDs. In this study, we initially designed a phosphor conversion pixel array through optical simulation and then prepared the phosphor conversion pixel arrays with different layouts using a semi-cured template method. Finally, we packaged the phosphor conversion pixel array with the blue LED array as a remote phosphor LED. The measurement of the luminous performance indicated that the colour gamut of multicolour LEDs was included in the simulated colour gamut, and the colour of the light was consistent with the design guidelines. Notably, the multicolour LED emission efficiency packaged with a phosphor conversion pixel array could reach 125 lm/W, and the hexagonal phosphor conversion pixel array had better emission performance than the square phosphor conversion pixel array. • Based on the Monte Carlo principle, multicolour LEDs composed of array phosphor-converted film and blue-LED chip are designed. • Phosphor-converted pixel arrays are prepared by semi-cured template method with high moulding quality. • By comparing the experimental and simulation results, colour-tuneable characteristics of the multicolour LEDs is verified. • The luminous efficiency of multicolour LEDs reach up to 125.0 lm/W and changing pixel can reduce the secondary reabsorption of fluorescence. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Production of fructo-oligosaccharide syrup through catalysis of <italic>Bacillus amyloliquefaciens</italic> levanase and immobilized Ba-SacB on cell lysate.
- Author
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Gao, Song, Qi, Xianghui, Lu, Ran, Zhu, Song, Kan, Guoshi, Stanishneva-Konovalova, Tatiana, An, Yingfeng, and Lu, Fuping
- Abstract
Levan is a type of fructan with β-(2, 6) fructosyl linkage. In recent years, levan has been used in the medicinal, food and chemical industries for its excellent physicochemical properties of good thermal stability, low viscosity, pseudoplasticity, and non-swelling in water. The levansucrase is key enzyme responsible for biosynthesis of levan from substrate sucrose. In the present study cell lysate of
Escherichia coli was used as support for convenient immobilization of Ba-SacB (i.e., Ba-SacB-Cell-Lysate) under the action of dopamine. Compared with the free Ba-SacB, the Ba-SacB-Cell-Lysate showed surprisingly enhanced pH stability in the pH range 6–9, and improved relative activities in the pH ranges 4–5 and 7–10. With the presence of 10% (v/v) butyl alcohol, 5mmol/L Fe3+, and after vortex for 90 min, the Ba-SacB-Cell-Lysate showed up to 14.32 times, 4.63 times, and 9.2 times higher relative activities than the free Ba-SacB. The Ba-SacB-Cell-Lysate kept nearly 81% of the residual activity after 9 cycles of reuse. The fructo-oligosaccharide syrup (FOS) was efficiently produced through the catalysis of levanase with the substrate of levan produced by Ba-SacB-Cell-Lysate, and the preparation conditions were optimized by Box-Behnken response surface methodology. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
9. Cu metallization of Al2O3 ceramics via CuO reduction: Role of SiO2 additive and sintering atmosphere.
- Author
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Hu, Yunjia, Shen, Minhao, Liu, yunan, Xu, Xinya, Lu, ran, and Cheng, Rui
- Subjects
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COPPER , *BRAZING alloys , *ALUMINUM oxide , *EUTECTICS , *SINTERING , *COPPER powder , *MELTING points - Abstract
A Cu-coated Al 2 O 3 substrates which can be used for power modules are prepared via sintering and reduction of CuO–SiO 2 film onto the surface of Al 2 O 3 ceramic without precious metal brazing filler or high-vacuum equipment. This method has a significant cost advantage over the existing technology. Effects of oxygen partial pressure from sintering atmosphere and SiO 2 content on microstructure and mechanical properties of Cu/Al 2 O 3 interface are systematically investigated. Phase compositions and morphologies of sintered Cu 2 O layer, reduced Cu layer and reactive layer are characterized via X-ray diffraction and scanning electron microscopy. In addition, physicochemical changes within CuO–SiO 2 during sintering are characterized by thermogravimetry-differential scanning calorimeter. It is found that oxygen and SiO 2 can promote the generation of Cu 2 O–CuO–SiO 2 eutectic phase with low melting point upon sintering, which increases the thickness of reaction layer and the densification of Cu layer. The shear strength between the Cu layer and the Al 2 O 3 substrate is enhanced with the increase in Cu layer densification degree, while varying in irregular manner with the thickness of reaction layer. In particular, the highest shear strength of 62.70 MPa is obtained at oxygen partial pressure of 0.02 atm and SiO 2 content of 1.5 wt%. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
10. In vitro and in vivo study of antibacterial and anti‐encrustation coating on ureteric stents.
- Author
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Zhao, Yue, Chen, Guo, Yushanjiang, Suliya, Zhao, Meng, Yang, Hui, Lu, Ran, Qu, Rui, Dai, Yi, and Yang, Luo
- Subjects
- *
URINARY tract infections , *SURFACE coatings , *IN vivo studies , *SEISMIC testing , *IN vitro studies - Abstract
Objectives: To investigate the ability of propolis‐coated ureteric stents to solve complications, especially urinary tract infections (UTIs) and crusting, in patients with long‐term indwelling ureteric stents through antimicrobial and anti‐calculus activities. Materials and Methods: Polyurethane (PU) ureteric stents were immersed in the ethanol extract of propolis (EEP), a well‐known antimicrobial honeybee product, and subjected to chemical, hydrophilic, and seismic tests. The antimicrobial activity of the EEP coating was then examined by in vitro investigation. Proteus mirabilis infection was induced in rats within uncoated and EEP‐coated groups, and the infection, stone formation, and inflammation were monitored at various time points. Results: The characterisation results showed that the hydrophilicity and stability of the EEP surface improved. In vitro tests revealed that the EEP coating was biocompatible, could eliminate >90% of bacteria biofilms attached to the stent and could maintain bacteriostatic properties for up to 3 months. The in vivo experiment revealed that the EEP‐coating significantly reduced the amount of bacteria, stones, and salt deposits on the surface of the ureteric stents and decreased inflammation in the host tissue. Conclusions: Compared with clinically used PU stents, EEP‐coated ureteric stents could better mitigate infections and prevent encrustation. Thus, this study demonstrated that propolis is a promising natural dressing material for ureteric stents. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
11. Strategies to Diversification of the Mechanical Properties of Organic Crystals.
- Author
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Dai, Shuting, Zhong, Jiangbin, Yang, Xiqiao, Chen, Chao, Zhou, Liping, Liu, Xinyu, Sun, Jingbo, Ye, Kaiqi, Zhang, Hongyu, Li, Liang, Naumov, Panče, and Lu, Ran
- Subjects
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CRYSTALS , *SHAPE memory polymers , *CHEMICAL engineering , *INTERMOLECULAR interactions , *MOLECULAR crystals , *CHEMICAL engineers - Abstract
Structurally ordered soft materials that respond to complementary stimuli are susceptible to control over their spatial and temporal morphostructural configurations by intersectional or combined effects such as gating, feedback, shape‐memory, or programming. In the absence of general and robust design and prediction strategies for their mechanical properties, at present, combined chemical and crystal engineering approaches could provide useful guidelines to identify effectors that determine both the magnitude and time of their response. Here, we capitalize on the purported ability of soft intermolecular interactions to instigate mechanical compliance by using halogenation to elicit both mechanical and photochemical activity of organic crystals. Starting from (E)‐1,4‐diphenylbut‐2‐ene‐1,4‐dione, whose crystals are brittle and photoinert, we use double and quadruple halogenation to introduce halogen‐bonded planes that become interfaces for molecular gliding, rendering the material mechanically and photochemically plastic. Fluorination diversifies the mechanical effects further, and crystals of the tetrafluoro derivative are not only elastic but also motile, displaying the rare photosalient effect. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
12. Strategies to Diversification of the Mechanical Properties of Organic Crystals.
- Author
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Dai, Shuting, Zhong, Jiangbin, Yang, Xiqiao, Chen, Chao, Zhou, Liping, Liu, Xinyu, Sun, Jingbo, Ye, Kaiqi, Zhang, Hongyu, Li, Liang, Naumov, Panče, and Lu, Ran
- Subjects
- *
CRYSTALS , *SHAPE memory polymers , *CHEMICAL engineering , *INTERMOLECULAR interactions , *MOLECULAR crystals , *CHEMICAL engineers - Abstract
Structurally ordered soft materials that respond to complementary stimuli are susceptible to control over their spatial and temporal morphostructural configurations by intersectional or combined effects such as gating, feedback, shape‐memory, or programming. In the absence of general and robust design and prediction strategies for their mechanical properties, at present, combined chemical and crystal engineering approaches could provide useful guidelines to identify effectors that determine both the magnitude and time of their response. Here, we capitalize on the purported ability of soft intermolecular interactions to instigate mechanical compliance by using halogenation to elicit both mechanical and photochemical activity of organic crystals. Starting from (E)‐1,4‐diphenylbut‐2‐ene‐1,4‐dione, whose crystals are brittle and photoinert, we use double and quadruple halogenation to introduce halogen‐bonded planes that become interfaces for molecular gliding, rendering the material mechanically and photochemically plastic. Fluorination diversifies the mechanical effects further, and crystals of the tetrafluoro derivative are not only elastic but also motile, displaying the rare photosalient effect. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
13. A sequence recommendation method based on external reinforcement and position separation.
- Author
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Wu, Wenya, Wang, Guangjin, Liang, Xiufang, Zhu, Yingzheng, Duan, Huajuan, Liu, Peiyu, and Lu, Ran
- Abstract
Sequential Recommendation systems play a crucial role in predicting users’ preferences based on their behavioral history. However, the existing methods ignore the extrapolation nature of sequences and do not make deep use of item provider information. This oversight limits the model’s ability to fully utilize relevant external properties. To alleviate these limitations, we design a recommendation model that incorporates Position encoding and external reinforcement (Item -Provider), named DPSRec. Specifically, we design an Embed Encoding layer, in order to distinguish the Position Embedding of previous sequence models, we combine the time variability with the position encoding with extrapolation property, and encode the item and item provider sequences accordingly. Meanwhile, to avoid the noise that the initial item embeddings might cause with Position Encoding, we calculate the position Encoding separately from the item embedding. In addition, we design a Cross Propagation layer to capture implicit higher-order dependencies between item sequences. Extensive experiments on three real-world datasets demonstrate that the proposed model generally outperforms the baselines by about 1–12.5%. Our source code will be published after the paper is published. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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