作者机构：
[Xie, H. C.] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Peoples R China.;[Liao, D. H.] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Peoples R China.
通讯机构：
[D.H. Liao] C;College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, 410004, PR China
关键词：
Time-dependent reliability analysis;Interval variable;Two-level meta-models;Polynomial chaos expansion;Kriging model
摘要：
This paper proposes a new time-dependent reliability analysis method based on a two-level meta-models technique for problems with interval variables, through which the upper and lower bounds of reliability indexes of structures within a given design lifetime period can be obtained efficiently. Firstly, the time parameter, interval and stochastic process parameters in the performance function are transformed into the corresponding random variables. Secondly, the polynomial chaos expansion (PCE) approach is adopted for using an approximate polynomial expression to accurately surrogate the complex original performance function. Thirdly, the Kriging meta-model of time-dependent reliability index about the interval variables is constructed based on the approximate expression, and the upper and lower bounds of the reliability index are calculated with the efficient global optimization (EGO) method. Finally, the effectiveness of the proposed method is verified by investigating three numerical examples.
作者机构：
[Xie, Guodong; Si, Jiayong; Cai, Gemei] Coll Mech & Elect Engn, Cent South Univ Forestry & Technol, Changsha 410004, Hunan, Peoples R China.;[Si, Jiayong; Cai, Gemei; Li, Guihua] Sch Mat Sci & Engn, Cent South Univ, Changsha 410083, Hunan, Peoples R China.
通讯机构：
[Jiayong Si] C;[Gemei Cai] S;School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083, China<&wdkj&>College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China
摘要：
Investigating the phosphors doped with single activators in a single component to realize white-light emission is urgently desired for phosphor-converted white-light-emitting diodes. In this work, on the basis of the chemical unit cosubstitution strategy, the new borophosphate phosphors Ba(3)CaK(PO(4))(3-x)(BO(3))(x):0.02Eu(2+) with a mixed anion group were prepared. Coupling structure refinement and photoluminescence analyses, Ba(3)CaK(PO(4))(3-x)(BO(3))(x) consists of five different cationic sites with different coordination environments, with Eu(2+) occupying the three sites for Ba(2+). In the process of partial substituting (BO(3))(3-) for (PO(4))(3-), because of the greatly distorted coordination field generated from the difference in the geometric configurations between the two anion groups, a red shift and broadening of the emission bands occurs, resulting in a color-adjustable emission from blue to white. A phosphor-converted light-emitting diode has been successfully fabricated with the incorporation of an as-prepared Ba(3)CaK(PO(4))(2.6)(BO(3))(0.4):0.02Eu(2+) phosphor and a 405 nm near-ultraviolet chip, which exhibits Commission International de I'Eclairage chromaticity coordinates of (0.31, 0.37) and a correlated color temperature of 6295 K. As demonstrated in the present work, an approach adopted from phosphate to borophosphate is conducted to develop high-quality phosphors.
期刊：
Journal of Alloys and Compounds,2022年927:167045 ISSN：0925-8388
通讯作者：
Jiayong Si<&wdkj&>Gemei Cai
作者机构：
[Si, Jiayong; Zhang, Jing] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410004, Hunan, Peoples R China.;[Cai, Gemei; Huang, Junben; Li, Guihua] Cent South Univ, Sch Mat Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Zhou, Tianliang] Xiamen Univ, Coll Mat, Xiamen 361005, Fujian, Peoples R China.
通讯机构：
[Jiayong Si] C;[Gemei Cai] S;School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083, China<&wdkj&>College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China
摘要：
Exploring for red-emitting phosphor materials with supper property plays a key role in the development of white light-emitting diodes (WLEDs). Simultaneously, the crystal structure has a crucial effect on its lu-minescence properties. In this work, we synthesized a type of new red-emitting Li4Ca2B8O16: Eu3+ phosphor via the solid-state reaction. The phase purity, crystal structure, surface morphology, decay behavior, thermal stability, the correspondence between local symmetry and luminescence properties were investigated in detail. Under the optimal 393 nm excitation, Li4Ca2B8O16: 0.33Eu3+ shows a strong red emission located at 612 nm ascribed to the 5D0 -> 7F2 transition of Eu3+. The calculated Judd-Ofelt parameters (& UOmega;2 and & UOmega;4) have clarified that Eu3+ has lower symmetry without an inversion center, resulting in the high value of R/O (the emission intensity ratio of 5D0 & RARR;7F2 to 5D0 & RARR;7F1) of 7.95 at x = 0.33 mol. The Li4Ca2B8O16: 0.33Eu3+ phosphor exhibits a high color purity of 94.99% with the chromaticity coordinates of (0.6547, 0.3449), perfect internal quantum efficiency (99.75%) and excellent thermal stability at high temperature (90.91% at 150 ?). The results indicate that this new Li4Ca2B8O16: Eu3+ phosphor can be used as the potential red component for pc-WLEDs.(c) 2022 Elsevier B.V. All rights reserved.
期刊：
Chemical Engineering Journal,2022年428:130985 ISSN：1385-8947
通讯作者：
Ma, Xiancheng;Li, Liqing
作者机构：
[Fang, Muaoer; Wu, Qingding; Ma, Xiancheng] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410083, Hunan, Peoples R China.;[Chen, Ruofei; Li, Liqing; Zeng, Zheng; Shi, Rui; Liu, Baogen] Cent South Univ, Sch Energy Sci & Engn, Changsha 410083, Hunan, Peoples R China.
通讯机构：
[Ma, Xiancheng; Li, Liqing] C;Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410083, Hunan, Peoples R China.;Cent South Univ, Sch Energy Sci & Engn, Changsha 410083, Hunan, Peoples R China.
关键词：
Biomass;Light hydrocarbons adsorption and separation;Porous carbon;Porous structure
摘要：
The light hydrocarbons adsorption and separation from mixed gas is very important to the petroleum industry. Herein, a simple and effective strategy for preparing hierarchical porous carbons (HPCs) derived from biomass and urea with tunable pore size distribution is proposed. With the increase of urea content, the pore size distributions of HPCs become narrow, and the surface area (from 3588 to 2626 m(2) g(-1)) and total pore volume (2.605 to 1.688 mL g(-1)) decrease. Tested at an adsorption temperature of 25 degrees C and a pressure of 1 bar, the resulting HPC800-0.5 has excellent C3H8 (12.18 mmol g(-1)) and C2H6 (6.88 mmol g(-1)) uptake capacity, while HPC800-1.5 exhibits the highest IAST-predicted C3H8/CH4 (91) and C2H6/CH4 (15) selectivity. Molecular simulations suggest that the porous structure (or more specifically micropores) has a more prominent effect on C2H6 and C3H8 capture at 1 bar than functional groups. The selectivity of C3H8/CH4 and C2H6/CH4 mainly depends on the narrow micropores (C3H8/CH4, pore size <1.2 nm and C2H6/CH4, pore size <1 nm) of carbon-based materials. This study provides insights for the further design and development of adsorbents for light hydrocarbons adsorption and separation from natural gas.
摘要：
The uncertainties quantification of fiber path parameters is essential for fully developing the variable stiffness composite laminates (VSCL) performance. How to design a reliable fiber placing scheme effectively with a given mechanical requirement is an important issue to be considered. To achieve a feasible solution, a data-driven-based approximate Bayesian computation (ABC) inverse method is suggested. The novelty of this paper lies in three aspects. We employ the auto-encoder to extract the feature vector of the high-dimensional physical field as the form of a summary statistical quantity of the ABC. Back propagation neural network is applied to construct the mapping between the fiber path parameters and the feature vectors to avoid the time-consuming physical field simulation. Finally, a hybrid adaptive nested sampling strategy is proposed by introducing the differential operation to accelerate the sampling process of posterior distribution of fiber path parameters. Two VSCL engineering examples are used to verify the feasibility of the suggested method. The experiment results indicate that the available fiber path parameters with uncertainties can be obtained based on the suggested inverse identification framework.
作者机构：
[Dong, Xinran] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, 498 South Shaoshan St, Changsha 410004, Peoples R China.;[Zeng, Li; Sun, Xiaoyan; Duan, Ji'an] Cent South Univ, Coll Mech & Elect Engn, State Key Lab High Performance Complex Mfg, 932 South Lushan St, Changsha 410083, Peoples R China.;[Chu, Dongkai] Shandong Univ, Ctr Adv Jet Engn Technol CaJET, Sch Mech Engn, 17923 Jingshi Rd, Jinan 250061, Shandong, Peoples R China.
通讯机构：
State Key Laboratory of High Performance Complex Manufacturing, College of Mechanical and Electrical Engineering, Central South University, 932 South Lushan Street, Changsha, China
关键词：
Overexposed FBGs;Femtosecond laser;Temperature stability;Annealing;Rapid air cooling treatment
期刊：
Separation and Purification Technology,2022年303:122237 ISSN：1383-5866
通讯作者：
Xiancheng Ma<&wdkj&>Qingding Wu<&wdkj&>Liqing Li
作者机构：
[Wu, Yi; Wu, Qingding; Ma, Xiancheng] Cent South Univ Forestry & Technol, Coll Mech & Elect Engn, Changsha 410083, Hunan, Peoples R China.;[Li, Liqing; Zeng, Zheng; Guo, Yang] Cent South Univ, Sch Energy Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Su, Rongkui] Cent South Univ Forestry & Technol, Coll Environm Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Yao, Xiaolong] Beijing Technol & Business Univ, Dept Environm Sci & Engn, 11 Fuchenglu, Beijing 100048, Peoples R China.;[Wang, Shaobin] Univ Adelaide, Sch Chem Engn & Adv Mat, 108 King William St, Adelaide, SA 5005, Australia.
通讯机构：
[Xiancheng Ma; Qingding Wu] C;[Liqing Li] S;College of Mechanical & Electrical Engineering, Central South University of Forestry and Technology, Changsha 410083, Hunan, China<&wdkj&>School of Energy Science and Engineering, Central South University, Changsha 410083, Hunan, China
关键词：
Porous carbon;Pore structure;Nitrogen and oxygen groups;Iodine capture
摘要：
The removal of radioactive iodine species during nuclear accidents and nuclear fuel reprocessing is crucial to nuclear safety, public health and environmental protection. Here, a series of nitrogen-doped porous carbon derived from benzimidazole (NBCs) with well-developed pore structure were prepared. During KOH activation, the potassium salt formed at 600-700 degrees C is mainly K2CO3 and K2O, and the pore size obtained is mainly microporous. With the temperature increases, the K2CO3 and K2O are converted to KOCN, which generates mesopores. NBCs were subsequently tested for gaseous iodine and solution iodine. The results show that NBC800-2 exhibits the highest iodine vapor adsorption capacity (7873 mg/g) at 75 celcius. Theoretical calculations and experimental data show that the iodine adsorption of NBCs for iodine vapor is mainly determined by pore structure, especially micropores and narrow mesoporous. The effect of nitrogen and oxygen doping on the adsorption capacity of gaseous iodine is limited. In the cyclohexane solution, the adsorption capacity of NBCs for iodine is mainly determined by micropores. In KI/H2O solution, the iodine adsorption mainly depends on mi-cropores and narrow mesopores, which is completely different from the result of iodine adsorption in cyclo-hexane. This is mainly due to the fact that I3- has a larger diameter than I2, and the adsorption energy of I3- (82.8 kJ/mol) on the carbon surface is higher than that of I2 (58.1 kJ /mol). Moreover, Langmuir model can better describe the adsorption process of iodine in cyclohexane and KI/H2O solution than Freundlich model, which proves that the process is mainly monolayer formation. This study provides insights for the further design and development of adsorbents for iodine capture from nuclear waste and nuclear accidents.
