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Impact of Annealing on the Melt Recrystallization of a-PDLA/α-PLLA Double-layered Films

Chinese Journal of Polymer Science 2024年第2期42卷 230-238,I0009页

作者： Yun-Peng Li hao-ran shen Shao-Juan Wang hao Zhang Jian Hu Rui Xin Xiao-Li Sun Shou-Ke Yan Key Laboratory of Rubber-Plastics Ministry of Education/Shandong Provincial Key Laboratory of Rubber-plasticsQingdao University of Science&TechnologyQingdao266042China State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing100029China

Poly(lactic acid)(PLA) as a bio-based polymer with biodegradability and biocompatibility has attracted much attention. To manipulate its properties for different applications, regulation of crystal structure and crystalline morphology becomes an attractive research topic. In this work, the structure evolution of layered samples containing an amorphous poly(D-lactide)(PDLA) layer and a crystalline poly(L-lactide)(PLLA)layer with highly oriented edge-on α lamellar crystals after annealing at 150 ℃ or/and after melt-recrystallization has been studied by AFM, FTIR,and TEM combined with electron diffraction. The results demonstrate that melt recrystallization of the as-prepared sample leads to the formation of abundant randomly oriented PLA stereo-complex(PLA SC) crystals. Annealing at 150 ℃ results in the formation of a small amount of oriented PLA SC crystals at the interface. These PLA SC crystals show great impact on the recrystallization behavior of sample after melting at 190 ℃ and then crystallizing at 90 ℃. First, they impede the mutual diffusion of the overlying PDLA and underlying PLLA, and thus reduce their stereocomplexation ability as manifested by the decreased amount of PLA SC crystals. Second, they act as substrate to initiate the epitaxial crystallization of the overlying PDLA and underlying PLLA, which ensures the production of a highly oriented structure of PDLA and PLLA after melt recrystallization again.

关键词： Poly(L-lactide) Poly(D-lactide) Double layer Stereocomplex

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A chiral aldehyde-induced tandem conjugated addition–lactamization reaction for constructing fully substituted pyroglutamic acids

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Organic Chemistry Frontiers 2022年第5期9卷 1422-1426页

作者： Wen-Zhe Wang hao-ran shen Jian Liao Wei Wen Qi-Xiang Guo Key Laboratory of Applied Chemistry of Chongqing Municipality School of Chemistry and Chemical EngineeringSouthwest UniversityChongqing400715China

A catalytic asymmetric tandem reaction including a chiral aldehyde catalyzed conjugated addition and an intramolecular lactamization is reported in this *** the optimal reaction conditions,various fully substituted pyroglutamic acids bearing three vicinal chiral centers were generated in good-to-excellent yields and stereoselectivities.A reasonable reaction mechanism is proposed to illustrate the observed stereoselective control results.

关键词： chiral substituted conjugated

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Uncertainty and sensitivity analysis of in-vessel phenomena under severe accident mitigation strategy based on ISAA-SAUP program

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Nuclear Science and Techniques 2024年第1期35卷 108-123页

作者： hao Yang Ji-shen Li Zhi-ran Zhang Bin Zhang Jian-Qiang Shan School of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

The phenomenology involved in severe accidents in nuclear reactors is highly ***,integrated analysis programs used for severe accident analysis heavily rely on custom empirical parameters,which introduce considerable ***,in recent years,the field of severe accidents has shifted its focus toward applying uncertainty analysis methods to quantify uncertainty in safety assessment programs,known as“best estimate plus uncertainty(BEPU).”This approach aids in enhancing our comprehension of these programs and their further development and *** study concentrates on a third-generation pressurized water reactor equipped with advanced active and passive mitigation *** an Integrated Severe Accident Analysis Program(ISAA),numerical modeling and uncertainty analysis were conducted on severe accidents resulting from large break loss of coolant *** uncertainty parameters of the ISAA program were meticulously *** Wilks'formula,the developed uncertainty program code,SAUP,was employed to carry out Latin hypercube sampling,while ISAA was employed to execute batch *** analysis was then conducted on two figures of merit,namely hydrogen generation and the release of fission products within the pressure *** calculations revealed that hydrogen production and the fraction of fission product released exhibited a normal distribution,ranging from 182.784 to 330.664 kg and from 15.6 to 84.3%,*** ratio of hydrogen production to reactor thermal power fell within the range of 0.0578–0.105.A sensitivity analysis was performed for uncertain input parameters,revealing significant correlations between the failure temperature of the cladding oxide layer,maximum melt flow rate,size of the particulate debris,and porosity of the debris with both hydrogen generation and the release of fission products.

关键词： Gen-III PWR Severe accident mitigation Wilks’formula Hydrogen Fission products Uncertainty and sensitivity analysis

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Structure and Representations for Electrical Lie Algebra of Type D_(5)

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Algebra Colloquium 2024年第2期31卷 271-284页

作者： Yulu Chen ran shen Yucai Su College of Science Donghua UniversityShanghai 201620China 不详

In this paper,we prove that the electrical Lie algebra e D_(5)is isomorphic to the semidirect product of sp_(4)and a 2-step nilpotent Lie ***,we classify the irreducible highest weight modules for e D_(5).

关键词： electrical Lie algebra 2-step nilpotent Lie algebra highest weight module

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H_(∞)/Passive Synchronization of Semi-Markov Jump Neural Networks Subject to Hybrid Attacks via an Activation Function Division Approach

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Journal of Systems Science & Complexity 2024年第3期37卷 1023-1036页

作者： ZHANG Ziwei shen hao SU Lei School of Electrical and Information Engineering Anhui University of TechnologyMa'anshan 243002China Anhui Province Key Laboratory of Special Heavy Load Robot and School of Electrical and Information Engineering Anhui University of TechnologyMa'anshan243002China

In this work,an H_(∞)/passive-based secure synchronization control problem is investigated for continuous-time semi-Markov neural networks subject to hybrid attacks,in which hybrid attacks are the combinations of denial-of-service attacks and deception attacks,and they are described by two groups of independent Bernoulli *** this foundation,via the Lyapunov stability theory and linear matrix inequality technology,the H_(∞)/passive-based performance criteria for semi-Markov jump neural networks are ***,an activation function division approach for neural networks is adopted to further reduce the conservatism of the ***,a simulation example is provided to verify the validity and feasibility of the proposed method.

关键词： Activation function division approach deception attacks denial-of-service attacks H_(∞)/passive synchronization semi-Markov jump neural networks

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Artificial hawk-eye camera for foveated, tetrachromatic, and dynamic vision

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Journal of Semiconductors 2024年第9期45卷 1-3页

作者： Wenhao ran Zhuoran Wang Guozhen shen School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100081China Institute of Flexible Electronics Beijing Institute of TechnologyBeijing 102488China

With the rapid development of drones and autonomous vehicles, miniaturized and lightweight vision sensors that can track targets are of great interests. Limited by the flat structure, conventional image sensors apply a large number of lenses to achieve corresponding functions, increasing the overall volume and weight of the system.

关键词： awk vision system.

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Large reversible magnetocaloric effect in antiferromagnetic Er_(3)Si_(2)C_(2) compound

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Journal of Rare Earths 2024年第8期42卷 1555-1559,I0005页

作者： hao Sun Lu Tian Xinqiang Gao Zhaojun Mo Jun shen Baogen shen School of Rare Earths University of Science and Technology of ChinaHefei230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou34100China Department of Energy and Power Engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing00081China

The magnetic properties,magnetic phase transition and magnetocaloric effects(MCE) of Er_(3)Si_(2)C_(2) compound were investigated based on theoretical calculations and experimental *** on the first principles calculations,the antiferromagnetic(AFM) ground state type in Er_(3)Si_(2)C_(2) compound was predicted and its electronic structure was *** experimental results show that Ei_(3)Si_(2)C_(2) compound is an AFM compound with the Neel temperature(I_N) of 7 K and undergoes a field-induced firstorder magnetic phase transition from AFM to ferromagnetic(FM) under magnetic fields exceeding 0.6 T at 2 *** magnetic transition process of Er_(3)Si_(2)C_(2) compound was investigated and *** values of the maximum magnetic entropy change(-ΔS_(M)^(max)) and the refrigeration capacity(RC) are 17 J/(kg·K)and 193 J/kg under changing magnetic fields of 0-5 T,*** a potential cryogenic magnetic refrigerant,the Er_(3)Si_(2)C_(2) compound also provides an interesting research medium to study the magnetic phase transition process.

关键词： Magnetic materials Magnetocaloric Metamagnetic transitions Magnetic phase transition Rare earths

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Highly efficient photocatalytic conversion of CO_(2) into CH_(4) over Cu single atom promoted heterojunction:The effect of uplifted d-band center

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Chinese Chemical Letters 2024年第2期35卷 484-488页

作者： hao Zhang Qian Liu Zhurui shen School of Materials Science and Engineering Nankai UniversityTianjin 300350China

Photoreduction of CO_(2) to solar fuels has caused great interest,but suffers from low catalytic efficiency and poor ***,we designed a S-scheme heterojunction(Cu-TiO_(2)/WO_(3))with Cu single atom to significantly boost the photoreduction of CO_(2).Notably,the developed Cu-TiO_(2)/WO_(3) achieved the solardriven conversion of CO_(2) to CH_(4) with an evolution rate of 98.69μmol g^(−1) h^(−1),and the electron selectivity of CH_(4) reached 88.5%.The yield was much higher than those of pristine WO_(3),TiO_(2)/WO_(3) and Cu-TiO_(2) *** and theoretical analysis suggested that the S-scheme heterojunction accelerated charge migration and inhibited the recombination of electron-hole ***,the charge separation effect of the heterojunction meliorated the position of the *** uplifted d-band centers of Cu and Ti on Cu-TiO_(2)/WO_(3) not only improved the electron interaction between Cu single atoms and substrate-TiO_(2),accelerated the adsorption and activation of CO_(2) on the active sites of Cu single atom,but also optimized the Gibbs free energies of CH 4 formation pathway,leading to excellent selectivity toward CH_(4).This work provides new insights into the design of photocatalyst systems with high photocatalytic performance.

关键词： Cu single atom Heterojunction CO_(2)photoreduction d-band center DFT

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Real-time monitoring of oxygenation in deep brain tissue using a wireless photoelectric probe

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Science China Materials 2024年第4期67卷 1361-1362页

作者： hao Pang Qilin Hua Guozhen shen School of Integrated Circuits and Electronics Beijing Institute of TechnologyBeijing 100084China Institute of Flexible Electronics Beijing Institute of TechnologyBeijing 102488China

Oxygen(O2) supply to the brain is of utmost importance for human health, as cerebral hypoxia can result in irreversible brain damage. Neurodegenerative diseases, such as epilepsy, are closely associated with cerebral hypoxia [1,2]. Real-time monitoring of cerebral oxygenation holds significant value in neuroscience research and clinical diagnostics [3–10].

关键词： epilepsy cerebral diseases

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Decadal length-of-day and geomagnetic changes imply more complex Earth’s core motions

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Science Bulletin 2024年第13期69卷 2038-2041页

作者： hao Ding Jiancheng Li Weiping Jiang Wenbin shen School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan UniversityWuhan 430079China GNSS Research Center Wuhan UniversityWuhan 430079China

Since the 1950s,the length-of-day variations(DLOD)of the Earth’s rotation have received extensive attention and research in various fields,including geodynamics,geomagnetism,geodesy,seismology,geology,marine science,environmental science,and even biology and *** the abundance of related studies and notable advancements,the underlying mechanism behind the decadal changes in DLOD remains a persistent unresolved *** essential aspect of investigating this issue lies in its potential to unveil the Earth’s core motions[1,2].Despite the presence of various hypothesized and constructed models about the Earth’s core motions,these models typically exhibit simplicity.

关键词： Earth geology geomagnetic

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