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

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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

Enhancing photoresponsiveness of metal-organic polyhedra by modifying microenvironment

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Nano Research 2024年第6期17卷 5712-5717页

作者： Long Zheng peng Tan Qian Song Sheng-Tao Wang Min Li Xiao-Qin Liu Lin-Bing sun State Key Laboratory of Materials-Oriented Chemical Engineering Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)College of Chemical EngineeringNanjing Tech UniversityNanjing 211816China

Photoresponsiveness of materials is critical to their tunability and efficiency in terminal *** metal-organic polyhedra(PMOPs)feature intrinsic pores and remote controllability,but aggregation of PMOPs in solid state hampers their photoresponsiveness ***,we report the construction of a new PMOP(Cu_(24)(C_(16)H_(12)N_(2)O_(4))_(12)(C_(18)H_(22)O_(5))12,denoted as MOP-PR-LA),where long alkyl(LA)chains act as the intermolecular poles,propping against adjacent PMOP molecules to create individual microenvironment benefiting the isomerization of photoresponsive(PR)*** ultraviolet(UV)-and visible-light irradiation,MOP-PR-LA is much easier to isomerize than the counterpart MOP-PR without *** propylene adsorption,MOP-PR has a low change of adsorption capacity(9.9%),while that of MOP-PR-LA reaches 58.6%.Density functional theory calculations revealed that PR in the cis state has a negative effect on adsorption,while the trans state of PR favors *** work might open an avenue for the construction of photoresponsive materials with high responsiveness and controllability.

关键词： photoresponsive adsorption metal-organic polyhedra azobenzene long alkyl chains propylene capture

Fault Diagnosis for Railway Point Machines Using VMD Multi-scale Permutation Entropy and ReliefF Based on Vibration Signals

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Chinese Journal of Electronics 2024年

作者： Yongkui sun Yuan CAO peng LI Shuai SU National Engineering Research Center of Rail Transportation Operation and Control System Beijing Jiaotong University School of Automation and Intelligence Beijing Jiaotong University Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong University

The railway point machine plays an important part in railway systems. It is closely related to the safe operation of trains. Considering the advantages of vibration signals on anti-interference, this paper develops a novel vibration signal-based diagnosis approach for railway point machines. First, variational mode decomposition(VMD)is adopted for data preprocessing, which is verified more effective than empirical mode decomposition. Next, multiscale permutation entropy is extracted to characterize the fault features from multiple scales. Then ReliefF is utilized for feature selection, which can greatly decrease the feature dimension and improve the diagnosis accuracy. By experiment comparisons, the proposed approach performs best on diagnosis for railway point machines. The diagnosis accuracies on reverse-normal and normal-reverse processes are respectively 100% and 98.29%.

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Can soil organic carbon sequestration and the carbon management index be improved by changing the film mulching methods in the semiarid region?

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Journal of Integrative Agriculture 2024年第5期23卷 1541-1556页

作者： Jialin Yang Liangqi Ren Nanhai Zhang Enke Liu Shikun sun Xiaolong Ren Zhikuan Jia Ting Wei peng Zhang College of Agronomy Northwest A&F UniversityYangling 712100China Key Laboratory of Crop Physi-Ecology and Tillage Science in Northwestern Loess Plateau Ministry of Agriculture and Rural AfairsNorthwest A&FUniversityYangling 712100China Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100081China College of Water Resources and Architectural Engineering Northwest A&F UniversityYangling 712100China

Plastic film mulching has been widely used to increase maize yield in the semiarid area of ***, whether long-term plastic film mulching is conducive to agricultural sustainability in this region remains controversial.A field experiment was initiated in 2013 with five different film mulching methods:(i) control method, flat planting without mulching (CK),(ii) flat planting with half film mulching (P),(iii) film mulching on ridges and planting in narrow furrows(S),(iv) full film mulching on double ridges (D), and (v) film mulching on ridges and planting in wide furrows (R).The effects on soil organic carbon (SOC) content, storage, and fractions, and on the carbon management index (CMI)were evaluated after nine consecutive years of plastic film *** results showed that long-term plastic film mulching generally maintained the initial SOC *** with no mulching, plastic film mulching increased the average crop yield, biomass yield, and root biomass by 48.38, 35.06, and 37.32%, respectively, which led to the improvement of SOC ***, plastic film mulching significantly improved CMI, and increased the SOC content by 13.59%, SOC storage by 7.47%and easily oxidizable organic carbon (EOC) by 13.78%on average,but it reduced the other labile *** sequestration and CMI were improved by refining the plastic film mulching *** S treatment had the best effect among the four mulching methods, so it can be used as a reasonable film mulching method for sustainable agricultural development in the semiarid area.

关键词： plastic film mulching soil organic carbon labile organic carbon fractions semiarid area

AHFO-based soil water content sensing technology considering soile sensor thermal contact resistance

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2715-2731页

作者： Mengya sun peng Wu Bin Shi Jin Liu Jie Liu Juncheng Yao Yipin Lu Yunqiang Wang Xiaoyan Li School of Earth Sciences and Engineering Hohai UniversityNanjing210098China School of Earth Sciences and Engineering Nanjing UniversityNanjing210023China Department of Architecture and Civil Engineering City University of Hong Kong999077Hong KongChina State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an710061China

The actively heated fiber-optic(AHFO)technology has become emerged as a research focus due to its advantages of distributed,real-time measurement and good *** attributes have led to the gradual application of AHFO technology to the water content measurement of in situ ***,all existing in situ applications of AHFO technology fail to consider the effect of soilesensor contact quality on water content measurements,limiting potential for the wider application of AHFO *** address this issue,the authors propose a method for determining the soilesensor thermal contact resistance based on the principle of an infinite cylindrical heat *** is then used to establish an AHFO water content measurement technology that considers the thermal contact *** reliability and validity of the new measurement technology are explored through a laboratory test and a field case study,and the spatial-temporal evolution of the soil water content in the case is *** results demonstrate that method for determining the soilesensor thermal contact resistance is highly effective and applicable to all types of *** method requires only the moisture content,dry density,and thermal response of the in situ soil to be *** the field case,the measurement error of soil water content between the AHFO method,which takes into account the thermal contact resistance,and the neutron scattering method is only *** water content of in situ soil exhibits a seasonal variation,with an increase in spring and autumn and a decrease in summer and ***,the response of shallow soils to precipitation and evaporation is *** findings contribute to the enhancement of the accuracy of the AHFO technology in the measurement of the water content of in situ soils,thereby facilitating the dissemination and utilization of this technology.

关键词： Soil water content Actively heated fiber-optic(AHFO) technology Soilesensor thermal contact resistance Reliability In situ application

Construction of core@double-shell structured energetic composites with simultaneously enhanced thermal stability and safety performance

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Defence Technology（防务技术） 2024年第4期34卷 134-142页

作者： peng Wang Wen Qian Ruolei Zhong Fangfang He Xin Li Jie Chen Li Meng Yinshuang sun Guansong He Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China State Key Laboratory of Environment-friendly Energy Materials School of Materials and ChemistrySouthwest University of Science and TechnologyMianyang 621010China

The poor thermal stability and high sensitivity severely hinder the practical application of hexanitrohexaazaisowurtzitane(CL-20).Herein,a kind of novel core@double-shell CL-20 based energetic composites were fabricated to address the above *** coordination complexes which consist of natural polyphenol tannic acid(TA) and Fe~Ⅲ were chosen to construct the inner shell,while the graphene sheets were used to build the outer *** resulting CL-20/TA-Fe~Ⅲ/graphene composites exhibited simultaneously improved thermal stability and safety performance with only 1 wt% double-shell content,which should be ascribed to the intense physical encapsulation effect from inner shell combined with the desensitization effect of carbon nano-materials from outer *** phase transition(ε to γ) temperature increased from 173.70 ℃ of pure CL-20 to 191.87℃ of CL-20/TA-Fe~Ⅲ/graphene ***,the characteristic drop height(H_(50)) dramatically increased from 14.7 cm of pure CL-20 to112.8 cm of CL-20/TA-Fe~Ⅲ/graphene composites,indicating much superior safety performance after the construction of the double-shell *** general,this work has provided an effective and versatile strategy to conquer the thermal stability and safety issues of CL-20 and contributes to the future application of high energy density energetic materials.

关键词： CL-20 Double-shell structure Thermal stability Safety performance Tannic acid Graphene sheets

Identifying the effective combination of acupuncture and traditional Chinese medicinal herbs for postmenopausal osteoporosis therapy through studies of their molecular regulation of bone homeostasis

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Journal of Traditional Chinese Medicine 2024年第1期44卷 212-219页

作者： REN Ping WANG Quanwu BAI Wei sun Miao LIU Zheling GAO Ming WANG Liang peng Bo XU Liguang Department of Health Management the Third Affiliated Clinical Hospital of Changchun University of Chinese MedicineChangchun 130117China Department of Dirty Tuina the affiliated Hospital to Changchun University of Chinese MedicineChangchun 130117China Department of Acupuncture the affiliated Hospital to Changchun University of Chinese MedicineChangchun 130117China Department of Rehabilitation Medicine the 924th Hospital of the PLA Joint Logistic Support ForceFoshan 528226China Department of College of Acupuncture and Massage Changchun University of Chinese MedicineChangchun 130117China

Worldwide,as the population age,osteoporosis is becoming increasingly common,and osteoporotic fractures have a significant economic *** women are the most susceptible to developing osteoporosis and the most critical time to prevent it is during the perimenopausal and early menopausal *** this regard,we hypothesize rational combination of acupuncture and Traditional Chinese Medicine(TCM)in the form of herbal extract could prevent osteoporosis in *** deficiency during menopause causes low-level inflammation that stimulates the formation of osteoclasts,the boneresorbing cells,and simultaneously inhibits the viability and function of osteoblasts,the bone-forming *** most potent inflammatory cytokine in skeletal homeostasis is the receptor activator of nuclear factor kappa B ligand(RANKL)that stimulates osteoclast ***,the canonical Wnt pathway is essential for osteoblastogenesis and bone formation,and estrogen deficiency leads to diminished functioning of this *** and acupuncture could target the RANKL and the Wnt pathway in favorable ways to prevent the accelerated bone loss experienced during the early menopausal stage and promote the gain in bone mass in postmenopausal *** this review,we propose a rational combination of specific TCM and acupuncture targeting those signaling molecules/pathways by the drugs that are in clinical use for the treatment of postmenopausal *** rational approach revealed that Danshen(Radix Salviae Miltiorrhizae)could exert a synergistic effect with *** then propose a translational path for developing the putative combination in women with postmenopausal osteoporosis to curtail the risk of osteoporotic fractures.

关键词： medicine traditional osteogenic anti-resorptive review

Composite structure Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG ceramics with high color spatial uniformity for white laser lighting

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Journal of Advanced Ceramics 2024年第2期13卷 189-197页

作者： pengfei Sang Le Zhang Jian Kang Mingzhou Li Shiwei Chen peng Yang Bingheng sun Yang Li Wieslaw Strek Hao Chen Jiangsu Key Laboratory of Advanced Laser Materials and Devices School of Physics and Electronics EngineeringJiangsu Normal UniversityXuzhou 221116China Jiangsu Xiyi Advanced Materials Research Institute of Industrial Technology Xuzhou 221400China Xuzhou EAGLED Technology Co. Ltd.Xuzhou 221116China Xuzhou Kangna Advanced Materials Technology Co. Ltd.Xuzhou 221116China Xuzhou Fuchang Electronic Technology Co. Ltd.Xuzhou 221116China Shanghai Institute of Optics Fine Mechanics Chinese Academy of SciencesShanghai 201800China School of Material Science and Engineering Shanghai Institute of TechnologyShanghai 201418China State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China Institute of Low Temperature and Structure Research Polish Academy of SciencesWroclaw 50-422Poland

Composite ceramic phosphor(CCP)is a candidate light-conversion material to obtain the high-quality laser lighting *** based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal *** this study,a novel composite structure ceramic was designed,including Al_(2)O_(3)-YAG:Ce/YAG layered ceramic with a size of 1 mm×1 mm for lighting,and Al_(2)O_(3) ceramic(φ=16.0 mm)was used as the wrapping material due to its outstanding thermal *** prepared ceramics exhibited excellent thermal performance and no yellow ring *** this design,we achieved the match of the intensity distribution of the blue and yellow lights,resulting in a high angular color uniformity of 0.9 with a view angle of±80°.All ceramics showed no luminous saturation phenomenon,even the laser power density was increased up to 47.51 W/mm^(2).A high-brightness white-light source with a luminous flux of 618 lm,a luminous efficiency of 126 lm/W,a CCT of 6615 K,and a CRI of 69.9 was obtained in the transmissive *** particular,the surface temperature of the ceramic was as low as 74.1℃ under a high laser radiation(47.51 W/mm^(2)).These results indicate that Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.

关键词： Al_(2)O_(3)/Al_(2)O_(3)-YAG:Ce/YAG angular color uniformity high thermal stability high-power laser lighting

Boosting oxygen reduction in acidic media through integration of Pt-Co alloy effect and strong interaction with carbon defects

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Nano Research 2024年第9期17卷 7900-7908页

作者： Nannan Ji Haoyun Sheng Shilong Liu Yangyuan Zhang Hongfei sun Lingzhi Wei Ziqi Tian peng Jiang Qianwang Chen Jianwei Su Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid MaterialsAnhui UniversityHefei 230601China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China Hefei National Laboratory for Physical Science at Microscale Department of Materials Science&EngineeringUniversity of Science and Technology of ChinaHefei 230026China International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China

Optimization of Pt atom utilization efficiency is critical for the development of proton-exchange-membrane fuel *** we aim to develop an efficient oxygen reduction reaction(ORR)catalyst with a low Pt content through the concurrent modification of Pt-Co alloy catalysts and carbon *** the present study,ultrafine Pt-Co alloy nanoparticles are successfully synthesized and stabilized by topological carbon defects via adopting the ammonia thermal *** the low Pt loading,the obtained catalyst exhibits an impressive half-wave potential of 0.926 V versus the reversible hydrogen electrode in 0.1 M HClO_(4)***,the durability testing using the timed-current method demonstrates a tiny loss of only 3.6%after 12 *** experimental results and theoretical calculations demonstrate that topological carbon defects significantly enhance the charge transfer processes at the alloy/carbon interface,contributing to the strong electronic metal-support interactions between the Pt-Co alloy nanoparticles and topological carbon *** interactions,along with the alloy effect,play a crucial role in promoting the ORR performance in acidic media.

关键词： electrocatalysis oxygen reduction reaction Pt-Co alloy electronic interaction topological carbon defects