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Synthesis of Bis(4'-hydroxyphenyl)-toluene-2, 4-diurethane for Main Chain Liquid Crystalline Poly(urethane-ester)s

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Chinese Chemical Letters 1998年第5期9卷 439-442页

作者： Yan qing LIAN Ming qi LI qi xiang zhou De Shan LIU(Institute of Polymer Science and Engineering, Department of Chemical Engineering,Tsinghua University, Beijing 100084) Tsing Hua Univ Dept Chem Engn Inst Polymer Sci & Engn Beijing 100084 Peoples R China

A new methodology was advanced that mesogenic cores appeared after theformation of urethane groups and during the monomer-to-polymer transition. A newdiphenol monomer, bis(4'-hydroxy-phenyl)-toluene-2 (BHPTU), was obtainedby the reaction of 2,4-tolulene diisocyanate with hydroquinone in dioxane or N,N-dimethyl-acetandde. The reaction process was monitored by FTIR, and the product was investigated bylH NMR and elemental analysis (EA). A liquid crystalline poly(urethane-ester) was obtainedusing the BHPTU monomer.

关键词： liquid crystalline polymer poly(urethane-ester) synthesis

Flexible polydimethylsiloxane pressure sensor with micro-pyramid structures and embedded silver nanowires:A novel application in urinary flow measurement

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Nanotechnology and Precision Engineering 2024年第3期7卷 1-12页

作者： Ben-Song Wang Ang Gao Song-Wei Huang qi-Hong Ning Cheng zhou qi-xiang Song Da-xiangCui School of Electronic Information and Electrical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Urology Renji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 200240China

Flexible pressure sensors are lightweight and highly sensitive,making them suitable for use in small portable devices to achieve precise measurements of tiny *** article introduces a low-cost and easy-fabrication strategy for piezoresistive flexible pressure *** embedding silver nanowires into a polydimethylsiloxane layer with micro-pyramids on its surface,a flexible pressure sensor is created that can detect low pressure (17.3 Pa) with fast response (<20 ms) and high sensitivity (69.6 mA kPa-1).Furthermore,the pressure sensor exhibits a sensitive and stable response to a small amount of water flowing on its *** this basis,the flexible pressure sensor is innovatively combined with a micro-rotor to fabricate a novel urinary flow-rate meter (uroflowmeter),and results from a simulated human urination experiment show that the uroflowmeter accurately captured all the essential shape characteristics that were present in the pump-simulated urination *** ahead,this research provides a new reference for using flexible pressure sensors in urinary flow-rate monitoring.

关键词： Flexible pressure sensor Silver nanowires Portable device Uroﬂowmeter Healthcare

Non-perturbative dynamics of flat-band systems with correlated disorder

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Chinese Physics B 2024年第9期33卷 547-551页

作者： qi Li Junfeng Liu Ke Liu Zi-xiang Hu zhou Li GBA Branch of Aerospace Information Research Institute Chinese Academy of SciencesGuangzhou 510535China Guangdong Provincial Key Laboratory of Terahertz Quantum Electromagnetics Guangzhou 510700China School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Department of Physics and Chongqing Key Laboratory for Strongly Coupled Physics Chongqing UniversityChongqing 401331China University of Chinese Academy of Sciences Beijing 100039China

We develop a numerical method for the time evolution of Gaussian wave packets on flat-band lattices in the presence of correlated *** achieve this,we introduce a method to generate random on-site energies with prescribed *** verify this method with a one-dimensional(1D)cross-stitch model,and find good agreement with analytical results obtained from the disorder-dressed evolution *** allows us to reproduce previous findings,that disorder can mobilize 1D flat-band states which would otherwise remain *** explained by the corresponding disorder-dressed evolution equations,such mobilization requires an asymmetric disorder-induced coupling to dispersive bands,a condition that is generically not fulfilled when the flat-band is resonant with the dispersive bands at a Dirac point-like *** exemplify this with the 1D Lieb *** analytical expressions are not available for the two-dimensional(2D)system due to its complexity,we extend the numerical method to the 2D a–T3 model,and find that the initial flat-band wave packet preserves its localization when a=0,regardless of disorder and ***,when a̸=0,the wave packet shifts in real *** interpret this as a Berry phase controlled,disorder-induced wave-packet *** addition,we present density functional theory calculations of candidate materials,specifically Hg1−*** flat-band emerges near the G point(α=0)in the Brillouin zone.

关键词： flat-band system dynamics correlated disorder

Analysis of flavor and widely metabolomics differences in black sesame before and after processing

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Oil Crop Science 2024年第1期9卷 38-45页

作者： Yini Yang Linhai Wang Yunhai Wang Yuting An qi zhou Xia xiang Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences Hubei Key Laboratory of Lipid Chemistry and NutritionKey Laboratory of Oil Seed Processing of Ministry of AgricultureOil Crops and Lipids Process Technology National and Local Joint Engineering LaboratoryWuhan430062China Natural Food International Holding Limited ShenzhenChina

The objective of this study was to determine the differences of aroma and taste in three black sesame originsbefore and after processing via flavor and widely *** analyzing the sensory characteristics and metabolites of raw and treated black sesame from China,Vietnam,and Myanmar,treated Chinese sesame have the most significant change in hardness after thermal processing,low viscosity and was easy to *** electronic nose could distinguish between raw and treated sesame due to the aroma *** reason of treated sesame from China was“fragrant”is due to the highest content(2545.50μg/kg)of total pyrazines including 2,5-dimethylpyrazine,2-ethyl-5-methylpyrazine,2,3,5-trimethylpyrazine,3-ethyl-2,5-dimethylpyrazine.933 metabolites were detected via a wide targeted metabolomics in the taste of raw and treated *** on the analysis of metabolites related to bitterness,145 substances were *** main bitter contributors may be amino acids,dipeptides and organic acids.

关键词： Flavoromics Metabolomics Black sesame Aroma Taste Distribution

Fracture sealing performance of granular lost circulation materials at elevated temperature:A theoretical and coupled CFD-DEM simulation study

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Petroleum Science 2024年第1期21卷 567-581页

作者： Chong Lin qi-Cong Xu Lie-xiang Han Gao Li Hai He Hong-Ling zhou Ji-Ping She CCDC Drilling&Production Technology Research Institute Guanghan618300SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina College of Materials Science and Engineering Chongqing UniversityChongqing400044China State Key Lab of Oil and Gas Reservoir Geology and Exploitation(Chengdu University of Technology) Chengdu610059SichuanChina College of Energy Chengdu University of TechnologyChengdu610059SichuanChina

Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)*** circulation material(LCM)is a regular preventive and remedial measure for lost ***,conventional LCMs seem ineffective in high-temperature *** may be due to the changes in the mechanical properties of LCMs and their sealing performance under high-temperature *** understand how high temperature affects the fracture sealing performance of LCMs,we developed a coupled computational fluid dynamics-discrete element method(CFD-DEM)model to simulate the behavior of granular LCMs in *** summarized the literature on the effects of high temperature on the mechanical properties of LCMs and the rheological properties of drilling *** conducted sensitivity analyses to investigate how changing LCM slurry properties affected the fracture sealing efficiency at increasing *** results show that high temperature reduces the size,strength,and friction coefficient of LCMs as well as the drilling fluid ***,softer,and less frictional LCM particles have lower bridging probability and slower bridging *** particles tend to form dual-particle bridges rather than single-particle *** result in a deeper,tighter,but unstable sealing *** drilling fluid viscosity leads to faster and shallower sealing zones.

关键词： Geothermal well drilling HTHP formationLost circulation material CFD-DEM Fracture sealing

Effect of the grain boundary character distribution on the sulfur corrosion behaviour and mechanisms of copper windings under different high temperatures

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High Voltage 2024年第3期9卷 566-580页

作者： Xu Dai Yuan Yuan Jiang zhou Guoyong Liu Tao Zhu Huiying xiang qi Yu Xue Gao Ruijin Liao State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina College of Materials Science and Engineering Chongqing UniversityChongqingChina Dongfang Electric Machinery Co. LtdDeyangChina

As a typical failure phenomenon in transformers,sulfur corrosion has garnered significant attention in the field of high-voltage *** boundary character distribution(GBCD)copper windings have been introduced to enhance sulfur corrosion resistance by slowing down intergranular *** this study,the sulfur corrosion behaviour and mechanisms of the GBCD copper windings under various temperatures were experi-mentally and theoretically *** show that GBCD can enhance the corrosion resistance of copper in liquid *** the increase in temperatures,the insulating properties of oil and papers in traditional copper windings experience notable degradation,while GBCD copper windings show more stable insulating *** addition,modelling of grain boundary energy indicates that the grain boundary structure of GBCD copper windings has a lower average interface energy of 0.170 eV/Å***-culations of reaction thermodynamics show that GBCD copper windings possess a higher failure temperature(135.2℃)and inhibition degree(activation energy)of the sulfur corrosion(32,557.62 J/mol),revealing the stability and enhanced sulfur corrosion resis-tance at elevated temperatures.

关键词： corrosion grain copper

Two Monte Carlo-based simulators for imaging-system modeling and projection simulation of flat-panel X-ray source

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Nuclear Science and Techniques 2024年第7期35卷 31-46页

作者： Meng-Ke qi Ting He Yi-Wen zhou Jing Kang Zeng-xiang Pan Song Kang Wang-Jiang Wu Jun Chen Ling-Hong zhou Yuan Xu School of Biomedical Engineering Southern Medical UniversityGuangzhou510515China State Key Laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou510275China Department of Radiotherapy Guangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhou510515China

The advantages of a flat-panel X-ray source(FPXS)make it a promising candidate for imaging *** imaging-system modeling and projection simulation are critical for analyzing imaging performance and resolving overlapping projection issues in *** conventional analytical ray-tracing approach is limited by the number of patterns and is not applicable to FPXS-projection ***,the computation time of Monte Carlo(MC)simulation is independent of the size of the patterned arrays in *** study proposes two high-efficiency MC projection simulators for FPXS:a graphics processing unit(GPU)-based phase-space sampling MC(gPSMC)simulator and GPU-based fluence sampling MC(gFSMC)*** two simulators comprise three components:imaging-system modeling,photon initialization,and physical-interaction simulations in the ***-system modeling was performed by modeling the FPXS,imaging geometry,and *** gPSMC simulator samples the initial photons from the phase space,whereas the gFSMC simulator performs photon initialization from the calculated energy spectrum and fluence *** entire process of photon interaction with the geometry and arrival at the detector was simulated in parallel using multiple GPU kernels,and projections based on the two simulators were *** accuracies of the two simulators were evaluated by comparing them with the conventional analytical ray-tracing approach and acquired projections,and the efficiencies were evaluated by comparing the computation *** results of simulated and realistic experiments illustrate the accuracy and efficiency of the proposed gPSMC and gFSMC simulators in the projection calculation of various phantoms.

关键词： Flat-panel X-ray source(FPXS) Imaging-system modeling Projection simulation Monte Carlo-based simulators

Experimental quantum state compression from two identical qubits to a qutrit

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 1-5页

作者： qiao Xu Lin-xiang zhou Tian-Feng Feng Shang-Feng qiu Si-Wu Li Wu-Ji Zhang Hui Luo Xiao-qi zhou State Key Laboratory of Optoelectronic Materials and Technologies and School of Physics Sun Yat-sen UniversityGuangzhou 510000China Hefei National Laboratory Hefei 230088China

In the realm of modern information technology,data compression technology occupies a pivotal *** advancements in quantum information technology,the need to compress large-scale qubits ensembles has become urgent,aiming to reduce the demand on quantum storage ***,existing quantum state compression schemes generally face a limitation:the particles before and after compression must reside in the same dimensional *** specific scenarios,compressing qubits into particles of higher dimensions not only enhances the efficiency of quantum state compression but also further reduces the usage of quantum storage *** we experimentally demonstrated a quantum state compression between particles of different dimensions,successfully compressing two qubits into a single *** average fidelity of the resulting qutrit with the ideal quantum state is *** study may have potential applications in future quantum information,such as increasing quantum communication bandwidth and reducing storage resource consumption in quantum computing.

关键词： quantum state compression quantum information technology optics

Factors and Their Impact on Treatment Effect of Acupuncture in Different Outcomes:A Meta-Regression of Acupuncture Randomized Controlled Trials

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Chinese Journal of Integrative Medicine 2024年第3期30卷 260-266页

作者： XIU Wen-cui GANG Wei-juan zhou qi SHI Lan-jun HU xiang-yu MING Tian-yu LUO Zhen ZHANG Yu-qing JING xiang-hong Institute of Acupuncture and Moxibustion China Academy of Chinese Medical SciencesBeijing100700China China Center for Evidence-Based Traditional Chinese Medicine China Academy of Chinese Medical SciencesBeijing100700China Department of Health Research Methods Evidenceand ImpactMcMaster UniversityHamiltonOntarioL8S 4L8Canada Center for Evidence-Based Integrative Medicine-Clarity Collaboration Guang’anmen HospitalChina Academy of Chinese Medical SciencesBeijing100053China

Background:The effects of acupuncture have varied in different randomized controlled trials(RCTs),and there are many factors that influence treatment effect of acupuncture in different outcomes,with conflicting ***:To identify factors and their impact on the treatment effect of acupuncture in different ***:Acupuncture RCTs were searched from 7 databases including Medline(Pub Med),Embase,Cochrane Central Register of Controlled Trials,China National Knowledge Infrastructure,Wanfang Database,VIP Database,and China Biology Medicine disc between January 1st,2015 and December 31st,*** studies must compare acupuncture to no acupuncture,sham acupuncture,or waiting lists,and report at least 1patient-important outcome.A multi-level meta-regression was conducted using a 3-level robust mixed model and univariate analyses were performed for all independent variables,even those excluded from the multivariable model due to *** used thresholds of 0.2 and 0.4 for the difference of standardized mean differences(SMDs),categorising them as small(0.4) ***:The pain construct analysis involved 211 effect estimates from 153 studies and 14 independent ***-frequency acupuncture treatment sessions produced larger effects compared to low-frequency sessions [large magnitude,the difference of adjusted SMDs 0.46,95% confidence interval(CI) 0.07 to 0.84;P=0.02].The non-pain symptoms construct analysis comprised 323 effect estimates from 231 studies and 15 independent *** acupuncture showed moderately larger effects when compared to non-penetrating acupuncture(0.30,95% CI 0.06 to 0.53;P=0.01).The function construct analysis included 495 effect estimates from 274 studies and 14 independent *** acupuncture and the flexible acupuncture regimen showed moderately larger effects,compared to non-penetrating acupuncture and fixed regimen,respectively(0.40,95% CI 0

关键词： acupuncture randomized controlled trial patient-important outcome meta-regression