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Gradient-structure-enhanced dielectric energy storage performance of flexible nanocomposites containing controlled preparation of defective TiO_(2) and ferroelectric KNbO_(3) nanosheets

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Nano Research 2024年第5期17卷 4079-4088页

作者： Yan Wang Lili zhao Ruicong Chen Wenhui zhao Dengwei Hu Haoran Wang Bin Cui Key Laboratory of Synthetic and Natural Functional molecule of the ministry of Education Shaanxi Key Laboratory of Physico–Inorganic Chemistry Xi’an Key Laboratory of Functional Supramolecular Structure and MaterialsCollege of Chemistry and Materials ScienceNorthwest UniversityXi’an 710127China School of Information Science and Technology Northwest UniversityXi’an 710127China Engineering Research Center for Titanium Based Functional materials and Devices in Universities of Shaanxi Province Faculty of Chemistry and Chemical EngineeringBaoji University of Arts and SciencesBaoji 721013China

Next generation power system needs dielectrics with increased dielectric energy ***,the low energy density of dielectrics limits their ***,an asymmetric trilayered nanocomposite,with a transition layer(TL),an insulation layer(IL),and a polarization layer(PL),is designed based on poly(vinylidene fluoride)-polymethyl methacrylate(PVDF-PmmA)matrix using KNbO_(3)(KN)and TiO_(2)(TO)as the *** morphology and defect control of the two-dimensional nano KN and nano TO fillers are realized via a hydrothermal method to increase the composite breakdown strength(E_(b))and the composite energy density(U_(e)).The asymmetric trilayered structure leads to a gradient electric field distribution,and the KN and TO nanosheets block charges transfer along z *** a result,the development path of the electrical trees is greatly curved,and E_(b) is effectively *** the Ue value of the nanocomposites reaches 17.79 J·cm^(-3) at 523 mV·m^(-1).On the basis,the composite Ue is further improved by defect control in TO *** nanocomposite KN/TO/PVDF-PmmA containing TO with less oxygen vacancy concentration(calcined at oxygen atmosphere)acquires a high Ue of 21.61 J·cm^(-3) at 548 mV·m^(-1).This study provides an idea for improving the energy storage performance by combining the design of the composite dielectric structure and the control of nanofillers’defect and morphology.

关键词： asymmetric trilayered structure two-dimensional energy density oxygen vacancies breakdown strength dielectric

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Dynamic RNA methylation modifications and their regulatory role in mammalian development and diseases

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Science China Life Sciences 2024年第10期67卷 2084-2104页

作者： Wenlan Yang Yongliang zhao Yungui Yang State Key Laboratory of Reproductive Regulation & Breeding of Grassland Livestock Inner Mongolia Key Laboratory for Molecular Regulation of the CellSchool of Life SciencesInner Mongolia University CAS Key Laboratory of Genomic and Precision medicine Beijing Institute of GenomicsChinese Academy of Sciences China National Center for Bioinformation School of Future Technology University of Chinese Academy of Sciences Sino-Danish College University of Chinese Academy of Sciences

Among over 170 different types of chemical modifications on RNA nucleobases identified so far, RNA methylation is the major type of epitranscriptomic modifications existing on almost all types of RNAs, and has been demonstrated to participate in the entire process of RNA metabolism, including transcription, pre-mRNA alternative splicing and maturation, mRNA nucleus export, mRNA degradation and stabilization, mRNA translation. Attributing to the development of high-throughput detection technologies and the identification of both dynamic regulators and recognition proteins, mechanisms of RNA methylation modification in regulating the normal development of the organism as well as various disease occurrence and developmental abnormalities upon RNA methylation dysregulation have become increasingly clear. Here, we particularly focus on three types of RNA methylations: N6-methylcytosine(m6A), 5-methylcytosine(m5C), and N7-methyladenosine(m7G). We summarize the elements related to their dynamic installment and removal,specific binding proteins, and the development of high-throughput detection technologies. Then, for a comprehensive understanding of their biological significance, we also overview the latest knowledge on the underlying mechanisms and key roles of these three mRNA methylation modifications in gametogenesis, embryonic development, immune system development, as well as disease and tumor progression.

关键词： RNA methylation (m6A m5C and m7G) detection techniques RNA metabolism gametogenesis embryogenesis immune system development tumorigenesis

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Design of digital calibration based on variable step size of sub-binary SAR ADC

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The Journal of China Universities of Posts and Telecommunications 2024年第2期31卷 62-71页

作者： Liu Wei zhao Yanke Shang Shiguang School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China

Addressing the impact of capacitor mismatch on the conversion accuracy of successive approximation register analog-to-digital converter(SAR ADC),a 12-bit 1 mS/s sub-binary SAR ADC designed using variable step size digital calibration was *** least mean square(LmS)calibration algorithm was employed with a ramp signal used as the calibration *** errors,extracted under injected disturbances,underwent iterative training to optimize weight *** address the trade-off between conversion accuracy and speed caused by a fixed step size,a novel variable step size algorithm tailored for SAR ADC calibration was *** core circuit and layout of the SAR ADC were implemented using the Taiwan Semiconductor manufacturing Company(TSmC)0.35μm complementary metal-oxide-semiconductor(CmOS)commercial *** of the SAR ADC calibration algorithm was conducted using Simulink,demonstrating quick convergence and meeting conversion accuracy requirements compared to fixed step size *** results indicated that the convergence speed of the LmS digital calibration algorithm with variable step size was approximately eight times faster than that with a fixed step size,also yielding a lower mean square error(mSE).After calibration,the simulation results for the SAR ADC exhibited an effective number of bit(ENOB)of 11.79 bit and a signal-to-noise and distortion ratio(SNDR)of 72.72 dB,signifying a notable enhancement in the SAR ADC performance.

关键词： successive approximation register analog-to-digital converter(SAR ADC) variable step size digital calibration disturbance technique

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Qualitative analysis of aromatic compounds via 1D TOCSY techniques

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magnetic Resonance Letters 2024年第1期4卷 21-27页

作者： Wenbo Dong Qi zhao Jiancheng zhao Jiarong Zhang Yingxiong Wang Yan Qiao State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of Sciences27 South Taoyuan RoadTaiyuan030001China Graduate University of Chinese Academy of Sciences Beijing100049China marine Biomedical Research Institution Guangdong Medical UniversityZhanjiang524023China College of Chemistry Taiyuan University of Technology79 Yingze West StreetWanbailin DistrictTaiyuan030024China

The aromatic compounds,including o-xylene,m-xylene,p-xylene,and ethylbenzene,primarily originate from the catalytic reforming of crude oil,and have a wide variety of ap***,because of similar physical and chemical properties,these compounds are difficult to be identified by gas chromatography(GC)without standard *** the development of modern nuclear magnetic resonance(NmR)techniques,NmR has emerged as a powerful and efficient tool for the rapid analysis of complex and crude mixtures without *** this study,the parameters of one-dimensional(1D)total correlation spectroscopy(TOCSY)NmR techniques,including 1D selective gradient TOCSY and 1D chemicalshift-selective filtration(CSSF)with TOCSY,were optimized to obtain comprehensive molecular structure *** results indicate that the overlapped signals in NmR spectra of nonpolar aromatic compounds(including o-xylene,m-xylene,p-xylene and ethylbenzene),polar aromatic compounds(benzyl alcohol,benzaldehyde,benzoic acid),and aromatic compounds with additional conjugated bonds(styrene)can be resolved in 1D *** importantly,full molecular structures can be clearly distinguished by setting appropriate mixing time in 1D *** approach simplifies the NmR spectra,provides structural information of entire molecules,and can be applied for the analysis of other structural isomers.

关键词： 1D TOCSY NmR technologies Xylenes Aromatic compounds Structure information of entire molecular Qualitative analysis

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Threshold Selection and Resource Allocation for Quantized Identification

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Journal of Systems Science & Complexity 2024年第1期37卷 204-229页

作者： WANG Ying LI Xin zhao Yanlong ZHANG Ji-Feng Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper is concerned with the optimal threshold selection and resource allocation problems of quantized identification, whose aims are improving identification efficiency under limited resources. Firstly, the first-order asymptotically optimal quantized identification theory is extended to the weak persistent excitation condition. Secondly, the characteristics of time and space complexities are established based on the Cramér-Rao lower bound of quantized systems. On these basis, the optimal selection methods of fixed thresholds and adaptive thresholds are established under aperiodic signals, which answer how to achieve the best efficiency of quantized identification under the same time and space complexity. In addition, based on the principle of maximizing the identification efficiency under a given resource, the optimal resource allocation methods of quantized identification are given for the cases of fixed thresholds and adaptive thresholds, respectively, which show how to balance time and space complexity to realize the best identification efficiency of quantized identification.

关键词： Quantized output resource allocation system identification threshold selection.

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Enhanced direct gaseous CO_(2) fixation into higher bio-succinic acid production and selectivity

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Journal of Environmental Sciences 2024年第9期143卷 164-175页

作者： Ziyi Yang Wanling Wu Qing zhao Irini Angelidaki Samuel Gyebi Arhin Dongliang Hua Yuxiao zhao Hangyu Sun Guangqing Liu Wen Wang Biomass Energy and Environmental Engineering Research Center Beijing University of Chemical TechnologyBeijing 100029China College of Chemical Engineering Beijing University of Chemical TechnologyBeijing 100029China Department of Chemical and Biochemical Environmental Engineering Technical University of DenmarkDK-2800Kgs LyngbyDenmark Energy Research Institute Qilu University of Technology(Shandong Academy of Sciences)Shandong Provincial Key Laboratory of Biomass Gasification TechnologyJinan 250014China

Utilizing CO_(2)for bio-succinic acid production is an attractive approach to achieve carbon capture and recycling(CCR)with simultaneous production of a useful platform *** succinogenes and Basfia succiniciproducens were selected and investigated as microbial ***,the type and concentration of inorganic carbon concentration and glucose concentration were evaluated.6 g C/L mgCO_(3)and 24 g C/L glucose were found to be the optimal basic operational conditions,with succinic acid production and carbon yield of over 30 g/L and over 40%,***,for maximum gaseous CO_(2)fixation,carbonate was replaced with CO_(2)at different ***“less carbonate more CO_(2)”condition of the inorganic carbon source was set as carbonate:CO_(2)=1:9(based on the mass of carbon).This condition presented the highest availability of CO_(2)by well-balanced chemical reaction equilibrium and phase equilibrium,showing the best performance with regarding CO_(2)fixation(about 15 mg C/(L·hr)),with suppressed lactic acid *** to key enzymes analysis,the ratio of phosphoenolpyruvate carboxykinase to lactic dehydrogenase was enhanced at high ratios of gaseous CO_(2),which could promote glucose conversion through the succinic acid *** further increase gaseous CO_(2)fixation and succinic acid production and selectivity,stepwise CO_(2)addition was evaluated.50%-65%increase in inorganic carbon utilization was obtained coupled with 20%-30%increase in succinic acid *** was due to the promotion of the succinic acid branch of the glucose metabolism,while suppressing the pyruvate branch,along with the inhibition on the conversion from glucose to lactic acid.

关键词： Succinic acid CO_(2) fixation Actinobacillus succinogenes Basfia succiniciproducens Lactic acid

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Chemoselective and Living/Controlled Polymerization of Alkenyl methacrylates by the Phosphonium Ylide/Organoaluminum Lewis Pairs

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Chinese Journal of Polymer Science 2024年第2期42卷 159-167,I0005页

作者： Zhi-Kang Chen Wu-Chao zhao Yi-Ling zhao Cong-Lei Liu Liu-Yin Jiang Yue-Tao Zhang Hong-Ping Zhu State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China State Key Laboratory of Supramolecular Structure and materials College of ChemistryJilin UniversityChangchun130012China

Chemoselective,living/controlled polymerizations of allyl methacrylate(AmA) and vinyl methacrylate(VmA) with/without methyl methacrylate(mmA) by using the phosphonium ylide/organoaluminum based Lewis pairs(LPs) have been *** P-ylide-2/AIme(BHT)_(2)(Pylide-2=Ph_(3)P=CHme and BHT=2,6-iBu_(2)-4-meC_(6)H_(2)O) was demonstrated to be superior by which homopolymers PAmAs(m_(n)=27.6-111.5kg/mol and ■=1.14-1.25) and PVmAs(m_(n)=28.4-78.4 kg/mol and ■=1.12-1.18) and block copolymers PmmA-b-PAmA,PAmA-b-PVmA,PAmA-bPmmA,PmmA-b-PAmA-b-PmmA,PAmA-b-PmmA-b-PAmA,and PAmA-b-PVmA-b-PAmA were *** the polymerizations,all of the monomers were reacted by the conjugated ester vinyl groups leaving intactly the nonconjugated acryloxy *** pendant acryloxy groups attached to the main chain enable further to post-functionalization by the AIBN-induced radical "thiol-ene" reaction using PhCH_(2)*** thiolether side group-containing polymers PAmA-SCH_(2)Ph and PAmA-SCH_(2)Ph-b-PmmA-b-PAmA-SCH_(2)Ph were thus prepared.

关键词： Phosphonium ylide Alkenyl methacrylate Chemoselectivity Living/controlled polymerization Post-functionalization

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Relativistic configuration-interaction density functional theory:Nonaxial effects on nuclear ββ decay

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Science Bulletin 2024年第13期69卷 2017-2020页

作者： Yakun Wang Pengwei zhao Jie meng State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China

Nuclear ββ decay is a second-order weak process in which an even-even nucleus decays to its neighboring even-even nucleus by turning two neutrons to two protons while emitting two electrons.A nucleus undergoes such ... 详细信息

关键词： decay neighboring interaction

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Hollow structured Fe@C nanorods for boosting dehydrogenation properties ofα-AlH_(3)

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Nano Research 2024年第9期17卷 8184-8191页

作者： Yuan zhao Qingshuang Wang Dongming Yin Xiaoli Wang Shouliang Li Chunli Wang Long Liang Shaolei zhao Limin Wang Yong Cheng School of materials Science and Engineering Changchun University of Science and TechnologyChangchun 130022China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Shandong Provincial Key Laboratory of monocrystalline Silicon Semiconductor materials and Technology College of Chemistry and Chemical EngineeringDezhou UniversityDezhou 253023China Henan Nayu New material Co. Ltd.Xinxiang 453000China

α-AlH_(3)is regarded as one of the most promising hydrogen storage materials due to its high hydrogen storage capacity(10.1 wt.%,148 kg·m^(-3)).However,in practical applications,the associated hydrogen release temperature remains relatively *** effectively address this issue,hollow structured Fe@C nanorods derived from Fe-mOF are introduced as highly efficient catalyst to optimize the dehydrogenation properties ofα-AlH_(3).Comparatively,the initial hydrogen release temperature ofα-AlH_(3)+3 wt.%Fe@C is reduced to 94.2℃,which is significantly lower than that of pureα-AlH_(3)(137.8℃).At 100 and 120℃,it exhibits hydrogen capacities of 5.38 wt.%and 7.47 wt.%,respectively,whereas pureα-AlH_(3)only delivers hydrogen capacities of 0.24 wt.%and 5.94 wt.%under the same *** density functional theory(DFT)calculations further indicate that the existence of Fe@C catalyst can make the length of Al-H bond increase,which is more conducive to the release of *** results show that the synergistic effect of Fe and porous carbon in Fe@C nanorods can improve the hydrogen desorption kinetics ofα-AlH_(3),providing a good prospect for the application ofα-AlH_(3)in hydrogen storage fields.

关键词： Fe@C α-AlH_(3) dehydrogenation catalyst

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Synthesis,structure,and thermal expansion in CaZrF6 with two polymorphs

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Nano Research 2024年第9期17卷 8618-8626页

作者： Peixian Zhang Yongqiang Qiao Kaiyue zhao Qingjie Wang Huan zhao Juan Guo Erjun Liang Tao Sun Jiangwei Zhang Qilong Gao Key Laboratory of materials Physics of ministry of Education School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China College of Energy materials and Chemistry Inner Mongolia UniversityHohhot 010021China First Affiliated Hospital of Dalian medical University 222 Zhongshan RoadDalian 116011China Ordos Laboratory Ordos 017000China

Due to the high structural flexibility and controllable thermal expansion,cubic double ReO_(3)-type negative thermal expansion(NTE)fluorides provide a solution for solving the prominent phenomenon of thermal expansion mismatch between ***,the expensive raw materials and complex synthesis steps limit its practical *** this work,we have designed a more advantageous method for the synthesis of NTE material CaZrF6,and it is expected to be generalized to the synthesis of other double ReO_(3)-***,a new orthorhombic phase CaZrF6 has been synthesized via this method in a lower *** the strong isotropic NTE of the cubic phase CaZrF6,the orthorhombic phase shows the strong anisotropic positive thermal expansion(PTE).The combined analysis of temperature-dependent X-ray diffraction(XRD),Raman spectra,and first-principles calculations shows that the low frequency phonon vibration mode with negative Grüneisen parameter in cubic CaZrF6 are strongly correlated with the transverse thermal vibration of F atoms and dominates the NTE of the material.

关键词： negative thermal expansion fluorides polymorph lattice dynamics first principles calculations

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