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Tuning the cross-linked structure of basic poly(ionic liquid) to develop an efficient catalyst for the conversion of vinyl carbonate to dimethyl carbonate

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CHINESE jOURNAL Of CHEMICAL ENGINEERING 2024年第8期72卷 106-116页

作者： Qi, Zhaoyang Zhong, Shiquan Su, Huiyun Ye, Changshen Ren, Limei qiu, Ting Chen, jie fuzhou Univ Coll Chem Engn Fuzhou 350108 Peoples R China Qingyuan Innovat Lab Quanzhou 362801 Peoples R China fuzhou Univ Fuzhou Univ Int Joint Lab Thermochem Convers Bioma Fuzhou 350108 Peoples R China Shijiazhuang Univ Dept Chem Engn Shijiazhuang 050035 Peoples R China

Dimethyl carbonate (DMC) is a crucial chemical raw material widely used in organic synthesis, lithiumion battery electrolytes, and various other fields. The current primary industrial process employs a conventional sodium methoxide basic catalyst to produce DMC through the transesterification reaction between vinyl carbonate and methanol. However, the utilization of this catalyst presents several challenges during the process, including equipment corrosion, the generation of solid waste, susceptibility to deactivation, and complexities in separation and recovery. To address these limitations, a series of alkaline poly(ionic liquid)s, i.e. [DVBPIL][PHO], [DVCPIL][PHO], and [TBVPIL][PHO], with different crosslinking degrees and structures, were synthesized through the construction of cross-linked polymeric monomers and functionalization. These poly(ionic liquid)s exhibit cross-linked structures and controllable cationic and anionic characteristics. Research was conducted to investigate the effect of the crosslinking degree and structure on the catalytic performance of transesterification in synthesizing DMC. It was discovered that the appropriate cross-linking degree and structure of the [DVCPIL][PHO] catalyst resulted in a DMC yield of up to 80.6%. furthermore, this catalyst material exhibited good stability, maintaining its catalytic activity after repeated use five times without significant changes. The results of this study demonstrate the potential for using alkaline poly(ionic liquid)s as a highly efficient and sustainable alternative to traditional catalysts for the transesterification synthesis of DMC.

关键词： Poly(ionic liquid) Cross-linking degree Dimethyl carbonate production Transesterification reaction Mechanism ETHYLENE CARBONATE TRANSESTERIfICATION BIODIESEL ESTERIfICATION STABILITY METHANOL

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Ablative behavior and mechanism of SiC_(f) /SiBCZr composites prepared by PIP process

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journal of Advanced Ceramics 2024年第1期13卷 124-134页

作者： Mingwei Chen Yuliang Zhao Haipeng qiu Shijian Liu Weijie Xie Yi Chen Qiyue Zhang AVIC Manufacturing Technology Institute Beijing 100130China

SiC_(f)/SiBCZr composites were prepared by polymer precursor impregnation and pyrolysis process with near stoichiometric ratio SiC fiber preform as reinforcement phase and SiBCZr multiphase ceramic precursor as impregnating *** results highlighted that the SiC_(f)/SiBCZr composites exhibited excellent ablative properties after ablative tests at 1200℃/3600 s and 1400℃/3600 s,and the strength retention rates of the composites reached 90%and 85%,*** was mainly due to the liquid sealing effect of the ablative products represented by B2O_(3) and SiO_(2)∙B_(2)O_(3),which inhibited the ablative reaction by reducing the diffusion rate of the oxidation medium,and the solid pinning effect of the substances represented by SiO_(2),ZrO_(2),and ZrSiO_(4),which could play high viscosity and high strength characteristics to improve anti-erosion *** above-mentioned SiC_(f)/SiBCZr composites with corrosion resistance,oxidation resistance,and ablative resistance provided a solid material foundation and technical support for the development of reusable spacecraft hot-end components.

关键词： near stoichiometric ratio SiC fiber SiC_(f)/SiBCZr composite liquid sealing effect solid pinning effect

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Thermoluminescence characterization of natural and synthetic irradiated Ce-monazites

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journal of Rare Earths 2024年第4期42卷 643-650页

作者： V.Correcher C.Boronat j.Garcia-Guinea j.f.Benavente T.Rivera-Montalvo CIEMAT Av.Complutense 4028040MadridSpain MNCN-CSIC J.Gutierrez Abascal 228006MadridSpain Instituto Politécnico Nacional CICATA-IPNAv.Legaria 694Mexico City11500Mexico

The thermoluminescence(TL)emission of synthetic and natural Ce-monazites was characterized here to determine the potential application in the identification of microscopic defects from a qualitative point of view trying to link each TL peak to a chemical-physical *** kinetic parameters that lead the luminescence processes were calculated by means of variable heating rate and computing glow curve deconvolution methods and allow identifying three groups of components at~90,130 and 290℃(for the mineral sample)and~90,170,220,270 and 320℃(for the synthetic CePO_(4):Nd_(0.20),La_(0.25)).The main differences appreciated in these complex TL curves are mainly due to(i)the content of impurities(natural sample contains lanthanides as well as U 0.60%and Th 5.22%)and(ii)the degree of crystallinity of the samples which is directly related to the type of impurities(synthetic monazite relies only on Nd and La).The behavior of the dose response in the range of 1-8 Gy is similar for both samples;the TL intensity increases linearly as the dose increases without changes in the position of the maxima,denoting first-order kinetic luminescence *** peak could be mostly associated with structural defects(i.e.,phase transitions),chemical reactions(i.e.,Ce3+?Ce4+redox reaction,dehydration or dehydroxylation processes)or intrinsic defects(i.e.,frenkel defects,ODCs or NBOHCs).

关键词： Thermoluminescence Kineticparameters Phosphate Ce-monazite Defects Rare earths

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Resistive field generation in intense proton beam interaction with solid targets

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Matter and Radiation at Extremes 2024年第1期9卷 35-43页

作者： W.Q.Wang j.j.Honrubia Y.Yin X.H.Yang f.Q.Shao Department of Physics National University of Defense TechnologyHunanChina ETSI Aeronáutica y del Espacio Universidad Politécnica de MadridMadridSpain Department of Nuclear Science and Technology National University of Defense TechnologyHunanChina

The Brown-Preston-Singleton(BPS)stopping power model is added to our previously developed hybrid code to model ion beam-plasma *** simulations show that both resistive field and ion scattering effects are important for proton beam transport in a solid target,in which they compete with each *** the target is not completely ionized,the self-generated resistive field effect dominates over the ion scattering ***,when the target is completely ionized,this situation is ***,it is found that Ohmic heating is important for higher current densities and materials with high *** energy fraction deposited as Ohmic heating can be as high as 20%-30%.Typical ion divergences with half-angles of about 5°-10°will modify the proton energy deposition substantially and should be taken into account.

关键词： interaction beam intense

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On-chip spiking neural networks based on add-drop ring microresonators and electrically reconfigurable phase-change material photonic switches

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Photonics Research 2024年第4期12卷 755-766页

作者： QIANG ZHANG NING jIANG YIQUN ZHANG ANRAN LI HUANHUAN XIONG GANG HU YONGSHENG CAO KUN qiu School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

We propose and numerically demonstrate a photonic computing primitive designed for integrated spiking neural networks (SNNs) based on add-drop ring microresonators (ADRMRs) and electrically reconfigurable phasechange material (PCM) photonic switches. In this neuromorphic system, the passive silicon-based ADRMR,equipped with a power-tunable auxiliary light, effectively demonstrates nonlinearity-induced dual neural dynamics encompassing spiking response and synaptic plasticity that can generate single-wavelength optical neural spikes with synaptic weight. By cascading these ADRMRs with different resonant wavelengths, weighted multiple-wavelength spikes can be feasibly output from the ADRMR-based hardware arrays when external wavelengthaddressable optical pulses are injected;subsequently, the cumulative power of these weighted output spikes is utilized to ascertain the activation status of the reconfigurable PCM photonic switches. Moreover, the reconfigurable mechanism driving the interconversion of the PCMs between the resonant-bonded crystalline states and the covalent-bonded amorphous states is achieved through precise thermal modulation. Drawing from the thermal properties, an innovative thermodynamic leaky integrate-and-firing (TLIf) neuron system is proposed. With the TLIf neuron system as the fundamental unit, a fully connected SNN is constructed to complete a classic deep learning task:the recognition of handwritten digit patterns. The simulation results reveal that the exemplary SNN can effectively recognize 10 numbers directly in the optical domain by employing the surrogate gradient algorithm. The theoretical verification of our architecture paves a whole new path for integrated photonic SNNs, with the potential to advance the field of neuromorphic photonic systems and enable more efficient spiking information processing.

关键词： neural networks precise

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Early chatter identification based on optimized VMD with multi-band information fusion and compression method in robotic milling process

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Chinese journal of Aeronautics 2024年第6期37卷 464-484页

作者： Sichen CHEN Zhiqiang LIANG Yuchao DU Zirui GAO Haoran ZHENG Zhibing LIU Tianyang qiu Xibin WANG School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Undesirable self-excited chatter has always been a typical issue restricting the improvement of robotic milling quality and *** chatter identification based on processing signals can prompt operators to adjust the machining process and prevent chatter *** with the traditional machine tool,the uncertain multiple chatter frequency bands and the band-moving of the chatter frequency in robotic milling process make it more challenging to extract chatter *** paper proposes a novel method of chatter identification using optimized variational mode decomposition(OVMD)with multi-band information fusion and compression technology(MT).During the robotic milling process,the number of decomposed modes k and the penalty coefficient a are optimized based on the dominant component of frequency scope partition and fitness of the mode center ***,the mayfly optimization algorithm(MA)is employed to obtain the global optimal parameter *** order to conquer information collection about the uncertain multiple chatter frequency bands and the band-moving of the chatter frequency in robotic milling process,MT is presented to reduce computation and extract signal ***,the cross entropy of the image(CEI)is proposed as the final chatter indicator to identify the chatter *** robotic milling experiments are carried out to verify the proposed method,and the results show that it can distinguish the robotic milling condition by extracting the uncertain multiple chatter frequency bands and overcome the band-moving of the chatter frequency in robotic milling process.

关键词： Robotic milling Chatter detection Variational mode decomposition Information fusion and compression Chatter featur

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Influence of filler characteristics on particle removal in fluid catalytic cracking slurry under an alternating electric field

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Petroleum Science 2024年第3期21卷 2102-2111页

作者： Qiang Li Hui-Zhen Yang Can Yang Qing-Zhu qiu Wei-Wei Xu Zhao-Zeng Liu College of New Energy China University of Petroleum(East China)Qingdao266580ShandongChina

The characteristics of the packing material under an alternating electric field are an important factor in the removal of fCCS *** this study,the electric field distribution of a separation unit consisting of packed spheres under an alternating electric field is simulated,and the movement mechanism of catalyst particles is ***"effective contact point"model is derived to predict the adsorption of filler contact points on catalyst particles under the alternating electric field,and the model is validated by simulations and *** numerical calculation and experimental results indicate that the electrical properties of the filler spheres,the filler angleθ,and the frequency f of the alternating electric field affect the adsorption of catalyst *** the frequency of the electric field increases,the particle removal efficiency of the high-conductivity filler(silicon carbide)increases and then settles,and the separation efficiency of the low-conductivity filler(glass,zirconia)is not sensitive to the change in electric field frequency.

关键词： fluid catalyticcracking slurry(fCCS) Particle AC electric field fillers Removal

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Stochastic seismic inversion and Bayesian facies classification applied to porosity modeling and igneous rock identification

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Petroleum Science 2024年第2期21卷 918-935页

作者： fábio júnior Damasceno fernandes Leonardo Teixeira Antonio fernando Menezes freire Wagner Moreira Lupinacci Exploratory Interpretation and Reservoir Characterization Group(GIECAR) Department of Geology and GeophysicsFederal Fluminense UniversityNiter oiRJ24210-346Brazil Petrobras Rio de JaneiroRJ20231-030Brazil National Institute of Science and Technology of Petroleum Geophysics(INCT-GP/CNPQ) Niter oiRJ24210-346Brazil

We apply stochastic seismic inversion and Bayesian facies classification for porosity modeling and igneous rock identification in the presalt interval of the Santos Basin. This integration of seismic and well-derived information enhances reservoir characterization. Stochastic inversion and Bayesian classification are powerful tools because they permit addressing the uncertainties in the model. We used the ES-MDA algorithm to achieve the realizations equivalent to the percentiles P10, P50, and P90 of acoustic impedance, a novel method for acoustic inversion in presalt. The facies were divided into five: reservoir 1,reservoir 2, tight carbonates, clayey rocks, and igneous rocks. To deal with the overlaps in acoustic impedance values of facies, we included geological information using a priori probability, indicating that structural highs are reservoir-dominated. To illustrate our approach, we conducted porosity modeling using facies-related rock-physics models for rock-physics inversion in an area with a well drilled in a coquina bank and evaluated the thickness and extension of an igneous intrusion near the carbonate-salt interface. The modeled porosity and the classified seismic facies are in good agreement with the ones observed in the wells. Notably, the coquinas bank presents an improvement in the porosity towards the top. The a priori probability model was crucial for limiting the clayey rocks to the structural lows. In Well B, the hit rate of the igneous rock in the three scenarios is higher than 60%, showing an excellent thickness-prediction capability.

关键词： Stochastic inversion Bayesian classification Porosity modeling Carbonate reservoirs Igneous rocks

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ITPK1 is an InsP_(6)/ADP phosphotransferase that controls phosphate signaling in Arabidopsis

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Molecular Plant 2024年第7期17卷 1151-1157页

作者： Esther Riemer Danye qiu Debabrata Laha Robert K.Harmel Philipp Gaugler Verena Gaugler Michael frei Mohammad-Reza Hajirezaei Nargis Parvin Laha Lukas Krusenbaum Robin Schneider Adolfo Saiardi Dorothea fiedler Henning j.jessen Gabriel Schaaf Ricardo f.H.Giehi 不详

(Molecular Plant 14,1864-1880;November 12021)We identified a mistake made when calculating the absolute concentrations of inositol(pyro)phosphates derived from CE-ESl-MS measurements reported in the originally published version of our *** to a calculation error when determining concentrations per fresh biomass,the absolute values shown in the manuscript are approximately 30-fold lower than they should *** mistake affects figures 2D,3C,4C,and 7D and figures S4,S11B,S13,and *** all conclusions made in the article referred to relative differences between genotypes and treatments,they remained unaffected by these mistakes.

关键词： ipt Arabidopsis absolute

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Highly Stable sp^(2) Carbon-Conjugated Porous Organic Cages

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CCS Chemistry 2024年第1期6卷 149-156页

作者： fenglei qiu Xun Chen Wenjing Wang Kongzhao Su Daqiang Yuan State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian 350002 College of Chemistry Fuzhou UniversityFuzhouFujian 350116 University of the Chinese Academy of Sciences Beijing 100049

The high-yield synthesis of ultrastable porous organic cages(POCs)by facile methods is highly desirable but *** by highly stable sp^(2) carbon-conjugated(C=C)covalent organic frameworks,we used rational design and synthesized the first family of sp^(2) carbon-linked POCs(sp^(2)c-POCs)with triangular prism shapes by a one-step Knoevenagel reaction that is a high yield[2+3]condensation *** stability of sp^(2)c-POC was demonstrated under strenuous conditions involving for example concentrated HCl or saturated NaOH ***^(2)c-POC was used as a robust adsorbent for efficient separation of CO_(2)/CH_(4) or CO_(2)/N_(2) *** view of their facile synthesis and unique properties,we expect widespread use of these sp^(2) C=C linkages in the development of POC materials.

关键词： porous organic cages Knoevenagel condensation sp^(2)C=C linkage exceptional chemical stability gas adsorption and separation properties

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