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Effective assignment of positional isomers in dimeric shikonin and its analogs by ^(1)H NMR spectroscopy

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Chinese Chemical Letters 2024年第5期35卷 223-226页

作者： Ling-Hao Zhao Hai-Wei Yan Jian-shuang Jiang Xu zhang Xiang Yuan Ya-nan Yang Pei-Cheng zhang State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China

An approach for distinguishing two types of positional isomers of dimeric shikonin and its analogs was explored with ^(4)JC,H long-range correlation by prolonging the acquisition time at ^(2,3)JC,H values of 2.0 and ***,the ^(1)H(proton)nuclear magnetic resonance(NMR)pattern of phenolic hydroxyl protons was developed as a“diagnosis signal”to ascertain the relative location of each side chain in DMSO-d_(6) at sample concentrations of 0.022-0.034 mol/*** chemical shift differences of 0.6ppm between OH-5' and OH-1 and between OH-8'and OH-4 are assigned to Type A and Type B,*** reported ambiguous structures were corrected by this ***,the steric structures of isolated compounds were elucidated by quantum chemical calculations of electronic circular dichroism(ECD)spectra.

关键词： Arnebia euchroma Dimeric hydroxyl naphthoquinones Positional isomers ^(1)H NMR spectroscopy Chemical shift difference

Dynamic Modeling and Experimental Verification of an RPR Type Compliant Paralle Mechanism with Low Orders

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 83-94页

作者： shuang zhang Jingfang Liu Huafeng Ding Yanbin zhang School of Mechatronics Engineering Henan University of Science and TechnologyLuoyangHenanChina Faculty of Materials and Manufacturing College of Mechanical Engineering and Applied Electronics TechnologyBeijing University of TechnologyBeijingChina Key laboratory of advanced manufacturing technology Beijing University of TechnologyBeijingChina School of Mechanical Engineering and Electronic Information China University of Geosciences(Wuhan)WuhanChina Center of Machinery Equipment Advanced Manufacturing of Henan Province LuoyangChina

Efficiency of calculating a dynamic response is an important point of the compliant mechanism for posture *** modeling with low orders of a 2R1T compliant parallel mechanism is studied in the *** mechanism with two out-of-plane rotational and one lifting degrees of freedom(DoFs)plays an important role in posture *** on elastic beam theory,the stiffness matrix and mass matrix of the beam element are established where the moment of inertia is *** improve solving efficiency,a dynamic model with low orders of the mechanism is established based on a modified modal synthesis ***,each branch of the RPR type mechanism is divided into a ***,a set of hypothetical modes of each substructure is obtained based on the C-B ***,dynamic equation of the whole mechanism is established by the substructure assembly.A dynamic experiment is conducted to verify the dynamic characteristics of the compliant mechanism.

关键词： Compliant parallel mechanism Dynamic model Modal synthesis method Dynamic experiment

Quantum gate-assisted teleportation in noisy environments:robustness and fidelity improvement

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Communications in Theoretical Physics 2024年第1期76卷 36-48页

作者： Sajede Harraz Jiaoyang zhang shuang Cong Department of Automation University of Science and Technology of ChinaHefei 230027China

Quantum teleportation as the key strategy for quantum communication requires pure maximally shared entangled states among quantum *** practice,quantum decoherence drastically degrades the shared entanglement during entanglement distribution,which is a serious challenge for the development of quantum ***,most of the decoherence control strategies proposed thus far are either resource-intensive or *** overcome this obstacle,we enable noise-resistant teleportation through a noisy channel with a limited number of qubits and without applying time-consuming weak *** apply a quantum gate control unit consisting of a controlled NOT gate and a rotation gate after the original teleportation protocol is ***,we demonstrate that a teleportation fidelity of unity is attainable when environment-assisted measurement is added to the proposed teleportation protocol via quantum ***,we present an entanglement distribution process by employing the designed quantum gate control unit followed by the deterministic standard teleportation protocol to improve teleportation fidelity by establishing improved shared *** performance analysis indicates that the proposed teleportation schemes offer a competitive fidelity and success probability compared with the conventional schemes and a recent weak measurement-based teleportation protocol.

关键词： quantum communication quantum teleportation decoherence control quantum gate environment-assisted measurement

An effective strategy of constructing multi-metallic oxides of ZnO/ CoNiO_(2)/CoO/C microflowers for improved supercapacitive performance

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Chinese Journal of Chemical Engineering 2024年第3期67卷 1-8页

作者： Wei Guo Yan zhang Xiaxin Lei shuang Wang College of Physics Taiyuan University of TechnologyJinzhong 030600China College of Environmental Science and Engineering Taiyuan University of TechnologyJinzhong 030600China Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization Taiyuan University of TechnologyTaiyuan 030024China

In this work,a new ZnO/CoNiO_(2)/CoO/C metal oxides composite is prepared by cost-effective hydrothermal method coupled with annealing process under N_(2) ***,the oxidation-defect annealing environment is conducive to both morphology and component of the composite,which flower-like ZnO/CoNiO_(2)/CoO/C is *** from good chemical stability of ZnO,high energy capacity of CoNiO_(2) and CoO and good conductivity of C,the as-prepared sample shows promising electrochemical behavior,including the specific capacity of 1435 C·g^(-1) at 1 A·g^(-1),capacity retention of 87.3%at 20 A·g^(-1),and cycling stability of 90.5%for 3000 cycles at 5 A·g^(-1),***,the prepared ZnO/CoNiO_(2)/CoO/C/NF//AC aqueous hybrid supercapacitors device delivers the best specific energy of 55.9 W·h·kg^(-1) at 850 W·kg^(-1).The results reflect that the as-prepared ZnO/CoNiO_(2)/CoO/C microflowers are considered as high performance electrode materials for supercapacitor,and the strategy mentioned in this paper is benefit to prepare mixed metal oxides composite for energy conversion and storage.

关键词： Composites Electrochemistry Hydrothermal Transition metal oxides Structural control Supercapacitors

Intelligent secure near-field communication

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Science China(Information Sciences) 2024年第9期67卷 340-341页

作者： nan zhang Jifa zhang Chengwen XING Na DENG nan ZHAO School of Information and Communication Engineering Dalian University of Technology School of Information and Electronics Beijing Institute of Technology

The research and development efforts for the sixth generation(6G) wireless communication are underway to fulfill the growing demands for wireless communications. 6G is expected to become the key enabler for diverse new applications and services [1]. To achieve the excellent performance, 6G will implement extremely large-scale antenna arrays(ELAAs), terahertz [2], and new types of antennas with metamaterials, leading to a paradigm shift for the electromagnetic characteristics.

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Neosophoflavonoids A–C, A class of highly oxidized hybrid flavonoids from Sophora flavescens with antidiabetic effects

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Chinese Chemical Letters 2024年第10期35卷 321-324页

作者： Xu zhang Jiang Li Kai-Zhou Lu Ya-nan Yang Jian-shuang Jiang Xiang Yuan Zi-Ming Feng Fei Ye Pei-Cheng zhang State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia Medica Chinese Academy of Medical Sciences and Peking Union Medical College

Three highly oxidized hybrid flavonoids neosophoflavonoids A–C（1, 2a, and 2b） were isolated from the roots of Sophora flavescens. Neosophoflavonoid A possesses a unique highly oxidized heptacyclic6/6/6/6/6/6/5 system. Neosophoflavonoids B and C are isomers and share the same highly oxidized hexacyclic 6/6/6/6/6/6 systems. Their planar structures were elucidated from 1D/2D nuclear magnetic resonance（NMR）, ultraviolet spectroscopy（UV）, infrared spectroscopy（IR）, and high resolution electrospray ionization mass spectroscopy（HRESIMS） data. Their absolute configurations were determined by thorough GIAO13C NMR（DP4+） calculation protocol and electronic circular dichroism（ECD） calculation *** plausible biosynthetic routes for the compounds were also proposed. All compounds exhibited significant protein tyrosine phosphatase-1B（PTP1B） inhibitory activity with half maximal inhibitory concentration(IC50) values 3.94 ± 0.01, 0.38 ± 0.13, and 0.70 ± 0.01 μmol/L, respectively. In addition, compared to a positive control fenofibrate（Feno） at 20 μmol/L, compounds 2a and 2b exhibited stronger inhibitory effects on lipid accumulation in the oleic acid（OA）-induced cell model at 5 and 10 μmol/L.

关键词： Highly oxidized hybrid flavonoids Lipid accumulation inhibition Neosophoflavonoids A–C PTP1B inhibition Sophora flavescens

Anti-saturation fault-tolerant adaptive torsional vibration control with fixed-time prescribed performance for rolling mill main drive system

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Journal of Iron and Steel Research International 2024年第3期31卷 660-669页

作者： shuang Liu Chen Du Cong zhang Zhen-hua Bai Key Lab of Industrial Computer Control Engineering of Hebei Province Yanshan UniversityQinhuangdao 066004HebeiChina National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina

An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter ***,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the ***,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter *** on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation *** to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric ***,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.

关键词： Fixed-time prescribed performance Control input saturation Actuator fault Unknown time-varying gain Adaptive control Asymmetric constraint

A bifunctional POM-based Cu-viologen complex with mixed octamolybdate clusters for rapid oxidation desulfurization and effective photogeneration of hydrogen

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Rare Metals 2024年第1期43卷 236-246页

作者： Lin Yang Zhong zhang Chao-nan zhang Xiu-Li Wang College of Chemistry and Materials Engineering Bohai UniversityJinzhou 121013China Professional Technology Innovation Center of Liaoning Province for Conversion Materials of Solar Cell Bohai UniversityJinzhou 121013China

The design and synthesis of catalysts for the oxidation desulfurization and production of hydrogen are extremely important for solving environmental pollution and energy ***,a novel bifunctional [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)-based Cu-viologen complex H_(4)[Cu_(2)~ⅠCl_(2)(Hbcbpy)_(4)] [α-Mo_(8)O_(26)] [β-Mo8O_(26)]·H_(2)O(BHU-2,Hbcbpy=1-(4-carboxybenzyl)-4,4'-bipyridinium) was synthesized and characterized by single-crystal X-ray diffraction(XRD),infrared radiation spectra,powder X-ray diffraction(PXRD) and X-ray photoelectron spectroscopy(XPS) *** structural characteristic of BHU-2 is the presence of two types of octamolybdate clusters [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)and a new binuclear Cu~Ⅰ-Hbcbpy complex linked by Cl-bridges[Cu_(2)ⅠCl_(2)(Hbcbpy)_(4)]^(4+).BHU-2 as a heterogeneous catalyst exhibits excellent activities to the oxidation desulfurization and photocatalytic hydrogen *** room temperature,BHU-2 can catalyze 96% conversion of methyl phenyl sulfide with 98% selectivity,and the process obeys the pseudo-first-order reaction kinetic with the half-life of9.6 *** notorious 2-chloroethyl ethyl sulfide can achieve 99% conversion with 98% selectivity within only1 min at the presence of BHU-2,and the turnover frequency(TOF) is up to 7400 h^(-1).BHU-2 also exhibits high catalytic activity for the oxidation of other aromatic and aliphatic thioethers within short time at room ***,BHU-2 shows a high catalytic activity for visible-light-driven hydrogen evolution with an H_(2) evolution rate of 1677.85 μmol·g^(-1)·h^(-1) within 10 ***,the catalytic activities do not decrease evidently after three cycles,revealing the prominent structural stability and recyclability.

关键词： Polyoxometalate Metal-organic complex Viologen Oxidation desulfurization Photocatalytic hydrogen production

Tailoring microenvironment for efficient CO_(2)electroreduction through nanoconfinement strategy

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nano Research 2024年第9期17卷 7880-7899页

作者： Lulu Chen Minhan Li Jia-nan zhang Key Laboratory of Advanced Energy Catalytic and Functional Materials Preparation Country College of Materials Science and EngineeringZhengzhou UniversityZhengzhou 450001China

The electrocatalytic conversion of CO_(2)to produce fuels and chemicals holds great promise,not only to provide an alternative to fossil feedstocks,but also to use renewable electricity to convert and recycle the greenhouse gas CO_(2)to mitigate climate ***,the selectivity and reaction rates for the conversion of CO_(2)into desirable carbon-based products,especially multicarbon products with high added value,are still insufficient for commercial applications,which is attributed to insufficiently favourable microenvironmental conditions in the vicinity of the *** construction of catalysts/electrodes with confined structures can effectively improve the reaction microenvironment in the vicinity of the electrodes and thus effectively direct the reaction towards the desired *** this review,we firstly introduce the effects of the microenvironment at the electrode-electrolyte interface including local pH,local intermediate concentration,and local cation concentration on CO_(2)reduction reaction(CO_(2)RR)as well as the mechanism of action,and then shed light on the microenvironmental modulation within the confined space,and finally and most importantly,introduce the design strategy of CO_(2)RR catalyst/electrode based on the confinement effect.

关键词： CO_(2)reduction reaction microenvironment confinement effect catalyst design