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Rotordynamic prediction of mode order transition when rotor has an overhang

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航空动力学报 2015年第2期30卷 397-409页

作者： Konstantin Shaposhnikov HONG Jie zhang Da-yi MA Yan-hong School of Energy and Power Engineering Beijing University of Aeronautics and Astronautics

Nowadays rotating machinery grows and develops extremely fast due to its multi-branch *** the fields of rotordynamics and rotor balancing had a strong background based on previous experience in order to perform efficient and safe operation for the rotating machines,still there are problems which are hard to be dealt with in some special *** of them is balancing of the rotor with huge *** with overhang is inherent to have console modes,which previously often were observed separately from the other modes in rotordynamic *** such a way console modes,their behavior,order of appearance and interaction with other modes were described in current paper in more *** results confirmed that console modes obey the principle of orthogonality in the same way as all other modes and hence could be efficiently balanced using modal balancing *** results revealed likelihood of such phenomena as modes order transition,when the rotor has an *** a consequence perfectly balanced console rotor could not be so due to modes order transition effect when the bearing stiffness in situ differs from bearing stiffness of balancing *** results will be useful for engineers who are involved in area of rotating machinery vibration tuning for the rotor with huge overhang and benefit them to recognize these modes efficiently and to perform balancing successfully.

关键词：疲劳寿命分散性顺序统计量寿命分散系数小子样

SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF 3,6-DISUBSTITUTED S-TRIAZOLO[3,4-b]-1,3,4-THIADIAZOLES

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Chinese Chemical Letters 1991年第4期2卷 277-278页

作者： Zi yi zhang xin CHEN Department of Chemistry,Lanzhou University,Lanzhou 730000

A series of 3,6-disubstituted s-triazolo[3,4-b]-1,3,4-thiadiazoles have been synthesized,whose structures were determined by elemental and spectral analyses;all the new compounds showed significant antibacterial activ... 详细信息

关键词： DMF 甲酰胺 SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF 3,6-DISUBSTITUTED S-TRIAZOLO[3,4-b THIADIAZOLES

Integrating photocatalytic reduction of CO2 with selective oxidation of tetrahydroisoquinoline over InP–In2O3 Z-scheme p-n junction

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Science China Chemistry 2020年第1期63卷 28-34页

作者： Bohang Zhao yi Huang Dali Liu yifu Yu Bin zhang Department of Chemistry Tianjin Key Laboratory of Molecular Optoelectronic SciencesSchool of ScienceTianjin UniversityTianjin 300072China Institute of Molecular Plus Tianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China

The development of a facile strategy to construct stable hierarchal porous heterogeneous photocatalysts remains a great challenge for efficient CO2 ***,hole-trapping sacrificial agents(e.g.,triethanolamine,triethylamine,and methanol)are mostly necessary,which produce useless chemicals,and thus cause costs/environmental ***,utilizing oxidation ability of holes to develop an alternative photooxidation reaction to produce value-added chemicals,especially coupled with CO2 photoreduction,is highly ***,an in situ partial phosphating method of In2O3 is reported for synthesizing In P–In2O3 p-n junction.A highly selective photooxidation of tetrahydroisoquinoline(THIQ)into value-added dihydroisoquinoline(DHIQ)is to replace the hole driven oxidation of typical sacrificial ***,the photoelectrons of In P–In2O3 p-n junction can induce the efficient photoreduction of CO2 to CO with high selectivity and *** evolution rates of DHIQ and CO are 2 and 3.8 times higher than those of the corresponding In2O3 n-type precursor,*** situ irradiated X-ray photoelectron spectroscopy and electron spin resonance are utilized to confirm that the direct Z-scheme mechanism of In P–In2O3 p-n junction accelerate the efficient separation of photocarriers.

关键词： CO2 reduction dehydrogenation photocatalysis Z-scheme tetrahydroisoquinoline

Different prognostic association of systolic blood pressure at different time points with postdischarge events in patients hospitalized for decompensated heart failure

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Journal of Geriatric Cardiology 2019年第9期16卷 676-688,I0006-I0009页

作者： You-Nan YAO Rong-Cheng zhang Tao AN Qi zhang xin-Ke ZHAO Jian zhang State Key Laboratory of Cardiovascular Disease Heart Failure Care Unit of Fuwai Hospital National Center for Cardiovascular Diseases Chinese Academy of Medical Sciences and Peking Union Medical College Beijing China The Affiliated Hospital of Gansu University of Chinese Medicine Lanzhou China

Background The association of systolic blood pressure(SBP) with mortality in heart failure(HF) patients is paradoxical, and the time points of baseline SBP are also different across prior studies. We hypothesized that the levels of SBP at admission and at discharge had different associations with postdischarge events. Methods The study population included patients hospitalized for decompensated HF in the Heart Failure Center of Fuwai Hospital from January 1, 2009 to December 31, 2014. The primary outcome was a composite of cardiovascular(CV) death and heart transplantation. Multivariate Cox proportional-hazards and restricted cubic spline analyses were used to assess the relationships between SBP at different time points and outcomes. Results In total, 2005 patients were included with a median follow-up of 48.4 months. The median age was 59 years, and 69.9% were male. Multivariate Cox analyses showed that compared with SBP < 105 mm Hg, higher SBP at admission was associated with better long-term primary outcome(105–119 mm Hg, HR = 0.764, P = 0.005;120-134 mm Hg, HR = 0.658, P < 0.001;≥ 135 mm Hg, HR = 0.657, P = 0.001). Patients whose discharge SBP was higher than 135 mm Hg had a similar primary outcome as those with SBP < 105 mm Hg(HR = 0.969, P = 0.867), and the results remained unchanged even after adjusting for admission SBP(HR = 1.235, P = 0.291). The results of restricted cubic spline analysis indicated similar associations. Conclusions Lower but not higher SBP at admission is associated with more CV deaths/heart transplantations(a reverse J-shaped curve). In contrast, there is a U-shaped association between discharge SBP and CV mortality/heart transplantation.

关键词： Admission Discharge Heart failure Outcome Systolic blood pressure

Hydrogen-Bonded Engineering Enhancing Phase Transition Temperature in Molecular Perovskite Ferroelastic

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Chinese Journal of Chemistry 2022年第13期40卷 1559-1565,I0002页

作者： Tie zhang Kun Ding Jun-yi Li Guo-Wei Du Lu-Lu Chu yi zhang Da-Wei Fu Ordered Matter Science Research Center Jiangsu Key Laboratory for Science and Applications of Molecular FerroelectricsSoutheast UniversityNanjingJiangsu211189China

The broad operating temperature range is sought for molecular ferroic materials who are expected to be applied to flexible and electronic *** bonds,an effective force between molecules,are important to regulate the molecule structure and their condition,helping a higher temperature range for ferroic ***,we report a molecular perovskite ferroelastic(Me-Hdabco)Rb[BF_(4)]_(3)(Me-Hdabco=N-methyldabconium)which shows high temperature(T_(1)=322.5 K and T_(2)=381K)ferroelastic phase *** ferroelastic phase transition temperature range of(Me-Hdabco)Rb[BF_(4)]_(3) is significantly increased by 71 K compared with[Meda-bco-F]Rb[BF_(4)]_(3)(Medabco-F=1-fluoro-4-methyl-1,4-diazoniabicyclo[2.2.2]octane).Structural analysis and thermal analysis demonstrate the ferroelastic phase transition is mainly attributed to dynamic cations order and disorder ***,new hydrogen bonds generated between cations and the Rb_(8)[BF_(4)]_(12) frame increase their intermolecular force,which is beneficial to improving the phase transition *** finding has an important impact on the utilization of weak interactionforces to design and optimize functional materials.

关键词： Molecular dynamics Ferroelastic crystal Dielectric Hydrogen bonds Phase transitions

Achieving an ion-homogenizing and corrosion-resisting interface through nitro-coordination chemistry for stable zinc metal anodes

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Journal of Energy Chemistry 2024年第7期94卷 10-18页

作者： Jizhen Wang Long Jiao Qiaoyun Liu Wei xin Yechen Lei Tian zhang Leixin Yang Dengkun Shu Shuo Yang Kaihua Li Chenyang Li Chao yi Hongyuan Bai Yuchao Ma Huan Li Wenjun zhang Bowen'Cheng schoolof Light Industry Science and Engineering State Key Laboratory of Biobased Fiber Manufacturing TechnologyTianjin Key Laboratory of Pulp and PaperChina Light Industry Key Laboratory of Papermaking and BiorefineryTianjin University of Science&TechnologyTianjin 300457China Department of Materials Science and Engineering &Center of Super-Diamond and Advanced FilmsCity University of Hong Kong83 Tat Chee AvenueHong Kong 999077China School of Chemical Engineering and Advanced Materials The University of AdelaideAdelaideSA 5005Australia

Suppression of uncontrollable dendrite growth and water-induced side reactions of Zn metal anodes is crucial for achieving long-lasting cycling stability and facilitating the practical implementations of aqueous Zn-metal *** address these challenges,we report in this study a functional nitro-cellulose interfacial layer(NCIL)on the surface of Zn anodes enlightened by a nitro-coordination chemistry *** NCIL exhibits strong zincophilicity and superior coordination capability with Zn^(2+)due to the highly electronegative and highly nucleophilic nature of the nitro functional *** characteristic facilitates a rapid Zn-ion desolvation process and homogeneous Zn plating,effectively preventing H_(2) evolution and dendrite ***,the negatively charged surface of NCIL acts as a shield,repelling SO_(4)^(2-)anions and inhibiting corrosive reactions on the Zn ***,reversible and stable Zn plating/stripping is achieved for over 5100 h at a current density of 1 mA cm^(-2),which is nearly 30 times longer than that of bare Zn ***,the Zn/V_(2)O_(5) full cells with the functional interface layer deliver a high-capacity retention of 80.3%for over 10,000 cycles at 5 A g^(-1).This research offers valuable insights for the rational development of advanced protective interface layers in order to achieve ultra-long-lifeZnmetal batteries.

关键词： Zinc metal anode Nitro-cellulose interfacial layer Coordination capability Dendrite-free deposition Long-term cycling

Two new diarylheptanoids from the pericarps of Juglans regia L.

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Chinese Chemical Letters 2007年第8期18卷 943-946页

作者： Jun Xi Liu Duo Long Di xin yi Huang Chen Li Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China

Two new cyclic diarylheptanoids juglanin A （1） and juglanin B （2） were isolated from the pericarps of Juglans regia L. Their structures were elucidated by various spectroscopic methods including 2D NMR techniques ... 详细信息

关键词： Juglans regia L. Pericarps Diarylheptanoids Juglanin A Juglanin B

A swept fin-induced flow field with different height mounting gaps

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Chinese Journal of Aeronautics 2021年第1期34卷 148-162页

作者： Feng zhang Shihe yi Xiwang XU Haibo NIU Xiaoge LU College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

In order to apply the air fin successfully and ensure the maneuverability of hypersonic vehicle, a key problem to be studied urgently is the heat flux brought by the fin mounting *** appearance of mounting gap and fin shaft can induce many complex flow structures which need more attentions to be investigated. Under Ma 6, Nano-tracer-based Planar Laser Scattering(NPLS)and Temperature Sensitive Paints(TSP) were applied to visualize and measure transient flow structures and heat flux distribution of a swept fin-induced flow field with different height mounting gaps. Complementarily, Reynolds-averaged N-S equations were solved with k-x SST turbulent model. The heat flux distribution results of numerical simulation and TSP observed the change of high heat flux region with different mounting gap, both in position and magnitude. The streamlines based on Computational Fluid Dynamics(CFD) and flow visualization results obtained by NPLS revealed the cause of high heat flux region. The high heat flux region in this flow field is mainly related to the reattachment of vortex and flow stagnation. The increase of gap height can lead to stronger gap overflow and shaft-induced horseshoe vortex, which are source of the high heat flux around the fin. The case with the highest mounting gap(4 mm) en-counters the most severe aerodynamic heating, both on the surface of fin and plate. Thus, under the premise of ensuring the flexibility of the fin, the gap should be set as small as possible.

关键词： Fin Flow visualization Heat flux Hypersonic Shock/boundary layer interaction Temperature sensitive paint

Preparation of CaB6 powder via calciothermic reduction of boron carbide

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International Journal of Minerals,Metallurgy and Materials 2020年第1期27卷 37-45页

作者： Yu Wang Guo-hua zhang Yue-dong Wu xin-bo He State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China

The method of calciothermic reduction of B4C was proposed for preparing *** phase transition and morphology evolution during the reaction were investigated in *** experimental results reveal that Ca first reacts with B4C to generate CaB2C2 and CaB6 at a low temperature and that the CaB2C2 subsequently reacts with Ca to produce CaB6 and CaC2 at a high *** the products were leached to remove the byproduct CaC2,pure CaB6 was *** grain size of the prepared CaB6 was 2–3μm,whereas its particle size was 4–13μm;it inherited the particle size of *** residual C content of the product was decreased to 1.03 wt%after the first reaction at 1173 K for 4 h and the second reaction at 1623 K for 4 h.

关键词： borides carbides particle size powders calcium hexaboride