Metal phthalocyanine with a unique π-conjugated structure, has shown extraordinary promise for electrocatalysis, batteries and supercapacitors. High-performance Zn-ion hybrid supercapacitors make high demands on the energy storage mechanisms of metal phthalocyanine. We propose a β-form zinc phthalocyanine (ZnPc) molecular crystal as a cathode material for flexible Zn-ion hybrid supercapacitors. The β-ZnPc is facilely synthesized through the annealing treatment of the original ZnPc, which is previously fabricated through a ring-closure reaction assisted by catalysis of sodium methanol and ultrasonic treatment. The structural transformation of ZnPc from α-ZnPc to β-ZnPc is demonstrated at the annealing temperature from 200 °C to 300 °C, probably attributed to the short-range neighbor interaction between the adjacent layers. The β-ZnPc electrode exhibits higher specific capacitance and better rate capability than those of the α-ZnPc electrode, mainly due to its higher specific surface area and more abundant pore structure. The electron density of ZnPc and the adsorption energy for the adsorption of Zn2+ by ZnPc are theoretically calculated, revealing the active N atom sites for the reversible adsorption/desorption of Zn2+. The flexible Zn-ion hybrid supercapacitor provides the maximum energy densities of 86.2 Wh kg-1 at 0.22 kW kg-1, and maintains the capacitance retention of 73.4% after 100000 cycles, opening up a new avenue for developing high-energy and long-life Zn-ion hybrid supercapacitors.
The crystal structure of the title compound was determined by X-ray diffractometry.The complex crystallizes in monoclinic space group C2/c with Z= 8. Lattice parametersare: a =25.747(5), b= 8.461(0), c = 17.407(3)Å and β= 105.79(1)°. The structure wassolved by Patterson and Fourier techniques and refined by least-squares to a final R valueof 0.0283. The Zn(Ⅱ) ion is coordinated by three chloroligands and the atom N(1) of thepyrimidine ring of thiamine molecule, forming a slightly distorted tetrahedral coordinationpolyhedron. The average Zn-Cl distance is 2.266Å and the Zn-N bond length is2.042(4)Å.
Dear Sir,I have read with great interest the paper entitled ‘Association of trimethylamine N-Oxide with cardiovascular and all-cause mortality in hemodialysis patients’ by Zhang et al. [1]. Trimeth...
Leaf length is one of important parameters for crop growth estimation. In order to accurately obtain the plant leaf length, this paper proposes a slope linear hypothesis in which the leaf length could be measured in 3-D space with a right-angle model. A binocular stereo vision system was applied with RGB and depth image output. The projection of leaf could be obtained in RGB and depth image. The depth camera is used to obtain one right-angle side to correct the measurement result in RGB image. Four methods were present to compare the extract accuracy in the images. First, RGB images without leaf segmentation were used to extract leaf length (L1→) on the horizontal projection plane. Second, leaf length (L2→) were calculated with the right-angle model correction by depth image based on (L1→). Third, the preprocessing of RGB images was conducted with color image segmentation and morphological operation, then the leaf length (L3→) was extracted. Fourth, the correction leaf length (L4→) were obtained by depth image correction to L3→. Four prediction models were established to analyze L1→, L2→, L3→, and L4→ results. It is indicated that the prediction model based on the L2→ measurement has better performance, in which Rc2 is 0.7178 and Rv2 is 0.833.
Spin coating is a common method for fabricating polymer thin films on flat substrates. The well-established Meyerhofer relationship between film thickness (h) and spin rate (ω), h ∝ ω-1/2, enables the preparation of thin films with desired thickness by adjusting the spin rate and other experimental parameters. The 1/2 exponent has been verified by previous studies involving organic thin films prepared on silicon wafers. In this study, 88% and >99% hydrolyzed poly(vinyl alcohol) (PVOH) polymers were adsorbed and spin-coated from an aqueous solution onto four different substrates. The substrates were prepared by covalently attaching poly(dimethylsiloxane) (PDMS) of different molecular weights onto silicon wafers (SiO2). Atomic force microscopy images indicate that the PVOH films transitioned from stable on SiO2, to metastable, and then to unstable as PDMS molecular weight was increased. Notably, none of the polymer-substrate systems studied here exhibited the thickness-spin rate profile predicted by the Meyerhofer model. Based on the experimental results, a more general adsorption-deposition model is proposed that decouples the total spin-coated thickness into two components─the adsorbed thickness (h1) and the spin-deposited thickness (h2). The former accounts for polymer-substrate interactions, and the latter depends on polymer concentration and spin rate. In unstable systems, the exponents were found to be ∼0 because slip takes place at the solution-substrate interface during spin and the spin-deposited thickness is 0. In metastable and stable systems, a universal relationship between spin-deposited thickness and spin rate emerged, independent of the substrate type and polymer concentration for each polymer examined. Our findings indicate the importance of film stability and polymer-substrate interactions in the application of spin coating.
Correction for 'Preparation of conductive polyaniline grafted graphene hybrid composites via graft polymerization at room temperature' by Baoli Ou et al., RSC Adv., 2014, 4, 43212–43219.
Thread connections failture is the main factor for the drilling collar broking,which accounted for a large proportion of downhole accidents about drilling tools,in fact,fatigue is the mian reason for thread failture.The finite element models for collar's thread connection part with 2 types of thread were created,the stress distribution was analyzed in different WOB using linear elasticity finite element method,thread of box connection parts were optimized in structure for collars using API standard stress relief groove.Useing the R1 and R2,the radius of the transition fillets as two design parameters,the stress distribution were analyzed in the thread of box connection part in different R1 and R2 under certain conditions,The comparisons indicated that the im proved thread stress relief groove could reduce the stress concentration,the failture of drilling collar thread connections were resolved in Kurdistan.
Objective. To investigate the effect of cryotherapy using ice pops for physical analgesia and preventive analgesia using flurbiprofen axetil for pain management in children undergoing tonsillectomy. Methods. A total of 120 children scheduled for tonsillectomy were recruited after assessment for eligibility and assigned to a control group (group C), flurbiprofen axetil group (group F), cryotherapy group (group I), and cryotherapy plus flurbiprofen axetil group (Group FI) via the random number table method. Groups F and FI were given 1 mg/kg of flurbiprofen axetil through intravenous injection 30 min before surgery, while group C received an equal amount of saline at the same time point. Groups I and FI received sweet ice pops for pain relief after recovery from anesthesia. The modified Children’s Hospital of Eastern Ontario Pain Scale (mCHEOPS) scores and pediatric anesthesia emergence delirium (PAED) scores at 5 minutes (T1), 30 minutes (T2), 60 minutes (T3), 4 hours (T4), and 24 hours (T5) postoperatively, and the incidence of postoperative complications in the children were recorded by investigators who were masked to the grouping results. Results. From T1 to T4, significantly lower mCHEOPS scores and PAED scores were observed in group F, group I, and group FI versus those in group C ( P<0.05 ). At T2, group FI showed significantly lower mCHEOPS scores and PAED scores versus groups F and I ( P<0.05 ). There were no significant differences in the mCHEOPS scores and PAED scores between the four groups at 24 h postoperatively ( P>0.05 ). The differences in the documented postoperative complications between the four groups did not come up to the statistical standard ( P>0.05 ). Conclusion. Cryotherapy plus flurbiprofen axetil for pain management significantly mitigates post-tonsillectomy pain and delirium in children and facilitates recovery, with no significant adverse events.
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