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Three Hall-effect sensors can be used to estimate the continuous rotor position of permanent magnet synchronous motors (PMSMs) at a low cost. However, available position estimation methods generally require motor model parameters or have a phase offset. For this purpose, this article proposes a harmonic-decomposition complex-coefficient filter-based phase-locked loop (HD-CCF-PLL) structure that is independent of motor parameters and has a near-zero phase offset. First, the triggering principle of Hall-effect sensors is introduced, and the effect of Hall position error on current harmonics and torque ripples is analyzed. Then, coordinate transformation and harmonic decomposition methods are presented for three Hall-effect sensors. However, there is a limit to the number of times a microcontroller can perform real-time harmonic decomposition. The decomposed Hall position vector still contains high-order harmonics, which reduces position estimation accuracy. Therefore, a CCF-PLL technique is employed to filter out these harmonics and estimate the rotor position. An efficient method of CCF-PLL online parameter self-adjustment is also provided for adapting to different speeds. Finally, the effectiveness of the proposed method is verified by detailed experiments. The results show that the proposed method can effectively filter out the harmonics in the Hall position vector with higher position estimation accuracy, fewer current total current harmonic distortion, and a smaller torque ripple than the existing method.

SO2is considered as the most poisonous ambient contaminant to proton exchange membrane fuel cell (PEMFC) cathodes, leading to severe Pt deactivation and oxygen reduction reaction (ORR) performance loss. Great efforts have been devoted to studying the deactivation and regeneration of SO2-poisoned Pt/C catalysts, but far less to cases with coexisting NO. Herein, the deactivation and regeneration processes of Pt surfaces during ORR in the presence of both SO2and NO (in different molar ratios) are investigated by means of in situelectrochemical infrared spectroscopy and density functional theory (DFT) calculations. Interestingly, NO presents a stronger affinity to Pt sites than SO2—if an appropriate NO : SO2ratio is applied, SO2adsorption can be completely inhibited. Besides, the competitive adsorption of NO can weaken the Pt–S bond and expel adsorbed SO2. Given that adsorbed NO is readily reduced, a faster regeneration is observed if NO and SO2are simultaneously fed into the cathode.

A solid electrolyte interphase (SEI) with a robust mechanical property and a high ionic conductivity is imperative for high-performance zinc metal batteries. However, it is difficult to form such a SEI directly from an electrolyte. In this work, a molecular crowding effect is based on the introduction of Zn(OTF)2and Zn(ClO4)2to 2 mol/L ZnSO4electrolytes. Simulations and experiments indicate that the Zn(OTF)2and Zn(ClO4)2not only create a molecularly crowded electrolyte environment to promote the interaction of Zn2+and OTF−, but also participate in the reduction to construct a robust and high ionic-conductive SEI, thus promoting metal zinc deposition to the (002) crystal surface. With this molecular crowding electrolyte, a high current density of 1 mA/cm2can be obtained by assembling symmetric batteries with Zn as the anode for over 1000 h. And in a temperature environment of −10 °C, a current density of 1 mA/cm2can be obtained by assembling symmetric batteries with Zn for over 200 h. Zn//Bi2S3/VS4@C cells achieve a CE rate of up to 99.81% over 1000 cycles. Hence, the utilization of a molecular crowding electrolyte is deemed a highly effective approach to fabricating a sophisticated SEI for a zinc anode.

A versatile microporous metal–organic framework (MOF), {[Cu(TIA)]·1.5CH3OH}n(Cu-1), was successfully obtained via the solvothermal reaction of cuprous(II) salt with the bifunctional ligand 3-(1H-1,2,4-triazol-1-yl)isophthalic acid. Single-crystal X-ray diffraction studies indicate that Cu-1contains an apothree-dimensional skeleton and two types of one-dimensional channels. The framework of Cu-1has excellent acid-alkali resistance and thermal stability, which is stable in a pH = 2–13 aqueous solution and an 260 °C air environment. In addition, the microporous copper MOF shows very high uptakes of CO2(180 cm3·g–1) and C2H2(113 cm3·g–1) at 273 K and displays excellent adsorption selectivity for small molecular gases. The ideal adsorbed solution theory selectivity values for C2H2/C2H4, CO2/CH4, and CO2/N2are 2, 9, and 22 at 298 K, respectively. At the same time, breakthrough experiments for CO2/CH4, CO2/N2, and C2H2/C2H4were further conducted to verify the efficient separation performances.

A porous cationic Ag(I) coordination polymer, [Ag(1,2,4,5-p4b)](SbF6) (TJNU-302) with the ligand 1,2,4,5-p4b (1,2,4,5-tetra(pyridin-4-yl)benzene), is reported that shows high sorption capacity (211 mg g–1) and distribution coefficient Kd(5.8 × 105mL g–1) as well as outstanding selectivity in 500 times excess of CO32–or PO43–anion for perrhenate removal. TJNU-302 can act as a crystalline turn-off sensor for perrhenate upon UV radiation. In this way, a test paper strip for sensing ReO4–could be produced. In water solution, TJNU-302 shows an efficient fluorescence quenching response to ReO4–ion, with the highest quenching percentage (86%) among all reported ReO4–sensors. These results could be elucidated by the bonding properties of single-crystal structures of TJNU-302 before and after perrhenate sorption, as well as density functional theory (DFT) calculations.

As the extension of the linear inverted pendulum &#x0028 LIP &#x0029 and planar inverted pendulum &#x0028 PIP &#x0029 , this paper proposes a novel spatial inverted pendulum &#x0028 SIP &#x0029 . The SIP is the most general inverted pendulum &#x0028 IP &#x0029 than any existing IP. The model of the SIP is presented for the first time. The SIP inherits all the characteristics of the LIP and the PIP, which is a nonlinear, unstable and underactuated system. The SIP has five degrees of motion freedom and three control forces. Thus, it is a multiple-input and multiple-output &#x0028 MIMO &#x0029 system with nonlinear dynamics. To realize the spatial trajectory tracking of the SIP, the control structure with five PID controllers will be designed. The parameter tuning of the multiple PIDs is a challenging work for the proposed SIP model. To alleviate the difficulties of the parameter tuning for the multiple PID controllers, optimal PIDs can be achieved with the help of Big Bang-Big Crunch &#x0028 BBBC &#x0029 optimization. The BBBC algorithm can successfully optimize the parameters of the multiple PID controllers with high convergence speed. The optimization performance index of the BBBC algorithm is compared with that of the particle swarm optimization &#x0028 PSO &#x0029 . Simulation results certify the rightness and effectiveness of the proposed control and optimization methods.

A methodology was developed to design superior sorbents of oxoanions. To integrate the high efficiency of chemisorption, selectivity, and recyclability into one sorbent, understanding the nature of oxoanions–sorbent interactions and the structural evolution of the sorbents is essential. Three cationic Ag(I) coordination polymers (CPs) are synthesized for dichromate (Cr2O72–) removal, and three distinct oxoanion-exchange mechanisms are identified, namely, the replacement, breath, and reconstructionprocesses, depending on the degree of framework distortion induced by the dichromate–CP interactions. The single crystal to single crystal transformation during the oxoanion exchange has been investigated by using single-crystal X-ray diffraction and energy-dispersive X-ray microanalysis. The replacement process, due to a weak chemisorption, shows excellent recyclability at the cost of reduction of efficiency and selectivity of adsorption. The reconstruction process may achieve a high efficiency and selectivity, but it loses recyclability. Due to the formation of a Ag–O(dichromate) bond and the breathing effect of the framework, the sorbent with the breath mechanism shows both superior efficiency and high recyclability in dichromate removal. The study of perrhenate (ReO4–) removal using the same CPs demonstrates that one CP performing the reconstruction process during dichromate removal turns to the breath process in removal of perrhenate anions. These results of mechanism–property correlation provide an insight into improvement of the methodology to fabricate a superior CP sorbent for oxoanion removal.

The synergetic effect of a reactive compatibilizer and organo-montmorillonite (OMMT) on phase morphology and properties of polyamide 6 (PA6)/polydimethylsilicone (PDMS) blend with a high viscosity ratio of dispersed phase and matrix was studied. A small amount of an amine-terminated copolymer of polyether amine (PEA) and PDMS (PDMS-b-PEA) as a reactive compatibilizer can significantly decrease the dispersed phase domain size. However, the dispersed phase domain size has still been above 2 μm even when the PDMS-b-PEA concentration reaches 5 wt %. OMMT as the second additive can further dramatically decrease the dispersed phase domain size due to the barrier effect for effectively preventing the coalescence of the dispersed phase domain. Moreover, the presence of PDMS-b-PEA can promote the uniform dispersion of OMMT. The synergetic effect of PDMS-b-PEA and OMMT can also improve tensile properties and decrease water absorption.

To alleviate the undesirable vibration and acoustic noise of switched reluctance motor (SRM), an asymmetric-carrier random PWM (ACRPWM) method is designed to shape the harmonic spectra for the speed control of the SRM. The ACRPWM can not only effectively spread the harmonic spectra of the voltage to a more wide frequency range, but also maintain the fixed switching frequency in the control of the converter. The shaping of the harmonic spectra can reduce the harmonic components beside the switching frequency and its integer multiples. The harmonic spread factor and total harmonic distortion are used to evaluate the performance of the ACRPWM. The ACRPWM is tested on hard and soft switching modes of the converter in the speed control of the SRM, respectively. Simulation results certify the effectiveness of the proposed ACRPWM in the shaping of the harmonic spectra for the SRM.

An electride molecule e–···K(1)+···calix[4]pyrrole···K(2)+···e–as an external electric field (F) manipulated nonlinear optical (NLO) switch is designed theoretically for the first time. As this molecule is an unusual singlet diradical electride molecule with two easily driven excess electrons (by electric field) at two opposite ends of the molecule, a novel switching mechanism of electronic structure isomerization emerges as a distinctive nonbonding evolution in the electride molecule. A small electric field driving leads to a long-range excess electron transfer from one side K(1) through the middle calix[4]pyrrole to the other side K(2), forms a lone excess electron pair of s-type rather than a single bond, and quenches the singlet diradical. Meanwhile, the molecular electronic structure becomes K(1)+···calix[4]pyrrole···K(2)+···2e–. Therefore, the small electric field driving brings a very high static first hyperpolarizability (β0) contrast from 0 (F= 0, Off form) to 4.060 × 105au (F= a small nonzero value of 5 × 10–4au, On form). Notably, under the electric field of 30 × 10–4au, β0reaches the largest value of 3.147 × 106au and the molecule displays the most optimal NLO switching behavior. Furthermore, we consider also that 4H atoms of calix[4]pyrrole are substituted with 4F and 2Be atoms, respectively; then the 2Be and 4F substitution effects on the NLO switch in electride molecules are exhibited. This work opens a new research field of an electric field manipulated NLO switch of electride molecules.

Outlier detection is an important task in multivariate calibration because the quality of a calibration model is determined by that of the calibration data. An outlier detection method was proposed for near infrared (NIR) spectral analysis. The method was based on the definition of outlier and the principle of partial least squares (PLS) regression, i.e., an outlier in a dataset behaved differently from the rest, and the prediction result of a PLS model was an accumulation of several independent latent variables. Therefore, the proposed method built a PLS model with a calibration dataset, and then the contribution of each latent variable was investigated. Outliers were detected by comparing these contributions. An NIR spectral dataset of orange juice samples was adopted for testing the method. Six outliers were detected in the calibration set. The root mean squared error of cross validation (RMSECV) was reduced from 16.870 to 4.809 and the root mean squared error of prediction (RMSEP) was reduced from 3.688 to 3.332 after the removal of the outliers. Compared with a robust regression method, the result of the proposed method seemed more reasonable.

Mould infection is a significant postharvest issue for processors of tobacco, which can cause direct product loss and value reduction of product as well as serious economic losses. However, mould mostly is undetectable at the early stages using traditional sorting techniques. In this study, near infrared (NIR) spectroscopy was used to detect mould infection in flue-cured tobacco samples. Based on visual analysis grading a good to bad (GBA) algorithm for feature selection of NIR spectra and linear discriminant analysis routines were applied to detect mould contamination. The optimal wavelengths of NIR spectra included bands at 1066 nm, 1130 nm, 1832 nm and 1474 nm which were applied to establish a classification model which achieved a low classification error rate (2.92% with a Wilks's λ of 0.216 at P< 0.001). The classification accuracies of unmould and mould were 94.6% and 96.9%, respectively (100.0% for slight mould, 100.0% for low mould, 95.0% for medium mould and 92.9% for high mould). A sorting system was developed based on multispectral NIR bands. This showed rapid, accurate and effective detection, and identification of mould-contaminated tobacco was possible at early stages of mould contamination, making it possible to remove mould-contaminated tobacco found in tobacco lots.

Mould infection is a significant postharvest issue for processors of tobacco, which can cause direct product loss and value reduction of product as well as serious economic losses. However, mould mostly is undetectable at the early stages using traditional sorting techniques. In this study, near infrared (NIR) spectroscopy was used to detect mould infection in flue-cured tobacco samples. Based on visual analysis grading a good to bad (GBA) algorithm for feature selection of NIR spectra and linear discriminant analysis routines were applied to detect mould contamination. The optimal wavelengths of NIR spectra included bands at 1066 nm, 1130 nm, 1832 nm and 1474 nm which were applied to establish a classification model which achieved a low classification error rate (2.92% with a Wilks's λ of 0.216 at P < 0.001). The classification accuracies of unmould and mould were 94.6% and 96.9%, respectively (100.0% for slight mould, 100.0% for low mould, 95.0% for medium mould and 92.9% for high mould). A sorting system was developed based on multispectral NIR bands. This showed rapid, accurate and effective detection, and identification of mould-contaminated tobacco was possible at early stages of mould contamination, making it possible to remove mould-contaminated tobacco found in tobacco lots.

Using the M06-2X density functional theory, unusual manipulative effects of spin multiplicity and excess electron number on the structure and static first hyperpolarizability (β0) are revealed for new electride molecules with multiexcess electrons. (1) For the spin effect on molecular structure, the low spin multiplicity brings bent structures (1L2and 2L3) for linear isomers. (2) For the dramatic effect of spin multiplicity on β0, the considerable β0of 22.7 × 104au for the low spin structure 2L3is larger by 21 times than that of 1.1 × 104au for the high spin structure 4L3due to one excess electron spin reversal. The low spin structure with doubly and singly occupied frontier orbitals is relevant to the low transition energy and complex distribution of electron density, which dramatically enhances β0. (3) For the effect of excess electron number on β0, the β0value increases rapidly with increasing excess electron number. A long chain-shaped electride molecule (for instance, 2L3) with multiexcess electrons in low spin state may bring a considerable static first hyperpolarizability, which is a novel manipulation strategy of enhancing molecular NLO response.

Because the anisotropy of shale formation should result in that wellbore deviations is unpredictable, the bit-rock interaction should be fully lucubrated in order to eliminate this problem. The impact of shale rock anisotropy and the cutting velocity on the load of PDC cutter wasn’t considered by the existing cutter-rock interaction models. On the basis of experiments of cutting shale with PDC cutter, using the stress tensor analysis theory, the relationship between the shale rock anisotropy and the cutter’s force is proposed in this paper. A new cutter-rock interaction model was established, and then a new bit-rock interaction model was set up. That applying these models to the ROP prediction of directional PDC bit can improve forecast accuracy is found.

Quasi-homogeneous lean mixture combustion technology can take full advantages of lean-combustion, and help reduce the engine fuel consumption and emissions. Quasi-Homogeneous Lean-burn engine Control System, combined virtual instruments with engine electronic control technology, can precisely control air-fuel ratio injection, timing, fuel injection pulse and ignite on timing, which provides a reliable and convenient platform for the engine lean-burning performance tests..

A novel biodegradable and biocompatible composite of Poly (propylene carbonate) (PPC) and graphenes oxide (GO) was prepared by a solution blending method. The chemical structure, thermal properties and microscopic morphologies of the GO/PPC composites were characterized by Fourier transform infrared spectroscopy (FT-IR), thermo gravimetric analysis  (TGA) and scanning electron microscopy (SEM). It was shown that the GO/PPC composites with 0.75 wt% GO performed a significant improvement on mechanical properties and thermal properties, as compared with the neat PPC. This composite could become a promising alternative to non-biodegradable for food packaging materials.

Through confined compression test and direct shear test, studied the mechanical properties of the same curing agent of different soil dredged mud, compared the difference of the same curing agent of different soil dredged mud. By confined compression test, the compression modulus of clay, silty sand and silty soil dredged mud after curing increases by 603.7%, 529.0% , 603.7% respectively. By direct shear test, the shear strength of clay dredged mud after curing increases to infinity; silty sands shear strength after curing increases by 209.1% in average; silty soils shear strength increases after curing by 147.5% in average. The compression and shear resistance of this kind of special curing agent for clay is best, silty sand second, but for the silty soil only has a little effect.

The Marine economy is now experiencing a rapid development, with the increase of the construction of the marine and coastal engineering and maintenance engineering for the port and waterway, the contradiction between the dumping of the dredged mud and the protection of the marine environment is becoming more and more serious. Meanwhile, in the process of the construction of the coastal engineering (the sea port), a lot of conditions are often needed for the sea reclamation. Through the curing of the dredged mud, the dredged mud will get good engineering properties and can be applied, which seems to be a good method for solving the contradiction above. The actual problems which will be solved by the experiment are whether a particular curing agent is applicable to all types of solidification of the soil, and can use DPDM software technology for analysis.

Cationic styrene-acrylate latex as surface sizing agent had been prepared with the emulsion polymerization by use of styrene, dimethylaminoethyl methacrylate, 2-ethylhexyl acrylate, modified PVA 0588 as the emulsifiers. The infrared spectrum of copolymer and particle size and physical properties were separately determined. The results indicated that the obtained copolymer emulsion was very stable, the average molecular weight of copolymer approached about 45000 and polydispersity index was 1.6. The copolymer with higher quaternization degree had smaller particle size and narrower particle distribution when initiator had the same usage. The copolymer as surface sizing agent improved the hydrophobicity of paper, the water-proofing time approached 14.7 seconds at most, the copolymer with narrow particle distribution increased 7% sizing performance than the one with wide particle distribution.

A new type of barrier composite film, imitating the structure of apple peel, was prepared in this study. Paraffins, sodium alginate, stearic acid and carboxymethyl cellulose were used to mimic the wax layer, cuticle, pectin layer and single-cell layer of the apple peel, respectively. Different factors have been considered to determine their effects on the water vapor permeability of the films, such as drying temperature, cross-linking agents and thickness of the membranes. The results showed that composite films showed good barrier property in the condition of drying temperature of 60℃ and cross-linking agents concentration of 15 mg/ml. The imitating cutinmembrane layer played an important role on resisting water vapor.

In order to improve the barrier property of the biaxially oriented polypropylene (BOPP) film, the PVA/SiO2 organic-inorganic hybrid coating on BOPP film was prepared by the sol–gel method. And the structure and properties of the hybrid composite films were characterized. The results showed that, the oxygen barrier property of the composite films was enhanced with the increase of PVA content, while the water vapor barrier property of the composite films was dropped. As the mass ratio of PVA increased to 80%, the oxygen barrier property of the composite films was 308 times that of the pure BOPP film, however, water vapor barrier character was half of the BOPP film.

The article reports on a research about the patent of 85 corporations in Qingdao. It states that the research used 85 corporations as subjects as well as analyze the composition and distribution of the patent. The research also analyzes the patent characters such as the characteristics of enterprise as the main body, transformation as the object, the advantage of enterprise driving, and the achievement from mutual promotion of inventions and patents.

A computer aided system has been developed as an aid to the preliminary selection of agitators for stirred vessels. This paper is concerned with modeling of the agitator selection process for a particular application and for general applications using the analytic hierarchy process (AHP). It is concluded that the decision-making results are fairly consistent with the human experts' decisions. The knowledge manipulation of the system has been presented from three aspects: knowledge acquisition, knowledge representation, and the methodology of handling uncertain data using the theory of fuzzy sets. The implementation of the system is illustrated by the operating procedures.

In this paper, the linear and nonlinear responses of granular composite medium consisting of spherical grains with coating shells embedded in a host medium are studied. We assume that the shell and the host medium are linear (the dielectric constants of which are and respectively), while the spherical grain is nonlinear (the dielectric constant of which is ). Starting from the definition and taking in to account the corrections to the local field within the spherical grains, expressions for the linear and high-order nonlinear susceptibilities are presented.

A recurrent formula of coupling coefficients for identical fermions with single angular momentum and isospin is given. Using the edicit coupling coefficients obtained previously and the recurrent formula here, the algorithm of CFPs can be improved.

A recurrent method for coupling coefficient calculations of five-dimensional quasispin group SO(5)tis proposed. The explicit coupling coefficients such as , and with are given.

A recurrent method for irreducible representation calculation of five-dimensional quasispin group SO(5)tis proposed. The explicit IRs in physical orthonormal basis with multiplicity up to three, such as (2tt), (2t+ t) and when are given.

A system of identical fermions with single angular momentum j and isospin is under consideration. The classification of its wave functions, the factorization and the symmetry of fractional parentage coefficients are discussed by using the generalized Wigner-Eckart theorem of semisimple compact Lie groups.

By means of a variational approach, we study the effective response of strongly nonlinear composite media with a low concentration of cylindrical or coated cylindrical inclusions. In an attempt to consider the influence of nonlinear order to effective nonlinear response, we assume that every constituent of the composites obeys a current-field relation of the form . In dilute limit, we have presented some numerical results for the case of the third-order nonlinearity (i.e. ) and the fifth-order nonlinearity (i.e. ), and compared the effective response of the third-order nonlinearity with that of the fifth-order nonlinearity, some conclusions are drawn.