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Electrochemical measurements at the single entity level provide ultra-sensitive tools for the precise diagnosis and understanding of basic biological and chemical processes. By decoding current signatures, single-entity electrochemistry provides abundant information on charges, sizes, shapes, catalytic performances and compositions. The accuracy of single-entity electrochemistry highly relies on advanced instrumentation to achieve the amperometric resolution at the sub-picoampere level and the temporal resolution at the sub-microsecond level. Currently, it is still a challenge for paralleling amplifiers to allow low-noise and high bandwidth single-entity electrochemical measurements. Herein, we developed a low-noise four-channel electrochemical instrumentation that integrates an Au electrode array with amplifiers in the circuit board. With this amplifier array, we achieved a high bandwidth (>100 kHz) electrochemical measurement. The further practical experiments proved the capability of this amplifier array system in acquiring transient signals from both single-molecule detection with an aerolysin nanopore and single Pt nanoparticle catalysis during the dynamic collision process. Paired with appropriate microfluidic array systems, our instrumentation will enable an extraordinarily high-throughput feature for single-entity sensing. [ABSTRACT FROM AUTHOR]

Exploration of novel molecular switches is an ongoing hot issue in molecular electronics. Alkalides and electrides are two typical representatives of excess electron compounds. It was found that M(HF)3M (M = Li or Na) induced by an oriented external electric field are good candidates for inorganic multi-response nonlinear optical (NLO) molecular switches. Their off forms (C3h) exhibit electride-like super alkali earth atom characteristics, while their on forms (C3v) exhibit charming superalkalide (M = Na or Li) or superalkali electride characteristics (M = Li). The increases of the static first hyperpolarizabilities (β e0) from off to on forms constitute a 2–3 orders of magnitude improvement for both M = Li and Na. These extremely large differences in β e0 reinforce the potential of M(HF)3M for applications in excellent multi-response nonlinear optical materials. [ABSTRACT FROM AUTHOR]

Three isostructural pillared-layer frameworks with M-BDC-X layers supported by ditopic HL connectors, [M(HL)(BDC)0.5X]n (HL = 4′-(4-hydroxyphenyl)-4,2′:6′,4″-terpyridine, BDC = terephthalate, M = Cd, X = Cl for (1), M = Cd, X = formate for (2), and M = Co, X = formate for (3)), were solvothermally synthesized, and used as photocatalysts for Pt-assisted visible-light-initiated hydrogen evolution from water splitting. These water-durable frameworks exhibit varied hydrogen production rates of 361.2, 271.3, and 327.5 μmol · g−1 · h−1 in 12 h due to their slightly different donor environments of the octahedral CdII and CoII ions. Further experimental and theoretical investigations reveal that the metal ions and the local coordination surroundings have essentially dominated the conduction band minimum and electric resistance of the charge transport, which play highly important roles for the improved catalytic hydrogen evolution ability. These findings demonstrate the electronic effect of the slightly ligand field modifications on the boosting hydrogen generation activity in the noble metal-assisted MOF photocatalytic systems. [ABSTRACT FROM AUTHOR]

The exploration of innovative molecular switches has resulted in large developments in the field of molecular electronics. Focusing on a single molecular switch with different forms exhibiting different electride features, potassium-atom-doped all-cis 1,2,3,4,5,6-hexafluorocyclohexane K-F6C6H6 was studied theoretically. It was found that an oriented external electric field can drive excess electron transfer from the region outside of the K atom to that outside of F6C6H6. Subsequently, the electride-like molecule K-F6C6H6 (1) switches into the molecular electride K-F6C6H6⋯e− (3) through another electride-like molecule K-F6C6H6 (2). The static first hyperpolarizabilities (β0) are increased over 12- and 5-fold when moving from 1 to 2 and 3, respectively. The rise of each β0 value constitutes an order of magnitude improvement. Between them, the different β0 values suggest that K-F6C6H6 is a good candidate for use as a multiple-response nonlinear optics switch. The order of the β0 values of 1–4 for M-F6C6H6 (M = Li and Na) coincide with that of K-F6C6H6, also exhibiting a switch effect. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of constant C for ray tracing-assisted intraocular lens (IOL) power calculation in patients with different refractive power, we compared the refractive outcome of the ray tracing method based on constant C and conventional IOL calculation. Methods: 215 eyes which underwent phacoemulsification and IOL implantation were enrolled in the study. According to the average corneal power, patients were divided into 3 groups: high corneal power (K >45 D) group, medium corneal power (43 ≤ K ≤ 45 D) group, and low corneal power (K <43 D) group. The predicted sphero-equivalent refractive outcome for the IOL power implanted at surgery was calculated using the ray tracing method, SRK/T, and Haigis formulas. Results: On the basis of the corneal refractive power, there were 65 eyes of K >45 D (30.23%), 96 eyes of 43 ≤ K ≤ 45 D (44.65%), and 54 eyes of K <43 D (25.12%). In general, the ray tracing group had the smallest value of mean absolute error (MAE) and mean error, and the proportions of eyes with absolute error (AE) <0.50 and <0.75 D were significantly higher than those of the other 2 formulas (p = 0.010). In each group, the value of MAE was smallest in the ray tracing group; for the proportions of AEs <0.50 and <0.75 D, the values in the ray tracing group were higher than those in the SRK/T and Haigis groups. Especially in the high and low corneal refractive groups, the proportion of AE <0.25 D was also obviously higher, but only in the low corneal refractive power group, and the difference was statistically significant (p = 0.006). Conclusions: Compared with the conventional formulas, C constant of the ray tracing-assisted IOL power calculation has more accuracy for the patients with different corneal refractive powers. Ray tracing could provide better guidance for IOL selection clinically. [ABSTRACT FROM AUTHOR]

Examines the surface relief accompanying martensite and bainite in a copper-zinc-aluminum alloy using atomic force microscopy (AFM). Comparison between the transformation mechanism of bainite and martensite; Information on the surface relief effect; Principles of AFM; Description of the three clusters of relief.

Two new coordination polymers, namely [Zn2(phen)2(DHTA)]·2H2O (1) and [Zn2(PHDI)2(DHTA)]·2H2O (2) (phen = 1,10-Phenanthroline, PHDI = 1,10-Phenanthroline-5,6- dione, DHTA = 2,5-dihydroxyterephthalic acid) have been synthesized under hydrothermal conditions. The structures have been determined by single crystal X-ray diffraction, thermal gravimetric analysis, infrared spectrum and luminescent properties. The X-ray diffraction analysis revealed the coordination modes of Zn(II) centers from complexes (1) and (2) are different. In (1), there are unusual five coordinated and six coordinated Zn(II) ions. In (2), the center is four coordinated Zn (II). Through these coordination modes of Zn centers and the π-π stacking interactions of organic ligands, the two complexes are all connected to three-dimensional supramolecular networks. The solid-state photoluminescence properties of (1) and (2) have been investigated. The emission peaks are located at 538 and 603 nm, the emissions may be attributed to the metal-to-ligand charge-transfer. The quantum-chemical calculations have been performed on ‘molecular fragments’ extracted from the crystal structure using the B3LYP method in Gaussian 09. [ABSTRACT FROM AUTHOR]

The control of the X-Z inverted pendulum is a challenging work since the X-Z inverted pendulum is an underactuated, open-loop unstable and multi-input-multi-output (MIMO) nonlinear system. In this paper, we will present a novel state transformation method for the X-Z inverted pendulum and Big Bang–Big Crunch (BBBC) optimized hierarchical sliding-mode control (HSMC) structure. We will firstly show that through the proposed transformation, the model of the X-Z inverted pendulum can be transformed to a typical underactuated form. Thus, based on the obtained system model, the hierarchical sliding-mode control (HSMC) can be directly applied in the trajectory tracking control of the X-Z inverted pendulum. Then, to ensure a convergent performance of the auxiliary sliding surfaces, the BBBC method is applied to obtain the optimal coupling factors for the HSMC. The control performance of the proposed BBBC based HSMC structure is compared with that of the present SMC and the HSMC with particle swarm optimization (PSO). Simulation results show the effectiveness of the proposed controllers for the X-Z inverted pendulum. [ABSTRACT FROM AUTHOR]

Abstract: In novel superatom chemistry, it is very attractive that all‐metal clusters can mimic the behaviors of nonmetal atoms and simple nonmetal molecules. Wizardly all‐metal halogen‐like superatom Al13 with 2P5 sub shell (corresponding to the 3p5 of chlorine) is the most typical example. In contrast, how to mimic the behaviors of magnetic transition‐metal atom using all‐nonmetal cluster is an intriguing challenge for superatom chemistry. In response to this based on human intuition, using quantum chemistry methods and extending jellium model from metal cluster to all‐nonmetal cluster, we have found out that all‐nonmetal octahedral B6 cluster with characteristic jellium electron configuration 1S21P62S21D8 in the triplet ground state can mimic the behaviors of transition‐metal Ni atom with electron configuration 3s23p64s23d8 in electronic configuration, physics and chemistry. Interestingly, the characteristic order of 1S1P2S1D for the B6 nonmetal cluster with short B‐B lengths is different from that of the traditional jellium model—1S1P1D2S for metal clusters with long M‐M lengths, which exhibits a novel size effect of nonmetal cluster on jellium orbital ordering. Based on the jellium electron configuration, the B6 with the spin moment value of 2μB is a new all‐nonmetal transition‐metal nickel‐like superatom exhibiting a new kind of all‐nonmetal magnetic superatom. Finding the application of the all‐nonmetal magnetic superatom, we encapsulate the magnetic superatom B6 inside fully hydrogenated fullerene forming a clathrate B6@C60H60 with the spin moment value of 2μB. As the C60H60 cage as a polymerization unit can conserve the spin moment of endohedral B6, the clathrate B6@C60H60 is a new all‐nonmetal magnetic superatom building block. Naturally, magnetic superatom structures of the B6 and B6@C60H60 may be metastable. [ABSTRACT FROM AUTHOR]

Because of the double–salient structure and switching mode of switched reluctance motor (SRM), it is very difficult to acquire the analytical model for the SRM. The current-sharing method (CSM) is an effective inner-current loop designing strategy, which makes the high performance control of the SRM become possible without application of its mathematical model. However, there are six control parameters that need to be tuned in the CSM. If the PID controller is adopted in the speed loop, there will exist nine parameters that need to be tuned in the speed control of the SRM. It is a challenge work to tune nine parameters with manual trial-and-error method. To alleviate the difficulties of the parameter tuning for the SRM control, three types of evolutionary computation methods are applied in the parameter optimization of the SRM, which include differential evolution (DE) algorithm, Big Bang–Big Crunch (BBBC) algorithm and particle swarm optimization (PSO). The comparison of the optimization performance among the proposed evolutionary computation methods are demonstrated with Matlab simulation. Simulation results certify the feasibility and effectiveness of the proposed methods in the parameter optimization and speed control of the SRM. [ABSTRACT FROM AUTHOR]