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Soft actuators have been an important research focus in robotics due to their advantages in nondestructive contact and excellent motion adaptability, which enable flexible manipulation, extreme environments exploration, and in vivo surgical treatment. Various soft robots actuated electrically, magnetically, optically, and fluidically are built toward different application scenarios. Among them, electrical actuation method is an advanced choice to actuate and control soft actuators that are expected to be compatible and integrated with existing industrial robotic systems and wearable intelligent devices. Current robotic systems have higher requirements on the actuators' function, which can be explored through material and structural designs. Based on a variety of deformable materials, the structural design enables the soft actuators to span from low dimension to high dimension with further improvement in function. Therefore, in this review, 2D and 3D electrical‐based soft actuators from the perspective of dimension design are introduced, which involve functional materials, structure design, and fabrication technology. Some novel 3D fabrication methods, such as the 3D compressive buckling process, are summarized to build 3D soft robots. This review aims at offering important guidelines for the development of soft actuators and the construction of integrated robotic systems in the future. [ABSTRACT FROM AUTHOR]

In this paper, the effect of pre-injection timing on the combustion and emission performance of methanol/diesel high premixed charge compression ignition (HPCCI) combustion mode at low load was studied by three-dimensional numerical simulation. The simulation is carried out under the conditions of 1900 r/min and 25% load, and the pre-injection diesel mass remains constant and the pre-injection timing is changed under the conditions of 50% and 60% methanol ratio respectively. The results show that with the delay of pre-injection timing, the evaporation of pre-injected fuel in cylinder becomes faster, the low temperature reaction is enhanced, and the peak value of heat release rate is higher. In addition, the distribution of pre-injected diesel in cylinder and the position of impact wall are the important factors affecting the combustion and emission performance in cylinder, and when the injection timing is -35 °CA ATDC, the combustion and emission characteristics of the engine are optimal. Finally, by comparing with the traditional RCCI combustion mode, the enhancement ability of HPCCI combustion mode on methanol combustion efficiency under low load is verified and analyzed.

The effects of methanol/polyoxymethylene dimethyl ethers (PODE) mixture with different blending ratios on premixed charge compression ignition (PCCI) combustion and emission performance have been researched through the anlysis of CFD software CONVERGE. Premixed combustion is achieved by a single early injection of fuel into the cylinder. The results show that the combustion start point delays and the peak pressure decreases with the increase of methanol blend ratio. The effects of injection timing on the combustion and emission characteristics of PCCI were studied by using a mixture of the same proportion of methanol. The results show that the advance of injection time leads to more homogeneous mixture and higher peak heat release. But too early injection reduces the temperature in the cylinder and makes the combustion worse, resulting in the increase of HC, soot and CO emissions. NOx emissions decrease with the advance of the injection time.

A 3d–4f heterometallic compound, namely [Ni6GdL4(ox)(H2O)12]⋅[NO3]⋅14.5H2O (1) (L=2,2'‐phosphinico‐dibenzoate and ox=oxalate), was obtained by self‐assembly of nickel nitrate, gadolinium nitrate, oxalic acid, and 2,2'‐phosphinico‐dibenzoic acid (H3L). Such compound has been structurally characterized via single‐crystal X‐ray diffraction analysis and infrared spectroscopy. This compound features a basic unit of {Ni4Gd} clusters and 2,2'‐phosphinico‐dibenzoate ligands. Each unit is connected by another Ni2+ through the axial coordination of benzoate oxygen to form a layer. Meanwhile, each oxalate ligand bridges the expanded Ni4Gd‐Ni4 net, constructing a 3‐D framework. From the viewpoint of network topology, this compound can be simplified as a sqc6 topology. Magnetic analysis shows ferromagnetic interactions between the Ni(II) and Gd(III) centers in Ni4Gd nodes and antiferromagnetic coupling with oxalate bridges in this compound. [ABSTRACT FROM AUTHOR]

A method for technical evaluation of sealing agent used for rapid roll-to-roll gold electroplating in laboratory were established from the following aspects: properties of gold coating, efficiency of sealing, cost of sealing agent, and environmental friendliness. The test methods were described. The comprehensive performance of three sealing agents were quantitatively evaluated, providing a reference for plating plants to select excellent sealing agent for gold coatings. [ABSTRACT FROM AUTHOR]

In order to improve the cuttings transport ability and well hole purification effect of horizontal shale gas wells in the Sichuan and Chongqing area, a new type of aluminum alloy drill pipe is put forward, and the floatability is validated by theoretical analysis and actual parameter calculation. According to the cuttings migration mechanism, the cuttings cleaning simulation model of the new aluminum alloy drill pipe and the traditional steel drill pipe was established by Fluent, and the hexahedral mesh is used to divide the model. Thus, the mesh independence and convergence of the two models are verified. Then, the simulation model is verified by comparing the calculation results of the two simulation models with the experimental data of the indoor cuttings migration device. Finally, the rock-cleaning ability of the two drill pipes is analyzed under the conditions of changing the cuttings particle size, well inclination angle, displacement, and mechanical speed. Compared with the traditional steel drill pipe, the new aluminum alloy drill pipe can improve the borehole purification capacity by 13% on average. This research result is of great significance in reducing the quality of cuttings in the annulus and improving the borehole purification effect. [ABSTRACT FROM AUTHOR]

In this paper, we are interested in the study of approximate optimality conditions for weakly ϵ-efficient solutions to robust multi-objective optimization problems ((RMOP) for short) in view of its associated minimax optimization problem (MMOP). To this end, we first establish the relationship between a weakly ϵ-efficient solution to the problem (RMOP) and an α-solution to the problem (MMOP), where ϵ = (ϵ 1 , ... , ϵ p) ∈ R + p ∖ { 0 } and α = max j = 1 , ... , p { ϵ j }. Then, we explore the representation of the so-called β-normal set (where β ≥ 0 is a given parameter) to a closed convex set at some reference point by two methods. At last, by employing the α-subdifferential of the max-function and the obtained representation of the β-normal set, we establish an approximate necessary optimality condition for the problem (RMOP). Moreover, we also give an example to illustrate our results. [ABSTRACT FROM AUTHOR]