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In this paper, we introduce some classes of univalent harmonic functions with respect to the symmetric conjugate points by means of subordination, the analytic parts of which are reciprocal starlike (or convex) functions. Further, we discuss the geometric properties of the classes, such as the integral expression, coefficient estimation, distortion theorem, Jacobian estimation, growth estimates, and covering theorem.

In this paper, we introduce a new generalized differential operator using a new generalized quasi-Hadamard product, and certain new classes of analytic functions using subordination. We obtain certain results concerning the closure properties of the generalized quasi-Hadamard products and the generalized differential operators for this new subclasses of analytic functions with negative and missing coefficients.

In the paper, we introduce some subclasses of harmonic mapping, the analytic part of which is related to general starlike (or convex) functions with a symmetric conjecture point defined by subordination. Using the conditions satisfied by the analytic part, we obtain the integral expressions, the coefficient estimates, distortion estimates and the growth estimates of the co-analytic part g, and Jacobian estimates, the growth estimates and covering theorem of the harmonic function f. Through the above research, the geometric properties of the classes are obtained. In particular, we draw figures of extremum functions to better reflect the geometric properties of the classes. For the first time, we introduce and obtain the properties of harmonic univalent functions with respect to symmetric conjugate points. The conclusion of this paper extends the original research.

Humans possess dexterous hands that surpass those of other animals, enabling them to perform intricate, complex movements. Soft hands, known for their inherent flexibility, aim to replicate the functionality of human hands. This article provides an overview of the development processes and key directions in soft hand evolution. Starting from basic multi-finger grippers, these hands have made significant advancements in the field of robotics. By mimicking the shape, structure, and functionality of human hands, soft hands can partially replicate human-like movements, offering adaptability and operability during grasping tasks. In addition to mimicking human hand structure, advancements in flexible sensor technology enable soft hands to exhibit touch and perceptual capabilities similar to humans, enhancing their performance in complex tasks. Furthermore, integrating machine learning techniques has significantly promoted the advancement of soft hands, making it possible for them to intelligently adapt to a variety of environments and tasks. It is anticipated that these soft hands, designed to mimic human dexterity, will become a focal point in robotic hand development. They hold significant application potential for industrial flexible gripping solutions, medical rehabilitation, household services, and other domains, offering broad market prospects.

ZnO is a commonly used material for hydrogen gas sensors. In this study, a ZnO nanofiber film with a diameter of approximately 60 nm was synthesized by the electrospinning method. Compared to previously reported ZnO hydrogen gas sensors, an abnormal phenomenon was observed here, where the resistance of the ZnO nanofiber film increased upon exposure to hydrogen gas in the temperature range from 210 °C to 330 °C. The physical mechanism of this phenomenon was explored through microstructure analysis and DFT simulation calculations that showed a total charge transfer of 0.65 e for the hydrogen molecule. This study can push forward the understanding of ZnO hydrogen sensing.

Polycrystalline diamond compact (PDC) cutters are the most extensively used tool for rock drilling in superdeep oil and gas exploration, in which the air drilling technology without drilling fluid is highly promoted. This study examined the performance of PDC cutters in air drilling, including their friction angle, cutting force, specific energy, and wear behaviors, using a home-made testing apparatus and a commercial tribometer. It also investigated the dependence of cutting force on cutting depth and back rake angle. Results obtained in both dry conditions and in drilling fluid media were compared, and a tentative explanation to the observed differences was brought about by these two environments.

35CrMo steel is a widely used material in machinery equipment for the petroleum industry. With the improvement of exploring technology, some particular complex features cannot be achieved with traditional processing methods. However, electrochemical machining provides a potential solution to such problems, especially in the machining of the turbine blades of turbine drilling tools, in which the surface behavior of the workpiece is an important basis for judging the machining effect. To investigate the surface behavior of 35CrMo after electrochemical machining, the electrochemical machining experiment of 35CrMo steel was conducted by a self-made experimental system. Effects of the electrolyte type, concentration, and current density on surface quality were investigated in this study. The surface characteristics of 35CrMo steel were analyzed under different current densities in three different electrolytes—NaCl, NaClO3 and NaNO3—with different concentrations. Based on the obtained results, an optimum machining plan was obtained. The principle of the electrolysis reaction of 35CrMo steel in NaCl, NaClO3 and NaNO3 electrolytes were studied as well. Experimental results showed that the best surface quality of 35CrMo steel was achieved under an NaClO3 electrolyte concentration of 200 g/L and current density of 30 A/cm2. The results in this paper provide a theoretical basis for the effective machining of complex parts such as downhole turbine blades.

Forest biomass is an important resource for producing bioenergy and reducing greenhouse gas (GHG) emissions. The State of Michigan in the United States (U.S.) is one region recognized for its high potential of supplying forest biomass; however, the long-term availability of timber harvests and the associated harvest residues from this area has not been fully explored. In this study time trend analyses was employed for long term timber assessment and developed mathematical models for harvest residue estimation, as well as the implications of use for ethanol. The GHG savings potential of ethanol over gasoline was also modeled. The methods were applied in Michigan under scenarios of different harvest solutions, harvest types, transportation distances, conversion technologies, and higher heating values over a 50-year period. Our results indicate that the study region has the potential to supply 0.75–1.4 Megatonnes (Mt) dry timber annually and less than 0.05 Mt of dry residue produced from these harvests. This amount of forest biomass could generate 0.15–1.01 Mt of ethanol, which contains 0.68–17.32 GJ of energy. The substitution of ethanol for gasoline as transportation fuel has potential to reduce emissions by 0.043–1.09 Mt CO2eq annually. The developed method is generalizable in other similar regions of different countries for bioenergy related analyses.