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This research provides a design for a complaint constant-force mechanism employing a leaf-spring-like beam with variable stiffness to address the negative stiffness stroke underutilization issue of the bistable beam. By designing the compression of the leaf-spring-like beam at each given displacement and the compression ramp slope, this technique allows the constant force mechanism to potentially take full utilization of the bistable beam's negative stiffness component. Innovative design of a complaint constant force mechanism based on positive and negative stiffness is shown in this study. In addition, we conduct simulation analysis and experimental verification. The experimental results illustrate the feasibility and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

[Significance] Dolomite is a common carbonate rock and servers as an important reservoir for oil and gas. In the Sichuan Basin marine carbonate successions, for example, approximately 96% of the proved gas reserves are in dolomite reservoirs. Thus, studies of the dolomitization process, and how pores originate in dolomite, have made significant progress. However, how dolomitization affects the development of pores is still argued. [Methods] By summarizing the main theoretical viewpoints of pore origin, combined with the results of various replacement experimental simulations, this study explains the formation and evolution of pores during dolomitization and suggests lines of future research on pore origin. [Progress] The pores in dolomite are either inherited from its precursor limestone, or they have resulted from the dissolution of calcite during or after dolomitization. Dolomitization might increase, maintain or reduce reservoir porosity, depending on the environment, residence time and nature of the dolomitizing fluids. [Conclusions and Prospects] Replacement observations in experimental simulations imply that replacement is a micro-process of dissolution, migration and precipitation, accompanied by the formation of new pores that act as a channel for fluid and ion exchange to maintain the reaction. The molar volume of minerals does not influence the formation of pores. This is determined by relative solubility: that is, if the dissolution of reactants is greater than the precipitation of products, pore volume increases. The whole replacement process is accompanied by the formation of new pores, but they are mainly micropores, and their contribution to the effective porosity of a reservoir remains to be further evaluated. [ABSTRACT FROM AUTHOR]

Precise control of the manipulating force within an appropriate range is crucial to prevent potential damage to the operating object. However, achieving accurate force control through force feedback is challenging in micro-scale applications. This study presents the design of a quasi-zero stiffness-compliant constant-force microgripper with adjustable force output. The parameters of the constant-force mechanism are designed using a model-based optimization method. By utilizing this mechanism, a compliant microgripper capable of providing adjustable constant-force output is developed to overcome the limitation of traditional grippers that offer only a single constant force. Finite element analysis is performed to simulate the behavior and verify the stability of the constant-force output. Furthermore, an experimental platform is constructed to validate the mechanical properties of the developed microgripper. The experimental results demonstrate that the automatically optimized structural parameters enable the microgripper to achieve the desired constant-force value of 2 N with an adjustable range of 0.15 N. These findings provide a further basis for the application and promotion of compliant constant-force structures. [ABSTRACT FROM AUTHOR]