The progress from intelligent interactions and supplemented/augmented reality requires artificial skins to shift from the single‐functional tactile paradigm. Dual‐responsive sensors that can both detect pre‐contact proximal events and tactile pressure levels enrich the perception dimensions and deliver additional cognitive information. Previous dual‐responsive sensors show very limited utilizations only in proximity perception or approaching switches. Whereas, the approaching inputs from the environment should be able to convey more valuable messages. Herein, a flexible iontronic dual‐responsive artificial skin is present. The artificial skin is sensitive to external object's applied pressure as well as its approaching, and can elicit information of target material categories encoded in the proximal inputs. Versatile applications are then demonstrated. Dual‐mode human–machine interfaces are developed based on the devices, including a manipulation of virtual game characters, navigation and zooming in of electronic maps, and scrolling through electronic documents. More importantly, the proof‐of‐concept application of an entirely touchless material classification system is demonstrated. Three types of materials (metals, polymers, and human skins) are classified and predicted accurately. These features of the artificial skin make it highly promising for next‐generation smart engineered electronics.

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Coalbed methane is a type of high-quality clean energy. The development of coalbed methane helps protect the living environment of humans and solves the safety problems in coal mining. However, a large amount of pulverized coal is generated after coalbed methane fracturing, which reduces the production of coalbed methane. Reduction of pulverized coal generation and prevention of pulverized coal migration are important for the development of coalbed methane. This study innovatively mixed calcium sulfoaluminate particles and sand to create a new fracturing proppant. The new proppant was carried by the fracturing fluid into the formation cracks and cured to form a permeable cement stone with a certain compressive strength and permeability at formation temperature and pressure. The permeability and compressive strength of the permeable cement stone were measured at different curing temperatures. Results showed that when the compressive strength of the permeable cement stone was 5.46 MPa, the gas and water permeabilities could reach 2.06 and 0.57 D, respectively. The pore diameter distribution was measured with the semi-permeable diaphragm method. The distribution curve was bimodal, and the range of the variation in pore size was 0.6–300 μm. Blocked pulverized coal size was determined using the seepage theory of particles in porous media and verified through a pulverized coal control experiment. Pulverized coal with a diameter larger than 7.67 μm was blocked by the permeable cement stone. The efficiency of the permeable cement stone in controlling pulverized coal could reach 96%. This study proved that calcium sulfoaluminate cementitious proppants can fix pulverized coal and prevent its migration. It also provided the compressive strength of propping fractures and the high permeability needed for drainage under formation conditions.

An amphoteric composite polymer (hereinafter referred to as PAADM) as a high temperature-resistant cement retarder was prepared by in situ intercalated polymerization method with 2-crylamido-2-methylpropanesulfonic acid (AMPS), acrylic acid (AA) and two diallyl dimethyl ammonium chloride (DMDAAC) as monomers, and modified montmorillonite as an active polymerization filler. The synthetic composite polymer was characterized by Fourier transform infrared spectroscopy (FT-IR), H nuclear magnetic resonance (H-NMR), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The results of the aforementioned characterization showed that the synthesized copolymer (PAADM) has an intercalation/exfoliation composite structure and excellent thermal stability. Performance evaluation evidenced that the cement slurry containing PAADM has good retarding property in the range of 120- 200C, and demonstrated the rapid development of compressive strength under high temperature and low temperature conditions, this property could guarantee that the retarder PAADM could be applied to the construction of deep wells and long interval wells. Moreover, the retarding mechanism of PAADM was studied through calcium binding capacity, adsorption amount, zeta potential, XRD and SEM analysis, and it was found that "adsorption deposition" and "calcium complexation" should be responsible for this retarder delaying the hydration process of cement grains.

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