Abstract: The present disclosure provides a risk assessment method of water inrush in tunnels constructed in water-rich grounds. The method includes the following steps: simulating a tunnel excavation process by finite element software MIDAS GTS NX and fluid-structure interaction; according to a research method of control variables, analyzing effects of a groundwater level, an elastic modulus and advanced pipe shed grouting on the stability of surrounding rock, and improving an algorithm of a radial basis function (RBF) neural network using a Grey Relation Analysis (GRA)-based Partitioning Around Medoid (PAM) clustering algorithm to assess risks of water inrush occurring in Qingdao area.

Abstract: The present disclosure provides a multi-factor quantitative analysis method for deformation of a neighborhood tunnel. The method includes the following steps: analyzing monitoring data generated at a tunnel site; simulating collapse occurring at a shallow buried section of a tunnel; determining the degree of influence of each factor on the tunnel and a stratum; and determining quantitative influence of each factor on tunnel deformation. The present disclosure can not only provide an accurate theoretical basis for the construction of the shallow buried section of the small-distance tunnel, but also guarantee safety and cost saving during tunnel construction.

Abstract: A bit may include a matrix portion, the matrix portion exposed at a cone region and a nose region of the bit. A bit may include a steel portion, the steel portion including a bit connection, the steel portion exposed at a gauge region of the bit. A bit may include a plurality of cutting elements secured to the matrix portion at the cone region and the nose region.

Abstract: The disclosure relates to a chemical ablation apparatus for treating arrhythmia, comprising: a clamp body, a clamp head consisting of a pair of clamp jaws, a needle head assembly, a needle head extension and retraction control assembly, pipeline components, and an electrocardiographic mapping component. The chemical ablation apparatus can control needle heads to extend out of or retract into the clamp head by means of the needle head extension and retraction control assembly. A chemical ablation reagent may be injected to a cardiac muscle tissue to conveniently achieve complete ablation of the cardiac muscle tissue by applying a chemical ablation method. The ablation effect can be verified by the electrocardiographic mapping system, to thereby increase the success rate and lower the difficulty level of arrhythmia ablation operations, while also reducing the manufacturing cost of the ablation apparatus and corollary equipment thereof, and decreasing the expenses for atrial fibrillation surgical operations.

Abstract: An oceaneering test platform device for simulating oceaneering working conditions is disclosed. The oceaneering test platform device comprises a main body, a lifting unit, a plurality of spud legs connected to the main body by the lifting unit, a plurality of base units located correspondingly to the plurality of spud legs and one or more vertical driving unit to enable vertical movement of at least one of the plurality of spud legs. The test platform device facilitates simulation of possible effects caused by unstable and complex ocean environments to an offshore work platform.

Abstract: The invention relates to a preparation method of graphene using graphene oxide. The method consists of the following steps. (1). Preparation of graphene oxide-dispersant solution; (2). Reduction of graphene oxide; (3). Obtaining graphene by suction filtration and drying process. Based on the preparation of anthracite, the invention could reduce production costs effectively comparing to traditional preparation methods of graphene, and make the reaction more fast and complete, facilitating the achievement of large scale industrial production.

Abstract: The present invention provides a preparation method for graphene quantum dots with different oxygen contents, including the following steps: Step 1: dispersing a graphene oxide in a peroxide solution to obtain a graphene oxide dispersion; Step 2: mixing the graphene oxide dispersion with an alkali liquor, purifying to obtain a graphene quantum dot dry powder; Step 3: loading the graphene quantum dots dry powder on a carrier, performing a gradient elution to obtain a plurality of graphene quantum dots with different oxygen contents. The preparation method for graphene quantum dots can realize the control of oxygen content of the graphene quantum dots. Therefore, the control of the emission wavelength of the product is achieved, which provides a reliable premise for applications of the graphene quantum dots in the fields of LED, cell labeling, etc. In addition, the method provided by the present invention is also simple and easy to operate.

Abstract: An oceaneering test platform device for simulating oceaneering working conditions is disclosed. The oceaneering test platform device comprises a main body, a lifting unit, a plurality of spud legs connected to the main body by the lifting unit, a plurality of base units located correspondingly to the plurality of spud legs and one or more vertical driving unit to enable vertical movement of at least one of the plurality of spud legs. The test platform device facilitates simulation of possible effects caused by unstable and complex ocean environments to an offshore work platform.

Abstract: The present invention relates to a preparation method of graphene oxide based on anthracite. The method consists of the following steps. a. Preparation of ultra-clean anthracite powder; b. Pretreatment of ultra-clean anthracite powder; c. Preparation of anthracite oxide dispersion; d. Preparation of graphene oxide colloid solution; e. Preparation of graphene oxide. The invention also relates to a preparation method of graphene using graphene oxide obtained by method mentioned before. The method consists of the following steps. f. Preparation of graphene oxide-dispersant solution; g. Reduction of graphene oxide; h. Obtaining graphene by suction filtration and drying process. Based on the preparation of anthracite, the invention could reduce production costs effectively comparing to traditional preparation methods of graphene and graphene oxide, and make the reaction more fast and complete, facilitating the achievement of large scale industrial production.

Abstract: The invention relates to a preparation method of graphene using graphene oxide. The method consists of the following steps. (1). Preparation of graphene oxide-dispersant solution; (2). Reduction of graphene oxide; (3). Obtaining graphene by suction filtration and drying process. Based on the preparation of anthracite, the invention could reduce production costs effectively comparing to traditional preparation methods of graphene, and make the reaction more fast and complete, facilitating the achievement of large scale industrial production.

Abstract: A solid phase extraction column, preparation method therefor, and pre-processing method of chemical sample based on solid phase extraction column. The solid phase extraction column includes a separation column, and a solid phase extraction agent tilled within the separation column. The solid phase extraction agent is graphene or modified graphene. The solid phase extraction column is prepared by loading the solid phase extraction agent into the separation column, and vibrating to compact the solid phase extraction agent. The solid phase extraction column is used to pre-process a chemical sample to realize a highly effective separation effect. The problem of data distortion caused by being unable for a target component to be detected in a subsequent detection or being unable to detect a real value, is avoided.

Abstract: A method for preparing graphene quantum dots in large-scale, comprising: dispersing graphene oxide uniformly in the first solvent to obtain a first dispersion liquid, adding reducing agent into the first dispersion liquid and dispersing uniformly to give a mixed solution; treating the mixed solution for 10˜60 mins under microwave environment with the power being at 500˜800 W, then cooling and separating to obtain the solid as a crude product; mixing, one of the reducing polyhydroxy aldehyde or organic acid with the crude product, following by adding the Lewis acid to obtain a mixture, dispersing the mixture in a second solvent uniformly to obtain a second dispersion liquid; putting wherein the second dispersion liquid into microwave treatment for 0.2-1 hours with the microwave power being 500˜800 w, then stripping for 2˜3 hours under ultrasonic power of 120˜300 w, purifying to obtain the graphene quantum dots.

Abstract: A method for repairing a reduced graphene oxide, the method comprising the following steps: Dispersing the reduced graphene oxide into a solvent to obtain a graphene dispersion liquid, adding a first Lewis acid and a compound containing a methyl or methylene group to obtain the first mixture, reacting the first mixture in a microwave environment of which power is 300˜900 w for 0.5˜2 hours, refluxing for 3˜5 hours; separating, purifying and drying to obtain the first crude product; adding the first crude product into a second Lewis acid, adding an aromatic hydrocarbon repairing agent to obtain the second mixture, reacting the second mixture to obtain a molten solid, separating and purifying same to obtain the second crude product; mixing the second crude product, a metal powder catalyst and a third Lewis acid to obtain the third mixture, this method can repair reduced graphene oxide effectively.

Abstract: The present invention relates to a preparation method of graphene oxide based on mixed acid system. The method consists of the following steps. a. Preparation of graphite powder; b. Preparation of suspension liquid of first acid system; c. Preparation of second acid system; d. Preparation of graphene oxide. The invention also relates to a preparation method of graphene using graphene oxide obtained by method mentioned above. The method consists of the following steps. e. Preparation of graphene oxide-dispersant solution; f. Reduction of graphene oxide; g. Process of supersonic stripping; h. Obtaining graphene by separation and drying. The preparation methods of graphene oxide and graphene in our invention could reduce the dosage of strong acid as well as heat release of chemical reaction, and cause less corrosion to our equipments, which makes the reaction more effective and properties of graphene products better, facilitating the achievement of large scale industrial production.

Abstract: The present invention relates to a preparation method of graphene oxide based on anthracite. The method consists of the following steps. a. Preparation of ultra-clean anthracite powder; b. Pretreatment of ultra-clean anthracite powder; c. Preparation of anthracite oxide dispersion; d. Preparation of graphene oxide colloid solution; e. Preparation of graphene oxide. The invention also relates to a preparation method of graphene using graphene oxide obtained by method mentioned before. The method consists of the following steps. f. Preparation of graphene oxide-dispersant solution; g. Reduction of graphene oxide; h. Obtaining graphene by suction filtration and drying process.

Abstract: A method for repairing a reduced graphene oxide, the method comprising the following steps: Dispersing the reduced graphene oxide into a solvent to obtain graphene dispersion liquid, adding a first Lewis acid and a compound containing a methyl or methylene group to obtain the first mixture, reacting the first mixture in a microwave environment of which power is 300˜900 w for 0.5˜2 hours, refluxing for 3˜5 hours; separating, purifying and drying to obtain the first crude product; adding the first crude product into a second Lewis acid, adding an aromatic hydrocarbon repairing agent to obtain the second mixture, reacting the second mixture to obtain a molten solid, separating and purifying same to obtain the second crude product; mixing the second crude product, a metal powder catalyst and a third Lewis acid to obtain the third mixture, this method can repair reduced graphene oxide effectively.

Abstract: A method for preparing graphene quantum dots in large-scale, comprising: dispersing graphene oxide uniformly in the first solvent to obtain a first dispersion liquid, adding reducing agent into the first dispersion liquid and dispersing uniformly to give a mixed solution; treating the mixed solution for 10˜60 mins under microwave environment with the power being at 500˜800 W, then cooling and separating to obtain the solid as a crude product; mixing, one of the reducing polyhydroxy aldehyde or organic acid with the crude product, following by adding the Lewis acid to obtain a mixture, dispersing the mixture in a second solvent uniformly to obtain a second dispersion liquid; putting wherein the second dispersion liquid into microwave treatment for 0.2-1 hours with the microwave power being 500˜800 w, then stripping for 2˜3 hours under ultrasonic power of 120˜300 w, purifying to obtain the graphene quantum dots.

Abstract: The present invention relates to a preparation method of graphene oxide based on mixed acid system. The method consists of the following steps. a. Preparation of graphite powder; b. Preparation of suspension liquid of first acid system; c. Preparation of second acid system; d. Preparation of graphene oxide. The invention also relates to a preparation method of graphene using graphene oxide obtained by method mentioned above. The method consists of the following steps. e. Preparation of graphene oxide-dispersant solution; f. Reduction of graphene oxide; g. Process of supersonic stripping; h. Obtaining graphene by separation and drying. The preparation methods of graphene oxide and graphene in our invention could reduce the dosage of strong acid as well as heat release of chemical reaction, and cause less corrosion to our equipments, which makes the reaction more effective and properties of graphene products better, facilitating the achievement of large scale industrial production.