Ischemic stroke is a cerebrovascular disease with high morbidity, mortality, and disability, representing serious threat to human life health. Clinically, the extensive injury caused by ischemic results from ischemia-reperfusion (I/R) thrombolytic treatment. However, there are few reports on use of medications in subacute stage cerebral I/R. Baicalein (5,6,7-trihydroxyflavone) biologically active ingredient extracted root Scutellaria baicalensis Georgi. In present study, we investigated...

Underground metal mines operated using the natural caving method often result in significant surface collapses. Key parameters such as settlement magnitude, rate, extent, and influence of underground mining on deformation warrant serious attention. However, due to long operational timespan incomplete data from early collapse events, coupled with inaccessibility zones for field measurements, it is challenging obtain accurate displacement data, thereby posing difficulties follow-up research....

Xiaoxuming decoction (XXMD), a classic traditional Chinese medicine (TCM) prescription, has been used as therapeutic in the treatment of stroke clinical practice for over 1200 years. However, pharmacological mechanisms XXMD have not yet elucidated. The purpose this study was to develop neuroprotective models identifying compounds against hypoxia-induced and H2O2-induced brain cell damage. In study, phenotype-based classification method designed by machine learning identify clarify...

Summary A high-frequency axial-torsional composite percussion drilling tool is designed to enhance the efficiency by delivering axial and torsional impact loads directly drill bit. The performance influencing factors of are analyzed via large eddy simulation method, a scaled-down experiment on pulse nozzle structure conducted. analysis reveals that after design optimization, achieves impacts 421 284 Hz, respectively, at an inlet flow rate 30 kg/s. Additionally, unilateral amplitudes reach...

In the drilling process of a horizontal well, large friction between drill string and wellbore wall can cause phenomenon backing pressure reduce efficiency. To friction, new anti-friction tool is proposed then dynamics characteristics are studied. According to actual working conditions, force analysis drill-string system conducted. The model established vibration numerical solution method used solve experimental test conducted verify structural design tool. theoretical calculation results,...

In this paper, we proposed a vertical spiral structure to realize high performance (high Q and L) on-chip inductor based on MEMS technology. It aims reduce the substrate loss by approach of 3D integration so that quality factor inductors could be improved. order verify explore improvement solenoid structure, finite element method was used analysis designed inductor, an optimal solution raised through modeling simulation commercial software HFSS. Combining thermal oxidation process level,...

Abstract In the process of long horizontal well in directional drilling, serious contact between drill string and wellbore leads to weight on bit loss. Therefore, this paper proposes a rotary controller (DSC) for well, its function test is completed through experimental platform. Connected DSC working mechanism, coupling dynamic model established under conditions drilling. case study, characteristics different units, including pipes bottom-of-hole modules axial torsional directions, are...

Aiming at the problems of large torque fluctuation drill bit and low weight-on-bit(WOB) transmission efficiency during drilling process, a novel tool generating constant reducing stick-slip is proposed. For investigating further dynamics behavior string system, mathematic models are established based on new output characteristics. Also, compared with field test application, effects increasing ROP (rate penetration) wear verified. The research results show that peak value angular velocity...

Abstract Internal motion and dynamics mechanism studies of a new composite percussion drilling tool aim at reducing stick-slip phenomenon improving rock breaking efficiency. In this study, experiments are performed using tools to investigate its torsional axial impact performance. According the experimental results, six degrees-of-freedom (6DOF) rigid body model was established study passive hammer. The obtained including tangential acceleration, were verified with data, small pressure...

The buckling behaviors of drill string may cause serious down-hole problems, such as high friction during drilling, loss weight on bit (WOB), and even failure. This paper analyzes the dynamic characteristics string, considering between wellbore. In theoretical research, key parameter expressions are determined, especially contact mathematical models proposed, which include axial displacement, angular displacement force. numerical calculation results show that influence is mainly reflected in...

Excessive stick–slip vibration of drill strings can cause inefficiency and unsafety drilling operations. To suppress the that occurred during downhole process, a string torsional system considering tool has been proposed on basis 4-degree freedom lumped-parameter model. In design model, is approximated by simple pendulum brings impact torque to bit. Furthermore, two sliding mode controllers, U1 U2, are used vibrations while enabling bit track desired angular velocity. Aiming at parameter...

Gas blowout occurred during drilling may cause catastrophic environmental hazards and economic losses. It is thus one of the important tasks to accurately determine gas volume so that an effective rescue plan can be worked out in case blowout. In this paper, a numerical method for estimating was presented based on Bernoulli Equation corresponding software programmed. process estimation, velocity distribution flame characterized by axisymmetric laminar flow investigated through analysis...

Abstract Conventional directional drilling mainly relies on the sliding of screw motor and drill string to realize change wellbore trajectory, so friction force is large. The use reduction tools that generate axial state can only achieve partial reduction, still in a during drilling. These problems are solved by using rotary steerable system, which when rotates. But its cost high. Considering principle high efficiency economy, new tool called rotation controller proposed, also used reduce...

The field of geotechnical engineering is an important research direction in civil engineering, which has theoretical and practical value for deformation prediction rock soil mass. This study aims to propose efficient accurate method by introducing Long short time memory network (LSTM) algorithm, so as improve the traditional model meet requirements. Firstly, through a detailed literature review, existing methods problems are deeply understood. In methods, because complexity nonlinear...

In order to improve the ROP (rate of penetration) complex structure and deep wells reduce energy consumption rock breaking during drilling process, a core drill bit with negative pressure adsorption effect is developed. Rock-breaking consumption, ROP, carrying capacity new are studied. Numerical example conducted analyze relationship between characteristic parameters cutting velocity experimental tests carried out verify theoretical model results calculation examples. The indicate that...

Buckling may cause drill string damage or even drilling failure. For the 3[Formula: see text]000-m-long horizontal section string, a simplified analysis model of in well is established, and dynamic response results axial displacement, angular displacement contact force are obtained. When buckling, closer position to bottom, later buckling time, smaller deformation degree, slower growth rate attenuation degree amplitude. After undergoes tensile eventually remains stable state. stabilization,...

Erosion resistance is the evaluation indicator of performance parameter wall-attachment jet component, which key component oscillation tool. For erosion wear problem, research based on solid–liquid two-phase flow conducted. According to fluid dynamics and theory, Euler-Lagrangian method discrete phase model (DPM) are used establish internal discuss effect particle parameters. The interaction response main influence factors analyzed by surface (RSM). results show that degree channel...