The assessment of drilling crew is crucial for evaluating the operational effectiveness, improving management levels, and improving drilling operation quality and efficiency. Currently, most drilling crew operation ev...
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This paperdiscusses permanent deformation of the fuel assembly of pressurized waterreactors that have to satisfy a drop time requirement of the control rod assembly. during a seismic event, the fuel assemblies and t...
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Thermal management of microprocessor chips has emerged as a critical issue to ensure high-power operation, especially in high-performance computing (HPC) applications such as artificial intelligence (AI). To effective...
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ISBN:
(数字)9798331522001
ISBN:
(纸本)9798331522018
Thermal management of microprocessor chips has emerged as a critical issue to ensure high-power operation, especially in high-performance computing (HPC) applications such as artificial intelligence (AI). To effectively transfer the heat generated from the chip junction to the heat spreader or heat sink, the development of thermal interface materials (TIMs) with high thermal conductivity and the processes for applying them are very active in the electronics packaging industry. In general, polymer-based TIMs have been widely developed and used for their mechanical properties and process workability. However, due to the limitations of polymers, the thermal conductivity required for HPC applications cannot be satisfied. Indium (In) has been widely selected for high power consumption devices as a high dielectric constant (k) TIM due to its high thermal conductivity. However, the low liquidus point of In can be problematic for flip chip lidded ball grid array (FCLBGA) applications since indium may be re-meltedduring ball attachment reflow, which can reduce TIM coverage [3]. In this paper, indium-silver (InAg)-based alloys were evaluated to develop high thermal conductivity TIM solutions that can be applied to large body FCBGA devices and examines the reliability of indium-silver alloy TIMs under thermal cycling conditions. By varying the silver content, we investigated its impact on mechanical stability and TIM coverage degradation. Indium alloy with higher silver content showedreduced package warpage and fewer voids, as observed through Shadow moire and SAT inspection. In contrast, Indium alloys with lower silver content exhibited more significant structural deformation and void formation Our findings suggest that increasing silver content in indium alloys enhances the TIM coverage and mechanical stability with better thermal performance
during ultradeep oil and gas drilling,fluid loss reducers are highly important for water-baseddrilling fluids,while preparing high temperature-and salt-resistance fluid loss reducers with excellent rheology and filtr...
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during ultradeep oil and gas drilling,fluid loss reducers are highly important for water-baseddrilling fluids,while preparing high temperature-and salt-resistance fluid loss reducers with excellent rheology and filtration performance remains a ***,a micro-crosslinked amphoteric hydrophobic association copolymer(i.e.,dAdC)was synthesized using N,N-dimethyl acrylamide,diallyl dimethyl ammonium chloride,2-acrylamido-2-methylpropane sulfonic acid,hydrophobic monomer,and pentaerythritol triallyl ether *** to the synergistic effects of hydrogen bonds,electrostatic interaction,hydrophobic association,and micro-crosslinking,the dAdC copolymer exhibited outstanding temperature-and *** rheological experiments have shown that the dAdC copolymer had excellent sheardilution performance and a certain degree of salt-responsive viscosity-increasing *** dAdC copolymer could effectively adsorb on the surface of bentonite particles through electrostatic interaction and hydrogen bonds,which bring more negative charge to the bentonite,thus improving the hydration anddispersion of bentonite particles as well as the colloidal stability of the drilling ***,the drilling fluids constructed based on the dAdC copolymer exhibited satisfactory rheological and filtration properties(FLHTHP=12 m L)after aging at high temperatures(up to200℃)and high salinity(saturated salt)***,this work provided new insights into designing and fabricating high-performance drilling fluid treatment agents,demonstrating good potential applications in deep and ultradeep drilling engineering.
NbC ceramic surface-reinforced steel matrix composites were prepared by an in-situ reaction method at different temperatures(1,050℃,1,100℃and 1,150℃)fordifferent times(1 h,2 h and 3 h).The phase constitution,micro...
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NbC ceramic surface-reinforced steel matrix composites were prepared by an in-situ reaction method at different temperatures(1,050℃,1,100℃and 1,150℃)fordifferent times(1 h,2 h and 3 h).The phase constitution,microstructure and fracture morphology of NbC ceramic surface-reinforced steel matrix composites were analyzed by Xrd,SEM and EdS,and the effects of the in-situ reaction temperature and time on the mechanical properties were systematically *** results indicate that the NbC reinforcement layer is formed through the reaction between Nb atoms and carbon atoms diffused from the steel matrix to the Nb *** thickness of this reinforcement layer increases as the reaction time ***,an increase in reaction temperature results in a thickerreinforcement layer,although the rate of increase gradually *** relationship among the thickness of the Nb C reinforcement layer,the reaction time and temperature was established by data *** optimal tensile performance is achieved at 1,100℃for 1 h,with a tensile strength of 228 *** is also found that the defects between the reinforcement layer and the steel matrix are related to reaction *** 1,100℃,these defects are *** mostly occurs in the NbC reinforced layer of the composites,and the fracture mode is characterized by typical intergranular brittle fracture.
Polymer flooding is very promising chemical enhanced oil recovery technique because it has been widely field tested in many oil fields and commercially applied in several countries in onshore reservoirs. The understan...
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The acid leaching residue(ALr)of ionic rare earth(IrE)concentrates containing radioactive elements such as thorium(Th)is classified as low-level radioactive *** holds valuable strategic resources such as rare earth an...
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The acid leaching residue(ALr)of ionic rare earth(IrE)concentrates containing radioactive elements such as thorium(Th)is classified as low-level radioactive *** holds valuable strategic resources such as rare earth and Th,while improper long-term heaping storage of ALr poses a substantial environmental *** paper proposes a comprehensive process involving low-temperature roasting,hydrochloric acid leaching,single extractant enrichment,and stepwise stripping to recoverrare earth elements and thorium from *** achieved leaching efficiencies are 80.11%of LnY,99.43%of Sc(Ⅲ),and 98.67%of Th(Ⅳ)after the carbonization of the organic phase in the ALr through low-temperature *** large amounts of acid and impurities present in the leachate,2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester(HEHEHP)still exhibits nearly 100%extraction efficiency for Sc(Ⅲ)and Th(Ⅳ).The effective separation of LnY,Th(Ⅳ),and Sc(Ⅲ)was achieved by implementing fractional extraction enrichment of Th(Ⅳ)and Sc(Ⅲ),followed by Th(Ⅳ)removal through H_(2)SO_(4)and Sc(Ⅲ)removal via NaOH from the loaded organic *** scheme successfully achieves a recovery of rE and Th and offers a viable solution for the safe disposal of ALr.
Heart rate variability (HrV) analysis in a wristband photoplethysmography (PPG) device is gathering interest for emotion and stress recognition. However, motion artifacts are a critical issue, and comprehensive evalua...
Heart rate variability (HrV) analysis in a wristband photoplethysmography (PPG) device is gathering interest for emotion and stress recognition. However, motion artifacts are a critical issue, and comprehensive evaluation from HrV analysis to the model performance and interpretability should be conducted. In this study, we constructed a physiologically interpretable evaluation framework of HrV analysis and acute stress recognition using a deep neural network (dNN) in a wrist-worn PPG device compared with that in a chest-worn electrocardiography (ECG) device, considering motion artifacts, which are an important issue in wild environments. Furthermore, we developed model training and testing methods using a dNN that takes signal quality into account to achieve both accuracy (robustness against motion artifacts) and model interpretability in acute stress recognition in the wrist-worn PPG device. The results suggest that the method we developed improved the acute stress recognition performance of the wrist-worn PPG device throughout our experiments (78.4% accuracy and 77.0% F1 score). In addition, it was observed that the method for the wrist-worn PPG device demonstrated comparable performance and interpretability to the reference method for the chest-worn ECG device.
The quality of drilling wellbore is crucial for oilfield companies to evaluate the construction acceptance of drilling operations, evaluate the wellbore quality before cementing operations, and smoothly implement subs...
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ISBN:
(纸本)9789819702558
The quality of drilling wellbore is crucial for oilfield companies to evaluate the construction acceptance of drilling operations, evaluate the wellbore quality before cementing operations, and smoothly implement subsequent casing and electrical logging tools. At present, the evaluation of wellbore quality only requires dispersed trajectory parameters of different well sections (well inclination angle, dog leg angle, target range), and only considers whether the trajectory parameters are within the qualifiedrange during completion acceptance. A quantitative scoring method for wellbore quality has not yet been developed, which is not conducive to the evaluation of well quality by oilfield enterprises during drilling completion acceptance. In this paper, the key parameters such as deviation measurement interval, dogleg degree, maximum deviation and target hit are comprehensively considered. Based on the comprehensive method of mathematical statistics and Matlab programming calculation, a multi-level quantitative scoring model of well bore quality is established. The key parameters in the multi-level quantitative model of well bore quality are determined by using the main control factor analysis method of random forest algorithm. Taking the A oil field as an example, a quantitative scoring was conducted on the quality of 74 drilled wells in 2021 to evaluate the effectiveness of the operation team in controlling well quality. The analysis results showed that for the A oil field, the importance of factors affecting well quality was as follows: maximum inclination > Target radius > dog leg = survey interval. Crew 1 had better control over well quality, and the proportion of high-quality wells in 2021 decreased compared to 2020, The analysis results of the multi-level well bore quality quantification method based on random forest algorithm proposed in this paper are in line with the field work practice, which provides a theoretical basis for well bore quality quantificati
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