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The optimal selection of fracturing interval for the exploitation of tight oil reservoirs is very important for formulating a development program. In this study, the reservoir quality and the reservoir fracability are evaluated, and the criteria for the optimal selection of the fracturing interval are established, using the tight reservoir in the the Qing I Member of Qingshankou Formation in the Daqingzijing Oilfield of China as the study site. The results indicate that the porosity, the oil saturation and the effective thickness of tight reservoir are keys to optimizing the fracturing interval. The brittleness index and the difference coefficient among the horizontal stresses in the reservoir have a strong influence on fracability. The stress difference coefficient in the reservoir is smaller and the reservoir develops microfractures, the complex mesh fractures are easier to occur during fracturing. The stress difference between the reservoir and the surrounding bed is small and the thickness of the surrounding bed is thin, it is easy to communicate with adjacent oil-bearing layers when fracturing.

The fracture samples of the hard cladding material 5Cr2Ni08C/Q235 are fabricated with the vacuum liquid phase sintering technology, three-point bending fracture experiments are conducted, the sample fracture morphology are observed with SEM. The experiment research results show that: the intergranular micro-crack is easy to initiate in the interface under the action of the external load, and the micro-crack easily appears on the crystal boundary, the thermal expansion coefficient mismatch places, around the interface contamination and micro holes. Based on which, the interface micro-crack easily continues to propagate along the crystal boundary. And the micro-mechanisms of the interface crack initiation and propagation are established.

Introduction: Immunotherapy, especially immune checkpoint blockade (ICB), holds promise as a therapeutic strategy in colorectal cancer (CRC) by harnessing the patient's immune system to target malignant cells. Particularly, the PD-1/PD-L1 axis is widely recognized for its critical role in tumor microenvironment immunosuppression. Antibodies targeting PD-1 or PD-L1 have shown sustained efficacy against various cancers, including CRC. Nonetheless, many CRC patients exhibit limited responses to such immunotherapy, and the resistance mechanisms remain incompletely understood. Methods: We conducted experiments with C57BL/6 mice, and used the MC38 cell line for ICB treatment studies in syngeneic mouse models. Gene and protein analyses were performed using qPCR, Western Blot, and flow cytometry, with bioinformatics for clinical data survival analysis. Results: In this study, we reveal that targeting PD-L2 emerges as a complementary therapeutic strategy to PD-1/PD-L1 blockade in CRC. Although PD-L2 is also inducible by IFNγ, like PD-L1, it displays a unique spatial distribution within the tumor microenvironment, implying discrete roles in immune evasion. Additionally, we uncovered a significant correlation between PD-L1 and PD-L2 expression levels and the infiltration of various immune cells, encompassing multiple dendritic cell (DC) subtypes. This correlation implies an enhanced antigen presentation process that may be unleashed by blocking these two immune checkpoints. Discussion: Our results highlight the significance of PD-L2 as an essential immune checkpoint alongside PD-L1 and emphasize its potential as a target for bolstering antitumor immunity in colorectal cancer. [ABSTRACT FROM AUTHOR]

In addressing the critical issue of right-of-way conflicts in mixed-traffic environments, this paper introduces a novel shared right-of-way driving strategy that encompasses two guiding frameworks for resolution. The first framework applies to active lane changing. Before lane changing occurs, this framework allocates the right of way for autonomous vehicles (AVs). Based on the allocated right of way, the AVs decide whether to send a request for a shared right of way to relevant vehicles. To enhance lane-changing comfort, the vehicle assesses whether the variance of roll and lateral acceleration exceeds a preset threshold, ultimately deciding whether to proceed with the lane change. The second framework pertains to passive lane changing. After detecting an obstacle, this framework allocates the right of way. The AVs calculate acceleration based on their speed and distance from the obstacle, using this information to determine whether to change lanes or decelerate in order to avoid the obstacle. If lane changing is chosen, further evaluation is necessary. Based on the allocated right of way, the AVs decide whether to request a shared right of way from relevant vehicles. To improve lane-changing comfort, the AVs compare the variance of roll and lateral acceleration with that of pitch and longitudinal acceleration, and then they decide whether to proceed with the lane change. The proposed strategy has been validated in various scenarios, including high-speed (105 km/h), low speed (13 km/h), and general scenarios with AVs and obstacles at a distance of 125 m. The results show that the strategy effectively functions in both high-speed and low-speed scenarios. [ABSTRACT FROM AUTHOR]

Interface models of diamond-coated cemented carbide tool WC-Co / SiC/ Diamond with Co mass fraction of 6%, 8%, 10% and 12% were constructed. The influences of different deposition temperatures on the interface bonding strength were simulated with the molecular dynamics method, and the reasons were analyzed from perspectives of adhesion work and bond length distribution. The adhesion work analysis indicates that, compared with the other three Co content interface models, the two interfaces in WC-6% Co / SiC/ Diamond interface model have the highest adhesion work values at seven deposition temperatures. At different deposition temperatures, both interfaces of WC-6% Co / SiC and SiC/ Diamond in WC-6% Co / SiC/ Diamond have the highest adhesion work values of 2. 468 and 5. 394 J / m² at 1 123 and 1 173 K, respectively. The analysis results of bond length distribution indicate that, at any deposition temperature, compared with the other three Co content interface models, the maximum value of the bond length distribution range at each interface of WC-6% Co / SiC/ Diamond is smaller. The interface model obtained by sequentially depositing SiC layer on WC-6%Co substrate at 1 123 K and diamond coating on SiC layer at 1 173 K has the shortest interface bond length, the largest bond energy, and the best interface bonding property. Key words: diamond-coated cemented carbide; WC-Co / SiC/ Diamond; deposition temperature; Co content; interface [ABSTRACT FROM AUTHOR]

Hydraulic control valves are widely used in industrial production, agricultural equipment, construction machinery, and other large power equipment for controlling the pressure and flow of fluids in hydraulic systems. The driving method has a significant impact on the response and control accuracy of hydraulic valves. This paper reviews the driving methods of spools from five aspects: solenoid drive, material expansion drive, motor drive, hydraulic valve drive, and another drive. It summarizes the various schemes currently available for spool drive and analyzes each of them. After optimizing the driving method of the valve core, the control accuracy can reach 3%, and the minimum response time is 7 ms. According to the characteristics of the different drive methods, the differences between them are compared, the advantages and disadvantages of each drive method are analyzed, and the application scenarios for each drive method are identified. Solutions to the drawbacks of the existing drive methods are proposed, which provide directions for further optimization. We have found that solenoid drives are simple to control, low cost, and the most widely used. Material telescopic drives, motor drives, hydraulic valve drives, and other drives are costly, complex to control, and optional for use in special requirement situations. Based on the existing spool drive methods, an outlook on future drive methods is presented. This review facilitates a comprehensive understanding of the drive methods of hydraulic valve spools, points out the shortcomings of the existing drive methods, and is of great significance in improving the existing drive methods and proposing new drive methods. This paper has a positive effect on improving the control accuracy and responsiveness of hydraulic valves. [ABSTRACT FROM AUTHOR]

This study performed first-principle-based calculations of the interface adhesion work in interface models of three terminal systems: CrAlSiNSi/WC-Co, CrAlSiNN/WC-Co, and CrAlSiNAl/WC-Co. The results proved that the CrAlSiNSi/WC-Co and CrAlSiNAl/WC-Co interface models had the highest and lowest interface adhesion work values (4.312 and 2.536 J·m−2), respectively. Thus, the latter model had the weakest interface bonding property. On this basis, rare earth oxides CeO2 and Y2O3 were doped into the Al terminal model (CrAlSiNAl/WC-Co). Then, doping models of CeO2 and Y2O3 doped on the WC/WC, WC/Co, and CrAlSiNAl/WC-Co interfaces were established. The adhesion work value was calculated for the interfaces in each doping model. When CeO2 and Y2O3 were doped in the WC/WC and CrAlSiNAl/WC-Co interfaces, four doping models were constructed, each model contains interfaces withreduced adhesion work values, indicating deteriorated interface bonding properties. When the WC/Co interface was doped with CeO2 and Y2O3, the interface adhesion work values of the two doping models are both increased, and Y2O3 doping improved the bonding properties of the Al terminal model (CrAlSiNAl/WC-Co) more significantly than CeO2 doping. Next, the charge density difference and the average Mulliken bond population were estimated. The WC/WC and CrAlSiNAl/WC-Co interfaces doped with CeO2 or Y2O3, with decreased adhesion work, exhibited low electron cloud superposition and reduced values of charge transfer, average bond population, and interatomic interaction. When the WC/Co interface was doped with CeO2 or Y2O3, superposition of the atomic charge densities of electron clouds was consistently observed at the CrAlSiNAl/WC-Co interface in the CrAlSiNAl/WC/CeO2/Co and CrAlSiNAl/WC/Y2O3/Co models; the atomic interactions were strong, and the interface bonding strength increased. When the WC/Co interface was doped with Y2O3, the superposition of atomic charge densities and the atomic interactions were stronger than for CeO2 doping. In addition, the average Mulliken bond population and the atomic stability were also higher, and the doping effect was better. [ABSTRACT FROM AUTHOR]

Based on the first-principles method, TiAlSiN/WC-Co interface models with graphene doped into the matrix, coating, and the coating/matrix are constructed. The interface adhesion work is calculated and modeled to study the interface bonding properties from the atomic microscopic point of view. The results show that the interface bonding properties of TiAlSiN/WC-Co can be improved when the matrix is doped with the main surface of intrinsic graphene, and the interface bonding property of TiAlSiNN/WC-Co can be improved when the coating and coating/matrix are doped separately with the main surface of intrinsic graphene or single vacancy defective graphene. Furthermore, the model electronic structures are analyzed. The results show that there exist strong Si/Co and N/Co covalent bonds in the interfaces when the matrix is doped with the main surface of intrinsic graphene, which causes the adhesion work of TiAlSiN/WC/msGR/Co to be greater than that of TiAlSiN/WC-Co. Additionally, when the graphene is doped into the coating, in the interface of TiAlSiN/msGR/TiAlSiNN/WC-Co, there exist strong N/Co covalent bonds that increase the interface adhesion work. Additionally, more charge transfer and orbital hybridization exist in the coating/matrix interface doped with the main surface of intrinsic graphene or single vacancy defective graphene, which explains the essential mechanism that the adhesion work of TiAlSiNN/msGR/WC-Co is greater than that of TiAlSiNN/WC-Co, and the adhesion work of TiAlSiNN/svGR/WC-Co is greater than that of TiAlSiNN/WC-Co. [ABSTRACT FROM AUTHOR]