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This Letter demonstrates a high-performance 3.3 kV-class β-Ga2O3 vertical heterojunction diode (HJD) along with an investigation into its off-state leakage mechanism. The vertical β-Ga2O3 HJD with field plate assisted deep mesa (FPDM) termination was fabricated using a self-aligned technique to etch the deep mesa to a depth of 9 μm, thereby reducing electric field crowding at the anode edge. In addition, a thick dielectric is deposited to fill the trench, facilitating the utilization of a field plate to further reduce the electric field at the anode edge. TCAD (Technology Computer Aided Design) simulations show significant suppression of electric field crowding at the anode edge. The fabricated HJD exhibits a high current swing of ∼1010 over a temperature range from 25 °C to 175 °C. The specific on-resistance (Ron,sp) is extracted to be 3.9 mΩ cm2, and the breakdown voltage is 3.42 kV with the FPDM termination. These conduction and blocking characteristics lead to a high power figure of merit of 3 GW/cm2, which is one of the highest among multi-kilovolt β-Ga2O3 diodes. Furthermore, the off-state current leakage mechanism of the HJD under a reverse bias up to 2000 V was investigated. The fitted results reveal that the leakage current is primarily dominated by Poole–Frenkel (PF) emission, with the trap level of PF extracted to be 0.36 eV below the conduction band of NiO. [ABSTRACT FROM AUTHOR]

Microbial grouting technology based on microbially induced calcite precipitation (MICP) is a new soil improvement method. This technique involves injecting bacteria and a cementation solution into soil pores to generate CaCO3 precipitation, thereby enhancing soil strength. Studies on microbial grouting from the aspects of experimental studies, theoretical models and engineering applications were extensively reviewed. Factors such as grouting methods, grouting rate, cementation solution concentration, and pH significantly influence the size and distribution of CaCO3. The three-phase grouting method enhances bacterial adsorption and soil strength. The higher grouting rate (grouting rate greater than reaction rate) and low pH (pH is not lower than 4) facilitate the uniform distribution of CaCO3. The size of CaCO3 and the soil strength increase with increasing cementation solution concentration. The existing models were established based on equilibrium flow, which overlooks the reduction of solute migration distance caused by the non-uniformity of the medium. Micro-structural analysis shows that CaCO3 precipitation between adjacent soil particles acts as a matrix supporting to increase soil strength. Microbial grouting technology can employ CaCO3 precipitation to seal wellbore cracks for CO2 storage and cement soil particles for slope stability and foundation improvement. Finally, the challenges encountered in microbial grouting technology were discussed. [ABSTRACT FROM AUTHOR]

Purpose: Although brain metastasis (BM) from gastric cancer (GC) is relatively uncommon, its incidence has been increasing owing to advancements in treatment modalities. Unfortunately, patients diagnosed with BM from gastric cancer have poor life expectancy. Our study aims to establish a predictive model for brain metastasis in advanced gastric cancer patients, thus enabling the timely diagnosis of brain metastasis. Patients and Methods: The clinicopathological features of a cohort which included 40 GC patients with brain metastasis, 32 of whom from the First Affiliated Hospital of Nanchang University, 2 from Gaoxin Branch of the First Affiliated Hospital of Nanchang University, remaining 6 from Anyang District Hospital, and 80 non-metastatic advanced GC patients from the First Affiliated Hospital of Nanchang University between 2018 and 2022. Data were retrospectively analyzed. Results: Age, tumor size, differentiation, lymph node grade, tumor location, Lauren classification, liver metastasis, carbohydrate antigen 199 (CA199), lactate dehydrogenase (LDH), and human epidermal growth factor receptor 2 (Her-2) were associated with BM. A nomogram integrated with nine risk factors (tumor size, differentiation, lymph node grade, tumor location, Lauren classification, liver metastasis, CA-199, LDH, and Her-2) showed good performance (Area Under Curve 0.95, 95% CI: 0.91– 0.98). Conclusion: We developed and validated a nomogram that achieved individualized prediction of the possibility of BM from GC. This model enables personalized imaging review schedules for timely brain metastasis detection in advanced gastric cancer patients. [ABSTRACT FROM AUTHOR]

Batch interface tracking and contamination control are the key technologies for the operation and management of multiproduct pipelines. Existing studies only focused on sequence arrangement or segment stoppage to control the generated contamination, and few considered this problem comprehensively and systematically. This study fully considers the contamination control process and develops a scheduling model for straight pipelines to minimize the cost of contamination loss caused by segment stoppage. The objective of this model is to minimize the restart cost of idle segments and the penalty cost due to improper interface placement during segment stoppage. Three types of constraints for contamination control are proposed, namely operation control, flow rate control, and stoppage control. Three real-world multiproduct pipelines are used as examples to validate the proposed method. Compared with the actual operation schemes, the method helps to reduce the number of stoppage operations by 20%–50%, and decrease the probability that the interface is improperly located by 40%–67%. Therefore, this work can reduce the cost of contamination treatment and bring greater benefits to pipeline operators. [ABSTRACT FROM AUTHOR]