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Fault-slip rockbursts are a major type of rockbursts in coal mine roadways, posing great hazards. Currently, there is a lack of systematic research on the entire process of fault-slip rockbursts, and prediction and prevention remain fundamental challenges. To achieve experimental simulation of fault-slip rockbursts, a testing system was developed, along with the development of low-strength high-brittleness similar simulation materials. A large-scale similar model containing faults and roadways was prepared, and a series of verification experiments were conducted, realizing the simulation of roadway shock failure and fault shear slip. The testing system is equipped with a triaxial six-face loading function, with a vertical loading capacity of 20 MPa and a model size of 1.50 m×0.75 m×0.75 m. The main frame innovatively adopts a key plate connection, ensuring high rigidity of the main frame. A honeycomb loading shell structure was invented, achieving oil cylinder group loading, which can meet the requirements of fault-slip rockburst simulation. A similar material suitable for fault-slip rockburst simulation was developed, which uses water glass as the binder, sodium fluosilicate as the curing agent, and talcum powder as the aggregate. The similar material has characteristics of both low strength and high brittleness, with a uniaxial compressive strength ranging from 3.44 to 7.81 MPa, an impact energy index of 9.2, and an elastic energy index of 8.83. Based on the test system and low-strength and high-brittleness materials, the bursting failure simulation of roadway under static load was realized, and the feasibility of simulating bursting failure of roadway using low-strength and high-brittleness materials was verified. The loading conditions of the critical equilibrium state of the roadway were obtained, with the continuous shedding of the roadway's side as a significant precursor characteristic of roadway damage. The shear slip of rough serrated faults was realized, confirming that the shear slip of rough faults would cause significant dynamic load disturbances to the roadway, obtaining a reasonable loading method for fault slip. The method of loading the top of the dynamic zone first and unloading the bottom later can achieve instantaneous slip of the fault and eliminate the influence on the static zone stress state.

Objective: Hot air coupled with ultrasound and infrared irradiation were used for the drying of curdlan. The drying mechanism and quality change of curdlan were explored under the multi-physical fields, so as to developing the green drying technology of curdlan. Methods: Forced convective hot air alone, ultrasound-coupled forced convective hot air, infrared irradiation alone, and infrared-coupled forced convective hot air were used to dry curdlan. A mass transfer model considering temeprature change was constructed and the quality of the dried curdlan was comprehensively assessed. Results: Under the studied forced convective hot air drying conditions, it took around 40 min to dry the curdlan, and the required drying time was reduced to 36, 26 and 22 min for ultrasound-coupled hot air drying, infrared irradiation alone drying, and infrared-coupled hot air drying, respectively. The moisture transfer model coupled with the temperature change was able to accurately predict the change of the moisture content throughout drying. Under infrared drying coupled with convective hot air, the range of moisture effective diffusivity inside curdlan was 9.79×10−9 to 9.81×10−9 m2/s, and the surface mass transfer coefficient was 4.69×10−2 kg water/(m2·s), which were higher than those of the other treatment groups, followed by those under infrared irradiation alone drying, ultrasonic-coupled hot air drying, and hot air drying alone. Moreover, the gel strength, glucose content, the distribution of chemical functional groups on surface, crystal structure and thermal stability of curdlan samples dried by different methods were all similar. Conclusion: Taking all these results into consideration, infrared drying was regarded as an efficient method for drying curdlan compared to hot air drying and ultrasound-coupled hot air drying.

In order to provide reliable communication service for high-mobility scenarios, 6G can consider DD (delay-Doppler) domain based OTFS (orthogonal time frequency space) as its modulation scheme.By mapping the transmitted symbols onto DD domain and transforming them into TF (time-frequency) domain, OTFS endows all the transmitted symbols with the potential of capturing time-frequency full diversity, effectively improving the performance of communication in time-varying fading channels.Due to the superior properties of DD effective channel, the existing OTFS channel estimation methods were mostly carried out in DD domain.Considering the difference of implementation and application scenarios, existing DD channel estimation methods for OTFS were divided into three categories and overviewed, after which the challenges and potential solutions for current DD channel estimation methods were summarized and analyzed.

With the rapid development of national cities, the demand for urban underground space exploration development and utilization has increased. Due to the interference factors in human activities areas, traditional geophysical methods can't obtain true and accurate detection data. The microgravity method is relatively less affected by interference factors. The interference from urban buildings and human activities can be eliminated by the method of model forward correction, so as to obtain high-precision gravity collection data, and then the spatial location information of tunnel, goaf, cavity, collapse area and pipe gallery in urban underground space can be obtained through effective inversion method. In this paper, through experimental detection and analysis of the theoretically affected factors in the urban detection carried out by the ground mobile high-precision gravity measuring instrument, combined with the forward model correction research, the microgravity method shows good effect in the detection of urban underground space.

The undeveloped low-permeability oil reserves of the Liushagang Formation in the Beibu Gulf Basin are large, but the reservoir quality is poor. The existing classification standards for low-permeability reservoirs cannot meet the needs of fine reservoir evaluation and offshore development.Based on the experiments of constant rate mercury injection, high pressure mercury injection, NMR and seepage mechanism, this paper comprehensively analyzed the micro-pore structure and seepage characteristics, and optimized six kinds of reservoir evaluation parameters: reservoir quality index, fractal dimension of pore structure, mainstream throat radius, mean throat radius, percentage of movable fluid and change rate of threshold pressure gradient, meanwhile, the classification limit of various characterization parameters were determined by integrating with the reservoir quality index, reservoir seepage ability evaluation factors and specific productivity index constraint parameters. A comprehensive evaluation criterion for low-permeability oil reservoirs is established based on the Grey Relational Analysis method, which is divided into Ⅰ, Ⅱa, Ⅱb, Ⅲ and Ⅳ from good to bad.Carried out the grading evaluation of low-permeability reserves and the research results provide a theoretical basis for the analysis of the development potential, the research direction of the low-permeability reserves in Beibu Gulf Basin.The results show: types Ⅰand Ⅱa are relatively high-quality low-permeability reserves and have been put into large-scale development.Types Ⅱb and Ⅲ are extra-low-permeability reserves and are difficult to develop, which need to be formulated for experimental development by reasonable technical measures and development models.

In the enclosed spaces,wireless transmissions lead to the strong interferences of reflection signals,because of multipath effects.However,how to reduce the reflection signal effect on wireless transmissions is a kernel problem to expand the application scope of Internet of things.The time-aware retransmission MAC (TR-MAC) was proposed,which can adjust the time delay of each frame and reduce the interference caused by the reflected signal by using the reflection loss of the space conductor surface.In order to prove the adaptability of TR-MAC,an experimental environment that can generate strong reflection interference signals was used.The experimental results proved the feasibility and effectiveness of the TR-MAC in different environments.In a sense,TR-MAC extends the application of wireless communication in strongly reflective space.Besides,in the application of the Internet of things in the aircraft,ship and satellite,TR-MAC can realize wireless transmission instead of part of the wired transmission,so as to improve the system reliability,effective weight reduction and other important goals.

Taking a deep-water exploration well of natural gas located in the Qiongdongnan Basin in the South China Sea as an example, the hydrate risks of the well under operational conditions during drilling and testing processes were analyzed, and the corresponding hydrate prevention solutions were presented and verified by lab experiments and field application. Based on the predicted gas hydrate equilibrium curves and the calculated wellbore pressure-temperature fields, the hydrate risks were analyzed. The maximum sub-cooling temperature is 6.5 °C during normal drilling with a small hydrate stability zone in the wellbore; when the drilling or testing stops, the hydrate stability zone in the wellbore becomes larger and the maximum sub-cooling temperatures are 19 °C and 23 °C respectively; the maximum sub-cooling temperature at the beginning of testing is no more than that when testing stops; when the tested production rate of natural gas increases, the hydrate stability zone in the wellbore decreases or even disappears if the gas rate is more than 25×104 m3/d. The designed hydrate prevention solutions include: adding sodium chloride and ethylene glycol into drilling fluid during normal drilling and when drilling stops; adding calcium chloride/potassium formate and ethylene glycol into testing fluid; applying downhole methyl alcohol injection when the production rate of natural gas is lower than 25×104 m3/d; filling the testing string with testing fluid when the test shuts down for a long time. Lab experiments and field operations have indicated that all the designed solutions can meet the requirements of hydrate prevention. Key words: gas hydrate, drilling fluid, wellbore temperature, sub-cooling temperature, hydrate inhibitor, deep water drilling

Background and objective Software oriented three-dimensional (3D) volumetric measurement of pulmonary nodules has been feasible in the follow-up of indeterminate pulmonary nodules, however, its value need a further validation. The purpose of this study is to retrospectively analyze the chest CT data of patients with pulmonary nodules to compare the intra-observer variability of 3D and two-dimensional (2D) volumetric measurement. Methods Eighty-six pulmonary nodules in chest CT scans of 79 subjects were retrospectively analyzed. One radiologist measured the nodules twice with a 7 days interval using 2D and 3D methods respectively. The maximal diameter (X), the perpendicular diameter (Y) on maximal cross sectional area of the nodule and the caudo-cranial diameter (Z) were measured and the volume was calculated by two models: spherical and elliptical model. The 3D measurements were acquired with semi-automated software with manual adjustment on unsatisfied nodule segmentation. Logistic regression analysis was performed to evaluate the effect of nodule location and morphology on 3D nodule segmentation. ANOVA and correlation test were used to evaluate the difference among three methods. Bland-Altman method was applied to quantify the intra-observer variability. Results Software achieved satisfied segmentation for 86.4% nodules. The irregular and juxtavacular nodules have significantly high odds rations (OR) of unsatisfied segmentation as 4.0, 4.5, respectively. The volume measured by three method was significantly different (F=6.5, P=0.012), while the repeated measurements did not led to significant difference (F=1.813, P=0.182). The Spearman correlation efficient between 3D volume and 2D volume with sphere and ellipsoid model was 0.97, 0.88. The 95% limits of agreement of RD between two repeated measurements were -14%-11.6%, -37.7%-39.9% and -39.8%-45.8% for 3D, 2D with elliptical model and spherical model, respectively. Conclusion The 3D volume measurement of pulmonary nodules is more repeatable than 2D volume measurement. Unsatisfied segmentation can occurred on a small number of nodules, especially for irregular and juxtavascular nodules. For these nodules, the measurement of 3D diameters is recommended.

Background and objective Chest computed tomography (CT), particularly thin-slice high resolution CT, has low sensitivity and specificity for detecting pulmonary nodules

Background and objective The histologic type and grade of lung cancer are significant in assessing the biological behaviour, prognosis and therapeutic regimen. This study investigates the correlation of apparent diffusion coefficient (ADC) with histologic type and grade of lung cancer. Methods A total of 115 patients pathologically diagnosed with lung cancer were enrolled in this study. Magnetic resonance (MR)-DWI with a diffusion factor of 500 s/mm2 was performed and the ADC values of lesions were measured. The ADC values among the different histologic types and grades were compared with the values obtained using t-test and one-way ANOVA. The correlation between ADC values and the histologic grades was further evaluated with Spearman correlation coefficient. Results With a b value of 500 s/mm2, the ADC values significantly differed between small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) (P=0.017). The ADC values of SCLC were significantly different from those of squamous cell carcinoma and adenocarcinoma (P=0.011, 0.001, respectively). A significant difference was observed in the ADC values among the different histologic grades of lung cancer (P=0.003), and the ADC value was correlated with the histologic grades (rs=-0.272, P=0.003). Conclusion ADC value is significant for judgement of histologic type and grade of lung cancer before surgical operation: SCLC has a low ADC value, and ADC value is low for the tumor with poorly-differentiated grade.

急性缺血性卒中梗死核心体积（infarct core volume，ICV）的形成是由脑血管闭塞导致的脑组织出现不可逆性损伤，可对卒中的预后以及治疗选择产生最直接的影响。基于影像学技术的发展，ICV可以通过不同的影像学方法显示出来，但应重视当前成像存在的局限性。本研究对不同影像评估ICV的应用进行综述，为临床选择治疗策略提供依据，从而改善患者的预后。 Abstract: The formation of infarct core volume (ICV) in acute ischemic stroke is due to the irreversible injury of brain tissue caused by cerebral vascular occlusion, which has the most direct influence on the prognosis and treatment choice of stroke. Based on the development of imaging technology, ICV can be shown by different imaging methods, but the limitations of current imaging should be paid attention to. In this study, the application of different imaging assessment of ICV was reviewed to provide a basis for clinical treatment strategies to improve patient prognosis.

Background Renal cell carcinoma (RCC) is characterized by insidious onset, lack of early typical clinical manifestations, metastasis or advanced stage at diagnosis in most patients and poor efficacy of radical nephrectomy. In recent years, with the broadly application of targeted therapies in tumors, the postoperative recurrence and mortality rates have been greatly reduced. However, there is a lack of evidence for the efficacy and safety of clinical treatment due to the existence of certain adverse effects and complications. Objective To systematically review the efficacy and safety of programmed death-1 (PD-1) /programmed death-1 ligand (PD-L1) inhibitors in the treatment of RCC. Methods CNKI, Wanfang Data, VIP, PubMed, Web of Science, Embase, Cochrane Library, Clinical Trials and other English databases were searched by computer and manually for the randomized controlled trials of PD-1/PD-L1 inhibitors for RCC from the inception to 2022-09-30. Two researchers independently extracted and collated the data, evaluated the quality of the included literature according to Cochrane 5.3 manual criteria, and performed meta-analysis using RevMan 5.4 software. Results A total of 11 papers were finally included, involving 7 895 study subjects with 3 936 cases in the trial group and 3 959 cases in the control group. Meta-analysis results showed that the overall survival (OS) and progression-free survival (PFS) were better in the trial group than in the control group〔HR=0.87, 95%CI (0.84, 0.90), P0.05, indicating no significant publication bias among studies. Conclusion PD-1/PD-L1 inhibitors for RCC can significantly improve and enhance OS, PFS, ORR, CR, PR and DCR in patients without increasing the incidence of adverse effects in terms of safety, thus confirming the superiority of PD-1/PD-L1 inhibitors for RCC in terms of clinical efficacy and safety.

Superhydrophobic surfaces have a contact angle(CA) greater than 150° and a sliding angle(SA) smaller than 10°, which can prevent water from penetrating into the structure under dynamic impacts, and thus can be used in high-end fields such as self-cleaning and anti-corrosion. Natural objects such as lotus leaves and rose petals were taken as the prototypes of artificial superhydrophobic surfaces. The main problem of self-cleaning superhydrophobic surfaces is that they are susceptible to mechanical instability and may lose superhydrophobicity after wear/scratch. However, the development of nanotechnology has brought many advantages to the preparation and performances of superhydrophobic surfaces. Many scientific groups have reported that graphene and its derivatives exhibited superhydrophobic properties. Therefore, with the help of this outstanding two-dimensional material, superhydrophobic surfaces with excellent mechanical durability, self-cleaning performance and corrosion resistance can be generated. This work focused on introducing the preparation strategies and corresponding properties of superhydrophobic graphene-based materials. It was also anticipated that the incorporation of superhydrophobic and graphene-based materials would bring new opportunities for the development of many high-performance equipment.

BackgroundAcquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) will eventually occur in almost all advanced EGFR-mutant non-small cell lung cancer (EGFR-mutant NSCLC) patients although the therapy has been a standard treatment for such patients. But EGFR-TKIs in combination with anti-angiogenic drugsmay prolong the survival time of these patients.ObjectiveTo explore the efficacy and safety of EGFR-TKIs with anti-angiogenic drugs as the treatment for patients with advanced EGFR-mutant NSCLC.MethodsDatabases including CNKI, CQVIP, Wanfang Data Knowledge Service Platform, PubMed, EMBase, and The Cochrane Library were searched from inception to July 2021 using subject headings with free-text words, for randomized controlled trials (RCTs) about the first-line treatment of advanced EGFR-mutant NSCLC patients with EGFR-TKIs in combination with anti-angiogenic drugs (combination therapy group) versus EGFR-TKIs alone (monotherapy group) . Two researchers performed literature screening, data extraction (the first author, publication time, the country where the author coming from, study type, sample size, stage of NSCLC, sex, average age, treatment regimen, ECOG PS score, median follow-up time, pathological type, gene mutation type, outcome indicators) , separately, and assessed risk of bias in the included RCTs. STATA 15.0 was used formeta-analysis.ResultsNine RCTs were included, involving 1 553 patients. Meta-analysis results showed that the combination therapy was associated with longer progression-free survival (PFS) 〔HR=0.61, 95%CI (0.54, 0.70) , P0.05) . Moreover, the combination therapy was not superior to monotherapy in terms of prolonging the overall survival, and improving the objective response rate, and disease control rate (P>0.05) . However, the rate of adverse eventsabove grade 3〔RR=1.77, 95%CI (1.62, 1.94) , P