The Jinping Underground Laboratory is the deepest and largest underground laboratory in the world,with a maximum buried depth of approximately 2400 m.The objective is to study the brittle-ductile transition of marble ...The Jinping Underground Laboratory is the deepest and largest underground laboratory in the world,with a maximum buried depth of approximately 2400 m.The objective is to study the brittle-ductile transition of marble through a combination of experimental research and constitutive modeling.Triaxial compression and triaxial cyclic loading tests are initially conducted to explore the accumulation of pre-peak plastic strain and the deterioration of stiffness of the marble.Then,a specific constitutive model is developed to accurately reflect the pre-peak plastic hardening and post-peak strain softening behaviors based on the deformation and failure mechanism of the marble.The incremental constitutive relationship of the proposed model is subsequently derived in detail,and the model parameters are calibrated using data obtained from the test results.Finally,the effectiveness of the proposed model is assessed by comparing its results with the experimental results of the marble.The findings show that the proposed model accurately predicts the behavior of the marble,and its results are in good agreement with the test data.展开更多
Fluid seepage and associated heat transfer within the enhanced geothermal system(EGS)regulate the extraction of heat from hot,low-water-saturation thermal reservoirs,sometimes referred to as hot dry rock(HDR).To under...Fluid seepage and associated heat transfer within the enhanced geothermal system(EGS)regulate the extraction of heat from hot,low-water-saturation thermal reservoirs,sometimes referred to as hot dry rock(HDR).To understand these complex heat recovery processes,we simulated long-term heat extraction in a surrogate HDR using a true triaxial apparatus.A circulation test was first implemented to analyze the connectivity between different wells.Suitable injection and production wells were then selected for the laboratory heat extraction tests in granite,which lasted 14.5 h.Under variable injection rate conditions,we systematically analyzed the time-varying curves of temperature and flow rate in the production wells and pressure in the injection wells.Our findings showed that the advantage channel was dominant in the flow distribution when several paths existed in EGS.Changes in fracture conductivity are attributed to injection pressure.These included an increase in fracture width and activation of a localized closed area of fracture.These two mechanisms influenced the production temperature,and this is consistent with the field data monitored at the Fenton Hill and Hijiori projects.Fluid leak-off was an important factor affecting the production flow rate.For a fracture with low hydraulic conductivity,a lower injection rate could effectively prevent excessive fluid leak-off.In addition,by comparing injection rates and fluid recovery rates,production wells in different phases or injection modes had different fluid recovery rates even when the injection rates were the same.展开更多
In 2024, the MOE Key Laboratory of Macromolecular Synthesis and Functionalization at Zhejiang University continued its impactful researches across five core areas. In controllable catalytic polymerization,organoboron ...In 2024, the MOE Key Laboratory of Macromolecular Synthesis and Functionalization at Zhejiang University continued its impactful researches across five core areas. In controllable catalytic polymerization,organoboron catalysts were developed for CO_(2) copolymerization and novel photoresist materials. Studies in microstructure and rheology elucidated universal deformation modes in graphene-based 2D membranes and improved graphene fiber properties through shear alignment engineering, defect control, and enhanced interlayer entanglement. For separating functional polymers, Janus membranes and channels were created for multiphase separation, liquid-phase molecular layer-by-layer deposition technique was developed to fabricate aromatic polyamide nanofilms, and the harmonic amide bond density was established as a valuable parameter for polyamide structural analysis. In biomedical functional polymers, a sustainable carboxyl-ester transesterification strategy was proposed for upcycling poly(ethylene terephthalate)(PET) waste into biodegradable plastics. Additionally, immunocompatible biomaterials were designed utilizing zwitterionic polypeptides and albumin-derived coatings, and Cu2+-phenolic nanoflower was designed to combat fungal infections by combining cuproptosis and cell wall digestion. Further,the researchers developed a gelatin-DOPA-knob/fibrinogen hydrogel to achieve rapid and robust hemostatic sealing, utilized a double-network polyelectrolyte-coated hydrogel for enhancing endothelialization of left atrial appendage(LAA) occluders, and the researchers also demonstrated that image-guided highintensity focused ultrasound enables manipulation of shape-memory polymers. Finally, in the realm of photo-electro-magnetic functional polymers, precise control of through-space conjugation was shown to enhance organic luminescence. Topologically structured hydrogels were revealed to exhibit autonomous actuation. Also, solar-driven photothermal ion pumps were developed for selective lithium extraction from seawater, and high-performance non-solvated C60single-crystal films were prepared via facile bar coating. Lastly, the researchers demonstrated outstanding dielectric properties of polyethylene(PE) lamellar single crystals. The relevant works are reviewed in this paper.展开更多
To advance the theoretical understanding,technological development,and field application of electric charge induction for monitoring rock deformation and failure,this study investigates the induced electric charge gen...To advance the theoretical understanding,technological development,and field application of electric charge induction for monitoring rock deformation and failure,this study investigates the induced electric charge generated during the deformation and failure of igneous rocks.The charge originates mainly from a combination of electrical polarization and triboelectric effects.Through laboratory experiments,we analyzed the time-frequency evolution of induced electric charge signals and identified relevant monitoring parameters.An online downhole electric charge induction monitoring system was developed and validated in the field.Experimental results show that the dominant frequency range of induced electric charge signals generated during igneous rock deformation and failure lies between 0 and 23 Hz,and a low-pass finite impulse response(FIR)filter effectively suppresses noise.Optimal sensor distances for monitoring cubic and cylindrical specimens were determined to be 17 mm and 13 mm,respectively.We proposed early warning indicators,including the maximum absolute value of the induced electric charge,the arithmetic mean value,the distribution dispersion coefficient,and the cumulative sum value.In field application,time-domain curves and spatial distribution charts of these warning indicators correspond well with changes in abutment stress ahead of the mining face,offering indirect insights into local stress evolution.This research provides technical and equipment support for the application of electric charge induction technology to monitoring and early warning of coal bursts.展开更多
In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics...In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.展开更多
Investigating the mechanisms underlying central nervous system disorders is a major scientific issue in the 21st century.However,the inaccessibility and complexity of the human brain have always represented a challeng...Investigating the mechanisms underlying central nervous system disorders is a major scientific issue in the 21st century.However,the inaccessibility and complexity of the human brain have always represented a challenge in understanding the pathophysiology of the central nervous system.Brain organoids are self-assembled threedimensional aggregates derived from pluripotent stem cells with cell types and structures similar to the embryonic human brain,giving them potential for investigating the atypical cellular,molecular,and genetic characteristics characteristic of central nervous system disorders.Brain organoids also provide a platform for drug screening and serve as a potential source for transplantation therapy for brain injuries.However,the broad application of brain organoids is hampered by several limitations,such as the lack of high-fidelity cell types,insufficient maturation,and considerable heterogeneity,undermining their reliability in specific applications.This review summarizes brain organoid evolution,discusses recent technological and methodological innovations,and reviews their applications in drug screening,transplantation therapy,and disease modeling,as well as clinical research progress.Additionally,we emphasize the limitations of current brain organoid research and explore the potential for advancing the technology to enhance its applicability.展开更多
Editorial message Every advancement in the field of laboratory animal science and technology,from exploring basic mechanisms to validating the development of new drugs,and from establishing disease models to respondin...Editorial message Every advancement in the field of laboratory animal science and technology,from exploring basic mechanisms to validating the development of new drugs,and from establishing disease models to responding to public health emergencies,strengthens the foundation for human health and well-being,serving as an important cornerstone for promoting global scientific innovation.For this reason.展开更多
Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These roc...Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These rock masses are predominantly composed of sedimentary,para-metamorphic,and volcanic rock types,characterized by a set of prominent,primary bedding structural planes(layers)exhibiting relatively consistent orientations and significant spatial continuity.展开更多
The clinical application of solid lipid particles(SLPs)is hampered due to the need for advanced nano/micro-suspension production technology.This research aims to establish a pilot-scale production line employing high-...The clinical application of solid lipid particles(SLPs)is hampered due to the need for advanced nano/micro-suspension production technology.This research aims to establish a pilot-scale production line employing high-speed shears as emulsification equipment.The primary purpose is to manufacture nano/micro-suspensions using solid lipid particles(SLPs).The study also exhaustively introduces and analyzes the regulatory schemes for process parameters and formulations at various stages of production.The process and formulation endured optimization through orthog-onal or single-factor tests at various production steps:laboratory research,small-scale trial production,and pilot production.Quality standards for the product were determined,and key parameters were obtained at each stage.The laboratory research demonstrated that the optimal SLPs comprised 15 mL 3%polyvinyl alcohol(PVA)per 1.0 g tilmicosin and 2.5 g carnauba wax(WAX).During small-scale production,modifications were made to the volume of the aqueous phase,emulsifier concentration,and emulsification strength,setting them to 16 mL,5%,and 2200 r/min,respectively.In the pilot production stage,the shear time was considered optimal at eight min.The impurity,content,polydispersion coefficient(PDI),and size of the pilot product were<3%,5%,0385 and 2.64μm,respectively.Among the several parameters studied,heating temperature,drug-lipid ratio,and emulsifier concentration were identified as the main factors affecting product quality,and they were regulated at 100℃,1:3,and 5%,respectively.A novel hot melt emulsification shear method aided the development of a new solid lipid-based suspension from its preliminary stages in the laboratory to pilot production.This innovation is expected to enhance solid lipid-based suspensions'industrial evolution extensively.展开更多
Objective Blood culture remains the gold standard for diagnosing bloodstream infections.Clinical laboratories must ensure the quality of blood culture processes from receipt to obtaining definitive results.We examined...Objective Blood culture remains the gold standard for diagnosing bloodstream infections.Clinical laboratories must ensure the quality of blood culture processes from receipt to obtaining definitive results.We examined laboratory analytical indicators associated with positive blood culture results.Methods Blood cultures collected from Peking Union Medical College Hospital between January 1,2020,and December 31,2022,were retrospectively analyzed.The mode of transportation(piping logistics delivery vs.staff),source of blood cultures(outpatient/emergency department vs.inpatient department),rotation of personnel,and time of reception(8:00–19:59 vs.20:00–07:59)were compared between blood culture-positive and-negative results.Results Between 2020 and 2022,the total positive rate of blood culture was 8.07%.The positive rate of blood cultures in the outpatient/emergency department was significantly higher than that in the inpatient department(12.46%vs.5.83%;P<0.0001).The time-to-detection of blood cultures was significantly affected by the delivery mode and personnel rotation.The blood culture positive rate of the total pre-analytical time within 1 h was significantly higher than that within 1–2 h or>2 h(P<0.0170).Conclusion Laboratory analytical indicators such as patient source,transportation mode,and personnel rotation significantly impacted the positive detection rate or time of blood culture.展开更多
Objective:To explore the application effect of the case-based problem-based learning(PBL)teaching model in clinical microbiology laboratory internship teaching,and provide a reference for the reform of clinical practi...Objective:To explore the application effect of the case-based problem-based learning(PBL)teaching model in clinical microbiology laboratory internship teaching,and provide a reference for the reform of clinical practical teaching.Methods:A total of 36 students who interned in the Clinical Laboratory of the Affiliated Hospital of Youjiang Medical University for Nationalities from May 2023 to April 2025 were selected as the research subjects.They were divided into two groups by the envelope method,with 18 students in each group.The control group adopted the traditional lecture-based teaching model,while the study group used the case-based PBL teaching model.The teaching scores,teaching quality,and satisfaction of the two groups of interns were compared.Results:The theoretical score(65.28±2.78),skill score(26.06±2.34),and total score(91.33±3.54)of the study group were all higher than those of the control group(61.67±3.01,22.28±2.49,83.94±3.72,respectively),and the differences were statistically significant(P<0.05).The results of the questionnaire showed that the scores of students in the study group in terms of autonomous learning,clinical thinking ability,comprehension ability,and learning interest were significantly higher than those in the control group,and all the differences were statistically significant(P<0.05).Meanwhile,the satisfaction rate of students in the study group with the teaching was significantly higher than that in the control group,and the difference was statistically significant(P<0.05).Conclusion:The PBL teaching model can effectively improve the academic performance of interns and the quality of teaching,enhance teaching satisfaction,and thus serve as a powerful auxiliary teaching method in clinical internship education.展开更多
In this study,the design and development of a sensor made of low-cost parts to monitor inclination and acceleration are presented.Αmicro electro-mechanical systems,micro electro mechanical systems,sensor was housed i...In this study,the design and development of a sensor made of low-cost parts to monitor inclination and acceleration are presented.Αmicro electro-mechanical systems,micro electro mechanical systems,sensor was housed in a robust enclosure and interfaced with a Raspberry Pi microcomputer with Internet connectivity into a proposed tilt and acceleration monitoring node.Online capabilities accessible by mobile phone such as real-time graph,early warning notification,and database logging were implemented using Python programming.The sensor response was calibrated for inherent bias and errors,and then tested thoroughly in the laboratory under static and dynamic loading conditions beside high-quality transducers.Satisfactory accuracy was achieved in real time using the Complementary Filter method,and it was further improved in LabVIEW using Kalman Filters with parameter tuning.A sensor interface with LabVIEW and a 600 MHz CPU microcontroller allowed real-time implementation of highspeed embedded filters,further optimizing sensor results.Kalman and embedded filtering results show agreement for the sensor,followed closely by the lowcomplexity complementary filter applied in real time.The sensor's dynamic response was also verified by shaking table tests,simulating past recorded seismic excitations or artificial vibrations,indicating negligible effect of external acceleration on measured tilt;sensor measurements were benchmarked using highquality tilt and acceleration measuring transducers.A preliminary field evaluation shows robustness of the sensor to harsh weather conditions.展开更多
This study describes the design and performance of a laboratory-based tender X-ray spectrometer for X-ray absorption spectroscopy.The system enables effective absorption spectra to be measured within the 2.0-9.0 keV r...This study describes the design and performance of a laboratory-based tender X-ray spectrometer for X-ray absorption spectroscopy.The system enables effective absorption spectra to be measured within the 2.0-9.0 keV range using Rowland circle geometry;it covers the K edge of 3d transition metals,the L edge of lanthanides,and the M edge of actinides.The spectrometer is configured with a Rowland circle with a diameter of 500 mm and integrates a 250 W liquid metal jet X-ray source,spherical bent crystal analyzer,and energy-resolving silicon drift detector.The X-ray source is installed outside the vacuum chamber and remains fixed,while the analyzer crystals and detector are adjusted to change the Bragg angle,maintaining the Rowland condition.The energy resolution is 0.36-1.30 eV at 2.0-9.0 keV,and the monochromatic flux is approximately 5×10^(5) counts/s at 7040 eV.This study highlights the primary characteristics of the spectrometer and demon-strates its capabilities using selected experimental examples.The successful development of this spectrometer can facilitate research on actinide elements,which are often constrained in synchrotron radiation experiments owing to their radioactivity,thus fostering advancements in related nuclear energy fields.展开更多
Natural earthquakes and micro-seismicity resulting from hydraulic fracturing or other engineering practices display distinctively different spatial-temporal features,like mixed burst-and swarm-like features or predomi...Natural earthquakes and micro-seismicity resulting from hydraulic fracturing or other engineering practices display distinctively different spatial-temporal features,like mixed burst-and swarm-like features or predominantly swarm-like features.The mechanism(s)contributing to such observations can be diverse.We present the inspections on the dynamic formation process of the single swarm-like tree in laboratory acoustic emission(AE)catalogs.Such largest swarm-like trees can contain>97%AE events from the entire catalog within a test;and all catalogs under investigation display scale-invariance features.The formation of the largest swarm-like tree correlates with the rock fracture process analogue of the source pervasive process,where its AE releases exhibit significant spatial well-organization.Comparison to other laboratory catalogs under different laboratory settings helps us identify the spatial continuity of the rock fracture process as the primary factor in forming the largest swarm-like trees at laboratory scale.The stress transfer process is involved in the rock fracture process for the tests having pre-existing spatial discontinuity.Artificial perturbations on the spatial information induced by the stress transfer process further confirm that stress transfer also serves to shift the pure swarm-like catalog into a mixed burst-and swarm-like catalog.These laboratory observations may provide inspirational insights for understanding the field-scale mechanism(s)shaping the spatial-temporal energy release features.展开更多
A double-parabola monocapillary(DPM)was designed for laboratory x-ray sources,and its performance was evaluated through numerical simulations and experimental validation.A surface shape error model was developed to ch...A double-parabola monocapillary(DPM)was designed for laboratory x-ray sources,and its performance was evaluated through numerical simulations and experimental validation.A surface shape error model was developed to characterize the DPM surface profile,and ray-tracing methods were used to simulate key properties such as focal spot size,divergence,and transmission efficiency.The simulation results closely matched experimental measurements,validating the proposed model.This surface shape error simulation provides an efficient method for evaluating the impact of slope errors on DPM performance,offering insights for optimal design and precision manufacturing.展开更多
Background:Medical laboratory diagnostic services play a critical role in the diagnosis,treatment,and manage-ment of diseases,forming the cornerstone of effective healthcare systems.Despite the crucial role of laborat...Background:Medical laboratory diagnostic services play a critical role in the diagnosis,treatment,and manage-ment of diseases,forming the cornerstone of effective healthcare systems.Despite the crucial role of laboratory services,the quality and accessibility of medical laboratory services in sub-Saharan Africa(SSA)face signifi-cant challenges.Global health development aid has been pivotal in supporting SSA laboratory services.This study aimed to examine global health development aid initiatives that have successfully enhanced the quality of medical laboratory services and the challenges and barriers to effectively improving medical laboratory services through global health development aid in SSA.Methods:We used a narrative review study design.We searched PubMed,Web of Science and Scopus for articles published in the last 15 years.These three databases are generally considered premier databases for peer-reviewed articles in global health,public health,health systems,and biomedical sciences.The inclusion criteria for this review included research studies,reports,and grey literature.Only articles published in English from 2010 on-ward were considered.The analysis followed a qualitative approach,emphasizing thematic synthesis and critical interpretation.Results:Forty articles were included in this study.Of these,18 were primary research studies,11 were reports,7 were commentaries,and 4 were reviews.Five sub-themes from the successful global health development aid initiative themes were capacity building and training programs,infrastructure development,partnership models,policy advocacy and regulatory support,quality control and standardization of laboratory services.The sub-themes from the challenges and barrier theme were insufficient funding and resource allocation,human resource constraints,inadequate infrastructure and equipment,and political and institutional barriers.This review re-vealed that several factors,including financial sustainability,human resource capacity,institutional support,resilience,and effective monitoring systems,shape the sustainability of improvements in medical laboratory services in SSA.Conclusion:Achieving long-term sustainability requires strategies that ensure financial self-sufficiency,foster a skilled and stable workforce,and integrate laboratory services into national health frameworks.展开更多
Remembrance activities can support the Culture of Care(CoC)in Laboratory Animal Science(LAS)not only by promoting a culture of respect,gratitude and thankfulness for animal life but also by helping the emotional proce...Remembrance activities can support the Culture of Care(CoC)in Laboratory Animal Science(LAS)not only by promoting a culture of respect,gratitude and thankfulness for animal life but also by helping the emotional processing and healing of lab animal researchers and animal facility staff.Even though remembrance activities are practiced in many parts of the world,we did not come across any reported cases in Sri Lanka before 2022.Therefore,here,we report on the various remembrance activities and practices observed within our local scientific community.展开更多
The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ...The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ultimate strength.In this study,both the acoustic emission method(AEM)and the ultrasonic testing method(UTM)were used to examine the characteristics of AE parameters(b-value,peak frequency,frequency-band energy ratio,and fractal dimension)and ultrasonic(ULT)properties(velocity,amplitude,energy attenuation,and scattering attenuation)of bedded shale at CI,CD,and ultimate strength.The comparison involved analyzing the strain-based method(SBM),AEM,and UTM to determine the thresholds for damage stress.A fuzzy comprehensive evaluation model(FCEM)was created to describe the damage thresholds and hazard assessment.The results indicate that the optimal AE and ULT parameters for identifying CI and CD stress are ringing count,ultrasonic amplitude,energy attenuation,and scattering attenuation of the S-wave.Besides,damage thresholds were detected earlier by AE monitoring,ranging from 3 MPa to 10 MPa.CI and CD identified by UTM occurred later than SBM and AEM,and were in the range of 12 MPa.The b-value,peak frequency,energy ratio in the low-frequency band(0e62.5 kHz),correlation dimension,and sandbox dimension showed low values at the peak stress,while the energy ratio in a moderate-frequency band(187.5e281.25 kHz)and amplitude showed high values.The successful application of FCEM to laboratory testing of shales has demonstrated its ability to quantitatively identify AE/ULT precursors of seismic hazards associated with rock failure.展开更多
Obtaining high-quality 10000-meter-deep seafloor sediment samples is the prerequisite and foundation for conducting deep-sea geological and environmental scientific research.The bottom structure of the deep seafloor i...Obtaining high-quality 10000-meter-deep seafloor sediment samples is the prerequisite and foundation for conducting deep-sea geological and environmental scientific research.The bottom structure of the deep seafloor is complex,and the physical and mechanical properties and disturbance resistance of sediments of different lithologies vary greatly,so the sediment sampler inevitably disturbs the sediments during the sampling process and affects the quality of the sediment samples.A new type of deep-sea sediment pressure retaining sampler is introduced,the force state and elastic–plastic state of the sampler destroying sediments are analyzed,the radial disturbance model of sediment coring based on the spherical cavity expansion theory is established,and the radius of sediments undergoing plastic deformation around the spherical holes is used as an index for evaluating the radial disturbance of sediments.The distribution of stress and strain fields in the sediments during the expansion of the spherical cavity and the influencing factors of the radius of the radially disturbed region(plastic region)are analyzed using an arithmetic example,and the influence law is analyzed.A sediment disturbance experimental platform was built indoors to simulate the sediment coring process.The radial stress field and pore water pressure of the sediment during the coring process were monitored by sensors arranged inside the sediment,and the results of indoor tests verified the correctness of the perturbation theory model.The sampler was carried aboard the deep-sea manned submersible FENDOUZHE and conducted on-site tests at depths of 9298.4 and 9142.8 m in the Kuril-Kamchatka Trench.Pressure-preserved sediment samples were retrieved,with preservation rates of 94.21%and 92.02%,respectively,which are much higher than the current technical indicator of 80%of pressure-holding ratio for deep-sea sediments.The retrieved sediments have obvious stratification characteristics and little disturbance.展开更多
Medium-high maturity continental shale oil is one of the hydrocarbon resources with the most potential for successful development in China.Nevertheless,the unique geological conditions of a multi-lithologic superposit...Medium-high maturity continental shale oil is one of the hydrocarbon resources with the most potential for successful development in China.Nevertheless,the unique geological conditions of a multi-lithologic superposition shield the vertical propagation of hydraulic fractures and limit the longitudinal reconstruction in reservoirs,posing a great challenge for large-scale volumetric fracturing.Radial wellbore crosslayer fracturing,which transforms the interaction between the hydraulic fractures and lithologic interface into longitudinal multilayer competitive initiation,could provide a potential solution for this engineering challenge.To determine the longitudinal propagation behaviors of fractures guided by radial wellbores,true triaxial fracturing experiments were performed on multilayer shale-sandstone samples,with a focus on the injection pressure response,fracture morphology,and cross-layer pattern.The effects of the radial borehole length L,vertical stress difference K_(v),injection rate Q,and viscosity m of the fracturing fluid were analyzed.The results indicate that radial wellbores can greatly facilitate fracture initiation and cross-layer propagation.Unlike conventional hydraulic fracturing,there are two distinct fracture propagation patterns in radial wellbore fracturing:cross-layering and skip-layering.The fracture height guided by a radial wellbore is positively correlated with K_(v),Q,and m.Increasing these parameters causes a shift in the fracture initiation from a single root to an asynchronous root/toe end and can improve the cross-layer propagation capacity.Critical parameter thresholds exist for fracture propagation through and across interlayers under the guidance of radial boreholes.A parameter combination of critical cross-layering/skip-layering or alternating displacement/viscosity is recommended to simultaneously improve the fracture height and degree of lateral activation.The degree of correlation of different parameters with the vertical fracture height can be written as L>Q/m>K_(v).Increasing the radial wellbore length can effectively facilitate fracture cross-/skip-layer propagation and reduce the critical threshold of injection parameters,which is conducive to maximizing the stimulated reservoir volume.展开更多
基金China Power Construction Group research project,Grant/Award Number:DJ-HXGG-2023-16National Natural Science Foundation of China-Yalong River Joint Fund Key Project,Grant/Award Number:U1965204+1 种基金National Natural Science Foundation of China,Grant/Award Number:52109143Open Research Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin(China Institute of Water Resources and Hydropower Research),Grant/Award Number:IWHR-SKL-KF202305。
文摘The Jinping Underground Laboratory is the deepest and largest underground laboratory in the world,with a maximum buried depth of approximately 2400 m.The objective is to study the brittle-ductile transition of marble through a combination of experimental research and constitutive modeling.Triaxial compression and triaxial cyclic loading tests are initially conducted to explore the accumulation of pre-peak plastic strain and the deterioration of stiffness of the marble.Then,a specific constitutive model is developed to accurately reflect the pre-peak plastic hardening and post-peak strain softening behaviors based on the deformation and failure mechanism of the marble.The incremental constitutive relationship of the proposed model is subsequently derived in detail,and the model parameters are calibrated using data obtained from the test results.Finally,the effectiveness of the proposed model is assessed by comparing its results with the experimental results of the marble.The findings show that the proposed model accurately predicts the behavior of the marble,and its results are in good agreement with the test data.
基金supported by the National Natural Science Foundation of China(Grant No.52192622)the Natural Science Foundation of Sichuan Province,China(Grant No.2025ZNSFSC0371)the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project(Grant No.SKLGP2022Z018).
文摘Fluid seepage and associated heat transfer within the enhanced geothermal system(EGS)regulate the extraction of heat from hot,low-water-saturation thermal reservoirs,sometimes referred to as hot dry rock(HDR).To understand these complex heat recovery processes,we simulated long-term heat extraction in a surrogate HDR using a true triaxial apparatus.A circulation test was first implemented to analyze the connectivity between different wells.Suitable injection and production wells were then selected for the laboratory heat extraction tests in granite,which lasted 14.5 h.Under variable injection rate conditions,we systematically analyzed the time-varying curves of temperature and flow rate in the production wells and pressure in the injection wells.Our findings showed that the advantage channel was dominant in the flow distribution when several paths existed in EGS.Changes in fracture conductivity are attributed to injection pressure.These included an increase in fracture width and activation of a localized closed area of fracture.These two mechanisms influenced the production temperature,and this is consistent with the field data monitored at the Fenton Hill and Hijiori projects.Fluid leak-off was an important factor affecting the production flow rate.For a fracture with low hydraulic conductivity,a lower injection rate could effectively prevent excessive fluid leak-off.In addition,by comparing injection rates and fluid recovery rates,production wells in different phases or injection modes had different fluid recovery rates even when the injection rates were the same.
基金supported by the Fundamental Research Funds for the Central Universities(No.226-2025-00031).
文摘In 2024, the MOE Key Laboratory of Macromolecular Synthesis and Functionalization at Zhejiang University continued its impactful researches across five core areas. In controllable catalytic polymerization,organoboron catalysts were developed for CO_(2) copolymerization and novel photoresist materials. Studies in microstructure and rheology elucidated universal deformation modes in graphene-based 2D membranes and improved graphene fiber properties through shear alignment engineering, defect control, and enhanced interlayer entanglement. For separating functional polymers, Janus membranes and channels were created for multiphase separation, liquid-phase molecular layer-by-layer deposition technique was developed to fabricate aromatic polyamide nanofilms, and the harmonic amide bond density was established as a valuable parameter for polyamide structural analysis. In biomedical functional polymers, a sustainable carboxyl-ester transesterification strategy was proposed for upcycling poly(ethylene terephthalate)(PET) waste into biodegradable plastics. Additionally, immunocompatible biomaterials were designed utilizing zwitterionic polypeptides and albumin-derived coatings, and Cu2+-phenolic nanoflower was designed to combat fungal infections by combining cuproptosis and cell wall digestion. Further,the researchers developed a gelatin-DOPA-knob/fibrinogen hydrogel to achieve rapid and robust hemostatic sealing, utilized a double-network polyelectrolyte-coated hydrogel for enhancing endothelialization of left atrial appendage(LAA) occluders, and the researchers also demonstrated that image-guided highintensity focused ultrasound enables manipulation of shape-memory polymers. Finally, in the realm of photo-electro-magnetic functional polymers, precise control of through-space conjugation was shown to enhance organic luminescence. Topologically structured hydrogels were revealed to exhibit autonomous actuation. Also, solar-driven photothermal ion pumps were developed for selective lithium extraction from seawater, and high-performance non-solvated C60single-crystal films were prepared via facile bar coating. Lastly, the researchers demonstrated outstanding dielectric properties of polyethylene(PE) lamellar single crystals. The relevant works are reviewed in this paper.
基金supported by the National Key Research and Development Project of the National Natural Science Foundation of China(Grant No.2022YFC3004605)the National Natural Science Foundation of China Youth Science Fund(Grant No.52104087).
文摘To advance the theoretical understanding,technological development,and field application of electric charge induction for monitoring rock deformation and failure,this study investigates the induced electric charge generated during the deformation and failure of igneous rocks.The charge originates mainly from a combination of electrical polarization and triboelectric effects.Through laboratory experiments,we analyzed the time-frequency evolution of induced electric charge signals and identified relevant monitoring parameters.An online downhole electric charge induction monitoring system was developed and validated in the field.Experimental results show that the dominant frequency range of induced electric charge signals generated during igneous rock deformation and failure lies between 0 and 23 Hz,and a low-pass finite impulse response(FIR)filter effectively suppresses noise.Optimal sensor distances for monitoring cubic and cylindrical specimens were determined to be 17 mm and 13 mm,respectively.We proposed early warning indicators,including the maximum absolute value of the induced electric charge,the arithmetic mean value,the distribution dispersion coefficient,and the cumulative sum value.In field application,time-domain curves and spatial distribution charts of these warning indicators correspond well with changes in abutment stress ahead of the mining face,offering indirect insights into local stress evolution.This research provides technical and equipment support for the application of electric charge induction technology to monitoring and early warning of coal bursts.
基金Open Access funding enabled and organized by Projekt DEAL.
文摘In this study,copper extraction from low-grade oxide-sulfide ores was investigated using a leaching method combined with response surface methodology(RSM)to optimize operational conditions and assess leaching kinetics.Given copper's extensive industrial applications,sustainable recovery from low-grade ores is critical.Five key parameters-acid concentration,leaching time,particle size,temperature,and solids percentage-were identified as major influences on copper recovery.The results revealed that leaching time and solids percentage,along with interactions between temperature-time and temperature-solids percentage,had the most significant effects.Optimal conditions for 80% copper recovery while minimizing iron recovery below 3% included an acid concentration of 1.21 mol L^(-1),a leaching time of 108 min,a particle size of 438μm,a temperature of 45℃,and a solids percentage of 18.2%.Leaching kinetics were analyzed using shrinking core models,with the Dickinson model best describing the process,showing an activation energy of 32.63 kJ mol^(-1),indicative of mixed diffusion and chemical reaction control.The final kinetic model effectively predicted the influence of key parameters.These findings highlight the importance of optimizing process variables and selecting suitable kinetic models to enhance extraction efficiency,reduce costs,and improve sustainability in copper recovery.
基金supported by Guizhou Provincial Higher Education Science and Technological Innovation Team,No.[2023]072 (to LX)Graduate Education and Teaching Innovation Program of Zunyi Medical University,No.ZYK262 (to QW)the Guizhou Graduate Research Fund,No.2024YJSKYJJ333 (to QW)
文摘Investigating the mechanisms underlying central nervous system disorders is a major scientific issue in the 21st century.However,the inaccessibility and complexity of the human brain have always represented a challenge in understanding the pathophysiology of the central nervous system.Brain organoids are self-assembled threedimensional aggregates derived from pluripotent stem cells with cell types and structures similar to the embryonic human brain,giving them potential for investigating the atypical cellular,molecular,and genetic characteristics characteristic of central nervous system disorders.Brain organoids also provide a platform for drug screening and serve as a potential source for transplantation therapy for brain injuries.However,the broad application of brain organoids is hampered by several limitations,such as the lack of high-fidelity cell types,insufficient maturation,and considerable heterogeneity,undermining their reliability in specific applications.This review summarizes brain organoid evolution,discusses recent technological and methodological innovations,and reviews their applications in drug screening,transplantation therapy,and disease modeling,as well as clinical research progress.Additionally,we emphasize the limitations of current brain organoid research and explore the potential for advancing the technology to enhance its applicability.
文摘Editorial message Every advancement in the field of laboratory animal science and technology,from exploring basic mechanisms to validating the development of new drugs,and from establishing disease models to responding to public health emergencies,strengthens the foundation for human health and well-being,serving as an important cornerstone for promoting global scientific innovation.For this reason.
基金supported by the National Natural Science Foundation of China(Nos.42107211 and U23A20651)the Natural Science Foundation of Sichuan Province(No.2025ZNSFSC0097)。
文摘Layered rock masses represent complex geological formations commonly encountered in the surrounding rock of deep engineering excavations(Hou et al.,2019;Xu et al.,2017;Yang C H et al.,2009;Xian and Tan,1989).These rock masses are predominantly composed of sedimentary,para-metamorphic,and volcanic rock types,characterized by a set of prominent,primary bedding structural planes(layers)exhibiting relatively consistent orientations and significant spatial continuity.
基金supported by the Fundamental Research Funds for the Central Universities(2662020DKPY008)the National Natural Science Foundation of China(grant No.31772797)。
文摘The clinical application of solid lipid particles(SLPs)is hampered due to the need for advanced nano/micro-suspension production technology.This research aims to establish a pilot-scale production line employing high-speed shears as emulsification equipment.The primary purpose is to manufacture nano/micro-suspensions using solid lipid particles(SLPs).The study also exhaustively introduces and analyzes the regulatory schemes for process parameters and formulations at various stages of production.The process and formulation endured optimization through orthog-onal or single-factor tests at various production steps:laboratory research,small-scale trial production,and pilot production.Quality standards for the product were determined,and key parameters were obtained at each stage.The laboratory research demonstrated that the optimal SLPs comprised 15 mL 3%polyvinyl alcohol(PVA)per 1.0 g tilmicosin and 2.5 g carnauba wax(WAX).During small-scale production,modifications were made to the volume of the aqueous phase,emulsifier concentration,and emulsification strength,setting them to 16 mL,5%,and 2200 r/min,respectively.In the pilot production stage,the shear time was considered optimal at eight min.The impurity,content,polydispersion coefficient(PDI),and size of the pilot product were<3%,5%,0385 and 2.64μm,respectively.Among the several parameters studied,heating temperature,drug-lipid ratio,and emulsifier concentration were identified as the main factors affecting product quality,and they were regulated at 100℃,1:3,and 5%,respectively.A novel hot melt emulsification shear method aided the development of a new solid lipid-based suspension from its preliminary stages in the laboratory to pilot production.This innovation is expected to enhance solid lipid-based suspensions'industrial evolution extensively.
基金supported by grants from the National High Level Hospital Clinical Research Funding(2022-PUMCH-B-074)Peking Union Medical College Hospital Research Funding for Postdoc(kyfyjj202320).
文摘Objective Blood culture remains the gold standard for diagnosing bloodstream infections.Clinical laboratories must ensure the quality of blood culture processes from receipt to obtaining definitive results.We examined laboratory analytical indicators associated with positive blood culture results.Methods Blood cultures collected from Peking Union Medical College Hospital between January 1,2020,and December 31,2022,were retrospectively analyzed.The mode of transportation(piping logistics delivery vs.staff),source of blood cultures(outpatient/emergency department vs.inpatient department),rotation of personnel,and time of reception(8:00–19:59 vs.20:00–07:59)were compared between blood culture-positive and-negative results.Results Between 2020 and 2022,the total positive rate of blood culture was 8.07%.The positive rate of blood cultures in the outpatient/emergency department was significantly higher than that in the inpatient department(12.46%vs.5.83%;P<0.0001).The time-to-detection of blood cultures was significantly affected by the delivery mode and personnel rotation.The blood culture positive rate of the total pre-analytical time within 1 h was significantly higher than that within 1–2 h or>2 h(P<0.0170).Conclusion Laboratory analytical indicators such as patient source,transportation mode,and personnel rotation significantly impacted the positive detection rate or time of blood culture.
基金This work was supported by the Reform Project of Degree and Postgraduate Education in Guangxi(JGY2025350)the Reform Project of Youjiang Medical University for Nationalities(J2024-04).
文摘Objective:To explore the application effect of the case-based problem-based learning(PBL)teaching model in clinical microbiology laboratory internship teaching,and provide a reference for the reform of clinical practical teaching.Methods:A total of 36 students who interned in the Clinical Laboratory of the Affiliated Hospital of Youjiang Medical University for Nationalities from May 2023 to April 2025 were selected as the research subjects.They were divided into two groups by the envelope method,with 18 students in each group.The control group adopted the traditional lecture-based teaching model,while the study group used the case-based PBL teaching model.The teaching scores,teaching quality,and satisfaction of the two groups of interns were compared.Results:The theoretical score(65.28±2.78),skill score(26.06±2.34),and total score(91.33±3.54)of the study group were all higher than those of the control group(61.67±3.01,22.28±2.49,83.94±3.72,respectively),and the differences were statistically significant(P<0.05).The results of the questionnaire showed that the scores of students in the study group in terms of autonomous learning,clinical thinking ability,comprehension ability,and learning interest were significantly higher than those in the control group,and all the differences were statistically significant(P<0.05).Meanwhile,the satisfaction rate of students in the study group with the teaching was significantly higher than that in the control group,and the difference was statistically significant(P<0.05).Conclusion:The PBL teaching model can effectively improve the academic performance of interns and the quality of teaching,enhance teaching satisfaction,and thus serve as a powerful auxiliary teaching method in clinical internship education.
基金Research Committee,National Technical University of Athens。
文摘In this study,the design and development of a sensor made of low-cost parts to monitor inclination and acceleration are presented.Αmicro electro-mechanical systems,micro electro mechanical systems,sensor was housed in a robust enclosure and interfaced with a Raspberry Pi microcomputer with Internet connectivity into a proposed tilt and acceleration monitoring node.Online capabilities accessible by mobile phone such as real-time graph,early warning notification,and database logging were implemented using Python programming.The sensor response was calibrated for inherent bias and errors,and then tested thoroughly in the laboratory under static and dynamic loading conditions beside high-quality transducers.Satisfactory accuracy was achieved in real time using the Complementary Filter method,and it was further improved in LabVIEW using Kalman Filters with parameter tuning.A sensor interface with LabVIEW and a 600 MHz CPU microcontroller allowed real-time implementation of highspeed embedded filters,further optimizing sensor results.Kalman and embedded filtering results show agreement for the sensor,followed closely by the lowcomplexity complementary filter applied in real time.The sensor's dynamic response was also verified by shaking table tests,simulating past recorded seismic excitations or artificial vibrations,indicating negligible effect of external acceleration on measured tilt;sensor measurements were benchmarked using highquality tilt and acceleration measuring transducers.A preliminary field evaluation shows robustness of the sensor to harsh weather conditions.
基金supported by the Instrument and Equipment Development Program of the Chinese Academy of Science(Grant No.YJKYYQ20180066)the National Natural Science Foundation of China(No.22227809)+2 种基金the Shanghai Science and Technology Innovation Action Plan(No.22142200300)the Science and Technology Talents Program of the Shanghai Institute of Applied Physics(No.SINAP-KJZX-202204)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA 0400000).
文摘This study describes the design and performance of a laboratory-based tender X-ray spectrometer for X-ray absorption spectroscopy.The system enables effective absorption spectra to be measured within the 2.0-9.0 keV range using Rowland circle geometry;it covers the K edge of 3d transition metals,the L edge of lanthanides,and the M edge of actinides.The spectrometer is configured with a Rowland circle with a diameter of 500 mm and integrates a 250 W liquid metal jet X-ray source,spherical bent crystal analyzer,and energy-resolving silicon drift detector.The X-ray source is installed outside the vacuum chamber and remains fixed,while the analyzer crystals and detector are adjusted to change the Bragg angle,maintaining the Rowland condition.The energy resolution is 0.36-1.30 eV at 2.0-9.0 keV,and the monochromatic flux is approximately 5×10^(5) counts/s at 7040 eV.This study highlights the primary characteristics of the spectrometer and demon-strates its capabilities using selected experimental examples.The successful development of this spectrometer can facilitate research on actinide elements,which are often constrained in synchrotron radiation experiments owing to their radioactivity,thus fostering advancements in related nuclear energy fields.
文摘Natural earthquakes and micro-seismicity resulting from hydraulic fracturing or other engineering practices display distinctively different spatial-temporal features,like mixed burst-and swarm-like features or predominantly swarm-like features.The mechanism(s)contributing to such observations can be diverse.We present the inspections on the dynamic formation process of the single swarm-like tree in laboratory acoustic emission(AE)catalogs.Such largest swarm-like trees can contain>97%AE events from the entire catalog within a test;and all catalogs under investigation display scale-invariance features.The formation of the largest swarm-like tree correlates with the rock fracture process analogue of the source pervasive process,where its AE releases exhibit significant spatial well-organization.Comparison to other laboratory catalogs under different laboratory settings helps us identify the spatial continuity of the rock fracture process as the primary factor in forming the largest swarm-like trees at laboratory scale.The stress transfer process is involved in the rock fracture process for the tests having pre-existing spatial discontinuity.Artificial perturbations on the spatial information induced by the stress transfer process further confirm that stress transfer also serves to shift the pure swarm-like catalog into a mixed burst-and swarm-like catalog.These laboratory observations may provide inspirational insights for understanding the field-scale mechanism(s)shaping the spatial-temporal energy release features.
基金supported by project of Beijing Postdoctoral Research Fund(Grant No.2025-ZZ-86)the National Natural Science Foundation of China(Grant Nos.12105020 and 12075031)+3 种基金Shenzhen Science and Technology Program(Grant No.KJZD20230923114219040)the Natural Science Youth Foundation of Henan Province,China(Grant No.242300420637)the Open Fund of Key Laboratory of Beam Technology of the Ministry of Education,Beijing Normal University(Grant No.BEAM2024G02)the Innovation Cultivation of Beijing Academy of Science and Technology(Grant Nos.25CB007-01 and 25CB007-02)。
文摘A double-parabola monocapillary(DPM)was designed for laboratory x-ray sources,and its performance was evaluated through numerical simulations and experimental validation.A surface shape error model was developed to characterize the DPM surface profile,and ray-tracing methods were used to simulate key properties such as focal spot size,divergence,and transmission efficiency.The simulation results closely matched experimental measurements,validating the proposed model.This surface shape error simulation provides an efficient method for evaluating the impact of slope errors on DPM performance,offering insights for optimal design and precision manufacturing.
文摘Background:Medical laboratory diagnostic services play a critical role in the diagnosis,treatment,and manage-ment of diseases,forming the cornerstone of effective healthcare systems.Despite the crucial role of laboratory services,the quality and accessibility of medical laboratory services in sub-Saharan Africa(SSA)face signifi-cant challenges.Global health development aid has been pivotal in supporting SSA laboratory services.This study aimed to examine global health development aid initiatives that have successfully enhanced the quality of medical laboratory services and the challenges and barriers to effectively improving medical laboratory services through global health development aid in SSA.Methods:We used a narrative review study design.We searched PubMed,Web of Science and Scopus for articles published in the last 15 years.These three databases are generally considered premier databases for peer-reviewed articles in global health,public health,health systems,and biomedical sciences.The inclusion criteria for this review included research studies,reports,and grey literature.Only articles published in English from 2010 on-ward were considered.The analysis followed a qualitative approach,emphasizing thematic synthesis and critical interpretation.Results:Forty articles were included in this study.Of these,18 were primary research studies,11 were reports,7 were commentaries,and 4 were reviews.Five sub-themes from the successful global health development aid initiative themes were capacity building and training programs,infrastructure development,partnership models,policy advocacy and regulatory support,quality control and standardization of laboratory services.The sub-themes from the challenges and barrier theme were insufficient funding and resource allocation,human resource constraints,inadequate infrastructure and equipment,and political and institutional barriers.This review re-vealed that several factors,including financial sustainability,human resource capacity,institutional support,resilience,and effective monitoring systems,shape the sustainability of improvements in medical laboratory services in SSA.Conclusion:Achieving long-term sustainability requires strategies that ensure financial self-sufficiency,foster a skilled and stable workforce,and integrate laboratory services into national health frameworks.
文摘Remembrance activities can support the Culture of Care(CoC)in Laboratory Animal Science(LAS)not only by promoting a culture of respect,gratitude and thankfulness for animal life but also by helping the emotional processing and healing of lab animal researchers and animal facility staff.Even though remembrance activities are practiced in many parts of the world,we did not come across any reported cases in Sri Lanka before 2022.Therefore,here,we report on the various remembrance activities and practices observed within our local scientific community.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U20A20266 and 12302503)Scientific and technological research projects in Sichuan province(Grant No.2024NSFSC0973).
文摘The loaded rock experiences multiple stages of deformation.It starts with the formation of microcracks at low stresses(crack initiation,CI)and then transitions into unstable crack propagation(crack damage,CD)near the ultimate strength.In this study,both the acoustic emission method(AEM)and the ultrasonic testing method(UTM)were used to examine the characteristics of AE parameters(b-value,peak frequency,frequency-band energy ratio,and fractal dimension)and ultrasonic(ULT)properties(velocity,amplitude,energy attenuation,and scattering attenuation)of bedded shale at CI,CD,and ultimate strength.The comparison involved analyzing the strain-based method(SBM),AEM,and UTM to determine the thresholds for damage stress.A fuzzy comprehensive evaluation model(FCEM)was created to describe the damage thresholds and hazard assessment.The results indicate that the optimal AE and ULT parameters for identifying CI and CD stress are ringing count,ultrasonic amplitude,energy attenuation,and scattering attenuation of the S-wave.Besides,damage thresholds were detected earlier by AE monitoring,ranging from 3 MPa to 10 MPa.CI and CD identified by UTM occurred later than SBM and AEM,and were in the range of 12 MPa.The b-value,peak frequency,energy ratio in the low-frequency band(0e62.5 kHz),correlation dimension,and sandbox dimension showed low values at the peak stress,while the energy ratio in a moderate-frequency band(187.5e281.25 kHz)and amplitude showed high values.The successful application of FCEM to laboratory testing of shales has demonstrated its ability to quantitatively identify AE/ULT precursors of seismic hazards associated with rock failure.
基金supported by the National Key Research and Development Program of China(Nos.2023YFC2809304 and 2022YFC2805904).
文摘Obtaining high-quality 10000-meter-deep seafloor sediment samples is the prerequisite and foundation for conducting deep-sea geological and environmental scientific research.The bottom structure of the deep seafloor is complex,and the physical and mechanical properties and disturbance resistance of sediments of different lithologies vary greatly,so the sediment sampler inevitably disturbs the sediments during the sampling process and affects the quality of the sediment samples.A new type of deep-sea sediment pressure retaining sampler is introduced,the force state and elastic–plastic state of the sampler destroying sediments are analyzed,the radial disturbance model of sediment coring based on the spherical cavity expansion theory is established,and the radius of sediments undergoing plastic deformation around the spherical holes is used as an index for evaluating the radial disturbance of sediments.The distribution of stress and strain fields in the sediments during the expansion of the spherical cavity and the influencing factors of the radius of the radially disturbed region(plastic region)are analyzed using an arithmetic example,and the influence law is analyzed.A sediment disturbance experimental platform was built indoors to simulate the sediment coring process.The radial stress field and pore water pressure of the sediment during the coring process were monitored by sensors arranged inside the sediment,and the results of indoor tests verified the correctness of the perturbation theory model.The sampler was carried aboard the deep-sea manned submersible FENDOUZHE and conducted on-site tests at depths of 9298.4 and 9142.8 m in the Kuril-Kamchatka Trench.Pressure-preserved sediment samples were retrieved,with preservation rates of 94.21%and 92.02%,respectively,which are much higher than the current technical indicator of 80%of pressure-holding ratio for deep-sea sediments.The retrieved sediments have obvious stratification characteristics and little disturbance.
基金supported by the National Natural Science Foun-dation of China(52421002,U24B6001,52204019,and 52192624)the Open Foundation of the Shanxi Key Laboratory of Carbon Dioxide Sequestration and Enhanced Oil Recovery。
文摘Medium-high maturity continental shale oil is one of the hydrocarbon resources with the most potential for successful development in China.Nevertheless,the unique geological conditions of a multi-lithologic superposition shield the vertical propagation of hydraulic fractures and limit the longitudinal reconstruction in reservoirs,posing a great challenge for large-scale volumetric fracturing.Radial wellbore crosslayer fracturing,which transforms the interaction between the hydraulic fractures and lithologic interface into longitudinal multilayer competitive initiation,could provide a potential solution for this engineering challenge.To determine the longitudinal propagation behaviors of fractures guided by radial wellbores,true triaxial fracturing experiments were performed on multilayer shale-sandstone samples,with a focus on the injection pressure response,fracture morphology,and cross-layer pattern.The effects of the radial borehole length L,vertical stress difference K_(v),injection rate Q,and viscosity m of the fracturing fluid were analyzed.The results indicate that radial wellbores can greatly facilitate fracture initiation and cross-layer propagation.Unlike conventional hydraulic fracturing,there are two distinct fracture propagation patterns in radial wellbore fracturing:cross-layering and skip-layering.The fracture height guided by a radial wellbore is positively correlated with K_(v),Q,and m.Increasing these parameters causes a shift in the fracture initiation from a single root to an asynchronous root/toe end and can improve the cross-layer propagation capacity.Critical parameter thresholds exist for fracture propagation through and across interlayers under the guidance of radial boreholes.A parameter combination of critical cross-layering/skip-layering or alternating displacement/viscosity is recommended to simultaneously improve the fracture height and degree of lateral activation.The degree of correlation of different parameters with the vertical fracture height can be written as L>Q/m>K_(v).Increasing the radial wellbore length can effectively facilitate fracture cross-/skip-layer propagation and reduce the critical threshold of injection parameters,which is conducive to maximizing the stimulated reservoir volume.
