At present,there is limited research on the application of fuel cell power generation system technology using solid hydrogen storage materials,especially in hydrogen-assisted two-wheelers.Considering the disadvantages...At present,there is limited research on the application of fuel cell power generation system technology using solid hydrogen storage materials,especially in hydrogen-assisted two-wheelers.Considering the disadvantages of low hydrogen storage capacity and poor kinetics of hydrogen storage materials,our primary focus is to achieve smooth hydrogen ab-/desorption over a wide temperature range to meet the requirements of fuel cells and their integrated power generation systems.In this paper,the Ti_(0.9)Zr_(0.1)Mn_(1.45)V_(0.4)Fe_(0.15) hydrogen storage alloy was successfully prepared by arc melting.The maximum hydrogen storage capacity reaches 1.89 wt% at 318 K.The alloy has the capability to absorb 90% of hydrogen storage capacity within 50 s at 7 MPa and release 90% of hydrogen within 220 s.Comsol Multiphysics 6.0 software was used to simulate the hydrogen ab-/desorption processes of the tank.The flow rate of cooling water during hydrogen absorption varied in a gradient of(0.02 t x)m s^(-1)(x=0,0.02,0.04,0.06,0.08,0.1,0.12).Cooling water flow rate is positively correlated with the hydrogen absorption rate but negatively correlated with the cost.When the cooling rate is 0.06 m s^(-1),both simulation and experimentation have shown that the hydrogen storage tank is capable of steady hydrogen desorption for over 6 h at a flow rate of 2 L min^(-1).Based on the above conclusions,we have successfully developed a hydrogen-assisted two-wheeler with a range of 80 km and achieved regional demonstration operations in Changzhou and Shaoguan.This paper highlights the achievements of our team in the technological development of fuel cell power generation systems using solid hydrogen storage materials as hydrogen storage carriers and their application in twowheelers in recent years.展开更多
Through continuous equipment technology transformation and full utilization of Ma Steel's abundant gas,the boiler no longer relies on fuel oil for stable combustion during boiler startup,sliding parameter shutdown...Through continuous equipment technology transformation and full utilization of Ma Steel's abundant gas,the boiler no longer relies on fuel oil for stable combustion during boiler startup,sliding parameter shutdown,and RB,thus achieving safe and stable operation of the boiler under any abnormal working conditions,and achieving good economic and social benefits.展开更多
Background and objective Low-density computed tomography(LDCT)improved early lung cancer diagnosis but introduces an excess of false-positive pulmonary nodules data.Hence,accurate diagnosis of early-stage lung cancer ...Background and objective Low-density computed tomography(LDCT)improved early lung cancer diagnosis but introduces an excess of false-positive pulmonary nodules data.Hence,accurate diagnosis of early-stage lung cancer remains challenging.The purpose of the study was to assess the feasibility of using circulating tumour cells(CTCs)to differentiate malignant from benign pulmonary nodules.Materials and methods 122 patients with suspected malignant pulmonary nodules detected on chest CT in preparation for surgery were prospectively recruited.Peripheral blood samples were collected before surgery,and CTCs were identified upon isolation by size of epithelial tumour cells and morphological analysis.Laser capture microdissection,MALBAC amplification,and whole-exome sequencing were performed on 8 samples.The diagnostic efficacy of CTCs counting,and the genomic variation profile of benign and malignant CTCs samples were analysed.Results Using 2.5 cells/5 m L as the cut-off value,the area under the receiver operating characteristic curve was of 0.651(95%confidence interval:0.538-0.764),with a sensitivity and specificity of 0.526 and 0.800,respectively,and positive and negative predictive values of 91.1%and 30.3%,respectively.Distinct sequence variations differences in DNA damage repair-related and driver genes were observed in benign and malignant samples.TP53 mutations were identified in CTCs of four malignant cases;in particular,g.7578115T>C,g.7578645C>T,and g.7579472G>C were exclusively detected in all four malignant samples.Conclusion CTCs play an ancillary role in the diagnosis of pulmonary nodules.TP53 mutations in CTCs might be used to identify benign and malignant pulmonary nodules.展开更多
With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to r...With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to reservoir damage and wellbore instability.In this paper,micronized barite(MB)was modified(mMB)by grafting with hydrophilic polymer onto the surface through the free radical polymerization to displace conventional API barite partly.The suspension stability of water-based drilling fluids(WBDFs)weighted with API barite:mMB=2:1 in 600 g was significantly enhanced compared with that with API barite/WBDFs,exhibiting the static sag factor within 0.54 and the whole stability index of 2.The viscosity and yield point reached the minimum,with a reduction of more than 40%compared with API barite only at the same density.Through multi-stage filling and dense accumulation of weighting materials and clays,filtration loss was decreased,mud cake quality was improved,and simultaneously it had great reservoir protection performance,and the permeability recovery rate reached 87%.In addition,it also effectively improved the lubricity of WBDFs.The sticking coefficient of mud cake was reduced by 53.4%,and the friction coefficient was 0.2603.Therefore,mMB can serve as a versatile additive to control the density,rheology,filtration,and stability of WBDFs weighted with API barite,thus regulating comprehensive performance and achieving reservoir protection capacity.This work opened up a new path for the productive drilling of extremely deep and intricate wells by providing an efficient method for managing the performance of high-density WBDFs.展开更多
Deep shale reservoirs(3500–4500 m)exhibit significantly different stress states than moderately deep shale reservoirs(2000–3500 m).As a result,the brittleness response mechanisms of deep shales are also different.It...Deep shale reservoirs(3500–4500 m)exhibit significantly different stress states than moderately deep shale reservoirs(2000–3500 m).As a result,the brittleness response mechanisms of deep shales are also different.It is urgent to investigate methods to evaluate the brittleness of deep shales to meet the increasingly urgent needs of deep shale gas development.In this paper,the quotient of Young’s modulus divided by Poisson’s ratio based on triaxial compression tests under in situ stress conditions is taken as SSBV(Static Standard Brittleness Value).A new and pragmatic technique is developed to determine the static brittleness index that considers elastic parameters,the mineral content,and the in situ stress conditions(BIEMS).The coefficient of determination between BIEMS and SSBV reaches 0.555 for experimental data and 0.805 for field data.This coefficient is higher than that of other brittleness indices when compared to SSBV.BIEMS can offer detailed insights into shale brittleness under various conditions,including different mineral compositions,depths,and stress states.This technique can provide a solid data-based foundation for the selection of‘sweet spots’for single-well engineering and the comparison of the brittleness of shale gas production layers in different areas.展开更多
Cooperation among enterprises can bring overall and individual performance improvement,and a smooth coordination method is indispensable.However,due to the lack of customized coordination methods,cooperation in the do...Cooperation among enterprises can bring overall and individual performance improvement,and a smooth coordination method is indispensable.However,due to the lack of customized coordination methods,cooperation in the downstream oil supply chain cannot be carried out smoothly.This paper intends to propose a multi-party coordination method to promote cooperation between oil shippers and pipeline operator by optimizing oil transportation,oil substitution and pipeline pricing schemes.An integrated game-theoretic modeling and analysis approach is developed to characterize the operation behaviors of all stakeholders in the downstream oil supply chain.The proposed mixed integer nonlinear programming model constrains supply and demand capacity,transportation routes,oil substitution rules and pipeline freight levels.Logarithm transformation and price discretization are introduced for model linear approximation.Simulation experiments are carried out in the oil distribution system in South China.The results show that compared to the business-as-usual scheme,the new scheme saves transportation cost by 3.48%,increases pipeline turnover by 5.7%,and reduces energy consumption and emissions by 7.66%and 6.77%.It is proved that the proposed method improves the revenue of the whole system,achieves fair revenue distribution,and also improves the energy and environmental benefits of the oil supply chain.展开更多
Background:Apolipoprotein E4(ApoE4)allele is the strongest genetic risk factor for late-onset Alzheimer's disease,and it can aggravate depressive symptoms in non-AD patients.However,the impact of ApoE4 on AD-assoc...Background:Apolipoprotein E4(ApoE4)allele is the strongest genetic risk factor for late-onset Alzheimer's disease,and it can aggravate depressive symptoms in non-AD patients.However,the impact of ApoE4 on AD-associated depression-l ike behaviors and its underlying pathogenic mechanisms remain unclear.Methods:This study developed a 5xFAD mouse model overexpressing human ApoE4(E4FAD).Behavioral assessments and synaptic function tests were conducted to explore the effects of ApoE4 on cognition and depression in 5xFAD mice.Changes in peripheral and central lipid metabolism,as well as the levels of serotonin(5-HT)andγ-aminobutyric acid(GABA)neurotransmitters in the prefrontal cortex,were examined.In addition,the protein levels of 24-dehydrocholesterol reductase/glycogen synthase kinase-3 beta/mammalian target of rapamycin(DHCR24/GSK3β/m TOR)and postsynaptic density protein 95/calmodulin-dependent protein kinase II/brain-derived neurotrophic factor(PSD95/CaMK-II/BDNF)were measured to investigate the molecular mechanism underlying the effects of ApoE4 on AD mice.Results:Compared with 5xFAD mice,E4FAD mice exhibited more severe depressionlike behaviors and cognitive impairments.These mice also exhibited increased amyloid-beta deposition in the hippocampus,increased astrocyte numbers,and decreased expression of depression-related neurotransmitters 5-HT and GABA in the prefrontal cortex.Furthermore,lipid metabolism disorders were observed in E4FAD,manifesting as elevated low-density lipoprotein cholesterol and reduced high-density lipoprotein cholesterol in peripheral blood,decreased cholesterol level in the prefrontal cortex,and reduced expression of key enzymes and proteins related to cholesterol synthesis and homeostasis.Abnormal expression of proteins related to the DHCR24/GSK3β/m TOR and PSD95/CaMK-II/BDNF pathways was also observed.Conclusion:This study found that ApoE4 overexpression exacerbates depressionlike behaviors in 5xFAD mice and confirmed that ApoE4 reduces cognitive function in these mice.The mechanism may involve the induction of central and peripheral lipid metabolism disorders.Therefore,modulating ApoE expression or function to restore cellular lipid homeostasis may be a promising therapeutic target for AD comorbid with depression.This study also provided a better animal model for studying AD comorbid with depression.展开更多
Objective: To explore the clinical value of surgical treatment and postoperative anti-infection treatment for acute suppurative appendicitis. Methods: A total of 116 patients with acute suppurative appendicitis were e...Objective: To explore the clinical value of surgical treatment and postoperative anti-infection treatment for acute suppurative appendicitis. Methods: A total of 116 patients with acute suppurative appendicitis were enrolled in this study. The collection period was from December 2021 to December 2023. The patients were randomly grouped into a control group (surgical treatment) and an observation group (surgical treatment and postoperative anti-infection treatment), of 58 patients each. At the end of the treatment, the results of each index of the two groups were compared. Results: The length of hospitalization time, exhaust time, and incidence of complications in the observation group were shorter than those of the control group (P < 0.05). The total effective rate of the observation group was higher than that of the control group (P < 0.05). Conclusion: It is crucial to perform anti-infective treatment promptly after surgical treatment in patients with acute suppurative appendicitis. It can effectively prevent the occurrence of complications and improve the clinical efficacy. Hence, it is worthy of research and promotion.展开更多
Background: Augmented reality(AR) technology is used to reconstruct three-dimensional(3D) images of hepatic and biliary structures from computed tomography and magnetic resonance imaging data, and to superimpose the v...Background: Augmented reality(AR) technology is used to reconstruct three-dimensional(3D) images of hepatic and biliary structures from computed tomography and magnetic resonance imaging data, and to superimpose the virtual images onto a view of the surgical field. In liver surgery, these superimposed virtual images help the surgeon to visualize intrahepatic structures and therefore, to operate precisely and to improve clinical outcomes.Data Sources: The keywords "augmented reality", "liver", "laparoscopic" and "hepatectomy" were used for searching publications in the Pub Med database. The primary source of literatures was from peer-reviewed journals up to December 2016. Additional articles were identified by manual search of references found in the key articles.Results: In general, AR technology mainly includes 3D reconstruction, display, registration as well as tracking techniques and has recently been adopted gradually for liver surgeries including laparoscopy and laparotomy with video-based AR assisted laparoscopic resection as the main technical application. By applying AR technology, blood vessels and tumor structures in the liver can be displayed during surgery,which permits precise navigation during complex surgical procedures. Liver transformation and registration errors during surgery were the main factors that limit the application of AR technology.Conclusions: With recent advances, AR technologies have the potential to improve hepatobiliary surgical procedures. However, additional clinical studies will be required to evaluate AR as a tool for reducing postoperative morbidity and mortality and for the improvement of long-term clinical outcomes. Future research is needed in the fusion of multiple imaging modalities, improving biomechanical liver modeling,and enhancing image data processing and tracking technologies to increase the accuracy of current AR methods.展开更多
The epidemiology of highly pathogenic porcine reproductive and respiratory syndrome( HP-PRRS) in Changping District,Beijing City was investigated from 2010 to 2015. Through statistics of vaccine,immune procedure and a...The epidemiology of highly pathogenic porcine reproductive and respiratory syndrome( HP-PRRS) in Changping District,Beijing City was investigated from 2010 to 2015. Through statistics of vaccine,immune procedure and antibody levels,the epidemic prevention effect of HP-PRRS in Changping District was scientifically assessed.展开更多
The development of coalbed methane (CBM) in China poses great difficulties because of high investments, low produc- tion and high risks. So a study of the economic effect of a single well at its preliminary stage is h...The development of coalbed methane (CBM) in China poses great difficulties because of high investments, low produc- tion and high risks. So a study of the economic effect of a single well at its preliminary stage is helpful for commercial exploitation of CBM. Affected by wellbore flow pressure, initial reservoir pressure, relative permeability, Langmuir pressure and other factors, the trend of declining production of a single CBM well agrees, by and large, with a hyperbolic pattern of decline. Based on Arps’s equation, nearly 200 wells production with different peak yields and initial rates of were simulated. Given the present cost of drill- ing, gas production and engineering on the ground, the gross investment for the development of a single coalbed methane well was estimated for the Fanzhuang block in central China. Considering the current industrial policies for CBM, we established an eco- nomic assessment model and analyzed economic peaks. The results show the economic benefits with or without government subsi- dies at different peak yields of a single CBM well. The results of the evaluation can be directly applied in the Fanzhuang block. The evaluation method, formulated in our study, can be used to other areas with similar conditions.展开更多
Hierarchically porous architecture of ir on-nitroge n-carb on(Fe-N-C)for oxyge n reducti on reaction(ORR)is highly desired towards efficient mass transfer in the fuel cell device manner.Herein,we reported a binary lig...Hierarchically porous architecture of ir on-nitroge n-carb on(Fe-N-C)for oxyge n reducti on reaction(ORR)is highly desired towards efficient mass transfer in the fuel cell device manner.Herein,we reported a binary ligand strategy to prepare zeolitic imidazolate frameworks(ZIFs)-derived precursors,wherein the addition of secondary ligand endows precursors with the capabilities to transform into porously interweaved encapsulation-nanotubes structured composites after calcination.The optimal catalyst,i.e.,termed as Fe_(6)-M/C-3,exhibits excellent durability with 88.8%current retention after 50,000 seconds in 0.1 M HClO_(4)solution by virtue of nanoparticles-encapsulation features,which is more positive than the benchmark commercial 20 wt%Pt/C catalyst.Moreover,a promising maximum power density of Fe_(6)-M/C-3 as cathode catalyst was also dem on strated in proton exchange membrane fuel cells(PEMFCs)measurements.Therefore,this binary ligand approach to the fabrication of hierarchically porous structures would also have significant implications for various other electrochemical reactions.展开更多
Objective:To evaluate the detection of IgM and IgG antibodies to Orientia tsutsugamushi(O. tsutsugamushi) by rapid diagnostic test(RDT) and microimmunofluorescence assay(ml FA). Methods:RDT using a mixture of recombin...Objective:To evaluate the detection of IgM and IgG antibodies to Orientia tsutsugamushi(O. tsutsugamushi) by rapid diagnostic test(RDT) and microimmunofluorescence assay(ml FA). Methods:RDT using a mixture of recombinant 56-kDa proteins of O.tsutsugamushi and mIFA assay were performed on 20 patients from Fujian and 13 patients from Yunnan Province,and 82 sera samples from healthy farmers in Anhui Province and Beijing City in 2009.Comparison of the RDT and mIFA assay was performed by using X test and the P level of 【0.05 was considered to be significance.Results:Among these 82 normal sera samples,the specificity of RDT was 100%for both IgM and IgG tests.In 33 samples from patients with scrub typhus,5 cases were positively detected earlier by RDT than by mIFA in IgM test,and 2 cases were positive in IgG test.Sensitivities of RDT were 93.9%and 90.9%for IgM and IgG,respectively.The sensitivity of combination lest of IgM and IgG was 100%.Geometric mean titer diluted sera from confirmed cases by IFA and RDT assay were 1:37 vs.1:113(P【0.001) in IgM test and 1:99 vs.1:279 (P【0.05) in IgG test.Conclusions:RDT is more sensitivite than mIFA in the early diagnosis of scrub typhus and it is particularly applicable in rural areas.展开更多
The metamorphism and hydrocarbon generation from the Upper Paleozoic coal-bearing strata in Northern China have been widely studied by Chinese geologists since the 1990s. Based on a large amount of data of Ro values,c...The metamorphism and hydrocarbon generation from the Upper Paleozoic coal-bearing strata in Northern China have been widely studied by Chinese geologists since the 1990s. Based on a large amount of data of Ro values,combined with geological background,we have systematically analyzed the thermal evolutionary characteristics of or-ganic matter and the stages of hydrocarbon generation from the Permo-Carboniferous coal deposits and discussed the condition of secondary hydrocarbon generation. The distribution range of secondary hydrocarbon generation in North-ern China is thus determined. It is shown that the coal ranks of the Upper Paleozoic coal deposits are higher in the southern and western belts than those in the northern and eastern belts. Really significant secondary hydrocarbon gen-eration is mainly related to the thermal evolution of organic matter during the Himalayan Period. Profitable areas for secondary hydrocarbon generation should be buried at 3000-4000 m up to the present. Maturity of the Permo-Carbon-iferous source rocks is not very high. It is suggested that the Bohai Bay depression is favourable for secondary hydro-carbon generation and has good oil and gas prospects.展开更多
Spectral decomposition has been widely used in the detection and identifi cation of underground anomalous features(such as faults,river channels,and karst caves).However,the conventional spectral decomposition method ...Spectral decomposition has been widely used in the detection and identifi cation of underground anomalous features(such as faults,river channels,and karst caves).However,the conventional spectral decomposition method is restrained by the window function,and hence,it mostly has low time–frequency focusing and resolution,thereby hampering the fi ne interpretation of seismic targets.To solve this problem,we investigated the sparse inverse spectral decomposition constrained by the lp norm(0<p≤1).Using a numerical model,we demonstrated the higher time–frequency resolution of this method and its capability for improving the seismic interpretation for thin layers.Moreover,given the actual underground geology that can be often complex,we further propose a p-norm constrained inverse spectral attribute interpretation method based on multiresolution time–frequency feature fusion.By comprehensively analyzing the time–frequency spectrum results constrained by the diff erent p-norms,we can obtain more refined interpretation results than those obtained by the traditional strategy,which incorporates a single norm constraint.Finally,the proposed strategy was applied to the processing and interpretation of actual three-dimensional seismic data for a study area covering about 230 km^(2) in western China.The results reveal that the surface water system in this area is characterized by stepwise convergence from a higher position in the north(a buried hill)toward the south and by the development of faults.We thus demonstrated that the proposed method has huge application potential in seismic interpretation.展开更多
Tumor microenvironment(TME)is highly heterogeneous and composed of complex cellular components,including multiple kinds of immune cells.Among all immune cells in TME,tumor-infiltrating myeloid cells(TIMs)account for a...Tumor microenvironment(TME)is highly heterogeneous and composed of complex cellular components,including multiple kinds of immune cells.Among all immune cells in TME,tumor-infiltrating myeloid cells(TIMs)account for a large proportion and play roles as key regulators in a variety of functions,ranging from immune-mediated tumor killing to tumor immune evasion.Understanding the heterogeneity of TIMs will provide valuable insights for new therapeutic targeting of myeloid cells.Single-cell genomic technologies deciphering cell composition and gene expression at single-cell resolution have largely improved our understanding of the cellular heterogeneity of TIMs and highlighted several novel cell subtypes contributing to the variation of patient survival and treatment response.However,these cell subtypes were defined based on limited data without a concordant nomenclature,which makes it difficult to understand whether they exist in different studies.Thus,in this review,we comprehensively summarized the common agreements and current different opinions on the heterogeneity of TIMs gained from single-cell studies;evaluated the feasibility of current myeloid cell targets at single-cell level and proposed a uniform nomenclature for TIM subsets.展开更多
The conversion of waste tire pyrolysis oil(WTPO)into S-doped porous carbon nanorods(labeled as WPCNs)with hierarchical pore structure is realized by a simple template-directed approach.The specific surface area of as-...The conversion of waste tire pyrolysis oil(WTPO)into S-doped porous carbon nanorods(labeled as WPCNs)with hierarchical pore structure is realized by a simple template-directed approach.The specific surface area of as-obtained porous carbon nanorods can reach up to 1448 m^(2) g^(−1) without the addition of any activating agent.As the capacitive electrode,WPCNs possess the extraordinary compatibility to capacitance,different electrolyte systems as well as long-term cycle life even at a commercial-level areal mass loading(10 mg cm^(−2)).Besides,only an extremely small capacitance fluctuation is observed under the extreme circumstance(−40 to 80℃),reflecting the excellent high-and low-temperature performance.The relationship between the pore structure and capacitive behavior is analyzed by comparing WPCNs with mesopores-dominated asphalt-derived porous carbon nanorods(APCNs)and micropores-dominated activated carbon.The molecular dynamics simulation further reveals the ion diffusion and transfer ability of the as-prepared carbon materials under different pore size distribution.The total ion flow(NT)of WPCNs calculated by the simulation is obviously larger than APCNs and the N_(T) ratio between them is similar with the experimental average capacitance ratio.Furthermore,this work also provides a valuable strategy to prepare the electrode material with high capacitive energy storage ability through the high value-added utilization of WTPO.展开更多
Lithium metal has a high theoretical capacity of 3860 mAh g^-1 and a low electrochemical potential(-3.04 V vs.H2/H^+).Hence,using a lithium anode significantly improves the energy density of a secondary battery.Howeve...Lithium metal has a high theoretical capacity of 3860 mAh g^-1 and a low electrochemical potential(-3.04 V vs.H2/H^+).Hence,using a lithium anode significantly improves the energy density of a secondary battery.However,the lithium dendrites generated on the lithium anode during the platingdissolution process significantly reduce its cycling life and safety.Here,we provide a simple method for lithium anode protection,by applying a free-standing porous carbon film with a high specific surface area to reduce the local current density and obtain a homogenous ion distribution.The protected lithium anode has a long cycle life over 1000 h when cycled at 3 mA cm^-2 with a lithium capacity of 2.5 mAh cm^-2.Moreover,the deposited lithium has a smoother surface than Li anode without carbon protection.This study will promote the wide application of Li-metal-based batteries with high safety levels.展开更多
: Four typical distribution patterns of pentacyclic triterpenoid hydrocarbons (types A-D) are distinguished in the low-mature source rocks from eastern China. Type A has a relatively high content of pentacyclic triter...: Four typical distribution patterns of pentacyclic triterpenoid hydrocarbons (types A-D) are distinguished in the low-mature source rocks from eastern China. Type A has a relatively high content of pentacyclic triterpenes. It exists in immature sediments and the distribution and abundance of triterpenes vary with the maturity of the sediments. An unknown C30 triterpene (UCT2) has also been detected in very shallow sediments. This compound is very unstable and disappears rapidly with the increase of depth. Type B is characterized by a relatively high amount of 17α(H), 21β(H)-30-homohopane. This kind of distribution pattern is common in coals and terrestrial sediments of low maturity. Type C has a relatively high content of diahopane and neohopane series. The analysis shows that this distribution pattern may have an indirect relationship with the input of higher plants despite its microbial source. There are C30—unconfirmed triterpane (UCT2) and a relatively high content of C35 hopane in type D. The distribution patterns of pentacyclic triterpenoids are varied under influences of biological sources, diagentic and sedimentary environments, thermal maturity etc. Therefore, they can provide useful information about the source rocks. Based on geochemical characteristics of the source rocks, the authors postulated that the type B and type C patterns are mainly related to suboxic-anoxic environments. Type D indicates the reducing to anoxic environment, in which C30-UCT3 may be related to some specific biological source in saline environments. The precursors and thermal evolution of some triterpenoid hydrocarbons are also discussed herein.展开更多
Developing a highly active and durable non-noble metal catalyst for aqueous-phase levulinic acid(LA)hydrogenation to g-valerolactone(GVL)is an appealing yet challenging task.Herein,we report well-dispersed Co nanopart...Developing a highly active and durable non-noble metal catalyst for aqueous-phase levulinic acid(LA)hydrogenation to g-valerolactone(GVL)is an appealing yet challenging task.Herein,we report well-dispersed Co nanoparticles(NPs)embedded in nitrogen-doped mesoporous carbon nanofibers as an efficient catalyst for aqueous-phase LA hydrogenation to GVL.The Co zeolitic imidazolate framework(ZIF-67)nanocrystals were anchored on the sodium dodecyl sulfate modified wipe fiber(WF-S),yielding one-dimensional(1-D)structured composite(ZIF-67/WF-S).Subsequently,Co NPs were uniformly embedded in nitrogen-doped mesoporous carbon nanofibers(Co^(R)NC/SMCNF)through a pyrolysis-reduction strategy using ZIF-67/WF-S as the precursor.Benefiting from introducing modified wipe fiber WF-S to enhance the dispersion of Co NPs,and Co^(0) with Co-N_xdual active sites,the resulting Co^(R)NC/SMCNF catalyst shows brilliant catalytic activity(206 h^(-1) turnover frequency).Additionally,the strong metal-support interactions greatly inhibited the Co NPs from aggregation and leaching from the mesoporous carbon nanofibers,and thus increasing the reusability of the Co^(R)NC/SMCNF catalyst(reusable nine times without notable activity loss).展开更多
基金financed by the National Key Research and Development Program of China[grants number 2022YFB3803800]the National Natural Science Foundation of China[grants number 52071141,52271212,52201250,51771056]Interdisciplinary Innovation Program of North China Electric Power University[grants number XM2112355].
文摘At present,there is limited research on the application of fuel cell power generation system technology using solid hydrogen storage materials,especially in hydrogen-assisted two-wheelers.Considering the disadvantages of low hydrogen storage capacity and poor kinetics of hydrogen storage materials,our primary focus is to achieve smooth hydrogen ab-/desorption over a wide temperature range to meet the requirements of fuel cells and their integrated power generation systems.In this paper,the Ti_(0.9)Zr_(0.1)Mn_(1.45)V_(0.4)Fe_(0.15) hydrogen storage alloy was successfully prepared by arc melting.The maximum hydrogen storage capacity reaches 1.89 wt% at 318 K.The alloy has the capability to absorb 90% of hydrogen storage capacity within 50 s at 7 MPa and release 90% of hydrogen within 220 s.Comsol Multiphysics 6.0 software was used to simulate the hydrogen ab-/desorption processes of the tank.The flow rate of cooling water during hydrogen absorption varied in a gradient of(0.02 t x)m s^(-1)(x=0,0.02,0.04,0.06,0.08,0.1,0.12).Cooling water flow rate is positively correlated with the hydrogen absorption rate but negatively correlated with the cost.When the cooling rate is 0.06 m s^(-1),both simulation and experimentation have shown that the hydrogen storage tank is capable of steady hydrogen desorption for over 6 h at a flow rate of 2 L min^(-1).Based on the above conclusions,we have successfully developed a hydrogen-assisted two-wheeler with a range of 80 km and achieved regional demonstration operations in Changzhou and Shaoguan.This paper highlights the achievements of our team in the technological development of fuel cell power generation systems using solid hydrogen storage materials as hydrogen storage carriers and their application in twowheelers in recent years.
文摘Through continuous equipment technology transformation and full utilization of Ma Steel's abundant gas,the boiler no longer relies on fuel oil for stable combustion during boiler startup,sliding parameter shutdown,and RB,thus achieving safe and stable operation of the boiler under any abnormal working conditions,and achieving good economic and social benefits.
基金supported by the grant from China-Japan Friendship Hospital Talent Introduction Research Start-up Fund(to Guang ying ZHU)(No.2016-RC-4)。
文摘Background and objective Low-density computed tomography(LDCT)improved early lung cancer diagnosis but introduces an excess of false-positive pulmonary nodules data.Hence,accurate diagnosis of early-stage lung cancer remains challenging.The purpose of the study was to assess the feasibility of using circulating tumour cells(CTCs)to differentiate malignant from benign pulmonary nodules.Materials and methods 122 patients with suspected malignant pulmonary nodules detected on chest CT in preparation for surgery were prospectively recruited.Peripheral blood samples were collected before surgery,and CTCs were identified upon isolation by size of epithelial tumour cells and morphological analysis.Laser capture microdissection,MALBAC amplification,and whole-exome sequencing were performed on 8 samples.The diagnostic efficacy of CTCs counting,and the genomic variation profile of benign and malignant CTCs samples were analysed.Results Using 2.5 cells/5 m L as the cut-off value,the area under the receiver operating characteristic curve was of 0.651(95%confidence interval:0.538-0.764),with a sensitivity and specificity of 0.526 and 0.800,respectively,and positive and negative predictive values of 91.1%and 30.3%,respectively.Distinct sequence variations differences in DNA damage repair-related and driver genes were observed in benign and malignant samples.TP53 mutations were identified in CTCs of four malignant cases;in particular,g.7578115T>C,g.7578645C>T,and g.7579472G>C were exclusively detected in all four malignant samples.Conclusion CTCs play an ancillary role in the diagnosis of pulmonary nodules.TP53 mutations in CTCs might be used to identify benign and malignant pulmonary nodules.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51991361)the foundation of China University of Petroleum(Beijing)(Grant No.2462021YXZZ002).
文摘With increasing drilling depth and large dosage of weighting materials,drilling fluids with high solid content are characterized by poor stability,high viscosity,large water loss,and thick mud cake,easier leading to reservoir damage and wellbore instability.In this paper,micronized barite(MB)was modified(mMB)by grafting with hydrophilic polymer onto the surface through the free radical polymerization to displace conventional API barite partly.The suspension stability of water-based drilling fluids(WBDFs)weighted with API barite:mMB=2:1 in 600 g was significantly enhanced compared with that with API barite/WBDFs,exhibiting the static sag factor within 0.54 and the whole stability index of 2.The viscosity and yield point reached the minimum,with a reduction of more than 40%compared with API barite only at the same density.Through multi-stage filling and dense accumulation of weighting materials and clays,filtration loss was decreased,mud cake quality was improved,and simultaneously it had great reservoir protection performance,and the permeability recovery rate reached 87%.In addition,it also effectively improved the lubricity of WBDFs.The sticking coefficient of mud cake was reduced by 53.4%,and the friction coefficient was 0.2603.Therefore,mMB can serve as a versatile additive to control the density,rheology,filtration,and stability of WBDFs weighted with API barite,thus regulating comprehensive performance and achieving reservoir protection capacity.This work opened up a new path for the productive drilling of extremely deep and intricate wells by providing an efficient method for managing the performance of high-density WBDFs.
文摘Deep shale reservoirs(3500–4500 m)exhibit significantly different stress states than moderately deep shale reservoirs(2000–3500 m).As a result,the brittleness response mechanisms of deep shales are also different.It is urgent to investigate methods to evaluate the brittleness of deep shales to meet the increasingly urgent needs of deep shale gas development.In this paper,the quotient of Young’s modulus divided by Poisson’s ratio based on triaxial compression tests under in situ stress conditions is taken as SSBV(Static Standard Brittleness Value).A new and pragmatic technique is developed to determine the static brittleness index that considers elastic parameters,the mineral content,and the in situ stress conditions(BIEMS).The coefficient of determination between BIEMS and SSBV reaches 0.555 for experimental data and 0.805 for field data.This coefficient is higher than that of other brittleness indices when compared to SSBV.BIEMS can offer detailed insights into shale brittleness under various conditions,including different mineral compositions,depths,and stress states.This technique can provide a solid data-based foundation for the selection of‘sweet spots’for single-well engineering and the comparison of the brittleness of shale gas production layers in different areas.
基金partially supported by the Science Foundation of China University of Petroleum,Beijing(2462023XKBH013)the National Natural Science Foundation of China(52202405)。
文摘Cooperation among enterprises can bring overall and individual performance improvement,and a smooth coordination method is indispensable.However,due to the lack of customized coordination methods,cooperation in the downstream oil supply chain cannot be carried out smoothly.This paper intends to propose a multi-party coordination method to promote cooperation between oil shippers and pipeline operator by optimizing oil transportation,oil substitution and pipeline pricing schemes.An integrated game-theoretic modeling and analysis approach is developed to characterize the operation behaviors of all stakeholders in the downstream oil supply chain.The proposed mixed integer nonlinear programming model constrains supply and demand capacity,transportation routes,oil substitution rules and pipeline freight levels.Logarithm transformation and price discretization are introduced for model linear approximation.Simulation experiments are carried out in the oil distribution system in South China.The results show that compared to the business-as-usual scheme,the new scheme saves transportation cost by 3.48%,increases pipeline turnover by 5.7%,and reduces energy consumption and emissions by 7.66%and 6.77%.It is proved that the proposed method improves the revenue of the whole system,achieves fair revenue distribution,and also improves the energy and environmental benefits of the oil supply chain.
基金CAMS initiative for Innovative Medicine of China,Grant/Award Number:2021-I2M-1-034。
文摘Background:Apolipoprotein E4(ApoE4)allele is the strongest genetic risk factor for late-onset Alzheimer's disease,and it can aggravate depressive symptoms in non-AD patients.However,the impact of ApoE4 on AD-associated depression-l ike behaviors and its underlying pathogenic mechanisms remain unclear.Methods:This study developed a 5xFAD mouse model overexpressing human ApoE4(E4FAD).Behavioral assessments and synaptic function tests were conducted to explore the effects of ApoE4 on cognition and depression in 5xFAD mice.Changes in peripheral and central lipid metabolism,as well as the levels of serotonin(5-HT)andγ-aminobutyric acid(GABA)neurotransmitters in the prefrontal cortex,were examined.In addition,the protein levels of 24-dehydrocholesterol reductase/glycogen synthase kinase-3 beta/mammalian target of rapamycin(DHCR24/GSK3β/m TOR)and postsynaptic density protein 95/calmodulin-dependent protein kinase II/brain-derived neurotrophic factor(PSD95/CaMK-II/BDNF)were measured to investigate the molecular mechanism underlying the effects of ApoE4 on AD mice.Results:Compared with 5xFAD mice,E4FAD mice exhibited more severe depressionlike behaviors and cognitive impairments.These mice also exhibited increased amyloid-beta deposition in the hippocampus,increased astrocyte numbers,and decreased expression of depression-related neurotransmitters 5-HT and GABA in the prefrontal cortex.Furthermore,lipid metabolism disorders were observed in E4FAD,manifesting as elevated low-density lipoprotein cholesterol and reduced high-density lipoprotein cholesterol in peripheral blood,decreased cholesterol level in the prefrontal cortex,and reduced expression of key enzymes and proteins related to cholesterol synthesis and homeostasis.Abnormal expression of proteins related to the DHCR24/GSK3β/m TOR and PSD95/CaMK-II/BDNF pathways was also observed.Conclusion:This study found that ApoE4 overexpression exacerbates depressionlike behaviors in 5xFAD mice and confirmed that ApoE4 reduces cognitive function in these mice.The mechanism may involve the induction of central and peripheral lipid metabolism disorders.Therefore,modulating ApoE expression or function to restore cellular lipid homeostasis may be a promising therapeutic target for AD comorbid with depression.This study also provided a better animal model for studying AD comorbid with depression.
文摘Objective: To explore the clinical value of surgical treatment and postoperative anti-infection treatment for acute suppurative appendicitis. Methods: A total of 116 patients with acute suppurative appendicitis were enrolled in this study. The collection period was from December 2021 to December 2023. The patients were randomly grouped into a control group (surgical treatment) and an observation group (surgical treatment and postoperative anti-infection treatment), of 58 patients each. At the end of the treatment, the results of each index of the two groups were compared. Results: The length of hospitalization time, exhaust time, and incidence of complications in the observation group were shorter than those of the control group (P < 0.05). The total effective rate of the observation group was higher than that of the control group (P < 0.05). Conclusion: It is crucial to perform anti-infective treatment promptly after surgical treatment in patients with acute suppurative appendicitis. It can effectively prevent the occurrence of complications and improve the clinical efficacy. Hence, it is worthy of research and promotion.
基金supported by grants from the Mission Plan Program of Beijing Municipal Administration of Hospitals(SML20152201)Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding(ZYLX201712)+1 种基金the National Natural Science Foundation of China(81427803)Beijing Tsinghua Changgung Hospital Fund(12015C1039)
文摘Background: Augmented reality(AR) technology is used to reconstruct three-dimensional(3D) images of hepatic and biliary structures from computed tomography and magnetic resonance imaging data, and to superimpose the virtual images onto a view of the surgical field. In liver surgery, these superimposed virtual images help the surgeon to visualize intrahepatic structures and therefore, to operate precisely and to improve clinical outcomes.Data Sources: The keywords "augmented reality", "liver", "laparoscopic" and "hepatectomy" were used for searching publications in the Pub Med database. The primary source of literatures was from peer-reviewed journals up to December 2016. Additional articles were identified by manual search of references found in the key articles.Results: In general, AR technology mainly includes 3D reconstruction, display, registration as well as tracking techniques and has recently been adopted gradually for liver surgeries including laparoscopy and laparotomy with video-based AR assisted laparoscopic resection as the main technical application. By applying AR technology, blood vessels and tumor structures in the liver can be displayed during surgery,which permits precise navigation during complex surgical procedures. Liver transformation and registration errors during surgery were the main factors that limit the application of AR technology.Conclusions: With recent advances, AR technologies have the potential to improve hepatobiliary surgical procedures. However, additional clinical studies will be required to evaluate AR as a tool for reducing postoperative morbidity and mortality and for the improvement of long-term clinical outcomes. Future research is needed in the fusion of multiple imaging modalities, improving biomechanical liver modeling,and enhancing image data processing and tracking technologies to increase the accuracy of current AR methods.
基金Supported by National Natural Science Foundation of China(30870109)
文摘The epidemiology of highly pathogenic porcine reproductive and respiratory syndrome( HP-PRRS) in Changping District,Beijing City was investigated from 2010 to 2015. Through statistics of vaccine,immune procedure and antibody levels,the epidemic prevention effect of HP-PRRS in Changping District was scientifically assessed.
基金Project supported by the Creative Foundation for Young-Middle-Aged Researchers from CNPC 2006–2008
文摘The development of coalbed methane (CBM) in China poses great difficulties because of high investments, low produc- tion and high risks. So a study of the economic effect of a single well at its preliminary stage is helpful for commercial exploitation of CBM. Affected by wellbore flow pressure, initial reservoir pressure, relative permeability, Langmuir pressure and other factors, the trend of declining production of a single CBM well agrees, by and large, with a hyperbolic pattern of decline. Based on Arps’s equation, nearly 200 wells production with different peak yields and initial rates of were simulated. Given the present cost of drill- ing, gas production and engineering on the ground, the gross investment for the development of a single coalbed methane well was estimated for the Fanzhuang block in central China. Considering the current industrial policies for CBM, we established an eco- nomic assessment model and analyzed economic peaks. The results show the economic benefits with or without government subsi- dies at different peak yields of a single CBM well. The results of the evaluation can be directly applied in the Fanzhuang block. The evaluation method, formulated in our study, can be used to other areas with similar conditions.
基金supported by the National Key Research and Development Program of China (2019YFA0210300)the NSF of China (21922802)+3 种基金the Beijing Natural Science Foundation (JQ19007)Talent cultivation and open project (OIC- 201801007) of State Key Laboratory of Organic-Inorganic Composites“Double-First-Class” construction projects (XK180301, XK180402)Distinguished Scientist Program at BUCT (buctylkxj02)。
文摘Hierarchically porous architecture of ir on-nitroge n-carb on(Fe-N-C)for oxyge n reducti on reaction(ORR)is highly desired towards efficient mass transfer in the fuel cell device manner.Herein,we reported a binary ligand strategy to prepare zeolitic imidazolate frameworks(ZIFs)-derived precursors,wherein the addition of secondary ligand endows precursors with the capabilities to transform into porously interweaved encapsulation-nanotubes structured composites after calcination.The optimal catalyst,i.e.,termed as Fe_(6)-M/C-3,exhibits excellent durability with 88.8%current retention after 50,000 seconds in 0.1 M HClO_(4)solution by virtue of nanoparticles-encapsulation features,which is more positive than the benchmark commercial 20 wt%Pt/C catalyst.Moreover,a promising maximum power density of Fe_(6)-M/C-3 as cathode catalyst was also dem on strated in proton exchange membrane fuel cells(PEMFCs)measurements.Therefore,this binary ligand approach to the fabrication of hierarchically porous structures would also have significant implications for various other electrochemical reactions.
基金supported by the National Basil Research Program of China(973 Program) 2010CBS30200(2010CB530206)the grants from the National Key Science and Technolog Projects of China,No.2009ZX10004-203 and 2008ZX10004-008)
文摘Objective:To evaluate the detection of IgM and IgG antibodies to Orientia tsutsugamushi(O. tsutsugamushi) by rapid diagnostic test(RDT) and microimmunofluorescence assay(ml FA). Methods:RDT using a mixture of recombinant 56-kDa proteins of O.tsutsugamushi and mIFA assay were performed on 20 patients from Fujian and 13 patients from Yunnan Province,and 82 sera samples from healthy farmers in Anhui Province and Beijing City in 2009.Comparison of the RDT and mIFA assay was performed by using X test and the P level of 【0.05 was considered to be significance.Results:Among these 82 normal sera samples,the specificity of RDT was 100%for both IgM and IgG tests.In 33 samples from patients with scrub typhus,5 cases were positively detected earlier by RDT than by mIFA in IgM test,and 2 cases were positive in IgG test.Sensitivities of RDT were 93.9%and 90.9%for IgM and IgG,respectively.The sensitivity of combination lest of IgM and IgG was 100%.Geometric mean titer diluted sera from confirmed cases by IFA and RDT assay were 1:37 vs.1:113(P【0.001) in IgM test and 1:99 vs.1:279 (P【0.05) in IgG test.Conclusions:RDT is more sensitivite than mIFA in the early diagnosis of scrub typhus and it is particularly applicable in rural areas.
基金Projects 40572085 supported by the National Natural Science Foundation of ChinaNCET-06 by the New-Century Excellent Talent Program of the Min- istry of Education
文摘The metamorphism and hydrocarbon generation from the Upper Paleozoic coal-bearing strata in Northern China have been widely studied by Chinese geologists since the 1990s. Based on a large amount of data of Ro values,combined with geological background,we have systematically analyzed the thermal evolutionary characteristics of or-ganic matter and the stages of hydrocarbon generation from the Permo-Carboniferous coal deposits and discussed the condition of secondary hydrocarbon generation. The distribution range of secondary hydrocarbon generation in North-ern China is thus determined. It is shown that the coal ranks of the Upper Paleozoic coal deposits are higher in the southern and western belts than those in the northern and eastern belts. Really significant secondary hydrocarbon gen-eration is mainly related to the thermal evolution of organic matter during the Himalayan Period. Profitable areas for secondary hydrocarbon generation should be buried at 3000-4000 m up to the present. Maturity of the Permo-Carbon-iferous source rocks is not very high. It is suggested that the Bohai Bay depression is favourable for secondary hydro-carbon generation and has good oil and gas prospects.
基金supported by National Natural Science Foundation of China (Grant No. 41974140)the PetroChina Prospective,Basic,and Strategic Technology Research Project (No. 2021DJ0606)
文摘Spectral decomposition has been widely used in the detection and identifi cation of underground anomalous features(such as faults,river channels,and karst caves).However,the conventional spectral decomposition method is restrained by the window function,and hence,it mostly has low time–frequency focusing and resolution,thereby hampering the fi ne interpretation of seismic targets.To solve this problem,we investigated the sparse inverse spectral decomposition constrained by the lp norm(0<p≤1).Using a numerical model,we demonstrated the higher time–frequency resolution of this method and its capability for improving the seismic interpretation for thin layers.Moreover,given the actual underground geology that can be often complex,we further propose a p-norm constrained inverse spectral attribute interpretation method based on multiresolution time–frequency feature fusion.By comprehensively analyzing the time–frequency spectrum results constrained by the diff erent p-norms,we can obtain more refined interpretation results than those obtained by the traditional strategy,which incorporates a single norm constraint.Finally,the proposed strategy was applied to the processing and interpretation of actual three-dimensional seismic data for a study area covering about 230 km^(2) in western China.The results reveal that the surface water system in this area is characterized by stepwise convergence from a higher position in the north(a buried hill)toward the south and by the development of faults.We thus demonstrated that the proposed method has huge application potential in seismic interpretation.
文摘Tumor microenvironment(TME)is highly heterogeneous and composed of complex cellular components,including multiple kinds of immune cells.Among all immune cells in TME,tumor-infiltrating myeloid cells(TIMs)account for a large proportion and play roles as key regulators in a variety of functions,ranging from immune-mediated tumor killing to tumor immune evasion.Understanding the heterogeneity of TIMs will provide valuable insights for new therapeutic targeting of myeloid cells.Single-cell genomic technologies deciphering cell composition and gene expression at single-cell resolution have largely improved our understanding of the cellular heterogeneity of TIMs and highlighted several novel cell subtypes contributing to the variation of patient survival and treatment response.However,these cell subtypes were defined based on limited data without a concordant nomenclature,which makes it difficult to understand whether they exist in different studies.Thus,in this review,we comprehensively summarized the common agreements and current different opinions on the heterogeneity of TIMs gained from single-cell studies;evaluated the feasibility of current myeloid cell targets at single-cell level and proposed a uniform nomenclature for TIM subsets.
基金supported by the National Key Research and Development Program of China(No.2018YFC1902603).
文摘The conversion of waste tire pyrolysis oil(WTPO)into S-doped porous carbon nanorods(labeled as WPCNs)with hierarchical pore structure is realized by a simple template-directed approach.The specific surface area of as-obtained porous carbon nanorods can reach up to 1448 m^(2) g^(−1) without the addition of any activating agent.As the capacitive electrode,WPCNs possess the extraordinary compatibility to capacitance,different electrolyte systems as well as long-term cycle life even at a commercial-level areal mass loading(10 mg cm^(−2)).Besides,only an extremely small capacitance fluctuation is observed under the extreme circumstance(−40 to 80℃),reflecting the excellent high-and low-temperature performance.The relationship between the pore structure and capacitive behavior is analyzed by comparing WPCNs with mesopores-dominated asphalt-derived porous carbon nanorods(APCNs)and micropores-dominated activated carbon.The molecular dynamics simulation further reveals the ion diffusion and transfer ability of the as-prepared carbon materials under different pore size distribution.The total ion flow(NT)of WPCNs calculated by the simulation is obviously larger than APCNs and the N_(T) ratio between them is similar with the experimental average capacitance ratio.Furthermore,this work also provides a valuable strategy to prepare the electrode material with high capacitive energy storage ability through the high value-added utilization of WTPO.
文摘Lithium metal has a high theoretical capacity of 3860 mAh g^-1 and a low electrochemical potential(-3.04 V vs.H2/H^+).Hence,using a lithium anode significantly improves the energy density of a secondary battery.However,the lithium dendrites generated on the lithium anode during the platingdissolution process significantly reduce its cycling life and safety.Here,we provide a simple method for lithium anode protection,by applying a free-standing porous carbon film with a high specific surface area to reduce the local current density and obtain a homogenous ion distribution.The protected lithium anode has a long cycle life over 1000 h when cycled at 3 mA cm^-2 with a lithium capacity of 2.5 mAh cm^-2.Moreover,the deposited lithium has a smoother surface than Li anode without carbon protection.This study will promote the wide application of Li-metal-based batteries with high safety levels.
文摘: Four typical distribution patterns of pentacyclic triterpenoid hydrocarbons (types A-D) are distinguished in the low-mature source rocks from eastern China. Type A has a relatively high content of pentacyclic triterpenes. It exists in immature sediments and the distribution and abundance of triterpenes vary with the maturity of the sediments. An unknown C30 triterpene (UCT2) has also been detected in very shallow sediments. This compound is very unstable and disappears rapidly with the increase of depth. Type B is characterized by a relatively high amount of 17α(H), 21β(H)-30-homohopane. This kind of distribution pattern is common in coals and terrestrial sediments of low maturity. Type C has a relatively high content of diahopane and neohopane series. The analysis shows that this distribution pattern may have an indirect relationship with the input of higher plants despite its microbial source. There are C30—unconfirmed triterpane (UCT2) and a relatively high content of C35 hopane in type D. The distribution patterns of pentacyclic triterpenoids are varied under influences of biological sources, diagentic and sedimentary environments, thermal maturity etc. Therefore, they can provide useful information about the source rocks. Based on geochemical characteristics of the source rocks, the authors postulated that the type B and type C patterns are mainly related to suboxic-anoxic environments. Type D indicates the reducing to anoxic environment, in which C30-UCT3 may be related to some specific biological source in saline environments. The precursors and thermal evolution of some triterpenoid hydrocarbons are also discussed herein.
基金financially supported by the National Key Research and Development Program of China(2018YFB1105100)the National Natural Science Foundation of China(51974339 and 51674270)the funding from Science Foundation of China University of Petroleum,Beijing(24620188JC005)。
文摘Developing a highly active and durable non-noble metal catalyst for aqueous-phase levulinic acid(LA)hydrogenation to g-valerolactone(GVL)is an appealing yet challenging task.Herein,we report well-dispersed Co nanoparticles(NPs)embedded in nitrogen-doped mesoporous carbon nanofibers as an efficient catalyst for aqueous-phase LA hydrogenation to GVL.The Co zeolitic imidazolate framework(ZIF-67)nanocrystals were anchored on the sodium dodecyl sulfate modified wipe fiber(WF-S),yielding one-dimensional(1-D)structured composite(ZIF-67/WF-S).Subsequently,Co NPs were uniformly embedded in nitrogen-doped mesoporous carbon nanofibers(Co^(R)NC/SMCNF)through a pyrolysis-reduction strategy using ZIF-67/WF-S as the precursor.Benefiting from introducing modified wipe fiber WF-S to enhance the dispersion of Co NPs,and Co^(0) with Co-N_xdual active sites,the resulting Co^(R)NC/SMCNF catalyst shows brilliant catalytic activity(206 h^(-1) turnover frequency).Additionally,the strong metal-support interactions greatly inhibited the Co NPs from aggregation and leaching from the mesoporous carbon nanofibers,and thus increasing the reusability of the Co^(R)NC/SMCNF catalyst(reusable nine times without notable activity loss).