In order to enhance the hydraulic loading rate (HLR) of a subsurface wastewater infiltration system (SWIS) used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results sh...In order to enhance the hydraulic loading rate (HLR) of a subsurface wastewater infiltration system (SWIS) used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results show that the intermittent operation mode contributes to the improvement of the HLR and the pollutant removal rate. When the wetting-drying ratio (RwD) was 1.0, the pollutant removal rate increased by (13.6 ± 0.3)% for NH3-N, (20.7 ± 1.1)% for TN, (18.6± 0.4)% for TP, (12.2 ± 0.5)% for BOD, (10.1 ± 0.3)% for COD, and (36.2 ± 1.2)% for SS, compared with pollutant removal rates under the continuous operation mode. The pollutant removal rate declined with the increase of the HLR. The effluent quality met The Reuse of Urban Recycling Water - Water Quality Standard for Scenic Environment Use (GB/T 18921-2002) even when the HLR was as high as 10 cm/d. Hydraulic conductivity, oxidation reduction potential (ORP), the quantity of nitrifying bacteria, and the pollutant removal rate of NH3-N increased with the decrease of the RWD. For the pollutant removal rates of TP, BOD, and COD, there were no significant difference (p 〈 0.05) under different RwDS. The suggested RWD was 1.0. Relative contribution of the pretreatment and SWlS to the pollutant removal was examined, and more than 80% removal of NH3-N, TN, TP, COD, and BOD occurred in the SWIS.展开更多
BACKGROUND The prognosis of intrahepatic cholangiocarcinoma(ICC) with lymph node metastasis is poor.The feasibility of surgery is not certain,which is a contraindication according to the National Comprehensive Cancer ...BACKGROUND The prognosis of intrahepatic cholangiocarcinoma(ICC) with lymph node metastasis is poor.The feasibility of surgery is not certain,which is a contraindication according to the National Comprehensive Cancer Network guidelines.The role of immunotherapy as a neoadjuvant therapy for ICC is not clear.We herein describe a case of ICC with lymph node metastasis that was successfully treated with neoadjuvant therapy.CASE SUMMARY A 60-year-old man with a liver tumor was admitted to our hospital.Enhanced computed tomography and magnetic resonance imaging revealed a spaceoccupying lesion in the right lobe of the liver.Multiple subfoci were found around the tumor,and the right posterior branch of the portal vein was invaded.Liver biopsy indicated poorly differentiated cholangiocytes.According to the American Joint Committee on Cancer disease stage classification,ICC with hilar lymph node metastasis(stage ⅢB) and para-aortic lymph node metastasis was suspected.A report showed that two patients with stage ⅢB ICC achieved a complete response(CR) 13 mo and 16 mo after chemotherapy with a PD-1 monoclonal antibody.After multidisciplinary consultation,the patient was given neoadjuvant therapy,surgical resection and lymph node dissection,and postoperative adjuvant therapy.After three rounds of PD-1 immunotherapy(camrelizumab) and two rounds of gemcitabine combined with cisplatin regimen chemotherapy,the tumor size was reduced.Therefore,a partial response was achieved.Exploratory laparotomy found that the lymph nodes of Group 16 were negative,and the tumor could be surgically removed.Therefore,the patient underwent right hemihepatectomy plus lymph node dissection.The patient received six rounds of chemotherapy and five rounds of PD-1 treatment postoperatively.After 8 mo of follow-up,no recurrence was found,and a CR was achieved.CONCLUSION Neoadjuvant therapy combined with surgical resection is useful for advanced-stage ICC.This is the first report of successful treatment of stage ⅢB ICC using neoadjuvant therapy with a PD-1 inhibitor.展开更多
We propose a boundary scheme for addressing multi-mechanism flow in a porous medium in slip and early transition flow regimes, which is frequently encountered in shale gas reservoirs. Micro-gaseous flow in organic-ric...We propose a boundary scheme for addressing multi-mechanism flow in a porous medium in slip and early transition flow regimes, which is frequently encountered in shale gas reservoirs. Micro-gaseous flow in organic-rich shale involves a complex flow mechanism. A self-developed boundary scheme that combines the non-equilibrium extrapolation scheme and the combined diffusive reflection and bounce-back scheme(half-way DBB) to embed the Langmuir slip boundary into the single-relaxation-time lattice Boltzmann method(SRT-LBM) enables us to describe this process, namely, the coupling effect of micro-gaseous flow and surface diffusion in organic-rich nanoscale pores. The present LBM model comes with the careful consideration of the local Knudsen number, local pressure gradient, viscosity correction model, and regularization procedure to account for the rarefied gas flows in irregular pores. Its validity and accuracy are verified by several benchmarking cases, and the calculated results by this boundary scheme accord well with our analytical solutions.This boundary scheme shows a higher accuracy than the existing studies. Additionally, a subiteration strategy is presented to tackle the coupled micro-gaseous flow and surface diffusion, which necessitates the iteration process matching of these two mechanisms. The multi-mechanism flow in the self-developed irregular pores is also numerically investigated and analyzed over a wide range of parameters. The results indicate that the present model can effectively capture the coupling effect of micro-gaseous flow and surface diffusion in a tree-like porous medium.展开更多
Improving the thermal stability of diamond and other superhard materials has great significance in various applications. Here, we report the synthesis and characterization of bulk diamond–cBN–B4C–Si composites sint...Improving the thermal stability of diamond and other superhard materials has great significance in various applications. Here, we report the synthesis and characterization of bulk diamond–cBN–B4C–Si composites sintered at high pressure and high temperature(HPHT, 5.2 GPa, 1620–1680 K for 3–5 min). The results show that the diamond, cBN, B4C,BxSiC, SiO2 and amorphous carbon or a little surplus Si are present in the sintered samples. The onset oxidation temperature of 1673 K in the as-synthesized sample is much higher than that of diamond, cBN, and B4C. The high thermal stability is ascribed to the covalent bonds of B–C, C–N, and the solid-solution of BxSiC formed during the sintering process. The results obtained in this work may be useful in preparing superhard materials with high thermal stability.展开更多
BACKGROUND Non-liquefied multiple liver abscesses(NMLA)can induce sepsis,septic shock,sepsis-associated kidney injury(SA-AKI),and multiple organ failure.The inability to perform ultrasound-guided puncture and drainage...BACKGROUND Non-liquefied multiple liver abscesses(NMLA)can induce sepsis,septic shock,sepsis-associated kidney injury(SA-AKI),and multiple organ failure.The inability to perform ultrasound-guided puncture and drainage to eradicate the primary disease may allow for the persistence of bacterial endotoxins and endogenous cytokines,exacerbating organ damage,and potentially causing immunosuppression and T-cell exhaustion.Therefore,the search for additional effective treatments that complement antibiotic therapy is of great importance.CASE SUMMARY A 45-year-old critically ill female patient presented to our hospital’s intensive care unit with intermittent vomiting,diarrhea,and decreased urine output.The patient exhibited a temperature of 37.8℃.Based on the results of liver ultrasonography,laboratory tests,fever,and oliguria,the patient was diagnosed with NMLA,sepsis,SA-AKI,and immunosuppression.We administered antibiotic therapy,entire care,continuous renal replacement therapy(CRRT)with an M100 hemofilter,and hemoperfusion(HP)with an HA380 hemofilter.The aforementioned treatment resulted in a substantial reduction in disease severity scores and a decrease in the extent of infection and inflammatory factors.In addition,the treatment stimulated the expansion of the cluster of differentiation 8^(+)(CD8^(+))Tcells and led to the complete recovery of renal function.The patient was discharged from the hospital.During the follow-up period of 28 d,she recovered successfully.CONCLUSION Based on the entire therapeutic regimen,the early combination of CRRT and HP therapy may control sepsis caused by NMLA and help control infections,reduce inflammatory responses,and improve CD8^(+)T-cell immune function.展开更多
The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS s...The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS spectra of these adsorption configurations have been calculated by using the density functional theory(DFT)method and fullcore hole(FCH)approximation to investigate the relationship between the adsorption configurations and the spectra.The result shows that the XPS and NEXAFS spectra are structurally dependent on the configurations of pyrrole absorbed on the Si(100)surface.Compared with the XPS,the NEXAFS spectra are relatively sensitive to the adsorption configurations and can accurately identify them.The NEXAFS decomposition spectra produced by non-equivalent carbon atoms have also been calculated and show that the spectral features vary with the diverse types of carbon atoms and their structural environments.展开更多
This article reports the morphology, size, and distribution evolution of MnS inclusions in non-quenched and tempered steel during heat treatment. The variation of single large-sized MnS inclusions at high temperature ...This article reports the morphology, size, and distribution evolution of MnS inclusions in non-quenched and tempered steel during heat treatment. The variation of single large-sized MnS inclusions at high temperature was observed in situ using a confocal scanning laser microscope (CSLM). The slender MnS inclusions first changed to pearl-like slrings. These small-sized pearls subsequently coalesced and became closer together as the temperature increased. Large-sized MnS inclusions in non-quenched and tempered steel samples with different thermal histories were investigated with respect to the evolution of their morphology, size, and distribution. After 30 min of ovulation at 1573 K, the percentage of MnS inclusions larger than 3 μm decreased from 50.5% to 3.0%. After a 3 h making period, Ostwald ripening occurred. Most MnS inclusions moved from the grain bounda- ries to the interior. The present study demonstrates that heat treatment is an effective method of changing the morphology, size, and distribution of MnS inclusions, especially large-sized ones.展开更多
Combined with NMR,core experiment,slim-tube tests,nano-CT and oil composition analysis,the mechanism of CO(2) enhanced oil recovery had been studied.CO_(2) flooding under supercritical state could achieve higher oil r...Combined with NMR,core experiment,slim-tube tests,nano-CT and oil composition analysis,the mechanism of CO(2) enhanced oil recovery had been studied.CO_(2) flooding under supercritical state could achieve higher oil recovery.In the process of crude oil displaced by supercritical CO2,the average oil recovery was 46.98% at low displacement pressures and 73.35% at high displacement pressures.The permeability of cores after CO2 flooding was only 28%-64% of those before flooding.As to the expelled oil,the contents of asphaltenes and non-hydrocarbons decreased,and saturated hydrocarbons of above C25 were absent in some samples,indicating that they had been retained in cores as demonstrated by CT and NMR experiments.In slim-tube tests,the heavy components of oil were expelled when the pressure increased to 30 MPa.There was a reasonable bottom hole pressure(BHP) below which the heavy components driven out from the far-well zone would deposit in the near-well zone,and when the pressure was too high,the nonhydrocarbon detention may cause block.The smaller throat and worse physical properties the porous media had,the higher displacement pressure would be required to achieve a good oil displacement efficiency.The increase in displacement pressure or time of interaction between oil and CO2 could effectively enhance oil recovery.展开更多
With complex fractured-vuggy heterogeneous structures, water has to be injected to facilitate oil pro- duction. However, the effect of different water injection modes on oil recovery varies. The limitation of existing...With complex fractured-vuggy heterogeneous structures, water has to be injected to facilitate oil pro- duction. However, the effect of different water injection modes on oil recovery varies. The limitation of existing numerical simulation methods in representing fractured- vuggy carbonate reservoirs makes numerical simulation difficult to characterize the fluid flow in these reservoirs. In this paper, based on a geological example unit in the Tahe Oilfield, a three-dimensional physical model was designed and constructed to simulate fluid flow in a fractured-vuggy reservoir according to similarity criteria. The model was validated by simulating a bottom water drive reservoir, and then subsequent water injection modes were optimized. These were continuous (constant rate), intermittent, and pulsed injection of water. Experimental results reveal that due to the unbalanced formation pressure caused by pulsed water injection, the swept volume was expanded and consequently the highest oil recovery increment was achieved. Similar to continuous water injection, intermit- tent injection was influenced by factors including the connectivity of the fractured-vuggy reservoir, well depth, and the injection-production relationship, which led to a relative low oil recovery. This study may provide a constructive guide to field production and for the devel- opment of the commercial numerical models specialized for fractured-vuggy carbonate reservoirs.展开更多
BACKGROUND Sarcomatoid hepatocellular carcinoma(SHC)is a rare subtype of hepatocellular carcinoma(HCC),with a high recurrence rate after surgery.In addition to limited effective treatment for the advanced stage of SHC...BACKGROUND Sarcomatoid hepatocellular carcinoma(SHC)is a rare subtype of hepatocellular carcinoma(HCC),with a high recurrence rate after surgery.In addition to limited effective treatment for the advanced stage of SHC,the prognosis of patients with this malignancy is worse than that of patients with conventional HCC.CASE SUMMARY We present the case of a 54-year-old man with SHC who underwent radical segmental hepatectomy,which relapsed 4 mo after surgery due to lymphatic metastasis in the porta hepatis.Although a second surgery was performed,new metastasis developed in the mediastinal lymph nodes.Therefore,sorafenib and lenvatinib were sequentially administered as first-and second-line systemic therapies,respectively.However,progressive disease was confirmed based on a recurrent hepatic lesion and new metastatic lesion in the abdominal cavity.Percutaneous transhepatic cholangial drainage was performed to alleviate the biliary obstruction.Because the tumor was strongly positive for programmed death-ligand 1,the patient was started on nivolumab.Imaging studies revealed that after two cycles of immunotherapy,the metastatic lesions decreased to undetectable levels.CONCLUSION The patient experienced continuous complete remission for 8 mo.Immune checkpoint inhibitors are useful for the treatment of advanced SHC.展开更多
AIM: To explore the clinical feature and genetic etiology of a Chinese Knobloch syndrome family. METHODS: Ocular examinations and magnetic resonance imagings (MRIs) were performed on the family. Whole exome sequen...AIM: To explore the clinical feature and genetic etiology of a Chinese Knobloch syndrome family. METHODS: Ocular examinations and magnetic resonance imagings (MRIs) were performed on the family. Whole exome sequencing was conducted on the two patients. Sanger sequencing was utilized to validate the presence of variation in the family as well as in 100 normal controls. Real-time uantitative polymerase chain reaction (PCR) was used to detect the expression level of COL18A1 in peripheral blood lymphocytes of the patients and normal carriers. RESULTS: The affected subjects presented with vision loss, exotropia, cataracts, retinal detachment, and other complications. A homozygous c.4759_4760delCT (p.Leu1587ValfsX72) mutation (rs398122391) in COL18A1 was identified in the two patients, cosegregating with the phenotypes, and did not be detected in 100 normal controls. This mutation caused significant decreased expression of COL18A1 mRNA in the patients. CONCLUSION: The findings strongly indicate that this mutation is the disease-causing mutation. Moreover, this is the first Knobloch syndrome pedigree reported in the Chinese population.展开更多
The concentration of total nitrogen(TN) is reported to vary between 20 and 35 mg/L in domestic wastewater. In raw wastewater, ammonia nitrogen eNHt4-NT is the main nitrogen form, accounting for 70%e82% of the TN conce...The concentration of total nitrogen(TN) is reported to vary between 20 and 35 mg/L in domestic wastewater. In raw wastewater, ammonia nitrogen eNHt4-NT is the main nitrogen form, accounting for 70%e82% of the TN concentration. Organic nitrogen, nitrite nitrogen eNOà2-NT,and nitrate nitrogen eNOà3-NT are present as well. For years, due to the lack of regulatory limits on nitrogen concentration in surface waters,nitrogen from secondary effluent has posed a significant threat to the health of aquatic ecosystems. Researchers have made substantial efforts to reduce the nitrogen concentration in secondary effluent. As a kind of advanced wastewater treatment technology, the subsurface infiltration(SI)system has been widely used, owing to its advantages, which include low operation cost, easy maintenance, and low energy consumption. This review discusses the fate of various forms of nitrogen in SI treatment, including organic nitrogen, NHt4-N, NOà2-N, and NOà3-N. Major biological processes involved in nitrogen removal and the main factors influencing its transformation are suggested. Finally, it is shown that ammonification followed by nitrification-denitrification plays a major role in nitrogen removal. Further research needs to focus on the emission characteristics of gaseous nitrogen(generated from the nitrification, denitrification, and completely autotrophic nitrogen-removal over nitrite(CANON) processes) with respect to their greenhouse effects.展开更多
AIM:To introduce a novel approach in removal of anterior chamber angle foreign body(ACFB) using a prism contact lens and 23-gauge foreign body forceps.METHODS:Data of 42 eyes of 42 patients who had undergone remov...AIM:To introduce a novel approach in removal of anterior chamber angle foreign body(ACFB) using a prism contact lens and 23-gauge foreign body forceps.METHODS:Data of 42 eyes of 42 patients who had undergone removal of ACFB using a prism contact lens and 23-gauge foreign body forceps from January 2008 to October 2013 were collected and analyzed. Twenty eyes in group A received the conventional approach by using toothed forceps through corneal limbus incision, and 22 eyes in group B underwent the novel method through the opposite corneal limbus incision. RESULTS:The success rate of ACFB once removal was 75%(15/20) in group A, and 100%(22/22) in group B. The average operation time of group A was significantly longer compared with group B(34.9±9.88 min vs 22.13±8.85min; P〈0.05). The average size of corneal limbus incision in group A was significantly larger than that of group B(4.85±1.89 mm vs 3.95±1.17 mm; P〈0.05). The corneal limbus incision suturing were conducted in all eyes in group A, and only 5 eyes in group B. CONCLUSION:Removal of ACFB using a prism contact lens and 23-gauge foreign body forceps is a safer, more effective, and convenient technique compared with the conventional approach.展开更多
The growing demand for semiconductor devices simulation poses a big challenge for large-scale electronic structure calculations.Among various methods,the linearly scaling three-dimensional fragment(LS3DF)method exhibi...The growing demand for semiconductor devices simulation poses a big challenge for large-scale electronic structure calculations.Among various methods,the linearly scaling three-dimensional fragment(LS3DF)method exhibits excellent scalability in large-scale simulations.Based on algorithmic and system-level optimizations,we propose a highly scalable and highly efficient implementation of LS3DF on a domestic heterogeneous supercomputer equipped with acceler-ators.In terms of algorithmic optimizations,the original all-band conjugate gradient algorithm is refined to achieve faster convergence,and mixed precision computing is adopted to increase overall efficiency.In terms of system-level optimiza-tions,the original two-layer parallel structure is replaced by a coarse-grained parallel method.Optimization strategies such as multi-stream,kernel fusion,and redundant computation removal are proposed to increase further utilization of the com-putational power provided by the heterogeneous machines.As a result,our optimized LS3DF can scale to a 10-million sili-con atoms system,attaining a peak performance of 34.8 PFLOPS(21.2% of the peak).All the improvements can be adapt-ed to the next-generation supercomputers for larger simulations.展开更多
Purpose: Un displaced subtle ligamentous Lisfranc injuries are easy to miss or underestimate, and many cases are treated without surgical fixation. It has not yet widely known whether conservative treatment for undisp...Purpose: Un displaced subtle ligamentous Lisfranc injuries are easy to miss or underestimate, and many cases are treated without surgical fixation. It has not yet widely known whether conservative treatment for undisplaced subtle ligamentous Lisfranc injuries may lead to a poor outcome. The purpose of this study is to compare the outcomes of conservative versus surgical management (percutaneous position screw) of undisplaced subtle ligamentous Lisfranc injury. Methods: We analysed 61 cases in this retrospective study, including 38 males and 23 females. Forty-one patients were managed conservatively, while 20 patients received surgical treatment involving minimal invasive percutaneous pos让ion screw. American orthopaedic foot &ankle society (AOFAS), foot function index (FFI, including FFI disability, FFl pain score and activity limitation scale) scores, Maryland foot score and short form-36 (SF-36) were recorded and compared after a follow-up of 10-16 months (average 12.3). Results: Patients in the surgical management group had higher scores in all evaluation methods (p < 0.05). The complications in the conservative management group had higher incidenee, mainly including secondary diastasis (34.1% vs. 5.0%), joint stiffness after 3 months (82.9% vs. 0%), and secondary arthrodesis (12.2% vs. 0%). The highest rate of complication in surgical management group was temporary forefoot pain (55.0%). Conclusion: The results of this study suggest that the outcomes of the surgical management with percutaneous position screw fixation are better than the conservative management to treat undisplaced subtle ligamentous Lisfranc injuries. This study can serve as a resource for orthopaedic surgeons in recog nizing and man aging such injuries.展开更多
This review summarizes the research outcomes and findings documented in 45 journal papers using a shared tunnel boring machine(TBM)dataset for performance prediction and boring efficiency optimization using machine le...This review summarizes the research outcomes and findings documented in 45 journal papers using a shared tunnel boring machine(TBM)dataset for performance prediction and boring efficiency optimization using machine learning methods.The big dataset was col-lected during the Yinsong water diversion project construction in China,covering the tunnel excavation of a 20 km-section with 199 items of monitoring metrics taken with an interval of one second.The research papers were the result of a call for contributions during a TBM machine learning contest in 2019 and covered a variety of topics related to the intelligent construction of TBM.This review com-prises two parts.Part I is concerned with the data processing,feature extraction,and machine learning methods applied by the contrib-utors.The review finds that the data-driven and knowledge-driven approaches in extracting important features applied by various authors are diversified,requiring further studies to achieve commonly accepted criteria.The techniques for cleaning and amending the raw data adopted by the contributors were summarized,indicating some highlights such as the importance of sufficiently high fre-quency of data acquisition(higher than 1 second),classification and standardization for the data preprocessing process,and the appro-priate selections of features in a boring cycle.The review finds that both supervised and unsupervised machine learning methods have been utilized by various researchers.The ensemble and deep learning methods have found wide applications.Part I highlights the impor-tant features of the individual methods applied by the contributors,including the structures of the algorithm,selection of hyperparam-eters,and model validation approaches.展开更多
This review discusses the application scenarios of the machine learning-supported performance prediction and the optimization effi-ciency of tunnel boring machines(TBMs).The rock mass quality ratings,which are based o...This review discusses the application scenarios of the machine learning-supported performance prediction and the optimization effi-ciency of tunnel boring machines(TBMs).The rock mass quality ratings,which are based on the Chinese code for geological survey,were used to provide"labels"suitable for supervised learning.As a result,the generation of machine prediction for rock mass grades reason-ably agreed with the ground truth documented in geological maps.In contrast,the main operational parameters,i.e.,thrust and torque,can be reasonably predicted based on historical data.Consequently,18 collapse sections of the Yinsong project have been successfully predicted by several researchers.Preliminary studies on the selection of the optimal penetration rate and cost were conducted.This review also presents a summary of the main achievements in response to the initiatives of the Lotus Pool Contest in China.For the first time,large and well-documented TBM performance data has been shared for joint scientific research.Moreover,the review discusses the technical problems that require further study and the perspectives in the future development of intelligent TBM construction based on big data and machine learning.展开更多
The performance of a recycling process for CO_(2) capture and utilization of exhaust gas in the steelmaking plant was reported.A facility capable of capturing CO_(2) at 3200 m^(3)/h was established in the steelmaking ...The performance of a recycling process for CO_(2) capture and utilization of exhaust gas in the steelmaking plant was reported.A facility capable of capturing CO_(2) at 3200 m^(3)/h was established in the steelmaking plant,resulting in the CO_(2) production of 50,000 t/a.The CO_(2) concentration of the exhaust gas from the lime kiln increased from 25.0 to 99.8 vol.%using the comprehensive method of the pressure swing adsorption and cryogenic separation.The captured and purified CO_(2) was successfully applied in the converter process by the top blowing and bottom blowing.The utilization of CO_(2) was 3.5 m^(3)/t through these two modes.After optimizing parameters of CO_(2)-O_(2) mixed top blowing,the value of[C]×[O]and the content of TFe in slag were reduced by 1.33×10-4 and 1.27%,respectively,and the dephosphorization rate of the molten steel increased by 2.31%.For the CO_(2) bottom blowing,the[N]content in the molten steel was significantly reduced by 5.7×10^(-6).展开更多
Dense nano-grained Ni_(0.7)Mn_(2.3O4) negative temperature coefficient(NTC) thermistors were fabricated by a novel two-step sintering approach that combines rapid sintering and principle of conventional two-step sinte...Dense nano-grained Ni_(0.7)Mn_(2.3O4) negative temperature coefficient(NTC) thermistors were fabricated by a novel two-step sintering approach that combines rapid sintering and principle of conventional two-step sintering technique.Samples were sintered at 1042℃ for 30 s in the first rapid step and then at 850-950℃ for 20 h in the second soaking step.Crystal phase,microstructure and electrical properties of sintered samples were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),resistance temperature relationship and aging performance.Sintered samples show a single-phase cubic spinel structure and indicate a high relative density ranging from 84% to 91% of the theoretical density.Moreover,average grain sizes of sintered samples under SEM are distributed between 254 and 570 nm.Meanwhile,the resistivity and the aging coefficient significantly decrease when soaking sintering temperature rises.In addition,the obtained material constant(B) ranges from 3931 to 3981 K.Ni_(0.7)Mn_(2.3)O_(4)-3(soaking at 900℃) and Ni_(0.7)Mn_(2.3O4)-4(soaking at 950℃) present little aging behavior,implying great electrical stability.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51108275)the Program for Liaoning Excellent Talents in Universities(LNET)(Grant No.LJQ2012101)+2 种基金the Program for New Century Excellent Talents in Universities(Grant No.NCET-11-1012)the Science and Technology Program of Liaoning Province(Grants No.2011229002 and2013229012)the Basic Science Research Fund in Northeastern University(Grants No.N130501001 and N140105003)
文摘In order to enhance the hydraulic loading rate (HLR) of a subsurface wastewater infiltration system (SWIS) used in treating domestic sewage, the intermittent operation mode was employed in the SWIS. The results show that the intermittent operation mode contributes to the improvement of the HLR and the pollutant removal rate. When the wetting-drying ratio (RwD) was 1.0, the pollutant removal rate increased by (13.6 ± 0.3)% for NH3-N, (20.7 ± 1.1)% for TN, (18.6± 0.4)% for TP, (12.2 ± 0.5)% for BOD, (10.1 ± 0.3)% for COD, and (36.2 ± 1.2)% for SS, compared with pollutant removal rates under the continuous operation mode. The pollutant removal rate declined with the increase of the HLR. The effluent quality met The Reuse of Urban Recycling Water - Water Quality Standard for Scenic Environment Use (GB/T 18921-2002) even when the HLR was as high as 10 cm/d. Hydraulic conductivity, oxidation reduction potential (ORP), the quantity of nitrifying bacteria, and the pollutant removal rate of NH3-N increased with the decrease of the RWD. For the pollutant removal rates of TP, BOD, and COD, there were no significant difference (p 〈 0.05) under different RwDS. The suggested RWD was 1.0. Relative contribution of the pretreatment and SWlS to the pollutant removal was examined, and more than 80% removal of NH3-N, TN, TP, COD, and BOD occurred in the SWIS.
基金Supported by The National 13th Five-Year Science and Technology Plan Major Projects of China,No. 2017ZX10203205-006-001 and No. 2017ZX10203205-001-003。
文摘BACKGROUND The prognosis of intrahepatic cholangiocarcinoma(ICC) with lymph node metastasis is poor.The feasibility of surgery is not certain,which is a contraindication according to the National Comprehensive Cancer Network guidelines.The role of immunotherapy as a neoadjuvant therapy for ICC is not clear.We herein describe a case of ICC with lymph node metastasis that was successfully treated with neoadjuvant therapy.CASE SUMMARY A 60-year-old man with a liver tumor was admitted to our hospital.Enhanced computed tomography and magnetic resonance imaging revealed a spaceoccupying lesion in the right lobe of the liver.Multiple subfoci were found around the tumor,and the right posterior branch of the portal vein was invaded.Liver biopsy indicated poorly differentiated cholangiocytes.According to the American Joint Committee on Cancer disease stage classification,ICC with hilar lymph node metastasis(stage ⅢB) and para-aortic lymph node metastasis was suspected.A report showed that two patients with stage ⅢB ICC achieved a complete response(CR) 13 mo and 16 mo after chemotherapy with a PD-1 monoclonal antibody.After multidisciplinary consultation,the patient was given neoadjuvant therapy,surgical resection and lymph node dissection,and postoperative adjuvant therapy.After three rounds of PD-1 immunotherapy(camrelizumab) and two rounds of gemcitabine combined with cisplatin regimen chemotherapy,the tumor size was reduced.Therefore,a partial response was achieved.Exploratory laparotomy found that the lymph nodes of Group 16 were negative,and the tumor could be surgically removed.Therefore,the patient underwent right hemihepatectomy plus lymph node dissection.The patient received six rounds of chemotherapy and five rounds of PD-1 treatment postoperatively.After 8 mo of follow-up,no recurrence was found,and a CR was achieved.CONCLUSION Neoadjuvant therapy combined with surgical resection is useful for advanced-stage ICC.This is the first report of successful treatment of stage ⅢB ICC using neoadjuvant therapy with a PD-1 inhibitor.
基金supported by the Strategic Program of Chinese Academy of Sciences(Grant No.XDB10030400)the Hundred Talent Program of Chinese Academy of Sciences(Grant No.Y323081C01)the National Natural Science Foundation of China(Grant No.51439008)
文摘We propose a boundary scheme for addressing multi-mechanism flow in a porous medium in slip and early transition flow regimes, which is frequently encountered in shale gas reservoirs. Micro-gaseous flow in organic-rich shale involves a complex flow mechanism. A self-developed boundary scheme that combines the non-equilibrium extrapolation scheme and the combined diffusive reflection and bounce-back scheme(half-way DBB) to embed the Langmuir slip boundary into the single-relaxation-time lattice Boltzmann method(SRT-LBM) enables us to describe this process, namely, the coupling effect of micro-gaseous flow and surface diffusion in organic-rich nanoscale pores. The present LBM model comes with the careful consideration of the local Knudsen number, local pressure gradient, viscosity correction model, and regularization procedure to account for the rarefied gas flows in irregular pores. Its validity and accuracy are verified by several benchmarking cases, and the calculated results by this boundary scheme accord well with our analytical solutions.This boundary scheme shows a higher accuracy than the existing studies. Additionally, a subiteration strategy is presented to tackle the coupled micro-gaseous flow and surface diffusion, which necessitates the iteration process matching of these two mechanisms. The multi-mechanism flow in the self-developed irregular pores is also numerically investigated and analyzed over a wide range of parameters. The results indicate that the present model can effectively capture the coupling effect of micro-gaseous flow and surface diffusion in a tree-like porous medium.
基金supported by the National Natural Science Foundation of China(Grant No.51301075)the Project of Development and Reform Commission of Jilin Province,China(Grant No.2014Y136)
文摘Improving the thermal stability of diamond and other superhard materials has great significance in various applications. Here, we report the synthesis and characterization of bulk diamond–cBN–B4C–Si composites sintered at high pressure and high temperature(HPHT, 5.2 GPa, 1620–1680 K for 3–5 min). The results show that the diamond, cBN, B4C,BxSiC, SiO2 and amorphous carbon or a little surplus Si are present in the sintered samples. The onset oxidation temperature of 1673 K in the as-synthesized sample is much higher than that of diamond, cBN, and B4C. The high thermal stability is ascribed to the covalent bonds of B–C, C–N, and the solid-solution of BxSiC formed during the sintering process. The results obtained in this work may be useful in preparing superhard materials with high thermal stability.
文摘BACKGROUND Non-liquefied multiple liver abscesses(NMLA)can induce sepsis,septic shock,sepsis-associated kidney injury(SA-AKI),and multiple organ failure.The inability to perform ultrasound-guided puncture and drainage to eradicate the primary disease may allow for the persistence of bacterial endotoxins and endogenous cytokines,exacerbating organ damage,and potentially causing immunosuppression and T-cell exhaustion.Therefore,the search for additional effective treatments that complement antibiotic therapy is of great importance.CASE SUMMARY A 45-year-old critically ill female patient presented to our hospital’s intensive care unit with intermittent vomiting,diarrhea,and decreased urine output.The patient exhibited a temperature of 37.8℃.Based on the results of liver ultrasonography,laboratory tests,fever,and oliguria,the patient was diagnosed with NMLA,sepsis,SA-AKI,and immunosuppression.We administered antibiotic therapy,entire care,continuous renal replacement therapy(CRRT)with an M100 hemofilter,and hemoperfusion(HP)with an HA380 hemofilter.The aforementioned treatment resulted in a substantial reduction in disease severity scores and a decrease in the extent of infection and inflammatory factors.In addition,the treatment stimulated the expansion of the cluster of differentiation 8^(+)(CD8^(+))Tcells and led to the complete recovery of renal function.The patient was discharged from the hospital.During the follow-up period of 28 d,she recovered successfully.CONCLUSION Based on the entire therapeutic regimen,the early combination of CRRT and HP therapy may control sepsis caused by NMLA and help control infections,reduce inflammatory responses,and improve CD8^(+)T-cell immune function.
基金Project supported by the Shandong Provincial Natural Science Foundation,China(Grant Nos.ZR2022MA025 and ZR2020MA077).
文摘The possible configurations of pyrrole absorbed on a Si(100)surface have been investigated by x-ray photoelectron spectroscopy(XPS)and near-edge x-ray absorption fine structure(NEXAFS)spectra.The C-1s XPS and NEXAFS spectra of these adsorption configurations have been calculated by using the density functional theory(DFT)method and fullcore hole(FCH)approximation to investigate the relationship between the adsorption configurations and the spectra.The result shows that the XPS and NEXAFS spectra are structurally dependent on the configurations of pyrrole absorbed on the Si(100)surface.Compared with the XPS,the NEXAFS spectra are relatively sensitive to the adsorption configurations and can accurately identify them.The NEXAFS decomposition spectra produced by non-equivalent carbon atoms have also been calculated and show that the spectral features vary with the diverse types of carbon atoms and their structural environments.
文摘This article reports the morphology, size, and distribution evolution of MnS inclusions in non-quenched and tempered steel during heat treatment. The variation of single large-sized MnS inclusions at high temperature was observed in situ using a confocal scanning laser microscope (CSLM). The slender MnS inclusions first changed to pearl-like slrings. These small-sized pearls subsequently coalesced and became closer together as the temperature increased. Large-sized MnS inclusions in non-quenched and tempered steel samples with different thermal histories were investigated with respect to the evolution of their morphology, size, and distribution. After 30 min of ovulation at 1573 K, the percentage of MnS inclusions larger than 3 μm decreased from 50.5% to 3.0%. After a 3 h making period, Ostwald ripening occurred. Most MnS inclusions moved from the grain bounda- ries to the interior. The present study demonstrates that heat treatment is an effective method of changing the morphology, size, and distribution of MnS inclusions, especially large-sized ones.
基金financial support from the National Science and Technology Major Project (2017ZX05013-001, 2017ZX05069003, 2017ZX05049005-004)Ministry of Science and Technology of PetroChina (2021ZZ01-03, kt2021-09-05, 2021DJ1806, 2017E-1514, 2018E-11-05)。
文摘Combined with NMR,core experiment,slim-tube tests,nano-CT and oil composition analysis,the mechanism of CO(2) enhanced oil recovery had been studied.CO_(2) flooding under supercritical state could achieve higher oil recovery.In the process of crude oil displaced by supercritical CO2,the average oil recovery was 46.98% at low displacement pressures and 73.35% at high displacement pressures.The permeability of cores after CO2 flooding was only 28%-64% of those before flooding.As to the expelled oil,the contents of asphaltenes and non-hydrocarbons decreased,and saturated hydrocarbons of above C25 were absent in some samples,indicating that they had been retained in cores as demonstrated by CT and NMR experiments.In slim-tube tests,the heavy components of oil were expelled when the pressure increased to 30 MPa.There was a reasonable bottom hole pressure(BHP) below which the heavy components driven out from the far-well zone would deposit in the near-well zone,and when the pressure was too high,the nonhydrocarbon detention may cause block.The smaller throat and worse physical properties the porous media had,the higher displacement pressure would be required to achieve a good oil displacement efficiency.The increase in displacement pressure or time of interaction between oil and CO2 could effectively enhance oil recovery.
基金supported by China National Science and Technology Major Project(2011ZX05009-004,2011ZX05014-003)National Key Basic Research and Development Program(973 Program),China(2011CB201006)Science Foundation of China University of Petroleum,Beijing(2462014YJRC053)
文摘With complex fractured-vuggy heterogeneous structures, water has to be injected to facilitate oil pro- duction. However, the effect of different water injection modes on oil recovery varies. The limitation of existing numerical simulation methods in representing fractured- vuggy carbonate reservoirs makes numerical simulation difficult to characterize the fluid flow in these reservoirs. In this paper, based on a geological example unit in the Tahe Oilfield, a three-dimensional physical model was designed and constructed to simulate fluid flow in a fractured-vuggy reservoir according to similarity criteria. The model was validated by simulating a bottom water drive reservoir, and then subsequent water injection modes were optimized. These were continuous (constant rate), intermittent, and pulsed injection of water. Experimental results reveal that due to the unbalanced formation pressure caused by pulsed water injection, the swept volume was expanded and consequently the highest oil recovery increment was achieved. Similar to continuous water injection, intermit- tent injection was influenced by factors including the connectivity of the fractured-vuggy reservoir, well depth, and the injection-production relationship, which led to a relative low oil recovery. This study may provide a constructive guide to field production and for the devel- opment of the commercial numerical models specialized for fractured-vuggy carbonate reservoirs.
基金The National 13th Five-Year Science and Technology Plan Major Projects of China,No.2017ZX10203205-006-001.
文摘BACKGROUND Sarcomatoid hepatocellular carcinoma(SHC)is a rare subtype of hepatocellular carcinoma(HCC),with a high recurrence rate after surgery.In addition to limited effective treatment for the advanced stage of SHC,the prognosis of patients with this malignancy is worse than that of patients with conventional HCC.CASE SUMMARY We present the case of a 54-year-old man with SHC who underwent radical segmental hepatectomy,which relapsed 4 mo after surgery due to lymphatic metastasis in the porta hepatis.Although a second surgery was performed,new metastasis developed in the mediastinal lymph nodes.Therefore,sorafenib and lenvatinib were sequentially administered as first-and second-line systemic therapies,respectively.However,progressive disease was confirmed based on a recurrent hepatic lesion and new metastatic lesion in the abdominal cavity.Percutaneous transhepatic cholangial drainage was performed to alleviate the biliary obstruction.Because the tumor was strongly positive for programmed death-ligand 1,the patient was started on nivolumab.Imaging studies revealed that after two cycles of immunotherapy,the metastatic lesions decreased to undetectable levels.CONCLUSION The patient experienced continuous complete remission for 8 mo.Immune checkpoint inhibitors are useful for the treatment of advanced SHC.
基金Supported by the National Natural Science Foundation of China(No.81300758,No.81700837)Department of Science and Technology,Hunan(No.2015TP2007)
文摘AIM: To explore the clinical feature and genetic etiology of a Chinese Knobloch syndrome family. METHODS: Ocular examinations and magnetic resonance imagings (MRIs) were performed on the family. Whole exome sequencing was conducted on the two patients. Sanger sequencing was utilized to validate the presence of variation in the family as well as in 100 normal controls. Real-time uantitative polymerase chain reaction (PCR) was used to detect the expression level of COL18A1 in peripheral blood lymphocytes of the patients and normal carriers. RESULTS: The affected subjects presented with vision loss, exotropia, cataracts, retinal detachment, and other complications. A homozygous c.4759_4760delCT (p.Leu1587ValfsX72) mutation (rs398122391) in COL18A1 was identified in the two patients, cosegregating with the phenotypes, and did not be detected in 100 normal controls. This mutation caused significant decreased expression of COL18A1 mRNA in the patients. CONCLUSION: The findings strongly indicate that this mutation is the disease-causing mutation. Moreover, this is the first Knobloch syndrome pedigree reported in the Chinese population.
基金supported by the National Natural Science Foundation of China(Grants No.41571455 and 51578115)the Basic Science Research Fund of Northeastern University(Grant No.N160104004)
文摘The concentration of total nitrogen(TN) is reported to vary between 20 and 35 mg/L in domestic wastewater. In raw wastewater, ammonia nitrogen eNHt4-NT is the main nitrogen form, accounting for 70%e82% of the TN concentration. Organic nitrogen, nitrite nitrogen eNOà2-NT,and nitrate nitrogen eNOà3-NT are present as well. For years, due to the lack of regulatory limits on nitrogen concentration in surface waters,nitrogen from secondary effluent has posed a significant threat to the health of aquatic ecosystems. Researchers have made substantial efforts to reduce the nitrogen concentration in secondary effluent. As a kind of advanced wastewater treatment technology, the subsurface infiltration(SI)system has been widely used, owing to its advantages, which include low operation cost, easy maintenance, and low energy consumption. This review discusses the fate of various forms of nitrogen in SI treatment, including organic nitrogen, NHt4-N, NOà2-N, and NOà3-N. Major biological processes involved in nitrogen removal and the main factors influencing its transformation are suggested. Finally, it is shown that ammonification followed by nitrification-denitrification plays a major role in nitrogen removal. Further research needs to focus on the emission characteristics of gaseous nitrogen(generated from the nitrification, denitrification, and completely autotrophic nitrogen-removal over nitrite(CANON) processes) with respect to their greenhouse effects.
文摘AIM:To introduce a novel approach in removal of anterior chamber angle foreign body(ACFB) using a prism contact lens and 23-gauge foreign body forceps.METHODS:Data of 42 eyes of 42 patients who had undergone removal of ACFB using a prism contact lens and 23-gauge foreign body forceps from January 2008 to October 2013 were collected and analyzed. Twenty eyes in group A received the conventional approach by using toothed forceps through corneal limbus incision, and 22 eyes in group B underwent the novel method through the opposite corneal limbus incision. RESULTS:The success rate of ACFB once removal was 75%(15/20) in group A, and 100%(22/22) in group B. The average operation time of group A was significantly longer compared with group B(34.9±9.88 min vs 22.13±8.85min; P〈0.05). The average size of corneal limbus incision in group A was significantly larger than that of group B(4.85±1.89 mm vs 3.95±1.17 mm; P〈0.05). The corneal limbus incision suturing were conducted in all eyes in group A, and only 5 eyes in group B. CONCLUSION:Removal of ACFB using a prism contact lens and 23-gauge foreign body forceps is a safer, more effective, and convenient technique compared with the conventional approach.
基金This work was supported by the National Key Research and Development Program of China under Grant No.2021YFB0300600the National Natural Science Foundation of China under Grant Nos.92270206,T2125013,62032023,61972377,T2293702,and 12274360+2 种基金the Chinese Academy of Sciences Project for Young Scientists in Basic Research under Grant No.YSBR-005the Network Information Project of Chinese Academy of Sciences under Grant No.CASWX2021SF-0103the Key Research Program of Chinese Academy of Sciences under Grant No.ZDBSSSW-WHC002.
文摘The growing demand for semiconductor devices simulation poses a big challenge for large-scale electronic structure calculations.Among various methods,the linearly scaling three-dimensional fragment(LS3DF)method exhibits excellent scalability in large-scale simulations.Based on algorithmic and system-level optimizations,we propose a highly scalable and highly efficient implementation of LS3DF on a domestic heterogeneous supercomputer equipped with acceler-ators.In terms of algorithmic optimizations,the original all-band conjugate gradient algorithm is refined to achieve faster convergence,and mixed precision computing is adopted to increase overall efficiency.In terms of system-level optimiza-tions,the original two-layer parallel structure is replaced by a coarse-grained parallel method.Optimization strategies such as multi-stream,kernel fusion,and redundant computation removal are proposed to increase further utilization of the com-putational power provided by the heterogeneous machines.As a result,our optimized LS3DF can scale to a 10-million sili-con atoms system,attaining a peak performance of 34.8 PFLOPS(21.2% of the peak).All the improvements can be adapt-ed to the next-generation supercomputers for larger simulations.
文摘Purpose: Un displaced subtle ligamentous Lisfranc injuries are easy to miss or underestimate, and many cases are treated without surgical fixation. It has not yet widely known whether conservative treatment for undisplaced subtle ligamentous Lisfranc injuries may lead to a poor outcome. The purpose of this study is to compare the outcomes of conservative versus surgical management (percutaneous position screw) of undisplaced subtle ligamentous Lisfranc injury. Methods: We analysed 61 cases in this retrospective study, including 38 males and 23 females. Forty-one patients were managed conservatively, while 20 patients received surgical treatment involving minimal invasive percutaneous pos让ion screw. American orthopaedic foot &ankle society (AOFAS), foot function index (FFI, including FFI disability, FFl pain score and activity limitation scale) scores, Maryland foot score and short form-36 (SF-36) were recorded and compared after a follow-up of 10-16 months (average 12.3). Results: Patients in the surgical management group had higher scores in all evaluation methods (p < 0.05). The complications in the conservative management group had higher incidenee, mainly including secondary diastasis (34.1% vs. 5.0%), joint stiffness after 3 months (82.9% vs. 0%), and secondary arthrodesis (12.2% vs. 0%). The highest rate of complication in surgical management group was temporary forefoot pain (55.0%). Conclusion: The results of this study suggest that the outcomes of the surgical management with percutaneous position screw fixation are better than the conservative management to treat undisplaced subtle ligamentous Lisfranc injuries. This study can serve as a resource for orthopaedic surgeons in recog nizing and man aging such injuries.
基金supported by the National Key R&D Program of China(Grant No.2018YFB1702504)the National Natural Science Foundation of China(Grant Nos.52179121,51879284)+3 种基金the State Key Laboratory of Simulations and Regulation of Water Cycle in River Basin,China(Grant No.SKL2022ZD05)the IWHR Research&Development Support Program,China(Grant No.GE0145B012021)the Natural Science Foundation of Shaanxi Province,China(Grant No.2021JLM-50)the National Key R&D Program of China(Grant No.2022YFE0200400).
文摘This review summarizes the research outcomes and findings documented in 45 journal papers using a shared tunnel boring machine(TBM)dataset for performance prediction and boring efficiency optimization using machine learning methods.The big dataset was col-lected during the Yinsong water diversion project construction in China,covering the tunnel excavation of a 20 km-section with 199 items of monitoring metrics taken with an interval of one second.The research papers were the result of a call for contributions during a TBM machine learning contest in 2019 and covered a variety of topics related to the intelligent construction of TBM.This review com-prises two parts.Part I is concerned with the data processing,feature extraction,and machine learning methods applied by the contrib-utors.The review finds that the data-driven and knowledge-driven approaches in extracting important features applied by various authors are diversified,requiring further studies to achieve commonly accepted criteria.The techniques for cleaning and amending the raw data adopted by the contributors were summarized,indicating some highlights such as the importance of sufficiently high fre-quency of data acquisition(higher than 1 second),classification and standardization for the data preprocessing process,and the appro-priate selections of features in a boring cycle.The review finds that both supervised and unsupervised machine learning methods have been utilized by various researchers.The ensemble and deep learning methods have found wide applications.Part I highlights the impor-tant features of the individual methods applied by the contributors,including the structures of the algorithm,selection of hyperparam-eters,and model validation approaches.
基金supported by grants from the National Key R&D Program of China(Grant No.2018YFB1702504)the National Natural Science Foundation of China(Grant Nos.52179121,51879284)+3 种基金the State Key Laboratory of Simulations and Regulation of Water Cycle in River Basin,China(Grant No.SKL2022ZD05)the IWHR Research&Development Support Program,China(Grant No.GE0145B012021)the Natural Science Foundation of Shaanxi Province,China(Grant No.2021JLM-50)the National Key R&D Program of China(Grant No.2022YFE0200400).
文摘This review discusses the application scenarios of the machine learning-supported performance prediction and the optimization effi-ciency of tunnel boring machines(TBMs).The rock mass quality ratings,which are based on the Chinese code for geological survey,were used to provide"labels"suitable for supervised learning.As a result,the generation of machine prediction for rock mass grades reason-ably agreed with the ground truth documented in geological maps.In contrast,the main operational parameters,i.e.,thrust and torque,can be reasonably predicted based on historical data.Consequently,18 collapse sections of the Yinsong project have been successfully predicted by several researchers.Preliminary studies on the selection of the optimal penetration rate and cost were conducted.This review also presents a summary of the main achievements in response to the initiatives of the Lotus Pool Contest in China.For the first time,large and well-documented TBM performance data has been shared for joint scientific research.Moreover,the review discusses the technical problems that require further study and the perspectives in the future development of intelligent TBM construction based on big data and machine learning.
文摘The performance of a recycling process for CO_(2) capture and utilization of exhaust gas in the steelmaking plant was reported.A facility capable of capturing CO_(2) at 3200 m^(3)/h was established in the steelmaking plant,resulting in the CO_(2) production of 50,000 t/a.The CO_(2) concentration of the exhaust gas from the lime kiln increased from 25.0 to 99.8 vol.%using the comprehensive method of the pressure swing adsorption and cryogenic separation.The captured and purified CO_(2) was successfully applied in the converter process by the top blowing and bottom blowing.The utilization of CO_(2) was 3.5 m^(3)/t through these two modes.After optimizing parameters of CO_(2)-O_(2) mixed top blowing,the value of[C]×[O]and the content of TFe in slag were reduced by 1.33×10-4 and 1.27%,respectively,and the dephosphorization rate of the molten steel increased by 2.31%.For the CO_(2) bottom blowing,the[N]content in the molten steel was significantly reduced by 5.7×10^(-6).
基金financially supported by the National Natural Science Foundation of China(Nos.51302138 and 21663001)the Western Light Talent Training Program of Chinese Academy of Sciences。
文摘Dense nano-grained Ni_(0.7)Mn_(2.3O4) negative temperature coefficient(NTC) thermistors were fabricated by a novel two-step sintering approach that combines rapid sintering and principle of conventional two-step sintering technique.Samples were sintered at 1042℃ for 30 s in the first rapid step and then at 850-950℃ for 20 h in the second soaking step.Crystal phase,microstructure and electrical properties of sintered samples were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),resistance temperature relationship and aging performance.Sintered samples show a single-phase cubic spinel structure and indicate a high relative density ranging from 84% to 91% of the theoretical density.Moreover,average grain sizes of sintered samples under SEM are distributed between 254 and 570 nm.Meanwhile,the resistivity and the aging coefficient significantly decrease when soaking sintering temperature rises.In addition,the obtained material constant(B) ranges from 3931 to 3981 K.Ni_(0.7)Mn_(2.3)O_(4)-3(soaking at 900℃) and Ni_(0.7)Mn_(2.3O4)-4(soaking at 950℃) present little aging behavior,implying great electrical stability.