In this study,AZ31 Mg alloy sheets were processed by a severe plastic deformation(SPD)technique called forging-bending repeated deformation(FBRD).The effect on the microstructure and microhardness of AZ31 Mg alloy thr...In this study,AZ31 Mg alloy sheets were processed by a severe plastic deformation(SPD)technique called forging-bending repeated deformation(FBRD).The effect on the microstructure and microhardness of AZ31 Mg alloy through FBRD was investigated with increasing temperature treatment and a 90°cross route.The results reveal that the effective strain increases with the number of passes.The flow uniformity is effectively enhanced due to alterations in shear deformation direction.After four passes of deformation,the average grain size is refined by 79.3%compared to the initial specimen.The grain refinement mechanism predominantly originates from the synergistic effects of discontinuous dynamic recrystallization(DDRX),continuous dynamic recrystallization(CDRX),and twinning-induced recrystallization(TDRX).The formation of{1012}extension twins(ET)significantly contributes to coarse grain subdivision and plastic deformation coordinated.Furthermore,pyramidal<c+a>slip activation effectively enhances the plasticity of Mg alloys.By post four-pass processing,the alloy exhibits a microhardness of 81.9HV,primarily governed by fine grain strengthening and dislocation strengthening mechanisms.展开更多
The reuse of green sand in casting production is hindered by the accumulation of oolitic deposits,primarily composed of clay binder with surface degradation,which may adversely affect the the moulding sand performance...The reuse of green sand in casting production is hindered by the accumulation of oolitic deposits,primarily composed of clay binder with surface degradation,which may adversely affect the the moulding sand performance.Currently,there is a lack of standardized methods for quantifying the oolitic content.Accurate measurement of oolitic content is of great significance to the reuse of green sand.Attempts to determine oolitic content using potassium hydroxide(KOH)and phosphoric acid(H_(3)PO_(4))methods encounter challenges due to their excessive reactions with SiO_(2) in the sand.In this study,an improved method for measuring the oolitic content of green sand with repeated approximations was proposed.This method judges the chemical activity of the sample surface through the change of its mass to accurately obtain the mass of the reaction oolitic deposits.The test result of the used sand samples from the foundry shows that the oolitic deposits are completely removed after reacting with KOH solution three times at 300℃ for 20 min.SEM and EDS also show that after three times of reactions,the surface of green sand becomes smooth and the content of Al-containing oolitic deposits is very low.This indicates that the method can accurately control the extent of the reaction.Implementation of this method at Huangshi Dongbei Casting Co.,Ltd.has yielded consistent and reliable test results,effectively mirroring variations in green sand oolitic content on the production line.This new method is expected to be widely adopted to improve the efficiency and quality of reused green sand in casting operations.展开更多
In repeated zero-sum games,instead of constantly playing an equilibrium strategy of the stage game,learning to exploit the opponent given historical interactions could typically obtain a higher utility.However,when pl...In repeated zero-sum games,instead of constantly playing an equilibrium strategy of the stage game,learning to exploit the opponent given historical interactions could typically obtain a higher utility.However,when playing against a fully adaptive opponent,one would have dificulty identifying the opponent's adaptive dynamics and further exploiting its potential weakness.In this paper,we study the problem of optimizing against the adaptive opponent who uses no-regret learning.No-regret learning is a classic and widely-used branch of adaptive learning algorithms.We propose a general framework for online modeling no-regret opponents and exploiting their weakness.With this framework,one could approximate the opponent's no-regret learning dynamics and then develop a response plan to obtain a significant profit based on the inferences of the opponent's strategies.We employ two system identification architectures,including the recurrent neural network(RNN)and the nonlinear autoregressive exogenous model,and adopt an efficient greedy response plan within the framework.Theoretically,we prove the approximation capability of our RNN architecture at approximating specific no-regret dynamics.Empirically,we demonstrate that during interactions at a low level of non-stationarity,our architectures could approximate the dynamics with a low error,and the derived policies could exploit the no-regret opponent to obtain a decent utility.展开更多
BACKGROUND Repeated application of the Pringle maneuver is a key obstacle to safe minimally invasive repeat liver resection(MISRLR).However,limited technical guidance is available.AIM To study the utility of newly dev...BACKGROUND Repeated application of the Pringle maneuver is a key obstacle to safe minimally invasive repeat liver resection(MISRLR).However,limited technical guidance is available.AIM To study the utility of newly developed Pringle taping method guided by liver surface in MISRLR.METHODS We retrospectively reviewed 72 cases of MISRLR performed by a single surgeon at two centers from August 2015 to July 2024.Beginning in October 2019,a liver surface-guided encirclement of hepatoduodenal ligament(LSEH)was used for repeat Pringle taping.Perioperative outcomes including Pringle taping success,operative time,blood loss,conversion rate,morbidity,and mortality were assessed.RESULTS Laparoscopic and robotic approaches were used in 63 patients and 9 patients,respectively.The median operative time,blood loss,and hospital stay were 331.5 minutes,70 mL,and 8 days,respectively.Open conversion occurred in two cases(2.8%)due to severe adhesions and right renal vein injury.Clavien-Dindo grade≥III complications occurred in 5.6%of cases with no mortality.Anti-adhesion barriers were used in 54 patients(75.0%).LSEH was attempted in 57 cases,improving Pringle taping success from 33.0%to 91.4%(P<0.001).LSEH succeeded in all patients with prior open liver resection(n=11).Among 6 patients in whom LSEH failed,3 patients(50.0%)had undergone a third liver resection,and 1 patient had a history of distal gastrectomy with choledochoduodenostomy.CONCLUSION The newly developed LSEH technique for Pringle taping in MISRLR was feasible,enhancing safety and reproducibility even in patients with a history of open liver resection.展开更多
The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRT...The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRTM and relief-DEM, which was derived from aerial topographic map, were used to evaluate the influence of external DEM. The results show that SRTM could not fully compensate the complex topography of the research area. The corner reflectors installed during the acquisition of SAR dataset were used to estimate the accuracy of geocoding. The terrain corrected geocoding results based on relief-DEM were much better than using SRTM, with the root mean square error（RMSE） being 6.35 m in X direction and 11.65 m in Y direction（both in UTM projection）, around one pixel of the multilooked intensity image to be geocoded. For PSI technique, the results from time-series analysis of multi-baseline differential interferograms were integrated to restrict only persistent scatterer candidates near the boundary of subsiding area for regression analysis. The results demonstrate that PSI can refine the boundary of subsidence, which could then be used to derive some angular parameters to help people to learn the law of subsidence caused by repeated excavation in this area.展开更多
Both the repeated triaxial test （RTT） and the Hamburg wheel tracking test （HWTT） are adopted to evaluate the high temperature performance of the stone mastic asphalt （SMA） and the mastic asphalt （MA）. The corr...Both the repeated triaxial test （RTT） and the Hamburg wheel tracking test （HWTT） are adopted to evaluate the high temperature performance of the stone mastic asphalt （SMA） and the mastic asphalt （MA）. The correlation of the permanent deformations of the MA and the correlation of the deformation developments of the SMA between the two tests are analyzed, respectively. Results show that both the two tests can effectively identify the high temperature performance of mixtures, and the correlation between the final results of the two tests as well as that between the deformation developments of the two tests are excellent with R20.9. In order to further prove the correlation, viscoelastic parameters estimated from the RTT results is used to simulate the rutting development in the HWTT slabs by the finite element method （FEM）. Results indicate that the correlation between the two tests is significant with errors less than 10%. It is suitable to predict the rutting development with the viscoelastic parameters obtained from the RTT.展开更多
The series-wound dashpot of the Burgers model is modified by introducing the strain hardening parameter, and the new model is considered as a combination of the modified dashpot and the Van Der Poel model. The cyclica...The series-wound dashpot of the Burgers model is modified by introducing the strain hardening parameter, and the new model is considered as a combination of the modified dashpot and the Van Der Poel model. The cyclical pulse load consisting of a haversine load time and a rest period is adopted to simulate the actual vehicle load, and the permanent strain model under the repeated load is derived from the rheological and viscoelastic theories. Subsequently, the model is validated by the results of uniaxial repeated load permanent deformation tests of three asphalt mixtures. It is indicated that the proportion of residual viscoelastic strain to permanent strain decreases gradually with the load cycles, and only accounts for 2% to 3% during most of the loading period. If the rest period is long, the residual viscoelastic strain is little. The rest period of the actual vehicle load may be long enough, so the residual viscoelasticity can be ignored and the simplified model can be obtained. The proposed model can well describe the permanent deformation of asphalt mixtures under repeated load.展开更多
A new electrocardiogram(ECG) data compression method is presented.It employs a repeated coding.In this method beat templates are extracted from original signals according to the features of ECG.The data are divided in...A new electrocardiogram(ECG) data compression method is presented.It employs a repeated coding.In this method beat templates are extracted from original signals according to the features of ECG.The data are divided into three parts:beat template,residual and position parameter.The three separate parts are first encoded with LADT,and then use the lossless entropy encoding to maintain a low level of reconstructed waveform distortion.The entropy encoding based on Huffman encoding is employed here as an example.Selections from the MIT BIH arrhythmia database,show that there is substantial improvement in compression ratio (CR) over other single and simple compression methods for comparable percent root mean square difference(PRD).展开更多
Carbendazim, a systemic benzimidazole fungicide, is applied repeatedly to control plant diseases including soilborne diseases, over a growing season. Studies were carried out under laboratory conditions to assess the ...Carbendazim, a systemic benzimidazole fungicide, is applied repeatedly to control plant diseases including soilborne diseases, over a growing season. Studies were carried out under laboratory conditions to assess the effects of repeated carbendazim applications on its persistence and microbial community in soil. The results indicate that dissipation of carbendazim in soil was accelerated with its application frequency. The degradation rate constant of carbendazim was increased significantly from 0.074 d-1 to 0.79 d-1. The corresponding half-life was shorten markedly from 9.3 d to 0.9 d after four repeated applications. No significant inhibitory effect of carbendazim on soil microbial utilization of the carbon sources was observed after first treatment, but a slight increase in average well color development （AWCD） was shown after second, third, and fourth applications. It suggested that soil microorganisms become adapted to carbendazim after repeated application. Simpson and Shannon indexes of soil microbial community from carbendazim treated soil were also similar to those from the control soil, indicating that the richness and dominant character of soil microorganisms remain unchangeable after repeated application. However, after first, second, and third addition of carbendazim, McIntosh indexes on day 21 were significantly higher compared with the control, suggesting that balance of soil microorganisms was altered due to the enrichment of the specific carbendazim-adapting strains in soil展开更多
In this study, we compared the effects of repeated freezing/thawing of human sperm by our in-house method of rapid freezing with slow programmable freezing. Sperm samples from 11 normozoospermic subjects were processe...In this study, we compared the effects of repeated freezing/thawing of human sperm by our in-house method of rapid freezing with slow programmable freezing. Sperm samples from 11 normozoospermic subjects were processed through density gradients and divided into three aliquots： non-frozen, rapid freezing and slow programmable freezing. Sperm in the rapid freezing group had better motility and viability than those in the slow freezing group （P〈O.01） after the first, second and third cycles of freezing/thawing, but there was no difference in morphology. In the second experiment, rapid freezing was repeated three times in 20 subjects. The samples from each thawing cycle were evaluated for DNA fragmentation using the alkaline comet assay. DNA fragmentation began to increase considerably after the second cycle of freezing/thawing, but to a level that was not clinically important. In the third experiment, rapid freezing was done repeatedly in 10 subjects, until no motile sperm were observed after thawing. The median number of repeated freezing/thawing that yielded no motile sperm was seven （range： 5-8, mean： 6.8）. In conclusion, we demonstrated that repeated freezing/thawing of processed semen using our rapid freezing method gave better results than standard slow programmable freezing. This method can help maximize the usage of precious cryopreserved sperm samples in assisted reproduction technology.展开更多
The paper attempts to represent a case of repeated failures on a high cut slope due to multi-excavation. The characteristics of each failure induced by excavation are analyzed through geological investigation, and the...The paper attempts to represent a case of repeated failures on a high cut slope due to multi-excavation. The characteristics of each failure induced by excavation are analyzed through geological investigation, and then a geological model at different failure stages is proposed. The geological analysis shows that the excavation-induced repeated failures are related to the exposure of the weak bedding plane and the toe unloading of the cut slope, Numerical modeling is conducted based on a sequential method, taking into account the main failure stages of cut slope. The simulation results fairly coincide with the practical phenomena observed in field. It is shown that the decrease in normal stress of displaced mass on cut slope will induce the increase in shear stress in bedding planes and that at the toe of the cut slope. The released stress leads to repeated gravitational instabilities of cut slope due to the decrease in normal stress and the increase in shear stress along the bedding planes of mudstone.展开更多
BACKGROUND Polyacrylamide hydrogel(PAAG)injections were once common in breast augmentation and have been prohibited for augmentation mammaplasty in China since a large number of patients who underwent breast augmentat...BACKGROUND Polyacrylamide hydrogel(PAAG)injections were once common in breast augmentation and have been prohibited for augmentation mammaplasty in China since a large number of patients who underwent breast augmentation with PAAG injections have continued to seek medical advice as a result of related complications.Among all these complications,distant migration is relatively rare.CASE SUMMARY A 49-year-old female presented at the hospital with a one-year history of a vulvar lump.The sonography of the lump showed several subcutaneous fluid-filled regions from the left vulva to the pubic symphysis,which suggested possible fat liquefaction.An enhanced magnetic resonance imaging(MRI)revealed a cystic area,which was considered a benign lesion.Intraoperative observations showed that the mass did not have an obvious capsule,the subcutaneous tissue presented as a cavity,and some yellow material came out of this cavity.A culture of the drainage did not show bacterial contamination.Histopathology revealed a foreign body granuloma.After resection and closed drainage,lumps were successively observed in the left lower abdomen and the bilateral hypochondriac region with infections.Sonography found that the hypoechoic areas in the bilateral hypochondriac region seemed continuous with deep in the breasts.The patient reported that she had undergone surgery with PAAG injections 20 years ago after she was repeatedly asked about her past history.Finally,a diagnosis of distant migration of PAAG was made.CONCLUSION PAAG gel can migrate after long periods of time.A diagnosis should not be limited to the area where the symptom develops.展开更多
In China, most oil fields are continental sedimentation with strong heterogeneity, which on one side makes the reservoir prospecting and development more difficult, but on the other side provides more space for search...In China, most oil fields are continental sedimentation with strong heterogeneity, which on one side makes the reservoir prospecting and development more difficult, but on the other side provides more space for searching residual oil in matured fields. Time-lapse seismic reservoir monitoring technique is one of most important techniques to define residual oil distribution. According to the demand for and development of time-lapse seismic reservoir monitoring in China, purposeless repeated acquisition time-lapse seismic data processing was studied. The four key steps in purposeless repeated acquisition time-lapse seismic data processing, including amplitude-preserved processing with relative consistency, rebinning, match filtering and difference calculation, were analyzed by combining theory and real seismic data processing. Meanwhile, quality control during real time-lapse seismic processing was emphasized.展开更多
Objective The present study was undertaken to evaluate the subchronic toxicity of lanthanum and to determine the no observed adverse effect level（NOAEL）,which is a critical factor in the establishment of an acceptab...Objective The present study was undertaken to evaluate the subchronic toxicity of lanthanum and to determine the no observed adverse effect level（NOAEL）,which is a critical factor in the establishment of an acceptable dietary intake（ADI）.Methods In accordance with the Organization for Economic Co-operation and Development（OECD） testing guidelines,lanthanum nitrate was administered once daily by gavage to Sprague-Dawley（SD） rats at dose levels of 0,1.5,6.0,24.0,and 144.0 mg/kg body weight（BW） per day for 90 days,followed by a recovery period of 4 weeks in the 144.0 mg/kg BW per day and normal control groups.Outcome parameters were mortality,clinical symptoms,body and organ weights,serum chemistry,and food consumption,as well as ophthalmic,urinary,hematologic,and histopathologic indicators.The benchmark dose（BMD） approach was applied to estimate a point of departure for the hazard risk assessment of lanthanum.Results Significant decreases were found in the 144.0 mg/kg BW group in the growth index,including body weight,organ weights,and food consumption.This study suggests that the NOAEL of lanthanum nitrate is 24.0 mg/kg BW per day.Importantly,the 95% lower confidence value of the benchmark dose（BMDL） was estimated as 9.4 mg/kg BW per day in females and 19.3 mg/kg BW per day in males.Conclusion The present subchronic oral exposure toxicity study may provide scientific data for the risk assessment of lanthanum and other rare earth elements（REEs）.展开更多
The exciting source of the active source repeated monitoring is located in the Xiliushui Reservoir in Zhangye,Gansu Province. The system began operating normally on July 9,2015,and we had completed a period of 40 days...The exciting source of the active source repeated monitoring is located in the Xiliushui Reservoir in Zhangye,Gansu Province. The system began operating normally on July 9,2015,and we had completed a period of 40 days of continuous excitation experiment before November 10,2015. Our results reveal that the airgun source has good consistency and repeatability,and the detective system of active source can record signal clearly. The construction of active source repeated exploration projects has achieved some results,which can provide valuable experience for the research of active source repeated exploration. The observation data we obtained makes it possible to follow the temporal and spatial variations of the deep structure of the Qilian Mountain areas.展开更多
Long-term gonadotropin-releasing hormone agonist（Gn RHa） administration before in vitro fertilization（IVF）/intracytoplasmic sperm injection（ICSI） in infertile women with endometriosis or adenomyosis significantl...Long-term gonadotropin-releasing hormone agonist（Gn RHa） administration before in vitro fertilization（IVF）/intracytoplasmic sperm injection（ICSI） in infertile women with endometriosis or adenomyosis significantly enhanced the chances of pregnancy in both fresh and frozen embryo transfer cycles. We hypothesized that long-term Gn RHa treatment might also be beneficial for the idiopathic repeated implantation failure（RIF） patients. In the 21 patients receiving Gn RHa and hormone replacement therapy（G-HRT） protocols for frozen embryo transfer, their data were compared with those of the 56 of frozen/fresh cycles they had previously undergone（previous protocols）. Comparison showed that the finial results were significantly better with G-HRT protocols than with their previous protocols, with pregnancy rate, clinical pregnancy rate, implantation rate and on-going pregnancy rate being 70%, 60%, 40% and 38% respectively with G-HRT protocols, against 17%, 11%, 6.3% and 5% with previous protocols. The results showed that hormonally controlled endometrial preparation with prior Gn RHa suppression could be used for patients who had experienced repeated failures of IVF treatment despite having morphologically optimal embryos, and the treatment may help increase the receptivity of the endometrium in these patients.展开更多
The feasibility of using different generations of recycled fine aggregate（RFA） in structural concrete in a chloride environment was evaluated by studying the performance of the RFA and the corresponding concrete. Th...The feasibility of using different generations of recycled fine aggregate（RFA） in structural concrete in a chloride environment was evaluated by studying the performance of the RFA and the corresponding concrete. The different generations of RFA were recycled by following the cycle of ‘concrete-waste concrete-fine aggregate-concrete＇. The properties of three generations of repeatedly recycled fine aggregate（RRFA） were systematically investigated, and we focused on the compressive strength and splitting tensile strength and chloride ion permeability of the related structural concretes with 25%, 75%, and 100% replacement of natural fine aggregates with RFA. The results indicated that the quality of RRFA presents a trend of slow deterioration, but the overall performance of all RRFA still fulfils the quality requirements of recycled fine aggregate for structural concrete. All RRFA concretes achieved the target compressive strength of 40 MPa after 28 days except for the second generation of the recycled aggregate concrete and the third generation of the recycled aggregate concrete with 100% replacement, and all the concrete mixes achieved the target compressive strength after 90 days. The insights obtained in this study demonstrate the feasibility of using at least three generations of RRFA for the production of normal structural concrete with a design service life of 100 years in a chloride environment.展开更多
Animals always seek rewards and the related neural basis has been well studied. However, what happens when animals fail to get a reward is largely unknown,although this is commonly seen in behaviors such as predation....Animals always seek rewards and the related neural basis has been well studied. However, what happens when animals fail to get a reward is largely unknown,although this is commonly seen in behaviors such as predation. Here, we set up a behavioral model of repeated failure in reward pursuit(RFRP) in Drosophila larvae. In this model, the larvae were repeatedly prevented from reaching attractants such as yeast and butyl acetate, before finally abandoning further attempts. After giving up, they usually showed a decreased locomotor speed and impaired performance in light avoidance and sugar preference,which were named as phenotypes of RFRP states. In larvae that had developed RFRP phenotypes, the octopamine concentration was greatly elevated, while tbh mutants devoid of octopamine were less likely to develop RFRP phenotypes, and octopamine feeding efficiently restored such defects. By down-regulating tbh in different groups of neurons and imaging neuronal activity, neurons that regulated the development of RFRP states and the behavioral exhibition of RFRP phenotypes were mapped to a small subgroup of non-glutamatergic and glutamatergic octopaminergic neurons in the central larval brain. Our results establish a model for investigating the effect of depriving an expected reward in Drosophila and provide a simplified framework for the associated neural basis.展开更多
DInSAR technology was used to monitor subsidence caused by underground coal mining activities in mountainous area, with multi source SAR data, including 8 EnviSAT C-band and 4 ALOS L-band, and 4 programmed TerraSAR-X ...DInSAR technology was used to monitor subsidence caused by underground coal mining activities in mountainous area, with multi source SAR data, including 8 EnviSAT C-band and 4 ALOS L-band, and 4 programmed TerraSAR-X dataset. The results revealed that 2-pass DInSAR technique sometimes failed to retrieve the mining-caused subsidence due to spatial and/or temporal de-correlation. We also noticed that there existed residual topographic phase after the compensation with SRTM DEM, which could almost overwhelm the subsidence information when the perpendicular baseline was relatively large. Based on the mining materials, analysis was made on the shape of subsidence area. For the well geocoded results from TerraSAR-X, confirmed by GPS surveying results of corner reflectors, we tried to extract the advance distance of influence besides the subsidence area. Due to the big deformation gradient over stopingfaces, the X-band SAR data could not capture the maximum value subsidence revealed by GPS survey in our preliminary results, the same as C-band EnviSAT data. This will turn to be our research subject in the next few months.展开更多
A family of modal methods for computing eigenvector derivatives with repeated roots are directly derived from the constraint generalized inverse technique which is originally formulated by Wang and Hu. Extensions are ...A family of modal methods for computing eigenvector derivatives with repeated roots are directly derived from the constraint generalized inverse technique which is originally formulated by Wang and Hu. Extensions are made to Akgun's method to allow treatment of eigensensitivity with repeated roots for general nondefective systems, and Bernard and Bronowicki's modal expansion approach is expanded to a family of modal methods.展开更多
基金Project(52174362)supported by the National Natural Science Foundation of ChinaProject(2023JJ10020)supported by the Natural Science Foundation of Hunan Province,China+2 种基金Project(2024RC7002)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2024CY2-GJHX-71)supported by the Shaanxi Provincial Key R&D Program,ChinaProject supported by the Yancheng“Talent Plan of Yellow Sea Pearl”for Leading Talent Project,China。
文摘In this study,AZ31 Mg alloy sheets were processed by a severe plastic deformation(SPD)technique called forging-bending repeated deformation(FBRD).The effect on the microstructure and microhardness of AZ31 Mg alloy through FBRD was investigated with increasing temperature treatment and a 90°cross route.The results reveal that the effective strain increases with the number of passes.The flow uniformity is effectively enhanced due to alterations in shear deformation direction.After four passes of deformation,the average grain size is refined by 79.3%compared to the initial specimen.The grain refinement mechanism predominantly originates from the synergistic effects of discontinuous dynamic recrystallization(DDRX),continuous dynamic recrystallization(CDRX),and twinning-induced recrystallization(TDRX).The formation of{1012}extension twins(ET)significantly contributes to coarse grain subdivision and plastic deformation coordinated.Furthermore,pyramidal<c+a>slip activation effectively enhances the plasticity of Mg alloys.By post four-pass processing,the alloy exhibits a microhardness of 81.9HV,primarily governed by fine grain strengthening and dislocation strengthening mechanisms.
基金financially supported by the National Key Research and Development Program of China(Grant No.2022YFB3706800)the National Natural Science Foundation of China(Grant Nos.51905188 and 51775205).
文摘The reuse of green sand in casting production is hindered by the accumulation of oolitic deposits,primarily composed of clay binder with surface degradation,which may adversely affect the the moulding sand performance.Currently,there is a lack of standardized methods for quantifying the oolitic content.Accurate measurement of oolitic content is of great significance to the reuse of green sand.Attempts to determine oolitic content using potassium hydroxide(KOH)and phosphoric acid(H_(3)PO_(4))methods encounter challenges due to their excessive reactions with SiO_(2) in the sand.In this study,an improved method for measuring the oolitic content of green sand with repeated approximations was proposed.This method judges the chemical activity of the sample surface through the change of its mass to accurately obtain the mass of the reaction oolitic deposits.The test result of the used sand samples from the foundry shows that the oolitic deposits are completely removed after reacting with KOH solution three times at 300℃ for 20 min.SEM and EDS also show that after three times of reactions,the surface of green sand becomes smooth and the content of Al-containing oolitic deposits is very low.This indicates that the method can accurately control the extent of the reaction.Implementation of this method at Huangshi Dongbei Casting Co.,Ltd.has yielded consistent and reliable test results,effectively mirroring variations in green sand oolitic content on the production line.This new method is expected to be widely adopted to improve the efficiency and quality of reused green sand in casting operations.
基金the Science and Technology Innovation 2030-"New Generation Artificial Intelligence"Major Project(No.2018AAA0100901)。
文摘In repeated zero-sum games,instead of constantly playing an equilibrium strategy of the stage game,learning to exploit the opponent given historical interactions could typically obtain a higher utility.However,when playing against a fully adaptive opponent,one would have dificulty identifying the opponent's adaptive dynamics and further exploiting its potential weakness.In this paper,we study the problem of optimizing against the adaptive opponent who uses no-regret learning.No-regret learning is a classic and widely-used branch of adaptive learning algorithms.We propose a general framework for online modeling no-regret opponents and exploiting their weakness.With this framework,one could approximate the opponent's no-regret learning dynamics and then develop a response plan to obtain a significant profit based on the inferences of the opponent's strategies.We employ two system identification architectures,including the recurrent neural network(RNN)and the nonlinear autoregressive exogenous model,and adopt an efficient greedy response plan within the framework.Theoretically,we prove the approximation capability of our RNN architecture at approximating specific no-regret dynamics.Empirically,we demonstrate that during interactions at a low level of non-stationarity,our architectures could approximate the dynamics with a low error,and the derived policies could exploit the no-regret opponent to obtain a decent utility.
文摘BACKGROUND Repeated application of the Pringle maneuver is a key obstacle to safe minimally invasive repeat liver resection(MISRLR).However,limited technical guidance is available.AIM To study the utility of newly developed Pringle taping method guided by liver surface in MISRLR.METHODS We retrospectively reviewed 72 cases of MISRLR performed by a single surgeon at two centers from August 2015 to July 2024.Beginning in October 2019,a liver surface-guided encirclement of hepatoduodenal ligament(LSEH)was used for repeat Pringle taping.Perioperative outcomes including Pringle taping success,operative time,blood loss,conversion rate,morbidity,and mortality were assessed.RESULTS Laparoscopic and robotic approaches were used in 63 patients and 9 patients,respectively.The median operative time,blood loss,and hospital stay were 331.5 minutes,70 mL,and 8 days,respectively.Open conversion occurred in two cases(2.8%)due to severe adhesions and right renal vein injury.Clavien-Dindo grade≥III complications occurred in 5.6%of cases with no mortality.Anti-adhesion barriers were used in 54 patients(75.0%).LSEH was attempted in 57 cases,improving Pringle taping success from 33.0%to 91.4%(P<0.001).LSEH succeeded in all patients with prior open liver resection(n=11).Among 6 patients in whom LSEH failed,3 patients(50.0%)had undergone a third liver resection,and 1 patient had a history of distal gastrectomy with choledochoduodenostomy.CONCLUSION The newly developed LSEH technique for Pringle taping in MISRLR was feasible,enhancing safety and reproducibility even in patients with a history of open liver resection.
基金Project(51174191)supported by the National Natural Science Foundation of ChinaProject(2013CB227904)supported by the National Basic Research Program of ChinaProject(2012QNB09)supported by Fundamental Research Funds for the Central Universities,China
文摘The high resolution Terra SAR-X dataset was employed with DIn SAR and persistent scatterer interferometry（PSI） technique for subsidence monitoring in a mountainous area. For DInS AR technique, the generally used SRTM and relief-DEM, which was derived from aerial topographic map, were used to evaluate the influence of external DEM. The results show that SRTM could not fully compensate the complex topography of the research area. The corner reflectors installed during the acquisition of SAR dataset were used to estimate the accuracy of geocoding. The terrain corrected geocoding results based on relief-DEM were much better than using SRTM, with the root mean square error（RMSE） being 6.35 m in X direction and 11.65 m in Y direction（both in UTM projection）, around one pixel of the multilooked intensity image to be geocoded. For PSI technique, the results from time-series analysis of multi-baseline differential interferograms were integrated to restrict only persistent scatterer candidates near the boundary of subsiding area for regression analysis. The results demonstrate that PSI can refine the boundary of subsidence, which could then be used to derive some angular parameters to help people to learn the law of subsidence caused by repeated excavation in this area.
基金The Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (No.6821001005)
文摘Both the repeated triaxial test （RTT） and the Hamburg wheel tracking test （HWTT） are adopted to evaluate the high temperature performance of the stone mastic asphalt （SMA） and the mastic asphalt （MA）. The correlation of the permanent deformations of the MA and the correlation of the deformation developments of the SMA between the two tests are analyzed, respectively. Results show that both the two tests can effectively identify the high temperature performance of mixtures, and the correlation between the final results of the two tests as well as that between the deformation developments of the two tests are excellent with R20.9. In order to further prove the correlation, viscoelastic parameters estimated from the RTT results is used to simulate the rutting development in the HWTT slabs by the finite element method （FEM）. Results indicate that the correlation between the two tests is significant with errors less than 10%. It is suitable to predict the rutting development with the viscoelastic parameters obtained from the RTT.
基金The National Natural Science Foundation of China(No50608006)Program for New Century Excellent Talents in University(NoNCET-07-0120)
文摘The series-wound dashpot of the Burgers model is modified by introducing the strain hardening parameter, and the new model is considered as a combination of the modified dashpot and the Van Der Poel model. The cyclical pulse load consisting of a haversine load time and a rest period is adopted to simulate the actual vehicle load, and the permanent strain model under the repeated load is derived from the rheological and viscoelastic theories. Subsequently, the model is validated by the results of uniaxial repeated load permanent deformation tests of three asphalt mixtures. It is indicated that the proportion of residual viscoelastic strain to permanent strain decreases gradually with the load cycles, and only accounts for 2% to 3% during most of the loading period. If the rest period is long, the residual viscoelastic strain is little. The rest period of the actual vehicle load may be long enough, so the residual viscoelasticity can be ignored and the simplified model can be obtained. The proposed model can well describe the permanent deformation of asphalt mixtures under repeated load.
文摘A new electrocardiogram(ECG) data compression method is presented.It employs a repeated coding.In this method beat templates are extracted from original signals according to the features of ECG.The data are divided into three parts:beat template,residual and position parameter.The three separate parts are first encoded with LADT,and then use the lossless entropy encoding to maintain a low level of reconstructed waveform distortion.The entropy encoding based on Huffman encoding is employed here as an example.Selections from the MIT BIH arrhythmia database,show that there is substantial improvement in compression ratio (CR) over other single and simple compression methods for comparable percent root mean square difference(PRD).
基金supported by the National Natural Sci-ence Foundation of China (No. 30771254)the Zhejiang Provincial Natural Science Foundation (No. Z306260)+2 种基金the National Key Technology R&D Program of China (No.2006BAI09B03)Hi-Tech Research and Development Program (863) of China (No. 2007AA06Z306 )the Program for New Century Excellent Talents in University.
文摘Carbendazim, a systemic benzimidazole fungicide, is applied repeatedly to control plant diseases including soilborne diseases, over a growing season. Studies were carried out under laboratory conditions to assess the effects of repeated carbendazim applications on its persistence and microbial community in soil. The results indicate that dissipation of carbendazim in soil was accelerated with its application frequency. The degradation rate constant of carbendazim was increased significantly from 0.074 d-1 to 0.79 d-1. The corresponding half-life was shorten markedly from 9.3 d to 0.9 d after four repeated applications. No significant inhibitory effect of carbendazim on soil microbial utilization of the carbon sources was observed after first treatment, but a slight increase in average well color development （AWCD） was shown after second, third, and fourth applications. It suggested that soil microorganisms become adapted to carbendazim after repeated application. Simpson and Shannon indexes of soil microbial community from carbendazim treated soil were also similar to those from the control soil, indicating that the richness and dominant character of soil microorganisms remain unchangeable after repeated application. However, after first, second, and third addition of carbendazim, McIntosh indexes on day 21 were significantly higher compared with the control, suggesting that balance of soil microorganisms was altered due to the enrichment of the specific carbendazim-adapting strains in soil
文摘In this study, we compared the effects of repeated freezing/thawing of human sperm by our in-house method of rapid freezing with slow programmable freezing. Sperm samples from 11 normozoospermic subjects were processed through density gradients and divided into three aliquots： non-frozen, rapid freezing and slow programmable freezing. Sperm in the rapid freezing group had better motility and viability than those in the slow freezing group （P〈O.01） after the first, second and third cycles of freezing/thawing, but there was no difference in morphology. In the second experiment, rapid freezing was repeated three times in 20 subjects. The samples from each thawing cycle were evaluated for DNA fragmentation using the alkaline comet assay. DNA fragmentation began to increase considerably after the second cycle of freezing/thawing, but to a level that was not clinically important. In the third experiment, rapid freezing was done repeatedly in 10 subjects, until no motile sperm were observed after thawing. The median number of repeated freezing/thawing that yielded no motile sperm was seven （range： 5-8, mean： 6.8）. In conclusion, we demonstrated that repeated freezing/thawing of processed semen using our rapid freezing method gave better results than standard slow programmable freezing. This method can help maximize the usage of precious cryopreserved sperm samples in assisted reproduction technology.
基金Supported by the National Natural Science Foundation of China(41072213 and 40801212)the Opening Fund of Key Laboratory of Mechanics on Disaster and Environment in Western China, Lanzhou University(201207)
文摘The paper attempts to represent a case of repeated failures on a high cut slope due to multi-excavation. The characteristics of each failure induced by excavation are analyzed through geological investigation, and then a geological model at different failure stages is proposed. The geological analysis shows that the excavation-induced repeated failures are related to the exposure of the weak bedding plane and the toe unloading of the cut slope, Numerical modeling is conducted based on a sequential method, taking into account the main failure stages of cut slope. The simulation results fairly coincide with the practical phenomena observed in field. It is shown that the decrease in normal stress of displaced mass on cut slope will induce the increase in shear stress in bedding planes and that at the toe of the cut slope. The released stress leads to repeated gravitational instabilities of cut slope due to the decrease in normal stress and the increase in shear stress along the bedding planes of mudstone.
基金Supported by Zhejiang Provincial Medical and Health Platform Project,No.2018275889
文摘BACKGROUND Polyacrylamide hydrogel(PAAG)injections were once common in breast augmentation and have been prohibited for augmentation mammaplasty in China since a large number of patients who underwent breast augmentation with PAAG injections have continued to seek medical advice as a result of related complications.Among all these complications,distant migration is relatively rare.CASE SUMMARY A 49-year-old female presented at the hospital with a one-year history of a vulvar lump.The sonography of the lump showed several subcutaneous fluid-filled regions from the left vulva to the pubic symphysis,which suggested possible fat liquefaction.An enhanced magnetic resonance imaging(MRI)revealed a cystic area,which was considered a benign lesion.Intraoperative observations showed that the mass did not have an obvious capsule,the subcutaneous tissue presented as a cavity,and some yellow material came out of this cavity.A culture of the drainage did not show bacterial contamination.Histopathology revealed a foreign body granuloma.After resection and closed drainage,lumps were successively observed in the left lower abdomen and the bilateral hypochondriac region with infections.Sonography found that the hypoechoic areas in the bilateral hypochondriac region seemed continuous with deep in the breasts.The patient reported that she had undergone surgery with PAAG injections 20 years ago after she was repeatedly asked about her past history.Finally,a diagnosis of distant migration of PAAG was made.CONCLUSION PAAG gel can migrate after long periods of time.A diagnosis should not be limited to the area where the symptom develops.
文摘In China, most oil fields are continental sedimentation with strong heterogeneity, which on one side makes the reservoir prospecting and development more difficult, but on the other side provides more space for searching residual oil in matured fields. Time-lapse seismic reservoir monitoring technique is one of most important techniques to define residual oil distribution. According to the demand for and development of time-lapse seismic reservoir monitoring in China, purposeless repeated acquisition time-lapse seismic data processing was studied. The four key steps in purposeless repeated acquisition time-lapse seismic data processing, including amplitude-preserved processing with relative consistency, rebinning, match filtering and difference calculation, were analyzed by combining theory and real seismic data processing. Meanwhile, quality control during real time-lapse seismic processing was emphasized.
基金supported by China Food Safety Talent Competency Development Initiative:CFSA 523 Programthe National Natural Science Foundation of China[No.81402683]
文摘Objective The present study was undertaken to evaluate the subchronic toxicity of lanthanum and to determine the no observed adverse effect level（NOAEL）,which is a critical factor in the establishment of an acceptable dietary intake（ADI）.Methods In accordance with the Organization for Economic Co-operation and Development（OECD） testing guidelines,lanthanum nitrate was administered once daily by gavage to Sprague-Dawley（SD） rats at dose levels of 0,1.5,6.0,24.0,and 144.0 mg/kg body weight（BW） per day for 90 days,followed by a recovery period of 4 weeks in the 144.0 mg/kg BW per day and normal control groups.Outcome parameters were mortality,clinical symptoms,body and organ weights,serum chemistry,and food consumption,as well as ophthalmic,urinary,hematologic,and histopathologic indicators.The benchmark dose（BMD） approach was applied to estimate a point of departure for the hazard risk assessment of lanthanum.Results Significant decreases were found in the 144.0 mg/kg BW group in the growth index,including body weight,organ weights,and food consumption.This study suggests that the NOAEL of lanthanum nitrate is 24.0 mg/kg BW per day.Importantly,the 95% lower confidence value of the benchmark dose（BMDL） was estimated as 9.4 mg/kg BW per day in females and 19.3 mg/kg BW per day in males.Conclusion The present subchronic oral exposure toxicity study may provide scientific data for the risk assessment of lanthanum and other rare earth elements（REEs）.
基金sponsored by the Special Fund for Earthquake Scientific Research in the Public Welfare of CEA(201308011)
文摘The exciting source of the active source repeated monitoring is located in the Xiliushui Reservoir in Zhangye,Gansu Province. The system began operating normally on July 9,2015,and we had completed a period of 40 days of continuous excitation experiment before November 10,2015. Our results reveal that the airgun source has good consistency and repeatability,and the detective system of active source can record signal clearly. The construction of active source repeated exploration projects has achieved some results,which can provide valuable experience for the research of active source repeated exploration. The observation data we obtained makes it possible to follow the temporal and spatial variations of the deep structure of the Qilian Mountain areas.
基金supported by grants from the National Natural Science Foundation of China(No.81100401 and No.81470063)Guangdong Natural Science Foundation of China(No.2014A030313129)the Doctoral Fund of the Ministry of Education of China(No.20110171120096)
文摘Long-term gonadotropin-releasing hormone agonist（Gn RHa） administration before in vitro fertilization（IVF）/intracytoplasmic sperm injection（ICSI） in infertile women with endometriosis or adenomyosis significantly enhanced the chances of pregnancy in both fresh and frozen embryo transfer cycles. We hypothesized that long-term Gn RHa treatment might also be beneficial for the idiopathic repeated implantation failure（RIF） patients. In the 21 patients receiving Gn RHa and hormone replacement therapy（G-HRT） protocols for frozen embryo transfer, their data were compared with those of the 56 of frozen/fresh cycles they had previously undergone（previous protocols）. Comparison showed that the finial results were significantly better with G-HRT protocols than with their previous protocols, with pregnancy rate, clinical pregnancy rate, implantation rate and on-going pregnancy rate being 70%, 60%, 40% and 38% respectively with G-HRT protocols, against 17%, 11%, 6.3% and 5% with previous protocols. The results showed that hormonally controlled endometrial preparation with prior Gn RHa suppression could be used for patients who had experienced repeated failures of IVF treatment despite having morphologically optimal embryos, and the treatment may help increase the receptivity of the endometrium in these patients.
基金Funded by the National Natural Science Foundation of China(No.51278073)State Key Laboratoryfor GeoMechanics and Deep Underground Engineering,China University of Mining&Technology(No.SKLGDUEK1704)
文摘The feasibility of using different generations of recycled fine aggregate（RFA） in structural concrete in a chloride environment was evaluated by studying the performance of the RFA and the corresponding concrete. The different generations of RFA were recycled by following the cycle of ‘concrete-waste concrete-fine aggregate-concrete＇. The properties of three generations of repeatedly recycled fine aggregate（RRFA） were systematically investigated, and we focused on the compressive strength and splitting tensile strength and chloride ion permeability of the related structural concretes with 25%, 75%, and 100% replacement of natural fine aggregates with RFA. The results indicated that the quality of RRFA presents a trend of slow deterioration, but the overall performance of all RRFA still fulfils the quality requirements of recycled fine aggregate for structural concrete. All RRFA concretes achieved the target compressive strength of 40 MPa after 28 days except for the second generation of the recycled aggregate concrete and the third generation of the recycled aggregate concrete with 100% replacement, and all the concrete mixes achieved the target compressive strength after 90 days. The insights obtained in this study demonstrate the feasibility of using at least three generations of RRFA for the production of normal structural concrete with a design service life of 100 years in a chloride environment.
基金supported by National Basic Research Development Program of China (973 Program, 2013CB945603)the National Natural Science Foundation of China (31070944, 31271147, 31471063, 31671074)+1 种基金the Natural Science Foundation of Zhejiang Province (LR13C090001)the Fundamental Research Funds for the Central Universities, China (No. 2017FZA7003)
文摘Animals always seek rewards and the related neural basis has been well studied. However, what happens when animals fail to get a reward is largely unknown,although this is commonly seen in behaviors such as predation. Here, we set up a behavioral model of repeated failure in reward pursuit(RFRP) in Drosophila larvae. In this model, the larvae were repeatedly prevented from reaching attractants such as yeast and butyl acetate, before finally abandoning further attempts. After giving up, they usually showed a decreased locomotor speed and impaired performance in light avoidance and sugar preference,which were named as phenotypes of RFRP states. In larvae that had developed RFRP phenotypes, the octopamine concentration was greatly elevated, while tbh mutants devoid of octopamine were less likely to develop RFRP phenotypes, and octopamine feeding efficiently restored such defects. By down-regulating tbh in different groups of neurons and imaging neuronal activity, neurons that regulated the development of RFRP states and the behavioral exhibition of RFRP phenotypes were mapped to a small subgroup of non-glutamatergic and glutamatergic octopaminergic neurons in the central larval brain. Our results establish a model for investigating the effect of depriving an expected reward in Drosophila and provide a simplified framework for the associated neural basis.
基金supported by the National Natural Science Foundation of China (No. 51174191)the Ministry of Education Innovation Team (No. IRT0865)project supported by the National Science and Technology Ministry (No. 2012BAC10B03)
文摘DInSAR technology was used to monitor subsidence caused by underground coal mining activities in mountainous area, with multi source SAR data, including 8 EnviSAT C-band and 4 ALOS L-band, and 4 programmed TerraSAR-X dataset. The results revealed that 2-pass DInSAR technique sometimes failed to retrieve the mining-caused subsidence due to spatial and/or temporal de-correlation. We also noticed that there existed residual topographic phase after the compensation with SRTM DEM, which could almost overwhelm the subsidence information when the perpendicular baseline was relatively large. Based on the mining materials, analysis was made on the shape of subsidence area. For the well geocoded results from TerraSAR-X, confirmed by GPS surveying results of corner reflectors, we tried to extract the advance distance of influence besides the subsidence area. Due to the big deformation gradient over stopingfaces, the X-band SAR data could not capture the maximum value subsidence revealed by GPS survey in our preliminary results, the same as C-band EnviSAT data. This will turn to be our research subject in the next few months.
基金The project supported by the National Natural Science Foundation of China
文摘A family of modal methods for computing eigenvector derivatives with repeated roots are directly derived from the constraint generalized inverse technique which is originally formulated by Wang and Hu. Extensions are made to Akgun's method to allow treatment of eigensensitivity with repeated roots for general nondefective systems, and Bernard and Bronowicki's modal expansion approach is expanded to a family of modal methods.
