Structure of porous media and fluid distribution in rocks can significantly affect the transport characteristics during the process of microscale tracer flow.To clarify the effect of micro heterogeneity on aqueous tra...Structure of porous media and fluid distribution in rocks can significantly affect the transport characteristics during the process of microscale tracer flow.To clarify the effect of micro heterogeneity on aqueous tracer transport,this paper demonstrates microscopic experiments at pore level and proposes an improved mathematical model for tracer transport.The visualization results show a faster tracer movement into movable water than it into bound water,and quicker occupancy in flowing pores than in storage pores caused by the difference of tracer velocity.Moreover,the proposed mathematical model includes the effects of bound water and flowing porosity by applying interstitial flow velocity expression.The new model also distinguishes flowing and storage pores,accounting for different tracer transport mechanisms(dispersion,diffusion and adsorption)in different types of pores.The resulting analytical solution better matches with tracer production data than the standard model.The residual sum of squares(RSS)from the new model is 0.0005,which is 100 times smaller than the RSS from the standard model.The sensitivity analysis indicates that the dispersion coefficient and flowing porosity shows a negative correlation with the tracer breakthrough time and the increasing slope,whereas the superficial velocity and bound water saturation show a positive correlation.展开更多
The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA d...The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA data. The reaction products exhibit 12 compounds namely, Ba(NO3)2, αFe2O3, Fe3O4, BaFeO3, BaFeO2.9, hexagonal BaFeO3-x, tetragonal BaFeO3-x, BaFe2O4, αBaFe2O4, Ba2Fe6O11, Ba5Fe14O26 and BaFe12O19. The formation of these products depend on the molar ratio between the reactants and the reaction temperature. The reaction products were studied by DTA and TG techniques and characterized by X-ray diffraction patterns, magnetic susceptibility data and scanning electron microscopy, SEM.展开更多
Objective To explore the invasion of different types of meningeoma to their surrounding tissue. Methods The specimen from 124 patients with meningeomas,who underwent surgery in Southern Hospital from April 2009 to Jun...Objective To explore the invasion of different types of meningeoma to their surrounding tissue. Methods The specimen from 124 patients with meningeomas,who underwent surgery in Southern Hospital from April 2009 to June 2010 were used to analyze the invasion of different types of meningeomas to their surrounding tissue. All the tumors were resected in the standard of Simposon I. We referred to WHO 2007展开更多
Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a m...Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a major threat to global ecological stability. Variations in stability among different ecosystemshave been confirmed, but it remains unclear whether there are differences in stability within the sameterrestrial vegetation ecosystem under the influence of climate events in different directions and intensities.China's grassland ecosystem includes most grassland types and is a good choice for studying this issue.This study used the Standardized Precipitation Evapotranspiration Index-12 (SPEI-12) to identify thedirections and intensities of different types of climate events, and based on Normalized DifferenceVegetation Index (NDVI), calculated the resistance and resilience of different grassland types for 30consecutive years from 1990 to 2019 (resistance and resilience are important indicators to measurestability). Based on a traditional regression model, standardized methods were integrated to analyze theimpacts of the intensity and duration of drought and wet events on vegetation stability. The resultsshowed that meadow steppe exhibited the highest stability, while alpine steppe and desert steppe had thelowest overall stability. The stability of typical steppe, alpine meadow, temperate meadow was at anintermediate level. Regarding the impact of the duration and intensity of climate events on vegetationecosystem stability for the same grassland type, the resilience of desert steppe during drought was mainlyaffected by the duration. In contrast, the impact of intensity was not significant. However, alpine steppewas mainly affected by intensity in wet environments, and duration had no significant impact. Ourconclusions can provide decision support for the future grassland ecosystem governance.展开更多
Upland red soil has strong acidity and low fertility, different woodland types produce varying impacts on soil properties and nematode communities. To explore the response of soil, 2 different types of woodland were s...Upland red soil has strong acidity and low fertility, different woodland types produce varying impacts on soil properties and nematode communities. To explore the response of soil, 2 different types of woodland were selected to investigate the changes of soil properties and nematode communities compared to wasteland. The results showed that the content of soil organic carbon and total nitrogen in chestnut forest soil were the highest, 16.41 g/kg and 0.46 g/kg respectively; while the highest contents of soil microbial biomass carbon, nitrogen and phosphorus appeared in wasteland soil, and basal respiration of wasteland soil was 28.36 mg CO_2/kg·d, significantly higher than that of the other 2 soils(p <0.05). The nematode abundance also reached the peak in wasteland soil. Three types of soil exhibited a completely different nematode community structure: the dominant trophic group in wasteland soil was herbivores,while omnivores/predators and bacterivores in forest from farmland and chestnut forest soil, respectively.The influence of different types of woodland on ecological indices of nematode communities was not consistent. Degradation trends of soil properties and nematode communities were presented in the 2woodland types compared with wasteland soil. These results are instructive for the local woodland planning.展开更多
By differentiating four different types of output, the paperargues that their roles are also different. And learners of differ-ent language proficiency levels should be guided to produce dif-ferent types of output. Th...By differentiating four different types of output, the paperargues that their roles are also different. And learners of differ-ent language proficiency levels should be guided to produce dif-ferent types of output. Thus the paper introduces a new concept,namely "optimal output". Blindly making the learner produceoutput which is far beyond his current English level will only doharm to his interlanguage development, making it fossilize at anearly stage.展开更多
The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low...The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low-speed model test. However, this method is problematic for ships with bulbous bows and transom. In this article, a Computational Fluid Dynamics(CFD)-based method is introduced to obtain k for different type of ships at different drafts, and a comparison is made between the CFD method and the model test. The results show that the CFD method produces reasonable k values. A grid generating method and turbulence model are briefly discussed in the context of obtaining a consistent k using CFD.展开更多
Accurate estimate of soil carbon storage is essential to reveal the role of soil in global carbon cycle. However, there is large uncertainty on the estimation of soil organic carbon(SOC) storage in grassland among pre...Accurate estimate of soil carbon storage is essential to reveal the role of soil in global carbon cycle. However, there is large uncertainty on the estimation of soil organic carbon(SOC) storage in grassland among previous studies, and the study on soil inorganic carbon(SIC) is still lack. We surveyed 153 sites during plant peak growing season and estimated SOC and SIC for temperate desert, temperate steppe, alpine steppe, steppe meadow, alpine meadow and swamp, which covered main grassland in the Qinghai Plateau during 2011 to 2012. The results showed that the vertical and spatial distributions of SOC and SIC varied by grassland types. The SOC amount mainly decreased from southeast to northwest, whereas the SIC amount increased from southeast to northwest. The magnitude of SOC amount in the top 50 cm across grassland types ranked by: swamp > alpine meadow >steppe meadow > temperate steppe > alpine steppe > temperate desert, while the SIC amount showed an opposite order. There was a great deal of variation in proportion of SOC and SIC among different grassland types(from 55.17 to 94.59 for SOC and 5.14 to 44.83 for SIC). The total SOC and SIC storage was 5.78 Pg and 1.37 Pg, respectively, in the top 50 cm of soil in Qinghai Province. The mixed linear model revealed that grassland types was the predominant factor in spatial variations of SOC amount while grassland types and soil p H accounted for those of SIC amount. Our results suggested that the community shift of alpine meadow towards alpine grassland induced by climate warming would decrease carbon sequestration capacity by 6.0 kg C m2.展开更多
Uemura [1] discovered the mapping formula for Type 1 Vague events and presented an alternative problem as an example of its application. Since it is well known that the alternative problem leads to sequential Bayesian...Uemura [1] discovered the mapping formula for Type 1 Vague events and presented an alternative problem as an example of its application. Since it is well known that the alternative problem leads to sequential Bayesian inference, the flow of subsequent research was to make the mapping formula multidimensional, to introduce the concept of time, and to derive a Markov (decision) process. Furthermore, we formulated stochastic differential equations to derive them [2]. This paper refers to type 2 vague events based on a second-order mapping equation. This quadratic mapping formula gives a certain rotation named as possibility principal factor rotation by transforming a non-mapping function by a relation between two mapping functions. In addition, the derivation of the Type 2 Complex Markov process and the initial and stopping conditions in this rotation are mentioned. .展开更多
BACKGROUND In clinical work,85%-90%of malignant thyroid diseases are papillary thyroid cancer(PTC);thus,clinicians neglect other types of thyroid cancer,such as medullary thyroid carcinoma(MTC).CASE SUMMARY We report ...BACKGROUND In clinical work,85%-90%of malignant thyroid diseases are papillary thyroid cancer(PTC);thus,clinicians neglect other types of thyroid cancer,such as medullary thyroid carcinoma(MTC).CASE SUMMARY We report a 53-year-old female patient with a preoperative calcitonin level of 345 pg/mL.There was no definitive diagnosis of MTC by preoperative fine-needle aspiration cytology or intraoperative frozen pathology,but the presence of PTC and MTC was confirmed by postoperative paraffin pathology.The patient underwent total thyroidectomy and bilateral central lymph node dissection.Close follow-up at 1.5 years after surgery revealed no signs of recurrence or metastasis.CONCLUSION The issue in clinical work-up regarding types of thyroid cancer provides a novel and challenging idea for the surgical treatment of MTC.In the absence of central lymph node metastasis,it is worth addressing whether patients with high calcitonin can undergo total thyroidectomy and bilateral central lymph node dissection without bilateral lateral neck lymph node dissection.展开更多
As is well known,the definitions of fractional sum and fractional difference of f(z)on non-uniform lattices x(z)=c1z^(2)+c2z+c3 or x(z)=c1q^(z)+c2q^(-z)+c3 are more difficult and complicated.In this article,for the fi...As is well known,the definitions of fractional sum and fractional difference of f(z)on non-uniform lattices x(z)=c1z^(2)+c2z+c3 or x(z)=c1q^(z)+c2q^(-z)+c3 are more difficult and complicated.In this article,for the first time we propose the definitions of the fractional sum and fractional difference on non-uniform lattices by two different ways.The analogue of Euler’s Beta formula,Cauchy’Beta formula on non-uniform lattices are established,and some fundamental theorems of fractional calculas,the solution of the generalized Abel equation on non-uniform lattices are obtained etc.展开更多
Objective To evaluate the effects of Acarbose on incretin level(glucagon-like peptide 1(GLP-1)and gastric inhibitory polypeptide(GIP)of type 2 diabetes mellitus(T2DM)patients after different kinds of glucose load.Meth...Objective To evaluate the effects of Acarbose on incretin level(glucagon-like peptide 1(GLP-1)and gastric inhibitory polypeptide(GIP)of type 2 diabetes mellitus(T2DM)patients after different kinds of glucose load.Methods A total of 32 newly diagnosed T2DM patients were enrolled in this study and randomly divided into展开更多
The Photovoltaic/thermal(PV/T)system combines the conventional PV panel with solar collector into one integrated system,which could achieve the function of generating power and providing thermal energy at the same tim...The Photovoltaic/thermal(PV/T)system combines the conventional PV panel with solar collector into one integrated system,which could achieve the function of generating power and providing thermal energy at the same time.Recently,it has become the most promising solar system for building applications.Most of the PV/T systems use water as the coolant,which could cause freezing problem in winter.To overcome this problem,the heat pipe PV/T system is developed to provide electrical and thermal energy stably without the seasonal barrier.Although some published review works have involved this type of PV/T system,they just stated a simple introduction on it,acting as a small part of their works.This paper focuses on the heat pipe PV/T system independently and provides a comprehensive and in-depth analysis of its performance.Firstly,the structure and operational principles of the heat pipe PV/T module and system are introduced concisely.Then the features and performance of different types of heat pipe PV/T systems,i.e.,integral heat pipe,loop heat pipe,and pulsating heat pipe PV/T system,are presented and analyzed.This is followed by the review on the performance of the systems which combine heat pipe PV/T module and other devices.Finally,the research gaps in this field are identified,and some future research trends and directions are recommended.展开更多
基金funded by National Science and Technology Major Projects(2017ZX05009004,2016ZX05058003)Beijing Natural Science Foundation(2173061)and State Energy Center for Shale Oil Research and Development(G5800-16-ZS-KFNY005).
文摘Structure of porous media and fluid distribution in rocks can significantly affect the transport characteristics during the process of microscale tracer flow.To clarify the effect of micro heterogeneity on aqueous tracer transport,this paper demonstrates microscopic experiments at pore level and proposes an improved mathematical model for tracer transport.The visualization results show a faster tracer movement into movable water than it into bound water,and quicker occupancy in flowing pores than in storage pores caused by the difference of tracer velocity.Moreover,the proposed mathematical model includes the effects of bound water and flowing porosity by applying interstitial flow velocity expression.The new model also distinguishes flowing and storage pores,accounting for different tracer transport mechanisms(dispersion,diffusion and adsorption)in different types of pores.The resulting analytical solution better matches with tracer production data than the standard model.The residual sum of squares(RSS)from the new model is 0.0005,which is 100 times smaller than the RSS from the standard model.The sensitivity analysis indicates that the dispersion coefficient and flowing porosity shows a negative correlation with the tracer breakthrough time and the increasing slope,whereas the superficial velocity and bound water saturation show a positive correlation.
文摘The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA data. The reaction products exhibit 12 compounds namely, Ba(NO3)2, αFe2O3, Fe3O4, BaFeO3, BaFeO2.9, hexagonal BaFeO3-x, tetragonal BaFeO3-x, BaFe2O4, αBaFe2O4, Ba2Fe6O11, Ba5Fe14O26 and BaFe12O19. The formation of these products depend on the molar ratio between the reactants and the reaction temperature. The reaction products were studied by DTA and TG techniques and characterized by X-ray diffraction patterns, magnetic susceptibility data and scanning electron microscopy, SEM.
文摘Objective To explore the invasion of different types of meningeoma to their surrounding tissue. Methods The specimen from 124 patients with meningeomas,who underwent surgery in Southern Hospital from April 2009 to June 2010 were used to analyze the invasion of different types of meningeomas to their surrounding tissue. All the tumors were resected in the standard of Simposon I. We referred to WHO 2007
基金the National Natural Science Foundation of China(42271289).
文摘Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a major threat to global ecological stability. Variations in stability among different ecosystemshave been confirmed, but it remains unclear whether there are differences in stability within the sameterrestrial vegetation ecosystem under the influence of climate events in different directions and intensities.China's grassland ecosystem includes most grassland types and is a good choice for studying this issue.This study used the Standardized Precipitation Evapotranspiration Index-12 (SPEI-12) to identify thedirections and intensities of different types of climate events, and based on Normalized DifferenceVegetation Index (NDVI), calculated the resistance and resilience of different grassland types for 30consecutive years from 1990 to 2019 (resistance and resilience are important indicators to measurestability). Based on a traditional regression model, standardized methods were integrated to analyze theimpacts of the intensity and duration of drought and wet events on vegetation stability. The resultsshowed that meadow steppe exhibited the highest stability, while alpine steppe and desert steppe had thelowest overall stability. The stability of typical steppe, alpine meadow, temperate meadow was at anintermediate level. Regarding the impact of the duration and intensity of climate events on vegetationecosystem stability for the same grassland type, the resilience of desert steppe during drought was mainlyaffected by the duration. In contrast, the impact of intensity was not significant. However, alpine steppewas mainly affected by intensity in wet environments, and duration had no significant impact. Ourconclusions can provide decision support for the future grassland ecosystem governance.
基金Sponsored by National Youth Natural Science Foundation of China(41301235)
文摘Upland red soil has strong acidity and low fertility, different woodland types produce varying impacts on soil properties and nematode communities. To explore the response of soil, 2 different types of woodland were selected to investigate the changes of soil properties and nematode communities compared to wasteland. The results showed that the content of soil organic carbon and total nitrogen in chestnut forest soil were the highest, 16.41 g/kg and 0.46 g/kg respectively; while the highest contents of soil microbial biomass carbon, nitrogen and phosphorus appeared in wasteland soil, and basal respiration of wasteland soil was 28.36 mg CO_2/kg·d, significantly higher than that of the other 2 soils(p <0.05). The nematode abundance also reached the peak in wasteland soil. Three types of soil exhibited a completely different nematode community structure: the dominant trophic group in wasteland soil was herbivores,while omnivores/predators and bacterivores in forest from farmland and chestnut forest soil, respectively.The influence of different types of woodland on ecological indices of nematode communities was not consistent. Degradation trends of soil properties and nematode communities were presented in the 2woodland types compared with wasteland soil. These results are instructive for the local woodland planning.
文摘By differentiating four different types of output, the paperargues that their roles are also different. And learners of differ-ent language proficiency levels should be guided to produce dif-ferent types of output. Thus the paper introduces a new concept,namely "optimal output". Blindly making the learner produceoutput which is far beyond his current English level will only doharm to his interlanguage development, making it fossilize at anearly stage.
基金Supported by Ministry of Industry and Information(No.K24097)
文摘The value of form factor k at different drafts is important in predicting full-scale total resistance and speed for different types of ships. In the ITTC community, most organizations predict form factor k using a low-speed model test. However, this method is problematic for ships with bulbous bows and transom. In this article, a Computational Fluid Dynamics(CFD)-based method is introduced to obtain k for different type of ships at different drafts, and a comparison is made between the CFD method and the model test. The results show that the CFD method produces reasonable k values. A grid generating method and turbulence model are briefly discussed in the context of obtaining a consistent k using CFD.
基金supported by the“Natural Science Foundation of China(41030105)"“Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues”of the Chinese Academy of Sciences(XDA05050404)
文摘Accurate estimate of soil carbon storage is essential to reveal the role of soil in global carbon cycle. However, there is large uncertainty on the estimation of soil organic carbon(SOC) storage in grassland among previous studies, and the study on soil inorganic carbon(SIC) is still lack. We surveyed 153 sites during plant peak growing season and estimated SOC and SIC for temperate desert, temperate steppe, alpine steppe, steppe meadow, alpine meadow and swamp, which covered main grassland in the Qinghai Plateau during 2011 to 2012. The results showed that the vertical and spatial distributions of SOC and SIC varied by grassland types. The SOC amount mainly decreased from southeast to northwest, whereas the SIC amount increased from southeast to northwest. The magnitude of SOC amount in the top 50 cm across grassland types ranked by: swamp > alpine meadow >steppe meadow > temperate steppe > alpine steppe > temperate desert, while the SIC amount showed an opposite order. There was a great deal of variation in proportion of SOC and SIC among different grassland types(from 55.17 to 94.59 for SOC and 5.14 to 44.83 for SIC). The total SOC and SIC storage was 5.78 Pg and 1.37 Pg, respectively, in the top 50 cm of soil in Qinghai Province. The mixed linear model revealed that grassland types was the predominant factor in spatial variations of SOC amount while grassland types and soil p H accounted for those of SIC amount. Our results suggested that the community shift of alpine meadow towards alpine grassland induced by climate warming would decrease carbon sequestration capacity by 6.0 kg C m2.
文摘Uemura [1] discovered the mapping formula for Type 1 Vague events and presented an alternative problem as an example of its application. Since it is well known that the alternative problem leads to sequential Bayesian inference, the flow of subsequent research was to make the mapping formula multidimensional, to introduce the concept of time, and to derive a Markov (decision) process. Furthermore, we formulated stochastic differential equations to derive them [2]. This paper refers to type 2 vague events based on a second-order mapping equation. This quadratic mapping formula gives a certain rotation named as possibility principal factor rotation by transforming a non-mapping function by a relation between two mapping functions. In addition, the derivation of the Type 2 Complex Markov process and the initial and stopping conditions in this rotation are mentioned. .
基金Supported by National Natural Science Foundation of China,No.81860469Zunyi Science and Technology Bureau,China,ZunShi KeHe HZ(2019)No.85Honghuagang District Science and Technology Bureau of Zunyi City,China,ZunHong KeHe Shezi(2018)No.12.
文摘BACKGROUND In clinical work,85%-90%of malignant thyroid diseases are papillary thyroid cancer(PTC);thus,clinicians neglect other types of thyroid cancer,such as medullary thyroid carcinoma(MTC).CASE SUMMARY We report a 53-year-old female patient with a preoperative calcitonin level of 345 pg/mL.There was no definitive diagnosis of MTC by preoperative fine-needle aspiration cytology or intraoperative frozen pathology,but the presence of PTC and MTC was confirmed by postoperative paraffin pathology.The patient underwent total thyroidectomy and bilateral central lymph node dissection.Close follow-up at 1.5 years after surgery revealed no signs of recurrence or metastasis.CONCLUSION The issue in clinical work-up regarding types of thyroid cancer provides a novel and challenging idea for the surgical treatment of MTC.In the absence of central lymph node metastasis,it is worth addressing whether patients with high calcitonin can undergo total thyroidectomy and bilateral central lymph node dissection without bilateral lateral neck lymph node dissection.
基金Supported by the National Natural Science Foundation Fujian province of China(2016J01032).
文摘As is well known,the definitions of fractional sum and fractional difference of f(z)on non-uniform lattices x(z)=c1z^(2)+c2z+c3 or x(z)=c1q^(z)+c2q^(-z)+c3 are more difficult and complicated.In this article,for the first time we propose the definitions of the fractional sum and fractional difference on non-uniform lattices by two different ways.The analogue of Euler’s Beta formula,Cauchy’Beta formula on non-uniform lattices are established,and some fundamental theorems of fractional calculas,the solution of the generalized Abel equation on non-uniform lattices are obtained etc.
文摘Objective To evaluate the effects of Acarbose on incretin level(glucagon-like peptide 1(GLP-1)and gastric inhibitory polypeptide(GIP)of type 2 diabetes mellitus(T2DM)patients after different kinds of glucose load.Methods A total of 32 newly diagnosed T2DM patients were enrolled in this study and randomly divided into
基金The work of this paper is sponsored by Sichuan Science and Technology Support Program(19ZDYF1865)Sichuan Science and Technology Program(Project No.2020JDRC0036)+1 种基金Chengdu Science and Technology Project(Project No.2019-YF05-01326-SN)Fundamental Research Funds for the Central Universities(Project No.2682020CX36).
文摘The Photovoltaic/thermal(PV/T)system combines the conventional PV panel with solar collector into one integrated system,which could achieve the function of generating power and providing thermal energy at the same time.Recently,it has become the most promising solar system for building applications.Most of the PV/T systems use water as the coolant,which could cause freezing problem in winter.To overcome this problem,the heat pipe PV/T system is developed to provide electrical and thermal energy stably without the seasonal barrier.Although some published review works have involved this type of PV/T system,they just stated a simple introduction on it,acting as a small part of their works.This paper focuses on the heat pipe PV/T system independently and provides a comprehensive and in-depth analysis of its performance.Firstly,the structure and operational principles of the heat pipe PV/T module and system are introduced concisely.Then the features and performance of different types of heat pipe PV/T systems,i.e.,integral heat pipe,loop heat pipe,and pulsating heat pipe PV/T system,are presented and analyzed.This is followed by the review on the performance of the systems which combine heat pipe PV/T module and other devices.Finally,the research gaps in this field are identified,and some future research trends and directions are recommended.