To explore whether condom use is influenced by power relation in commercial sex behaviors. Methods Variables were designed to measure the power relation in commercial sex behaviors based on the theory of gender and po...To explore whether condom use is influenced by power relation in commercial sex behaviors. Methods Variables were designed to measure the power relation in commercial sex behaviors based on the theory of gender and power relation and data were collected from male sexually transmitted diseases （STD） patients and female commercial sex workers （FSWs） working at recreation centers or being detained in a women education center to identify the relationship between condom use and power relation in male and female respondents using bivariate and multiple regression analysis. Results A significant relationship was identified between power relation and female condom use, the higher the score of power relations, the higher frequency the condom use, but no similar result was found in males. Females got a higher score of power relation than males. Conclusions Power relation is one of the factors that influence condom use, which should be considered when relevant theories are used to study the rate of condom use. It is worthwhile exploring the relationship between safe sex and power relation in spouses and regular sex partners when interventions are adopted to prevent HIV/AIDS spreading from high risk groups to the general population.展开更多
Wang: Speaking of Sino-U. S. relations, actually it touches upon great power relationship. The current Iraqi crisis became a focus in UN. There is a clear demarcation line between those countries supporting a war and ...Wang: Speaking of Sino-U. S. relations, actually it touches upon great power relationship. The current Iraqi crisis became a focus in UN. There is a clear demarcation line between those countries supporting a war and those countries in favor of weapons inspections within展开更多
This study explored the construction of power relations in the cognitive assessment of older adults within the Chinese clinical context.Data is derived from audio and video recordings that nine older adults produced i...This study explored the construction of power relations in the cognitive assessment of older adults within the Chinese clinical context.Data is derived from audio and video recordings that nine older adults produced in the cognitive assessment of the Chinese version of the Montreal Cognitive Assessment-Basic(MoCA-B),which were then annotated and analyzed from a multimodal pragmatic perspective.The study reveals that examiners and older adults employed various speech acts to achieve distinct communicative goals,with power relations between them being reflected through these speech acts.Examiners tend to claim high power,utilizing discourse strategies such as request,interruption,evaluation,rhetorical questions,and directive speech acts.In contrast,older adults assert high power through directive speech acts,rhetorical questions,and interruptions.Both parties also exhibit low power by using confirming questions and explanations.Additionally,gestures,smiles,prosody features,and other non-verbal communicative resources are synergistically employed to exercise power.The interactive mechanism of constructing power relations reveals that age affects older adults’power relations construction even in a professional setting of the Chinese context.The negotiation between the advanced age of older adults and the expertise of examiners jointly shapes power relations in their interactions.展开更多
The year of 2016 witnessed the balance of internal and external situations, calm and steady actions and proper planning in major power diplomacy with Chinese characteristics. Those were reflected in the success of the...The year of 2016 witnessed the balance of internal and external situations, calm and steady actions and proper planning in major power diplomacy with Chinese characteristics. Those were reflected in the success of the G20 summit, the vigorous promotion of the"One Belt, One Road"(B&R) Initiative and the active promotion of international cooperation on development, which acquired positive response and general agreement from the international community and made special contributions to building a more just and reasonable international order.Those were also reflected in the active management of major power relations and sound responses to the changing situation in the surrounding area to create good external environment for domestic development. In addition, further expansion and defending of overseas interests set higher standards for Chinese diplomacy. Having been pushed by the era to the forefront, China is performing its responsibility as a major power in a peculiar way and will certainly make greater contributions to world peace and development.展开更多
To cope with the current crisis and tensions full-filled China-US relationship, Chinese President Xi Jinping put forward the concept of building a new model of China-US big power relations, which the US agrees. Yet th...To cope with the current crisis and tensions full-filled China-US relationship, Chinese President Xi Jinping put forward the concept of building a new model of China-US big power relations, which the US agrees. Yet the new model won a heated discussion. In China this new model was evaluated positively and optimistically, while in the US it was perceived as a strategic challenge or even a threat. In the present article, the author proposes that this new model of China-US big power relations is more like a symbolic sign in foreign affairs rather than a strategic challenge or a threat or an effective and workable mechanism at this moment, and meanwhile analyses this view from diachronic and semiotic perspectives. The analyses reveal that the new model functions as a symbolic sign, signifying to the world that conceptually the two big powers have a good and harmonious relationship.展开更多
Over the past two years, India's Modi government has demonstrated the following features: focusing on the goals of becoming a great power and shaping India's South Asian dominance, expanding the scope of diplo...Over the past two years, India's Modi government has demonstrated the following features: focusing on the goals of becoming a great power and shaping India's South Asian dominance, expanding the scope of diplomatic strategy, emphasizing the role of soft power and focusing on self-development as well as external environment. Modi's great power strategy is deeply influenced by the Indian realistic international political outlook and, to a certain extent, reflects the governing philosophy of the Bharatiya Janata Party. The great power strategy is Modi's governing foundation and governing style, embedding Modi distinctive personal style. Under the influence of the great power strategy, China and India have increased their economic cooperation scope, widening the forms of public diplomacy, with an obvious geopolitical collision; India is taking more measures to check China.展开更多
As a noted modern American playwright, David Mamet attracts wide attention from the readers, the audience, as well as the academic circle with his fascinating language features. In his plays, in order to achieve their...As a noted modern American playwright, David Mamet attracts wide attention from the readers, the audience, as well as the academic circle with his fascinating language features. In his plays, in order to achieve their individual goals, the male characters, applying the discursive power with language as weapon, endeavor to build a new structure of power. It aims to analyze A Life in the Theatre, with such discourse-analysis mechanics as turn-taking and politeness strategy, to examine the power relations between the two male characters in the play, and finally to explain how discourse influence and alter the power relations in reality.展开更多
The impeller configuration with a six parabolic blade disk turbine below two down-pumping hydrofoil propellers, identified as PDT + 2CBY, was used in this study. The effect of the impeller diameter D, ranging from0.30...The impeller configuration with a six parabolic blade disk turbine below two down-pumping hydrofoil propellers, identified as PDT + 2CBY, was used in this study. The effect of the impeller diameter D, ranging from0.30 T to 0.40T(T as the tank diameter), on gas dispersion in a stirred tank of 0.48 m diameter was investigated by experimental and CFD simulation methods. Power consumption and total gas holdup were measured for the same impeller configuration PDT + 2CBY with four different D/T. Results show that with D/T increases from 0.30 to 0.40, the relative power demand(RPD) in a gas–liquid system decreases slightly. At low superficial gas velocity VSof 0.0078 m·s-1, the gas holdup increases evidently with the increase of D/T. However, at high superficial gas velocity, the system with D/T = 0.33 gets a good balance between the gas recirculation and liquid shearing rate, which resulted in the highest gas holdup among four different D/T. CFD simulation based on the two-fluid model along with the Population Balance Model(PBM) was used to investigate the effect of impeller diameter on the gas dispersion. The power consumption and total gas holdup predicted by CFD simulation were in reasonable agreement with the experimental data.展开更多
Magnetic properties and structures in La1-zPrz(Fe0.895–xCoxSi0.105)13 (x=0.07, 0.08; z=0, 0.2, 0.4) compounds were investigated. When Pr and Co substituted for La and Fe, the Curie temperature of the compounds was ad...Magnetic properties and structures in La1-zPrz(Fe0.895–xCoxSi0.105)13 (x=0.07, 0.08; z=0, 0.2, 0.4) compounds were investigated. When Pr and Co substituted for La and Fe, the Curie temperature of the compounds was adjusted to around room temperature. The magnetic phase transition was driven from first-order to second-order due to Co substitution. As a second-order phase transition material, the MCE of La0.6Pr0.4(Fe0.825Co0.07Si0.105)13, whose relative cooling power was 175 J/kg under a field change of 2 T, ...展开更多
To investigate whether and how manual acupuncture（MA） modulates brain activities,we design an experiment where acupuncture at acupoint ST36 of the right leg is used to obtain electroencephalograph（EEG） signals in ...To investigate whether and how manual acupuncture（MA） modulates brain activities,we design an experiment where acupuncture at acupoint ST36 of the right leg is used to obtain electroencephalograph（EEG） signals in healthy subjects.We adopt the autoregressive（AR） Burg method to estimate the power spectrum of EEG signals and analyze the relative powers in delta（0 Hz-4 Hz）,theta（4 Hz-8 Hz）,alpha（8 Hz-13 Hz）,and beta（13 Hz-30 Hz） bands.Our results show that MA at ST36 can significantly increase the EEG slow wave relative power（delta band） and reduce the fast wave relative powers（alpha and beta bands）,while there are no statistical differences in theta band relative power between different acupuncture states.In order to quantify the ratio of slow to fast wave EEG activity,we compute the power ratio index.It is found that the MA can significantly increase the power ratio index,especially in frontal and central lobes.All the results highlight the modulation of brain activities with MA and may provide potential help for the clinical use of acupuncture.The proposed quantitative method of acupuncture signals may be further used to make MA more standardized.展开更多
The lattice parameter and magnetocaloric properties of three samples of LaFe11.2Co0.7Si1.1-xGax with x = 0, 0.03 and 0.05 have been investigated by X-ray powder diffraction and magnetization measurements. The lattice ...The lattice parameter and magnetocaloric properties of three samples of LaFe11.2Co0.7Si1.1-xGax with x = 0, 0.03 and 0.05 have been investigated by X-ray powder diffraction and magnetization measurements. The lattice parameter increases slightly and the Curie temperature increases somewhat with increasing gallium content. However, a small amount of Ga doping into the sample decreases the magnetic entropy change of the sample. All the samples remain in the first-order magnetic phase transition. The most striking effect of the Ga doping is that the cooling capacity in the samples increases significantly. The maximum magnetic entropy change, ASM and the cooling capacity of the sample LaFe11.2Co0.7Si1.07Ga0.03 are 11.9 J·kg^-1·K^-1 and 254.8 J·kg^-1, respectively.展开更多
We reported the magnetic properties and magnetocaloric effects(MCE) of(La0.8Ho0.2)2/3Ca1/3MnO3 and(La0.5Ho0.5)2/3Ca1/3MnO3 nanoparticles by sol-gel technique.With this method,we were able to obtain the samples with pa...We reported the magnetic properties and magnetocaloric effects(MCE) of(La0.8Ho0.2)2/3Ca1/3MnO3 and(La0.5Ho0.5)2/3Ca1/3MnO3 nanoparticles by sol-gel technique.With this method,we were able to obtain the samples with particle diameters ranging from 50 to 200 nm.In the(La1-xHox)2/3Ca1/3MnO3 compound,an external magnetic field induced a magnetic transition from an paramagnetic phase to a ferromagnetic phase above Ts=105-135 K,leading to magnetocaloric effects.The maximum value of ΔSM was 1.19 J/(kg·K) at 100 K and 2.03 J/(kg·K) at 152 K for a magnetic field change of 5 T.Because both samples had large relative cooling power(RCP) and wide δTFWHM,the study on systems with the(La1-xHox)2/3Ca1/3MnO3-related magnetic transitions may open an important field in searching good magnetic materials.展开更多
Co-seismic gas leakage usually occurs on the edge of seismic faults in petroliferous basins,and it may have an impact on the local environment,such as the greenhouse effect,which can cause thermal infrared brightness ...Co-seismic gas leakage usually occurs on the edge of seismic faults in petroliferous basins,and it may have an impact on the local environment,such as the greenhouse effect,which can cause thermal infrared brightness anomalies.Using wavelet transform and power spectrum estimation methods,we processed brightness temperature data from the Chinese geostationary meteorological satellite FY-C/E.We report similarities between the co-seismic thermal infrared brightness(CTIB)anomalies before,during and after earthquakes that occurred at the edges of the Sichuan,Tarim,Qaidam,and Junggar basins surrounding the North and East of the Qinghai–Tibet Plateau in western China.Additionally,in each petroliferous basin,the area of a single CTIB anomaly accounted for 50%to 100%of the basin area,and the spatial distribution similarities in the CTIB anomalies existed before,during and after these earthquakes.To better interpret the similarities,we developed a basin warming effect model based on geological structures and topography.The model suggests that in a petroliferous basin with a subsurface gas reservoir,gas leakage could strengthen with the increasing stress before,during,and even after an earthquake.The accumulation of these gases,such as the greenhouse gases CH4 and CO2,results in the CTIB anomalies.In addition,we conclude that the CTIB anomalies are strengthened by the high mountains(altitude^5000 m)around the basins and the basins’independent climatic conditions.This work provides a new perspective from which to understand the CTIB anomalies in petroliferous basins surrounding the North and East of the Qinghai–Tibet Plateau.展开更多
The effects of impeller type, stirring power, gas flow rate, and liquid concentration on the gas–liquid mixing in a shear-thinning system with a coaxial mixer were investigated by experiment, and the overall gas hold...The effects of impeller type, stirring power, gas flow rate, and liquid concentration on the gas–liquid mixing in a shear-thinning system with a coaxial mixer were investigated by experiment, and the overall gas holdup, relative power demand, and volumetric mass transfer coefficient under different conditions were compared. The results show that, the increasing stirring power or gas flow rate is beneficial in promoting the overall gas holdup and volumetric mass transfer coefficient, while the increasing system viscosity weakens the mass transfer in a shearing–thinning system. Among the three turbines, the six curved-blade disc turbine(BDT-6) exhibits the best gas pumping capacity; the six 45° pitched-blade disc turbine(PBDT-6) has the highest volumetric mass transfer coefficient at the same unit volume power.展开更多
A systematic investigation on the structural, magnetic and magnetocaloric properties of Pr_（0.6）Sr_（0.4-x）Ag_xMnO_3（x=0.05 and 0.1） manganites was reported. Rietveld refinements of the X-ray diffraction patterns...A systematic investigation on the structural, magnetic and magnetocaloric properties of Pr_（0.6）Sr_（0.4-x）Ag_xMnO_3（x=0.05 and 0.1） manganites was reported. Rietveld refinements of the X-ray diffraction patterns confirmed that all samples were single phase and crystallized in the orthorhombic structure with Pnma space group. Magnetic measurements in a magnetic applied field of 0.01T revealed that the ferromagnetic-paramagnetic transition temperature T_C decreased from about 293 to 290 K with increasing silver content from x=0.05 to 0.1. The reported magnetocaloric entropy change and relative cooling power for both samples were considerably remarkable with a △S_（max） value of 1.9 J/（kg·K）and maximum RCP values of 100 J/kg, under a magnetic field change（？μ0H） equal to 1.8T. The analysis of the universal curves gave an evidence of a second order magnetic transition for the studied samples. The magnetic field influence on both the magnetic entropy change and the relative cooling power was also studied and discussed.展开更多
The height of total entropy(S)for a magnetic refrigerant material is essentially concerned with the magnetic and structural transitions.However,the participation of such transitions in layered materials is not well un...The height of total entropy(S)for a magnetic refrigerant material is essentially concerned with the magnetic and structural transitions.However,the participation of such transitions in layered materials is not well understood.Therefore,the purpose of this work is to investigate the interplay between double layer lattice with their single perovskite counterpart,to achieve optimal magnetocaloric performance.A series of self-doped Pr_(1.4+x)Sr_(1.6-x)Mn_(2)O_(7)(0.0≤x≤0.5)Ruddlesden-Popper(R-P)perovskite have been prepared through the solid-state sintering method.With increasing the Pr-stoichiometry,the lattice faults have increased and the double layer lattice dramatically disintegrates into single perovskite structure.Due to the reduction of bilayer R-P phase into single perovskite the spin crossover occurs from weak bilayer(T=304 K)interactions towards the strong three-dimensional(T=308 K)interactions respectively.This series consistently develops thermomagnetic irreversibility in zero-field cooled(ZFC)-field cooled(FC)magnetization,which is indicative of a spin-glass state.The glassy nature has been ascribed collectively to the lattice strain produced because of dislocations and to an antiferromagnetic phase segregated at the surface.The maximum value of temperature average entropy change(TEC)and adiabatic temperature(ΔT)has enhanced nearly by 4 folds from 0.53 J kg^(-1)K^(-1),0.59 K(for x=0.0)up to 1.85 J kg^(-1)K^(-1),10 K(for x=0.5)at 2.5 T,respectively.Additionally,the room temperature relative cooling power has improved from 26.94 J/kg up to 77.84 J/kg with an applied field of 2.5 T.Our findings in this work suggest that the controlled reduction of double layer lattice into single perovskite and/or existence of both phases simultaneously in bilayer R-P manganites may be very effective in obtaining the desirable characteristics of magnetocaloric effects.展开更多
文摘To explore whether condom use is influenced by power relation in commercial sex behaviors. Methods Variables were designed to measure the power relation in commercial sex behaviors based on the theory of gender and power relation and data were collected from male sexually transmitted diseases （STD） patients and female commercial sex workers （FSWs） working at recreation centers or being detained in a women education center to identify the relationship between condom use and power relation in male and female respondents using bivariate and multiple regression analysis. Results A significant relationship was identified between power relation and female condom use, the higher the score of power relations, the higher frequency the condom use, but no similar result was found in males. Females got a higher score of power relation than males. Conclusions Power relation is one of the factors that influence condom use, which should be considered when relevant theories are used to study the rate of condom use. It is worthwhile exploring the relationship between safe sex and power relation in spouses and regular sex partners when interventions are adopted to prevent HIV/AIDS spreading from high risk groups to the general population.
文摘Wang: Speaking of Sino-U. S. relations, actually it touches upon great power relationship. The current Iraqi crisis became a focus in UN. There is a clear demarcation line between those countries supporting a war and those countries in favor of weapons inspections within
文摘This study explored the construction of power relations in the cognitive assessment of older adults within the Chinese clinical context.Data is derived from audio and video recordings that nine older adults produced in the cognitive assessment of the Chinese version of the Montreal Cognitive Assessment-Basic(MoCA-B),which were then annotated and analyzed from a multimodal pragmatic perspective.The study reveals that examiners and older adults employed various speech acts to achieve distinct communicative goals,with power relations between them being reflected through these speech acts.Examiners tend to claim high power,utilizing discourse strategies such as request,interruption,evaluation,rhetorical questions,and directive speech acts.In contrast,older adults assert high power through directive speech acts,rhetorical questions,and interruptions.Both parties also exhibit low power by using confirming questions and explanations.Additionally,gestures,smiles,prosody features,and other non-verbal communicative resources are synergistically employed to exercise power.The interactive mechanism of constructing power relations reveals that age affects older adults’power relations construction even in a professional setting of the Chinese context.The negotiation between the advanced age of older adults and the expertise of examiners jointly shapes power relations in their interactions.
文摘The year of 2016 witnessed the balance of internal and external situations, calm and steady actions and proper planning in major power diplomacy with Chinese characteristics. Those were reflected in the success of the G20 summit, the vigorous promotion of the"One Belt, One Road"(B&R) Initiative and the active promotion of international cooperation on development, which acquired positive response and general agreement from the international community and made special contributions to building a more just and reasonable international order.Those were also reflected in the active management of major power relations and sound responses to the changing situation in the surrounding area to create good external environment for domestic development. In addition, further expansion and defending of overseas interests set higher standards for Chinese diplomacy. Having been pushed by the era to the forefront, China is performing its responsibility as a major power in a peculiar way and will certainly make greater contributions to world peace and development.
文摘To cope with the current crisis and tensions full-filled China-US relationship, Chinese President Xi Jinping put forward the concept of building a new model of China-US big power relations, which the US agrees. Yet the new model won a heated discussion. In China this new model was evaluated positively and optimistically, while in the US it was perceived as a strategic challenge or even a threat. In the present article, the author proposes that this new model of China-US big power relations is more like a symbolic sign in foreign affairs rather than a strategic challenge or a threat or an effective and workable mechanism at this moment, and meanwhile analyses this view from diachronic and semiotic perspectives. The analyses reveal that the new model functions as a symbolic sign, signifying to the world that conceptually the two big powers have a good and harmonious relationship.
基金the initial results for the National Social Science Fund West Project entitled“The strategic risks and systematic solutions for The Belt and Road Initiative”(16XGJ010)scientific research project for Beijing Language and Culture University(central-government-sponsored universities basic scientific research special funds 16YJ010013)
文摘Over the past two years, India's Modi government has demonstrated the following features: focusing on the goals of becoming a great power and shaping India's South Asian dominance, expanding the scope of diplomatic strategy, emphasizing the role of soft power and focusing on self-development as well as external environment. Modi's great power strategy is deeply influenced by the Indian realistic international political outlook and, to a certain extent, reflects the governing philosophy of the Bharatiya Janata Party. The great power strategy is Modi's governing foundation and governing style, embedding Modi distinctive personal style. Under the influence of the great power strategy, China and India have increased their economic cooperation scope, widening the forms of public diplomacy, with an obvious geopolitical collision; India is taking more measures to check China.
文摘As a noted modern American playwright, David Mamet attracts wide attention from the readers, the audience, as well as the academic circle with his fascinating language features. In his plays, in order to achieve their individual goals, the male characters, applying the discursive power with language as weapon, endeavor to build a new structure of power. It aims to analyze A Life in the Theatre, with such discourse-analysis mechanics as turn-taking and politeness strategy, to examine the power relations between the two male characters in the play, and finally to explain how discourse influence and alter the power relations in reality.
基金Supported by the National Natural Science Foundation of China(21121064,21206002,21376016)
文摘The impeller configuration with a six parabolic blade disk turbine below two down-pumping hydrofoil propellers, identified as PDT + 2CBY, was used in this study. The effect of the impeller diameter D, ranging from0.30 T to 0.40T(T as the tank diameter), on gas dispersion in a stirred tank of 0.48 m diameter was investigated by experimental and CFD simulation methods. Power consumption and total gas holdup were measured for the same impeller configuration PDT + 2CBY with four different D/T. Results show that with D/T increases from 0.30 to 0.40, the relative power demand(RPD) in a gas–liquid system decreases slightly. At low superficial gas velocity VSof 0.0078 m·s-1, the gas holdup increases evidently with the increase of D/T. However, at high superficial gas velocity, the system with D/T = 0.33 gets a good balance between the gas recirculation and liquid shearing rate, which resulted in the highest gas holdup among four different D/T. CFD simulation based on the two-fluid model along with the Population Balance Model(PBM) was used to investigate the effect of impeller diameter on the gas dispersion. The power consumption and total gas holdup predicted by CFD simulation were in reasonable agreement with the experimental data.
基金Project supported by the National Basic Research Program of China (2006CB601101)the National High Technology Research and Development Program of China (2007AA03Z440)the National Natural Science Foundation of China (50731007)
文摘Magnetic properties and structures in La1-zPrz(Fe0.895–xCoxSi0.105)13 (x=0.07, 0.08; z=0, 0.2, 0.4) compounds were investigated. When Pr and Co substituted for La and Fe, the Curie temperature of the compounds was adjusted to around room temperature. The magnetic phase transition was driven from first-order to second-order due to Co substitution. As a second-order phase transition material, the MCE of La0.6Pr0.4(Fe0.825Co0.07Si0.105)13, whose relative cooling power was 175 J/kg under a field change of 2 T, ...
基金Project supported by the Key Program of the National Natural Science Foundation of China (Grant No. 50537030)the National Natural Science Foundation of China (Grant Nos. 61072012 and 61172009)+1 种基金the Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos. 61104032 and 60901035)the Tianjin Municipal Natural Science Foundation (Grant No. 12JCZDJC21100)
文摘To investigate whether and how manual acupuncture（MA） modulates brain activities,we design an experiment where acupuncture at acupoint ST36 of the right leg is used to obtain electroencephalograph（EEG） signals in healthy subjects.We adopt the autoregressive（AR） Burg method to estimate the power spectrum of EEG signals and analyze the relative powers in delta（0 Hz-4 Hz）,theta（4 Hz-8 Hz）,alpha（8 Hz-13 Hz）,and beta（13 Hz-30 Hz） bands.Our results show that MA at ST36 can significantly increase the EEG slow wave relative power（delta band） and reduce the fast wave relative powers（alpha and beta bands）,while there are no statistical differences in theta band relative power between different acupuncture states.In order to quantify the ratio of slow to fast wave EEG activity,we compute the power ratio index.It is found that the MA can significantly increase the power ratio index,especially in frontal and central lobes.All the results highlight the modulation of brain activities with MA and may provide potential help for the clinical use of acupuncture.The proposed quantitative method of acupuncture signals may be further used to make MA more standardized.
基金the Opening Foun-dation of Guangxi Key Laboratory for the Advance Materi-als and New Preparation Technology
文摘The lattice parameter and magnetocaloric properties of three samples of LaFe11.2Co0.7Si1.1-xGax with x = 0, 0.03 and 0.05 have been investigated by X-ray powder diffraction and magnetization measurements. The lattice parameter increases slightly and the Curie temperature increases somewhat with increasing gallium content. However, a small amount of Ga doping into the sample decreases the magnetic entropy change of the sample. All the samples remain in the first-order magnetic phase transition. The most striking effect of the Ga doping is that the cooling capacity in the samples increases significantly. The maximum magnetic entropy change, ASM and the cooling capacity of the sample LaFe11.2Co0.7Si1.07Ga0.03 are 11.9 J·kg^-1·K^-1 and 254.8 J·kg^-1, respectively.
基金Project supported by the National Natural Science Foundation of China (50572013)
文摘We reported the magnetic properties and magnetocaloric effects(MCE) of(La0.8Ho0.2)2/3Ca1/3MnO3 and(La0.5Ho0.5)2/3Ca1/3MnO3 nanoparticles by sol-gel technique.With this method,we were able to obtain the samples with particle diameters ranging from 50 to 200 nm.In the(La1-xHox)2/3Ca1/3MnO3 compound,an external magnetic field induced a magnetic transition from an paramagnetic phase to a ferromagnetic phase above Ts=105-135 K,leading to magnetocaloric effects.The maximum value of ΔSM was 1.19 J/(kg·K) at 100 K and 2.03 J/(kg·K) at 152 K for a magnetic field change of 5 T.Because both samples had large relative cooling power(RCP) and wide δTFWHM,the study on systems with the(La1-xHox)2/3Ca1/3MnO3-related magnetic transitions may open an important field in searching good magnetic materials.
基金the research project of China Earthquake Administration—Earthquake Science and Technology Star Fire Plan(XH2018035Y)Seismic Regime Tracking Project of CEA(2020010410).
文摘Co-seismic gas leakage usually occurs on the edge of seismic faults in petroliferous basins,and it may have an impact on the local environment,such as the greenhouse effect,which can cause thermal infrared brightness anomalies.Using wavelet transform and power spectrum estimation methods,we processed brightness temperature data from the Chinese geostationary meteorological satellite FY-C/E.We report similarities between the co-seismic thermal infrared brightness(CTIB)anomalies before,during and after earthquakes that occurred at the edges of the Sichuan,Tarim,Qaidam,and Junggar basins surrounding the North and East of the Qinghai–Tibet Plateau in western China.Additionally,in each petroliferous basin,the area of a single CTIB anomaly accounted for 50%to 100%of the basin area,and the spatial distribution similarities in the CTIB anomalies existed before,during and after these earthquakes.To better interpret the similarities,we developed a basin warming effect model based on geological structures and topography.The model suggests that in a petroliferous basin with a subsurface gas reservoir,gas leakage could strengthen with the increasing stress before,during,and even after an earthquake.The accumulation of these gases,such as the greenhouse gases CH4 and CO2,results in the CTIB anomalies.In addition,we conclude that the CTIB anomalies are strengthened by the high mountains(altitude^5000 m)around the basins and the basins’independent climatic conditions.This work provides a new perspective from which to understand the CTIB anomalies in petroliferous basins surrounding the North and East of the Qinghai–Tibet Plateau.
基金Supported by the Zhejiang Provincial Natural Science Foundation of China(LY16B060003)the National Natural Science Foundation of China(21776246)
文摘The effects of impeller type, stirring power, gas flow rate, and liquid concentration on the gas–liquid mixing in a shear-thinning system with a coaxial mixer were investigated by experiment, and the overall gas holdup, relative power demand, and volumetric mass transfer coefficient under different conditions were compared. The results show that, the increasing stirring power or gas flow rate is beneficial in promoting the overall gas holdup and volumetric mass transfer coefficient, while the increasing system viscosity weakens the mass transfer in a shearing–thinning system. Among the three turbines, the six curved-blade disc turbine(BDT-6) exhibits the best gas pumping capacity; the six 45° pitched-blade disc turbine(PBDT-6) has the highest volumetric mass transfer coefficient at the same unit volume power.
基金supported by the Polish Government and WBI(Belgium)in a Frame of Mutual Scientific Exchange Visits between WBI and Polish Ministry under project with reference numbers 14794/PVB/BE.POL/AN/an/2016/28611 and Rhea 2015/245812
文摘A systematic investigation on the structural, magnetic and magnetocaloric properties of Pr_（0.6）Sr_（0.4-x）Ag_xMnO_3（x=0.05 and 0.1） manganites was reported. Rietveld refinements of the X-ray diffraction patterns confirmed that all samples were single phase and crystallized in the orthorhombic structure with Pnma space group. Magnetic measurements in a magnetic applied field of 0.01T revealed that the ferromagnetic-paramagnetic transition temperature T_C decreased from about 293 to 290 K with increasing silver content from x=0.05 to 0.1. The reported magnetocaloric entropy change and relative cooling power for both samples were considerably remarkable with a △S_（max） value of 1.9 J/（kg·K）and maximum RCP values of 100 J/kg, under a magnetic field change（？μ0H） equal to 1.8T. The analysis of the universal curves gave an evidence of a second order magnetic transition for the studied samples. The magnetic field influence on both the magnetic entropy change and the relative cooling power was also studied and discussed.
基金the National Research Foundation of Korea grant the Korean government(No.2018R1D1A1B07046937)。
文摘The height of total entropy(S)for a magnetic refrigerant material is essentially concerned with the magnetic and structural transitions.However,the participation of such transitions in layered materials is not well understood.Therefore,the purpose of this work is to investigate the interplay between double layer lattice with their single perovskite counterpart,to achieve optimal magnetocaloric performance.A series of self-doped Pr_(1.4+x)Sr_(1.6-x)Mn_(2)O_(7)(0.0≤x≤0.5)Ruddlesden-Popper(R-P)perovskite have been prepared through the solid-state sintering method.With increasing the Pr-stoichiometry,the lattice faults have increased and the double layer lattice dramatically disintegrates into single perovskite structure.Due to the reduction of bilayer R-P phase into single perovskite the spin crossover occurs from weak bilayer(T=304 K)interactions towards the strong three-dimensional(T=308 K)interactions respectively.This series consistently develops thermomagnetic irreversibility in zero-field cooled(ZFC)-field cooled(FC)magnetization,which is indicative of a spin-glass state.The glassy nature has been ascribed collectively to the lattice strain produced because of dislocations and to an antiferromagnetic phase segregated at the surface.The maximum value of temperature average entropy change(TEC)and adiabatic temperature(ΔT)has enhanced nearly by 4 folds from 0.53 J kg^(-1)K^(-1),0.59 K(for x=0.0)up to 1.85 J kg^(-1)K^(-1),10 K(for x=0.5)at 2.5 T,respectively.Additionally,the room temperature relative cooling power has improved from 26.94 J/kg up to 77.84 J/kg with an applied field of 2.5 T.Our findings in this work suggest that the controlled reduction of double layer lattice into single perovskite and/or existence of both phases simultaneously in bilayer R-P manganites may be very effective in obtaining the desirable characteristics of magnetocaloric effects.
