In this editorial,I comment on three articles published in the recent issue of the World Journal of Gastrointestinal Oncology.Hepatocellular carcinoma(HCC)is an important public health concern,and there are three arti...In this editorial,I comment on three articles published in the recent issue of the World Journal of Gastrointestinal Oncology.Hepatocellular carcinoma(HCC)is an important public health concern,and there are three articles on the theme of HCC in this issue.I focus on the articles by Mu et al,Chu et al,and Ma et al for this editorial.While these articles may be considered as low-quality evidence,and the results cannot be generalized to non-hepatitis-B or C virus patients,the discussion of the results is important.In addition,though all the articles are from China,the relevance of the results is not minuscule.As resection is the main form of curative treatment modality owing to a donor liver shortage,surgeons need to be aware that preoperative long-course antiviral therapy can improve clinical outcomes by reducing postoperative liver dysfunction and recurrence of HCC following resection.Similarly,patients with super-giant HCC(defined as≥15 cm diameter)should also be carefully considered for liver resection,and if it is unresectable upfront,then a combination of liver-directed therapy and systemic therapy may downstage HCC.If,following downstaging,the patient qualifies for liver resection based on locally prevalent resectability criteria,then such therapy is labelled as conversion(from unresectable to resectable)therapy.In unresectable patients treated by a combination of treatment options,serological markers like neutrophil-to-lymphocyte ratio and alpha-fetoprotein are reported to predict treatment responses,thus enabling personalized medicine.展开更多
Urea as a source of cheap non-protein nitrogen is used to adulterate fish and meat meals which are basic components of broiler diets. The present study was carried out to elucidate the effects of urea on weight gain, ...Urea as a source of cheap non-protein nitrogen is used to adulterate fish and meat meals which are basic components of broiler diets. The present study was carried out to elucidate the effects of urea on weight gain, and hematological and biochemical profiles. A total of 48 broiler chicks were randomly allotted into 4 groups, designated Groups 1, 2, 3 and 4 of 12 birds each. Birds in Groups 2, 3 and 4 were fed on diets containing urea at the levels of 1%, 2.5% and 4%, respectively. Birds in Group 1 served as control and were not exposed to urea. Experimentation period was for 3 weeks and experiment was terminated when birds were 42 days of age. Body weight of all intoxicated birds at the various intervals was significantly decreased in comparison with that of the untreated control. Compared with control, all intoxicated broilers manifested significant (P ≤ 0.05) decrease in all hematological parameters involving erythrocytic and total leucocytic counts, Hemoglobin (Hb) and Packed Cell Volume (PCV) on a dose- and time-pattern. In comparison with the control levels, biochemical profile of the intoxicated birds disclosed significant decrease in blood glucose level and significant increase in serum uric acid, urea, Alkaline Phosphatase (ALP) and Lactate Dehydrogenase (LDH) levels. Based upon the present data, it was concluded that the addition of urea to broiler diets bears serious sequences concerning the general health condition, performance, weight gain, and hematological and biochemical profiles.展开更多
Modeling for nitritation process was discussed and analyzed quantitatively for the factors that influence nitrite accumulation. The results indicated that pH, inorganic carbon source and Hydraulic Retention Time(HRT) ...Modeling for nitritation process was discussed and analyzed quantitatively for the factors that influence nitrite accumulation. The results indicated that pH, inorganic carbon source and Hydraulic Retention Time(HRT) as well as biomass concentration are the main factors that influenced the conversion ratio of ammonium to nitrite. A constant high pH can lead to a high nitritation rate and results in high conversion ratio on condition that free ammonia inhibition do not happen. In a CSTR system, without pH control, this conversion ratio can be monitored by pH variation in the reactor. The pH goes down far from the inlet level means a strongly nitrite accumulation. High concentration of alkalinity can promoted the conversion ratio by means of accelerating the nitritation rate through providing sufficient inorganic carbon source(carbon dioxide). When inorganic carbon source was depleted, the nitritation process stopped. HRT adjustment could be an efficient way to make the nitritation system run more flexible, which to some extent can meet the requirements of the fluctuant of inlet parameters such as ammonium concentration, pH, and temperature and so on. Biomass concentration is the key point, especially for a CSTR system in steady state, which was normally circumscribed by the characteristics of bacteria and may also affected by aeration mode and can be increased by prolonging the HRT on the condition of no nitrate accumulation when no recirculation available. The higher the biomass concentration is, the better the nitrite accumulation can be obtained.展开更多
With a new apparatus designed and assembled by ourselves, the matrix potential of non-saturated loess was firstly measured and studied during methane hydrate formation processes. The experimental results showed that d...With a new apparatus designed and assembled by ourselves, the matrix potential of non-saturated loess was firstly measured and studied during methane hydrate formation processes. The experimental results showed that during two formation processes, the matrix potential changes of the loess all presented a good linear relationship with water conversion ratios. In addition, although it was well known that the secondary gas hydrate formation was easier than the initial, our experimental results showed that the initial hydrate formation efficiency in non-saturated loess was higher than that of the secondary.展开更多
Freely movable wave energy converters(WECs) will greatly improve their adaptability to the marine environment.In this paper, a dual-mode oscillating water column(OWC) WEC with potential sailing capability is proposed....Freely movable wave energy converters(WECs) will greatly improve their adaptability to the marine environment.In this paper, a dual-mode oscillating water column(OWC) WEC with potential sailing capability is proposed. By opening and closing a gate on the side facing the waves, the WEC converts wave energy in the vertical duct(called VD mode) with low sailing resistance or in the backward bend duct(called BBD mode) with high sailing resistance.A small model and a medium model were designed and manufactured. The capture width ratio(CWR) of the small model in the two modes was experimentally studied. The CWR under bidirectional airflow and conversion characteristics under unidirectional airflow of the medium model in the BBD mode were obtained. Tests of the small model show that the peak CWR is 145.2% under regular waves and 90.1% under random waves in BBD mode, and in VD mode the peak CWR is about 60% of that in the BBD mode. Tests of the medium model show that the peak CWR is 228.96% under regular waves, the maximum wave-to-battery efficiency is 63.36% under regular waves and 30.17%under random waves, respectively.展开更多
This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for rice by data mining method based on data of"3414 fertilizer field trials"of rice ...This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for rice by data mining method based on data of"3414 fertilizer field trials"of rice by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of rice for plot was that,Y N≈a+b×optimum yield+c×optimum fertilizer amount of K,Y P≈a+b×optimum yield,Y K≈a respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships:①no significant relationships:25,of which 14 were soil nutrients and 9 were environmental factors,the results showed that soil nutrients and environmental factors had little effect on nutrient yield ratio and fertilizer utilization ratio;②consistent significant relationships:2,one was that yield ratio and utilization ratio of N were positively correlated with the optimum production,explaining the importance of N for production,the other was that yield ratio and utilization ratio of P had a significantly positive correlation with conversion rate and utilization ratio of N,illustrating that nitrogen and phosphorus had mutual promotion;③contrary significant relationships:5,these showed as negative correlations of fertilizer utilization ratio and positive correlation of nutrient conversion ratio;④complementary significant relationships:22,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the index of fertilizer efficiency in one season,while the nutrient conversion rate was the index of fertilizer efficiency in more seasons,which showed that the fertilizer utilization rate was significantly correlated,or the nutrient conversion rate was significantly correlated.展开更多
This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for wheat by data mining method based on data of"3414 fertilizer field trials"of whea...This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for wheat by data mining method based on data of"3414 fertilizer field trials"of wheat by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of wheat for plot was that,Y N≈a+b×optimum nitrogen application amount+c×optimum fertilizer amount of K+d×rainfall in growth season,Y P≈a+b×optimum fertilizer amount of K+c×rainfall in growth season,Y K≈a+b×temperature in growth season+c×rainfall in growth season-d×optimum yield-e×optimum nitrogen application amount,respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships.No significant relationships:13,of which 8 were soil nutrients,the results showed that soil nutrients had little effect on nutrient conversion rate and fertilizer utilization ratio;consistent significant relationships:4,they were all nitrogen and phosphorus,explaining the importance of nitrogen and phosphorus;contrary significant relationships:6,they were all nitrogen and phosphorus,illustrating that phosphorus and nitrogen had inhibitory effect;complementary significant relationships:31,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the measuring index of fertilizer efficiency in one season,while the nutrient conversion rate was the measuring index of fertilizer efficiency in more seasons.It showed that the fertilizer utilization rate was significantly correlated,or the nutrient conversion rate was significantly correlated.展开更多
This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for maize by data mining method based on data of"3414 fertilizer field trials"of maiz...This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for maize by data mining method based on data of"3414 fertilizer field trials"of maize by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of maize for plot was that,Y N≈a+b×optimum yield,Y P≈a+b×optimum yield-c×optimum nitrogen application amount-d×optimum potassium application amount,Y K≈a-b×optimum nitrogen application amount-c×temperature in growth season-d×rainfall in growth season,respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships.No significant relationships:22,of which 16 were soil nutrients and 5 were environmental factors,the results showed that soil nutrients and environmental factors had little effect on nutrient conversion rate and fertilizer utilization ratio;consistent significant relationships:14,illustrating that conversion rate and utilization ratio of maize were consistent in most cases,and it was because that maize was planted for a long term,and its fertilizer absorption law was basically stable;contrary significant relationships:0,illustrating that there was no reverse relationship between conversion rate and utilization ratio of maize;complementary significant relationships:18,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the measuring index of fertilizer efficiency in one season,while the nutrient conversion rate was the measuring index of fertilizer efficiency in more seasons.It showed that the fertilizer utilization ratio was significantly correlated,or the nutrient conversion rate was significantly correlated.展开更多
In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter(WEC) based on the linear theory of water waves. The generator power take-off(PTO) system is mod...In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter(WEC) based on the linear theory of water waves. The generator power take-off(PTO) system is modeled as a combination of a linear viscous damping and a linear spring. Using the frequency domain method, the optimal damping coefficient of the generator PTO system is derived to achieve the optimal conversion efficiency(capture width ratio).Based on the potential flow theory and the higher-order boundary element method(HOBEM), we constructed a threedimensional model of double-float WEC to study its hydrodynamic performance and response in the time domain. Only the heave motion of the two-body system is considered and a virtual function is introduced to decouple the motions of the floats. The energy conversion character of the double-float WEC is also evaluated. The investigation is carried out over a wide range of incident wave frequency. By analyzing the effects of the incident wave frequency, we derive the PTO's damping coefficient for the double-float WEC's capture width ratio and the relationships between the capture width ratio and the natural frequencies of the lower and upper floats. In addition, it is capable to modify the natural frequencies of the two floats by changing the stiffness coefficients of the PTO and mooring systems. We found that the natural frequencies of the device can directly influence the peak frequency of the capture width, which may provide an important reference for the design of WECs.展开更多
In situ catalytic conversion of biomass fast pyrolysis vapors was carried out on HZSM-5 with varying Si/Al ratios(ranging from 20 to 300) at 450 °C. The effects of Si/Al ratios of HZSM-5 zeolites on the distribut...In situ catalytic conversion of biomass fast pyrolysis vapors was carried out on HZSM-5 with varying Si/Al ratios(ranging from 20 to 300) at 450 °C. The effects of Si/Al ratios of HZSM-5 zeolites on the distribution of biomass fast pyrolysis products and carbon deposits on catalysts were investigated. It was quite remarkable that after in situ catalytic conversion the amount of light phenols and hydrocarbons increased significantly while that of heavy phenols decreased a lot. Besides, the yield of cyclopentenones with relatively low oxygen content generally increased. It also indicated that as the Si/Al ratios of HZSM-5 increased, the amount of hydrocarbons and light phenols was found to drop greatly. The amount of carbon deposits was found to be around 8.5% with the exception of HZSM-5 with the Si/Al ratio of 300,which is much lower. Moreover, the carbon deposits yield dropped gradually with increasing Si/Al ratios of HZSM-5.Calcination of spent catalysts at 600 °C helped to restore the catalytic activity to a large extent despite a relatively lower efficiency of deoxygenation. Results indicated that HZSM-5 with relatively high acidity displayed great catalytic performance.展开更多
Point absorber wave energy device with multiple degrees of freedom(DOF) is assumed to have a better absorption ability of mechanical energy from ocean waves. In this paper, a coaxial symmetric articulated point absorb...Point absorber wave energy device with multiple degrees of freedom(DOF) is assumed to have a better absorption ability of mechanical energy from ocean waves. In this paper, a coaxial symmetric articulated point absorber wave energy converter with two degrees of freedom is presented. The mechanical equations of the oscillation buoy with power take-off mechanism(PTO) in regular waves are established. The three-dimensional numerical wave tank is built in consideration of the buoy motion based upon the CFD method. The appropriate simulation elements are selected for the buoy and wave parameters. The feasibility of the CFD method is verified through the contrast between the numerical simulation results of typical wave conditions and test results. In such case, the buoy with single DOF of heave, pitch and their coupling motion considering free(no PTO damping) and damped oscillations in regular waves are simulated by using the verified CFD method respectively. The hydrodynamic and wave energy conversion characteristics with typical wave conditions are analyzed. The numerical results show that the heave and pitch can affect each other in the buoy coupling motion, hydrodynamic loads, wave energy absorption and flow field.The total capture width ratio with two coupled DOF motion is higher than that with a single DOF motion. The wave energy conversion of a certain DOF motion may be higher than that of the single certain DOF motion even though the wave is at the resonance period. When the wave periods are high enough, the interaction between the coupled DOF motions can be neglected.展开更多
The green and red up-conversion emissions centred at about 534, 549 and 663 nm of wavelength, corresponding respectively to the ^2H11/2 → ^4I15/2, ^4S3/2 → ^4I15/2 and ^4F9/2 → ^4I15/2 transitions of Er^3+ ions, h...The green and red up-conversion emissions centred at about 534, 549 and 663 nm of wavelength, corresponding respectively to the ^2H11/2 → ^4I15/2, ^4S3/2 → ^4I15/2 and ^4F9/2 → ^4I15/2 transitions of Er^3+ ions, have been observed for the Er^3+-doped silicate glass excited by a 978 nm semiconductor laser beam. Excitation power dependent behaviour of the up-conversion emission intensity indicates that a two-photon absorption up-conversion process is responsible for the green and red up-conversion emissions. The temperature dependence of the green up-conversion emissions is also studied in a temperature range of 296-673 K, which shows that Er^3+-doped silicate glass can be used as a sensor in high-temperature measurement.展开更多
The studies for raising potash feldspar utilization ratio by physical, biological and chemical methods are carried out in laboratory and the results are presented. It is shown that calcinatory and biological methods h...The studies for raising potash feldspar utilization ratio by physical, biological and chemical methods are carried out in laboratory and the results are presented. It is shown that calcinatory and biological methods have positive effects on conversion of K in potash feldspar into water-soluble form, but the conversion is low; chemical method can change most of insoluble potassium into available form, and might be significant in industry to some extent.展开更多
Experiments were conducted on risers with different mass ratios to study the effect of mode conversion and spanwise correlation. The slenderness ratio of the riser model was set as 169, and the Reynolds numbers are 16...Experiments were conducted on risers with different mass ratios to study the effect of mode conversion and spanwise correlation. The slenderness ratio of the riser model was set as 169, and the Reynolds numbers are 1600-14400. The dynamic responses of riser models versus reduced velocity were analyzed, and the spanwise displacement, frequency,and trajectory of the mode conversion from the lower to the higher mode were explored. The results revealed that the riser model with a higher mass ratio excites a higher number of modes. The conversion region of multi-mode competition exists and narrows with the increasing mass ratio. Mode conversion is continuous and manifests as the transmission of peaks and troughs in mode shape: the peaks and troughs of mode shape move up in the mode stable development region and move down in the mode conversion region. The single-mode dominating vibration exhibits a standing wave feature, and the traveling wave feature is significant in the mode conversion region. Furthermore, the frequency jump is always transmitted from the trough to the peak of the mode shape, and finally, all the axial positions vibrate at the same frequency. The trajectory in the mode conversion region deviates from the 8-shape and recovers the standard8-shape at the middle and late stages of the mode stable development region.展开更多
The effect of fishmeal quality on growth,feed conversion ratio and protein digestibility was studied in a growth experiment with shrimp and red seabream.The shrimp and fish were fed three diets varing in the quality o...The effect of fishmeal quality on growth,feed conversion ratio and protein digestibility was studied in a growth experiment with shrimp and red seabream.The shrimp and fish were fed three diets varing in the quality of the fishmeal used in the respective feeds: low quality fish meal,good quality fish meal,and Peru fish meal.The experiment lasted for 2 months.The shrimp and fish fed the feed with good quality fish meal showed significantly better feed conversion ratio,weight gain rate,protein digestibility than the other groups.展开更多
文摘In this editorial,I comment on three articles published in the recent issue of the World Journal of Gastrointestinal Oncology.Hepatocellular carcinoma(HCC)is an important public health concern,and there are three articles on the theme of HCC in this issue.I focus on the articles by Mu et al,Chu et al,and Ma et al for this editorial.While these articles may be considered as low-quality evidence,and the results cannot be generalized to non-hepatitis-B or C virus patients,the discussion of the results is important.In addition,though all the articles are from China,the relevance of the results is not minuscule.As resection is the main form of curative treatment modality owing to a donor liver shortage,surgeons need to be aware that preoperative long-course antiviral therapy can improve clinical outcomes by reducing postoperative liver dysfunction and recurrence of HCC following resection.Similarly,patients with super-giant HCC(defined as≥15 cm diameter)should also be carefully considered for liver resection,and if it is unresectable upfront,then a combination of liver-directed therapy and systemic therapy may downstage HCC.If,following downstaging,the patient qualifies for liver resection based on locally prevalent resectability criteria,then such therapy is labelled as conversion(from unresectable to resectable)therapy.In unresectable patients treated by a combination of treatment options,serological markers like neutrophil-to-lymphocyte ratio and alpha-fetoprotein are reported to predict treatment responses,thus enabling personalized medicine.
文摘Urea as a source of cheap non-protein nitrogen is used to adulterate fish and meat meals which are basic components of broiler diets. The present study was carried out to elucidate the effects of urea on weight gain, and hematological and biochemical profiles. A total of 48 broiler chicks were randomly allotted into 4 groups, designated Groups 1, 2, 3 and 4 of 12 birds each. Birds in Groups 2, 3 and 4 were fed on diets containing urea at the levels of 1%, 2.5% and 4%, respectively. Birds in Group 1 served as control and were not exposed to urea. Experimentation period was for 3 weeks and experiment was terminated when birds were 42 days of age. Body weight of all intoxicated birds at the various intervals was significantly decreased in comparison with that of the untreated control. Compared with control, all intoxicated broilers manifested significant (P ≤ 0.05) decrease in all hematological parameters involving erythrocytic and total leucocytic counts, Hemoglobin (Hb) and Packed Cell Volume (PCV) on a dose- and time-pattern. In comparison with the control levels, biochemical profile of the intoxicated birds disclosed significant decrease in blood glucose level and significant increase in serum uric acid, urea, Alkaline Phosphatase (ALP) and Lactate Dehydrogenase (LDH) levels. Based upon the present data, it was concluded that the addition of urea to broiler diets bears serious sequences concerning the general health condition, performance, weight gain, and hematological and biochemical profiles.
文摘Modeling for nitritation process was discussed and analyzed quantitatively for the factors that influence nitrite accumulation. The results indicated that pH, inorganic carbon source and Hydraulic Retention Time(HRT) as well as biomass concentration are the main factors that influenced the conversion ratio of ammonium to nitrite. A constant high pH can lead to a high nitritation rate and results in high conversion ratio on condition that free ammonia inhibition do not happen. In a CSTR system, without pH control, this conversion ratio can be monitored by pH variation in the reactor. The pH goes down far from the inlet level means a strongly nitrite accumulation. High concentration of alkalinity can promoted the conversion ratio by means of accelerating the nitritation rate through providing sufficient inorganic carbon source(carbon dioxide). When inorganic carbon source was depleted, the nitritation process stopped. HRT adjustment could be an efficient way to make the nitritation system run more flexible, which to some extent can meet the requirements of the fluctuant of inlet parameters such as ammonium concentration, pH, and temperature and so on. Biomass concentration is the key point, especially for a CSTR system in steady state, which was normally circumscribed by the characteristics of bacteria and may also affected by aeration mode and can be increased by prolonging the HRT on the condition of no nitrate accumulation when no recirculation available. The higher the biomass concentration is, the better the nitrite accumulation can be obtained.
基金supported by the CAS Knowledge Innovation Key Project (Grant No. KZCX2-YW-330)the National Science Fund Fostering Talents in Basic Research to Glaciology and Geocryology (Grant No. J0630966)the Training Fund of State Key Laboratory of Frozen Soil Engineering of Chinese Academy of Sciences (Grant No. 52YOSF102)
文摘With a new apparatus designed and assembled by ourselves, the matrix potential of non-saturated loess was firstly measured and studied during methane hydrate formation processes. The experimental results showed that during two formation processes, the matrix potential changes of the loess all presented a good linear relationship with water conversion ratios. In addition, although it was well known that the secondary gas hydrate formation was easier than the initial, our experimental results showed that the initial hydrate formation efficiency in non-saturated loess was higher than that of the secondary.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51879253 and U20A20106)。
文摘Freely movable wave energy converters(WECs) will greatly improve their adaptability to the marine environment.In this paper, a dual-mode oscillating water column(OWC) WEC with potential sailing capability is proposed. By opening and closing a gate on the side facing the waves, the WEC converts wave energy in the vertical duct(called VD mode) with low sailing resistance or in the backward bend duct(called BBD mode) with high sailing resistance.A small model and a medium model were designed and manufactured. The capture width ratio(CWR) of the small model in the two modes was experimentally studied. The CWR under bidirectional airflow and conversion characteristics under unidirectional airflow of the medium model in the BBD mode were obtained. Tests of the small model show that the peak CWR is 145.2% under regular waves and 90.1% under random waves in BBD mode, and in VD mode the peak CWR is about 60% of that in the BBD mode. Tests of the medium model show that the peak CWR is 228.96% under regular waves, the maximum wave-to-battery efficiency is 63.36% under regular waves and 30.17%under random waves, respectively.
基金Major Scientific and Technological Projects in Guangxi(GUIKE AA17204077)Special Project of Guangxi Science and Technology Base and Talent(GUIKE AD18126012)+2 种基金First-class Discipline(Geography)Construction Project in GuangxiSpecial Funds for"Guangxi Bagui Scholars"Collaborative Innovation Task of Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences—Integration and Demonstration of Green and Efficient Agricultural Technology Innovation in Danjiangkou Water Conservation Area(CAAS-XTCX2016015).
文摘This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for rice by data mining method based on data of"3414 fertilizer field trials"of rice by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of rice for plot was that,Y N≈a+b×optimum yield+c×optimum fertilizer amount of K,Y P≈a+b×optimum yield,Y K≈a respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships:①no significant relationships:25,of which 14 were soil nutrients and 9 were environmental factors,the results showed that soil nutrients and environmental factors had little effect on nutrient yield ratio and fertilizer utilization ratio;②consistent significant relationships:2,one was that yield ratio and utilization ratio of N were positively correlated with the optimum production,explaining the importance of N for production,the other was that yield ratio and utilization ratio of P had a significantly positive correlation with conversion rate and utilization ratio of N,illustrating that nitrogen and phosphorus had mutual promotion;③contrary significant relationships:5,these showed as negative correlations of fertilizer utilization ratio and positive correlation of nutrient conversion ratio;④complementary significant relationships:22,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the index of fertilizer efficiency in one season,while the nutrient conversion rate was the index of fertilizer efficiency in more seasons,which showed that the fertilizer utilization rate was significantly correlated,or the nutrient conversion rate was significantly correlated.
基金Collaborative Innovation Task of Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences—Integration and Demonstration of Green and Efficient Agricultural Technology Innovation in Danjiangkou Water Conservation Area(CAAS-XTCX2016015)Major Scientific and Technological Projects in Guangxi(GUIKE AA17204077)+2 种基金Special Project of Guangxi Science and Technology Base and Talent(GUIKE AD18126012)First-class Discipline(Geography)Construction Project in GuangxiSpecial Funds for"Guangxi Bagui Scholars".
文摘This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for wheat by data mining method based on data of"3414 fertilizer field trials"of wheat by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of wheat for plot was that,Y N≈a+b×optimum nitrogen application amount+c×optimum fertilizer amount of K+d×rainfall in growth season,Y P≈a+b×optimum fertilizer amount of K+c×rainfall in growth season,Y K≈a+b×temperature in growth season+c×rainfall in growth season-d×optimum yield-e×optimum nitrogen application amount,respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships.No significant relationships:13,of which 8 were soil nutrients,the results showed that soil nutrients had little effect on nutrient conversion rate and fertilizer utilization ratio;consistent significant relationships:4,they were all nitrogen and phosphorus,explaining the importance of nitrogen and phosphorus;contrary significant relationships:6,they were all nitrogen and phosphorus,illustrating that phosphorus and nitrogen had inhibitory effect;complementary significant relationships:31,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the measuring index of fertilizer efficiency in one season,while the nutrient conversion rate was the measuring index of fertilizer efficiency in more seasons.It showed that the fertilizer utilization rate was significantly correlated,or the nutrient conversion rate was significantly correlated.
基金Collaborative Innovation Task of Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences—Integration and Demonstration of Green and Efficient Agricultural Technology Innovation in Danjiangkou Water Conservation Area(CAAS-XTCX2016015)Major Scientific and Technological Projects in Guangxi(GUIKE AA17204077)+2 种基金Special Project of Guangxi Science and Technology Base and Talent(GUIKE AD18126012)First-class Discipline(Geography)Construction Project in GuangxiSpecial Funds for"Guangxi Bagui Scholars".
文摘This paper studied the relationships between utilization ratios and conversion rates of nitrogen,phosphorus and potassium for maize by data mining method based on data of"3414 fertilizer field trials"of maize by published papers from national soil testing and recommendation since 2005.The results and conclusions were as follows:①the conceptual model of fertilizer utilization ratio of maize for plot was that,Y N≈a+b×optimum yield,Y P≈a+b×optimum yield-c×optimum nitrogen application amount-d×optimum potassium application amount,Y K≈a-b×optimum nitrogen application amount-c×temperature in growth season-d×rainfall in growth season,respectively.②Fertilizer utilization ratio and nutrient conversion rate had 4 kinds of relationships.No significant relationships:22,of which 16 were soil nutrients and 5 were environmental factors,the results showed that soil nutrients and environmental factors had little effect on nutrient conversion rate and fertilizer utilization ratio;consistent significant relationships:14,illustrating that conversion rate and utilization ratio of maize were consistent in most cases,and it was because that maize was planted for a long term,and its fertilizer absorption law was basically stable;contrary significant relationships:0,illustrating that there was no reverse relationship between conversion rate and utilization ratio of maize;complementary significant relationships:18,the cause of the complementary phenomenon was that the fertilizer utilization ratio was the measuring index of fertilizer efficiency in one season,while the nutrient conversion rate was the measuring index of fertilizer efficiency in more seasons.It showed that the fertilizer utilization ratio was significantly correlated,or the nutrient conversion rate was significantly correlated.
基金supported by the National Natural Science Foundation of China(51409066,51761135013)High Technology Ship Scientific Research Project from the Ministry of Industry and Information Technology of the People's Republic of China-Floating Security Platform Project(the second stage,201622)the Fundamental Research Fund for the Central University(HEUCFJ180104,HEUCFP1809)
文摘In this study, we investigated the hydrodynamic and energy conversion performance of a double-float wave energy converter(WEC) based on the linear theory of water waves. The generator power take-off(PTO) system is modeled as a combination of a linear viscous damping and a linear spring. Using the frequency domain method, the optimal damping coefficient of the generator PTO system is derived to achieve the optimal conversion efficiency(capture width ratio).Based on the potential flow theory and the higher-order boundary element method(HOBEM), we constructed a threedimensional model of double-float WEC to study its hydrodynamic performance and response in the time domain. Only the heave motion of the two-body system is considered and a virtual function is introduced to decouple the motions of the floats. The energy conversion character of the double-float WEC is also evaluated. The investigation is carried out over a wide range of incident wave frequency. By analyzing the effects of the incident wave frequency, we derive the PTO's damping coefficient for the double-float WEC's capture width ratio and the relationships between the capture width ratio and the natural frequencies of the lower and upper floats. In addition, it is capable to modify the natural frequencies of the two floats by changing the stiffness coefficients of the PTO and mooring systems. We found that the natural frequencies of the device can directly influence the peak frequency of the capture width, which may provide an important reference for the design of WECs.
基金supported by the National Basic Research Program of China(2013CB228104)
文摘In situ catalytic conversion of biomass fast pyrolysis vapors was carried out on HZSM-5 with varying Si/Al ratios(ranging from 20 to 300) at 450 °C. The effects of Si/Al ratios of HZSM-5 zeolites on the distribution of biomass fast pyrolysis products and carbon deposits on catalysts were investigated. It was quite remarkable that after in situ catalytic conversion the amount of light phenols and hydrocarbons increased significantly while that of heavy phenols decreased a lot. Besides, the yield of cyclopentenones with relatively low oxygen content generally increased. It also indicated that as the Si/Al ratios of HZSM-5 increased, the amount of hydrocarbons and light phenols was found to drop greatly. The amount of carbon deposits was found to be around 8.5% with the exception of HZSM-5 with the Si/Al ratio of 300,which is much lower. Moreover, the carbon deposits yield dropped gradually with increasing Si/Al ratios of HZSM-5.Calcination of spent catalysts at 600 °C helped to restore the catalytic activity to a large extent despite a relatively lower efficiency of deoxygenation. Results indicated that HZSM-5 with relatively high acidity displayed great catalytic performance.
基金financially supported by the National Natural Science Foundation of China(Grant No.51579055)the Natural Science Foundation of Jiangsu Province(Grant No.BK20180980)
文摘Point absorber wave energy device with multiple degrees of freedom(DOF) is assumed to have a better absorption ability of mechanical energy from ocean waves. In this paper, a coaxial symmetric articulated point absorber wave energy converter with two degrees of freedom is presented. The mechanical equations of the oscillation buoy with power take-off mechanism(PTO) in regular waves are established. The three-dimensional numerical wave tank is built in consideration of the buoy motion based upon the CFD method. The appropriate simulation elements are selected for the buoy and wave parameters. The feasibility of the CFD method is verified through the contrast between the numerical simulation results of typical wave conditions and test results. In such case, the buoy with single DOF of heave, pitch and their coupling motion considering free(no PTO damping) and damped oscillations in regular waves are simulated by using the verified CFD method respectively. The hydrodynamic and wave energy conversion characteristics with typical wave conditions are analyzed. The numerical results show that the heave and pitch can affect each other in the buoy coupling motion, hydrodynamic loads, wave energy absorption and flow field.The total capture width ratio with two coupled DOF motion is higher than that with a single DOF motion. The wave energy conversion of a certain DOF motion may be higher than that of the single certain DOF motion even though the wave is at the resonance period. When the wave periods are high enough, the interaction between the coupled DOF motions can be neglected.
基金Project supported by the National Natural Science Foundation of China (Grant No 60477023)the Natural Science Foundation of Science and Technology Commission of Liaoning Province, China (Grant No 20062137)
文摘The green and red up-conversion emissions centred at about 534, 549 and 663 nm of wavelength, corresponding respectively to the ^2H11/2 → ^4I15/2, ^4S3/2 → ^4I15/2 and ^4F9/2 → ^4I15/2 transitions of Er^3+ ions, have been observed for the Er^3+-doped silicate glass excited by a 978 nm semiconductor laser beam. Excitation power dependent behaviour of the up-conversion emission intensity indicates that a two-photon absorption up-conversion process is responsible for the green and red up-conversion emissions. The temperature dependence of the green up-conversion emissions is also studied in a temperature range of 296-673 K, which shows that Er^3+-doped silicate glass can be used as a sensor in high-temperature measurement.
文摘The studies for raising potash feldspar utilization ratio by physical, biological and chemical methods are carried out in laboratory and the results are presented. It is shown that calcinatory and biological methods have positive effects on conversion of K in potash feldspar into water-soluble form, but the conversion is low; chemical method can change most of insoluble potassium into available form, and might be significant in industry to some extent.
基金financially supported by the National Natural Science Foundation of China (Grant No.U2006226)。
文摘Experiments were conducted on risers with different mass ratios to study the effect of mode conversion and spanwise correlation. The slenderness ratio of the riser model was set as 169, and the Reynolds numbers are 1600-14400. The dynamic responses of riser models versus reduced velocity were analyzed, and the spanwise displacement, frequency,and trajectory of the mode conversion from the lower to the higher mode were explored. The results revealed that the riser model with a higher mass ratio excites a higher number of modes. The conversion region of multi-mode competition exists and narrows with the increasing mass ratio. Mode conversion is continuous and manifests as the transmission of peaks and troughs in mode shape: the peaks and troughs of mode shape move up in the mode stable development region and move down in the mode conversion region. The single-mode dominating vibration exhibits a standing wave feature, and the traveling wave feature is significant in the mode conversion region. Furthermore, the frequency jump is always transmitted from the trough to the peak of the mode shape, and finally, all the axial positions vibrate at the same frequency. The trajectory in the mode conversion region deviates from the 8-shape and recovers the standard8-shape at the middle and late stages of the mode stable development region.
文摘The effect of fishmeal quality on growth,feed conversion ratio and protein digestibility was studied in a growth experiment with shrimp and red seabream.The shrimp and fish were fed three diets varing in the quality of the fishmeal used in the respective feeds: low quality fish meal,good quality fish meal,and Peru fish meal.The experiment lasted for 2 months.The shrimp and fish fed the feed with good quality fish meal showed significantly better feed conversion ratio,weight gain rate,protein digestibility than the other groups.