To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehol...To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehole.Combining with the engineering geological conditions,we built a numeral model to study the influence rule of the aquifer hydraulic pressure and seepage location of feeding borehole on the amount of seepage with fnite element numerical method.The results show that the nonlinear relationship is presented among the amount of seepage,the seepage location and aquifer hydraulic pressure.The higher the aquifer hydraulic pressure is,the closer the distance between seepage location and aquifer is,and the faster the harmful levels of aquifer will grow.In practice,we calculated the allowable seepage of feeding borehole by the optimum moisture content and natural moisture content of backflling materials,and then determined the protection zone of feeding borehole,so the moisture content of backflling materials can be controlled within the scope of optimum moisture content.展开更多
Load of an automatic feed mechanism is composed of the stretching force of feed belt at the entrance to lower flexible guidance and the friction force between feed belt and flexible guidance. A mathematical model for ...Load of an automatic feed mechanism is composed of the stretching force of feed belt at the entrance to lower flexible guidance and the friction force between feed belt and flexible guidance. A mathematical model for computing the load was presented. An optimization problem was formulated to determine the attitude of the flexible guidance based on the principle that the potential energy stored in the system was the minimum at the equilibrium. Then the friction force was obtained according to the attitude of guide leaves and the moving velocity of the feed belt and the friction factor. Consequently, the load of the automatic feed mechanism can be calculated. Finally, an example was given to compute the load when the horizontal and elevating firing angles of the automation were respectively 45° and 30°. The computing result can be a criterion to determine the designing parameters of automat.展开更多
The welding wire feed mechanism is an important component of welding equipment, both reliability and stabilization are the premise that the welding quality can be ensured. The PID is currently adapted to control the w...The welding wire feed mechanism is an important component of welding equipment, both reliability and stabilization are the premise that the welding quality can be ensured. The PID is currently adapted to control the welding wire feed mechanism, although the fuzzy PID has advantage of fast response and adaptation, the precision of fuzzy PID is lower. Accordingly, the fuzzy self-adaptive PID controller was proposed through changing fuzzy input variables and output variables based on variable universe, simple furwtion is adopted as scaling factor, the fuzzy PID controller parameters are adjusted to improve the precision and adjustment range. Simulation results show that control effects of fuzzy self-adaptive PID adopted by the welding wire feed mechanism have good adaptive ability and robustness based on variable universe, the welding experiments indicate that the welding quality met the requirements actually.展开更多
In the development of family enterprises of feed and veterinary drugs in China,there are many problems,such as lack of organic integration of human capital and social human capital.This paper introduced development th...In the development of family enterprises of feed and veterinary drugs in China,there are many problems,such as lack of organic integration of human capital and social human capital.This paper introduced development thread of family enterprises of feed and veterinary drugs in China,analyzed theories and practical development requirement for improving professional manager mechanism,and came up with recommendations including establishing proper employing system,incentive and restraint mechanism,corporate culture,and professional manager market.展开更多
Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical ...Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical properties has yet to be explored.In this study,we report on the fabrication of intrinsically super-strong fluorescent silk by feeding Bombyx mori silkworm carbon nanodots(CNDs).The CNDs were incorporated into silk fibroin,hindering the conformation transformation,confining crystallization,and inducing orientation of mesophase.The resultant silk exhibited super-strong mechanical properties with breaking strength of 521.9±82.7 MPa and breaking elongation of 19.2±4.3%,improvements of 55.1%and 53.6%,respectively,in comparison with regular silk.The CNDs-reinforced silk displayed intrinsic blue fluorescence when exposed to 405 nm laser and exhibited no cytotoxic effect on cells,suggesting that multi-functional silks would be potentially useful in bioimaging and other applications.展开更多
Purpose of review: This article reviews the thoracic complications from malpositioned blindly inserted nasogastric feeding tubes in mechanically ventilated patients in intensive care and the methods to check the posit...Purpose of review: This article reviews the thoracic complications from malpositioned blindly inserted nasogastric feeding tubes in mechanically ventilated patients in intensive care and the methods to check the position and promote safe placement of the feeding tubes. Recent findings: Malpositioned feeding tubes are not included in risk management databases. The reported incidence is 1-3% and more than half occur in mechanically ventilated patients. Eighty three mechanically ventilated patients were reported with malpositioned nasogastric tubes and 66% of them developed serious thoracic complications. Pneumothoraces accounted for 80% of thoracic complications that were evenly distributed between tubes with and without stylet. Repeated misplacements appear to increase the risk. Non-radiological confirmation of the position of the tube has suboptimal performance. Protocols to place feeding tubes and new technology are promising candidates. Summary: Malpositioned nasogastric feeding tubes are underreported and associated with serious thoracic complications in mechanically ventilated patients. We need more data to answer whether we can afford to prevent them.展开更多
This article was to study the potential resistance mechanism of three different wheat varieties (Ww2730, Xiaoyan 22 and Batis) in the seedling stage to Sitobion avenae. The aphid feeding behavior was ascertained by ...This article was to study the potential resistance mechanism of three different wheat varieties (Ww2730, Xiaoyan 22 and Batis) in the seedling stage to Sitobion avenae. The aphid feeding behavior was ascertained by stylet penetration activities monitoring using the electrical penetration graph (EPG) technique. When the aphids feed on Ww2730 seedlings, the time for the 1st duration probing was later than that on Xiaoyan 22 and Batis significantly, and the number of interrupted probing before the 1st duration probing was more than that on Xiaoyan 22 and Batis significantly, and the 1st duration probing was shorter than that on Xiaoyan 22 and Batis significantly. The durations of the stylet pierce from the extra- to the intra-cellular (pd Ⅱ-1) on Ww2730 and Xiaoyan 22 were longer than those on Batis significantly. The duration of the potential drop (pd) in C wave on Ww2730 was longer than that on Xiaoyan 22 and Batis significantly. The times and duration of the G wave (ingestion in xylem) on Ww2730 were more and longer than those on Xiaoyan 22 and Batis significantly. The times of spot G wave on Batis was more than that on Ww2730 significantly, but the duration of spot G was shorter than that on Xiaoyan 22 and Ww2730 significantly. The total time of E1 wave, the longest duration of E1 fractions, and the mean duration time of E1 fractions that followed E2 wave on Xiaoyan 22 and Batis were all significantly longer than those on Ww2730. There was no difference of the mean duration of the 1st E1 wave on the 3 varieties, but the mean durations of other E1 wave on Ww2730 and Xiaoyan 22 were shorter than those on Batis significantly. The other wave parameters, including times and durations of F and E2 were all not different on the 3 wheat varieties. It is suggested that the resistance mechanism of wheat variety Ww2730 to S. avenae is a restriction factor of feeding in epidermis, the thicker cell wall in mesophyll, and secondary metabolites or nutrition unbalance in phloem in the seedling phase. The resistance mechanism of Xiaoyan 22 is thicker cell wall and more cell layer in mesophyll in the seedling phase. The feeding strategy of S. avenae against the resistance of Ww2730 was to shorten the second duration of secrete watery salivation to xylem than the first.展开更多
The automatic forming device of the cladding layer of the solid rocket engine is a kind of equipment that can automatically complete the coating process of the coating layer.It is mainly composed of the feeding system...The automatic forming device of the cladding layer of the solid rocket engine is a kind of equipment that can automatically complete the coating process of the coating layer.It is mainly composed of the feeding system,the detection system and the automatic control system.The feeding system plays the role of providing the slurry in the coating process.In order to ensure the uniformity and stability of the feeding device,the automatic forming and feeding system of the coating is studied in this paper.The dynamic analysis of the slurry transportation process in the automatic coating system is carried out.In this paper,the feed cylinder is designed in theory.The feeding mode of the servo electric cylinder is adopted.Through the analysis of the hydrodynamic equations,the mixture model is chosen as the basis for the numerical simulation analysis.We use the SolidWorks software to create the geometric model of the feed cylinder.The dynamic analysis of the feed cylinder is carried out by Fluent software,and the convergent residual diagram and the fluid cloud chart are obtained.Fluent software is used for simulation analysis.The simulation results show that the distribution device has stable flow velocity and uniform slurry flow in the feeding process.The effect of scraping and coating process can be guaranteed by the feeding device,which provides a theoretical basis for actual production.展开更多
With the background of the control of additional mechanical force droplet transfer in MIG/MAG welding, regarding the AC servo motor as core, a novel oscillating wire feeding system has been developed with excellent pe...With the background of the control of additional mechanical force droplet transfer in MIG/MAG welding, regarding the AC servo motor as core, a novel oscillating wire feeding system has been developed with excellent performances of control and dynamic acceleration which is tested. System constitution and operation principle are introduced in this paper. Influences of parameters on dynamic acceleration performance are analyzed and discussed emphatically, such as oscillating frequency, oscillating amplitude and draw-back speed. Experimental result indicates that according to the technique of welding control, the novel wire feeding system responds rapidly to various kinds of control orders of wire feeding and draw-back, and realizes flexible control of welding wire axial movement, including dynamic shifting,oscillating and so on.展开更多
Background: The optimal rate of feeding advancement after initiation of early enteral nutrition (EEN) for underweight, critically ill patients is unknown. Methods: We conducted a retrospective chart review in intensiv...Background: The optimal rate of feeding advancement after initiation of early enteral nutrition (EEN) for underweight, critically ill patients is unknown. Methods: We conducted a retrospective chart review in intensive care unit (ICU) patients with a body mass index (BMI) < 20.0 kg/m<sup>2</sup>. Patients were categorized into Group R, which reached the energy target within 3 days of EEN initiation, and Group S, which reached the energy target 4 or more days after EEN initiation. Results: A total of 65 patients with a median age of 73 years were included in the study. No significant differences were observed between the two groups for all-cause mortality, ICU-free days, or length of hospital stay. Ventilator-free days (VFDs) were significantly fewer in Group R than in Group S (18.0 [0.0 - 22.0] vs. 21.0 [16.3 - 24.8] days;P = 0.046). A significantly higher number of patients requiring mechanical ventilation (MV) at hospital discharge were observed in Group R than in Group S (29% vs. 8%;P = 0.030). Multivariable analyses with adjustment for confounders found that days required to reach target energy intake after EEN initiation were significantly and independently associated with the requirement for MV at hospital discharge, but not with VFDs. Conclusion: A slow rate of feeding advancement after initiation of EEN in critically ill patients having a BMI of <20.0 kg/m<sup>2</sup> might be associated with a reduced requirement for MV at hospital discharge. These results require confirmation in a large multicenter trial of underweight, critically ill patients.展开更多
The discovery and application of antibiotics in animal feeds have boomed the development of intensive animal husbandry in the last century,until the emergence of antibiotics-resistant bacteria.To alleviate the risks a...The discovery and application of antibiotics in animal feeds have boomed the development of intensive animal husbandry in the last century,until the emergence of antibiotics-resistant bacteria.To alleviate the risks aroused by antibiotics-resistant bacteria,effective antibiotic substitutes are urgently needed to replace antibiotics.Essential oils(EOs)derived from plants are illustrated as the promising antibiotic substitutes used in animal feeds,as same as their current views for poultry and livestock industries in the future.It has been widely demonstrated that the phytochemicals in EOs show multiple biofunctionability and are less likely to induce resistance in bacteria.The beneficial effects of EOs feed supplementation on the intestinal inflammation,intestinal flora,immunity,digestion,and growth performances have been already extensively examined.However,the cost-effectiveness,odor,volatility,instability and bioavailability are the challenges in effectively utilizing EOs in animal intestines.Based on previous researches,and these challenges can partially be resolved by microencapsulation and nanotechnology are promising techniques to deal with these challenges.This article presents the feasibility and foundation of EOs application as antibiotic substitutes in animal feeds,and illustrates the mechanisms,functional performances and superiority of EOs compared with antibiotics.展开更多
基金funded by the State Key Development Program for Basic Research of China(No.2013CB227900)the National High Technology Joint Research Program of China(No.2012BAB13B00)
文摘To solve the problem of water seepage of vertical feeding borehole for solid materials,we established the fluid-solid coupling dynamic model of groundwater flowing in rock mass adjacent to the vertical feeding borehole.Combining with the engineering geological conditions,we built a numeral model to study the influence rule of the aquifer hydraulic pressure and seepage location of feeding borehole on the amount of seepage with fnite element numerical method.The results show that the nonlinear relationship is presented among the amount of seepage,the seepage location and aquifer hydraulic pressure.The higher the aquifer hydraulic pressure is,the closer the distance between seepage location and aquifer is,and the faster the harmful levels of aquifer will grow.In practice,we calculated the allowable seepage of feeding borehole by the optimum moisture content and natural moisture content of backflling materials,and then determined the protection zone of feeding borehole,so the moisture content of backflling materials can be controlled within the scope of optimum moisture content.
基金Project supported by the Seventh Research Institute of China State Shipbuilding Corporation
文摘Load of an automatic feed mechanism is composed of the stretching force of feed belt at the entrance to lower flexible guidance and the friction force between feed belt and flexible guidance. A mathematical model for computing the load was presented. An optimization problem was formulated to determine the attitude of the flexible guidance based on the principle that the potential energy stored in the system was the minimum at the equilibrium. Then the friction force was obtained according to the attitude of guide leaves and the moving velocity of the feed belt and the friction factor. Consequently, the load of the automatic feed mechanism can be calculated. Finally, an example was given to compute the load when the horizontal and elevating firing angles of the automation were respectively 45° and 30°. The computing result can be a criterion to determine the designing parameters of automat.
文摘The welding wire feed mechanism is an important component of welding equipment, both reliability and stabilization are the premise that the welding quality can be ensured. The PID is currently adapted to control the welding wire feed mechanism, although the fuzzy PID has advantage of fast response and adaptation, the precision of fuzzy PID is lower. Accordingly, the fuzzy self-adaptive PID controller was proposed through changing fuzzy input variables and output variables based on variable universe, simple furwtion is adopted as scaling factor, the fuzzy PID controller parameters are adjusted to improve the precision and adjustment range. Simulation results show that control effects of fuzzy self-adaptive PID adopted by the welding wire feed mechanism have good adaptive ability and robustness based on variable universe, the welding experiments indicate that the welding quality met the requirements actually.
基金Supported by Project of Business Management Cultivation Discipline in Department of Business and Trade,Rongchang Campus,Southwest University(RCQG207001)
文摘In the development of family enterprises of feed and veterinary drugs in China,there are many problems,such as lack of organic integration of human capital and social human capital.This paper introduced development thread of family enterprises of feed and veterinary drugs in China,analyzed theories and practical development requirement for improving professional manager mechanism,and came up with recommendations including establishing proper employing system,incentive and restraint mechanism,corporate culture,and professional manager market.
基金sponsored by the National Key Research and Development Program of China(2016YFA0201700,2016YFA0201702)the Fundamental Research Funds for the Central Universities(2232019A3-06,2232019D3-02)+2 种基金the National Key Research and Development Program of China(2018YFC1105800)the National Natural Science Foundation of China(21674018,51903045)the Shanghai Belt and Road Joint Laboratory of Advanced Fiber and Low-Dimension Materials(18520750400).
文摘Fluorescent silk is fundamentally important for the development of future tissue engineering scaffolds.Despite great progress in the preparation of a variety of colored silks,fluorescent silk with enhanced mechanical properties has yet to be explored.In this study,we report on the fabrication of intrinsically super-strong fluorescent silk by feeding Bombyx mori silkworm carbon nanodots(CNDs).The CNDs were incorporated into silk fibroin,hindering the conformation transformation,confining crystallization,and inducing orientation of mesophase.The resultant silk exhibited super-strong mechanical properties with breaking strength of 521.9±82.7 MPa and breaking elongation of 19.2±4.3%,improvements of 55.1%and 53.6%,respectively,in comparison with regular silk.The CNDs-reinforced silk displayed intrinsic blue fluorescence when exposed to 405 nm laser and exhibited no cytotoxic effect on cells,suggesting that multi-functional silks would be potentially useful in bioimaging and other applications.
文摘Purpose of review: This article reviews the thoracic complications from malpositioned blindly inserted nasogastric feeding tubes in mechanically ventilated patients in intensive care and the methods to check the position and promote safe placement of the feeding tubes. Recent findings: Malpositioned feeding tubes are not included in risk management databases. The reported incidence is 1-3% and more than half occur in mechanically ventilated patients. Eighty three mechanically ventilated patients were reported with malpositioned nasogastric tubes and 66% of them developed serious thoracic complications. Pneumothoraces accounted for 80% of thoracic complications that were evenly distributed between tubes with and without stylet. Repeated misplacements appear to increase the risk. Non-radiological confirmation of the position of the tube has suboptimal performance. Protocols to place feeding tubes and new technology are promising candidates. Summary: Malpositioned nasogastric feeding tubes are underreported and associated with serious thoracic complications in mechanically ventilated patients. We need more data to answer whether we can afford to prevent them.
基金This study was supported financially by the Cooperation Project Foundation between the Ministries of Agriculture of Germany and China(02/03)National Natural Science Foundation of China(39970112)Youth Foundation of Northwest A&F University(080807,08080252).
文摘This article was to study the potential resistance mechanism of three different wheat varieties (Ww2730, Xiaoyan 22 and Batis) in the seedling stage to Sitobion avenae. The aphid feeding behavior was ascertained by stylet penetration activities monitoring using the electrical penetration graph (EPG) technique. When the aphids feed on Ww2730 seedlings, the time for the 1st duration probing was later than that on Xiaoyan 22 and Batis significantly, and the number of interrupted probing before the 1st duration probing was more than that on Xiaoyan 22 and Batis significantly, and the 1st duration probing was shorter than that on Xiaoyan 22 and Batis significantly. The durations of the stylet pierce from the extra- to the intra-cellular (pd Ⅱ-1) on Ww2730 and Xiaoyan 22 were longer than those on Batis significantly. The duration of the potential drop (pd) in C wave on Ww2730 was longer than that on Xiaoyan 22 and Batis significantly. The times and duration of the G wave (ingestion in xylem) on Ww2730 were more and longer than those on Xiaoyan 22 and Batis significantly. The times of spot G wave on Batis was more than that on Ww2730 significantly, but the duration of spot G was shorter than that on Xiaoyan 22 and Ww2730 significantly. The total time of E1 wave, the longest duration of E1 fractions, and the mean duration time of E1 fractions that followed E2 wave on Xiaoyan 22 and Batis were all significantly longer than those on Ww2730. There was no difference of the mean duration of the 1st E1 wave on the 3 varieties, but the mean durations of other E1 wave on Ww2730 and Xiaoyan 22 were shorter than those on Batis significantly. The other wave parameters, including times and durations of F and E2 were all not different on the 3 wheat varieties. It is suggested that the resistance mechanism of wheat variety Ww2730 to S. avenae is a restriction factor of feeding in epidermis, the thicker cell wall in mesophyll, and secondary metabolites or nutrition unbalance in phloem in the seedling phase. The resistance mechanism of Xiaoyan 22 is thicker cell wall and more cell layer in mesophyll in the seedling phase. The feeding strategy of S. avenae against the resistance of Ww2730 was to shorten the second duration of secrete watery salivation to xylem than the first.
基金Research Projects of Science Foundation of Institutions of Higher Learning in Inner Mongolia Autonomous Region,China(No.NJZY13117)
文摘The automatic forming device of the cladding layer of the solid rocket engine is a kind of equipment that can automatically complete the coating process of the coating layer.It is mainly composed of the feeding system,the detection system and the automatic control system.The feeding system plays the role of providing the slurry in the coating process.In order to ensure the uniformity and stability of the feeding device,the automatic forming and feeding system of the coating is studied in this paper.The dynamic analysis of the slurry transportation process in the automatic coating system is carried out.In this paper,the feed cylinder is designed in theory.The feeding mode of the servo electric cylinder is adopted.Through the analysis of the hydrodynamic equations,the mixture model is chosen as the basis for the numerical simulation analysis.We use the SolidWorks software to create the geometric model of the feed cylinder.The dynamic analysis of the feed cylinder is carried out by Fluent software,and the convergent residual diagram and the fluid cloud chart are obtained.Fluent software is used for simulation analysis.The simulation results show that the distribution device has stable flow velocity and uniform slurry flow in the feeding process.The effect of scraping and coating process can be guaranteed by the feeding device,which provides a theoretical basis for actual production.
基金NationalNatureScienceFoundation (No .5 9775 0 62 )
文摘With the background of the control of additional mechanical force droplet transfer in MIG/MAG welding, regarding the AC servo motor as core, a novel oscillating wire feeding system has been developed with excellent performances of control and dynamic acceleration which is tested. System constitution and operation principle are introduced in this paper. Influences of parameters on dynamic acceleration performance are analyzed and discussed emphatically, such as oscillating frequency, oscillating amplitude and draw-back speed. Experimental result indicates that according to the technique of welding control, the novel wire feeding system responds rapidly to various kinds of control orders of wire feeding and draw-back, and realizes flexible control of welding wire axial movement, including dynamic shifting,oscillating and so on.
文摘Background: The optimal rate of feeding advancement after initiation of early enteral nutrition (EEN) for underweight, critically ill patients is unknown. Methods: We conducted a retrospective chart review in intensive care unit (ICU) patients with a body mass index (BMI) < 20.0 kg/m<sup>2</sup>. Patients were categorized into Group R, which reached the energy target within 3 days of EEN initiation, and Group S, which reached the energy target 4 or more days after EEN initiation. Results: A total of 65 patients with a median age of 73 years were included in the study. No significant differences were observed between the two groups for all-cause mortality, ICU-free days, or length of hospital stay. Ventilator-free days (VFDs) were significantly fewer in Group R than in Group S (18.0 [0.0 - 22.0] vs. 21.0 [16.3 - 24.8] days;P = 0.046). A significantly higher number of patients requiring mechanical ventilation (MV) at hospital discharge were observed in Group R than in Group S (29% vs. 8%;P = 0.030). Multivariable analyses with adjustment for confounders found that days required to reach target energy intake after EEN initiation were significantly and independently associated with the requirement for MV at hospital discharge, but not with VFDs. Conclusion: A slow rate of feeding advancement after initiation of EEN in critically ill patients having a BMI of <20.0 kg/m<sup>2</sup> might be associated with a reduced requirement for MV at hospital discharge. These results require confirmation in a large multicenter trial of underweight, critically ill patients.
基金Financial support was provided by State Key Laboratory of Utilization of Woody Oil Resource(Grant no.2019XK2002)National Natural Science Foundation of China(Grant no.32202004,31972172)+2 种基金Natural Science Foundation of Jiangsu Province(Grant no.BK20201417)Jiangsu Province Research Fund(Grant no.JNHB-131)Starting Research Fund of Yantai University(Grant No.2222006)。
文摘The discovery and application of antibiotics in animal feeds have boomed the development of intensive animal husbandry in the last century,until the emergence of antibiotics-resistant bacteria.To alleviate the risks aroused by antibiotics-resistant bacteria,effective antibiotic substitutes are urgently needed to replace antibiotics.Essential oils(EOs)derived from plants are illustrated as the promising antibiotic substitutes used in animal feeds,as same as their current views for poultry and livestock industries in the future.It has been widely demonstrated that the phytochemicals in EOs show multiple biofunctionability and are less likely to induce resistance in bacteria.The beneficial effects of EOs feed supplementation on the intestinal inflammation,intestinal flora,immunity,digestion,and growth performances have been already extensively examined.However,the cost-effectiveness,odor,volatility,instability and bioavailability are the challenges in effectively utilizing EOs in animal intestines.Based on previous researches,and these challenges can partially be resolved by microencapsulation and nanotechnology are promising techniques to deal with these challenges.This article presents the feasibility and foundation of EOs application as antibiotic substitutes in animal feeds,and illustrates the mechanisms,functional performances and superiority of EOs compared with antibiotics.