在水肥一体化控制过程中,水肥浓度变化呈现非线性、滞后性的特点,传统的浓度调节方式存在控制精度低、响应速度较慢等问题,难以满足新疆南疆地区设施农业黄沙基质栽培模式下的水肥施用需求。本研究针对该现象设计了一种参数自整定的模糊...在水肥一体化控制过程中,水肥浓度变化呈现非线性、滞后性的特点,传统的浓度调节方式存在控制精度低、响应速度较慢等问题,难以满足新疆南疆地区设施农业黄沙基质栽培模式下的水肥施用需求。本研究针对该现象设计了一种参数自整定的模糊PID控制策略,根据输入误差和误差变化率,结合模糊规则,输出Δkp、Δki、Δkd 3个整定参数,实现了对传统PID控制参数的实时调节。结果表明与传统PID控制策略相比,在母液电导率为7.2 mS cm的条件下,模糊PID在控制水肥电导率达到设定值时超调量减少了46.40%,稳态时间提前了39.05 s,具有良好鲁棒性、稳态性和响应特性,能够满足黄沙基质栽培模式下的精准水肥施用需求。展开更多
Nowadays, tourism has become an increasingly significant driving force of modern urbanization in China. However, it has caused varieties of problems, such as resource unreasonable utilization, society unfair play, and...Nowadays, tourism has become an increasingly significant driving force of modern urbanization in China. However, it has caused varieties of problems, such as resource unreasonable utilization, society unfair play, and environment pollution, etc. Thus, the establishment of an efficient and sustainable space partition model for tourism urbanization, from the geographical perspective, is highly necessary and urgent. Herein, a new evaluation model of tourist town space, referred to as Tourism Sectorization Opportunity Spectrum(TSOS), is established on the relationships between productionliving-ecology spaces. TSOS is a kind of quantitative evaluation model involving such factors as urban living area, ecological conservation area and the tourism industry. Furthermore, the analysis of quantitative production-living-ecology spatial overlap has been utilized for space division in a tourism urbanization area. This paper, using both the TSOS model and GIS technology, analyzes the spatial restructure of the Mayangxi ecotourism area. Theresult demonstrates that tourism industrial space takes the Shanchong Village as a core which shows a pattern of local regional agglomeration and a fuzzy edge extending along the entire Mayangxi River. The urban living area should be consolidated in the Shili village with the supporting facilities and living space for tourism. In addition, Tianzhu Mountain forest park should be the key environmental protection area. The case study on the Mayangxi ecotourism area verifies that the TSOS model has strong operability. Therefore, TSOS model provides a scientific foundation for the space reconstruction of new urbanization area, and an effective tool for optimizing the space partition of a tourism urbanization area.展开更多
OBJECTIVE Ketamine is an injectable anesthetic and recreational drug of abuse commonly used worldwide. Many experimental studies have shown that ketamine can impair cognitive function and induce psychotic states. Neur...OBJECTIVE Ketamine is an injectable anesthetic and recreational drug of abuse commonly used worldwide. Many experimental studies have shown that ketamine can impair cognitive function and induce psychotic states. Neuroinflammation has been suggested to play an important role in neurodegeneration. Meanwhile,ketamine has been showed to modulate the levels of inflammatory cytokines.Therefore,we sought to investigate whether the effects of ketamine on the central nervous system is associated with the inflammatory cytokines. METHODS We established acute(single or multiple intraperitoneal injection) and chronic(six months daily intraperitoneal injection) ketamine administration models in C57BL/6 mice,evaluated the spatial recognition memory and emotional response by applying the Y maze test and open field test. We analyzed the changes of inflammatory cytokines interleukin-6(IL-6),interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) levels in mouse hippocampus,employing Western blot,quantitative reverse transcriptase-polymerase chain reaction(qR T-PCR) and immunohistochemistry. RESULTS Ketamine induced spatial recognition memory deficit,reduced anxiety-like behaviors in mice after chronic administration,and it was dose-dependent. Moreover,we found that ketamine could increase the levels of mouse hippocampal inflammatory cytokines IL-6 and IL-1β after single,multiple and long-term administration in a dose-dependent manner. However,the level of TNF-α expressed differently in mouse hippocampus under different conditions. Single administration of ketamine increased the level of TNF-α,whereas multiple and long-term administration decreased it significantly. We considered that TNF-α might exist bi-directional regulatory pathway,which was associated with the dose and duration of ketamine administration. CONCLUSION Our results suggest that the alterations of inflammatory cytokines IL-6,IL-1β and TNF-α levels may be involved in the neurotoxicity of ketamine.展开更多
文摘在水肥一体化控制过程中,水肥浓度变化呈现非线性、滞后性的特点,传统的浓度调节方式存在控制精度低、响应速度较慢等问题,难以满足新疆南疆地区设施农业黄沙基质栽培模式下的水肥施用需求。本研究针对该现象设计了一种参数自整定的模糊PID控制策略,根据输入误差和误差变化率,结合模糊规则,输出Δkp、Δki、Δkd 3个整定参数,实现了对传统PID控制参数的实时调节。结果表明与传统PID控制策略相比,在母液电导率为7.2 mS cm的条件下,模糊PID在控制水肥电导率达到设定值时超调量减少了46.40%,稳态时间提前了39.05 s,具有良好鲁棒性、稳态性和响应特性,能够满足黄沙基质栽培模式下的精准水肥施用需求。
基金supported and funded by the National Natural Science Foundation of China(Grant No.41071110)the State Ethnic Affairs Youth Foundation of China(Grant No.2015-GM073)
文摘Nowadays, tourism has become an increasingly significant driving force of modern urbanization in China. However, it has caused varieties of problems, such as resource unreasonable utilization, society unfair play, and environment pollution, etc. Thus, the establishment of an efficient and sustainable space partition model for tourism urbanization, from the geographical perspective, is highly necessary and urgent. Herein, a new evaluation model of tourist town space, referred to as Tourism Sectorization Opportunity Spectrum(TSOS), is established on the relationships between productionliving-ecology spaces. TSOS is a kind of quantitative evaluation model involving such factors as urban living area, ecological conservation area and the tourism industry. Furthermore, the analysis of quantitative production-living-ecology spatial overlap has been utilized for space division in a tourism urbanization area. This paper, using both the TSOS model and GIS technology, analyzes the spatial restructure of the Mayangxi ecotourism area. Theresult demonstrates that tourism industrial space takes the Shanchong Village as a core which shows a pattern of local regional agglomeration and a fuzzy edge extending along the entire Mayangxi River. The urban living area should be consolidated in the Shili village with the supporting facilities and living space for tourism. In addition, Tianzhu Mountain forest park should be the key environmental protection area. The case study on the Mayangxi ecotourism area verifies that the TSOS model has strong operability. Therefore, TSOS model provides a scientific foundation for the space reconstruction of new urbanization area, and an effective tool for optimizing the space partition of a tourism urbanization area.
文摘OBJECTIVE Ketamine is an injectable anesthetic and recreational drug of abuse commonly used worldwide. Many experimental studies have shown that ketamine can impair cognitive function and induce psychotic states. Neuroinflammation has been suggested to play an important role in neurodegeneration. Meanwhile,ketamine has been showed to modulate the levels of inflammatory cytokines.Therefore,we sought to investigate whether the effects of ketamine on the central nervous system is associated with the inflammatory cytokines. METHODS We established acute(single or multiple intraperitoneal injection) and chronic(six months daily intraperitoneal injection) ketamine administration models in C57BL/6 mice,evaluated the spatial recognition memory and emotional response by applying the Y maze test and open field test. We analyzed the changes of inflammatory cytokines interleukin-6(IL-6),interleukin-1β(IL-1β) and tumor necrosis factor-α(TNF-α) levels in mouse hippocampus,employing Western blot,quantitative reverse transcriptase-polymerase chain reaction(qR T-PCR) and immunohistochemistry. RESULTS Ketamine induced spatial recognition memory deficit,reduced anxiety-like behaviors in mice after chronic administration,and it was dose-dependent. Moreover,we found that ketamine could increase the levels of mouse hippocampal inflammatory cytokines IL-6 and IL-1β after single,multiple and long-term administration in a dose-dependent manner. However,the level of TNF-α expressed differently in mouse hippocampus under different conditions. Single administration of ketamine increased the level of TNF-α,whereas multiple and long-term administration decreased it significantly. We considered that TNF-α might exist bi-directional regulatory pathway,which was associated with the dose and duration of ketamine administration. CONCLUSION Our results suggest that the alterations of inflammatory cytokines IL-6,IL-1β and TNF-α levels may be involved in the neurotoxicity of ketamine.
