长三角城市群旅游生态效率时空演化特征及其影响因素研究

长三角一体化是我国当前重要的国家战略之一,旅游业发展在助推长三角产业高质量一体化发展中扮演着重要角色。综合运用SBM-undesirable模型、核密度估计、空间分析等方法探索长三角城市群26个核心城市2007—2017年旅游生态效率时空演化特征,并运用面板Tobit回归模型探讨其影响因素。结果表明:(1)长三角城市群内旅游生态效率存在着显著不均衡性,研究期内旅游生态高效率城市有所减少,较高效率城市数量增加,低旅游生态效率城市增多且呈现向城市群西部敛缩的态势。(2)长三角城市群内旅游生态效率两级分化程度和地区之间的非均衡性在逐步减小。(3)长三角城市群旅游生态效率东部大于西部,北部大于南部,东西方向上非均衡性比南北方向更加显著。(4)长三角城市群旅游生态效率表现为以空间负相关为主的分布特征,空间异质性大于空间集聚性。(5)旅游经济规模、旅游产业结构、科技创新水平、城镇化发展、经济发展水平、建成区绿化覆盖率和对外开放水平对城市群整体和不同省市旅游生态效率影响的空间异质性较强。     

How does anti-corruption affect enterprise green innovation in China’s energy-intensive industries?

Environmental Geochemistry and Health - Rampant corruption exists in China’s energy-intensive industries. However, we know little about the nexus of corruption and enterprise green innovation...     

Predicting future invasion risk of three widespread malignant weeds on Qinghai-Tibet Plateau,using multi-algorithm ensemble models北大核心CSCD

农田恶性杂草相比普通杂草的传播更为迅速且难以有效防治,对农业生产危害严重.明确典型恶性杂草当前潜在分布面积及未来气候变化下对耕地的潜在入侵风险对农业生产管理具有重要意义.以广泛分布于青藏高原农田中的3种常见恶性杂草,即野燕麦(Avena fatua L.)、一年生早熟禾(Poa annua L.)和狗尾草[Setaria viridis(L.)P.Beauv.]为研究对象,利用广义增强模型(GBM)、广义线性模型(GLM)、人工神经网络(ANN)、最大熵(MaxEnt)、随机森林(RF)及多元自适应回归样条(MARS)算法集合预测上述3种杂草在青藏高原的潜在地理分布以及驱动其变化的关键因子,以评估其对耕地的入侵风险.未来气候场景采用最新的第六次国际耦合模式比较计划(CMIP6)框架下2050年的4种共享经济路线(SSP1-2.6、2-4.5、3-7.0、5-8.5).结果显示:野燕麦适宜分布区面积约为3.5912×10^(5) km^(2),主要分布于四川西南部及青海东部,零星分布于甘肃、西藏和新疆;一年生早熟禾和狗尾草的适宜分布区面积约为4.3046×10^(5) km^(2)和2.0036×10^(5) km^(2),均主要分布于四川西南部和西藏东南部,零星分布于青海东部和甘肃南部.年均温是3种杂草分布的最主要驱动因子.此外,人类足迹和土壤有效氮是影响野燕麦分布的相对重要因子;土壤酸碱度、最暖季降水量是影响一年生早熟禾分布的重要因子;温度季节性、最暖季降水量是影响狗尾草分布的重要因子.预计至2050年,3种杂草在4种情境下均会出现不同程度的扩张,狗尾草的扩张面积表现出随辐射强迫的增强呈先升高后趋于稳定的趋势,而另两种杂草则呈先升后降的趋势.预计3种杂草的潜在分布面积在耕地中的占比与扩张面积的变化趋势一致,且在主产区的占比高于非主产区.模拟结果表明,未来气候变化下,随着3种恶性杂草的适宜分布区面积的扩张,其对青藏高原耕地的入侵风险将增加,尤其是粮食主产区所面临威胁更为严峻,建议应重点关注青藏高原粮食主产区恶性杂草的生理生态、迁移扩散和防治技术研究.(图6表2参61)     

Environmental risks and the potential benefits of nanopesticides: a review

Environmental Chemistry Letters - With the escalating food demand of the ever-increasing global population and the rapid development of nanotechnology, nanopesticides are being proposed as...     

Four kinds of capping materials for controlling phosphorus and nitrogen release from contaminated sediment using a static simulation experiment

• Lanthanum modified bentonite (LMB) can effectively absorb phosphorus (P). • Water treatment plant sludge (WTPS) capping is effective for controlling P release. •Aluminum-based P-inactivation agent (Al-PIA) is an efficient P control material. •The P adsorbed by WTPS and Al-PIA is mainly in the form of NAIP. We determined the effects of quartz sand (QS), water treatment plant sludge (WTPS), aluminum-based P-inactivation agent (Al-PIA), and lanthanum-modified bentonite (LMB) thin-layer capping on controlling phosphorus and nitrogen release from the sediment, using a static simulation experiment. The sediment in the experiment was sampled from Yundang Lagoon (Xiamen, Fujian Province, China), which is a eutrophic waterbody. The total phosphorus (TP), ammonium nitrogen (NH₄⁺-N), and total organic carbon (TOC) levels in the overlying water were measured at regular intervals, and the changes of different P forms in WTPS, Al-PIA, and sediment of each system were analyzed before and after the test. The average TP reduction rates of LMB, Al-PIA, WTPS, and QS were 94.82, 92.14, 86.88, and 10.68%, respectively, when the release strength of sediment TP was 2.26–9.19 mg/(m²·d) and the capping strength of the materials was 2 kg/m². Thin-layer capping of LMB, WTPS, and Al-PIA could effectively control P release from the sediment (P<0.05). However, thin-layer capping of LMB, Al-PIA, and QS did not significantly reduce the release of ammonium N and organic matter (P > 0.05). Based on our results, LMB, Al-PIA, and WTPS thin-layer capping promoted the migration and transformation of easily released P in sediment. The P adsorbed by WTPS and Al-PIA mainly occurred in the form of NAIP.     

Co-pyrolysis of oil sludge with hydrogen-rich plastics in a vertical stirring reactor: Kinetic analysis,emissions, and products

● Collaborative treatment of plastics and OS was established to improve oil quality. ● PE addition successfully improved OS pyrolysis process by deploying H/C_eff ratio. ● Higher H/C_eff ratio promoted cracking to obtain more gas and light oil fractions. ● The degradation of PE and OS was promoted each other under their temperature range. Pyrolysis is an effective method to treat oily sludge (OS) due to its balance between oil recovery and nonhazardous disposal. However, tank bottom OS contains a high content of heavy fractions, which creates obstacles for pyrolysis due to the high activation energy. The incomplete cracking of macromolecules and secondary polymerization decreases the oil quality and causes coking during the operation process. This study introduced polyethylene (PE) into OS to deploy the H/C_eff ratio of feedstocks for pyrolysis. A strong interaction between OS and PE during copyrolysis could be observed from the TG/DTG curves. PE tightly participated in OS degradation, while OS also promoted PE degradation at high temperature. Apparent pits were generated in solid residues from copyrolysis, which was attributed to the uniform and violent gas release. In addition to HCN, other nitrogenous and sulphurous pollutants were inhibited. Accordingly, more gas products were attained after PE addition with more value-added compositions of alkanes and alkenes. Although the oil yield decreased after PE addition, the oil products from copyrolysis possessed higher heating values and higher contents of light fractions with short chains as well as paraffins. Consequently, copyrolysis of OS and PE significantly improved the pyrolysis process and resulted in high oil quality.     

Spatiotemporal variations of dissolved organic matter in a typical multi-source watershed in northern China: a fluorescent evidence

Environmental Science and Pollution Research - The amount of dissolved organic matter (DOM) in a multi-source watershed is important for complete management and assessing the river basin’s...     

Emission inventory and control policy for non-road construction machinery in Tianjin

Environmental Science and Pollution Research - The establishment of a non-road construction machinery emission inventory forms the basis for the analysis of pollutant emission characteristics and...     

Impact of air pollutants on hospital visits for pediatric asthma in Fuzhou city,southeast China

Environmental Science and Pollution Research - Rapid social development in China has resulted in severe air pollution and adverse impacts on people’s health. Although studies have been...