Pollution trend in the tumen river and its influence on regional development

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含铁闪锌矿热容的实验测定与分析

利用美国ＤｕＰｏｎｔ公司的９９００型差示扫描量热仪对３个含铁闪锌矿样品的热容进行了实验测定,并讨论了定压摩尔热容实验值与实验温度的关系。实验结果表明,在实验条件下,含铁闪锌矿的定压摩尔热容与纯闪锌矿的定压摩尔热容存在显著差异,Ｆｅ置换Ｚｎ是造成这种差异的主要原因。     

偏心荷载下溶洞顶板冲切破坏上限分析

针对冲切破坏模式下溶洞顶板极限承载力问题,进行了不同顶板厚度以及不同荷载偏心距下溶洞顶板极限承载力室内试验研究,依据试验结果将偏心荷载作用下的溶洞冲切破坏假定为轴对称问题,引入Griffith强度准则,基于极限分析上限法,提出了一种适用于轴对称和偏心荷载作用下溶洞顶底板极限承载力的计算方法,并给出了能发生冲切破坏范围的估算方法。试验结果表明：在同一偏心距下,随着顶板厚度的增加,在达到基岩极限承载力之前,顶板极限承载力呈线性增长;当顶板厚度一定时,顶板极限承载力随着偏心距的增加呈非线性增长,偏心距e在能发生冲切破坏的范围之外时趋于平缓,并逐渐达到基岩极限承载力;理论计算结果与试验结果吻合较好。     

三门峡水库水文要素整编计算软件的设计与实现

本文针对三门峡水库工作实际,分析了目前数字技术条件下三门峡水库水文要素摘录蓄水量计算工作所处的困境和应解决的具体问题,以此为基础提出了三门峡水库水文要素整编计算软件的系统组成和功能模块构成,实现并完成了系统功能设计。     

Heat capacity and phase equilibria of wadeite-type K2Si4O9

The low-temperature heat capacity (C _p) of Si-wadeite (K₂Si₄O₉) synthesized with a piston cylinder device was measured over the range of 5–303 K using the heat capacity option of a physical properties measurement system. The entropy of Si-wadeite at standard temperature and pressure calculated from the measured heat capacity data is 253.8 ± 0.6 J mol⁻¹ K⁻¹, which is considerably larger than some of the previous estimated values. The calculated phase transition boundaries in the system K₂O–Al₂O₃–SiO₂ are generally consistent with previous experimental results. Together with our calculated phase boundaries, seven multi-anvil experiments at 1,400 K and 6.0–7.7 GPa suggest that no equilibrium stability field of kalsilite + coesite intervenes between the stability field of sanidine and that of coesite + kyanite + Si-wadeite, in contrast to previous predictions. First-order approximations were undertaken to calculate the phase diagram in the system K₂Si₄O₉ at lower pressure and temperature. Large discrepancies were shown between the calculated diagram compared with previously published versions, suggesting that further experimental or/and calorimetric work is needed to better constrain the low-pressure phase relations of the K₂Si₄O₉ polymorphs. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

老黏土地基承载力的确定

对比分析了各种确定地基承载力的方法,阐述了理论公式计算确定老黏土地基承载力的重要性.结合武昌地区的工程实例,用各种方法计算确定了老黏土的地基承载力值.研究表明,原位测试方法得到的承载力值偏低,而理论公式计算较合理.为了提高老黏土地基承载力的可信度和精度,在岩土工程勘察中除采用原位测试方法外,有必要结合理论公式计算来获取老黏土地基承载力值.     

国家经济增速与国家竞争力/影响力的时空关系

经济发展速度一直是各国家经济发展水平的重要测度指标,但国家经济增速与国家竞争/影响力之间的关系及可能的阈值需要进行深入地研究,尤其是在中国经济增速下滑的背景下,迫切需要阐释经济增速下降是否影响国家竞争力/影响力。在评述既有研究进展的基础上,采用时空分析路径,探讨国家经济发展速度与国家竞争力/影响力的时空关系。首先,从历史的角度分析了15世纪以来世界权力中心的演变路径,考察了英国、美国等世界权力中心的国家经济增速变化,总结其发展规律,考察国家影响力与国家经济增速之间的对应关系。然后着眼于空间视角,考察目前国家经济增速与国家竞争力的空间分异,尤其是考察两者之间关系的分异关系,总结主要特征与规律。研究发现国家经济增速与国家影响力之间并非存在严格的线性关系,但国家影响力的培育与强化仍需要一定的经济增速进行支撑,而国家经济增速与国家竞争力之间呈现逆向的对应关系,经济高速增长的国家往往竞争力较低,竞争力较高的国家往往有较低的经济增速甚至负增长。     

基于PS-DR-DP理论模型的区域资源环境承载力综合评价（英文）

The concepts of regional resources and environmental carrying capacity are important aspects of both academic inquiry and government policy. Although notable results have been achieved in terms of evaluating both these variables, most researchers have utilized a traditional analytical method that incorporates the "pressure-state-response" model. A new approach is proposed in this study for the comprehensive evaluation of regional resources and environmental carrying capacity; applying a "pressure-support", "destructiveness-resilience", and "degradation-promotion"("PS-DR-DP") hexagon interaction theoretical model, we divided carrying capacity into these three pairs of interactive forces which correspond with resource supporting ability, environmental capacity, and risk-disaster resisting ability, respectively. Negative carrying capacity load in this context was defined to include pressure, destructiveness, and degradation, while support, resilience, and promotion comprised positive attributes. The status of regional carrying capacity was then determined via the ratio between positive and negative contribution values, expressed in terms of changes in both hexagonal shape and area that result from interactive forces. In order to test our "PS-DR-DP" theory-based model, we carried out a further empirical study on Beijing over the period between 2010 and 2015. Analytical results also revealed that the city is now close to attaining a perfect state for both resources and environmental carrying capacity; the latter state in Beijing increased from 1.0143 to 1.1411 between 2010 and 2015, an improved carrying capacity despite the fact that population increased by two million. The average contribution value also reached 0.7025 in 2015, indicating that the city approached an optimal loading threshold at this time but still had space for additional carrying capacity. The findings of our analysis provide theoretical support to enable the city of Beijing to control population levels below 23 million by 2020.     

青藏高原草地地上生物量和理论载畜量

准确模拟和预测草地地上生物量(Aboveground biomass,AGB)和理论载畜量对于维持草地生态系统平衡、优化放牧管理至关重要。当前很多研究以围栏外草地AGB为基础,估算了青藏高原草地AGB的现存量。但是,牛羊啃食后的草地AGB现存量无法准确评估草地理论载畜量。围栏内草地不受家畜采食影响,其年际变率由环境因子驱动,可视为草地潜在AGB (potential AGB,AGB_p),更适用于草地理论载畜量的评估。本研究以青藏高原345个围栏内AGB观测数据为基础,结合气候、土壤和地形数据,利用随机森林算法构建草地潜在地上生物量估算模型,并对当前气候条件(2000-2018年)和未来20年(2021-2040年)4种气候变化情景(SSP1-2.6、SSP2-4.5、SSP3-7.0和SSP5-8.5)下的草地AGB_p和高寒草地理论载畜量进行模拟与预测。结果表明:(1)随机森林算法可准确模拟当前气候条件下的青藏高寒草地AGB_p(R²=0.76,P<0.001);2000-2018年青藏高寒草地AGB_p平均值为102.4 g m^-2,时间上增加趋势不明显(P>0.05);AGB_p年际波动和生长季降水显著正相关(R²=0.57,P<0.001),和生长季温度日较差显著负相关(R²=0.51,P<0.001)。(2)当前气候条件下,青藏高寒草地平均理论载畜量为0.94 SSU ha^-1(standardized sheep unit ha^-1);在过去20年约有54.1%草地理论载畜量呈提升状态。(3)和当前相比,未来20年青藏高原中部和北部草地AGB_p和理论载畜量呈下降态势。因此,建议未来在厘清气候变化影响下草畜关系的基础上进行有针对性的草牧业规划和管理,以缓解区域气候变化引起的草畜矛盾。     

玉米秸秆还田和有机配施提高黑土酸中和容量

长期施用化肥导致农田黑土酸化、盐基离子耗竭、养分失衡及作物重金属污染等诸多问题。本文依托吉林公主岭国家黑土肥效监测基地25 a的施肥试验,研究了不施肥对照（C）、N、NP、NK、PK、NPK、厩肥—化肥配施（MNPK）、玉米秸秆还田（SNPK）等8个施肥处理对土壤酸中和容量（ANC）的影响,N、P、K施用量分别为165 kg hm^-2 a^-1、36 kg hm^-2 a^-1、68.5 kg hm^-2 a^-1,MNPK和SNPK处理与NPK处理为等N量。结果表明,施化肥导致表土pH下降0.37~1.39,MNPK和SNPK处理分别提高土壤pH值0.21和0.53。以pH 5.0为参比,N、NP、NK、PK、NPK各处理的酸中和容量ANC_{pH 5.0}分别为对照的42.85%、61.79%、54.05%、82.26%、63.68%;MNPK处理的ANC_{pH 5.0}是对照的1.86倍;加酸160 mmol kg^-1,SNPK处理的土壤pH值仅从7.65降至6.42,表现出极强的酸中和能力。SNPK和MNPK处理的土壤交换性盐基总量SEB分别是对照的1.37和1.14倍,土壤有机质SOM分别是对照的1.32和1.63倍,二者是提高土壤ANC主要原因。总之,有机物料添加显著提高了黑土抗酸化性能及土壤基础肥力水平,研究结果可为东北黑土区玉米秸秆还田保护性耕作及有机肥部分替代化肥实践提供长期试验的理论依据和数据支撑。