Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performa...Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performance. This study examined the interactive effects of elevated [CO2] and nitrogen supply on the eco-physiological performance of yellow birch. Seedlings were exposed to two [CO2] levels and five nitrogen supply levels for 4 months. Growth parameters such as seedling height and root collar diameter increased with higher nitrogen supply and elevated [CO2], while specific leaf area decreased. [CO2] elevation and increasing nitrogen supply also increased the total and stem, and leaf biomass. The elevated [CO2] increased the stem mass ratio but decreased the root-to-shoot ratio and root mass ratio. However, decreases in nitrogen supply increased root mass ratio and root-to-shoot ratio. The elevated [CO2] increased the maximum rate of Rubisco carboxylation (Vcmax) and photosynthetic electron transport (Jmax), but the effect on Jmax was statistically significant only at the two highest nitrogen supply levels. The results indicate that yellow birch may increase photosynthetic capacity, biomass, and growth in the future when [CO2] is higher.展开更多
In this study,the polyurethanes(PU)were synthesized from 4,4′-methylene diphenyl diisocyanate and biobased ethoxylated castor oil or one to one mixture of ethoxylated and neat castor oil by direct mixing method.Utili...In this study,the polyurethanes(PU)were synthesized from 4,4′-methylene diphenyl diisocyanate and biobased ethoxylated castor oil or one to one mixture of ethoxylated and neat castor oil by direct mixing method.Utilization of ethoxylated castor oil increases tensile strength of PU up to 2.75 times(from3.2 to 8.8MPa),compared to PU based on neat castor oil.The PU composites filed with birch flour,diatomite and their mixture were prepared using home-made dissolver with cutter-shaped attachment at the speed of 1500 min−1.The tensile strength of PU composites filled with birch flour increases up to two time at loading 5–30 wt.%.Application of combined birch flour/diatomite additives has similar effect.The tensile strength of PU composites based on one to one mixture of ethoxylated and neat castor oil and filled with birch flour or combined birch flour/diatomite additives increases sharply up to 16–17 fold(up to 18.1 MPa).The birch flour and diatomite wellsoaked polymer matrix.The main factor determining mechanical performance is the morphology of PU samples and composites.Formation of ordered lamella-like structure of amorphous phase of PU matrix leads to an increase in mechanical performance and glass transition temperatures.Formation of disordered unstructured soft phase of starting PU leads to a decline of these functional properties.展开更多
Instead of the traditional linear model of taking,making,and disposing,the circular bio-economy promotes a regenerative approach.Although there is potential to create valuable products like betulin,lupeol,and suberini...Instead of the traditional linear model of taking,making,and disposing,the circular bio-economy promotes a regenerative approach.Although there is potential to create valuable products like betulin,lupeol,and suberinic acids(SA)from outer birch bark,many industries,such as plywood and pulp,often choose to incinerate substan-tial amounts of leftover birch bark to meet their energy needs.This highlights the importance of obtaining valu-able products from wood.The objective of this study was to examine various fractions of SA and assess their potential for wood impregnation.The fractions included SA potassium salts in ethanol(SAK-EtOH)and water(SAK-H2O),SA suspension in water(SAS-H2O)and dried SA,which was subsequently diluted in ethanol(DSA-EtOH).There is significant potential for utilizing SA in wood treatment formulations as a sustainable alternative to harmful petroleum-derived chemicals.This approach not only addresses environmental concerns but also enhances the functionality of wood in construction applications,such as improving impregnation for moisture and fungal protection.Among the solutions tested,the ethanol solution of SA,specifically DSA-EtOH,showed the highest weight percent gain(WPG)and the greatest leaching resistance.GPC analysis showed that SA salts in ethanol(SAK-EtOH)and water(SAK-H2O)predominantly consist of low molecular fractions and each process(acidification and drying)reduces the low molecular content in the sample.This suggests that SA polymerizes after drying,making it necessary to dissolve it in ethanol to meet the requirements for impregnation.Further opti-mization,including adjustments in the concentration of the SA ethanol solution and the curing temperature,is essential to identify the optimal conditions for more in-depth impregnation studies.展开更多
精准的分布式光伏短期发电功率预测有助于电力系统运行与功率就地平衡。该文提出一种基于BIRCH(balanced iterative reducing and clustering using hierarchies)相似日聚类的L-Transformer(LSTM-Transformer)模型进行短期光伏功率预测...精准的分布式光伏短期发电功率预测有助于电力系统运行与功率就地平衡。该文提出一种基于BIRCH(balanced iterative reducing and clustering using hierarchies)相似日聚类的L-Transformer(LSTM-Transformer)模型进行短期光伏功率预测。首先使用BIRCH无监督聚类算法对历史数据聚类得到3种典型天气,根据聚类结果划分测试集对模型进行训练。为提高不同天气类型下的预测精度,采用双层架构的L-Transformer模型,首层通过长短期记忆网络(long short term memory,LSTM)的门控单元机制捕捉时间序列中的长期依赖关系;次层结合Transformer模型的自注意力机制聚焦于当前任务更关键的特征量,通过多注意力头与光伏数据特征量相结合生成向量,注意力头并行计算,从而高效、精确地预测短期光伏功率。实测数据验证结果表明L-Transformer模型对于不同天气类型功率预测泛化性优异、精确度高,气象数据波动大时鲁棒性强。展开更多
Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The hig...Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The highest and the lowest level of genetic differentiation were detected in B. ovalifolia and B. maximowicziana Regel respectively. In these eight species, genetic diversity of birch (HT) was 24.38 %, and the genetic variation (GST ) interspecies was accounting for 79.36% of total genetic variation. According to the cluster results of genetic distance, the eight species were classified into three groups as B. davurica, B. ovalifolia, B. platyphylla and B. pendula for one group; B. schmidtii, B. costata and B. ermanii Cham. var. communis for one group, and B. maximowicziana Regel for another group. The result of cluster is consistent with traditional morphological classification.展开更多
岩相及孔隙度预测在油气勘探中非常重要,为此,提出一种基于多阈值BIRCH(Balanced Iterative Reducing and Clustering Using Hierarchies)聚类的岩相预测方法,并以此为基础利用岭回归算法预测孔隙度。首先,根据地震波阻抗数据分布规律...岩相及孔隙度预测在油气勘探中非常重要,为此,提出一种基于多阈值BIRCH(Balanced Iterative Reducing and Clustering Using Hierarchies)聚类的岩相预测方法,并以此为基础利用岭回归算法预测孔隙度。首先,根据地震波阻抗数据分布规律启发式设定初始阈值,根据簇之间体积的不一致性,动态增加阈值,使用Agglomerative算法进行全局聚类以划分岩相;然后,以井点处孔隙度和地震波阻抗数据为输入,在同一岩相内采用改进的岭回归方法预测孔隙度。模型实验表明,多阈值BIRCH聚类方法具有良好的稳定性和较高的计算效率,岩相划分准确。实际数据结果表明,该方法能够准确预测孔隙度。展开更多
文摘Climate change impacts soil nitrogen, influencing plant responses to elevated atmospheric [CO2]. Understanding the interaction between nitrogen supply and elevated [CO2] is crucial for predicting plant future performance. This study examined the interactive effects of elevated [CO2] and nitrogen supply on the eco-physiological performance of yellow birch. Seedlings were exposed to two [CO2] levels and five nitrogen supply levels for 4 months. Growth parameters such as seedling height and root collar diameter increased with higher nitrogen supply and elevated [CO2], while specific leaf area decreased. [CO2] elevation and increasing nitrogen supply also increased the total and stem, and leaf biomass. The elevated [CO2] increased the stem mass ratio but decreased the root-to-shoot ratio and root mass ratio. However, decreases in nitrogen supply increased root mass ratio and root-to-shoot ratio. The elevated [CO2] increased the maximum rate of Rubisco carboxylation (Vcmax) and photosynthetic electron transport (Jmax), but the effect on Jmax was statistically significant only at the two highest nitrogen supply levels. The results indicate that yellow birch may increase photosynthetic capacity, biomass, and growth in the future when [CO2] is higher.
文摘In this study,the polyurethanes(PU)were synthesized from 4,4′-methylene diphenyl diisocyanate and biobased ethoxylated castor oil or one to one mixture of ethoxylated and neat castor oil by direct mixing method.Utilization of ethoxylated castor oil increases tensile strength of PU up to 2.75 times(from3.2 to 8.8MPa),compared to PU based on neat castor oil.The PU composites filed with birch flour,diatomite and their mixture were prepared using home-made dissolver with cutter-shaped attachment at the speed of 1500 min−1.The tensile strength of PU composites filled with birch flour increases up to two time at loading 5–30 wt.%.Application of combined birch flour/diatomite additives has similar effect.The tensile strength of PU composites based on one to one mixture of ethoxylated and neat castor oil and filled with birch flour or combined birch flour/diatomite additives increases sharply up to 16–17 fold(up to 18.1 MPa).The birch flour and diatomite wellsoaked polymer matrix.The main factor determining mechanical performance is the morphology of PU samples and composites.Formation of ordered lamella-like structure of amorphous phase of PU matrix leads to an increase in mechanical performance and glass transition temperatures.Formation of disordered unstructured soft phase of starting PU leads to a decline of these functional properties.
基金supported according to contract No.5.1.1.2.i.0/1/22/A/CFLA/007 between“Forest Sector Competence Centre of Latvia”Ltd.the Central Finance and Contracting Agency which dated 20th January of 2023.
文摘Instead of the traditional linear model of taking,making,and disposing,the circular bio-economy promotes a regenerative approach.Although there is potential to create valuable products like betulin,lupeol,and suberinic acids(SA)from outer birch bark,many industries,such as plywood and pulp,often choose to incinerate substan-tial amounts of leftover birch bark to meet their energy needs.This highlights the importance of obtaining valu-able products from wood.The objective of this study was to examine various fractions of SA and assess their potential for wood impregnation.The fractions included SA potassium salts in ethanol(SAK-EtOH)and water(SAK-H2O),SA suspension in water(SAS-H2O)and dried SA,which was subsequently diluted in ethanol(DSA-EtOH).There is significant potential for utilizing SA in wood treatment formulations as a sustainable alternative to harmful petroleum-derived chemicals.This approach not only addresses environmental concerns but also enhances the functionality of wood in construction applications,such as improving impregnation for moisture and fungal protection.Among the solutions tested,the ethanol solution of SA,specifically DSA-EtOH,showed the highest weight percent gain(WPG)and the greatest leaching resistance.GPC analysis showed that SA salts in ethanol(SAK-EtOH)and water(SAK-H2O)predominantly consist of low molecular fractions and each process(acidification and drying)reduces the low molecular content in the sample.This suggests that SA polymerizes after drying,making it necessary to dissolve it in ethanol to meet the requirements for impregnation.Further opti-mization,including adjustments in the concentration of the SA ethanol solution and the curing temperature,is essential to identify the optimal conditions for more in-depth impregnation studies.
基金国家自然科学基金(the National Natural Science Foundation of China under Grant No.60273043)安徽省自然科学基金(the Natural Science Foundation of Anhui Province of China under Grant No.050460402)
文摘精准的分布式光伏短期发电功率预测有助于电力系统运行与功率就地平衡。该文提出一种基于BIRCH(balanced iterative reducing and clustering using hierarchies)相似日聚类的L-Transformer(LSTM-Transformer)模型进行短期光伏功率预测。首先使用BIRCH无监督聚类算法对历史数据聚类得到3种典型天气,根据聚类结果划分测试集对模型进行训练。为提高不同天气类型下的预测精度,采用双层架构的L-Transformer模型,首层通过长短期记忆网络(long short term memory,LSTM)的门控单元机制捕捉时间序列中的长期依赖关系;次层结合Transformer模型的自注意力机制聚焦于当前任务更关键的特征量,通过多注意力头与光伏数据特征量相结合生成向量,注意力头并行计算,从而高效、精确地预测短期光伏功率。实测数据验证结果表明L-Transformer模型对于不同天气类型功率预测泛化性优异、精确度高,气象数据波动大时鲁棒性强。
基金This paper was supported by Northeast Forestry University.
文摘Genetic relationships of eight species of genus Betula were evaluated using ISSR marks. A total of 236 loci were generated from 17 ISSR primers. Percentage of polymorphic bands (PPB) varied from 5.93 to 19.92. The highest and the lowest level of genetic differentiation were detected in B. ovalifolia and B. maximowicziana Regel respectively. In these eight species, genetic diversity of birch (HT) was 24.38 %, and the genetic variation (GST ) interspecies was accounting for 79.36% of total genetic variation. According to the cluster results of genetic distance, the eight species were classified into three groups as B. davurica, B. ovalifolia, B. platyphylla and B. pendula for one group; B. schmidtii, B. costata and B. ermanii Cham. var. communis for one group, and B. maximowicziana Regel for another group. The result of cluster is consistent with traditional morphological classification.
文摘岩相及孔隙度预测在油气勘探中非常重要,为此,提出一种基于多阈值BIRCH(Balanced Iterative Reducing and Clustering Using Hierarchies)聚类的岩相预测方法,并以此为基础利用岭回归算法预测孔隙度。首先,根据地震波阻抗数据分布规律启发式设定初始阈值,根据簇之间体积的不一致性,动态增加阈值,使用Agglomerative算法进行全局聚类以划分岩相;然后,以井点处孔隙度和地震波阻抗数据为输入,在同一岩相内采用改进的岭回归方法预测孔隙度。模型实验表明,多阈值BIRCH聚类方法具有良好的稳定性和较高的计算效率,岩相划分准确。实际数据结果表明,该方法能够准确预测孔隙度。
