Soil acidification is an important process in land degradation around the world as well as in China.Acidification of Alfisols was investigated in the tea gardens with various years of tea cultivation in the eastern Ch...Soil acidification is an important process in land degradation around the world as well as in China.Acidification of Alfisols was investigated in the tea gardens with various years of tea cultivation in the eastern China.Cultivation of tea plants caused soil acidification and soil acidity increased with the increase of tea cultivation period.Soil pH of composite samples from cultivated layers decreased by 1.37,1.62 and 1.85,respectively,after 13,34 and 54 years of tea plantation,as compared to the surface soil obtained from the unused land.Soil acidification rates at early stages of tea cultivation were found to be higher than those at the later stages.The acidification rate for the period of 0-13 years was as high as 4.40 kmol H + ha ?1 year ?1 for the cultivated layer samples.Soil acidification induced the decrease of soil exchangeable base cations and base cation saturation and thus increased the soil exchangeable acidity.Soil acidification also caused the decrease of soil cation exchange capacity,especially for the 54-year-old tea garden.Soil acidification induced by tea plantation also led to the increase of soil exchangeable Al and soluble Al,which was responsible for the Al toxicity to plants.展开更多
This paper reports the biomimetic catalytic properties of new Schiff base mononuclear complexes MH 2L｛M = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L=bis[ N,N′-ethylene-2,2′-(phenylmethylene)bis(3...This paper reports the biomimetic catalytic properties of new Schiff base mononuclear complexes MH 2L｛M = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L=bis[ N,N′-ethylene-2,2′-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)]｝and dinuclear complexes MnML[M=Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)] for studying the monooxygenation of cyclohexane with PhIO and magnetic properties of the dinuclear complexes. The investigation of the magnetic properties(4—300 K) of the dinuclear complexes revealed that their antiferromagnetic spin exchange with J varied from -10.49 to -0.482 cm -1 except MnZnL, and antiferromagnetic spin exchange decreased in the order: Mn(Ⅱ)-Cu(Ⅱ)>Mn(Ⅱ)-Ni(Ⅱ)>Mn(Ⅱ)-Mn(Ⅱ)>Mn(Ⅱ)- Fe(Ⅲ)>Mn(Ⅱ)-Co(Ⅱ)>Mn(Ⅱ)-Cr(Ⅲ). The yield determination of monooxygenation of cyclohexane indicated that the catalytic reactivity of the dinuclear complex was better than that of the corresponding mononuclear complex, so we supposed that there was some cooperative action between the two metals in these dinuclear complexes. It was found that the cooperation lay in the decreasing order: Mn-{Fe>}Mn-Cr>Mn-Cu>Mn-Mn>Mn-Co>Mn-Ni>Mn-Zn. It seems that this cooperation increased with the increase of the number of unpaired d electrons and the magnetic exchange between the two metals in these dinuclear complexes.展开更多
A novel approach to survivor memory unit of Decision Feedback Sequence Estimator(DFSE) for 1000BASE-T transceiver based on hybrid architecture of the classical register-exchange and trace-back methods is proposed.The ...A novel approach to survivor memory unit of Decision Feedback Sequence Estimator(DFSE) for 1000BASE-T transceiver based on hybrid architecture of the classical register-exchange and trace-back methods is proposed.The proposed architecture is investigated with special emphasis on low power and small decoder latency,in which a dedicated register-exchange module is designed to provide tentative survivor symbols with zero latency,and a high-speed trace back logic is presented to meet the tight latency budget specified for 1000BASE-T transceiver.Furthermore,clock-gating register banks are constructed for power saving.VLSI implementation reveals that,the proposed architecture provides about 40% savings in power consumption compared to the traditional register-exchange architecture.展开更多
针对基本交换的安全性和时间开销的正反两个方面,论述了密题计算机制,利用不同的组网方式测量了基本交换的时间开销,通过计算样本均值和标准差分析了其性能的优劣,提出了HIP BE Anti-Spam模型体系结构。该结构根据HIP基本交换的特点及...针对基本交换的安全性和时间开销的正反两个方面,论述了密题计算机制,利用不同的组网方式测量了基本交换的时间开销,通过计算样本均值和标准差分析了其性能的优劣,提出了HIP BE Anti-Spam模型体系结构。该结构根据HIP基本交换的特点及其内建的密题机制,结合出站和入站的双重过滤来防范和阻止垃圾邮件;利用HIP基本交换机制增大垃圾邮件发送源头的代价和成本,防御对邮件服务的DoS攻击,明确了进一步优化HIP BE Anti-Spam模型及算化的研究方向。展开更多
A series of 2 (E) (4 hydroxy 3 methoxybenzylidene) 5 (N substituted ami nomethyl) cyclopentanones was synthesized and evaluated for the anti inflammatory activity. All of the target compounds were confirmed ...A series of 2 (E) (4 hydroxy 3 methoxybenzylidene) 5 (N substituted ami nomethyl) cyclopentanones was synthesized and evaluated for the anti inflammatory activity. All of the target compounds were confirmed by spectral analysis and elemental analysis. Preliminary pharmacological tests showed that several compounds exerted appreciable inhibitory effect on xylene induced ear edema in mice and that alteration of the substituents of anilines had significant influence in anti inflammatory potency.展开更多
基金Supported by the National Nature Science Foundation of China (No. 30872009)the Earmarked Fund for Modern Agro-Industry Technology Research System of China (No. nycytx-23)
文摘Soil acidification is an important process in land degradation around the world as well as in China.Acidification of Alfisols was investigated in the tea gardens with various years of tea cultivation in the eastern China.Cultivation of tea plants caused soil acidification and soil acidity increased with the increase of tea cultivation period.Soil pH of composite samples from cultivated layers decreased by 1.37,1.62 and 1.85,respectively,after 13,34 and 54 years of tea plantation,as compared to the surface soil obtained from the unused land.Soil acidification rates at early stages of tea cultivation were found to be higher than those at the later stages.The acidification rate for the period of 0-13 years was as high as 4.40 kmol H + ha ?1 year ?1 for the cultivated layer samples.Soil acidification induced the decrease of soil exchangeable base cations and base cation saturation and thus increased the soil exchangeable acidity.Soil acidification also caused the decrease of soil cation exchange capacity,especially for the 54-year-old tea garden.Soil acidification induced by tea plantation also led to the increase of soil exchangeable Al and soluble Al,which was responsible for the Al toxicity to plants.
文摘This paper reports the biomimetic catalytic properties of new Schiff base mononuclear complexes MH 2L｛M = Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ); L=bis[ N,N′-ethylene-2,2′-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)]｝and dinuclear complexes MnML[M=Mn(Ⅱ), Fe(Ⅲ)Cl, Cr(Ⅲ)Cl, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ)] for studying the monooxygenation of cyclohexane with PhIO and magnetic properties of the dinuclear complexes. The investigation of the magnetic properties(4—300 K) of the dinuclear complexes revealed that their antiferromagnetic spin exchange with J varied from -10.49 to -0.482 cm -1 except MnZnL, and antiferromagnetic spin exchange decreased in the order: Mn(Ⅱ)-Cu(Ⅱ)>Mn(Ⅱ)-Ni(Ⅱ)>Mn(Ⅱ)-Mn(Ⅱ)>Mn(Ⅱ)- Fe(Ⅲ)>Mn(Ⅱ)-Co(Ⅱ)>Mn(Ⅱ)-Cr(Ⅲ). The yield determination of monooxygenation of cyclohexane indicated that the catalytic reactivity of the dinuclear complex was better than that of the corresponding mononuclear complex, so we supposed that there was some cooperative action between the two metals in these dinuclear complexes. It was found that the cooperation lay in the decreasing order: Mn-{Fe>}Mn-Cr>Mn-Cu>Mn-Mn>Mn-Co>Mn-Ni>Mn-Zn. It seems that this cooperation increased with the increase of the number of unpaired d electrons and the magnetic exchange between the two metals in these dinuclear complexes.
文摘A novel approach to survivor memory unit of Decision Feedback Sequence Estimator(DFSE) for 1000BASE-T transceiver based on hybrid architecture of the classical register-exchange and trace-back methods is proposed.The proposed architecture is investigated with special emphasis on low power and small decoder latency,in which a dedicated register-exchange module is designed to provide tentative survivor symbols with zero latency,and a high-speed trace back logic is presented to meet the tight latency budget specified for 1000BASE-T transceiver.Furthermore,clock-gating register banks are constructed for power saving.VLSI implementation reveals that,the proposed architecture provides about 40% savings in power consumption compared to the traditional register-exchange architecture.
文摘针对基本交换的安全性和时间开销的正反两个方面,论述了密题计算机制,利用不同的组网方式测量了基本交换的时间开销,通过计算样本均值和标准差分析了其性能的优劣,提出了HIP BE Anti-Spam模型体系结构。该结构根据HIP基本交换的特点及其内建的密题机制,结合出站和入站的双重过滤来防范和阻止垃圾邮件;利用HIP基本交换机制增大垃圾邮件发送源头的代价和成本,防御对邮件服务的DoS攻击,明确了进一步优化HIP BE Anti-Spam模型及算化的研究方向。
文摘A series of 2 (E) (4 hydroxy 3 methoxybenzylidene) 5 (N substituted ami nomethyl) cyclopentanones was synthesized and evaluated for the anti inflammatory activity. All of the target compounds were confirmed by spectral analysis and elemental analysis. Preliminary pharmacological tests showed that several compounds exerted appreciable inhibitory effect on xylene induced ear edema in mice and that alteration of the substituents of anilines had significant influence in anti inflammatory potency.
