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排序方式: 共有13条查询结果,搜索用时 31 毫秒
1.
A series of sulfonated (S) phthalimidomethyl (P) zinc phthalocyanines (Pc) was synthesized in a reaction, in which both kinds of substituents were introduced to ZnPc simultaneously. The products were separated by HPLC. The five different fractions obtained were further purified by a membrane separation method, and then characterized by UV/Vis, IR, element analysis and the abilities to generate singlet oxygen upon irradiation by light as well as a preliminary determination of in vitro antitumor activities. The results show that one of the five separating parts with formula of ZnPcS2P2 exhibited rather good PDT activity. The compound was further characterized by NMR, MS and thermal analysis. Studies on in vivo antitumor activities of ZnPcS2P2 as photosensi-tizer show that its inhibitory rate was up to 89.8% and 90.8% for S180 and U14 solid tumors transplanted in mice respectively when the dosage of drug was 2 mg/kg and the dosage of laser light with 670 nm wavelength was 72 J/cm2. Several structural factor  相似文献   
2.
基于平稳小波和相空间重构的激光混沌预测   总被引:2,自引:2,他引:0  
相征  张太镒  孙建成 《光子学报》2005,34(11):1756-1760
提出了一种激光混沌时间序列预测算法.该算法通过平稳小波分解,将原始数据序列分解为与原序列等长的尺度系数和小波系数,利用坐标延迟理论,重建各级尺度系数和各级小波系数的相空间,再根据混沌吸引子的稳定性和分形性,在相空间中对尺度系数和小波系数进行预测,进而通过平稳小波重构算法,实现了时间序列的非线性预测.该算法对数据可以进行更平滑的处理,比无小波算法预测的时间范围更长.通过仿真试验说明,原始时间数据序列被成功的重建,说明算法能够有效的对非线性动态系统的时间序列进行建模和预测.  相似文献   
3.
孙建成  张太镒  刘枫 《中国物理》2004,13(12):2045-2052
Positive Lyapunov exponents cause the errors in modelling of the chaotic time series to grow exponentially. In this paper, we propose the modified version of the support vector machines (SVM) to deal with this problem. Based on recurrent least squares support vector machines (RLS-SVM), we introduce a weighted term to the cost function tocompensate the prediction errors resulting from the positive global Lyapunov exponents. To demonstrate the effectiveness of our algorithm, we use the power spectrum and dynamic invariants involving the Lyapunov exponents and the correlation dimension as criterions, and then apply our method to the Santa Fe competition time series. The simulation results shows that the proposed method can capture the dynamics of the chaotic time series effectively.  相似文献   
4.
用直接取代法合成得到含磺基和邻苯二甲酰亚胺甲基的一系列双取代的酞菁锌化合物, 产物经反相高效液相色谱法分离得5种不同组分, 经膜分离法进一步纯化和浓缩后, 用元素分析、红外光谱等进行表征. 测定各组分在光照下产生单线态氧的能力,并通过离体试验比较它们杀伤癌细胞的能力. 对其中具有较高光动力抗癌活性的物种二磺基二邻苯二甲酰亚胺甲基酞菁锌(ZnPcS2P2)进一步用紫外可见光谱、核磁、热分析、质谱等方法进行结构表征. 研究了ZnPcS2P2的在体抗肿瘤活性, 结果表明, 在670 nm激光的激发下(光照剂量为72 J/cm2), ZnPcS2P2(药剂量为2 mg/kg)对小鼠的U14和S180移植瘤的抑瘤率分别达到89.8%和90.8%. 探讨了构效关系, 初步分析了ZnPcS2P2具有较高活性的结构原因.  相似文献   
5.
Based on the classical Gaussian process (GP) model, we propose a multi-scale Gaussian process (MGP) model to predict the existence of chaotic time series. The MGP employs a covariance function that is constructed by a scaling function with its different dilations and translations, ensuring that the optimal hyperparameter is easy to determine. Moreover, the scaling function with its different dilations and translations can form a set of complete bases, resulting in the fact that the MGP can acquire better prediction performance than the GP. The experiments can lead to the following conclusions: (i) The MGP gives a relatively better prediction performance in comparison with the classical GP model. (ii) The prediction performance of the MGP is competitive with support vector machine (SVM). They give better performance as compared to the radial basis function networks.  相似文献   
6.
不同激发波长下ZnPcSP的光敏化能力和抗癌活性   总被引:2,自引:0,他引:2  
研究了激发光的波长对金属酞菁配合物ZnPcSP光敏化产生O2的能力和光动力癌作用的影响,结果表明,激发波长对ZnPcSP配合物光敏化产生O2的能力和光动力抗癌作用的影响显示了同样的规律性,波长为670nm的光具有较佳的激发效率,研究结果同时说明ZnPcSP在光动力治癌中的主要光敏反应机制可能是产生O2的Ⅱ型反应机制。  相似文献   
7.
合成了2个酞菁锌配合物,即α-四(4-(4-乙酰哌嗪)苯氧基))酞菁锌(C80H72N16O8Zn) (1)和β-四(4-(4-乙酰哌嗪)苯氧基)酞菁锌(C80H72N16O8Zn) (2),并通过1H NMR,MS,IR和元素分析等手段进行表征。配合物12在N,N-二甲基甲酰胺、四氢呋喃和正辛醇等有机溶剂中呈现出典型的酞菁的单体吸收光谱特征,Q带分别位于693~698 nm和681~682 nm,相对于β位取代者,α位取代的配合物的Q带明显红移。在含水溶剂中的吸收光谱测试显示,α位取代较β位取代更能有效地阻止配合物在含水溶剂中形成聚集体。通过吸收光谱和荧光光谱研究了2个配合物与血清白蛋白(BSA,HSA)和转铁蛋白(apoTf)的相互作用,结果表明,结合常数在(1~20) × 105 mol-1·L之间,相对而言, β位取代的配合物与白蛋白的结合能力强于α位取代者。同时,制备了1-BSA、2-BSA、1-HSA、1-apoTf和1-FeTf等非共价键结合的酞菁-蛋白质复合物。对MCF-7乳腺癌细胞的光动力杀伤作用的测试初步表明,复合物的活性较高,活性顺序为:1-BSA > 1-FeTf > 1-HSA,1-apoTf > 2-BSA > 1 > 2。  相似文献   
8.
孙建成 《中国物理 B》2012,21(10):100502-100502
Least-square support vector machines(LS-SVM) are applied for learning the chaotic behavior of Chua’s circuit.The system is divided into three multiple-input single-output(MISO) structures and the LS-SVM are trained individually.Comparing with classical approaches,the proposed one reduces the structural complexity and the selection of parameters is avoided.Some parameters of the attractor are used to compare the chaotic behavior of the reconstructed and the original systems for model validation.Results show that the LS-SVM combined with the MISO can be trained to identify the underlying link among Chua’s circuit state variables,and exhibit the chaotic attractors under the autonomous working mode.  相似文献   
9.
孙建成 《中国物理》2007,16(11):3262-3270
Long-term prediction of chaotic time series is very difficult,for the Chaos restricts predictability.in this paper a new method is studied to model and predict chaotic time series based on minimax probability machine regression (MPMR). Since the positive global Lyapunov exponents lead the errors to increase exponentially in modelling the chaotic time series, a weighted term is introduced to compensate a cost function. Using mean square error (MSE) and absolute error (AE) as a criterion, simulation results show that the proposed method is more effective and accurate for multistep prediction. It can identify the system characteristics quite well and provide a new way to make long-term predictions of the chaotic time series.[第一段]  相似文献   
10.
合成了一种轴向尼泊金甲酯取代的酞菁硅,即二(4-甲酯基苯氧基)酞菁硅,并通过IR,NMR,HPLC和元素分析等手段进行了表征。研究了该配合物在不同溶剂中的电子吸收光谱和荧光光谱。结果表明,它在含2%Cremophor EL,20%丙二醇的生理盐水中,以单体形式存在,Q带最大吸收位于683 nm附近,相应的摩尔吸光系数为7.47×104mol-1.L.cm-1,最大发射带位于690 nm附近,荧光量子产率为0.34,荧光寿命为4.7 ns。初步的离体光动力活性测试表明,该配合物对B16黑色素瘤细胞具有光动力灭活能力,半致死量LD50为1.2×10-4mol.L-1。  相似文献   
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