Immunomodulatory effect of Ganoderma atrum polysaccharide on CT26 tumor-bearing mice

Ganoderma atrum has attracted great attention for its antitumor activity. However, the mechanism remains unclear. A G. atrum polysaccharide (PSG-1) showed pronounced antitumor activity in this study. PSG-1 did not kill CT26 cells directly, but inhibited the proliferation of CT26 cells via the activation of peritoneal macrophages (MΦ). In vivo, PSG-1 significantly suppressed the tumor growth in CT26 tumor-bearing mice. The treatment caused a significant increase in the immune organ index and the phagocytosis of macrophages. The production of TNF-α, IL-1β and nitric oxide also increased. Furthermore, we found that PSG-1 acted on Toll-like receptor (TLR) 4, signaled through p38 MAPK pathway, then activated NF-κB and stimulated TNF-α production. We further found that PSG-1 increased the expression of TLR4 and NF-κB, the degradation of IκBα and the phosphorylation of p38 MAPK. In summary, we have demonstrated that PSG-1 could activate macrophages via TLR4-dependent signaling pathways, improve immunity and inhibit tumor growth.     

一种基于奇偶分解的小波域图像数字水印方案

提出了一种基于奇偶分解的小波域图像数字水印方案。该算法将图像水印按照位置进行奇偶分解,将原始图像进行3级小波分解的低频小波系数按照位置进行奇偶分解,选择重要系数作为嵌入区域,并利用人眼视觉隐蔽特性自适应地调节水印嵌入强度,将水印嵌入到相应的系数中。仿真实验证明,该算法简单易行,对JPEG压缩、滤波等攻击均具有良好的鲁棒性。     

操作条件对死端微滤膜通量的影响--温度、压力、浓度的影响

采用标准孔径为0.1μm的亲水PVDF(聚偏氟乙烯)微滤膜和0.2μm的PTFE(聚四氟乙烯)膜,研究了温度、压力、浓度等操作条件对BSA溶液死端微滤膜通量的影响.实验表明,温度、压力和浓度对微滤膜通量有重要影响,通量随温度升高而增大;随浓度的增大而减小;当压力上升到0.14 MPa时,通量将不随压力变化,达到极限通量.在实验范围内(0.04~0.16 MPa,18~30℃),对于去离子水,通量和温度成良好的线性关系,通量随温度、压力的变化关系分别为ln(J/J)w=-0.021 9T-13.993和ln(J/Δp)w=-1.958 4Δp 5.283 4;对于BSA溶液,则在0.04~0.14 MPa,20~30℃范围内,通量随温度、压力的变化关系分别为JE/JT=ln(-0.004 5T2 0.230 9T)和ln(J/Δp)=-3.576 7Δp 4.627 7.溶液浓度增大,稳态通量下降;当溶液浓度达到一定值时,由于滤饼层厚度趋向平衡厚度,稳态通量将近似恒定.     

Internal Forces for Statically Indeterminate Structures Having Different Moduli in Tension and Compression

When a different tension-compression elastic modulus is introduced into the statically indeterminate structure, the flexural rigidity EI is no longer a constant, which is different from that of classic mechanics, but becomes the function of the internal force, the calculation of the internal force in the structure is a nonlinear problem. In light of this, the formula of internal force in statically indeterminate structures with different moduli has been deduced, the iterative program for calculating nonlinear internal force developed, and examples analyzed. Finally, we put forth reasonable suggestions for calculating this kind of structure and a new idea in optimizing the structures by using different modulus characters. A new and simple analytical-iterative method has been provided for calculating practical engineering problems by using different-modulus theory. This is different from the previous complete numerical solution, which characterizes complex calculation procedure, heavy calculation work, and slow convergence speed. Moreover, a new perspective has been provided for studying the mechanics characters of composite materials.     

差分型码分多址通信系统及相关技术

提出了一种带有瞬时位相调制技术的高性能差分型码分多址系统．该系统中的瞬时位相调制技术是当前最新通信技术之一，描述了π4-DQPSK瞬时位相调制的基本原理并画出了瞬时位相解调级框图．系统中应用了连续位相的Walsh码作为扩谱码，Walsh码的产生方法有较大创新．这两项最新技术的应用，提高了系统性能，有效地克服了多路瑞利衰减．     

漂珠/钡铁氧体复合材料的制备和吸波性能

采用溶胶-凝胶自蔓延燃烧法制备出漂珠/钡铁氧体低密度磁性复合材料,用扫描电镜、热重-差热分析仪、X射线衍射仪、振动样品磁强计和矢量网络分析仪表征了样品的形貌、结构、电磁性能和吸波性能。结果表明:在漂珠表面形成的钡铁氧体包覆层厚度为5-15 nm,颗粒粒径均小于60 nm。复合材料由六角晶钡铁氧体、α-氧化铁及少量莫来石和石英组成,其磁性能随钡铁氧体与漂珠质量比的增大而增强。复合材料在2-18 GHz频段具有较好的介电损耗和磁损耗性能,当吸波材料厚度为1.5 mm、在14.2 GHz处反射损耗峰值为-29.2 d B,反射损耗小于-10 dB的带宽为4.5 GHz。     

一种基于共轭梯度法的频谱分析方法

提出了一种分析频谱的新方法,其主要思想是采用共轭梯度法训练傅里叶基神经网络权值,根据权值获得信号的幅度谱和相位谱,并给出了基于Matlab语言的频谱分析应用实例。仿真结果表明,与FFT相比,该方法具有计算精度高,计算速度快以及滤除噪声的功能。     

基于时域直接正交变换谐波电流检测方法的单相有源电力滤波器研究

瞬时无功理论在三相电路中检测谐波及无功电流的应用较为广泛，本文首先分析了这一理论在单相有源电力滤波系统谐波电流检测中的应用，在此基础上提出了一种将负载电流于时域内直接做正交变换进行电流谐波检测的方法，该方法不需对采样得到的到的电流进行移相，直接在时域内做正交变换得到所需的谐波电流。文章对其进行了理论分析，并在单相并联有源电力滤波系统模型中进行了仿真，重点分析了该方法在负载突变时的动态响应性能。最后文章给出了基于所提出的时域内直接正交变换检测谐波方法的实验结果，验证了该方法能够对谐波电流进行比较理想的补偿。     

一个高效的基于证书数字签名方案

基于证书公钥密码学是Gentry在Eurocrypt 2003上首次提出的,它克服了传统公钥系统中存在的证书管理问题和基于身份公钥系统中存在的密钥托管问题。基于计算性Diffie-Hellman假设,构造一个Shnorr型的高效的基于证书数字签名方案,并在随机预言机模型（Random Oracle Model）下证明其安全性。该方案在签名算法中不需要任何双线性对运算,在签名验证算法中只需要一个双线性对运算,在效率上优于已有的基于证书数字签名方案。     

滤嘴参数对细支烟主流烟气中代表性香味成分释放量的影响

  目的  研究滤嘴参数（滤棒压降、滤嘴通风率）对细支烟香味成分释放的影响。  方法  按单因素设计制备60个卷烟样品,采用CH2Cl2浸提、GC/MS分析测定滤片捕集的代表性香味成分。在此基础上,建立并筛选了滤嘴参数对香味成分释放量的预测模型。  结果  ① 细支烟主流烟气中代表性碱性、中性、酸性和香味成分总释放量与滤棒压降和滤嘴通风率均呈显著负相关;②滤棒压降对细支烟主流烟气香味成分释放量的影响高于常规烟,而滤嘴通风则相反。③外部验证结果显示,4个预测模型的平均预测偏差在4.23%~5.95%之间,所建立的模型预测精度良好。