L频段数字航空通信系统1(L-DACS1)以内嵌方式工作在测距仪(DME)波道间,会产生测距仪信号干扰正交频分复用(OFDM)接收机的问题,针对此提出联合非线性最小二乘法(NLS)与压缩感知(CS)信号重构的测距仪干扰抑制方法(简称联合DME干扰抑制方法...L频段数字航空通信系统1(L-DACS1)以内嵌方式工作在测距仪(DME)波道间,会产生测距仪信号干扰正交频分复用(OFDM)接收机的问题,针对此提出联合非线性最小二乘法(NLS)与压缩感知(CS)信号重构的测距仪干扰抑制方法(简称联合DME干扰抑制方法)。首先,接收机通过非线性最小二乘法重构DME信号,并在时域消除DME信号;然后,通过低通滤波器进一步消除残留DME信号及带外噪声的影响;最后,利用压缩感知方法重构残留DME信号,并转换到频域消除残留的DME信号。仿真结果表明:所提出的联合干扰抑制方法可衰减DME信号功率达45 d B,显著地提高了OFDM系统链路传输可靠性。展开更多
Seven inorganic amendment materials were added into arsenic （As） contaminated soil at a rate of 0.5% （w/w）; the materials used were sepiolite, red mud, iron grit, phosphogypsum, ferrihydrite, iron phosphate, and l...Seven inorganic amendment materials were added into arsenic （As） contaminated soil at a rate of 0.5% （w/w）; the materials used were sepiolite, red mud, iron grit, phosphogypsum, ferrihydrite, iron phosphate, and layered double oxides （LDO）. Plant growth trials using rape （edible rape, Brassia campestris L.） as a bio-indicator are commonly used to assess As bio- availability in soils. In this study, B. campestris was grown in a contaminated soil for 50 days. All of the inorganic amend- ments significantly inhibited the uptake of As by B. campestris. Following soil treatment with the seven aforementioned inorganic ammendments, the As concentrations in the edible parts of B. campestris were reduced by 28.6, 10.5, 8.7, 31.0, 47.4, 25.3, and 28.8%, respectively, as compared with the plants grown in control soil. The most effective amendment was ferdhydrite, which reduced As concentration in B. campestris from 1.84 to 0.97 mg kg-~, compared to control. Furthermore, ferrihydrite-treated soils had a remarkable decrease in both non-specifically sorbed As and available-As by 67 and 20%, respectively, comparing to control. Phosphogypsum was the most cost-effective amendment and it showed excellent performance in reducing the water soluble As in soils by 31% and inhibiting As uptake in B. campestris by 21% comparing to control. Additionally, obvious differences in As transfer rates were observed in the various amendments. The seven amendment materials used in this study all showed potential reduction of As bioavailability and influence on plant growth and other biological processes still need to be further explored in the long term.展开更多
The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers w...The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers were developed for potential small-diameter blood vessel applications. CS is a positively charged polymer which is beneficial for cell attachment and growth,while PLCL provides favorable mechanical support due to its excellent elasticity. Typical nanofibrous structure was observed in both CS/PLCL and pure PLCL scaffolds. The optimal mechanical property could be achieved when the weight ratio of CS/PLCL was 1 ∶ 2.Compared with pure PLCL scaffolds, the CS/PLCL scaffolds showed higher hydrophilicity and markedly promoted the attachment,spreading and proliferation of human umbilical vein endothelial cells( HUVECs). Hence,CS/PLCL scaffolds can be used as potential vascular grafts.展开更多
基金Supported by the Key Research of Southwest University of Science and Technology-"Biologic Stability and Mutation under the Radiate Environment and the Mechanism"(07XJGZB05)Research Foundation of Southwest University of Science and Technology for youth(O8zx315208zx3152)
文摘L频段数字航空通信系统1(L-DACS1)以内嵌方式工作在测距仪(DME)波道间,会产生测距仪信号干扰正交频分复用(OFDM)接收机的问题,针对此提出联合非线性最小二乘法(NLS)与压缩感知(CS)信号重构的测距仪干扰抑制方法(简称联合DME干扰抑制方法)。首先,接收机通过非线性最小二乘法重构DME信号,并在时域消除DME信号;然后,通过低通滤波器进一步消除残留DME信号及带外噪声的影响;最后,利用压缩感知方法重构残留DME信号,并转换到频域消除残留的DME信号。仿真结果表明:所提出的联合干扰抑制方法可衰减DME信号功率达45 d B,显著地提高了OFDM系统链路传输可靠性。
基金the financial support of the National Natural Science Foundation of China (41171255)the National Scientific and Technology Program during 12th Five-Year Plan period, China (2012BAD14B02)
文摘Seven inorganic amendment materials were added into arsenic （As） contaminated soil at a rate of 0.5% （w/w）; the materials used were sepiolite, red mud, iron grit, phosphogypsum, ferrihydrite, iron phosphate, and layered double oxides （LDO）. Plant growth trials using rape （edible rape, Brassia campestris L.） as a bio-indicator are commonly used to assess As bio- availability in soils. In this study, B. campestris was grown in a contaminated soil for 50 days. All of the inorganic amend- ments significantly inhibited the uptake of As by B. campestris. Following soil treatment with the seven aforementioned inorganic ammendments, the As concentrations in the edible parts of B. campestris were reduced by 28.6, 10.5, 8.7, 31.0, 47.4, 25.3, and 28.8%, respectively, as compared with the plants grown in control soil. The most effective amendment was ferdhydrite, which reduced As concentration in B. campestris from 1.84 to 0.97 mg kg-~, compared to control. Furthermore, ferrihydrite-treated soils had a remarkable decrease in both non-specifically sorbed As and available-As by 67 and 20%, respectively, comparing to control. Phosphogypsum was the most cost-effective amendment and it showed excellent performance in reducing the water soluble As in soils by 31% and inhibiting As uptake in B. campestris by 21% comparing to control. Additionally, obvious differences in As transfer rates were observed in the various amendments. The seven amendment materials used in this study all showed potential reduction of As bioavailability and influence on plant growth and other biological processes still need to be further explored in the long term.
基金National Natural Science Foundations of China(Nos.31771048,31570984,31271028)International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality,China(No.15540723400)Biomedical Textile Materials Science and Technology(111 Project),China(No.B07024)
文摘The ideal small-diameter vascular grafts should mimic the nanostructure and mechanical properties of nature blood vessel. In this study, electrospun chitosan( CS)/poly( L-lactic-co-ε-caprolactone)( PLCL) nanofibers were developed for potential small-diameter blood vessel applications. CS is a positively charged polymer which is beneficial for cell attachment and growth,while PLCL provides favorable mechanical support due to its excellent elasticity. Typical nanofibrous structure was observed in both CS/PLCL and pure PLCL scaffolds. The optimal mechanical property could be achieved when the weight ratio of CS/PLCL was 1 ∶ 2.Compared with pure PLCL scaffolds, the CS/PLCL scaffolds showed higher hydrophilicity and markedly promoted the attachment,spreading and proliferation of human umbilical vein endothelial cells( HUVECs). Hence,CS/PLCL scaffolds can be used as potential vascular grafts.
