Assessment of the temporal trend of the exposure of people to electromagnetic fields produced by base stations for mobile telephones

Monitoring of electric field levels produced by base stations (BSs) for mobile telephones of different typologies (TACS. GSM, DCS) has been carried out. Results show that BSs can be classified as 'business' or 'residential'. The mean value of six minutes averaged E-field value measured between 10 a.m. and 1 p.m. corresponds to the 84% of the maximum daily six minutes averaged value. Comparison between electromagnetic field levels produced by BSs and their phone traffic data, supplied by companies, is shown. Finally, on an hourly average basis, a daily curve has been constructed of the exposure trend produced by such installations.     

An X-band acousto-optic variable delay line for radar targetsimulation

The design and characterization of a 54-μs, continuously-variable, acousto-optic (AO) delay line developed for radar testing applications is presented. Design goals for the delay line include over 10 MHz of instantaneous bandwidth, 1.2 GHz of tunable bandwidth operating at X-band, 45 dB of dynamic range, and electronically-controllable delay selection to simulate dynamic radar targets with radial range rates up to 500 m/s. In addition, the device was designed to have phase noise and spurious signal levels compatible with high performance radars. To achieve these goals, a 33-MHz center frequency variable delay line was constructed and coherent frequency translation was used to provide operation at S-band. Operating principles for this new intermediate frequency (IF) delay line are presented, and key component issues are discussed. A computer design and analysis tool is described that predicts delay line performance. Experimental results are presented at both the IF and at X-band     

Radiometers, autocorrelators, and matched-filter receivers by means of acousto-optic spectrum analysis

Acousto-optic spectrum analyzers provide a convenient means of separating wide-bandwidth signals into their frequency components. By a change in the rf input signal into the spectrum analyzer and by the provision of additional digital postprocessing, it is possible to perform radiometry, signal autocorrelation, and matched-filter reception. Although the acousto-optic device has a space-integrating architecture, the matched-filter receiver can be implemented for signals having time durations much longer than the acousto-optic cell. The resulting signal-to-noise ratio improvements from the receiver are consistent with the time-bandwidth product of the waveform, rather than the time-bandwidth product of the acousto-optic device. A mathematical foundation of the processor is presented along with specific receiver implementations. Computer-simulation and experimental results demonstrate key findings. In one experimental example, a linear-frequency-modulated waveform is matched-filter processed to recover a signal that is -24 dB with respect to the input noise floor.     

Towards (dis)continuity of agricultural wetlands: Latvia’s polder landscapes after Soviet productivism

The concepts of agricultural regimes in advanced economies, such as productivism or non/neo/post-productivism, have been critically debated over the last decades to understand the transition and diversity of modern agriculture. We explore these concepts to understand the environmentally vulnerable landscape of agricultural wetlands in Latvia that, during the era of Soviet high modernism (productivist agricultural regime), have been converted into polders as part of a mass drainage movement. Today, these post-Soviet agro-polders can be characterised as antipodes in relation to integrity of heritage, ecology and the socio-economics of agricultural concerns. Building on case studies, wider political contexts and current debates on agricultural transitions, the paper traces the transition of wetlands through agricultural regimes and unfolds the various pathways for current polder landscapes. This paper concludes with critical notes on the contemporary co-existence of different agro-polder use of which the most incoherent are the non-productivist actions producing landscapes of mere agricultural appearance.     

Nanocomposites of sodium alginate biopolymer and CdTe/ZnS quantum dots for fluorescent determination of amantadine

A type of novel nanocomposite was successfully synthesized by embedding glutathione capped CdTe/ZnS QDs into sodium alginate biopolymer. The prepared nanocomposite was characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Fourier transform infrared (FT-IR), fluorescence, and UV–vis spectroscopy. When the obtained nanocomposite interacted with amantadine, its fluorescence intensity was effectively quenched. Under the optimized conditions, the as-prepared nanocomposite provided an efficient platform for detection of amantadine drug within a linear range of 3.1–27.9 × 10^?6 mol/L with a detection limit of 0.09 × 10^?6 mol/L. Because of the satisfactory results for amantadine determination in real samples, it is confirmed that the synthesized nanocomposite is attractive and reliable for use in biological detection and related fields.     

Drug release study by a novel thermo sensitive nanogel based on salep modified graphene oxide

To develop more effective drug delivery systems, a novel thermo sensitive nanogels (TNGs) were prepared by crosslinking of NIPAM graft copolymerization onto salep modified graphene oxide (SMGO). The sizes of as-synthesized TNGs were about 93 nm. It was found that the concentration of GO, surfactant, and polymerization agent were strongly effected on the average size of TNGs. Besides, obtained TNGs display thermo-induced transmittance due to thermo-responsive PNIPAM contained in synthesized TNGs. Moreover, the TNGs presented high drug loading capacity and excellent drug release at higher temperate, without any burst release. It was also demonstrated that the loading drug onto TNGs greatly decreased the cytotoxicity of the drug onto HeLa cells. The results offered evidence that SMGO-based TNGs can serve as novel nanocarriers for anti-cancer drug delivery.     

基于因子分析的无花果引进品种果实品质性状综合评价

建立5 个无花果品种的果实品质综合评价体系,为筛选优良品种提供依据。以山东引进的‘布兰瑞克’、 ‘丰产黄’、‘日本紫果’、‘美丽亚’和‘波姬红’5 个无花果品种为试材,测定其4 项外观指标和10 项内在营 养品质指标,对14 项指标进行相关性分析和因子分析,建立基于因子分析的综合品质评价模型,并根据综合品质 得分进行优良度排序。结果表明：5 个无花果品种14 项果实品质性状变异程度不同,其中VC含量间的差异最大, 单果质量、可滴定酸含量、糖酸比、固酸比和镁含量间的差异均中等,其余指标间的差异均相对较小,且品质指 标间均存在不同的相关性。经因子分析提取出3 个特征根大于1的公因子,累计方差贡献率为93.486%,其中第1公 因子的贡献率为47.242%,包含单果质量、果实纵径、可滴定酸含量、可溶性糖含量与可滴定酸含量比、可溶性固 形物含量与可滴定酸含量比、铁、镁和钙含量8 个指标;第2公因子的贡献率为27.150%,包含果实横径、果形指数 和VC含量3 个指标;第3公因子的贡献率为19.094%,包含可溶性糖含量、可溶性固形物含量和钾3 个指标。经综合 品质评价模型得出,5 个无花果品种果实综合品质得分的优良度排序依次为‘布兰瑞克’、‘美丽亚’、‘日本紫 果’、‘波姬红’和‘丰产黄’。     

乌宗布拉克金矿床地质特征及成矿条件分析

介绍了乌宗布拉克金矿床的地质概况:大地构造位置、矿区地质特征、矿体特征、围岩、矿石质量等,并为以后的找矿工作提出了合理的建议。通过野外考察及室内分析,得出了如下主要结论:大地构造位置上处于成矿有利地段,该金矿属于断裂破碎带有关的含金石英脉型及蚀变岩型金矿,金矿脉主要产于石英脉中,并受北西向次级断裂破碎带控制。矿体为脉状、透镜状,具一定的规模,连续性好,属稳定矿体,矿石品位变化不大。通过采样可知,4个金矿体中,L4号金矿体资源量可大幅度增加,具有很好的资源前景,其余3个矿体为非矿体。