Removal of Cationic Dye from Aqueous Solution by a Macroporous Hydrophobically Modified Poly(acrylic Acid‐acrylamide) Hydrogel with Enhanced Swelling and Adsorption Properties

A macroporous, hydrophobically modified poly(acrylic acid‐acrylamide) hydrogel was prepared. The fourier transform infrared (FTIR) spectrum and field emission scanning electron microscopy (FE‐SEM) results showed that the hydrogel had a macroporous structure. The dynamic swelling and removal of cationic dyes, crystal violet (CV) and basic magenta (BM), by this macroporous hydrophobically modified poly(acrylic acid‐acrylamide) hydrogel were studied. The adsorption capacity and kinetic and isotherm studies of the cationic dyes into the hydrogels have been evaluated. It was found that the macroporous hydrophobically modified hydrogel (M) exhibited improved swelling and adsorption capacity compared with the non‐macroporous hydrophobically modified hydrogel (NM). The adsorption process agreed very well with the Langmuir model and the adsorption of the cationic dyes depended on the pH of the solution via a mechanism combining swelling, electrostatic, and hydrophobic interactions. Moreover, adsorption kinetic studies showed that the adsorption followed a pseudo‐second‐order kinetic model, indicating that chemical adsorption was the rate‐limiting step.     

中国水资源利用效率驱动效应测度及空间驱动类型分析

综合考虑产业用水效率、产业用水结构、经济水平、水资源禀赋及水资源开发利用率5个因素对中国用水效率的影响,基于扩展的Kaya恒等式建立因素分解模型,应用LMDI分解方法对1997~2008年中国用水效率变化进行分解分析,计算各驱动效应因素的相对贡献率,测度它们的影响程度和方向。结果表明:产业用水效率效应和经济水平效应是影响中国用水效率变化的最显著因素。通过计算各驱动效应的绝对贡献率,采用最小方差法将中国31个行政区(港澳台除外)确定为4种空间驱动类型,进而分析用水效率变化驱动效应的分布特点。研究结果对于正确理解中国用水效率的变化与经济发展之间的关系以及产业结构的调整与可持续发展研究具有一定的参考价值。     

Climate change response to astronomical forcing during the Oligocene-Miocene transition in the equatorial Atlantic (ODP Site 926)

The Oligocene-Miocene transition period was characterized by a decrease in global CO₂ levels, expansion of polar ice sheet, fall in global sea-level, etc. However, the reasons for, and mechanisms of, this global, extreme-cold climate change event (Mi-1) still remain controversial. Our samples from the core of the Ocean Drilling Program (ODP) Leg 154, Site 926, located in the equatorial Atlantic, mainly consist of light-gray, nannofossil chalk with foraminifers interbedded with green-ish-gray, clayey, nannofossil chalk sediments. Color variation from light-gray layers (up to 80% carbonate content) to dark layers (～60% carbonate content) was observed to occur cyclically at the meter scale. Therefore, we chose color reflectance lightness (L*) data as the paleoclimate proxy on which to perform cyclostratigraphic analysis because it could reflect carbonate content changes. Based on the recognition of the 405 kyr long eccentricity and ～40 kyr obliquity cycles of the L* series, we tuned the series to establish an absolute astronomical time scale using the published age of the Oligocene-Miocene boundary (OMB) as the anchor for an absolute age control point. The power spectra of the tuned L* series showed that the long eccentricity signals became significantly weak, while the obliquity signals became strong, from the Late Oligocene to the Early Miocene. The 405 kyr long eccentricity minimum coincided with the 1.2 Myr obliquity node at the OMB, and similar convergences might be closely related to other extreme-cold events in Earth’s history. In addition, the sedimentation accumulation rate, oxygen isotopes of benthonic foraminifers, and rodents’ per-taxon turnover rate from Central Spain showed the same ～2 Myr cyclicity, which indicates the significant influence of Earth-orbital forcing on the Earth system and ecological evolution on the million-year time scale.     

浙江及邻区地震精定位及应用研究

对2006年2月～2010年4月浙江数字地震台网所有记录到的浙江及邻区范围内437个地震事件重新进行震相识别及定位,筛选出震相清晰且有4个台站记录的291个地震事件后,用双差地震定位法进行精确定位,得到多个事件内部相关事件之间的距离.结果表明,重新定位后地震震源的相对位置比常规地震定位方法得到的结果更加精确.此外本文得到了该区域内多个地震序列的精确活动图像,并根据新的定位结果讨论了地震分布、发震与断裂构造的关系,结果显示出较好的一致性.     

Construction of two selectable markers for integrative/conjugative plasmids in Flavobacterium columnare

Flavobacterium columnare, the etiological agent of columnaris disease, is one of the most important and widespread bacterial pathogens of freshwater fish. In this study, we constructed two artificial selectable markers (chloramphenicol and spectinomycin resistance) for gene transfer in F. columnare. These two new artificial selectable markers, which were created by placing the chloramphenicol or spectinomycin resistance gene under the control of the native acs regulatory region of F. columnare, were functional in both F. columnare and Escherichia coli. The integrative/conjugative plasmids constructed by using these markers were introduced into F. columnare G4 via electroporation or conjugation. The integrated plasmid DNA was confirmed by Southern blotting and PCR analysis. These two markers can be employed in future investigations into gene deletion and the pathogenicity of virulence factors in F. columnare.     

Observations of six glitches in PSR B1737−30

Six glitches have been recently observed in the rotational frequency of the young pulsar PSR B1737−30 (J1740−3015) using the 25-m Nanshan telescope of Urumqi Observatory. With a total of 20 glitches in 20 yr, it is one of the most frequently glitching pulsars of the ∼1750 known pulsars. Glitch amplitudes are very variable with fractional increases in rotation rate ranging from 10⁻⁹ to 10⁻⁶. Interglitch intervals are also very variable, but no relationship is observed between interval and the size of the preceding glitch. There is a persistent increase in     , opposite in sign to that expected from slowdown with a positive braking index, which may result from changes in the effective magnetic dipole moment of the star during the glitch.     

岩溶区典型石灰土Cd形态指示意义及风险评价——以桂林毛村为例

为了了解岩溶区石灰土中重金属Cd形态分配特征及富集情况,在桂林毛村采集了3种处于不同发育阶段的黑色、棕色和红色石灰土进行研究。通过原子光谱仪测试了Cd质量分数,运用改进的Tessier分析法测定了3种石灰土中Cd的可交换态(EXC)、碳酸盐结合态(CAB)、铁锰氧化物结合态(OXI)、有机结合态(ORG)、残渣态(RES)5种形态,并对其指示意义及风险进行了分析与评价,结果表明,3种石灰土中Cd质量分数从大到小依次为早期黑色石灰土、中期棕色石灰土、晚期红色石灰土。形态测试结果表明:黑色石灰土和棕色石灰土中Cd形态以铁锰氧化态和残渣态为主,占土壤Cd质量分数的63%以上,且5种形态质量分数从大到小顺序均为铁锰氧化态、残渣态、可交换态、碳酸盐结合态、有机结合态;红色石灰土Cd形态以残渣态为主,占土壤Cd质量分数的76%,形态分配特征从大到小为残渣态、铁锰氧化态、可交换态、碳酸盐结合态、有机结合态。Cd稳定度和富集程度评价结果表明:在黑色石灰土、棕色石灰土和红色石灰土中Cd稳定度逐渐减小,环境二次释放风险逐渐降低;富集程度从大到小依次为黑色石灰土、棕色石灰土、红色石灰土,其中Cd在黑色石灰土中呈显著富集状态,在棕色石灰土中呈中度富集状态,在红色石灰土中呈轻微富集状态。潜在生态风险评价和健康风险评价结果表明,由早期黑色石灰土到中期棕色石灰土和晚期红色石灰土,土壤中Cd的生态风险和健康风险均逐渐降低。研究结果可为岩溶区土壤重金属Cd污染修复与治理提供基础数据。     

三维空间中沙粒旋转对其跃移轨迹的影响

风沙流中沙粒旋转通常具有明显的三维旋转特性。本文通过数值建模考察了三维空间中不同沙粒旋转状态所产生的Magnus力对其跃移运动轨迹特征的影响。在三维坐标系中,X、Y、Z轴分别表示水平、垂直和横向方向,气流沿X方向流动,沙粒起跳时位于XY平面内。结果表明,跃移沙粒仅绕Z轴旋转起跳时,初始起跳角速度的增大会导致在XY平面内的跃移高度和跃移距离减小而降落角增大,但Z方向没有运动发生。跃移沙粒仅绕X轴或Y轴旋转起跳时,绕X轴或Y轴的初始起跳角速度的变化对在XY平面内的跃移轨迹特征量没有显著影响,但沙粒偏离XY平面的偏离距离和偏离角的绝对值随起跳角速度绝对值的增加而增大。因此,沙粒起跳旋转状态对其跃移轨迹有重要的影响。     

使用中国地震台网资料快速测定中强地震矩震级

利用中国地震台网数字地震资料,选取国内Ms≥5.3地震波形数据,采用长周期波形拟合方法,快速计算2008年至今86个中强震的标量地震矩MO和矩震级Mw,并将Mw与GCMT的测定结果及中国地震台网中心测定的面波震级Ms进行对比.结果表明：矩震级与GCMT测定一致,与中国地震台网中心测定的面波震级关系为Mw=0.86Ms＋0.63.     

Observational limits on inverse Compton processes in gamma-ray bursts

Inverse Compton (IC) scattering is one of two viable mechanisms that can produce prompt non-thermal soft gamma-ray emission in gamma-ray bursts. IC requires low-energy seed photons and a population of relativistic electrons that upscatter them. The same electrons will upscatter the gamma-ray photons to even higher energies in the TeV range. Using the current upper limits on the prompt optical emission, we show that under general conservative assumption the IC mechanism suffers from an 'energy crisis'. Namely, IC will overproduce a very high energy component that would carry much more energy than the observed prompt gamma-rays, or alternatively it will require a low-energy seed that is more energetic than the prompt gamma-rays. Our analysis is general, and it makes no assumptions on the specific mechanism that produces the relativistic electron population.