简论21世纪初美国中东战略中的美国-伊朗关系

美国对伊朗战略是美国中东战略的重要组成部分。伊朗的政治、经济、社会体制的变化将引起中东政治格局的重大变化。9.11事件以后,美国中东战略的焦点转变为“反恐”:军事上以打击恐怖主义组织和活动、占领中东的战略要地为目标,在中东大力传播美国的“民主、人权”意识,在重建伊拉克、阿富汗、推进中东和平路线图的口号下“改造中东”,经济上控制中东的石油天然气资源,扩张美国在中东的市场,实施“美国-中东自由贸易区”构想,弱化中东和平进程的意义,千方百计使美国的国家利益最大化。美国-伊朗关系,始终围绕着两国国家利益这一核心展开。本文简略地分析了21世纪初期以来美国-伊朗关系的特征及其变化、影响当今美国-伊朗关系的重大障碍,预测了美国的伊朗政策走势,结论是:21世纪初期美国-伊朗关系根本改善的可能性不大。     

利用南山数据对PSR B0329+54的长时标轮廓稳定性的研究

利用新疆天文台25 m射电望远镜2003—2009年对PSR B0329+54长达453 h的观测数据,研究了这颗源在1540 MHz上正常模式和反常模式的轮廓稳定性时标.通过不同时间的积分脉冲轮廓与参考轮廓交叉相关系数分析,发现随积分时间的增加,两种模式的轮廓先是以较快的速度趋于稳定,在积分时间增加到约(4±1) min时,轮廓趋稳速率放缓,当积分时间达到(140±60) min (正常模式)或达到(65±15) min (反常模式)时,轮廓趋稳速度再次变快.相关系数的结果显示两种模式的轮廓在绝大多数积分时标上都不是完全随机的涨落.如果以发生轮廓趋稳速率从快到慢转变所需的积分时间作为轮廓稳定时标的判据,两种模式的稳定时标均大约为5 min.轮廓中不同成分强度比例的涨落随积分时间的变化关系各不相同,由此可以推断3个成分强度涨落性质有差异.造成轮廓趋稳行为在不同时标上有明显差异的原因有观测噪声和星际闪烁等.     

内蒙古海拉尔北部八大关地区花岗岩的成岩时代、地球化学特征与成因

内蒙古海拉尔北部八大关地区花岗岩以正长花岗岩和二长花岗岩为主,锆石U Pb定年显示其形成于晚三叠世((212±17)~(2267±16) Ma)。岩石为弱过铝质(A/CNK=101~110),分异指数(DI)介于925~958之间。岩石大离子亲石元素K和Rb以及LREE相对富集,高场强元素Nb、Ta、P、Ti 和Ba、Sr相对亏损,并显示中等铕负异常(δEu=051~071)。较低的10 000 Ga/Al值(平均191)以及较低的锆石饱和温度(平均683 ℃)等特征显示该花岗岩属于高分异Ⅰ型。锆石的εHf(t)值较高(450～1045),Hf二阶段模式年龄为059～097 Ga,反映其源区物质为新元古代增生的基性地壳。综合区域其他地质研究成果,认为研究区晚三叠世花岗岩形成于蒙古—鄂霍茨克洋板块俯冲的活动大陆边缘环境。     

THE IDEOLOGY OF EMPIRE IN NATIONAL GEOGRAPHIC MAGAZINE'S COVERAGE OF THE PHILIPPINES, 1898–1908

ABSTRACT. Between 1898 and 1908 the National Geographic Magazine reported copiously on the territorial acquisition and U.S. colonial administration of the Philippines after the Spanish-American War. The pages of the magazine provide an intriguing window on connections between the emergence of geography as an organized profession and the expanding sphere of U.S. control of overseas territories. The overall picture reveals a shift from bold calls for direct economic exploitation of the natural resources and labor power of the Philippine Islands to more platitudinous justifications for U.S. control, based on moral responsibility and the ostensibly objective imperatives of “scientific” development.     

不同潮时对厦门湾水体中234Th/238U不平衡的影响

厦门海水体中^234Th/^238U不平衡的时间序列数据表明，无论是溶解态、颗粒态^234Th还是总^234Th,相对于母体^238U均严重亏损，呈现出与开阔大洋水明显不同的特征。溶解态、颗粒态^234Th的停留时间介于0．5－41d之间，其中低潮时停留时间比高潮时小2－4倍，证实近岸海域具有强烈的清除、迁出作用，且潮汐变化对海域颗粒动力学特征有重要影响。^234Th停留时间与总悬浮颗粒物浓度（TSM）、Ch1.α的关系则表明，近岸海域元素的清除、迁出作用主要受陆源颗粒物输送的影响，与生物活动关系并不密切。此外，非稳态与稳态清除模型结果的对比证明，稳态模型对于具有强烈清除、迁出作用的近岸海域是适用的。     

Improvement of mono-window algorithm for retrieving land surface temperature from HJ-1B satellite data

The thermal infrared channel (IRS4) of HJ-1B satellite obtains view zenith angles (VZA) up to ±33°. The view angle should be taken into account when retrieving land surface temperature (LST) from IRS4 data. This study aims at improving the mono-window algorithm for retrieving LST from IRS4 data. Based on atmospheric radiative transfer simulations,a model for correcting the VZA effects on atmospheric transmittance is proposed. In addition,a generalized model for calculating the effective mean atmospheric temperature is developed. Validation with the simulated dataset based on standard atmospheric profiles reveals that the improved mono-window algorithm for IRS4 obtains high accuracy for LST retrieval,with the mean absolute error (MAE) and root mean square error (RMSE) being 1.0 K and 1.1 K,respectively. Numerical experiment with the radiosonde profile acquired in Beijing in winter demonstrates that the improved mono-window algorithm exhibits excellent ability for LST retrieval,with MAE and RMSE being 0.6 K and 0.6 K,respectively. Further application in Qinghai Lake and comparison with the Moderate-Resolution Imaging Spectroradiometer (MODIS) LST product suggest that the improved mono-window algorithm is applicable and feasible in actual conditions.     

Giant radio pulses from the millisecond pulsar PSR B1937+21 at 327 MHz

Seven giant radio pulses were recorded from the millisecond pulsar PSR B1937+21 during ≈8.1 min observation by the Ooty Radio Telescope (ORT) at 326.5 MHz. Although sparse, these observations support most of the giant pulse behaviour reported at higher radio frequencies (430 to 2380 MHz). Within the main component of the integrated profile, they are emitted only in a narrow (≲47 μs) window of pulse phase, close to its peak. This has important implications for doing super-high precision timing of PSR B1937+21 at low radio frequencies.     

Climate spatial variability and data resolution in a semi-arid watershed, south-eastern Arizona

In the 10,000 km² San Pedro River watershed area in south-eastern Arizona, high-resolution spatial patterns of long-term precipitation and temperature were better reproduced by kriging climate data with elevation as external drift (KED) than by multiple linear regression on station location and elevation as judged by the spatial distribution of interpolation error. Mean errors were similar overall, and interpolation accuracy for both methods increased with increasing correlation between climate variables and elevation. Uncertainty in station locations had negligible effect on mean estimation error, although error for individual stations varied as much as 27%. Our future ability to examine spatial aspects of climate change at high spatial resolution will be severely limited by continuing closures of climate stations in this part of the United States.     

细胞色素B基因PCR-RFLP鉴定阿胶原料

用细胞色素B基因PCR-RFLP方法对阿胶原料进行鉴定。提取马、牛、驴3种动物干皮DNA,PCR扩增细胞色素B基因保守区域的359 bp片段,用限制性内切酶HinfⅠ和HaeⅢ酶切,采用琼脂糖凝胶电泳获得了DNA指纹图谱,根据获得的DNA指纹图谱判定样品所属物种。该方法不仅简便,还可以100%准确鉴定阿胶原料皮样所属物种来源,适合作为常规技术应用于阿胶原料鉴定。