段状玉米秸秆阴燃特性试验研究

以北方高寒地区玉米秸秆为研究对象，利用正交设计的试验方法，选取颗粒尺寸、堆积尺寸、堆积密度以及含水率为影响因素，在自制的阴燃试验台进行北方高寒地区玉米段状秸秆的阴燃特性的研究.研究表明：秸秆尺寸350 mm、堆积尺寸250 mm×350 mm×300 mm、堆积密度40 kg/m3、含水率20%时，炉腔内温度高、阴燃时间最长，最高平均温度为701.6℃，阴燃时间为145 min；阴燃时阴燃波自上而下，温度的变化自上向下逐渐升高，属于正向阴燃.     

冬日养生全攻略

冬至是一个非常熏要的节气，这一天是北半球全年中白天最短、夜晚最长的一天；中国北方大部分地区在这一天还有吃饺予、南方吃汤圆的习俗，谚语：冬至到，吃水饺。     

北方农牧交错带景观生态风险评价及格局优化研究

以北方农牧交错带景观生态风险为出发点,基于土地利用、土壤类型、DEM数据、道路、居民点等数据,运用ArcGIS空间分析技术,采用空间主成分分析法、加权叠加分析,得到北方农牧交错带景观生态风险空间分布图,并应用最小累积阻力模型构建生态廊道以优化生态网络结构.结果表明:北方农牧交错带低、较低、中、较高、高风险区的占比分别为0.07%,16.54%,64.32%,19.05%,0.02%;低、较低景观生态风险区主要位于农牧交错带东北段大部分区域、西北段局部区域;较高、高生态风险区主要位于农牧交错带的华北段和西北段部分.研究选取29个生态源地,构建51条生态廊道,识别出34个生态节点,形成"点-线-面"多层次生态网络优化格局.在今后的建设中,应强化生态源地的保护、加强生态廊道和生态节点的建设,以形成稳定的、物种丰富的生态系统.     

亚洲风尘物源研究的新进展

中国北方以及临近蒙古国的亚洲内陆干旱区是全球重要风尘释放中心之一. 中国北方风成黄土与北太平洋软泥和格陵兰冰芯中的亚洲风尘沉积一起, 是研究古环境的良好材料. 粉尘释放后随大气环流向东或东南方向传输, 并常表现为东亚地区春季的沙尘暴. 亚洲风尘还影响着全球水循环和能量平衡. 风尘在风化溶解时不但吸收大量大气二氧化碳, 还是海陆生态系统中铁和磷等营养元素的重要来源, 成为全球物质循环中重要的一部分. 亚洲风尘物源研究对揭示风尘物质的产生与搬运机制、解读风尘沉积的古环境记录、预测风尘的环境效应及指导当代沙尘治理都有重要意义.     

上海本地人源流主成分分析

本文对分布于上海市郊9个区县13个乡镇的本地人群的体质特征和姓氏进行了主成分分析，发现上海本地人主要可以分为3个类群，与其他研究结果相整合推测他们可能分别源于越人、吴人和历史上的北方移民．各主成分所占数据信息的比例显示，本地人中最主要的差异是北方移民和南方土著的差异，其次是南方土著中吴人和越人的差异，再次是越人内部也可以分出两种来源，把各主成分值在上海地图上分别画成趋势图，发现各趋势图分别代表了上海历史上不同的移民事件．对姓氏的地理分析也揭示了南方姓氏和北方姓氏的扩散趋势和性质是不同的。     

关于匈奴人种问题的几点认识

“中国北方长城地带”青铜时代居民的人类学资料表明。匈奴人的人种构成具有突出的地域性，不同地区的匈奴人基本延续了较早时期的人种类型。“中国北方长城地带”东周时期南下的牧人在人种类型上属于“古蒙古高原类型”，来源上应与蒙古高原以及外贝加尔石板墓的居民有一定的渊源关系。到战国晚期以后，当长城以北强大的匈奴联盟形成的时候，这部分古代居民很有可能最终加入到了匈奴联盟当中。     

浙江电信:抓好信息化应用助推新农村建设

党中央、国务院作出的全面“建设社会主义新农村”重大战略决策,犹如一股暖暖的春风吹遍中华大地.从东海之滨到雪域高原,从南国水乡到北方草原,举国上下,各行各业纷纷掀起了社会主义新农村建设的热潮。     

The long-term denudation rate of granitic regolith in Qinhuangdao,North China determined from the in situ depth profile of the cosmogenic nuclides 26Al and 10Be

This study quantifies the surface denudation rate of granitic regolith via the application of the in situ cosmogenic ^26Al and ^10Be depth profile in China. The concentration ranges of ^26Al and ^10Be in the quartz along the -3-m granitic regolith profile in Qinhuangdao are （4.9-23.1） × 10^5 and （2.3-36.6）×10^4 atoms/g, respectively. With the exception of the surface sample, both ^26Al and ^10Be concentrations decrease exponentially with sample depth. The Chi-square best-fitting results revealed a total denudation rate of -9 m/Ma averaged over a 103-105 a timescale, which is lower than the values observed in global granitic outcrops. Compared with global datasets, the flat terrain due to the lack of tectonic activities is most likely the dominant factor that controls the local denudation process. The surface sample offsets from the theoretical cosmogenic nuclide distribution implies that the denudation rate from river basin sediment could be overestimated because of the bioturbation in the surficial soil layer.     

U-Pb ages and Hf isotopes for detrital zircons from quartzite in the Paleoproterozoic Songshan Group on the southwestern margin of the North China Craton

In situ U-Pb dating and Lu-Hf isotopic analysis were carried out for detrital zircons from quartzite in the Paleoproterozoic Songshan Group on the southern margin of the North China Craton （NCC）. The results provide further constraints on the crustal formation and evolution history of NCC. Four ^207Pb/^206Pb age populations were obtained from 99 analyses, with clusters at -3.40 Ga, 2.77-2.80 Ga, -2.50 Ga and 2.34 Ga, respectively. The 3.40 Ga old zircons have similar Hf isotopic compositions to those from Archean rocks in the Jidong and Anshan areas of NCC. However, crustal remnants older than 3.6 Ga have been identified in the southern margin of NCC, the South China Craton, the northwestern part of the Qinling Orogen and its adjacent area. Thus, it is not easy to trace the source rock from which the 3.40 Ge detrital zircons were derived. It can be inferred that the crustal remnants older than 3.40 Ga might have been widely distributed in the North China Craton. The 2.77-2.80 Ga zircons make up a relatively small proportion and have the highest εHf（t） values （up to 6.1±1.6）, consistent with the Hf isotopic composition of the depleted mantle at 2.83 Ga. Their single-stage Hf model age of 2.83 Ga is close to their crystallized age, suggesting that their source rocks were extracted from the contemporaneous depleted mantle. The -2.50 Ga zircon grains constitute about 85% of the total grain population and their Hf isotopic compositions indicate major growth of juvenile crust at -2.50 Ga but minor reworking of ancient crust. The youngest zircon dated in this study gave an U-Pb age of 2337±2.3 Ma, which can be considered the maximum depositional age of the formation of the Songshan Group.