有机杂化硫代锑酸盐化合物[Co（en）3]（Hen）SbS4和[Ni（en）3]2Sb2S5的溶剂热合成及晶体结构

利用溶剂热法合成2种有机杂化硫代锑酸盐化合物[Co(en)3](Hen)SbS4(1)和[Ni(en)3]2Sb2S5(2)(en=乙二胺),它们的结构经IR、元素分析和单晶x-射线衍射表征。1是由孤立四面体[SbS4]3-阴离子、质子化有机胺[Hen]+和配阳离子[Co(en)3]2+组成,而2是由孤立二聚阴离子[Sb2S5]4-和配阳离子[Ni(en)3]2+组成.     

CeO2-TiO2/[CoW12O40]5--HTLC的制备及光催化性能

为了克服杂多酸易溶于极性溶剂,较难回收重复使用的缺点,采用共沉淀法制备了镁铝水滑石;并以硝酸根型水滑石作为前体,通过插层组装合成了杂多阴离子[CoW12O40]5--HTLC;再采用微乳液法将CeO2掺杂的TiO2负载到[CoW12O40]5--HTLC上,焙烧后得到CeO2-TiO2/[CoW12O40]5--HTLC光催化剂。采用XRD、FT-IR、SEM-EDS和UV-Vis漫反射光谱等手段对催化剂进行了表征;以甲基橙为模拟污染物,考察了催化剂样品的光催化性能。实验结果表明:CeO2掺杂TiO2复合粒子在可见光区吸光性能高于TiO2;CeO2掺杂TiO2与杂多阴离子[CoW12O40]5-有协同光催化作用,CeO2-TiO2/[CoW12O40]5--HTLC光催化剂对可见光的吸收大大增强。经模拟日光照射2 h,15%(CeO2-TiO2)/5%[CoW12O40]5--HTLC催化剂对甲基橙的脱色率达到93%。     

新型四帽杂多化合物H11[PMo12O40（VO）4][V2O7]2·3H2O的合成、结构及性能

通过水热法合成了一种新型的四帽杂多化合物H11[PMo12O40(VO)4]·[V2O7]2·3H2O.用红外光谱、X-射线单晶衍射技术对结构进行了表征,并测试了其在苯甲醛氧化制苯甲酸中的催化活性.结果表明,该化合物对苯甲醛选择性氧化制苯甲酸具有较高的催化活性.     

Ai(i-Bu)3-La(AA)3-H2O催化的环氧乙烷聚合作用

详细研究了在Al(i-Bu)3-La(AA)3-H2O的催化下环氧乙烷的均聚反应和与环氧丙烷的共聚反应情况.实验发现在该催化剂的作用下,以甲苯为反应介质,在n[Al(i-Bu)3]∶n[La(AA)3]为16～10,n[Al(i-Bu)3]∶n[H2O]为1∶(1～3),n(单体)∶n[La(AA)3]为1000∶(1～3),n(单体)∶n[Al(i-Bu)3]为100∶(1～3),45℃预聚2h,85～90℃聚合10h的条件下,催化剂的活性高,聚合速率大,所得产物的平均相对分子质量高.以水为溶剂,在30℃测得环氧乙烷均聚物的v=310×104;在m(环氧乙烷)∶m(环氧丙烷)为195∶15时,其共聚物的v=380×104,且产物有较好的水溶性.     

新型二维全无机的多酸化合物Na13H5[Pr(W5O18)2]2·62H2O的合成、晶体结构和荧光性质

在pH值约为6.5的水溶液中,K12[Sb2W22O74(OH)2]·27H2O,PrCl3.7H2O和Na2CO3的反应得到了一个基于[Pr(W5O18)2]9-阴离子和Na+的新型二维全无机的多酸化合物Na13H5[Pr(W5O18)2]2·62H2O.通过单晶X射线衍射、红外光谱、紫外光谱和元素分析对标题化合物的结构进行了表征,并且对标题化合物的荧光性质进行了测试.     

由[khuo4A][haη5][ha3]谈连城莲峰话的被动与使动

连城县莲峰镇的[khuo4A]可以当使动动词以及被动标记,其语法功能与其他客家话的"分"相同。[khuo4A]的这种形式在客家话中是很特别的,目前不见于连城县以外的客家话。它运用在使动句时,往往可与[haη5]或[ha3]互换而句意相同。不过[khuo4A]与[haη5]或[ha3]也有不能互换的时候,有时只能使用[haη5]或[ha3],有时却只使用[khuo4A],显见三者的关系并不完全对等,使用上有竞争关系。[haη5]及[ha3]都是较新的表达形式,但这究竟是普及的现象或是个别情况,尚待进一步的调查。     

机械合金化-热处理制备V5Si3材料

[目的]为了获得V/Si类化合物基本结构和性能,拟合成V/Si系金属间化合物V_5Si_3。[方法]采用V粉和Si粉作原料,按照原子比V∶Si=5∶3进行称量,通过机械合金化与热处理制备V_5Si_3,再利用XRD,SEM/EDS等方法对球磨粉体试样和热处理试样的物相组成、微观形貌和微区成分进行分析与表征,并测量其抗压性能和硬度。[结果]V/Si粉体经过球磨后颗粒度减小,逐渐非晶化,最终得到以原子比V∶Si=5∶3结合的非晶态物质;经过热处理,非晶态结构转变为V_5Si_3晶体。[结论]随着热处理温度的升高,晶体结晶度提高,材料的抗压强度和显微硬度增加,抗压强度达到640 MPa,显微硬度最高为656 MPa。     

有机-无机复合物[Zn(C10H8N2)3][HPMo12O40（VO）2]的合成、晶体结构及性能研究

通过水热法合成了一种新型的有机-无机复合物[Zn(C10H8N2)3][HPMo12O40(VO)2],用X-射线单晶衍射技术及红外光谱对其结构进行了表征,并探讨了该复合物在仲辛醇选择性氧化制己酸中的催化活性.实验结果表明,该复合物是由1个金属有机配离子[Zn(C10H8N2)3]2+和1个多金属氧酸阴离子[HPMo12O40(VO)2]2-构成的,二者之间通过静电引力结合,该复合物对仲辛醇氧化制己酸具有较高的催化活性.     

一种基于同多钼酸盐支撑化合物{[Zn（phen）2]2(γ-Mo8O26)}的合成及其结构表征

本文采用非水热法合成了一个基于同多钼酸盐支撑的化合物{[Zn(phen)2]2(γ-Mo8O26)}(phen=1,10-phenanthroline),并采用红外光谱、热重分析以及单晶X射线衍射等方法对此化合物进行了表征。结果表明,目标化合物{[Zn(phen)2]2(γ-Mo8O26)}中包含一个[γ-Mo8O26]4-阴离子基团与两个[Zn(phen)2]2+配位单元;该化合物通过C-H...O氢键把phen和[γ-Mo8O26]4-阴离子紧紧连接起来,形成了一个三维的超分子结构。     

组合数丢番图方程[2x]=[4y]的正解

运用递推序列法，给出组合数丢番图方程[x2]=[y4]的一个初等解法．     

Abrupt climate change of EastAsian Monsoon at 130 kaBP inferred from a high resolu-tion stalagmite δ18O record

^230Th ages and oxygen isotope data of a stalagmite from Shanbao Cave in Hubei Province characterize the East Asian Monsoon precipitation from 133 to 127ka. The decadal-scale high-resolution δ^18O record reveals a detailed transitional process from the Penultimate Glaciation to the Last Interglaciation. As established with ^230Th dates, the age of the Termination Ⅱ is determined to be 129.5±1.0 kaBP, which supports the Northern Hemisphere insolation as the triggers for the ice-age cycles. In our δ^18O record, the glacial/interglacial fluctuation reaches about 4‰, almost the same level as in other Asian Monsoon cave stalagmite δ^18O records. The transition of the glacial/interglacial period in our record can be recognized as four stepwise stages, among which, a rapid rise of monsoon precipitation follows the stage of “Termination Ⅱ pause”. The rapid rise is synchronous with the abrupt change of global methane concentration, which reflects that an increase in both Asian Monsoon precipitation and tropical wetland plays an important role in the global climate changes.     

Orbital- and millennial-scale variability of the Asian monsoon during MIS8 from Sanbao Cave at Mount Shennongjia,central China

One stalagmite oxygen isotope record from Sanbao Cave, China, established with 7 230Th ages and 355 oxygen isotope data, pro- vides a continuous history of the East Asian Monsoon (EAM) intensity for the period from 284 to 240 thousand years before present (ka BP) with typical errors of 3―4 ka. This new record extends the previously published stalagmite δ18O record back to the marine oxygen isotope stage (MIS) 8. The MIS8 EAM record broadly follows orbitally-induced insolation variations and is punctuated by...     

川东北宋家洞石笋氧碳同位素及锶含量突变分析

通过对宋家洞石笋SJ3的氧碳同位素及锶含量进行Mann-Kendall test突变分析,得出以下结论:(1)氧同位素值记录了末次冰盛期向Heinrich Event 1时期的转变;(2)碳同位素值和锶含量记录了由H1冷期向BФlling-AllerФd暖期的转变;(3)碳同位素值和锶含量指示了在19.8～15.3ka时当地的东亚夏季风和冬季风呈正相关关系,在15.3～14.8 ka呈负相关关系,表明石笋SJ3记录了古气候环境的冷干、暖湿变化,且不同气候指标对环境变化的敏感度不同。     

The δ18O variation of a stalagmite from Qixing Cave, Guizhou Province and indicated climate change during the Holocene

A stalagmite from Qixing Cave, Guizhou Province was dated with the TIMS U-series method and its oxygen isotope composition was analyzed. On the basis of the ages and the variations of the δ¹⁸O of the stalagmite, the climate change of the last 7.7 ka has been reconstructed in this area: 7.7–5.8 ka, summer monsoon maximum period; 5.8–3.8 ka summer monsoon weakening period; 3.8–0.15 ka, weakened summer monsoon and high amplitude climate fluctuations period. We put forward that the increasing trend of δ¹⁸O of the stalagmite reflected not only the weakening of the summer monsoon, which was caused by the decreasing of solar radiation in the Northern Hemisphere, but also the possibly decreasing contribution of the southwest monsoon to the rainfall of this area. These results are consistent with the output of the numerical climate-model modeling. The high amplitude fluctuation of the δ¹⁸O may imply the quick shift of the contributions of different moisture sources to the precipitation in this area.     

Pollen evidence from Baode of the northern Loess Plateau of China and strong East Asian summer monsoons during the Early Pliocene

The red clay eolian sequence on the Chinese Loess Plateau (CLP) is an important archive for paleoclimate change from the late Miocene to Pliocene,and can provide significant information for the controversial problems of East Asian monsoon evolution and its forcing mechanism.In this study,we present a pollen record from Baode,northern CLP.The record shows four stages of paleoecological evolution.From 5.6-4.4 Ma,a forest steppe ecosystem developed under an extremely warm period with high seasonal precipitation.Since 4.4 Ma,a drier episode occurred,which prompted parkland landscapes to develop.During 3.5-3.05 Ma,the environment changed to a rather open steppe ecosystem with a much cooler and drier climate.After 3.05 Ma,the vegetation evolved to forest steppe.Using the percentages of arboreal plants to mirror precipitation,and comparing with other published pollen data from the CLP,we find the existence of S-N directionality of the precipitation change and high percentage of arboreal plants in the entire CLP during the Early Pliocene,which suggest the CLP was characterized by a strong East Asian summer monsoon.The strong summer monsoon corresponds well to the low global ice volume,which may illuminate global climate mechanism for the summer monsoon evolution in the early Pliocene.     

Effect of precession on the Asian summer monsoon evolution: A systematic review

Geological climatic records and model simulations on the Asian summer monsoon climate change induced by insolation forcing of the Earth＇s precession are systematically reviewed in this paper. The presentation of the questions on the mechanism of the Asian monsoon evolution at the precession band, currently existing debates and future research directions are discussed. Since the early 1980s, more and more observed evidence and simulated results, especially the absolute-dated stalagmite records and orbital-scale transient model runs in the last few years, have indicated that the quasi-20ka period in the Quaternary monsoon climate change is caused by precession. However, debates still exist on the dynamic mechanism how precession affects the Asian monsoon. The ＂zero phase＂ hypothesis says that the Asian monsoon is merely controlled by summer insolation in the Northern Hemisphere （NH） while the ＂latent heat＂ hypothesis emphasizes the dominant effect of latent heat transport from the Southern Hemisphere （SH） besides the role of the northern insolation. The two hypotheses have separately been supported by some evidence. Although we are cognizant of the importance of northern solar radiation and the remote effect of southern insolation, it has still a long way to go before comprehensively understanding the evolutionary mechanism of the Asian monsoon. In view of the problems existing in present researches of monsoon-dominated climate change at the precession scale, we propose that studies on the environmental significance of geological monsoon proxies, feedback processes in the long-term transient simulations and intercomparisons between observations and modeling results should be strengthened in the future.     

三门峡王官与武威沙沟黄土记录中的末次间冰期向末次冰期转换期的暖性回返事件

河南三门峡王官剖面与甘肃武威沙沟剖面捕捉到了末次间冰期向末次冰期转换时期发生于72 ka前后持续时间约为2 ka的一暖性回返事件,两剖面的冬、夏季风替代指标对该暖性回返事件的反应在时间上大致同步(其时间段约为71～73 ka,在71.4～72.1 ka前后该暖性回返事件最强盛),暗示该暖性回返事件在东亚季风区可能是一普遍存在的气候突变事件.鉴于该暖性回返事件在全球其他地区的海洋、陆地、冰芯记录中也有较普遍的反映,我们认为该事件很可能是一次发生于气候转型期的全球普遍存在的暖性突变事件.     

Stalagmite-inferred Holocene precipitation in northern Guizhou Province,China, and asynchronous termination of the Climatic Optimum in the Asian monsoon territory

An absolute-dated, bi-decadal-resolution, stalagmite oxygen-isotopic time series from Shigao Cave reveals the evolution of summer monsoon precipitation over the past 9.9 ka BP in northern Guizhou Province, Southwest China. The  18O-inferred climate conditions are divisible into three distinct stages: (1) a maximum humid era from 9.9-6.6 ka BP; (2) a gradual declining precipitation interval between 6.6-1.6 ka BP; and (3) a relatively low precipitation time window after 1.6 ka BP. Consistency of contemporaneous stalagmite Holocene 18O records between Shigao and other caves in the Indian and East Asian monsoon realms support the effect of primary orbital solar forcings on monsoonal precipitation. However, statistical analysis shows a significant spatial asynchroneity of the Holocene Optimum termination in the Asian monsoon territory. The Holocene Optimum ended at 7.2-7.4 ka BP in Oman, located in the Indian monsoon region, and at 5.6-5.8 ka BP in Central China, in the East Asian monsoon zone. In Southwest China, the termination occurred between these periods, at 6.6-7.0 ka BP, and was influenced by both monsoon systems. We propose that this spatially asynchronous ending of Holocene Optimum in Asia may be attributed to sea surface temperature changes in the western tropical Pacific, which is a primary moisture source for the East Asian monsoon.     

贵州荔波42.0kaB.P.~65.0kaB.P.气候变化的石笋记录

对贵州荔波董哥洞D42石笋进行TIMS-U测年和碳、氧同位素分析,建立末次冰期42．0ka B．P．～65．0ka B．P．的古气候变化时间序列。研究结果表明,荔波地区在65．0ka B．P．～42．0ka B．P．石笋记录的冷暖事件所反映出的季风气候变化,大致可分为3个气候阶段;65．0ka B．P．～60．6ka B．P．相当于海洋氧同位素MIS4晚期,反映本阶段东亚冬季风强盛,气温降低,表现为干旱寒冷的气候环境;60．6ka B．P．～48．4ka B．P．相当于海洋氧同位素MIS3早期,反映东亚夏季风相对增强,气温升高,有效降水相对较少,表现为温暖半干旱的气候环境;48．4ka B．P．～42．0ka B．P．相当于海洋氧同位素MIS3中期,显示东亚夏季风由强变弱,东亚冬季风相对增强,表现为干旱冷凉的气候环境。石笋记录揭示的2次寒冷事件在各类沉积物中均有记录,反映为全球变化的气候事件,相当于北大西洋沉积物中的Heinrich5和Heinrich 6冷事件,可以进行全球对比,显示荔波地区与北极地区存在着古气候的遥相关。     

Weathering Signals of Millennial-Scale Oscillations of the East-Asian Summer Monsoon over the Last 220 ka

This study generated a high-resolution paleoweathering record of the loess-soil sequence from the central Loess Plateau covering the last 220 ka using the ratio between the CBD (citrate-bicarbonate-dithionite) extractable free Fe_2O_3 (Fed) and total Fe_2O_3 (Fet). The new proxy shows a series of millennial oscillations, which are not necessarily documented by magnetic susceptibility from the same site. Because chemical weathering in the region depends mainly upon summer precipitation and temperature, we interpret these changes to be a result of millennial-scale variations in the strength of the East-Asian summer monsoon. Over the last glacial period, there is general agreement between the loess weathering record and the GRIP ice δ~(18)O record. The first suggests a rather stable summer monsoon pattern during the Last Interglacial period (marine δ~(18)O stage 5e). Large amplitude millennial oscillations of the summer monsoon seem to be particularly characteristic of the last glacial period whereas the fluctuations for the older periods are smoother.