A venomous arthropod in the Early Cambrian Sea

A number of recently evolved animals possess poison glands for feeding and/or defense.However,examples of such animals are rare in the fossil record.We report a fossil arthropod Isoxys curvirostratus from the Early Cambrian Chengjiang biota of China.This species is regarded as the oldest known venomous arthropod based on the presence of venomous glands in its head region.The adult animal is 2-5 cm long and the body is covered entirely with a carapace.The presence of large stalk eyes and a pair of stout grasping appendages with a terminal spine suggest it was raptorial.Interestingly,the two pear-shaped,three-dimensionally preserved objects that are present in the head region and at the base of the grasping appendages closely resemble the venom glands of some living arthropods in size,shape,and position.These features indicate that the presence of venomous predators could date back 520 million years.Furthermore,our observations suggest that the feeding strategies and organs adapted for this purpose had already reached a high level of diversity and anatomical sophistication in the Early Cambrian ecosystems.     

Normalized transfer function for characterizing conversion efficiency and harmonic distortion of all-optical sampling

A novel method for characterizing the nonlinearity of all-optical sampling is proposed based on the normalized transfer function.Simulation results demonstrate the effectiveness of our method.Furthermore,an all-optical sampling experiment is performed to verify our method.Both simulation and experiment show consistency between our method and the measurements.The method only requires normalization and polynomial fitting of the transfer curve,and enables direct expression of the nonlinearity with the coefficients of the normalized transfer function.     

Mn对SrTiO3基电容—压敏陶瓷非线性系数的影响

介绍了ＳｒＴｉＯ３基电容－压敏陶瓷研究的国内外进展，从理论和实验出发研究了Ｍｎ对ＳｒＴｉＯ３基电容－压敏陶瓷非线性系数的影响，并得到了一些有益的结论。     

书法意象初探

从研究分析古代有关书法意象的论述入手 ,对有关理论进行梳理剖析 ,探寻了书家由物象到书法意象的取向和人们由书法的意象形式到主观内宇宙和有灵世界各种物态及生命形象的联想方向     

Mean Motions in Ptolemy’s <Emphasis Type="Italic">Planetary Hypotheses</Emphasis>

In the Planetary Hypotheses, Ptolemy summarizes the planetary models that he discusses in great detail in the Almagest, but he changes the mean motions to account for more prolonged comparison of observations. He gives the mean motions in two different forms: first, in terms of ‘simple, unmixed’ periods and next, in terms of ‘particular, complex’ periods, which are approximations to linear combinations of the simple periods. As a consequence, all of the epoch values for the Moon and the planets are different at era Philip. This is in part a consequence of the changes in the mean motions and in part due to changes in Ptolemy’s time in the anomaly, but not the longitude or latitude, of the Moon, the mean longitude of Saturn and Jupiter, but not Mars, and the anomaly of Venus and Mercury, the former a large change, the latter a small one. The pattern of parameter changes we see suggests that the analyses that yielded the Planetary Hypotheses parameters were not the elegant trio analyses of the Almagest but some sort of serial determinations of the parameters based on sequences of independent observations.     

引发剂用量对ABS树脂冲击强度的影响

采用种子乳液聚合技术，以K2S2O8为引发剂合成了一系列PB－g－SAN接枝共聚物。并与SAN树脂进行共混，制得了ABS树脂。考察了引发剂K2S2O8用量对PB－g－SAN接枝共聚物的接枝率及制得的ABS树脂的冲击 强度的影响。研究了PB－g－SAN接枝共聚物的接枝率与ABS树脂的冲击强度间的关系。讨论了乳液聚合过程中K2S2O8的引发、扩散机理。     

铅烷发生的酸性模式与碱性模式的对比研究

用FI－HG－AAS系统对K2Cr2O7体系铅烷发生的碱性模式与酸性模式进行了对比研究，观察反应中反应物摩尔量与铅烷产率关系后发现酸性模式与碱性模式有相同的规律，采用高浓度K2Cr2O7氧化，其还原产物Cr(Ⅲ）会生成CrBn沉淀，严重吸附铅离子，导致铅信号下降。     

用热电厂碱性废水脱除循环冷却水中Ca^2＋，Mg^2＋的研究

考察用热电厂碱性废水作为循环冷却水或补充水处理药剂的作用，研究了该废水中的碱性物质与循环水中Ca^2 、Mg^2 两种主要离子结合的规律。结果表明：热电厂碱性废水含有大量的氢氧化钙，将其配入循环水中，能与其中的重碳酸钙和重碳酸镁反应，生成难溶的碳酸钙和氢氧化镁沉淀物，降低了Ca^2 ,Mg^2 两种主要离子的含量。如果再配入一定数量的其他碱性废水，则循环冷却水软化效果更为明显。     

新疆春大豆群体光合、呼吸特性的研究

研究了新疆春大豆高产（4500kg.hm^-2)条件下群体光合速率，呼吸速率的变化。结果表明，高产大豆群体光合速率在整个生育期的变化呈单峰曲线，在开花期以前稳定上升，至结荚期达到最大，为4.165gCO2.m^-2.h^-1，鼓粒末期开始下降，全生育期平均值为2.321gCO2.m^-2.h^-1。群体呼吸速率随生育时期的变化呈现单峰曲线，盛荚斯达到最大值，为1.962gCO2.m^-2.h^-1。群体呼吸速率日变化的趋势与光合速率相似，亦呈现单峰型曲线，至中午14：00－16：00达最大值，呼吸速率的日变化与温度成显著正相关。     

南方果园草情调查及化学除草的研究

在本校果园进行杂草种类初步调查，共有17科52种杂草，主要有马唐、狗牙根、空心莲子草、膨蜞菊等。除草试验结果表明：草苷膦、春多多1000倍液对各种杂草有明显的防除效果，30d总防效达92%以上，持效期长；克芜踪药后15d药效达92.7%，但持效期短，30d后有幼草萌芽；拿捕净对禾本科有较好防效，对莎草科杂草及阔叶杂草无防除作用。