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1.
借助于分子拓扑学探讨了正烷基环戊烷的熔点与分子结构的关系,提出了一个结构基础明确的定量关系,对甲基环戊烷到正三十六烷基环戊烷的计算结果表明,熔点计算值都很拉近实验值,平均误差仅0.111%?应用这一定量关系,兴驻能够合理表征正烷基环戊烷结构与烷点的关系,而且有助于提示物质结构与性能关系之间的奥秘。  相似文献   

2.
应用密度泛函理论,研究了丙烯在800 K发生热反应产生1,4-双自由基的2条去路:(1)1,4-双自由基闭环形成1,2-二甲基环丁烷;(2)1,4-双自由基经氢迁移产生1,5-双自由基而后闭环形成甲基环戊烷.分析比较产物的生成热可知:生成甲基环戊烷的反应机理更为合理,计算结果与实验一致.  相似文献   

3.
以2,5-二羟基-1,4-二噻烷为起始原料,经立体有择反应和利用保护试剂三氟甲基磺酸三甲基硅酯合成得到(2R,5R)-5-羟基-1,3-氧硫杂环戊烷-2-羧酸-(1R,2S,5R)-2-异丙基-5-甲基环己酯(I)、(2R,5R)-5-乙酰氧基-1,3-氧硫杂环戊烷-2-羧酸-(1R,2S,5R)-2-异丙基-5-甲基环己酯(Ⅱ)和(2R,5S)-5-(6-氨基-嘌呤-9-基)-1,3-氧硫杂环戊烷-2-羧酸-(1R,2S,5R)-2-异丙基-5-甲基环己酯(Ⅲ).经过1H NMR和质谱及晶体结构分析等手段对其进行了结构表征.结果表明:化合物Ⅱ属于正交晶系,P212121空间群;晶胞参数a=0.533 O(1)nm,b=1.453 5(1)nm,c=2.354 7(1)nm,Z=4,V=1.824 2(4)nm3,Dc=1.174 g/cm3.最终可靠因子R1=0.072,wR2=0.063.分子中共有两个环,5个手性中心,六元环呈椅式构象,五元环呈信封式构象.  相似文献   

4.
北极楚科奇海氟氯烃CFC-11的分布特征及其化学示踪   总被引:1,自引:0,他引:1  
2008年7—9月于北极楚科奇海采集了17个站位不同深度的海水水样,用吹扫捕集与气相色谱相结合的方法分析氟氯烃CFC11(CCl3F)的含量分布,并结合温度、盐度、溶解氧等水文和海洋化学数据用于楚科奇海水的化学示踪研究.结果表明,楚科奇海表层水中CFC-11的含量在2.95~8.81 pmol/kg之间,表层水与30 m层水还没完全混合;Her-ald浅滩南边为夏季太平洋入流水,而以北仍然为冬季陆架残留水;CFC-11高值进一步证实阿纳德尔水、白令海陆架水与阿拉斯加沿岸流在Barrow峡谷混合,CFC-11低值则证实北极中层水增暖现象,CFC-11表层含量的显著增加表明楚科奇海陆坡区离岸较近的地方受到河流径流的影响.  相似文献   

5.
采用悬浮聚合法合成了可发性聚苯乙烯(EPS),研究了戊烷用量对EPS粒径、产品细粉率、玻璃化转变温度、分子量和戊烷在EPS产品中分散情况的影响,并通过DSC、GPC和电子显微镜分析手段对产品进行了测试。结果表明,戊烷用量的增加使产品的平均粒径增加,玻璃化转变温度和分子量减小;当戊烷用量为2.14%(质量分数)时,戊烷在产品中分散较好,当用量为2.67%时,细粉率达到最小值0.42%。  相似文献   

6.
因环戊烷是易燃易爆危险物品,且储存量大于临界量,故某企业储存环戊烷的贮罐站是可燃液体贮罐重大危险源。作者主要针对该站的工艺流程、系统组成及系统功能的特点,应用故障模式和影响分析方法,找出了该站中各主要子系统及部件可能发生的故障模式及故障原因。根据对系统或设备影响的严重程度,确定故障模式的危险等级,计算出故障导致环戊烷燃烧爆炸事故的能量及伤害后果,为制定有效的安全技术措施和管理制度,防止同类事故发生提供科学依据。  相似文献   

7.
测定了环戊烷在 Pt/γ-Al_2O_3上积炭的生成速率、表现活化能及反应级数,分析了积炭的组成结构及 H/C 值,提出积炭反应在不同温度有两种不同的积炭机理。  相似文献   

8.
氟利昂无害化与资源化处理技术已成为当今环保领域的研究热点.采用混合沉淀过饱和浸渍法制备MoO_3/ZrO_2-TiO_2固体酸催化剂.将氟利昂通入以石英砂为催化剂填料载体的催化反应床中,利用管式炉加热,进行催化水解实验.从水解温度、水蒸气体积分数等反应条件考察了MoO_3/ZrO_2-TiO_2固体酸催化剂对CHClF_2(HCFC-22)和CCl_2F_2(CFC-12)降解效果的影响.结果表明,500℃焙烧的MoO_3/ZrO_2-TiO_2固体酸在相同的条件下催化水解HCFC-22和CFC-12,HCFC-22的降解率高于CFC-12,HCFC-22比CFC-12容易水解.两者的主要水解产物均为CO、CO_2、HF和HCl.被吸收后的产物为氟离子和氯离子,成分简单,经简单处理可被回收利用.反应60 h后HCFC-22和CFC-12的降解率仍维持在70%以上.由此可见,MoO_3/ZrO_2-TiO_2固体酸催化剂催化水解HCFC-22活性高且稳定性好.XRD和SEM表征表明,MoO_3/ZrO_2-TiO_2催化剂的主要结构为四方晶相的Zr(MoO_4)2掺杂锐钛型的TiO_2.  相似文献   

9.
1,6-二(取代笨基)已二酮-1,6(ArCOCH_2CH_2CH_2CH_2COAr,Ar=4-CH_3C_6H_4-,4-CH_3OC_6H_4-,4-ClC_6H_4-,3,4-(CH_3O)_2C_6H_3-)溴化生成相应的2,5-二溴-1,6-(取代苯基)已二酮-1,6,后者与甲醇钠作用生成3-溴-1-取代苯甲酰基-2-取代笨基-1,2-环氧环戊烷。芳环上不同的取代基对生成的取代环氧环戊烷的产量似乎没有什么影响。  相似文献   

10.
以异戊醇和氢溴酸为原料 ,改性镍钼粉为催化剂 ,催化合成 3,1-溴代异戊烷。探索出适于合成 1-溴代异戊烷的工艺控制条件 ,由异戊烷与氢溴酸物质的量比为n(异戊烷 ) :n(氢溴烷 ) =1 0 :2 5 ,催化剂用量为m(异戊烷 ) :m(催化剂 ) =1 0 0 0 :0 12 5 ,反应温度为 10 0~ 110℃ ,反应时间为 2h ,1-溴代异戊烷的收率为 :90 %。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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