低密度聚乙烯光引发交联机理Ⅲ．模型化合物n－C＿（24）H＿（50）的￣（13）CNMR研究

用溶液高分辨￣（１３）ＣＮＭＲ谱首次研究了由二苯甲酮（ＢＰ）光引发低密度聚乙烯模型化合物直链烷烃ｎ－Ｃ＿（２４）Ｈ＿（５０）交联所产生的Ｈ型交联点的结构特征．现已检测和鉴定了光交联样品中与Ｈ型交联点相联系的－ＣＨ，α－ＣＨ＿２和β－ＣＨ＿２上碳的共振谱线，其数据与Ｈ型交联点模型化合物、γ－辐射交联正烷烃和聚乙烯所得到的结果符合得很好．在４０．８３ｐｐｍ处出现的一个新峰可指认为Ｈ型文联点的次甲碳，其相应的３１．５７和２８．３７ｐｐｍ处的另外两个新峰分别指认为相邻的α－ＣＨ＿２和β－ＣＨ＿２上碳的共振．本工作中的定量研究表明：在真空和熔融态条件下莱外光照３－５ｍｉｎ的样品中Ｈ型交联点的数目据估计为每１００００个碳原子８．５～１１．０个．     

用硫氰铁铵-氯仿体系光度法测定尿样中的聚乙二醇-600

本文是基于在聚乙二醇－６００（ＰＥＧ－６００）存在下Ｆｅ（ＳＣＮ）３在水相和氯仿相之间进行分配，光度法定量测定尿样的ＰＥＧ－６００。ＣＨＣｌ３相的最大的吸收波长为５０５ｎｍ，振摇时间３０分，检测限为０．２５ｇ／Ｌ，线性范围０．２５～２．５ｇ／Ｌ，回收率１０７％，相对标准偏差（ＲＳＤ）小于５％。该法操作简单，方便，重复性好，可用于临床上尿样中ＰＥＧ的测定。     

Eu2（DBM）6 4,4‘—BIPY的合成,光谱及铕（Ⅲ）格位

合成了配合物Ｅｕ２（ＤＢＭ）６４，６｀－ＢＩＰＹ，ＩＲ和Ｒａｍａｎ光谱都证实了配合物的生成，７７Ｋ正派激发高分辨激光激发光谱和荧光光谱表明配合物存在＾５Ｄ０能级能量差别为１５ｃｍ＾－１的两种Ｅｕ（Ⅲ）格位，两种Ｅｕ（Ⅲ）离子均不位于对称中心，由＾５Ｄ０→＾７Ｄ０．１，２跃迁荧光光谱峰数判断，两种Ｅｕ（Ⅲ）格位的区域对称性均为Ｃ１或Ｃ２或Ｃ，两种格位Ｅｕ（Ⅲ）离子的发光寿命分别为０．３７ｍｓ和０．３     

EuCl3.6H2O中Eu^3＋的^5D0—^7F0跃迁的“反常”温度效应及其跃迁机制研究

研究了ＥｕＣｌ３．６Ｈ２Ｏ的Ｅｕ＾３＋的＾５Ｄ０－＾６Ｆ０“禁戒”跃迁的机制有其“反常”温度效应。通过比较没温度下荧光光谱中＾５Ｄ０－＾６跃迁和＾５Ｄ０－＾７Ｆ０跃迁第一条谱线的强度比，发现由于晶格振动，＾７Ｆ２态通过四个频率为２４５ｃｍ－１的声子与＾７Ｆ０态耦合，使＾７Ｆ０态成为混合态，因而使＾５Ｄ０－＾７Ｆ－的跃迁成为可能，并且其振子强度随温度的变化而变化。     

南中国海海藻刺状鱼栖苔的化学成分研究(I)

从采自南中国海红藻刺状鱼栖苔的乙醇提取物中分离出一个黄酮类化合物，经ＩＲ，ＵＶ，ＦＡＢＭＳ，１Ｈ－１ＨＣＯＳＹ，１３Ｃ－１ＨＣＯＳＹ，ＨＭＢＣ等现代波谱技术确定其结构为５，７－二羟基－２－对羟基苯基－３－Ｏ－（６－Ｏ－对羟基肉桂酰基－β－Ｄ－吡喃葡萄糖基）－４Ｈ－１－苯并吡喃－４－酮，并对碳信号进行了明确归属．这是首次从红藻中分离出黄酮类化合物．     

雷公藤精（Wilforgine）的2D NMR研究

用２Ｄ ＮＭＲ（＾１Ｈ－＾１ＨＣＯＳＹ，＾１Ｈ－＾１３Ｃ ＣＯＳＹ，ＴＯＣＳＹ，ＮＯＥＳＹ和ＣＯＬＯＣ）技术研究了从雷公藤中分离到的雷公藤精，对＾１Ｈ和＾１３Ｃ谱进行了归属。     

析相光度法测定铜（Ⅱ）的研究

本文研究了Ｃｕ－ＰＥＧ－ＤＤＴＣ（铜试剂）（ＮＨ４）２ＳＯ４体系的析相光度法并应用于测定Ｃｕ。最宜酸度为３．６－９．０（ＮａＡｃ－ＨＡｃ，ＮＨ４Ｃｌ－ＮＨ３．Ｈ２Ｏ）缓冲溶液，其络合物的最大吸收位于４５０ｎｍ，表观摩尔吸光系数为９．０５×１０＾３Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，Ｃｕ浓度在０－３０μｇ／Ｌ范围内服从比耳定律，铜与ＤＤＴＣ形成组成为１：２的稳定络合物。该方法用于铝合金中铜的测定，获得了满     

超声雾化空气－氩ICP－AES的检出限

医用超声雾化器改装后作为ＩＣＰ－ＡＥＳ的进样装置。在高频功率３．８×０．８０ｋＷ，载气流量０．８０Ｌ·ｍｉｎ（－１），观察高度１．０ｃｍ的折衷条件下，测定了２７种元素的检出限，１５种稀土元素中Ｄｙ、Ｅｕ、Ｈｏ、Ｙ和Ｙｂ的检出限低于１μｇ·Ｌ（－１）。     

铜与2-羟基-3-羧基-5-磺酸基苯重氮氨基偶氮苯反应的分光光度法研究及应用

研究了铜与２－羟基－３－羧基－５－磺酸基苯重氮氨基偶氮苯（ＨＣＳＤＡＡ）的显色反应。在Ｔｒｉ－ｔｏｎＮ－１０１存在下和ｐＨ１０．４～１１．５的缓冲介质中，Ｃｕ２＋与ＨＣＳＤＡＡ形成１∶２的红色配合物，其最大吸收波长是５３０ｎｍ，对比度为１０２ｎｍ，表观摩尔吸光系数为１．３１×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。铜在０～０．２４μｇ／ｍＬ范围内服从比尔定律。用于铅锌矿和花生中微量铜的测定，相对误差不大于３．７％，相对标准偏差不大于１．６％（ｎ＝６）。     

不除氧条件下环糊精诱导室温磷光法测定喹啉

在不除氧条件下，１０ｍＬ含喹啉／β－ＣＤ溶液中只需加入１５μＬ１，２－二溴丙烷（ＤＢＰ）作重原子微扰剂，就能产生强而稳定的室温磷光信号。最大λｅｘ／λｅｍ＝２７３／４９６ｎｍ。喹啉浓度在５．０×１０＾－７￣５．０×１０＾－５ｍｏｌ／Ｌ，５．０×１０＾－４ｍｏｌ／Ｌ，两段三个数量级范围与室温磷光信号有良好的线性关系，最低检测限７．４×１０＾－８ｍｏｌ／Ｌ。本体系的特点是ＤＢＰ用量少，从而减少了因过量     

低密度聚乙烯光引发交联机理IV.H-和Y-型交联点结构的13C NMR研究

首次用溶液高分辨¹³C NMR研究了由二苯甲酮光引发低密度聚乙烯(LDPE)交联所产生的交联结构,现已观测和鉴定了H型和Y型长链支化两类交联点。对于熔融态紫外光交联5-10s的LDPE样品,其H型和Y型交联点的浓度据估测分别为一万个碳原子中有5.7-16.9和7.6-21.6个结构单元。     

低密度聚乙烯光引发交联机理——Ⅱ.BNB自旋捕捉ESR研究

在光引发剂二苯甲酮(BP)存在下,紫外光辐照低密度聚乙烯(LDPE)所形成的自由基中间体已被自旋捕捉剂2,4,6-三特丁基亚硝基苯(BNB)所捕捉,其自旋加合物自由基已为电子自旋共振(ESR)所特征。现已检测和鉴定到二种自旋加合物:一种是叔碳自由基;另一种是仲碳自由基。它们分别是由BP的激发三重态从LDPE链的支化点和亚甲基团上夺氢所形成的自由基中间体同自旋捕捉剂BNB反应生成的。上述的证据表明:LDPE的光引发交联点主要发生在叔碳和仲碳原子上,且H-型交联点占主导地位。     

Phase Diagrams of Semicrystalline Polymer–Crystalline Substances: Polyolefins–1,2,4,5-Tetrachlorobenzene

The full phase diagrams of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and isotactic polypropylene (i-PP) mixtures with 1,2,4,5-tetrachlorobenzene (TeCB), including the solubility curve of TeCB in a solid polymer, were constructed by an optical method. The diagrams contain a eutectic point that corresponds to the situation when the crystallization of TeCB out of its solution in a polyolefin is accompanied by the crystallization of monomer units of the macromolecules. As a result, the polymer acquires a gel structure with crystallites as crosslinks and amorphous regions saturated with TeCB. It is demonstrated that the eutectic point position on the phase diagram can be used for ranking polymers with respect to their thermodynamic affinity to a solvent. For the studied systems, the affinity to TeCB was decreased in the order i-PP, HDPE, and LDPE. Direct experimental evidence was obtained that TeCB crystals can be dissolved in a solid polymer via a vapor phase mechanism, which leads to the polymer amorphization.     

低密度聚乙烯光引发交联机理Ⅴ.光引发剂二苯甲酮光解产物的NMR研究

用NMR技术对光引发剂二苯甲酮(BP)引发低密度聚乙烯模型化合物正二十四烷、正十二烷、鲨烷(异三十烷)、异辛烷和乙烯-1紫外光交联过程中的光解产物进行了检测和研究.井首次确定了BP在光引发交联体系中光解的主要产物为苯并哪醇(1,1,2,2-四苯基-1,2-乙二醇),为BP光引发聚乙烯交联的机理提供了直接的实验证据.     

MORPHOLOGY OF SEMICRYSTALLINE FOAMS BASED ON POLYETHYLENE

The matrix polymer morphology of a collection of low-density polyethylene (LDPE) foams manufactured from a high-pressure nitrogen solution process is analyzed at different length scales. This morphology is compared with that of the extruded LDPE, which was used to produce the foams. The main sources for the differences between the morphologies of both kinds of material seem to be related to the geometrical arrangement of the polymer in thin cell walls and to the complicated mechanical and thermal history of the polymer that comprises the cell walls of the foams.     

SPECIAL LINE-SHAPES OF TWO-PHOTON TRANSITIONS IN A Y-TYPE FOUR-LEVEL SYSTEM BASED ON QUANTUM INTERFERENCE

The experimentally observed special line-shape induced by the interaction between two counter-propagating equal-frequency fields and an Y-type four-level system with two mixed upper levels has been analyzed theoretically. Serious line-shape variations of the two-photon transitions due to the quantum interference are discussed and predicted.     

低密度聚乙烯光引发交联机理——Ⅰ.ND自旋捕捉ESR研究

本文使用2,3,5,6——四甲基亚硝基苯(ND)自旋捕捉ESR技术研究了由二苯甲酮(BP)光引发低密度聚乙烯(LDPE)交联自由基中间体。采用改变温度和熔融态检测到分辨得很好的氮氧自旋加合物自由基ESR谱的方法,鉴定了光引发LDPE交联前躯自由基主要为仲碳自由基,-CH_2-CH-CH_2-和叔碳自由基,由此可见,BP引发LDPE的光交联反应主要发生在仲碳和叔碳原子上。     

低密度聚乙烯光引发交联机理——Ⅱ.BNB自旋捕捉ESR研究(英文)

在光引发剂二苯甲酮(BP)存在下,紫外光辐照低密度聚乙烯(LDPE)所形成的自由基中间体已被自旋捕捉剂2,4,6-三特丁基亚硝基苯(BNB)所捕捉,其自旋加合物自由基已为电子自旋共振(ESR)所特征。现已检测和鉴定到二种自旋加合物:一种是叔碳自由基;另一种是仲碳自由基。它们分别是由BP的激发三重态从LDPE链的支化点和亚甲基团上夺氢所形成的自由基中间体同自旋捕捉剂BNB反应生成的。上述的证据表明:LDPE的光引发交联点主要发生在叔碳和仲碳原子上,且H-型交联点占主导地位。     

Effects of Roller Speed,Die Temperature,Volumetric Flow Rate,and Multiple Extrusions on Mechanical Strength of Molten and Solidified LDPE under Tensile Deformation

An experimental rig coupled with a high speed data-logging and recording system and a personal computer was specially designed and constructed for the real-time measurement of mechanical strength (in terms of drawdown force) as a function of volumetric flow rate and roller speed for virgin low-density polyethylene (LDPE) and reprocessed LDPE during a filament stretching process. The effect of the number of extrusion passes for the reprocessed LDPE was our main interest. The experimental rig was connected to the end of a single-screw extruder, which was used to melt and extrude the polymers. The LDPE filaments were then solidified and collected for studying the mechanical properties. The mechanical strength of the virgin LDPE and reprocessed LDPE were investigated in both molten and solidified states. The mechanical strengths of the virgin and reprocessed LDPEs under these two states are discussed and compared in terms of change in magnitude under a wide range of processing conditions (volumetric flow rate, die temperature, and roller speed). The results suggested that in the molten state the drawdown force for LDPE melts was dependent on volumetric flow rate, die temperature, roller speed, and the number of reprocessing passes. The drawdown force being affected by the number of reprocessing passes could be explained by molecular degradation and gelation effects when using high volumetric flow rates. In the solidified state, the tensile properties of the solidified LDPE increased with roller speed. The effect of the number of extrusion passes for the solidified LDPE was similar to that for the molten LDPE. In the case of volumetric flow rates, the mechanical properties of the solidified LDPE decreased with increasing volumetric flow rate, whereas those of the molten LDPE exhibited the opposite effect. Thus, the mechanical strength of the molten LDPE could not always be used to assess the mechanical properties of the solidified LDPE.     

A new method to measure fat content in coconut milk based on Y-type optic fiber system

This paper presents a new method of measuring fat content in coconut milk at room temperature (25 °C) based on the designed Y-type optical fiber measurement system and makes the analysis and evaluation of this system. The system consists of light source, Y-type optical fiber, signal amplification module, signal conversion module and microprocessor module. The new method of assessing the accuracy of the measurement system – R&R (Repeatability and Reproducibility) assessment method is introduced here. It makes the effective analysis and evaluation and judges the reliability of the Y-type optical fiber system, laying the foundation for obtaining high quality data. The results show that the designed measurement system has high precision and can satisfy the measurement of this kind of samples.