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The preparation and physical properties of the estertin halides X 4-nSn[ (CH2)mCO2R]n, where n = 1 or 2, m = 1, 2 or 3 and R is a alkyl or aryl substituent are reported. During the course of this work the molecular structures of Cℓ3SnCH 2CH2CO2Pri and Cℓ3SnCH 2CH2CO2CO2Et were determined. The preparations of Ph3Sn(CH2)3R compounds, where R is a functional group, are reported. The reactions of these compounds with electrophiles were investigated as a route to organotin halides. Explanations on their reactivity are postulated. The preparation of Ph3Sn[CHRR'] compounds where R and R' are the same or different functional groups, from the reaction of (Ph3Sn) 2S with Hg[CHRR']2 is also reported along with the physical properties and evidence for their particular structures. Investigations into the Lewis acidity of estertin halides were undertaken. Chloride ion acceptor strengths, adduct formation with nitrogen bases and catalysis of allylic rearrangement were used as a basis for the evaluation of the Lewis acidity. Explanations are offered for the various observations made during these studies. Finally the preparations of estertin mercaptides, [Et02C(CH 2)]n Sn(SCH2CO2C8H 17)4-n, where n = 1 or 2 are reported. Comparisons of the P.V.C. stabilising ability of these estertin mercaptides were made with the commercially available octyltin tris-mercaptide. Explanations are offered for the apparent difference in stabilising ability of each of these compounds in thermally processed P.V.C. during oven testing.

Chinese is very different from alphabetical languages such as English, as there are no delimiters between Chinese words. So Chinese segmentation is an important step for most Chinese natural language processing (NLP) tasks. We propose a tightness continuum for Chinese semantic units. The construction of the continuum is based on statistical informations. Based on this continuum, sequences can be dynamically segmented, and then that information can be exploited in a number of information retrieval tasks. In order to show that our tightness continuum is useful for NLP tasks, we propose two methods to exploit the tightness continuum within IR systems. The first method refines the result of a general Chinese word segmenter. The second method embeds the tightness value into IR score functions. Experimental results show that our tightness measure is reasonable and does improve the performance of IR systems.

The withanolid compounds (Tubocapsanolide A, B, and C) were purify from Tubocapsium anomalum and shown with cell growth inhibitory property. However, the molecular mechanisms of withanolide type compounds on the cell have not been fully clarified. Tubocapsanolide A, B, and C (TA, TB, and TC) of antiproliferative activity on human colorectal adenocarcinoma cells, HT29 and HCT116, were tested and the inhibitory concentration of 50% cell viability (IC50) for these compounds was determined by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. We found that TA has the best inhibitory effect in these compounds. Therefore we utilized TA to study the mechanism of cell toxicity. The caspase 3 and PARP cleavage experiment results indicated that TA induced apoptosis was time and dose dependent. Cells with functional p53 (HCT116) are more sensitive to TA compared to the mutant p53 cells (HT29). With low dose TA treatment, HCT116 and HT29 are arrested at G1 and G2/M phase respectively. We also found that TA induced sub-G1 accumulation and reactive oxygen species (ROS) release with flow cytometry analysis. Pretreatment of N-Acetyl-L-cysteine (NAC), an antioxidant agent, can reverse the antiproliferation effect by TA. Our results indicated that TA can induce cell apoptosis and intracellular ROS generation. The ROS triggers cells damage and decreases the mitochondria membrane potential and thus induce cell apoptosis.

Abstract The effect of joint strength of PbSn and AuSn solder on temperature cycling tests in laser packages has been studied experimentally and numerically. It was found that the solder joint strength increased as temperature cycle number increased, and then became steady after 400 cycles. This is may be due to the redistribution of the residual stresses within the solder during temperature cycling test, and hence reducing the residual stresses and increasing the solder joint as the temperature cycle increased. Numerical calculations were in good agreement with the experimental measurement that the solder joint strength increased as the temperature cycle increased. In this work, we also study the intermetallic compound (IMC) growth of PbSn and AuSn solders under cycling test and aging test. The thickness of IMC growth do not significantly increase under cycling test, because the cycling test temperature was from ¡V40 to 85ºC. However, under the high temperature aging of 200ºC for 25 days, the IMC thickness was increased to 4.71£gm.

The 1:1 reaction between MgR2 and diphenylamine gave heteroleptic alkyl -magnesium amide monomeric compounds [RMgNPh2(THF)2] [R=Et (1) and iPr (2)]. Subsequently, addition of stronger donor solvent HMPA to compound 1 results in the disproportionation reaction to give a bisamidomagnesium crystal [Mg(NPh2)2(HMPA)2] (3). The different size secondary amine HNEt2 or HN(SiMe3)2 reacting with Grignard reagent EtMgBr produced diethylamino-bridging and bromo-bridging Hauser base [(Me3Si)2NMg(£g-Br)(OEt2)]2 (4) and [BrMg(£g-NEt2)(HMPA)]2(5) respectively. Unexpectedly, [(Me3Si)NMg (£g-OEt)(THF)]2 (6) was obtained from the reaction of MgEt2 and HN(SiMe3)2 in the refluxing THF solution. Additionally, iPrMgBr and MgY2 (Y = iPr, C

The effect of joint strength of PbSn and AuSn solder in aging test for laser module packaging has been studied experimentally. The thermal conditions were aged at 150 ¢J for 1,4,9,16,25 and 36 days. It was found that the joint strength decreased as aging test time increased. The joint strength of PbSn solder with the gold coating on SUS304 substrate of 2 µm and 10 µm decreased about 17% and 28% after aging test, respectively. The joint strength of PbSn solder with the gold coating on SUS304 substrate of 2 µm and 10 µm decreased about 16% and 9% after aging test, respectively. we also presented the microstructure of the intermetallic compound ¡]IMC ¡^growth under aging test. Results showed that the thickness of the IMC increased after aging test. The growth thickness of the IMC from 1 to 36 days for the PbSn and AuSn solder were measured to be 5.26 to 34.37 and 0.48 to 1.64 µm, respectively. The joint strength decreased under aging test may be due to the crack and void defects increased within the solder. The crack and void defects in solder were observed by metallographic photos.