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Chiral fluorinated side-chain liquid-crystalline elastomers (LCEs)IP-IVPwere graft copolymerized by hydrosilylation reaction. The chemical structure, liquid-crystalline behavior and polarization property were characterized by use of various experimental techniques. The effective crosslink density of the chiral LCEs was studied by swelling experiments. All the samplesIP-IVPdisplayed chiral smectic C mesophase (SC*) on heating and cooling cycles. With increasing chiral crosslinking units in the elastomer systems, the glass transition temperature and chiral smectic C mesophase-isotropic phase transition temperature of fluorinated elastomers increased slightly, indicating that the temperature range of SC*mesophase became narrow with increase of chiral crosslinking agents for all the chiral fluorinated elastomers. All the samplesIP-IVPshowed 0.12-0.16 μC/cm2of spontaneous polarization.

A new class of three-armed star-shaped liquid crystals 5a-5d were synthesized, they used 1,3,5-trihydroxybenzene as a core, ω-[4-(p-ethoxybenzoloxy) phenoxycarbonyalkyl acid (3a, 3b) and ω-[4-(p-nitrobenzoloxy) phenoxycarbonyalkyl acid (3c, 3d) as mesogenic arms. Their chemical structures were confirmed by FTIR and 1H NMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that the three-armed star-shaped liquid crystals exhibited a broad range of liquid crystalline phases at moderate temperature. The mesogenic arm structures obviously affected the phase behavior. As the intermedius alkyl chain of the star-shaped compounds lengthened (from n=4 to n=8), their melting points decreased but mesomorphic temperature ranges increased. The temperatures when 5% weight loss occurred (td) were higher than 300°C, which revealed that the synthesized three-armed liquid crystals had a high thermal stability. Threadlike, droplet and schlieren texture, typical of nematic phase can be observed in the liquid crystalline state during heating or cooling process.

A series of new main-chain liquid-crystal polymers (LCPs) were prepared from sebacoyl chloride (SD) and various amount of 4, 4-Dihydroxy-2, 2-dimethyl Benzalazine (DDBA) and isosorbide (ISO). The liquid crystal (LC) properties were investigated by polarized optical microscope (POM), differential scanning calorimetry (DSC) and X-ray diffraction measurements. P1 exhibited a typical nematic thread texture, which contains no ISO. P2-P7 are Sc* and N LCPs, which exhibited broken fan-shaped texture and droplet texture. The introduction of chiral units into the polymers led to a change of mesomorphase, as compared with P1.

Modeling for complex spiral wire rope structures, on which the mechanical performances largely depend, are paramount to finite element analysis application. Three mathematical modeling thoughts were brought out to create the geometric models of wire rope strands. The first one was presented based on the centerline times of the helical structures, as the centerline times can be decreased through transitional coordinate system. For the second, the centerlines of the wire rope were formed by the helical movement of predefined point. In the third one, a local coordinate system which can be transformed into the world coordinate system by their relationship was employed. The above three ideas were implemented by different kinds of derivation. The geometric parameter equations were presented to express the accurate wire rope models. These approaches are beneficial for parametric modeling and analysis of wire rope strands.

Parametric modeling of transition tubes were implemented based on constant cross section area assumption along the main central routes on CATIA software. The key objective of modeling these similar structures is to provide more geometric configuration options and modifications of micro channels for multi phase flow systems. The modeling processes were parameterized and analyzed by CATIA “Generative Shape Design” module with the help of “Parameters” and “Relations” functions. The surface models are all designed in circular cross sections that are constrained in two ways: one is perpendicular to the main central routes of the tube for planar transitional junction, and another is, perpendicular to the sub-branch central routes for oblique transitional junction three dimensionally. Next work is emphasized on numerical simulation and experimental investigation with these geometric structures in a multi phase flow system.

The synthesis of new chiral monomer 4-(menthyloxyacetoxy- benzoyloxy)biphenyl-4′-(2-(undec-10-e noyloxy)ethoxy)benzoate (ML), crosslinking agent 4-(undec-10-enoyloxy)biphenyl-4′-(2-(undec-10-enoyloxy)ethoxy)benzoate (CA), and liquid crystal polymer networks (E1−E5) containing menthyl group is presented. Their chemical structures and phase behavior were characterized with Fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), elemental analyses, polarizing optical microscopy, differential scanning calorimetry, thermogravimetric analysis (TGA), and X-ray diffraction. The selective reflection of light for ML was investigated with ultraviolet/visible/near infrared (UV/Visible/NIR). By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, MLcould form mesophase and show a chiral smectic C phase, cholesteric phase and cubic blue phase. CA displayed a smectic A phase and nematic phase. The polymer networks containing less than 12 mol% of the crosslinking units showed reversible cholesteric phase transition, wide mesophase temperature range, and excellent thermal stability. With increasing the content of crosslinking unit, the corresponding Tg increased, the Ti decreased, and the mesophase temperature range narrowed for E1−E5. TGA showed that the Td(5%) was greater than 330°C for E1−E5.

A new chiral mesogenic monomer (MLC) based on menthyl groups and the corresponding cholesteric elastomers (LCE1–LCE3) were prepared. Their chemical structures and purity were characterized by Fourier transform infrared, nuclear magnetic resonance and elemental analyses. The liquid crystalline properties were investigated by differential scanning calorimetry, polarizing optical microscopy, thermogravimetric analysis and X-ray diffraction. The selective reflection of light for MLC was characterized with ultraviolet/visible/near infrared. The effect of the content of crosslinking units on the liquid crystalline behaviour of LCE1–LCE3 is discussed. The experimental results show that the chiral monomer and the corresponding elastomers containing menthyl groups can show mesomorphism when a flexible linkage chain is inserted between the mesogenic core and the bulky terminal menthyl fragments to reduce the steric effect. MLC exhibited a chiral smectic C phase, a cholesteric phase and a cubic blue phase. LCE1–LCE3 with a low content of crosslinking units showed a cholesteric phase because of the introduction of the nematic crosslinking unit. With increasing content of crosslinking units, the corresponding glass transition temperature increased, while the clearing temperature decreased. Thermogravimetric analysis showed that LCE1–LCE3 have good thermal stability. Copyright © 2012 Society of Chemical Industry

The synthesis of a new cholesteric monomer (MLC) containing menthyl groups and a series of cholesteric elastomers (LCE1−LCE4) is described. Their chemical structures and purity were characterized by FTIR, 1H-NMR, and elemental analyses. The phase behavior and thermal stability were investigated by differential scanning calorimetry, polarizing optical microscopy, X-ray diffraction, and thermogravimetric analysis. By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, mesomorphism of MLC was realized. LCE1−LCE4 with low content of crosslinking unit exhibited cholesteric phase because of the introduction of the nematic crosslinking unit. This indicates that low levels of chemical crosslinking do not significantly affect the phase behavior and mesomorphism of the elastomers, and reversible mesophase transitions can be observed. In addition, with increasing the content of crosslinking unit, the corresponding Tg decreased for LCE1−LCE4, whereas their Ti did not remarkable change. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A series of liquid crystalline (LC) polysiloxanes (PI-PV) were prepared by use of poly(methylhydrogeno)siloxane and two kinds of terminal olefinic monomers. The chemical structures and liquid-crystalline properties of the synthesized materials were characterized by various experimental techniques. From PI to PV, the glass transition temperature and the isotropic temperature decreased slightly with increase of terminal fluoromethyl units in the polymer systems. All the monomers and polymers showed nematic phase with wide mesophase temperature ranges. The polymers PI, PII and PIII displayed single nematic mesophase, but PIV and PV bearing more terminal fluoromethyl units showed another smectic mesophase besides nematic mesophase.

The synthesis of new chiral liquid crystal monomers (M1 −M4 ) derived from menthyl groups, the corresponding smectic polymers (P1 −P4 ), and cholesteric elastomers (E1 −E4 ) based on M2 and crosslinking agent (CA ) is presented. The chemical structures and purity were characterised by Fourier transform infrared, 1H nuclear magnetic and elemental analyses. The phase behaviour and mesomorphism were investigated by differential scanning calorimetry, polarising optical microscopy, thermal gravimetric analysis and X-ray diffraction. The selective reflection of light for M1 −M4 was characterised with ultraviolet/visible/near infrared. The structure–property relationships of M1 −M4 and P1 −P4 were studied. The effect of the content of mesogenic crosslinking units on phase behaviour and mesomorphism of E1 −E4 was discussed. By inserting a flexible spacer between the mesogenic core and the terminal menthyl groups, M1 −M4 all showed strong mesomorphism and exhibited an oily streak and focal conic textures of the ch...

A series of liquid crystalline (LC) oligomer films (IP-VP) were prepared by use of cyclo(tetramethylhydrogeno)siloxane (CTMHS), and two different cholesteric monomers that possess ortho- or para-substituted benzene. The chemical structures, liquid-crystalline properties and optical properties of the synthesized materials were characterized by various experimental techniques. All the samples showed cholesteric phase with very wide mesophase temperature ranges. From IP to VP, the glass transition temperature and the isotropic temperature decreased slightly with increase of C2PB component in the polymer systems. The maximum reflection bands shift to long wavelength from IP to VP, suggesting the helical pitch become longer with more ortho-substituted benzene in the polymer systems

Dynamic kill drilling is a technology which is applied in order to control the deep water drilling shallow gas or shallow wells flowing by establish a normal cycle automatically in the deepwater shallow wells section. Equivalent circulating density (ECD) is an important parameters to control the bottom hole pressure, in the ECD estimate, if we don’t consider the effects of low temperature on rheological parameters of drilling fluid, it will result in errors in ECD estimates. Considering the impact of low temperature on the rheological parameters, this paper determines the temperature, rheological parameters and the annulus circulating pressure loss of each well section. Then Superposing each well section annular circulating pressure loss together, and finally calculate the equivalent circulating density. The deeper the water the greater of difference between ECD prediction model and the results calculated by rheological parameters on ground, and the more shallow wells the larger of difference. Therefore, in the process of deep water surface layer dynamic killing, We need to predict the equivalent circulating density of drilling fluids (ECD) accurately.

This paper according to the cases of HuNan ZiJiang coal mining and JiNing coal mining group to analysis the consequences of coal mining workers’ unsafe behaviors, getting the main characteristics of accident which caused by Coal Mining Workers’ Unsafe Behaviors including: dead and injured is more, the economic loss is huge and the society effects is bad, and more further step to analysis the occurrence mechanism which caused by coal mining workers’ unsafe behaviors, at last we find that we should use intervention technology to intervene the coal mining workers’ unsafe behaviors to prevent from causing of the coal mining accident.

The CdZnTe (CZT) devices with various screening depth in dimensions 3×3×6mm3 were fabricated. The influence of Ring length (screening depth) and length of crystal on the electric field distribution in CZT devices has been explored by finite element method. The results indicated that ring length (screening depth) plays an important role on the detecting performance of CZT Frisch-ring devices. Longer screening depth gives rise to an electric field which is compressed more greatly. Measured spectra indicated that extreme compressed electric field could reduce detecting resolution. A FWHM energy resolution of approximately 3.71% at 662 keV was obtained for a device with dimensions 3×3×6mm3 and 4.8mm screening depth.

A novel perfluorinated liquid crystal 4′-(2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoyloxy)biphenyl-4-yl undec-10-enoate (PFOBU) was synthesized, which exhibited smectic C phase. Several liquid crystalline polymers (PI–PVI) were synthesized by use of poly(methylhydrogeno)siloxane, PFOBU, and cholesteryl 3-(4-allyloxy-phenyl)-acryloate. The chemical structures and liquid crystalline (LC) properties of the monomers and polymers, and some ferroelectric properties of the chiral smectic C (S C * ) phase were characterized by use of various experimental techniques. The effect of perfluorocarbon chains on phase behaviors of the fluorinated LC polysiloxanes was studied as well. PI and PII showed single chiral nematic (N*) mesophase when they were heated and cooled, but PIII, PIV, PV, and PVI containing more perfluorocarbon chain units exhibited S C * phase besides N* mesophase. Introduction of perfluorocarbon chain containing mesogens to the chiral cholesteryl-containing polymer systems resulted in a S C * mesophases, indicating that the fluorophobic effect could lead to microphase segregation and modifications of smectic mesophases from the chiral nematic phase.

This paper presents a frequency-tunable high-power mesoband microwave radiator that uses a switched quarter-wavelength oscillator and a patch antenna. The oscillator is charged and then switched by an annular electrode between the inner and outer conductors. The length of the oscillator is adjustable by moving the electrode in order to generate different frequency resonances. A coupler with a quasi-constant coupling coefficient was employed to output a high-power mesoband microwave. A novel high-power wideband patch antenna with a bandwidth of 64% and a maximum gain of 8.1 dB was used to radiate the generated mesoband microwave. The experimental results of the radiation factor were as high as 182 kV at 333 MHz, and the measured center frequency of the radiated mesoband microwaves ranged from 227 to 345 MHz.

e21099Background: The aims of our study were to determine whether perfusion computed tomography (CT) imaging can allow evaluation of the effects of chemotherapy combined with anti-angiogenesis trea...

The synthesis of new chiral monomers (M1−M5) and the corresponding smectic homopolymers (P1−P5) containing menthyl groups is described. The chemical structures and purity were characterized by FT-IR, 1H NMR and elemental analyses. The specific optical rotations were evaluated with a polarimeter. The phase behavior and mesomorphism were investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X-ray diffraction. The selective reflection property of light was studied with UV/visible/NIR. The monomers M2−M5 formed a chiral smectic C ( S C ∗ ) , and cholesteric or blue phase when a flexible linkage chain was inserted between the mesogenic core and the terminal menthyl groups by reducing the steric effect. M1 showed no mesomorphism, while M2−M5 showed enantiotropic S C ∗ and cholesteric phases. Moreover, M5 also exhibited a cubic blue phase on cooling. With increasing temperature, the selective reflection of light shifted to the long wavelength region at the S C ∗ phase range, and to the short wavelength region at the cholesteric phase range, respectively. The homopolymers P1−P5 all exhibited the batonnet textures of a smectic A phase. The melting, clearing, and glass transition temperatures increased, and the mesophase temperature ranges widened with increasing the aryl number in the mesogenic core.

To improve the detecting effects of moving objects, an adaptive background reconstruction algorithm based on inertial filtering is proposed in this paper. According to different properties of the moving foreground and ever-changing background, the current frame is added to the background with a specific weight value. So the background can not only keep steady, but also be reconstructed at a specific speed. Experimental results show that the algorithm can reconstruct the background quickly and effectively whenever the background changes slowly or suddenly, or the background is mixed with moving foreground, and it can improve the veracity and robustness of objects detection effectively.

A novel idea of azimuthal partition to generate high-power microwave (HPM) with two frequencies [named bifrequency (BF)] in a single device is put forward. According to this idea, a C-band BF magnetically insulated transmission line oscillator (MILO) is designed by tuning the cavity-depth of a conventional MILO in azimuthal direction. The analysis of BFMILO reveals that its characteristics such as self-insulated current, total anode current, and total impedance of BFMILO are nearly the same as those of a conventional one. The oscillation of each microwave is restricted in its corresponding partition. Simulation results show that a C-band BFMILO stably yields an HPM output power of about 1.43 GW when the electron beam voltage is 490 kV and the current is about 45 kA. The power efficiency is about 6.5%, and the two frequencies are 3.4 and 3.65 GHz, respectively. The amplitude difference between the two microwaves in the spectrum is about 0.4 dB. Each frequency is mainly distributed in its corresponding partition.

Chiral side-chain liquid-crystalline polysiloxanes (PS-1, PS-2, PS-3, PS-4, PS-5, PS-6) bearing fluorinated units and sulfonic acid groups were synthesized with poly(methylhydrogeno)siloxane, cholest-5-en-3-ol(3β)-4-(2-propenyloxy)benzoate, and 3-trifluoromethyl-phenyl 3-sulfo-4-undec-10- enoyloxy-benzoate. The effects of fluorinated units and sulfonic acid groups on characteristic of liquid-crystalline properties were studied. PS-1, PS-2, and PS-3 exhibited both smectic and cholesteric mesophases, while PS-4, PS-5, and PS-6 exhibited only cholesteric mesophase. As the polymers contained more fluorinated units and sulfonic acid groups, segregation of the fluorinated segment to the surface and aggregation of hydrogen bonding should occur. Therefore, the highly ordered lamellar mesogen–siloxane matrix systems should be disturbed severely, suggesting that PS-4, PS-5, and PS-6 show no smectic phase. The maximum reflection bands become broad and shifted slightly to long wavelength from PS-1 to PS-6. Copyright © 2008 John Wiley & Sons, Ltd.

This paper reports on the operation of a repetitively pulsed relativistic klystron amplifier at 100 pps. The electron beam was reproducibly modulated to > 74%. Using a 700-kV, 6.5-kA, 25-ns electron beam and a 600-kW Magnetron as inputs, a 1.2-GW radiated power in 20-ns full-width at half-maximum pulses at 2.95 GHz is extracted. The average power is 2.4 kW. The efficiency is 27%, and the gain is about 33 dB

A series of novel three-armed star-shaped liquid crystals based on 1,3,5-trihydroxybenzene as a core and ω-[4-( p -alkoxybenzoloxy)phenoxycarbonyl]valeric acid as mesogenic arms were synthesized. Their chemical structures were confirmed by FTIR and 1 H NMR spectra, their mesomorphic properties and phase behavior were investigated using differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD) measurements. The results show that the three-armed star-shaped liquid crystals exhibit a broad range of liquid crystalline phases at moderate temperature, no crystallization but vitrifying to form glass-forming mesogens during cooling from the isotropic melt. The formed crystals are glassy liquid crystals. The three-armed molecules are highly thermal stable and the mesomorphic ranges (Δ T ) become wider as the terminal alkoxy chains become longer. Threadlike texture, a typical nematic phase, can be observed in the liquid crystalline state.

A series of cyclosiloxane-based cholesteric LCEs were synthesized by using a LC monomer cholest-5-en-3-ol(3β)-4-(2-propenyloxy)benzoate and an ionic divinyl monomer 2,2'-(1,2-ethenediyl)-bis[5-[(4-undecenoyl-oxy)phenyl]-azo]-benzenesulfonic acid. The polymers were prepared in a one-step reaction with ionic crosslinking contents ranging between mass content 0 and 11.8%. Their chemical structures and liquid-crystalline properties were characterized by FT IR, 'H NMR, DSC, POM and X-ray measurement. The effective crosslink density (M c ) was determined by swelling experiments in mixed buffer/organic solvent mixtures, using Brannon-Peppas models. All the polymers exhibit thermotropic LC properties and reveal cholesteric phase. With increase of ionic crosslinking component in the polymers, the melting behavior disappears and the temperature of clear point decreases. Reflection spectra of cholesteric mesophase of the series of polymers showed that the reflected wavelength becomes broad and shifts to long wavelength with increase of the ionic crosslinking component in the polymer systems.

The synthesis of new side chain cholesteric liquid crystalline elastomers containing the flexible non-mesomorphic crosslinking agent M-1 and the cholesteric monomer M-2 by a one-step hydrosilylation reaction is described. The chemical structures of the obtained monomers and network polymers were confirmed by 1H NMR and FTIR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. The glass transition temperatures and isotropic temperatures of the mesomorphic elastomers decreased as the concentration of crosslinking units increased; in the mesomorphic region the liquid crystalline elastomers showed elasticity, reversible phase transitions and Grandjean texture. The flexible crosslinking agent did not disturb the cholesteric structure; moreover, it was beneficial for adjusting the helix of the cholesteric liquid crystalline polymers, and cholesteric elastomers P-6, P-7, show reversible selective ...

A series of ionic liquid-crystalline (LC) elastomers were synthesized by using chemical cross-linking agents containing sulfonic acid groups, which were siloxane-based materials. A ionic divinyl mo...

We have previously shown that Elatoside C reduces cardiomyocyte apoptosis during ischaemia/reperfusion (I/R). Here, we investigated whether Elatoside C improves heart function in isolated rat hearts subjected to I/R and elucidated the potential mechanisms involved in Elatoside C-induced protection.Isolated rat hearts were subjected to global ischaemia followed by reperfusion in the absence or presence of Elatoside C. We found that Elatoside C significantly attenuated cardiac dysfunction and depressed oxidative stress induced by I/R. Consistently, Elatoside C prevented I/R-induced mitochondrial dysfunction, which was evident by the inhibition of mitochondrial ROS production, mitochondrial permeability transition pore (mPTP) opening, cytochrome c release from the mitochondria and Bax translocation. Moreover, Elatoside C improved abnormal calcium handling during I/R, including increasing sarcoplasmic reticulum Ca(2+) ATPase (SERCA2) activity, alleviating [Ca(2+)]ER depletion, and reducing the expression levels of ER stress protein markers. All of these protective effects of Elatoside C were partially abolished by the PI3K/Akt inhibitor LY294002, ERK1/2 inhibitor PD98059, and JAK2/STAT3 inhibitor AG490. Further assessment in isolated cardiomyocytes showed that Elatoside C maintained the Ca(2+) transients and cell shortening against I/R.Elatoside C protects against cardiac injury during I/R by attenuating oxidative stress and [Ca(2+)]i overload through the activation of both the reperfusion injury salvage kinase (RISK) pathway (including PI3K/Akt and ERK1/2) and the survivor activating factor enhancement (SAFE) pathway (including JAK2/STAT3) and, subsequently, inhibiting the opening of mPTPs.

This study is to report the study of protective effects of myricitrin against oxidative stress-induced apoptosis of vascular endothelial cells and the investigation of the possible mechanisms of action of myricitrin. The model of H2O2-induced apoptosis of vascular endothelial cells was used to determine the protective effects of myricitrin. The levels of LDH, MDA and the activities of SOD, NO were measured using the respective kits. The H2O2-induced apoptosis of vascular endothelial cells was detected using MTT reduction, TUNEL assay, JC-1 and ROS staining. The activation of Caspase-3 was also measured by fluorometry. The expression of apoptosis-related proteins was determined with Western blotting assay. Myricitrin had significant protective effects against H2O2-induced apoptosis of vascular endothelial cells in a time- and dose-dependent manner. The results show that myricitrin could attenuate H2O2-induced decrease in the activities of SOD (P0.01). Myricitrin could decrease the levels of LDH, MDA and increase cell viability and the mitochondrial membrane potential (P0.01). Myricitrin had protective effects in a dose-dependent manner between 32 micromol x L(-1) to 64 micromol x L(-1). Myricitrin pretreatment could attenuate H2O2-induced increase of p-ERK. Moreover, myricitrin pretreatment could up-regulate the expression of the anti-apoptotic protein Bcl-2, down-regulate the expression of the pro-apoptotic protein Bax, and decrease the expression of Caspase-3, 9. In conclusion, myricitrin had significant protective effects against H2O2-induced apoptosis of vascular endothelial cells. Myricitrin can enhance the activities of anti-oxidative enzymes and decrease the production of free radicals. The possible mechanisms of action of myricitrin are due to myricitrin-mediated inhibition of phosphorylation of the apoptosis signaling pathways-related kinase ERK, up-regulation of the expression of the anti-apoptotic protein, and down-regulation of the expression of the pro-apoptotic protein.

Google map is a component for network map service developed by google company. It provides and discloses numerous API aimed at processing map operation. Based on the research of this technology, the article further explores and studies more service that it offers to various fields on the Internet and meanwhile displays the application of network map service by implementing a simple travelling navigation chart.

The JHKL' photometry and 2.3–4 μm spectrophotometry of some M giants, S type stars and carbon stars are presented in this paper. It is found that in combination with IRAS data, the energy spectra in 1–100 μm of S type stars are intermediate between those of M giants and carbon stars, which are obviously different. The spectrophotometry in the near infrared shows that, besides carbon stars, which have HCN and C2H2 strong absorptions at 3.1 μm, some S type stars have the similar but weaker absorption in the same spectral region. However, no trace of any absorption at 3.1 μm can be seen in M giants. These results probably provide more evidence for the M-S-C sequence in the late stage of stellar evolution.

23 carbon stars with IRAS LRS 2n, 3n and 6n are presented in this paper. Among them 7 samples have been identified to have 10 μm silicate features. It is found that on the IRAS color-color diagram most samples presented here are located in M star region or in the overlapping region of S-type stars and carbon stars. This means that the circumstellar shells of the stars are oxygen rich or are undergoing the stage of transition from the oxygen rich to the carbon rich. Observations of near infrared photometry and spectrophotometry indicate that the color distribution of stars presented here in the near infrared are the same as that of normal carbon stars. Furthermore, the stars observed all show deep absorption at 3.1μm caused by C2H2 and HCN. This means that central stars are really carbon rich. It is possible that the stars discussed in this paper are undergoing the evolutionary stage between oxygen rich M stars and normal carbon stars.

Based on IRAS photometric data, low resolution spectra, near-infrared photometric data, visible spectral features, main abundance ratios of MSC stars and physico-chemical processes taking place in their interior, we discuss their possible evolutionary states, pointing out that both the sequence M → S → C and the direct sequence M → C are possible.

To study the cause of weak expression of Ay antigens on the surface of erythrocytes and understand its molecular characteristics.Genotypic analysis of an individual of Ay serologic phenotype was performed using polymerase chain reaction with sequence specific primers (PCR-SSP). Sequence analysis of the 7 exons and some of the introns was carried out with ABI Prism 3100 DNA sequencer, and the Ay gene sequence was compared with A102 reference sequence.The genotype of the Ay individual was A102/101. Sequence analysis identified a nt467CT mutation, nt1009A/G heterozygosis and a nt517G-/C- deletion in the intron 5.The molecular genetic background of the Ay phenotype is polymorphic. Our findings are not sufficient to explain the cause of weak expression of Ay antigens on the surface of erythrocytes in this individual.

In the title molecule, C19H28O7S, the six-membered mannopyranoside and dioxane rings both display typical chair conformations. In the crystal structure, the hydroxy groups are involved in intermolecular hydrogen bonds, which link the molecules into chains extended along the b axis.

An investigation of short electromagnetic pulse (500 ps~500 ns) effects on some electronic ( microwave ) components, such as low noise amplifier(LNA), limiter, mixer, is summarized in this paper. Not only damage thresholds of some microwave components but also their regularities have been obtained by experiments and theoretic analyses. The relation of the threshold with pulse duration and rise time of the electromagnetic pulse were studied by changing the simulation pulse generatorpsilas output parameters. The features and the principle of microwave effects on microwave components are also discussed in this paper. The test data obtained in our study have been used to improve electro-magnetic compatibility for some microwave devices and systems.

To genotype the RHCE gene of Hans, Xinjiang's Uigurs and Kazakstans in China, and to compare the results of RHCE genotyping with that of RhCc/Ee phenotyping.RHCE genes of 98 Hans with RhD positive and 230 Hans, 72 Uigurs and 18 Kazakstans with RhD/RHD negative were genotyped with PCR-sequence specific primer (SSP) technique.The results of RHE/RHe genotyping from samples with RhD positive and negative were in accord with that of phenotyping. It would result in 4.44% error using C--G polymorphism at nt48 of RHCE gene to genotype RHCE, and 4.05% failure of detection using the 109 bp insertion to detectRHCE gene in Chinese Hans. The results of RHE/RHe genotyping in unrelated 72 Uigurs and 18 Kazakstans with RhD phenotype were consistent with that of phenotyping, and false positive and false negative were not found in genotyping in Uigurs and Kazakstans tested.The results of RHE/RHe and RHc genotyping were correct with PCR-SSP and accordant with that of phenotyping. Using the C48G polymorphism in exon 1 of RHCE to genotype RHC gene would result in false positive resulting from RHc mutation at this locus, and using the 109 bp insertion to genotype RHC gene would result in false negative because of the absence of the 109 bp. Therefore it is necessary to genotype RHC gene using more than two polymorphic loci.

A new radial three-cavity structure of the coaxial virtual cathode oscillator is proposed and studied numerically in this paper. Using the radial three-cavity structure, the beam-wave conversion efficiency is enhanced by modulating the E-field in the beam-wave interaction area, whereas the resonator composed of the radial three-cavity configuration and the mesh anode helps restrain mode competition efficiently. Also, the output microwave power is improved by the coaxial extraction structure in respect that it benefits the energy extraction and it can also absorb the used electrons entering into the drifting tube. With an electron beam of 400 kV and 50 kA, a peak instantaneous power about 6 GW is achieved by simulation at 4.14 GHz. The peak period-averaged power reaches 2.45 GW and the beam-wave conversion efficiency is about 12%. The output microwave has high mode purity and narrow bandwidth.