Low noise,continuous-wave single-frequency 1.5-μm laser generated by a singly resonant optical parametric oscillator

We report a low noise continuous-wave （CW） single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator （SRO） based on periodically poled lithium niobate （PPLN）. The SRO was pumped by a CW single-frequency Nd：YVO4 laser at 1.06μm. The 1.02 W of CW single-frequency signal laser at 1.5 μm was obtained at pump power of 6 W. At the output power of around 0.75 W, the power stability was better than ±l.5% and no mode-hopping was observed in 30 min and frequency stability was better than 8.5 MHz in 1 min. The signal wavelength could be tuned from 1.57 to 1.59 μm by varying the PPLN temperature. The 1.5-μm laser exhibits low noise characteristics, the intensity noise of the laser reaches the shot noise limit （SNL） at an analysis frequency of 4 MHz and the phase noise is less than 1 dB above the SNL at analysis frequencies above 10 MHz.

Paramagnetic Anisotropy of CdGd_2(WO_4)_(4-δ) Single Crystal

CdGd2 （WO4）4 -δ single crystal was grown using the Czochralski＇s method. The crystal structure was tetragonal seheelite with lattice parameters a = b = 0.5203 nm and c = 1. 1359 nm. There were vacancies of （WO4）^2- , therefore, there were some Gd^2＋ ions. Langevin paramagnetism and anisotropy were observed from the δ-T curves at room temperature. The susceptibility X//was 3.5018×10^-3, and X⊥ was 3.4403× 10^-2. The anisotropy was also observed in the electron spin resonance （ESR） experiments. The anisotropic Land6 factors were g//= 2. 1333 and g~ = 2. 8411. The direction of easy magnetization was in the α-b plane. Anisotropic paramagnetic Curie constants C//and C⊥ were not only related to macroscopic a that was observed through the experiment, but were also related to J⊥ and J//, which were the microscopic quantum numbers of the Gd^2＋ and Gd^3｜ ions. Based on the detailed analyses, the proportion of 36.8% of Gd^3＋ ions to 63.2% of Gd^2＋ ions in the Gd ions of the CdGd2（WO4）4-δ crystal was calculated, and δ was 0.638 in the single crystal.

Synthesis and Structure of Large Single Crystal of TPAF-AlPO_4-5 Molecular Sieve

A large single crystal of TPAF-AlPO4-5 molecular sieve was synthesized by hydrothermal crystallization in the presence of ammonium fluoride. Starting material composition was · 1 P2O5 · 1 Al2O3 · 2. 2 TPAOH · 1. 7 NH4F ·318 H2O. The crystal size has a hexagonal prism with 80μm across and 500μm length.The structure of tetrapropylarnmonium fluoride - aluminium phosphate type-5 was investigated with X-ray diffraction. The unit cell composition is 12AlPO4 · TPAF, space group P6cc (a= 13. 740(5), c= 8. 474(4) A ). Average bond distances are: P-O 1. 564A and Al-O 1. 640A ,which may be due to the partial disorder of the arrangement of P, Al in the framework. The angles of O-T-O and T-O-T (T?P, Al) are 102-116° and 148-176°, respectively. Residue electron density was not well enough defined to give a precise position for tetrapropylammonium fluoride (TPAF). The template agent, TPA+ cations, situate in the 12-ring channels and F- anions locate in double 4-rings near the 12-ring channels. Fixing atomic positions for the TPAF reduced the unweighted and weighted R, R, from 0. 063 and 0. 082 to 0. 046 and 0. 042,respectively.

A new integration algorithm for finite deformation of thermo-elasto-viscoplastic single crystals

An algorithm for integrating the constitutive equations in thermal framework is presented, in which the plastic deformation gradient is chosen as the integration variable. Compared with the classic algorithm, a key feature of this new approach is that it can describe the finite deformation of crystals under thermal conditions. The obtained plastic deformation gradient contains not only plastic defor- mation but also thermal effects. The governing equation for the plastic deformation gradient is obtained based on ther- mal multiplicative decomposition of the total deformation gradient. An implicit method is used to integrate this evo- lution equation to ensure stability. Single crystal 1 100 aluminum is investigated to demonstrate practical applications of the model. The effects of anisotropic properties, time step, strain rate and temperature are calculated using this integration model.

Transportable Identity Construction in Single Mother Family

This paper studies single-parent family conversation mainly,the researcher takes 10 hours of recordings in a single-parent family in Shenzhen as data to study conversational identity construction.

The effects of Er^(3+) ion concentration on 2.0-μm emission performance in Ho^(3+)/Tm^(3+) co-doped Na_(5)Y_(9)F_(32) single crystal under 800-nm excitation

Na_(5)Y_(9)F_(32) single crystals doped with ~0.8-mol% Ho^(3+),~1-mol% Tm^(3+),and various Er^(3+) ion concentrations were prepared by a modified Bridgman method.The effects of Er^(3+)ion concentration on 2.0-μm emission excited by an800-nm laser diode were investigated with the help of their spectroscopic properties.The intensity of 2.0-μm emission reached to maximum when the Er^(3+) ion concentration was ~1 mol%.The energy transfer mechanisms between Er^(3+),Ho^(3+),and Tm^(3+) ions were identified from the change of the absorption spectra,the emission spectra,and the measured decay curves.The maximum 2.0-μm emission cross section of the Er^(3+)/Ho^(3+)/Tm^(3+)tri-doped Na_(5)Y_(9)F_(32) single crystal reached 5.26 × 10^(-21) cm^(2).The gain cross section spectra were calculated according to the absorption and emission cross section spectra.The cross section for ~2.0-μm emission became a positive gain once the inversion level of population was reached 30%.The energy transfer efficiency was further increased by 11.81% through the incorporation of Er^(3+) ion into Ho^(3+)/Tm^(3+) system estimated from the measured lifetimes of Ho^(3+)/Tm^(3+)-and Er^(3+)/Ho^(3+)/Tm^(3+)-doped Na_(5)Y_(9)F_(32)single crystals.The present results illustrated that the Er^(3+)/Ho^(3+)/Tm^(3+)tri-doped Na_(5)Y_(9)F_(32) single crystals can be used as promising candidate for 2.0-μm laser.

Study of Single Plated Principle on Large Diameter Circular Weft Knitting Machine

A new theory and method that differs from the tradition-al single plated weft - knitting theory and method hasbeen expounded after theoretical analyzing and experi-mental proving. If the new method is used when platingstitch is knitted on large diameter weft knitting machine,the thorny problem of long standing that ground yarn iseasy to appear on the face side of fabric is solved. Thenew method, i.e, the production of physical ability oftraining uniform for serviceman has been used.

大球盖菇母种培养基配方筛选研究

[目的]筛选适宜的大球盖菇母种培养基。[方法]先进行单因素试验筛选最适宜碳源、氮源和无机盐,并在此基础上进行正交试验。[结果]单因素结果显示,大球盖菇最适宜碳源为麦芽糖,最适宜氮源为硝酸铵,最适宜无机盐为磷酸二氢钾。[结论]正交试验结果表明最佳培养基配方为马铃薯200 g、麦芽糖20 g、硝酸铵0.5 g、磷酸二氢钾0.5 g、琼脂20 g、水1000 mL。

基于联合有限元-离散元的混凝土重力坝破坏三维仿真模拟

水利工程中混凝土重力坝在地震等作用下的三维破坏形式以及破坏过程对大坝安全影响重大。本文建立了固体材料的联合有限元-离散元(Combined Finite-Discrete Element)三维数学模型,并引入Single/Smeared断裂损伤模型,模拟混凝土材料的破坏。数学模型经验证后,用于地震作用下混凝土重力坝破坏的三维数值模拟,结果表明,联合有限元-离散元方法能够有效模拟坝体的破坏模式和破坏阈值条件,且具有将坝体连续变形与不连续断裂有机结合的优点。通过一系列数值模拟工况的对比,分析了模型网格分辨率对破坏条件、破坏模式以及程序计算效率的影响,研究结果能够为大坝的抗震设计提供有价值的参考。

MODELING THE STRESS-STRAIN CURVES UNDER DYNAMIC RECRYSTALLIZATION

An analytical model for dynamic recrystallization (DRX) is studied based on the relative grain size model proposed by Sakai and Jonas, and the characteristic flow behaviors under DRX are analyzed and simulated. Introducing the variation of dynamic grain size and the heterogeneous distribution of disolo- cation densities densities under DRX,a simple method for modeling and simulating DRX processes is developed by using Laplace transformation theory. The results derived from the present model agree well with the experimental results in literatures. This simulation can reproduce a number of features in DRX flow behaviors, for example,single and multiple peak flow behaviors followed by a steady state flow, the transition between them, and so on.

Interleukin-6-174G/C polymorphism is associated with a decreased risk of type 2 diabetes in patients with chronic hepatitis C virus

BACKGROUND Chronic hepatitis C(CHC)is associated with type 2 diabetes mellitus.Although the pathogenesis remains to be elucidated,a growing evidence has suggested a role of pro-inflammatory immune response.Increased serum concentrations of Interleukin 6(IL-6)have been associated with insulin resistance,type 2 diabetes mellitus as well as advanced forms of liver disease in chronic hepatitis C infection.AIM To investigate the frequency of IL-6-174G/C(rs1800795)single nucleotide polymorphism(SNP)in CHC patients and in healthy subjects of the same ethnicity.Associations between type 2 diabetes mellitus(dependent variable)and demographic,clinical,nutritional,virological and,IL-6 genotyping data were also investigated in CHC patients.METHODS Two hundred and forty-five patients with CHC and 179 healthy control subjects(blood donors)were prospectively included.Type 2 diabetes mellitus was diagnosed according to the criteria of the American Diabetes Association.Clinical,biochemical,histological and radiological methods were used for the diagnosis of the liver disease.IL-6 polymorphism was evaluated by Taqman SNP genotyping assay.The data were analysed by logistic regression models.RESULTS Type 2 diabetes mellitus,blood hypertension and liver cirrhosis were observed in 20.8%(51/245),40.0%(98/245)and 38.4%(94/245)of the patients,respectively.The frequency of the studied IL-6 SNP did not differ between the CHC patients and controls(P=0.81)and all alleles were in Hardy-Weinberg equilibrium(P=0.38).In the multivariate analysis,type 2 diabetes mellitus was inversely associated with GC and CC genotypes of IL-6-174(OR=0.42;95%CI=0.22-0.78;P=0.006)and positively associated with blood hypertension(OR=5.56;95%CI=2.79-11.09;P<0.001).CONCLUSION This study was the first to show that GC and CC genotypes of IL-6-174 SNP are associated with a decreased risk of type 2 diabetes mellitus in patients chronically infected with hepatitis C virus.The identification of potential inflammatory mediators involved in the crosstalk between hepatitis C virus and the axis pancreas-liver remains important issues that deserve further investigations.

Genetic variation of TGF-BR2 as a protective genotype for the development of colorectal cancer in men

BACKGROUND The role of transforming growth factor beta(TGF-β)signaling,including both the cytokine and their receptors,in the etiology of colorectal cancer(CRC)has been of particular interest lately.AIM To investigate the association between promoter polymorphism in TGF-β receptor 2 TGF-BR2G^([-875])A with a CRC risk in a cohort of Bulgarian patients using a casecontrol gene association study approach,as well as the protein levels of TGF-β1 in the peripheral blood.METHODS A cohort of 184 CRC patients and 307 sex and age-matched healthy subjects were recruited in the study.A genotyping of the TGF-BR2G^([-875])A(rs3087465)polymorphism was performed by primer-introduced restriction analysespolymerase chain reaction approaches.RESULTS The frequency of TGF-BR2G^([-875])A genotype was decreased in male patients with CRC than in healthy men(31.3%vs 44.8%;P=0.058).Among males,the TGF-BR2G[-509]G genotype was related to a significantly increased risk of CRC development(OR=1.820,95%CI:0.985-3.362,P=0.055)than the GA+AA genotype.Also,TGF-BR2^([-875])*A-allele itself was rarer in men with CRC than healthy men(19.1%vs 26.9%,P=0.086)and was associated with a protective effect(OR=0.644;95%CI:0.389-1.066;P=0.086).Regarding the genotypes,we found that TGF-β1 serum levels were higher in GG genotype in healthy persons above 50 years than the CRC patients[36.3 ng/mL interquartile range(IQR)19.9-56.5 vs 22.4 ng/mL IQR 14.8-29.7,P=0.014].We found significant differences between higher levels of TGF-β1 serum levels in healthy controls above 50 years(GG genotype)and CRC patients(GG genotype)at the early stage(36.3 ng/mL IQR 19.9-56.5 vs 22.8 ng/mL IQR 14.6-28.6,P=0.037)and advanced CRC(36.3 ng/mL IQR 19.9-56.5 vs 21.6 ng/mL IQR 15.9-33.9,P=0.039).CONCLUSION In summary,our results demonstrated that TGF-BR2 AG and AA genotypes were associated with a reduced risk of CRC,as well as circulating levels of TGF-βcould prevent CRC development in a gender-specific manner.Notably,male carriers of TGF-BR2-875A allele genotypes had a lower risk of CRC development and progression,suggesting that TGF-BR2-875A/G polymorphism significantly affects the protective biological factors that also impact the risk of colon and rectal carcinogenesis.

Synthesis,Characterization,X-ray Crystal Structure and Safener Activity of Chiral 2-(3-Methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-oxoethyl Acetate

The new title compound, chiral 2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）- 2-oxoethyl acetate, has been synthesized via reduction, cyclization and acylation reaction. The structure of the product has been confirmed by IR, 1H NMR, 13C NMR, LC-MS （ESI） and single-crystal X-ray diffraction. （R）-2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）-2-oxoethyl acetate crystallizes in monoclinic, space group P21/c with a = 11.867（2）, b = 8.4087（2）, c = 14.325（6） A^°, β = 117.59（2）°, Z = 4, V = 1266.9（6） A^°3, Dc = 1.307 g/cm^3, F（000） = 528, μ（MoKα） = 0.097 mm-1, R = 0.0453 and wR = 0.1237; （S）-2-（3-methyl-2,3-dihydrobenzo[b][1,4]oxazin-4-yl）-2-oxoethyl acetate belongs to the triclinic system, space group P with a = 8.2647（17）, b = 8.7034（17）, c = 9.5479（19） A^°, α = 105.33（3）, β = 100.95（3）, γ = 105.14（3）°, Z = 2, V = 614.1（2） A^°3, Dc = 1.348 g/cm^3, F（000） = 264, μ（MoKα） = 0.10 mm-1, R = 0.0613 and wR = 0.1037. Both of the molecules prefer to form crystal packing through C–H…O hydrogen bonds.

Synthesis,Crystal Structure and Fluorescence Property of N-n-butyl-4-[di(bromoethyl)]amino-1,8-naphthalimide

The halogen as a kind of alkylating reagent is used to introduce new group to realize the fluorescence sensors efficient of metal ion detection. The substituent at C-4 position was double bromine, which defined that the halogen as an alkylating reagent should be further researched and detected for Hg2＋. Therefore, the N-n-butyl-4-[di（bromoethyl）]amino-1,8-naphthalimide has been synthesized to detect some metal ions. The title compound has been prepared via substitute reaction and was characterized by IR, 1H NMR, 13 C NMR, and MS. It crystallizes in triclinic, space group P1 with a = 9.0071（18）, b = 9.804（2）, c = 13.073（3）A, α = 73.17（3）, β = 71.73（3）, γ = 62.95（3）°, Z = 2, V = 961.5（3） A3, Dc = 1.666 g/cm3, F（000） = 484, μ（Mo Kα） = 4.232 mm-1, R = 0.0429 and w R = 0.1004. The presence of intermolecular hydrogen bonds as well as π-π stacking interaction led to the stability of the compound. The fluorescence intensity was obviously lower than that of other ions when Hg2＋ was added with the concentration of 1 × 10^-5 mol·L-1.

The Protective Effects of N-Acetylcysteine on Exogenous Hydrogen Peroxide and Endogenous Superoxide Anion-induced DNA Strand Breakage in Human Spermatozoa

Objective To explore the protective effects of N Acetylcysteine (NAC) on exogenous hydrogen peroxide and endogenous superoxide anion induced DNA strand breakage in human spermatozoa by using the single cell gel electropherosis (SCGE) Methods Sperm cells were exposed to 0.5 mmol/L of H 2O 2 or 5.0 mmol/L of β NADPH with or without 0.1, 0.5, 1.0 mmol/L of NAC. The percentage of sperm comet cells and the comet tail lengths were measured in the treated sperm cells by using SCGE. Results Both percentage of comet sperm nuclei and mean tail length in sperm cells exposed to 0.5 mmol/L hydrogen peroxide with different concentrations of NAC decrease significantly in a dose dependent manner as compared with sperm cells exposed to H 2O 2 without NAC or catalase. Although mean tail length in sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC decreases significantly compared with sperm cells exposed to β NADPH without NAC or SOD, there were no significant differences on the percentage of sperm comet cells between sperm cells exposed to 5.0 mmol/L of β NADPH with different concentrations of NAC and sperm cells exposed to 5.0 mmol/L of β NADPH without NAC. Conclusion NAC has a protective effect on exogenous hydrogen peroxide induced DNA damage, while protective effect of NAC against O - 2 induced DNA strand breakage is significant but very weak.

Associations between IL-1RN variable number of tandem repeat, IL-1β (-511) and IL-1β (+3954) gene polymorphisms and urolithiasis in Uighur children of China

Objective:Interleukin-1(IL-1)is a pro-inflammatory cytokine which may be related to urolithiasis.Genetic polymorphisms of the interleukin-1beta(IL-1β)have been proposed as markers for urolithiasis in some areas.Due to the high incidence of urolithiasis in Uighur children(Xinjiang,China)and existence of ethnic difference,our aim is to explore the potential of IL-1 gene polymorphisms and urolithiasis among these children.Methods:Genomic DNA extracted from peripheral blood of 115 patients and 98 controls were used for genotype polymorphisms analyses.IL-1 receptor antagonist(IL-1RN)gene variable number of tandem repeat(VNTR)gene polymorphisms were analyzed by PCR method.PCR-based restriction analysis was done for the IL-1β(-511)and IL-1β(+3954)gene polymorphisms by endonucleases Ava I and Taq I,respectively.The genotype distribution,allele frequencies,carriage rate,and haplotype frequencies were statistically analyzed.Results:No significant differences were observed in genotypic frequencies between pediatric urolithiasis patients and control group for IL-1RN gene(χ^(2)=1.906,p=0.605),IL-1β(-511)gene(χ^(2)=0.105,p=0.949),or IL-1β(+3954)gene(χ^(2)=3.635,p=0.169).There were yet no significant differences of the allele frequencies of IL-1RN VNTR gene(p=0.779),IL-1β(-511)gene(p=0.941),and IL-1β(+3954)gene(p=0.418)in the case and control groups,as well as the carriage rate and haplotype of them(all p>0.05).Conclusions:The associations between IL-1RN VNTR,IL-1β(-511)and IL-1β(+3954)genes polymorphisms and urolithiasis were not significant in Uighur children.The results need to be confirmed in studies with larger population sample size,as well as in other ethnic groups.

社工介入失独母亲扶助机制及优化反思——以广州市“玫瑰计划”为例

失独群体数量日益增大,亟待社会各界关注。失去孩子对于一个母亲来说是致命的打击,主要表现为生活困境、心理精神困境、社会关系困境和个人发展困境。社会工作者凭借其独特的优势可以有效帮助失独母亲走出伤痛,恢复正常生活,并最终实现人生价值。以广州市“玫瑰计划”(广州市首个社工介入失独母亲扶助项目)为案例,从目标、人员、资源和策略维度分析社工介入失独母亲扶助机制,基于实践反思优化,社工介入失独母亲扶助机制还需要在服务人员、服务内容、服务方式和服务态度进一步完善。

Tm^(3+) and Nd^(3+) singly doped LiYF_4 single crystals with 3-5 μm mid-infrared luminescence

Mid-infrared（MIR） emissions of 2.4 and 3.5 μm from Tm3＋：LiYF4 single crystals attributed to3H4 →3H5 and3H5 →3F4 transitions as well as MIR emissions of 4.2,4.3,and 4.5 μm from Nd3＋：LiYF4 lasers attributed to4I15/2 →4I13/2,4I13/2 →4I11/2,and4I11/2 →4I9/2 transitions,respectively,are observed.LiYF4 single crystals possess high transmittance of over 85% in the 2.5-6 μm range.The large emission crosssections of Tm-doped crystals at 2.4 μm（1.9×10-20cm2） and Nd-doped crystals at 4.2 μm（0.84×10-20 cm2） as well as the high rare-earth doping concentrations,excellent optical transmission,and chemicalphysical properties of the resultant samples indicate that Nd3＋and Tm3＋singly doped crystals may be promising materials for application in MIR lasers.

Study on Growth of GdBaSrCu_3O_(7-δ) Single Crystal

1 Results It is generally known that CuO2 planes of layered cuprate superconductors play a major role on the variation of critical temperature,Tc.In order to investigate their microscopic and electronic properties,preparation of such materials in single crystal form with highly structure orientation is very important.Crystal growth techniques for copper oxide materials have greatly improved since the discovery of high Tc superconductor materials[1].However,a strong reaction between CuO flux and crucible...

本舰机动左右舷分辨方法研究

针对传统单根线列阵的左右舷分辩问题,经过深入分析,给出了本舰机动左右舷分辨方法中的一些影响因素,并对机动角度和滞后时间得出了定量结论。文中研究的内容对传统拖曳线列阵声纳的左右舷分辨和战术使用具有参考价值。