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PsKNN铁电单晶及其激光法生长

中国激光 2000年第9期27卷 842-846页

作者：蒋毅坚 R.Guo a.s.bhalla 北京工业大学国家产学研激光技术中心北京100022 宾夕法尼亚州立大学材料研究实验室

采用改进的激光加热基座法 (LHPG)生长出了位于准同形相界附近的含有 Pb元素的钨青铜结构的铁电晶体 (1- x) Pb2 KNb5O15- x sr2 Na Nb5O15(PsKNN)。通过调节激光功率和陶瓷源棒中 Pb O的含量 ,有效地控制和补偿了晶体生长过程中 Pb O... 详细信息

采用改进的激光加热基座法 (LHPG)生长出了位于准同形相界附近的含有 Pb元素的钨青铜结构的铁电晶体 (1- x) Pb2 KNb5O15- x sr2 Na Nb5O15(PsKNN)。通过调节激光功率和陶瓷源棒中 Pb O的含量 ,有效地控制和补偿了晶体生长过程中 Pb O的挥发。通过选择适当的籽晶 ,可以得到沿 [0 0 1],[10 0 ]和 [110 ]方向生长的 PsKNN晶体。研究了所生长晶体的铁电、介电和压电性质 ,并对其准同形相界进行了初步的讨论。

关键词： PsKNN 铁电单晶激光加热基座生长

Growth and dielectric properties of Ta2O5 single crystals grown by laser heated pedestal growth technique

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中国激光 2008年第11期35卷 1710-1712页

作者：蒋毅坚 Ruyan Guo A. s. bhalla Institute of Laser Engineering Beijing University of Technology Beijing 100124 Materials Research Laboratory The Pennsylvania State University University Park PA 16802 USA

Ta2O5 single crystals have been grown by the laser heated pedestal growth (LHPG) technique up to several centimeters length with diameter of 1.1 mm. The crystal, characterized by X-ray diffraction, dielectric measurement, and thermal expansion analysis, has Htri-Ta2O5 symmetry. Dielectric permittivity, loss tangent along [001] and [110] direction were investigated over the temperature range from -80 ℃ to 100 ℃. Large dielectric anisotropy in Ta2O5 single crystal was observed. At room temperature, the dielectric permittivities (1 MHz) along [001] and [110] are 33.2 and 231.9, respectively. The reason of dielectric enhancement in Ta2O5 crystal grown by LHPG was also discussed.

关键词：电介质单晶激光器生长技术

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Ta_2O_5单晶的激光法生长

应用激光 2002年第2期22卷 244-246页

作者：蒋毅坚 R.Guo a.s.bhalla 北京工业大学国家产学研激光技术中心 Materials Research Laboratory The Pennsylvania State UniversityPA 16802USA

采用激光加热基座生长法(LHPG)生长出Ta_2O_5单晶,测量了所生长晶体的介电系数和介电损耗随晶格方向的关系。Ta_2O_5晶体表现出很强的介电各向异性,并且其介电系数的平均值比 Ta_2O_5陶瓷的大许多。Ta_2O_5单晶的成功生长证明了LHPG技... 详细信息

采用激光加热基座生长法(LHPG)生长出Ta_2O_5单晶,测量了所生长晶体的介电系数和介电损耗随晶格方向的关系。Ta_2O_5晶体表现出很强的介电各向异性,并且其介电系数的平均值比 Ta_2O_5陶瓷的大许多。Ta_2O_5单晶的成功生长证明了LHPG技术在生长高熔点晶体方面所具有的独特能力,同时也表明它作为一种特殊的激光材料加工技术在材料科学与工程中将发挥重要作用。

关键词：激光加热基座生长法 Ta205单晶介电性质介电损耗晶格方向 LHPG技术激光材料加工技术介电材料五氧化二钽

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四硼酸锂单晶的热电和压电性能

压电与声光 1987年第4期10卷 76-79页

作者： a.s.bhalla 胡少勤美.宾夕法尼亚州立大学材料研究室

在50—-150℃的温度范围内测量了Li_2B_4O_7(LTB)单晶的热电、压电和介电性能.室温时,LTB的介电常数K_3约为10(100kHz),介电tgδ约为1(10kHz),液氮温度下,tgδ降到～10^(-3),室温时测得的热电系数约为-30μC/m^2·K,而当温度为-150℃时... 详细信息

在50—-150℃的温度范围内测量了Li_2B_4O_7(LTB)单晶的热电、压电和介电性能.室温时,LTB的介电常数K_3约为10(100kHz),介电tgδ约为1(10kHz),液氮温度下,tgδ降到～10^(-3),室温时测得的热电系数约为-30μC/m^2·K,而当温度为-150℃时,热电系数增至-120μC/m^2·K,并显示出能与室温下获得的TGs的值相媲美的热电品质因素p/K值,测量结果表明,Li_2B_4O_7的一次和二次热电分量为独立分量,其一次效应对热电效应起主要作用.压电测量表明,Li_2B_4O_7的g_(33)值((?)270×10^(-3)V·m/N)和g_h值((?)100×10^(-3)V·m/N)大,预示着Li_2B_4O_7在压力传感器领域的应用前景.

关键词：热电效应热电 LTB 电性热电系数热电性能介电常数电容率介电性质单晶晶形方硼石硼酸盐矿物

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激光加热基座生长晶体技术的新进展

激光与光电子学进展 2001年第9期38卷 55-55页

作者：蒋毅坚 R.G.Guo a.s.bhalla 北京工业大学激光工程研究院 Materials Research Laboratory The Pennsylvania St

介绍了激光加热基座生长晶体技术(LHPG)的特色和最新进展.具体表现在:1) 所生长晶体的尺寸大幅度提高,横截面直径由0.5 mm左右提高到2.5 mm.运用该项技术,成功地进行了人工蓝宝石晶体的生长,并应用于装饰性人工宝石的生产过程中.对直径... 详细信息

介绍了激光加热基座生长晶体技术(LHPG)的特色和最新进展.具体表现在:1) 所生长晶体的尺寸大幅度提高,横截面直径由0.5 mm左右提高到2.5 mm.运用该项技术,成功地进行了人工蓝宝石晶体的生长,并应用于装饰性人工宝石的生产过程中.对直径大于1.0 mm的铁电晶体,已可以系统测量其介电、压电、热释电、热膨胀性质以及电滞回线.2) 通过对LHPG生长装置的改进,使晶体生长的速度大幅提高.莫来石晶体的生长速度可达150 mm/小时.3) 通过对陶瓷源棒组分的调整和对生长温度、气氛的控制,成功地生长出了含有铅元素的晶体PsKNN和PMN-PT,使该方法在开发新型高性能压电换能器和电光器件方面将发挥重要作用.4) 实现了几种晶体共生于一体的共晶型晶体的生长,如微波介电材料MgTiO3-CaTiO3,大大拓宽了该方法的应用领域.5) 成功地生长出Ba(Mg1/3Ta2/3)O3晶体,使晶体生长温度提高到3100°C.(OH9)

关键词：晶体生长介电材料激光加热

Detection and clearance in Alzheimer’s disease: leading with illusive chemical, structural and morphological features of the targets

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Neural Regeneration Research 2024年第3期19卷 497-498页

作者： Luís Gales i3s−Instituto de Investigação e Inovação em saúde Rua Alfredo AllenPortoPortugal(Gales L)IBMC−Instituto de Biologia Molecular e CelularUniversidade do PortoRua Alfredo AllenPortoPortugal ICBAs−Instituto de Ciências Biomédicas Abel salazar Rua de Jorge Viterbo FerreiraPortoPortugal

Highly specific interactions between biomolecules,such as antigen-antibody,protein-ligand,or nucleic acid base pair complementary are on the basis of the organization of complex *** same principles may be tentatively used in molecular medicine for diagnosis and therapeutics.A molecule can be designed to selectively bind a protease and thereby inhibit the production of a peptide that forms toxic aggregates in the brain or an antibody may be produced to bind specifically to that peptide for detection or clearance ***,interference in biological systems is not that *** a start there is the inhibition of the physiological role of the protease;moreover,several cleavage fragments may be produced,which may continue to diverge due to putative post-translational modification and self-assembly processes,hiding the toxic target in a“soup”of peptide species varying in size,structure and chemical composition.A perspective of the current status and challenges in targeting peptide species for diagnosis and treatment in the context of Alzheimer’s disease is given.

关键词： Alzheimer diagnosis thereby

Model dependent analysis of D^(+)_(s)→η^(′)l+v_(l) decays in beyond standard model

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Chinese Physics C 2024年第9期48卷 82-95页

作者： s.Mahata M.Mandal H.Mahapatra s.Biswas s.sahoo Department of Physics National Institute of Technology Durgapur Durgapur 713209West BengalIndia

Motivated by the recent experimental results of branching fractions for D^(+)_(s)→η^(′)l+v_(l) decays,which deviate from their sM predictions,we hve investigated these decays in W' model and scalar leptoquark model to determine potential signatures of new physics(NP) in semileptonic charm decays induced by c→(s,d)l+v_(l) *** recent experimental results of branching fractions for semileptonic D meson decays,new coupling parameters are predicted for the aforementioned NP *** fraction,forward-backward asymmetry,and lepton polarization asymmetry are examined by considering the predicted NP coupling *** results of branching fractions in scalar leptoquark model are found very close to the experimental results and exist around the range of 1σ *** presented a comparative study of the NP models to check their sensitivity on these *** anticipate that further research on these decays will significantly support our findings.

关键词： charm decay new physics W′boson scalar leptoquark flavour changing charged current

Characterization of tumors of jaw:Additive value of contrast enhancement and dual-energy computed tomography

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World Journal of Radiology 2024年第4期16卷 82-93页

作者： Deepak Justine Viswanathan Ashu seith bhalla smita Manchanda Ajoy Roychoudhury Deepika Mishra Asit Ranjan Mridha Department of Radiodiagnosis and Interventional Radiology All India Institute of Medical SciencesNew Delhi 110029India Department of Oral and Maxillofacial surgery All India Institute of Medical SciencesNew Delhi 110029India Department of Oral Pathology and Microbiology All India Institute of Medical SciencesNew Delhi 110029India Department of Pathology All India Institute of Medical SciencesAnsari NagarNew Delhi 110029India

BACKGROUND Currently,the differentiation of jaw tumors is mainly based on the lesion’s morphology rather than the enhancement characteristics,which are important in the differentiation of neoplasms across the *** is a paucity of literature on the enhancement characteristics of jaw *** is mainly because,even though computed tomography(CT)is used to evaluate these lesions,they are often imaged without intravenous *** study hypothesised that the enhancement characteristics of the solid component of jaw tumors can aid in the differentiation of these lesions in addition to their morphology by dual-energy CT,therefore improving the ability to differentiate between various *** To evaluate the role of contrast enhancement and dual-energy quantitative parameters in CT in the differentiation of jaw *** Fifty-seven patients with jaw tumors underwent contrast-enhanced dual-energy *** analysis of the tumor,including the enhancing solid component,was done,followed by quantitative analysis of iodine concentration(IC),water concentration(WC),HU,and normalized *** study population was divided into four subgroups based on histopathological analysis-central giant cell granuloma(CGCG),ameloblastoma,odontogenic keratocyst(OKC),and other jaw tumors.A one-way ANOVA test for parametric variables and the Kruskal-Wallis test for nonparametric variables were *** significant differences were found,a series of independent t-tests or Mann-Whitney U tests were *** Ameloblastoma was the most common pathology(n=20),followed by CGCG(n=11)and *** showed a higher mean concentration of all quantitative parameters than ameloblastomas(Pshold of 31.35×100μg/cm^(3) had the maximum sensitivity(81.8%)and specificity(65%).Between ameloblastomas and OKC,the former showed a higher mean concentration of all quantitative parameters(Pstomas with OKCs,the latter showed

关键词： Jaw neoplasms Ameloblastomas Dual-energy computed tomography Iodine quantification Mandibular neoplasms Maxillary neoplasms

Astrophysical s-factor and reaction rate for 15N(p,γ)16O within the modified potential cluster model

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Chinese Physics C 2024年第4期48卷 130-145页

作者： s.B.Dubovichenko A.s.Tkachenko R.Ya.Kezerashvili N.A.Burkova B.M.Yeleusheva Fesenkov Astrophysical Institute 050020 AlmatyKazakhstan New York City College of Technology City University of New YorkBrooklyn11201 New YorkUSA Graduate school and University Center City University of New York10016 New YorkUSA al-Farabi Kazakh National University 050040 AlmatyKazakhstan

We study radiative p^(15)N capture on the ground state of ^(16)O at stellar energies within the framework of a modified potential cluster model(MPCM)with forbidden states,including low-lying *** investigation of the ^(15)N(p,γ0)^(16)O reaction includes the consideration of ^(3)s_(1) resonances due to E1 transitions and the contribution of the ^(3)P_(1) scattering wave in the p+^(15)N channel due to the ^(3)P_(1)→^(3)P_(0)M1 *** calculated the astrophysical low-energy s-factor,and the extrapolated s(0)turned out to be within 34.7−40.4 keV·*** important role of the asymptotic constant(AC)for the ^(15)N(p,γ0)16O process with interfering ^(3)s_(1)(312)and ^(3)s_(1)(962)resonances is elucidated.A comparison of our calculation for the s-factor with existing experimental and theoretical data is addressed,and a reasonable agreement is *** reaction rate is calculated and compared with the existing *** has negligible dependence on the variation of AC but shows a strong impact of the interference of ^(3)s_(1)(312)and ^(3)s_(1)(962)resonances in reference to the CNO Gamow windows,especially at low *** estimate the contribution of cascade transitions to the reaction rate based on the exclusive experimental data from ***.C.85,065810(2012).The reaction rate enhancement due to the cascade transitions is observed from T_(9)>0.3 and reaches the maximum factor~1.3 at T_(9)=*** present the Gamow energy window and a comparison of rates for radiative proton capture reactions ^(12)N(p,γ)^(13)O,^(13)N(p,γ)^(14)O,^(14)N(p,γ)^(15)O,and ^(15)N(p,γ)^(16)O obtained in the framework of the MPCM and provide the temperature windows,prevalence,and significance of each process.

关键词： low and astrophysical energies p^(15)N system thermonuclear reaction rate potential cluster model CNO-cycle