产前超声对孕11-13周+6胎儿肢体畸形的诊断价值分析

目的:观察孕11-13+6周产前超声检查在诊断胎儿肢体畸形的意义。方法:以2015年1月1日-2017年12月31日入院行孕检的2013例孕妇为本次观察对象,所有孕妇给予行规范化超声检查,测胎儿NT厚度,观察胎儿肢体结构、形态等情况,对早期检查异常者并给予引产者行X线检查,对于继续妊娠者追踪妊娠结局,观察中期超声检查结果。结果:孕早期检出7例,误诊1例、漏诊3例,孕中期检出2例,孕11-13+6周检出率为66.6%,9例异常胎儿其中2例NT出现异常,所占比例为22.2%。结论:胎儿肢体畸形在孕11-13+6周行超声检查检出率较高。     

孕早期超声筛查对胎儿先天性心脏病的评估作用

目的：探讨分析孕早期超声筛查对胎儿先天性心脏病的评估作用。方法：选取2020年6月至2023年6月我院接收的行产前检查的500例孕妇作为研究对象,所有孕妇均接受孕早期胎儿超声筛查,并随访了解最终确诊结果（新生儿超声/尸检）,对孕早期超声筛查在胎儿先天性心脏病中的评估作用进行观察分析。结果：孕11-13+6周,显示成功率最高的切面为胎儿四腔心切面,其后依次为左室流出道切面、右室流出道切面、三血管切面;孕13+6周各切面显示成功率较孕11周、孕12周明显更高（P<0.05）。胎儿心脏超声筛查与最终确诊结果相比无明显差异（P>0.05）。超声诊断准确11例,其中法洛四联症比例最高,占比30.77%;其次为右心室发育不良和心内膜垫缺损,占比均为15.38%;诊断准确率为99.40%、灵敏度为84.62%、特异度为99.79%。结论：孕早期超声筛查能早期显示胎儿心脏畸形,诊断准确率、灵敏度、特异度高,对胎儿先天性心脏病的评估价值高。     

NT超声检查在早孕期胎儿筛查中的临床价值观察

目的:探究颈项透明层厚(NT)超声检查在早孕期胎儿筛查中的临床价值。方法:研究对象为2018年5月-2020年11月在本院500例孕11-13⁺⁶周孕妇,采用超声对胎儿颈项透明层厚进行评估测量,并将其测量结果同随访结果进行对比。结果:500例孕产妇中,仅NT≥2.5 mm者16例,其中14例正常胎儿,1例至中孕期胎死宫中,1例异常胎儿引产;NT≥2.5 mm合并其他异常4例,均引产;NT<2.5 mm合并超声软指标2例,均正常分娩。结论:早孕期NT超声检查可以有效筛查胎儿异常,对胎儿预后评价有指导意义,此方法值得应用与推广。     

彩色超声筛查法对产前胎儿神经系统畸形的诊断价值分析

目的:研究彩色超声筛查法对产前胎儿神经系统畸形的诊断价值。方法:选取2015年9月-2016年9月于我院进行体检的1030例孕妇临床资料予以研究,产前所有孕妇均进行彩色超声筛查,同时将产后诊断结果与筛查进行比对,探查超声诊断的胎儿畸形率。结果:彩超检查脑膜或脑部膨出、无脑、全前脑、脊柱裂以及脑积水的畸形类比分别为10.00%、23.75%、5.00%、18.75%、42.50%,对照产后结果其诊断符合率高达100.00%,而且早中孕期联合的检出率最高为100.00%,早孕期的检出率最低为63.75%。结论:彩超筛查在产前胎儿神经系统畸形诊断中检出率较高,具有重要价值。     

超声检查胎儿颈项透明层厚度在筛查胎儿染色体异常中的价值

目的:探析超声检查应用在胎儿颈项透明层厚度中对筛查胎儿染色体异常的临床价值。方法:在2015年5月至2017年5月我院接收的孕11周-13周超声胎儿NT孕妇中选取胎儿NT不低于2.5mm的孕妇59例作为本次研究的对象。结果:染色体核型:54例行胎儿染色体核型分析孕妇中,44例染色体核型无异常;染色体数目异常10例,异常检出率为18.52%。结论:在孕11周至13周期间实施超声诊断胎儿NT增厚,能够明确染色体异常的情况,还有利于了解胎儿其他的结构畸形,值得推广。     

探讨孕中期血清学产前超声检测联合筛查的应用效果

目的:研究血清学筛查联合超声在孕中期异常胎儿检查中的临床疗效。方法:对2796例孕中期孕妇进行血清学与超声筛查,对比联合筛查与单用血清学或超声筛查的作用疗效。结果:血清学筛查高危孕妇有184例,异常胎儿确诊9例,检出率为56.25%;超声筛查显示高危孕妇64例,异常胎儿确诊6例,检出率为37.50%;联合筛查结果显示,高危孕妇50例,确诊胎儿异常11例,检出率为68.75%。结论:较之单用血清学或超声筛查,联合筛查对孕中期孕妇进行检查,能够明显提高异常胎儿检出率,降低假阳性孕妇诊出率,减少畸形胎儿的出生。     

血清学指标结合彩色多普勒超声对孕早期唐氏综合征筛查的研究

目的:探讨血清学指标结合彩色多普勒超声对孕早期唐氏综合征筛查的临床效果。方法:回顾性分析2019年1月-2020年12月期间来我院就诊的62名11-13+周孕产妇的临床资料,采用时间分辨荧光免疫分析法检测孕妇血清中妊娠相关血浆蛋白A(PAPP-A)以及游离β-人绒毛膜促性腺激素(Fβ-HCG),联合超声测定胎儿颈部透明层厚度(NT)。结果:2例通过引产证实存在唐氏综合征。血清学检查检出率为50.00%,彩色多普勒超声检出率为50.00%,联合检查检出率为100.00%,联合检查显著优于血清学、彩色多普勒超声单独检测(P0.05)。2例确诊为唐氏综合征胎儿的孕妇年龄大于34岁,孕周在12-13周,仅有1例血清学检查高于唐氏综合征高风险截断值为1:250,彩色多普勒超声检查提示NT3mm。唐氏综合征筛查风险高低与妊娠结局相关,高风险组妊娠异常率显著高于低风险组,且数据差异有统计学意义(P0.05)。结论:血清学指标结合彩色多普勒超声对孕早期唐氏综合征筛查的检出率高,对妊娠结局有一定指导意义,值得在临床上推广。     

四维超声在中孕期双胎妊娠中的应用价值

目的:探讨四维超声在中孕期双胎妊娠胎儿产前超声检查的应用价值。方法:选用72例双胎144个胎儿,于孕龄20周-22周进行四维超声检查,分析检查结果。结果:四维超声检查双胎72例,其中双胎之一死亡1例,心脏异常者8例,中枢神经系统异常1例,颜面部异常1例,胎盘附属物异常21例。结论:四维超声在中孕期双胎产前超声检查中有较高的临床应用价值,值得推广。     

超声对胎盘绒毛膜血管瘤的诊断价值分析

目的:应用超声检查胎盘肿瘤,可以早期提示医务人员及孕妇,检测孕妇孕期并发症。方法:总结了2015年四维彩超检查2320例常规产前筛查孕妇,年龄18-46岁,孕周22-28周,使用仪器日历小二郎神,探头频率:3.5MHz。结果:2320例检出胎盘肿瘤10例,其中胎盘囊肿1例,胎盘血管瘤1例,胎盘血窦2例,胎盘血池6例,均经产后娩出胎盘实体病理证实。结论:胎盘是胎儿与母体间进行物质交换的器官,是由羊膜、绒毛膜和基底膜构成,胎盘肿瘤较少见,常见的有:胎盘囊肿、胎盘血管瘤。     

产前B超用于诊断胎儿异常的临床价值

目的:探讨产前b超用于诊断胎儿异常的临床价值。方法:回顾性分析于2018年1月-2018年5月在本院接受产前检查并分娩的100例产妇的产前B超诊断结果。结果:①经B超诊断,有10例胎儿异常,分娩后证实有11例胎儿异常,产前B超诊断的准确性为99.0%(99/100),灵敏度为90.9%(10/11),特异性为100.0%(89/89)。②B超检查确诊100名孕妇中有10例胎儿异常,概率为10%,产后确诊100名孕妇中有11例胎儿异常,概率为11%,差异无统计学意义,P0.05。结论:产前B超检查可以清楚显示胎儿的发育情况,器官结构,有利于分辨异常胎儿,值得推广应用。     

Enhancement of Er I13/2 population in Y2O3 by energy transfer to Ce

We report measurements of the energy transfer between Er³⁺ and Ce³⁺ in Y₂O₃. The transition between the Er^{3+ 4}I_11/2 and ⁴I_13/2 excited states can be stimulated by energy transfer to Ce³⁺, augmenting the population in the ⁴I_13/2 state at the expense of that in the ⁴I_11/2 state. Experiments were performed on Y₂O₃ planar waveguides doped with 0.2 at.% erbium and 0–0.42 at.% cerium by ion implantation. From measurements of Er³⁺ decay rates as a function of cerium concentration we derive an energy transfer rate constant of 1.3×10⁻¹⁸ cm³/s. The efficiency of the energy transfer amounts to 0.47 at 0.42 at.% cerium. The energy transfer rate constant measured in Y₂O₃ is two times smaller for Er³⁺→Ce³⁺ than that for Er³⁺→Eu³⁺ in the same material.     

Yb to Er energy transfer and rate-equations formalism in the eye safe laser material Yb:Er:Ca2Al2SiO7

Rate equations formalism is used to predict the population ratio of the Er^{3+ 4}I_13/2 levels involved in the 1.55 μm laser transition in the Yb:Er:CAS laser materials. An effective Yb → Er energy transfer, favourable to the Er³⁺ 1.55 μm laser emission, is demonstrated in this laser host. Indeed, the Yb → Er transfer and the Er → Yb back transfer rates are calculated to be 6 x 10⁻¹⁶ and 0.45 x 10⁻¹⁶ cm³ s⁻¹, respectively. Attempts of codoping the system with Nd³⁺, Eu³⁺ and Ce³⁺ have been realised in order to increase the population of the Er^{3+ 4}I_13/2 laser emitting level. Best results are obtained with Ce³⁺ ion since in the sample containing 6 x 10²⁰ Ce³⁺/cm³, the Er^{3+ 4}I_11/2 level lifetime is divided by a factor of 3 while the Er^{3+ 4}I_13/2 fluorescence lifetime remains unaffected. On the contrary, codoping with Nd³⁺ or Eu³⁺ ions simultaneously decreases the Er^{3+ 4}I_11/2 and ⁴I_13/2 kinetics parameters. The role of the other parameters such as Yb/Er concentrations ratios is also discussed.     

Effect of radiation trapping on the emission properties of Er: I13/2 → I15/2 transition in oxide glasses

The effect of radiation trapping on the emission properties of Er³⁺-doped tellurite and phosphate glasses has been investigated as the function of sample thickness and doping concentration. It was found that radiation trapping exists generally in two glass matrices, even at low doping concentration (0.1 mol% Er₂O₃). The larger effect of radiation trapping in tellurite glasses compared with phosphate glasses is due to its larger emission cross-section at 1.5 μm band and the spectral overlap between the emission and absorption spectra of Er³⁺: ⁴I_13/2 ↔ ⁴I_15/2transition. Due to radiation trapping, the measured lifetime of the Er³⁺: ⁴I_13/2 level in tellurite glasses increases by about 11–37% with increasing the sample thickness at the different erbium doping concentration, while 6–17% for phosphate glasses. And the full-width at half maximum of fluorescence (FWHM) of Er³⁺: ⁴I_13/2 → ⁴I_15/2 transition in tellurite glasses increased by about 15–64% with increasing the sample thickness, while 11–55% for phosphate glasses. It caused a high overestimation on the figure of merits (FOM) for amplifier bandwidth (σ_e × FWHM).     

Infrared absorption and Zeeman effect in Nd doped YVO4

Low temperature infrared transmission studies of Nd³⁺ doped YVO₄ were performed, under a magnetic field B c, in the 1800–8000 cm⁻¹ range of the ⁴I_9/2→⁴I_11/2, ⁴I_13/2, and ⁴I_15/2 Nd³⁺ crystal-field transitions. Good agreement is obtained between the experimental and calculated g-factors. Frequencies of the satellites in the ⁴I_9/2→⁴F_3/2 transitions of the Nd³⁺ isolated ion confirm the presence of ferromagnetic interactions between pairs of coupled Nd³⁺ ions that lift the Kramers doublet degeneracies of their ground state and excited multiplets.     

Spectroscopy of Er and Er–Yb-doped phosphate glasses

Optical absorption and emission properties of Er and Er–Yb-doped phosphate glasses are investigated both at low and room temperature in the near infrared spectral region between 800 and 2000 nm, and the results are thoroughly discussed in connection with the expected transitions originating from the crystal-field split ⁴I_15/2 and ⁴I_13/2 levels of the Er³⁺ ion. Accurate measurements of the ⁴I_13/2 fluorescence lifetimes and the determination of the stimulated emission cross section for the Er transition at 1.5 μm are also reported. Excited state absorption (ESA) from the metastable ⁴I_13/2 level towards the higher energy levels is measured in the 450–1200 nm spectral region. The ESA absorption peaks are in good agreement with the positions of the higher states of the 4f¹¹ Er³⁺ manifold.     

Two- and three-photon upconversion of LaOBr:Er

In this work, the LaOBr:Er³⁺ (0.1%) powders were prepared by solid state reaction. The structural properties of LaOBr:Er³⁺ were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The results show that LaOBr:Er³⁺ has low phonon energy, which indicate that LaOBr:Er³⁺ may have high luminescent efficiency. Under excitation into ⁴I_11/2 level of Er³⁺ ions by 980 nm laser, the two- and three-photon upconverted luminescence of LaOBr:Er³⁺ were recorded. The most intense emissions were come from the ²H_11/2, ⁴S_3/2 → ⁴I_15/2 transitions. The upconversion mechanisms were studied in detail through laser power dependence, and results show that excited state absorption is responsible for the upconversion. The upconversion properties indicate that LaOBr:Er³⁺ may be used in upconversion phosphors.     

Temperature dependencies of excited states lifetimes and relaxation rates of 3–5 phonon (4–6 μm) transitions in the YAG, LuAG and YLF crystals doped with trivalent holmium, thulium, and erbium

The temperature dependencies of the nanosecond multiphonon relaxation (MR) rates of the ³F₃ state of Tm³⁺ in the YLF crystal and of the ⁵F₅ state of Ho³⁺ ion in the YAG and LuAG crystals and of the microsecond MR rates of the ⁴F_9/2 (²H_9/2) state of Er³⁺ ions in YLF were measured in the wide temperature range using direct laser excitation and selective fluorescence kinetics decay registration. For YLF the observed relations are explained by 4-phonon process in the frame of a single-frequency model with hω_eff=450±30 cm⁻¹ for the ³F₃ state of Tm³⁺ and by 5-phonon process with hω_eff=445 cm⁻¹ for the ⁴F_9/2 (²H_9/2) state of Er³⁺. For YAG and LuAG crystals these dependencies are explained by the 3-phonon process with hω_eff=630 cm⁻¹. The decrease of the relaxation rate with the temperature in the range from 13 to 80 K was observed for the ⁴F_9/2 (²H_9/2) state of Er³⁺ in the YLF crystal. It is explained by the redistribution of excited electronic states population of erbium ions over the higher lying Stark levels with different MR probabilities. A good fit of experimental temperature dependence (including the dropping part of the experimental curve) was obtained for single-frequency model (hω_eff=450 cm⁻¹) with W₀₁=8.0×10⁴ s⁻¹ and W₀₂=4.7×10⁴ s⁻¹ accounting Boltzmann distribution of population over two excited Stark levels of the excited state of erbium ions. Employment of this model improves the fit between the experiment and the theory for the ⁵F₅ state of Ho³⁺ ion in YAG as well. Strong influence of the parameters of the non-linear theory of MR, i.e. the reduced matrix elements U^(k) of electronic transitions and the phonon factor of crystal matrix η on the spontaneous MR rates was observed experimentally. The smaller these parameters the slower the spontaneous MR W₀. This fact can be used for searching new active crystal laser media for the mid-IR generation.     

MOS structures with “chlorine” grown oxide and tungsten-gold metallization

Oxide layers produced by the thermal oxidation of silicon in an oxidising atmosphere containing trichloroethylene show better properties when used in MOS transistors. The dielectric strength is improved, and the surface state density is reduced from about 2.8 × 10¹¹ cm⁻² to 1.0 × 10¹¹ cm⁻² compared with normally oxidised silicon.     

Optical properties of rare earth ion (Nd, Er and Tb)-doped alumina films prepared by the sol–gel method

Rare earth ion (Nd³⁺, Er³⁺ and Tb³⁺)-doped alumina films were prepared by the sol–gel method using aqueous alumina sol. The effects of dopant concentration and treatment temperature on the optical properties, absorption and emission were examined for the doped films. Alumina films prepared by this method gave a high dopant concentration (0–15 mol% per alumina). Significant concentration quenching did not occur in this concentration range. The emissions from ⁵D₃ and ⁵D₄ of Tb³⁺-doped film reflected sensitively a matrix environment around Tb³⁺ ions. Er³⁺- and Nd³⁺-doped alumina films resonantly excited by cw Ti–sapphire laser (800 nm) showed upconversion emission at room temperature. The former gave 548 nm (⁴S_3/2→⁴I_15/2) and 640 nm (⁴F_9/2→⁴I_11/2) signals, and the latter 640 nm (⁴G_7/2→⁴I_11/2), which were dependent on alumina.