Solidification process of conventional superalloy by confocal scanning laser microscope

The solidification process of a conventional superalloy, IN718, was investigated by confocal scanning laser microscope （CSLM）. The liquid fraction during solidification was obtained as a function of real time and temperature in reference with the in-situ observation. The characteristics of L→γ transformation were analyzed and the γ growing rate of each stage was also calculated. Scheil equation was employed to predict the segregation behavior, and the predict results are in consistence with the experimental results. As a result, the confocal scanning laser microscope shows a great potential for solidification process research.

In situ observation of the dissolution kinetics of Al_(2)O_(3) particles in CaO–Al_(2)O_(3)–SiO_(2) slags using laser confocal scanning microscopy

The dissolution kinetics of Al_(2)O_(3) in CaO-Al_(2)O_(3) SiOslags was studied using a high-temperature confocal scanning laser microscope at 1773 to 1873 K.The results show that the controlling step during the Al_(2)O_(3) dissolution was the diffusionin molten slag.It was found that the dissolution curves of Al_(2)O_(3) particles were hardly agreed with the traditional boundary layer diffusion model with the increase of the CaO/Al_(2)O_(3) ratio of slag.A modified diffusion equation considering slag viscosity was developed to study the dissolution mechanism of Al_(2)O_(3) in slag.Diffusion coefficients of Al_(2)O_(3) in slag were calculated as 2.8×10to 4.1×10m~2/s at the temperature of 1773-1873 K.The dissolution rate of Al_(2)O_(3) increased with higher temperature,CaO/Al_(2)O_(3),and particle size.A new model was shown to be v_(Al_(2)O_(3))=0.16×r_(0)^(1.58)×x^(3.52)×(T-T_(mp))^(1.11)to predict the dissolution rate and the total dissolution time of Al_(2)O_(3) inclusions with various sizes,where vAl_(2)O_(3) is the dissolution rate of Al_(2)O_(3) in volume,μm^(3)/s;x is the value of CaO/Al_(2)O_(3) mass ratio;R_(0) is the initial radius of Al_(2)O_(3),μm;T is the temperature,K;T_(mp) is the melting point of slag,K.

Confocal Laser Scanning Microscope Evaluation of Early Bacterial Colonization on Zirconium Oxide and Titanium Surfaces:An in vivo Study

To investigate the bacterial colonization on zirconium oxide and titanium surfaces in vivo quantitatively using a confocal laser scanning microscope （CLSM）. Ten samples of zirconium oxide ceramic and commercially pure titanium were fabricated and polished using silicon carbide abrasive paper. One sample from each group was evaluated topographic pattern under a scanning electron microscope. One sample from each group was to evaluate roughness using a profilometer. Eight volunteers were selected. The samples were cemented at the buccal surfaces of upper first molars. All samples were removed after 48 hours, immersed in SYTO-9 and propidium iodide fluorescent to stain for adherent bacteria and obseIved with CLSM. Fewer bacteria were observed in zirconia group than titanium group. However, there was no statistical difference between two groups. The experimental results demonstrate that zirconium oxide may be considered as a promising material for dental implant abutments.

Quantum Dots as Fluorescent Labels for Detection of Heat Shock Protein in Tumor Tissue Using Laser Scanning Confocal Microscope

A new Quantum Dots（Qdots） nanocrystal composed of semiconductor core and zinc sulfide shell, and its feasibility as labels in immunofluorescence analysis for the imaging of tumor biomarkers by laser scanning confocal microscope（LSCM） was investigated. Qdots taged by mercaptoacetic acid were conjugated with second antibody, then imaging differences of Heat Shock Proteins 70（HSP70） in renal carcinoma tissure sections with immunofluorescence analysis method using Qdots bioconjugates and conventional organic dye FITC were observed by LSCM to assess the brightness and opticalstability of Qdots. The experimental results showed Qdots bioconjugates achieved the better results in demonstrating HSP70 with more brighter color and more clear picture than FITC labels. Moreover, the label signals of Qdots did not fade clearly after continued exposure to a 488 nm laser for 1 h. The Qdots bioconjugates have good feasibility in immunofluorescence analysis for the bioimaging by LSCM.

Qualitative analysis of re mineralized carious lesions subjected to fluoride supplement through confocal laser scanning microscope

Aim: 1] Comparative evaluation of the linear depth of induced remineralized lesions after subjecting to fluoride supplements and 2] To assess the average fluorescence at both the demineralized and the remi-neralized zones in all the three study groups under confocal laser scanning microscope. Method: Forty five sound human premolars extracted for orthodon-tic reasons were decoronated 1 mm below the ce-mento-enamel junction and coated with nail varnish except for a 3 × 3 mm window on the buccal surface. The samples were placed in 50 ml of de mineralizing solution at pH 4.6 for 96 hours. Following deminera-lization, the lower half of the 3 × 3 mm window in all the samples were covered with nail varnish to serve as control. The samples were randomly divided into three groups of fifteen teeth each (n = 15) and speci-mens in group A[Nfd] were remineralized using non-fluoridated dentifrice [control], those in groups B [Fd5] and group C [Fd10] using 500 ppm and 1000 ppm of fluoride containing dentifrice, respectively. The specimens were subjected to a 20 day reminera-lization treatment regimen and were sectioned into 100 μm thick sections and two images were captured on the buccal surface from either side of the midpoint of occluso-cervical length using confocal laser scan-ning microscope [CLSM]. Results: were tabulated and statistically analyzed by Anova. Study concluded that 1000 ppm fluoridated dentifrice showed a greater degree of remineralization than other groups and confocal laser scanning microscopes gives promising results in the diagnosis of early enamel lesions over the conventional methods.

Experimental Study on Meiotic Spindles and Chromosomes of Mouse Mature (MⅡ) Stage Oocytes under Laser Scanning Confocal Microscopy

Taking the mouse as a model, the experimental method of observing the morphology of meiotic spindles and chromosomes in mature oocytes were investigated in order to evaluate the effects of various interventions on the quality of oocytes accurately and rapidly. Laser scanning confocal microscope （LSCM） was used to examine the meiotic spindles and chromosomes by the technologies of optical section and three-dimensional （3D） image reconstruction. The results showed that the configurations of meiotic spindles and chromosomes could be observed clearly by LSCM. The normal rate of meiotic spindles and chromosomes was 82% and 86% respectively. It was concluded that the LSCM was a valid instrument to observe the meiotic spindles and chromosomes of mature oocytes and could be used as a valid method to evaluate the quality of MⅡocytes.

高能激光光束质量β因子测量方法

高能激光光束质量β因子测量装置主要用于强激光系统状态调试和综合性能参数诊断,用于评价激光系统出光性能以及远场光斑可聚焦的能力。针对接近衍射极限光束质量β因子测量过程中被测光斑在面阵相机上所占的像素点太少等缺陷,研究了采用聚焦显微放大与高精度扫描狭缝相结合的光束质量β因子测量方法,并对相关方案进行了分析计算。此外还设计了采用固定像差元件及平行光管光源组合的激光光束质量β因子测量结果验证方案,对研制的高能激光光束质量β因子测量装置进行了不确定度分析,测量不确定度优于10%。

枯草芽孢杆菌无细胞上清液抑制单增李斯特菌生物被膜形成的研究

单增李斯特菌(Listeria monocytogenes)是一种常见的食源性致病菌,其生物被膜是导致食品污染和疾病传播的重要原因。该研究选用枯草芽孢杆菌(Bacillus subtilis)无细胞上清液(cell free supernatant,CFS)作为抑制剂,探究B.subtilis CFS在抑制L.monocytogenes野生菌株118(以下简称No.118)生物被膜方面的作用和潜力。首先测定了B.subtilis CFS的最小抑菌浓度(minimum inhibitory concentration,MIC),接着采用结晶紫染色法测定了不同亚最小抑菌浓度下B.subtilis CFS对No.118的生物被膜抑制率,发现不同亚抑菌浓度下的CFS对No.118生物被膜均具有显著的抑制作用,且在1/64 MIC时生物被膜抑制率仍可达到47%;同时B.subtilis CFS对No.118生物被膜代谢活性、自聚集率、表面疏水性、群集泳动能力和膜外聚合物分泌也均有显著抑制作用;最后,通过激光共聚焦显微镜观察了在CFS作用下,No.118生物被膜结构和细胞分布的变化规律,经CFS处理后,No.118生物被膜结构松散,细菌数量明显减少。综上,B.subtilis CFS可通过影响No.118生物被膜细胞的代谢活性、自聚集能力和群集泳动能力以及膜外聚合物的分泌来抑制其生物被膜形成,对探究益生菌代谢产物作为生物被膜抑制剂方面的应用具有重要的参考价值。

300MHZ scanning laser acoustic microscope

The knife-edge and harmonic technique in the Scanning Laser Acoustic Microscope is studied in this paper. The operating frequency of the SLAM can be increased from 100MHz to 300MHz by using the harmonic technique. The acoustic images of some samples are obtained on our SLAM at 300MHz.

Using laser confocal scanning microscope to study ischemia-hypoxia injury in rat brain slice

The level of lipid peroxidation and cellular necrosis in rat living brain slices during brain ischemia-hypoxia injury have been observed using a laser confocal scanning microscope (LCSM) with double labeling of fluorescent probes D-399 (2, 7-dichlorofluorescin diacetate) and propidium iodide (Pl). The hypoxia and/or reoxygenation injury in rat brain slices is markedly decreased by pretreatment with L-NG-nitro-arginine (L-NNA) and N-acetylcysteine (NAC), showing that the nitric oxide (NO) and other free radicals play an important role in brain ischemia-hypoxia injury.

Er∶YAG激光根尖切除断面形貌对牙周膜细胞生长的影响

目的:观察Er∶YAG激光根尖切除断面的形态对牙周膜细胞生长的影响。方法:将66颗离体单根前磨牙随机分为3组(n=22),在距离根尖3 mm处垂直于牙长轴切除根尖形成断面样本,A组使用高速涡轮金刚砂车针,B组使用超声骨刀,C组使用Er∶YAG激光。SEM观察牙根断面残屑、玷污层、牙本质小管、裂隙等情况并测算粗糙度后,将牙周膜细胞接种于各组根片表面进行培养,分别于24、48、72 h时用CCK-8法检测样本表面细胞增殖情况。结果:A组操作时间显著短于B组和C组(P<0.01)。SEM观察显示,C组牙根断面几乎没有残屑、玷污层,可见牙本质小管,A组、B组可见碎屑及玷污层,A组未观察到牙本质小管。3组牙根断面均可见到裂隙,C组的裂隙数目较少。C组牙根断面粗糙度均值为(1487.13±295.90)nm,显著高于A组和B组(P<0.001)。CCK-8法显示,细胞接种于根面24、48、72 h后,各组的细胞数量(A值)均随培养时间的增加而增加,其中C组细胞增殖最明显,48 h和72 h时C组显著高于其他两组(P<0.05)。结论:Er∶YAG激光根尖切除断面形态比超声骨刀和高速涡轮金刚砂车针根尖切除更利于牙周膜细胞在其表面生长。

扫描电镜原位激光加热与高温成像研究

扫描电子显微镜(SEM)原位研究材料高温组织与力学性能是近年来材料领域关注的一个重要方向,在扫描电子显微镜内进行原位加热实验可以直接揭示材料微观组织、力学性能与温度之间的关系。然而传统的电流加热方式在样品温度超过800℃时金属材料会释放出大量热电子,无法获得高质量图像。本研究开发了一种与SEM联用的激光加热台,该加热台使用激光作为加热源,可以对材料进行快速加热以及高分辨原位结构表征。本文详细介绍了激光加热台的设计原理并对加热台温度场进行有限元仿真模拟及分析,以镍基单晶高温合金为例,实现了1370℃原位高温成像,验证了该装置的主要功能。

核桃壳/酚醛树脂生物质复合材料选择性激光烧结工艺参数研究

黑龙江省作为农林业大省,盛产核桃,这种果壳来源丰富且产量高,同时也伴随着大量农业废弃物的产生。为改善这一现状,需要对废弃核桃壳进行合理资源利用。选取废弃核桃壳作为粉末基体材料,将碳含量丰富的酚醛树脂粉作为黏结剂,制备用于选择性激光烧结的核桃壳/酚醛树脂生物质复合材料,不仅可以扩大生物质复合材料粉体的种类,还可以通过该技术的三维性,定制复杂结构的多孔碳前驱体,在海水淡化、新能源方面作出贡献。建立四因素三水平的正交试验方案,通过方差分析法和综合加权评价法,探讨激光功率、扫描速度、扫描间距和分层厚度4因素对烧结件密度、弯曲强度和Z轴精度的影响规律,确定最优激光烧结工艺参数组合,使用扫描电镜(scanning electron microscope,SEM)对成型件烧结断面进行表征。试验结果表明,激光功率对烧结件密度、弯曲强度和Z轴精度的影响最大,扫描速度对烧结件密度和弯曲强度的影响最小,扫描间距对Z轴精度影响最小;最优工艺参数组合为激光功率10 W、扫描速度2 m/s、扫描间距0.1 mm、分层厚度0.12 mm。

激光共聚焦显微镜应用于本科生的实验教学设计

激光共聚焦显微镜等大型仪器的实验教学是实现“新工科”建设的重要推动力,然而目前针对本科生的大型仪器教学却未得到有效普及。通过选取适合于本科生实践操作的微生物荧光染色观察实验以及基于“雨课堂”进行线上线下教学,发挥激光共聚焦显微镜可视化强的特点,激发本科生的求知欲望和探索热情,增强学生的主观能动性,促进以教师为主导向以学生为中心的教学模式转变。实践教学表明,易于操作、可视化强的实验方案有助于学生理解和掌握激光共聚焦显微镜相关的基础知识和未来应用,拓宽学生的知识面和科研视野,提高本科生的实践创新能力。

尼康共聚焦显微镜使用的大数据分析

激光共聚焦显微镜是目前最精密的光学成像仪器,是生命领域重要的研究工具。兰州大学生命科学研究实验中心的尼康共聚焦显微镜两年多时间工作了1万多小时,获取了大量的观测数据。对使用记录的分析表明,仪器在每天上午9点到晚上22点处于饱和工作状态,只有在寒假期间有所降低,说明了全天候开放使用的必要性。观测结果分析得到了很多有价值的信息,例如,488 nm和561 nm激光器使用率都超过了三分之一,单激光和双激光观测占比分别是72%和24%,高灵敏检测通道使用率接近90%等。综合这些信息,可以为共聚焦显微镜的管理和培训提供科学的依据。

激光共聚焦显微镜荧光漂白后恢复实验的制样优化

利用激光共聚焦显微镜进行荧光漂白后恢复(FRAP)实验为研究分子的流动性提供了新的手段。然而,在拟南芥根毛细胞中进行荧光漂白后恢复实验时,由于拍摄时长的影响经常会导致样品脱离原来的焦平面,从而无法获得可靠的数据。以拟南芥根尖为材料,通过实验比较激光共聚焦显微镜下的常规制片、指甲油封片以及甘油制片,结果表明,利用指甲油封片能更好地解决样品离焦问题,可以获取有效的实验数据。

CLMS观察iRoot BP Plus对根尖倒充填封闭效果的体外研究

目的:观察iRoot BP Plus作为根尖倒充填材料封闭根尖的效果。方法:选取上下颌单直根管离体牙60颗,Reciproc blue机用单支镍钛锉预备根管,热牙胶连续波技术充填根管,超声工作尖对离体牙根尖区行倒预备。将离体牙随机分为三组,分别以iRoot BP Plus、MTA、3MZ350树脂行倒充填。体式激光共聚焦扫描显微镜观察倒充填后材料及牙体组织的颜色变化率。上述标本再次随机分为两个亚组,分别浸泡于2%亚甲基蓝溶液和1 g/L罗丹明B荧光染料中,48 h后分别在光学显微镜、扫描电镜和激光共聚焦显微镜下测量染料线性渗漏长度;测量材料与牙本质间的微间隙宽度,观察不同倒充填材料与根管壁间的微观结合形态;计算分析根尖区微渗漏荧光染色面积。通过定性和定量的方法研究不同倒充填材料对根尖封闭性能的影响。结果:iRoot BP Plus组倒充填后未发生明显颜色改变,美观性优于MTA组(P<0.05),但与树脂组比较差异无统计学意义(P>0.05)。iRoot BP Plus组染料渗漏长度较MTA组短(P<0.05),和MTA组染料渗漏长度比较差异无统计学意义(P>0.05)。三组微间隙宽度比较,iRoot BP Plus组<MTA组<树脂组(P<0.05)。三组微渗漏荧光染色面积比较,iRoot BP Plus组<MTA组<树脂组(P<0.05)。结论:iRoot BP Plus具有良好的根尖封闭性、密合性和美观性。

Cr含量对1000 MPa级高强钢熔敷金属组织演变的作用机制

设计开发了5种不同Cr含量的1000 MPa级高强钢埋弧焊材,采用丝极埋弧焊制备了Cr含量为0%~0.9%的熔敷金属,利用OM、SEM、TEM和CLSM等微观组织表征方法研究Cr含量对1000 MPa级高强钢熔敷金属组织演变的影响,并通过拉伸和冲击试验评估其力学性能.结果表明,1000 MPa级高强钢熔敷金属随着Cr含量提高,铁素体转变起始温度由723.3℃提高到740.2℃,贝氏体转变起始温度由470.2℃降低到458.5℃,铁素体转变温度区间扩大,高Cr熔敷金属中贝氏体转变速率较快,熔敷金属中针状铁素体和贝氏体铁素体增加,M-A组元由弥散分布逐渐呈链条状偏聚,先共析铁素体与残余奥氏体减少.熔敷金属冲击断裂形式由低Cr的韧性断裂向高Cr的准解理断裂转变,熔敷金属拉伸强度不断提高,相比于无Cr的熔敷金属,0.9%Cr的熔敷金属抗拉强度和屈服强度分别提高12.4%和17.0%,熔敷金属冲击吸收能量先提高后降低,在−40℃条件下,0.6%Cr的熔敷金属的低温韧性最高为84 J,熔敷金属Cr含量为0.6%时强韧性匹配效果最佳.

铒激光拆除三种全瓷高嵌体的实验研究

目的:本实验采用铒(Er:YAG)激光对不同材质、不同厚度的全瓷高嵌体进行体外照射脱粘,通过模拟临床全瓷高嵌体粘接后的去粘接过程,分析铒激光对于高嵌体、牙体组织微观结构的影响,为临床铒激光拆除全瓷高嵌体提供参考。方法:采用新鲜拔除正畸前磨牙,牙体预备后制作3种不同材质(氧化锆、二硅酸锂玻璃陶瓷、树脂基陶瓷),不同厚度(1 mm,1.5 mm,2 mm)的高嵌体进行粘接,保存一周后使用Er:YAG激光(3 W,4 W)照射全瓷高嵌体同时记录时间。使用扫描电镜观察脱粘后牙体与高嵌体表面的微观形态。结果:3 W功率脱粘接时间:1 mm氧化锆组(196±16)s>1 mm二硅酸锂玻璃陶瓷组(184±20)(s P<0.05);1.5 mm氧化锆组(347±15)s>1.5 mm二硅酸锂玻璃陶瓷组(270±14)(s P<0.05);4 W功率下两种厚度(1 mm,1.5 mm)的高嵌体脱粘时间均有所减少;2 mm厚度的高嵌体在3 W\4 W功率照射下均无法脱粘且出现裂纹;所有树脂基陶瓷高嵌体经长时间不同功率(>20 min,3 W\4 W)照射后均无法取下且出现表面缺陷。结论:材质、功率相同时,瓷块厚度越厚,拆除所需时间越长,所需功率越高;材质、厚度相同时,Er:YAG激光功率越大,脱粘时间越短;厚度、功率相同时,激光照射穿透瓷块可能对瓷块本身产生影响。Er:YAG激光在本实验功率下无法拆除树脂基陶瓷高嵌体。

激光共聚焦显微镜样本制备在研究生实验教学中的应用

激光共聚焦显微镜是一种多功能、高分辨率、高效率的光学设备,在植物细胞结构中通过荧光探针标记相关基因,获得清晰的亚细胞定位信息,如细胞膜、细胞器等结构。以烟草为实验材料,在研究生实验教学中利用LSCM880激光扫描共聚焦显微镜观察烟草下表皮细胞,通过优化样本制作,最终获取清晰的图片。通过实验教学,学生掌握激光共聚焦显微镜的原理、样品制备及操作步骤,提高理论知识与实践操作相结合的能力,加强其对激光共聚焦显微镜的掌握及运用。