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oe1(光电查) - 科学论文

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出版时间
  • 2017
研究主题
  • spectral reconstruction
  • interference
  • polarization
  • transform
  • imaging spectrometer
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • BITTT
  • Zhejiang University
  • Guilin University of Aerospace Technology
92 条数据
?? 中文（中国） ▾

  • Metabolic imaging with the use of?fluorescence lifetime imaging microscopy (FLIM) accurately detects mitochondrial dysfunction in?mouse oocytes

    摘要： To determine whether metabolic imaging with the use of fluorescence lifetime imaging microscopy (FLIM) identifies metabolic differences between normal oocytes and those with metabolic dysfunction. Experimental study. Academic research laboratories. None. Oocytes from mice with global knockout of Clpp (caseinolytic peptidase P; n ? 52) were compared with wild-type (WT) oocytes (n ? 55) as a model of severe oocyte dysfunction. Oocytes from old mice (1 year old; n ? 29) were compared with oocytes from young mice (12 weeks old; n ? 35) as a model of mild oocyte dysfunction. FLIM was used to measure the naturally occurring nicotinamide adenine dinucleotide dehydrogenase (NADH) and flavin adenine dinucleotide (FAD) autofluorescence in individual oocytes. Eight metabolic parameters were obtained from each measurement (4 per fluorophore): short (t1) and long (t2) fluorescence lifetime, fluorescence intensity (I), and fraction of the molecule engaged with enzyme (F). Reactive oxygen species (ROS) levels and blastocyst development rates were measured to assess illumination safety. In Clpp-knockout oocytes compared with WT, FAD t1 and t2 were longer and I was higher, NADH t2 was longer, and F was lower. In old oocytes compared with young ones, FAD t1 was longer and I was lower, NADH t1 and t2 were shorter, and I and F were lower. FLIM did not affect ROS levels or blastocyst development rates. FLIM parameters exhibit strong differentiation between Clpp-knockout versus WT, and old versus young oocytes. FLIM could potentially be used as a noninvasive tool to assess mitochondrial function in oocytes.

    关键词： Mitochondria,aging,mitochondrial unfolded protein response,fluorescence lifetime imaging microscopy,CLPP,FLIM,oocyte

    更新于2025-09-10 09:29:36

  • [ASME ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - San Francisco, California, USA (Monday 27 August 2018)] ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - Viscoplastic Constitutive Model for High Strain Rate Mechanical Properties of SAC-Q Leadfree Solder After High-Temperature Prolonged Storage

    摘要： Electronics in automotive underhood and downhole drilling applications may be subjected to sustained operation at high temperature in addition to high strain-rate loads. SAC solders used for second level interconnects have been shown to experience degradation in high strain-rate mechanical properties under sustained exposure to high temperatures. Industry search for solutions for resisting the high-temperature degradation of SAC solders has focused on the addition of dopants to the alloy. In this study, a doped SAC solder called SAC-Q solder have been studied. The high strain rate mechanical properties of SAC-Q solder have been studied under elevated temperatures up to 200°C. Samples with thermal aging at 50°C for up to 6-months have been used for measurements in uniaxial tensile tests. Measurements for SAC-Q have been compared to SAC105 and SAC305 for identical test conditions and sample geometry. Data from the SAC-Q measurements has been fit to the Anand Viscoplasticity model. In order to assess the predictive power of the model, the computed Anand parameters have been used to simulate the uniaxial tensile test and the model predictions compared with experimental data. Model predictions show good correlation with experimental measurements. The presented approach extends the Anand Model to include thermal aging effects.

    关键词： SAC-Q solder,thermal aging,high strain rate,mechanical properties,Anand Viscoplasticity model

    更新于2025-09-10 09:29:36

  • [ASME ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - San Francisco, California, USA (Monday 27 August 2018)] ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - Investigation of the Effects of High Temperature Aging on the Mechanical Behavior of Lead Free Solders

    摘要： Lead free solders are renowned as interconnects in electronic packaging due to their relatively high melting point, attractive mechanical properties, thermal cycling reliability, and environment friendly chemical properties. The mechanical behavior of lead free solders is highly dependent on the operating temperature. Previous investigations on mechanical characterization of lead free solders have mainly emphasized stress-strain and creep testing at temperatures up to 125 °C. However, electronic devices, sometimes, experience harsh environment applications including well drilling, geothermal energy, automotive power electronics, and aerospace engines where solders are exposed to very high temperatures from 125-200 °C. Mechanical properties of lead free solders at elevated temperatures are limited. In this work, we have investigated the mechanical behavior SAC305 (96.5Sn-3.0Ag-0.5Cu) and SAC_Q (SAC+Bi) lead free solders at extreme high temperatures up to 200 °C. Stress-strain tests were performed on reflowed uniaxial specimens at four elevated temperatures (T = 125, 150, 175, and 200 °C). In addition, changes of the mechanical behavior of these alloys due to isothermal aging at T = 125 oC have been studied. Extreme care has been taken during specimen preparation so that the fabricated solder uniaxial test specimens accurately reflect the solder material microstructures present in actual lead free solder joints. High temperature tensile properties of the solders including initial modulus, yield stress, and ultimate tensile strength have been compared. As expected, our results show substantial degradations of the mechanical properties of lead-free solders at higher temperatures. With prior aging, these degradations become even more significant. Comparison of the results has shown that the addition of Bi to traditional SAC alloys improves their high temperature properties and significantly reduces their aging induced degradations.

    关键词： Yield Stress,Ultimate Tensile Strength,Stress-Strain Curve,SAC alloy,Modulus,Lead-Free Solder,Aging

    更新于2025-09-09 09:28:46

  • A Reconfiguration Method for Extracting Maximum Power from Non-Uniform Aging Solar Panels

    摘要： Aging affects different photovoltaic (PV) modules in a PV array in a non-uniform way, thereby leading to non-uniform working conditions of the PV modules and resulting in variations in the power outputs of the PV array. In this paper, an algorithm is developed for optimising the electrical con?guration of a PV array during the non-uniform aging processes amongst the PV modules. A new PV array recon?guration method is proposed to maximize the power generation from non-uniformly aged PV arrays through rearrangements of the positions of the PV modules without having to replace the aged PV modules with new ones, thereby saving on maintenance costs. This recon?guration strategy requires information about the electrical parameters of the PV modules in an array, so as to choose the optimal recon?guration topology. In this algorithm, the PV modules are sorted iteratively in a hierarchy pattern to reduce the effect of mismatch due to the non-uniform aging processes amongst PV modules. Computer simulation and analysis have been carried out to evaluate the effectiveness of the proposed method for different sizes of non-uniform aged PV arrays (4 × 4, 10 × 10, and 100 × 10 arrays) with MATLAB. The results show an improvement in the power generation from a non-uniformly aged PV array and can be applied to any size of PV array.

    关键词： non-uniform aging,rearrangement,MPPT,solar PV

    更新于2025-09-09 09:28:46

  • Structure and Stability of C:H:O Plasma Polymer Films Co-Polymerized Using Dimethyl Carbonate

    摘要： C:H:O plasma polymer ?lms (PPFs) were deposited by means of plasma-enhanced chemical vapour deposition using the non-toxic, biodegradable organic compound dimethyl carbonate (DMC) at various plasma powers and pressures in order to control the degradation properties related to the carbonate ester group. Coating properties using pure DMC monomer vapours were compared to co-polymerized ?lms from gaseous mixtures of DMC with either ethylene (C2H4) or carbon dioxide (CO2) affecting deposition rate and chemical composition. C:H:O ?lm properties were found to depend primarily on the amount of oxygen in the plasma. To investigate the PPF stability during aging, changes in the composition and properties were studied during their storage both in air and in distilled water over extended periods up to 5 months. It was shown that aging of the ?lms is mostly due to oxidation of the plasma polymer matrix yielding slow degradation and decomposition. The aging processes and their rate are dependent on the intrinsic amount of oxygen in the as-prepared C:H:O ?lms which in turn depends on the experimental conditions and the working gas mixture. Adjustable ?lm properties were mainly attained using a pure DMC plasma considering both gas phase and surface processes. It is thus possible to prepare C:H:O PPFs with controllable degradability both in air and in water.

    关键词： plasma polymerization,aging,degradability,thin ?lms,chemical composition

    更新于2025-09-09 09:28:46

  • Optical Spectroscopy Methods in the Estimation of the Thermal Stability of Bimetallic Pd–Rh/Al2O3 Three-Way Catalysts

    摘要： A series of three-way catalysts containing palladium and rhodium were prepared by an incipient wetness impregnation of support with aqueous solution of [Pd(NH3)4](NO3)2 and Na3[Rh(NO2)6] compounds. Both pure and La-doped aluminum oxides were used as a support. The catalysts showed very close activity under stoichiometric and reductive conditions, but were different in terms of thermal stability being tested in a prompt thermal aging regime. UV–Vis and luminescence spectroscopies were found to be informative for diagnostics of rhodium and palladium concentration and state, thus giving the possibility to follow the changes taking place with active components (migration, agglomeration, bulk diffusion).

    关键词： Metal migration,Prompt thermal aging,UV–Vis spectroscopy,Three-way catalysts,Luminescence spectroscopy

    更新于2025-09-09 09:28:46

  • Pattern Recognition Analysis of Age-Related Retinal Ganglion Cell Signatures in the Human Eye

    摘要： PURPOSE. To characterize macular ganglion cell layer (GCL) changes with age and provide a framework to assess changes in ocular disease. This study used data clustering to analyze macular GCL patterns from optical coherence tomography (OCT) in a large cohort of subjects without ocular disease. METHODS. Single eyes of 201 patients evaluated at the Centre for Eye Health (Sydney, Australia) were retrospectively enrolled (age range, 20–85); 8 3 8 grid locations obtained from Spectralis OCT macular scans were analyzed with unsupervised classi?cation into statistically separable classes sharing common GCL thickness and change with age. The resulting classes and gridwise data were ?tted with linear and segmented linear regression curves. Additionally, normalized data were analyzed to determine regression as a percentage. Accuracy of each model was examined through comparison of predicted 50-year-old equivalent macular GCL thickness for the entire cohort to a true 50-year-old reference cohort. RESULTS. Pattern recognition clustered GCL thickness across the macula into ?ve to eight spatially concentric classes. F-test demonstrated segmented linear regression to be the most appropriate model for macular GCL change. The pattern recognition–derived and normalized model revealed less difference between the predicted macular GCL thickness and the reference cohort (average 6 SD 0.19 6 0.92 and (cid:2)0.30 6 0.61 lm) than a gridwise model (average 6 SD 0.62 6 1.43 lm). CONCLUSIONS. Pattern recognition successfully identi?ed statistically separable macular areas that undergo a segmented linear reduction with age. This regression model better predicted macular GCL thickness. The various unique spatial patterns revealed by pattern recognition combined with core GCL thickness data provide a framework to analyze GCL loss in ocular disease.

    关键词： pattern recognition,aging,optical coherence tomography,ganglion cells,image analysis (clinical)

    更新于2025-09-09 09:28:46

  • Effects of Age, Race, and Ethnicity on the Optic Nerve and Peripapillary Region Using Spectral-Domain OCT 3D Volume Scans

    摘要： Purpose: To evaluate the effects of age, race, and ethnicity on the optic nerve and peripapillary retina using spectral-domain optical coherence tomography (SD-OCT) three-dimensional (3D) volume scans in normal subjects. Methods: This is a cross-sectional study performed at a single institution in Boston. All patients received retinal nerve fiber layer (RNFL) scans and an optic nerve 3D volume scan. The SD-OCT software calculated peripapillary RNFL thickness, retinal thickness (RT), and retinal volume (RV). Custom-designed software calculated neuroretinal rim minimum distance band (MDB) thickness and area. Results: There were 272 normal subjects, including 175 whites, 40 blacks, 40 Asians, and 17 Hispanics. Rates of age-related decline were 2.3%, 2.0%, 1.7%, 3.3%, and 4.3% per decade for RNFL, RT, RV, MDB neuroretinal rim thickness, and MDB area, respectively. The RNFL was most affected by racial and ethnic variations, with Asians having thicker global, superior, and inferior RNFL, Hispanics having thicker inferior RNFL, and blacks having thinner temporal RNFL, compared to whites. For MDB thickness and area, Asians had smaller nasal values and blacks had smaller temporal values. Peripapillary RT and RV parameters were not influenced by race and ethnicity. Conclusions: All of the parameters exhibited age-related declines. RNFL, MDB thickness, and MDB area demonstrated racial and ethnic variations, while peripapillary RT and RV did not. Translational Relevance: This study demonstrates that both normal aging and ethnicity affect several novel 3D OCT parameters used to diagnose and monitor glaucoma (i.e., RT, RV, and MDB), and this should be factored in when making clinical decisions based on these parameters.

    关键词： aging,age,optic nerve,spectral-domain OCT,race,peripapillary retina,three-dimensional OCT

    更新于2025-09-09 09:28:46

  • Effect of increasing heart rate on finger photoplethysmography fitness index (PPGF) in subjects with implanted cardiac pacemakers

    摘要： Finger photoplethysmography (PPG) is a noninvasive method that measures blood volume changes in the finger. The PPG fitness index (PPGF) has been proposed as an index of vascular risk and vascular aging. The objectives of the study were to determine the effects of heart rate (HR) on the PPGF and to determine whether PPGF is influenced by blood pressure (BP) changes. Twenty subjects (78±8 years, 3 female) with permanent cardiac pacemakers or cardioverter defibrillators were prospectively recruited. HR was changed by pacing, in a random order from 60 to 100 bpm and in 10 bpm increments. At each paced HR, the PPGF was derived from a finger photoplethysmogram. Cardiac output (CO), stroke volume (SV) and total peripheral resistance (TPR) were derived from the finger arterial pressure waveform. Brachial blood pressure (BP) was measured by the oscillometric method. This study found that as HR was increased from 60 to 100 bpm, brachial diastolic BP, brachial mean BP and CO were significantly increased (p<0.01), whilst the PPGF and SV were significantly decreased (p<0.001). The effects of HR on the PPGF were influenced by BP, with a decreasing HR effect on the PPGF that resulted from a higher BP. In conclusion, HR was a significant confounder for PPGF and it must be taken into account in analyses of PPGF, when there are large changes or differences in the HR. The magnitude of this effect was BP dependent.

    关键词： blood pressure,vascular aging,photoplethysmography,heart rate,PPG fitness index

    更新于2025-09-09 09:28:46

  • Photocarcinogenesis & Photoprotection || Ultraviolet Radiation (UVR): An Introduction

    摘要： Radiant energy of sun is essential to perform metabolic processes of all flora and fauna on the earth. The electromagnetic radiations (EMR) emitted by sun extend from very long wavelength radiation, such as radiowaves (A ″′ 3 × 108 m), to very short wavelength radiation, such as cosmic rays (A ″′ 3 × 10?19 m). The EMR reaching at the earth surface contains wavelength from 290 to 4000 nm. However, the UV portion covers from 200 to 400 nm. The range from 200 to 400 nm is often arbitrarily categorized into UVA, UVB, and UVC radiation. Solar radiation less than 290 nm does not reach at the earth’s surface due to the presence of O3 layer in stratospheric zone. But, last from few decades due to anthropogenic activities, the concentration of ozone layer decreases on stratospheric zone. As a consequence of that, UVB radiation levels are rising to 1% a year. Thus, the deleterious health effects on human beings (skin aging, cataracts, skin cancer, and immune suppression) are enhanced by UVR.

    关键词： Skin cancer,Ozone,UVR,Skin aging,EMR

    更新于2025-09-09 09:28:46