文献 | 量子荧光|微型光纤光谱仪-ag贵宾会

we present an improved method for on-line ph monitoring in nl-to- l volumes of complex cell medium using two
different multiple-internal-reflection photonic systems. preliminary absorbance tests of the complex culture medium
showed significant peaks at two different wavelengths (450 and 560 nm) due to the presence of phenol red ph indicator. this observed absorbance may be exploited for non-invasive optical monitoring applications. a full characterization of
the photonic systems using a surrogate culture medium yielded a maximum sensitivity of 0.20 ± 0.00 and lowest lod of 0.04 ± 0.00 ph units in the ph range between 6 and 8 (standard in mammalian cell culture).

frankfurters are the most popular comminuted products in the us and account for the 25% of all sausages sold (nhdsc, 2006). base on an average cooking loss (weight, %) of 2.64 (optimum chopping conditions), the estimated economic loss resulting from non optimum emulsion stability during the cooking process was estimated to range between 0.2 and 1.65 billion dollar per year (only in the us). a number of off-line variables have been defined to characterize meat emulsions (emulsion capacity, mulsion stability, droplet size, etc.). however, no method is currently available to predict the emulsion stability during the chopping process, while corrective actions are still feasible. improving process control and automation of the meat emulsification process will reduce the economical impact of emulsion breakdown in meat industry worldwide. the objective of this study was to determine if light backscatter intensity measured during the chopping process could be used to predict the susceptibility of the emulsion to loose weight during cooking. a completely randomized factorial design with two fat levels (15, 30%), two hydrolyzed potato protein (hpp) levels (0, 2.5%) and three replicates were used in this study to obtain a wide range of lipid oxidation susceptibility. hpp levels were included as a natural source of antioxidant agents. adjusted proportions of pork lean and fat meats, hpp, nacl, water and ice were chopped up to an emulsion temperature of 15°c. the optical properties of the raw emulsions were characterized by visible-nir light backscatter measurements. cielab colour coordinates of raw emulsions were determined using a portable colorimeter. weight loss of cooked emulsions was also measured. the best single-, two-, three- and four-variable models for predicting cooking losses were selected using the sas maximum r2 procedure. the variables taken into consideration in the selection procedure were the colour coordinates and the optical parameters obtained from the light scatter spectral scan. several colour and light scatter parameters showed potential for online prediction of cooking loss.

this paper reports a tunable visual color filter based on a microfluidic transmission grating. the grating lines are formed by the microflows in an array of evenly spaced straight microchannels. in experimental study, the transmission of white light measures a shift of visual color from red to blue in the zeroth order diffraction in response to a change of the refractive index from 1.3290 to 1.3782 in the microflows. the merit of large tunability of transmission peak =408 nm makes this grating potential for various applications in biological and chemical measurements, such as space- and time-resolving micropattern spectrophotometers and separation of the fluorescence from the excitation.

利用波长为1.06 μm、单脉冲能量约为500 mj的脉冲nd:yag激光经焦距为300 mm的正透镜聚焦，使焦点处激光能量密度剧增而引起大气分子中的原子电离，在发生同波长激光散射和多光谱电磁辐射现象的同时，开展空间分辨光谱的探测，获得1.06 μm脉冲激光经大气等离子体散射的空间分布情况。采用hr4000光谱仪对散射情况进行测量分析，通过计算机模拟计算得到等离子体对1.06 μm激光散射的方向图，基于mie理论解释了入射波长为1.06 μm脉冲激光散射角与散射强度之间的关系。