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The mechanism of crack occurrence and propagation in optical fibers were reviewed with emphasis on the reliability of optical fibers.The lifetime prediction model of communication optical fibers were given on the basis of the fracture mechanics.The stresses distribution of optical fibers in the configuration of fiber coils was analyzed.A general model was derived for evaluating the mechanical reliability of this kind of coiled sensing fibers.The model was then simplified to an alternative model for engineering applications.This simplified model would bring the conserved results out rapidly and simply.Several numerical calculations of the failure probability in service time of various fiber coils with different fiber radius and bending radius were carried out using the simplified model.The results displayed the dependence of the failure probability on the parameters of the fibers,coils,and the process.According to the relation,the failure probability and the lifetimes could be estimated for fiber coils installed.Meanwhile,the relations provided the guidelines to various design solutions of the fiber coils with deferent geometric configurations and service conditions in the future.

The measurement of blood glucose are enzymatic and biochemical methods which are destructive.Raman technique is used to detect blood glucose and a new data analysis method is established to analyse blood glucose concentration,which is a noninvasive and rapid blood glucose tests.Using mice as experimental models,Raman spectra of blood taken from the tails are acquried half an hour after injection of glucose.Raman spectra are collected every 15 minutes and accompanied by blood glucose meter to get the blood glucose value to be reference.1 125 cm-1 is characteristic peak of glucose and glucose in blood is called blood glucose,so 1 125 cm-1 is chosen as the peak of blood glucose in the Raman spectra of blood.1 549 cm-1 is characteristic peak of hemoglobin which is stable in the body,so 1 549 cm-1is used to be internal standard to research 1 125 cm-1 intensity.The result shows that the change of 1 125 cm-1/1 549 cm-1 may well correspond with changes in blood glucose and they have a good linear relationship.The experiments show that this Raman technique can reflect the changes of blood sugar levels noninvasive.

A novel techique of sorting yeast cell based on Raman characteritics of target products synthesized by microorganisms was developed by using Raman microspectroscopy coupled with optical manipulatation.To sort oleaginous yeast and carotenoid-producing yeast,the plant oil and β-carotene were chosen as the target products and their Raman characteritics,the intensity ratios of 1 440 cm-1 and 1 602 cm-1 band(i.e.I1440/I1602) for oil,and I1157/I1654 or I1520/I1654 for carotenoid,were extracted and marked as target cells.Single yeast cell was captured and manipulated by using a 780 nm laser,and the Raman spectra of trapping cell was acquired simultaneously.A real-time computer distinguishing program was used to assist the sorting.The distinguished cells were then extracted and validated by following culture and Raman detection.This work provides a new method for screening microorganisms synthesize products with economic value.

Raman tweezers is used to probe the oxygen carrying capacity of erythrocytes.The effects of laser power on erythrocytes are compared.An indicator for distinguishing oxygenated and deoxygenated erythrocytes is chosen and utilized to analyze the oxygen carrying capacity of erythrocytes from different storage time and different health state.The result shows that strong power of laser led to the bands at 1 248,1 371 cm-1,the markers of heme aggregation,increasing.The ratio I1 638/I1 547,a well indicator for distinguishing oxygenated state from deoxygenated state,reveals that the oxygen binding capacity of preserved erythrocytes increase as storage time extending,while the deoxidization capacity is not change significantly.Erythrocytes from HbH-CS,an alpha-thalassemia disease,are easier to oxygenate than normal controls,but difficult to deoxygenate.The findings demonstrate Raman tweezers can be a rapid,non-invasive,sensitive technique for analyzing and evaluating the oxygen carrying capacity of erythrocytes.

Real-time monitoring the gelatinization process of single rice starch particle using laser tweezers Raman spectroscopy system under the condition of excessive water and special heating mode is reported.These Raman spectra of gelatinization process are acquired using an imaging CCD spectrograph and the gelatinization process is remarked by the changes of spectra peak height.The experimental result further confirmed the fact that the band of 477cm-1 is assigned as skeletal mode.The rate of gelatinization about single rice starch granules is studied by analyzing the C-O-H group related characteristic peaks which locate at the band of 1 052,1 083,1 127,1 339 cm-1.The results demonstrate that the rate of gelatinization accelerates with rising temperature until the end of gelatinization process.