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In vivo and in vitro studies reveal that Ursolic Acid (UA) is able to counteract endogenous and exogenous inflammatory stimuli and has favorable anti-inflammatory effects. The antiinflammatory mechanisms mainly include decreasing the release of histamine in mast cells, suppressing the activities of lipoxygenase, cyclooxygenase and phospholipase, and reducing the production of nitric oxide and reactive oxygen species, blocking the activation of the signal pathway, downregulating the expression of inflammatory factors, and inhibiting the activities of elastase and complement. These mechanisms can open up new avenues for the scientific community to develop or improve novel therapeutic approaches to tackle inflammatory diseases, such as arthritis, atherosclerosis, neuroinflammation, liver diseases, kidney diseases, diabetes, dermatitis, bowel diseases, cancer. The anti-inflammatory activity, the anti-inflammatory mechanism of ursolic acid and its therapeutic applications are reviewed in this paper.

Oleanolic acid can inhibit edema and exhibit obvious inhibitory activity to inflammatory by activating of the pituitary-adrenal cortical system, inhibiting the synthesis or release of PGs, inhibiting endotoxin-mediated release of HMGB1 by endothelial cells or regulating MAPK, PI3K/Akt/NF- κB/ICAM-1/JAK/STAT signaling pathways, etc. In recent years, an increased number of interesting research work has been carried out on the anti-inflammatory activity and mechanisms of OA derivatives, such as acyloxyimino derivative, 3-acetylated derivatives, novel 3,5-disubstituted isoxazoles derivatives, acetate, ester derivatives and oximes derivatives. The review summaries and highlights the updated advances on the anti-inflammatory activity and mechanism of OA and its derivatives.

Ginseng is a traditional medicine with a complex chemical composition, wide bioactivity and unique pharmacological action. Many studies have confirmed that ginsenosides are the active ingredients of ginseng, and ginsenosides have always been the focus of different researchers. With the development of modern separation and analysis technology, more than 150 kinds of ginsenosides have been isolated. The ginsenosides Rb1, Rb2, Rc, Rg1 and Re account for more than 80% of total ginsenosides, and other saponins, such as Rd, Rg3 and Rh2, which are minor constituents, accounting for only a small portion of the total amount. In recent years, ginsenosides have been found to possess strong pharmacological activities, such as antioxidation, clearing of oxygen free radicals, reducing calcium overload and anti-apoptosis. Ginsenosides play a protective role in ischemia-reperfusion injury. This paper reviews the protective effects of ginsenosides on myocardial ischemia and ischemiareperfusion injury.

Thirty-two novel DG F-spiroacetal ring-opening derivatives, including 24 acetylated derivatives and 8 nitrogenous derivatives, were designed and synthesized from diosgenin (DG). The cytotoxicity of the novel derivatives was evaluated by MTT assay, except for compounds 4a, 4e, 4i, 4 l, 5a and 5 h, which were potentially cytotoxic to RAW264.7 cells, all the other derivatives had no significant cytotoxicity. The NO release inhibitory activities of novel derivatives were screened by Griess method. The results showed that the anti-inflammatory activity of the DG acetylated derivatives was stronger than the nitrogenous derivatives, and 4a-4 m containing acetyl groups at the 3-position may have better anti-inflammatory effects than 5a-5 k containing free hydroxyl groups. In ELISA assay, compound 4 m exhibited potent anti-inflammatory activity by inhibiting the production of NO in RAW264.7 cells activated by LPS with IC

Neuroinflammation is an intricate process that is associated with both normal and pathological conditions. Microglia-mediated neuroinflammation is known to lead to various neurodegenerative and neurological disorders. A series of 3,4-dihydronaphthalen-1(2H)-one derivatives (1-15) and novel 5,6-dihydrobenzo[h]quinazolin-2-amine derivatives (16-30) were synthesized and characterized by various analytical methods, such as NMR and HRMS. All compounds were evaluated for toxicity, screened for their anti-neuroinflammatory properties, and investigated for the potential molecular mechanism of lipopolysaccharide (LPS) induction in BV2 microglia. Structure activity relationship analysis showed that compound 17 substituted by the 7-fluorine atom on the A-ring and the 3-methoxy on the D-ring had more potential anti-neuroinflammatory activity by inhibiting the secretion of cytokines TNF-α and IL-6. The results of western blotting assay showed that 17 significantly blocked the activation and phosphorylation of IκBα, significantly reduce the expression of NLRP3 inflammatory vesicle-associated proteins, and thus inhibit the activation of NF-κB pathway. Thus, compound 17 was demonstrated to be an excellent potential therapeutic agent for the treatment of neuroinflammation-related diseases.

C34H56O6⋅0.25(C4H8O2), orthorhombic, P212121 (no. 19), a = 8.17152(14) Å, b = 17.6728(3) Å, c = 23.1916(5) Å, V = 3349.18(11) Å3, Z = 4, R gt(F) = 0.0416, wR ref (F 2) = 0.1143, T = 293 K.

C18H17NO3, triclinic, P 1 ‾ $P‾{1}$ (no. 2), a = 7.3950(5) Å, b = 8.6697(5) Å, c = 11.6813(9) Å, α = 85.457(6)°, β = 76.712(6)°, γ = 82.759(5)°, V = 722.07(9) Å3, Z = 2, R gt (F) = 0.0502, wR ref (F 2) = 0.1342, T = 99.9(3) K.

C 20 H 14 F 6 O 2 ${\text{C}}_{20}{\text{H}}_{14}{\text{F}}_{6}{\text{O}}_{2}$ , monoclinic, P21/c (no. 14), a = 14.791(2) Å, b = 8.5303(9) Å, c = 15.531(3) Å, β = 115.474(19)°, V = 1769.1(5) Å3, Z = 4, R g t ${R}_{gt}$ (F) = 0.0574, w R ref $w\,{R}_{\text{ref}}$ (F 2) = 0.1451, T = 100 K. CCDC no.: 2016723

C31H48O5, monoclinic, P21 (no. 4), a = 11.0421(3) Å, b = 6.49710(16) Å, c = 20.4687(4) Å, β = 97.922(2)°, V = 1454.45(6) Å3, Z = 2, R gt(F) = 0.0382, wR ref(F 2) = 0.1024, T = 293(2) K.

C30H52O3, orthorhombic, P212121 (no. 19), a = 6.71147(14) Å, b = 16.6565(4) Å, c = 25.0815(6) Å, V = 2803.85(11) Å3, Z = 4, R gt (F) = 0.0405, wR ref (F 2) = 0.1092, T = 293(2) K.

A static-mode synthetic aperture imaging ladar (SAIL) in which the target and carrying platform are kept still during the collection process is proposed and demonstrated. A target point of 0.5 mm \times 0.5 mm and a two-dimensional (2D) object are reconstructed in the experiments, in which an optical collimator with a focal length of 10 m is used to simulate the far-field condition. The achieved imaging resolution is in agreement with the theoretical design. The static-mode down-looking SAIL has the capability to eliminate the influence from the atmospheric turbulence and can be conveniently operated outdoors.

3D coherent imaging ladar based on frequency modulated continuous wave (FMCW) technology is proposed. The triangle wave is used to modulate chirped laser. The distance information is detected by optical heterodyne technique. Meanwhile, the beam scanning is realized by rotation double-prism. And the 3D target image is obtained. The 3D coherent imaging ladar has advantages of anti-background interference, high sensitivity and long-detected distance. Under the condition of the strongly sunlight background, the targets outdoor are scanned and high resolution images are achieved. This technique has a great potential for applications in extensive imaging ladar fields.

We design two novel d10 metal complexes [Zn(3-qlc)2]n (Zn1), [Cd(3-qlc)2]n (Cd1) (3-Hqlc = quinoline-3-carboxylic acid), which display similar 2D layer structures, and further form 3D 6-connected primitive cubic (pcu) network topology via π⋯π stacking interactions with the point symbol {412·63}. Complexes Zn1 and Cd1 exhibit tunable luminescence and photovoltaic properties as a new type of multifunctional materials. Zn1 and Cd1 show tunable luminescence from blue to green by varying the temperature in the solid state. What's more, both of them exhibit excellent aggregation-induced emission (AIE) properties in DMSO/water mixtures. Encouraged by the UV-visible absorption in an ethanol solution result, Zn1 and Cd1 can be considered as co-sensitizers in combination with N719 to investigate their effect on enhancing the dye-sensitized solar cells (DSSCs) performance. Zn1 and Cd1 could overcome the deficiency in the ruthenium complex N719 absorption in the ultraviolet and blue-violet region, offsetting competitive visible light absorption of I3− and reducing the charge recombination of injected electrons. After being co-sensitized with Zn1 and Cd1, the devices co-sensitized by Zn1/N719 and Cd1/N719 yield an overall efficiency of 7.75% and 7.70%, which are 44.59% and 43.66% higher than that of the device sensitized only by N719 (5.36%).

Down-looking synthetic aperture imaging ladar have bidirectional (positive and negative direction) modulation in the orthogonal direction of travel during phase modulation. The return signal can be also collected in the two directions. The imaging processing with bidirectional modulation is used and demonstrated. The signal-to-noise ratio can be enhanced in this mode synthetic aperture imaging ladar. Meanwhile, the velocity of carrying-platform can be faster. In the experiment, the return signals with bidirectional modulation are stacked and rebuilt. Compared to the unidirectional modulation imaging, the faster and clearer imaging is realized with bidirectional modulation. This technique has a great potential for applications in extensive synthetic aperture imaging ladar fields.

Active polarization imaging technology has recently become the hot research field all over the world, which has great potential application value in the military and civil area. By introducing active light source, the Mueller matrix of the target can be calculated according to the incident light and the emitted or reflected light. Compared with conventional direct detection technology, optical heterodyne detection technology have higher receiving sensitivities, which can obtain the whole amplitude, frequency and phase information of the signal light. In this paper, an active polarization imaging system will be designed. Based on optical heterodyne balanced receiver, the system can acquire the horizontal and vertical polarization of reflected optical field simultaneously, which contain the polarization characteristic of the target. Besides, signal to noise ratio and imaging distance can be greatly improved.

We present a down-looking synthetic aperture imaging ladar demonstrator and its experiments over 1.2 km in the field. The achieved imaging resolution is in agreement with the theoretical design, and the resulting two-dimensional image is satisfied. The capability to eliminate the influence from atmospheric turbulence is fully proven by the experiments.

The complexity and depth of drilling are increasing constantly, so an advanced well control technology is required, and early kick detection as the key to well control is very important. Rapid and accurate kick detection helps to eliminate kick and rebalance the wellbore pressure, which not only improves drilling operation efficiency, but also reduces the probability of blowout, well collapse and other accidents. Accordingly, this paper has analyzed the applicable conditions, advantages and shortcomings, and field applications of the existing kick detection technology including mud pit surface detection, delta flow method, liquid level monitoring in the wellbore detection, gas invasion detection, kick detection while drilling, multi-parameter comprehensive detection system and comprehensive logging detection and analysis technology, and proposed the research trends and application suggestions of kick detection technology.

In order to solve the nonlinear contact problem with the friction action in the mirror assembly, the modeling analysis is carried out by the MPC method of shell-to-solid coupling. Considering the friction factor existing in the contact region, the deformation and stress of the strap obviously changes from fixed region, transition region to contact region, which further produces a serious edge effect around the mirror and leads to the uneven stress distribution. The results show the maximal deformation of the assembly is 9.98 μm and the maximal stress is 10.5 MPa, which has much tolerance to the precision requirement of structure and the admissible stress of material; the influence of heat effect on the surface deformations of mirror is proved to be far greater than that of only gravity load. The advantages of the contact model built by the MPC method are more close to the actual working conditions and more accurate analysis results can be obtained.

A laser collimator is necessary for testing and verification of the pointing, acquisition and tracking (PAT) performance of inter-satellite laser communication terminals on the ground. The laser collimator must have a large clear aperture to fit the PAT performance testing system. The PAT subsystem has a large field of view for the acquisition and a high angular accuracy for the fine tracking. To resolve the conflict between large field of view and fine angular resolution, a large-aperture double-focus laser collimator is proposed and its optical design and mechanical structure are described. The collimator mainly consists of a primary lens, a reflector, a beam-splitting plate, a secondary lens, two compensating lenses, two imaging sensors and a laser. The primary lens directly forms the long focal length arm of the collimator. The combination of the primary lens and the secondary lens form the short focal length arm of the collimator. The collimator has an angular resolution

The Jamin shearing interferometer is very useful in wavefront testing, especially for the low coherent light. Based on this interferometer, a polarization phase-shifting Jamin shearing interferometer is proposed to improve the performance. In the interferometer, two interference beams are linearly polarized and a polarization phase shifter is applied to realize the phase shifting. Different types of configurations of the interferometer are given. With phase-shifting interferograms, the precision of the interferometer can be improved. The interferometer is kept as an equal optical path system and its shearing amount remains changeable with simple structure and easy operation. In experiments, phase-shifting interferograms are obtained by rotating the analyzer. The usefulness of the interferometer is verified.

The near-infrared nonvolatile holographic recording has been realized in a doubly doped LiNbO3:Fe:Rh crystal by the traditional two-center holographic recording scheme, for the first time. The recording performance of this crystal has been investigated by recording with 633 nm red light, 752 nm red light and 799 nm near-infrared light and sensitizing with 405 nm purple light. The experimental results show that, co-doped with Fe and Rh, the near-infrared absorption and the photovoltaic coefficient of shallow trap Fe are enhanced in this LiNbO3:Fe:Rh crystal, compared with other doubly doped LiNbO3 crystals Such as LiNbO3:Fe:Mn. It is also found that the sensitizing light intensity affects the near-infrared recording sensitivity in a different way than two-center holographic recording with shorter wavelength, and the origin of experimental results is analyzed. (C) 2007 Elsevier GrnbH. All rights reserved.

An FFT-based two-step phase-shifting (TPS) algorithm is described in detail and implemented by use of experimental interferograms. This algorithm has been proposed to solve the TPS problem with random phase shift except pi. By comparison with the visibility-function-based TPS algorithm, it proves that the FFT-based algorithm has obvious advantages in phase extracting. Meanwhile, we present a pi-phase-shift supplement to the TPS algorithm, which combines the two interferograms and demodulates the phase map by locating the extrema of the combined fringes after removing the respective backgrounds. So combining this method and FFT-based one, one could really implement the TPS with random phase shift. Whereafter, we systematically compare the TPS with single-interferogram analysis algorithm and conventional three-step phase-shifting one. The results demonstrate that the FFT-based TPS algorithm has a satisfactory accuracy. At last, based on the polarizing interferometry, a schematic setup of two-channel TPS interferometer with random phase shift is suggested to implement the simultaneous collection of interferograms. (c) 2007 Elsevier GrnbH. All rights reserved.

The Mask Cut unwrapping algorithm, a cross between Goldstein's Branch Cut and quality-guided path following algorithm, is generally successful at unwrapping phase; but if no good quality map, wrong placement of branch cuts or bad phase-unwrapping path, it will fail to confine the errors to the low-quality regions and lead to the failure of phase unwrapping. To overcome these drawbacks, we propose a new reliability function (i.e. quality map) based on the fringe modulation (the visibility of the fringes) and second-order phase difference, and improve the reliability-guided phase-unwrapping algorithm. Considering the residues, we use the reliability information to guide the placement of branch cuts and to optimize the phase-unwrapping path. The simulated and experimental data both demonstrate the validity of the new reliability-guided phase-unwrapping method.

We obtain analytical solutions of the coupled wave equations that describe the Bragg diffraction of ultrashort pulsed finite beams by a thick planar grating, using two-dimensional coupled wave theory. The diffraction properties for the case of an ultrashort pulsed finite beam with Gaussian profiles in both the time and spatial domains are investigated. The spectral bandwidth of the diffracted beam, the Bragg selectivity bandwidth and the diffraction efficiency of the volume grating are influenced by the geometry parameter and the input bandwidth. Therefore extra attention should be paid to designing optical elements based on volume gratings for use with ultrashort pulsed waves in applications of pulse shaping and processing.

A fast and reliable phase unwrapping (PhU) algorithm, based on the local quality-guided fitting plane, is presented. Its framework depends on the basic plane-approximated assumption for phase values of local pixels and on the phase derivative variance (PDV) quality map. Compared with other existing popular unwrapping algorithms, the proposed algorithm demonstrated improved robustness and immunity to strong noise and high phase variations, given that the plane assumption for local phase is reasonably satisfied. Its effectiveness is demonstrated by computer-simulated and experimental results.

A simple method for measuring the radius of curvature of laser beams is introduced. It has been developed to estimate the astigmatic aberration of a diode laser. Compared with the interferometry, this method is convenient and straightforward.

In modern distributed measure and control systems, transmission and processing of real-time data requires each communication node to work in a unified time base in order to ensure the timeliness of data transmission. IEEE1588 precision clock synchronization protocol (PTP) is aimed to solve the high-precision clock synchronization, which supports software or hardware implementation. This paper analyzes the factors that affect the accuracy of clock synchronization. Considering the special requirements of the protocol implemented in embedded systems, we propose an adaptive exponential smoothing algorithm to achieve high-precision clock synchronization. Experiments show that this algorithm can significantly improve the accuracy of clock synchronization.

We present a novel phase-shifting vectorial-shearing interferometer with a wedge plate phase-shifter. The interferometer is based on a modified Mach-Zehnder configuration; the common-path nature makes it capable of testing the wavefront of a short coherence-length light source, such as a laser diode. Vectorial shear (shearing in the x and y directions simultaneously) in an arbitrary direction is introduced by inserting two wedge plates orthogonally in two arms, respectively. One of the wedge plates is split into two parts (parallel part and wedge part); phase shift is produced by moving the wedge part in contact along the parallel part. The moving distance for a 2 pi phase shift is a few millimetres in specific conditions. The wedge plate phase-shifter increases the moving distance for phase shift and makes the control of phase shift relatively easy. We also discuss the lateral shear error and phase shift errors induced by wedge plates. The lateral shear error is small enough to be ignored; the phase shift error is determined mainly by the wedge angle error. Lastly, we give the experimental results of phase-shifting interference fringes in vectorial shear mode.

We proposed a new method of measuring the degree of collimation of laser beam using axial intensity information near paraxial focus. Preceding methods for collimation testing are mainly either based on self-imaging or interferometric techniques. The new method is to employ the diffraction behavior of noncollimated wave in circular aperture diaphragm. The principle of the proposed method and experiment results are presented. Due to simplicity of the method and its low cost, it is a promising method for checking the collimation of laser beam.

The formation of the non-uniformity of the non-volatile volume grating in doubly doped LiNbO3 crystals is studied in detail. We find that the non-uniformity of the grating is mainly caused by strong ultraviolet light absorption, and the average saturation space-charge field is small and the diffraction efficiency is low as a result of the non-uniformity of the grating. In order to optimize the uniformity of the grating, we propose the recording scheme by using two sensitizing beams simultaneously from the two opposite sides of the crystals. Theoretical simulations and experimental verifications are performed. Results show that the well uniformed grating with high diffraction efficiency can be obtained by using this optimization scheme. (c) 2004 Elsevier B.V. All rights reserved.

The photorefractive planar lens for converting a vertical incident plane wave to a lateral-spread spherical wave and vice versa, is suggested. Using the two-beam coupled-wave theory, the coupled wave equations are derived and their half-analytical solutions are also given in terms of an infinite series. The diffraction properties (beam profiles, diffraction efficiency) of the local volume grating in the lens are presented. And the focusing property of the lens is discussed and compared with that of an ideal convergent spherical wave. It is demonstrated that the suggested photorefractive planar lens shows a good focusing effect.

In the inter-satellite laser communication, the diffraction-limit wavefront is required. To test the wavefront, we have developed a Jamin double-shearing interferometer. The interferometer is consists of two Jamin plates to form lateral shearing and four wedge plates to divide the aperture. The laser beam to be test is incident on the first Jamin plate and gives rise to two beams. One is reflected from the front surface of the first Jamin plate, then passes two wedge plates and is reflected from the rear surface of the second Jamin plate. The other is reflected from the rear surface of the first Jamin plate, then passes other two wedge plates and is reflected from the front surface of the second Jamin plate. The two beams are recombined to form the interferogram. For the interferometer, simple phase-shifting method to improve the measurement accuracy of the wavefront by moving four wedge plates is proposed in this paper. When the wedge plates are moved along its surface or in the incidence direction of the interferometer, the optical path difference of two interferometric beams is changed to form phase shift. The added optical path difference introduced by the movement of wedge plates is liner function of displacement, thus the phase-shifting amount is easy to be control. Wedge plates can be moved in four steps with interval of quarter wavelength and the phase can be unwrapped using the four-step phase-shifting algorithm. In experiments, phase-shifting interferograms are obtained. The usefulness of the phase-shifting methods is verified.

Space to ground laser communication is limited by the effects of atmosphere. Differential phase shift keying (DPSK) is suited for high data rate space to ground communication links due to its immunity of the wave front of a beam passing atmospheric turbulence, which carry the information in optical phase changes between bits. The benefit of DPSK over OOK is the 3 dB lower optical signal to noise ratio to reach a given bit error rate (BER) using a balanced receiver. An aperture-matched phase-compensated DPSK receiver with a 90° hybrid is proposed here. The receive optics are based on free-space optics. A Mach-Zehnder delay interferometer is used for differential delay which is equal to the bit period. The input pupil is imaged onto the same place by two afocal systems composed of 4f imaging lenses. The optical path difference is stabilized to a faction of the wavelength with a fine phase adjustment which is measured by a 2×4 90° optical hybrid and closed loop electric circuit. The design and experiments are given in this paper. optical hybrid and closed loop electric circuit. The design and experiments are given in this paper. optical hybrid and closed loop electric circuit. The design and experiments are given in this paper.

A demonstrator of synthetic aperture imaging ladar (SAIL) is constructed with the maximum aperture O300mm of antenna telescope. This demonstrator can be set with a rectangular aperture to produce a rectangular footprint suitable for scanning format with a high resolution and a wide strip. Particularly, the demonstrator is designed not only for the farfield application but also for the verifying and testing in the near-field in the laboratory space. And a 90 degree optical hybrid is used to mitigate the external phase errors caused by turbulence and vibration along line of sight direction and the internal phase errors caused by local fiber delay line. This paper gives the details of the systematic design, and the progresses of the experiment at a target distance around 130m.

The time-delay self-homodyne interferometric detection used in 2×4 90° optical hybrid for free-space optical communication is presented. An asymmetric Mach-Zehnder interferometer splits the received signal into two paths and recombines these two signals after a optical path difference. A balanced receiver follows the interferometer as a multiplier. The modulation contrast in the interferometer depends on the interference of identical wave-fronts, not on the quality of the wave-front itself. So it does not require wave-front compensation techniques, a local oscillator laser nor does it need frequency locking. The scheme can eliminate the effect of wave-front deformation on coherent detection in free-space optical communication effectively.

There is large aperture and diffraction-limited laser beam in the space laser applications such as laser communication. Laser wavefront can be measured by shearing interferometer or Shark-Hartmann sensor etc. Large-Optics shearing interferometer based on Mach-Zehnder plate structure has been manufactured to differentially analyze the laser wavefront from two parts of aperture-divided fringes. One of six optical plates of the interferometer is divided to the up part and the down. The precision of measurement is higher than the full aperture design. It is suitable for the diameter below 290mm with the changeable shear amount from 1mm to 150mm. There are two sets of collimators used for the parallel of the plates. Another single-mode 635nm laser collimator which is measured through double-shearing plate before is serving as a standard wavefront of 150mm diameter. One path of the interference is changed with precise adjustment unit in several microns that the interference may be happened between equal optical path reflection and the other. It can be used for widely tunable laser and other laser system which has short coherent length. The apparatus and the experiments are explained in detail in this paper. Many systems of different quality and diameter and coherent length are measured by the large-optics shearing interferometer. The experimental wavefront results are fitted to Zernike polynomial and the Zernike coefficients are derived.

The design of an optical birefringent 90° hybrid for coherent receiver in free-space optical communication system is presented. The bulk optical design of 2×4 90° hybrid is a six-port device with two inputs and four outputs. For the balanced receiver configuration two pairs of 180° phase shifted outputs are obtained and one pair has a phase shift of 90° with respect to the other. The optical birefringent 90° hybrid includes two pairs of birefringent plates, an analyser plate and a λ/8 wave plate. The scheme of phase compensation is also presented.

A fully 2-D synthetic aperture imaging ladar (SAIL) demonstrator is designed and being fabricated to experimentally investigate and theoretically analyze the beam diffraction properties, antenna function, imaging resolution and signal processing algorithm of SAIL. The design details of the multi-purpose SAIL demonstrator are given and, as the first phase, a laboratory-scaled SAIL system based on bulk optical elements has been built to verify the principle of design, which is similar in construction to the demonstrator but without the major antenna telescope. The system has the aperture diameter of about 1mm and the target distance of 3.2m.

The instantaneous preferential domain nucleation effect of the z-cut hafnium-doped congruent LiNbO 3 crystal is investigated. The beam from an Ar-ion laser with 514 nm wavelength is focused on z surface. Two incidence schemes are performed: (1) irradiating near and focusing on the +z surface; (2) irradiating near and focusing on the -z surface. The digital holographic interferometry is used in investigating the visible laser-induced domain nucleation in hafnium-doped congruent LiNbO 3 crystal, and reconstructs the phase shift of new domain. From the investigation of phase shift induced by the domain inversion, the analysis of domain nucleation is performed. When the electric field exceeds a certain threshold value, the preferential domain nucleation is achieved instantaneously at the focal spot during the combined actions of irradiation and external fields. The nucleation fields have a systematic decrease with increasing laser intensity, and reach an effective saturation at higher intensities. The reduction proportions obtained in the second scheme are lower than those in the first one with the same intensity, and the saturation values at higher intensities are the same in both schemes. We attribute the instantaneous effect of laser-induced domain nucleation to the space charge field, and the saturation value at higher intensities is related to the saturation of the space charge field. The formation of instantaneous effect and corresponding physical explanation based on space charge field are present.

The phase-mapping of domain wall kinetics under the uniform st eady-state electric field is achieved and investigated in the LiNbO 3 crystals by the digital holographic interferometry. We obtained the sequences of reconstructed three-dimensional and two-dimensional wave-field phase distributions during the electric poling in the congruent and near stoichiometric LiNbO 3 crystals. The phase-mapping of domain wall mo tions in the two crystals are obtained. Both the phase relaxation and the pinning-depinning mechanism are observed during the domain wall motion. The residual phase distribution is observed after the high-speed domain wall motion. The corresponding analyses and discussions are proposed to explain the phenomena. Keywords: phase-mapping, domain wall kinetics, lithium ni obate, digital holographic interferometry 1. Introduction With the large electro-optic and nonlinear optical coefficients, lithium niobate has become one of the most important and widely applied optical materials. The domain engineering in the LiNbO

A method to measure the frequency change of the tunable laser based on a Jamin shearing interferometer is proposed. The Jamin shearing interferometer is composed of two Jamin plates, two shearing plates and a retardation plate. The tunable laser beam is split into two beams by one Jamin plate. The retardation plate is placed in one of two beams to provide additional phase retardation. Two beams pass two shearing plates, respectively, and are combined by the other Jamin plate to form lateral shearing interferogram. In course of tuning, interference fringes are shifted as a whole and its spacing is kept constant. By detecting displacement of fringes, the frequency change of the laser is obtained. In experiments, we observed that interference fringes were shift periodically when the laser diode was modulated sinusoidally. A series of interferogram in which fringes are shifted as a whole with the variation of the frequency are obtained. The feasibility of the method is verified.

Synthetic aperture imaging ladar (SAIL) used a series of pulses in which the optical frequency was swept linearly in time over a bandwidth greater than several gigahertz. The linearity of such broadly tunable sources is often poor which is leading to phase errors. Many methods are adopted to correct for quadratic and higher-order phase errors such as the reference channel or algorithm for unmatched channel of Aerospace and the reference interferometer of Naval Research Laboratory. If the real value of frequency swept quasi-linearly is measured another direct way to mitigate the waveform linearity problem can be developed. At first the frequency curve is measured with Fabry Perot fiber interferometer. Experiment and results are explained in detail in this paper. The quadratic and higher-order terms of frequency swept are calculated. They may be used to deduce the phase errors directly later. At the same time the wavefront is also measured by a Jamin shearing interferometer through the fringe analysis.

To study the apoptotic effects of arsenic trioxide on human coronary smooth muscle cells (HCSMCs).HCSMCs were cultured and randomly divided into 5 groups to be treated by arsenic trioxide of the concentrations 1.0, 2.0, 3.0, 4.0, and 5.0 micromol/L for 48 h. Cell growth curve was drawn by MTT method. DNA electrophoresis was used to observe the apoptosis. Western blotting was conducted to examine the protein expression of Bax, an apoptosis-promoting gene, and Bcl-2, an apoptosis-inhibiting gene. Other HCSMCs were cultured with 4.0 micromol/L arsenic trioxide for 48 h, then transmission electron microscopy was used to observe the ultra-structure and TUNEL was used to detect the percentage of apoptotic cells. HCSMCs not treated with arsenic trioxide were used as control group.Arsenic trioxide of different concentrations inhibited the proliferation of HCSMCs dose and time-dependently. When the concentration of arsenic trioxide was 5.0 micromol/L the number of living cells was (4.41 +/- 0.10) x 10(5)/ml, significantly lower than that of the control group [(30.11 +/- 0.93) x 10(5)/ml, P0.05]. Apoptosis bodies were observed under the transmission electron microscope. DNA electrophoresis showed hazy ladders, especially when the concentrations were 3.0 - 4.0 micromol/L. When the concentration was 5.0 micromol/L the number of necrotic cells increased remarkably and apoptosis became less significant. TUNEL showed that the apoptotic cells increased from 16.0% +/- 3.1% to 38.7% +/- 2.7% (P0.05). MTT test showed that arsenic trioxide decreased the absorbance of HCSMCs dose and time-dependently. Western blotting showed that the Bcl-2 expression was decreased and the expression of Bax increased after treatment of arsenic trioxide.Arsenic trioxide exerts an apoptotic effect on HCSMCs.

The double threshold effect of ultraviolet laser-induced preferential domain nucleation in near stoichiometric LiTaO3 is observed. The continuous ultraviolet laser beam (351 nm) is focused on the -z surface of the wafer, and the homogeneous electric field is applied simultaneously antiparallel to the direction of spontaneous polarization along the z axis. The double threshold effect includes both the primary and the secondary thresholds. The primary threshold is the minimum intensity to achieve the instantaneous preferential domain nucleation within the focus by the combined action of irradiation and electric fields. Below the dark nucleation field, the instantaneous preferential domain nucleation is achieved within the illuminated area when the intensity exceeds the primary threshold. The experiments prove that the domain inversion can be locally controlled by the laser irradiation. The secondary threshold is the minimum intensity to achieve the memory effect without any irradiation within the original focus. The memory effect of preferential nucleation is observed when the intensity is below the primary threshold and above the secondary threshold. The preferential domain nucleation of memory effect is investigated. The different physical explanations are presented for the instantaneous effect and memory effect. The space charge field created by the photoionization carriers is thought to be responsible for the instantaneous effect. The explanation based on the formation and transformation of extrinsic defect is presented for the memory effect.

There is transmitting optics of 250mm aperture with about 8 microradians in SILEX system. This is often large aperture and diffraction-limited laser beam in the laser communications. Large-Optics white light interferometer using double-shearing structure has been submitted to analysis the laser wavefront before. Six optical plates of 490 millimeters apertures are manufactured now one of which is also aperture-divided so that the precision of measured wave front is higher than the full aperture design. It is suitable for measurement of minimum diffraction-limited laser wave front and any wavelength. The interference is happened between equal optical path of the reflection and the other. The plates are the basic structures which are precisely parallel or perpendicular needed for either two plates. There are several tools equipped with the interferometer including white light test source and collimators and so on to confirm the precision of several seconds angle. The apparatus and application is explained in detail in this paper. The adjustment is important for the realization of white light test.

Due to the improved receiver sensitivity and wavelength selectivity, coherent detection became an attractive alternative to direct detection in inter-satellite laser communications. A novel method to coherent detection of position errors information is proposed. Coherent communication system generally consists of receive telescope, local oscillator, optical hybrid, photoelectric detector and optical phase lock loop (OPLL). Based on the system composing, this method adds CCD and computer as position error detector. CCD captures interference pattern while detection of transmission data from the transmitter laser. After processed and analyzed by computer, target position information is obtained from characteristic parameter of the interference pattern. The position errors as the control signal of PAT subsystem drive the receiver telescope to keep tracking to the target. Theoretical deviation and analysis is presented. The application extends to coherent laser rang finder, in which object distance and position information can be obtained simultaneously.