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To explore the improving method of mechanical properties on laser welding-brazing joints for aluminum alloys and steel, a novel laser welding connection process is proposed to efficiently improve bonding strength via surface texture and AlSi12 precoating for 6061 aluminum alloys and DP600 dual-phase steel. The role of this method in improving joint property was evaluated by the microstructure, interface structure, and wetting morphology. The results indicated that a mechanical pin structure is formed between the two materials to ensure that the two materials lock tightly. The average joint strength is 171 MPa using the surface grooves with appropriate line spacing and the preset filling metal, which is 24.5% higher than the untreated direct welded joint. Furthermore, the morphology of the cross section of the joints exhibited better wetting and spreading performance. The analysis indicated the joint strength enhancement via the combination of metallurgical bonding and mechanical interlocking. The proposed method provides an innovative technique to facilitate the manufacturing process for joining dissimilar materials and the quality of products.

This paper studies a Stackelberg differential game between an upstream region and a downstream region for transboundary pollution control and ecological compensation in a river basin and increases the number of pollutants assumed in the model to multiple. Emission and green innovation investment between upstream and downstream regions in the same basin is a Stackelberg game, and the downstream region provides economic compensation for green innovation investment in the upstream region. The results show that there is an optimal ecological compensation rate, and a Pareto improvement result can be obtained by implementing ecological compensation. Increasing the proportion of ecological compensation can improve the nonvirtuous chain reaction between green innovation investment cost, pollutant transfer rate, and ecological compensation rate. Therefore, it is necessary to establish a joint mechanism composed of the government and the market and formulate a reasonable green innovation subsidy scheme according to the actual situation of the basin, so as to restrict the emergence of this “individual rational” behavior. For river basin areas that can establish a unified management department and organize the implementation of decision-making, the cooperative game is a very effective pollution control decision.

Many studies have been published to assess the association about dietary protein intake on the risk of pancreatic cancer, but with inconsistent result. This meta-analysis aimed to evaluate whether protein intake could affect the risk of pancreatic cancer. A systematic literature search was performed in PubMed, EMBASE and Web of Science up to October 1, 2019. Pooled relative risks (RR) and 95% confidence intervals (CI) were calculated using a random-effect model. A total of 14 studies (12 case-control studies and two cohort studies) were included. Overall, total protein intake had no significant association on the risk of pancreatic cancer (RR = 1.02, 95%CI= 0.85-1.22, I

This paper analyzes a dynamic Stackelberg differential game model of watershed transboundary water pollution abatement and discusses the optimal decision-making problem under non-cooperative and cooperative differential game, in which the accumulation effect and depreciation effect of learning-by-doing pollution abatement investment are taken into account. We use dynamic optimization theory to solve the equilibrium solution of models. Through numerical simulation analysis, the path simulation and analysis of the optimal trajectory curves of each variable under finite-planning horizon and long-term steady state were carried out. Under the finite-planning horizon, the longer the planning period is, the lower the optimal emission rate is in equilibrium. The long-term steady-state game under cooperative decision can effectively reduce the amount of pollution emission. The investment intensity of pollution abatement in the implementation of non-cooperative game is higher than that of cooperative game. Under the long-term steady state, the pollution abatement investment trajectory of the cooperative game is relatively stable and there is no obvious crowding out effect. Investment continues to rise, and the optimal equilibrium level at steady state is higher than that under non-cooperative decision making. The level of decline in pollution stock under finite-planning horizon is not significant. Under the condition of long-term steady state, the trajectories of upstream and downstream pollution in the non-cooperative model and cooperative model are similar, but cooperative decision-making model is superior to the non-cooperative model in terms of the period of stabilization and steady state.

Background To investigate the effect of bowel resection combined with fluoroscopic-assisted balloon thrombectomy for small bowel infarction caused by acute mesenteric venous thrombosis (AMVT). Methods Between June 2016 and August 2017, nine patients (seven males and two females; range, 40–73 years; mean, 55.11 ± 10.08 years) with small bowel infarction caused by AMVT underwent bowel resection combined with fluoroscopic-assisted balloon thrombectomy. The demographics, risk factors, therapeutic effect, complications, mortality, and follow-up of the study population were assessed. Results The effective rate was 100% with substantial clinical improvement in symptoms. All patients underwent small bowel resection with primary anastomosis. The length of bowel resection ranged from 60 to 170 cm (108.67 ± 35.05). In none of the cases there was surgery with second look. The patients were discharged 13–42 days (20.11 ± 8.75) after admission without perioperative complication or death. The follow-up period was 8–21 months (12.89 ± 4.65), and the follow-up rate was 100%. All patients returned to normal activities, regained lost body weight, and remained asymptomatic during the follow-up period. Conclusions The combination therapy of bowel resection and fluoroscopic-assisted balloon thrombectomy is technically feasible and may be beneficial for small bowel infarction caused by AMVT in removing a thrombus efficiently, relieving symptoms rapidly, averting second-look surgery, lowering extensive surgical resections, and improving the prognosis.

This paper extends the recent work of Shibata from static perspective to dynamic perspective, presents a differential game model of pollution abatement RD the pollution abatement R&D investment spillovers have some positive influence on optimal cooperative R&D investment while make the optimal noncooperative R&D investment decrease.

Calcific aortic valve disease (CAVD) is a complex heart valve disease involving a wide range of pathological changes. Emerging evidence indicates that osteogenic differentiation of human aortic valve interstitial cells (hAVICs) plays a key role in valve calcification. In this study, we aimed to investigate the function of miR‐638 in hAVICs osteogenesis. Both miRNA microarray assay and qRT‐PCR results demonstrating miR‐638 was obviously up‐regulated in calcific aortic valves compared with non‐calcific valves. We also proved that miR‐638 was significantly up‐regulated during hAVICs osteogenic differentiation. Overexpression of miR‐638 suppressed osteogenic differentiation of hAVICs in vitro, whereas down‐regulation of miR‐638 enhance the process. Target prediction analysis and dual‐luciferase reporter assay confirmed that Sp7 transcription factor (Sp7) was a direct target of miR‐638. Furthermore, knockdown of Sp7 inhibited osteogenic differentiation of hAVICs, which is similar to the results observed in up‐regulation miR‐638. Our data indicated that miR‐638 plays an inhibitory role in hAVICs osteogenic differentiation, which may act by targeting Sp7. MiR‐638 may be a potential therapeutic target for CAVD.

Xianming Wang,* Zhengtong Zhou,* Tao Zhang,* Minghai Wang, Rongwei Xu, Shiyong Qin, Shuguang Zhang Department of General Surgery, Qianfoshan Hospital Affiliated to Shandong University, Shandong 250014, China *These authors contributed equally to this work Introduction: Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. This study aimed to investigate the expression patterns of microRNA-664 (miR-664) in HCC tissues and cells, and assess its clinical significance and functional role in HCC. Patients and methods: One hundred and thirty-four paired HCC and non-cancerous tissues were collected from patients who underwent surgery in Qianfoshan Hospital affiliated to Shandong University (Shandong, China) between 2009 and 2012. Expression of miR-664 was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Prognostic value of miR-664 in HCC was evaluated using Kaplan–Meier survival analysis and Cox regression analysis. Cell proliferation was analyzed using the CCK-8 assay, and cell migration and invasion of HCC cells was evaluated by the Transwell assay. Results: Expression of miR-664 was significantly upregulated in HCC tissues and cells when compared with the normal controls (all P

In this work, a lab-scale membrane system was developed to accommodate angular vibrations with a hollow fiber module. A series of filtration experiments were designed and implemented to investigate the effects of angular vibrations on fouling by various algae-derived foulants, including algal cells, debris, extracellular organic matter (EOM), and intracellular organic matter (IOM). The experimental results indicated the effects of angular vibrations on fouling mitigation at the frequency of 2 Hz in the following order: algal cells (~ 97.4%) > debris (~ 93.6%) > IOM (~ 81.8%) > EOM (~ 52.3%). The vibrations mainly targeted the cake layer formed by these foulants, but was ineffective for pore blocking which constituted a large portion of EOM fouling. Although the fouling rates were accelerated during the normal ultrafiltration of the combined foulants, the effects of angular vibrations continued to be impressive (67.8–92.6%). This was because the cake layer formation was the dominant fouling mechanism. Furthermore, the vibrations were found to improve the organic removal by alleviating concentration polarization. In this paper, quantitative analysis is presented to demonstrate the potential of angular vibrations to control algal fouling with the relatively low energy consumption of 0.034 mW.

Objective To evaluate the feasibility and efficacy of preoperative hyperselective transarterial embolization in carotid body tumor resection. Methods Retrospectively analyze the clinical feature, imaging examination, treatment strategy and prognosis of 29 carotid body tumor patients from January 2006 to January 2016. According to whether to carry out the pre-operative transarterial embolization, the patients were classified into embolization group and non-embolization group. The blood loss, operative time and perioperative complications were compared between the 2 groups. Results 29 carotid body tumors were resected. The median of blood loss was 80 mL in embolization group and 200 mL in non-embolization group, the difference was statistically significant (P = 0.001). The median of operative time was 120 min in embolization group and 160 min in non-embolization group, the difference was statistically significant (P = 0.006). No death, paralysis or ectopic embolism occurred in the study population. 4 patients in embolization group and 4 in non-embolization group suffered from cranial nerve injury. Conclusion Surgical resection of carotid body tumor is safe and reliable, which is the first choice in the treatment of carotid body tumor. Preoperative transaterial hyperselective embolization can significantly reduce blood loss and shorten operative time, but it dose not decrease the incidence of cranial never injury.

We present our experience with endovascular surgery for recurrent varicose veins (RVV) of the lower limbs combined with the iliac vein compression syndrome (IVCS).This study was a retrospective analysis of 6 patients with RVVs combined with IVCS who were admitted to our hospital between January 2007 and December 2014. Transfemoral venography was performed to confirm IVCS. Balloon dilation and stent placement were successful in all 6 patients. The varicose veins were treated by traditional surgery after the endovascular therapy. The visual analog pain scale (VAS) score and venous clinical severity score (VCSS) were collected before surgery and at 6-months follow-up, and were analyzed using the paired student t-test. Patency of the iliac vein was assessed via duplex Doppler ultrasound.The rate of technical success was 100%. There was a significant (p .001) improvement in VCSS postoperatively. During the 6-month follow-up period, no RVVs were observed and the rate of iliac vein patency was 100%. Importantly, VAS ratings also decreased significantly (p .001) during the follow-up.Endovascular surgery for IVCS combined with traditional surgery focused on varicose veins is an effective procedure for treating RVVs of the lower limbs associated with IVCS within 6 months.

In lightweight engineering, mechanical metamaterials (MMs) are suitable for additive manufacturing (AM) due to their geometry complexity. However, it is inevitable to bring about mechanical deviation and local yield for MMs infilled lightweight structures. In the current work, MMs mapped structures, named as MMs-TO-PSLs, are proposed. The design domain is divided into core-region, intermediate-region, and solid-region. Core-regions derived from topology optimization (TO) are mapped with MMs, of which the [1 0 0] orientations are aligned with the normal directions of principal stress lines (PSLs). The intermediate-regions are infilled with ribbons according to PSLs. The solid regions are allocated to stress concentrated areas. Finally, near isotropic mechanical response is achieved in core-region from anisotropic MMs, and the serious local deformation is eased. To validate such approach, the mapping strategy is carried out on a beam subjected to three-point bending. Metallic MMs-TO-PSLs and MMs infilled uniform lightweight structure are fabricated by selective laser melting (SLM). Elastoplastic simulations with ductile failure model are proposed to investigate the strengthen mechanism of MMs-TO-PSLs. Experimental and numerical results confirmed the ultimate strength of MMs-TO-PSLs can be 40% larger than conventional MMs infilled uniform structures.

Background: Drug-eluting balloon (DEB) and drug-eluting stent (DES) have been proposed for the treatment of infrapopliteal artery disease. We performed a systematic review and meta-analysis of the current available studies investigating outcomes of DEB and DES in the treatment of infrapopliteal artery disease. Methods: Multiple databases were systematically searched to identify studies investigating the outcomes of DEB and DES in the treatment of patients with infrapopliteal artery disease. The quality of studies was assessed by Cochrane Collaboration method. The demographic data, risk factors, outcomes, and antiplatelet strategy were extracted. Results: Nine studies were identified with 707 and 606 patients in DEB/DES and standard percutaneous balloon angioplasty (PTA)/bare metal stenting (BMS) group, respectively. The risk of target lesion revascularization (TLR; odds ratio [OR] = 0.38, 95% confidence interval [CI]: 0.23-0.63, P < .01), restenosis rate (OR = 0.30, 95% CI: 0.18-0.50, P < .01), and amputation rate (OR = 0.49, 95% CI: 0.29-0.83, P < .01) significantly decreased in the DES group. The overall survival (OR = 0.86, 95% CI: 0.56-1.32, P = .50) was similar in DES and standard PTA/BMS group; TLR (OR = 0.59, 95% CI: 0.32-1.09, P = .09), restenosis rate (OR = 0.49, 95% CI: 0.11-2.14, P = .35), amputation rate (OR = 1.32, 95% CI: 0.51-3.40, P = .57), and overall survival (OR = 1.40, 95% CI: 0.72-2.71, P = .32) were similar in DEB and standard PTA group. Conclusion: The present meta-analysis suggests that compared with standard PTA/BMS, DES may decrease the risk of clinically driven TLR, restenosis rate, and amputation rate without any impact on mortality. However, DEB has no obvious advantage in the treatment of infrapopliteal disease. Due to the limitations of our study, more randomized controlled trials, especially those for DEB, are necessary.

Considering the fact that transboundary pollution control calls for the cooperation between interested parties, this paper studies a cooperative stochastic differential game of transboundary industrial pollution between two asymmetric nations in infinite-horizon level. In this paper, we model two ways of transboundary pollution: one is an accumulative global pollutant with an uncertain evolutionary dynamic and the other is a regional nonaccumulative pollutant. In our model, firms and governments are separated entities and they play a Stackelberg game, while the governments of the two nations can cooperate in pollution reduction. We discuss the feedback Nash equilibrium strategies of governments and industrial firms, and it is found that the governments being cooperative in transboundary pollution control will set a higher pollution tax rate and make more pollution abatement effort than when they are noncooperative. Additionally, a payment distribution mechanism that supports the subgame consistent solution is proposed.

In this work, the effect of powdered activated carbon (PAC) on fouling by algal solution during ultrafiltration using two different PAC dosing strategies: pre-depositing PAC onto the membrane surfaces or the conventional addition of PAC to the bulk feed. The addition of PAC by either mode improved the removal of extracellular organic matter (EOM) from the algal solution. However, for the pre-deposition mode, increasing the PAC amount from 0 to 2.1 g caused a steady increase in the membrane fouling rate (from 0.4 to 1.4 kPa/h), whereas the opposite result (from 0.4 down to 0.1 kPa/h) was found for the conventional PAC dosing mode. This is likely due to the differences in the initial arrangement of algal cells and PAC along the cake layer depths. The pre-deposited PAC avoided contact between cells and membranes, but aggravated the deformation of the cells and hindered their back-transport to the bulk solution. Furthermore, although the effect of PAC on the EOM fouling was marginal, there were highly synergistic effects when cells and EOM were present together in the PAC pre-deposition mode. Changes in the PAC dosing mode also altered the PAC-membrane interactions, inducing a higher cleaning efficiency of backwash for the conventionally-dosed PAC from membrane surfaces than that for the pre-deposited PAC.

The treatment for bilateral carotid stenosis (BCS) is challenging, and the optimal treatment strategy is not clear. We report our experience of treating 8 patients with BCS by simultaneous carotid endarterectomy (CEA) and carotid stenting (CAS), thereby providing an alternative for vascular surgeons.Between October 2010 and August 2014, 8 patients (5 males and 3 females; range, 53-82 years; mean, 69 ± 8.8 years) underwent simultaneous CEA and CAS in our hospital. CEA before CAS was done in 5 patients, and CAS before CEA was done in 3 patients. One patient also underwent simultaneous coronary artery bypass grafting due to unstable angina. Intraoperative transcranial Doppler ultrasonography, carotid shunts, patches, and embolic protection devices were used in all patients. Instances of hyperperfusion syndrome (HPS), hemodynamic depression, stroke, myocardial infarction (MI), and death were recorded.All patients completed the procedure. One patient developed postprocedural HPS. After systemic treatment, he recovered completely. There were no deaths, major and/or minor strokes, or MI, nor did any patient exhibit lower palsy in cranial nerves in the perioperative period (30 days) or on clinical follow-up (3 and 6 months). We observed no restenosis and no recurrent symptoms during follow-up.After careful preoperative assessment and preparation, simultaneous CEA and CAS for high-grade BCS may be considered as an alternative management strategy in carefully selected patients.

The ultrasonic-assisted water confined laser micromachining is a novel micromachining method. This paper reports the experimental studies of ultrasonic power and water layer thickness on the laser (1064 nm nanosecond pulse laser) micromachining of silicon. Besides, this reports a systematic discussion on the influence of the acoustic streaming and bubbles (induced by laser) dynamic change on the machining process. The acoustic streaming and flow pattern under different ultrasonic power application and different water layer thickness using Particle Image Velocimetry (PIV). A finite element (FE) heat transfer model was employed to gain a better understanding of the effect of the acoustic streaming velocity on the temperature field change in laser processing. The bubbles (induced by laser) dynamic behavior is observed by the high-speed camera. The results showed that the ultrasonic-assisted laser ablation can yield much higher the material removal rate than laser cutting in water without ultrasonic-assisted. Besides, the increase in the ultrasonic power helps to improve the etching efficiency but is not apparent. When the water layer thickness is 1 mm, the cutting effect is significantly different from the laser ablation in the other three water layers. Through the PIV images and simulate results, it has been found that the influence of acoustic streaming on heat transfer in laser processing is small. Through high-speed camera imaging observations, the dynamic change of bubbles is an essential mechanism for the enhanced material removal rate and affect the machining performance in this study. This study helps understand the mechanism of ultrasonic-assisted water confined laser micromachining better and promoting this technique potential application in the micromachining of hard brittle materials.

Background: Endothelial cell damage is an important pathophysiological step of restenosis after angioplasty and stenting. Cell transplantation has great therapeutic potential for endothelial recovery. We investigated the effect of transplanting endothelial progenitor cells (EPCs) derived from human early fetal aortas in rat injured arteries. Methods: The carotid arterial endothelium of Sprague-Dawley rats was damaged by dilatation with a 1.5 F balloon catheter, and then EPCs derived from human early fetal aortas (

This investigation compared the effects of pre-deposited and pre-mixed powdered activated carbons (PACs) in submerged ultrafiltration membrane reactors on the distribution of extracellular organic matter (EOM) and its contribution to algal fouling during the filtration of algae-rich water. Experimental results indicate that pre-mixed PAC mitigated algal fouling, whereas pre-deposited PAC exhibited the opposite effect. The porous fouling layer in the pre-mixed case favored the retention of rejected EOM in the concentrated solution owing to a high backward migration rate. Conversely, the dense fouling layer in the pre-deposited case impeded the backward diffusion of EOM, which caused the majority of the rejected EOM to accumulate on the surface and at the bottom of the fouling layer. This difference in EOM distribution led to different cleaning efficiencies. Physical cleaning easily removed both algal cells and pre-mixed PAC from the membrane surfaces, whereas physical and chemical cleanings were both ineffective for pre-deposited PAC, owing to the stronger PAC-EOM attractive force and the NaClO-induced change in the chemical bonds of the PAC and even the membranes. Moreover, decreased algae growth rates were observed in the reactors with PAC as a result of changes in the illumination and the cake layer structure, which could further intensify the contrast between the effects of pre-deposited and pre-mixed PACs on fouling.

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.

The frame of a laser diode transmitter for intersatellite communication is concisely introduced. A simple, novel and visual method for measuring the diffraction-limited wavefront of the transmitter by a Jamin double-shearing interferometer is proposed. To verify the validity of the measurement, the far-field divergence of beam is additionally rigorously analysed in terms of the Fraunhofer diffraction. The measurement, the necessary analyses and discussion are given in detail. By directly measuring the fringe widths and quantitatively interpreting the interference fringes, the minimum detectable wavefront height (DWH) of the wavefront is only 0.2 gimel (the distance between the perfect plane wavefront and the actual wavefront at the transmitting aperture) and the corresponding divergence is only 65.84 mu rad. This indicates that the wavefront approaches the diffraction-limited condition. The results show that this interferometer is a powerful tool for testing the semiconductor laser beam's wavefront, especially the diffraction-limited wavefront.

Background: The optimal management of patients with concomitant carotid and coronary artery disease remains controversial. Methods: The records of 113 consecutive patients who underwent either simultaneous carotid endarterectomy (CEA) and off-pump coronary artery bypass grafting (CABG) (CEA/CABG, n=15) or offpump CABG alone (CABG, n=98) between January 2013 and July 2015 were reviewed. We retrospectively analyzed the baseline characteristics and 30-day results of both groups. Results: The two groups were similar with regard to age, gender, hypertension, diabetes mellitus, hyperlipidemia, smoking, chronic renal failure, prior MI, previous PCI, ejection fraction, LM or triplevessel disease, stable and unstable angina. Peripheral vascular disease was more prevalent in the CEA/CABG group (53.3% vs. 6.1%, P vs. 24.5%, P 0.05). No death within 30 days occurred in both groups. There was no significant different between the two groups in postoperative complications [stroke, myocardial infarction (MI), transient ischemic attack (TIA), atrial fibrillation/atrial flutter, cardiac tamponade, cardiac arrest, pulmonary infection, Wound infection, and bleeding requiring re-operation] (all P>0.05). The cumulative complications at 30 days was 3 (20%) in the CEA/CABG group compared with 16 (16.3%) in the CABG group (P=0.72). The differences in total intubation time, intensive care unit (ICU) stay and hospital stay were also not statistically significant (all P>0.05). Conclusions: Our results showed that addition of CEA to CABG would not increase the risk of mortality and morbidity relative to patients underwent CABG alone. Our study adds to the controversy of simultaneous CEA/CABG procedure. Large-scale, multi-center, randomized clinical trials are required to further evaluate the outcomes of simultaneous CEA/CABG.

Background: The optimal management for patients with concomitant severe coronary artery disease (CAD) and carotid artery stenosis (CAS) remains controversial. Methods: One hundred and two solely carotid endarterectomy (CEA) patients were matched to 34 synchronous CEA and coronary artery bypass grafting (CABG) patients according to the propensity score during 7 years. We retrospectively analyzed the baseline characteristics and 30-day results of both groups. Results: The two groups were similar with regard to age, sex, the degree of CAS, the incidence of hypertension, diabetes mellitus (DM), smoking, hyperlipidemia and symptomatic CAS. Higher incidence of contralateral >70% CAS occurred in synchronous CEA/CABG group (29.4% vs . 13.7%, P=0.038). More CAD was present in synchronous CEA/CABG group (12.7% vs . 100%, P vs . 0.55±0.09, P vs . 1.98±1.67, P Conclusions: Our study suggested that the 30-day mortality and morbidity rate of synchronous CEA/CABG was comparable to solely CEA. Our results add to the controversy of the outcomes of synchronous CEA/CABG procedure. Further prospective randomized controlled trial is needed to definitely evaluate the results of synchronous CEA/CABG.

Predicting traffic flow efficiently to encourage driver to avoid the sections which are going to have traffic jams is a good approach to deal with traffic congestion. Conventional prediction methods focused on specific information (e.g., speed, density, flux, and so on). However, they will consume a lot of time and storage space. This paper proposes a novel prediction approach by analyzing the aggregated information of data streams to avoid unnecessary time and storage consumption. Evaluation shows that compared with existing similar approach ES (Exponential Smoothing), this new approach can adjust its smoothing factor based on historical values and outperform in prediction results.

In the field of intersatellite communication, laser beam transmitted from the optical terminal is required to be highly collimated with diffraction-limit divergence. Then, the maximal wavefront aberration at the edge of exit pupil is about 0.3λ. In order to measure the diffraction-limit wavefront, we present a whole-field double-shearing interferometer based on double-shearing theory. In this paper, firstly, the principle and configuration of the interferometer is introduced. Then the theory of double shearing is discussed. At the same time, we extend the applications of the interferometer. Lastly, we present the simulations of interference fringes with different primary aberrations and give the experimental results for the measurement of diffraction-limit wavefront.

In this paper, we give the far-field diffraction theory for calculating the divergence by using the superposition of Gaussian beams instead of the aperture function and obtain the explicit express for calculating the beam divergence. We analyze in detail the influence of the diffraction adding defocus aberrations upon the transmitter's divergence and get the simulated result. These researches are useful to system design and give us some suggestions of avoiding the influence of the aberrations and the diffractions on the transmitter.

Because PAT (pointing-acquisition-tracking) parameters and integrated technical specifications of laser communication terminals for inter-satellite link must be pre-verified and assessed thoroughly on a ground-based test-bed before launched into the space, it is necessary to develop a system as a primary part of the test bed to simulate the relative trajectory between the satellites. In this paper, an original high-precision satellite relative-trajectory simulating servosystem is introduced in detail as well as its structures and characteristics. The system is used to simulate the motion of relative-trajectory between satellites in different orbits. The principle of the system is to import the data of two satellites’ orbits into a computer-based control system in advance. After processed and analyzed, the data is transformed into the angular displacement of the servomotor which drives the gimbal directly. The angular displacement of the two axes of the gimbal can simulate precisely the relative-trajectory, namely elevation angle and azimuth angle of the two satellites in communication. A laser communication terminal mounted on the gimbal then performs the PAT mechanisms to evaluate the system’s capacity.

The support schemes and thermoelastic deformation of 460-mm diameter interferometer mirrors are studied by means of finite element method. The surface deformation and stress distribution in a variety of support schemes are analyzed. By comparison, the band support with 180°wrap angle and a dentiform rubber-lined strip is accepted to be the optimum. In the optimal support scheme, the thermoelastic deformation analyses for mirrors are carried out at specified thermal gradients (axial, radial, circumferential temperature differences). The contours of surface deformation and the transmitted wavefront distortion are presented respectively. According to the results, it is clear that the influence of thermal effects is much greater than the ones of mechanical forces. Lastly, some suggestions are given to eliminate the effects of thermal turbulence.

We report the formulation of an ABCD matrix for reflection and refraction of Gaussian light beams at the surface of a parabola of revolution that separate media of different refractive indices based on optical phase matching. The equations for the spot sizes and wave-front radii of the beams are also obtained by using the ABCD matrix. With these matrices, we can more conveniently design and evaluate some special optical systems, including these kinds of elements. (c) 2005 Optical Society of America