38 research outputs found

    Safety and efficacy of precision hepatectomy in the treatment of primary liver cancer

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    Abstract Background The aim of this study was to investigate the safety and efficacy of precision hepatectomy in the treatment of primary liver cancer. Methods An randomized controlled trial of 98 patients with primary liver cancer admitted to our hospital from February 2020 to February 2021 were analyzed for the study, and they were divided into 49 cases each in the control group (conventional hepatectomy) and the study group (precision hepatectomy) according to the different surgical methods. The surgical condition, complications and follow-up results of the two groups were counted, and the liver function and immune function of the two groups were observed before and 1 week after surgery. Results The operation time, intraoperative bleeding, hospitalization time and anal venting time in the study group were less than those in the control group (P  0.05). Conclusion Precision hepatectomy can effectively treat primary liver cancer with high safety and could be promoted in clinical practice

    Autonomous Control of the Large-Angle Spacecraft Maneuvers in a Non-Cooperative Mission

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    Aiming at the large-angle maneuver control problem of tracking spacecraft attitude in non-cooperative target rendezvous and proximity tasks, under the condition that the target spacecraft attitude information is unknown and the actuator output has physical limitations, a limited-time autonomous control method is proposed. First, an end-to-end pose estimation network is designed based on adaptive dual-channel feature extraction and dual attention. The information around the target is obtained through the adaptive dual-channel feature extraction module. The addition of spatial attention and channel attention allows the network to learn the target’s characteristics more accurately. Secondly, based on the improved adaptive update law, a finite-time saturation controller is designed using the hyperbolic tangent function and the auxiliary system. The hyperbolic tangent function can strictly ensure that the control torque of the control system is bounded. Finally, the simulation results show that the proposed autonomous control method can accurately estimate the attitude of the non-cooperative target spacecraft and can maneuver to the target attitude within 20 s under the condition that the actuator’s output is physically limited

    Effects of Nb2O5 additive on the piezoelectric and dielectric properties of PHT-PMN ternary ceramics near the morphotropic phase boundary

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    Recently, a new family of piezoelectric perovskite materials, PbHfO 3-PbTiO3-Pb(Mg1/3Nb2/3)O 3 (PHT-PMN) ternary system was developed, possessing good piezoelectric properties and high Curie temperature near the morphotropic phase boundary (MPB). Nb2O5, as a donor dopant in the perovskite piezoelectric systems has been used to improve the dielectric and piezoelectric properties. In this work, the effect of Nb2O5 addition in the PHT-PMN ternary system was reported. It was found that Nb doping led to the change of phase structure for the PHT-PMN system. With the addition of Nb 2O5 content, the ferroelectric polarization was reduced, while the electric-field-induced strain and hysteresis were enhanced significantly. In particular, the 0.2 wt% Nb2O5-doped PHT-PMN exhibited the optimum piezoelectric and electromechanical properties, with d33 and kp being on the order of 670 pC N -1 and of 71%, respectively. 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

    Shock Wave Attenuation Characteristics of Aluminum Foam Sandwich Panels Subjected to Blast Loading

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    Comparative experiments were conducted with two different structures to study the mechanism of aluminum foam sandwich attenuating blast shock wave. The sandwich structure is composed of “steel–aluminum foam–steel,” and the mild steel structure is composed of “steel–steel.” In the experiment, the polyvinylidene fluoride transducers were used to directly test the load of stress wave between different interfaces of sandwich and mild steel structures. The strain of back sheet was simultaneously measured using high-precision strain gauge. The accuracy of the test results was verified by Henrych’s formula. Experimental results show that the wave attenuation rate on the mild steel structure is only 11.3%, whereas the wave attenuation rate on the sandwich structure can exceed 90%. The interface effect is clearly a more crucial factor in the wave attenuation. The peak value of back sheet strain in the mild steel structure is much higher than the sandwich structure. The apparent overall “X” crushing band is produced in the aluminum foam core, and scanning electron microscope (SEM) observation clearly shows the collapse of the cell wall. Experiments on the sandwich structure with different aluminum foam densities indicate that increasing the relative density results in increased attenuation capability of the aluminum foam and decreased attenuation capability of the sandwich structure. Experiments on the sandwich structure with different aluminum foam thickness indicate that increasing the thickness results in increased attenuation capability of the aluminum foam and the sandwich structure

    Water-Depth-Based Prediction Formula for the Blasting Vibration Velocity of Lighthouse Caused by Underwater Drilling Blasting

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    Lighthouses are the most important hydraulic structures that should be protected during underwater drilling blasting. Thus, the effect of blasting vibration on lighthouse should be studied. On the basis of the dimensional analysis, we deduced a revised formula for water depth based on Sodev’s empirical formula and established the linear fitting model. During the underwater reef project in the main channel of Shipu Harbor in the Ningbo–Zhoushan Port, the blasting vibration data of the lighthouse near the underwater blasting area were monitored. The undetermined coefficient, resolvable coefficient, and F value of the two formulas were then obtained. The comparison of the data obtained from the two formulas showed that they can effectively predict the blasting vibration on the lighthouse. The correction formula that considers water depth can obviously reduce prediction errors and accurately predict blasting vibration

    Investigation of the Propagation Characteristics of Underwater Shock Waves in Underwater Drilling Blasting

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    During the first-stage project of the main channel of Ningbo-Zhoushan Port’s Shipu Harbor, underwater shock waves were monitored. By analyzing a typical measured pressure time history curve, the characteristics of underwater shock waves in an engineering context were obtained. We obtained a traditional exponential attenuation formula for underwater shock waves based on the measured data, simplified the model of underwater drilling blasting based on engineering practice, deduced a revised formula for underwater shock wave peak overpressure on the basis of dimensional analysis, established a linear fitting model, and obtained the undetermined coefficients of the revised formula using a linear regression analysis. In addition, the accuracies of the two formulas used to predict underwater shock wave peak overpressure and the significance order of influence and influence mechanism of factors included in the revised formula on the underwater shock wave peak overpressure were discussed

    Interval grey number of energy consumption helps task offloading in the mobile environment

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    The mobile device has been widely used in many areas. Task offloading is always used to overcome the limitation of processing ability and energy-supply of the mobile devices in the mobile cloud environment. Most researches suppose we know the detail of task (number of instructions) of every sub-task. But most of time, to get the detail of a task is very difficult. This paper uses the grey number to express that uncertain information and propose method to evaluate the performance of offloading tasks. Simulations show that our method selects the solution with the lowest energy consumption

    Infrared Small Target Detection Based on Multiscale Kurtosis Map Fusion and Optical Flow Method

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    The uncertainty of target sizes and the complexity of backgrounds are the main reasons for the poor detection performance of small infrared targets. Focusing on this issue, this paper presents a robust and accurate algorithm that combines multiscale kurtosis map fusion and the optical flow method for the detection of small infrared targets in complex natural scenes. The paper has made three main contributions: First, it proposes a structure for infrared small target detection technology based on multiscale kurtosis maps and optical flow fields, which can well represent the shape, size and motion information of the target and is advantageous to the enhancement of the target and the suppression of the background. Second, a strategy of multi-scale kurtosis map fusion is presented to match the shape and the size of the small target, which can effectively enhance small targets with different sizes as well as suppress the highlighted noise points and the residual background edges. During the fusion process, a novel weighting mechanism is proposed to fuse different scale kurtosis maps, by means of which the scale that matches the true target is effectively enhanced. Third, an improved optical flow method is utilized to further suppress the nontarget residual clutter that cannot be completely removed by multiscale kurtosis map fusion. By means of the scale confidence parameter obtained during the multiscale kurtosis map fusion step, the optical flow method can select the optimal neighborhood that matches best to the target size and shape, which can effectively improve the integrity of the detection target and the ability to suppress residual clutter. As a result, the proposed method achieves a superior performance. Experimental results on eleven typical complex infrared natural scenes show that, compared with seven state-of-the-art methods, the presented method outperforms in terms of subjective visual effect, as well as some main objective evaluation indicators such as BSF, SCRG and ROC, etc

    Distribution Analysis of Salvianolic Acids in Myocardial Ischemic Pig Tissues by Automated Liquid Extraction Surface Analysis Coupled with Tandem Mass Spectrometry

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    The distribution of active compounds of traditional Chinese medicine Salvia miltiorrhiza Bunge (Chinese name: Danshen) in vivo was determined by establishing a liquid extraction surface analysis coupled with the tandem mass spectrometry (LESA-MS/MS) method. Stability analysis and distribution analysis were designed in the present study using normal animals or a myocardial ischemia model. The model assessment was performed four weeks after surgery, and then three groups were created: a normal-dose group, a model-blank group, and a model-dose group. Meanwhile, Danshen decoction administration began in dose groups and lasted for four weeks. In stability analysis, four salvianolic acids—Danshensu (DSS), caffeic acid (CAA), rosmarinic acid (RA), and salvianolic acid A (SAA)—in kidney tissues from the normal-dose group were detected by LESA-MS/MS under four conditions, and then distribution analysis was conducted in different tissues using the same method. Ejection fraction (EF) and fractional shortening (FS) in animals from two model groups decreased significantly four weeks after surgery (P  0.05). Distribution analysis showed the signal intensities of DSS in the liver and kidney and SAA in the heart were higher in the model-dose group than in the normal-dose group (P < 0.05 or P < 0.01). Signal intensities of RA in the liver and kidney, and SAA in the liver were lower in the model-dose group compared with the normal-dose group (P < 0.05 or P < 0.01). In conclusion, Danshen decoction has the effect of improving the ischemic condition in a chronic myocardial ischemia model, and the content of two active compounds increased in the targets. These findings contribute to an understanding of the therapeutic role of Danshen in cardiovascular disease
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