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Aiming at the issue of complex 3D shape analysis and recognition, this paper presented a novel 3D graph convolu- tion classification method. It established a joint graph convolution learning mechanism of local geometry and global structure to provide both geometrical features and global context features, which effectively improved the robustness and stability of 3D data learning. Firstly, it constructed the local graph in spatial domain by farthest point sampling and K-nearest neighbor method, and designed a dynamic spectral graph convolution operator to extract local geometric features effectively. Meanwhile, it con- structed the global feature graph based on random sampling in the feature domain, and obtained the global structure context by spectral graph convolution. Furthermore, it established a weighted graph convolution network with an attention mechanism to achieve adaptive feature fusion. Finally, under the optimization of objective function, it improved the performance of feature learning effectively. Experimental results show that the proposed joint network learning mechanism, which combined local geo- metric features with global structure features, enhances the representation ability and discrimination of deep features, and ob- tains better recognition and classification performance compared with advanced methods. This method can be used for large- scale point clouds recognition, 3D shape reconstruction and data compression. It has important research significance and broad application prospects in robot, product digital analysis, intelligent navigation, virtual reality and other fields. [ABSTRACT FROM AUTHOR]

BACKGROUND: Exercise therapy for adolescent idiopathic scoliosis has been recognized by The International Scientific Society on Scoliosis Orthopaedic and Rehabilitation Treatment, but there are fewer clinical studies on specific physiotherapy combined with exercise therapy for specific subtypes of adolescent idiopathic scoliosis. OBJECTIVE: To analyze the clinical effect of instrument-assisted soft tissue mobilization combined with physiotherapy scoliosis specific exercises on adolescent patients with idiopathic scoliosis type RigoA. METHODS: Eighteen adolescent idiopathic scoliosis RigoA patients admitted to The Fifth Hospital of Harbin City between December 2020 and December 2021 were selected, including 6 males and 12 females, at the age of 10-16 years. The patients were randomly divided into trial group (n=10) and control group (n=8). The trial group underwent Instrument-Assisted Soft Tissue Mobilization combined with Physiotherapy Scoliosis Specific Exercises and the control group only received Instrument Assisted Soft Tissue Mobilization. The frequency of treatment was once a week. RESULTS AND CONCLUSION: (1) After 24 weeks of treatment, the Cobb angle and thoracic curvature of the trial group were lower than those before treatment (P < 0.05), while the Cobb angle and thoracic curvature of the control group had no significant changes compared with those before treatment (P > 0.05). The Cobb angle and thoracic curvature were lower in the trial group than those of the control group (P < 0.05). (2) After 24 weeks of treatment, the axial trunk rotation angle of the trial group was lower than that before treatment (P < 0.05). There was no significant change in the axial trunk rotation angle in the control group compared with that before treatment (P > 0.05). The axial trunk rotation angle of the trial group was lower than that of the control group (P < 0.05). (3) The visual analog scale scores of the first treatment and 10 and 24 weeks after treatment in both groups were lower than those before treatment (P < 0.05). The visual analog scale score of the trial group after 24 weeks of treatment was lower than that of the control group (P < 0.05). (4) After 24 weeks of treatment, the vital capacity of the trial group was higher than that before treatment (P < 0.05). There was no significant change in the vital capacity of the control group compared with that before treatment (P > 0.05). The vital capacity of the trial group was higher than that of the control group (P < 0.05). (5) These results indicate that the combination of Instrument-Assisted Soft Tissue Mobilization and Physiotherapy Scoliosis Specific Exercises proved to be effective in reducing the axial trunk rotation angle of scoliosis, reducing back pain and increasing vital capacity, and controlling the development of the scoliosis curve in adolescent idiopathic scoliosis RigoA patients. [ABSTRACT FROM AUTHOR]

BACKGROUND: With the development of modern industry, modern national defense and modern medical rehabilitation industry, bionic design and manufacturing technology is booming. This technology often takes various organisms and their tissues as research objects, imitating their geometric shapes, mechanical properties and other indicators, and then achieves reverse design and manufacture of various synthetic products, in which the effective bionics of geometric shapes, especially surface modeling technology, is a key part of it. OBJECTIVE: Taking the human knee joint as an example, this paper discussed the practical application technology of surface modeling, and established a digital model of the geometric anatomy of the human knee joint. It provided support for the research on the biomechanical properties of the knee joint, and at the same time provided an effective teaching and research model for the complex surface modeling of the bionic mechanism. METHODS: Using knee CT scan images and magnetic resonance imaging images, the point cloud data and approximation curves of bone tissue and soft tissue contours were obtained through medical image processing technology, respectively, and the knee joint entity models of bone tissue and soft tissue were reconstructed respectively. Finally, based on the 3D image registration technology, each soft tissue group was assembled on the bone tissue entity model to form the overall knee joint 3D model. RESULTS AND CONCLUSION: Through 3D medical imaging technology, a digital anatomical digital model of knee joint with complex geometric surfaces including various bone tissues and ligaments, meniscus, tendons and other major soft tissues was constructed. [ABSTRACT FROM AUTHOR]

BACKGROUND: Research on movement process, data, and mechanism of the knee joint is helpful to design and modify a knee joint prosthesis, and improve the knee joint movement function according to its movement characteristics and biomechanical characteristics, so as to avoid sports injuries, improve sports performance and prolong sports life. The movement data of the knee joint are the basis for studying its mechanical properties. OBJECTIVE: According to the three-dimensional geometric model of the knee joint, to determine the movement data of the tibiofemoral joint and the patellofemoral joint at different flexion angles, thereby providing a new approach and reference for the kinematic analysis of complex spatial mechanisms such as robots and for the mechanical analysis and design of artificial prostheses. METHODS: First, the three-dimensional point cloud of the knee joint at 0°-120° static knee flexion was captured using computed tomography. Secondly, the combination of three-dimensional image registration and coordinate transformation was proposed to accurately analyze the relative motion of the knee joint. Three-dimensional images of the knee joint (including the femur, tibia, patella) in different flexion positions and their coordinates were presented in the same coordinate system. The orthogonal coordinate system of each bone tissue of the knee joint was then established. The movement of the knee joint was studied based on coordinate transformation using the Z-Y-X Euler angle method around the motion coordinate system. RESULTS AND CONCLUSION: (1)The motion data of the tibiofemoral and patellofemoral joints with 0°-120° of knee flexion were obtained in the five degrees of freedom, which offers a support for studying the mechanical properties of the knee joint and prosthetic design. This method could be used for the motion analysis of kinematics pairs under complex kinematics in mechanism. (2)To conclude, this method is proposed based on multi-static discrete medical images for kinematic measurement and analysis in human body. It can be conducted based on existing computed tomography scanning equipment and existing software, which has low cost and is easily understood. Moreover, this method is characterized by high measurement accuracy and the accuracy error is less than 1 mm. [ABSTRACT FROM AUTHOR]

At present, most emergence data is multi-source heterogeneous spatial data, and exists some problems such as uneven data quality, inconsistent semantic model, unclear mathematical foundation and resolution. After studying various spatial data structures, this paper proposes a proper general metadata model for high-level structure and pattern matching, and establishes a spatial data concept enhancement paradigm to perform research on singleobjective feature measurement, relation detection between objects, group object importance ranking, group object cluster analysis, group object structure relationship identification. And the disaster information is extracted and modeled using ontology to form the data enhancement agent. The experiment results show that this agent can mine disaster hidden information, improve early warning efficiency, and enhance the concept of visual spatial data. [ABSTRACT FROM AUTHOR]

Objective: Earthquake occurred frequently in China. More knowledge needs to be discovered to take timely emergency actions to mitigate earthquake damage. Thus the construction method of knowledge discovery model for earthquake emergency is one of the core research issues in earthquake emergency field. It is worth studying how to realize knowledge discovery for earthquake emergency from abundant and complicated data under less support of prior knowledge. Methods: We put forward a kind of text big data based knowledge discovery model for earthquake emergency. First, text data associated with earthquake emergency is collected, including both academic document data (CNKI(China national knowledge infrastructure) data) sets and social media data sets(Weibo data). Then CiteSpace tool and formal concept analysis method are utilized to extract the high-frequency keywords and their linkages, the linkages’ frequency between keywords as linkage strength, a complex network of earthquake emergency knowledge is established for community classification. After community dividing, several big communities can be divided from the former established complex network. Results: From big communities’ further analysis : (1) in seismic resistance design domain, the discovered knowledge has high coherence with expert knowledge; (2) in earthquake rescue domain, the discovered knowledge shows that China Earthquake Administration have responsibility to afford emergency information services as well as public opinion guiding; (3)in geological hazards domain, the discovered knowledge founds the vegetation restoration in geological disaster area should be paid more attention; (4) the knowledge discovered from academic document data and social media data can be complementary. Conclusions: The experiment result shows that the model can find relevant knowledge, especially those experts rarely concern. [ABSTRACT FROM AUTHOR]

Based on the operational mechanism of ship-based laser deflection decoy jamming system and the impulsive factor damage standard for underwater explosion, a calculational method of safe distance for ship-based laser deflection decoy jamming system is investigated. The safe distance of ship-based laser deflection decoy jamming system from different laser guidance weapons is calculated based on the proposed calculation method, and the results are analyzed. The effects of flight velocity, water entry angle and explosive loading of laser guided weapons on the safe distance are discussed. The calculated results show that the flight velocity and explosive loading of laser guidance weapons are the main factors of affecting the safe distance. The safe distance increases with explosive loading of laser guidance weapons, and changes dramatically with water entry angle at increased flight velocity. The results give support to the selection of safe distance of ship-based laser deflection decoy jamming system. [ABSTRACT FROM AUTHOR]

Benzenes of wide sources can cause serious air pollution. In this study, a novel enrichment sampling device based on multi-capillary column was developed and coupled to portable photoionization time-of-flight mass spectrometer (PI-TOF-MS) to highly and sensitively detect benzenes in ambient air. The enrichment sampling device was composed of seven identical HP-PLOT Q capillary columns (0.10 m×0.53 mm×40 μm) coated with polystyrene-divinylbenzene, which could achieve efficient adsorption of benzenes at room temperature. The homebuilt portable PI-TOF-MS has a volume of (0.47×0.35×0.38) m³, a weight of 35 kg, and a resolution of better than 1 000 (full width at half-maximum, FWHM) at m/z 92. Benzene, toluene and p-xylene gas diluted by nitrogen were used to optimize the operating parameters of the whole system. The optimal sampling flow rate was selected as 500 mL/min, the enrichment time was 4 min, the thermal desorption temperature was 160 ℃, and the analytical time for single sample was less than 10 min. Compared with direct sampling, the signal intensities of benzene, toluene and p-xylene were enhanced by 130, 220 and 255 folds under the optimal conditions, respectively. The linearity, limit of quantitation (LOQ) and stability of the system were evaluated. As a result, the linear concentration range of 6.96-1 741.05 μg/m3 for benzene, 8.21-2 053.55 μg/m³ for toluene, and 9.46-2 366.05 μg/m³ for p-xylene were obtained with the correlation coefficients (R²) of 0.993 8, 0.999 7 and 0.999 1, respectively. The limits of quantification (LOQs, S/N=10) were 0.78, 0.63 and 0.76 μg/m³, respectively. The relative standard deviations of the signal strengths for the three compounds were less than 6% during seven analytical cycles. Finally, the developed multi-capillary column enrichment portable PI-TOF-MS was used for comparative analysis of indoor and outdoor air in the laboratory. As a consequence, toluene and p-xylene were detected in both indoor and outdoor air of the laboratory. The indoor concentrations of the two compounds were 2.6 and 23.3 μg/m³, respectively, which were much lower than the legal limit concentrations. Due to better ventilation, the outdoor concentrations of toluene and p-xylene were 0.5 and 16.4 μg/m³, respectively. In addition, ethanol, methanthiol, acetone, etc. were also detected in indoor air of the laboratory, which may come from human exhalations or chemical reagent emissions. The results showed that the instrument can meet the requirements of trace benzenes detection in ambient air, and has broad application prospects in the field of on-site environmental analysis. [ABSTRACT FROM AUTHOR]

Lifting platform for orchards plays a significant role in the fruit industry, because it successfully solves many difficult problems of picking fruit and trimming branches. However, there are some uncontrollable problems such as leveling instability, poor operational capacity in current machines. So it is necessary to design better leveling system to improve their working efficiency and stability. Domestic and foreign scholars have done a lot of researches on the leveling system for high-altitude lifting platforms, which provide important academic reference for the design and improvement of the leveling system for orchards lifting platform. There are higher leveling requirements because of poor terrain in orchards. United States, Australia and Japan are the earlier countries to produce lifting platform for orchards and their devices have achieved the automatic leveling. They are yet too expensive for Chinese farmers to afford. In China, it was not until 1980s that the lifting platform for orchards was made. Some types of the lifting platforms made in China realized mechanical leveling, but their leveling accuracy and working efficiency were lower. To this end an auto leveling control system was designed on the basis of the related information at home and abroad. Such a leveling control system consisted of lifting platform, leveling mechanism, hydraulic system and control system. By analyzing forces and movement of the leveling mechanism of the leveling control system, the dynamic mathematical model for the control system was set up. As we all know, the fuzzy control can decrease the overshoot, and PID (proportion, integral, derivative) control can increase the response speed, and Kalman filter can reduce signal interference. So the fuzzy PID control system with Kalman filter was designed. According to the information collected by inclinometer, the control system makes a decision, and then controls electromagnetic valve to drive the leveling cylinder to extend or retract, which can change the motion of the work platform and keep it level. The results of simulation showed that the performance of fuzzy PID control system was better than that of traditional PID. Firstly its rise time was 0.09 s, it’s peak time was 0.12 s, its regulation time was 0.41 s, and they were respectively shortened by 43.75%, 47.82%, and 48.10%, respectively, which indicated the initial and overall speed of fuzzy PID control system were better. Secondly the maximum overshoot was 17%, which was reduced by 52.78% of traditional PID’s, so fuzzy PID control system realized a good stabilization. Moreover in combination with Kalman filter, the leveling precision of fuzzy PID control system was improved greatly. Its steady state error was about 0.051° and was reduced by 44.57% of PID’s. The experiments were done in different slopes (5.1°, 10.5°, 14.5° and 18.8°) and different loads (0, 50, 100, and 150 kg). The results showed that the performance of automatic leveling system was better compared with the original leveling control system. The response time of automatic leveling control system was shorter and was about 0.078 s. When the platform wasn’t lifted, under the maximum load and the slope of 18.8°, the maximum automatic leveling error was 1.08°, the automatic leveling precision was increased by 1.69°. In the process of the platform lifted, the maximum automatic leveling error was 1.74º, and the automatic leveling precision was increased by 1.91°. In addition, there were some occasional phenomena such as leveling inaccurately and running slowly in the process of experiments. There were following main 3 reasons: 1) Irregular terrain disturbed the signals collected by angle sensors; 2) The workbench deviated from the set position because of hinge clearances; 3) With the action of motion inertia, the workbench swung back and forth when rising or falling too fast. So the following works will be carried out, including modifying the mechanical structure of lifting platform, and researching control algorithm and mathematical model of the control system to improve control accuracy and leveling efficiency. In conclusion, the automatic leveling control system can meet the design requirements and effectively improve leveling degree and work efficiency, and is well suitable for orchards. [ABSTRACT FROM AUTHOR]

ObjectiveTo investigate the incidence of postoperative complications in laparoscopic versus open common hepatic duct-jejunal Roux-en-Y anastomosis. MethodsThe databases of PubMed, Web of Science, CNKI, VIP, and Wanfang Data were searched for related studies on postoperative complications in laparoscopic or open common hepatic duct-jejunal Roux-en-Y anastomosis published up to May 20, 2016. Two reviewers performed literature screening according to inclusion and exclusion criteria, data extraction, and quality assessment independently. STATA12.0 software was used for the meta-analysis. ResultsA total of 9 studies with 548 patients were enrolled. Among these patients, 261 underwent laparoscopic surgery and 287 underwent open surgery. The results of the meta-analysis showed that compared with the open surgery group, the laparoscopic surgery group had lower incidence rates of total complications (OR=0.40, 95% CI： 0.24-0.68, P=0.001), incision infection (OR=0.20, 95% CI： 0.08-0.53, P=0.001), and adhesive ileus (OR=0.25, 95% CI： 0.06-0.99, P=0.049). However, there was no significant difference in the incidence of bile leakage between the two groups (P＞0.05). ConclusionCompared with open surgery, laparoscopic common hepatic duct-jejunal Roux-en-Y anastomosis has a lower incidence of total postoperative complications, and therefore, it is a safe and feasible surgical procedure. [ABSTRACT FROM AUTHOR]

Objective: To study and compare the clinical effects of posterior lumbar interbody fusion(PLIF) and transforaminal lumbar interbody fusion(TLIF) on the treatment of degenerative lumbar spondylolisthesis(DLS) combined with lumbar spinal stenosis(LSS) for elderly patients. Methods: 40 elderly patients with DLS and LSS who were admitted in our hospital from December 2011 to December 2014 were recruited and according to the different operation methods, the patients were divided into the PLIF group and the TLIF group. Then the operation time, intraoperative blood loss, postoperative drainage volume, postoperative time of staying in bed, visual analogue pain score(VAS), Oswestry dysfunction index(ODI) and complications of the two groups were observed and compared.Results: The intraoperative blood loss, postoperative drainage volume and time of staying in bed of TLIF group were better than those of the PLIF group, and the differences were statistically significant(P<0.05); there was no statistically significant difference about the operation time between the two groups(P>0.05). The VAS and ODI scores half a year after the operation in the two groups were significantly better than before, and the differences were statistically significant(P<0.05); There was no statistically significant difference about the VAS and ODI scores between the two groups(P>0.05). The occurrence rate of complications of TLIF group was obviously lower than that of the PLIF group, and the differences were statistically significant(P<0.05). Conclusion: TLIF demonstrates has better effect on the treatment of DLS and LSS for elderly patients with less postoperative complications. [ABSTRACT FROM AUTHOR]

Objective: To observe the clinical effects of single balloon bilateral alternating on expansion after kyphoplasty on the treatment of osteoporotic vertebral compression fractures for elderly patients. Methods: 60 elderly patients with senile osteoporosis osteoporotic vertebral compression fractures who were treated in our hospital from July 2014 to May 2015 were selected and according to the degrees of vertebral collapse, the patients were divided into the severe fracture group and the slight fracture group, with 30 cases in each group. The patients in the two groups were treated with the double balloon dilatation of the single balloon, and the effect of the treatment and the changes of the vertebral body were observed and compared. Results: Compared with the slight fracture group, the operation time in the severe fracture group was longer, the bone cement was less and the rates of vertebral height restoration and the middle part of the vertebral body height recovery and the Cobb angle correction were higher (P<0.05). After the operation, the VAS score of the two groups were better than before (P<0.05), while there was no statistically significant difference between the two groups (P>0.05). Compared with before, the anterior height of vertebral body, vertebral middle height and Cobb angle of patients in the two groups improved after the operation (P<0.05), and the anterior height of vertebral body and the middle part of the vertebral body height in the slight fracture group were better than those of the severe fracture group (P<0.05). There was no statistically significant difference about the Cobb angle between the two groups after the operation (P>0.05). Conclusion: The bilateral alternating expansion of the single spherical sac has better clinical effect on the treatment of senile osteoporotic vertebral compression fractures for elderly patients, which can obviously correct the vertebral collapse and Cobb angle. [ABSTRACT FROM AUTHOR]

In order to explore the effect of extremely low frequency high-voltage pulsed electric field on the aged cotton seed vigor, high voltage pulse power supply and arc electrode were used to treat aged cotton seeds with different voltages and frequencies. The treatment time was 40 s. The experiment environment temperature was set as 25 °C, the relative humidity was set as 30%, and the temperature and humidity were remained relatively stable during the experiment. The effect of high voltage and extremely low frequency on germination ability of aged cotton seeds was studied. The voltage of vertically downward electric field was 12-20 kV, the pulse frequency was 5-15 Hz, the electrode was arc, and the distance between electrode plates was 50 mm. The point of 16 kV and 10 Hz was selected as die center point, and the orthogonal test was designed by Design-Expert software. The CK stood for the aged cotton seeds that had not been treated by electric field. The aged cotton seeds treated by electric field were taken into the sealed bag in time, and all the seeds were germinated within 4 h after treatment. The aged cotton seeds in sealed bag were put separately into the HgCl2 solution with mass fraction of 0.2% for sterilization before seeds germination, and then 50 seeds were selected randomly from each seed sterilization group. Finally, the selected seeds were cleaned and put on the gennination bed with sand bed metliod. The seed gennination experiments were carried out at the National Key Laboratory of Crop Biology, Shandong Agricultural University, which were in accordance with the national standard: 25 constant temperature, continuous light, and relative humidity of 100%. Four boxes of seeds were treated under each electric field for 40 s, which were 4 repetitions, and then the average of each index was calculated. During the cotton seeds gennination. the moldy cotton seeds should be removed timely, in order not to affect other seeds growth. According to the response surface analysis of the pulsed electric field and the arc electrode to the dynamic index of the aged cotton seed, and the single factor analysis of the pulsed electric field and the arc electrode to die cotton vigor index, the effect of increasing the voltage on the aged cotton seed vigor index was similar. At different voltages, the influence of increasing frequency on the cotton seed vigor index was similar. On the whole, the cotton seed vigor index after arc electrode electric field treatment showed a tendency of rising firstly and then falling with the increasing of voltage and frequency. And the influence of pulse frequency on cotton vigor index was obvious. Using the Design-Expert software, die pulse voltage and frequency were optimized, and the optimal condition was that the pulse voltage was 16.25 kV and the pulse frequency was 10.90 Hz. Under the optimal condition, the gennination potential was increased by 44.2%, the germination rate was increased by 56.S%, the gennination index was increased by 64.3%, and the vigor index was increased by 81.8%, and the indices were all significantly different (P<0.01) from that of the CK. [ABSTRACT FROM AUTHOR]

In order to explore the effect of the frequency of the pulsed electric field on the aged cotton seed vigor, high voltage pulse power supply and arc electrode were used to process aged cotton seeds with different frequency of 1, 5, 10, 20 and 50 Hz at the voltage of 16 and 20 kV, and the treatment time was 40 s. The results showed that the change trends of all indices were consistent for pulsed electric field with different frequency. When the frequency of the electric field increased, the effects increased and reached the maximum at 10 Hz. It could be seen that the electric field frequency had a threshold in this test condition. After 10 Hz, as the electric field frequency increased, the effects began to decrease. Compared with the CK, the germination potential showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 5, 20 and 50 Hz, but no significant difference at 1 Hz. The germination rate showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 5, 20 and 50 Hz, but no significant difference at 1 Hz. The germination index showed a very significant difference (P<0.01) at 5, 10 and 20 Hz, and a significant difference (P<0.05) at 50 Hz, but no significant difference at 1 Hz. The vigor index showed a very significant difference (P<0.01) at 5, 10, 20 and 50 Hz, but no significant difference at 1 Hz. In conclusion, when the voltage was 16 kV, the treatment effect was better at 10 Hz. The 4 indices of cotton seeds with the 10 Hz treatment were increased by 39%, 54%, 57% and 81% respectively in comparison with that of the CK. In comparison with that of the CK at the voltage of 20 kV, the germination potential showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 5 Hz, but no significant difference at 1, 20 and 50 Hz. The germination rate showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 1, 5 and 20 Hz, but no significant difference at 50 Hz compared with the CK. The germination index showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 1, 5, 20 and 50 Hz. The vigor index showed a very significant difference (P<0.01) at 10 Hz, and a significant difference (P<0.05) at 1, 5, 20 and 50 Hz. In conclusion, when the voltage was 20 kV, the treatment effect was better at 10 Hz. The 4 indices of cotton seeds with the 10 Hz treatment were increased by 28%, 43%, 38% and 62% respectively in comparison with that of the CK. The results showed that when the frequency was 10 Hz, the germination potential, germination rate, germination index and vigor index were significantly improved, and had very significant difference (P<0.01). The treatment condition of 16 kV was better than 20 kV. The results indicated that the effect of electric field frequency on seed vigor index existed, and the influence trend of each index was consistent. It means that there is an optimal frequency range when the electric field strength and processing time are determined. It can increase seed vigor to the maximum. [ABSTRACT FROM AUTHOR]

In order to study the degradation law of steel mechanical properties and seismic performance of frame joints with corrosion degree increased in the acidic atmospheric environment, the one directional tensile tests of 24 standard steel material specimens were performed and 12 beam-column joint specimens in different corrosion levels were tested under cyclic loading. Based on material test data, the linear regression relationship between the yield strength, ultimate strength, elastic modulus, elongation and weightlessness rate was established, the influences of different corrosion rates and loading systems on loading-displacement curve, skeleton curve, strength and stiffness degradation, deformability, hysteretic energy dissipation of steel frame joint were analyzed. The degradation laws of load carrying capacity, strength, stiffness and energy dissipation capacity of the corroded steel frame joint with the corrosion degree increased were established. The results show that corrosion has a significant impact on the damage pattern of steel frame joint. With the increase of corrosion degree, the energy dissipation of the specimens decreases gradually, the load carrying capacity falls sharply in the late loading stage and the brittle fracture occurs more obvious. With the increase of displacement amplitude and cycle number, the plastic deformation of steel frame joint is accumulated gradually, the stiffness and strength degradation is obvious. Under the same corrosion degree, the energy dissipation capacity of specimen with variable amplitude loading is the biggest of all, followed by the mixed loading, and the constant amplitude the minimum. The results can provide experimental support for the seismic fragility study of existing steel frame structure. [ABSTRACT FROM AUTHOR]

Objective: To compare the clinical curative effect of total hip arthroplasty (THA) and bipolar hemiarthroplasty (BHA) on the treatment of senile femoral neck fracture for elderly patients. Methods: 90 elderly patients with femoral neck fracture who were treated in our hospital from July 2013 to March 2015 were selected, and according to the different treatment methods, the patients were divided into the total hip arthroplasty group (THA) and the bipolar hemiarthroplasty group (BHA), with 45 cases in each group. Then the operation time, the intraoperative blood loss, the hospitalization, the incidence of postoperative complications and the clinical effects in the two groups were observed and compared. Results: There was no statistically significant difference about the operation time, the intraoperative blood loss and the hospitalization of the patients in the two groups (P>0.05); The incidence of postoperative complications in the THA group was lower than that of the BHA group (P<0.05); There was no statistically significant difference about the clinical effects in the two groups after the treatment for one year (P>0.05); The clinical effects in the THA group after the treatment for two and three years were significantly higher than those of BHA group, and the differences were statistically significant (P<0.05). Conclusion: THA and BHA have a good clinical efficacy on the treatment of senile femoral neck fracture for elderly patients, and THA is better for a long-termcurative effect and lower postoperative complications. [ABSTRACT FROM AUTHOR]