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The fuel efficiency of the engine is only 15%-35% while the tractor is working in the field, and the exhaust energy accounts for 38%-45% of the energy released by the fuel. The recovery and reuse of exhaust heat energy could help improve fuel efficiency and reduce emissions. Studies have shown that the exhaust waste heat energy based on the Organic Rankine Cycle (ORC) is the highest. The evaporator is a key component of the ORC system, analyzing its thermal performance under limited space conditions of the tractor could provide a theoretical basis for the optimal design of evaporator parameters, thereby effectively improving the utilization of exhaust heat. This study according to the actual size of the tractor, a plate-fin evaporator was trial-produced to recover diesel exhaust waste heat. A numerical model of convective heat transfer between evaporator exhaust and working fluid based on moving boundary method was established and was verified the validity by combining with bench test data, the thermal performance of the evaporator under full operating conditions of the diesel engine was quantitatively analyzed; meanwhile in order to improve the heat transfer and scope of application of the evaporator, CFD simulation and BP neural network methods were used to further analyze the heat transfer characteristics of the evaporator under off-design conditions, the structure and working fluid parameters were optimized. The results showed that: 1) the evaporator had better thermal performance under medium and high speed load conditions, and the heat transfer reached a maximum of 69.89 kW under 4 000 r/min full load conditions, and the heat transfer of the evaporator would be unstable under medium and low speed load conditions due to the lower exhaust heat capacity flow rate, heat transfer coefficient, and a larger working fluid mass flow rate, resulting in the flow was difficult to ensure that the working fluid was transformed into superheated steam, so that the heat transfer in the two-phase zone and the superheat zone was zero within the evaporator. 2) in order to improve the distribution and turbulence of the fluid in the flow channel, increasing the pipe chamfer and adopting the corrugated fin shape to promote forced heat exchange, the CFD simulation showed the entire high-temperature area moved forward to the inlet of the nozzle to make the flow channel utilization rate higher and heat transfer more. With the optimized structure of the evaporator, the working fluid had a higher degree of overheating under the condition of the same overall size, the maximum heat transfer increased by 5.2%, the heat transfer area increased by 0.19 m², and the volume only increased by 0.002 m³ . 3) combined with the BP neural network algorithm, the evaporator flow channel length, working fluid flow and inlet temperature were optimized parameters, and the thermal performance of the evaporator under off-design working conditions was further analyzed, and the parameter range under the medium and low speed load conditions is determined. Thus, the selection range of the working fluid flow rate at different speeds was proposed, which effectively improving the thermal performance of the evaporator under low-to-medium speed load conditions, and providing a reference for the selection of the transmission ratio of the booster pump and the output speed of the diesel engine and the selection of the transmission device. For example, when 1 500 r/min was under a medium and high load, the flow rate could be changed from 0.03 kg/s to 0.08 kg/s and the maximum heat transfer up to 19.46 kW; at the same time, the transmission ratio could be set to 0.78-1.88 at 1 500 r/min. The results of the study are of great significance and present the fluid flow and heat transfer characteristics of the evaporator, which provide a reference for the actual use of the evaporator in tractors and matching with diesel engine operating conditions. [ABSTRACT FROM AUTHOR]

In order to clarify the fruiting law of the sand whip under different ecological environmental conditions, this article conducted field observations on the seed setting of 137 populations of sand whip, and found that the seed setting of sand whip seeds can be divided into seedless, full seed and insufficient seed. Three types; on this basis, the paper uses cluster analysis, Kriskal-Wallis test and Canonical Correspondence Analysis (CCA) methods to explore the correlation between the seed setting of the sand whip population and 22 geographic and climatic factors. The results showed that: (1) The 137 populations of Rhizoma sylvestris were clustered into 3 groups according to different geographical and climatic factors; (2) The Kruskal-Wallis test showed that the seed setting conditions of the three groups of Rhizoma sylvestris were not significantly different (P=0.269). There is no direct correlation between the seed setting and the geographical and climatic factors of the whip populations; (3) Canonical Correspondence Analysis (CCA) shows that the difference in seed setting between the whip populations is not significant (P>0.05), but the geographical and climatic factors are related to the seeds. There is a significant correlation between fullness and seed-free characteristics. Among them, altitude and rainfall factors (bio12-bin19) are positively correlated with seed fullness, while latitude and longitude and temperature factors (bio4, bio7) are negatively correlated with seed fullness, and no-seed characteristics are only It is positively correlated with the average temperature of the wettest season (bio8), and geographical and climatic factors are more important for the sexual reproduction (with seeds) of the natural population of the sand whip than asexual reproduction (without seeds), indicating that the environment restricts the sexual reproduction of the sand whip The factors are complex, and its asexual reproduction may be an adaptive performance of a stable population. [ABSTRACT FROM AUTHOR]

The geological conditions of the left bank arch dam foundation of Baihetan Hydropower Station are complex. The dislocation interface with gentle inclination, the anti-dip fault and the columnar jointed basalt are the main important factors which influence the deformation response during excavating the slope. The shear deformation characteristics and mechanism of the left bank of Baihetan arch dam foundation were analyzed based on the monitoring data. The characteristics of shear deformation of the dislocation interface LS3319 was reproduced by UDEC. The calculation results show that during the excavation process of the dam foundation above E.L. 630 m, LS3319 has a significant influence to the local stress status of the slope before and after it's exposed in the excavation surface. The rock mass of the upper and lower parts of LS3319 reveals different deformation characteristics; the stress will be concentrated in the upper part firstly and then unloading and relaxation during the excavation surface bench down. Below E.L.630 m, the shear deformation will also occur due to the influence of dislocation interface LS331, rock mass of the upper part of LS331 will behave as relaxation at the same time. The shear deformation of the dislocation interface mainly occurs during the excavation and exposure process of dam foundation surface and the magnitude of the shear deformation mainly is controlled by in-situ stress conditions, mechanical parameters and occurrence of dislocation interface. [ABSTRACT FROM AUTHOR]

BACKGROUND: Sacral resection has now become the accepted treatment of choice for malignant tumors of the sacrum. There are few biomechanical studies on whether fractures or sacroiliac joint spondylolisthesis will occur after simple sacral resection, and there is no consensus on whether the weight can be fully loaded after subtotal sacral resection and when to rebuild. OBJECTIVE: To contrast clinical research and analyze Von Mises stress to provide a credible theoretic basis about which level of sacrectomy without spinopelvic reconstruction is acceptable for pelvic stability through the biomechanical testing of intact pelvis and models of pelvis after subdivided sacrectomy. METHODS: (1) Biomechanical research: Six fresh normal adult human cadaveric L5-pelvis specimens were chosen. Compressive stress loaded on the specimens was increased by 200 N, until 1 000 N, at the speed of 1.4 mm/min. The change of Von Mises stress was measured to the same pelvic specimens on intact sacrum and groups of subdivided sacrectomy. The differences were compared between groups of data. (2) Clinical studies: Totally 15 patients diagnosed with high sacral tumor with tumor resection between January 2012 and June 2019 were enrolled, including 6 males and 9 females with an average age of 46.40±14.94 years. According to preoperative MRI examination, the extent of sacral involvement was determined, and the size of sacral resection was determined. No reconstruction was performed after operation. Postoperative function and complications were recorded. RESULTS AND CONCLUSION: (1) Biomechanical research: With the growth of the sacrum resection plane, Von Mises stress had different increases at different test points, particularly by 1/4 S1 to 1/2 S1, which were apparently different with that in other groups (P < 0.05). Compared with group 2/3 S2 and group 1/3 S2, the change of Von Mises stress at point A in group S1-2 was not statistically significant. (2) Clinical results: Among the 15 patients, 4 patients retained the intact S1 vertebral body during the operation (resection of the S1-S2 intervertebral space, as in the biomechanics experiment S1-2 group); sacrum was resected in 3 patients as the group 2/3 S2 during the operation, and sacrum was resected in 2 patients during the operation as group 1/3 S2; and the S1 and S2 vertebrae were kept intact in 6 patients (as resection in the S2-3 group). The mean score of musculoskeletal tumor society was 25.27±3.79. All patients were able to walk, nine without walking aids, six with walking aids, one of them developed residual sacral fracture. (3) With the growth of the sacrum resection plane, Von Mises stress at residual sacrum rapidly rose. When the sacrum was resected by S1-S2 intervertebral space, the stability of the pelvic ring was acceptable without spinopelvic reconstruction. [ABSTRACT FROM AUTHOR]

To investigate the influence of the improved vascular intubation and the end to end vascular anastomosis on the blood circulation, survival and motor function of severed fingers in patients with replantation. The clinical data of 107 cases of patients with replantation of severed fingers who were treated in our hospital from January 2017 to December 2018 were retrospectively selected. According to the different operative methods, the patients were divided into group A (n=55, 93 severed fingers in total) and group B (n=52, 86 severed fingers in total). Group A was treated with end to end vascular anastomosis, and group B was treated with improved vascular intubation. The blood circulation, survival, motor function, quality of life and complications of the two groups were compared. The filling time of capillaries and microcirculation of the affected fingers test value in group B were lower than those in group A, while the oxygen saturation and transcutaneous oxygen partial pressure were higher than those in group A (P<0.05). The survival rate, normal tension rate and normal color rate of severed fingers in group B were higher than those in group A (P<0.05). The scores of physiological field, social relationship field, psychological field and environmental field in group B at 1 year after operation were higher than those in group A (P<0.05). The scores of activity, muscle strength, dexterity and Carroll scale in group B were higher than those in group A (P<0.05). There were no significant differences in the incidence of complications between the two groups (P>0.05). Compared with the method of end to end vascular anastomosis, improved vascular intubation for replantation of severed fingers, it the improvement effect is better in the aspects of blood circulation, survival, motor function and quality of life of severed fingers, and will not increase the incidence of complications. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of preoperative acetaminophen and gabapentin on opioid consumption and nausea and vomiting in patients undergoing video-assisted thoracoscopic lobectomy. Method (s): Patients who underwent video-assisted thoracoscopic lobectomy for non-small cell lung cancer from January 2016 to December 2018 were enrolled. Clinical data were collected including age, gender, BMI, comorbidities, anesthesia classification of American Society of Anesthesiologists, Tumor grading, tumor location, surgery time, intraoperative and postoperative opioid consumption, postoperative antiemetic application, opioid consumption was converted to oral morphine equivalent. Patients were divided into two groups according to whether preoperative analgesic regimen with acetaminophen and gabapentin was used. The preoperative basic conditions and the use of opioids during and after surgery were compared between the two groups. The effects of acetaminophen and gabapentin preemptive analgesia regimen on the use of opioids were analyzed. Result (s): A total of 241 patients were included in the study. 78 patients underwent preoperative analgesic regimen with acetaminophen and gabapentin, and 163 patients did not take this analgesic regimen. The doses of opioids, number of vomiting in 24 hours after surgery, and postoperative antiemetic in patients with preemptive analgesia were lower than those without preemptive analgesia. There was no significant difference in postoperative NSAIDs usage and sedation between the two groups. Conclusion (s): Preoperative analgesic regimen with acetaminophen and gabapentin can reduce the dose of opioids during and after surgery for patients undergoing video-assisted thoracoscopic lobectomy, and reduce postoperative nausea and vomiting. [ABSTRACT FROM AUTHOR]

Deep learning methods such as convolutional neural networks(CNN) have been widely used in fields of image processing and object recognition.However,the SAR images cannot yet be efficiently detected by CNN methods.Compared with traditional images,the SAR images have the advantage of all-day and all-weather acquisition,but they cannot obtain enough annotation due to the difficulty for interpretation and short of users.This paper proposes a SAR target detection method based on scene synthesis and anchor constraint.Firstly,the target and its shadow are segmented by region growing as well as threshold algorithm,and then the target detection data set is synthesized by randomly embedding the reasonable region into the SAR complex scene.Considering the SAR target’s geometric characteristics and image resolution parameters,the anchor’s size of Faster-RCNN is constrained to reduce the candidate frames that cannot meet the SAR target detection frame size,which massively reduce redundancy calculations so as to improve the efficiency and accuracy of training and testing process. [ABSTRACT FROM AUTHOR]

Objective: To summarize the experience, methods and clinical effects of systemic and local antibiotics in the treatment of acute hematopoietic osteomyelitis, especially in severe cases. Methods: A retrospective analysis was performed on 12 cases of acute hematopoietic osteomyelitis who were treated in the second hospital affiliated to Air Force Military Medical University (AFMU) during November 2016 to April 2019, among which 3 cases were with sever e sepsis complicated with pulmonary abscess. The patients were firstly treated with empiric systemic antibiotics, followed by bacteriological analysis. Then systemic antibiotics were adjusted according to the results of microbial culture and drug sensitivity. Calcium sulfate/calcium phosphate complex loaded with vancomyc in was applied for local release of antibiotics. The outcome of laboratory and radiological examination before and after treatment were analyzed. Results: Bacteriological culture showed 10 cases of staphylococcus aureus, 1 case of human staphylococcus and 1 case of enterobacter cloacae. The mean follow-up was 56.6 weeks. White blood cell (WBC), neutrophil (NEUT%), erytlrrocyte sedimentation rate (ESR), high sensitivity c-reactive protein (hs-CRP) and other indicators all returned to normal range after treatment. Radiological examination showed a successful bone reconstruction with good osteogenesis and no infection recurrence. 11 out of the 12 patients were treated successfully, with a cure rate of 91.7 % . 1 patient developed chronic osteomyelitis and recovered after the second stage of operation, among which 3 patients with osteomyelitis accompanied by sepsis and pulmonary abscess were cured by systematic antibiotics and surgical treatment successfully. Conclusions: Methicillin Sensitive Staphylococcus Aureus (MSSA) is the most common pathogen for acute haematopoietic osteomyelitis. Treatment should be based on early diagnosis. Firstly, we should use antibiotics empirically, and then choose sensitive antibiotics according to the results of drug sensitivity. Oxacillin plays a significant role in the treatment of 3 severe cases with sepsis and pulmonary abscess. Meanwhile, calcium sulfute/calcium phosphate composite loaded with vancomyc in not only achieve local anti-infection effect, but promote the formation of new bone. The treatment effectively eliminate infection, control sepsis and pulmonary abscess with satisfactory clinical efficacy. [ABSTRACT FROM AUTHOR]

As one of the rice varieties, ratoon rice has the advantages of making full use of temperature and light resources, saving seed, labor, water and pesticide, improving land use efficiency, increasing production and income. The first crop of ratoon rice is often harvested in wet and soft soil and requests high stubble and low rolling rate and degree. However, the rolling rate of common harvester is as high as 40%-50%, which seriously affects the yield of ratoon rice, resulting in significant reduction of economic benefits of ratoon rice production. According to the needs of mechanized harvest and low rolling rate of first crop of ratoon rice, a double-channel feeding harvester for ratoon rice was designed according to the growth characteristics of ratoon rice based on previous researches and theoretical methods proposed by the research group. The machine was mainly composed of a tracked chassis, a header, two sets of threshing and cleaning devices and straw crushers which were bilateral symmetry, a grain bin, an engine and transmission system, and the harvester could realize the process of straw separating, plant-poking, cutting, transporting, threshing, cleaning, straw crushing, grain transporting, grain holding and grain unloading in one time. Compared with the common harvester, by adopting the structure that two sets of working parts share one walking chassis, the weight of the double-channel feeding harvester for ratoon rice was reduce and the damage degree of rolling on the rice stubble was low. According to the harvest rolling model of ratoon rice harvester, the structural parameters were set as the cutting width was 3 000 mm, the track gauge was 1 500 mm, the track width was 400 mm and the grounding length was 1 800 mm. A special header with two channels was designed, which shortened the distance of straw transportation, mitigated the blocking of header, and effectively balanced the power consumption and reduced the vibration by transferring the power separately. Two sets of independent telescopic finger mechanism was adopted which could avoid deformation due to long eccentric shaft, and it was determined that the initial circumferential angle of the two spiral blades in the middle of the two-way spiral conveyor was 180° based on the theoretical analysis. To ensure that the long straw after threshing and cleaning was crushed and scattered to the harvested area, by analyzing the scattering range of straw crusher, it was ascertained that the inclination angle of the outer plate of the tail plate was 8.2°, the inclination angle of the inner plate was 6°, and the angle between the upper cover plate and the vertical direction was 63°. Longitudinal axial threshing cylinder was adopted for threshing. Through analyzing the rolling rate and productivity, it was determined that the available volume of grain bin was 1.5 m³, which could hold 900 kg grain. Harvesting performance was tested according to relevant standards, the major performance evaluation indicators consisted of working speed, feeding rate, loss rate, impurity rate, crushing rate and productivity. The PL60 4LZT-6.0ZC1 harvester of ZOOMLION was used as a contrast. It was suggested from the field test that this machine had stable performance and smooth operation. The tail straw crusher could guide the broken straw into the rolling area, the working speed could reach 0.8 m/s, the feeding rate was 4.6 kg/s, the total loss rate was 2.1%, the impurity rate was 0.4% and the crushing rate was 0.2%. The straight rolling rate was as low as 26.7%, which was 16.2% lower than that of the contrast. The yield of ratoon rice in the first season was 10 175.4 kg/hm², the yield in the second season was 6 013.5 kg/hm², and the total yield in the first and second season was 16 188.9 kg/hm². In control area harvested by the common harvester, the yield of ratoon rice in the first season was 10 175.4 kg/hm², the yield in the second season was 4 854.6 kg/hm², and the total yield in the first and second season was 15 030 kg/hm². Compared with the common harvester, the yield increased by 23.9% (1 158.9 kg/hm²) in the second crop harvested by the double-channel feeding harvester. This research could provide valuable reference for the research and extension of ratoon rice mechanical harvesting technology in the middle and lower reaches of Yangtze River. [ABSTRACT FROM AUTHOR]

Objective: To investigate the occurrence of neuropathic pain and related risk factors after thoracic surgery. Method(s): The clinical data of patients who underwent thoracic surgery in our hospital from 2015 to 2016, including patients' age, gender, smoking history, BMI, preoperative use of hypnotics, preoperative diagnosis, surgical side, surgical approach, whether it was minimally invasive, the use of epidural analgesia pump, intraoperative blood loss, duration of surgery, tube drainage time and whether neuropathic pain occurred were retrospectively collected. The clinical data of patients with neuropathic pain and without were comparably analyzed. Multivariate logistic regression analysis was performed on the differential clinical data to explore the risk factors of neuropathic pain. Result (s): A total of 123 patients were enrolled in the study. 33 patients (26.8%) had postoperative neuropathic pain. 6 patients (4.9%) had persistent neuropathic pain for one year after surgery. The time for postoperative neuropathic pain was on the 7th day after surgery and the duration was 75 days. The smoking proportion (81.8%), the proportion of hypnotics before surgery (57.6%), the proportion of thoracotomy (81.8%), and the amount of intraoperative blood loss ( 185 mL), operative time (196 minutes), and postoperative drainage time (2.5 days) of patients with neuropathic pain were higher than those without neuropathic pain. Multivariate analysis showed that preoperative use of hypnotics (OR=2.322, P<0.001 ), prolonged operative time (OR=3.703, P<0.001), and prolonged postoperative drainage time (OR=2.675, P=0.002) were the risk factors of neuropathic pain. Conversely, Video-assisted thoracoscopic surgery is a protective factor (OR=0.453, P=0.002). Conclusion (s): Preoperative use of hypnotics, and prolonged operative time and postoperative drainage time increase the risk of neuropathic pain. Video-assisted thoracoscopic techniques can reduce the incidence. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective:To compare the early clinical efficacy of traditional unilateral thoracoscopic techniques and three ports thoracoscopic thymectomy in the treatment of myasthenia gravis and effect on the quality of life. Methods: From January 2012 to June 2016, 115 patients with myasthenia gravis who underwent thoracoscopic thymectomy in our hospital were collected. According to the surgical procedure, 47 and 68 patients were divided into the traditional unilateral thoracoscopic group and the three ports thoracoscopic group under the xiphoid and costal margin respectively. The basic data including gender, age, thymoma, duration of disease, follow-up time and preoperative Osserman scores, the operation time, intraoperative blood loss, postoperative drainage time, postoperative drainage volume, ICU duration time, postoperative hospital stay, postoperative complications, pain scores, quality of life scores at different time points after surgery, and the post-hospital status at the last follow-up were reviewed and compared between two groups. Result: There was no differences in the age, sex ratio, thymoma status, duration of disease, follow-up time, and preoperative Osserman score between the two groups (P>0.05). The operation time, intraoperative blood loss, ICU duration time and postoperative hospital stay of three ports group were all lower than those of the traditional group (P<0.05). There was no significant difference in the incidence of postoperative complications (phrenic nerve palsy, pleural effusion, Wound fat liquefaction) between the two groups (P>0.05). The pain scores of three ports group were all significantly lower than those in the conventional group during 3 days after surgery and at discharge (P<0.05). There was no significant difference in the effective rate and quality of life scores (MGQOL-15 scores) at the preoperative, postoperative, and last follow-up between the two groups (P>0.05). At the last follow-up of the three ports group, the improvement in female MGQOL-15 score (11.2± 3.3 points) was higher than that in men (7.4± 2.7 points) (P<0.001). Patients with Osserman scores of 3 and 4 scored had significantly higher MGQOL-15 scores increment (10.7± 3.7 points) than those with Osserman scores of 2 (5.0± 1.9 points) (P<0.001). Conclusion: Three ports thoracoscopic resection of the thymus under the xiphoid and costal margin has the characteristics of short operation time, less intraoperative blood loss and quick recovery after operation in the treatment of myasthenia gravis, it can effectively relieve the postoperative pain and improve the quality of life. Additionally, women benefit more than men. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects and the mechanism of action of microRNA-155(miR-155) on proliferation,invasion and migration of osteosarcoma Saos2 cells. Methods: The expression of miR-155 in normal osteoblasts and osteosarcoma Saos2 cells was detected by real-time PCR, and the transfection efficiency of miR-155-mimic and miR-155-inhibitor was measured by qRT-PCR. CCK-8 assay was used to evaluate the cell proliferation. Transwell assay and wound healing assay were used to detect the invasion and migration ability of Saos2 cells, respectively. SOCS1 and p-STAT3 protein expression was examined by using western blot assay. Dual luciferase reporter gene assay was performed to determine the target gene. Results: The expression of miR-155 was significantly higher in osteosarcoma Saos2 cells than normal osteoblasts(P <0.001). After transfection with miR-155-mimic or miR-155-inhibitor, miR-155 expression of Saos2 cells was significantly upregulated or downregulated, respectively(P <0.001).Overexpression of miR-155 promoted proliferation, invasion and migration of Saos2 cells, and decreased the protein level of SOCS1, as well as increased the phosphorylation level of STAT3. The difference was statistically significant(P<0.05). Conversely, downregulation of miR-155 inhibited the proliferation, invasion, and migration of Saos2 cells. The difference was statistically significant(P <0.05).Conclusion: miR-155, which is highly expressed in osteosarcoma Saos2 cells, can activate the STAT3 signaling pathway by inhibiting the expression of SOCS1, thereby promotes cell proliferation, migration and invasion. Therefore, targeting miR-155 therapy may be a potential approach for osteosarcoma. [ABSTRACT FROM AUTHOR]

Objective: To investigate the risk factors of pulmonary complications after thoracoscopic lobectomy. Methods:Consecutive patients who underwent thoracoscopic lobectomy in our department for lung cancer from January 2015 to June 2017 were collected. Patients’ basic informations, including gender, age, percentage of expiratory volume of the first second(FEV1%), American Society of Anesthesiologists scores(ASA), BMI index, Chronic obstructive pulmonary disease(COPD) incidence and tumor status, were reviewed. The postoperative hospital stay, ICU stay time, and hospital mortality were counted, and the postoperative pulmonary complications, postoperative first day activities, and physiotherapy were recorded. The differences between patients with pulmonary complications and non-complication were comparatively analyzed, and Logistic regression was used to analyze the independent risk factors for pulmonary complications among the differential factors. Results: According to the exclusion criteria, a total of 256 patients were included in the study, including 126 males, and the average age was 67.2 ±13.7 years. A total of 19 patients(7.4%) developed pulmonary complications. Patients with pulmonary complications had longer postoperative hospital stay, longer ICU stay, and higher mortality(P<0.05). Patients with pulmonary complications have poor postoperative activity. There were significant differences in age,COPD, and smoking between the two groups(P<0.05), but logistic regression analysis found that smoking was an independent risk factor for postoperative pulmonary complications. Conclusions: Postoperative pulmonary complications in patients undergoing thoracoscopic lobectomy have increased postoperative mortality, and smoking is an independent risk factor for postoperative pulmonary complications in patients. [ABSTRACT FROM AUTHOR]

The high slope geological disaster is easily happened, and it can block the transportation and delay the disaster relief in choke points of mountainside roads. Considering site condition, construction difficulty, tunnel safety, structure reliability, convenience and waterproof, the hangar tunnel scheme was applied in the section of Longsheng-Ziyuan road line. The finite element analysis software was used to calculate the forces of hangar tunnel structure under different situations. The results show that the force of the main parts of hangar tunnel is in safety range. The structure design with high force is optimized to enhance the safety factor of hangar tunnel. After experiencing high slope disasters of landslides and falling rocks during the operation phase, no obvious diseases are found in the arched hangar tunnel structure, and the traffic on the section is not affected. [ABSTRACT FROM AUTHOR]