Autonomous Control Reconfiguration of Aerospace Vehicle Based on Control Effectiveness Estimation

Future aerospace vehicles （ASV） are designed to fly in both inner and extra atmospheric fields, which requires autonomous adaptability to the uncertainties emanated from abrupt faults and continuously time-varying environments. An autonomous control reconfiguration scheme is presented for ASV to deal with the uncertainties on the base of control effectiveness estimation. The on-line estimation methods for the time-varying control effectiveness of linear control system are investigated. Some sufficient conditions for the estimable system are given for different cases. There are proposed corresponding on-line estimation algorithms which are proved to be convergent and robust to noise using the least-square-based methods. On the ground of fuzzy logic and linear programming, the control allocation algorithms, which are able to implement the autonomous control reconfiguration through the redundant actuators, are put forward. Finally, an integrated system is developed to verify the scheme and algorithms by way of numerical simulation and analysis.

Effectiveness of Cyhalofop-butyl EW for Control of Poaceae Weeds in Transplanted Rice in China

[Objective] This study aimed to investigate the effectiveness of different rates of 10% cyhalofop-butyl EW for control of Poaceae weeds in transplanted rice in China. [Method] The experimental and eco-friendly herbicide, 10% cyhalofop-butyl EW, was applied in field trials in 2013 to investigate its efficacy in five representa-tive rice producing areas, one in each of the provinces Anhui, Hunan, Zhejiang, Jiangsu and Liaoning. [Result] The results showed that 10% cyhalofop-butyl EW could effectively control Poaceae weeds in transplanted rice without negative effects on the rice crop. The optimal application rate of 10% cyhalofop-butyl EW was found to be 750-1 500 ml/hm2. [Conclusion] The study confirmed that 10% cyhalofop-butyl EW has clear potential for wide-spread adoption in rice production systems.

Synergistic effects of the entomopathogenic fungus Isaria javanica and low doses of dinotefuran on the efficient control of the rice pest Sogatella furcifera

The rice planthopper,Sogatella furcifera,is a piercing-sucking insect pest of rice,Oryza sativa.It is responsible for significant crop yield losses,and has developed moderate to high resistance to several commonly used chemical insecticides.We investigated the effects of the insect fungal pathogen Isaria javanica,alone and in combination with the chemical insecticide dinotefuran,on S.furcifera under both laboratory and field conditions.Our results show that I.javanica displays high infection efficiency and mortality for different stages of S.furcifera,reducing adult survival,female oviposition and ovary development.Laboratory bioassays showed that the combined use of I.javanica with a low dose(4-16 mg L^(-1))of dinotefuran resulted in higher mortality in S.furcifera than the use of I.javanica or dinotefuran alone.The combined treatment also had more significant effects on several host enzymes,including superoxide dismutase,catalase,peroxidase,and prophenol oxidase activities.In field trials,I.javanica effectively suppressed populations of rice planthoppers to low levels(22-64%of the level in untreated plots).Additional field experiments showed synergistic effects,i.e.,enhanced efficiency,for the control of S.furcifera populations using the combination of a low dose of I.javanica(1×10^(4) conidia mL^(-1))and a low dose of dinotefuran(~4.8-19.2%of normal field use levels),with control effects of>90%and a population level under 50 insects per 100 hills at 3-14 days post-treatment.Our findings indicate that the entomogenous fungus I.javanica offers an attractive biological control addition as part of the integrated pest management(IPM)practices for the control of rice plant pests.

A Comparative Analysis of the Control Effect of Medical Expenses between General Hospitals and Traditional Chinese Medicine Hospitals from 2012 to 2021

Objective To analyze the changing trend of average medical expenses and structure in general hospitals and traditional Chinese medicine(TCM)hospitals and the effects and differences achieved by the two kinds of hospitals through controlling unreasonable growth of medical expenses,so as to provide reference for controlling the rapid rise of medical cost in public hospitals and optimizing the cost structure.Methods Based on the changes of related indicators of medical expense control from 2012 to 2021,the overall characteristics,changes of cost structure and trends of medical expenses in general hospitals and TCM hospitals were investigated.Results and Conclusion From 2012 to 2021,the increase of medical expenses in general hospitals and traditional Chinese medicine hospitals had slowed down,the proportion of drug revenue to medical income began to decline,and the medical service income increased.However,the proportion of inspection,test and sanitary materials income has increased instead of decreasing,but the management cost has decreased.The two kinds of hospitals have achieved certain cost control results,the structure of medical cost has changed greatly,and the technical service and labor value of medical personnel have been reflected to a certain extent.However,it is still necessary to explore a more scientific and reasonable cost control mechanism to promote the further optimization of medical cost structure.

Control Effect of Sublimed Sulfur Paired with Acaricide on Bee Mites

[Objective] This study aimed to compare the effects of sublimed sulfur and acaricide on controlling bee mites.[Method] Three independent experiments were carried out in the same apiary during 2007-2009.[Results] The results showed that this method is effective in eliminating mites settled on combs or hidden during pupae phase,but not in controlling the mites parasitized on adult bees.The control effect on killing Varroa destructor after treated appeared optimal in the first day and then decreased,and that on killing Tvopilaelaps clareae happened in the second day.The results indicated that the effect would be much better if the bees can be treated 1 time to 2 times again in the following 2-5 days after the first treatment.Back to data pool,we found that the treatment of sublimed sulfur paired with acaricide is effective in controlling V.destructor and T.clareae.[Conclusion] This technique could facilitate the apicultural production in the regions suffered from V.destructor and T.clareae.

Occurrence Regularity and Control Research of Apple Early Defoliation Disease in West Sichuan Plateau

[ Objective ] The research aimed to discuss the occurrence regularity of apple early defoliation disease and control effects of fungicides in west Sichuan plateau. [ Method ] Apple early defoliation disease in west Sichuan plateau was systematically investigated during 2009 and 2011, and the control effects of different fungicides during different spraying periods were studied. [ Result] The species of pathogen mainly was Marssonina ma/i （ P. Henn）, accounting for 32.5%, Phyl-losticta Pirina Sa accounted for 29.9%, and Alternaria mali Roberts accounted for 25.7%. The field fluctuation regularity was as follows ： the disease generally be- gan in the mid-May and ended in early and middle October with only one damage peak during the whole year, the fluctuation had positive correlation with rainfall （ R2 =0.891 8 ＊ ＊ ）. Control test showed that 40% flusilazole had the best control effect （86.5%）, which was best to apply after anthesis. [ Conclusion ] The paper provided theoretical basis for the effective control against apple early defoliation disease.

Research on the Control Effects of Several Insecticides on Wheat Aphids

[Objective] The aim was to determine control effects of the 6 insecticides and recommended the optimal doses. [Method] In 2014, the control effects of sophocarpidine, pymetrozine, beta-cypermethrin, acetamiprid, imidacloprid, and chlor- pyrifos on wheat aphids were tested, and every pesticide was designed with three doses in Shou County, Anhui Province, to explore the significance of differences on control effects. [Result] The results showed that the control effects of the 6 insecti- cides were satisfied, and the insecticides were safe on wheat. [Conclusion] During initial diseasing stage of aphid, it is recommended to use sophocarpidine soluble concentrate （1.5%）, pymetrozine water dispersible granule （50%）, imidacloprid wet- table powder （25%）, and acetamiprid wettable powder （5%）, and chlorpyrifos missi- ble oil （40%）, cypermethrin missible oil （4.5%） and imidacloprid wettable powder （25%） can be applied in peak-diseasing stage.

Control Effects of Bacillus subtilis DJ-6 and Pyraclostrobin Alone and in Combination Against Fusarium oxysporum

[Objective] This study was conducted to screen a synergistic biological fungicide complex to control Fusarium wilt, reducing the use of chemical pesticides. [Method] The inhibitory effects of Bacil us subtilis DJ-6 and pyraclostrobin alone or in combination at five ratios against Fusarium oxysporum were detected by mea-suring mycelium growth rate in laboratory tests. The growth promotion and disease control effect of combined or single use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000, 1∶2 000 and 1∶3 000 dilutions were detected in field trials. [Result] The EC50 values of combined use of B. subtilis DJ-6 and pyra-clostrobin at ratios of 1∶1, 1∶2, 1∶3, 1∶4 and 1∶5 against F. oxysporum were 5.311 5, 4.008 6, 3.570 6, 3.350 9 and 3.218 9 μg/ml, with the synergistic ratios （SR） of 2.28, 1.77, 1.53, 1.64, 1.11, among which the synergetic effect at 1∶1 was the best. The fungicidal activity of pyraclostrobin was greater than that of B. subtilis DJ-6 in laboratory tests. Field trials revealed that al the 1∶1 000, 1∶2 000 and 1∶3 000 dilu-tions of 20% pyraclostrobin·2×1011 cfu/g B. subtilis DJ-6 WP in combination, 1∶1 000 dilution of 1 ×1012 cfu/g B. subtilis DJ-6 WP and 1∶2 000 dilution of 250 g/L pyra-clostrobin EC promoted the growth of strawberry by increasing plant height, leaf petiole, leaf blade area and stem diameter. Among them, the treatments with 1∶1 000 and 1∶2 000 of 20% pyraclostrobin · 2×1011 cfu/g B. subtilis DJ-6 WP in combina-tion had better effects than other treatments. The control effects of al the treat-ments were measured 30 and 80 d after fungicide application. The control effects of 1∶1 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combina-tion were up to 100% and 93.11%, which were higher than those in al other treat-ments. The second highest control effects were found in the treatment with 1∶ 2 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination, they were 92.49% and 86.49%, higher than those in other treatments except the 1∶1 000 dilution of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 in combination. The control effects of 1∶3 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination were 82.61% and 72.42%, higher than those in treatment with 1∶1 000 dilution of 1×1012 cfu/g B. subtilis DJ-6 WP, but lower than those in treat-ment with 1∶2 000 dilution of 25% pyraclostrobin EC. [Conclusion] Al the results re-vealed that the combination use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000 to 1∶2 000 dilution had better control effect against strawberry Fusarium wilt.

Substructure design optimization and nonlinear responses control analysis of the mega-sub controlled structural system (MSCSS) under earthquake action

The newly proposed mega sub-controlled structure system(MSCSS)and related studies have drawn the attention of civil engineers for practice in improving the performance and enhancing the structural effectiveness of mega frame structures.However,there is still a need for improvement to its basic structural arrangement.In this project,an advanced,reasonable arrangement of mega sub-controlled structure models,composed of three mega stories with different numbers and arrangements of substructures,are designed to investigate the control performance of the models and obtain the optimal model configuration(model with minimum acceleration and displacement responses)under strong earthquake excitation.In addition,the dynamic parameters that affect the performance effectiveness of the optimal model of MSCSS are studied and discussed.The area of the relative stiffness ratio RD,with different mass ratio MR,within which the acceleration and displacement of the optimal model of MSCSS reaches its optimum(minimum)value is considered as an optimum region.It serves as a useful tool in practical engineering design.The study demonstrates that the proposed MSCSS configuration can efficiently control the displacement and acceleration of high rise buildings.In addition,some analytical guidelines are provided for selecting the control parameters of the structure.

Effect of Four Pesticides on Controlling Autumn Cowpea Greenhouse Whitefly

In order to mitigate the occurrence and damage of cowpea whitefly, reduce chemical pesticide consumption, residue and environmental pollution, the methods of forecasting, randomized block design andstatistical analysis were used in field efficacy trials, to study the control effect of cowpea anthracnose by usingchemical pesticides dinotefuran, acetamiprid, pymetrozine, and bio-pesticide avermectin. The results showed that after applying 1.85% avermectin EC 375 g, 20% dinotefuran SP 600 g, 5% acetamiprid WP 600 g, and 25% pymetrozine WP 600 g （control pesticide） per hm2 once every 5-8 days, and 3 times continuously underserious autumn occurrence of greenhouse whitefly, the control efficacy was 90.9%, 97.0%, 88.0%, 93.9%respectively on the 7th day after the pesticides application; 97.4%, 92.1%, 84.2%, 89.4% respectively on the 14th day after the pesticides application; and 95.6%, 86.7%, 82.2%, 84.5%, respectively on the 20th day afterthe pesticides application. The control effects among avermectin, acetamiprid and pymetrozine were not significantly different, while the effects of avermectin and pymetrozine were significantly higher than that of acetamiprid on the 7th day. The control effects among avermectin, dinotefuran and pymetrozine were not significantly different, while significantly higher than that of acetamiprid on the 14th day. The control effect of avermectin was significantly higher than that of dinotefuran, acetamiprid and pymetrozine on the 20th day. Meanwhile, the control effect of avermectin was slightly lower, higher and much higher than that of dinotefuran on the 7th, 14th, 20th day respectively after the treatment. These results indicated that the four pesticides,especiaLly biopesticide avermectin, were ideal pesticides, which could not only be used for controlling cowpea whitefly, but also realize modern, green, organic and ecological agricultural production.

Control Effect of Vegetable Oil on Cucumber Powdery Mildew

[Objective] The study discussed the indoor activity and field control effect of vegetable oil on cucumber powdery mildew.[Method] The cucumber seedlings of Changchunmici were adopted as the material,which were inoculated with the fungus pathogen of cucumber powdery mildew naturally occurred in the field.The indoor protective test and field test were performed respectively to observe the control effects of different plant oils EC on the cucumber powdery mildew.[Result] When six plant oils EC including cottonseed oil,soybean oil,canola oil,corn oil,sesame oil and sunflower oil was diluted into 10 and 5 ml/L,they had better control effect on cucumber powdery mildew.As for the indoor protective effect,the protective effect of the vegetable oil EC was equivalent to the control agent triadimefon EC,the field control effect of vegetable oil EC was in the range of 60%-75%,which was consistent with 69%-70% control effect of contrast agent with 1 ml/L triadimefon EC dilution.[Conclusion] All vegetable oils EC had significant control effect on cucumber powdery mildew in the test.

Application of Spodoptera litura Nucleopolyhedrovirus for Crop Pest Control

The laboratory bioassay and field control efficacy of Spodoptera litura nucleopolyhedrovirus（Spli NPV） Chenzhou strain were preliminarily examined. The efficient artificial propagation method was to feed the host larvae with virus suspension,and the average mortality of the insects was 65.0%. The death peak of the pests appeared 4-8 d after virus infection. The high temperature, high humidity and poor light could help the virus infection and propagation. Filed control efficacy of Chenzhou strain was 86.6% in laboratory, which was better than of another commercial strain. The corrected control efficacy of this strain was 88.4% the field, which was higher than that of avermectin pesticide significantly. It was detected that the occlusion body（OB） concentration of the initial virus＇ s stock solution was 1.03×1011OBs/ml,and it was a strong SpliNPV strain, as it showed an excellent efficacy to control the pest Spodoptera litura, and thus there will be a good prospect of application and development of this SpliNPV strain.

Occurrence and Control of Pear Blight Rot(Phytophthora cactorum) in Qianxian of Shaanxi Province

[ Objective ] The paper was to investigate the occurrence condition of pear blight rot in pear-producing areas in Qianxian of Shannxi Province, so as to find the main cause of the disease and the effective agents for the disease. [Method] The occurrence condition of pear blight rot was surveyed in field, the inci- dence rate of trees and incidence index of fruits were counted, and the field control test of different agents against pear blight rot was carried out. [ Result] The ma- jor reasons for outbreak of pear blight rot in Ganhe pear-producing areas in Qianxian of Shannxi Province were excessive rainfall and high temperature and humidity in July 2010, poor drainage in orchards and large planting density were also the main factors causing outbreak of pear blight rot. 64% oxadixyl · mancozeb WP, 60% metalaxyl-mancozeb WP and 80% aliette WP had significant control effect on pear blight rot, fruit bagging was also an ideal measure for prevention of the dis- ease. [ Conclusion] Pear production should focus on improving the air and light condition, enhancing the drainage capacity of orchard and promoting bagging culti- vation, and the systemic control agents should be selected to control pear blight rot.

Study on the control of rice stripe disease with Bilken virusicide

The paper reviewed the function mechanism of Bilken virusicide against rice stipe disease, and then introduced its control effects in field test as well as its application method.

Control Effect of Methanol Extract of Blumea megacephala Chang et Tseng against Turnip Aphid (Lipaphis erysimi Kaltenbach)

[ Objective ] The paper was to explore the application of botanical pesticides on controlling turnip aphid （ Lipaphis erysimi Kaltenbach）. [ Method ] Through potting efficacy experiment of Chinese cabbage, the control effects of two preparations（20% EC and 10% EW）of methanol extract of Blumea megacephala Chang et Tseng against turnip aphid, as well as leaf-protection effect on Chinese cabbage were determined. [ Result] 20% EC of B. megacephala had the highest efficacy in 10-fold dilution, and its control effects against turnip aphid were 57.78%, 77.19% and 84.79% after pesticide spraying for 24, 48 and 72 h; 10% EW of B. megacephala had the highest efficacy in 5-fold dilution, and its control effects against turnip aphid were 74.44%, 84.79% and 89.14% after pesticide spra- ying for 24, 48 and 72 h. The leaf-protection rates of 20% EC orB. megacephala in 10-fold dilution were 89.31% and 94.80% after pesticide spraying for 3 and 5 d; the leaf-protection rates of 10% EW of B. megacephala in 5-fold dilution were 93.50% and 97.83% after pesticide spraying for 3 and 5 d. [ Condusion] The methanol extract of B. megacephala had good control effect against turnip aphid and good protection rate on crops.

Control of Maize Head Smut with 6% Tebuconazole FS

In order to test the control effect of 6% tebuconazole FS on maize head smut and to select its optimal dose for mixing seed, field tests were performed in 2012 and 2013. The results showed that 6% tebuconazole FS was effective to control maize head smut, and the control effect ranged from 73.4% to 91.1%. In addition, it also improved the maize yield by 36.7%-44.1%, compared with the blank control. The optimal dose of 6% tebuconazole FS for seed dressing was 166.5 g/100 kg to control head smut on maize.

Effects of policies and containment measures on control of COVID- 19 epidemic in Chongqing

BACKGROUND Coronavirus disease 2019(COVID-19)is an emerging,rapidly evolving disease that spreads through the respiratory system and is highly contagious.In March 2020,the World Health Organization declared the COVID-19 outbreak a pandemic.In China,the pandemic was controlled after 2 mo through effective policies and containment measures.Describing the detailed policies and containment measures used to control the epidemic in Chongqing will provide a reference for the prevention and control of COVID-19 in other areas of the world.AIM To explore the effects of different policies and containment measures on the control of the COVID-19 epidemic in Chongqing.METHODS Epidemiological data on COVID-19 in Chongqing were prospectively collected from January 21 to March 15,2020.The policies and prevention measures implemented by the government during the epidemic period were also collected.Trend analysis was performed to explore the impact of the main policy measures on the effectiveness of the control of COVID-19 in Chongqing.As of March 15,the cumulative incidence of COVID-19 in Chongqing was 1.84/100000(576 cases)and the infection fatality rate was 1.04%(6/576).The spread of COVID-19 was controlled by effective policies that involved establishing a group for directing the COVID-19 epidemic control effort;strengthening guidance and supervision;ensuring the supply of daily necessities and medical supplies and equipment to residents;setting up designated hospitals;implementing legal measures;and enhancing health education.Medical techniques were implemented to improve the recovery rate and control the epidemic.Policies such as“the lockdown of Wuhan”,“initiating a first-level response to major public health emergencies”,and“implementing the closed management of residential communities”significantly curbed the spread of COVID-19.Optimizing the diagnosis process,shortening the diagnosis time,and constructing teams of clinical experts facilitated the provision of“one team of medical experts for each patient”treatment for severe patients,which significantly improved the recovery rate and reduced the infection fatality rate.CONCLUSION The prevention policies and containment measures implemented by the government and medical institutions are highly effective in controlling the spread of the epidemic and increasing the recovery rate of COVID-19 patients.

Setting up the Goal of Eliminating Outbreaks of Blue-green Alga, Innovating the Idea of Controlling the Taihu Lake, and Ensuring the Safety of Water Supply in the Taihu Lake

Since the water supply crisis in the Taihu Lake on May 29,2007,the control of the Taihu Lake has achieved remarkable results,and the eutrophication has been greatly reduced.Existing problems are as follows:outbreaks of blue-green alga still appear seriously every year,and there is no goal to eliminate outbreaks of blue-green alga;the load into the lake greatly exceeds the environmental capacity;reed wetlands are greatly reduced;there is still the possibility of a water supply crisis;the research of eliminating outbreak of blue-green alga is weak.In this paper,the experience of controlling the Taihu Lake is summarized,and the ultimate goals of eliminating eutrophication and outbreaks of blue-green alga and restoring wetlands and biodiversity are proposed.Control measures are proposed,such as deepening the promotion of the lake chief system,establishing the lake chief system in an all-round way,and increasing applied scientific and technological efforts and capital investment.The necessity and possibility of further controlling the Taihu Lake to eliminate outbreaks of blue-green alga should be recognized.Relying on controlling eutrophication alone cannot eliminate outbreaks of blue-green alga.The point that phosphorus control is the key to eliminate outbreaks of blue-green alga is not suitable for the Taihu Lake.The integration ideas of"three types"of technologies should be innovated.The first one is"double reduction and double increase"measures to eliminate eutrophication,of which"double reduction"is to reduce external point sources and non-point sources and internal blue-green alga in sediment;for external sources,the treatment standard of sewage plants should be paid special attention to.The second one is"double algae removal"measures to salvage blue-green alga,suppresses and kills algae.The blue-green alga on the surface,middle and bottom of water should be thoroughly salvaged and eliminated from various water areas.The third one is"double restoration"measures to restore wetlands and biodiversity.The area of wetlands should be restored to the area from the 1960s to the 1970s before outbreaks of blue-green alga,and vegetation coverage reaches 25%-30%.The Taihu Lake is controlled in different waters to ensure water supply safety in water sources.Five suggestions are proposed,such as revising the"Overall Plan for the Comprehensive Treatment of Water Environment in the Taihu Lake Basin"again,incorporating the goal of eliminating outbreaks of blue-green alga in the plan,setting up this research topic,greatly improving sewage treatment standards in local legislation.

Size Distributions of Aerosol Sulfates and Nitrates in Beijing during the 2008 Olympic Games： Impacts of Pollution Control Measures and Regional Transport

For the 2008 Olympic Games, drastic control measures were implemented on industrial and urban emissions of sulfur dioxide （SO2）, nitrogen oxides （NOx） and other pollutants to address the issues of poor air quality in Beijing. To investigate the effects of SO2 and NOx reductions on the particulate sulfate and nitrate concentrations as well as their size distributions, size-segregated aerosol samples were collected using micro-orifice uniform deposit impactors （MOUDIs） at urban and downwind rural sites in Beijing before and after full-scale controls. During the sampling period, the mass concentrations of fine particles （PMI.s） at the urban and rural sites were 94.0 and 85.9 p.g m-3, respectively. More than 90% of the sulfates and 60% of nitrates formed as fine particles. Benefiting from the advantageous meteorological conditions and the source controls, sulfates were observed in rather low concentrations and primarily in condensation mode during the Olympics. The effects of the control measures were separately analyzed for the northerly and the southerly air-mass-dominated days to account for any bias. After the control measures were implemented, PM, sulfates, and nitrates were significantly reduced when the northerly air masses prevailed, with a higher percentage of reduction in larger particles. The droplet mode particles, which dominated the sulfates and nitrates before the controls were implemented, were remarkably reduced in mass concentration after the control measures were implemented. Nevertheless, when the polluted southerly air masses prevailed, the local source control measures in Beijing did not effectively reduce the ambient sulfate concentration due to the enormous regional contribution from the North China Plain.

Mechanism and control technology of strong ground pressure behaviour induced by high-position hard roofs in extra-thick coal seam mining

This work aimed at revealing the mechanism of strong ground pressure behaviour(SGPB)induced by high-position hard roof(HHR).Based on the supporting structures model of HHR,a modified voussoir beam mechanical model for HHR was established by considering the gangue support coefficient,through which the modified expressions of limit breaking span and breaking energy of HHR were deduced.Combined with the relationship between the dynamic-static loading stress of supporting body(hydraulic support and coal wall)and its comprehensive supporting strength,the criteria of ground pressure behaviour(GPB)induced by HHR were discussed.The types of Ⅰ_(1),Ⅰ_(2),Ⅱ_(1),andⅡ_(2) of GPB were interpreted.Results showed that types Ⅰ_(1) and Ⅰ_(2) were the main forms of SGPB in extra-thick coal seam mining.The main manifestation of SGPB was static stress,which was mainly derived from the instability of HHR rather than fracture.Accordingly,an innovative control technology was proposed,which can weaken static load by vertical-well separated fracturing HHR.The research results have been successfully applied to the 8101 working face in Tashan coal mine,Shanxi Province,China.The results of a digital borehole camera observation and stress monitoring proved the rationality of the GPB criteria.The control technology was successful,paving the way for new possibilities to HHR control for safety mining.