Search

This paper introduces the current status of domestic and international research on PHA synthe¬sis by organic acid compounding, elucidates the metabolic pathway of PHA synthesis by VFAs, and concludes that the monomeric composition of PHA is directly influenced by the odd-even number of acids in VFAs. The change pattern of VFAs components during anaerobic fermentation of organic waste was discussed, and the performance and yield changes of PHA synthesized by different VFAs components were summarized, pointing out that increasing the masa fraction of odd-numbered acids and increasing the proportion of HV monomers are important ways to optimize the performance of PHA. By summarizing the various regulatory strategies of VFAs, the research directions for the synthesis of high-quality PHA were clarified. Key words: volatile fatty acids; polyhydroxy fatty acid esters; component modulation; performance; anaerobic fermentation [ABSTRACT FROM AUTHOR]

From the perspective of resource recovery, this paper summarized the physical and chemical method ( evaporation method, the remove method, adsorption, membrane separation, magnesium ammonium phosphate precipitation) and recycling organic waste anaerobic biological method and other methods in the fermented liquid ammonia nitrogen form and its mechanism, analyses the anaerobic fermentation liquor pH, temperature, gas liquid ratio and suspended solids and organic matter, high concentration of ammonia nitrogen on the effects of the ammonia nitrogen recycling in view of the existing in the running cost is high, the adsorption capacity is small, membrane fouling and concentration ability is limited and difficult problems such as separation, puts forward the delve into a stable and efficient, low cost, convenient operation, nitrogen recovery technology and combination of the process and optimize the process conditions of research direction, in order to organic waste anaerobic fermentation contained ammonia nitrogen utilization to provide the reference. [ABSTRACT FROM AUTHOR]

In order to explore the negative influence rule of the iron debris abrasive particles in the gearbox on the original lubrication system, based on the principle of electromagnetic induction and STM32F103ZET6 microcontroller as the control unit, a set of gearbox lubricating oil abrasive particles online detection system is designed, and the abrasive particle volume and quantity measurement results of the sample oil and a gearbox oil are compared. With the volume of a single abrasive particle as the index, the cleaning degree of lubricating oil in a gearbox is determined, and the influence of gear running at different speeds on the online measurement results are analyzed. The test results show that the gearbox lubricating oil online detection system has good detection effect. The static detection value of the gearbox is much lower than that of the dynamic detection value. When the input gear of the gearbox dynamic detection is larger than a certain speed threshold, the detection results of the abrasive volume and quantity increase obviously. This research has certain practical value for fault diagnosis and risk warning of the gear lubrication system.

The safety assurance of intelligent mine building in China is intelligent mine ventilation. The idea of intelligent sensing and interactive control of underground ventilation human-machine-loop integrated information flow is pointed out based on the “combination of level and battle” in order to genuinely accomplish intelligent mine ventilation. Additionally, it covers the theory and design of mine intelligent ventilation, as well as accurate monitoring and early warning systems, real-time network problem-solving, fault diagnostics, and intelligent decision-making. Furthermore, it supports the platform structure of the mine intelligent ventilation system, the creation of new sensors for accurate ventilation parameter monitoring and arrangement strategy optimization, the processing of ventilation parameter information flow, the method for solving the wind network, the integration of the mine climate and ventilation network, the solution to the wind network’s response, and the concept of mine intelligent ventilation. To avoid the inaccuracy of point wind velocity measurement brought on by an uneven distribution of wind velocity in shaft section, a novel technique of direct measurement of wind volume in complete section is presented; To increase the precision of real-time wind network solution and the stability of routine operation of intelligent ventilation, a real-time wind resistance adaptive adjustment wind network solving model with heat and humidity coupling has been created. Building a catastrophe evolution model for coal and gas protrusion, fire, and other disasters requires the use of a field-area-network coupling numerical solution approach based on full-size disaster test data. Additionally, based on full-scale disaster test data, it developed a coupled field-area-network numerical solution method, constructed a disaster evolution model for coal and gas protrusion, fire, and gas explosion, and overcame the obstacle to disaster autonomous decision making and control of mine intelligent ventilation system; In conjunction with implementation cases for mine intelligent ventilation, it elaborated the field implementation and operation process of mine intelligent ventilation in regards to precise wind measurement, linkage control of ventilation facilities and equipment, intelligent fire and dust prevention, and pointed out the issues and future direction of mine intelligent ventilation construction.

Pt/Gr catalysts were prepared via both organic sol method and sodium borohydride reduction method (denoted as Pt/Gr-OS and Pt/Gr-SR, respectively) with grapheme oxide (GO) as carrier precursor and chloroplatinic acid with polyvinyl pyrrolidone (PVP) as complexing agent. TEM and XRD were used to characterize the morphology, particle size, and size distribution, and the electro-catalytic performance of the catalysts for methanol oxidation was also investigated by means of cyclic voltammetry and chronoamperometry. The results showed that compared with Pt/C, the Pt/Gr catalysts obtained by using both of the methods had high dispersion and Pt/Gr-OS had higher dispersion that Pt/Gr-SR; Pt/Gr-OS had smaller particle size, larger electrochemical activity specific surface area, and higher electro-catalytic performance on methanol exidation. The electro-catalytic performance of Pt/Gr-OS was 1.7 and 3.8 times as those of Pt/Gr-SR and Pt/C catalysts, respectively. In addition, Pt/Gr-OS had higher stability that Pt/Gr-SR and Pt/C. [ABSTRACT FROM AUTHOR]

Taking into consideration the differences of disaster prevention in gas and spontaneous combustion of coal seam and goaf cross-scale fracture fields, the cross-scale fractures field of coal and rock mass were defined in this study. In addition, this paper studied the symbiotic disaster prevention and control mechanism, and technical change in cross-scale fractures field flow distribution, through the rational elimination of gas and coal spontaneous combustion symbiotic disaster, that is, the symbiotic region was equal to 0. The authors also proposed two new control technologies, which are: to change coal- rock fractures leakscale through solid-phase media transport, and to change the goaf temperature field and the gas concentration field through low-temperature liquid inert gas seepage. A network graph theoretical model of a particle transport of fine solid phases to change coal-rock fractures scale had been developed in this study, which reveals that solid phase media can be embedded.in the pneumatic transport blocking air leakage in the coal-rock fractureds field, to reduce air leakage fractures scale and the effective fissure numbers, and change the scale of coal-rock fractures leak field, as well as to increase air leakage resistance to ensure the safety of coal spontaneous combustion for high gas extraction. Also, the authors built an experimental simulation platform for investigating liquid nitrogen extinguishing characteristics, and the results show that the liquid nitrogen injected into the fire area can quickly cause heat expansion, resulting in a large number of low-temperature nitrogen pockets in the goaf, forming a three-dimensional buffer zone to reduce the external air leakage into the goaf or fire zone, to isolate the goaf or fire area. At the same time, the low-temperature nitrogen gas carries water vapor condensation into the goaf, exchanging heat with hidden heat source ( fire source), which can reduce the temperature of the heat (fire source) to below the temperature of flammable point and actively engulf the heat source (fire source). [ABSTRACT FROM AUTHOR]

While the gas drainage efficiency has attracted much attention, the importance of safe drainage should be recognized. Under the effect of gas drainage, air flows into the drainage borehole through fractures, providing sufficient oxygen for coal spontaneous combustion and making gas drainage concentration decline into the explosion scope. Based on the risk of coal spontaneous combustion induced by gas drainage and gas explosion in the drainage pipe, the concept of safe drainage was proposed, and the safety factor was defined to quantitatively evaluate the security of gas drainage. By establishing the seepage and diffusion of multicomponent gas, coal-oxygen reaction and heat transfer equations and analyzing the evolution of multicomponent gas flow, oxygen concentration and temperature field, the theoretical model for safe drainage of coal seam gas was built. Taking gas drainage project in Shanjiaoshu Mine of Panjiang Coal and Electricity Group as example, the influence of negative pressure, sealing quality, permeability of distressed zone, gas absorption speciality and coal spontaneous combustion characteristics on safety factor of gas drainage were studied, and some technical measures to ensure the safe drainage were given. [ABSTRACT FROM AUTHOR]

Based on four-stage Stackelberg dynamic game analysis, this paper constructs products quality control model of distribution channel in three-echelon supply chain which is composed by one manufacturer, two retailers and the final customers, and studies how to make products quality control decision and design distribution channel strategy with R&D motivation. We develop three types of distribution channel strategy model (direct channel strategy, indirect channel strategy and mixed channel strategy), and analyze the distribution channel strategy with R&D motivation how to influence manufacturer's products quality decision, retailer's products purchase decision, expected profits function and the customer's consumer surplus. Our paper will demonstrate that: when there exists R&D motivation, products quality level, wholesales price and retailing price will increase, the manufacturer's profits will decrease, the retailer's profits and the customer's consumer surplus will increase; when the manufacturer chooses indirect channel strategy, the products quality level and retailing price will reduce, the customer's consumer surplus will also decrease; when the manufacturer who chooses low products quality takes indirect channel strategy, the customer's consumer surplus will increase; when the manufacturer who chooses high products quality takes indirect channel strategy, the customer's consumer surplus will be lowest, our conclusions will be a strong complement in the research field. Above all, we conduct an example analysis, the numerical computing results prove the model's effective and conclusion's corrective, which will indicate the further specific application direction in practice. [ABSTRACT FROM AUTHOR]

Improving the green development efficiency of the three major urban agglomerations in Zhejiang is an important way to faster build the pilot demonstration area of beautiful China. Based on county panel data from 2000 to 2019 of 41 counties (cities) included in the three major urban agglomerations, we combined the super-efficiency SBM model with window analysis to evaluate the efficiency, and used spatial econometric analysis method to study the spatial distribution and the differences in regional difference. Furthermore, the fixed panel fixed effect model was used to explore the differential influencing mechanism. The results showed that green development efficiency of the three major urban agglomerations increased gradually with fluctuations during the study period. The distribution of efficiency values gradually shifted from a situation of 'high in the north and low in the south' to a 'relatively common and coordinated' development in the various regions. There was a significant spatial agglomeration effect in green development efficiency of the three major urban agglomerations, but it presented fluctuating phenomenon among cities which were at the similar level. The average green development efficiency of central Zhejiang urban agglomeration was the highest. The development within the three major urban agglomerations was relatively stable. The annulus Hangzhou Bay urban agglomeration came next, with stable development. The Wenzhou-Taizhou coastal urban agglomeration was the lowest, but the efficiency enhancement was the largest. The increases in population density, along with the proportion of added value of tertiary industry in GDP, per capita industrial added value, local fiscal expenditures, education expenditures and per capita actual use of foreign capital could improve the efficiency of green development. However, the increases in industrial electricity consumption and fixed asset investment in kennels would inhibit the improvement of green development efficiency. The impacts of per capita industrial added value, local fiscal expenditure, education expenditure and per capita actual use of foreign capital on urban agglomerations were heterogeneous among different cities.

Objective: To investigate the morbidity and pathological features of incidental prostate cancer and their clinical significance., Methods: 1483 prostate specimens obtained during operation, including transurethral resection of prostate (TURP) and total resection of the prostate, for the diagnoses of benign prostatic hypertrophy (BPH) or bladder cancer between January 1999 and August 2005 underwent pathological examination and 34beta12 and p63 immunohistochemical staining so as to detect incidental prostate cancer. The volume of incidental prostate cancer was calculated by the image analysis system. The clinical data were analyzed retrospectively. Comparison between the clinical and pathological feature of incidental prostate cancer was made., Results: 53 cases of incidental prostate cancer, with the Gleason scores from 2 (1+1) to 9 (4+5) and the volumes from 0.18 to 1440.00 mm(3) were detected. The morbidity of incidental prostate cancer was 3.6%. The volume of 47 cases (88.7%) were less than 0.5 cm(3) as the threshold of insignificant cancer, and the volumes of 6 cases (11.3%) were more than 0.5 cm(3). All incidental prostate cancers of clinical significance were detected in the TURP samples. Among the incidental prostate cancers found in the TURP samples 20% were clinically significant cancers. The clinically significant incidental cancers were located in the central or transitional zone with the Gleason scores of 3 + 4 (2 cases), 4 + 2 (1 case), or 4 + 5 (3 cases). These clinically significant cancers were of diffuse distribution, and their preoperative clinical features were negative in palpation/image examination, elevation of serum PSA, and negative in puncture examination., Conclusion: Nowadays, the morbidity of incidental prostate cancer is lower than that of 1980s'. Among the incidental cancers 11.3% were of clinical significance. That the preoperative clinical examination cannot find these clinical significant cancers is partially caused by the pathological features of these tumors.

Objective: To summarize the experience of ultrasound guided percutaneous aspiration and sclerotherapy for peripelvic cysts and investigate the clinical effect., Methods: A total of 169 cases of peripelvic cyst patients were evaluated, of whom 36 cases (21.3%) had hydronephrosis secondary to peripelvic cysts, 8 cases (4.7%) had renal calculus. All patients underwent ultrasound and intravenous phelography (IVP) examination, 59 patients also had CT scan. Hydatid fluid was analyzed by amine test. Percutaneous aspiration was guided by ultrasound, 95% alcohol was used to sclerosis the peripelvic cysts when amine test was negative or positive but did not have communication with pelvis through opacification. Ultrasound were done at 1, 3, 6 months and every 1 year thereafter, follow-up period were 6 months to 5 years., Results: One hundred and sixty-five peripelvic cysts (97.6%) were cured by once sclerotherapy, the diameter of another 4 cases (2.4%) diminished to less than 1.5 cm by once sclerotherapy. Thirty-six cases of hydronephrosis were all resolved after sclerotherapy. Eight cases had renal calculus, of whom 4 cases underwent extracorporeal shockwave lithotripsy, 2 cases underwent percutaneous nephrolithotomy, and 2 cases did not treat the stone. Five patients had gross hematuria after aspiration, but all diminished in 3-5 d., Conclusion: Ultrasound guided percutaneous aspiration and sclerotherapy for peripelvic cysts had the superiority of safety, effectiveness micro-invasion and low complication.

Objective: To investigate the prognostic value of some clinicopathologic indexes and biologic tumor markers in predicting recurrence in T1 transitional cell carcinoma (TCC) of the bladder., Methods: The expressions of p53, E-cadherin and VEGF of 75 patients with T1 primary bladder TCC were detected by streptabitin peroxidase (SP) immunohistochemical methods. The effects of clinicopathologic indexes and biologic tumor markers on recurrence were assessed by Kaplan-Meier and Cox proportional hazards model., Results: The 1-, 3-, and 5-year recurrence- free survival rates were 68.0%, 45.3% and 20.9%. In Kaplan-Meier analysis, tumor mutifocality and the expression of p53, E-cadherin and VEGF were associated with recurrence. In multivariate analysis, the independent recurrence variables were tumor mutifocality, the expression of p53 and E-cadherin., Conclusion: Tumor mutifocality and the abnormal expression of p53 and E-cadherin are the variables that independently predict recurrence in T1 transitional cell carcinoma of the bladder.