Taking a microwave product as an example, a system of integrated assembly structure design is presented. Getting design constraints from the upstream design section through product data management(PDM), the system gen...Taking a microwave product as an example, a system of integrated assembly structure design is presented. Getting design constraints from the upstream design section through product data management(PDM), the system generates the assembly scheme using the case? based method, then assigns the design requirements into each component of the assembly. The detail design for each component can be performed under these design constraints. In order to practise concurrent design, the system sends the final design result to the upstream section and downstream section through PDM to achieve information sharing and integration.展开更多
The primary school system in Mexico is affected by serious shortfalls in the installation of related information and communication technologies resources in the teaching-learning process. This lack of resources has an...The primary school system in Mexico is affected by serious shortfalls in the installation of related information and communication technologies resources in the teaching-learning process. This lack of resources has an impact of the context of the digital divide as well as in joining the knowledge society. The present article will deal with the outfitting of classrooms with the enciclomedia system in the 5tb and 6th grade in the State of Puebla. It will demonstrate important findings, demonstrating the deepening digital divide between the state capital and the rest of the municipalities in this state. In fact, the furthest (300 km far away from Puebla city) the less primary school equipped with the enciclomedia system. We will also demonstrate the resource distribution by school-type and inhabitants. Another finding is the influence in resource distribution by political party. This study should provide public policy decision-makers with valuable information for the apportionment of resources in all municipalities of the State of Puebla.展开更多
Various proportional and nonproportional tension-torsion fatigue tests are conducted on aeronautical material-LY12CZ aluminum alloy. The stress and strain states under tension-torsion loading are analyzed by an elasti...Various proportional and nonproportional tension-torsion fatigue tests are conducted on aeronautical material-LY12CZ aluminum alloy. The stress and strain states under tension-torsion loading are analyzed by an elastic-plastic finite element method. The relation between the orientation of crack propagation and each stress and strain component is investigated. Analytical results are compared with experimental data. Results demonstrate that the fatigue cracks tend to be propagated perpendicular to the direction of the largest principle strains under proportional loading, and grow alone one of the maximum shear strain planes under 45° and 90° out-of-phase loadings.展开更多
Many studies have qualitatively explained that information and communication technology(ICT) has loosened the restrictions of distance and space on retailers' sales. Few empirical studies, however, have explored t...Many studies have qualitatively explained that information and communication technology(ICT) has loosened the restrictions of distance and space on retailers' sales. Few empirical studies, however, have explored the impact of shipping distance on online retailers' sales. This study examined the Maiyang(M-Y) store on Tmall in China as a case study to investigate the relationship between shipping distance and sales. The results showed that sales volume in 2014 at the county level did not strictly obey the distance decay law. The shipped distance of high-priced commodities may not be much longer than that of low-priced commodities. Within the scope of investigation, the relationships between income, cost, and net profit curves do not follow central place theory. Goods have neither thresholds nor ranges. The key factor in the spatial discrepancy of sales is the size of market. The impact of shipping distance on sales is not as strong as that of traditional retailers in Information Era.展开更多
The scientific software installation testing has a main goal: Evaluate if the software meets its requirements and specifications. In this paper, the scientific software installation in six machines is evaluated. The ...The scientific software installation testing has a main goal: Evaluate if the software meets its requirements and specifications. In this paper, the scientific software installation in six machines is evaluated. The software installation was tested using a PDCA (Plan-Do-Check-Act) approach in 3 machines and were compared with other 3 machines which were installed exclusively based in the installer experience. The software installed on the machines using a PDCA approach for testing, lead to the expected results. Scientific software installation should be tested during the installation and not as a final test. A methodology based on PDCA is recommended for testing scientific software.展开更多
To understand the combustion characteristics of potassium nitrate and evaluate the magnitude of combustion risk, ox-idation solid test apparatus is used and the updated experimental criterion of the United Nations is...To understand the combustion characteristics of potassium nitrate and evaluate the magnitude of combustion risk, ox-idation solid test apparatus is used and the updated experimental criterion of the United Nations is adopted to measure the pack-aging category of potassium nitrate. The new criterion puts calcium peroxide and microcrystalline cellulose as references and burning rate as evaluation index. Effects of mixing ratio and insert medium on burning rate are reached. Test results show that pure potassium nitrate doesn't burn under normal temperature and pressure, however, its oxidation is very strong and the packaging category should choose the class I. As the mass fraction of potassium nitrate reduces, the burning rate first increases and then decreases. When the ratio is 2 : 1,the combustion rate reaches the maximum, and the effect of combustion is the best. When 1 : 3, the combustion rate is the minimum. The mixture combustion can be suppressed by silicon dioxide and hy-drogen phosphate, which is not fired when silica concentration is 40% or ammonium hydrogen potassium phosphate is 55%, their effects are very obvious.展开更多
In this paper, multi-refinery using the same heavy crude oils as raw materials is studied, while a new nonlinear model for mixed heavy crude distillation is proposed. In practical crude distillation operation, the dis...In this paper, multi-refinery using the same heavy crude oils as raw materials is studied, while a new nonlinear model for mixed heavy crude distillation is proposed. In practical crude distillation operation, the distillate yield and product distribution of distillation units are different due to their various equipment and operating parameters, even the same ratio of raw materials is provided, so different process models for multi-refinery planning is therefore required. For process modeling, the relationships between total yields and mixing ratio of different refineries were determined, which is combined with process simulation using production data. Then,the yields and properties of crude distillation unit(CDU) fractions were calculated with the use of true boiling point(TBP) curves and property curves respectively when the initial cutting temperatures were given. Finally,in order to maximize the economic benefit of distillation, the optimal product distribution and the best mixing ratio of crude oil were calculated under the constraints of different properties of fractions. Comparing to previous models, the proposed model takes the influence of different refinery parameters on production process into account, while avoiding the complex process for determining the cutting points, which is considered more efficient and more accurate with respect to heavy crude refinery. Model was successfully verified by a case study,allowing a significant improvement of the refinery profit to be achieved.展开更多
This paper deals with the problem of accelerometer error estimation and compensation for a three-axis gyro-stabilized camera mount. In a dynamic environment, the aircraft motion acceleration affects the accelerome :e...This paper deals with the problem of accelerometer error estimation and compensation for a three-axis gyro-stabilized camera mount. In a dynamic environment, the aircraft motion acceleration affects the accelerome :er output and causes a degradation of attitude steady accuracy. In order to improve control accuracy, this paper proposes a proportional multiple-integral observer- based control strategy to estimate and compensate the accelerometer error. The basic idea of this paper is to approximate the error property by using a q-order polynomial function and extend the error and its derivatives as augmented states. Then a proportional multiple-integral observer is developed to estimate the error, with which the relationship between the error and the imbalance torque is formulated. The estimated value is compared to an angle threshold, the result of which is used to compen- sate the accelerometer output. Through static and vehicle-mounted experiments, it is demonstrated that compared with the tra- ditional method, the proposed method can improve the attitude steady accuracy effectively.展开更多
The management of blunt renal trauma has been evolving. The past management largely based on American Association for Surgery of Trauma (AAST) grading system, i.e. necessitated a computed tomography (CT) scan. Alt...The management of blunt renal trauma has been evolving. The past management largely based on American Association for Surgery of Trauma (AAST) grading system, i.e. necessitated a computed tomography (CT) scan. Although the CT scan use is increasing and becomes the standardized mode of investigation, AAST grading no longer plays the sole role in the decision of surgical interventions. Two case reports of blunt renal trauma managed successfully by conservative methods are presented. Case one was an 18 year-old boy who had a fall when riding a motorbike at 20 km/h with a helmet and full protective equipments. He was landed by his left flank onto a rock. Contrast abdominal CT revealed a 4 era, grade III splenic tear and a grade IV left kidney injury with large perirenal haematoma. His international severity score (ISS) was 34. He was managed conservatively with bed rest and frequent serum haemoglobin monitoring. Subsequent CT with delayed contrast revealed stable perirenal haematoma with urine extravasation which was consistent with a grade IV renal injury. Case two was a 40 year-old male who had a motor bike accident on a racetrack when he was driving at 80 to 100 km/h, wearing a helmet. He lost control and hit onto the sidewall of the racetrack. Contrast abdominal CT revealed a grade IV left renal injury with a large urine extravasation. His renal injury was managed conservatively with interval delayed phase CT of the abdomen. A repeat CT on abdomen was performed five months after the initial injury which revealed no residual urinoma. In this study, moreover, a review of the literature to the management of blunt renal trauma was conducted to demonstrate the trend of increasing conservative management of such traumas. Extra radiological parameters may guide future decision making. However, the applicability of data may be limited until randomized trials are available.展开更多
文摘Taking a microwave product as an example, a system of integrated assembly structure design is presented. Getting design constraints from the upstream design section through product data management(PDM), the system generates the assembly scheme using the case? based method, then assigns the design requirements into each component of the assembly. The detail design for each component can be performed under these design constraints. In order to practise concurrent design, the system sends the final design result to the upstream section and downstream section through PDM to achieve information sharing and integration.
文摘The primary school system in Mexico is affected by serious shortfalls in the installation of related information and communication technologies resources in the teaching-learning process. This lack of resources has an impact of the context of the digital divide as well as in joining the knowledge society. The present article will deal with the outfitting of classrooms with the enciclomedia system in the 5tb and 6th grade in the State of Puebla. It will demonstrate important findings, demonstrating the deepening digital divide between the state capital and the rest of the municipalities in this state. In fact, the furthest (300 km far away from Puebla city) the less primary school equipped with the enciclomedia system. We will also demonstrate the resource distribution by school-type and inhabitants. Another finding is the influence in resource distribution by political party. This study should provide public policy decision-makers with valuable information for the apportionment of resources in all municipalities of the State of Puebla.
文摘Various proportional and nonproportional tension-torsion fatigue tests are conducted on aeronautical material-LY12CZ aluminum alloy. The stress and strain states under tension-torsion loading are analyzed by an elastic-plastic finite element method. The relation between the orientation of crack propagation and each stress and strain component is investigated. Analytical results are compared with experimental data. Results demonstrate that the fatigue cracks tend to be propagated perpendicular to the direction of the largest principle strains under proportional loading, and grow alone one of the maximum shear strain planes under 45° and 90° out-of-phase loadings.
基金Under the auspices of the National Planning Office of Philosophy and Social Science(No.17BRK010)National Natural Science Foundation of China(No.41601161)+1 种基金Natural Science Foundation of Guangdong Province(No.2017A030313224)Guangdong Planning Office of Philosophy and Social Science(No.2017GZZK16)
文摘Many studies have qualitatively explained that information and communication technology(ICT) has loosened the restrictions of distance and space on retailers' sales. Few empirical studies, however, have explored the impact of shipping distance on online retailers' sales. This study examined the Maiyang(M-Y) store on Tmall in China as a case study to investigate the relationship between shipping distance and sales. The results showed that sales volume in 2014 at the county level did not strictly obey the distance decay law. The shipped distance of high-priced commodities may not be much longer than that of low-priced commodities. Within the scope of investigation, the relationships between income, cost, and net profit curves do not follow central place theory. Goods have neither thresholds nor ranges. The key factor in the spatial discrepancy of sales is the size of market. The impact of shipping distance on sales is not as strong as that of traditional retailers in Information Era.
文摘The scientific software installation testing has a main goal: Evaluate if the software meets its requirements and specifications. In this paper, the scientific software installation in six machines is evaluated. The software installation was tested using a PDCA (Plan-Do-Check-Act) approach in 3 machines and were compared with other 3 machines which were installed exclusively based in the installer experience. The software installed on the machines using a PDCA approach for testing, lead to the expected results. Scientific software installation should be tested during the installation and not as a final test. A methodology based on PDCA is recommended for testing scientific software.
基金Major Research and Development Project of Shanxi Province(No.201603D121012)
文摘To understand the combustion characteristics of potassium nitrate and evaluate the magnitude of combustion risk, ox-idation solid test apparatus is used and the updated experimental criterion of the United Nations is adopted to measure the pack-aging category of potassium nitrate. The new criterion puts calcium peroxide and microcrystalline cellulose as references and burning rate as evaluation index. Effects of mixing ratio and insert medium on burning rate are reached. Test results show that pure potassium nitrate doesn't burn under normal temperature and pressure, however, its oxidation is very strong and the packaging category should choose the class I. As the mass fraction of potassium nitrate reduces, the burning rate first increases and then decreases. When the ratio is 2 : 1,the combustion rate reaches the maximum, and the effect of combustion is the best. When 1 : 3, the combustion rate is the minimum. The mixture combustion can be suppressed by silicon dioxide and hy-drogen phosphate, which is not fired when silica concentration is 40% or ammonium hydrogen potassium phosphate is 55%, their effects are very obvious.
文摘In this paper, multi-refinery using the same heavy crude oils as raw materials is studied, while a new nonlinear model for mixed heavy crude distillation is proposed. In practical crude distillation operation, the distillate yield and product distribution of distillation units are different due to their various equipment and operating parameters, even the same ratio of raw materials is provided, so different process models for multi-refinery planning is therefore required. For process modeling, the relationships between total yields and mixing ratio of different refineries were determined, which is combined with process simulation using production data. Then,the yields and properties of crude distillation unit(CDU) fractions were calculated with the use of true boiling point(TBP) curves and property curves respectively when the initial cutting temperatures were given. Finally,in order to maximize the economic benefit of distillation, the optimal product distribution and the best mixing ratio of crude oil were calculated under the constraints of different properties of fractions. Comparing to previous models, the proposed model takes the influence of different refinery parameters on production process into account, while avoiding the complex process for determining the cutting points, which is considered more efficient and more accurate with respect to heavy crude refinery. Model was successfully verified by a case study,allowing a significant improvement of the refinery profit to be achieved.
基金supported by the National Natural Science Foundation of China(Grant Nos.61174121,61333005 and 61121003)the Ph.D Programs Foundations of the Ministry of Education China
文摘This paper deals with the problem of accelerometer error estimation and compensation for a three-axis gyro-stabilized camera mount. In a dynamic environment, the aircraft motion acceleration affects the accelerome :er output and causes a degradation of attitude steady accuracy. In order to improve control accuracy, this paper proposes a proportional multiple-integral observer- based control strategy to estimate and compensate the accelerometer error. The basic idea of this paper is to approximate the error property by using a q-order polynomial function and extend the error and its derivatives as augmented states. Then a proportional multiple-integral observer is developed to estimate the error, with which the relationship between the error and the imbalance torque is formulated. The estimated value is compared to an angle threshold, the result of which is used to compen- sate the accelerometer output. Through static and vehicle-mounted experiments, it is demonstrated that compared with the tra- ditional method, the proposed method can improve the attitude steady accuracy effectively.
文摘The management of blunt renal trauma has been evolving. The past management largely based on American Association for Surgery of Trauma (AAST) grading system, i.e. necessitated a computed tomography (CT) scan. Although the CT scan use is increasing and becomes the standardized mode of investigation, AAST grading no longer plays the sole role in the decision of surgical interventions. Two case reports of blunt renal trauma managed successfully by conservative methods are presented. Case one was an 18 year-old boy who had a fall when riding a motorbike at 20 km/h with a helmet and full protective equipments. He was landed by his left flank onto a rock. Contrast abdominal CT revealed a 4 era, grade III splenic tear and a grade IV left kidney injury with large perirenal haematoma. His international severity score (ISS) was 34. He was managed conservatively with bed rest and frequent serum haemoglobin monitoring. Subsequent CT with delayed contrast revealed stable perirenal haematoma with urine extravasation which was consistent with a grade IV renal injury. Case two was a 40 year-old male who had a motor bike accident on a racetrack when he was driving at 80 to 100 km/h, wearing a helmet. He lost control and hit onto the sidewall of the racetrack. Contrast abdominal CT revealed a grade IV left renal injury with a large urine extravasation. His renal injury was managed conservatively with interval delayed phase CT of the abdomen. A repeat CT on abdomen was performed five months after the initial injury which revealed no residual urinoma. In this study, moreover, a review of the literature to the management of blunt renal trauma was conducted to demonstrate the trend of increasing conservative management of such traumas. Extra radiological parameters may guide future decision making. However, the applicability of data may be limited until randomized trials are available.