BACKGROUND Pulse oximetry has become a cornerstone technology in healthcare,providing non-invasive monitoring of oxygen saturation levels and pulse rate.Despite its widespread use,the technology has inherent limitatio...BACKGROUND Pulse oximetry has become a cornerstone technology in healthcare,providing non-invasive monitoring of oxygen saturation levels and pulse rate.Despite its widespread use,the technology has inherent limitations and challenges that must be addressed to ensure accurate and reliable patient care.AIM To comprehensively evaluate the advantages,limitations,and challenges of pulse oximetry in clinical practice,as well as to propose recommendations for optimizing its use.METHODS A systematic literature review was conducted to identify studies related to pulse oximetry and its applications in various clinical settings.Relevant articles were selected based on predefined inclusion and exclusion criteria,and data were synthesized to provide a comprehensive overview of the topic.RESULTS Pulse oximetry offers numerous advantages,including non-invasiveness,real-time feedback,portability,and costeffectiveness.However,several limitations and challenges were identified,including motion artifacts,poor peripheral perfusion,ambient light interference,and patient-specific factors such as skin pigmentation and hemoglobin variants.Recommendations for optimizing pulse oximetry use include technological advancements,education and training initiatives,quality assurance protocols,and interdisciplinary collaboration.CONCLUSION Pulse oximetry is crucial in modern healthcare,offering invaluable insights into patients’oxygenation status.Despite its limitations,pulse oximetry remains an indispensable tool for monitoring patients in diverse clinical settings.By implementing the recommendations outlined in this review,healthcare providers can enhance the effectiveness,accessibility,and safety of pulse oximetry monitoring,ultimately improving patient outcomes and quality of care.展开更多
With the rapid development of big data,cloud computing,artificial intelligence,and other technologies,digital construction has gradually become a crucial means of enterprise development,significantly impacting the ope...With the rapid development of big data,cloud computing,artificial intelligence,and other technologies,digital construction has gradually become a crucial means of enterprise development,significantly impacting the operation and management activities of enterprises.Outward Foreign Direct Investment(OFDI)is one of the key pathways for Chinese enterprises to“go global,”contributing to improved economic efficiency and promoting national economic development.Therefore,studying the advantages of digitalization in OFDI activities will aid in exploring effective methods for Chinese enterprises to engage in OFDI within the digital economy and provide an important foundation for strategic enterprise planning and national policy formulation.This paper combines the current state of OFDI among Chinese enterprises,analyzes the advantages and roles of digital construction in OFDI,and explores relevant countermeasures,aiming to provide theoretical references for enterprises’OFDI activities in the context of digitalization.展开更多
Objective:To evaluate the clinical advantages of laparoscopic transverse abdominal wall suspension in treating pelvic organ prolapse.Methods:Sixty patients diagnosed with moderate to severe pelvic organ prolapse and u...Objective:To evaluate the clinical advantages of laparoscopic transverse abdominal wall suspension in treating pelvic organ prolapse.Methods:Sixty patients diagnosed with moderate to severe pelvic organ prolapse and underwent surgical treatment in our hospital between January 2022 and December 2023 were selected.According to different surgical methods,they were divided into an observation group(given laparoscopic transverse abdominal wall suspension)and a control group(given transvaginal mesh implantation),with 30 subjects/group.The data on perioperative-related indicators,quality of life scores,postoperative recurrence,and complications of the two groups of patients were collected.Results:The postoperative hospitalization days and intraoperative bleeding volume of the observation group were significantly lower than those of the control group,but had longer operation time than that of the control group(P<0.05).The differences between the two groups were statistically significant 6 months after surgery,and the Pelvic Floor Disease Quality of Life Impact Questionnaire(PFIQ-7)score of the observation group was significantly higher than the control group(P<0.05).Both groups of patients completed 12 months of follow-up without any postoperative recurrence.The number of complications in the observation group was slightly lower than that of the control group(P>0.05).Conclusion:Laparoscopic transverse abdominal wall suspension was more effective in treating pelvic organ prolapse and is an ideal surgical procedure.展开更多
The concept of rural tourist resources was introduced to analyze the present rural tourism development in Shaanxi Province,tourist resources in its rural areas were investigated comprehensively,structures,quantity and...The concept of rural tourist resources was introduced to analyze the present rural tourism development in Shaanxi Province,tourist resources in its rural areas were investigated comprehensively,structures,quantity and quality of 7 major types of both natural and cultural tourist resources were evaluated,and resource combinations were also analyzed from the perspective of geological location.Characteristics and advantages of rural tourist resources in Shaanxi Province were summarized as "abundant,diversified and high-quality";rural cultural tourist resources took the Absolute predominance and had great development potentials;cultural tourist resources such as folk cultures had distinctive regional features;rural natural tourist resources had obvious regional characteristics;resources were reasonably combined,each resource region had its own features.This study aimed at providing scientific support for the development,planning and protection of rural tourist resources in Shaanxi Province.展开更多
[Objective]This study aimed to clarify the spatial patterns of comparative advantage of watermelon production in Guangxi Zhuang Autonomous Region, to pro-vide theoretical basis for the development of watermelon indust...[Objective]This study aimed to clarify the spatial patterns of comparative advantage of watermelon production in Guangxi Zhuang Autonomous Region, to pro-vide theoretical basis for the development of watermelon industry in China. [Method] Based on the agricultural statistics data of Guangxi and al over China, yield com-parative advantage (YCA) index, efficiency comparative advantage (ECA) index, scale comparative advantage (SCA) index, concentration ratio comparative advantage (CRCA) index, comprehensive comparative advantage (CCA) index, ratio of yield per unit area (RYPA) index and sowing area ratio (SAR) index were established and calculated to determine the watermelon production comparative advantages in 31 provinces (cities) in China. Spacial patterns of the comparative advantages were produced by using GIS software. [Result] Nine provinces Shandong, Henan, Anhui, Hebei, Hubei, Jiangsu, Hunan, Zhejiang and Guangxi were the dominant regions in watermelon production al over the country. The Central and Eastern China showed the integrated comparative advantage in watermelon production, while the Southern, Northeastern, Northern and Northwestern China can be considered as the potential places for watermelon production in future. Southwest China gave more priority to watermelon production, so the comparative advantages kept increasing here. [Con-clusion] Based on this study, watermelon production should be a prior consideration among the agricultural products in Guangxi. Related measures should be developed to optimize the regional distribution of watermelon in Guangxi and China to promote healthy competition in watermelon production.展开更多
In English teachinig,the use of multi-media makes a vivid learning atmosphere for students.It can get a better teaching effect in all-around education.Meanwhile,thereare some problems inevitably in this field,leaving ...In English teachinig,the use of multi-media makes a vivid learning atmosphere for students.It can get a better teaching effect in all-around education.Meanwhile,thereare some problems inevitably in this field,leaving for the English teachers to solve.展开更多
With the world globalization, China's communication with other countries has become more frequent. It is in great demand that a large number of college graduates who not only master their major but also do well in...With the world globalization, China's communication with other countries has become more frequent. It is in great demand that a large number of college graduates who not only master their major but also do well in communication in English with English speakers. However, such graduates are scare because the backward teaching method-the Grammar-Traditional Method, cannot meet what the contemporary Chinese society demands. The reforms of the college English teaching are urgent and necessary. This paper first explores the major problems existing in the college English teaching. Furthermore, it introduces the basic theory of the Communicative Approach and analyzes its advantages in college English teaching.展开更多
Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which...Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM.展开更多
In this study, forced nonlinear vibration of a circular micro-plate under two-sided electrostatic, two-sided Casimir and external harmonic forces is investigated analytically. For this purpose, at first, von Karman pl...In this study, forced nonlinear vibration of a circular micro-plate under two-sided electrostatic, two-sided Casimir and external harmonic forces is investigated analytically. For this purpose, at first, von Karman plate theory including geometrical nonlinearity is used to obtain the deflection of the micro-plate. Galerkin decomposition method is then employed, and nonlinear ordinary differential equations (ODEs) of motion are determined. A harmonic balance method (HBM) is applied to equations and analytical relation for nonlineaT frequency response (F-R) curves are derived for two categories (including and neglecting Casimir force) separately. The analytical results for three cases:(1) semi-linear vibration;(2) weakly nonlinear vibration;(3) highly non linear vibration, are validated by comparing with the numerical solutio ns. After validation, the effects of the voltage and Casimir force on the natural frequency of two-sided capacitor system are investigated. It is shown that by assuming Casimir force in small gap distances, reduction of the natural frequency is considerable. The influences of the applied voltage, damping, micro-plate thickness and Casimir force on the frequency response curves have been presented too. The results of this study can be useful for modeling circular parallel-plates in nano /microelectromechanical transducers such as microphones and pressure sensors.展开更多
Due to the NP-hardness of the two-sided assembly line balancing (TALB) problem, multiple constraints existing in real applications are less studied, especially when one task is involved with several constraints. In ...Due to the NP-hardness of the two-sided assembly line balancing (TALB) problem, multiple constraints existing in real applications are less studied, especially when one task is involved with several constraints. In this paper, an effective hybrid algorithm is proposed to address the TALB problem with multiple constraints (TALB-MC). Considering the discrete attribute of TALB-MC and the continuous attribute of the standard teaching-learning-based optimization (TLBO) algorithm, the random-keys method is hired in task permutation representation, for the purpose of bridging the gap between them. Subsequently, a special mechanism for handling multiple constraints is developed. In the mechanism, the directions constraint of each task is ensured by the direction check and adjustment. The zoning constraints and the synchronism constraints are satisfied by teasing out the hidden correlations among constraints. The positional constraint is allowed to be violated to some extent in decoding and punished in cost fimction. Finally, with the TLBO seeking for the global optimum, the variable neighborhood search (VNS) is further hybridized to extend the local search space. The experimental results show that the proposed hybrid algorithm outperforms the late acceptance hill-climbing algorithm (LAHC) for TALB-MC in most cases, especially for large-size problems with multiple constraints, and demonstrates well balance between the exploration and the exploitation. This research proposes an effective and efficient algorithm for solving TALB-MC problem by hybridizing the TLBO and VNS.展开更多
The phenomena of TL are connected with the defect structures of the atomic lattice of the material concerned, and hence are very sensitive to changes in defection of the country rocks status as induced by the minerali...The phenomena of TL are connected with the defect structures of the atomic lattice of the material concerned, and hence are very sensitive to changes in defection of the country rocks status as induced by the mineralizing solution. In other words, the TL of the country rocks from the mineralized area should be quite different from that in the intact barren area.Besides the high sensitivity as mentioned above, advantages of the application of TL techniques to the mineral exploration the easiness in accessing to proper samples, the easy preparation of samples and the quickness in sample processing all amount to convenience and economy of the techniques, indicating the high competitiveness of the TL mineral exploration method, especially during the development stage of mining operations.展开更多
The development of information technology has changed people's learning methods. Fragmented learning,as an informal learning method,has become an important way to accept new knowledge and learn new technologies. T...The development of information technology has changed people's learning methods. Fragmented learning,as an informal learning method,has become an important way to accept new knowledge and learn new technologies. Through analyzing the connotation,characteristics,and advantages and disadvantages of fragmented learning,this paper came up with reasonable recommendations for fragmented learning. To truly become systematic and holistic knowledge,fragmented knowledge must be explored,understood,integrated and internalized. This paper is expected to play an important guiding role in building a lifelong learning society.展开更多
A two-sided assembly line is typically found in plants producing large-sized products. Its advantages over a one-sided line and the difficulties faced in two-sided line balancing problems were discussed. A mathematica...A two-sided assembly line is typically found in plants producing large-sized products. Its advantages over a one-sided line and the difficulties faced in two-sided line balancing problems were discussed. A mathematical model for two-ALB problem was suggested. A modification of the “ranked positional weight” method, namely two-ALB RPW for two-ALB problems was developed. Experiments were carried out to verify the performance of the proposed method and the results show that it is effective in solving two-sided assembly line balancing problems.展开更多
企业竞争优势依赖于其所生存的环境,金融危机爆发之后的经济下行使装备制造企业竞争优势的来源发生了根本性的改变.通过对辽宁9 家企业的问卷调查,探究了辽宁装备制造企业的竞争优势现状,厘清了竞争优势维度对财务绩效的不同作用,进一...企业竞争优势依赖于其所生存的环境,金融危机爆发之后的经济下行使装备制造企业竞争优势的来源发生了根本性的改变.通过对辽宁9 家企业的问卷调查,探究了辽宁装备制造企业的竞争优势现状,厘清了竞争优势维度对财务绩效的不同作用,进一步研究了竞争优势的提升路径.研究表明:经济下行对企业竞争优势的影响较大;目前竞争优势主要来源于低成本优势和新产品研发优势,但近年来新产品研发得到了较快的发展,而成本优势正在大幅减弱;产品开发、技术资源、软件和市场份额对总资产报酬率影响较大,而成本、与用户信任程度关系、质量和Y R IN技术资源对销售利润率影响较大;产品开发、成本、服务、与用户信任程度和性能是企业需要关注的重点.展开更多
Intercropping of maize(Zea mays L.) and peanut(Arachis hypogaea L.) often results in greater yields than the respective sole crops. However, there is limited knowledge of aboveground and belowground interspecific inte...Intercropping of maize(Zea mays L.) and peanut(Arachis hypogaea L.) often results in greater yields than the respective sole crops. However, there is limited knowledge of aboveground and belowground interspecific interactions between maize and peanut in field. A two-year field experiment was conducted to investigate the effects of interspecific interactions on plant growth and grain yield for a peanut/maize intercropping system under different nitrogen(N) and phosphorus(P) levels. The method of root separation was employed to differentiate belowground from aboveground interspecific interactions. We observed that the global interspecific interaction effect on the shoot biomass of the intercropping system decreased with the coexistence period, and belowground interaction contributed more than aboveground interaction to advantages of the intercropping in terms of shoot biomass and grain yield. There was a positive effect from aboveground and belowground interspecific interactions on crop plant growth in the intercropping system, except that aboveground interaction had a negative effect on peanut during the late coexistence period. The advantage of intercropping on grain came mainly from increased maize yield(means 95%) due to aboveground interspecific competition for light and belowground interaction(61%–72% vs. 28%–39% in fertilizer treatments). There was a negative effect on grain yield from aboveground interaction for peanut, but belowground interspecific interaction positively affected peanut grain yield.The supply of N, P, or N + P increased grain yield of intercropped maize and the contribution from aboveground interspecific interaction. Our study suggests that the advantages of peanut/maize intercropping for yield mainly comes from aboveground interspecific competition for maize and belowground interspecific facilitation for peanut, and their respective yield can be enhanced by N and P. These findings are important for managing the intercropping system and optimizing the benefits from using this system.展开更多
The size and shape of the effective test area are crucial to consider when short-crested waves are created by segmented wavemakers. The range of the effective test area of short-crested waves simulated by two-sided se...The size and shape of the effective test area are crucial to consider when short-crested waves are created by segmented wavemakers. The range of the effective test area of short-crested waves simulated by two-sided segmented wavemakers is analyzed in this paper. The experimental investigation on the wave field distribution of short-crested waves generated by two-sided segmented wavemakers is conducted by using an array of wave gauges. Wave spectra and directional spreading function are analyzed and the results show that when the main direction is at a certain angle with the normal line of wave generators, the wave field of 3D short-crested waves generated by two-sided segmented wavemakers has good spatial uniformity within the model test area. The effective test area can provide good wave environments for seakeeping model tests of various ocean engineering structures in the deep ocean engineering basin.展开更多
In this paper, we consider the two-sided first exit problem for jump diffusion processes having jumps with rational Laplace transforms. We investigate the probabilistic property of conditional memorylessness, and driv...In this paper, we consider the two-sided first exit problem for jump diffusion processes having jumps with rational Laplace transforms. We investigate the probabilistic property of conditional memorylessness, and drive the joint distribution of the first exit time from an interval and the overshoot over the boundary at the exit time.展开更多
An experiment was conducted during Kharif seasons of 2009 and 2010 on sandy loam soil of West Bengal, India to evaluate the productivity and economic viability of maize + legume intercropping systems in additive as w...An experiment was conducted during Kharif seasons of 2009 and 2010 on sandy loam soil of West Bengal, India to evaluate the productivity and economic viability of maize + legume intercropping systems in additive as well as in replacement series with different row proportions. Maize (Zea rnays L.) cv. "Vijay" (composite), green gram (Vigna radiata L.) cv. "Samrat", black gram (Vigna mungo L.) cv. "Sarada", soybean (Glycine max L. Merril) cv. "PK 327" and peanut (Arachis hypogaea L.) cv. "JL 24", were tested in monoculture as well as in intercropping situations with 1:1 (additive series) and 1:2 ratios (replacement series). The result indicated that intercropped legumes improved the yield components of maize and offered some bonus yield. The highest maize grain yield (2,916.28 kg/ha) and maize equivalent yield (4,831.45 kg/ha) were recorded with maize + green gram (1:1) and maize + peanut (1:I), respectively. The values of all the competition functions were always greater than unity and maize + black gram (1:2) recorded the highest values of land equivalent ratio (1.433), area time equivalent ratio (1.374) and land equivalent coefficient (0.421). Maximum monetary advantage (Rs. 10,579.13) was found with maize + green gam (l:1). Maize + peanut (1:2) combination recorded the highest relative net return (2.01), net return (Rs. 28,523.08), benefit-cost ratio (2.76) ad per day return (Rs. 259.30).展开更多
文摘BACKGROUND Pulse oximetry has become a cornerstone technology in healthcare,providing non-invasive monitoring of oxygen saturation levels and pulse rate.Despite its widespread use,the technology has inherent limitations and challenges that must be addressed to ensure accurate and reliable patient care.AIM To comprehensively evaluate the advantages,limitations,and challenges of pulse oximetry in clinical practice,as well as to propose recommendations for optimizing its use.METHODS A systematic literature review was conducted to identify studies related to pulse oximetry and its applications in various clinical settings.Relevant articles were selected based on predefined inclusion and exclusion criteria,and data were synthesized to provide a comprehensive overview of the topic.RESULTS Pulse oximetry offers numerous advantages,including non-invasiveness,real-time feedback,portability,and costeffectiveness.However,several limitations and challenges were identified,including motion artifacts,poor peripheral perfusion,ambient light interference,and patient-specific factors such as skin pigmentation and hemoglobin variants.Recommendations for optimizing pulse oximetry use include technological advancements,education and training initiatives,quality assurance protocols,and interdisciplinary collaboration.CONCLUSION Pulse oximetry is crucial in modern healthcare,offering invaluable insights into patients’oxygenation status.Despite its limitations,pulse oximetry remains an indispensable tool for monitoring patients in diverse clinical settings.By implementing the recommendations outlined in this review,healthcare providers can enhance the effectiveness,accessibility,and safety of pulse oximetry monitoring,ultimately improving patient outcomes and quality of care.
文摘With the rapid development of big data,cloud computing,artificial intelligence,and other technologies,digital construction has gradually become a crucial means of enterprise development,significantly impacting the operation and management activities of enterprises.Outward Foreign Direct Investment(OFDI)is one of the key pathways for Chinese enterprises to“go global,”contributing to improved economic efficiency and promoting national economic development.Therefore,studying the advantages of digitalization in OFDI activities will aid in exploring effective methods for Chinese enterprises to engage in OFDI within the digital economy and provide an important foundation for strategic enterprise planning and national policy formulation.This paper combines the current state of OFDI among Chinese enterprises,analyzes the advantages and roles of digital construction in OFDI,and explores relevant countermeasures,aiming to provide theoretical references for enterprises’OFDI activities in the context of digitalization.
基金Shandong Province Traditional Chinese Medicine Science and Technology Project“Effects of Buccal Acupuncture on PGF2α,5-HT,and Uterine Hemodynamics in Patients with Primary Dysmenorrhea”(M-2022240)“Effects of the Combination of Oxycodone and Difference Anesthetic Drugs on Postoperative Cognitive Function and Inflammation-Related Serological Indicators in Elderly ERCP Patients”(ezmr2023-037)。
文摘Objective:To evaluate the clinical advantages of laparoscopic transverse abdominal wall suspension in treating pelvic organ prolapse.Methods:Sixty patients diagnosed with moderate to severe pelvic organ prolapse and underwent surgical treatment in our hospital between January 2022 and December 2023 were selected.According to different surgical methods,they were divided into an observation group(given laparoscopic transverse abdominal wall suspension)and a control group(given transvaginal mesh implantation),with 30 subjects/group.The data on perioperative-related indicators,quality of life scores,postoperative recurrence,and complications of the two groups of patients were collected.Results:The postoperative hospitalization days and intraoperative bleeding volume of the observation group were significantly lower than those of the control group,but had longer operation time than that of the control group(P<0.05).The differences between the two groups were statistically significant 6 months after surgery,and the Pelvic Floor Disease Quality of Life Impact Questionnaire(PFIQ-7)score of the observation group was significantly higher than the control group(P<0.05).Both groups of patients completed 12 months of follow-up without any postoperative recurrence.The number of complications in the observation group was slightly lower than that of the control group(P>0.05).Conclusion:Laparoscopic transverse abdominal wall suspension was more effective in treating pelvic organ prolapse and is an ideal surgical procedure.
基金Supported by Fundamental Research Program of Technical Innovation of Chang an University(CHD2009JC045)Rural Tourism Development Program of the"Twe lfth Five-Year"Plan of Shaanxi Province~~
文摘The concept of rural tourist resources was introduced to analyze the present rural tourism development in Shaanxi Province,tourist resources in its rural areas were investigated comprehensively,structures,quantity and quality of 7 major types of both natural and cultural tourist resources were evaluated,and resource combinations were also analyzed from the perspective of geological location.Characteristics and advantages of rural tourist resources in Shaanxi Province were summarized as "abundant,diversified and high-quality";rural cultural tourist resources took the Absolute predominance and had great development potentials;cultural tourist resources such as folk cultures had distinctive regional features;rural natural tourist resources had obvious regional characteristics;resources were reasonably combined,each resource region had its own features.This study aimed at providing scientific support for the development,planning and protection of rural tourist resources in Shaanxi Province.
基金Supported by Earmarked Fund for China Agriculture Research System(CARS-26)Science and Technology Development Fund of Guangxi Academy of AgriculturalSciences(GNK2013YZ26)National Space Breeding Project(2006HT100113)~~
文摘[Objective]This study aimed to clarify the spatial patterns of comparative advantage of watermelon production in Guangxi Zhuang Autonomous Region, to pro-vide theoretical basis for the development of watermelon industry in China. [Method] Based on the agricultural statistics data of Guangxi and al over China, yield com-parative advantage (YCA) index, efficiency comparative advantage (ECA) index, scale comparative advantage (SCA) index, concentration ratio comparative advantage (CRCA) index, comprehensive comparative advantage (CCA) index, ratio of yield per unit area (RYPA) index and sowing area ratio (SAR) index were established and calculated to determine the watermelon production comparative advantages in 31 provinces (cities) in China. Spacial patterns of the comparative advantages were produced by using GIS software. [Result] Nine provinces Shandong, Henan, Anhui, Hebei, Hubei, Jiangsu, Hunan, Zhejiang and Guangxi were the dominant regions in watermelon production al over the country. The Central and Eastern China showed the integrated comparative advantage in watermelon production, while the Southern, Northeastern, Northern and Northwestern China can be considered as the potential places for watermelon production in future. Southwest China gave more priority to watermelon production, so the comparative advantages kept increasing here. [Con-clusion] Based on this study, watermelon production should be a prior consideration among the agricultural products in Guangxi. Related measures should be developed to optimize the regional distribution of watermelon in Guangxi and China to promote healthy competition in watermelon production.
文摘In English teachinig,the use of multi-media makes a vivid learning atmosphere for students.It can get a better teaching effect in all-around education.Meanwhile,thereare some problems inevitably in this field,leaving for the English teachers to solve.
文摘With the world globalization, China's communication with other countries has become more frequent. It is in great demand that a large number of college graduates who not only master their major but also do well in communication in English with English speakers. However, such graduates are scare because the backward teaching method-the Grammar-Traditional Method, cannot meet what the contemporary Chinese society demands. The reforms of the college English teaching are urgent and necessary. This paper first explores the major problems existing in the college English teaching. Furthermore, it introduces the basic theory of the Communicative Approach and analyzes its advantages in college English teaching.
基金Project (No. 50175018) supported by the National Natural ScienceFoundation of China
文摘Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM.
文摘In this study, forced nonlinear vibration of a circular micro-plate under two-sided electrostatic, two-sided Casimir and external harmonic forces is investigated analytically. For this purpose, at first, von Karman plate theory including geometrical nonlinearity is used to obtain the deflection of the micro-plate. Galerkin decomposition method is then employed, and nonlinear ordinary differential equations (ODEs) of motion are determined. A harmonic balance method (HBM) is applied to equations and analytical relation for nonlineaT frequency response (F-R) curves are derived for two categories (including and neglecting Casimir force) separately. The analytical results for three cases:(1) semi-linear vibration;(2) weakly nonlinear vibration;(3) highly non linear vibration, are validated by comparing with the numerical solutio ns. After validation, the effects of the voltage and Casimir force on the natural frequency of two-sided capacitor system are investigated. It is shown that by assuming Casimir force in small gap distances, reduction of the natural frequency is considerable. The influences of the applied voltage, damping, micro-plate thickness and Casimir force on the frequency response curves have been presented too. The results of this study can be useful for modeling circular parallel-plates in nano /microelectromechanical transducers such as microphones and pressure sensors.
基金Supported by National Natural Science Foundation of China(Grant Nos.51275366,50875190,51305311)Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20134219110002)
文摘Due to the NP-hardness of the two-sided assembly line balancing (TALB) problem, multiple constraints existing in real applications are less studied, especially when one task is involved with several constraints. In this paper, an effective hybrid algorithm is proposed to address the TALB problem with multiple constraints (TALB-MC). Considering the discrete attribute of TALB-MC and the continuous attribute of the standard teaching-learning-based optimization (TLBO) algorithm, the random-keys method is hired in task permutation representation, for the purpose of bridging the gap between them. Subsequently, a special mechanism for handling multiple constraints is developed. In the mechanism, the directions constraint of each task is ensured by the direction check and adjustment. The zoning constraints and the synchronism constraints are satisfied by teasing out the hidden correlations among constraints. The positional constraint is allowed to be violated to some extent in decoding and punished in cost fimction. Finally, with the TLBO seeking for the global optimum, the variable neighborhood search (VNS) is further hybridized to extend the local search space. The experimental results show that the proposed hybrid algorithm outperforms the late acceptance hill-climbing algorithm (LAHC) for TALB-MC in most cases, especially for large-size problems with multiple constraints, and demonstrates well balance between the exploration and the exploitation. This research proposes an effective and efficient algorithm for solving TALB-MC problem by hybridizing the TLBO and VNS.
文摘The phenomena of TL are connected with the defect structures of the atomic lattice of the material concerned, and hence are very sensitive to changes in defection of the country rocks status as induced by the mineralizing solution. In other words, the TL of the country rocks from the mineralized area should be quite different from that in the intact barren area.Besides the high sensitivity as mentioned above, advantages of the application of TL techniques to the mineral exploration the easiness in accessing to proper samples, the easy preparation of samples and the quickness in sample processing all amount to convenience and economy of the techniques, indicating the high competitiveness of the TL mineral exploration method, especially during the development stage of mining operations.
基金Supported by Research Project on Education and Teaching Reform of Higher Education Institutions in Hainan Province(Hnjg2016-12)Education and Teaching Reform Research Project of Hainan University(hdjy1604)
文摘The development of information technology has changed people's learning methods. Fragmented learning,as an informal learning method,has become an important way to accept new knowledge and learn new technologies. Through analyzing the connotation,characteristics,and advantages and disadvantages of fragmented learning,this paper came up with reasonable recommendations for fragmented learning. To truly become systematic and holistic knowledge,fragmented knowledge must be explored,understood,integrated and internalized. This paper is expected to play an important guiding role in building a lifelong learning society.
基金Key Projectof Scientific and TechnologicalCommittee of Shanghai(No.0 3 11110 0 5 )
文摘A two-sided assembly line is typically found in plants producing large-sized products. Its advantages over a one-sided line and the difficulties faced in two-sided line balancing problems were discussed. A mathematical model for two-ALB problem was suggested. A modification of the “ranked positional weight” method, namely two-ALB RPW for two-ALB problems was developed. Experiments were carried out to verify the performance of the proposed method and the results show that it is effective in solving two-sided assembly line balancing problems.
文摘企业竞争优势依赖于其所生存的环境,金融危机爆发之后的经济下行使装备制造企业竞争优势的来源发生了根本性的改变.通过对辽宁9 家企业的问卷调查,探究了辽宁装备制造企业的竞争优势现状,厘清了竞争优势维度对财务绩效的不同作用,进一步研究了竞争优势的提升路径.研究表明:经济下行对企业竞争优势的影响较大;目前竞争优势主要来源于低成本优势和新产品研发优势,但近年来新产品研发得到了较快的发展,而成本优势正在大幅减弱;产品开发、技术资源、软件和市场份额对总资产报酬率影响较大,而成本、与用户信任程度关系、质量和Y R IN技术资源对销售利润率影响较大;产品开发、成本、服务、与用户信任程度和性能是企业需要关注的重点.
基金supported by the National Key Research and Development Program of China(2017YFD0200202)the National Natural Science Foundation of China(U1404315)+1 种基金the China Scholarship Council(201608410278)the Natural Science Foundation of Henan Province(182300410014)。
文摘Intercropping of maize(Zea mays L.) and peanut(Arachis hypogaea L.) often results in greater yields than the respective sole crops. However, there is limited knowledge of aboveground and belowground interspecific interactions between maize and peanut in field. A two-year field experiment was conducted to investigate the effects of interspecific interactions on plant growth and grain yield for a peanut/maize intercropping system under different nitrogen(N) and phosphorus(P) levels. The method of root separation was employed to differentiate belowground from aboveground interspecific interactions. We observed that the global interspecific interaction effect on the shoot biomass of the intercropping system decreased with the coexistence period, and belowground interaction contributed more than aboveground interaction to advantages of the intercropping in terms of shoot biomass and grain yield. There was a positive effect from aboveground and belowground interspecific interactions on crop plant growth in the intercropping system, except that aboveground interaction had a negative effect on peanut during the late coexistence period. The advantage of intercropping on grain came mainly from increased maize yield(means 95%) due to aboveground interspecific competition for light and belowground interaction(61%–72% vs. 28%–39% in fertilizer treatments). There was a negative effect on grain yield from aboveground interaction for peanut, but belowground interspecific interaction positively affected peanut grain yield.The supply of N, P, or N + P increased grain yield of intercropped maize and the contribution from aboveground interspecific interaction. Our study suggests that the advantages of peanut/maize intercropping for yield mainly comes from aboveground interspecific competition for maize and belowground interspecific facilitation for peanut, and their respective yield can be enhanced by N and P. These findings are important for managing the intercropping system and optimizing the benefits from using this system.
基金financially supported by the National Natural Science Foundation of China(Grant No.51239007)
文摘The size and shape of the effective test area are crucial to consider when short-crested waves are created by segmented wavemakers. The range of the effective test area of short-crested waves simulated by two-sided segmented wavemakers is analyzed in this paper. The experimental investigation on the wave field distribution of short-crested waves generated by two-sided segmented wavemakers is conducted by using an array of wave gauges. Wave spectra and directional spreading function are analyzed and the results show that when the main direction is at a certain angle with the normal line of wave generators, the wave field of 3D short-crested waves generated by two-sided segmented wavemakers has good spatial uniformity within the model test area. The effective test area can provide good wave environments for seakeeping model tests of various ocean engineering structures in the deep ocean engineering basin.
文摘In this paper, we consider the two-sided first exit problem for jump diffusion processes having jumps with rational Laplace transforms. We investigate the probabilistic property of conditional memorylessness, and drive the joint distribution of the first exit time from an interval and the overshoot over the boundary at the exit time.
文摘An experiment was conducted during Kharif seasons of 2009 and 2010 on sandy loam soil of West Bengal, India to evaluate the productivity and economic viability of maize + legume intercropping systems in additive as well as in replacement series with different row proportions. Maize (Zea rnays L.) cv. "Vijay" (composite), green gram (Vigna radiata L.) cv. "Samrat", black gram (Vigna mungo L.) cv. "Sarada", soybean (Glycine max L. Merril) cv. "PK 327" and peanut (Arachis hypogaea L.) cv. "JL 24", were tested in monoculture as well as in intercropping situations with 1:1 (additive series) and 1:2 ratios (replacement series). The result indicated that intercropped legumes improved the yield components of maize and offered some bonus yield. The highest maize grain yield (2,916.28 kg/ha) and maize equivalent yield (4,831.45 kg/ha) were recorded with maize + green gram (1:1) and maize + peanut (1:I), respectively. The values of all the competition functions were always greater than unity and maize + black gram (1:2) recorded the highest values of land equivalent ratio (1.433), area time equivalent ratio (1.374) and land equivalent coefficient (0.421). Maximum monetary advantage (Rs. 10,579.13) was found with maize + green gam (l:1). Maize + peanut (1:2) combination recorded the highest relative net return (2.01), net return (Rs. 28,523.08), benefit-cost ratio (2.76) ad per day return (Rs. 259.30).