The application of the Euclidean division theorem for the positive integers allowed us to establish a set which contains all the prime numbers and this set we called it set of supposedly prime numbers and we noted it ...The application of the Euclidean division theorem for the positive integers allowed us to establish a set which contains all the prime numbers and this set we called it set of supposedly prime numbers and we noted it E<sub>sp</sub>. We subsequently established from the previous set the set of non-prime numbers (the set of numbers belonging to this set and which are not prime) denoted E<sub>np</sub>. We then extracted from the set of supposedly prime numbers the numbers which are not prime and the set of remaining number constitutes the set of prime numbers denoted E<sub>p</sub>. We have deduced from the previous set, the set of prime numbers between two natural numbers. We have explained during our demonstrations the origin of the twin prime numbers and the structure of the chain of prime numbers.展开更多
The massive growth of wireless traffic goes hand in hand with the deployment of advanced radio interfaces as well as network densification. This growth has a direct impact on the radio access architecture, which today...The massive growth of wireless traffic goes hand in hand with the deployment of advanced radio interfaces as well as network densification. This growth has a direct impact on the radio access architecture, which today is moving from centralized to distributed deployments through the use of a large number of access points (APs). This paper verifies the feasibility of deploying multiple APs in series on a single line in a ring topology in a cell-less network. On the one hand, this technique will further improve the communication capacity and flexibility of a Radio-over-Fiber (RoF) based mobile communication system and will reduce its construction cost. And on the other hand, this deployment topology is a solution to achieve a massive cell-free Multiple-Input Multiple-Output (MIMO) architecture and a cost-effective fronthaul solution. First, a passive optical add/drop multiplexer (OADM) is used to extract and add downlink and uplink signals from the remote access points of one kilometer. Then, a deployment model is developed with version 17 Optisystem software. The results obtained showed that the quadrature amplitude modulation (QAM) does not adapt to this multi-carrier transmission to deploy several AP in series on a single line. Thus, the performance degradation increases when the number of APs integrated on the line increases.展开更多
We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends ...We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.展开更多
Compared with the conventional casting process, digital pattern-less casting technology has many advantages such as good machining accuracy, a short processing cycle, and low production cost. It is a new rapid manufac...Compared with the conventional casting process, digital pattern-less casting technology has many advantages such as good machining accuracy, a short processing cycle, and low production cost. It is a new rapid manufacturing technology for castings, integrated with CAD/CAM, casting, CNC machining and many other advanced technologies. With this digital casting technology, no pattern is needed for making molds; it is precise, f lexible, and green. Usually, art castings have complex structures and are made in small batches or even made in a single-piece, especially for large-sized art castings. So it has the shortcomings of high cost, low eff iciency and long time for making a pattern to produce art castings with the conventional casting processes. However, the digital pattern-less casting technology can be applied to fabricate art castings, since it can greatly shorten the manufacturing cycle and lower the production cost, thus having a very good prospect. In this study, based on the digital pattern-less casting technology, a plaque casting with artistic Chinese characters(a Chinese poem) was designed and manufactured, and the production process was demonstrated in detail.展开更多
AIM To design a miniature magnetically anchored and controlled camera system to reduce the number of trocars which are required for laparoscopy.METHODS The system consists of a miniature magnetically anchored camera w...AIM To design a miniature magnetically anchored and controlled camera system to reduce the number of trocars which are required for laparoscopy.METHODS The system consists of a miniature magnetically anchored camera with a 30° downward angle, an external magnetically anchored unit, and a vision output device. The camera weighs 12 g, measures Φ10.5 mm × 55 mm and has two magnets, a vision model, a light source, and a metal hexagonal nut. To test the prototype, the camera was inserted through a 12-mm conventional trocar in an ex vivo real liver laparoscopic training system. A trocar-less laparoscopic cholecystectomy was performed 6 times using a 12-mm and a 5-mm conventional trocar. In addition, the same procedure was performed in four canine models.RESULTS Both procedures were successfully performed using only two conventional laparoscopic trocars. The cholecystectomy was completed without any major complication in 42 min(38-45 min) in vitro and in 50 min(45-53 min) using an animal model. This camera was anchored and controlled by an external unit magnetically anchored on the abdominal wall. The camera could generate excellent image. with no instrument collisions.CONCLUSION The camera system we designed provides excellent optics and can be easily maneuvered. The number of conventional trocars is reduced without adding technical difficulties.展开更多
Some places in Henan Province are investigated by using sample surveys and interviews. Result shows that land circulation in less developed agricultural area of Henan Province has the characteristics of small scale,si...Some places in Henan Province are investigated by using sample surveys and interviews. Result shows that land circulation in less developed agricultural area of Henan Province has the characteristics of small scale,single form,short period,and circulation land in economic core region. Problems in land circulation are as follows:slow transfer of rural surplus labor force,hard implementation of fundamental land circulation,complicated mentality towards rural land circulation,many misgivings about land circulation,the unformed social service system of land circulation,and imperfect agricultural risk prevention mechanism for circulated land use. Based on the characteristics of land circulation,suggestions for promoting the land circulation of less developed agricultural areas are put forward in order to solve the problems in land circulation and to lay the foundation for effective implementation of land circulation,such as speeding up the development of urbanization,developing the circulation of collective land,effectively implementing the laws and regulations of rural collective land circulation,transferring land according to law,establishing market mechanism of agricultural land circulation,promoting the agricultural industrialization,establishing market mechanism of agricultural land circulation,promoting the agricultural industrialization,energetically readjusting rural industrial structure,and developing economy with local characteristics.展开更多
The classic way of treatment of tibial plateau fractures with an extensive approach, opening of the knee and compressive internal fixation can lead to major complications such as infection, skin necrosis and knee stif...The classic way of treatment of tibial plateau fractures with an extensive approach, opening of the knee and compressive internal fixation can lead to major complications such as infection, skin necrosis and knee stiffness. Here we present a less invasive and thus safer surgical technique, and its indications and results. Twenty patients with various types of fractures according to Schatzker’s classification (mainly V and VI) were treated during a time period of seven years. Surgical treatment usually consisted of a combination of percutaneous canulated screws with a hybrid external fixator. In three cases canulated screws were combined with a laterally applied anatomic locking plate. Patients were followed up for six months to three years postoperatively. Indications as well as intra and postoperative parameters such as surgical time, stability of fixation, blood loss, wound healing, infection, fracture healing and final result were studied. No major complications were recorded either early or later. The use of external οr less invasive internal fixation in combination with percutaneous canulated screws appears to be an adequate method for the treatment of most types of these fractures.展开更多
"Iess is more"是20世纪20年代密斯·凡·德·罗提出的一项经典建筑设计法则。该法则对同时代乃至随后的几代建筑师都产生了深刻的影响。在西方近现代建筑发展史上该法则曾倍受推崇,也饱受诟病。在密斯本人逝世4..."Iess is more"是20世纪20年代密斯·凡·德·罗提出的一项经典建筑设计法则。该法则对同时代乃至随后的几代建筑师都产生了深刻的影响。在西方近现代建筑发展史上该法则曾倍受推崇,也饱受诟病。在密斯本人逝世40周年之际,本文简要回顾了该法则产生的时代背景,并对其在不同时代所产生的影响进行了分析和阐述,最终致力于提出在可持续发展的社会大背景下,该法则对现代建筑设计仍然具有极其深刻的借鉴意义和推广价值。展开更多
As a famous English contemporary women writer, Doris Lessing always puts her attention on the female characters that live in South Africa. Their lives are pathetic and sad. This thesis tries to analyze one of Lessing&...As a famous English contemporary women writer, Doris Lessing always puts her attention on the female characters that live in South Africa. Their lives are pathetic and sad. This thesis tries to analyze one of Lessing's short stories— Winter in July from Lacan's three Orders approach. Lessing is a feminist, but the deeper description of the desire and struggle in men's inner world in her works is also remarkable.展开更多
As a prolific writer of British literature in 20th century,Doris Lessing creates literary works which challenge in both theme and writing style.In her works,the style is distinctive and various,the thought s are deep,...As a prolific writer of British literature in 20th century,Doris Lessing creates literary works which challenge in both theme and writing style.In her works,the style is distinctive and various,the thought s are deep,ideas are sharp and new.This pa per studies women's subject consciousness and their awakenings,and at the same time,intends to explore her transcendence to western feminist criticism.展开更多
Since the early 1980s, China’s rural industry has gained rapid growth. However. the development of China’s rural industry, like the development of the national economy as a whole, is characterized by great regional ...Since the early 1980s, China’s rural industry has gained rapid growth. However. the development of China’s rural industry, like the development of the national economy as a whole, is characterized by great regional imbalance. From the economically developed coastal areas to. The hinterland and western frontier areas, the level of rural industrialization ebbs progressively. How to narrow down this imbalance and to speed up the development of rural industry in the less developed areas is one of the most important tasks in China’s economic reform and development. The paper adopts an approach of combining statistical data analysis with typical case study to this research with special reference to Henan Province.展开更多
The influence of material gate position in bur-den-flow rate has been studied by simulating exper-iments.A mathematical model describing the char-acteristics of burden-flow at the material gate ofbell-less top blast f...The influence of material gate position in bur-den-flow rate has been studied by simulating exper-iments.A mathematical model describing the char-acteristics of burden-flow at the material gate ofbell-less top blast furnace(BF)is established in thispaper,in an attempt to solve the problems in bur-den distribution,especially to eliminate the over-lapping or disconnection of the burden at the be-ginning and at the end of a ring,which plays a quiteimportant role in the blast furnace operation.展开更多
The trend toward lead-free or lead-less perovskite solar cells(PSCs) has attracted increasing attention over the past few years because the toxicity of lead(Pb) is one of the substantial restrictions for large-scale a...The trend toward lead-free or lead-less perovskite solar cells(PSCs) has attracted increasing attention over the past few years because the toxicity of lead(Pb) is one of the substantial restrictions for large-scale applications. Researchers have investigated the viability of substituting Pb with other elements(group 14 elements, group 2 elements, transition-metal elements, and group 13 and 15 elements) in the three-dimensional(3 D) perovskites by theoretical calculations and experimental explorations. In this paper, recent research progress in Pb-less and Pb-free PSCs on the perovskite compositions, deposition methods, and device structures are summarized and the main problems that hinder the enhancement of device efficiency and stability are discussed in detail. To date, the fully Sn-based PSCs have shown a power conversion efficiency(PCE) of 8.12% and poor device stability. However, lead-less PSCs have shown higher PCE and a better stability. In addition, the introduction of double-perovskite materials also draws researchers' attention. We believe that the engineering of elemental composition, perovskite deposition methods, and interfacial modification are critical for the future development of Pb-less and Pb-free PSCs.展开更多
文摘The application of the Euclidean division theorem for the positive integers allowed us to establish a set which contains all the prime numbers and this set we called it set of supposedly prime numbers and we noted it E<sub>sp</sub>. We subsequently established from the previous set the set of non-prime numbers (the set of numbers belonging to this set and which are not prime) denoted E<sub>np</sub>. We then extracted from the set of supposedly prime numbers the numbers which are not prime and the set of remaining number constitutes the set of prime numbers denoted E<sub>p</sub>. We have deduced from the previous set, the set of prime numbers between two natural numbers. We have explained during our demonstrations the origin of the twin prime numbers and the structure of the chain of prime numbers.
文摘The massive growth of wireless traffic goes hand in hand with the deployment of advanced radio interfaces as well as network densification. This growth has a direct impact on the radio access architecture, which today is moving from centralized to distributed deployments through the use of a large number of access points (APs). This paper verifies the feasibility of deploying multiple APs in series on a single line in a ring topology in a cell-less network. On the one hand, this technique will further improve the communication capacity and flexibility of a Radio-over-Fiber (RoF) based mobile communication system and will reduce its construction cost. And on the other hand, this deployment topology is a solution to achieve a massive cell-free Multiple-Input Multiple-Output (MIMO) architecture and a cost-effective fronthaul solution. First, a passive optical add/drop multiplexer (OADM) is used to extract and add downlink and uplink signals from the remote access points of one kilometer. Then, a deployment model is developed with version 17 Optisystem software. The results obtained showed that the quadrature amplitude modulation (QAM) does not adapt to this multi-carrier transmission to deploy several AP in series on a single line. Thus, the performance degradation increases when the number of APs integrated on the line increases.
文摘We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.
基金financially supported by the National Natural Science Foundation of China(No.51105257)
文摘Compared with the conventional casting process, digital pattern-less casting technology has many advantages such as good machining accuracy, a short processing cycle, and low production cost. It is a new rapid manufacturing technology for castings, integrated with CAD/CAM, casting, CNC machining and many other advanced technologies. With this digital casting technology, no pattern is needed for making molds; it is precise, f lexible, and green. Usually, art castings have complex structures and are made in small batches or even made in a single-piece, especially for large-sized art castings. So it has the shortcomings of high cost, low eff iciency and long time for making a pattern to produce art castings with the conventional casting processes. However, the digital pattern-less casting technology can be applied to fabricate art castings, since it can greatly shorten the manufacturing cycle and lower the production cost, thus having a very good prospect. In this study, based on the digital pattern-less casting technology, a plaque casting with artistic Chinese characters(a Chinese poem) was designed and manufactured, and the production process was demonstrated in detail.
基金Supported by National Natural Science Foundation of China(Major Instrumental Program)No.81127005the Science and Technology Innovation Project of Shaanxi Province,China,No.S2016TNGY0119
文摘AIM To design a miniature magnetically anchored and controlled camera system to reduce the number of trocars which are required for laparoscopy.METHODS The system consists of a miniature magnetically anchored camera with a 30° downward angle, an external magnetically anchored unit, and a vision output device. The camera weighs 12 g, measures Φ10.5 mm × 55 mm and has two magnets, a vision model, a light source, and a metal hexagonal nut. To test the prototype, the camera was inserted through a 12-mm conventional trocar in an ex vivo real liver laparoscopic training system. A trocar-less laparoscopic cholecystectomy was performed 6 times using a 12-mm and a 5-mm conventional trocar. In addition, the same procedure was performed in four canine models.RESULTS Both procedures were successfully performed using only two conventional laparoscopic trocars. The cholecystectomy was completed without any major complication in 42 min(38-45 min) in vitro and in 50 min(45-53 min) using an animal model. This camera was anchored and controlled by an external unit magnetically anchored on the abdominal wall. The camera could generate excellent image. with no instrument collisions.CONCLUSION The camera system we designed provides excellent optics and can be easily maneuvered. The number of conventional trocars is reduced without adding technical difficulties.
基金Supported by the Soft Science Research Program of Hubei Provincial Science & Technology Department (0413020310)
文摘Some places in Henan Province are investigated by using sample surveys and interviews. Result shows that land circulation in less developed agricultural area of Henan Province has the characteristics of small scale,single form,short period,and circulation land in economic core region. Problems in land circulation are as follows:slow transfer of rural surplus labor force,hard implementation of fundamental land circulation,complicated mentality towards rural land circulation,many misgivings about land circulation,the unformed social service system of land circulation,and imperfect agricultural risk prevention mechanism for circulated land use. Based on the characteristics of land circulation,suggestions for promoting the land circulation of less developed agricultural areas are put forward in order to solve the problems in land circulation and to lay the foundation for effective implementation of land circulation,such as speeding up the development of urbanization,developing the circulation of collective land,effectively implementing the laws and regulations of rural collective land circulation,transferring land according to law,establishing market mechanism of agricultural land circulation,promoting the agricultural industrialization,establishing market mechanism of agricultural land circulation,promoting the agricultural industrialization,energetically readjusting rural industrial structure,and developing economy with local characteristics.
文摘The classic way of treatment of tibial plateau fractures with an extensive approach, opening of the knee and compressive internal fixation can lead to major complications such as infection, skin necrosis and knee stiffness. Here we present a less invasive and thus safer surgical technique, and its indications and results. Twenty patients with various types of fractures according to Schatzker’s classification (mainly V and VI) were treated during a time period of seven years. Surgical treatment usually consisted of a combination of percutaneous canulated screws with a hybrid external fixator. In three cases canulated screws were combined with a laterally applied anatomic locking plate. Patients were followed up for six months to three years postoperatively. Indications as well as intra and postoperative parameters such as surgical time, stability of fixation, blood loss, wound healing, infection, fracture healing and final result were studied. No major complications were recorded either early or later. The use of external οr less invasive internal fixation in combination with percutaneous canulated screws appears to be an adequate method for the treatment of most types of these fractures.
文摘"Iess is more"是20世纪20年代密斯·凡·德·罗提出的一项经典建筑设计法则。该法则对同时代乃至随后的几代建筑师都产生了深刻的影响。在西方近现代建筑发展史上该法则曾倍受推崇,也饱受诟病。在密斯本人逝世40周年之际,本文简要回顾了该法则产生的时代背景,并对其在不同时代所产生的影响进行了分析和阐述,最终致力于提出在可持续发展的社会大背景下,该法则对现代建筑设计仍然具有极其深刻的借鉴意义和推广价值。
文摘As a famous English contemporary women writer, Doris Lessing always puts her attention on the female characters that live in South Africa. Their lives are pathetic and sad. This thesis tries to analyze one of Lessing's short stories— Winter in July from Lacan's three Orders approach. Lessing is a feminist, but the deeper description of the desire and struggle in men's inner world in her works is also remarkable.
文摘As a prolific writer of British literature in 20th century,Doris Lessing creates literary works which challenge in both theme and writing style.In her works,the style is distinctive and various,the thought s are deep,ideas are sharp and new.This pa per studies women's subject consciousness and their awakenings,and at the same time,intends to explore her transcendence to western feminist criticism.
文摘Since the early 1980s, China’s rural industry has gained rapid growth. However. the development of China’s rural industry, like the development of the national economy as a whole, is characterized by great regional imbalance. From the economically developed coastal areas to. The hinterland and western frontier areas, the level of rural industrialization ebbs progressively. How to narrow down this imbalance and to speed up the development of rural industry in the less developed areas is one of the most important tasks in China’s economic reform and development. The paper adopts an approach of combining statistical data analysis with typical case study to this research with special reference to Henan Province.
文摘The influence of material gate position in bur-den-flow rate has been studied by simulating exper-iments.A mathematical model describing the char-acteristics of burden-flow at the material gate ofbell-less top blast furnace(BF)is established in thispaper,in an attempt to solve the problems in bur-den distribution,especially to eliminate the over-lapping or disconnection of the burden at the be-ginning and at the end of a ring,which plays a quiteimportant role in the blast furnace operation.
基金financially supported by the National Natural Science Foundation of China (Nos. 51572020 and 51772023)
文摘The trend toward lead-free or lead-less perovskite solar cells(PSCs) has attracted increasing attention over the past few years because the toxicity of lead(Pb) is one of the substantial restrictions for large-scale applications. Researchers have investigated the viability of substituting Pb with other elements(group 14 elements, group 2 elements, transition-metal elements, and group 13 and 15 elements) in the three-dimensional(3 D) perovskites by theoretical calculations and experimental explorations. In this paper, recent research progress in Pb-less and Pb-free PSCs on the perovskite compositions, deposition methods, and device structures are summarized and the main problems that hinder the enhancement of device efficiency and stability are discussed in detail. To date, the fully Sn-based PSCs have shown a power conversion efficiency(PCE) of 8.12% and poor device stability. However, lead-less PSCs have shown higher PCE and a better stability. In addition, the introduction of double-perovskite materials also draws researchers' attention. We believe that the engineering of elemental composition, perovskite deposition methods, and interfacial modification are critical for the future development of Pb-less and Pb-free PSCs.
