The problem of price scissors difference between industrial products and agricultural products is one of the important problems in China. It impacts not only the living standard improvement of farmers but also the eco...The problem of price scissors difference between industrial products and agricultural products is one of the important problems in China. It impacts not only the living standard improvement of farmers but also the economic value of cultivated land, furthermore results in the direct and indirect loss of cultivated land resources. China＇s cultivated land area has decreased dramatically in recent years. An important reason for the decrease is the relatively low cost of cultivated land occupancy, which results from the distortion of economic value of cultivated land due to the existence of scissors difference. This study firstly analyzed the dynamic change of scissors difference and calculated the absolute and relative magnitude of scissors difference from 1997 to 2002, then computed the economic value of cultivated land before and after scissors difference adjustment in 2002, and finally discussed the inverted scissors difference. Results suggest that the scissors difference has a remarkable impact on the economic value of cultivated land, and the adjustment of scissors difference even inverted scissors difference to the economic value of cultivated land is indisoensable.展开更多
Endoscopic submucosal dissection （ESD） with a knife is a technically demanding procedure a ssociated with ahigh complication rate. The shortcomings of this meth-od are the inability to fix the knife to the target le...Endoscopic submucosal dissection （ESD） with a knife is a technically demanding procedure a ssociated with ahigh complication rate. The shortcomings of this meth-od are the inability to fix the knife to the target lesion,and compression of the lesion. These can lead to major complications such as perforation and bleeding. To reduce the risk of complications related to ESD, we developed a new grasping type scissors forceps （GSF）,which can grasp and incise the targeted tissue using electrosurgical current. Colonoscopy on a 55-year-old woman revealed a 10-ram rectal submucosal nodule.The histological diagnosis of the specimen obtained by biopsy was carcinoid tumor. Endoscopic ultrasonog-raphy demonstrated a hypoechoic solid tumor limitedto the submucosa without lymph node involvement. Itwas safely and accurately resected without unexpectedincision by ESD using a GSF. No delayed hemorrhage or perforation occurred. Histological examination confirmed the carcinoid tumor was completely excisedwith negative resection margin.展开更多
As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general par...As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general parallel mechanism.In this paper,an unequal-length scissors mechanism(ULSM)is proposed by changing the position of the internal rotational joint through a basic scissors mechanism.A scissors hoop-rib truss deployable antenna mechanism(SHRTDAM)is constructed by replacing the parabolic rib with the ULSM.Kinematic analysis of SHRTDAM is conducted,and the degree of freedom(DOF)of the whole antenna mechanism is analyzed based on screw theory,the result showed that it has only one DOF.Velocity and acceleration characteristics of SHRTDAM are obtained by the screw derivative and rotation transformation.Based on Lagrange equation,dynamic model of this mechanism is established,the torque required to drive the mechanism is simulated and verified by Adams and MATLAB software.In addition,a ground experiment prototype of 1.5-m diameter was fabricated and a deployment test is conducted,which demonstrated the mobility and deployment performance of the whole mechanism.The mechanism proposed in this paper can provide a good reference for the design and analysis of large aperture space deployable antennas.展开更多
AIM:To evaluate the efficacy and safety of grasper type scissors(GTS)for endoscopic submucosal dissection(ESD)of gastric epithelial neoplasia.METHODS:The study was performed by 4 endoscopists in 4 institutions affilia...AIM:To evaluate the efficacy and safety of grasper type scissors(GTS)for endoscopic submucosal dissection(ESD)of gastric epithelial neoplasia.METHODS:The study was performed by 4 endoscopists in 4 institutions affiliated to The Catholic University of Korea.ESD was performed in 76 consecutive patients with gastric epithelial neoplasia by using the GTS(37 patients)or the hook knife plus coagrasper(HKC)(39 patients).The complete resection rate,complication rate,total time elapsed and elapsed time per square centimeter of the dissected specimen were analyzed between the GTS and HKC group.RESULTS:The mean age of the GTS group was 62.3±11.4 years and mean age of the HKC group was 65.6±10.1 years.Differentiated adenocarcinoma was found in32.4%in the GTS group and 33.3%in the HKC group.The procedures were performed without interruption in every case in both groups.The en bloc resection rates of both groups were 100%.The total time elapsed during the procedure was 44.54±21.72 min in the GTS group and 43.77±21.84 min in the HKC group(P=0.88)and the time elapsed per square centimeter of the resected lesion was 7.53±6.35 min/cm2in the GTS group and 6.92±5.93 min/cm2in the HKC group(P=0.66).The overall complication rate was not significantly different between the two groups.CONCLUSION:GTS is a safe and effective device for ESD compared with HKC.ESD can be performed with GTS alone,which can reduce the costs for ESD.展开更多
Aiming at the noise of helicopter scissors tail-rotor,an advanced numerical method is established by combining computational fluid dynamics(CFD)model with Farassat 1 A(F1 A)formula.In this method,Navier-tokes(N-S)equa...Aiming at the noise of helicopter scissors tail-rotor,an advanced numerical method is established by combining computational fluid dynamics(CFD)model with Farassat 1 A(F1 A)formula.In this method,Navier-tokes(N-S)equations are used as governing equations,and the flow field is solved at quasi-steady and unsteady states in hover and forward fight,respectively,based on two different types of embedded grid systems.A simple and effective solution approach is provided for the generation difficulty of donor cells caused by the close gap among scissors tail-rotor blades.Using the CFD calculation results as input,the thickness noise,loading noise and total noise of tail-rotor are calculated by F1 Aformula.By the method,numerical examples on rotor flowfield and noise are performed and the results are compared with available data.Then,aerodynamic and acoustic characteristics of scissors tail-rotor are emphatically calculated in both hover and forward flight.Furthermore,the research on the effects of blade-tip shape parameters on scissors tail-rotor noise is carried out.Also,the scissors tail-rotor is compared with the conventional tail-rotor,and the results show that in hover,the noise of a scissors tail-rotor is not always the smaller one.展开更多
We propose a new scheme to enhance the performance of the Gussian-modulated coherent-state continuous-variable measurement-device-independent quantum key distribution(CV-MDI-QKD)system via quantum scissors(QS)operatio...We propose a new scheme to enhance the performance of the Gussian-modulated coherent-state continuous-variable measurement-device-independent quantum key distribution(CV-MDI-QKD)system via quantum scissors(QS)operation at Bob's side.As an non-deterministic amplifying setup,we firstly introduce the QS-enhanced CV-MDI-QKD protocol and then investigate the success probability of the QS operation in accordance with the equivalent one-way scheme.Afterwards,we investigate the effect of the QS operation on the proposed scheme and analyze the performance of the QS-enhanced CV-MDI-QKD system under the extreme asymmetric circumstance.Simulation results show that the QS operation can indeed improve the performance of the CV-MDI-QKD system considerably.QS-enhanced CV-MDI-QKD protocol outperforms the original CV-MDI-QKD protocol in both the maximum transmission distance and the secret key rate.Moreover,the better the performance of QS operation,the more significant the improvement of performance of the system.展开更多
A scheme is proposed to investigate the non-classical states generated by a quantum scissors device(QSD) operating on the the cavity mode of an optomechanical system. When the catalytic QSD acts on the cavity mode of ...A scheme is proposed to investigate the non-classical states generated by a quantum scissors device(QSD) operating on the the cavity mode of an optomechanical system. When the catalytic QSD acts on the cavity mode of the optomechanical system, the resulting state contains only the vacuum, single-photon and two-photon states depending upon the coupling parameter of the optomechanical system as well as the transmission coefficients of beam splitters(BSs). Especially, the output state is just a class of multicomponent cat state truncations at time t = 2π by choosing the appropriate value of coupling parameter. We discuss the success probability of such a state and the fidelity between the output state and input state via QSD. Then the linear entropy is used to investigate the entanglement between the two subsystems, finding that QSD operation can enhance their entanglement degree. Furthermore, we also derive the analytical expression of the Wigner function(WF) for the cavity mode via QSD and numerically analyze the WF distribution in phase space at time t =2π. These results show that the high non-classicality of output state can always be achieved by modulating the coupling parameter of the optomechanical system as well as the transmittance of BSs.展开更多
Endoscopic submucosal dissection(ESD)is a globally accepted minimally invasive therapy for early-stage gastrointestinal tract tumors.Although numerous electrosurgical knives have been developed for ESD,technical diffi...Endoscopic submucosal dissection(ESD)is a globally accepted minimally invasive therapy for early-stage gastrointestinal tract tumors.Although numerous electrosurgical knives have been developed for ESD,technical difficulties and high complication rates(bleeding and perforation)have limited their use worldwide.The grasping-type scissors forceps[clutch cutter(CC)]is the first forceps-type resection device developed with reference to hemostatic forceps.The aim was to allow easy and safe ESD throughout the gastro-intestinal tract,as a biopsy technique,using one device.The CC can grasp the target tissue accurately and pull it away from the underlying muscle layer prior to energizing the tissue,for safe and effective incision and hemostasis during ESD.Reported clinical studies showed that ESD using the CC(ESD-CC)is a safe(perforation rate:0%-3.6%;delayed bleeding rate:0%-4.2%),technically efficient(en-bloc resection rate:88.9%-100%),and single-device method for dissecting early-stage gastrointestinal tract tumors.The ESD-CC technique is simple and easy to learn because it can be completed simply by repeating the grasp,pull,and coagulate and/or incise actions using an electrosurgical current.The reported self-completion rate by nonexperts was significantly better with the CC than with conventional knives(61.7%vs 24.5%,respectively;P<0.001).Furthermore,the CC is used for other endoscopic therapies,such as endoscopic polypectomy for large pedunculated polyps,endoscopic myotomy for Zenker’s diverticulum,endoscopic treatment of buried bumper syndrome,and endoscopic necrosectomy for wall-off pancreatic necrosis.The initial reports using CC for these therapies have shown favorable results.In this review,we describe the structural features of the CC,how to use the instrument,efficacies of ESD-CC,and other unique endoscopic therapies using the CC.展开更多
The production of scissors in China can be traced back about 4000 years. In ancient times, Chinese people called scissors "cutters" or "reamers". The cutters unearthed from an ancient tomb of the W...The production of scissors in China can be traced back about 4000 years. In ancient times, Chinese people called scissors "cutters" or "reamers". The cutters unearthed from an ancient tomb of the Western Han Dynasty (206B.C. —— 8 A.D.) in Luoyang of Henan Province were made in the shape of the figure "8" with an opening at its top and without any pivot. They were bent into shape with an iron bar blade at both ends.展开更多
Objective:The present study aims to compare the clinical efficacy of laparoscopic partial nephrectomy using a harmonic scalpel versus traditional scissor.Methods:A retrospective review was conducted in patients with l...Objective:The present study aims to compare the clinical efficacy of laparoscopic partial nephrectomy using a harmonic scalpel versus traditional scissor.Methods:A retrospective review was conducted in patients with localized renal tumors and scheduled for laparoscopic partial nephrectomy from January 2015 to December 2019.Eventually,225 patients joined this retrospective study.Patients were divided into the harmonic scalpel group or scissor group based on the method used,with 71 cases and 154 cases respectively.Propensity score matching(1:1)was performed to adjust for potential baseline confounders,and each group had 57 cases.Patient characteristics,perioperative clinical results,complications,and oncological results were compared between the two groups.Results:After matching,patient characteristics were not significantly different between the two groups.The scissor group was associated with a significantly shorter operative time(105 min vs.130 min,p<0.001),shorter warm ischemia time(19.35 min vs.22.07 min,p?0.005).However,the harmonic scalpel group was associated with significantly less estimated blood loss(20 mL vs.30 mL,p?0.013)and shorter length of stay(8 d vs.10 d,p?0.040).There was no significantly difference in indwelling time of drainage tube,perioperative complication,oncological outcomes or recurrence rates.Conclusions:The harmonic scalpel is used safely and effectively in laparoscopic partial nephrectomy,and has benefits in intraoperative blood loss and length of stay.展开更多
Based on the extended projected shell model-a microscopic nuclear many-body theory-our recently published article [Phys.Rev.Lett.129,042502(2022)] found an unexpected phenomenon(ΔI=2 bifurcation) in rotational bands ...Based on the extended projected shell model-a microscopic nuclear many-body theory-our recently published article [Phys.Rev.Lett.129,042502(2022)] found an unexpected phenomenon(ΔI=2 bifurcation) in rotational bands associated with scissors vibrations in^(156)Gd.In the present work,we extended the study by systematically changing the model parameters(deformation and strength of the monopole-pairing force) for the^(156)Gd calculation.We also calculated additional isotopes and isotones with respect to ^(156)Gd.In all calculations,we found a similar occurrence of the ΔI=2 bifurcation in the results.Thus,we confirmed that the bifurcation behavior of the scissors rotational bands originates from the self-organizing effects of deformed proton and neutron bodies during the scissors motion,independently of the model parameters.展开更多
The intrinsic vibrational motion and the rotational behavior of the scissors mode in well deformed nuclei are investigated with an angular-momentum-projected approach,which is interpreted as a generator-coordinatemeth...The intrinsic vibrational motion and the rotational behavior of the scissors mode in well deformed nuclei are investigated with an angular-momentum-projected approach,which is interpreted as a generator-coordinatemethod with the generator coordinates corresponding to the degrees of freedom of interest.The picture of the intrinsic and rotational motion of the scissors mode is illustrated from the collective wave function within the framework of the generator-coordinate-method.The harmonicity of the scissors vibration is found to arise naturally from the present model but can be disturbed by the Coriolis effect as spin increases.The odd and even spin members of the rotational band based on the scissors mode rotate about different axes perpendicular to each other,leading to the flipping moment of inertia and the consequent splitting behavior that has been suggested previously.展开更多
In recent years,countries worldwide have actively advocated electric vehicles for environmental protection.How-ever,restrictions on the driving range and charging have hampered the promotion of electric vehicles.This ...In recent years,countries worldwide have actively advocated electric vehicles for environmental protection.How-ever,restrictions on the driving range and charging have hampered the promotion of electric vehicles.This study proposes a portable,auxiliary photovoltaic power system based on a foldable scissors mechanism for electric vehicles.The system includes a photovoltaic power generation module and an electricity transfer module.The photovoltaic power generation module built based on a foldable scissors mechanism is five times smaller than in its unfolded state,improving its portability in its folded state.The electricity transfer module transfers electricity into the cabin via wireless power transfer units and stores electricity in supercapacitors.Solar simulation exper-iments were conducted to evaluate the system’s performance:maximum output power of 1.736 W is measured when the load is 5Ω,while maximum wireless power transfer efficiency is up to 57.7% with 10Ω load.An elec-tric vehicle in Chengdu city was simulated for a case study.The results show that the annual output of a single photovoltaic power system can drive the MINIEV for 423.625 km,indicating that the proposed system would be able to supply power for electric vehicles as an auxiliary power supply system.展开更多
911恐怖袭击美国的事件,对美国的经济、文化乃至大众的心理产生的冲击波巨大而又久远。机场强化了安检工作。以下七类用品皆不准携带入机舱: scissors(剪刀),corkscrews(开塞钻),umbrellas,nail clippers,plastic guns,razors and knive...911恐怖袭击美国的事件,对美国的经济、文化乃至大众的心理产生的冲击波巨大而又久远。机场强化了安检工作。以下七类用品皆不准携带入机舱: scissors(剪刀),corkscrews(开塞钻),umbrellas,nail clippers,plastic guns,razors and knives of any description(种类),因为它们被认为是:potentialweapons。展开更多
Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling ...Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling degree and temporal changes of economic development level and resource and environment carrying ca- pacity in the central area of Yunnan Province. Results indicated that （i） the economic development level and resource and environment carrying capacity in the central area of Yunnan Province mainly experienced strong decoupling, weak decoupling, and ex- pansive negative coupling, and in general it was strong decoupling, and it took on re- verse ＂N＂ in temporal changes. （ii） Change rate of economic development level in the central area of Yunnan Province was greater than zero, but the amplitude of change was not large, while the change rate of resource and environment carrying capacity was negative in 2007-2008, and it was positive in the rest years; from 2007, it took on gradual expansion trend, and scissors difference gradually increased after experi- encing reverse ＂V＂ change. （iii） The strong decoupling was the main situation and it reached the peak value in T5 period and T6 pedod.展开更多
Endoscopic submucosal dissection (ESD) with a knife is a technically demanding procedure associated with a high complication rate.The shortcomings of this method are the deficiencies of fixing the knife to the target ...Endoscopic submucosal dissection (ESD) with a knife is a technically demanding procedure associated with a high complication rate.The shortcomings of this method are the deficiencies of fixing the knife to the target lesion,and of compressing it.These shortcomings can lead to major complications such as perforation and bleeding.To reduce the risk of complications related to ESD,we developed a new grasping type scissors forceps (Clutch Cutter,Fujifilm,Japan) which can grasp and incise the targeted tissue using an electrosurgical current.Esophagogastroduodenoscopy on a 59-year-old Japanese man revealed a 16mm esophageal submucosal nodule with central depression.Endoscopic ultrasonography demonstrated a hypoechoic solid tumor limited to the submucosa without lymph node involvement.The histologic diagnosis of the specimen obtained by biopsy was granular cell tumor.It was safely and accurately resected without unexpected incision by ESD using the CC.No delayed hemorrhage or perforation occurred.Histological examination confirmed that the granular cell tumor was completely excised with negative resection margin.We report herein a case of esophageal granular cell tumor successfully treated by an ESD technique using the CC.展开更多
In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with onl...In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with only one liner motor while ensuring the stability of the lift. Finite element analysis in ANSYS is performed to verify the material strength. The control system with Sunplus SCM achieves the voice control of wheelchair walking and lifting.展开更多
According to the present situation that the current road wrecker with a large occupied volume is mainlytowed by truck and cannot be applied to car clearing on the congested or narrow road, based on the structure ofexi...According to the present situation that the current road wrecker with a large occupied volume is mainlytowed by truck and cannot be applied to car clearing on the congested or narrow road, based on the structure ofexisting electric pallet truck, a small sized road wrecker is designed, which has some advantages such as smallvolume, convenient to use and flexible operation. The main structure, hydraulic system and working principle aredesigned and illustrated in this paper. The optimization design of mechanism multi-objective function for scissorslifting device is carried out by using MATLAB optimization toolbox, and installation position parameters of hydrau-lic cylinder is optimized by using optimization design concept, which decreases the maximum output force of hy-draulic cylinder and reduces the energy consumption of hydraulic system, and provides a reliable basis for the im-provement design of this kind of small sized road wrecker.展开更多
Many natural disasters cause not only critical situations for facilities and resident’s residents’ life, but also significant damage to economy. It is obvious that quick rescue action must be undertaken and that the...Many natural disasters cause not only critical situations for facilities and resident’s residents’ life, but also significant damage to economy. It is obvious that quick rescue action must be undertaken and that there are many problems due to the occurrence of secondary disasters at rescue worksite. Basing Based on the previous study of deployable structures and the concept of the multi-folding micro-structures, we propose a new type of foldable bridge in form of scissor structure called the Mobile-bridge?. In this paper, we discuss the vehicle passing test performed on the real-scale Mobile-bridge in order to evaluate its mechanical characteristics and application limits. Moreover, we verified the compatibility between the result of calculations and experiments by means of theoretical modelling. The results show that it is sufficient to treat the load as equivalent nodal forces applied at the joints without including the stiffness of the deck.展开更多
This paper investigates the mechanism, scale, and development tendencies of capital flow between China＇s rural and urban areas over 35 years of reform and opening up. The following conclusions are reached. First, bet...This paper investigates the mechanism, scale, and development tendencies of capital flow between China＇s rural and urban areas over 35 years of reform and opening up. The following conclusions are reached. First, between 1978 and2012, the net capital flow from rural areas to urban areas through the fiscal and financial systems and the price scissors of industrial and agricultural goods amounted to RMB 26. 66 trillion （by 2012price level）. Second, prior to 1994, the outflow of rural capital continued accelerating; starting from the late 1990s, the net outflow of rural capital slowed down but the overall scale remained significant. Third, the contributions by the three capital flow channels （the fiscal system, financial institutions, and the price scissors of agricultural and industrial products） to the net outflow of rural capital varied greatly across different historical periods： prior to the establishment of the market economic system （1978-1993）, most of the rural capital left the countryside in the form of price scissors of agricultural and industrial goods; during the 15 years after the establishment of the market economic system in China （1994-2007）, rural capital flowed into cities mainly through the fiscal system; with the market-oriented reform of the rural financial systems in recent years （2008-2012）, financial institutions became a major channel for the extraction of rural capital. Based on our study, we believe that in the course of more than three decades of reform and opening up, China was in the stage of extracting rural capital and that the contemporary China should enter into a new stage of development by diverting resources to the countryside to support its development. Our recommendation is that the existing fiscal and financial policies be adjusted to boost fiscal spending on agriculture, farmers, and the countryside, and to establish an inclusive, modern rural financial system.展开更多
文摘The problem of price scissors difference between industrial products and agricultural products is one of the important problems in China. It impacts not only the living standard improvement of farmers but also the economic value of cultivated land, furthermore results in the direct and indirect loss of cultivated land resources. China＇s cultivated land area has decreased dramatically in recent years. An important reason for the decrease is the relatively low cost of cultivated land occupancy, which results from the distortion of economic value of cultivated land due to the existence of scissors difference. This study firstly analyzed the dynamic change of scissors difference and calculated the absolute and relative magnitude of scissors difference from 1997 to 2002, then computed the economic value of cultivated land before and after scissors difference adjustment in 2002, and finally discussed the inverted scissors difference. Results suggest that the scissors difference has a remarkable impact on the economic value of cultivated land, and the adjustment of scissors difference even inverted scissors difference to the economic value of cultivated land is indisoensable.
文摘Endoscopic submucosal dissection （ESD） with a knife is a technically demanding procedure a ssociated with ahigh complication rate. The shortcomings of this meth-od are the inability to fix the knife to the target lesion,and compression of the lesion. These can lead to major complications such as perforation and bleeding. To reduce the risk of complications related to ESD, we developed a new grasping type scissors forceps （GSF）,which can grasp and incise the targeted tissue using electrosurgical current. Colonoscopy on a 55-year-old woman revealed a 10-ram rectal submucosal nodule.The histological diagnosis of the specimen obtained by biopsy was carcinoid tumor. Endoscopic ultrasonog-raphy demonstrated a hypoechoic solid tumor limitedto the submucosa without lymph node involvement. Itwas safely and accurately resected without unexpectedincision by ESD using a GSF. No delayed hemorrhage or perforation occurred. Histological examination confirmed the carcinoid tumor was completely excisedwith negative resection margin.
基金supported by the National Natural Science Foundation of China(Grant Nos.52105035 and 52075467)the Natural Science Foundation of Hebei Province of China(Grant No.E2021203109)+1 种基金the State Key Laboratory of Robotics and Systems(HIT)(Grant No.SKLRS-2021-KF-15)the Industrial Robot Control and Reliability Technology Innovation Center of Hebei Province(Grant No.JXKF2105).
文摘As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general parallel mechanism.In this paper,an unequal-length scissors mechanism(ULSM)is proposed by changing the position of the internal rotational joint through a basic scissors mechanism.A scissors hoop-rib truss deployable antenna mechanism(SHRTDAM)is constructed by replacing the parabolic rib with the ULSM.Kinematic analysis of SHRTDAM is conducted,and the degree of freedom(DOF)of the whole antenna mechanism is analyzed based on screw theory,the result showed that it has only one DOF.Velocity and acceleration characteristics of SHRTDAM are obtained by the screw derivative and rotation transformation.Based on Lagrange equation,dynamic model of this mechanism is established,the torque required to drive the mechanism is simulated and verified by Adams and MATLAB software.In addition,a ground experiment prototype of 1.5-m diameter was fabricated and a deployment test is conducted,which demonstrated the mobility and deployment performance of the whole mechanism.The mechanism proposed in this paper can provide a good reference for the design and analysis of large aperture space deployable antennas.
基金Supported by Research grants from Korean Society of Gastrointestinal Endoscopy
文摘AIM:To evaluate the efficacy and safety of grasper type scissors(GTS)for endoscopic submucosal dissection(ESD)of gastric epithelial neoplasia.METHODS:The study was performed by 4 endoscopists in 4 institutions affiliated to The Catholic University of Korea.ESD was performed in 76 consecutive patients with gastric epithelial neoplasia by using the GTS(37 patients)or the hook knife plus coagrasper(HKC)(39 patients).The complete resection rate,complication rate,total time elapsed and elapsed time per square centimeter of the dissected specimen were analyzed between the GTS and HKC group.RESULTS:The mean age of the GTS group was 62.3±11.4 years and mean age of the HKC group was 65.6±10.1 years.Differentiated adenocarcinoma was found in32.4%in the GTS group and 33.3%in the HKC group.The procedures were performed without interruption in every case in both groups.The en bloc resection rates of both groups were 100%.The total time elapsed during the procedure was 44.54±21.72 min in the GTS group and 43.77±21.84 min in the HKC group(P=0.88)and the time elapsed per square centimeter of the resected lesion was 7.53±6.35 min/cm2in the GTS group and 6.92±5.93 min/cm2in the HKC group(P=0.66).The overall complication rate was not significantly different between the two groups.CONCLUSION:GTS is a safe and effective device for ESD compared with HKC.ESD can be performed with GTS alone,which can reduce the costs for ESD.
文摘Aiming at the noise of helicopter scissors tail-rotor,an advanced numerical method is established by combining computational fluid dynamics(CFD)model with Farassat 1 A(F1 A)formula.In this method,Navier-tokes(N-S)equations are used as governing equations,and the flow field is solved at quasi-steady and unsteady states in hover and forward fight,respectively,based on two different types of embedded grid systems.A simple and effective solution approach is provided for the generation difficulty of donor cells caused by the close gap among scissors tail-rotor blades.Using the CFD calculation results as input,the thickness noise,loading noise and total noise of tail-rotor are calculated by F1 Aformula.By the method,numerical examples on rotor flowfield and noise are performed and the results are compared with available data.Then,aerodynamic and acoustic characteristics of scissors tail-rotor are emphatically calculated in both hover and forward flight.Furthermore,the research on the effects of blade-tip shape parameters on scissors tail-rotor noise is carried out.Also,the scissors tail-rotor is compared with the conventional tail-rotor,and the results show that in hover,the noise of a scissors tail-rotor is not always the smaller one.
基金Project supported by the National Natural Science Foundation of China(Grant No.62001383)the Scientific Research Plan Project of Shaanxi Education Department(Natural Science Special Project)(Grant No.19JK0847).
文摘We propose a new scheme to enhance the performance of the Gussian-modulated coherent-state continuous-variable measurement-device-independent quantum key distribution(CV-MDI-QKD)system via quantum scissors(QS)operation at Bob's side.As an non-deterministic amplifying setup,we firstly introduce the QS-enhanced CV-MDI-QKD protocol and then investigate the success probability of the QS operation in accordance with the equivalent one-way scheme.Afterwards,we investigate the effect of the QS operation on the proposed scheme and analyze the performance of the QS-enhanced CV-MDI-QKD system under the extreme asymmetric circumstance.Simulation results show that the QS operation can indeed improve the performance of the CV-MDI-QKD system considerably.QS-enhanced CV-MDI-QKD protocol outperforms the original CV-MDI-QKD protocol in both the maximum transmission distance and the secret key rate.Moreover,the better the performance of QS operation,the more significant the improvement of performance of the system.
基金Project supported by the National Natural Science Foundation of China (Grant No.11704051)the Qinglan Project of the Jiangsu Education Department and the Research Foundation of Six Talents Peaks Project in Jiangsu Province,China (Grant No.XNY-093)。
文摘A scheme is proposed to investigate the non-classical states generated by a quantum scissors device(QSD) operating on the the cavity mode of an optomechanical system. When the catalytic QSD acts on the cavity mode of the optomechanical system, the resulting state contains only the vacuum, single-photon and two-photon states depending upon the coupling parameter of the optomechanical system as well as the transmission coefficients of beam splitters(BSs). Especially, the output state is just a class of multicomponent cat state truncations at time t = 2π by choosing the appropriate value of coupling parameter. We discuss the success probability of such a state and the fidelity between the output state and input state via QSD. Then the linear entropy is used to investigate the entanglement between the two subsystems, finding that QSD operation can enhance their entanglement degree. Furthermore, we also derive the analytical expression of the Wigner function(WF) for the cavity mode via QSD and numerically analyze the WF distribution in phase space at time t =2π. These results show that the high non-classicality of output state can always be achieved by modulating the coupling parameter of the optomechanical system as well as the transmittance of BSs.
文摘Endoscopic submucosal dissection(ESD)is a globally accepted minimally invasive therapy for early-stage gastrointestinal tract tumors.Although numerous electrosurgical knives have been developed for ESD,technical difficulties and high complication rates(bleeding and perforation)have limited their use worldwide.The grasping-type scissors forceps[clutch cutter(CC)]is the first forceps-type resection device developed with reference to hemostatic forceps.The aim was to allow easy and safe ESD throughout the gastro-intestinal tract,as a biopsy technique,using one device.The CC can grasp the target tissue accurately and pull it away from the underlying muscle layer prior to energizing the tissue,for safe and effective incision and hemostasis during ESD.Reported clinical studies showed that ESD using the CC(ESD-CC)is a safe(perforation rate:0%-3.6%;delayed bleeding rate:0%-4.2%),technically efficient(en-bloc resection rate:88.9%-100%),and single-device method for dissecting early-stage gastrointestinal tract tumors.The ESD-CC technique is simple and easy to learn because it can be completed simply by repeating the grasp,pull,and coagulate and/or incise actions using an electrosurgical current.The reported self-completion rate by nonexperts was significantly better with the CC than with conventional knives(61.7%vs 24.5%,respectively;P<0.001).Furthermore,the CC is used for other endoscopic therapies,such as endoscopic polypectomy for large pedunculated polyps,endoscopic myotomy for Zenker’s diverticulum,endoscopic treatment of buried bumper syndrome,and endoscopic necrosectomy for wall-off pancreatic necrosis.The initial reports using CC for these therapies have shown favorable results.In this review,we describe the structural features of the CC,how to use the instrument,efficacies of ESD-CC,and other unique endoscopic therapies using the CC.
文摘The production of scissors in China can be traced back about 4000 years. In ancient times, Chinese people called scissors "cutters" or "reamers". The cutters unearthed from an ancient tomb of the Western Han Dynasty (206B.C. —— 8 A.D.) in Luoyang of Henan Province were made in the shape of the figure "8" with an opening at its top and without any pivot. They were bent into shape with an iron bar blade at both ends.
基金This study was funded by Medical Health Science and Technology Project of Zhejiang Provincial Health Commission(2020375998).
文摘Objective:The present study aims to compare the clinical efficacy of laparoscopic partial nephrectomy using a harmonic scalpel versus traditional scissor.Methods:A retrospective review was conducted in patients with localized renal tumors and scheduled for laparoscopic partial nephrectomy from January 2015 to December 2019.Eventually,225 patients joined this retrospective study.Patients were divided into the harmonic scalpel group or scissor group based on the method used,with 71 cases and 154 cases respectively.Propensity score matching(1:1)was performed to adjust for potential baseline confounders,and each group had 57 cases.Patient characteristics,perioperative clinical results,complications,and oncological results were compared between the two groups.Results:After matching,patient characteristics were not significantly different between the two groups.The scissor group was associated with a significantly shorter operative time(105 min vs.130 min,p<0.001),shorter warm ischemia time(19.35 min vs.22.07 min,p?0.005).However,the harmonic scalpel group was associated with significantly less estimated blood loss(20 mL vs.30 mL,p?0.013)and shorter length of stay(8 d vs.10 d,p?0.040).There was no significantly difference in indwelling time of drainage tube,perioperative complication,oncological outcomes or recurrence rates.Conclusions:The harmonic scalpel is used safely and effectively in laparoscopic partial nephrectomy,and has benefits in intraoperative blood loss and length of stay.
基金Funded by the Special Foundation for Theoretical PhysicsNational Natural Science Foundation of China (NSFC)(12347125)China Postdoctoral Science Foundation (2023TQ0217, 2024M751951)。
文摘Based on the extended projected shell model-a microscopic nuclear many-body theory-our recently published article [Phys.Rev.Lett.129,042502(2022)] found an unexpected phenomenon(ΔI=2 bifurcation) in rotational bands associated with scissors vibrations in^(156)Gd.In the present work,we extended the study by systematically changing the model parameters(deformation and strength of the monopole-pairing force) for the^(156)Gd calculation.We also calculated additional isotopes and isotones with respect to ^(156)Gd.In all calculations,we found a similar occurrence of the ΔI=2 bifurcation in the results.Thus,we confirmed that the bifurcation behavior of the scissors rotational bands originates from the self-organizing effects of deformed proton and neutron bodies during the scissors motion,independently of the model parameters.
基金partly supported by the Fundamental Research Funds for the Central Universities,Lanzhou University(lzujbky-2023-04)the Natural Science Foundation of Gansu Province,China(24JRRA400)the National Natural Science Foundation for Young Scientists of China(11905172)。
文摘The intrinsic vibrational motion and the rotational behavior of the scissors mode in well deformed nuclei are investigated with an angular-momentum-projected approach,which is interpreted as a generator-coordinatemethod with the generator coordinates corresponding to the degrees of freedom of interest.The picture of the intrinsic and rotational motion of the scissors mode is illustrated from the collective wave function within the framework of the generator-coordinate-method.The harmonicity of the scissors vibration is found to arise naturally from the present model but can be disturbed by the Coriolis effect as spin increases.The odd and even spin members of the rotational band based on the scissors mode rotate about different axes perpendicular to each other,leading to the flipping moment of inertia and the consequent splitting behavior that has been suggested previously.
基金supported by the National Natural Science Foundation of China under grants no.51975490the Science and Technology Projects of Sichuan under grant nos.2021JDRC0118,2021JDRC0096,2021YFSY0059,and 2021YFQ0055.
文摘In recent years,countries worldwide have actively advocated electric vehicles for environmental protection.How-ever,restrictions on the driving range and charging have hampered the promotion of electric vehicles.This study proposes a portable,auxiliary photovoltaic power system based on a foldable scissors mechanism for electric vehicles.The system includes a photovoltaic power generation module and an electricity transfer module.The photovoltaic power generation module built based on a foldable scissors mechanism is five times smaller than in its unfolded state,improving its portability in its folded state.The electricity transfer module transfers electricity into the cabin via wireless power transfer units and stores electricity in supercapacitors.Solar simulation exper-iments were conducted to evaluate the system’s performance:maximum output power of 1.736 W is measured when the load is 5Ω,while maximum wireless power transfer efficiency is up to 57.7% with 10Ω load.An elec-tric vehicle in Chengdu city was simulated for a case study.The results show that the annual output of a single photovoltaic power system can drive the MINIEV for 423.625 km,indicating that the proposed system would be able to supply power for electric vehicles as an auxiliary power supply system.
文摘911恐怖袭击美国的事件,对美国的经济、文化乃至大众的心理产生的冲击波巨大而又久远。机场强化了安检工作。以下七类用品皆不准携带入机舱: scissors(剪刀),corkscrews(开塞钻),umbrellas,nail clippers,plastic guns,razors and knives of any description(种类),因为它们被认为是:potentialweapons。
基金Supported by Scientific Research Foundation of Yunnan Provincial Department of Education(2015J088)~~
文摘Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling degree and temporal changes of economic development level and resource and environment carrying ca- pacity in the central area of Yunnan Province. Results indicated that （i） the economic development level and resource and environment carrying capacity in the central area of Yunnan Province mainly experienced strong decoupling, weak decoupling, and ex- pansive negative coupling, and in general it was strong decoupling, and it took on re- verse ＂N＂ in temporal changes. （ii） Change rate of economic development level in the central area of Yunnan Province was greater than zero, but the amplitude of change was not large, while the change rate of resource and environment carrying capacity was negative in 2007-2008, and it was positive in the rest years; from 2007, it took on gradual expansion trend, and scissors difference gradually increased after experi- encing reverse ＂V＂ change. （iii） The strong decoupling was the main situation and it reached the peak value in T5 period and T6 pedod.
文摘Endoscopic submucosal dissection (ESD) with a knife is a technically demanding procedure associated with a high complication rate.The shortcomings of this method are the deficiencies of fixing the knife to the target lesion,and of compressing it.These shortcomings can lead to major complications such as perforation and bleeding.To reduce the risk of complications related to ESD,we developed a new grasping type scissors forceps (Clutch Cutter,Fujifilm,Japan) which can grasp and incise the targeted tissue using an electrosurgical current.Esophagogastroduodenoscopy on a 59-year-old Japanese man revealed a 16mm esophageal submucosal nodule with central depression.Endoscopic ultrasonography demonstrated a hypoechoic solid tumor limited to the submucosa without lymph node involvement.The histologic diagnosis of the specimen obtained by biopsy was granular cell tumor.It was safely and accurately resected without unexpected incision by ESD using the CC.No delayed hemorrhage or perforation occurred.Histological examination confirmed that the granular cell tumor was completely excised with negative resection margin.We report herein a case of esophageal granular cell tumor successfully treated by an ESD technique using the CC.
基金Supported by Special Topic of the Ministry of Education about Humanities and Social Sciences(12JDGC007)ZheJiang Henglin Chair Industry Co.,Ltd.-Hefei University of Technology Green Seat and Intelligent House Innovate Team
文摘In order to achieve a wheelchair lift function, this paper designs a tri-scissors mechanism. Through the so-called H-type transmission and L-type swing rod, the three scissors mechanisms lift in the same rate with only one liner motor while ensuring the stability of the lift. Finite element analysis in ANSYS is performed to verify the material strength. The control system with Sunplus SCM achieves the voice control of wheelchair walking and lifting.
文摘According to the present situation that the current road wrecker with a large occupied volume is mainlytowed by truck and cannot be applied to car clearing on the congested or narrow road, based on the structure ofexisting electric pallet truck, a small sized road wrecker is designed, which has some advantages such as smallvolume, convenient to use and flexible operation. The main structure, hydraulic system and working principle aredesigned and illustrated in this paper. The optimization design of mechanism multi-objective function for scissorslifting device is carried out by using MATLAB optimization toolbox, and installation position parameters of hydrau-lic cylinder is optimized by using optimization design concept, which decreases the maximum output force of hy-draulic cylinder and reduces the energy consumption of hydraulic system, and provides a reliable basis for the im-provement design of this kind of small sized road wrecker.
基金Star Light Metal Industry Co., Ltd., Akashin Corporation
文摘Many natural disasters cause not only critical situations for facilities and resident’s residents’ life, but also significant damage to economy. It is obvious that quick rescue action must be undertaken and that there are many problems due to the occurrence of secondary disasters at rescue worksite. Basing Based on the previous study of deployable structures and the concept of the multi-folding micro-structures, we propose a new type of foldable bridge in form of scissor structure called the Mobile-bridge?. In this paper, we discuss the vehicle passing test performed on the real-scale Mobile-bridge in order to evaluate its mechanical characteristics and application limits. Moreover, we verified the compatibility between the result of calculations and experiments by means of theoretical modelling. The results show that it is sufficient to treat the load as equivalent nodal forces applied at the joints without including the stiffness of the deck.
基金supported by the key project of the National Social Sciences Fund:Study on the Synchronized Development of Institutional Innovation for Agricultural Modernization.Industrialization,IT Application.and Urbanization(Grant No.13AZD003)the soft science project of the Ministry of Agriculture for 2014:Study on the New Price Scissors of Urban and Rural Areas(Grant No.D201415)
文摘This paper investigates the mechanism, scale, and development tendencies of capital flow between China＇s rural and urban areas over 35 years of reform and opening up. The following conclusions are reached. First, between 1978 and2012, the net capital flow from rural areas to urban areas through the fiscal and financial systems and the price scissors of industrial and agricultural goods amounted to RMB 26. 66 trillion （by 2012price level）. Second, prior to 1994, the outflow of rural capital continued accelerating; starting from the late 1990s, the net outflow of rural capital slowed down but the overall scale remained significant. Third, the contributions by the three capital flow channels （the fiscal system, financial institutions, and the price scissors of agricultural and industrial products） to the net outflow of rural capital varied greatly across different historical periods： prior to the establishment of the market economic system （1978-1993）, most of the rural capital left the countryside in the form of price scissors of agricultural and industrial goods; during the 15 years after the establishment of the market economic system in China （1994-2007）, rural capital flowed into cities mainly through the fiscal system; with the market-oriented reform of the rural financial systems in recent years （2008-2012）, financial institutions became a major channel for the extraction of rural capital. Based on our study, we believe that in the course of more than three decades of reform and opening up, China was in the stage of extracting rural capital and that the contemporary China should enter into a new stage of development by diverting resources to the countryside to support its development. Our recommendation is that the existing fiscal and financial policies be adjusted to boost fiscal spending on agriculture, farmers, and the countryside, and to establish an inclusive, modern rural financial system.
