The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance ...The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance to nectar(usually corolla-tube length).Evidence for the pollinator-mediated selection on tube length and evolution of multiple,correlated floral traits remains inconclusive.To gain possible insights into the strength of stabilizing selection by assessing standing phenotypic variation,we measured a series of functionally important floral traits,including corolla tube length and‘effective’tube depth and degree of style coiling.We then calculated coefficients of variation(CV)for these traits in three field populations of R.schneideriana.Unlike in most long-tubed flowers,the bottom part of the corolla tube is completely occupied by the style,with no room for nectar.The length of this portion of the corolla tube was more variable(higher CV)than the upper part of the corolla tube,suggesting that functional tube depth was under stronger stabilizing selection.The degree of style coiling was negatively related to the corolla-tube length in all three populations of R.schneideriana,suggesting that there may be conflicting selection acting on style length and corolla-tube length,which are otherwise usually tightly correlated.Given the lack of nectar in the flowers of this species,the long corolla tubes and long styles may represent morphological holdovers from ancestors that were pollinated by long-tongued pollinators,as is still seen in related species in the western Himalayas.展开更多
Background:To evaluate the efficacy of stent-assisted coiling(SAC)for the treatment of carotid ophthalmic segment aneurysm segment aneurysms(OSAs)of the internal carotid artery(ICA)through detailed long-term follow-up...Background:To evaluate the efficacy of stent-assisted coiling(SAC)for the treatment of carotid ophthalmic segment aneurysm segment aneurysms(OSAs)of the internal carotid artery(ICA)through detailed long-term follow-up of a large patient cohort.Methods:We retrospectively analyzed 88 consecutive patients with OSAs between January 2009 and January 2020 at our center.Angiographic results were evaluated using the modified Raymond grading system and clinical outcomes were evaluated using the mRS scale.The primary endpoints were major aneurysm recurrence and poor clinical outcomes for at least 18 months of follow-up.The patients were asked to attend clinical follow-up assessments and possibly undergo DSA or MR via telephone.Results:We enrolled 88 patients with 99 OSAs treated with coiling,of whom 76 were treated with SAC.The coiling procedures were successful in all 88 patients.Overall,complications occurred in 8 patients(9.1%).No procedure-related mortality was observed.67(76.1%)experienced immediate aneurysm occlusion at the end of the procedure.Long-term angiographic follow-up(18 months)was available in 45/88 aneurysms(51%)(average 18.7±5.2 months).Four patients continued their follow-up for 5 years after initial aneurysm treatment.After a clinical follow-up time of 28.7 months(range,12-51 months),85 patients(95.5%)achieved favorable clinical outcomes(mRS scores of 0-2).Conclusions:This study indicates that SAC treatment is a safe and effective therapeutic alternative for ruptured and unruptured OSAs.The procedural risks are low with relatively long-term effectiveness.展开更多
Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and serpentine.However,all three coil configurations have complex spatial geometries,which make magnet manufact...Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and serpentine.However,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications difficult.Compared with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical studies.In this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are presented.The analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current density.Then,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.展开更多
The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging(MRI)magnets requires the careful management of exogenous heat sources.A strongly shielded gradient magnetic f...The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging(MRI)magnets requires the careful management of exogenous heat sources.A strongly shielded gradient magnetic field is important for the optimal operation of cryogen-free MRI systems.In this study,we present an enhanced shielding method incorporating a regionalized stray field constraining strategy.By optimizing the constraint parameters,we could develop engineering-feasible gradient coil schemes without increasing system complexity but with the stray field intensity reduced by half.In real measurement in an integrated MRI system,the developed gradient assembly demonstrated good performance and supported to output images of excellent quality.Our findings suggested that the proposed method could potentially form a useful design paradigm for cryogen-free MRI magnets.展开更多
Research on adaptive deformable mirror technology for voice coil actuators(VCAs)is an important trend in the development of large ground-based telescopes.A voice coil adaptive deformable mirror contains a large number...Research on adaptive deformable mirror technology for voice coil actuators(VCAs)is an important trend in the development of large ground-based telescopes.A voice coil adaptive deformable mirror contains a large number of actuators,and there are problems with structural coupling and large temperature increases in their internal coils.Additionally,parameters of the traditional proportional integral derivative(PID)control cannot be adjusted in real-time to adapt to system changes.These problems can be addressed by introducing fuzzy control methods.A table lookup method is adopted to replace real-time calculations of the regular fuzzy controller during the control process,and a prototype platform has been established to verify the effectiveness and robustness of this process.Experimental tests compare the control performance of traditional and fuzzy proportional integral derivative(Fuzzy-PID)controllers,showing that,in system step response tests,the fuzzy control system reduces rise time by 20.25%,decreases overshoot by 78.24%,and shortens settling time by 67.59%.In disturbance rejection experiments,fuzzy control achieves a 46.09%reduction in the maximum deviation,indicating stronger robustness.The Fuzzy-PID controller,based on table lookup,outperforms the standard controller significantly,showing excellent potential for enhancing the dynamic performance and disturbance rejection capability of the voice coil motor actuator system.展开更多
Prompt diagnosis and therapy of aneurysms are critical for patients with nontraumatic subarachnoid hemorrhage (SAH).The aim of our study was to assess the clinical usefulness of multislice computed tomography angiog...Prompt diagnosis and therapy of aneurysms are critical for patients with nontraumatic subarachnoid hemorrhage (SAH).The aim of our study was to assess the clinical usefulness of multislice computed tomography angiography (CTA) in the surgical and endovascular treatment of intracranial aneurysms.A total of 195 cases with 206 intracranial aneurysms underwent CTA.Fifty (24%) aneurysms underwent surgical clipping while 156 (76%) aneurysms underwent endovascular coiling.In the five missed aneurysms at digital substraction angiography and the nine aneurysms with mass intracerebral hematomas,surgical treatment was successfully performed based on 16-slice CTA alone,and the other 36 aneurysms were clipped on the main basis of the CTA.The intraoperative findings correlated well with the CTA findings and all aneurysms were clipped successfully.Sixteen-slice CTA image information has been shown to determine the choice of aneurysm therapy and assist the surgical and endovascular treatment of intracranial aneurysms.展开更多
Objective:This study aimed to evaluate the clinical and angiographic outcomes of aneurysms that were completely or near-completely embolized and ascertain whether complete embolization is important in the stent-assist...Objective:This study aimed to evaluate the clinical and angiographic outcomes of aneurysms that were completely or near-completely embolized and ascertain whether complete embolization is important in the stent-assisted coiling(SAC)of intracranial aneurysms.Methods:This retrospective study enrolled 390 patients(417 aneurysms).Among them,complete(100%)or nearcomplete(>90%)angiographic obliteration of the aneurysms on immediate angiography was accomplished.Baseline characteristics,complications,angiography follow-up results,and clinical outcomes were analyzed.Results:Cumulative adverse events occurred in 30 patients(7.7%),including thromboembolic complications in 17(4.4%),intraoperative rupture in 10(2.6%),and others in 3(0.8%).Statistical analyses revealed an increased intraprocedural rupture rate in the initial completely occluded aneurysms(5.6%compared with 1.0%).The incidence of cumulative adverse events was higher in patients with completely occluded aneurysms(11.1%)than in those with near-completely occluded aneurysms(5.5%).Angiography follow-up was available for 173 aneurysms.Aneurysm occlusion status at follow-up was correlated with stent placement(p?0.000,odds ratio?5.847),size(p?0.000,odds ratio?6.446 for tiny aneurysms;and p?0.001,odds ratio?5.616 for small aneurysms),and initial aneurysm occlusion status(p?0.001,odds ratio?3.436).Complete occlusion at followup was seen in 82.6%of the initial complete occlusion group versus 63.0%of the initial near-complete occlusion group.The incidence of complete occlusion at follow-up was higher in the initial completely occluded aneurysms with SAC(100%)than in the initial completely occluded aneurysms with non-SAC(65.2%).Conclusions:Initial complete treatment may lead to higher complication rates and good clinical outcomes at follow-up.Stent placement may enhance progressive aneurysm occlusion.Initial complete occlusion with SAC can provide durable closure at follow-up.展开更多
A new intelligent control scheme for hot strip coiling temperature is presented. In this scheme, the prediction mode1 of finishing temperature and the presetting model of main cooling zone are establish based on BP ne...A new intelligent control scheme for hot strip coiling temperature is presented. In this scheme, the prediction mode1 of finishing temperature and the presetting model of main cooling zone are establish based on BP neural network, the feed-forward open-loop control model of main cooling zone is constructed based on T-S fuzzy neural network, a new improved structure of T-S fuzzy neural network is developed, and the feedback close-loop control model of precision cooling zone is obtained based on fuzzy control. The effectiveness of the proposed scheme has been demonstrated by computer simulation with a satisfactory result.展开更多
The effects of hot-strip coiling temperature on Ti(C,N) precipitation, texture and hydrogen permeation behavior in DC06 EK enamel steel were investigated by TEM, EBSD test and electrochemical hydrogen permeation exp...The effects of hot-strip coiling temperature on Ti(C,N) precipitation, texture and hydrogen permeation behavior in DC06 EK enamel steel were investigated by TEM, EBSD test and electrochemical hydrogen permeation experiment. It was found that the Ti(C,N) particles in hot-strip coarsened with increasing coiling temperature, whereas after cold-rolling and annealing, the size difference of Ti(C,N) particles was lessened. The hot-strip coiling temperature has a significant impact on the recrystallized texture in the subsequent cold-rolled and annealed sheet. Hot-strip using high temperature(700 ℃) coiling leads to strong {111} recrystallized texture in annealed sheet, with peak intensity 9.2. On the contrary, in annealed sheets using hot-strip coiling at 650 ℃, their {111} recrystallized textures were weaker, which was also reflected in their rmvalues. Even though the hydrogen diffusion coefficient is slightly lower(7.76×10^(-5) mm^2/s) in annealed sheet using low temperature coiling(600 ℃), appropriately higher coiling temperature is more suitable for DC06 EK enamel steel combining both good drawability and fish-scale resistance.展开更多
The effects of cooling rate and coiling temperature on microstructure and mechanical properties of a plain carbon steel were investigated by combining metallography and tensile experiments. The results indicate that f...The effects of cooling rate and coiling temperature on microstructure and mechanical properties of a plain carbon steel were investigated by combining metallography and tensile experiments. The results indicate that ferrite grain size is refined and bainite transformation occurs to ensure high strength and elongation, as the cooling rate is quick enough. Yield strength and tensite strength improve with the decreased finish cooling temperature, but the elongation decreases too significantly to meet the requirements. Thus, the cooling rate must be quick enough, and the appropriate coiling temperature should be carefully selected to obtain refined ferrite and a small amount of bainite to improve the strength while the plasticity is also ensured. Under this condition, the Mn element concentration can be reduced to save cost or produce higher strength steel with same chemical composition.展开更多
To improve the precision of the coiling temperature and the performance of the feedback control system with long pure time delay on hot strip mills, we analyzed the design process of the Dahlin algorithm in detail. Th...To improve the precision of the coiling temperature and the performance of the feedback control system with long pure time delay on hot strip mills, we analyzed the design process of the Dahlin algorithm in detail. The coiling temperature curves controlled by the PID algorithm and Dahlin algorithm were simulated and compared, which showed that the control precision with the Dahlin algorithm was higher than that with the PID algorithm. That was further verified by the production practice.展开更多
A measure called the Uncertainty in Unruptured Intracranial Aneurysm Patients Undergoing Endovascular Coiling Scale (UUIACS) was developed and its validity and reliability were examined. The 49 questions that comprise...A measure called the Uncertainty in Unruptured Intracranial Aneurysm Patients Undergoing Endovascular Coiling Scale (UUIACS) was developed and its validity and reliability were examined. The 49 questions that comprised the original draft of the UUIACS were created based on interview data. Based on data from 172 participants, exploratory and confirmatory factor analyses were conducted. As a result of exploratory factor analysis, the UUIACS e retained 17 items and extracted four factors (“Lack of decision-making cues”, “Lack of information and complexity of information interpretation”, “The ambiguous nature of the disease”, and “The unpredictable living with UIA”). All of the UUIACS items showed adequate internal consistency. Between the UUIAC scale and the Universal Uncertainty in Illness Scale (UUIS), the Health Locus of Control (HLC) scale, and the SF-36v2® (Japanese version), positive correlations were found between the UUIACS and UUIS, and the HLC scale at a 1% significance level indicating concurrent validity. According to confirmatory factor analysis, the UUIACS had an acceptable goodness of fit. Given these findings, the UUIACS was judged to have satisfied the criteria for use in a clinical setting, although further investigation was required.展开更多
Background: Potentially lethal, aneurysmal subarachnoid hemorrhage has a bad prognosis for many individuals. Over the past few decades, endovascular and surgical interventions have been developed, including surgical c...Background: Potentially lethal, aneurysmal subarachnoid hemorrhage has a bad prognosis for many individuals. Over the past few decades, endovascular and surgical interventions have been developed, including surgical clipping, and endovascular coiling. Patients who have aSAH are also susceptible to delayed cerebral ischemia and cerebral vasospasm. The aim of this study is to compare the outcome of endovascular coiling with surgical clipping in patients with SAH, specifically in relation to prevalence of vasospasm, in the country of Georgia. Method: In this study, we present a retrospective review of the outcomes of 217 patients with acute subarachnoid hemorrhage who underwent endovascular coiling or surgical clipping. The data were gathered from patients who are admitted to New Vision University Hospital and Caucasus Medical Center in Tbilisi, Georgia, between 2017 and 2022. Results: Vasospasm was prevalent in 217 of the patients who had aneurysmal rupture when they first appeared. Endovascular coiling or surgical clipping was used to treat aneurysmal rupture. In our sample, 24.81 percent of patients who underwent coiling experienced vasospasm after 14 days, compared to 31.25 percent of patients who underwent clipping. After endovascular coiling and surgical clipping, the severity of vasospasm was only slightly different, according to Lindegaard ratios. Finally, 32 patients (23.35 percent) died after coiling whereas 55 patients (68.75 percent) died within three decades of clipping. Conclusion: After 5 years of data collection, this study has demonstrated the most favorable option for treatment is endovascular coiling. However, the treatment choice takes multiple factors into account, and clipping is not ideal for some ruptured aneurysms. Despite the fact that endovascular coiling is usually successful and minimally invasive, complications can occur and additional monitoring and potential surgical intervention are indicated.展开更多
Objective: To evaluate and compare the outcomes of microsurgical clipping and endovascular coiling of ruptured anterior cerebral circulation aneurysms. Methods: The current study retrospectively included 61 patients p...Objective: To evaluate and compare the outcomes of microsurgical clipping and endovascular coiling of ruptured anterior cerebral circulation aneurysms. Methods: The current study retrospectively included 61 patients presented with subarachnoid hemorrhage (SAH), treated by clipping or coiling for ruptured aneurysms located in anterior circulation. Anatomic outcome and post-operative ischemic events were evaluated. The primary clinical outcomes were evaluated as operative complications while the secondary clinical outcome was evaluated by modified Rankin scale (mRS) at discharge. Results: Of 61 ruptured aneurysms, 47 and 14 were treated by surgery and coiling, respectively. The average follow-up duration was 19.1 ± 18.6 months for clipping and 21.7 ± 14.8 months for coiling. Complete occlusion was greater in surgery group (80.8%) than endovascular group (21.4%). Re-growth occurred in 2 cases of the coiling group only. Ischemic events were encountered in both groups;silent ones were higher in coiling group (21.4%) than in clipping group (6.3%), while symptomatic ones were higher in the clipping group (49%). Good outcome (mRS 0 - 2) was 51% and 71.4% after clipping and coiling respectively. Postoperative hospital period was longer after clipping (P = 0.04). Conclusions: For anterior circulation ruptured aneurysms, both treatments are feasible, coiling showed lower rate of morbidity while clipping results were better regarding durability and recurrence. Coil embolization may be preferred, which is the current point proved by the RCT like ISAT, but if you choose the patients carefully and find out the optimal candidate for the clipping, the clipping is still enough feasible as a mainstream.展开更多
In this paper, the effect of hot-rolling processing parameters on the post-rolling transformation behavior of C-Mn-Cr-Cu weather-resistant martensitic steel was investigated.Results indicate that the post-rolling tran...In this paper, the effect of hot-rolling processing parameters on the post-rolling transformation behavior of C-Mn-Cr-Cu weather-resistant martensitic steel was investigated.Results indicate that the post-rolling transformation behavior, particularly the post-coiling transformation behavior, strongly depends on the coiling temperature.Under a high coiling temperature, ferrite/pearlite transformation was mainly observed with a low trans-formation speed and transformation dilation after coiling.With decreasing coiling temperature, the proportion of bainite transformation increased with an increased transformation speed and transformation dilation.The dependence of transformation behavior on the coiling temperature could be one of the most important reasons behind the coil collapse of the experimental steel.The optimization of hot-rolling and coiling processing parameters of the steel strip, including laminar flow cooling, coiling temperature, and suspension time on the winding machine, can signi-ficantly reduce the transformation dilation of the steel after hot rolling, thus effectively controlling the coil collapse of the steel.展开更多
A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake(SP)insert no-insulation(NI)coil in a hybrid magnet dur...A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake(SP)insert no-insulation(NI)coil in a hybrid magnet during the charging and discharging processes.The coupled problem is resolved by means of the finite element method(FEM)for the magneto-thermo-elastic behaviors and the Runge-Kutta method for the transient responses of the electrical circuits of the hybrid superconducting magnet system.The results reveal that the transient multi-physics responses of the insert NI coil primarily depend on the charging/discharging procedure of the hybrid magnet.Moreover,a reverse azimuthal current and a compressive hoop stress are induced in the insert NI coil during the charging process,while a forward azimuthal current and a tensile hoop stress are observed during the discharging process.The induced voltages in the insert NI coil can drive the currents flowing across the radial turns where the contact resistance exists.Therefore,it brings forth significant Joule heat,causing a temperature rise and a uniform distribution of this heat in the coil turns.Accordingly,a thermally/mechanically unstable or quenching event may be encountered when a high operating current is flowing in the insert NI coil.It is numerically predicted that a quick charging will induce a compressive hoop stress which may bring a risk of buckling instability in the coil,while a discharging will not.The simulations provide an insight of hybrid superconducting magnets under transient start-up or shutdown phases which are inevitably encountered in practical applications.展开更多
Endovascular coil embolization is a minimally invasive,rapid,and effective method for the treatment of intracranial aneurysms.However,complications associated with coil embolization,such as intraoperative aneurysm rup...Endovascular coil embolization is a minimally invasive,rapid,and effective method for the treatment of intracranial aneurysms.However,complications associated with coil embolization,such as intraoperative aneurysm rupture or arterial occlusion,should be promptly managed during the procedure to avoid catastrophic consequences.This study presents a case of mechanical compression management of the right middle cerebral artery(MCA)inferior trunk during coil embolization for bilateral MCA aneurysms.The inferior trunk of the right MCA was abruptly occluded due to mechanical compression during coil embolization of the right MCA bifurcation aneurysm.A Solitaire AB stent(4×20 mm,Covidien/Medtronic,Dublin,Ireland)was implanted in the inferior trunk of the right MCA after tirofiban was injected via a microcatheter,and the right inferior trunk was recanalized.The patient also underwent coil embolization of the left MCA bifurcation aneurysm,without any complications.It is crucial to recognize compressive occlusion of adjacent aneurysm branches to avoid severe complications during intracranial aneurysm embolization.Stent placement is a rescue treatment option for recanalization of an occluded artery.展开更多
The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order...The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order to improve the life of coiled tubing in high-pressure gas Wells, this paper studies the plugging conditions of coiled tubing in high-pressure ultra-deep Wells. Firstly, the cross section deformation of coiled tubing under high internal pressure is analyzed. Secondly, the factors influencing the fatigue life of coiled tubing and the influence of surface damage on the fatigue life of coiled tubing were studied. Finally, the mechanism of furrow damage caused by coiled tubing and the main measures to reduce furrow damage are analyzed. The following suggestions are made to improve the life of coiled tubing: select the right material and the right size coiled tubing;Use appropriate measures to prevent premature coiled tubing failure and reduce operating costs.展开更多
基金This work was supported by the National Natural Science Foundation of China(grant nos.31270281,32030071)to SQHNNSFC(32071671)to ZYT.
文摘The plant-pollinator‘arms race’model posits that a major driver of the evolution of elongated corollas in flowers is reciprocal selection for‘morphological fit’between pollinator-tongue length and access distance to nectar(usually corolla-tube length).Evidence for the pollinator-mediated selection on tube length and evolution of multiple,correlated floral traits remains inconclusive.To gain possible insights into the strength of stabilizing selection by assessing standing phenotypic variation,we measured a series of functionally important floral traits,including corolla tube length and‘effective’tube depth and degree of style coiling.We then calculated coefficients of variation(CV)for these traits in three field populations of R.schneideriana.Unlike in most long-tubed flowers,the bottom part of the corolla tube is completely occupied by the style,with no room for nectar.The length of this portion of the corolla tube was more variable(higher CV)than the upper part of the corolla tube,suggesting that functional tube depth was under stronger stabilizing selection.The degree of style coiling was negatively related to the corolla-tube length in all three populations of R.schneideriana,suggesting that there may be conflicting selection acting on style length and corolla-tube length,which are otherwise usually tightly correlated.Given the lack of nectar in the flowers of this species,the long corolla tubes and long styles may represent morphological holdovers from ancestors that were pollinated by long-tongued pollinators,as is still seen in related species in the western Himalayas.
基金supported by grants from the National Natural Science Foundation of China,grant no. 81370041, 81771233, 81671655the Outstanding Clinical Discipline Project of Shanghai Pudonggrant no.PWYgy2018-04.
文摘Background:To evaluate the efficacy of stent-assisted coiling(SAC)for the treatment of carotid ophthalmic segment aneurysm segment aneurysms(OSAs)of the internal carotid artery(ICA)through detailed long-term follow-up of a large patient cohort.Methods:We retrospectively analyzed 88 consecutive patients with OSAs between January 2009 and January 2020 at our center.Angiographic results were evaluated using the modified Raymond grading system and clinical outcomes were evaluated using the mRS scale.The primary endpoints were major aneurysm recurrence and poor clinical outcomes for at least 18 months of follow-up.The patients were asked to attend clinical follow-up assessments and possibly undergo DSA or MR via telephone.Results:We enrolled 88 patients with 99 OSAs treated with coiling,of whom 76 were treated with SAC.The coiling procedures were successful in all 88 patients.Overall,complications occurred in 8 patients(9.1%).No procedure-related mortality was observed.67(76.1%)experienced immediate aneurysm occlusion at the end of the procedure.Long-term angiographic follow-up(18 months)was available in 45/88 aneurysms(51%)(average 18.7±5.2 months).Four patients continued their follow-up for 5 years after initial aneurysm treatment.After a clinical follow-up time of 28.7 months(range,12-51 months),85 patients(95.5%)achieved favorable clinical outcomes(mRS scores of 0-2).Conclusions:This study indicates that SAC treatment is a safe and effective therapeutic alternative for ruptured and unruptured OSAs.The procedural risks are low with relatively long-term effectiveness.
基金supported in part by the National Key Research and Development Program of China(No.2022YFA1603402)in part by the National Natural Science Foundation of China(No.11875272)。
文摘Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and serpentine.However,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications difficult.Compared with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical studies.In this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are presented.The analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current density.Then,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.
基金This work is funded by the Magnetic Resonance Union of the Chinese Academy of Sciences(Grant No.2021gzl002)the International Partnership Program of Chinese Academy of Sciences(Grant No.182111KYSB20210014)+1 种基金the National Science Foundation of China(Grant No.52293423,Grant No.52277031)the Research and Development of Key Technologies and Equipment for Major Science and Technology Infrastructure of Development and Reform Commission of Shenzhen Municipality,China(Grant No.ZDKJ20190305002).
文摘The relatively fragile low-temperature stability of cryogen-free superconducting magnetic resonance imaging(MRI)magnets requires the careful management of exogenous heat sources.A strongly shielded gradient magnetic field is important for the optimal operation of cryogen-free MRI systems.In this study,we present an enhanced shielding method incorporating a regionalized stray field constraining strategy.By optimizing the constraint parameters,we could develop engineering-feasible gradient coil schemes without increasing system complexity but with the stray field intensity reduced by half.In real measurement in an integrated MRI system,the developed gradient assembly demonstrated good performance and supported to output images of excellent quality.Our findings suggested that the proposed method could potentially form a useful design paradigm for cryogen-free MRI magnets.
基金supported by the National Key R&D Program of China (2022YFA1603001,2021YFC2801402)the National Nature Science Foundation of China (12073053)the Science and Technology Plan of Inner Mongolia (2021GG0245).
文摘Research on adaptive deformable mirror technology for voice coil actuators(VCAs)is an important trend in the development of large ground-based telescopes.A voice coil adaptive deformable mirror contains a large number of actuators,and there are problems with structural coupling and large temperature increases in their internal coils.Additionally,parameters of the traditional proportional integral derivative(PID)control cannot be adjusted in real-time to adapt to system changes.These problems can be addressed by introducing fuzzy control methods.A table lookup method is adopted to replace real-time calculations of the regular fuzzy controller during the control process,and a prototype platform has been established to verify the effectiveness and robustness of this process.Experimental tests compare the control performance of traditional and fuzzy proportional integral derivative(Fuzzy-PID)controllers,showing that,in system step response tests,the fuzzy control system reduces rise time by 20.25%,decreases overshoot by 78.24%,and shortens settling time by 67.59%.In disturbance rejection experiments,fuzzy control achieves a 46.09%reduction in the maximum deviation,indicating stronger robustness.The Fuzzy-PID controller,based on table lookup,outperforms the standard controller significantly,showing excellent potential for enhancing the dynamic performance and disturbance rejection capability of the voice coil motor actuator system.
基金supported by grant of Changzhou science and technology projects of social development (No. CS2007203)
文摘Prompt diagnosis and therapy of aneurysms are critical for patients with nontraumatic subarachnoid hemorrhage (SAH).The aim of our study was to assess the clinical usefulness of multislice computed tomography angiography (CTA) in the surgical and endovascular treatment of intracranial aneurysms.A total of 195 cases with 206 intracranial aneurysms underwent CTA.Fifty (24%) aneurysms underwent surgical clipping while 156 (76%) aneurysms underwent endovascular coiling.In the five missed aneurysms at digital substraction angiography and the nine aneurysms with mass intracerebral hematomas,surgical treatment was successfully performed based on 16-slice CTA alone,and the other 36 aneurysms were clipped on the main basis of the CTA.The intraoperative findings correlated well with the CTA findings and all aneurysms were clipped successfully.Sixteen-slice CTA image information has been shown to determine the choice of aneurysm therapy and assist the surgical and endovascular treatment of intracranial aneurysms.
文摘Objective:This study aimed to evaluate the clinical and angiographic outcomes of aneurysms that were completely or near-completely embolized and ascertain whether complete embolization is important in the stent-assisted coiling(SAC)of intracranial aneurysms.Methods:This retrospective study enrolled 390 patients(417 aneurysms).Among them,complete(100%)or nearcomplete(>90%)angiographic obliteration of the aneurysms on immediate angiography was accomplished.Baseline characteristics,complications,angiography follow-up results,and clinical outcomes were analyzed.Results:Cumulative adverse events occurred in 30 patients(7.7%),including thromboembolic complications in 17(4.4%),intraoperative rupture in 10(2.6%),and others in 3(0.8%).Statistical analyses revealed an increased intraprocedural rupture rate in the initial completely occluded aneurysms(5.6%compared with 1.0%).The incidence of cumulative adverse events was higher in patients with completely occluded aneurysms(11.1%)than in those with near-completely occluded aneurysms(5.5%).Angiography follow-up was available for 173 aneurysms.Aneurysm occlusion status at follow-up was correlated with stent placement(p?0.000,odds ratio?5.847),size(p?0.000,odds ratio?6.446 for tiny aneurysms;and p?0.001,odds ratio?5.616 for small aneurysms),and initial aneurysm occlusion status(p?0.001,odds ratio?3.436).Complete occlusion at followup was seen in 82.6%of the initial complete occlusion group versus 63.0%of the initial near-complete occlusion group.The incidence of complete occlusion at follow-up was higher in the initial completely occluded aneurysms with SAC(100%)than in the initial completely occluded aneurysms with non-SAC(65.2%).Conclusions:Initial complete treatment may lead to higher complication rates and good clinical outcomes at follow-up.Stent placement may enhance progressive aneurysm occlusion.Initial complete occlusion with SAC can provide durable closure at follow-up.
文摘A new intelligent control scheme for hot strip coiling temperature is presented. In this scheme, the prediction mode1 of finishing temperature and the presetting model of main cooling zone are establish based on BP neural network, the feed-forward open-loop control model of main cooling zone is constructed based on T-S fuzzy neural network, a new improved structure of T-S fuzzy neural network is developed, and the feedback close-loop control model of precision cooling zone is obtained based on fuzzy control. The effectiveness of the proposed scheme has been demonstrated by computer simulation with a satisfactory result.
基金Funded by the National Natural Science Foundation of China(No.51501056)Natural Science Foundation of Hebei Province(No.E2016209341)+2 种基金Educational Commission of Hebei Province(No.BJ2014031)Project of Science and Technology of Tangshan(Nos.14130243B and 15130202C)Foundation of North China University of Science and Technology(No.JP201510)
文摘The effects of hot-strip coiling temperature on Ti(C,N) precipitation, texture and hydrogen permeation behavior in DC06 EK enamel steel were investigated by TEM, EBSD test and electrochemical hydrogen permeation experiment. It was found that the Ti(C,N) particles in hot-strip coarsened with increasing coiling temperature, whereas after cold-rolling and annealing, the size difference of Ti(C,N) particles was lessened. The hot-strip coiling temperature has a significant impact on the recrystallized texture in the subsequent cold-rolled and annealed sheet. Hot-strip using high temperature(700 ℃) coiling leads to strong {111} recrystallized texture in annealed sheet, with peak intensity 9.2. On the contrary, in annealed sheets using hot-strip coiling at 650 ℃, their {111} recrystallized textures were weaker, which was also reflected in their rmvalues. Even though the hydrogen diffusion coefficient is slightly lower(7.76×10^(-5) mm^2/s) in annealed sheet using low temperature coiling(600 ℃), appropriately higher coiling temperature is more suitable for DC06 EK enamel steel combining both good drawability and fish-scale resistance.
文摘The effects of cooling rate and coiling temperature on microstructure and mechanical properties of a plain carbon steel were investigated by combining metallography and tensile experiments. The results indicate that ferrite grain size is refined and bainite transformation occurs to ensure high strength and elongation, as the cooling rate is quick enough. Yield strength and tensite strength improve with the decreased finish cooling temperature, but the elongation decreases too significantly to meet the requirements. Thus, the cooling rate must be quick enough, and the appropriate coiling temperature should be carefully selected to obtain refined ferrite and a small amount of bainite to improve the strength while the plasticity is also ensured. Under this condition, the Mn element concentration can be reduced to save cost or produce higher strength steel with same chemical composition.
文摘To improve the precision of the coiling temperature and the performance of the feedback control system with long pure time delay on hot strip mills, we analyzed the design process of the Dahlin algorithm in detail. The coiling temperature curves controlled by the PID algorithm and Dahlin algorithm were simulated and compared, which showed that the control precision with the Dahlin algorithm was higher than that with the PID algorithm. That was further verified by the production practice.
文摘A measure called the Uncertainty in Unruptured Intracranial Aneurysm Patients Undergoing Endovascular Coiling Scale (UUIACS) was developed and its validity and reliability were examined. The 49 questions that comprised the original draft of the UUIACS were created based on interview data. Based on data from 172 participants, exploratory and confirmatory factor analyses were conducted. As a result of exploratory factor analysis, the UUIACS e retained 17 items and extracted four factors (“Lack of decision-making cues”, “Lack of information and complexity of information interpretation”, “The ambiguous nature of the disease”, and “The unpredictable living with UIA”). All of the UUIACS items showed adequate internal consistency. Between the UUIAC scale and the Universal Uncertainty in Illness Scale (UUIS), the Health Locus of Control (HLC) scale, and the SF-36v2® (Japanese version), positive correlations were found between the UUIACS and UUIS, and the HLC scale at a 1% significance level indicating concurrent validity. According to confirmatory factor analysis, the UUIACS had an acceptable goodness of fit. Given these findings, the UUIACS was judged to have satisfied the criteria for use in a clinical setting, although further investigation was required.
文摘Background: Potentially lethal, aneurysmal subarachnoid hemorrhage has a bad prognosis for many individuals. Over the past few decades, endovascular and surgical interventions have been developed, including surgical clipping, and endovascular coiling. Patients who have aSAH are also susceptible to delayed cerebral ischemia and cerebral vasospasm. The aim of this study is to compare the outcome of endovascular coiling with surgical clipping in patients with SAH, specifically in relation to prevalence of vasospasm, in the country of Georgia. Method: In this study, we present a retrospective review of the outcomes of 217 patients with acute subarachnoid hemorrhage who underwent endovascular coiling or surgical clipping. The data were gathered from patients who are admitted to New Vision University Hospital and Caucasus Medical Center in Tbilisi, Georgia, between 2017 and 2022. Results: Vasospasm was prevalent in 217 of the patients who had aneurysmal rupture when they first appeared. Endovascular coiling or surgical clipping was used to treat aneurysmal rupture. In our sample, 24.81 percent of patients who underwent coiling experienced vasospasm after 14 days, compared to 31.25 percent of patients who underwent clipping. After endovascular coiling and surgical clipping, the severity of vasospasm was only slightly different, according to Lindegaard ratios. Finally, 32 patients (23.35 percent) died after coiling whereas 55 patients (68.75 percent) died within three decades of clipping. Conclusion: After 5 years of data collection, this study has demonstrated the most favorable option for treatment is endovascular coiling. However, the treatment choice takes multiple factors into account, and clipping is not ideal for some ruptured aneurysms. Despite the fact that endovascular coiling is usually successful and minimally invasive, complications can occur and additional monitoring and potential surgical intervention are indicated.
文摘Objective: To evaluate and compare the outcomes of microsurgical clipping and endovascular coiling of ruptured anterior cerebral circulation aneurysms. Methods: The current study retrospectively included 61 patients presented with subarachnoid hemorrhage (SAH), treated by clipping or coiling for ruptured aneurysms located in anterior circulation. Anatomic outcome and post-operative ischemic events were evaluated. The primary clinical outcomes were evaluated as operative complications while the secondary clinical outcome was evaluated by modified Rankin scale (mRS) at discharge. Results: Of 61 ruptured aneurysms, 47 and 14 were treated by surgery and coiling, respectively. The average follow-up duration was 19.1 ± 18.6 months for clipping and 21.7 ± 14.8 months for coiling. Complete occlusion was greater in surgery group (80.8%) than endovascular group (21.4%). Re-growth occurred in 2 cases of the coiling group only. Ischemic events were encountered in both groups;silent ones were higher in coiling group (21.4%) than in clipping group (6.3%), while symptomatic ones were higher in the clipping group (49%). Good outcome (mRS 0 - 2) was 51% and 71.4% after clipping and coiling respectively. Postoperative hospital period was longer after clipping (P = 0.04). Conclusions: For anterior circulation ruptured aneurysms, both treatments are feasible, coiling showed lower rate of morbidity while clipping results were better regarding durability and recurrence. Coil embolization may be preferred, which is the current point proved by the RCT like ISAT, but if you choose the patients carefully and find out the optimal candidate for the clipping, the clipping is still enough feasible as a mainstream.
文摘In this paper, the effect of hot-rolling processing parameters on the post-rolling transformation behavior of C-Mn-Cr-Cu weather-resistant martensitic steel was investigated.Results indicate that the post-rolling transformation behavior, particularly the post-coiling transformation behavior, strongly depends on the coiling temperature.Under a high coiling temperature, ferrite/pearlite transformation was mainly observed with a low trans-formation speed and transformation dilation after coiling.With decreasing coiling temperature, the proportion of bainite transformation increased with an increased transformation speed and transformation dilation.The dependence of transformation behavior on the coiling temperature could be one of the most important reasons behind the coil collapse of the experimental steel.The optimization of hot-rolling and coiling processing parameters of the steel strip, including laminar flow cooling, coiling temperature, and suspension time on the winding machine, can signi-ficantly reduce the transformation dilation of the steel after hot rolling, thus effectively controlling the coil collapse of the steel.
基金the National Natural Science Foundation of China(Nos.11932008 and 11672120)the Fundamental Research Funds for the Central Universities of China(No.lzujbky-2022-kb01)。
文摘A transient multi-physics model incorporated with an electromagneto-thermomechanical coupling is developed to capture the multi-field behavior of a single-pancake(SP)insert no-insulation(NI)coil in a hybrid magnet during the charging and discharging processes.The coupled problem is resolved by means of the finite element method(FEM)for the magneto-thermo-elastic behaviors and the Runge-Kutta method for the transient responses of the electrical circuits of the hybrid superconducting magnet system.The results reveal that the transient multi-physics responses of the insert NI coil primarily depend on the charging/discharging procedure of the hybrid magnet.Moreover,a reverse azimuthal current and a compressive hoop stress are induced in the insert NI coil during the charging process,while a forward azimuthal current and a tensile hoop stress are observed during the discharging process.The induced voltages in the insert NI coil can drive the currents flowing across the radial turns where the contact resistance exists.Therefore,it brings forth significant Joule heat,causing a temperature rise and a uniform distribution of this heat in the coil turns.Accordingly,a thermally/mechanically unstable or quenching event may be encountered when a high operating current is flowing in the insert NI coil.It is numerically predicted that a quick charging will induce a compressive hoop stress which may bring a risk of buckling instability in the coil,while a discharging will not.The simulations provide an insight of hybrid superconducting magnets under transient start-up or shutdown phases which are inevitably encountered in practical applications.
基金supported by the Construction Project of the Stroke Center of the Fengxian District,Shanghai(2017-118).
文摘Endovascular coil embolization is a minimally invasive,rapid,and effective method for the treatment of intracranial aneurysms.However,complications associated with coil embolization,such as intraoperative aneurysm rupture or arterial occlusion,should be promptly managed during the procedure to avoid catastrophic consequences.This study presents a case of mechanical compression management of the right middle cerebral artery(MCA)inferior trunk during coil embolization for bilateral MCA aneurysms.The inferior trunk of the right MCA was abruptly occluded due to mechanical compression during coil embolization of the right MCA bifurcation aneurysm.A Solitaire AB stent(4×20 mm,Covidien/Medtronic,Dublin,Ireland)was implanted in the inferior trunk of the right MCA after tirofiban was injected via a microcatheter,and the right inferior trunk was recanalized.The patient also underwent coil embolization of the left MCA bifurcation aneurysm,without any complications.It is crucial to recognize compressive occlusion of adjacent aneurysm branches to avoid severe complications during intracranial aneurysm embolization.Stent placement is a rescue treatment option for recanalization of an occluded artery.
文摘The coiled tubing plugging has become the main means of plugging in gas Wells in Xinjiang. These Wells are deep and have high pressure, which can easily affect the fatigue life of the operating coiled tubing. In order to improve the life of coiled tubing in high-pressure gas Wells, this paper studies the plugging conditions of coiled tubing in high-pressure ultra-deep Wells. Firstly, the cross section deformation of coiled tubing under high internal pressure is analyzed. Secondly, the factors influencing the fatigue life of coiled tubing and the influence of surface damage on the fatigue life of coiled tubing were studied. Finally, the mechanism of furrow damage caused by coiled tubing and the main measures to reduce furrow damage are analyzed. The following suggestions are made to improve the life of coiled tubing: select the right material and the right size coiled tubing;Use appropriate measures to prevent premature coiled tubing failure and reduce operating costs.