The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source conv...The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source converter(LCC-VSC)power grids are one of the more important developmental directions of the future power grid that have occured in recent years.But the multi-terminal high voltage direct current system has the problems of inconsistent boundary characteristics,inconsistent control,and fault response characteristics,which puts higher requirements on the protection scheme.Thus,a completely new protection principle is proposed in this paper.Firstly,the fault characteristics of distributed capacitance current are analyzed.The reactive power calculated by the distribution parameters of different frequencies is different.Subsequently,the fault characteristics of DC reactive power are analyzed,and a DC reactive power extraction algorithm is proposed.The polarity of the multi-band DC reactive power is used to construct the protection scheme.Finally,the LCC-VSC power grid model verifies the correctness and superiority of the proposed protection scheme.The proposed scheme uses DC reactive power instead of fault current to solve the long delay problem caused by distributed capacitance.Compared with the prior art,the proposed solution is not affected by distributed capacitance and has a stronger anti-interference ability(600Ω+10 dB+1 ms).展开更多
AIM:To determine the factors related to preoperative ocular characters that are predictive of insufficient vault(<250μm)after implantable collamer lens(ICL V4c;STAAR Surgical)implantation.METHODS:The participants ...AIM:To determine the factors related to preoperative ocular characters that are predictive of insufficient vault(<250μm)after implantable collamer lens(ICL V4c;STAAR Surgical)implantation.METHODS:The participants underwent ICL surgery and were divided into the low(<250μm)and normal(250-1000μm)vault groups based on the postoperative vault at 3mo.The preoperative biometric parameters and clinical outcomes were compared between the two groups.The relationship between the 3-month vault values and preoperative ocular parameters were evaluated by Generalized estimating equations.RESULTS:Sixteen(23 eyes)and 36 patients(63 eyes)were in the low and normal vault groups,respectively.All implantation procedures were uneventful with no cataract formation in the early postoperative period.The sulcusto-sulcus lens rise(STSL)and iris ciliary angle(ICA)were correlated with vault at 3mo after surgery.Every 0.1 mm increase in STSL was associated with 38.9μm decrease in the postoperative 3-month vault.A rise of 1 degree in ICA is associated with a reduction of 4μm in vault.CONCLUSION:Eyes with a narrow ciliary sulcus are associated with a higher rate of low vault after ICL implantation,suggesting a need for adjustments to the ICL size in these patients.Evaluating the characteristics of the ciliary sulcus contributes valuable information to predict low vault after surgery.展开更多
AIM:To analyze ultrasound biomicroscopy(UBM)images using random forest network to find new features to make predictions about vault after implantable collamer lens(ICL)implantation.METHODS:A total of 450 UBM images we...AIM:To analyze ultrasound biomicroscopy(UBM)images using random forest network to find new features to make predictions about vault after implantable collamer lens(ICL)implantation.METHODS:A total of 450 UBM images were collected from the Lixiang Eye Hospital to provide the patient’s preoperative parameters as well as the vault of the ICL after implantation.The vault was set as the prediction target,and the input elements were mainly ciliary sulcus shape parameters,which included 6 angular parameters,2 area parameters,and 2 parameters,distance between ciliary sulci,and anterior chamber height.A random forest regression model was applied to predict the vault,with the number of base estimators(n_estimators)of 2000,the maximum tree depth(max_depth)of 17,the number of tree features(max_features)of Auto,and the random state(random_state)of 40.0.RESULTS:Among the parameters selected in this study,the distance between ciliary sulci had a greater importance proportion,reaching 52%before parameter optimization is performed,and other features had less influence,with an importance proportion of about 5%.The importance of the distance between the ciliary sulci increased to 53% after parameter optimization,and the importance of angle 3 and area 1 increased to 5% and 8%respectively,while the importance of the other parameters remained unchanged,and the distance between the ciliary sulci was considered the most important feature.Other features,although they accounted for a relatively small proportion,also had an impact on the vault prediction.After parameter optimization,the best prediction results were obtained,with a predicted mean value of 763.688μm and an actual mean value of 776.9304μm.The R²was 0.4456 and the root mean square error was 201.5166.CONCLUSION:A study based on UBM images using random forest network can be performed for prediction of the vault after ICL implantation and can provide some reference for ICL size selection.展开更多
Dear Editor,We are writing this letter to report two unusual cases of femtosecond laser-assisted cataract surgery(FLACS)in two ICL-implanted patients with significant different vault.FLACS has been confirmed by accumu...Dear Editor,We are writing this letter to report two unusual cases of femtosecond laser-assisted cataract surgery(FLACS)in two ICL-implanted patients with significant different vault.FLACS has been confirmed by accumulating evidence to improve the safety and precision of surgery from common cases to complicated cases in treating cataracts[1-3].Implantable collamer lens(ICL)implantation possesses a good performance in its predictability,reversibility,and the rapid visual recovery.展开更多
The bone defects of the cranial vault encompassed rare malformations including acalvaria, hypocalvaria, acrania, hypocrania, anencephaly and exencephaly. They are also described in some pathological entities such as a...The bone defects of the cranial vault encompassed rare malformations including acalvaria, hypocalvaria, acrania, hypocrania, anencephaly and exencephaly. They are also described in some pathological entities such as aplasia cutis congenita of the scalp. We report an unusual case of cephalic malformation which combine defects of the skin, the dura mater, and the bones of the vault, with a malformation of the central nervous system. This unique case emphasizes a problem of nosological definition between the terms mentioned above. acalvaria, the acrania, the hypocalvaria and the aplasia cutis congenita. Thus, herein, we proceed to a literature review of bone defects of the skull and their differential diagnosis.展开更多
基金supported by the National Natural Science Foundation of China-State Grid Joint Fund for Smart Grid(No.U2066210).
文摘The DC grid technology of multi-power supply and multi-drop-point power reception is an effective solution for large-scale renewable energy integration into the power grid.Line-commutated converter-Voltage source converter(LCC-VSC)power grids are one of the more important developmental directions of the future power grid that have occured in recent years.But the multi-terminal high voltage direct current system has the problems of inconsistent boundary characteristics,inconsistent control,and fault response characteristics,which puts higher requirements on the protection scheme.Thus,a completely new protection principle is proposed in this paper.Firstly,the fault characteristics of distributed capacitance current are analyzed.The reactive power calculated by the distribution parameters of different frequencies is different.Subsequently,the fault characteristics of DC reactive power are analyzed,and a DC reactive power extraction algorithm is proposed.The polarity of the multi-band DC reactive power is used to construct the protection scheme.Finally,the LCC-VSC power grid model verifies the correctness and superiority of the proposed protection scheme.The proposed scheme uses DC reactive power instead of fault current to solve the long delay problem caused by distributed capacitance.Compared with the prior art,the proposed solution is not affected by distributed capacitance and has a stronger anti-interference ability(600Ω+10 dB+1 ms).
基金Supported by National Natural Science Foundation of China(No.81900910)Natural Science Foundation of Zhejiang Province(No.LQ19H120003)Basic Scientific Research Project of Wenzhou(No.Y2023809).
文摘AIM:To determine the factors related to preoperative ocular characters that are predictive of insufficient vault(<250μm)after implantable collamer lens(ICL V4c;STAAR Surgical)implantation.METHODS:The participants underwent ICL surgery and were divided into the low(<250μm)and normal(250-1000μm)vault groups based on the postoperative vault at 3mo.The preoperative biometric parameters and clinical outcomes were compared between the two groups.The relationship between the 3-month vault values and preoperative ocular parameters were evaluated by Generalized estimating equations.RESULTS:Sixteen(23 eyes)and 36 patients(63 eyes)were in the low and normal vault groups,respectively.All implantation procedures were uneventful with no cataract formation in the early postoperative period.The sulcusto-sulcus lens rise(STSL)and iris ciliary angle(ICA)were correlated with vault at 3mo after surgery.Every 0.1 mm increase in STSL was associated with 38.9μm decrease in the postoperative 3-month vault.A rise of 1 degree in ICA is associated with a reduction of 4μm in vault.CONCLUSION:Eyes with a narrow ciliary sulcus are associated with a higher rate of low vault after ICL implantation,suggesting a need for adjustments to the ICL size in these patients.Evaluating the characteristics of the ciliary sulcus contributes valuable information to predict low vault after surgery.
文摘AIM:To analyze ultrasound biomicroscopy(UBM)images using random forest network to find new features to make predictions about vault after implantable collamer lens(ICL)implantation.METHODS:A total of 450 UBM images were collected from the Lixiang Eye Hospital to provide the patient’s preoperative parameters as well as the vault of the ICL after implantation.The vault was set as the prediction target,and the input elements were mainly ciliary sulcus shape parameters,which included 6 angular parameters,2 area parameters,and 2 parameters,distance between ciliary sulci,and anterior chamber height.A random forest regression model was applied to predict the vault,with the number of base estimators(n_estimators)of 2000,the maximum tree depth(max_depth)of 17,the number of tree features(max_features)of Auto,and the random state(random_state)of 40.0.RESULTS:Among the parameters selected in this study,the distance between ciliary sulci had a greater importance proportion,reaching 52%before parameter optimization is performed,and other features had less influence,with an importance proportion of about 5%.The importance of the distance between the ciliary sulci increased to 53% after parameter optimization,and the importance of angle 3 and area 1 increased to 5% and 8%respectively,while the importance of the other parameters remained unchanged,and the distance between the ciliary sulci was considered the most important feature.Other features,although they accounted for a relatively small proportion,also had an impact on the vault prediction.After parameter optimization,the best prediction results were obtained,with a predicted mean value of 763.688μm and an actual mean value of 776.9304μm.The R²was 0.4456 and the root mean square error was 201.5166.CONCLUSION:A study based on UBM images using random forest network can be performed for prediction of the vault after ICL implantation and can provide some reference for ICL size selection.
基金Supported by Key Research and Development Program of Shaanxi Province(No.2020SF-271,No.2017SF-273)。
文摘Dear Editor,We are writing this letter to report two unusual cases of femtosecond laser-assisted cataract surgery(FLACS)in two ICL-implanted patients with significant different vault.FLACS has been confirmed by accumulating evidence to improve the safety and precision of surgery from common cases to complicated cases in treating cataracts[1-3].Implantable collamer lens(ICL)implantation possesses a good performance in its predictability,reversibility,and the rapid visual recovery.
文摘The bone defects of the cranial vault encompassed rare malformations including acalvaria, hypocalvaria, acrania, hypocrania, anencephaly and exencephaly. They are also described in some pathological entities such as aplasia cutis congenita of the scalp. We report an unusual case of cephalic malformation which combine defects of the skin, the dura mater, and the bones of the vault, with a malformation of the central nervous system. This unique case emphasizes a problem of nosological definition between the terms mentioned above. acalvaria, the acrania, the hypocalvaria and the aplasia cutis congenita. Thus, herein, we proceed to a literature review of bone defects of the skull and their differential diagnosis.
