Effects of wind guide plates on wind velocity acceleration and dune leveling： a case study in Ulan Buh Desert, China

The areas used to be covered by shifting sand dunes have been reclaimed rapidly in recent years. However, it is a challenge to reclaim high sand dunes because it is rather costly to level the high dunes to gentle arable lands. In this study, a wind guide plate was used to change the characteristics of natural wind to level the sand dunes. The use of wind energy could significantly increase the efficiency of dune leveling and decrease the cost. Low wind velocity is a typical characteristic in Ulan Buh Desert of China where the average wind speed is much lower than the threshold velocity for sand movement. The experiment of this study was conducted to accelerate the wind velocity by a wind guide plate to level a sand dune. Results show that the threshold velocity for sand movement is 3.32 m/s at 10 cm above the sand surface in Ulan Buh Desert. A wind guide plate set at an angle less than 50° could significantly increase the wind velocity. The wind velocity could be accelerated up to the threshold velocity for sand movement behind a plate when the plate is at the angles of 20°, 25°, 35° and 40°. The most significant acceleration of wind velocity appears at 1.5 and 3.0 m behind the plate with an angle of 25°. An obvious wind velocity acceleration zone exists behind the wind guide plate when the angles are at 25°, 35°, 40° and 45°, with the most obvious zone under the angle of 45°. The results also show that the total amount of sand transferred over the experimental period increased by 6.1% under the effects of wind guide plates compared to the sand moved without wind guide plates. The results of the study will provide theoretical and practical supports for desert management in sand dune areas.

Orthodontic treatment combined with 3D printing guide plate implant restoration for edentulism and its influence on mastication and phonic function

BACKGROUND Dentition defect,a common clinical oral disease developed in humans,not only causes masticatory dysfunction and articulation difficulties but also affects facial appearance and increases the burden on the intestinal tract.Restorative treatment is the primary option for this disease.However,traditional restorations have many drawbacks,such as mismatch with the body,low reliability,and incomplete occlusal function recovery.AIM to analyze the efficacy of orthodontics combined with 3D printing guide plate implant restoration in treating patients with dentition defects and its influence on masticatory and phonic functions.METHODS A prospective study was carried out in 86 patients with dentition defects who received implant prosthesis after orthodontic treatment in our hospital between January 2018 and January 2019.Those patients were divided into a control group and an intervention group with 43 patients in each group using a random number table.The control group received traditional implant restoration,whereas the intervention group received 3D printing guide plate implant restoration.Treatment outcomes,cosmetic appearance,dental function,implant deviation,and quality of life were compared between the two groups.RESULTS The overall response rate in the intervention group was significantly higher than that in the control group(95.35%vs 81.40%,χ^(2)=4.071,P=0.044).The number of cases with neatly trimmed cosmetic appearance(χ^(2)=4.497,P=0.034),complete coverage(χ^(2)=4.170,P=0.041),and normal occlusion(χ^(2)=5.512,P=0.019)in the intervention group was higher than that in the control group.After treatment,mastication,swallowing,and articulation were significantly improved in both groups.Masticatory(t=2.980,P=0.004),swallowing(t=2.199,P=0.031),and phonic functions(t=3.950,P=0.004)were better in the intervention group than those in the control group.The deviation value and the deviation angle(t=5.440,P=0.000)at the top(t=6.320,P=0.000)and middle parts of the implants(t=22.295,P=0.000)in the intervention group were lower than those in the control group after treatment.Functional limitations,psychosocial and physical pain and discomfort,and total scores decreased in both groups.The functional limitation(t=2.379,P=0.020),psychosocial(t=2.420,P=0.000),physical pain and discomfort(t=6.581,P=0.000),and total scores(t=2.140,P=0.035)were lower in the intervention group than those in the control group.CONCLUSION Orthodontic treatment combined with 3D printing guide plate implant restoration can significantly improve the masticatory and phonic functions,quality of life,and psychological health of patients with dentition defects.Therefore,it is highly recommended in clinic application.

Three-Dimensional Scattering of an Incident Plane Shear Horizontal Guided Wave by a Partly through-Thickness Hole in a Plate

We investigate the three-dimensional （3D） scattering problem of an incident plane shear horizontal wave by a partly through-thickness hole in an isotropic plate, in which the Lamb wave modes are also included due to the mode conversions by the scattering obstacle in the 3D problem. An analytical model is presented such that the wave fields are expanded in all of propagating and evanescent SH modes and Lamb modes, and the scattered far-fields of three fundamental guided wave modes are analyzed numerically for different sizes of the holes and frequencies. The numerical results are verified by comparing with those obtained by using the approximate Poisson/Mindlin plate model for small hole radius and low frequency. It is also found that the scattering patterns are different from those of the SO wave incidence. Our work is useful for quantitative evaluation of the plate-like structure by ultrasonic guided waves.

Rib and Groove Type Wind Guide Plate Analysis for Wind Power System

This research is the analysis of rib and groove type wind guide plate for wind generation power system. This device generates electricity by the air flow producing by the high-speed vehicles driving on the road. It can produce electricity as long as there are car passing on the high way. The effect is much more efficient in heavy traffic with high speed. If we can set up a large number of this system along the highway, it can provide the lighting in the highway at night but also sell the extra electricity to the power companies with low cost, high performances and improvement of environmental benefits.

Design of New Elevator Pressure Guide Plate and Its Test Device

Pressure guide plate plays a certain role in the safe operation of elevator.Based on understanding the respective performance of new and old pressure guide plates,this paper analyses the problems existing in the original pressure guide plate.It also conducts stress analysis according to the function of pressure guide plate on elevator,and designs a new type of pressure guide plate combined with technological capability and equipment.According to the stress characteristics,a test device is designed and a comparative test is made between the new type of pressure guide plate and the old in order to test the reliability of the new type of pressure guide plate.The test proves that the new pressure guide plate of elevator can meet the requirements of product use and safe operation of elevator products.

4-20 Electrons Guiding through a Plate Capillary

The guiding effect of 3 keV Ne7+ ions passing through an insulating PET nanocapillaries was found in 2002by N. Stolterfoht et al[1]. Since then considerable work[2] has been done to investigate slow highly charged ions(HCIs) interacting with inner surfaces of various insulating capillaries. It has been shown that the guiding effect isprevalent in the transmission of slow HCIs.Similar guiding phenomena were also observed for electrons transmitted through capillaries (see, e.g., Ref. [3-5]).However, the experiments showed that transmission efficiency of electrons was significantly lower than that of HCIs.Moreover, it revealed that portion of the transmitted electrons suffered significant energy-loss.

数字化精准全膝关节置换与传统置换方法的短期效果对比

背景:传统全膝关节置换手术在术前的准备有限,作者提出基于计算机仿真和3D打印技术的数字化精准全膝置换方法,旨在通过充分的术前设计来提升置换效果。目的:利用计算机仿真和个性化手术导板建立数字化精准全膝关节置换方法,比较新方法和传统方法的临床效果。方法:回顾性分析97例全膝关节置换患者的临床资料,根据手术方法将患者分为2组,对照组(n=48)采取传统方式进行全膝关节置换手术,使用传统胶片模板;观察组(n=49)采用数字化精准全膝置换方法进行手术,使用计算机辅助技术选定假体尺寸型号。比较两组患者的手术时间、术中出血量、术前及术后美国特种外科医院膝关节评分以及股骨力线和膝关节面线夹角和胫骨角、髋膝踝角与标准角度的差值。结果与结论:(1)两组患者术前性别、年龄、体质量指数、美国特种外科医院膝关节评分,以及胫骨角、股骨力线和膝关节面线夹角、髋膝踝角与标准角度的差值相比差异均无显著性意义(P> 0.05);(2)与对照组比较,观察组手术时间缩短、出血量减少;两组术后3个月膝关节美国特种外科医院膝关节评分对比术前均显著升高(P> 0.05),且术后3个月观察组评分高于对照组(P> 0.05);(3)两组之间胫骨角、股骨力线和膝关节面线夹角、髋膝踝角与标准角度的差值相比差异均有显著性意义,观察组优于对照组(P <0.05);(4)观察组股骨假体预测准确率为94%,对照组为58%;胫骨假体预测准确率为96%,对照组为62%;(5)提示数字化精准全膝关节置换相较传统全膝关节置换的手术时间更短、出血量更少、术后膝关节功能评分和力线恢复更好,具有良好的短期临床效果。

Guided Waves in the Multilayered One-Dimensional Hexagonal Quasi-crystal Plates

Guided waves in the multilayered one-dimensional quasi-crystal plates are,respectively,investigated in the context of the Bak and elasto-hydrodynamic models.Dispersion curves and phonon and phason displacements are calculated using the Legendre polynomial method.Wave characteristics in the context of these two models are analyzed in detail.Results show that the phonon-phason coupling effects on the first two layers are the same at low frequencies;but,they are more significant on the first layer than those on the second layer at high frequencies.These obtained results lay the theoretical basis of guided-wave nondestructive test on multilayered quasi-crystal plates.

GUIDED THERMOELASTIC WAVE PROPAGATION IN LAYERED PLATES WITHOUT ENERGY DISSIPATION

In this paper, the propagation of guided thermoelastic waves in laminated orthotropic plates subjected to stress-free, isothermal boundary conditions is investigated in the context of the Green-Naghdi （GN） generalized thermoelastic theory （without energy dissipation）. The coupled wave equations and heat conduction equation are solved by the Legendre orthogonal polynomial series expansion approach. The validity of the method is confirmed through a comparison. The dispersion curves of thermal modes and elastic modes are illustrated simultaneously. Dispersion curves of the corresponding pure elastic plate are also shown to analyze the influence of the thermoelasticity on elastic modes. The displacement and temperature distributions are shown to discuss the differences between the elastic modes and thermal modes.

Combined distal tibial rotational osteotomy and proximal growth plate modulation for treatment of infantile Blount's disease

Infantile Blount's disease is a condition that causes genu varum and internal tibial torsion. Treatment options include observation, orthotics, corrective osteotomy, elevation of the medial tibial plateau, resection of a physeal bar, lateral hemi-epiphysiodesis, and guided growth of the proximal tibial physis. Each of these treatment options has its disadvantages. Treating the coronal deformity alone(genu varum) will result in persistence of the internal tibial torsion(the axial deformity). In this report, we describe the combination of lateral growth modulation and distal tibial external rotation osteotomy to correct all the elements of the disease. This has not been described before for treatment of Blount's disease. Both coronal and axial deformities were corrected in this patient. We propose this combination(rather than the lateral growth modulation alone) as the method of treatment for early stages of Blount's disease as it corrects both elements of the disease and in the same time avoids the complications of proximal tibial osteotomy.

3D打印导板定位微球囊压迫术治疗原发性三叉神经痛的临床随机对照研究

目的 分析3D打印导板定位微球囊压迫术(PMC)与常规PMC治疗原发性三叉神经痛(PTN)的临床疗效及安全性。方法 选择廊坊市人民医院神经外科2020年1月—2022年12月收治的80例PTN患者作为研究对象,使用随机数字表法分成观察组与对照组各40例。对照组行常规PMC治疗,观察组行3D打印导板定位PMC治疗。比较两组手术一般情况、术后即刻疗效、手术前后不同时点疼痛视觉模拟量表(VAS)评分、术后12个月复发情况及术后并发症情况。结果 观察组首次穿刺成功率97.50%显著高于对照组27.50%(P<0.05)。观察组穿刺成功时间、手术总时间、住院时间、住院费用均显著优于对照组(P<0.05)。观察组术后即刻总有效率97.50%与对照组95.00%比较,差异无统计学意义(P>0.05)。两组术前及术后1、2周的VAS评分组间比较(P>0.05)显示,观察组术后4周时疼痛VAS评分显著低于同期对照组(P<0.05)。术后12个月,观察组合计复发率5.00%显著低于对照组合计复发率20.00%(P<0.05)。观察组术后面部麻木、咬肌无力、口唇疱疹发生率与对照组比较,差异无统计学意义(P>0.05)。结论 3D打印导板定位PMC较常规PMC能显著提高首次穿刺成功率,缩短穿刺时间与手术总时间,且术后即刻疗效及远期疗效均显著。

汽车激光雷达盖板的双色注塑模具设计

根据某车型激光雷达盖板的双色结构及形状,采用动模型芯旋转式结构的模具方案,设计了一套一出二的热流道双色注塑模具。利用Moldflow软件进行了双色成型分析,双色注塑第一次注射成型透明的PMMA材料的产品,第二次注射成型黑色ASA材料的产品。为实现该双色产品的结构成型,在定模处设计了2组不同结构的型腔,在动模处设计了2组左右对称的型芯,并且,在型芯侧设计了双斜导柱抽芯机构,冷却系统设计为“直通式+隔水片”的随形循环水路;顶出系统设计为2组独立的液压油缸,在产品顶出取件中,第一次注射成型的PMMA产品不顶出,第二次注射成型的ASA材料的产品采用“直顶+斜顶”的组合机构将双色产品推出,最终通过机械手完成产品的取件。实践生产证明了该双色模具结构合理、运行稳定、成型的双色塑件表面无缺陷。

打印机滚筒导板多点浇口注塑模设计

针对打印机滚筒导板塑件的工业设计结构特点及使用改性合金聚碳酸酯/丙烯腈-丁二烯-苯乙烯塑料成型的生产要求,设计了一副多点点浇口三板模具用于该塑件的注射成型。模具中的模腔布局为一模一腔,以使塑件成型精度控制在MT3~4级。不同于常规三板模具,在该模具中采取了以下设计措施来保证塑件的成型要求:一是通过主导柱、副导柱、模仁定位锥台等的设置,保证了塑件基本成型尺寸的成型精度;二是通过增加镶件排气措施、优化注射成型工艺参数等措施,有效降低和控制了塑件成型后的变形量,保证了塑件的成型形状精度,所增设的成型镶件有益于模腔排气,镶件间隙小于0.02 mm,镶件设计时须设计孔边扩距为1 mm,以降低镶件配模难度,避免镶件间隙飞边发生;三是为提高流道废料和塑件的冷却效率,脱料板中开设有2条?10 mm冷却水路,模腔成型件中开设有10条?10 mm冷却水路。模具中还设置了2个斜导柱滑块侧抽芯机构用于塑件两侧端面的脱模,塑件的最终脱模由多根顶针均衡顶出脱模。

个体化定制3D打印定位导板辅助显微手术切除幕上脑肿瘤

目的探讨基于CT与MRI多模态影像的3D打印技术辅助显微手术切除幕上脑肿瘤的可靠性与安全性。方法回顾性分析2021年6月至2022年6月手术切除的56例幕上脑肿瘤的临床资料。27例采用导航引导(导航组),29例采用3D打印导板定位辅助(3D打印组)。个体化3D打印导板定制流程:将术前CT、MRI等影像的DICOM格式的原始数据,发送至医学3D打印中心数据库,进行影像多模态融合并三维建模,清晰显示病灶与邻近重要血管神经的毗邻关系;根据模型进行手术路径合理规划,再利用手术路径与颅表特定部位关系,设计定位导板。结果两组病人均顺利完成手术,无手术死亡病例。3D打印组定位耗费时间较导航组明显缩短(P<0.05),但两组病灶精准度优良率、病灶全切除率、术后3月GOS评分均无统计学差异(P>0.05)。结论多模态影像融合3D打印技术可获得个体化的脑肿瘤三维实物模型和手术定位导板,能很好地指导手术切除幕上脑肿瘤,可替代部分神经导航的功能。

基于3D打印个性化截骨导板在内翻膝患者膝关节双间室置换术中的应用

目的 分析3D打印个性化截骨导板在内翻膝患者膝关节双间室置换术中的临床应用效果。方法 选取80例终末期内翻膝关节骨性关节炎且接受膝关节双间室置换术(TKA)的患者,随机分为2组,其中传统手术组40例(40膝),3D打印导板组40例(40膝)。分别记录2组手术时长、术中出血量、术后首次下床时间、术后股骨与胫骨机械轴夹角、VAS评分、膝关节HSS评分、WOMAC评分、膝关节活动度(ROM)等指标并统计分析。结果 所有患者均顺利实施手术并接受随访3~12个月。与传统手术组相比,3D打印导板组手术时长显著缩短(P <0.05),术中出血量、术后首次下床时间明显缩短(P <0.05),术后VAS评分、股骨与胫骨机械轴夹角低于传统手术组(P <0.01)。2组术后6个月KSS评分明显高于术前(P <0.01),术后6个月3D打印导板组KSS评分高于传统手术组(P <0.05),2组KSS评分差异无统计学意义(P> 0.05)。2组患者术后3个月、6个月WOMAC评分较术前均随着时间的推移而降低(P <0.05),术后3个月、6个月,3D打印导板组评分低于传统手术组(P <0.05)。除传统手术组出现积血感染1例,经再次清创后保存假体顺利出院外,所有手术患者未出现神经血管损伤、深静脉栓塞、假体松动、假体周围骨折等并发症。结论 基于3D打印截骨导板行膝关节置换术,较传统TKA手术具有手术操作时间短、失血量少、截骨精确快捷、术后恢复快、就诊满意度高等优点,临床疗效更具有优势。

数字化导板辅助植入种植体对老年前牙种植修复患者满意度及修复美学效果的影响

目的探究数字化导板辅助植入种植体对老年前牙种植修复患者满意度及修复美学效果的影响。方法回顾性选取2021年1月—2023年12月收治的行前牙种植修复的老年患者临床资料,依据修复方案不同进行分组,采用常规种植修复的42例(67颗种植体)为常规组,采用数字化导板辅助植入种植体修复的56例(84颗种植体)为数字化组。比较2组牙齿修复效果、种植准确度、咬合功能和种植体稳定性,记录修复后并发症与治疗费用,评价美学效果和患者满意度。结果术后第3个月和第6个月,数字化组美学、功能和生物学评分,种植体根部颊舌向与垂直向、颈部颊舌向与垂直向及根尖偏差距离均低于常规组(均P<0.05),咬合功能和种植体稳定性评分均高于常规组(均P<0.05);数字化组治疗费用高于常规组(P<0.05),手术时长少于常规组(P<0.05);数字化组术后3个月内并发症总发生率低于常规组(P<0.05);术后第3、第6个月,数字化组粉色美学指数(PES)、白色美学指数(WES)评分、对修复的满意度均高于常规组(均P<0.05)。结论数字化导板辅助植入种植体在老年患者前牙种植修复中效果良好,可减少并发症与治疗时长,保证精确度与稳定性,改善咬合功能和美观度,患者满意度提高。

大型双板导波天线对核电磁脉冲传输损耗和畸变特性

大型导波核电磁脉冲模拟器可为系统级装备试验提供自由空间辐照环境。针对此类模拟器常用的双板导波天线可能存在的传输损耗和波形畸变问题,以电磁仿真软件和算例对比分析研究了3种主要的影响因素,包括土壤的介电损耗及其抑制、前锥板向平行板转折的结构不连续、线栅阵列代替金属板的缝隙泄漏。研究结果表明:对上下极板等宽的情形,土壤损耗可使电压传输效率降低25%以上;适当展开下极板宽度可屏蔽土壤损耗;上极板转折处的结构不连续可导致平行段试验空间内电场呈现双峰交叠、幅度降低、波形畸变等特征;最大线间距0.3 m不会导致前沿显著变化。作为工程应用案例,设计了前锥长度60 m、顶高15 m、下极板拓宽3 m、由100根线栅阵列构成上极板的导波天线,试验空间超过20 m×20 m×10 m,实现了前沿2.5~3.0 ns双指数脉冲的无损耗、无畸变传输。

胫骨横向骨搬移微创导板技术联合桃红四物汤治疗糖尿病足溃疡的疗效分析

目的 观察胫骨横向骨搬移微创导板技术联合桃红四物汤治疗糖尿病足溃疡(diabetic foot ulcer,DFU)的疗效。方法 选取自2021年1月至2022年12月在湖南中医药大学第一附属医院四肢关节科拟进行胫骨横向骨搬移手术的50例DFU患者为研究对象,随机分为观察组与对照组,各25例。对照组采用胫骨横向骨搬移微创导板技术结合常规基础治疗;观察组在对照组基础上,术后第1天开始服用桃红四物汤,均连续治疗4周。比较治疗前和治疗后3个月两组患者的疼痛视觉模拟量表(visual analogue scale,VAS)评分、患肢皮肤温度、10 g尼龙丝检查评分、踝肱指数以及溃疡创面面积、愈合时间,评估临床疗效。结果 治疗3个月后,观察组临床有效率为92%,高于对照组的76%(P<0.05);观察组溃疡创面愈合时间较对照组明显缩短(P<0.05);两组患者的VAS评分、患肢皮肤温度、10 g尼龙丝检查评分、踝肱指数均较治疗前明显改善(P<0.05),且观察组上述各项指标较对照组改善更明显(P<0.05)。结论 胫骨横向骨搬移微创导板技术联合桃红四物汤治疗DFU的临床疗效显著,创伤小,创面愈合快,可明显缓解患肢疼痛,加速溃疡创面修复。

3D打印导板辅助穿刺引流术治疗脑出血临床观察

目的探讨3D打印导板辅助穿刺引流术治疗20 mL左右脑出血患者的临床疗效。方法将105例脑出血患者随机分为对照组和观察组,实施常规保守治疗的53例分为对照组,实施3D打印导板辅助穿刺引流术治疗的53例分为观察组。比较2组血肿清除率、神经功能[美国国立卫生研究院卒中量表(NIHSS)评分]、认知功能[简易智力状态检查量表(MMSE)评分]及肢体功能[Fugl-Meyer运动功能量表(FMA)评分],并记录2组治疗期间并发症情况。结果观察组治疗后1 d、3 d及10 d的血肿清除率分别为(78.45±5.06)%、(80.73±5.29)%及(82.68±5.17)%,高于对照组的(32.16±4.12)%、(36.47±4.38)%、(42.67±4.78)%(P<0.05),观察组住院时间短于对照组(P<0.05)。治疗后,观察组NIHSS评分为(13.17±1.82)分,显著低于对照组的(18.64±2.71)分(P<0.05),MMSE评分和FMA总评分显著高于对照组[(28.67±1.24)分比(26.25±2.62)分,(77.03±10.13)分比(65.50±8.89)分](P<0.05)。观察组总并发症发生率为5.76%,低于对照组的18.87%(P<0.05)。结论相对于保守治疗,3D打印导板辅助穿刺引流术治疗20 mL左右脑出血患者疗效确切,可显著提升患者血脂清除率,改善患者认知功能和肢体功能,且能降低脑出血总并发症发生率。