Experimental investigation on the invert stability of operating railway tunnels with different drainage systems using 3D printing technology

In recent years, the invert anomalies of operating railway tunnels in water-rich areas occur frequently,which greatly affect the transportation capacity of the railway lines. Tunnel drainage system is a crucial factor to ensure the invert stability by regulating the external water pressure(EWP). By means of a threedimensional(3D) printing model, this paper experimentally investigates the deformation behavior of the invert for the tunnels with the traditional drainage system(TDS) widely used in China and its optimized drainage system(ODS) with bottom drainage function. Six test groups with a total of 110 test conditions were designed to consider the design factors and environmental factors in engineering practice,including layout of the drainage system, blockage of the drainage system and groundwater level fluctuation. It was found that there are significant differences in the water discharge, EWP and invert stability for the tunnels with the two drainage systems. Even with a dense arrangement of the external blind tubes, TDS was still difficult to eliminate the excessive EWP below the invert, which is the main cause for the invert instability. Blockage of drainage system further increased the invert uplift and aggravated the track irregularity, especially when the blockage degree is more than 50%. However, ODS can prevent these invert anomalies by reasonably controlling the EWP at tunnel bottom. Even when the groundwater level reached 60 m and the blind tubes were fully blocked, the invert stability can still be maintained and the railway track experienced a settlement of only 1.8 mm. Meanwhile, the on-site monitoring under several rainstorms further showed that the average EWP of the invert was controlled within 84 k Pa, while the maximum settlement of the track slab was only 0.92 mm, which also was in good agreement with the results of model test.

Three-dimensional printing technology for patient-matched instrument in treatment of cubitus varus deformity:A case report

BACKGROUND Recently,medical three-dimensional printing technology(3DPT)has demonstrated potential benefits for the treatment of cubitus varus deformity(CVD)by improving accuracy of the osteotomy through the use of an osteotomy guide,with or without a patient-mated plate.Here,we present an interesting CVD case,involving a patient who was treated with corrective biplanar chevron osteotomy using an innovative customized osteotomy guide and a newly designed patient-matched monoblock crosslink plate created with 3DPT.CASE SUMMARY A 32-year-old female presented with a significant CVD from childhood injury.A computer simulation was processed using images from computerized tomography scans of both upper extremities.The biplanar chevron osteotomy was designed to create identical anatomy between the mirror image of the contralateral distal humerus and the osteotomized distal humerus.Next,the customized osteotomy guide and patient-matched monoblock crosslink plate were designed and printed.A simulation osteotomy was created for the real-sized bone model,and the operation was performed using the posterior paratricipital approach with k-wire positioning from the customized osteotomy guide as a predrilled hole for screw fixation to achieve immediate control of the reduction after osteotomy.Our method allowed for successful treatment of the CVD case,significantly improving the patient’s radiographic and clinical outcomes,with satisfactory result.CONCLUSION 3DPT-created patient-matched osteotomy guide and instrumentation provides accurate control during CVD correction.

Interventional Therapy for Cerebral Aneurysms Under the Guidance of 3D Printing Technology

Objective:To explore the clinical method and effect of 3D printing in the treatment of cerebral aneurysms.Methods:The authors research work on the hospital,work time in February 2019-February 2020,this study selected patients of cerebral aneurysms,this period are selected for treatment of 100 cases of patients,randomly divided into two groups,a group to give simple intervention,named as the control group,another group for the interventional therapy under the guidance of 3 D printing,named as experimental group,analyze the effect of two groups of patients with clinical intervention.Results:The length of hospital stay in the experimental group was shorter than that in the control group.Meanwhile,the incidence of complications and adverse reactions in the experimental group and the control group were 6.00%and 18.00%,the experimental group was better(P<0.05).Conclusion:3D printing technology can be applied in the treatment of patients with cerebral aneurysms to provide guidance for interventional surgical treatment.It has significant effect,can reduce the incidence complications in patients,has significant clinical effect,and can be popularized.

It's Closed In Triumph,'97 International Screen Special Printing Technology Exhibition

’97 Wuhan International Screen Special Printing Technology Exhibition was held from May 21—24, 1997 in Wuhan city,the capital of Hubei Province. 120 famous exhibitors from China, USA, Canada, Holland, Japan, Korea, and Hong Kong, Taiwan districts attended the Exhibition. The booth area was more than 5000 m^2.

An analysis of the development trends of China's printing and printing machinery manufacture technology——Presentation in the International Forum for the Development of Printing Technology

2006 is the commencing year of the Eleventh Five-Year Plan for National Economic and Social Development, and also the fifth anniversary of China joining the World Trade Organization. After the development of the transition period in these years, China’s national economy has successfully inte grated into the global system. National economy remains de- veloping at a high speed. The total amount of import and export reached more than 1.4 trillion USD,

The First International Digital Printing and Image Technology Exhibition & The Sixth International Exhibition of Quick Printing Equipment & Technology

Time: Sept.4-6, 2008Venue: Shenzhen Convention & Exhibition CenterSponsor: Printing and Printing Equipment Industries Association of China (PEIAC)Organizers: The Exhibition Department of

Advancing Wound Filling Extraction on 3D Faces:An Auto-Segmentation and Wound Face Regeneration Approach

Facial wound segmentation plays a crucial role in preoperative planning and optimizing patient outcomes in various medical applications.In this paper,we propose an efficient approach for automating 3D facial wound segmentation using a two-stream graph convolutional network.Our method leverages the Cir3D-FaIR dataset and addresses the challenge of data imbalance through extensive experimentation with different loss functions.To achieve accurate segmentation,we conducted thorough experiments and selected a high-performing model from the trainedmodels.The selectedmodel demonstrates exceptional segmentation performance for complex 3D facial wounds.Furthermore,based on the segmentation model,we propose an improved approach for extracting 3D facial wound fillers and compare it to the results of the previous study.Our method achieved a remarkable accuracy of 0.9999993% on the test suite,surpassing the performance of the previous method.From this result,we use 3D printing technology to illustrate the shape of the wound filling.The outcomes of this study have significant implications for physicians involved in preoperative planning and intervention design.By automating facial wound segmentation and improving the accuracy ofwound-filling extraction,our approach can assist in carefully assessing and optimizing interventions,leading to enhanced patient outcomes.Additionally,it contributes to advancing facial reconstruction techniques by utilizing machine learning and 3D bioprinting for printing skin tissue implants.Our source code is available at https://github.com/SIMOGroup/WoundFilling3D.

A reusable planar triggered spark-gap switch batched-fabricated with PCB technology for medium- and low-voltage pulse power systems

Triggered spark-gap switch is a popular discharge switch for pulse power systems.Previous studies have focused on planarizing this switch using thin film techniques in order to meet the requirements of compact size in the systems.Such switches are one-shot due to electrodes being too thin to sufficiently resist spark-erosion.Additionally,these switches did not employ any structures in securing internal gas composition,resulting in inconsistent performance under harsh atmospheres.In this work,a novel planar triggered spark-gap switch(PTS)with a hermetically sealed cavity was batched-prepared with printed circuit board(PCB)technology,to achieve reusability with low cost.The proposed PTS was inspected by micro-computed tomography to ensure PCB techniques meet the requirements of machining precision.The results from electrical experiments demonstrated that PCB PTS were consistent and reusable with lifespan over 20 times.The calculated switch voltage and circuit current were consistent with those derived from real-world measurements.Finally,PCB PTS was used to introduce hexanitrostilbene(HNS)pellets in a pulse power system to verify its performance.

Three-dimensional printed talar prosthesis with biological function for giant cell tumor of the talus:A case report and review of the literature

BACKGROUND Giant cell tumors(GCT)are most commonly seen in the distal femur.These tumors are uncommon in the small bones of the hand and feet,and a very few cases have been reported.A giant cell tumor of the talus is rarely seen clinically and could be a challenge to physicians.CASE SUMMARY We report a rare case of GCT of the talus in one patient who underwent a new reconstructive surgery technique using a three-dimensional(3D)printing talar prosthesis.The prosthesis shape was designed by tomographic image processing and segmentation using technology to match the intact side by mirror symmetry with 3D post-processing technologies.The patient recovered nearly full range of motion of the ankle after 6 mo.The visual analogue scale and American Orthopaedic Foot and Ankle Society scores were 1 and 89 points,respectively.CONCLUSION We demonstrated that 3D printing of a talar prosthesis is a beneficial option for GCT of the talus.

Mechanical Experiment for 3D Printing of Titanium Bone Bionic Dental Implants

[Objectives] To explore the flexural strength of 3D printed titanium bone bionic dental implants and provide a scientific basis for the clinical application of 3D printed porous bionic bone dental implants. [Methods] The cone-beam CT( CBCT) image information of 20 premolars extracted by orthodontic requirement was collected,and a new porous bone bionic dental implant was produced using modeling software and 3D printer. The premolars were divided into two groups( A and B). The universal testing machine was used to test the flexural strength of the two groups and the difference in flexural strength between the two groups was compared through statistics. [Results]Twenty 3D printed porous titanium bone bionic implants were accurately produced; the morphology of group A and group B were extremely similar to each other; the average flexural strength of group A was 2 767. 92 N,while the average flexural strength of group B was 778. 77 N,showing that the average flexural strength of group A was significantly higher than that of group B,and the difference was statistically significant( P < 0. 05).[Conclusions]The personalized porous structure root implants produced by 3D printing technology are very similar to the target tooth morphology,and show high accuracy and small error of production. Besides,the flexural strength of 3D printed personalized porous structure root implants can fully meet the requirements of the maximum occlusal force for dental implant restoration. It is expected to provide a scientific basis for clinical application of 3 D printed porous bionic bone tooth implants.

Analysis on the Development of Cigarette Packaging in the Era of Intelligence

China is one of the biggest countries in cigarette production and sales,therefore it is important to improve the quality and efficiency of cigarette production.As cigarette packaging is an important part in cigarette production,therefore,it is important to strengthen research on improving the quality of cigarette packaging.This article summarizes the development process of cigarette packaging in China,introduces the development of printing technology in the era of intelligence,summarizes the application of printing technology in cigarette packaging,analyzes and explores the development trend of cigarette packaging in the era of intelligence,with the hope to provide reference for practitioners.

Opportunities and challenges of three-dimensional printing technology in pharmaceutical formulation development

Three-dimensional printing is a technology that prints the products layer-by-layer,in which materials are deposited according to the digital model designed by computer aided design(CAD)software.This technology has competitive advantages regarding product design complexity,product personalization,and on-demand manufacturing.The emergence of 3 D technology provides innovative strategies and new ways to develop novel drug delivery systems.This review summarizes the application of 3 D printing technologies in the pharmaceutical field,with an emphasis on the advantages of 3 D printing technologies for achieving rapid drug delivery,personalized drug delivery,compound drug delivery and customized drug delivery.In addition,this article illustrates the limitations and challenges of 3 D printing technologies in the field of pharmaceutical formulation development.

Design and fabrication of r-hirudin loaded dissolving microneedle patch for minimally invasive and long-term treatment of thromboembolic disease

Cardiovascular disease is the leading cause of global mortality,with anticoagulant therapy being the main prevention and treatment strategy.Recombinant hirudin(r-hirudin)is a direct thrombin inhibitor that can potentially prevent thrombosis via subcutaneous(SC)and intravenous(IV)administration,but there is a risk of haemorrhage via SC and IV.Thus,microneedle(MN)provides painless and sanitary alternatives to syringes and oral administration.However,the current technological process for the micro mould is complicated and expensive.The micro mould obtained via three-dimensional(3D)printing is expected to save time and cost,as well as provide a diverse range of MNs.Therefore,we explored a method for MNs array model production based on 3D printing and translate it to micro mould that can be used for fabrication of dissolving MNs patch.The results show that r-hirudin-loaded and hyaluronic acid(HA)-based MNs can achieve transdermal drug delivery and exhibit significant potential in the prevention of thromboembolic disease without bleeding in animal models.These results indicate that based on 3D printing technology,MNs combined with r-hirudin are expected to achieve diverse customizableMNs and thus realize personalized transdermal anticoagulant delivery for minimally invasive and long-term treatment of thrombotic disease.

Research progress of localization technique assisted neuroendoscopy for cerebral hemorrhage

Neurosurgeons who perform intracere-bral hemorrhage(ICH)evacuation procedures have lim-ited options for monitoring hematoma evacuation and intraoperatively assessing residual-hematoma burden.In recent years,neuroendoscope-assisted,minimally inva-sive surgery for spontaneous ICH is simple and effective and becoming increasingly common.Many methods are applied in neuronavigation-assisted surgery for ICH evac-uation,such as neuroendoscopy,three-dimensional(3D)reconstruction,intraoperative ultrasound,and stereotac-tic craniotomy.Compared with a traditional craniotomy operation,hematoma removal(using methods of accurate localization)can reduce iatrogenic damage,protect white matter,and shorten patients’recovery time.This paper mainly outlines the treatment of basal ganglia-cerebral hemorrhage with neuroendoscopy assistance using local-ization techniques.

Strain Sensor Based on Embedded Fiber Bragg Grating in Thermoplastic Polyurethane Using the 3D Printing Technology for Improved Sensitivity

A new and easy-to-fabricate strain sensor has been developed,based on fiber Bragg grating(FBG)technology embedded into a thermoplastic polyurethane filament using a 3-dimensional(3D)printer.Taking advantage of the flexibility and elastic properties of the thermoplastic polyurethane material,the embedding of the FBG provides durable protection with enhanced flexibility and sensitivity,as compared to the use of a bare FBG.Results of an evaluation of its performance have shown that the FBG sensors embedded in this way can be applied effectively in the measurement of strain,with an average wavelength responsivity of 0.0135 nm/cm of displacement for tensile strain and -0.0142 nm/cm for compressive strain,both showing a linearity value of up to 99%.Furthermore,such an embedded FBG-based strain sensor has a sensitivity of~1.74 times greater than that of a bare FBG used for strain measurement and is well protected and suitable for in-the-field use.It is also observed that the thermoplastic polyurethane based(TPU-based)FBG strain sensor carries a sensitivity value of~2.05 times higher than that of the polylactic acid based(PLA-based)FBG strain sensor proving that TPU material can be made as the material of choice as a“sensing”pad for the FBG.

3D printing method for bone tissue engineering scaffold

3D printing technology is an emerging technology.It constructs solid bodies by stacking materials layer by layer,and can quickly and accurately prepare bone tissue engineering scaffolds with specific shapes and structures to meet the needs of different patients.The field of life sciences has received a great deal of attention.However,different 3D printing technologies and materials have their advantages and disadvantages,and there are limitations in clinical application.In this paper,the technology,materials and clinical applications of 3D printed bone tissue engineering scaffolds are reviewed,and the future development trends and challenges in this field are prospected.

Broadband millimeter-wave metasurface antenna array withprinted ridge gap waveguide for high front-to-back ratio

A novel broadband metasurface (MTS) antenna array with high front-to-back ratio (FBR) is proposed for 28 GHz millimeter-wave applications. With slot pairs loaded on patch cells, an aperturecoupled slotted-mushroom MTS antenna is designed to obtain broadband radiation characteristicswith a compact size. To suppress the backward radiation of this antenna, the printed ridge gapwaveguide (PRGW) technology with a perfect magnetic conductor (PMC) shielding made ofmushroom unit-cells underneath the microstrip feeding line is applied. On this basis, a 4×4 MTSantenna array with the PRGW feed network is developed. Simulated results show that the FBR canbe highly improved by over 16 dB within the entire bandwidth. To validate the design, a prototypeof the proposed antenna is fabricated. Measured results show that an FBR greater than 28 dB canbe obtained over a 24% impedance bandwidth (from 24.9 GHz to 31.7 GHz) with the reflectioncoefficient less than 10 dB. The measured antenna gain ranges from 17 dBi to 19.2 dBi and thecorresponding measured aperture efficiencies are 35% and 45.6%. The measured results alsosuggest that the proposed MTS antenna possesses -35 dB cross-polarization level and stable radiation patterns. In addition, the proposed antenna remains a very low profile of 1.7 mm (0.17λ_(0) at28 GHz). All the achieved features indicate that the proposed MTS antenna is an importantcandidate for B5G and 6G wireless communication.

Large-area Flexible Organic Solar Cells: Printing Technologies and Modular Design

Flexibility is the most prominent advantage of organic solar cells(OSCs) compared with traditional photovoltaic devices, showing an irreplaceable commercial potential. Currently, the maximum power conversion efficiencies(PCEs) of single-junction OSCs have been over 19% and 16% upon rigid and flexible substrates, respectively, which meet the criteria for commercial application. Extensive research efforts are under way, such as device configuration design, interface/photosensitive layer synthesis, transparent electrode modification and printing technology innovation, however, the reasonable selection of printing technologies, the huge performance loss of large-area printing process and the structural design of flexible modules are still the bottlenecks, limiting the commercialization of OSCs. This review focuses on the technical challenges and rational modular configuration design for printing preparation of flexible high-efficiency large-area organic devices, from the aspects of the functional layer material selection, printing process research status and large-scale efficiency losses. These will promote the integrated applications of printable organic semiconductor materials for next-generation clean energy and appeal extensive attentions in wearable electronics, building-integrated photovoltaics and Internet of Things, etc.

Biomedical applications of the powder-based 3D printed titanium alloys:A review

3D printing technology is a new type of precision forming technology and the core technology of the third industrial revolution.The powder-based 3D printing technology of titanium and its alloys have received great attention in biomedical applications since its advantages of custom manufacturing,costsaving,time-saving,and resource-saving potential.In particular,the personalized customization of 3D printing can meet specific needs and achieve precise control of micro-organization and structural design.The purpose of this review is to present the most advanced multi-material 3D printing methods for titanium-based biomaterials.We first reviewed the bone tissue engineering,the application of titanium alloy as bone substitutes and the development of manufacturing technology,which emphasized the advantages of 3D printing technology over traditional manufacturing methods.What is more,the optimization design of the hierarchical structure was analyzed to achieve the best mechanical properties,and the biocompatibility and osseointegration ability of the porous titanium alloy after implantation in living bodies was analyzed.Finally,we emphasized the development of digital tools such as artificial intelligence,which provides new ideas for the rational selection of processing parameters.The 3D printing titanium-based alloys will meet the huge market demand in the biomedical field,but there are still many challenges,such as the trade-off between high strength and low modulus,optimization of process parameters and structural design.We believe that the combination of mechanical models,machine learning,and metallurgical knowledge may shape the future of metal printing.

Liquid metal E-tattoo

The past twenty years have witnessed a rapid advancement in medical devices and healthcare techniques.Motivated by the growing demand for personalized,preventive,predictive and participatory medicine,the on-skin portable healthcare system with fascinating merits has attracted great interest.Especially,the electronic tattoo(E-tattoo)that can form intimate contact and deform with the skin movement is regarded to play an important role in further healthcare monitoring and disease treatment.Endowed with the combination of fluidity and metallic properties,liquid metals(LMs)have become an emerging class of functional materials and are regarded as the ideal candidate for soft electronics.Here,we highlighted the key advantages of LM in E-tattoo,classified the LM based conductive inks,and summarized the important pattern technologies in fabrication of LM E-tattoo.The typical applications of healthcare detection and therapy were also discussed.Finally,outlooks were provided for future E-tattoo development.