调而不适:政策学习的目标替代机制研究——基于科技创新券政策的案例研究

政策调适通过知识整合和政策学习等机制,实现政策对象清晰化、政策工具精准化和政策目标明确化,是对政府治理复杂政策及其执行问题的适应机制。但是,促进民营经济发展的科技创新券政策调适过程,却呈现出目标替代的非预期结果,从而导致调而不适的政策现象。研究区别于现有研究将政策目标替代归因于科层组织中层级关系带来的利益冲突,立足于政策过程理论本身,基于政策学习理论,引入政策知识生产概念,构建政企双向学习合作知识生产路径,分析科技创新券政策过程中目标替代结果的形成机制。研究采用案例分析方法,选择科技创新券政策这一政企互动的典型案例作为研究对象。研究发现,技术创新活动的特性,决定科技创新券政策属于高知识密度和高风险密度耦合的政策类型,政策学习指向新的政策知识生产,形成政企双向学习合作知识生产路径,政策知识生产不足,导致目标替代的消极结果。研究提出政策学习过程中的政企双向学习和知识生产,通过引入企业这一主体的政策学习过程,为政策目标替代的形成机制提供新的解释视角。此外,研究重点关注了高知识密度和高风险密度耦合的技术创新补贴政策,以期为促进民营经济高质量发展的系列政策实践提供参考。

A method to predict rockburst using temporal trend test and its application

Rockbursts have become a significant hazard in underground mining,underscoring the need for a robust early warning model to ensure safety management.This study presents a novel approach for rockburst prediction,integrating the Mann-Kendall trend test(MKT)and multi-indices fusion to enable real-time and quantitative assessment of rockburst hazards.The methodology employed in this study involves the development of a comprehensive precursory index library for rockbursts.The MKT is then applied to analyze the real-time trend of each index,with adherence to rockburst characterization laws serving as the warning criterion.By employing a confusion matrix,the warning effectiveness of each index is assessed,enabling index preference determination.Ultimately,the integrated rockburst hazard index Q is derived through data fusion.The results demonstrate that the proposed model achieves a warning effectiveness of 0.563 for Q,surpassing the performance of any individual index.Moreover,the model’s adaptability and scalability are enhanced through periodic updates driven by actual field monitoring data,making it suitable for complex underground working environments.By providing an efficient and accurate basis for decision-making,the proposed model holds great potential for the prevention and control of rockbursts.It offers a valuable tool for enhancing safety measures in underground mining operations.

Non-destructive buffer enabling near-infrared-transparent inverted inorganic perovskite solar cells toward 1400 h light-soaking stable perovskite/Cu(In,Ga)Se_(2) tandem solar cells

Near-infrared(NIR)transparent inverted all-inorganic perovskite solar cells(PSCs)are excellent top cell candidates in tandem applications.An essential challenge is the replacement of metal contacts with transparent conductive oxide(TCO)electrodes,which requires the introduction of a buffer layer to prevent sputtering damage.In this study,we show that the conventional buffers(i.e.,small organic molecules and atomic layer deposited metal oxides)used for organic-inorganic hybrid perovskites are not applicable to all-inorganic perovskites,due to non-uniform coverage of the vulnerable layers underneath,deterioration upon ion bombardment and moisture induced perovskite phase transition,A thin film of metal oxide nanoparticles by the spin-coating method serves as a non-destructive buffer layer for inorganic PSCs.All-inorganic inverted near-infrared-transparent PSCs deliver a PCE of 17.46%and an average transmittance of 73.7%between 780 and 1200 nm.In combination with an 18.56%Cu(In,Ga)Se_(2) bottom cell,we further demonstrate the first all-inorganic perovskite/CIGS 4-T tandem solar cell with a PCE of 24.75%,which exhibits excellent illumination stability by maintaining 86.7%of its initial efficiency after 1400 h.The non-destructive buffer lays the foundation for efficient and stable NIR-transparent inverted inorganic perovskite solar cells and perovskite-based tandems.

The impact of short-term changes in sleeping and eating patterns on glucometabolic health and gut microbiota in healthy young adults: a proof-of-concept controlled feeding study

Epidemiological studies showed that night workers are at higher risk of developing chronic metabolic diseases.However,no study has investigated the changes in circadian rhythms caused by a combined effect of sleep and diet in a real-life setting on cardiometabolic health,gut microbiota,and psychological status in healthy people.A 4-week step-wise misaligned-realigned controlled-feeding trial with a 2×2 factorial design(sleep and diet)was conducted on healthy young adults.At first,subjects experienced a one-week circadian rhythm misalignment with a high-fat fast-food diet,extended eating window,and delayed sleep schedules,then gradually transited to a complete circadian rhythm realignment with a high-fiber balanced diet,8-h timerestricted eating,and normal sleep schedules.Circadian rhythm misalignment led to significantly higher levels of fasting glucose and homeostatic model assessment for insulin resistance(HOMA-IR)of subjects compared to baseline and failed to recover to the baseline level in circadian rhythm realignments.Notably,the incremental area under the curve(iAUC)of postprandial glucose decreased with circadian rhythm adjustments as compared to that in circadian rhythm misalignment,suggesting circadian rhythm realignment by sleep or/and diet could partly restore glucose metabolism impaired by a short-term circadian rhythm misalignment.However,circadian rhythm changes did not result in overall perturbations of gut microbiota diversities.

Antibacterial and angiogenic dual-functional fibrous membrane dressing for infected wound healing

Background:Skin,being a vital organ that regulates physiological responses in the human body,is prone to injury from external environmental factors.Healing full-thickness skin defects becomes especially challenging when infections and vascular injuries are involved.Traditional wound dressings with single functions,such as antibacterial or angiogenic properties,fall short in achieving rapid wound healing.To address this,there is a need to develop wound dressing materials that possess both effective antibacterial and angiogenic properties.Methods:In this study,we utilized electrospinning technology to fabricate hyaluronic acid-cellulose acetate fibrous membrane dressings,incorporating poly(ionic liquid)as an antibacterial polymer and deferoxamine as an angiogenic agent.Results:The resulting fibrous membrane dressing contained poly(ionic liquid)and deferoxamin showcased a microporous structure,drug-releasing capabilities,and excellent air permeability.It not only demonstrated highly effective antibacterial properties but also exhibited remarkable angiogenesis,thereby promoting the healing of full-thickness skin defect wounds in both in vitro and in vivo assays.Conclusion:These findings highlight the immense potential of this wound dressing material for future clinical applications.

Continuous positive airway pressure for treating hypoxemia due to pulmonary vein injury:A case report

BACKGROUND Vascular injury during thoracoscopic surgery for esophageal cancer is a rare but life-threatening complication that can lead to severe hypotension and hypoxemia.Anesthesiologists need to provide rapid and effective treatment to save patients'lives.CASE SUMMARY A 54-year-old male patient was scheduled to undergo a thoracoscopic-assisted radical resection of esophageal cancer through the upper abdomen and right chest.While dissociating the esophagus from the carina through the right chest,unexpected profuse bleeding occurred from a suspected pulmonary vascular hemorrhage.While the surgeon attempted to achieve hemostasis,the patient developed severe hypoxemia.The anesthesiologist implemented continuous positive airway pressure(CPAP)using a bronchial blocker(BB),which effectively improved the patient’s oxygenation and the operation was completed success-fully.CONCLUSION CPAP using a BB can resolve severe hypoxemia caused by accidental injury of the left inferior pulmonary vein during surgery.

A two-step method to detect broadcast ephemeris unavailable periods caused by BeiDou satellite orbital maneuvers

The space constellation of the BeiDou navigation satellite system(BDS) is a hybrid constellation containing medium earth orbit(MEO) satellites, geostationary earth orbit(GEO) satellites, and inclined geosynchronous orbit(IGSO) satellites. Due to the geosynchronous characteristics of GEO and IGSO, GEO satellites and IGSO satellites often need to perform orbital maneuvers, which can affect the signal-inspace(SIS) availability performance of BeiDou satellites. A two-step detection method for BeiDou satellite orbital maneuvers has been proposed in this paper. The first step is to identify orbital maneuvers based on time series analysis of broadcast ephemeris, and the second step is to verify orbital maneuvers based on bidirectional orbit prediction. The two-step detection method was used to detect the orbital maneuvers of BeiDou satellites in 2019. Through the double guarantees of identification and verification,the detection accuracy of BeiDou satellite orbital maneuvers has been effectively improved. And the orbital maneuver detection results are continued to be used to assess the SIS availability of BeiDou satellites. The results show that the availability loss of GEO satellite orbital maneuvers is about 0.45%-1.07%, and the availability loss of IGSO satellite orbital maneuvers is about 0.12%-0.19%.

RASAL2 acts as a tumor suppressor in cervical cancer cells

This study was designed to investigate the roles of RASAL2 in cervical cancer(CC).Methods:Fifty-four CC tissues and 33 adjacent tissues were obtained from CC patients admitted to our hospital between March 2012 and June 2014.Real-time polymerase chain reaction and western blotting were performed to analyze the expression of RASAL2 mRNA and protein in these tissues,CC cell lines,and normal cervical cells.Over-expression and silencing of RASAL2 were induced after transfection,and the migration,invasion,and proliferation of the CC cell lines were examined.Results:RASAL2 mRNA and protein expressions were significantly down-regulated in CC tissues and cell lines than in adjacent tissues and normal cervical cells,respectively.While low RASAL2 expression correlated with advanced stage and metastasis of CC,its over-expression significantly inhibited proliferation and metastasis of CC cells and induced apoptosis.Under in vitro conditions,silencing of RASAL2 expression could significantly increase the proliferation,invasion,and migration of CC cells.Conclusion:RASAL2 functioned as a tumor suppressor in CC,and was down-regulated in CC tissue samples and cell lines.

Fish Feeding Behavior Recognition Using Adaptive DMCA-UMT Algorithm

Realtime analyzing the feeding behavior of fish is the premise and key to accurate guidance on feeding.The identification of fish behavior using a single information is susceptible to various factors.To overcome the problems,this paper proposes an adaptive deep modular co-attention unified multi-modal transformers(DMCA-UMT).By fusing the video,audio and water quality parameters,the whole process of fish feeding behavior could be identified.Firstly,for the input video,audio and water quality parameter information,features are extracted to obtain feature vectors of different modalities.Secondly,deep modular co-attention(DMCA)is introduced on the basis of the original cross-modal encoder,and the adaptive learnable weights are added.The feature vector of video and audio joint representation is obtained by automatic learning based on fusion contribution.Finally,the information of visual-audio modality fusion and text features are used to generate clip-level moment queries.The query decoder decodes the input features and uses the prediction head to obtain the final joint moment retrieval,which is the start-end time of feeding the fish.The results show that the mAP Avg of the proposed algorithm reaches 75.3%,which is37.8%higher than that of unified multi-modal transformers(UMT)algorithm.

Construction of gene/protein interaction networks and enrichment pathway analysis for paroxysmal nocturnal hemoglobinuria and aplastic anemia

Background:To develop a protein-protein interaction network of Paroxysmal nocturnal hemoglobinuria(PNH)and Aplastic anemia(AA)based on genetic genes and to predict pathways underlying the molecular complexes in the network.Methods:In this research,the PNH and AA-related genes were screened through Online Mendelian Inheritance in Man(OMIM).The plugins and Cytoscape were used to search literature and build a protein-protein interaction network.Results:The protein-protein interaction network contains two molecular complexes that are five higher than the correlation integral values.The target genes of this study were obtained:CD59,STAT3,TERC,TNF,AKT1,C5AR1,EPO,IL6,IL10 and so on.We also found that many factors regulate biological behaviors:neutrophils,macrophages,vascular endothelial growth factor,immunoglobulin,interleukin,cytokine receptor,interleukin-6 receptor,tumor necrosis factor,and so on.This research provides a bioinformatics foundation for further explaining the mechanism of common development of both.Conclusion:This indicates that the PNH and AA is a complex process regulated by many cellular pathways and multiple genes.

某高校医学硕士研究生心理健康问题现状及对策研究

目的:分析“医教协同”背景下医学硕士研究生心理健康问题现状,探讨开展医学生心理健康教育的对策。方法:选取某高校医学硕士研究生作为研究对象,进行问卷调查及统计分析,对影响因素进行调查分析,并制定相应的对策。结果:(1)医学硕士研究生存在心理健康问题最高和最低的因子分别是强迫症状和恐怖,检出率分别为9.06%、1.29%。(2)不同年级的医学硕士研究生均存在抑郁、焦虑等心理健康问题,其中2014级焦虑发生率最高(1.75%),2013级抑郁发生率最高(17.95%);心理健康问题最为严重的是2013级,检出率为10.20%。(3)医学硕士研究生SCL-90各个因子评分均低于常模组,差异具有统计学意义(P<0.001)。结论:医学硕士研究生面临着不同心理健康问题,只有社会、学校、导师等各方面给予支持和关爱,才能为其提供良好的成长环境。

基于近红外机器视觉的鱼类摄食强度评估方法研究

在水产养殖中,鱼类的摄食强度可以反映其食欲,准确客观地评估鱼类的摄食强度对指导投喂和生产实践具有重要意义。针对当前鱼类摄食强度评估过程中存在的人工观测效率低、客观性不强的问题,本研究以实现鱼类食欲的自动客观分析为目的,提出了一种基于近红外机器视觉的游泳型鱼类摄食强度的评估方法。首先,利用近红外工业相机搭建了近红外图像采集系统,采集了鱼类摄食过程中的图像。经过一系列图像处理步骤后,利用灰度共生矩阵提取摄食图像的纹理特征变量信息,包括对比度、能量、相关性、逆差距和熵等。之后,将这5个特征变量作为输入向量构建了模型的数据集,并训练了支持向量机分类器。为了提高模型分类的准确率,利用网格搜索法选取支持向量机分类器的最优惩罚系数c和核函数参数g。最后利用训练好的模型将鱼类的摄食强度分为弱、一般、中和强4类,最终实现了鱼类摄食强度的评估。试验结果表明,图像纹理可以较好地描述鱼类摄食过程中的行为变化,正确识别4类摄食强度的准确率达到87.78%,且不需要考虑水花等对成像质量的影响,具有较强的适应性。本方法可用于鱼类食欲的自动客观评估,为后续投喂决策提供理论依据和方法支持。

VR技术在医学计量与质量控制教育培训中的研究

目的通过对VR(虚拟现实)技术的研究,探讨了将VR技术运用于"VR/AR+培训"模式的重要意义。方法通过总结工作实践经验,针对医疗设备质量控制管理及其培训教学运用情况特点进行分类,分析存在的问题并给出建议。结果医院医疗设备质量管理的发展必须顺应时代发展的大环境,打破传统设备管理的工作模式,实现了先进的虚实结合,促进了教育培训多样化形式的发展;增加操作者身临其境的感觉,帮助他们快速掌握要领,提高了获得感和教学效果。结论 AR与VR技术在医学计量和质量检测培训中必将引领时代潮流。

高效液相色谱法检测发酵液中四氢嘧啶及羟基四氢嘧啶

为实现发酵液样品中四氢嘧啶和羟基四氢嘧啶的分离检测,使用高效液相色谱(HPLC)技术建立一种测定中度嗜盐菌发酵液中四氢嘧啶及羟基四氢嘧啶含量的方法。使用乙醇抽提法提取样品,采用Vertex^(TM) NH_(2)(4.6×250 mm,5μm)液相色谱柱对中度嗜盐菌发酵液中四氢嘧啶及四氢嘧啶进行了分析,选用紫外(UV)检测器,对比不同检测条件。通过色谱条件优化,选定了70%乙腈作为流动相,柱温30℃,检测波长210 nm,流速0.8 mL/min。发酵液样品中四氢嘧啶和羟基四氢嘧啶在各自范围内线性关系良好,两种样品的平均回收率在99.2%~102%,精密度偏差在1%~2%范围内,检出限为1.5μg/mL,定量限为5μg/mL,分离度为1.70。该方法检测范围大,具有较好的重复性、分离度及稳定性,适用于发酵液中四氢嘧啶及羟基四氢嘧啶的分离检测。

High levels of serum interleukin-6 increase mortality of hepatitis B virus-associated acute-on-chronic liver failure

BACKGROUND Patients with hepatitis B virus-associated acute-on-chronic liver failure(HBVACLF)present a complex and poor prognosis.Systemic inflammation plays an important role in its pathogenesis,and interleukin-6(IL-6)as a pro-inflammatory cytokine is related with severe liver impairment and also plays a role in promoting liver regeneration.Whether serum IL-6 influences HBV-ACLF prognosis has not been studied.AIM To determine the impact of serum IL-6 on outcome of patients with HBV-ACLF.METHODS We performed a retrospective study of 412 HBV-ACLF patients.The findings were analyzed with regard to mortality and the serum IL-6 level at baseline,as well as dynamic changes of serum IL-6 within 4 wk.RESULTS The serum IL-6 level was associated with mortality.Within 4 wk,deceased patients had significantly higher levels of IL-6 at baseline than surviving patients[17.9(7.3-57.6)vs 10.4(4.7-22.3),P=0.011].Patients with high IL-6 levels(>11.8 pg/mL)had a higher mortality within 4 wk than those with low IL-6 levels(≤11.8 pg/mL)(24.2%vs 13.2%,P=0.004).The odds ratios calculated using univariate and multivariate logistic regression were 2.10(95%confidence interval[CI]:1.26-3.51,P=0.005)and 2.11(95%CI:1.15-3.90,P=0.017),respectively.The mortality between weeks 5 and 8 in patients with high IL-6 levels at 4 wk was 15.0%,which was significantly higher than the 6.6%mortality rate in patients with low IL-6 levels at 4 wk(hazard ratio=2.39,95%CI:1.05-5.41,P=0.037).The mortality was 5.0%in patients with high IL-6 levels at baseline and low IL-6 levels at 4 wk,7.5%in patients with low IL-6 levels both at baseline and at 4 wk,11.5%in patients with low IL-6 levels at baseline and high IL-6 levels at 4 wk,and 16.7%in patients with high IL-6 levels both at baseline and at 4 wk.The increasing trend of the mortality rate with the dynamic changes of IL-6 was significant(P for trend=0.023).CONCLUSION A high level of serum IL-6 is an independent risk factor for mortality in patients with HBV-ACLF.Furthermore,a sustained high level or dynamic elevated level of serum IL-6 indicates a higher mortality.

Mechanism and monitoring and early warning technology for rockburst in coal mines

On the basis of the massive amount of published literature and the long-term practice of our research group in the field of prevention and control of rockburst,the research progress and shortcomings in understanding the rockburst phenomenon have been comprehensively in-vestigated.This study focuses on the occurrence mechanism and monitoring and early warning technology for rockburst in coal mines.Results showed that the prevention and control of rockburst had made significant progress.However,with the increasing mining depth,several unre-solved concerns remain challenging.From the in-depth research and analysis,it can be inferred that rockburst disasters involve three main problems,i.e.,the induction factors are complicated,the mechanism is still unclear,and the accuracy of the monitoring equipment and multi-source stereo monitoring technology is insufficient.The monitoring and warning standards of rockburst need to be further clarified and im-proved.Combined with the Internet of Things,cloud computing,and big data,a study of the trend of rockburst needs to be conducted.Further-more,the mechanism of multiphase and multi-field coupling induced by rockburst on a large scale needs to be explored.A multisystem and multiparameter integrated monitoring and early warning system and remote monitoring cloud platform for rockburst should be explored and developed.High-reliability sensing technology and equipment and perfect monitoring and early warning standards are considered to be the de-velopment direction of rockburst in the future.This research will help experts and technicians adopt effective measures for controlling rock-burst disasters.

Pentraxin 3 contributes to neurogenesis after traumatic brain injury in mice

Emerging evidence indicates that pentraxin 3 is an acute-phase protein that is linked with the immune response to inflammation.It is also a newly discovered marker of anti-inflammatory A2 reactive astrocytes,and potentially has multiple protective effects in stroke;however,its role in the adult brain after traumatic brain injury is unknown.In the present study,a moderate model of traumatic brain injury in mice was established using controlled cortical impact.The models were intraventricularly injected with recombinant pentraxin 3(the recombinant pentraxin 3 group)or an equal volume of vehicle(the control group).The sham-operated mice underwent craniotomy,but did not undergo the controlled cortical impact.The potential neuroprotective and neuroregenerative roles of pentraxin 3 were investigated on days 14 and 21 after traumatic brain injury.Western blot assay showed that the expression of endogenous pentraxin 3 was increased after traumatic brain injury in mice.Furthermore,the neurological severity test and wire grip test revealed that recombinant pentraxin 3 treatment reduced the neurological severity score and increased the wire grip score,suggesting an improved recovery of sensory-motor functions.The Morris water maze results demonstrated that recombinant pentraxin 3 treatment reduced the latency to the platform,increased the time spent in the correct quadrant,and increased the number of times traveled across the platform,thus suggesting an improved recovery of cognitive function.In addition,to investigate the effects of pentraxin 3 on astrocytes,specific markers of A2 astrocytes were detected in primary astrocyte cultures in vitro using western blot assay.The results demonstrated that pentraxin 3 administration activates A2 astrocytes.To explore the protective mechanisms of pentraxin 3,immunofluorescence staining was used.Intraventricular injection of recombinant pentraxin 3 increased neuronal maintenance in the peri-injured cortex and ipsilateral hippocampus,increased the number of doublecortin-positive neural progenitor cells in the subventricular and subgranular zones,and increased the number of bromodeoxyuridine(proliferation)and neuronal nuclear antigen(mature neuron)double-labeled cells in the hippocampus and peri-injured cortex.Pentraxin 3 administration also increased the number of neurospheres and the number of bromodeoxyuridine and doublecortin double-labeled cells in neurospheres,and enhanced the proliferation of neural progenitor cells in primary neural progenitor cell cultures in vitro.In conclusion,recombinant pentraxin 3 administration activated A2 astrocytes,and consequently improved the recovery of neural function by increasing neuronal survival and enhancing neurogenesis.All experiments were approved by the Animal Ethics Committee of the First Affiliated Hospital of Chongqing Medical University,China on March 1,2016.

Cervical inlet patch-optical coherence tomography imaging and clinical significance

AIM:To demonstrate the feasibility of optical coherence tomography(OCT)imaging in differentiating cervical inlet patch(CIP)from normal esophagus,Barrett'sesophagus(BE),normal stomach and duodenum. METHODS:This study was conducted at the Veterans Affairs Boston Healthcare System(VABHS).Patients undergoing standard esophagogastroduodenoscopy at VABHS,including one patient with CIP,one representative patient with BE and three representative normal subjects were included.White light video endoscopy was performed and endoscopic 3D-OCT images were obtained in each patient using a prototype OCT system.The OCT imaging probe passes through the working channel of the endoscope to enable simultaneous video endoscopy and 3D-OCT examination of the human gastrointestinal(GI)tract.Standard hematoxylin and eosin(H and E)histology was performed on biopsy or endoscopic mucosal resection specimens in order to compare and validate the 3D-OCT data. RESULTS:CIP was observed from a 68-year old male with gastroesophageal reflux disease.The CIP region appeared as a pink circular lesion in the upper esophagus under white light endoscopy.OCT imaging over the CIP region showed columnar epithelium structure,which clearly contrasted the squamous epithelium structure from adjacent normal esophagus.3D-OCT images obtained from other representative patients demonstrated distinctive patterns of the normal esophagus,BE,normal stomach,and normal duodenum bulb.Microstructures,such as squamous epithelium,lamina propria, muscularis mucosa,muscularis propria,esophageal glands,Barrett's glands,gastric mucosa,gastric glands, and intestinal mucosal villi were clearly observed with OCT and matched with H and E histology.These results demonstrated the feasibility of using OCT to evaluate GI tissue morphology in situ and in real-time. CONCLUSION:We demonstrate in situ evaluation of CIP microstructures using 3D-OCT,which may be a useful tool for future diagnosis and follow-up of patients with CIP.

Two-step hydrothermal synthesis of Sn_2Nb2O_7 nanocrystals with enhanced visible-light-driven H_2 evolution activity

We use a two‐step hydrothermal method to successfully synthesize Sn2Nb2O7nanocrystals with an average size of approximately20nm.The as‐obtained samples are characterized by powder X‐ray diffraction,ultraviolet‐visible diffuse reflectance spectroscopy,Brunauer‐Emmett‐Teller analysis,scanning electron microscopy,and transmission electron microscopy.The photocatalytic activity of the Sn2Nb2O7nanocrystals is evaluated by photocatalytic water splitting under visible light irradiation.The Sn2Nb2O7nanocrystals with a large surface area of52.2m2/g show an enhanced visible‐light‐driven photocatalytic H2production activity,approximately5.5times higher than that of bulk Sn2Nb2O7powder.The higher photocatalytic activity of Sn2Nb2O7nanocrystals is mainly attributed to its relatively high dispersity of nanosized particles and larger specific surface area when compared with the bulk powder.

Optimization of three-dimensional boiling enhancement structure at evaporation surface for high power light emitting diode

A theoretical model of phase change heat sink was established in terms of thermal resistance network. The influence of different parameters on the thermal resistance was analyzed and the crucial impact factors were determined. Subsequently, the forming methods including ploughing-extrusion and stamping method of boiling enhancement structure at evaporation surface were investigated, upon which three-dimensional microgroove structure was fabricated to improve the efficiency of evaporation. Moreover, the crucial parameters related to the fabrication of miniaturized phase change heat sink were optimized. The heat transfer performance of the heat sink was tested. Results show that the developed phase change heat sink has excellent heat transfer performance and is suitable for high power LED applications.