Research advance in forest restoration on the burned blanks

How to restore the destroyed forest after forest fire is a key question that man must face. This paper reviewed the research situation and history on the forest restoration burned blanks and summed up the research methods used into four scales: seed-bank scale, community scale, ecosystem scale and landscape scale. The new technologies such as GIS & Remote Sensing used to vegetation restoration were also summarized. The strategies and developing trend of vegetation restoration research on burned blanks were discussed.

Landscape change on burned blanks in Daxing'an Mountains

Daxing抋n Mountains was one of the most important forest areas in China, but it was also an area which was prone to suffering forest fire. The catastrophic forest fire that occurred in Daxing抋n Mountains on May 6, 1987 devastated more than 1.33?06 hm2 of natural forests, which leaded to the formation of some mosaic areas with different burn intensities. Two forest farms of Tuqiang Forest Bureau (124?5-122?8E, 53?4-52?5N) were chosen as a typical area to analyze the post-fire landscape change by drawing and comparing the two digital forest stand maps of 1987 and 2000. The landscape lands of forest were classi-fied into 12 types: coniferous forest, broadleaf forest, needle-broadleaf mixed forest, shrub, nursery, harvested area, burned blanks, agricultural land, swamp, water, built-up, grass. The results showed that: 1) The burned blanks was almost restored, some of them mainly converted into broadleaf forest land during the process of natural restoration, and coniferous forest land by the artificial re-forestation, and the others almost changed into swamp or grass land; 2) The proportion of forest area increased from 47.6% in 1987 to 81.3% in 2002. Therefore, a few management countermeasures, such as the enhancing peoples consciousness of fire-proofing and constructing species diversity, were put forward for forest sustainable development.

Theoretical prediction and experimental investigation on formability of tailor-welded blanks

Based on the elastoplastic mechanical properties of the weld and heat affected zone metals obtained by a nanoindentation test, a theoretical calculation model was established for the forming limit diagram（FLD） of tailor-welded blanks（TWBs） on the basis of plastic constitutive relations and Hosford yield criteria. Hemispherical punch bulging tests were performed to verify the FLD theoretical calculation results. The results demonstrated that not only the FLD theoretical calculation of base materials but also that of TWBs had a good agreement with their experiments. Besides, poorer formability of TWBs caused its FLD significantly lower than that of base materials. The theoretical calculation model offers a reliable approach to obtain the specific FLD of TWBs.

Determination of Elastoplastic Mechanical Properties of the Weld and Heat Affected Zone Metals in Tailor-Welded Blanks by Nanoindentation Test

The elastoplastic mechanical properties of the weld and heat affected zone metals have comparatively major impact on the forming process of tailor-welded blanks. A few scholars investigated the elastoplastic mechanical properties of the weld and heat affected zone, but they only simply assumed that it was a uniform distribution elastoplastic material different from the base materials. Four types of tailor-welded blanks which consist of ST12 and 304 stainless steel plates are selected as the research objects, the elastoplastic mechanical properties of the tailor-welded blanks weld and heat affected zone metals are obtained based on the nanoindentation tests, and the Erichsen cupping tests are conducted by combining numerical simulation with physical experiment. The nanoindentation tests results demonstrate that the elastoplastic mechanical properties of the weld and heat affected zone metals are not only different from the base materials, but also varying between the weld metals and the heat affected zone metals. Comparing the Erichsen cupping test resulted from numerical with that from experimental method, it is found that the numerical value of Erichsen cupping test which consider the elastoplastic mechanical properties of the weld and heat affected zone metals have a good agreement with the experimental result, and the relative error is only 4.8%. The proposed research provides good solutions for the inhomogeneous elastoplastic mechanical properties of the tailor-welded blanks weld and heat affected zone metals, and improves the control performance of tailor-welded blanks forming accuracy.

Preparation of heat-resistant aluminum alloy pipe blanks by multi-layer spray deposition

A heat resistant aluminum alloy pipe blank with dimensions of d 700/300 mm×1 200 mm was prepared by the multi layer spray deposition technology. Optical microscopy, X ray diffractometry and transmission electron microscopy were used to analyze its morphologies and microstructures. The results show that the microstructures of the pipe blank are homogeneous and the precipitates are uniformly distributed d 25～70 nm spherical or sphere like Al 12 (Fe,V) 3Si particles, its mechanical properties at room temperature and 350 ℃ after densification by extrusion are σ b=412 MPa, δ =7.6% and σ b=187 MPa, δ =7.6%, respectively. The analyses indicate that the proper match of the motion rates of atomizer and substrate can produce deposited blanks with uniform thickness and relatively high cooling rate.

Teflon-pad shaping process of circular metal blanks into quasi-cup specimens by theoretical and experimental methods

Teflon-pad shaping process of circular metal blanks into quasi-cup specimens is investigated by theoretical and experimental methods in the quasi-static condition. In the experiments, circular metal sheets are formed into the quasi-cup samples by compressing them between a Teflon-filled die and a rigid punch with desirable shape. To investigate influences of different parameters on the forming progress, 12 rigid punches with different dimensions, two blank material types of aluminum and galvanized iron, three blank thicknesses of 0.6, 1.1 and 1.5 mm, and two Teflon-fillers of PVC and polyurethane are used in several experimental tests. In the analytical part, theoretical deformation models of metal blank and Teflon-filler are introduced and based on energy method, energy absorptions by the blank and Teflon-filler are calculated to derive a theoretical formula for predicting total required energy of the forming process. For this purpose, several energy absorption mechanisms are considered in the blank and filler. Furthermore, predictions by theoretical equation are compared with the corresponding experimental tests to study the verity of the calculated formulas. Theoretical and experimental results illustrate change trend of forming energy with respect to blank thickness. Also, the performed forming tests show that when external cone angle of rigid punch with respect to the horizontal direction increases, forming energy increases nonlinearly; and when the depth of spherical part of rigid punch increases, the probability of rupture increases. Additionally, the experiments demonstrate that there is a direct relationship between the forming energy and flow stress of the blanks. Furthermore, experimental observations illustrate that forming energy of a certain blank with PVC Teflon-filler is higher than that of a similar specimen with polyurethane Teflon-filler; but, the probability of wrinkling decreases when PVC Teflon-pad is used as the filler; and it is advantage of PVC Teflon-filler with respect to polyurethane Teflon.

Joint Performance for Laser Cutting-welding of Zinc-coated Tailored Blanks

The process of laser bull welding of zinc-coated steel（SGCD3 and WLZn）blanks was presented.whose edges were prepared by laser cutting.The properties of the butt joints.such as tensile strength.bending,stamping.weld shape,and corrosion-resisant were tested.The experiments of laser cutting and welding were carried ont on a custom-made system designed.which is a set of equipment for wide sheet butt welding based on a laser cutting-welding combination process.The experiments proved the technological feasibility of laser butt welding for thin zinc coated steel sheets whose edges were prepared by laser cutting on the same equipment.

Behaviour of Friction Stir Dissimilar Welded Blanks and The Role of Different Tool Pin Profiles

In this study,the forming behaviour of dissimilar welded blanks was studied.Welded blanks were prepared with friction stir welding processwith different types of tool pin profiles.Welded blanks were developed with fixedfriction stir welding process parameters by varying the tool pin profiles.The forming behaviour of welded blanks were analyzed with the limiting dome height test in biaxial stretch forming condition.The results reveal that the formability of welded joints are made with the square pin tool exhibited a better formabilitybehaviour when compared with other profiled tools,this is due to sufficient amount heat generation and high static volume to dynamic volume ratio.

Research on horizontal electromagnetic continuous casting of copper tube blanks

The effect of commercial frequency electromagnetic field on the solidification structure and mechanical propertiesof copper hollow blanks prepared by horizontal continuous casting method was investigated. The results show thatwhen the electromagnetic field is imposed, columnar grains are evidently refined and fine equiaxed grains areobtained in the inner side of the cross-section. Moreover, with the increase of input current, the equiaxed grain regionwidens and the grains distribute more uniformly in the circumferential direction. Meanwhile, the mechanical properties areremarkably improved by the application of electromagnetic field. When the input current is 140 A, the tensile strengthincreases 15% and the elongation increases 10%. However, the electromagnetic field has no effect on the distribution ofmicroelements.

Preparation of tube blanks by atomization deposition process

By using the method of mathematical calculation combined with experiment, the technological conditions of atomization deposition process for making tube blanks with even thickness were studied. The results show that in the case of the substrate rotating and translating simultaneously, when the ratio of the rotation frequency to the translational velocity is very large, and the other deposition conditions are suitable, tube blanks with even thickness and high density can be produced, and the actual deposition efficiency will be highest.

Application of Blank Symbols in Japanese Architecture and Indoor Designs

A symbol is an expression of meaning,while blank symbols express special meanings.By focusing on the application of blank symbols in Japanese architecture and indoor designs,we analyzed the aesthetic principles in Japanese architecture and indoor designs from the perspective of semiotics,such as“Kongji,”“Emptiness,”and“Dying out,”and their minimalist and pure design concepts.Traditional Chinese culture was also further explored,especially the profound influence of the“Chan sect”and the philosophy of“unity of heaven and mankind”on Japanese architecture and designs.This study aims to facilitate the coexistence and mutual appreciation of Chinese and Japanese architectural designs.

火锅菜盆复合模设计

根据火锅菜盆的尺寸、结构和材料厚度,对其冲压工艺进行分析,并设计了“落料+第1次成形+拉深”复合模、第2次成形单工序模、侧冲孔单工序模。在复合模中,120°的斜边可视为拉深工序的压边圈,将第1次成形120°夹角的工序排在拉深工序前。在第2次成形70°夹角的单工序模的下模中设计了活动顶板,与上模的成形凸模将120°的斜边压住,防止120°的斜边变形。在“落料+第1次成形+拉深”复合模和第2次成形单工序模中,在下模成形零件的底部设置橡胶垫块,在上模向下运动时橡胶垫块的弹力将材料顶住,同时给上模向下运动腾出空间,防止模具零件卡死。

留白在极简主义摄影中的应用与审美研究

留白是中国画独特的创作哲学。通过对中国画中留白的作用和留白在极简主义摄影中的应用研究,探讨留白在极简主义摄影中的审美价值。留白的巧妙运用不仅让极简主义摄影的美学价值最大化发挥,而且是中国审美文化的传承。从中国传统美学中汲取创作灵感,有助于推动极简主义摄影的创新与发展,为现代摄影多元化发展提供新思路。

前箱熔体温度对8011铝合金铸轧板坯组织性能的影响

为了稳定提高双零铝箔用铸轧坯料质量,使用电解铝液配料生产规格为7.0 mm×1300 mm的8011铝合金铸轧铝板卷,并利用光学显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)及电子万能拉伸试验机等手段,研究了不同前箱铝熔体温度(680,690,700,710℃)对8011铝合铸轧板坯微观组织和力学性能的影响.结果表明:随着前箱熔体温度的升高,铸轧板坯晶粒的尺寸呈略微增大再急剧变大的趋势,其抗拉强度和断后伸长率均呈先缓慢降低后急剧下降的趋势;当前箱熔体温度控制在680~700℃时,可获得综合力学性能较佳的铸轧板坯,其平均纵向抗拉强度和横向抗拉强度分别不低于141.87 MPa和138.84 MPa,平均纵向断后伸长率和横向断后伸长率分别不低于29.8%和26.4%.

融合裂缝形态信息的电阻率测井成像图空白条带填充方法

电阻率测井成像图中存在宽度和位置不定的空白条带,而目前常用的空白条带反距离加权插值填充法仅依靠像素点距离参数计算插值,往往导致填充后区域与实测区域纹理不连贯,纹理易呈现直线状,与实际状况不符。为此,将裂缝区域形态与分布信息作为参量,构建插值计算模型,形成融合裂缝形态分布信息的空白条带填充法。该填充算法能根据插值点与裂缝形态拟合线的相对位置关系,动态调整参考点对插值点插值的权重系数,填充后的裂缝区域纹理连贯平滑,更符合裂缝实际形态和分布的规律。实际测井数据应用表明,相较于传统填充方法,采用该方法填充后的裂缝分布拟合线与霍夫变换后曲线相似度提升25%以上,不连贯填充点数量下降88%以上,性能提升明显。该方法的应用成果可为后续测井图像中各种裂缝的智能识别和精确分割提供更好的数据支撑。

论“X一代”亚裔美国诗歌之创新性诗学实践

20世纪80年代至今,“X一代”亚裔美国诗人一直活跃在美国诗坛,积极进行诗歌形式与风格的创新,丰富了当代英语诗歌的语言表征和美学表达。本文聚焦于“X一代”亚裔美国诗歌中的创新性诗学实践,考察亚裔美国诗歌的语言创新、碎片化叙事,以及“空白”的视觉呈现。这些实践突破了既定的语言规范,革新了诗歌的视觉效果,既再现了亚裔美国人复杂的移民历史和族裔经验,又挑战了美国社会固有的权力关系,为亚裔美国诗歌发展赋予了新的美学意义和现实意义。

现代椅类家具装饰中的空符号设计研究

现阶段实用与美观的家具设计意识在不断地被深耕中,对于设计意境、内涵的追求成为许多高附加值家具产品的重要特征,本研究针对现代椅类家具装饰中的空符号视觉要素进行分析探索,使空符号的设计语言能够丰富家具外在表现形式、增加家具内在意义内容。依据点、线、面、体的划分标准,对空符号视觉要素进行分类并分别论述其视觉特征和装饰效果,同时结合椅类家具造型结构特点,探讨空符号位于不同位置范围、不同视觉元素组合形式中的特点及作用,生成对现代椅类家具装饰中空符号设计语言的形式与功能的整体认知,从而为现代椅类家具设计提供思考方向。

一种商业合版印刷满版成品离线自动分离的拼版方法

针对商业合版印刷无法适应满版成品离线自动分离设备的要求,探索并提出一种能实现满版成品离线自动分离的拼版方法。根据满版成品离线自动分离设备的工作原理,给出成品自动分离要求,然后依据成品自动分离要求,利用Adobe Illustrator和TongYin PDF Expert软件完成产品拼版。实例分析结果表明,相较于人工成品分离,所实现的满版成品离线分离提升了近2倍的工作效率,同时也减少了2/3的人员需求;相较于拆标机,满版成品离线自动分离设备的生产效率提高了1倍,且换版时间不超过5 min。此方法为实现商业合版印刷成品的自动分离提供了新的解决方案,带来显著的效率提升和成本降低。

基于锥形回转体多孔毛坯的异型面结构加工工艺研究

为研究在锥形回转体多孔毛坯基础上加工出异型面结构,论文首先对产品进行了工艺分析,通过基础试验,对比了铣削加工、电火花加工、电解加工后试片的表面形貌以及渗透性。在此基础上,制定了产品的加工工艺,通过流量试验,验证了工艺方法的有效性,为该类产品的加工提供了有益的参考。

425/630 mm超宽铜带坯一次性连续挤压技术及质量控制

研究了425/630 mm超宽紫铜带一次性连续挤压工艺,并对成型过程进行了模拟。结果表明:通过一次性连续挤压成型的425 mm超宽铜排组织均匀细小,抗拉强度平均值大于210 MPa,性能较理想,适合后续进行大变形量压延加工;通过对630 mm超宽铜排一次性连续挤压模型数值模拟,计算得到的理论值与Deform-3D软件模拟结果基本一致。