中国海洋经济前景预测

中国海洋经济正处于快速发展阶段,加强海洋经济的预测研究将有利于认识海洋经济发展规律、确定全国海洋经济发展目标和实现海洋开发战略目标。文章主要运用趋势外推法和灰色系统理论构建海洋经济预测模型,利用历史统计数据,预测中国海洋经济的发展趋势。     

中国主要人工林树种幼龄材与成熟材及人工林与天然林木材性质比较研究

本文对中国１０种人工林和４种天然林的幼龄材与成熟材及４个树种的人工林木材与天然林木材的构造特征、化学性质、物理性质、力学性质的３３项材性指标差异进行了比较研究。结果表明,在幼龄材与成熟材之间,在统计上表现出差异显著性的为幼龄材比成熟材生长轮宽,管胞列数多,管胞短,直径小,微纤丝角大,密度小,径向干缩小,差异干缩大,流体扩散性高,抗弯强度、抗弯弹性模量、顺纹抗压强度、径面顺纹抗剪强度、径面抗劈力和冲击韧性低等１５项,即４６％的测试项目差异显著;表明在木材加工和用作结构材时应将幼龄材和成熟材视作两个性质不同的总体来考虑,在培育结构材时应研究如何缩短幼年期或改善幼年期材性。在人工林与天然林木材之间,采取人工林幼龄材性质与天然林幼龄材性质相比,人工林成熟材性质与天然林成熟材性质相比,结果表明,多数性质在统计上差异不显著,只有人工林木材比天然林木材胞壁率小、顺纹抗压强度低、差异干缩大、流体扩散性高等４项,即只有１２％的很少数测试项目差异显著;表明有可能通过人工培育的方法培育出与天然林木材性质相近的木材。     

Characteristics of Reproductive Biology for Larix Originating in Japan

SpeciesandDistributionofLarchThereare15specicsofLarixintheworld.Theymainlydistributeinthefrigid-te11lperatezo11coftI1eNortl1cr11Hclnispllcrcandtl1cH'-Jt,asinCI1ina.Tl1crearconI\'.onesPCCiesa11dOI1c.-'.rLtntrtvI1iclldistributci11Japan,l1all1cIy-Japa11cseIarcl1(Larirk'len1liferiCarr.)a11dDahurianlarcl1(LarirgIneli)1iivar../al)o11i`xIPiIgcr).JapaIlcscIarcl1distributcsi11al1arrotvarca.OI1l}'i11tIlcalpil1cinHOI1sllu.Tl1cnortl1ofl1orizol1taldistributionisi11MiyaglCouIll}'(alt.l56511…     

除湿机降低小麦面层水分的试验

利用除湿机降低粮仓内小麦的面层水分含量,可将其降至安全水分范围,且前期除湿效率显著高于后期。对小麦面层水分含量与仓内相对湿度做相关性分析,发现二者存在良好的线性关系(R2>0.9),在知道其中一个变量的情况下,可通过回归方程对另一个变量进行预测。通过对传统除湿和除湿机除湿的成本进行比较,发现利用除湿机除湿不仅可以降低成本,还能降低工作强度,提高工作效率。     

水稻吸钾规律与钾素平衡的研究

黑龙江省水稻生长的实体模型,对两种不同类型的水稻土钾素养分变化进行模拟试验．结果表明,水稻对钾素吸收呈“山峰”式积累曲线;钾素在作物库内积累分布：茎秆＞叶片＞籽实＞根系;土壤库中速效钾动态变化趋势,以抽穗期为界限,前期略高于后期;土壤库内钾素的输出大于输入,属亏损型管理,盈亏量与施肥量呈“单谷状”曲线分布;以图解法求出钾素平衡时的施钾量．同时提出补给土壤库中钾素含量的对策．     

生态资源赋能乡村共富——数字经济的促进作用

为探究数字经济在生态资源赋能乡村共富中的促进作用,基于空间异质性,构建“生态资源-数字经济-乡村共富”的分析框架,利用2010—2020年省级面板数据,采用地理探测器工具进行了实证研究。结果表明:1)生态资源价值对乡村共富具有驱动作用。其中,森林资源、草原资源、自然保护区资源通过生态经济化促进城乡财富转移,而政府保护治理投资和污水再利用则保障乡村分享生态资源价值化红利的可持续性。2)数字经济对乡村共富具有驱动作用。主要来源于数字经济通过赋能农业生产、丰富产业发展模式、重构人力资本积累方式和推动统一大市场建设等途径直接或间接促进要素从城市向乡村流动,缓和发展不平衡不充分的问题。3)生态资源价值和数字经济的交互作用对乡村共富具有显著驱动作用。这主要源于数字经济赋能生态资源的产权界定过程,以及价值核算、开发建设、市场交易和利益分配等产权实施过程,促进生态产品价值实现,使其真正变成生态产业,进而促进乡村共富。因此,从推动乡村数字化发展,构建生态资源监管、开发、交易平台以及促进数字经济赋能生态资源价值实现等三方面提出政策建议。     

Variability of the seeds and cones and key taxonomic characters selection ofLarix in Northeast China

The paper presents the results of biometrical study of the seeds and cones of larch taxa from Northeast of China. Fourteen characters are considered and their analyses showed that the seeds and cones of the larch taxa were relative greatly variable. Cluster analysis and principal component analysis for all 6 larch taxa were made. The analysis results proved that the dominant larch population in Toudao Farm fell within the range of variation ofLarix olgensis. The key taxonomic characters are the length of seed wing, length of cone, length of seed, the length/width ratio of seed and number of scales. This research was supported by Natural Science Foundation of Heilongjiang Province.(C9515) Responsible Editor: Chai Ruihai     

南海海洋生态安全及渔业可持续发展研究

随着环南海地区的经济发展及我国向南海进军步伐的不断加快,不合理的人类涉海活动,导致一系列难以逆转的海洋生态安全问题随之而来,制约着南海渔业的健康发展。依据相关文献资料,在已有研究成果的基础上,阐述海洋生态安全的概念,探讨南海海洋生态安全与渔业可持续发展的关系,分析南海海洋生态安全问题的深层原因,提出提升公民的海洋生态安全意识及治理能力、健全海洋生态安全管理制度、完善海洋生态安全法律体系和建立海洋生态安全多元化投融资体系等保护南海海洋生态安全的对策,以实现南海渔业可持续发展。     

Soil aggregate characteristics and stability of soil carbon stocks in a <Emphasis Type="Italic">Pinus tabulaeformis</Emphasis> plantation

Pinus tabulaeformis has been widely planted in order to conserve soil and water and improve the ecological environment in China. This study aimed to unravel how soil aggregates and soil carbon (C) stock stability of a P. tabulaeformis plantation change after 60 years of natural development and was performed in Vitex negundo var. heterophylla and Ziziphus jujuba var. spinosa shrub (shrub), a P. tabulaeformis forest (pine), and a coniferous broadleaf P. tabulaeformis mixed forest (pine-oak). Afforestation increased the stability of soil aggregates in the 0–10 cm soil layer but resulted in a decrease in the 10–20 cm soil layer. However, the presence of deciduous broadleaf species in the pine plantation improved the stability of soil aggregates. The total soil C stock was increased by afforestation, especially in the pine-oak forest, where it reached a significant level. The mineral soil C stock in the shrub stand was higher than that in pine and lower than that in pine-oak forests, but the C fractions had a different change. Afforestation increased the C fraction of macroaggregates in the 0–10 cm soil layer but decreased it in the 10–20 cm soil layer. This result suggested that afforestation could improve soil C stabilization in deeper soil. However, the pine-oak forest had a higher C fraction of macroaggregates than the pine forest in the 10–20 cm soil layer, indicating that soil C stabilization of the P. tabulaeformis plantation decreased when deciduous broadleaf species were present and thus formed the coniferous broadleaf mixed forest.     

圆锯片组合分块切削木工成形刀具的设计

为解决小型台式木工机床对硬质木材开榫槽困难的问题,设计了一款以圆锯片和平垫组成的木工成形刀具.圆锯片的齿刃廓形采用大前角的带锯锯齿,安装时锯齿刃沿刀轴排列成大刃倾角等技术,可降低切削力和切削冲击,切削轻快,、噪音小、寿命稳定可靠.使用结果表明,分块式切削刃的木工成形刀具的切削力小且平稳,无论是硬、软质木材铣槽的进料速度均可提高3倍以上.