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马尾松应压区与对应区制浆性能的比较 被引量:5
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作者 高慧 牛敏 +1 位作者 张利萍 刘盛全 《东北林业大学学报》 CAS CSCD 北大核心 2010年第2期42-44,共3页
以马尾松应压区、对应区和侧区为研究对象,分析比较它们的化学组成、纤维形态和制浆性能。研究结果表明:应压区的木质素质量分数最高,综纤维素和纤维素质量分数都最低,苯醇抽出物、1%NaOH抽出物、冷水和热水抽出物都最低。3区对纤维素... 以马尾松应压区、对应区和侧区为研究对象,分析比较它们的化学组成、纤维形态和制浆性能。研究结果表明:应压区的木质素质量分数最高,综纤维素和纤维素质量分数都最低,苯醇抽出物、1%NaOH抽出物、冷水和热水抽出物都最低。3区对纤维素质量分数的影响极显著,对木质素质量分数的影响较显著,对综纤维素质量分数的影响不显著。应压区的纤维平均长度最小,应压区的长宽比比对应区大,壁腔比比对应区和侧区小。3区对纤维平均长度、晚材的长宽比和壁腔比的影响极显著,对早材的壁腔比影响较显著,对早材的长宽比影响不显著。在相同制浆条件下,应压区的制浆得率比对应区和侧区低,浆料卡伯值比对应区和侧区高,浆料黏度比对应区和侧区小;应压区纸张抗张指数、撕裂指数和耐破指数在3区中都最小。与对应区和侧区相比,应压区在化学制浆性能上还存在一定缺陷。 展开更多
关键词 马尾松 应压区 化学组成 制浆性能
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考虑采空区压实效应的沿空掘巷煤柱设计方法研究 被引量:12
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作者 冯友良 《中国安全生产科学技术》 CAS CSCD 北大核心 2021年第11期53-59,共7页
为建立1种相对科学的沿空掘巷煤柱尺寸设计方法,采用理论与数值试验研究、现场试验等手段,基于采空区压实效应,分析各尺寸煤柱沿空掘巷掘采全过程围岩应力分布与变形。研究结果表明:采空区压实效应模拟研究方法能够模拟采空区应力恢复;... 为建立1种相对科学的沿空掘巷煤柱尺寸设计方法,采用理论与数值试验研究、现场试验等手段,基于采空区压实效应,分析各尺寸煤柱沿空掘巷掘采全过程围岩应力分布与变形。研究结果表明:采空区压实效应模拟研究方法能够模拟采空区应力恢复;掘巷过程中,煤柱内应力由小到大依次为:工作面倾向水平应力、工作面推进方向水平应力、垂直应力,在小尺寸煤柱内呈偏向采空区一侧的单峰分布,小尺寸煤柱逐渐向大尺寸煤柱过渡期间,内部应力量值开始比原岩应力小,随后逐渐增加至出现一定的应力集中,而实体煤帮中峰值应力不断降低,位置逐步向巷帮转移;受超前采动作用后,更大面积的煤柱会受高应力作用,大尺寸煤柱内垂直及水平应力集中系数逐步提高,工作面倾向的高应力区范围更广,当煤柱宽度不超过一定数值时,内部应力大小均低于掘巷过程中相应数值,大煤柱则具有相反的规律,实体煤帮中应力集中系数与掘巷时相比更大,峰值点向围岩深处进一步转移;研究结果通过工程实践检验,可为合理煤柱尺寸设计提供1种新的方法。 展开更多
关键词 沿空掘巷 煤柱尺寸 采空实效 采动 数值模拟
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Synthesis Scheme for Low Power Designs Under Timing Constraints 被引量:5
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作者 王玲 温东新 +1 位作者 杨孝宗 蒋颖涛 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2005年第2期287-293,共7页
To minimize the power consumption with resources operating at multiple voltages a time-constrained algorithm is presented.The input to the scheme is an unscheduled data flow graph (DFG),and timing or resource constrai... To minimize the power consumption with resources operating at multiple voltages a time-constrained algorithm is presented.The input to the scheme is an unscheduled data flow graph (DFG),and timing or resource constraints.Partitioning is considered with scheduling in the proposed algorithm as multiple voltage design can lead to an increase in interconnection complexity at layout level.That is,in the proposed algorithm power consumption is first reduced by the scheduling step,and then the partitioning step takes over to decrease the interconnection complexity.The time-constrained algorithm has time complexity of O(n 2),where n is the number of nodes in the DFG.Experiments with a number of DSP benchmarks show that the proposed algorithm achieves the power reduction under timing constraints by an average of 46 5%. 展开更多
关键词 low power multiple supply voltages partitioning timing constraints SCHEDULING
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Test and application of hydraulic expansion bolts in a roadway under goaf with ultra-close separation 被引量:4
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作者 Wang Xiangyu Bai Jianbiao +1 位作者 Guo Guanlong Yu Yang 《International Journal of Mining Science and Technology》 SCIE EI 2014年第6期839-845,共7页
The roof of a roadway under goal with ultra-close separation consists of thin rock strata and rocks caving in upper goal. Influenced by the mining of the upper coal seam, the roof is loose and broken, and its integ- r... The roof of a roadway under goal with ultra-close separation consists of thin rock strata and rocks caving in upper goal. Influenced by the mining of the upper coal seam, the roof is loose and broken, and its integ- rity is poor. Resin anchored bolts cannot provide an effective anchoring force in such roof conditions. By conducting free expansion tests and field pull-out tests on a hydraulic expansion bolt, this study has ana- lyzed the influencing factors and laws of radial expansion and anchoring force changes in the rod body. This has revealed the anchoring mechanism of such bolts, and has obtained reasonable water injection pressures and suitable drilling diameters (which are 20-25 MPa and 32-35 mm respectively) for the hydraulic expansion bolt (cR28 mm) used in these tests. Based on pull-out tests at different interlayer spacing, the applicability of hydraulic expansion bolts had been verified for controlling the roof of road- ways under goal with ultra-close distance. Combined with the deformation and failure characteristics of the test roadway roof, this paper proposes a united roof-control technology based on the use of hydraulic expansion bolts and advancing intubation for the roof. Engineering practice indicated that the roof of the test roadway did not generate leaking and caving phenomenon, and the amount of roof deformation was controlled to within 150 mm. Maintenance of the roadway roof has been improved significantly, which ensures safe mining in coal seams with ultra-close separation. 展开更多
关键词 Hydraulic expansion bolt Coal seams with ultra-close distance Anchoring force Roadway under goaf
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Distribution pattern of front abutment pressure of fully-mechanized working face of soft coal isolated island 被引量:16
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作者 Xu Wenquan Wang Enyua +2 位作者 Shen Rongxi Song Dazhao Zhang Jingmin 《International Journal of Mining Science and Technology》 2012年第2期279-284,共6页
The front abutment pressure of a fully-mechanized workface of 11061 soft coal isolated island of Liangbei Coal Mine was measured and studied using a self-developed mining-induced stress monitoring system associated wi... The front abutment pressure of a fully-mechanized workface of 11061 soft coal isolated island of Liangbei Coal Mine was measured and studied using a self-developed mining-induced stress monitoring system associated with electromagnetic radiation technology, and the effects of abutment pressure distribution on strata behavior we discussed. The results indicate that the miningdnduced influencing distance advanced at the fully-mechanized working face of soft coal isolated island is larger than that at the gen- eral working face at the isolated island, besides the fracture zone in front of working face was widened to some extent, and the influencing range caused by relaxations on both roadways became bigger with the advancing working face. Moreover, it can be indicated that mining has significant effect on strata behav- ior of fully-mechanized working face of soft coal isolated island, which is mostly distributed in the area of stress concentration. The research results have an important reference value for revealing the distribution pattern of the front abutment pressure of a fully-mechanized working face of soft coal isolated island, and controlling the coal-rock dynamic disaster occurrence under similar mining conditions. 展开更多
关键词 Soft coalIsolated islandFully-mechanized working faceAbutment pressureCoal-rock dynamic disaster
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CLINICAL OBSERVATION ON ACUPOINT DIGITAL PRESSING FOR TREATING IRRITABLE SYMPTOMS AND SIGNS OF POSTOPERATION OF MYOPORTHOSIS
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作者 王晓阳 《World Journal of Acupuncture-Moxibustion》 2002年第3期48-50,共3页
Objective: To explore a new effective approach for treatment of the local irritable symptoms and signs resulted from myoporthosis operation. Methods: 263 cases of radial keratotomy outpatients were divided into contro... Objective: To explore a new effective approach for treatment of the local irritable symptoms and signs resulted from myoporthosis operation. Methods: 263 cases of radial keratotomy outpatients were divided into control group (n=49, 90 eyes) and treatment group (n=214, 412 eyes). Patients of control group were treated with 0.5% Chloramphenicol eye drops, 3 times daily, 1-2 drops/time, and with 0.5% Erythromycine eye ointment every night. In treatment group, patients were treated with acupoint and hand reflection area digital pressing method except with the same eye drops and eye ointment. Body acupoints used were Cuanzhu (BL 2), Yuyao (EX HN 4), Sizhukong (TE 23), Sibai (ST 2) and Taiyang (EX HN 5). The hand reflex areas used were Eye Area, Liver Area, Kidney Area, Spleen Area, Heart Area and Lung Area. Five days constituted a therapeutic course. Results: Following 3 courses (15 days) of treatment, the markedly effective rate and total effective rate of treatment group and control group were 74.51% and 38.89%, 94.17% and 66.67% respectively. There was a significant difference between two groups in the total effective rate (P<0.05), showing the therapeutic effect of treatment group being better than that of control group. Conclusion: Acupoint digital pressing is rather effective in treatment of myoporthosis post operation irritable symptoms and signs. 展开更多
关键词 Post operation symptoms of myoporthosis Acupoint digital pressing treatment Body acupoints and hand reflex areas
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