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United States Secret War in Laos: Long-Term Environmental and Human Health Impacts of the Use of Chemical Weapons
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作者 Kenneth R. Olson David R. Speidel 《Open Journal of Soil Science》 CAS 2023年第4期199-242,共44页
In 1959, the United States Central Intelligence Agency (CIA) operation, against the Pathet Lao insurgences and Viet Mien military troops and supply route, began. The Ho Chi Minh Trail was developed after the North Vie... In 1959, the United States Central Intelligence Agency (CIA) operation, against the Pathet Lao insurgences and Viet Mien military troops and supply route, began. The Ho Chi Minh Trail was developed after the North Vietnam government and military decided to reunify South and North Vietnam. The People’s Army of Vietnam (PAVN) then connected the old trails leading from North Vietnam panhandle southward into eastern Laos, Cambodia and South Vietnam. Starting from Hanoi, the primary trail turned southwest into Laos and eastern Cambodia before branching into South Vietnam. Beginning in 1960s, the volume of traffic on the network of trails expanded significantly, but it still took more than a month’s march, by foot and bicycle, to travel from North to South Vietnam. Ho Chi Minh Trail traffic was impacted by repeatedly by Royal Laotian Air Force (RLAF), which was supported by US Air Force tactical herbicide spraying (Operation Ranch Hand program), and US Air Force bombing runs. By the late 1960s, the trail was improved and could accommodate heavy trucks in some sections and was used to supply the annual needs of over one hundred thousand regular PAVN troops active in South Vietnam. By 1974, the trail was a well-marked series of jungle roads (some of them paved) with underground support facilities such as hospitals, fuel-storage tanks, and supply caches with weapons. The Ho Chi Minh Trail was the major supply route for PAVN forces that overran Republic of Vietnam (RV) forces in 1975 and unified Vietnam. The primary objective of this paper is to determine the environmental and human health impacts of RLAF and US Air Force secret spraying of tactical herbicides on Ho Chi Minh Trail in Laos. 展开更多
关键词 Ho Chi Minh Trail laos Cambodia North Vietnam South Vietnam Agent Orange Agent Blue Dioxin TCDD Arsenic Cloud Seeding Mud Making
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Review and Analysis: United States Cluster Munitions and Unexploded Ordnance Left in Laos after the Second Indochina War
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作者 Kenneth R. Olson 《Open Journal of Soil Science》 2023年第8期355-369,共15页
Cluster munitions release dozens of smaller bomblets that rain deadly ammunition on armored tanks, vegetation and troops, effectively striking broad areas of war zone landscapes in one launch. However, only about 60% ... Cluster munitions release dozens of smaller bomblets that rain deadly ammunition on armored tanks, vegetation and troops, effectively striking broad areas of war zone landscapes in one launch. However, only about 60% of bomblets detonate immediately and those that fail to detonate fall to the ground and can lie dormant for years. The legacy of cluster munitions in Laos from the Second Indochina War is unexploded bomblets across the landscape that unexpectedly detonate years later, injuring and killing children, farmers, and other civilians long after the war is over. In Laos, the United States (US) military operation against the Ho Chi Minh Trail, a network of foot and bicycle paths, waterways, and truck routes along the Laos, Cambodia and Vietnam borders linking North and South Vietnam began in 1959. By the 1960s, as the war escalated, trail traffic was interdicted frequently by CIA and US Air Force using tactical herbicide spraying to defoliate dense vegetation and bombing to disrupt supplies and North Vietnamese troops dispersed along the 16,000-kilometer trail. Unexploded ordinance (UXO), including cluster munitions, from U.S. bombings continued in recent years to detonate, kill, maim and injure Laotians and render agricultural lands too hazardous to cultivate. The primary objectives of this study are to document: 1) the long-term consequences and impacts of the US Air Force bombing of Laos during the Second Indochina War (1959 to 1973);2) the United States removal of unexploded ordnance and cluster munitions;and 3) worldwide relief efforts to help the Laotians maimed by unexploded ordnance and cluster munitions. 展开更多
关键词 Cluster Munitions ORDNANCE BOMBS laos Cluster bomblets US Air Force Air America
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以Eu^(3+)为荧光探针研究(LaO)_3BO_3的结构 被引量:5
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作者 彭夷安 李其华 +1 位作者 林建华 郭凤瑜 《中国稀土学报》 CAS CSCD 北大核心 1995年第3期218-222,共5页
利用多晶X射线衍射法研究了(LaO)_3BO_3合成的工艺条件和结构。以少量Li_2CO_3作助熔剂可在较低温度和较短反应时间内制备出(LaO)_3BO_3纯物相。(LaO)_3BO_3属单斜晶系,空间群为P2_1/... 利用多晶X射线衍射法研究了(LaO)_3BO_3合成的工艺条件和结构。以少量Li_2CO_3作助熔剂可在较低温度和较短反应时间内制备出(LaO)_3BO_3纯物相。(LaO)_3BO_3属单斜晶系,空间群为P2_1/m或P2_1。根据Eu ̄(3+)荧光光谱以 ̄5D_0→ ̄7F_2电偶极跃迁为主及 ̄5D_0→ ̄7F_J(J=0、1、2、3、4)跃迁的谱峰数并结合空间群中各个等效点的对称性,推断La ̄(3+)在(LaO)_3BO_3中所处格位的点对称件为C_1或C_s。 展开更多
关键词 (lao)3BO2 晶体结构 荧光探针
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团簇LaO的理论研究 被引量:2
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作者 顾广颐 丁迅雷 代兵 《原子与分子物理学报》 CAS CSCD 北大核心 2005年第4期629-633,共5页
采用密度泛函理论研究LaO团簇体系。中性分子LaO的基态是两重态(2Σ),阴离子LaO-和阳离子LaO+的基态都是单重态(1Σ)。使用不同的方法计算团簇LaO的电子亲和能和电离能。计算结果表明用BLYP方法和弥散极化基组计算结果和实验数据吻合较... 采用密度泛函理论研究LaO团簇体系。中性分子LaO的基态是两重态(2Σ),阴离子LaO-和阳离子LaO+的基态都是单重态(1Σ)。使用不同的方法计算团簇LaO的电子亲和能和电离能。计算结果表明用BLYP方法和弥散极化基组计算结果和实验数据吻合较好。用含时密度泛函理论计算团簇LaO的低能激发态,从理论上归属LaO-的光电子能谱的谱峰和LaO的吸收光谱的谱峰。计算得到与实验一致的结果。 展开更多
关键词 lao团簇 密度泛函理论 含时密度泛函理论 激发态
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新半金属Fe_2LaO_4磁电性能的第一性原理计算 被引量:2
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作者 刘俊 陈希明 董会宁 《无机化学学报》 SCIE CAS CSCD 北大核心 2007年第11期1857-1863,共7页
利用基于密度泛函理论的第一性原理赝势法设计并优化了含稀土元素的新半金属Fe2LaO4。详细计算了其电荷分布,分子磁矩等磁电性能,并结合配位场理论分析了其电子结构。结果表明,Fe2LaO4是一种含稀土元素的铁磁性的新ⅡB型半金属;它的稳... 利用基于密度泛函理论的第一性原理赝势法设计并优化了含稀土元素的新半金属Fe2LaO4。详细计算了其电荷分布,分子磁矩等磁电性能,并结合配位场理论分析了其电子结构。结果表明,Fe2LaO4是一种含稀土元素的铁磁性的新ⅡB型半金属;它的稳定相晶格常数约为0.623nm,分子磁矩约为1.0μB;Fe2LaO4属软铁磁性半金属;La较多的外层电子增强了Fe2LaO4内部的库仑斥力,导致了配合物ML4和ML6均受强场作用,从而使Fe2LaO4具有软铁磁性;考虑自旋分布后ML4和ML6的电子结构分别为a1g1↑a1g1↓t1u3↑t1u3↓eg2↑eg2↓t2g3↑t2g3↓和a1g1↑a1g1↓t1u3↑t1u3↓t2g3↑t2g3↓eg2↑eg2↓eg*1↑,这些电子属于分子轨道。 展开更多
关键词 Fe2lao4 新半金属 磁电性能 电子结构 分子磁矩
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劳(Lao)喷管扩张段优化设计的数值方法研究 被引量:1
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作者 周尚波 黎玉贵 +1 位作者 虞厥邦 廖哓峰 《宇航学报》 EI CAS CSCD 北大核心 2001年第5期66-71,共6页
本文建立了火箭发动机喷管扩张段优化设计 ( Lao喷管 )的型面曲线近似作图法的数学模型 ,将作图法转化为等价的优化问题 ,并给出了优化问题解的迭代方法 ,最后采用泛函网络的方法对离散的数值解进行了曲线拟合 ,以便于数控加工的编程。
关键词 火箭发动机 喷管 包络 优化设计 泛函网络 扩张段 lao劳喷管 迭代方法
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Dy^(3+)在(LaO)_3BO_3和(GdO)_3BO_3中的光致发光 被引量:3
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作者 刘利民 彭夷安 +1 位作者 李其华 雷春华 《湖南有色金属》 CAS 2000年第2期41-44,共4页
研究了Dy3 + 在(LaO) 3BO3 和(GdO) 3BO3 中的光致发光 ;探讨了基质晶体结构、稀土离子RE3 + 的电荷半径比 (Z/r)和Dy3 + 含量对(Dy3 + )发光强度及发光颜色的影响 ;分析了(GdO)3BO3 中Bi3 +对Dy3 +发光的敏化作用及Dy3 +4F9/2→6H13/2... 研究了Dy3 + 在(LaO) 3BO3 和(GdO) 3BO3 中的光致发光 ;探讨了基质晶体结构、稀土离子RE3 + 的电荷半径比 (Z/r)和Dy3 + 含量对(Dy3 + )发光强度及发光颜色的影响 ;分析了(GdO)3BO3 中Bi3 +对Dy3 +发光的敏化作用及Dy3 +4F9/2→6H13/2 超灵敏跃迁发射的自身浓度猝灭机理。 展开更多
关键词 DY^3+ (lao)3BO3 (GdO)3BO3 光致发光 浓度猝死
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LaO分子基态X^2Σ^+势能和平衡几何构型的比较研究 被引量:1
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作者 其木苏荣 《原子与分子物理学报》 CAS CSCD 北大核心 2003年第4期587-590,共4页
采用三种相对论有效核芯势 (LanL2DZ ,AREP ,RCEP)和价电子基组在MP2、B3LYP、CCSD(T)和QCISD(T)水平上计算了LaO分子基态平衡几何构型和能量 ,并对各种计算方法在不同基组下的计算效率和精度等进行了综合比较。在此基础上 ,选用B3LYP... 采用三种相对论有效核芯势 (LanL2DZ ,AREP ,RCEP)和价电子基组在MP2、B3LYP、CCSD(T)和QCISD(T)水平上计算了LaO分子基态平衡几何构型和能量 ,并对各种计算方法在不同基组下的计算效率和精度等进行了综合比较。在此基础上 ,选用B3LYP方法进行能量扫描得到了LaO分子势能曲线。计算得到的LaO分子基态平衡几何 ,振动频率、解离能和力常数等均与实验结果吻合。最后对赝势方法计算的误差原因进行了分析。 展开更多
关键词 lao分子 有效核芯势ECP 分析势能函数
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LaO_2对Al_2O_3—TiC_p/Al基复合材料组织结构的影响 被引量:1
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作者 耿在丹 张波 《河南广播电视大学学报》 2008年第3期109-110,共2页
利用Al—TiO2—C体系熔铸法制备含稀土LaO2原位自生Al2O3—TiCp/Al基复合材料,借助差示扫描量热仪(DSC)、扫描电子显微镜(SEM)、能谱分析仪(EDS)、X射线衍射仪(XRD)等测试技术,对Al—TiO2—C体系的组织结构进行了详尽的分析,讨论了稀土L... 利用Al—TiO2—C体系熔铸法制备含稀土LaO2原位自生Al2O3—TiCp/Al基复合材料,借助差示扫描量热仪(DSC)、扫描电子显微镜(SEM)、能谱分析仪(EDS)、X射线衍射仪(XRD)等测试技术,对Al—TiO2—C体系的组织结构进行了详尽的分析,讨论了稀土LaO2铝对Al2O3—TiCp/Al基复合材料的影响规律。实验结果表明,稀土LaO2的加入可改善陶瓷颗粒Al2O3和TiC与熔体的润湿性,而且有效细化和净化了组织,降低了反应温度。稀土LaO2添加剂含量为O.5%时利用熔铸法制备的复合材料中原位形成的Al2O3,TiC颗粒尺寸较小,分布均匀。 展开更多
关键词 lao2 原住自生 组织结构 Al2O3-TiCp/Al
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弛豫时间对BTO/LAO超晶格介电异常的影响
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作者 卢苇 肖定全 +1 位作者 于光龙 朱建国 《电子元件与材料》 CAS CSCD 北大核心 2005年第4期5-8,共4页
铁电材料钛酸钡(BaTiO3,简称BTO)与非铁电材料铝酸镧(LaAlO3,简称LAO)可以组成BTO/LAO铁电/非铁电超晶格。BTO/LAO超晶格的铁电、介电和热释电性能呈现新的变化特点。模拟计算了不同弛豫时间对不同层状周期结构的BTO/LAO超晶格介电性能... 铁电材料钛酸钡(BaTiO3,简称BTO)与非铁电材料铝酸镧(LaAlO3,简称LAO)可以组成BTO/LAO铁电/非铁电超晶格。BTO/LAO超晶格的铁电、介电和热释电性能呈现新的变化特点。模拟计算了不同弛豫时间对不同层状周期结构的BTO/LAO超晶格介电性能的变化规律;分析了BTO/LAO超晶格中的弛豫机制、Debye弛豫效应与Maxwell-Wagner效应之间的关系。模拟计算表明BTO/LAO超晶格在厚度为0.8nm/0.8nm~1.6nm/1.6nm时介电常数出现极值,与实验结果符合较好。超晶格的界面电荷的累积对于弛豫时间的作用直接影响了BTO/LAO超晶格的介电性能;BTO/LAO超晶格的介质损耗主要来源于BTO/LAO超晶格的电导率。 展开更多
关键词 无机非金属材料 BTO/lao超晶格 Debye弛豫 Maxwell-Wagner效应
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A Comparative Study of Lao Zi's Eco-philosophy and Western Contemporary Eco-philosophy
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作者 余梅娴 周文军 《海外英语》 2013年第23期5-8,共4页
Based on the brief introduction of western contemporary eco-philosophies and Lao Zi’s eco-philosophy,there will be an analysis of the differences according to historical context and critical target and their converge... Based on the brief introduction of western contemporary eco-philosophies and Lao Zi’s eco-philosophy,there will be an analysis of the differences according to historical context and critical target and their convergence.The analysis leads to the conclusion that eco-philosophies,whether contemporary or ancient,are against any form of domination and centrism. 展开更多
关键词 lao Zi WESTERN Eco-philosophy CONVERGENCE HISTORIC
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Visit China-Laos Year
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《China Report ASEAN》 2019年第2期8-8,共1页
Visit China-Laos Year 2019 was launched on January 25 in Vientiane, the capital of Laos.
关键词 China-laos YEAR launched laos
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(LaO)_3BO_3中Eu^(3+)和Sm^(3+)的光致发光 被引量:6
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作者 彭夷安 林建华 郭凤瑜 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 1996年第2期9-14,共6页
研究了紫外光激发下,(LaO)3BO3基质中Eu(3+)和Sm(3+)的光谱性质,Eu(3+)和Sm(3+)的电荷迁移激发带及发光强度随组成和结构变化的规律性,并探讨了Eu(3+)和Sm(3+)自身浓度淬灭的机理。
关键词 光致发光 浓度猝灭 硼酸盐
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弛豫时间对BTO/LAO铁电超晶格介电性能的影响
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作者 龚小刚 卢苇 +1 位作者 肖定全 朱建国 《四川大学学报(自然科学版)》 CAS CSCD 北大核心 2005年第S1期148-151,共4页
BaTi O3(BTO)与LaAlO3(LAO)组成的BTO/LAO超晶格的介电性能呈现新的变化特点.作者模拟计算了不同弛豫时间对不同层状周期结构的BTO/LAO超晶格介电性能的变化规律;模拟计算表明,BTO/LAO超晶格在厚度为0.8nm/0.8nm~1.6nm/1.6nm时介电常... BaTi O3(BTO)与LaAlO3(LAO)组成的BTO/LAO超晶格的介电性能呈现新的变化特点.作者模拟计算了不同弛豫时间对不同层状周期结构的BTO/LAO超晶格介电性能的变化规律;模拟计算表明,BTO/LAO超晶格在厚度为0.8nm/0.8nm~1.6nm/1.6nm时介电常数出现极大值.认为超晶格的界面电荷的累积对于弛豫时间的作用直接影响了BTO/LAO超晶格的介电性能;BTO/LAO超晶格的介电损耗主要来源于BTO/LAO超晶格的电导率. 展开更多
关键词 BTO/lao超晶格 Debye弛豫 Maxwell-Wagner效应
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BTO/LAO超晶格性能研究
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作者 陈涛 芦苇 朱建国 《电子科技大学学报》 EI CAS CSCD 北大核心 2008年第S1期54-57,共4页
利用横场伊辛模型,考虑四体相互作用,研究了BaTiO3/LaAlO3(BTO/LAO)铁电超晶格的居里温度、介电常数和极化强度与厚度周期的变化关系。发现BTO/LAO铁电超晶格的极化、居里温度和介电影响有显著的尺寸效应,耗散因子对BTO/LAO铁电超晶格... 利用横场伊辛模型,考虑四体相互作用,研究了BaTiO3/LaAlO3(BTO/LAO)铁电超晶格的居里温度、介电常数和极化强度与厚度周期的变化关系。发现BTO/LAO铁电超晶格的极化、居里温度和介电影响有显著的尺寸效应,耗散因子对BTO/LAO铁电超晶格的性能影响较大。随着耗散因子的减少,BTO/LAO超晶格的极化强度和居里温度增加,但介电常数几乎不变。当耗散因子σ=2.66时,模拟计算同实验结果相近,表明该理论模型可以作为研究BTO/LAO铁电超晶格的有效方法之一。 展开更多
关键词 BTO/lao 铁电超晶格 耗散因子 伊辛模型
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(LaO)_3BO_3基质中Tb^(3+)的发光特性 被引量:1
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作者 李其华 彭夷安 +2 位作者 刘利民 朱小娟 雷春华 《光谱实验室》 CAS CSCD 2001年第1期17-21,共5页
在 2 54nm紫外光 (UV)激发下 ,研究了 (La O) 3 BO3 基质中 Tb3 + 的激发光谱、发射光谱、发光寿命与Tb3 +浓度的关系 ,并探讨了 Tb3 +的 5D3 → 7F4 跃迁发射的自身浓度猝灭机理。在阴极射线 (CR)激发下 ,研究了 (L a O) 3 BO3 :Tb3 +... 在 2 54nm紫外光 (UV)激发下 ,研究了 (La O) 3 BO3 基质中 Tb3 + 的激发光谱、发射光谱、发光寿命与Tb3 +浓度的关系 ,并探讨了 Tb3 +的 5D3 → 7F4 跃迁发射的自身浓度猝灭机理。在阴极射线 (CR)激发下 ,研究了 (L a O) 3 BO3 :Tb3 + 的发光强度与 Tb3 + 浓度、加速电压及电流密度的关系。发现在 UV或 CR两种激发条件下 ,试样均能发出明亮的绿色荧光 。 展开更多
关键词 硼酸镧 光致发光 阴极射线发光 浓度猝灭 铽离子 掺杂
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Dialogue with Dr. Lixing Lao:from a factory electrician to an international scholar of Chinese medicine 被引量:3
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作者 Arthur Yin Fan 《Journal of Integrative Medicine》 SCIE CAS CSCD 2013年第4期278-284,共7页
Dr. Lixing Lao, an internationally known scholar of Chinese medicine renowned for his clinical and mechanisms research, is the Director of the Traditional Chinese Medicine (TCM) Program at the Center for Integrative... Dr. Lixing Lao, an internationally known scholar of Chinese medicine renowned for his clinical and mechanisms research, is the Director of the Traditional Chinese Medicine (TCM) Program at the Center for Integrative Medicine, University of Maryland (UM) School of Medicine; the Co-Chair of the Acupuncture Research Society; and the former Editor-in-Chief of the American Acupuncturist, the official journal of the American Association of Acupuncture and Oriental Medicine. The Baltimore Magazine has listed Dr. Lao as one of the nation's top acupuncture practitioners (Figure 1 ). 展开更多
关键词 traditional Chinese medicine acupuncture United States University of Maryland interview as topic history of medicine Dr. Lixing lao
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Food Security of Shifting Cultivation Systems: Case Studies from Luang Prabang and Oudomxay Provinces, Lao PDR 被引量:3
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作者 Linkham Douangsavanh Anan Polthanee Roengsak Katawatin 《Journal of Mountain Science》 SCIE CSCD 2006年第1期48-57,共10页
The Government of the Lao PDR’s policy is to eliminate the cultivation of upland rice by means of ‘slash-and-burn’ cultivation and to replace it with more ecologically stable systems based on sustainable land use a... The Government of the Lao PDR’s policy is to eliminate the cultivation of upland rice by means of ‘slash-and-burn’ cultivation and to replace it with more ecologically stable systems based on sustainable land use at the village and household level. The objectives of this policy are to alleviate poverty and to introduce more sustainable management of agricultural resources. In order to achieve these objectives, the government has initiated a program of relocation to upland ‘focal areas’ from which marketing, distribution and other services can be supplied, these being essential preconditions for effective agricultural development in these regions. This diagnostic study has examined communal and household strategies for addressing food security issues, and has highlighted the main problems encountered in the pursuit of food security on the local level. The specific objective was to conduct a broadly focused participatory problem diagnosis of the study areas in two districts Phonsay and Namo, in order to understand farmers’ problems, livelihood goals and how their perspectives on food security have changed, and to investigate food security in shifting cultivation systems in Luang Prabang andOudomxay provinces. Within these two provinces Phonsay and Namo districts were selected as the research areas. The two districts are the poorest districts in the Luang Prabang and Oudomxay provinces and two of ten priority poorest districts in the whole country. Semi-structured interviews were conducted for the study. The results of this study were reviewed against the sustainable land use systems strategy formulated from the Lao PDR policy. The study highlights both the benefits and stresses on household welfare, food insecurity conditions in the study areas, and interrelated problems of insufficient rice for household consumption. Finally based on these results the authors propose recommendations and future research indications. 展开更多
关键词 Shifting cultivation food security RICE sustainable land management lao PDR
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Identification of a Newly Isolated Getah Virus in the China-Laos Border,China 被引量:12
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作者 LI Yuan Yuan FU Shi Hong +12 位作者 GUO Xiao Fang LEI Wen Wen LI Xiao Long SONG Jing Dong CAO Lei GAO Xiao Yan LYU Zhi HE Ying WANG Huan Yu REN Xiao Jie ZHOU Hong Ning WANG Gui Qin LIANG Guo Dong 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2017年第3期210-214,共5页
In this study, we isolated a virus strain (YN12031) from specimens of Armigeres subalbatus collected in the China-Laos border. BHK-21 cells infected with YN12031 exhibited an evident cytopathic effect (CPE) 32 h p... In this study, we isolated a virus strain (YN12031) from specimens of Armigeres subalbatus collected in the China-Laos border. BHK-21 cells infected with YN12031 exhibited an evident cytopathic effect (CPE) 32 h post-infection. The virus particles were spherical, 70 nm in diameter, and enveloped; they also featured surface fibers. 展开更多
关键词 Getah virus China-laos border Phenotypic characteristics Molecular evolution
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Zircon U-Pb age,trace element and Hf isotope composition of Sepon Au-Cu deposit, Laos:tectonic and metallogenic implications 被引量:6
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作者 Xin-yu Wang Dian-hua Cao +2 位作者 Zong-qi Wang An-jian Wang Yu-dong Wu 《China Geology》 2018年第1期36-48,共13页
The Truong Son Fold Belt,located at the northeastern margin of the Indochina Block,is considered to be tectonically linked to the subduction of the Paleotethys Ocean and subsequent collision.Sepon is one of the most i... The Truong Son Fold Belt,located at the northeastern margin of the Indochina Block,is considered to be tectonically linked to the subduction of the Paleotethys Ocean and subsequent collision.Sepon is one of the most important super large deposits of the Truong Son Fold Belt.Our LA-ICP-MS zircon U-Pb dating results show that granodiorite porphyry samples from the Sepon deposit have ages of 302.1-4-2.9 Ma, which is a crucial phase for magmatic-tectonical activities from the Late Carboniferous to Early Permian and has avital influence on the mineralization of copper and gold.Zircon from granodiorite porphyry yields εHf (t)values of 4.32 to 9.64,and TDM2 has an average age of 914 Ma,suggesting that the source of the granodiorite porphyry in the region were mainly mantle components but underwent mixing and contamination of crust materials.The Ce^4+/Ce^3+ value of zircon in the granodiorite porphyry varys greatly from 2.4 to 1438.29,which shows magma mixing might occur.Considering the characteristics of trace elements in the zircon and the whole rock geochemical characteristics of intrusion rocks as well as the characteristics of regional volcanic-sedimentary association,it is indicated that the tectonic setting may be the continental arc environment.The Sepon Au-Cu deposit is derived from emplacement of calc-alkaline intermediate-acid magma with coming from deep sources in the subduction process of the Paleotethys Ocean,forming porphyry Mo-Cu,skam Cu-Au mineralization and a hydrothermal sedimentary-hosted Au mineralization in the wall rocks. 展开更多
关键词 Granodiorite PORPHYRY ZIRCON U-PB ages Hf isotope Trace elements Sepon laos
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