Integration of microdiffractive lens with continuous relief withvertical-cavity surface-emitting lasers using focused ion beam directmilling

A novel one-step integration of bottom-emitting vertical-cavity surface-emitting laser (VCSEL) (operation wavelength of 980 nm) with microdiffractive lens by means of focused ion beam (FIB) technology is described. A diffractive lens with continuous relief, diameter of 140 μm, and six annulus was designed and fabricated using FIB direct milling on the backside of VCSEL with GaAs substrate for beam collimation. The divergence angle (half angle) of the VCSEL was reduced from 12° before integration of the VCSEL/diffractive optical elements (DOEs) to 0.6° after FIB integration, allowing for an interconnect length of ~4 mm. It was proven by device testing that there is little influence upon the VCSEL performance after FIB processing     

运动平台上多基地雷达接收机中频率误差对测距的影响

针对运动平台上的多基地雷达,定量分析了接收机中频综与发射机工作频率之间的误差对测距的影响。     

Mc5—Ⅰ锻钢工作辊的研制

通过对有色铝板轧机后段工作辊的研制,开发了一种适应中等硬度中间辊及有色轧机工作辊的新型轧辊用材料。     

“书的联想”公共图书馆设计

介绍一公共图书馆建筑外形与结构选型的方案设计。建筑外观像由一本本书交错层叠而成,由书脊处的曲线分隔开阅览区与书库;结构方案采用交叉的拱与空间平板网架的组合,并在拱上覆膜。从而使得建筑造型优美轻盈,向外舒展,构造出大跨度的内部空间,令其外形与其自身功能、建筑与结构达到完美统一。     

建筑围护结构传热得热量计算方法的比较

比较了围护结构传热得热量的两种计算方法:周期性反应系数法和传递函数法。与传递函数法相比,周期性反应系数法简化了计算,而且周期性反应系数能反映围护结构对周期性扰量的热响应,可作为评价围护结构热稳定性的指标。推导了传递函数系数与周期性反应系数间的关系式,可根据ASHRAE的数据库RP 626建立典型围护结构周期性反应系数的数据库,从而减少周期性反应系数法的计算量。     

煤气中轻质油的测定

文章用实践证明，选用活性炭作为吸附剂，用于测定煤气中的轻质油是可行的，且具有装置简单、操作方便、测定时间短、精密度好等优点。     

点评——哈达铺镇、里耶镇、麻扎村

红军长征重大活动决策地——哈达铺哈达铺,原名哈塔川,明代设铺后更名叫哈达铺,其所属的宕昌县历史悠久,早在新石器时代就有人类繁衍生息。西周时羌人居住,西晋永嘉元年,羌族首建宕昌国,隋朝时建宕昌郡,唐武德元年改为宕州。1954年宕昌建县。哈达铺是中国工农红军长征途中唯一一处一、二、四三个方面军都经过此地,并在此进行重大活动的决策地,是一处包括保存较为完整的五处纪念性革命旧址和一条近千米的清末民初历史街道的重要现代文物遗存。哈达铺自古盛产药材,这条老街是清末以来,陕西、上海、湖南、山西、天津等十一省客商来此开设经营药…     

寻求舒适性与可持续发展的平衡点——一座德国幼儿园的改造给我们的思考

保持建筑的舒适度和建筑的可持续发展是一对矛盾.主要对德国的一座幼儿园改造进行调查和分析,希望能通过对它的介绍对我国建筑的发展有启示作用.     

Synthesis and optical characterization of Pd–Au bimetallic nanoparticles dispersed within monolithic mesoporous silica

Au–Pd bimetallic nanoparticles dispersed within pores of monolithic silica was synthesized by soaking Au nanoparticles contained silica host into Pd precursor solution and subsequent step-annealing at temperature from 373 to 773 K. Theoretical optical spectra based on Mie-like model for Au_corePd_shell nanoparticles yield excellent agreement with the experimental results.     

A study on centrifugal casting of high speed steel roll

High speed steel (HSS) rolls can replace traditional rolls such as alloyed cast iron rolls and powder metallurgical (PM) hard alloy rolls. The main reasons for the replacement are that the wear resistance of low-cost alloyed cast iron rolls is poor and the cost of high-quality PM hard alloy rolls is very high. By means of centrifugal casting, HSS rolls having excellent wear resistance have been manufactured. The hardness of the HSS roll is 65～ 67 HRC, the range of variation is smaller than 2 HRC and its impact toughness is 15 J/cm2. The wear rate of HSS rolls used in the pre-finishing stands of high-speed hot wire-rod rolling mill reaches 2.5 × 10-4 mm per ton steel. Furthermore, the manufacturing cost of HSS rolls is significantly lower than that of PM hard alloy rolls; it is only 30 percent of that of PM hard alloy rolls.