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请用英文叙述一下中国的地理位置。

2023-08-18 22:46:07
共1条回复
Chen

Located in the east of the Asia-Europe Continent, on the western shore of the Pacific Ocean, China has a land boundary of some 20,000 km, with 15 neighboring countries.

  China"s mainland coastline extends from the Yalu River on the border with North Korea in the north to the Beilun River on the border of China and Vietnam in the south, measuring approximately 18,000 km. The Chinese mainland is flanked to the east and south by the Bohai, Yellow, East China and South China seas. A total of over 5,000 islands dot China"s territorial waters. The largest of these is Taiwan. The island coastline measures approximately 14,000 km.

  China is bordered by Korea to the east; Mongolia to the north; Russia to the northeast; Kazakhstan, Kyrgyzstan and Tajikistan to the northwest; Afghanistan, Pakistan, India, Nepal, Sikkim and Bhutan to the west and southwest; and Vietnam, Laos and Myanmar to the south.

  Across the seas to the east and southeast of China are Japan, the Republic of Korea, the Philippines, Malaysia, Indonesia and Brunei.

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2023-08-11 02:34:431

用英文介绍江苏省在中国的地理位置

Jiangsu is a province of the People"s Republic of China, located along the east coast of the country.Jiangsu borders Shandong in the north, Anhui to the west, and Zhejiang and Shanghai to the south. Jiangsu has a coastline of over one thousand kilometers along the Yellow Sea, and the Yangtze River passes through its southern parts. Since the inception of economic reforms in 1978, Jiangsu has been a hot spot for economic development, and is now one of China"s most prosperous provinces.
2023-08-11 02:34:501

光毒性和细胞毒性的区别

http://baike.baidu.com/view/571655.htm光毒性 开放分类: 生物强烈的阳光中的紫外线本身就能够造成严重的日光性皮炎,甚至皮肤癌。许多药物对人体不会造成伤害,但在阳光中的紫外线的作用下,渗入人体皮肤蛋白质中的这些药物便会发生化学反应,从而引发皮肤过敏症。强烈的阳光可使药物活化,直接破坏或杀死皮肤细胞,使暴露在光线下的皮肤在日晒后的几分钟或几小时内产生轻度的光毒性反应,其症状类似于日晒斑或日光性皮炎。而且引发皮肤癌的风险也比常人更大。 可引起光毒性的药物有:喹诺酮类抗菌素、布洛芬、格列本脲、格列吡嗪、四环素类、米诺环素、磺胺类、多西环素、地美环素、氢氯噻嗪、氯丙嗪等。 临床主要表现为在光照皮肤处出现红肿、发热、瘙痒、疱疹等症状。服用的药物量越大,在阳光下暴晒的时间越长,过敏反应则越严重,皮肤瘙痒将持续24~48小时,甚至更长的时间。 这种光敏反应发生的频率和严重程度因人而异,一部分患者在短暂接触光线后就可能出现水疱,但大多数人仅有轻微的甚至可能是很难察觉的反应。有人即使口服一次也可发生。即使在多云天气条件下,这些药物也会使一些患者的皮肤产生不同程度的过敏反应。与普通人相比,光毒性反应更容易发生在皮肤娇嫩者、因痤疮正在使用抗生素治疗的少儿、老人、女性,以及人体免疫缺陷病、红斑狼疮、免疫功能受损的患者身上。因此,这些人在使用沙星类抗生素等药物时必须采取适当的防护措施,以避免光毒性反应的损害。这些措施包括: 1.在使用喹诺酮类等药物期间及停药后5日内,应避免接触阳光或紫外线,如出现光毒性反应或皮肤损伤,应立即停用药物,并去皮肤科就诊,不要自作主张乱用药,以免延误病情。 2.已发生光毒性反应的患者,在症状未消失时及症状消失后5日内,仍不能接受太阳光或紫外线照射,以免再次发生光毒性反应。 3.有光毒反应史的患者要慎用这类药物。 4.易感人群在使用有光毒反应的药物期间,外出应特别注意皮肤防护,出门时可选用防晒指数为15或者更高的防晒霜,或者打遮阳伞。目前人们使用防晒霜、防晒油或防晒乳液对隔离紫外线保护肌肤只能起到部分效果。细胞毒性是由细胞或者化学物质引起的单纯的细胞杀伤事件,不依赖于凋亡或坏死的细胞死亡机理。有时需要进行特定物质细胞毒性的检测,比如药物筛选。细胞毒性检测主要是根据细胞膜通透性发生改变来进行的检测,常用以下几种方法:MTT、XTT法:利用线粒体内部酶的活性,可以将特定的四唑盐类进行转化,然后通过酶标仪进行检测LDH的方法:通过检测细胞培养上清中LDH的酶活性,来检测细胞毒性其它酶方法:如检测上清中碱性磷酸酶、酸性磷酸酶的活性等细胞增殖能力分析试剂盒原理:正常细胞代谢旺盛,其线粒体内的琥珀酸脱氢酶,可将四唑盐类物质(如 MTT、XTT、WST-1等 )还原为紫色的结晶状的物质,沉积在细胞周围,然后通过酶标仪读取OD值,从而检测到细胞增值状态荧光素发光法细胞生存能力检测试剂盒原理:腺苷酸激酶(AK)存在于所有真核和原核细胞的胞浆中,AK具有激活ADP生成ATP。当细胞受损后,细胞膜发生破损,AK会释放到培养上清中。该试剂盒利用荧光素酶和荧光素在ATP作用下可以发光,通过化学发光仪可以定量进行检测。LDH法细胞毒性检测试剂盒原理:LDH(乳酸脱氢酶)是一种稳定的蛋白质,存在于正常细胞的胞质中,一旦细胞膜受损,LDH即被释放到细胞外; LDH催化乳酸形成丙酮酸盐,和INT(四唑盐类)反应形成紫色的结晶物质,可通过500nm酶标仪进行检测。通过检测细胞培养上清中LDH的活性,可判断细胞受损的程度http://www.jingmei.com/site/site/news/e200401/chapter7.jsp
2023-08-11 02:26:551

高中物理多用电表怎么读数,下面的档数该怎么用

3、多用表的读数方法(1)测电阻:万用表刻度盘面上一般标有3~4组刻度线,一般最上面的是欧姆档的,欧姆档的刻度线不是从左到右读得,而是从右到左0、1、2、3、4、5、10……无穷大(这是倍率)。测电阻时黑表笔的电势高 中值电阻等于内阻!!选好档位,用表笔分别连接电阻的两端,等指针不动了读倍率,用档位乘以倍率,就可以得到阻值了。实验室用多用电表实验室用多用电表(2)测电流:如用“直流10mA档测量电流”中的10mA 去除以250mA(电流最大那个标250MM的)乘以图中所表示的数字 (用“直流1mA档测量电流”档看(0—250)“直流100mA档测量电流”的看中间的,“直流10mA档测量电流”的看最下的) 测电压也一样。(3)注意事项:所有电表的使用,还有一个要求:选择合理的档次,致使指针停留在表盘刻度的“13---23”之间。这不是一个严格要求,但必须考虑这个“原则”。1.换挡必调零:红黑表笔短接。2.读数时尽量选择中间刻线。3.红进黑出。4.读数时,指针靠近哪个格读哪个数。5.除欧姆档非十分度部分外,都需要估读。
2023-08-11 02:26:564

家用RO反渗透纯水机的结构原理

纯水机的净水系统是以反渗透膜为核心的,反渗透膜之前的部分可称为前处理,反渗透膜之后称为后处理,下面对其进行分别分绍:1、前处理  前处理是对原水进行初级净化,为反渗透膜提供水源。其主要作用是保护反渗透膜。前处理必须具备的两级滤芯:沉淀滤芯、活性碳滤芯。前置活性碳芯不仅能去除原水中的异嗅、异味,还可对水的浊度、色度、有机物、铁、酚、F、As、Hg、Al、CHCl3、CCL4、余氯等具有明显降低作用。通过去除自来水中余氯,可防止氧化性极强的氯对反渗透膜的损坏。前处理还可以根据需要增加树脂滤芯,降低原水的硬度,防止反渗透膜表面结垢。2、纯水机RO膜是具有选择性分离功能的材料。利用膜的选择性分离实现料液的不同组分的分离、纯化、浓缩的过程称作膜分离。它与传统过滤的不同在于,膜可以在分子范 围内进行分离,并且这过程是一种物理过程,不需发生相的变化和添加助剂。膜的孔径一般为微米级,依据其孔径的不同(或称为截留分子量),可将膜分为微滤 膜、超滤膜、纳滤膜和反渗透膜,根据材料的不同,可分为无机膜和有机膜,无机膜主要还只有微滤级别的膜,主要是陶瓷膜和金属膜。有机膜是由高分子材料做成的,如醋酸纤维素、芳香族聚酰胺、聚醚砜、聚氟聚合物等等。 膜分离过程:膜是每一膜过程的核心部件,它可以看成是两相之间一个具有透过选择性的屏障,或看作两相之间的界面,膜分离过程可由原料或上游, 渗透物或下游。原料混合物中某一组分可以比其他组分更快的通过膜而传递到下游侧,从而实现分离。3、后处理纯水机的后处理可采用活性碳滤芯、紫外线灭菌灯等。后置活性碳滤芯的作用是将反渗透膜制造的纯水进行深度处理,去除水中挥发性有机物、气味、改善纯净水的口感。尤其是使用压力式储水桶的纯水机,后置活性碳能有效去除储水桶产生的橡胶味。紫外线灭菌灯经常在高档纯水机上使用,可防止纯净水被二次污染。4、增压泵和控制系统由于反渗透膜需要0.4-0.8MPa的原水压力,所以纯水机净水系统必须加装专门的增压泵。增压泵一般采用24V直流电源,由水位开关或压力开关进行控制。
2023-08-11 02:26:561

伺服电机工作原理是什么

伺服电机的工作原理:伺服电机接收到1个脉冲,就会旋转1个脉冲对应的角度,从而实现位移。因为,伺服电机本身具备发出脉冲的功能,所以伺服电机每旋转一个角度,都会发出对应数量的脉冲。这样和伺服电机接受的脉冲形成了呼应,或者叫闭环。如此一来,系统就会知道发了多少脉冲给伺服电机,同时又收了多少脉冲回来。它就能够很精确的控制电机的转动,从而实现精确的定位,可以达到0.001mm。直流伺服电机分为有刷和无刷电机。有刷电机成本低,结构简单,启动转矩大,调速范围宽,控制容易,需要维护,但维护不方便,产生电磁干扰,对环境有要求。因此它可以用于对成本敏感的普通工业和民用场合。伺服电动机的转子通常做成鼠笼式,但为了使伺服电动机具有较宽的调速范围、线性的机械特性,无“自转”现象和快速响应的性能。
2023-08-11 02:26:581

冯诺依曼结构计算机的基本思想是( )

冯诺依曼结构计算机的基本思想是存储程序、程序控制、程序和数据以二进制表示。根据冯诺依曼体系结构构成的计算机,必须具有如下功能:1、把需要的程序和数据送至计算机中。2、必须具有长期记忆程序、数据、中间结果及最终运算结果的能力。3、能够完成各种算术、逻辑运算和数据传送等数据加工处理的能力。4、能够根据需要控制程序走向,并能根据指令控制机器的各部件协调操作。5、能够按照要求将处理结果输出给用户。为了完成上述的功能,计算机必须具备五大基本组成部件,包括:1、输入数据和程序的输入设备;2、记忆程序和数据的存储器;3、完成数据加工处理的运算器;4、控制程序执行的控制器;5、输出处理结果的输出设备。扩展资料1945年6月,冯·诺依曼提出了在数字计算机内部的存储器中存放程序的概念(Stored Program Concept),这是所有现代电子计算机的模板,被称为“冯· 诺依曼结构”,按这一结构建造的电脑称为存储程序计算机(Stored Program Computer)。冯·诺依曼计算机主要由运算器、控制器、存储器和输入输出设备组成,它的的特点是:程序以二进制代码的形式存放在存储器中;所有的指令都是由操作码和地址码组成。指令在其存储过程中按照执行的顺序进行存储;以运算器和控制器作为计算机结构的中心等。冯诺依曼计算机广泛应用于数据的处理和控制方面,但是存在一定的局限性。参考资料来源:百度百科-冯·诺依曼结构计算机
2023-08-11 02:27:021

金属贮氢原理

传统贮氢方法有两种,一种方法是利用高压钢瓶(氢气瓶)来贮存氢气,但钢瓶贮存氢气的容积小,瓶里的氢气即使加压到150个大气压,所装氢气的质量也不到氢气瓶质量的1%,而且还有爆炸的危险;另一种方法是贮存液态氢,将气态氢降温到-253 0C变为液体进行贮存,但液体贮存箱非常庞大,需要极好的绝热装置来隔热,才能防止液态氢不会沸腾汽化。近年来,一种新型简便的贮氢方法应运而生,即利用贮氢合金(金属氢化物)来贮存氢气。 研究证明,某些金属具有很强的捕捉氢的能力,在一定的温度和压力条件下,这些金属能够大量“吸收”氢气,反应生成金属氢化物,同时放出热量。其后,将这些金属氢化物加热,它们又会分解,将贮存在其中的氢释放出来。这些会“吸收”氢气的金属,称为贮氢合金。 贮氢合金的贮氢能力很强。单位体积贮氢的密度,是相同温度、压力条件下气态氢的1000倍,也即相当于贮存了1000个大气压的高压氢气。
2023-08-11 02:27:063

雅马哈YST-SW011怎么样?雅马哈YST-SW011好吗

很不错,音质达到预期,当然跟HIFI是没法比的,家庭影院或者听听歌可以了。我另卖了雅马哈的RX-V375功放配了YST-SW11低音炮,这个功放有一个HDMI接口是带ARC音频回传功能的,如果你的电视机也有带ARC功能的HDMI,就可以和该功放实现ARC音频回传功能。如果你的电视机没有带ARC功能的HDMI接口,如果有光纤音频接口的话,配根光纤音频线也能实现音频回传
2023-08-11 02:27:081

简要说明储氢合金的吸放氢过程

储氢合金吸氢时,首先是氢气吸附于合金表面,在合金表面元素的催化作用下分解为氢原子,然后氢原子进入到储氢合金内部晶格的四面体和八面体间隙中,这个时候的氢在合金中是随机分布的,把这种状态下的合金称之为含氢固溶体。合金继续吸氢后,储存于合金晶格中四面体和八面体间隙的氢会与合金反应,形成真正的储氢合金,此时的氢在合金中是平均分布的。当合金中的氢的储存量达到其在特定温度和压力下的最大储氢量时,氢不能再继续进入合金,此时吸氢过程结束,放氢过称为上述吸氢过程的逆反应。
2023-08-11 02:27:161

什么是冯诺依曼计算机的基本思想?

冯诺依曼计算机的基本思想是:数字计算机的数制采用二进制;计算机应该按照程序顺序执行。美籍匈牙利科学家冯·诺依曼最先提出程序存储的思想,并成功将其运用在计算机的设计之中,根据这一原理制造的计算机被称为冯·诺依曼结构计算机。由于他对现代计算机技术的突出贡献,因此冯·诺依曼又被称为“现代计算机之父”。根据冯诺依曼体系结构构成的计算机,必须具有如下功能:把需要的程序和数据送至计算机中。必须具有长期记忆程序、数据、中间结果及最终运算结果的能力。能够完成各种算术、逻辑运算和数据传送等数据加工处理的能力。能够根据需要控制程序走向,并能根据指令控制机器的各部件协调操作。扩展资料:冯·诺伊曼参加原子弹的研制工作,该工作涉及到极为困难的计算。在对原子核反应过程的研究中,要对一个反应的传播做出“是”或“否”的回答。解决这一问题通常需要通过几十亿次的数学运算和逻辑指令,尽管最终的数据并不要求十分精确。但所有的中间运算过程均不可缺少,且要尽可能保持准确。他所在的洛·斯阿拉莫斯实验室为此聘用了一百多名女计算员,利用台式计算机从早到晚计算,还是远远不能满足需要。无穷无尽的数字和逻辑指令如同沙漠一样把人的智慧和精力吸尽。
2023-08-11 02:26:491

雅马哈低音炮型号yst一swo11多少钱?

雅马哈低音炮型号yst-swo11这个的价格在3000多块钱左右,这个在618的时候官网有活动
2023-08-11 02:26:481

关于两个生物问题

口诀:无中生有为隐性,隐性遗传看女病,父子都病为伴性。有中生无为显性,显性遗传看男病,母女都病为伴性。只有父子病为伴Y。第二题:1:Tt XTt-----> F1: TT , 2Tt, tt F2:TT X TT------>1/4 *1 =1/4 TT X Tt-------->1/4*1/2*1/2=1/16 Tt X Tt-------->1/2*1/2*1/4=1/16 TT出现的概率为:1/4+1/16+1/16=3/8望采纳 谢~
2023-08-11 02:26:464

高二物理,选修3—1,如图多用电表示意图,请问开关S接3和接4变成的欧姆表有何区别?范围都是[0,

用(A、1),多用表当大量程的电流表;用(A,2)多用表也是当电流表用,只是它的量程小一点罢了。用(A、3)、(A、4)接线柱,多用表都当欧姆表使用,只是后者是测量较大阻值的电阻,前者是测量较小阻值的电阻的。用(A,5)、(A、6)接线柱,多用表当电压表使用,后者的测量范围较大。
2023-08-11 02:26:451

对储氢合金材料有哪些要求

储能材料不仅能存储能量,并且能使能量转化,以供需用。最常见的储能材料有储氢合金和用于一次电池(即原电池,放电后不能复原使用)、二次电池(即蓄电池,放电后可重新充电复原反复使用)的材料。常见的一次电池有锌–二氧化锰电池、锌–氧化汞电池、锌–氧化银电池和锂电池等。常见的二次电池为铅–酸电池、镍–镉电池、镍–锌电池和镍–氢化合物电池、钠–硫电池、锂离子电池等。 1、储氢合金 氢是自然界中储量最大的元素,也是一种非常清洁的能源。储氢合金所存储的氢的密度比液态氢大得多(液氢的密度为4.2×1022大气压/厘米3,而LaNi5的氢密度为6.2×1022大气压/厘米3),并且释放氢时所需的能量很小。 2、储氢合金应用要求 储氢合金的工作压力很低,操作简单安全可靠。研发中的储氢合金体系有AB5型混合稀土合金、AB2型Laves相合金、AB型钛铁系合金、A2B型Mg–Ni系合金和钒基固溶体合金等。储氢合金与气体氢发生反应时生成金属氢化合物,大量的氢以固态形式储存于储氢合金中。储氢合金的吸氢与放氢,实际上就是金属氢化物的形成与分解。 3、储氢合金的基本特征是:能可逆地大量吸氢和放氢,伴随着吸(放)氢过程出现放(吸)热效应,对氢能选择性地吸收,吸放氢的平衡压力随温度急剧变化。 4、储氢合金可用于镍–氢化合物电池、氢的储存和净化、氢同位素分离、氢气回收、热泵、制冷等。
2023-08-11 02:26:451

雅马哈yst-sw105主音箱不响

1、选择了其他输入源。 解决方法:请选择合适的输入源。 2、启用了静音功能。 解决方法:取消静音功能。 3、音量太小。 解决方法:调高音量。 4、条形音箱的电源线连接不正确。 解决方法:确保条形音箱的电源线已牢固连接至交流电源插座。 5、均连接在两部装置的输入插孔中。 解决方法:将条形音箱的输入插孔连接至外部播放装置的输出插孔。 6、正在输入条形音箱无法播放的信号。 解决方法:将播放装置上的数字音频输出设置更改为 PCM 或 Dolby Digital。
2023-08-11 02:26:401

实验室纯水系统的工作原理

采用先进的反渗透技术和离子交换技术相结合的方式,采用微电脑单板机程序控制,水质检测自动显示,从而获得了高质量的产出水,它的出水电阻率一般均可达到18MΩ/cm。设备使用的增压泵、电磁阀、高容量离子交换树脂、R.O反渗透膜、滤芯、管路连接件、控制原件、紫外灯等均采用国外进口的产品。 超纯水机的反渗透原理是在原水一方施加比自然渗透压力更大的压力,使水分子由浓度高的一方逆渗透到浓度低的一方 。由于反渗透膜的孔径远远小于病毒和细菌的几百倍乃至上千倍以上,故各种病毒,细菌, 重金属,固体可溶物,污染有机物,钙镁离子等根本无法通过反渗透膜,从而达到水质净化的目的。 实验室超纯水系统特点: 1)工作压力高,不漏水:由于模块采用了橡胶O型圈多层密封,保证了模块耐压高、不漏水。 2)无化学物质使用:由于浓水中填充了专利树脂,降低了膜电阻,因此系统中不需要浓水循环及注盐在淡水室填充分层排列树脂,更有利于弱电解质的祛除。 3)系统简单,配管简单,仅需3支配管(进水管,产品水管和浓水管),无循环泵及注盐系统,不需要 PLC 程序控制器,系统建造成本和维护费用低。 4) 浓水回收,浓水水质( 20-100 μ S/cm )优于原水水质,可回收至 RO 前继续使用。
2023-08-11 02:26:401